GB2100529A

GB2100529A - Method of terminating an electrical conductor to a contact member

Info

Publication number: GB2100529A
Application number: GB8201507A
Authority: GB
Original assignee: Bunker Ramo Corp
Current assignee: Bunker Ramo Corp
Priority date: 1978-04-17
Filing date: 1979-03-30
Publication date: 1982-12-22
Also published as: SE7903165L; CA1115371A; JPS54158689A; PL214884A1; DK150179A; GB2019119B; GB2019119A; IL56995A0; NL7902956A; BE875636A; GB2100529B; FR2423880A1; BR7902191A; DD143129A5; IT7921907A0; AU4588679A; IT1112208B; DE2913799A1; ZA791746B

Abstract

A conductor 12 is inserted into the terminal portion 28 of a contact member and is electrically engaged by elements 37, 36. Segments 38 of the contact member distinct from the elements 37, 36 are then crimped on to the conductor to mechanically retain the conductor in electrical engagement with the contact member. The contact member may be premounted in a dielectric body 14. A combined insection and crimping tool 42, 44 may be used. The segments 38 are sheared from the walls 32, 34 of the terminal portion 28. <IMAGE>

Description

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GB 2 100 529 A 1

SPECIFICATION

Method of terminating an electrical conductor to a contact member

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The present invention relates to a method of terminating an electrical conductorto a contact member, employing solderless electrical connections, more particularly (but not exclusively) insulation-piercing 10 electrical connections.

In recent years, increasing number of applications have developed in the communications, data processing and transportation industries requiring electrical conductors which provide reliable solderless 15 interconnections with insulated electrical conductors. This demand has perhaps been greatest in the telecommunications industry where miniaturized, high contact density ribbon connectors are used extensively. Connectors of this general type are 20 disclosed in United States Patent Nos 3,867,005; 3,902,154 and 3,926,498. Because of the great number of individual conductors terminated in these connectors and because of the close spacing between the individual contacts, reliable solder termi-25 nations are difficult to achieve, as well as time consuming and costly to maintain and service. For these reasons insulation-piercing contacts have been developed for use in ribbon connectors and have met with wide acceptance when used to 30 terminate insulated conductors having solid wire cores. Unfortunately, due to the demanding standards in the industry requiring almost negligible change in contact resistance, the insulation-piercing type ribbon connectors have proven unacceptable 35 when used with stranded wire core conductors. Experience has shown that tensile forces applied to the conductors, as well as the cold flow of the insulation surrounding the core, causes the individual strands of the wire core to move and reposi-40 tion within the insulation-piercing contacts, causing changes in contact resistance. Thus, solder termination ribbon connectors are still used with standard core insulated conductors.

Accordingly, a need exists for an improved 45 method of termination with the electrical contact premounted within the connector.

The present invention therefore provides a method of terminating an electrical conductorto a contact member premounted in an electrical connec-50 tor and having a terminal portion including at least one conductor engaging element, the method comprising the steps of inserting the conductor into the contact member to seat the conductor within the terminal portion and make electrical engagement 55 between the conductor and the said element, and thereafter crimping a segment of the contact member terminal portion otherthan the element on to the conductorto mechanically retain the conductor in electrical engagement with the contact member. The 60 method may be employed to effectively and reliably terminate both solid and stranded wire core insulating conductors in an insulating-piercing contact, without the need for any soldering operation, and while the contacts are assembled within the con-65 nector.

The invention will be described in more detail, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a side elevational view of an electrical 70 connectorfor use in practising the present invention and showing the individual conductors of a multi-conductor electrical cable terminated therein;

Figure 2 is a fragmentary perspective view of the connector of Figure 1 with portions broken away to 75 illustrate the crimp-pierce termination obtained with the connector;

Figure 3 is a fragmentary cross-sectional view illustrating the sequence of steps performed to obtain the desired crimp-pierce termination; 80 Figure 4 is a perspective view illustrating a termination tool;

Figured is a plan view of the terminal portion of a preferred contact member used in the connector illustrated in Figure 1; and 85 Figure 6 is a perspective view of the contact member of Figure 5.

With reference to the drawings, and specifically Figure 1, an electrical conductor 10 is shown with individual insulated conductors 12 terminated to 90 each of the connector's electrical contacts. The connector 10 is a ribbon connector and comprises a dielectric insert 14, a plurality of electrical contacts 16 mounted in the insert, and a metal skirt 18 which houses the insert and contacts subassembly. A 95 detailed description of the structure and function of ribbon connectors and their components is provided in U.S. Patents Nos 3,867,005 and 3,926,498 the disclosures of which are incorporated herein by reference. The insert 14 includes a plurality of 100 elongated contact-receiving cavities 20 and an access passageway in the form of a slot 22 extending transversely to the cavities 20. The slot 22 provides access to the electrical contacts 16 to permit crimp-pierce termination of the conductors 12 as described 105 in greater detail below.

Referring now to Figure 2, the subassembly comprising insert 14 and contacts 16 is shown in greater detail. The insert includes a plurality of partitions or upstanding barriers 24 which form the sides of the 110 contact-receiving cavities 20. Each of the contacts 16 has an active contact portion 26 adapted to electrically engage a compatible contact and a terminal portion 28 for electrically and mechanically engaging the insulated conductors 12. In the illustrated 115 embodiment, the terminal portion 28 of each contact is channel-shaped, having a bottom wall 30 and opposed side walls 32 and 34, and includes insulation-piercing means which serve to provide the electrical and mechanical engagement with a con-120 ductor inserted and pressed into the channel.

The insert 14 is designed to permit crimping of the terminal portion 28 while the contacts 16 are mounted in place in the connector. To accomplish this end, the slot 22 is formed in each barrier 24 to 125 provide access for a crimping tool. The slot 22 need not extend to the base of cavity 20 but must terminate at a point below the top of the side walls 32 and 34 of the contact terminal portion 28. In other words, the side walls 32 and 34 extend upwardly into 130 the slot 22. As shown in Figure 3 the crimp tool is

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GB 2 100 529 A

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inserted into the cavity 20 along a path of travel generally perpendicularto the terminal portion 28 and acts to deform a portion of the side walls 32 and 34 coincident with the slot 22 to hold the conductor 5 12 in final terminated position.

A preferred configuration forthe terminal portion 28 is illustrated in Figures 3,5 and 6. In accordance with this embodiment, the side walls 32 and 34 include conventional insulation-piercing protuber-10 ances or detents 36 whose structure and function are well known in the art. In addition, the terminal portion 28 of the contact includes a further insulation-piercing extrusion in the bottom wall 30. In the illustrated embodiment, the extrusion is an upstand-15 ing cone 37. The side walls also include inwardly extending, offset upper edges 38 which form a lead-in for the crimp tool. The detents 36 are positioned longitudinally on the sidewalls 32 and 34 remote from the slot 22 of insert 14 and their 20 function and operation remain substantially the same as in prior art connectors. The cone 37 and edges 38 are positioned coincident with the slot 22 and serve to improve both the mechanical and electric characteristics of the termination. As the 25 conductor is pressed into the terminal portion of the contact, the cone 37 pierces the conductor's insulation and engages the conductor core. Likewise, as the walls 32 and 34 are deformed by the crimp tool, the edges 38 pierce the conductor's insulation and 30 also engage the conductor core. Thus, in the illustrated embodiments electrical contact is made at the sides, top and bottom of the conductor via the detents 36, cone 37 and edges 38. In addition, mechanical retention of the conductor within the 35 contact is enhanced, and the opportunity for movement of even stranded core conductors is thereby minimized.

A preferred termination tool is illustrated in Figure 4 and includes a bifurcated termination head 40 40 having separate insertion and crimping members, 42 and 44, respectively. The insertion member 40 has a generally planar end face 46 for engaging and pressing the conductor into electrical engagement with the terminal portion 28 of the contact 16. The 45 crimping member 44 has a specially configured end face 48 including means for cutting portions of the contact's side walls 32 and 34 and means for crimping or folding these cut portions inwardly onto the conductor. In the illustrated embodiment, the 50 cutting means are curved edges 50 which shearthe side walls of the contact as the tool is inserted into the cavity 20, and the folding means are the curved surfaces 52 which meet at a central apex 54. It will be appreciated that as the insertion tool is inserted into 55 cavity 20 to the full extent, the surfaces 52 will direct the cut portions of side walls 32 and 34 over and into the conductor, thereby crimping the contact and conductor in a fixed insulation-piercing termination.

In a conventional ribbon connector as many as 60 twenty-five conductors will be terminated to twenty-five separate contacts on each side of the connector. Each of the conductors is aligned adjacent the terminal portion of a respective contact and then terminated by means of a suitable termination tool. 65 The sequence of steps employed to effect a crimp-

pierce termination with the described connector and tool are illustrated in Figure 3. After the conductors have been aligned adjacent the appropriate contact terminal portions 28, the tool carrying head 40 70 presses each conductor into the terminal portion and then crimps the contact onto the conductor. Since the tool moves relative to the connector (rightto left in Figure 3) with each insertion, the insertion member 42 first seats the conductor within the contact 75 and properly positions the conductor for the subsequent insertion of the crimping member 44. As can be clearly seen in Figure 3 the crimping member 44 extends laterally beyond the side walls 32 and 34 of the contact, thereby necessitating the access pas-80 sageway or slot 22. The slot 22 must have a depth sufficientto allow full insertion of the crimping member 44 to properly sheet the side walls 32 and 34 and completely crimp the sheered portions over and into the conductor.

85 Of course, it should be understood that various changes and modifications to the preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and 90 scope of the present invention and without diminishing its attendant advantages. It is, therefore, intended that such changes and modifications be covered by the following claims.

Claims

95 CLAIMS

1. A method of terminating an electrical conductorto a contact member premounted in an electrical connector and having a terminal portion including at

100 least one conductor engaging element, the method comprising the steps of inserting the conductor into the contact member to seat the conductor within the terminal portion and make electrical engagement between the conductor and the said element, and 105 thereafter crimping a segment of the contact member terminal portion other than the element on to the conductorto mechanically retain the conductor in electrical engagement with the contact member.

2. A method according to claim 1, wherein the tool simultaneously shears and folds over the tabs from opposed further portions of the two sidewalls. 15

3. A method according to claim 2, wherein each tab is flanked by two of the indented insulation piercing portions.

Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1982.

Published by The Patent Office, 25 Southampton Buildings, London, WC2A1 AY, from which copies may be obtained.

2. A method according to claim 1, wherein the 110 crimping step comprises shearing the said segment from a wall of the terminal portion and deforming the segment on to the conductor.

3. A method to claim 2, wherein the terminal portion comprises a generally U-shaped channel and

115 the conductor engaging element comprises a pair of detents extending inwardly from opposing sidewalls of the channel, and the crimping step includes shearing the said segment from at least one of the sidewalls.

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4. A method according to claim 3, wherein a segment is sheared from both sidewalls.

New claims filed on 11 August 1982 Superseded claims 1 to 4 125 Newclaims:-

1. A method of terminating an insulated electrical conductor in a channel-shaped terminal portion of a contact member premounted in an electrical 130 connector, the channel-shaped terminal portion hav-

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ing two sidewalls with opposed, indented insulation piercing portion comprising the steps of pushing the conductor into the contact member to seat the conductor within the terminal portion and make 5 electrical engagement between the conductor and the insulation piercing portions, and thereafter applying a tool to a further portion of at least one sidewall adjacent the insulation piercing portion, so as to crimp a retaining tab over the conductor by 10 simultaneously shearing the tab from the sidewall and folding the tab in over the conductor.