|Publication number||US3535676 A|
|Publication date||Oct 20, 1970|
|Filing date||Feb 12, 1968|
|Priority date||Feb 12, 1968|
|Also published as||DE1905734A1, DE1905734B2, US3539973|
|Publication number||US 3535676 A, US 3535676A, US-A-3535676, US3535676 A, US3535676A|
|Inventors||Harold R Schultz Sr|
|Original Assignee||Hughes Aircraft Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (31), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Oct. 20, 1970 H..R. SCHULTZ. SR
ELECTRICAL CONNECTOR 4 Sheets-Sheet 1 Filed Feb. 12, 1968 Oct. 20, 1970 an. SCHULTZ. SR
ELECTRICAL CONNECTOR 4 Sheets-Sheet 2 Filed Feb. 12, 1.968
H. R. SCHULTZ. SR
ELECTRICAL commc'ron 4 Shets-Sheet 3 Filed Feb. 12, 1968 United States Patent Office 3,535,676 Patented Oct. 20, 1970 3,535,676 ELECTRICAL CONNECTOR Harold R. Schultz, Sr., Los Angeles, Calif., assignor t0 Hughes Aircraft Company, Culver City, Calif., a corporation of Delaware Filed Feb. 12, 1968, Ser. No. 704,869 Int. Cl. H01r 13/46 US. Cl. 339-143 20 Claims ABSTRACT OF THE DISCLOSURE A connector providing radio frequency shielding and preventing propagation of unwanted noise into electronic equipment. Two mating connector sections are oppositely mountable on the apertured equipment frame. One of the connector sections comprises a connector body and a conductive material filled rubber or elastomer gasket cemented together, a surrounding flanged radio frequency interference shield configured and attached to the frame to constrict the gasket, a connector contact support block which covers a top aperture of the shield and into which a plurality of connector contacts are inserted, and connecting jack screw means. The block member, gasket, and body have a plurality of transverse apertures to removably retain selectively filter connector or ordinary connector contacts which may be pin or socket contacts. The connector body and block apertures are of larger diameter than the diameter of the contacts. Each filter contact comprises a tubular pi filter having an external capacitor plate from which noise frequency energy passes through the conductive gasket to the grounding shield. The gasket contact retaining apertures are relatively critically sized for interference fit with relation to the contact filter diameter for protective but removable retention of the contacts and such that the contacts are in engagement with and deform the gasket for increased conductivity. The shield and gasket are of structure, configuration, and material so that pressure on the gasket of the retained filter contacts and pressure on the gasket of the secured shield substantially grounds certain unwanted high frequency noise through the gasket to the shield.
BACKGROUND OF THE INVENTION Field of the invention The present invention relates to improved multi-contact electrical connectors. More particularly it relates to such connectors wherein without sacrifice of number and significant size of connector contact sockets and pins, stray or extraneous incoming RF energy is reduced to a level where the electrical noise or interference will not prevent receiving usable electronic signals.
Description of the prior art Connectors wherein multiple grounding connections are provided are described in US. Pat. No. 3,231,843 of J. E. Antes et al. for Grounding Connector, issued Jan. 25, 1966. Multicontact connectors which incorporate a similar jack screw means for securing and indexing the connector bodies containing a plurality of closely spaced contact pins and sockets are described in U.S. Pat. No. 3,281,761 of M. L. Moulin, for Connector Securing Device, issued Oct. 25, 1966 and assigned to the assignee of the present invention. The disclosure of the Moulin Pat. 3,281,761, is incorporated by reference in the present application. While the connector of the Moulin Pat. 3,281,761 is a very desirable connector for many purposes it does not provide the means of the present invention which, without decreasing the space allotted for contact pin and socket elements, incorporates filter, shielding, and
grounding means whereby unwanted noise or signals, particularly at high frequencies are bypassed to ground or reflected back while allowing the desired electrical signal voltages to pass through the contact pins and sockets of the connector.
Prior art devices attempted to solve the problems by less advantageous or unsuitable means by employing electrical filter networks made up of discrete components, i.e., capacitors, resistors, and/or inductors and miniaturized versions of these, or by providing larger connectors and inserting separate filters in the additional space provided. Also, such prior art devices do not provide removable enclosures with removable contact pins and sockets that can be closely spaced together and do not effectively ground out the unwanted signals. They do not provide shielding means to substantially totally isolate the structure from unwanted radio frequency energy. Prior art devices require additional space-consuming and/or costly radio frequency (RF) gasketing devices to minimize RF leakage paths.
The present invention overcomes these and other disadvantages of prior art devices. The invention provides a connector which is capable of efficient overall shielding effectiveness. It provides removable connector contact pins and sockets and removable filter connector contact pins and sockets in conjunction with means to permit attenuation of stray or extraneous RF energy to a level where the signal noise or interference will not prevent receiving a usable electrical signal. The invention further solves problems where interconnection leads traversing a shield wall must be decoupled in order to prevent the conduction of RF energy into and out of the shielded enclosure via the leads. The invention further provides a filter that is usable in existing available space in a connector without changing the contact pin density and without losing the environmental shield and which further provides RF shielding of the opening required for a connector which is mounted in a shield wall.
Thus, the invention provides a device wherein available space in a connector is utilized without loss in contact member density, the same connector body may be used without changes being required to insert selectively either filter pin or socket contact elements or alternatively blocking (without a filter) pin or socket contact element and provides a shielding and grounding means which effects both shielding of the connector and grounding of unwanted frequencies in the signals coming through the contact elements of the connector. The invention further provides an RF noise grounding means which eliminates much of the weight increase normally expected by the addition of filtering components and wherein failure due to metal fatigue is minimized.
SUMMARY OF THE INVENTION Accordingly an object of the present invention is to provide a connector adapted to mate with a wide variety of electrical equipment, which without requirement for additional space in the connector body, provides subsfantially total shielding, and filters and grounds substantial amounts of noise signals of certain ranges of frequencies entering into the leads traversing the shield enclosure.
Another object of the present invention is to provide a connector with a shield wall enclosure structure and removable interconnection lead coiuiected contact pins or sockets which traverse the shield wall and wherein the contact pins or sockets are modified to provide decoupling and wherein means are incorporated to prevent the conduction of certain radio frequency energy through the shielded enclosure wall via the leads.
Still another object of the present invention is to provide a connector incorporating a filter connector contact means, an RF shield, and grounding means that is structured to tfit within existing available space taken up by the connector without changing the contact socket or pin density and without losing the environmental shielding and in addition which will provide RF shield ing of the openings required for the connectors when mounted in a shield wall.
Another object of the present invention is to provide a connector with alternatively insertable substantially similarly dimensioned and configured filter and regular contacts, wherein already available space in the connector is utilized without loss in contact member density, wherein a grounding means is provided which also shields the opening caused by the presence of the connector body, where substantially no weight increase is necessitated by the additional filter, grounding, and shielding functions and metal fatigue is substantially avoided.
Another object of the invention is to provide in a connector section a means to ground the capacitors of filter contact sockets or pins to a reference ground which is the Wall of a shielding hood enclosure secured to a frame wherein a deformable conductive member with preformed undersized apertures interferingly contact an outside capacitor plate of each filter pin or socket in the connector section and wherein the hood extends around and electrically contacts the periphery of the deformable member and is dimensioned to compress the deformable member traversely.
According to the present invention there is provided an electrical connector particularly for connecting into and out of electrical equipment while providing shielding and minimizing or reducing of noise passage therethrough comprising: superimposed connector body and deformable conductive gasket members, each having a plurality of laterally closely spaced, transverse connector contact receiving apertures therethrough. The gasket and body apertures are respectively aligned. A grounding and radio frequency interference shielding hood surrounds the gasket and body means and may comprise a flange. Securing means connect the hood means, gasket and body under tension to a frame to provide a shielding enclosure wherein the gasket is compressed. Connector filter contact pins or sockets are removably inserted in the aligned apertures. The connector body is provided with apertures of greater than contact diameter to receive a contact inserting and removing tool therebetween. The deformable gasket is provided with critically undersized apertures for contacting the filter, for example, contacting a capacitor plate of each filter of the connector contacts when inserted into the aligned apertures in the connector body and in the gasket. The conductive flexible material gasket which may comprise an elastomer or a rubber material impregnated with conductive particles prevents unwanted inductance and therefore shared coupling and cross talk by grounding unwanted signals to the hood. The radio frequency interference shielding hood provides both better electrical connection and mechanical rigidity due to its flanged and large contact area configuration. The gasket material is subject to both transverse hood compression against the edges of the top surface and lateral and longitudinal compression because of the aperture diameter being critically smaller than the contact or socket diameter. The top compression at the gasket edges is provided by flange securing means inasmuch as the depth from the inner hood top face is less than the connector body and attached gasket thickness. The central gasket, connector body, and a block means may be secured together and connector section polarizing and other structural alignment obtained by jaok screw and spanner nut means. The connector contact pins and sockets may be held in place by an encircling outwardly flaring spring member and the invention provides for the required room for tool entry to compress the flaring portion of the spring for disassembly of the contact. This is provided by the abovedescribed space due to the connector body aperture diameter being made larger than the connector filter contact outside diameter provided by the invention. The gasket interference fitting size apertures of the invention into which the contacts are inserted provides good electrical connection of the filter to the conductive gasket and thus to ground, provided yieldable but firm support for the otherwise loosely fitting fragile pin and prevents RF energy from leaking through along the aligned apertures. The invention further provides that the gasket be manufactured by a process to render it satisfactorily corrosion resistant, that the gasket contain an amount of embedded conductive material and be of material, softeness, shape and structure for proper compressibility to provide the necessary conductivity at the frequencies of energy required to be grounded.
The foregoing and other objects and attendant advantages, features and uses of the devices embodying the invention will become more apparent to those skilled in the art as a more detailed description proceeds when considered in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view illustrative of a first preferred embodiment of the invention showing the elements of a first connector section and the body of a second connector section in position to be assembled and mounted to the frame of a unit of electrical equipment, for clarity illustrating only one filter connector socket contact in position to be fitted into the aligned apertures of the block, deformable conductive gasket, and connector body and illustrating the radio frequency interference shield can, the can securing means and the jack screw aligning and securing means of the preferred embodiment;
FIG. 2 is an enlarged view of the filter contact socket element of FIG. 1;
FIG. 3 is a schematic diagram illustrating the electrical equivalent of the filter and grounding provided in the embodiment of FIGS. 1 and 2;
FIG. 4 is a side view of the first connector section of FIG. 1 in assembled relationship and with portions broken away to present sectional views of the elements to facilitate the explanation of the invention;
FIG. 5 is a side view partly in section of a male connector section having elements similar to those of the illustrative embodiment of FIGS. 14 but showing a modified connector body and a seal member to render the section more suitable for retaining connector filter contact pins instead of filter contact sockets;
FIG. 6 is a diagrammatic side representation of a small portion of a connector section similar to the embodiment of FIG. 5 illustrating the deformation of a conductive material filled thin flexible or deformable material gasket by a retained filter contact pin and the thereby enhanced conductive path through the deformed conductive material to the grounding hood;
FIG. 7 is an end view in the direction of lines 77 of FIG. 6 illustrating the puckering effect of two adjacent contact pins retained in the deformable conductive gasket to facilitate explanation of the enhancement of conductivity of the grounding path through the gasket;
FIG. 8 is an electrical schematic diagram to facilitate explanation of the adverse effect on filter effectiveness of poor grounding of a filter capacitor plate through the gasket to the shield can which the present invention minimizes; and
FIG. 9 is an electrical schematic diagram to facilitate function of the inventive structure to minimize the unwanted coupling etfect caused by sharing a common resistor which occurs when the path between two adjacent filter connector contacts is insufficiently conductive.
5 DESCRIPTION OF THE PREFERRED EMBODIMENTS The primary power leads into and out of any equipment enclosures that connect to a power bus must be filtered. Even if not economical, necessity for conserving space may dictate using connectors into and out of the enclosures. It is desirable that the filters be an integral part of the input connector mechanism. Voltage supply leads entering or leaving a module or subchassis enclosure, for example, where a local oscillator, mixer, modulator, or RF amplifier, and high level RF energy circuits are concerned, must be also adequately filtered to minimize the transfer of RF energy from inside the module or subchassis enclosure to other critical circuits external to the subchassis. The filtering requirement applies to all leads including B+ leads, high voltage leads, filament leads and other leads which do not intentionally carry RF signals as well as the signal leads.
In the type of connector to which the invention relates closely spaced connector contact sockets and closely spaced contact pins are required. The present invention provides for this requirement by effectively utilizing integral ferrite loaded filter contact sockets or pins in combination with a critical cooperating retaining, sealing, and grounding gasket. The filter must have the best possible attenuation over a specified frequency range. Fltering only in the primary leads cannot be relied upon. As will become apparent in the light of description hereinbelow, the small bulkhead type feed-through filters along with other decoupling means of the invention and its improved grounding means minimizes the transfer of RF energy from the inside of a chassis enclosure to other critical circuits external to the chassis. The bulkhead mounted filter must be well grounded to preserve the shielding integrity of the enclosure. The inventive combination incorporates feed-through filters with the grounding means which is critical to provide attenuation of a wide range of higher frequencies which should not be passed through the connector. The combination provides the maximum isolation between input and output of the filter and a. minimum inductance path to ground.
Refer to FIGS. 1 and 4. The connector (not numbered) comprises two mating connector sections (not numbered) which are interfitted in mating relationship on the outside and inside of a frame or chassis 26. Frame 26 encloses electronic apparatus (not shown). The electronic apparatus may be computer or communications equipment, for example. Frame 26 is adapted to provide the mounting for the connector by machining or otherwise forming therein a connector body retaining aperture 54 and a pair of bolt, screw, or other mounting hardware retaining apertures 510. In the illustrative embodiment apertures 51c are threaded to receive bolts 27 which are provided. Optionally, apertures 51c may be bored without threads and nuts may be provided to secure the bolts 27.
A connector body 21 molded or otherwise formed of electrical insulating material is provided. Connector body 21 is formed of three generally rectangular parallelepiped shaped sections, a protruding boss section 21a, an intermediate interfitting boss section 21b and a body section 21c.
The body section 210 is the longest section, the intermediate boss section 21b is shorter in length but of the same width as the body section 210 and the protruding boss section 21a is shorter and narrower than the other two sections 21a and 21c. Protruding boss section 210 extends through aperture 54. Intermediate boss section 21b interfits into to fill rectangular aperture 54 in mounting frame 26. Mounting frame 26 is at electrical ground potential.
A deformable conductive gasket 22 formed of rubber or of an elastomer material and impregnated with conductive material and of structure and so combined as to provide a low impedance path to electrical ground potential is provided.
Gasket 22 is of generally rectangular parallelepiped shape and of substantially the same cross-sectional rectangular dimensions as body section 210. The surface around the rectangular edges is herein defined as the edge periphery of the gasket 22. One face of gasket 22 is cemented to the face of body section 210 of connector body 21. The conductive gasket 22 is formed of a yieldable or compressible and relatively flexible material with con ductive material embedded and which is very conductive to certain A.C. noise frequencies under compression.
In gasket 22 is molded or otherwise formed a plurality of closely spaced critically sized relatively small apertures 37 to removably retain filter connector sockets 29 or pin 70 (see FIG. 5) or ordinary connector contact pins or sockets which carry the signal voltage input and out put into and out of the electrical apparatus for which the inventive connector is provided. The filter contact sockets 29 'or pins 70 each comprise a tubular filter disposed along a portion of the contact length. The diameter of apertures 37 is critical with relation to the diameter of the pin or the socket portion contained therein. The apertures 37 diameter is lesser than the contact socket or pin diameters to the extent that the tubular filter of the contact sockets 29 or pins 70 fit into the apertures 37 in an interference fit. However, the difference must not be so great as to cause misalignment of the apertures 37. FIG. 1 illustrates a single filter connector contact socket 29 in position to be inserted into an aperture 37. The gasket 22 material parameters as well as the sizing of its apertures are critical to render gasket 22 suitable for its use in the connector of the invention as will be explained hereinafter in greater detail. Unwanted frequency noise is bypassed through the filter 59 (to be described) of the filter connector contact socket 29 to the conductive gasket 22. It is critical that conductive gasket 22 be of low impedance to provide a good connection through it to ground. The structure and material of gasket 22 required to perform these functions in the connector of the invention is explained in detail hereinafter to facilitate clarity of description in the light of the first following further explanation of the units and elements of the connector.
A hollow rectangular parallelepiped shaped radio frequency interference (RFI) shielding enclosure or shield 23 having an outwardly flanged portion 35 is provided. Shield 23 is formed of metal.
The radio frequency interference (RFI) shield 23 is open on the flanged side and is hollow to define a generally rectangular parallelepiped configuration chamber (not numbered) size and shaped such that together with the mounting frame 26, connector body 21c and the conductive material gasket 22 are enclosed in the chamber by shield 23, the gasket 22 being compressed (transversely) between the underside of the shield upper surface 36 and the adjoining face of the body section 21c of the connector body 21.
As shown in phantom in FIG. 1 the flange 35 of the shield 23 bears upon bearing portion 34 of mounting frame 26. Through the surface 36 (opposite flange 35) of RFI shield 23 is machined or otherwise formed a rectangular shaped aperture 20.
A connector contact support block 24 is provided. Block 24 comprises two substantially rectangular parallelepiped shaped portions, a block body 50 and a reduced length and width block boss 31. Block 24 is formed of nonconductive material. The rectangular boss 31 of block 24 is seated in the rectangular aperture 20 of RFI shielding enclosure 23. The block body 50 of isolation block 24 rests upon the surface 36 and 51 of the shielding can 23.
Connector body 21 is provided with apertures 37a and connector contact support block 24 is provided with apertures 37b, the respective apertures 37, 37a and 37b being aligned for removable insertion of filter connector contact sockets 29 as shown in FIG. 4. Optionally, filter connector contact pins 70 (see FIG. 5) or regular contact pins or sockets could be removably inserted in respective aligned trios of apertures 37, 37a and 37b. The apertures 37, 37a and 37b cover an area bounded by shield aperture 20 to enable free contact insertion and removal. A pair of threaded bolts 27 and pairs of respectively aligned RFI shielding enclosure retaining apertures 51, gasket retaining apertures 51a, and connector body retaining apertures 51b are provided. Bolts 27 are threaded through respective apertures 51, 51a and 51b are threadedly engaged in mounting hardware retaining apertures 510 in frame 26 to retain the shield 23, the deformable conductive gasket 22, and the connector body 21 upon the mounting frame 26 for shielding of the filter connectors 29 and grounding of unwanted signals in a manner to be described. A connector polarizing and securing (or jackscrew) device 25 similar to that described in the aforementioned U.S. Pat. No. 3,281,761 of Moulin is provided. The connector polarizing and securing device 25 comprises a threaded shaft 32 which terminates in a turned or otherwise formed jackscrew boss 32a at one end and at the other end terminates in an aligning and securing boss 60. Aligning and securing boss 60 comprises a plurality of separated keys 52 the separations of which define notches 53. Machined, molded or otherwise provided in connector contact support block 24, deformable conductive gasket 22, and connector body 21 are respective block central aperture 33, conductive gasket central aperture 33a and connector body central aperture 33b. Apertures 33, 33a and 33b are aligned and of diameter to removably retain the connector securing device 25. The central aperture 33 of the connector contact support block 24 is terminated with a block counterbore 80 to form a spanner nut stop shelf 81. The threaded shaft portion 32 and the boss 32a of connector polarizing and securing boss 25 protrudes through the central aperture 33. Spanner nut 28 fits into counterbore 33, and is threadedly engaged upon the threaded shaft portion 32 of connector polarizing and securing device 25 to clamp together the connector contact support block 24, the gasket 22 and the connector body 21. The assembly is tightened to the required securing stress. The keys 52 and notches 53 are mated with the keys and notches of the connector body aligning and securing device (not shown) on the opposite side of the frame 26 to provide proper polarizing (aligning of the respective pins and sockets to be connected to each other).
A mating connector body assembly comprising additional units such as securing device 25, connector body 21, gasket 22, shield 23, support block 24, nut 28 and mounting screws 27 are provided on the opposite side of the mounting frame 26 to complete the connection of signal and power carrying leads into and out of the electrical apparatus. The connector bodies on opposite mounting frame sides are of course complements, for example, since body 21 of the first illustrative embodiment has been boss 21a, the opposite frame side body provided is connector body 57 (see FIGS. 1 and 5) which is formed to have hollow connector body boss receptacle pin protecting portion 56. The contact sockets 29 or contact pins 70 are inserted optionally in either the connector body 21 (shown inside but optionally outside the frame) or the connector body 57, (shown outside but optionally inside the frame) and the mating connector contact pin or socket is secured in the mating connector body 21 or 57 (shown outside but optionally inside the frame) to provide a complete through connection. The connector body 57 with the boss receptacle 56 is more suitable to protect the pins and although interchangeability is contemplated usually this connector body will be utilized for pin insertion and the connector body 21 will be utilized for contact insertion. Usually, also, only one, either the connector contact pin or the connector contact socket is a filter connector contact (provided with a filter) since attenuation may be provided at either end. Optionally, also, a regular connector (not shown) which omits the conductive material gasket 22 may be provided at one or the other side of the frame 26 since filtering need occur at only one point. Although any arrangement can be made, for convenience, usually all the contact sockets 29 are inserted in one of the connector sections and the contact pins 70 in the opposite side connector section. Because of the width of the boss receptacle 56 and boss 21a which fits therein, the flanges (not numbered) of the connector body 57 are spaced from the side of frame 26 opposite the surface 34 side.
Refer again to FIG. 4 in conjunction with FIG. 1.
The basic elements of one of the connector sections may be assembled as follows. The conductive gasket 22. is cemented to the face of the body section 21c of the connector body 21. The connector polarizing and securing device 25 is then inserted into the cemented assembly 21 and 22. The RFI shield 23 is then slipped over the cemented assembly. The connector contact support block 24 is assembled into place so that block central aperture 33 fits over threaded shaft portion 32 of connector polarizing and securing device 25 and block boss 31 of support block 24 fits into rectangular aperture of .RFI shield 23, preventing rotation of block 24 with relation to the assembly. Spanner nut 28 is then secured to threaded shaft 32, completing the connector section assembly. The mechanical advantage of jackscrew for causing a strong connection is achieved without the corresponding disadvantage that unwanted signal bypass through the jackscrew occurs. The aperture 33a of conductive gasket 22 is sized for interference fit therein of connector polarizing and securing (or jackscrew) device 25. The conductive gasket 22 forms a grounding path from the jackscrew 25 to the RFI shield 23 to prevent it from becoming a radiating antenna (at specific wavelengths). Thus in the invention any undesirable signals which would otherwise have passed through the jackscrew 25 are short circuited to ground in addition to unwanted frequencies of the pin connectors being bypassed to ground. The assembled converted section is fastened to mounting frame or chassis 26 with the two mounting hardware threaded bolts 27. Upon fastening bolts 27, a peripheral electrical contact with conductive portion (ground potential) surface 34 is provided the flange 35 of shield 23. Grounding of unwanted noise energy frequencies me. to 10 gc., for example) is facilitated by the action of RFI shield upper surface 36- which applies pressure transversely to deformable conductive gasket 22 when threaded bolts 27 are tightened to draw flange against bearing surface 34 said hence since the depth of shield 23 from the under surface of top wall 36 is less than the thickness in unsecured state of gasket 22 plus body section 210 the inside of upper wall 36 is drawn against and applies pressure on gasket 22. A peripheral electrical bond or contact to the ground potential frame surface 34 is assured by the pressure connection on surface 34 of outer flange 35 of the shielding can 23. Com pletely peripheral contact touching substantially all points is provided by the shielding can 23 upper bearing surface 36 which applies pressure on the elastomeric or rubber gasket 22 when tightened by the mounting bolts 27. The gasket 22 is deformable such that due to the critical dimensions, configuration and securing of elements it hugs the inside of the shielding can 23 and thus assures a completely peripheral contact, that is a level of total ground. Paths of possible RF leakage are minimized or eliminated due to complete shielding by the metallic covering presented by the RFI shielding enclosure 23 and the conductive gasket 22. The closely spaced apertures 37 within the deformable conductive gasket 22 are then filled with filter connector contact sockets 29, or for economy with dummy radio frequency blocking pins (not shown). The dummy pins are formed of brass or other conductive material and are not provided with filters. Alternatively the apertures 37 may be filled with filter connector contact pins 70. The
filter contact sockets 29 (or the filter contact pins 70 when inserted) fit Within the deformable conductive gasket 22 apertures 37 with an interference fit. The resultant pressing of the conductive material around the aperture 37 against the sockets 29 or pins 70 minimizes any chance of radio frequency leakage through the grounding gasket 22 by radio frequency energy propagation down the wire and contact 29 or 70. Since the apertures 37 in rubber or elastomer conductive gasket 22 and the dimensions of the contact sockets 29 (or pins 70) are made such that the contact socket filter outside diameter (at the point touching the gasket) is larger than the diameter of the gasket 22 aperture, an interference fit is provided between the filter contact socket 29 (or the filter contact pin 70) and the gasket material around the aperture. Thus at the point where socket 29 or pin 70 is horizontally resting in the conductive gasket 22 the elastomer material is spread apart by the contact socket 29 or pin 70 and the gasket 22 material is compressed to render the gasket more conductive.
Refer again to FIGS. 1 and 4. The provision of the hood or RFI shielding can 23 configured so as to provide a total shielding and grounding arrangement and with its flange provides (1) a better electrical connection because of the fiat flange portion and (2) added rigidity to prevent the hood 23 or can 23 from mechanical buckling. The contact around the entire periphery at the base of the hood is important for proper grounding of the high-frequency signals involved. The distance between the base of the hood 23 at flange and the inner bearing top surface (not numbered) of the hood is critical to cause the exact amount of compression 'which is required against the top surface of the deformable gasket 22 and at the same time to insure connection of the hood 23 to the chassis 26. This enhances the good electrical connection adjacent to each of the filter capacitor portions 63, the gasket 22, and the grounding hood 23. This feature also causes the gasket 22 material to be under compression both laterally and vertically which is required in order that adequate gasket to shield surface contact to bypass the signals is obtained. This enables a good electrical ground without otherwise required alteration of the physical parameters of the connectors. It also provides filtering out of unwanted frequencies.
Refer to FIG. 6. The expandable nature of the rubber or elastomer 72 around the aperture and the interference fit insure that all parts of the gasket around the aperture and the electode 76 on the filter of the contact pin 70 are in contact. This also minimizes or eliminates any chance of RF leakage through the grounding gasket 72 by RF energy propagation down the contact pin 70 and wire (not numbered). When properly compressed the conductive gasket 22 provides a virtual short circuit to the noise frequencies desired to be grounded. Further, since all parts of the gasket 72 are contacted by the shield 73 interior upon expansion without space permitted therebetween insures optimization of the shielding action.
Refer to FIG. 2. FIG. 2 illustrates the first prepared embodiment filter connector contact 29. The filter connector contact pin 70 of the first preferred embodiment is illustrated in FIG. 4. These filter contact sockets and pins of FIGS. .2 and 4 present modifications of the type of regular contact pins or sockets available in several sizes under Catalog No. M*16Y16CO00, M*20Y2OC000 and M= 22Y22C000 (adding S to the number if a socket and P if a pin) from the Electronic Products Division of the Hughes Aircraft Company, 500 Superior Avenue, Box 1278, Newport Beach, Calif. Tubular contact socket pin receiving portion 67, spring retaining reduced portion 68 and barrel portion 38 are provided. A longitudinal aperture (not shown) is disposed along the central axis of portion 67, 68 and 38 to receive the aligned pin of the mating connector section. At the other end of filter contact socket 29 is a pin crimp barrel 39. A reduced tubular portion 40 is also provided. An aperture adapted to contain a wire lead (22 gauge wire, for example) from a source of electrical power or signal voltage (not shown) is provided and extends along the central axis within the pin crimp barrel 39 and the tubulatr section 40. An inspection aperture 42 is provided. At assembly, a cylindrical contact spring (not shown) is inserted around tubular section 68 for frictional engagement with the contact pin 69 (see FIG. 5) upon insertion through the tubular section 67 of contact socket 29. A pair of contact socket larger diameter bevelled portions 43 and 44 separate a reduced diameter socket section 45 on which is fitted a retaining clip 46. A reduced tubular portion 61 which may retain the pin end, is provided. Alternatively, a wire member could be utilized for the reduced portion 61.
A plurality of ferrite beads 47 are strung over the reduced tubular section 41 and form an inductor of a tubular shaped pi filter 69. A ceramic tube 62 is prepared by applying two separated coatings 64 to its inner circumference to form the inner plates or inner electrodes 64 of two capacitors C1 and C2 and a single outer coating to form the outer plate or the outer electrode 63 of capacitors C1 and C2. These electrode coatings may be applied by painting on the ceramic tube a silver or gold slurry, fired on or baked at about l200 to 1400. The gold slurry may comprise a gold and glass mixture. The tubular pi filter 59 comprises the inductor provided by the ferrite beads 47 and the two capacitors (C1 and C2 of FIG. 3) comprising the common plate formed by the conductive outside electrode 63 of the filter 59 and the opposite or inner plates comprising the inner tube conductive layers or electrodes 64, the dielectric comprising the ceramic tube 62. The electrical configuration is shown in FIG. 3. The resistance of FIG. 3 represents that of the inductor at the frequencies of RF energy considered in the path laterally through the beads 47 from one inner capacitive plate 64 to the other inner capacitor plate 64. The opposing electrode 63 shown in FIG. 3 as two connected together and grounded electrodes is obtained by painting the entire coating over the surface opposite the conductive coating 64. The inner conductive plates 64, the ceramic tubular member 62, and the outer conductive plates 63 thus forms the pair of capacitors C1 and C2 shown in FIG. 3 which together with the inductive reactance or resistance of the ferrite beads forms the pi filter 59. The inductive reactance or the impedance is of the order of 50 ohms at me. frequency. The capacitors C1 and C2 each are about 750 picofared capacitors. The filter 59 may be of the type obtainable from Eric Technical Products, Inc., Ontario, Canada and is illustrated and described on page 19 of its catalog under the designation Erie EMI Filters for Use in Connector Assemblies.
As will be described hereinafter, the filter 59 is grounded through the conductive material filled elastomer or rubber gasket 22 (FIGS. 1 and 3). The assemblage of the filter connector contact socket 29 is completed by applying hard solder to retain the filter tube structure 59 in place. This solder is melted to form solder sections 48 and 49 to make the structure permanent. A dielectric insulating coating 56 such as an epoxy paint is provided covering the outside portions of electrode 63, the solder sections 48 and 49, a portion of reduced tubular section 61 and the tubular section 41 adjacent to reduced tubular portion 40. Thus, just the center (gold) coating or plated portion of filter outer electrode 63 is exposed and is connected to the conductive gasket 22 which forms a grounding path from this capacitor plate 63. The painting of the dielectric epoxy 56 on both of the edges permits conduction from the conductive surface 63 into the conductive gasket 22, yet prevents shorting of the high voltage from the pin portion which might otherwise occur because of particles of conductive gasket material or along the conductive material of the gasket. This feature of providing the dielectric along the edges and over the solder portions 11 48 and 49 thus prevents the signal or voltage from being shorted out.
Refer to FIGS. and 6. These figures illustrate a preferred connector section wherein a filter connector contact pin 70 instead of a socket 29 is provided. The pin 70 Structure is similar to that of the contact socket 29 hereinabove described and the tubular filter 97 provided for the pin 70 is identical. Further description of the pin 70 and its tubular filter details which are the same as or apparent from the socket is therefore not provided. A crimp pin end barrel (not shownsurrounding lead 77) and a contact pin portion 69 are provided. A wire (not shown) which forms the connection to the lead 77 is inserted into the open end of the pin crimp barrel and the assemblage is then crimped, for example, in four places. The crimpbarrel of the pin 70 is placed adjacent to the hard solder as in the above operation for the filter socket 29. Before the soldering operation the wire inserting operation is completed so that when the hard solder is reduced the solder runs into and fills in the pin space to insure a good electrical as well as mechanical contact. As in the case of the contact filter 59 the painting material is a silver or gold slurry which is fired on or baked on to form a coating at about 1200" to 1400. The gold slurry comprises a gold and glass mixture comprising about 80-90 percent of gold. After the solder is placed adjacent to the ends of the assembly, the crimp barrel (not shown) is put on and the unit assembled in an oven at about 361 F or higher to about 400 In this manner, solder flows along the pin contact 70 and makes a good mechanical and electrical connection and the solder also makes a good connection with the inner electrode 64 of the ceramic tube filter 59. Optionally, of course, any of several conventional methods of assembly of the wire in crimp barrel for 77 may be employed, for example, other methods include solder cup assembly wherein crimp barrel is diagonally cut to provide an open cup configuration for soldering, etc.
As indicated hereina-bove the material and parameters of gasket 22 are critical. Gasket material which has some of the characteristics and parameters for the purposes of the invention is described in aforementioned US. Pat. Nos. 3,140,342, 3,194,860 and 3,202,488 and the disclosure of these patents is referenced herein to broadly illustrate the manufacture and composition of material for gasket 22. However, such gasket material requires critical changes and modifications to be suitable for invention. Conductive rubber and other elastomeric materials of the required characteristics may be used as the basic material. The gasket 22 must be of suitable softness, conductivity when deformed by the contacts and shield, thickness and configuration and the apertures must be of proper size of interference fit without misalignment occurring.
The gasket 22 material may comprise, for example, a conductive synthetic or natural rubber which is made conductive by impregnating therein conductive material. For example, an RTV (room temperature vulcanizing) rubber may be made conductive by impregnating therein silver balls of the greatest possible number to lend conductivity. This may be, for example, from 78 to 92 percent composition of silver balls by weight. Such materials include, for example, rubber materials manufactured by the Ablestick Company of Gardena, Calif. identified as HP16128, RTV 731 Silicone or adhesive silicone rubber MIS13,968; a rubber material sold by the Dow Corning Corp. and identified as RTV3140. Alternatively a synthetic rubber such as Neoprene, Viton, or Hypalon may be utilized. Still further, alternatively, silicone elastomers, urethane elastomers, flexible epoxy, vinyl plastisols may be employed. For connector use, the conductive rubber or other flexible conductive material must be corrosion resistant. Therefore, if a rubber material is selected, the rubber must be noncorrosive,
that is, the rubber must give off alcohol when cured rather than acetic acid so as to solve the corrosion problem. This is accomplished by selecting a rubber which can be cured by catalyzing with stannous octoate dibutyl tin dilaurate. Such material when selected must comprise at least 75 percent to 92 percent by weight of conductive filler such as silver, copper, or plated copper balls to 25 percent of the RTV3140. The so-called conductive elastomers or rubbers of the above-mentioned patents and their process are unsuitable. They do not provide the required conductivity and as taught by the invention additional conductive filler should be employed to provide a low resistance path to ground at the proper frequencies and the elastomer rubber or synthetic rubber must be made more conductive by impregnating a larger number of metal balls or other conductive materials. The filler must be sufficient for the critical conductivity required when the gasket 22 is compressed. The gasket material is not sufficiently conductive to ground noise frequencies without required compression by the contacts and shield. The degree of softness of the rubber or elastomer material which is required to provide compressibility and grounding through the balls or other conductive material when the apertures are made of proper diameter with relation to the diameter of the contact pins or contact sockets must be provided.
In conjunction with the softness (or hardness) of the elastomer or rubber material of the gasket 22, the dimensions of gasket 22 in the configuration is critical. The compression effected both in the transverse direction along the pins and the lateral direction must provide good conductivity. The aperture size, flexibility, and gasket layer thickness are also critical. The aperture size must be such as to provide an interference fit with the contacts such that both transverse and lateral compression results. However, the deformable gasket 22 must not be laterally displaced so as to cause substantial misalignment of the apertures in which the contact sockets 29 or pins 70 fit. Aperture sizes of about .030 to .040 inch with a pin outside diameter of .063, for example, are satisfactory.
In the illustrative embodiment maximum attenuation of RF noise over the frequency range of 30 ml-Iz. to 10 gHz. must be attained and at least a to decibels attenuation is desirable. To attenuate signals above 30 me. representing unwanted noise frequencies, the connector contacts must be of size and configuration in conjunction with the gasket 22 apertures 37 and must be emplaced to exert pressure against the conductive material in the gasket 22 such that grounding of the unwanted signals is assured. Additionally, the structure must be flexible to avoid damage to the fragile tiny contacts. Thus, the size of the apertures in the gasket is critical because when the connector contact sockets 29 or pins are emplaced through the apertures 37 the connectors must apply force to the silver balls or other conductive material in the gasket such that contact ground (that is to the chassis) is assured so that return line feedback is obtained. However, the apertures must not be so undersized as to make it virtually impossible to remove the contacts without breaking them or to permanently embed the connector filter contact pin 70 or filter connector contact socket 29 into the gasket 22 or 72.
Refer to FIGS. 6 and 7. The conductive filled deformable material of gasket 22 must be crimped or puckered for the required low resistance effect to take place. This pucker 72a is established by the gasket material 72 being sufliciently soft when the critical relationship between the aperture 76 diameter size into which the filter connector contact pin 70 fits and the contact pin 70 tubular filter outside diameter size is provided. The aperture 76 must be smaller than the outside diameter of the filter 76. Additionally, the largest pin 7 0 outside diameter and connector body 74- apertures must be of diameter sizes such that the pin 70 clears the connector body 74 aperture in a lose fit so that damage to the outside of the filter does not occur while the filter diameter must be such that as much compression as possible of the conductive material gasket 72 occurs.
It is important that the connector contact sockets 29 and pins 70 be removable. For this reason, retaining clip member 46 and the corresponding structure of reduced sleeve 45, bevelled stop portions 43 and 44 and the other portions of the contact sockets 29 and pins 7-0 are of configuration a'nd size in conjunction with the aperture size of the connector body 21 apertures 37a the connector contact support apertures 37b and block 24 the gasket apertures 37 (and corresponding apertures in the FIG. 5 and 6 connector section) such that room is provided between the socket 29 or pin 70 and aperture 37a and a tool (not shown) required to compress the flaring portion 66 of retaining clip 46 back from stop shoulder 43 into double bevelled aperture 65 (or corresponding elements of clip 96 into connector body double bevelled aperture 79 of pin 70 connector section assembly of FIG. 5) for disassembly of the connector socket 29 or connector pin 70. For this reason a loose connection is required with room for the tool betwen the connector body 21 aperture 37a and the filter connector contact socket 29 or pin 70 peripheral surface.
The gasket 22 is provided with apertures 37 which are smaller in diameter than the filter 59, 76 or 97 diameter but since the gasket is yieldingly deformable filter 59, 76 or 97 is not hurt on being inserted through the aperture 37. This diameter size relationship between the filters peripheral surfaces and the gasket apertures causes a tight interference yet flexible fit of the filter to engage the gasket walls of the gasket apertures to provide not only electrical connection of the filter capacitor outer electrode 63 to ground in order to attenuate the high frequency noise or unwanted signals, but it also provides a yieldable but firm support for the otherwise loosely fitting socket 29 or pin 70 which prevents damage to the socket 29 or pin 70. The socket 29 or pins 70 is of dimensions such that by itself it is extremely fragile. However, because of the resiliency, springiness, flexibility, suppleness and elasticity material of the deformable conductive gasket 22 the pin 70 or socket 29 is held firmly in place. In addition to being held firmly, the pin 70 or socket 29 is held yieldably so that any shocks will be absorbed by the springy and resilient material of the gasket 22 and yet permit removal. This feature of providing a good electrical contact and yet permitting removal of the pin 70 or socket 29 without loss of pin or socket density is an important feature of the present invention. It is often a requirement that a certain amount of connectors per square inch must be provided in the space allotted. Further, the connection of the pins must not be permanent but the pins and contacts must be removable for replacement or other reasons. By utilizing the conductive material impregnated rubber or elastomer material gasket 22 of suitable softness, and an adequate number of conductive balls (conductive materials), the advantages are obtained of good electrical connection, vibration damping and substantially eliminating need for some close machine tolerances and dimensions. Close tolerances are provided on the outside diameter of the filter contact pin 70 or socket 29 with respect to the connector body 21 aperture 37a such that the filter connector socket 29 or pin 70 will be closely fitting yet enable a tool to be pushed therearound for disassembly and assembly purposes without appreciably affecting the physical characteristics of the pin 70 or contact 29. However, the tolerance with respect to the rubber conductive gasket 22 is much less critical. This permits temperature variation and variation in manufacturing of the pins and the rubber gaskets (thicknesswise but not aperture-wise). The compression of the rubber or elastomer material of gasket 22 by the adjacent filter capacitor plate 63 facilitates the electrical bypassing of high-frequency unwanted signals to ground and also prevents RF energy from traveling along the outside of the socket 29 or pin 70 into the enclosure to which connection is to be made.
Refer to FIG. 8. As apparent from that schematic representation where the path to ground is not sufficiently conductive, the impedance Z1 of the rubber causes coupling of the unwanted signals into the enclosure rather than bypassing the high-frequency unwanted signals to ground.
Refer to FIGS. 6 and 7. The insertion of the pins 70 (or contact sockets 29) into the gasket 22 aperture 37 provides puckering as exemplified by insertion of two pins 70 which causes there to be a puckering 72a and :very low impedance between adjacent pins 7 0.
The puckering of the deformable gasket material illustrated in FIG. 7 by the phantom lines 72a causes a very low impedance between adjacent sockets 29 or pins 70.
Refer to FIG. 9. With relatively high impedance Z2 between the pins there exists a commonly shared impedance which causes coupling of the signals between sockets 29 or pins 70. The tuned circuits in FIG. 9 represents thecharacteristics of pairs of sockets 29 or pins 70. The lowering of the resistance or impedance 21 by the puckering of the deformable gasket material (FIG. 8) avoids unwanted coupling of the different signals or voltage carried by ditferent pins 70 (or sockets 29). This effectively eliminates cross-talk by providing a very low resistance between the pins yet avoiding actual contact. The invention is therefore applicable to small closely spaced pins 70 (or contacts 29). Without the high conductance of the conductive gasket as combined in the invention an unwanted inductance and therefore coupling and cross-talk between two connector pins would occur.
Refer to FIGS. 1 and 5. Connector body 57 which contains pins 70 has an upstanding rectagunlar tubular boss portion 56 hollowed out to provide protection for the pin ends 69 and is dimensioned to fit in closely mating relationship over the protruding boss section 21a of connector body 21. This interfitting also causes the pins 70 to align themselves with the respective sockets so that a good connection between all of the contact pins 70 and contact sockets 29 is maintained. A nonconductive interfacial seal 71 is provided and enclosingly covers the pin containing body member 57 to prevent moisture and other ambient contaminating conditions from adversely alfecting the transmission of signal and power voltages. The remaining elements of the pin retaining connector section comprise an elastomer or rubber conductive section 92, a connector contact support block 84, and a shield 93.
As in the case of the filter connector contact socket 29, the gasket 92 is of conductive elastomer material filled with a conductive filler, the connector body 57 is of nonconductive dielectric material and the connector pin support block 94 is of nonconductive dielectric material. Corresponding to socket filter 59, a pin filter 97, the bak ing on step of which has been described hereinabove, is provided. A pin retaining clip 96 is provided for each pin 70 and is configured to permit insertion into the apertures (not numbered) of block 94, gasket 92, connector body 57 connector and seal 71 and removal by assembly tools as in the case of the contact socket retaining clip 46 as Will be described hereinafter.
Refer to FIGS. 4 and 5. The uncoated portion of the outer electrode 63 of the socket filter capacitor is in continuous direct contact around its periphery with the elastomer or rubber conductive gasket 22 and extends partially into the connector contact support block 24 and the filter connector body 21. The dielectric coating 56 on the ends of the socket filter and the remainder of the contact socket extends through adjacent portions of the connector body 21 and the block 24. Similarly the filter contact pin, conductive electrode uncoated portion of the outer electrode of the filter capacitor (not numbered) is in continuous direct contact around its periphery with the elastomer or rubber conductive gasket 92, and extends partially into the connector contact support block 94 and the connector body 57. The dielectric coating on the pin filter (not numbered) and the remainder of the contact pin extends through adjacent portions of the connector body 57 and the block 94.
Each of the connector socket retaining apertures 37a in the connector body 21 (and each of the pin retaining apertures in the corresponding connector body 57) comprises a smaller diameter aperture 65 (or connector body 57 smaller diameter aperture 79) chamfered at both ends into which the retaining clip 46 (retaining clip 96 for the pin) in disposed, the chamfered aperture ends forming two beveled shoulders between which the retaining clip 46 is retained around the contact socket reduced diameter portion 45 (retaining clip 96 around reduced diameter portion 75 for the pin 57) to retain the filter connector contact sockets 29 (or connector contact pins in the opposite connector) in fixed position in respective aligned apertures 37b, 37 and 37a.
One of the features of the connector of the invention is that the filter connector contact sockets 29 and pins 70 are readily insertable and removable. A contact socket 29 is inserted by first inserting the pin receiving portion 67 through successive apertures 37b, 37 and 37a. The connector apertures 37b of the connector support block 24, and the portion of aperture 37a of the connector body 21 nearest the gasket 22 are of greater diameter than the socket 29 or pin 70 largest outside diameter to permit insertion therethrough. The portions of the socket 29, inserted first, tubular contact socket portion 67, tubular reduced contact socket portion 68 which contains a contact spring therearound and tubular contact socket sleeve portion 38 are of lesser diameter than the reduced diameter double beveled aperture 65 within connector body 21. The connector apertures 65 may be each formed by mold ing or otherwise forming a counterbore at each end of the connector aperture which terminates in a beveled rear portion and a space between the two apertures defines the reduced diameter double beveled aperture 65.
Upon insertion, at the connector body 21 end a tool having a front sleeve end which resembles a leadless mechanical pencil, and which advances in peripheral surrounding relationship around successive tubular contact socket portions 67, 68 and 38 may be provided and facilitate pushing of the open slot end 66 of retaining clip 46 and hence the retaining clip 46 into the space between the beveled surface of the reduced diameter aperture 65 and the reduced diameter socket section 45 to permit insertion of the contact pin. Upon release of the tool member, the flaring flange 66 of the spring retaining clip means 46 will spring into place surrounding adjoining chamfered contact socket portion 43 and movement of the contact socket (retaining clip 96 similarly locks the contact pin in place in the contact pin retaining connector section) in either direction will be prevented. In this condition the reduced tubular portion 61 and a portion of the outer filter capacitor surface covered by the dielectric paint 56 is within the connector body 21 and the conductive surface of the outer electrode 63 of the filter capacitors 61 and 62 is held in interference fit relationship in the aperture 37 of deformable conductive gasket 22. The last to enter portion of the tubular filter 63, which is surfaced with dielectric paint 56, including dielectric surfacing over the solder 48, is retained in the connector support block 24. The dielectric coating material guards against shorting of the signal or power high voltage from the contact socket to ground along the rubber or elastomer conductive gasket 22. In assembled condition, the crimp barrel 39 and reduced tubular portion are also contained in the connector block body 24 aperture and embedded slightly from the outer block 24 surface. The tubular contact socket pin receiving portion 67 is also embedded slightly below the Cir end face of the connector body 21 when in assembled condition.
Refer to FIG. 4. Outer electrode 64 on the filter contact socket 29 makes a physical and electrical contact with the grounding gasket 22 necessary for the pi filter network. The retainer clip 46 retains the contact 29 within the molded connector body 21 by a jam type feature as described hereinabove. It will be understood, of course, that other types of retention means than the jam type illustrated might also be introduced without departing from the principles of the invention.
Removal of the contact socket 29 (or pin 70) is effected by means of a simple extraction tool (not shown). The tool comprises a right cylindrical sleeve which fits around the the tubular pin receiving and sleeve portions 67 and 38 and which compreses the flange 66 of spring retainer 46 such that it is withdrawn into the space around the reduced diameter socket section 45. The tool further comprises a central retractible and insertable pin which pushes the contact socket 29 (or pin 70) through the reduced aperture and the socket 29 (or pin may be readily withdrawn through the apertures 37 and 37b to be removed. Thus the contact socket 29 (or contact pin 70) can be removed for rewiring or replacement. Together with seal 71 and of itself, deformable gasket 22 provides a sealing feature against harmful environment such as ambient moisture. The dielectric coating 56 prevents shorting by contamination or by conductive particles. Because of the high resistance afforded by the dielectric 56, increased reliability is obtained and the possible electrical creepage path of B+ voltage to ground is increased. This provides improved high voltage breakdown characteristics and insulation resistance.
It should be understood that a filter connector section is not normally used with a filter plug connector section where the attenuation, which would be the end result normally, is not needed. A standard nonfilter mating connector section is therefore normally used.
Thus, the illustrative embodiment of the present invention illustrates a connector combination including filter, shielding, isolation, and grounding means which provide maximum attenuation of RF over a desired frequency range, for example, the frequency range of 30 mHz. (megahertz) to 10 gHz. (gigahertz). For this purpose the invention provides means wherein a filter (which may be a pi filter) incorporated within the connector socket or pin structure has a capacitor plate of the (pi) filter connected to reference voltage (ground) via a low impedance path. The filter may, for example, be tubular and fit over a portion of the socket or pin and the grounded capacitor plate may be a common external plate opposite two internally disposed plates of the tubular pi filter. The low impedance path may comprise a gasket. The gasket of the invention is so structured that it possesses the required minimum coupling between physically adjacent filters as well as providing the low impedance path to ground. The gasket may be rubber or elastorner material. To obtain the minimum impedance of the gasket, the gasket material (which may be of rubber or elastomer material filled with conductive particles and apertured to receive contacts or pins) is made deformable and is pressured by its enclosure and by contacts inserted in the gasket apertures. The pressure on the gasket of the inventive combination provides physi-.
cal contact of the conductive particles which may be, for example, silver plated spheres suspended in the rubber or elastomeric gasket material and it insures adequate physical contact, and thereby electrical contact, between the conductive material embedded in the gasket and the filter capacitor plate and a low resistance path between such contact and the reference ground plane (the shield and frame).
While the principles of the invention have now been made clear, where will be immediately obvious to those skilled in the art many modifications in structure, ar-
rangement, propositions, and elements and components used in the practice of the invention, and otherwise, which are particularly adapted for specific environments and operating requirements without departing from those principles. While salient features have been illustrated and described with respect to particular embodiments, it should be readily apparent that modifications can be made within the spirit and scope of the invention, and it is therefore not desired to limit the invention to the exact details shown and described.
What is claimed is:
1. An electrical connecting means comprising:
(a) a deformable gasket having an edge periphery and structured and formed of a composite of materials comprising conductive materials such that said gasket provides enhanced conductivity to a predetermined range Of frequencies of A.C. signals under compression, said gasket having at least one aperture,
(b) at least one connector contact having a portion retained in said at least one aperture,
(c) said at least one contact and said at least one aperture being relatively configured and sized such that said portion of said at least one contact is retained in contactingly fitting relationship so that said range of A.C. signals are conducted through said gasket, and
(d) grounding means totally surrounding said edge periphery of said gasket in pressurizing contact such that said gasket is compressed between said edge periphery and said contact and thereby provides said enhanced conductivity.
2. The electrical connecting means of claim 1 wherein:
(a) said at least one aperture and said at least one contact further comprises a plurality of apertures and a plurality of contacts each having a portion retained in one of said plurality of apertures,. each of said portions of said contacts comprises an integral filter means, and
(b) said contacts are positioned with relation to said gasket apertures such that said filter means contact the gasket walls defining said apertures.
3. The electrical connecting means of claim 2 wherein:
(a) said filter means and said apertures are of relative size such that the filter means fit into said gasket means in interference fitting realtionship to apply pressure to said gasket, and
(b) said deformable gasket is of configuration, thickness, sizing and conducting material contained structure such that it has increased conductivity under gasket compressing pressure applied by said con- 5. The electrical connecting means of claim 4 wherein:
(a) said shield comprises a flanged peripherally surrounding member configured to define a chamber of lesser depth than the height of said gasket,
(b) means having a surface at electrical ground potential,
(c) securing means operative in conjunction with said flange such that said gasket contacts said ground potential surface inside of said chamber under pressure in the direction of the longitudinal axis of said contacts, and
(d) said deformable gasket comprises a deformable material impregnated with a conductive filler such that said pressure applied by said shield and said contacts increases the conductivity of the gasket.
6. The electrical connector of claim 1 wherein said gasket is of noncorrosive cured rubber material and wherein said conductive material filler is of sufficient amount such that under deforming pressure it is conductive to signals of unwanted noise frequencies so as to ground out a high percentage of said noise frequency signals.
7. The electrical connector of claim 1 wherein said gasket apertures and contacts are relatively sized such that said gasket is deformed by said contacts applying pressure against the sides of the gasket apertures in which said contacts are retained, and said conductive filler comprises conductive material filler of sufiicient amount such that said deforming of said gasket renders it highly conductive to a range of frequencies from about thirty megacycles to over a gigahertz.
8. An electrical connector comprising:
(a) a plurality of connector contacts,
(b) said contacts comprising integral filters,
(c) a deformable gasket member having apertures disposed therethrough and sized with relation to said filters such that said contacts are removably retained with each said integral filter abutting the periphery of one of said gasket apertures,
(d) shielding enclosure means enclosing said deformable gasket to provide shielding from RF energy,
(c) said gasket further comprising conductive material filler and being disposed in connecting relationship between said shielding enclosure means and said filters so as to ground signals bypassed by said filters.
9. The electrical connector of claim 8 including:
(a) a nonconductive connector body,
(b) said connector body having apertures therein aligned with said gasket apertures and configured to removably retain said contacts in freely passing in and out relationship, and
(c) retaining means operative in conjunction with said retaining configuration and said contacts whereby said contact is removably retained in temporary fixed position in said body and within said electrical connector.
10. The electrical connector of claim 9 wherein:
(a) said connector filters are tubular in shape,
(b) the apertures in said deformable conductive gasket are of critical size to receive in interference fitting relationship said tubular filters such that said tubular filters closely hug the sides of and deform the gasket maiterial surrounding each of said gasket apertures, an
(c) said gaskets are of material such that when deformed by said connectors they form a low conductive path to predetermined noise frequencies passed by said filters.
11. The electrical connector of claim 10 including:
(a) a connector polarizing and securing device, and
(b) said connector body, said gasket, and said shielding enclosure means each further comprise a polarizing and securing device receiving aperture,
(c) said polarizing and securing device, comprising means to secure said electrical connector together,
(d) said conductive gasket device securing aperture being of diameter with relation to the diameter of said device to engagingly connect said securing device to said shielding enclosure means whereby radio frequency noise energy which would otherwise go through said polarizing and securing device is bypassed to ground via said conductive gasket and prevents said device from becoming a radiating antenna.
12. The electrical connector of claim 8 including:
(a) a pair of securing means whereby said shielding enclosure means is secured,
(b) said shielding enclosure means further comprising a depending peripheral flange,
(c) said flange being apertured and said securing means being received in said flange aperture,
((1) a frame at electrical ground potential,
(e) said depending flange contacting said frame in closely bearing relationship,
(f) said frame being apertured, said securing means being retained in said frame aperture and securing said shielding enclosure means to said frame,
(g) said connector body and said gasket being dimensioned with respect to the thickness of the interior of said shielding enclosure means such that said shielding enclosure means compresses said deformable gasket to provide a good radio frequency ground.
13. An electrical connector to provide radio frequency shielding and prevent propagation of unwanted noise into electronics equipment having a frame at electrical ground comprising:
(a) a pair of mating connector sections oppositely mountable on said electronics equipment frame,
(b) at least one of said connector sections comprising a connector body and a deformable conductive gasket,
(c) said body and said gasket being aligned and each having a plurality of apertures, said body and gasket apertures being aligned,
(d) a plurality of filter connector contacts disposed in said aligned apertures,
(e) a shielding enclosure of conductive material surrounding the periphery of said body and said gasket and configured inside to interfit over the body and gasket in closely interfitting relationship,
(f) means to secure said shielding enclosure to said frame,
(g) said inside of said enclosure being sized such that said securing means in conjunction with said enclosure form means to apply pressure to said gasket,
(h) said connector body apertures being formed of larger size diameters than the diameters of said connector contacts, the size relationship being made such that a connector contact removing tool may be inserted around said contacts and fit within said body apertures,
(i) said gasket apertures being formed of lesser size diameters than the maximum diameters of said connector contacts,
(j) said filter connector contacts each comprising. a fi ter means having an electrode in engagement with an aperture of said gasket,
(k) said gasket apertures being critically sized for below impairing pressure upon but removable retention of said contacts so as to enable deformation of said gasket by said contacts, and
(1) said gasket being formed and of material such that pressure of the retained filter contacts upon the gasket and pressure of the shielding enclosure upon the gasket cause transverse and lateral distortion such that the gasket conductivity is assured and a very low resistance path is provided from said filter electrodes through said gasket to said enclosure.
14. The electrical connector of claim 13 wherein:
(a) said deformable conductive gasket, and said shielding enclosure are of mating configuration such that said conductive gasket is electrically contacted by said shielding enclosure around substantially 360 periphery of said gasket, and
(b) said shielding enclosure further comprising a depending fiange to ground said shield to said frame substantially around the periphery of said shield and to lend structural strength to said shield to enhance its capability of compressing said deformable gasket.
15. The apparatus of claim 14 wherein:
(a) said connector body comprises first, second, and
third boss sections,
(b) said frame is apertured to receive said second connector body boss section, such that said third body section protrudes therethrough and said first body element rests upon said frame,
'(c) said gasket is of substantially the configuration and size of said third body section,
'(d) said shielding enclosure, gasket and third body section is of size and configuration such that said third body section and said gasket are retained in closely interfitting engagement into said shielding enclosure,
(e) said shielding enclosure is of thickness so as to compress said deformable conductive gasket member against said third body section,
(f) means to secure said shielding enclosures to said frame so as to cause compression in a longitudinal direction across said deformable conductive gasket,
(g) said gasket aperture being preformed and undersized critically such that the compression of said filter element of each of said connector contacts causes deforming of said deformable conductive gasket to enhance conductivity such that a substantially minimum resistance path is established between said contacts and from the filter of each of said contacts to said shielding enclosure.
16. An electrical connector providing radio frequency shielding and preventing propagation of unwanted noise into electronics equipment comprising:
(a) a connector body means adapted to be secured to the electronics equipment and having a plurality of closely spaced apertures longitudinally disposed therethrough,
(b) a gasket of deformable and resilient non-conductive material filled with conductive material such that under compression a low resistance path across said gasket is provided, and having a plurality of apertures aligned respectively with said connector body apertures,
(c) a shield surrounding the periphery of said gasket and connector body,
(d) means securing said shield to said equipment, said shield being of dimensions and configuration such that it effects longitudinal and transverse compression of said gasket member to assure the gasket conductivity,
(e) a plurality of tubular shaped relatively small connector contacts each movably secured into one of the aligned apertures of said gasket and said connector body,
(f) each of said connector contacts comprising a tubular filter member, each said filter member comprising an inductor and a capacitor having inner and outer electrodes, each said filter being disposed around one of said contacts and positioned so as to extend through one of said gasket apertures, each said tubular filter member having the outer electrode of the filter capacitor disposed therearound,
(g) the diameter relationship between said gasket apertures and said filter capacitor outer electrode being such that an interference fit therebetween results to cause deformation of said deformable gasket along its transverse and lateral dimensions so as to provide a very low conductive path from said filter capacitor through said gasket,
(h) said conductive gasket further comprising a conductive path between said means to connect said conductor body and said gasket and also comprising blocking material around said contacts to thereby provide a grounding path for and prevent unwanted radio frequency energy from traversing said connecting means.
17. The electrical connector of claim 16, wherein:
(a) said connector body defines apertures comprising a counterbore portion at each end and an interiorly disposed smaller bore section having a bevelled shoulder at each end,
\(b) retaining clip means surrounding each said contact in said smaller bore section in assembled relationship of said contact into said connector body,
(c) said retaining clip means comprising flared fiange means retaining said contact in position in assembled relationship, said flared fiange means being compressible into said smaller bore section to permit removal of said contact,
(d) said contacts comprising selectively contact sockets or contact pins of configuration to optionally fit in said connector body and gasket apertures.
18. The electrical connector of claim 16 wherein:
(a) said deformable material is formed of soft rubber cured to avoid giving off of corrosive material and impregnated With a substantially maximum Weight of conductive material sufficient to render the deformable material conductive under pressure substantially to a short circuit impedance to frequencies of electrical energy desired to be by-passed to ground.
19. The electrical connector of claim 16 wherein:
(a) said gasket aperture diameter is in the approximate range from one-half to two-thirds of the diameter of said connector contact at the area of interfitting of said contact into said gasket aperture.
20. A connector comprising:
(a) a connector body having first, second and third boss members,
(b) a frame to housean electrical equipment, said frame having an aperture therethrough sized and shaped such that said second connector body boss member is closely received in said aperture and said third connector body boss member is positioned in relationship such that it protrudes therethrough and said first connector body boss member has a surface resting upon said frame,
(c) a gasket conductive to unwanted A.C. frequency energy and of substantially the size and shape of said third connector body boss member,
(d) a shielding can of configuration and size such that it fits closely around said conductive gasket and said connector body,
(e) said conductive gasket being formed of basic material selected from the group comprising (1) noncorrosive cured rubber to avoid giving off acetic acid, (2) synthetic rubber and (3) elastomer material, said basic material being impregnated with highly conductive material, said gasket being compressed to become more conductive,
(f) said connector body having apertures and said gasket member having apertures aligned with respective members of said gasket,
(g) a plurality of tubular shaped connector contacts, each of said connector contacts further comprising a tubular filter having an external capacitor plate and a contact portion respectively positioned in said aligned apertures of said gasket and said connector body,
(h) each of said gasket apertures being of lesser diameter than the diameter of its said connector contact filter external capacitor plate and receiving its said external capacitor plate in interference fitting surrounding relationship such that said gasket is deformed,
(i) said connected body apertures being larger than the diameters of the portions of said contacts positioned therein to permit insertion of a removing tool around said contacts,
(j) spring retaining clip means yieldingly but removably seating said contacts in fixed transverse connector body aperture retained position,
(k) the sizing of said tubular filter outside capacitor plates and said gasket apertures being critical such that said gasket is deformed to provide a low resistance path to high frequency noise to said shielding means, and
(1) said shielding can having a flange adapted to bear around its periphery against said frame and to render said shielding means rigid.
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