US3549786A

US3549786A - Insulation piercing connector

Info

Publication number: US3549786A
Application number: US822804A
Authority: US
Inventors: Lai Che Kuo
Original assignee: Thomas and Betts Corp
Current assignee: ABB Installation Products Inc
Priority date: 1969-04-04
Filing date: 1969-04-04
Publication date: 1970-12-22
Anticipated expiration: 1987-12-22
Also published as: NL167057C; SE377406B; JPS4840944B1; DE2016360B2; GB1250148A; DE2016360A1; FR2042171A5; BE748130A; NL167057B; NL7002620A

Description

United States Patent [72] Inventor Lai Che Kuo Elizabeth, NJ.

[21 Appl. No. 822,804

[22] Filed Apr. 4, 1969 [45] Patented Dec. 22, 1970 [73] Assignee Thomas & Betts Corporation Elizabeth, NJ. a corporation of New Jersey [54] INSULATION PIERCING CONNECTOR [56] References Cited UN lTED STATES PATENTS 1,343,251 6/1920 Dillon 174/90UX 2,013,217 9/1935 Olmstead 29/432UX Primary Examiner-Darrell L. Clay Attorney-David Teschner ABSTRACT: The invention is directed to the field of insulation piercing connectors wherein the conductor contact member is formed with a plurality of hardened teeth struck from the surface of such conductor contact member. The form of the teeth is such as to provide a point and from two to five cutting surfaces to cut through the insulation of the conductor in order to make a good electrical contact therewith and to make a good mechanical contact with both the insulation and the central conductor itself. The conductor contact member will have provided with it a number of coupling means for coupling the conductor to the conductor contact member or the conductor contact member itself may be fabricated in such a manner as to be mechanically deformed about a conductor to make the desired connection.

PATENTEUUEC22I97B 3.549786 sum 1 or 2 INVENTOR.

LA/ CHE Kuo ATTORNEY PATENTED DEBZZ I570 SHEET 2 OF 2 INVENTOR. LAI CHE Kuo ATTORNEY 1 INSULATION PIERCING CONNECTOR BACKGROUND OF THE INVENTION 1. Field of the Invention Y The invention is directed to the field of making sound mechanical and good electrical contact with an insulated conductor without requiring that the insulation be removed therefrom. It is necessary that sufficient piercing of the insulation be achieved in order that a goodelectrical contact be made with the electrical conductor within plus sufficientcontact be made with both theconductor and the insulation in order to ensure a good mechanical joint. Such a connector is generally required wherein sufficient time is available to strip the insulation from the conductor or in those situations in which the removal of the insulation is difficult or such removal may injure the conductor. The connector may be also employed withsolid uninsulated conductors when it is necessary to break the oxide barrier on the outside surface of the con-- ductor in order to ensure a good electrical contact with the material of the conductoritself.

2. Description of the Prior Art Prior art insulation piercing connectors are exemplified by U.S. Pat. No. 3,265,807, issued Aug. 9, 1966, to D. T. Smith, entitled Connector for Insulated Conductors. In this patent is shown a sleeve 12 having struck through it perforations 20'and protuberances 22 having zigzag cutting edges thereon. Sleeve 12 is then placed in a metallic sleeve which in turn is placed in an insulated outer sleeve 10. The entire assembly is subjected to externally applied crimping forces in order that the cutting edges on the protuberances 22 cut through the insulation of the conductors and make contact with the conductor therein. It has been found in practice that the protuberances 22 are generally of insufficient strength to ensure a good continuous contact with the conductor through the insulation. Generally, many of the protuberances 22 are bent out of position by the application of the crimping forces and fail to make contact. Further, if the insulation is of the type generally applied to magnetic wire, crimping force applied is generally insufficient to force the protuberances 22 to cut through the coated insulation of the magnetic wire and enter into the wire to make a good electrical contact therewith. Further, the failure to penetrate the insulation and to bite into the conductor fails to make a mechanical junction therewith which results in a connector which can be readily severed, or'readily separated from the conductor and which when connected will provide a poor electrical contact therewith.

SUMMARY OF THE INVENTION The present invention seeks to overcome the difficulties noted above with respect to prior art connectors for insulated conductors by providing an insulation piercing connector of increased strength and which can provide a reliable electrical contact with the conductor through its insulation and which provides a good mechanical coupling between the connector and the insulated conductor. This is achieved by means of a novel conductor contact member which has struck from its surface a plurality of teeth that are hardened by the very process of striking them from the surface of the conductor contact member. Further, the shape of the teeth is such as to provide a point at the top thereof and from two to five cutting edges to ensure piercing of the insulation and the entry of the teeth within the material of the conductor itself. In addition, the shape of the teeth are made such as to reinforce them to prevent them from being displaced from their desired position by any crimping action which connects the connector to the conductor. Additionally, recesses are provided adjacent each of the teeth to provide space for the flowing of the insulation material, or the material of the conductor, which occurs during the crimping operation and which in prior art devices might cause the separation of the connector from the conductor during: the crimping operation. Further, the recesses permit the material of the conductor to expand without destruction of the joint.

In the first embodiment of the invention, the conductor contact member is provided in a relatively flat strip arrangement and requires the use of an additional coupling means for coupling the conductor contact member to the conductor. In further arrangements, the conductor contact member is performed in order to receive within it the conductor such that upon mechanical deformance of the conductor contact member the connector is mechanically and electrically coupled to the insulated conductor. It is an object of this invention to provide an improved insulation piercing connector.

It is still another object of this invention to provide an improved insulation piercing connector having aplurality of hard teeth struck from the surface of a conductor contact member to assure good mechanical and electrical connection with an insulated conductor. i

It is still another object of this invention to provide an improved insulation piercing connector having a plurality of teeth, each having a plurality of cutting edges to ensure a good mechanical and electrical contact therewith.

It is yet another object of this invention to provide an improved insulation piercing connector having a conductor contact member and employing separate coupling means for coupling such conductor contact member to an insulated conductor.

It is still another object of this invention to provide an improved insulation piercing connector having a conductor con tact member preformed such that it may be applied to an insulated conductor by means of externally applied crimping forces.

Other objects and features of the invention will be pointed outin the following description andclaims and illustrated in the accompanying drawings, which disclose, by way of example, the principles of the invention and the best modes which have been contemplated for carrying them out.

BRIEF DESCRIPTION OF THE DRAWING In the drawings in which similar elements are given similar reference characters:

FIG. 1 is a side perspective view of a first embodiment of a connector constructed in accordance with the concepts of the invention.

FIG. 2 is a side elevation of the connector of FIG. 1 applied to an insulated conductor by means of a coupling device.

FIG. 3 is a side elevation, partially in section, of a portion of the connector FIG. 1.

FIG. 4 is a top plan view of a portion of the connector of FIG. 1.

FIG. 5 is a top plan view of a modification of the connector shown in FIG. 1.

FIG. 6 is a top plan view of a further modification to the connector shown in FIG. 1.

FIG. 7 is a rear perspective view of a modification of the teeth of the connector of FIG. 1.

FIG. 8 is a rear perspective view of a further embodiment of a connector constructed in accordance with the concepts of the invention.

FIG. 9 is a front elevational view of the connector of FIG. 8 partially in section and shown applied to insulated conductors.

FIG. 10 is a side perspective view of a further embodiment of a connector constructed in accordance with the concepts of the invention.

FIG. 11 is a side elevational view of the connector of FIG. I

10 to a conductor.

FIG. 12 is a front elevational view of a further embodiment of a connector constructed in accordance with the concepts of the invention.

FIG. 13 is a side elevation of a further embodiment of a connector constructed in accordance with the concepts of the invention. 7

FIG. I4 is a side perspective view of a further embodiment of a connector constructed in accordance with the concepts of the invention.

FIG. 15 is a side perspective view of yet another embodiment of a connector constructed in accordance with the concepts of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIGS. 1, 2, 3 and 4 there is shown a first embodiment of a connector 20 constructed in accordance with the concepts of the invention. Connector 20 has a conductor contact member'22 coupled to a tongue 24 having an aperture 26 therein for receipt of a terminal screw therethrough. Although tongue 24 is shown as a ring terminal it may just as well be a spade lug or any other convenient shape that is desired. Skived from the surface the conductor contact member 22 are a plurality of teeth 28 forming recesses 30 adjacent each of the teeth 28. As is better seen in FIG. 3 the tooth 28a terminates in a point 32 and sits adjacent a recess 30 formed when the tooth 28a was struck from or skived from the surface of the material from which the connector 20 was formed. As is shown in FIG. 3, the recess 30 is'of minimal depth at the far end, that is to the right of FIG. 3 and is of maximum depth at the left or adjacent the face of the tooth 28. The tooth 28a as shown in FIG. 3 is that which would be created in the forming of the teeth 28, such as tooth 28a adjacent the bottom edge of the terminal 20 of FIG. 1. As a result of the striking of additional teeth such as tooth 28b there will be formed on the front surface of the tooth 28a two planar portions 34 which, as will be explained below, provide additional cutting edges.

Turning to FIG. 4, the position of all of the cutting edges of a tooth 28a can be better appreciated. As is shown the tooth 28a is followed by a recess 32 which recess will be employed to permit flowing of the insulation material and portions of the conductor itself as the tooth 28a engages the insulation and material of the conductor. It hasbeen found in the past that without provision for relief of the buildup of the insulation and metal of the conductor formed as a result of the biting of such teeth into the conductor, the material will attempt to return to positions formerly occupied and will achieve fully, or to some degree, the forcing of the tooth out of its desired position. Thus, with relief areas such as the recesses 32, there is ample space for the flow of such insulation material or the material of the conductor such that it will not interfere with the operation of the ,connector during crimping or thereafter. As a result of the skiving to form the tooth 28a the rear surface 36 of the tooth 28a is planar and thus there is created two cutting edges 38 adjacent the ends of the planar surface 36. The front face 40 of the tooth 28a is formed in a generally conical manner and has therein two planar portions 34 formed as a result of the skiving of the next adjacent tooth 28b of FIG. 1. The intersections of the planes 34 with the conical 40 of the tooth 28a result in additional cutting edges 42. It should be noted that a conductor is placed upon the conductor contact member 22 in a direction generally shown by arrow X of FIG. 1 enabling each of the cutting edges 38 and 42 to either intrude between the strands of a stranded conductor or to bite into material of the solid conductor once the teeth have passed through the material of the insulation. The connector 20 of FIG. 1 is assembled to a conductor 44, as is shown in FIG. 2, by means of a sleeve 46 which is passed over the conductor 44 and the conductor contact member 28, not visible in FIG. 2 and is then crimped, or otherwise mechanically deformed, about the conductor 44 and conductor contact member 22 in order to provide good mechanical and electrical connection therebetween.

In order to provide additional strength to the tooth 28 of FIG. lit is possible to form a tooth such that it will have a rear supporting member which will also provide an additional cutting edge. Reference is now made to FIG. in which a tooth 50 has been skived in such a manner as to provide additional material for support, as at 52, which will take the shape of two generally triangular faces 54 meeting at the point 32 and extending into the recess 56. As a result an additional cutting edge 58 will be provided extending from the point 32 in the general direction of the recess 56. As is shown in FIGS. 4 and 5 the

teeth

28 and 50 have been struck in such a manner that the cutting edges 38 lie along a single plane. However, if desired, tooth 60 as is shown in FIG. 6, may be created in such a manner as to place cutting edges 62 in planes different from one another. As is shown in FIG. 7, teeth 64 have been formed such as to have serrated edges 66 in order to better grip the conductor and to prevent it from being'withdrawn from the connector. In addition, if it is desirable to employ a compound to prevent oxidation of the conductor. once the same has been crimped to the connector a series-ofrecesses 68 are valuable for retaining such compound and preventing the same from being removed from the connector. In general the tooth 64 may be created by first scoring the planar surface of the conductor contact member with a series of recesses such as 68. The teeth 54 are then skived from the conductor contact member to provide teeth 64 having serrated edges 66 as shown in FIG. 7.

In order to eliminate the necessity of a separate coupling means such as a sleeve 46 of FIG. 2, the conductor contact member may be preformed to facilitate its use both as the conductor contact member and also as the coupling means for coupling the connector to the conductor. As is shown in FIG. 8 connector 70 has a conductor contact member 72 formed in a generally U-shaped manner being lined for at least a portion of its internal surface with a series of teeth 74. Coupled to the conductor contact member 72 is, a tongue 76 having placed therein an aperture 78 for the receipt therethrough of a terminal screw. A conductor (not shown) will be inserted in the U-shaped channel of the conductor contact member 72 in the direction generally shown by the arrow and then the upstanding arms 80 will be mechanically deformed about such conductor in order to ensure mechanical and electrical contact between the connector 70 and the conductor. As is shown' in FIG. 9, upstanding arms 80 will be rolled to seal about conductors such as 82. Alternatively they may be rolled in a single, either butt or overlapped configuration, about a single conductor. As can be seen from FIG. 9 the teeth 74'bite through the insulation 84 of the conductor 82 and enterinto the metal of the conductor.

Further, it should be noted that the teeth 74 are arranged along the conductor contact member 72 in rows such as rows A, B and C and columns such as D, E and F to provide a more random pattern and to ensure that the teeth 74 will adequately seize the conductor to thus ensure a good electrical and mechanical coupling therewith. It should be noted that the teeth 74 of the row B and of each succeeding even numbered row are offset by approximately one-half column spacing of the teeth 74 in row A. Any convenient offset may be employed to thus ensuremaximum gripping of the teeth 74 into the conductor placed within the conductor contact member 72.

To this point the connectors have been shown to employ a tongue for connection of the conductor and connector to a further electrical assembly. As is shown in FIGS. 10 and 11 such utilization of a tongue member is not necessary in order to use the instant connector to join a conductor to a further electrical assembly. As is shown in FIG. 11 connector'90 is employed to connect the conductor 92 to a bus bar 94 by means of a fastening means 96. As is better shown in FIG. 10, connector of FIG. 11, has its conductor contact member 98 formed in a generally L-shape with a plurality of teeth 100 lining the inner surface of the connector 90.

Apertures

102 and 104 are provided through the legs of the conductor contact member 98 in order to receive a fastening means such as 96 of FIG. 11 therethrough.

Further, it is possible to directly couple conductors without a fastening means such as the fastener 96. Such arrangements are shown in FIGS. 14 and 15 respectively. In FIG. 15 a cylindrical splicer 119 is shown having a plurality of teeth 112 along at least a portion of the inner surface thereof. Conductors will be inserted from either, or both, ends of the open cylindrical connector and then the connector 110 will be applied to the conductors by an externally applied crimping force by a tool (not shown). As is shown in FIG. 14, the connector 120 is generally of a rectangular configuration and has upon the inner surfaces of its upper member 126 and its lower member 124a series of teeth 126. Accordian like sides 128 permit the connector 120 to be closed about conductors inserted from either, or both, of the open ends to permit the connector 120 to be crimped to such conductors when subjected to an externally applied crimping force.

With multiple conductors, in order to ensure maximum penetration of the insulation thereof it may be desirable to replace the conductor contact member 22 of FIG. 1 with a conductor contact member 130 of FIG. 13. Conductor contact member 130 of FIG. 13 has teeth 134 on a first surface thereof and additional teeth 136 on a second surface opposite the first. Conductors may then be placed in contact with the teeth 134 and the additional teeth 136, and a sleeve such as the sleeve 46 of FIG. 2, may then be employed to couple conductor contact member 130 to the conductors. In addition to crimping, or mechanically deforming, the conductor contact member or a sleeve about the conductor contact member and a connector it is also possible, by mechanical deformance, which does not distort the overall connector, to employ the teachings of the instant invention.- Turning now to FIG. 12 there is shown a tap 140 having a body portion 142, a saddle 144, which can be moved relative to conductors placed therein by means of a screw 146. Conductor contact member 148, having a generally U-shape, and having teeth 150 on a first surface thereof and teeth l52on a second surface thereof is inserted between

conductors

154 and 156. The application of tightening forces to the screw 146 will bring the saddle 144 to bearupon the conductor 154 which in turn will force the conductor 154 to bear against the teeth 150 of the conductor contact member 148. This in turn will bring teeth 152 on the lower portion of the conductor contact member 148 into contact with the conductor 156 and force the same to the bottom of the body 142, providing a good mechanical electrical coupling between the

conductors

154 and 156 and the connector 140.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiments, it will be understood that various omissions and substitutions and changes of the form and details of the devices illustrated and in their operation may be made by those skilled in the art, without departing from the spirit of the invention. 1

lclaim:

1. An insulation piercing connector for making an electrical contact through the insulation of an insulated conductor comprising: conductor contact means arranged to be positioned adjacent an insulated conductor; a plurality of teeth on at least a portion of said conductor contact means positionable adjacent the insulation of an insulated conductor; coupling means adjacent said conductor contact means and positionable about an insulated conductor for bringing said teeth of said conductor contact means into intimate contact with an insulated conductor positioned adjacent said conductor contact means; said teeth being struck from a first surface of said conductor contact means and having a point and at least two cutting edges extending therefrom; the longitudinal axis of said teeth being disposed substantially normal to the plane of said conductor contact means; a first portion of the surface of each of said teeth is comprised of two planar regions meeting in a third-cutting edge extending to said point; and a plurality of recesses, one for each tooth adjacent its associated tooth.

2. A connector, as defined in claim 1, wherein a further portion of the surface of each of said teeth is conical and further comprises a plurality of recesses extending along said conical surface of each of said teeth, said recesses intersecting said two cutting edges whereby said two cutting edges are serrated.

4. A connector, as defined in claim '3, wherein the teeth in the second and each succeedingeven row are offset with respect to the column spacing of the teeth in the odd rows.

5. A connector, as defined in claim 1, wherein each of said teeth are composed of material harder than said conductor contact means.

6. A connector, as defined in claim 1, wherein said conductor contact means has formed therein coupling means for coupling to an electrical terminal.

7. A connector, as defined in claim 1, wherein said coupling means is a deformable sleeve arranged to be deformed by an externally applied force whereby said insulated conductor is coupled to said conductor contact means and said teeth pierce the insulation of said conductor.

8. A connector, as defined in claim 1, wherein said conductor contact means has formed therein at one end thereof an electrical contact coupling means for coupling to an electrical terminal.

9. A connector, as defined in claim 1, further comprising: a plurality of additional teeth struck from a second surface of said conductor contact means.

10. A connector, as defined in claim 1, wherein said conductor contact means is folded along one dimension whereby said teeth extend along both exposed surfaces of said folder conductor contact means.

11. A connector, as defined in claim 1, further comprising a plurality of second recesses, one for each tooth; said second recesses each being located in a portion of the surface of its associated tooth; and two additional cutting edges for each tooth partially defining each of said second recesses.

12. An insulation piercing connector for making an electrical contact through the insulation of an insulated conductor comprising: conductor contact means arranged to be positioned adjacent an insulated conductor; a plurality of teeth on at least a portion of said conductor contact means positionable adjacent the insulation of an insulated conductor; coupling means adjacent said conductor contact means and positionable about an insulated conductor for bringing said teeth of said conductor contact means into intimate contact with an insulated conductor positioned adjacent said conductor contact means; said teeth being struck from a first surface of said conductor contact means and having a point and at least two first cutting edges extending therefrom and defining a first surface of said tooth; the longitudinal axis of said teeth being disposed substantially normal to the plane of said conductor contact means; a plurality of first recesses, one for each tooth, adjacent said first surface of its associated tooth; a plurality of second recesses, one for each tooth; said second recesses being located in a second surface of its associated tooth; and at least two second-cutting edges for each tooth partially defining each of said second recesses.

13. A connector, as defined in claim 12, wherein said second surface is conical and further comprises a plurality of recesses extending along said conical surface of each of said teeth, said recesses intersecting said two first-cutting edges whereby said two first-cutting edges are serrated.

14. A connector, as defined in claim 12, wherein said teeth are arranged in rows along the length of said conductor contact means and columns along the width thereof.

15. A connector, as defined in claim 12, wherein said conductor contact means has formed therein coupling means for coupling to an electrical terminal.

16. A connector, as defined in claim 12, wherein said coupling means is a deformable sleeve arranged to be deformed by an externally applied force whereby said insulated conductor is coupled to said conductor contact means and said teeth pierce the insulation of said conductor.

- 17. A connector, as defined in claim 12, further comprising: a plurality of additional teeth struck from a second surface of said conductor contact means.

18. A connector, as defined in claim 12, wherein said conductor contact means is folded along one dimension whereby said teeth extend along both exposed surfaces of said folded conductor contact means.

19. A connector, as define d in claim 12, wherein said first surface of said tooth is comprised of two planar regions meeting in a third-cutting edge extending to said point.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,549,786 Dated December 52, 1970 Inventor s) Lai Che Kuo It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 66, after "10" insert applied Column 4, line 18, "54" should be 64 Column 6, line 24, "folder" should be folded Signed and sealed this 11th day of May 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SGHUYLER,

Commissionerof Paten- Attesting Officer