US 3718887 A
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Description (OCR text may contain errors)
Feb. 27, 1973 w. E. SOLOMON ETAL 3-7131387 CONNECTOR 3 Sheets-Sheet 1 Filed June L4, 1971 0 Q Q Q I Q Q w miwQ Q Q Q Q Q Q Q Q Q lllll m i w. E. SOLOMON ETAL 3,713,337
Feb. 27, 1973 CONNECTOR 3 Sheets-$heet 2 Filed June L4, 1971 OOOOOOOOOCOOO OOZIIIIIIIOO OOO::::::OOOO
Feb. 27, 1973 w, SOLOMON ETAL 3,718,887
CONNECTOR 3 Sheets-Sheet '5 Filed June 14, 1971 United States Patent Oflice 3,718,887 Patent-ed Feb. 27, 1973 Mass.
Filed June 14, 1971, Ser. No. 152,669
Int. Cl. H01r 13/40 U.S. Cl. 339-92 M 17 Claims ABSTRACT OF THE DISCLOSURE An electrical connector has a housing formed of radio frequency interference shielding. A plural lead, shielded cable is joined to the housing with an end passing therein. Leads of the cable are joined to individual connector pins located at a connection end of the housing. Premolded insulating fillers are used to fill some of the space within the housing in conjunction with in situ molded insulating material. The connector pins are preferably mounted on a terminal board with locking means for preventing disarray of the connector pins during in situ molding and thereafter. A strain relief member is preferably molded over the cable and housing for strain relief and environmental control. Preferably jack screw means are fixed in position for rotation within the housing to secure the connector to an attached terminal board or similar mating connector.
BACKGROUND OF THE INVENTION Radio frequency interference, i.e., R.F. interference, has become a problem particularly with sophisticated computers and in other devices. It is known that R.F. shielding can be used to prevent stray currents, voltages and signals from interfering with apparatus external to connectors or vice versa. Radio frequency interference is a particular problem where wires carry low magnitude signals which can pick up air signals and cause distortion such as unwanted activation of bits in the memory system of a computer. It has been a problem to obtain plural terminal connectors which provide good R.F. shielding, are compact, easily fabricated and simply constructed.
Another problem in the connector art arises when in situ molding of insulated material is used. When plural contact pins are used and have ends exposed to the in situ molding operation, the pins tend to be pushed out of predetermined alignment by the molding material.
SUMMARY OF THE INVENTION It is an object of this invention to provide an electrical connector for multi-lead cable, which connector has good radio frequency interference shielding properties.
Another object of this invention is to provide a con nector in accordance with the preceding object which can be easily assembled with good mechanical properties.
Still another object of this invention is to provide an electrical connector in accordance with the preceding objects which provides for positive engagement of the connector with a device to be connected.
Still another object of this invention is to provide a terminal board for an electrical connector which terminal board carries a series of contact pins locked in a predetermined array by a novel locking means.
According to the invention, an electrical connector has a connection end formed by housing walls opened at the connection end. The housing has radio frequency shielding properties on all walls thereof. An electrical cable has an end passing into the housing with the cable carrying a plurality of insulated electrical wires or leads and a surrounding R.F. shield. Means are provided for locking an end of the cable in the housing preferably with mechanical engagement of the cable with the housing. A plurality of contact pins, each having an inner end connected with a selected one of the leads and an outer end for connection with another device, are mounted on a contact pin terminal board which defines a first inner surface and a second outer surface. The terminal board is positioned between the inner and outer ends of the contact pins to locate the pins in a predetermined array.
Preferably locking means are interconnected with a plurality of the contact pins and bear against a surface of the terminal board to prevent unwanted movement of the pins from the predetermined array.
Preferably jack screw means pass through the housing without detracting from RJF. shielding properties of the housing for tightly engaging the enclosed housing with a mating connector which may be another similar mating cable end or a terminal board of a device such as a computer chassis.
In the preferred embodiment, a thin molded-on strain relief is provided over both the housing and a portion of the cable joined to the housing.
It is a feature of this invention that the housing itself forms an enclosing R.F. interference shield and can be electrically engaged with the shield of the cable. The assembly of the electrical connector is simply to carry out and provides compact, rugged, multi-lead devices which provide for predetermined arrays of for example from 25 to over contact pins. The novel and improved terminal board and locking means, which can be used in other connector devices, provides for positive positioning of the contact pins in an efficient assembly operation.
Preferably the housing has a portion thereof filled with a premolded filler or insulating collar and the remainder thereof filled with an in situ molded insulating material. Use of the premolded filler in conjunction with the in situ insulating material relieves strains in the connector which might otherwise be set up by a single large solid piece of in situ formed molded material.
BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be better understood fro-m the following description when read in conjunction with the accompanying drawings in which:
FIG. 1 is a front view of a preferred embodiment of an electrical connector in accordance with this invention;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a cross sectional view thereof taken through line 3--3 of FIG. 2;
FIG. 4 is a cross sectional view thereof taken through line 44 of FIG. 1;
FIG. 5 is a top view of the connector of FIG. 1;
FIG. 6 is a top view of an element thereof;
FIG. 7 is a side view of the element of FIG. 6;
FIG. 8 is a front view of an element thereof;
FIG. 9 is a side view of the element of FIG. 8;
FIG. 10 is a top plan view of another element thereof;
FIG. 11 is a top view of still another element thereof;
FIG. 12 is a cross sectional view taken through line 12-42 of FIG. 5
FIG. 13 is a front view of an alternate embodiment thereof;
FIG. 14 is a cross sectional view taken through line 14-14 of FIG. 13; and
FIG. 15 is a cross sectional view taken through line 15-15 of FIG. 14.
3 DESCRIPTION OF PREFERRED EMBODIMENTS With reference now to the drawings, a preferred embodiment of the electrical connector in its assembled form is shovm in FIGS. 1-5 and designated as 10. The electrical connector has an enclosing housing 11 opened at a connection end 12 with a plural lead electrical cable 13 joined to the housing with leads 14 electrically connected to a predetermined array of contact pins 15 mounted on a terminal board 16 within the enclosure formed by the housing. A contact housing cover block 17 faces the connection end of the housing with the inside of the housing filled by a preformed plastic collar molding 18 and an in situ formed insulating material plug 19. Hold down jack screws 20 and 21 pass through the housing and the terminal board 16 for clamping the connector to a mating connector or a mating terminal of a device such as a computer chassis (not shown).
The housing 11 of the preferred embodiment as best shown in FIGS. 3, 4, 8 and 9 is generally rectangular in configuration and preferably formed of a one-piece metallic stamping having a front wall 30, rear wall 31, side wall 32 and opposing side Wall 33 with front and rear walls and 31 generally planar and parallel to each other as are side walls 32 and 33. Top wall 34 forms a closed end of the enclosing housing. An outwardly offset skirt 35 is provided as an extension of the walls ending at the connection end or mouth 12. Any electrically conductive RF. shielding material can be used for the housing 11 although conventional iron-containing sheet metal as for example of thickness is preferred because of its ease of drawing into the required form and low cost. Moreover, such metal provides mechanical ruggedness to the connector since the housing is rigid thus preventing damage in use while additionally acting to support the components within the housing. The housing surrounds substantially the entire connector body forming a complete R.F. interference shield.
A metallic, electrically conductive ferrule 36 (FIG. 12) passes through a snugly fitting circular opening 37 in wall 34 and is soldered to wall 34 to provide for electrical continuity and mechanical strength between the ferrule and the housing. Preferably the ferrule is provided with an outer rebated shoulder 38 which acts to interlock the insulating collar 18 as will be described. An inner bore 39 of the ferrule is sized to snugly receive an end of the electrical cable 13 as best shown in FIG. 12. The electrical cable 13 can be any conventional shielded cable having a plurality of leads 14 attached to contact pins to interengage the cable with corresponding leads of another device or cable. In the preferred embodiment, cable 13 has an outer insulating sheath 40 and a conventional braided metallic sheath 41 which acts "as an RF. shield for the insulated leads or wires 14. The number of leads can vary depending on the particular application for the connector. 104 lead connectors can easily be formed. In most cases, one contact pin is provided for each lead. However, fewer pins can be used if 2 or more leads are to be attached to certain of the pins. The cable 13 is electrically and mechanically attached to the housing by solder connection 41' of the shield 41 to the inner end of the ferrule 36 as best shown in FIG. 12.
Preferably, strain relief for the electrical cable 13 is provided by an integral molded in place casing 42 which surrounds the housing 11 and is formed with an enlarged collar 43. The collar 43 and the entire casing 42 are formed of a suitable rubber or other insulating material such as Lexan to provide strain relief to the cable at the portion passing out of the housing beyond the ferrule 36.
Recessed slightly from the connection end 12 of the housing is a contact housing cover block 17 best shown in FIGS. 2, 3, 4 and 11. The cover block 17 has a depressed cutout portion for snug reception of the terminal board 16 as will be described, and a plurality of through holes 51 corresponding in position to the contact pins of the terminal board to allow electrical connection of these contact plus with corresponding mating pins in use. The cover block 17 carries male locating prongs or pins 51 and 52 at two corners thereof and female locating prongs 53 and 54 at opposing corners thereof as best seen in FIG. 2. The locating prongs as best seen in FIG. 4, are mounted in two diameter portion bores in cover block 17 and have screw threaded portions 55 passing through the block. Metallic tabs 56 are threaded with each of the locating pins and positioned adjacent a corresponding Wall of the housing. Each of the four tabs 56 is located to lie adjacent holes 57 (FIG. 8) provided in the front and rear wall of he housing 11 and a solder connection is made through the holes to lock the tabs to the housing in their proper position to in turn locate the cover block and form a closure for the housing 11 at the connection end 12. The cover block is formed of an insulating material such as a plastic which may be Bakelite, Lexan, or phenol-formaldehyde of various types as known in the art.
The terminal board 16 of the preferred embodiment has a rectangular configuration and defines parallel inner and outer surfaces 60 and 61 respectively as best seen in FIG. 7. The board is formed of an insulating material such as of plastic. Lexan, a trademarked product of the General Electric Company comprising a polycarbonate, or the like as known in the art is preferred to provide rigidity to the terminal board. In the preferred embodiment, seventy-five contact pins 15 are mounted parallel to each other in the terminal board passing therethrough. The contact pins of the preferred embodiment are arranged in six straight line alternate rows of twelve and thirteen pins each, in a predetermined array. The number and type of contact pins used can vary greatly depending upon the design and use intended for the specific connector made.
The terminal board is preferably premolded with through openings which comprise bore portions 61 and semicircular openings 62 sized to snugly receive each contact pin.
In the preferred embodiment, the contact pins 15 have female outer ends 63 with semicircular inner ends 64. Such pins can be conventional pins known in the art where the female portion is formed of a split tubular end ending at a shoulder 65 abutting a preformed shoulder in the terminal board as best shown in FIG. 3 and integral with an inwardly extending semi-tubular portion 66. The semi-tubular portion 66 is preferably provided with a hole 67 to enable mechanical tying of a selected one of leads 14 in electrical interengagement. Alternately, soldered or fused connections can be made between the leads and the contact pins or both tying and soldering can be used. In some cases, holes 67 can be eliminated and solder connections made exclusively.
Between the inner ends 64 and outer end 63 of each contact pin 15 is a hole 69 positioned with at least a portion thereof above the inner surface 60 of the terminal board. Holes 69 in each of the six rows of contact pins are aligned as best shown in FIGS. 6 and 7. These holes act along with glass rod 70, as a part of a locking means to prevent movement of the contact pins along their axes outwardly of the housing as during in situ molding of insulating materials within the housing and during use when the connector is disengaged from a mating connector.
The shoulders 65 prevent inward axial movement of the contact pins due to the stop portion formed by the terminal board. However, in conventional constructions, only tight snug fit of the contact pins prevents outward movement of the contact pins toward the connector end 12. In the embodiment 10, preferably uniform diameter insulating rods 70 are passed through a plurality of holes 69 in each of a plurality of contact pins lying along the linear rows as best illustrated in FIG. 6. The rods 70 coact with the inner surface 60 locking the contact pins against axial movement toward the connection end 12.
These insulating rods can be formed of any hard, mechanically strong insulating material. Thermosetting plastic impregnated glass rod bundles have been found to be particularly suitable for use. For example, in the preferred embodiment each rod 70 is 2.00 inches long and has an outer diameter of 0.06 inch. Each rod is made up of elongated substantially parallel glass strands impregnated with phenol-formaldehyde resin.
The space within the housing 11 is filled in part by a pre-molded insulating collar 18 which may be of insulating plastic material such as Lexan or the like. The collar 18 is provided with pre-molded bores for passage of the ferrule 36, and with bores 70 on either side thereof for passage of jack screws 20 and 21 which also pass through pre-molded bores 71 and 72 in the cover block 17. The jack screws 20 and 21 are preferably identical although one may be provided with a female end and another with a male end if desired as will be described.
Jack screw 20 (FIG. 4) comprises a knurled circular knob end 75integral with a circular shaft 76 having a circular notch 77 with a male threaded end 78. A slot 79 (FIG. 9) is provided in the housing 11 adjacent the circular notch portion 77 to enable passage of a resilient sheet metal clip 80 to fix the jack screws in position within the housing while allowing rotation thereof. Both side walls 32 and 33carry a slot 79 for mounting of the jack screws 20 and 21 respectively. A clip 80 in conjunction with each jack screw acts to provide R.F. shielding for the opening caused by the slot 79 in the housing.
The interior of the housing not filled by the pre-molded insulating collar 18 is embedded or potted, i.e., insulating material is injected into the space to form the insulating material plug 19 in situ thereby filling the space and providing mechanical support for the leads 14 as well as the terminalboard. Since the space within the housing 11 may be large as for example in the preferred embodiment where thehousing has a height of 2% inches, a width of 2 /2 inches and a depth of 1 inch, the use of the pre-molded collar 18 in conjunction with the insulating material plug formed in situ, permits a minimized amount of in situ plug formation which maximizes strain relief properties of the connector.
In assembling the connector 10, the ferrule 36 is slid over the end of cable 13* and the cable 13 is passed into the housing. The shield is soldered to the ferrule. The ferrule is then passed back into the housing and the solder connection ma'jde at 37. Pre-molded collar 18 is then positioned as shown in FIG. 3.
The terminal board is assembled with the contact pins having holes 69 in the six aligned rows. Glass impregnated rods 70 are forced through holes 69 to firmly engage and align the contact pins.
Suitable ones of leads 14 are electrically attached to predetermined; suitable ones of contact pins 15. The assembled terminal board is then positioned within the recess in the cover block 17 along with the locating pins 51, 52, '53 and 54 and attached tabs 56. The cover block and terminal board assembly is then positioned with the tabs 56 adjacent holes 57 and solder connections are made to the housing. The insulating material plug 19 is then formed in situ by known techniques leaving a circular bore for the jack screws 20 and 21 which are then positioned in FIG. 4. The entire assembly is then placed in a molding cavity with the strain relief casing 42 integrally formed thereover to complete the assembly and fabrication. Tabs 80 are snapped into position through slots 79 as the last step. The finished connector can be joined to the terminal board of a device as diagrammatically illustrated at 85 in FIG. 4 with male connector pin ends passing into female ends of pins and the jack screws rotated to screw into mating male or female members of the device as known in the art. Other assembly techniques can be used if desired.
While a specific embodiment has been shown and described above, many modifications are possible. For example, the housing need not be generally rectangular and circular, octagonal, spherical and other shapes can be used. Similarly, the number of contact pins and their array at the connection end can vary greatly depending upon the number of leads used. The contact pins need not have female ends but can have outwardly extending male prongs in accordance with conventional practice if desired. Similarly, each of the locating pins can be male or female as desired as can the jack screw ends.
While the electrical cable is shown to enter the housing with its axis substantially perpendicular to the terminal board and the connector end, side entering cables can be used.
FIGS. 'l3-15 illustrate an alternate embodiment of the invention where the cable 13 enters a side of the housing rather than the top thereof. In this embodiment, all parts are as previously described and illustrated except that certain modifications are made to provide for side entry. Identical parts have identical numbers to the embodiment 10. In the embodiment of FIGS. 13-15, the housing 11A has a side opening indicated at 100. A ferrule 101 defines a cylindrical wall 102 which is used in conjunction with ferrule 36 soldered thereto at 101. Collar 18A is modified to have a side opening permitting entrance of the leads 14 therethrough. In all other respects, the materials, combination and interaction of the parts are as previously described.
What is claimed is:
5. An electrical connector comprising a connection en a housing defining enclosing walls open at said connection end and having R.F. shielding properties on all walls thereof,
an electrical cable having an end passing into said housing,
said cable having a plurality of insulated electrical wires and a surrounding R.F. shield,
means for locking an end of said cable in said housing,
a plurality of contact pins each having an inner end connected with a selected one of said wires and an outer end for connection with another device,
a contact pin terminal board defining a first inner surface and a second outer surface and positioned between said inner and outer ends of said contact pins to locate said pins in a predetermined array,
and locking means comprising an elongated insulating rod interconnected with a plurality of said contact pins and bearing against one of said surfaces of said board for preventing unwanted movement of said pins from said predetermined array.
2. An electrical connector in accordance with claim 1 and further comprising said array being positioned at said open connection end of said housing,
a pre-molded insulating filler collar surrounding said cable end and passing into said housing and extending beyond said cable end to fill a substantial portion of said housing and an in situ molded insulating material filling said housing between said collar and said contact pin terminal board to embed said inner contact pin ends and said connected wires.
3. An electrical connector in accordance with claim 2 and further comprising said shield of said cable being electrically and mechanically interconnected with said housing.
4. An electrical connector in accordance with claim 3 wherein a metallic ferrule is positioned between said housing and said cable shield while extending into said housing and being connected with each to anchor said cable and provide R.F. shielding.
5. An electrical connector in accordance with claim 4 wherein said ferrule carries means for locking said premolded, insulating, filler collar in said housing.
6. An electrical connector in accordance with claim 3 and further comprising an integral strain relief member molded over said housing and defining a strain relief collar surrounding a portion of said cable.
7. An electrical connector in accordance with claim 6 and further comprising jack screw means passing through said housing for locking said connector in position.
8. An electrical connector in accordance with claim 6 wherein said terminal board is planar and said cable passes through said housing along a line perpendicular to said terminal board.
9. An electrical connector in accordance with claim 6 wherein a locking tab means passes through a side wall of said housing for mounting said jack screw means in position and allowing rotation of said jack screw means.
10. An electrical connector in accordance with claim 9 and further comprising a contact terminal board cover block attached to said housing at said connection end,
said cover block defining a recess,
said contact terminal board being mounted in said recess.
11. An insulating terminal board defining a first surface and a second surface,
a plurality of contact pins each defining first and second ends and an elongated axis,
each of said pins further defining an opening therethrough at a predetermined distance from its said second end,
said pins being mounted in said terminal board in parallel alignment with each of said openings positioned at said first surface,
and an elongated insulating locking rod passing through said openings and preventing unwanted movement of said pins with respect to said terminal board when force is applied toward said first ends whereby said pins are firmly held in position with respect to said terminal board.
12. An insulating terminal board in accordance with claim 11 wherein each of said pins defines a locking shoulder between said first and second terminal board surfaces for preventing movement of said terminal pins in a first direction toward said second ends,
said locking rod preventing movement of said pins with respect to said terminal board toward said first ends.
13. An insulating terminal board in accordance with claim 12 wherein at least some of said pins are aligned along a straight line and each of said openings is of equal size and is aligned along a straight line.
14. An insulating terminal board in accordance with claim 13 wherein a plurality of identical rows of contact pins are provided mounted in said terminal board,
and an insulating locking rod is mounted in each row.
15. In an electrical connector having a housing defining enclosing walls open at a connection end with said housing having R.F. shielding properties on all walls thereof, and an electrical cable having a plurality of insulated electrical leads and a surrounding R.F. shield with the cable having an end passing into the housing,
the improvement comprising,
a locking ferrule joined to an opening provided in a wall of said housing,
said cable end being snugly received in said ferrule and having means joining the shield of said cable with said housing in electrical and mechanical engagement,
a terminal board mounting a plurality of electrical contact pins positioned at said connection end,
said electrical leads being attached to selected ones of said contact pins,
insulating means filling said housing between said terminal board and said enclosing walls,
and said insulating means comprising a pre-molded insulating filler collar surrounding said cable end and passing into said housing and extending beyond said cable end to fill a substantial portion of said housing and an in situ molded insulating material filling said housing between said collar and said contact pin terminal board embedding said inner contact pin ends and said connected leads.
16. The improvement of claim 15 wherein said collar is mechanically interlocked with said locking ferrule.
17. The improvement of claim 16 and further comprising an integral molded strain relief member surrounding said cable and at least a portion of said housing.
References Cited UNITED STATES PATENTS 2,425,679 8/1947 Jackson 339-196 M X 1,152,005 8/1915 Clark 339-136 M X 3,197,730 7/1965 Hargett 339-94 M X 1,722,816 7/1929 Meunier 339 92 M X 3,375,481 3/1968 Parnell 339 94 M 3,126,244 3/1964 Raygor et al. 339-217 R X FOREIGN PATENTS 190,570 7/1957 Austria 339-217 R RICHARD E. MOORE, Primary Examiner US. Cl. X.R.
33994 M, 102 R, 143 R, 217 R, 218 M