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Publication numberUS3347979 A
Publication typeGrant
Publication dateOct 17, 1967
Filing dateJan 20, 1966
Priority dateJan 20, 1966
Publication numberUS 3347979 A, US 3347979A, US-A-3347979, US3347979 A, US3347979A
InventorsHoffman Norman E
Original AssigneeAmp Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrical connector with audible indicator means
US 3347979 A
Abstract  available in
Images(3)
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Claims  available in
Description  (OCR text may contain errors)

@d W, fi? N. E. HOFFMAN ELECTRICAL CONNECTOR WITH AUDIBLE INDICATOR MEANS Original Filed June 10, 1963 5 Sheets-Sheet l .INVENTOR. NORMAN E. HOFFMAN q M+W l 17, 1967 N. E. HOFFMAN 3,347,979

ELECTRICAL CONNECTOR WITH AUDIBLE INDICATOR MEANS Original Filed June 10, 1963 3 Sheets-Sheet 2 INVENTOR. NORMAN E. H w 4m BY M,M* W

Um. w, 1%? N. E. HOFFMAN 3,347,979

ELECTRICAL CONNECTOR WITH AUDIBLE INDICATOR MEANS Original Filed June 10, 1963 3 Sheets-Sheet 5 INVENTOR. v Newman 5- HQFFMAN- United States Patent 3,347,979 ELECTRICAL CONNECTOR WITH AUDIBLE INDICATOR MEANS Norman E. Hoffman, Harrisburg, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Continuation of application Ser. No. 286,652, June 10, 1963. This application Jan. 20, 1966, Ser. No. 521,77 3 8 Claims. (Cl. 1174-87) This application is a continuation of application Ser. No. 286,652, filed June 10, 1963, now abandoned.

This invention relates to improvements in screw-on type electrical connectors utilized to provide an insulated mechanical and electrical interconnection between the stripped ends of two or more electrical conductors.

The Wide-spread need for a low-cost insulated connector for interconnecting power supply conductors has sponsored the development of a variety of connectors having a tapered insulating cap containing a spring member adapted to force the ends of conductors to be connected together.

The uses of connectors of this type are many and varied, including use in a very substantial number of the house, building and factory power wiring circuits installed in recent times. In such use, the connector is most typically installed by semi-skilled labor frequently under adverse conditions. For example, the connector may be employed in relatively inaccessible locations, such as in terminal boxes disposed within building walls or within conduit disposed within concrete subflooring, sealed off by either plaster or cement grout. Such use makes it difficult to locate and replace faulty connections, and particularly necessary to assure against accidental grounding of the wires connected for reasons of safety, including the prevention of fire. For these reasons, it is desirable that the connector utilized be properly installed with the wires fully inserted with the insulating cap thereof and held in an interface contact which will be maintained throughout the life of the connection.

One shortcoming of the prior art connectors is that there is no adequate means to insure that a connection is properly made. Because of this it is frequently the case that the person applying the connector will fail to engage the wires to be connected fully within the connector, with the result that the conductors therein will become disengaged, causing a connection failure or at the very least, permitting the conductors to create a dadgerous exposure of hot wires. On the other hand, the person installing the connector may, by excessive twisting, so work the Wires as to break or shear the conductive strands, such that either a connection failure will occur or the sheared wire ends will drop out of the connector at some time thereafter. The above problems are aggravated in situations wherein it is not possible to make a visual inspection of the connector.

Accordingly, it is one object of this invention to provide an improved insulating connector assembly adapted to interconnect the stripped ends'of electric conductors in a manner whereby adequacy of connection is assured.

It is a further object of the invention to provide an improved connector assembly incorporating means to certify the proper use of the connector in interconnecting electric conductors without the need for visual inspection.

Patented Oct. 17, 1967 "ice It is a particular object of the invention, to provide an insulated connector cap adapted to interconnect electric conductors incorporating a feature whereby the person installing the connector may easily determine at what point conductor wires inserted within the connector are fully engaged.

It is another object of the invention to provide an improved connector assembly incorporating as a feature, means to automatically prevent excessive strains being placed upon conductors interconnected therewithin.

It is yet another object of the invention to provide an improved connector assembly having a novel tapered spring member adapted to provide a more reliable interconnection between electric conductors.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there are shown and described illustrative embodiments of the invention; it is to be understood, however, that these embodiments are not intended to be exhaustive nor limiting of the invention, but are given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use, so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

The foregoing objects are attained by the present invention through the use of an insulating cap having an internal bore adapted to accommodate a coiled spring member featuring a wire configuration adapted to cooperate with cam surfaces integral with the cap member and operable in a manner manifesting to the person installing the connector, the completion of a proper connection by a distinct change in rotational force required to twist the connector cap. In one embodiment the coiled spring member is secured within the insulating cap with one end thereof in engagement with a cam surface in one end of the cap to provide a distinct difference in required applied rotational force, and a distinct audible click when the conductors inserted therein are properly positioned. Another embodiment features an insulating cap having cam surfaces at either end and a coiled wire secured therein, having ends shaped to cooperate with the cam surfaces of the cap to provide a distinct change in required applied rotational force when the conductors inserted therein are properly seated. In both embodiments the disposition of the coiled wire member is such as to force the conductors inserted therein into a stable interface contact of relatively low resistance. In both of the embodiments of the invention the cam surfaces and ends of the coiled wire are arranged so that when the conductors are properly seated and engaged within the assembly, no amount of further twisting will operate to shear the conductors. Additionally, in both embodiments the cam surface and end of the coiled wire 'is such as to permit the connector assembly to be removed from the wires without damage to either the wires or the connector assembly. In the embodiment having cam surfaces at both ends of the coiled wire means are provided to relax the grip of the coils upon the conductors inserted therein upon rotation of the assembly in the directiotn of removal.

In the drawings:

FIGURE 1 is a perspective showing the assembly of the invention in engagement with two conductors to perform an interconnection therebetween;

FIGURE 2 is a perspective, exploded and partially sectioned of the assembly of the invention in one embodiment;

FIGURE 20 is a plan view of the camming surface of the embodiment of FIGURE 2, taken along lines Za-Za;

FIGURE 2b is a sectional view taken along lines Zb-Zb, of the camming surface of the embodiment shown in FIGURE 2;

FIGURE 20 is a sectional view taken along the lines 2c2c of FIGURE 2;

FIGURE 3 is a perspective view, partially sectioned, showing the invention of the one embodiment assembled and positioned to receive two electrical conductors;

FIGURE 3a is a sectional view taken along the lines 3a-3a of FIGURE 3;

FIGURE 4 is a perspective view, partially sectioned, showing the invention of the one embodiment with two electrical conductors fully engaged therein;

-FIGURE 4a is a sectional view taken along the lines ta-4a of FIGURE 4;

FIGURE 41) is a sectional view taken along the lines 4b4b of FIGURE 4;

FIGURE 5 shows the assembly of the invention having conductors engaged therein and fully seated and depicts the operation of the assembly caused by further rotation; which operation results in the action of the assembly to certify proper conductor engagement and to preclude excessive twisting of the conductors;

FIGURES 5a and 5b are sections taken along the lines 5a5a, 5b5b of FIGURE 5, showing, respectively, the positions of the spring end of the invention during cap rotation;

FIGURE 6 shows the assembly of the invention as shown in FIGURE 5 with the conductors and spring backed away from the engaged position following cap rotation in an opposite direction for disengagement of the conductors;

FIGURE 6a is a view similar to FIGURE 5:: showing the position of the spring end to prevent spring rotation relative to the cap during disengagement of the conductors;

FIGURE 7 is a partially sectioned exploded view of another embodiment of the invention, including cam surfaces within the insulating cap member at opposite ends of the spring member;

FIGURE 8 is a perspective view showing the opposite side of the insert shown on the left of FIGURE 7;

FIGURE 8a is a perspective view showing an alternative form of the insert of the device of FIGURE 7;

FIGURE 9 is a perspective fragmentary view illustrating the camming surface of the housing;

FIGURE 10 is a side elevation of the spring member of the embodiment of FIGURE 7; and

FIGURE 11 is a perspective view in full section showing the assembly of FIGURE 7.

Referring now to FIGURE 1, there is depicted in the hands of a mechanic, the device of the invention assembly 10, in the process of being installed to interconnect conductors 18 and 20. Conductors 18 and may be considered as standard solid or stranded wire jacketed with an insulating sheath. Conductors of this type are frequently found in 110 or 220 volt electric systems such as those used to supply power to houses, buildings and the like.

Following approximate positioning of the conductors, the device 10 is rotated in the direction shown by the arrow, with the conductors held relative thereto and forced under slight pressure into the assembly. As will be hereinafter described in detail when the conductors are properly and fully engaged within 10 the mechanic will be made to feel a distinct difference in the amount of force required to twist the assembly 10 relative to conductors 18 and 20. As an additional feature further rotation of assembly 10 results in a distinct clicking also apprising the mechanic of the proper engagement of the conductors within the assembly. Following certification, continued and excessive twisting of assembly 10 about conductors 18 and 20 will not serve to shear the conductor ends due to a ratcheting feature which permits the assembly housing to be rotated with respect to the assembly spring member holding the conductors together. The assembly 10 may be removed by rotation in the opposite direction to that indicated with the conductors again held fast as in the manner of insertion.

Turning now to a detailed description of the assembly of the invention in one embodiment, reference is made to FIGURE 2, and the partially sectioned perspective showing the assembly to be comprised of two components; a one-piece housing 16 of insulating material and a metal coiled tapered spring 40. Housing 16 is preferably an integral structure formed of a molded thermoplastic resin, aS for example, nylon having insulating qualities, resiliency and a substantial toughness and resistance to shear open at one end, as at 17, and closed at the other end by a cap 22. The interior of 16 defines a bore 36 of substantially constant diameter adapted to retain spring 40. The wall thickness of 16 is sufliciently thick, considering the characteristics of the material of which it is comprised, to withstand the forces imparted to the structure during assembly, as will be more fully explained hereinafter. Extending radially from 16 are wings 12 and 14 adapted to provide surfaces whereby the assembly may be more easily gripped for rotation during installation.

As shown in FIGURES 2, 2a and 2b, cap 22 includes an interior surface having a central raised cylindrical portion 34 which serves as a conductor stop, a recessed volume surrounding 34, shown as 28, and an outer raised portion or plane 2 extending around the circumference of 34 and slotted as at 30. The raised portion 24 forms an inclined camming surface 26 leading from slot 30 and a face 31 thereof around at an increasing height relative to the interior transverse surface of 22 to a face 32 of substantially greater height than face 31, the function and further features of which will be more fully described hereinafter.

Axially disposed from cap 22 and extending within the bore 36 of housing 16 is a projecting rim 38 which acts as a spring retainer. As indicated in FIGURE 2, rim 38 is bevelled on the entry side thereof for receiving the spring member 40 and is substantially flat on the other side thereof to form a perpendicular surface relative to the surface of bore 36 for retaining spring 40. Rim 38 is shown as integrally formed with housing 16, but may be a separate piece secured thereto in a manner to be described with respect to a further embodiment of the invention.

Coiled spring 40 includes at one end a radial extension 42 joining a section of turns 41 which are closely spaced relative to each other and of a relatively low pitch. Joining section 41 is a further section 45 having wire turns of a substantially higher pitch with spacings between each turn of the coil as indicated by numeral 46. Section 45 terminates at an end 44, having substantially the same configuration as the preceding turn of the coil. Spring 49 is preferably a stiff compression spring and of a length slightly longer in its relaxed state than the longitudinal dimension of bore 36 as measured from the inner surface of flange 38 to the bottom surface of cap 22.

The largest external diameter of spring 40' or the diameter occurring in section 45 thereof is slightly less than the diameter of bore 36. The smallest external diameter of spring 40, of course, depends on the diameter of the wire utilized for the spring and the spring taper but is made such as to define a diameter considerably less than the diameter of the housing bore 36 to accommodate expansion for a given range of conductor sizes or number of conductors employed. The interior diameter of the last turns of section 41 is less than twice the diameter of the smallest conductor to be utilized with the assembly for a given range of wire sizes.

Assembly of spring 40 within housing 16 is preferably accomplished before use and shipment with the spring being inserted in the direction shown to a point wherein the last turn is seated against rim 38, with opposite end 42 nesting in slot 30 of cap 22. The diameter of section 45 of spring 40 assures that spring 40 will not be accidentally dislocated from within the shell or housing 16.

FIGURE 3 shows assembly with spring 40 engaged as above described and conductors 18 and 20 suitably stripped and positioned for insertion within the assembly. As will be apparent from FIGURE 3, end 42 is nested within slot 30 and conductor stop 34 is nested within the turns adjacent end 42; i.e., within one end of section 41 of spring 40. The cooperation betwen spring 40 and conductor stop 34 assures that spring 40 is properly seated and aligned within the assembly both prior and during use of the assembly in interconnecting conductors 18 and 20. As FIGURE 3a shows, the end 42 of spring 40 may be considered as resting within slot 34] without particularly bearing against either of the faces 31 and 32.

To operate the assembly, the bared ends of conductors 18 and 2d are inserted within the entry portion 17 of housing 16 down into the interior of section 45 of spring 4t? to engage the interior thereof at some point wherein the diameter of the interior of the spring is smaller than the combined diameters of the conductors 18 and 20. The taper of spring 40 operates to guide the two conductors together. With the conductors and assembly held as indicated in FIGURE 1, a slight forcing together of the conductors and the assembly 10 with a counterclockwise rotation relative to the entry end thereof opcrates to draw the conductors down within spring 40 the interior surfaces of the spring turns operating on the conductors much as a screw thread. Continued rotation in addition to further drawing the conductors axially along the interior of the assembly into spring section 41, tends to force the conductors together into intimate contact to form an interface therebetween suflicient to define a relatively low resistance stable electrical path between conductors. This is shown in FIGURES 4 and 4b. As assembly 10 is rotated in the counter-clockwise direction with conductors 18 and 20 held fast, spring 40 also ro- :tates by reason of the bearing relationship of end 42 thereof against face 31 within slot 30.

Since the interior diameter of section 41 of spring 40 is substantially less than twice the diameter of the conductors 18 and 20, the spring 40 must gradually expand as the conductors proceed toward stop 34 in the axial direction within assembly 10. The forced expansion of 4d serves to gradually increase the forces driving the conductors together. Additionally, the threading of the conductors through the various turns of 41 forms indentations wiping the conductors and breaking the surface corrosion thereon to form conductive path through spring 40 between the conductors. This feature, although not relied upon for defining the connection achieved may be useful in instances wherein more than two conductors are terminated by the assembly.

Continued rotation of 10 results in conductors 18 and 20 being drawn axially within spring 40 to a point wherein the ends of the conductors bear against the face of stop 34 as shown in FIGURE 4. At this position of axial movement the electrical and mechanical connection between conductors 18 and 20 is completed and further rotation of assembly 10 serves no useful purpose. In prior art devices it is at this point that further rotation imparts shearing strains to the conductors causing a diminution in the quality of connection and in many instances a complete failure of connection by shearing the conductors and/ or housing. It is at this point that the ratcheting and certifying features of the assembly of the invention come into play.

Viewing now FIGURE 5 the operation of the ratcheting and certifying feature will now be explained. Considering the last several turns of the assembly 10 the forward turns in section 41 of spring 40, by the gripping relationship with respect to the conductors 18 and 20, force the wire ends to be driven against the face of stop 34. This results in spring 40 being forced in the opposite direction in compression. The provision of spacings 46 between turns in section 45 permits axial movement of the spring. As this occurs spring 40 backs away from cap 22 and lifts the last turn and end 42 of slot 30 and off faces 31 as shown in FIGURE 5a. Since the bearing relationship between end 42 and face 31 is no longer present, coil 40 then ratchets or rotates freely with conductors 1S and 20 within the bore 36 of 16. As this occurs the amount of force necessary to rotate assembly 10 relative to conductor wires 18 and 20 is distinctly and drastically reduced, thus signifying to the mechanic that the connection has been properly completed and that further rotation of the assembly In is unnecessary. Furthermore, since housing 16 may now rotate freely, the shearing strain imparted to conductors 18 and 20 by continued rotation is substantially eliminated.

This last motion of spring 40 as the end turns in section 41 are driven axially and the turns in section 45 are compressed further operates to achieve an elastic reserve extending radially inwardly forcing the wires 18 and 29 together and against the stop 34. This additional movement of coil 40 also serves to cause the inner coil faces to penetrate deeper into the conductive material of conductors 18 and 20, as the wires are forced into the smaller diameter turns of the spring.

As a further and additional certifying feature of the embodiment above described, continued rotation of assembly 10 after end 42 has been raised to the position shown in FIGURE 5a results in the end being rotated and lifted about cam surface 24 approximately 360 as shown in FIGURE 5b. As end 42 clears face 32 it is forced by additional spring compression to snap down off the cam surface over slot 30. This results in a clicking sound further indicating to the operator that the proper connection has been accomplished.

In the event that it is desired to remove the assembly 10 from the conductors the assembly may be rotated in the clockwise direction until end 42 of spring 40, as indicated in FIGURES 6 and 6a, bears against face 32. This results in the spring being held fast relative to housing 16 and continued rotation results in the backward threading of the spring 40 relative to conductors 18 and 20 to remove the assembly. As this process takes place in a reverse sense to that described with respect to FIGURES 3-5, spring 40 is caused to expand to its original length and configuration such that reinsertion of the conductors and subsequent rotation of 16 will cause the end 42 to reseat against face 31 in slot 30, thus preparing the assembly for a repeated engagement of conductor wires.

While the housing 16 is shown as an integral one-piece plastic structure, it is fully contemplated that by employing fabricating techniques known to those skilled in the art, the assembly housing could be made in more than one piece. For example, the housing 16 could include an internal threading proximate the end cap 22. which itself would be externally threaded to mate with 16 to form the assembly.

FIGURES 7-11 show partially sectioned perspective views of a further embodiment of the assembly of the invention, wherein cam surfaces are provided at each end of a tapered coil spring member.

As shown in FIGURE 7, the assembly 50 includes a housing 52 securing a tapered coil spring member therein and has a general operation and function identical to that of assembly 10 heretofore described. Integrally formed with housing 52 are wings 54 and 56 suitable to facilitate rotation of the assembly in the same manner as heretofore described. Also, similar to the construction of the device heretofore described is a central bore 58 extending along the length of housing 52. At one end of the housing is an opening 60 adapted to accommodate the entry of a plurality of conductive wires to be mechanically and electrically connected by the assembly. At the other end is a cap portion 62 having a recessed face better revealed in FIGURE 9. The recessed face is formed by 90 segments 64 and 66 having, respectively, a bottom surface of constant depth and a surface of gradually increasing axial thickness to form a cam surface with a 180 segment forming an upper face. The segments are adjoined and include at one end a face 68 and at the other end a transition portion 70. The function and purpose of the features of cap 62 will be described hereinafter.

Secured within bore 58 at a point spaced from the opening 60 forming the entry portion of housing 52 is an insert 72 of a generally annular shape having a central bore 74 sized to accommodate conductive wires inserted into the housing. The insert 72 further includes an outwardly disposed radial flange portion 76 adapted to fit within a complementary bore 78 against face 59 of housing 52 and be bonded thereto. Formed on an interior portion of 72 is an axially projecting cam surface 80 of the configuration best shown in FIGURE 8. Cam surface 80 includes a segment of approximately 180, which is of increasing axial thickness tapering from a point even with the surface of flange 76 up to a point of maximum thickness as at 84 to define a face 86 perpendicular to the surface of 76. The remaining 180 segment of the spring bearing surface is defined by the surface of 76. The face 86 acts to provide an audible click and serves to block spring rotation during the removal procedure through an operation analogous to face 34 of assembly 10. FIGURE 8a depicts an alternative form of insert 62 which is dimensionally identical with insert 72 except in the provisions of two cam surfaces 80, defining two spring stop faces 86. Through this embodiment the number of audible clicks per revolution is doubled.

Assembly of 50 calls for insertion of spring member 100 into bore 58 with one end being seated against the surfaces of end cap 62. Thereafter, insert 72 is positioned as shown in FIGURE 11 and bonded to bore 78 and face 59. A preferred method of bonding insert 72 is by spinning the insert and at the same time holding 52 fixed to produce frictional heat sufficient to effectively weld the insert to 52. This approach is particularly useful when the parts are of nylon, or in fact, most any thermoplastic material. It is, of course, understood that if the parts are of materials not adaptable to the spinning technique, such parts may be glued or otherwise chemically bonded in any well-known manner, or mechanically connected as by threading. With insert 72 so installed, spring member 100 is locked within the assembly and secured against displacement therefrom.

As shown in FIGURES 7, 10 and 11, spring member 100 is quite similar to the spring described with the embodiment above treated. It includes a tapered length section 102 with closely nested turns of a given pitch joined by a section 104 with turns of constant diameter of a greater pitch and spacing. The first turn of the spring section 104 is disposed in a plane at less than 90 relative to the longitudinal axis of the spring to form an end 108 on the section diameter. The last turns of section 102 include a gradually enlarged radius turning into a plane perpendicular to the longitudinal axis of the spring to form an end 106 having a 90 segment extending out to the diameter of section 104.

In operation, conductors such as 110 and 112 are insertecl within assembly 50. The assembly is then rotated in a counter-clockwise direction with respect to the entry portion of the assembly in the same manner as heretofore described. The wires are drawn into the assembly and gradually forced together by the threading action of the interior surface of the spring turns in section 102. Spring is held against relative rotation with respect to housing 52, by reason of end 106 bearing against face 68 of end cap 62 as shown in FIGURE 11. The ends of the conductors and 112 after a certain number of turns of assembly 52 come to bear against the center interior face of end cap 62. Further rotation of the assembly causes the more reduced diameter turns of section 102 to continue to thread back along the conductors to further drive 110 and 112 together. As the section 102 threads .back along the conductors from the ends thereof and sec tion 104 compresses, the end 106 is lifted out of the recessed portion of end cap 62 away from face 68 to slide around the face at a point above the top of face 68' in the same manner as end 42 in assembly 10. As end 106 clears face 68, an immediate and distinct reduction in required applied force to rotate the assembly is felt and an audible click results from end 108 snapping off face 86 thus certifying to the person making the installation that the assembly is properly engaged upon the conductors and that further rotation is unnecessary. During counterclockwise rotation of assembly 50, end 108 is held against relative rotation by reason of spring 100 being held through end 106 in engagement with face 68. As with assembly 10, shearing strains imparted to the conductors are substantially eliminated by the free rotation of the assembly housing relative to the spring and the conductors held therein.

The embodiment represented by assembly 50 includes a feature which facilitates removal of the assembly from the wires with the same amount of force being required to remove the assembly as was required to install the assembly. This feature is highly advantageous in applications wherein the assembly is engaged and removed. Upon rotation in the clockwise direction for removal of the assembly, spring end 106 rotates in a direction relative to end cap 62 wherein the end trails the wire turn and slides along the cam surface 66 and around the periphery of the inner surface of 62 so as not to be locked by engagement with face 68. End 108 does, however, lock spring 100 against relative movement With respect to housing 52 by engaging face 86 of insert 72. Continued rotation of the housing of the clockwise direction starts the conductors LlOCkCd in coil section 102, which then thread back through the spring. As this occurs, the spring 100 is relaxed with the end 106 and the turns in 102 moving forward axially to relieve the spring from compression and relax the grip upon the conductor Wires therein. It has been found that the operation of coil 100 in this manner permits the assembly 50 to be removed with the same or less force applied as the force required for installation.

For the purpose of aiding practice of the invention but without any intention to restrict the scope of the invention, the following details are given relative to an actual unit constructed in accordance with the invention and found to be successfully operable with solid conductors varying from one No. 10 plus one No. 12 up to three No. 8 or two No. 6 AWG sizes.

Assembly 50 (dimension in inches) Housingnylon Insertnylon Bore 58, diameter-0.468

Maximum thickness of end cap cam surface-0.06O

Maximum thickness of insert cam surface-0.060

Spring 100-type MB hard drawn steel wire, galvanized pre-coated Spring length, relaxed-1237 Spring length, compressed1.015

Maximum spring diameter-0.460

Spring taper-9 Section 102-10 turns, 0.060 pitch Section 104-2 turns, 0.200 pitch Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

1 claim:

1. An improved electrical connector for interconnecting the stripped ends of a plurality of conductors including an insulating cap having a central bore, a tapered coil spring member secured in said bore having spaces between spring turns to permit axial compression, means including a first axially extending surface positioned within said bore adapted to lock said spring member against relative rotation thereto during a given number of turns of cap and spring member in one direction as the plurality of conductors are threaded within said spring and adapted to release said spring member for rotation relative to said cap following said given number of turns of the cap in said one direction and further means in said bore including an inclined surface operable to lift an end of said spring member following the release thereof to further compress said spring member, said inclined surface terminating in a further axially extending surface positioned to engage said end of said spring member to produce a series of audible clicks as said cap is rotated following release of said spring member to thereby provide a tactile and audible certification of proper interconnection of said conductors in said cap.

2. An improved electrical connector for interconnecting the stripped ends of a plurality of conductors including in combination an insulating cap having a central longitudinal bore of a given axial length extending be tween an inwardly directed shoulder at an open end of said bore and a closed end defined by a transverse end surface, a tapered coil spring member having spaces between spring turns to permit axial compression and having an axial length when relaxed greater than said given axial length of said bore to be held in compression by said shoulder and said transverse end surface of said cap which secure and position the spring member in said bore to receive said plurality of conductors such that the spring member may be threaded thereover by rotation of said cap in one direction to force said conductors into electrical and mechanical contact within the turns of said spring member and force the conductor ends into engagement with said end surface, locking means integral with said cap holding said spring member against relative rotation to said cap during said threading, the locking means including an axially projecting surface of a length such that upon the spring member being driven into compression by the ends of the conductors being forced against the end surface of said cap, the spring will be released for rotation relative to said cap, the said locking means further including a radially disposed inclined surface intersecting said axially projecting surface and operable to lift an end of said spring member as the cap is rotated, whereby the spring end snaps downwardly to produce an audible click as the cap is rotated, and where the said locking means further includes a further axially projecting surface of a length greater than the first mentioned surface adapted to lock said spring against relative rotation to said cap as the cap is rotated in the other direction, the said further axially projecting surface being disposed in the same end of said cap as the first mentioned surface.

3. An improved electrical connector for interconnecting the stripped ends of a plurality of conductors including in combination an insulating cap having a central bore, a tapered coil spring member secured in said bore having spaces between spring turns to permit axial compression, means within said cap adapted to lock said spring member against relative rotation thereto during a given number of turns of cap and spring member in one direction as the plurality of conductors are threaded within said spring and adapted to release said spring member for rotation relative to said cap following said given number of turns of said cap in said one direction and further means in said cap positioned to engage an end of said spring member to produce a series of audible clicks as said cap is rotated following release of said spring member whereby to provide a tactile and audible certification of proper interconnection of said conductors in said cap, said cap including further means adjacent said first mentioned means for locking said spring member against relative rotation to said cap as said cap is rotated in the other direction.

4. An improved electrical connector for interconnecting the stripped ends of a plurality of conductors including an insulating cap having a central longitudinal bore of a given axial length extending between an inwardly directed shoulder at an open end of said bore and a closed end defined by a transverse end surface, a tapered coil spring member having spaces between spring turns to permit axial compression and having an axial length when relaxed greater than said given axial length of said bore to be held in compression by said shoulder and said transverse end surface of said cap which secures and positions the spring member in said bore to receive said plurality of conductors such that the spring member may be threaded thereover by rotation of said cap in one direction to force said conductors into electrical and mechanical contact within the turns of said spring member and force the conductor ends into engagement with said end surface, locking means integral with said cap including an axially projecting surface holding said spring member against relative rotation to said cap during said threading, said axially projecting surface being of a length such that upon the spring member being driven into compression by the ends of the conductors being forced against the end surface of said cap, the spring end will be drawn off of said projecting surface so that said spring member is free for rotation relative to said cap, the said cap further including a radially disposed inclined surface extending within said bore and terminating in a further axially projecting surface of greater axial length than said first mentioned axially projecting surface, said inclined surface being positioned and operable to lift said end of said spring member as the cap is rotated so that said end snaps downwardly to produce a series of audible clicks as the cap is rotated.

5. An improved electrical connector for interconnecting the stripped ends of a plurality of conductors including in combination an insulating cap having a central longitudinal bore of a given axial length extending between an inwardly directed shoulder at an open end of said bore and a closed end defined by a transverse end surface, a tapered coil spring member having spaces between spring turns to permit axial compression and having an axial length when relaxed greater than said given axial length of said bore to be held in compression by said shoulder and said transverse end surface of said cap which secures and positions the spring member in said bore to receive said plurality of conductors such that the spring member may be threaded thereover by rotation of said cap in one direction to force said conductors into electrical and mechanical contact within the turns of said spring member and force the conductor ends into engagement with said end surface, locking means integral with said cap holding said spring member against relative rotation to said cap during said threading, the locking means including an axially projecting surface of a length such that upon the spring member being driven into compression by the ends of the conductors being forced against the end surface of said cap, the spring will be released for rotation relative to said cap, the said locking means including a radially disposed inclined surface intersecting said axially projecting surface and operable to lift an end of said spring member as the cap is rotated, whereby the spring end snaps downwardly to produce an audible click as the cap is rotated, the locking means further including a further axially projecting surface of a length greater than the first mentioned surface adapted to lock said spring against relative rotation to said cap as the cap is rotated in the other direction.

6. An electrical connector comprising a cap of insulating material having an internal bore of a given axial length adapted to receive and insulate the stripped ends of a plurality of electrical conductors, a spring member having a relaxed axial length greater than said given axial length, means within said bore adapted to captivate said spring member, said spring member being comprised of a length of coils with progressive turns being of a reduced diameter to define an interior taper having a section substantially less in cross-sectional area than the cross-sectional area of a circle defined by the peripheral points of conductors inserted therein, a projecting surface disposed in one end of said cap adapted to lock said spring against movement relative to said cap during engagement of said conductors to permit rotation in one direction of said cap to thread said conductors Within said spring to a point wherein the ends of said conductors engage a transverse inner face of said cap, the said spring including a section of spaced coils adapted to permit axial compression of said spring by the conductors inserted therein bearing against the inner face of said cap, the said projecting surface having a length such as to release said spring for relative rotation within said cap following axial movement of the end of said spring as the spring is compressed by the ends of said conductors bearing against the inner surface of said cap, the said projecting surface of said cap joining a cam surface inclined to round said cap inner surface and there is included a second projecting surface of a greater length adapted to hold said spring against relative rotation in the other direction to permit said conductors to be threaded out of said spring.

7. An improved electrical connector for interconnecting the stripped ends of a plurality of conductors including an insulating cap having a central longitudinal bore of a given axial length extending between an inwardly directed shoulder at an open end of said bore and a closed end defined by a transverse end surface, a tapered coil spring member having spaces between spring turns to permit axial compression and having an axial length when relaxed greater than said given axial length of said bore to be held in compression by said shoulder and said transverse end surface of said cap which secures and positions the spring member in said bore to receive said plurality of conductors such that the spring member may be threaded thereover by rotation of said cap in one direction to force said conductors into electrical and mechanical contact within the turns of said spring member and force the conductor ends into engagement with said end surface, locking means integral with said cap including an axially projecting surface holding said spring member against relative rotation to said cap during said threading, the said projecting surface being of a length such that upon the spring member being driven into compression by the ends of the conductors being forced against the end surface of said cap, the spring will be released for rotation relative to said cap, the said cap further including a radially disposed inclined surface terminating in a further axially projecting surface and operable to lift said end of said spring member as the cap is rotated so that the said end snaps downwardly off said further axially projecting sruface to produce an audible click as the cap is rotated, the said further axially projecting surface being of a length greater than the first mentioned axially projecting surface adapted to lock said spring against relative rotation to said cap as the cap is rotated in the other direction, and the said axially projecting surfaces are each disposed at different end of said spring member within said cap.

8. An improved electrical connector for interconnecting the stripped ends of a plurality of conductors including in combination an insulating cap having a central longitudinal bore of a given axial length extending between an inwardly directed shoulder at an open end of said bore and a closed end defined by a transverse end surface, a tapered coil spring member having spaces between spring turns to permit axial compression and having an axial length when relaxed greater than said given axial length of said bore to be held in compression by said shoulder and said transverse end surface of said cap which secures and positions the spring member in said bore to receive said plurality of conductors such that the spring member may be threaded thereover by rotation of said cap in one direction to force said conductors into electrical and mechanical contact within the turns of said spring member and force the conductor ends into engagement with said end surface, locking means integral with said cap including an axially projecting surface holding said spring member against rotation relative to said cap during said threading and being of a length such that upon the spring member being driven into compression by the ends of the conductors being forced against the end surface of said cap, the spring member will be released for rotation relative to said cap, the said cap further including a radially disposed inclined surface terminating in a further axially projecting surface and operable to lift an end of said spring member as the cap is rotated so that the said spring end snaps downwardly off of said further axially projecting surface to produce an audible click as the cap is rotated, the said further axially projecting surface being of a length greater than the first mentioned surface so as to lock said spring member against relative rotation to said cap as the cap is rotated in the other direction, and the said axially projecting surfaces being each disposed at different ends of said spring member within said cap.

References Cited UNITED STATES PATENTS 3,097,257 7/1963 Cheney 17487 3,156,761 11/1964 Schinske 174 s7 FOREIGN PATENTS 657,405 9/1951 Great Britain.

DARRELL L. CLAY, Primary Examiner.

LEWIS H. MYERS, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3097257 *Nov 2, 1961Jul 9, 1963Ideal IndElectrical connector
US3156761 *Nov 26, 1962Nov 10, 1964Ideal IndConnector assembly
GB637405A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3519707 *May 9, 1968Jul 7, 1970Ideal IndMethod of making electrical connectors
US4451695 *Apr 16, 1982May 29, 1984Heyman Manufacturing Co.Connector assembly
US4707567 *Jun 13, 1986Nov 17, 1987Ideal Industries, Inc.Screw-on electrical connector and method of making it
US4803779 *Aug 21, 1987Feb 14, 1989Ideal Industries, Inc.Method for making a screw-on electrical connector
US5030128 *Mar 6, 1989Jul 9, 1991Dynabook Technologies CorporationDocking module
US5559307 *Jun 30, 1994Sep 24, 1996Thomas & Betts CorporationTwist-on connector having improved finger grip wings
US5838539 *Nov 8, 1995Nov 17, 1998Electronics Accessory Specialists InternationalDocking module for portable computers
US5894110 *Sep 30, 1996Apr 13, 1999Minnesota Mining And Manufacturing CompanyTwist-on wire connector
US7365270 *Oct 6, 2005Apr 29, 2008Thomas & Betts International, Inc.Twist-on connector
WO1990011628A2 *Mar 2, 1990Oct 4, 1990Dynabook Technologies CorpDocking module
Classifications
U.S. Classification174/87, 403/27, D13/150, 116/67.00R, 403/327, 403/396
International ClassificationH01R4/00, H01R4/22
Cooperative ClassificationH01R4/22
European ClassificationH01R4/22