GB1570190A - Electric connectors - Google Patents

Description

PATENT SPECIFICATION

( 11) ( 21) Application No 1700/77 ( 22) Filed 2 Feb 1976 ' ( 62) Divided out of No 1 570 189 ( 23) Complete Specification filed 2 Feb 1977 > ( 44) Complete Specification published 25 June 1980 : ( 51) INT CL 3 H Oi R 4/10, 23/22//13/46 _ ( 52) Index at acceptance H 2 E 10 B 1 B i F 30 3 A 10 B 3 3 A 13 3 A 1 3 A 2 3 B 6 3 C 2 A 3 C 2 C 3 D 10 3 D 3 3 E 7 ( 72) Inventor DEREK RUSHTON ( 54) IMPROVEMENTS IN ELECTRIC CONNECTORS ( 71) We, BIGC-BURNDY LIMITED, a British Company, of Parr, St Helens, Merseyside WA 9 l PR, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly

described in and by the following statement:-

This invention relates to electric connectors and methods of making them More specifically it relates to connectors including a row of contact elements each having at least one contact finger (usually a pair of fingers) that flexes in a particular plane (towards and away from one another in the case of paired fingers) to provide or transmit contact pressure to a mating contact The invention is primarily (but not exclusively) concerned with connectors suitable for engaging mating contacts formed directly on the edge of a printed circuit D 0 board (edge connectors).

It is essential in the case of an edge connector and desirable in many other cases for the direction of flexing of the finger or fingers to be perpendicular to the length of the row of contact elements, and with currently available designs of contact element this has caused difficulties when it was desired to connect a wire or other conductor to the contact element by crimping (compression jointing), as it has been necessary to handle the contact elements individually in order to get the necessary access for the crimping tools.

In accordance with one aspect of the present invention, an electric connector includes a row of contact elements each having at least one contact finger that flexes in a respective reference plane perpendicular to the row of contacts to provide or transmit contact pressure to a mating contact when the connector is engaged with a row of such contacts and has a conductor secured to each contact element by a crimped joint that has been compressed between a pair of dies moved towards one another in the respective reference plane.

In accordance with another aspect of the invention, a method of making an electric connector comprises forming from sheet metal a row of contact elements each having at least one contact finger that flexes in a respective reference plane perpendicular to the row of contacts and a crimping socket, inserting a conductor in each crimping socket, and compressing the socket between a pair of dies moving towards one another in the respective reference plane.

The socket may be of the well-known opensided type with a U-shaped cross-section oriented with the centre-line of its base and the mid-line of its open side in the respective reference plane.

The axis of the crimping socket and of the eventual crimped joint will almost invariably lie in the reference plane, and in most cases it is preferably coincident with or parallel to the axis of the contact finger Other orientations may however be used and for some applications it may be preferable for the socket axis and the finger axis to be perpendicular to one another but still both in the reference plane, forming a "flag type" contact element.

Preferably a series of the contact elements are produced from a strip of metal and the elements remain connected together by a "selvage" of the strip, which is preferably perpendicular to the reference plane, until the elements have been at least partially inserted into an insulating housing and/or the conductors have been crimped to the elements.

Since the crimping dies move perpendicular to the axis of the strip this presents no access problems If desired, all the crimps of a connector can be effected simultaneously using a multiple crimping tool or a row of tools in a single press of relatively large capacity, or the connector or strip of contacts (as the case may be) may be indexed (moved stepwise) to present each contact element in turn to a single crimping station.

In a preferred technique, the contact elements of a series are connected at the free ends of the crimping sockets to a single selvage and are spaced along it at intervals corresponding to the spacing of the contact elements in the finished connector, or if that is impractic1570190 1,570,190 2 able a small multiple of that spacing The series is presented intact to an insulating body of the connector and the contact elements inserted part way into bores provided in the body so as to leave the crimping sockets projecting Conductor ends are introduced and crimping effected at this stage, and simultaneously or afterwards the selvage is cut away; and finally the contact elements pushed fully home into the body (Should the selvage prove an embarrassment in the crimping operation it may be removed before crimping provided that the insulating body holds the contact elements firmly enough to avoid accidental displacement) The invention will be further described, by way of example, with reference to the accompanying drawings in which:

Figure 1 is a longitudinal cross-section of a preferred form of connector in accordance with the invention; Figure 2 is a cut-away plan view of a part of the connector; Figure 3 is a portion of the cross-section on the line III-III in figure 1; Figure 4 is a diagrammatic isometric projection of the same connector showing two contact units only; Figure 5 is a longitudinal cross-section of the housing only of an alternative form of connector; Figure 6 is a front view of the housing shown in figure 5; Figure 7 is an end view and Figure 8 is a side view of a preferred design of contact element for either of the connectors; Figure 9 shows a blank for the contact element shown in figures 7 and 8; and Figure 10 is a cross-section through a crimped socket of a contact element showing also the dies by which it was crimped.

The connector of figures 1-4 includes an insulating body 1 made up of an upper member 2 and a lower member 3 which are stiff enough to be substantially rigid under conditions of use (in figure 2, the upper member 2 is omitted to show the internal structure more clearly) The upper and lower members 2 and 3 are connected together only by integral flexible but resilient bridges 4 (not visible in figure 1).

In alignment with the bridges 4 the upper and lower members are formed with ridges 5 to form between them a series of basically rectangular passages each of which receives a contact element 6 The contact elements will be more fully described below, but they consist basically of upper and lower contact portions 7,8 respectively, which bear on or lie close to the upper and lower walls of the contact passages, and a crimping socket 9 The contact element is inserted from the rear of the housing, that is the left-hand end as seen in figures 1 and 2, and is prevented from passing completely through the passage by abutments 65 near the front of the housing A shoulder 11, formed by the end of a slot 12 extending from the front of the housing, engages a resilient detent 13 to prevent unintentional withdrawal of the element; a releasing tool can 70 be introduced through the slot 12, if required, to release the detent 13.

A wedging member 14 is flexibly connected to the lower body member 3 by an integral hinge 15 When a connection is to be made, 75 this wedging member is arranged in the position shown in broken lines in figure 1, in which it exerts no appreciable force on, and will not necessarily touch, the upper body member 2.

A printed-circuit board 16 or other contact to 80 be engaged can then be inserted between the contact portions 7 and 8 without requiring any significant insertion force The wedging member 14 is now brought to the position shown in solid lines in which it engages the 85 contiguous rear end 17 of the upper member 2 and forces it away from the lower member 3, thereby flexing the bridges 4 and causing the front ends 18,19 of the upper and lower body members to approach one another, 90 thereby squeezing the contact portions 7,8 between them and increasing the contact pressure to an acceptable value To withdraw the board 16 or other contact, the wedging member is first returned to the release position 95 shown in broken lines, so that withdrawal also requires no substantial force By avoiding large insertion and withdrawal forces, the risk of damaging contacts is considerably reduced.

The alternative design shown in figures 5 100 and 6 incorporates two independent modifications (either of which can be used separately) First, the wedging member 20 is separate from the body 1, and the rear end parts 21,22 of the upper and lower members 105 2,3 are alike; this simplifies manufacture but has the disadvantage that the wedge member may be forgotten during the initial stages of assembly Secondly the slot 12 (figures 1-4) is replaced by an aperture 23 of square or 110 other suitable cross-section opening to the top of the housing.

Figures 7-10 illustrate a preferred design of contact element for either of the connectors described This is formed from sheet metal by 115 conventional techniques The contact portions 7 and 8 and crimping socket 9 have already been briefly referred to.

The contact portions 7 and 8 are alike and are each pressed to form stiffening sidewalls 120 24, a tapered lead-in zone 25, and a contact dimpel 26 The contact portions are connected by flexible arms 27,28 to a channel section central support 29, one limb of which provides the resilient detent 13 already described The 125 crimping socket 9 is of the open-sided type and includes a contact-making section 30 for engaging the bared end of an insulated wire 1,570,190 and a gripping section 31 for engaging the insulation remaining on the wire Figure 9 shows the blank from which the contact element is to be made, as initially stamped out but before pressing and bending; the reference numerals in this figure correspond (where applicable) to the parts of the element that will be formed by the various parts of the blank The blanks are connected together for ease of handling by "selvages" 32,33 for as long as possible, and in particular the selvage 32 remains in place when the contact elements are otherwise finished The spacing of the contact elements along the selvage is i three times the spacing of the bores in the connector body as the width of the blank precludes a spacing that is the same as or only twice that of the bores.

To make up a 14-contact connector, for ) example (as shown in figure 6) three strips of contact elements are cut, two carrying five contact elements each and the other only four.

The contacts of the first strip are introduced into the first, fourth, seventh, tenth and thirteenth bores, those of the second strip into the second, fifth, eight, eleventh and fourteenth, and those of the third strip into the third, sixth, ninth and twelfth The selvages of the three strips can be bent differently to avoid 0 interference between them, if required Initially the contact elements are inserted onlv until the detent 13 frictionally engages the insulating body, at which stage the entire crimping sockets 9 remain exposed behind the rear end of the insulating body.

Conductor ends are now introduced into and crimped in the sockets 9, either simultaneously using a large press or one by one using a small press, in either case using a pair of dies 34,35 (figure 10) that move vertically in the plane of figure 8; the contact elements are severed from the selvage 32, preferably simultaneously with the crimping operation but alternatively in a separate step (preferably after the crimping step but if necessary before it) The contact elements, with the conductors now attached, can then be pushed fully home until the detent 13 engages the shoulder 11 to complete the connector; no rotation of any of the components is required.

The connectors shown in figures 1-6 are also claimed in our Application No 4014/76 (Serial No 1 570 189).

Claims (1)

1. WHAT WE CLAIM IS:-

   1 An electric connector including a row of contact elements each having at least one contact finger that flexes in a respective reference plane perpendicularly to the row of contacts to provide or transmit contact pressure to a mating contact when the connector is engaged with a row of such contacts and having a conductor secured to each contact element by a crimped joint that has been compressed between a pair of dies moved towards one another in the respective reference plane 65 2 An electric connector as claimed in claim 1 in which the elements each have a pair of contact fingers that flex towards and away from one another in the respective reference olane 70 An electric connector as claimed in claim 1 or claim 2 in which the axis of the crimped joint is coincident with or parallel to the axis of the contact finger or contact fingers.

   4 An electric connector substantially as 75 described with reference to the drawings.

   A method of making an electric connector comprising forming from sheet metal a row of contact elements each having at least one contact finger that flexes in a respective 80 reference plane perpendicular to the row of contacts and a crimping socket, inserting a conductor in each crimping socket, and compressing each socket between a pair of dies moving towards one another in the respective 85 reference plane.

   6 A method as claimed in claim 5 comprising forming each contact element with a pair of contact fingers that flex towards and away from one another in the respective 90 reference plane.

   7 A method in accordance with claim 5 or claim 6 in which the axis of the crimping socket is coincident with or parallel to the axis of the contact finger 95 8 A method in accordance with any one of claims 5-4 in which a series of contact elements is formed from a strip of metal and the elements remain connected together by a selvage of the strip until the elements have 100 been at least partially inserted into an insulating housing and/or the conductors have been crimped to the elements.

   9 A method in accordance with any one of claims 5-8 in which: a series of contact 105 elements is formed from a strip of metal and the elements are connected at the front ends of the crimping sockets to a single selvage of the strip and are spaced along the selvage at intervals corresponding to the spacing of the 110 elements in the finished connector or to a small multiple of that spacing; the series is presented intact to an insulating body of the connector and the contact elements inserted part way into bores provided in the body so 115 as to leave the crimping sockets projecting; conductor ends are introduced and crimping effected at this stage; the selvage is cut away after the contacts have been inserted part way into the body; and finally the contact elements 120 are pushed fully home.

   A method as claimed in claim 9 in which the selvage is cut away simultaneously with crimping or afterwards.

   11 A method as claimed in any one of 125 claims 5-10, in which all the elements are crimped to respective conductors simul1,570,190 taneously using a multiple crimping tool or a row of tools in a single press.

   12 A method as claimed in any one of claims 5-10, in which the elements are crimned in turn at a single crimping station.

   13 A method of making an electric connector substantially as described with reference to the drawings.

   M J POOLE, Chartered Patent Agent, Bl CIC Limited, 38 Wood Lane, London W 12 7 DX.

   Agent for the Applicants (Under General Authorisation).

   Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1980.

   Published by the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.