US3601759A

US3601759A - Electrical connector

Info

Publication number: US3601759A
Application number: US797553A
Authority: US
Inventors: Randolph G Barker
Original assignee: Component Manufacturing Service Inc
Current assignee: Component Manufacturing Service Inc
Priority date: 1969-02-07
Filing date: 1969-02-07
Publication date: 1971-08-24
Anticipated expiration: 1988-08-24

Abstract

An electrical connector primarily for use in computer circuits having a pair of interengageable terminals. Each terminal has a plurality of aligned parallel-spaced contact elements insulated from each other with the spaces intermediate adjacent contact elements having a width sufficient to receive contact elements of the other terminal in electrical interengagement. Means for exerting a force normal to a parallel alignment of the contact elements are provided to compress the contact elements in the direction of the parallel alignment to effect positive electrical interengagement of the contact elements of one terminal with the contact elements of the other terminal.

Description

United States Patent [72} Inventor Randolph G. Barker Ranyham, Miss.

[21] Appl. Nov 797,553

[22} Filed Feb. 7, 1969 [45] Patented Aug. 24, 1971 [73] Assignee Component Manufacturing Service, Inc.

West Bridgewater, Mass.

[54] ELECTRICAL CONNECTOR 9 Claims, 36 Drawing Figs.

[52] US. Cl 339/59 M, 339/75 MP [51] Int. Cl H01r 11/02, HOlr 13/54 [50] Field of Search 339/18 B,

, 59 M, 75 M, 75 MP [56] References Cited UNITED STATES PATENTS 2,744,968 5/1956 Blackhall 339/75 M X 2,770,788 11/1956 Eschner... 339/75 M X 2,881,404 4/1959 Kamm 339/75 MP X 4/1960 Novak 4/1962 Germany Primary Examiner-Ian A. Calvert Ar10rney-Wolf, Greenfield & Sacks ABSTRACT: An electrical connector primarily for use in computer circuits having a pair of interengageable terminals. Each terminal has a plurality of aligned parallel-spaced contact elements insulated from each other with the spaces intermediate adjacent contact elements having a width sufficient to receive contact elements of the other terminal in electrical interengagement. Means for. exerting a force normal to a parallel alignment of the contact elements are provided to compress the contact elements in the direction of the parallel alignment to effect positive electrical interengagement of the contact elements of one terminal with the contact elements of the other terminal.

PATENTED AUG24 l97| SHEET 1 [IF 8 VENTOR.

SHEET [1F 8 PATENTEU M824 1911 PATENTED AUB24 197i SHEET 8 OF 8 PATENTEI] AUGZMHH SHEET 7 [IF 8 ELECTRICAL CONNECTOR SUBJECT MATTER OF INVENTION The present invention relates to an electrical connector and in particular to an electrical connector that is especially useful in compact and high-speed circuits.

BACKGROUND OF THE INVENTION Miniature circuits are especially desirable in computers and other apparatus requiring high-speed circuitry. To date computer connectors now commonly use a plurality of contact elements in the connector having 0.050 center to center contact spacing between adjacent contact elements. A spacing of 0.050 inches between adjacent contacts seems to be the minimum limit for designs heretofore used in connectors having resilient contact elements intended to provide a positive contact pressure in two mated terminals. Smaller center to center contact spacing preferably in the order of 0.025 inches is desirable, however, because of the high-speed circuitry developed for computer applications. Such small center to center spacing is difficult if not impractical using designs heretofore available.

SUMMARY OF INVENTION It is therefore an object of the present invention to provide an improved connector especially useful in high-speed circuitry. A further object of the present invention is to provide a connector that may utilize a 0.025 inch or less contact spacing between a plurality of adjacent parallel contacts. A still further object of the present invention is to provide an improved connector having good electrical contact in a design which may be varied both with respect to the size and shape of the contact elements themselves and the distance between contact elements. A further object of the present invention is to provide a versatile design that is adapted for use in a wide variety of electronic circuitry including computer circuits and other circuits useful in miniaturization. A further object of the present invention is to provide an improved connector having mating parts which may be readily interlocked in a firm electrical interengagement. A further object of the present invention is to provide a connector having mating parts that are adapted to be readily interengaged and securely locked with sufficient contact pressure to preclude inadvertent loosening due to vibrations and other extraneous forces.

In the present invention there is provided an electrical connector having a mating pair of interengageable terminals. Each terminal has a plurality of aligned parallel spaced contact elements with a space intermediate adjacent contact elements having a width adapted to receive a contact element of the other terminal. Means are provided for exerting a force normal to the parallel alignment of the contact elements when the contact elements are interengaged whereby the contact elements may be compressed in the direction of the parallel alignment to effect a positive electrical interengagement between the contact terminals through said contact element.

BRIEF DESCRIPTION OF DRAWINGS The foregoing objects and advantages of the present invention will be more clearly understood when considered in conjunction with the accompanying drawings in which FIG. I is a plan view of a male terminal embodying a part of the present invention FIG. 2 is a side elevation of the male terminal looking from the right of FIG. 1,

FIG. 3 is a plan elevational view of a female terminal adapted to be interengaged with the male terminal of FIG. 1,

FIG. 4 is a side elevational view ofthe female terminal looking from the left of FIG. 3;

FIG. 5 is a fragmentary plan elevational view on an enlarged scale of interlocked portions of the male terminal of FIG. 1 and the female terminal of FIG. 3,

ear-1 FIG. 6 is a plan view of a contact element used on the male terminal, 1

FIG. 7 is a side elevation of a contact element FIG. 6,

FIG. 8 is a plan view of a contact element used in the female terminal in FIG. 3,

FIG. 9 is a side elevation of the contact element of FIG. 8,

FIG. 10 is an exploded perspective view of a preferred embodiment of the invention with portions fragmented for clariy.

FIG. 11 is a side elevational view of a leaf forming a component of the embodiment of FIG. 10,

FIG. 12 is a top plan view of FIG. 11,

FIG. 13 is a top plan view of a leaf holder used in the embodiment of FIG. 10,

FIG. 14 is a side elevationalview of the holder shown in FIG. 13,

FIG. 15 is an end view ofthe holder of FIG. 13,

FIG. 16 is a top plan'view of a second leaf holder used in the embodiment of FIG. l0,

FIG. 17 is a side elevation of the holder of FIG. 16';

FIG. 18 is an end view ofthe holder ofFIG. 16,

FIG. 19 is a longitudinal side view of interengaged leaves and holders devoid of other elements showing the interengaged position of the two terminal halves when connected,

FIG. 20 is a perspective detail of an assembled leaf and printed circuit board illustrating a modification of the invention;

FIG. 21 is a detail of a further modification of the present invention;

FIG. 22 is a side elevational view of one of a pair of interlocking members illustrating -a further modification of the invention;

FIG. 23 is a top plan view of the element shown in FIG. 22;

FIG. 24 is an end view of the element of FIG. 22 looking from the right;

FIG. 25 is a fragmentary top plan view of components forming a further embodiment of the invention;

FIG. 26 is a side elevational view of the components of FIG. 25;

FIG. 27 is an end view looking from the right of one of the components of FIG. 25 along the line 27-27 thereof;

FIG. 28 is a fragmentary top planview of components of a further modification of the invention;

FIG. 29 is a side elevational view of the embodiment of FIG. 28;

FIGS. 30, 31 and 32 are each perspective fragmentary details illustrating modifications of means for-terminating the leaves herein described;

FIG. 33 is a perspective view of another embodiment of a terminal illustrating alternate means for connecting terminals to a circuit; I

FIG. '34 is a cross-sectional fragmentary detail on an enlarged scale of adjacent dividers in a terminal illustrating a further modification of a detail of the invention;

FIG. 35 is a perspective view of a further embodiment of the invention; and

FIG. 36 is a still further perspective view of a modification of the invention with portions broken away for clarity.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The embodiments of the present invention described in connection with the drawings are primarily useful in connection with compact and high-speed computer circuits. However,

other connector designs may be readily adapted embodying the present invention for circuits of other apparatus and for circuits for other uses. 7

In the embodiment described in FIGS. 1 to 9 there is illustrated a male terminal 1 (FIGS. 1 and 2) which is adapted to be electrically interengaged and mechanically interlocked with the female terminal 2 (FIGS. 3 and 4). The male terminal l is formed with a dielectric body 3 which may be molded or otherwise suitably formed. This body is preferably rectangular in shape having sidewallsS and 6 connecting the outer and inner walls 7 and 8 respectively, with major upper and

lower walls

9 and 10. A rectangular recess 12 extends from the inner wall 8 toward the outer wall 7 adjacent the upper wall 9. The recess 12 is spaced from the sidewalls and 6 and is designed to receive the inner ends of a plurality of parallel aligned spaced contact elements 14. These contact terminals preferably extend laterally across the male terminal with one end 15 of each longitudinally aligned in a plane spaced inwardly from the inner wall 8 within the recess 12. The other ends of the contact elements 14 are preferably arranged so that each alternate end 14A extends beyond the intermediate ends 148 to permit ease in connecting these terminals 14 to different leads and to permit these contact elements to be easily gang connected to suitable electrical circuitry.

The constructionof the contact elements 14 is best illustrated in FIGS. 6 and 7. In this arrangement each contact element is formed with a base 17 of insulating material that preferably has a resilience permitting repeated compression in the order of at least a few percent.

An insulating material as, for example, fiber glass has been found useful in connection with the embodiment described. Other suitable flat stock in the thickness required by the contact spacing may be used, including, for example, fiber, plastic, laminated Bakelite and'the like. The thickness and size of the contact elements may be varied depending upon the specific embodiment being fabricated. One surface 18 of each contact element has a conductive lead 19'formed on it. This conductive lead 19 may be formed in any suitable and conventional manner. The lead for example may be plated, silk screened, cemented or otherwise attached to the surface 18 of the flat insulating material 17. A suitable contact 20, made for example of gold or silver is suitably welded or attached to each lead 19. Preferably the leads [9 are formed on the base 17 with marginal insulating areas 22 extending lengthwise of the lead for the major portion of the contact element 14. A suitable hole 23 at the ends 14a, 14b of the contacts is used for attachment by suitable means of wires ofa circuit to which the connector is to be attached.

A slot 24 is formed between the

walls

9 and 10 and extends from the sidewall 6 to the recess 12. This slot 24 has a cam 25 journaled within it by a shaft 26 extending across the slot 24 from wall 9 to wall 10. The shaft 26 is suitably secured in the connector body 3. The cam 25 has a surface adapted to be rotated about the shaft 26 to move from within the slot 24 to project partially into the recess 12 and engage and exert a force on the aligned interengaging contact element 14 when the male and female terminals are interengaged. The cam may be integrally formed with lever 27 adapted to pivot the cam into and from a pressure engaging relationship with the contact elements 14. The lever 27 is positioned as illustrated in FIG. 1 when it is in nonpressure position.

The contacts 14 are spaced apart one from the other by suitable fillers 28 which may be integrally formed with the connector body 3. Preferably these fillers 28 are formed of the same type of material of which the insulating portion of the contact elements 14 are formed.

Projecting perpendicularly from the inner wall 8 are the guide pins 30 and 31. Guide pins 30 may be of smaller crosssectional diameter than guide pins 31. Guide pin 31 is symmetrically arranged with respect to the walls 9 and I0 and guide pin 30 is arranged closer to wall 10 than wall 9.

The female contact terminal 2 is formed with a moulded body 40. This moulded body preferably has sidewalls 41 and 42 an inner wall 43 and outer wall 44 of a height equivalent to the height of the

walls

5, 6, 7 and 8. The length of

walls

43 and 44 are preferably equal to the length of the walls 7 and. 8. The outer portion of the body 40 beyond shoulder 46 is thinner than the inner portion. Thus the thickness of the body 40 is the full height of the

walls

41, 42 and 43 in the portion 48 of the body 40. The portion 49 however is the thickness of only the height illustrated in dotted outline at 50. A plurality of aligned parallel spaced contact elements 51 project from the inner wall 43 to a common plane 53. The outer ends of the contact elements 51 are staggered so that alternate ends 51A project beyond the intermediate ends 518. The contact element 51 are spaced uniformly apart. by fillers 54 that have a thickness equal to the thickness of the contact elements 14 to permit an interleaving of the

contacts

14 and 54 when the terminals are interengaged. Preferably fillers 54 are made of a material similar to the fillers 28.

The construction of each contact element 51 is best illustrated in FIGS. 8 and 9. A dielectric insulating base 54'is of a size and shape similar the dielectric insulating base 17. One end of this dielectric insulating base 55 may be tapered to permit easy interengagement. One surface of base 54 has formed on it a contact or lead 56 of suitable conductive material which may be formed on the surface 54 in a manner similar to the lead 19. An aperture 57 is formed at the other end of the contact element to which may be attached leads or other circuitry elements. The contact elements 51 each have some flexibility and preferably some of compressibility and resilience. The amount of flexibility and resilience should be sufficient to accommodate the manipulations of the device when it is interengaged with the male terminal in a manner as hereinafter described.

The female terminal is formed with openings or

holes

60 and 61 located on wall 43 with a diameter and depth to receive respectively the

pins

30 and 31.'The recesses 60 and 6larespaced from the contact elements 54 at a distance adapted to stagger the elements 54 relative to the contact elements 14 when the male and female terminals are interengaged. Thus contact elements 54 are presented to the spaces intermediate the contact elements 14 when the terminals are interengaged.

When the terminals are interengaged in a manner as frag mentarily illustrated in FIG.- 5, the cam lever 27 may be rotated from the position illustrated in FIG. 5 at 27A which is a nonlocking position to the position illustrated in solid outline which is a locking position. When the cam lever 27 is thus rotated the cam 25 exerts a pressure parallel to the longitudinal alignment of the

interengaged contact elements

51 and 14. The pressure that may be applied by the cam 25 may be varied and is dependent upon the amount of tension applied by the camming action and by other variables, including for example, the degree of compressibility and flexibility of the various contacting elements. However if a force of 4 ounces is applied by the camming action a similar amount of pressure is applied to each contact in the series. Thus interengaged leads 19 and 56 may be electrically closed in a series of parallel electrical connections through contacts 20. The locking of the camming action in the position illustrated in solid outline in FIG. 5 also functions to mechanically lock the terminals in rigid engagement until the cam is returned to release position 270.

Referring now to the embodiments illustrated in'FIGS. 10 to 19 there is shown a connector which is particularly useful for very small or high-density applications. This construction can be used for comparatively small applications and may, as

v hereafter described, be modified in a number of ways for uses in printed circuits, integral connection to cables in shielded circuits and for a wide variety of other highly critical uses. the construction has advantages in assembly since the various components can be comparatively easily assembled with the I contact leads individually welded or soldered to cables, wires or circuit board in an individual and simplified fashion. Further, the reduced number of different types of elements in the connector reduces costs of manufacture. Connectors made in accordance with the embodiment illustrated are not likely to become defective, are easy to connect and disconnect and assure a positive spring action connection between adjacent contact leads.

Referring to FIG. 10 of the drawings there is illustrated a pair of leaf holders and 101 which differ slightly in construction from each other. These

leaf holders

100 and 101 are each designed to have cemented to them in parallel spaced relationship respectively contact leaves 102 and 103 with the contact leaves 102 and 103 preferably identical in construction to each other. The leaf holder 101 is best illustrated in FIGS. 13 to inclusive. This holder is formed of an integral dielectric board preferably having a rectangular dimension as illustrated in FIG. 13. The holder 101 is formed with

opposite faces

104 and 105. A pair of grooves or slots 107 extend parallel to one another across the face 104. These slots 107 are uniform in width and depth and in the example illustrated in which the holder has an overall length of 1.180 inches, the slots 107 may have a width of 0.062 inches and a depth of 0.015 inches with the slots located an equal distance from opposite ends. Also projecting from the face 104 are a plurality of dielectric dividers or insulators 110. These dividers preferably have a height of in the order of 0.070 inches in the specific embodiment illustrated and a length in the order of 0.228 inches. The dividers are parallel to one another are marginally spaced from one end 111. The dividers 110 define a plurality of channels 112 within which the leaves are secured. The channels 112 are preferably of a thickness of in the order of 0.013 inches, while the dividers have a thickness of the order of 0.012 inches. In the specific embodiment illustrated there are provided 25 channels 112 intended to receive 25 leaves of the type illustrated in FIGS. 11 and 12.

The leaves 103 which are secured within the channels 112 are formed with a dielectric base 115 that has an overall length preferably in the order of 0.625 inches for the embodiment described, and an overall height of in the order of 0.070 inches. Projecting from one side edge of the dielectric base is a tab 116 integrally formed with the base and having a dimension in the order of 0.062 inches in length and no more than 0.015 inches in height. The tabs 116 are intended to be engaged by one of the slots 107 when the leaves are secured to the leaf holder 101. A conductive layer which may be formed by any suitable metal deposition technique is formed on both sides of the dielectric base 115 to form conductive terminals 118. Preferably these conductive terminals or layers 118 are marginally spaced from the opposite side edges of the dielectric base 115 and are provided with enlarged bulges or end portions 119 to facilitate terminal connections. The width of the conductive terminals or leads 118 may be in the order of 0.032 inches while the end portions 119 may, for example, have a diameter of 0.050 inches. The terminals 118 are preferably formed on both sides of the base 115. Twenty-five leaves are secured to the leaf holder 101 with each leaf having its tab 116 positioned in channel 107 close to the dividers 112 and with each leaf separated one from the other by the dividers 112. The leaves 103 have one end 121 terminating adjacent to the end 111 of the holder 101. The other ends 122 of the leaves 103 terminate intermediate the channels 107.

The holder 101 is secured within the bottom 130 of a metal cover. The bottom 130 has a bottom wall 131 and two integrally formed sidewalls 132 and 133 at opposite side edges integrally connected to the bottom 131. The sidewalls 132 are formed with apertures 134 designed to receive a spring member, hereafter described. These apertures 134 are aligned respectively in the

walls

132 and 133 adjacent the ends 122 of the leaves 103. The

walls

132 and 133 are also provided with an offset

segment

135 and 136 adjacent to end 111. The leaf holder 101 has a width such as to snugly and frictionally fit within the inner surfaces ofthe

sidewalls

132 and 133.

The leaf holder 100 has a length which is equal to the length of the leaf holder 101 and a width sufficient to permit it to slide longitudinally between the inner surfaces of

walls

132 and 133 with substantially no lateral movement. One surface 140 of the leaf holder 100 is formed with parallel

transverse grooves

141 and 142. These grooves are equivalent in width and depth dimension to the grooves 107 and are adapted when the two

leaf holders

100 and 101 are parallelly aligned to align with the grooves 107. The groove 142 is designed to receive 26 leaves 102 of the type described and illustrated in FIGS. 11

18 and is formed with a plurality of dividers 143 similar in size and dimension to the dividers 110 to form a plurality of channels 144. The leaf holder 100 is adapted to fit between the walls 133and 134 with its upper surface 145, as viewed in FIG. 10, preferably coplanar with or slightly below a plane passing through the upper edges of thesidewalls'132 and 133 as viewed in FIG. 10. In this position the 26 leaves 102 are interleafed as hereafter described, with the 25 leaves 103.

A top cover 150 of metal or other conductive materials is designed to snap over the lower cover 130 to securely electrically

interengage leaves

102 and 103 and to provide a suitable electrical shield. The cover 150 is formed with an upper wall 151 and continuous depending sidewalls 152 and 153 that extend parallel to one another along the maximum dimension of the wall 151. The

sidewalls

152 and 153 are provided with inwardly biased

spring arms

154 and 155 integrally formed with 157 having a portion of reduced width terminating in a detent or integrally formed boss. The ends 156 and 157 are designed to project through the openings 134 respectively in sidewalls .133 and 132m engage the

outermost leaves

103 and 102 through the apertures 134. The degree of deflection of these

spring arms

154 and 155 determine the amount of pressure effected on the

leaves

102 and 103 to compress them towards one another thereby assuring a certain electrical connection between the interleaved leaves. Preferably the major portion of the

walls

152 and 153 should be spaced apart sufficient to permit the cover 150 to be slid over the cover from end 160 towards end 111. The offset portions and 136 of the cover 130 engage the slots 161 and 162 to limit movement of the cover when spring arms 154 and have engaged the

leaves

102 and 103 through the apertures or holes 134. When the springs'154 and 155 engage the holes 134 of the cover 130 the covers are interlocked against separation in a direction normal to the planes of the

walls

151 and 131.

Turning to FIG. 19 there is illustrated the arrangement of the interlocked leaves 102 and 103. In this arrangement it will be noted the enlarged areas 119 on the

leaves

102 and 103 at the adjacent interleaved ends are aligned one with the other. In the use of this connector the ends 164 of

leaves

102 and 121 of leaves 103 are suitably connected by a variety of means, some of which are hereafter described, to various circuitry. To interconnect the two halves of the connector the operator places the unmounted section or half of the connector (which we may assume is the half that includes leaf holder 100) on top of the chassis mounted portion which in this case would be the assembly that includes the leaf holder 101 and the cover 130. The leaves 102 are moved parallel to the leaves 103 to a position in which the tabs 1160f the leaves 102 engage the leaves 103 close to the dividers 110 where the dimensions of the various components 'are most constant. The leaf holder 100 is guided in longitudinal movement by the inner surfaces of the

walls

133 and 132 with the leaves 102 in registration with the dividers 1 10 and the leaves 103 in registration with the dividers 143. Thus as the leaf holder 100 'is drawn from the center of the holder 10] the leaves will remain in registration until the contact points of the

leaves

102 and 103 are in engagement. The

leaves

102 and 103 are thus pressed together until the longitudinal sides of the

leaves

102 and 103 are coplanar, as illustrated in FIG. 19. Following this the cover 150 is slid into position in a manner such as to permit the

spring arms

154 and 155 to move through the holes 134 to compress the leaves into positive electrical contact.

There are a number of advantages to the construction best illustrated in FIG. 10. For example, wires may be soldered, welded or otherwise attached to the leaves before assembly in the leaf holders. This permits a faster and automated assembly of contact leaves with less likelihood of defective units. Alternately tape cables can be made an integral part of one connector by rearranging the leaves to duplicate the arrangement in the drawings with the tape came leaf connected to its ultidesigned for the particular equipment with which it is to be used thereby providing a more efficient electrical circuitry than heretofore available.

The leaves may be assembled in a comb as illustrated to reduce handling of spaces and keep down costs of assembly.

In addition to these advantages there are a number of modifications which should be apparent. For example, instead of utilizing leaves such as illustrated at 102 and 103, every other leaf may be fully copper clad without etching the periphery as illustrated to provide shielding between every other circuit or between circuits as may be required. Further combinations of both individual and overall shielding are obviously possible. The fully copper clad leaves may, of course, be suitably terminated for proper electrical shielding characteristics.

Other variations of the leaf construction may be used. An I-I-shape or double leaf can be formed-to increase the density of the circuits with each line of contacts having individual springs. If two contacts are placed on the same board without separation precise alignment should be obtained to insure contact of each section. The solder end 121 of the leaves furthermore may be staggered in different directions so that some project further than others. This arrangement may facilitate attaching wires if the wires are attached after assembly. Alternately the ends 121 of leaves may extend at right angles to the major lengths of the leaves with these ends inserted through holes ina printed circuit board and electrically connected by flow soldering or electrodeposition to the contacts in the printed circuit board. Alternately the leaves may be inserted in saw slots between copper etchings on a printed circuit board and soldered to provide one-half of a connector. This arrangement is generally shown in a somewhat schematic arrangement in FIG. 20. In this arrangement a leaf 102 is inserted in each slot 170 of the printed circuit board 171 having a copper surface 172 with the etched contact portion of the leaf 102 suitably soldered along a line 173.

Referring to FIG. 21 there is shown a detail of an embodiment which may be incorporated with the structures of the previously described embodiments for use in multilayerprinted circuit arrangements. Multilayer-printed circuits have been commonly used for complex circuit arrangements. These printed circuits consist essentially of a plurality of dielectric layers 200 each of which may contain a printed circuit 201 on its upper surface 202. Slots 203 are formed in every other layer 200 with the slots 203 preferably aligned. Terminal contacts 204 of the intermediate layers 200 are exposed by these slots. The terminal contacts 204 are connected to the circuits 201 of the intermediate layers.

A male probe 205 of a connector having individual leaves 206 is shaped to interengage the printed circuit. In this arrangement the leaves 206 are dimensioned and spaced to fit snugly one in each slot 203. The lower surfaces of the leaves carry conductive terminals that are adapted to engage the terminal contacts 204 when the leaves 206 are interengaged with the slots 203. The conductive terminals on the lower surfaces of the leaves may be connected or integrally formed with conductors of external circuitry. Spring means which may, for example, comprise a spring-tensioned clamp or spring means of the type previously described is provided to exert forces in the direction of arrows A after interengagement in order to afford positive electrical engagement. In this arrangement the sides of the terminal contacts 204 are free so that forces in the direction of arrow A may deflect these contacts 204 for improved clamping.

A further modification of the construction contemplates means for preventing the metal from lifting from the dielectric base. In this arrangement the 'n ds of the leaves are sprayed with a suitable plastic coating such for example as Teflon, to which the metal will adhere better. In another arrangement the Teflon may be sonically welded to the dielectric base to effect a better bond to the base.

Leaves may also be formed by applying portions of copper wires to the dielectric base. The copper wire is flattened at its ends and if desired along its length to form an enlarged area at which a suitable connection may be effected. In this manner va suitableconnection to a circuit can be effected without any soldering or welding. The flattened portions may be attached to the dielectric base by any suitable means including, for example, bonding or sonic welding. In this connection each of two wires may be coated with a Teflon coating extending on one side only of the flattened portions and the two Teflon tions may then be joined.

There are wide varieties of modifications of the spring fea- Q tures possible depending upon the particular application desired. Where a few leaves are used fixed springs as illustrated may be used. However, where a larger number of leaves are required depending upon the thickness of the leaves provisions must be made to permit assembly without pressure, with the pressure applied after the assembly of the two components. The spring means may be integrally formed with the dust cover as illustrated in the drawings. Alternately the spring means may be formed separately. Where the unit is designed with relatively thick leaves and spaces the leaves themselves may be formed to provide the necessary spring action. In such cases the leaves will ordinarily be formed with conductive members on one side only.

With a very large number of leaves, the accumulated errors derived from variations in individual leaves and the width of the spaces intermediate them must be carefully controlled in order to assure efficient electrical operation. In this connection better spring pressures may be effected with large numbers of leaves by arranging the leaves in separate groups and applying separate spring means to each of the groups.

The spring means may be used to prevent accidental or even intentional disconnection of the terminals. In such an arrangement the spring means may be formed as an integral part of the base to which the connector is mounted. A suitable key would be provided to release the spring before engagement of the leaves and to lock the leaves after interengagement.

The spring means may be used for purposes other than to interengage the leaves. For example the leaves may be used to generate an electrical indicator when the halves of the connector are suitably interengaged thereby indicating that all the plugs are in and locked. In such an arrangement the springs are connected in series with the outside leaves of the individual contacts. These outside leaves may be left exposed for connection to a suitable outside signal circuit.

Where there is a critical application a double arrangement may be used. In such an arrangement the contact of one leaf is designed circuitwise for connection to either of two adjacent contacts on leaves of the other terminal member. If necessary a double set of spring means are employed. Such an arrangement increases the chances of avoiding an inadvertent misalignment.

With the precision normally available to connector manufacturers the embodiments described may be commercially made in sizes of connectors having spacings between leaves of in the order of 0.006 inches. If spacings of substantially less than 0.006 inches are desired without resorting to unusually careful manufacturing tolerances riffling or guide plates or other ancillary registration means may be used. While the preferred embodiments illustrate an arrangement in which the parts are connected by longitudinal movement relative to each other, other arrangements are contemplated in which the parts are moved angular to one another.

Referring now to FIGS. 22 to 24 inclusive there is illustrated a further modifications of the invention in which a pair of substantially identical mating pairs are provided with one of these two mating pairs illustrated in FIGS. 22 to 24 inclusive. The

por-

terminal is provided with a base 250 of suitable dimensions consistent with those previously described. Integrally formed and projecting from the surface 251 are a plurality of leaf members 252 which are each comprised of an elongated leaf 253 that extends lengthwise of the surface 251 and is interconnected to it at one end only by a leaf support or web 254 integrally formed with the leaf 253 and base 250. These leaf members 252 are preferably uniform in thickness and are spaced close together in parallel array. Each leaf 253 is relatively flexible near end 254A and stable dimensionwise and spacewise near end 255. Each leaf carries on one, or, if desired on both major surfaces a conductive lead 256 which may, if desired, be provided with enlarged and projecting

terminals

258 and 259 at opposite ends which function in the same fashion as those previously described in connection with the other embodiments illustrated. Suitable wire leads or other terminal connections may be made from the end 259 to a terminal board, integrated circuit or the like. Exemplary of such connections to a printed circuit board is the connection of FIG. 30. In this arrangement each leaf 253 is flow soldered directly to suitable leads 253A formed on the printed circuit board 2533 by first positioning the leaves between parallel flanges 254C formed in the printed circuit board. This rigid interengagement leaves the other end free for flexing.

In using these terminals a pair of like terminals are interengaged by aligning the webs 254 of one terminal with each space between webs 254 of the other. The two units are then slid into meshing relation in the direction of arrow A until the terminals 258 are interengaged. Suitable clamping or spring means of the type previously described as, for example, in connection with FIG. 10, may be used to compress the leaves together. There are several advantages in this structure. For example, it provides a single piece structure of dielectric material. In addition, the interengaging terminals can slide relative to one another their entire length without providing locating pins or devices of the type described in connection with other embodiments.

Referring now to FIGS. 25 and 26 there is illustrated a 275A this invention in which one terminal 270 is formed with a base 271 having a plurality of parallel spaced elongated dividers 272 extending upwardly from one surface 273 of the base 271. The dividers are arranged to receive and secure an elongated resilient wire 274 between each adjacent pair of dividers. These wires 274 are frictionally engaged at one end between adjacent dividers and may be further secured by a dielectric cap 272A secured to the dividers. The ends 275 and 275A projecting from one side of the dividers are designed for suitable attachment to leads or other circuitry as, for example, in FIGS. 31 and 32. These wires may also be formed integrally with the ends of circuit wires before being inserted between the dividers 272. In the embodiment of FIGS. 25 and 26 280A 281A the wires are alternately bent in different directions with wire ends 275A perpendicular to every other wire end 275. The resilient wires 274 are relatively rigid and stable adjacent the ends of the dividers in the area 276 but are easily deflected toward and away from one another at the ends 277 which may be reversely bent as illustrated. A second terminal 278 is also provided with a plurality of dividers 279 which are spaced apart a distance substantially equal to the diameter of the wires 274. One or both the surfaces of these dividers 279 may be provided with suitably formed conductive surfaces 280 including means at one end 281 for attachment by suitable means to an integrated circuit or the like. Such means may for example comprise either of the arrangements of FIGS. 33 and 34. As illustrated in FIG. 33 the conductive depositions or coatings on facing surfaces of adjacent dividers are integrally formed with elongated depositions 280A that extend parallel to one another over surface 281A from whence they may be connected to a printed circuit board. In FIG. 34 the slots between dividers are formed with a ridge 279A which effectively dielectrically isolates opposed coatings 280C and 280D.

The dividers 279 extend downwardly from the base of the terminal 278 a distance sufficient to permit interengagement so that the folded over portions of the wires 274 are engaged a by the dividers 279.

The dividers 279 have some degree of flexibility because of the undercuts 27915 or 279A and accordingly after insertion of the wires 274 between the dividers 279 a compressive force applying pressure in a direction normal to the length of the wires 274 may be applied as herebefore described.

Now turning to FIGS. 28 and 29 there is schematically illustrated a modification in which positive pressure means is at least partially embodied in the flexible conductive leaves. In this arrangement one terminal is provided with conductive leaf springs 287 securely retained in the base 285. These leaf springs project at one end 288 beyond the base 285 where they are adapted to be connected by means previously described to conductive members of a suitable circuit such, for example, as an integrated circuit. The other end of each leaf spring, which is made of a suitable flexible resilient metal, projects substantially beyond the end 288A of the base 285 and is terminated in sections 289 that deflect from the major plane of the springs 287. These sections 289 may be arcuate or bowed as illustrated or may assume any other shape in which spring action as hereafter described may be attained. The other terminal 290 is formed with a plurality of depending dividers 291 that extend parallel to one another and have on one depending side or the other, or both, a conductive section or lead 293 that may be suitably formed by any acceptable technique. These leads 293 are designed to have one end interengaged with the conductive leads 287 and have the other end attached by suitable means such as those previously described to a circuit such, for example, as an integrated circuit. The dividers 291 are spaced apart a distance greater than the thickness of the leaf springs 287 but less than the distance 294 which is the maximum distance widthwise of the leaf spring 287 from one surface to the other extremity as measured by the most projecting portion of the projectingsegment 289. In this arrangement the leaf springs 287 are interengaged between the dividers 291 by a drawing action of the type previously described with the leaf springs 287 interengaged with the conductive leads 293 at the projecting boss portions 289. Since the distance between adjacent surfaces of adjacent dividers 291 is less than the width of the boss 289 there is a compression of this boss projecting portion 289 thus effecting a positive spring action individually on each leaf spring.

Referring now to FIG. 35 there is illustrated a pair of

interengageable terminals

400 and 401. Terminal 400 is integrally formed of dielectric material and provides a base 402 from which depend a plurality of flexible contact leaves 403. These leaves which are each parallel to one another have an elongated portion 404 that is connected to the base 402 by an integral web 405. Each carries conductive surfaces of the type previously described and they are each spaced apart from one another by a slot 406 that extends the length of the leaves 403 from the forward end 408 to the rear end 409. The base 402 is formed with a shoulder 410 that extends across the base 402 at one end, as illustrated. The terminal 401 is formed of a dielectric member having angularly arranged

legs

412 and 414. The free end of leg 412 terminates in a lip 416 which extends parallel to and spaced from the leg 414. The distance between adjacent surfaces of the leg 414 and lip 416 is sufficient to receive the end 408 of the terminal 400 so that the terminal 400 may be pivoted about the lip 416 by interengagement of that lip with shoulder 410. Projecting upwardly from the surface 418 of the leg 414 are a plurality of wire conductors 420. These conductors are made preferably of a self-supporting relatively rigid but resilient wire. The conductors 420 are bent at one end 422 with this end 422 extending through the leg 414 with these ends 422 suitably terminated in a manner as herein described in connection with other embodiments. The wires 420 are all parallel to one another and precisely spaced at the erid422 for interengagement in a manner as hereinbefore described by the leaves 403. A transverse pressure' or spring means should be provided. It may comprise the type illustrated in FIG. 10. v

' Referring to FIG. 36 there is illustrated an arrangement providing two terminals 500 and 501. Terminal 500 is formed with a base 505 having a plurality of depending dividers 502 extending from one end, These dividers project downwardly or from one surface of the terminal base 505 in parallel arrangement with respect to one another and are separated from each other by channels or spaces 503. Preferably the dividers 502 are tapered as illustrated and are covered on each or one major surface with a suitable conductive material that extends lengthwise of the terminal 500 toward the end 507 as previously described in connection with other embodiments. Such taper may incidentally be used if desired in the other embodiments described. The dividers 502 form a shoulder 508 with the base 505.

The terminal 501 as illustrated in FIG. 36, is formed with a dielectric support and a plurality of wire conductors. These wire conductors are formed of rigid resilient conductive members that are supported parallel to one another. The wire conductors are each substantially U-shaped in configuration with

legs

510 and 512 connected in a bight portion 514. The ends of the

legs

512 and 510 are staggered with the legs 510 significantly longer than the legs 512. These wires are rigidly supported in a dielectric'housing having a base 516 molded or otherwise suitably formed about the legs 510. Dividers 518 integrally formed and projecting upwardly from the base 516 engage the legs 512 near but spaced from their end 520. A housing 522 may be frictionally or otherwise suitably engaged and formed about the dielectric support of the wires with the ends 520 of the legs 512 projecting beyond this housing. The ends 528 of the legs 510 are designed to be soldered or otherwise connected to a suitable terminal. The ends 520 of the legs 512 are adapted to be interengagedwith the dividers 502 of the terminal 500 when the terminal 500 is pressed downwardly into interengagement with the projecting legs 512.

if desired the wire forming the conductors in terminal 501 may be formed 'with alternate projecting segments 530 in place of legs 510.

I Referring once again to FIG. 33 there is illustrated a means by which a plurality of electrical connections may be made without the need of interengaging by a combing technique as previously described. In this modification the male and female connectors are similar in construction. The dividers 279 as illustrated are secured to the base 281A by interconnecting portions 279A which are located at one end of the dividers 279. This arrangement permits like connectors to be interengaged by pulling the two together respectively from the ends of the dividers 279 adjacent portions 279A. In such case a transverse pressure means must be provided to assure suitable electrical contact. This may be done by spring means of thetype previously described in connection with other modificationsJAltemately it may be done by tapering the dividers from a narrower end 279C to a wider end 279D. This tapering will of course make the spacing between adjacent dividers 279 wider at end 279C than end 279D thus permitting a longitudinal wedging action.

Each of the embodiments described should be provided with a spring means or cam means for effecting a transverseresilient pressure once an electrical connection has been effected. Several means have been described but the invention contemplates a wide variety of other means.

What is claimed is:

1. An. electrical connector having a mating pair of interchangeable terminals, each terminal having a plurality of aligned parallel-spaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a conductive layer covering at least part be compressed in the direction of said force to efiect a positive electrical interengagement between said contact terminals through said contact elements,

wherein said contact-elements are compressible and said means'for exerting a force is adapted to compress said contact elements one against the adjacent ones when said tenninals are interengaged,

wherein said means for exerting a force comprises a cam surface,

wherein each of said terminals includes a dielectric body with a shaft supporting said cam surface for rotational movement at one end of the aligned parallel-spaced contact elements,

wherein said dielectric bodies each having mating walls with guide means for locating said contact elements of one terminal in a preselected relation to the contact elements of the other terminal,

wherein the body of one terminal is formed with a recess within which one end of each contact element of said terminal is contained,

wherein said guide means comprises a plurality of guide pins extending from one terminal and mating recessed formed in the other terminal,

having a cam lever extending from said cam surface, means forming a recess in the terminal other than the one in which said cam surface is located in alignment with and adapted to receive said cam lever when said-cam surface mediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a conductive layer covering at least part of said surface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction of said force to effect a positive electrical interengagement between said contact terminals through said contact elements,

wherein said contact elements have an elongated insulating member, in facing relation with a conductive lead means for interlocking said terminals with the contact elements of one terminal parallel to the contact elements of the other terminal and aligned with spaced therebetween,

and with the conductive leads of the contact elements of one terminal facing the conductive leads of the contact elements of the other terminal, wherein said contact elements each comprise an elongated lateral movement,

wherein each of said leaf holders are formed with means for 5 I locating leaves of the other of said leaf holder in electrical engagement with the leaves thereof,

wherein at least one of said terminals has grooves and said leaves are each formed with laterally projecting tabs adapted to engage grooves.

3. An electrical connector as set forth in claim 2 wherein said tabs project laterally from each of the longitudinal side edges of said leaves,

said grooves formed in said leaf holder extending transversely thereof with respect to the length of said leaves.

4. An electrical connector as set forth in claim 3 wherein each of said leaf holders is formed with at least two parallel grooves adapted to receive tabs of said leaves secured to each of said leaf holders.

5. An electrical connector liaving a mating pair of interengageable terminals, each terminal having a plurality of aligned paralleLspaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contactelement includes an insulating base having a surface and a conductive layer covering at least part of said surface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction of said force to effect a positive electrical interengagement between said contact terminals through said contact elements,

wherein said contact elements have an elongated insulating member in facing relation with a conductive lead, means for interlocking said terminals with the contact elements of one terminal parallel to the contact elements of the other terminal and aligned with said spaces therebetween, and with the conductive leads of the contact elements of one terminal facing the conductive leads of the contact elements of the other terminal,

wherein said contact elements each comprise an elongated leaf, said terminals each having a leaf holder adapted to secure a plurality of said leaves in parallel-spaced alignment with a corresponding end of each leaf supported for lateral movement,

wherein each of said leaf holders are formed with means for locating leaves of the other of said leaf holder in electrical engagement with the leaves thereof,

including a conductive cover enclosing said leaf holders and leaves, wherein said cover has a pair of interengageable portions with each portion adapted to at least partially enclose a different one of said leaf holders, and

wherein said means for exerting a force comprises spring means secured to said cover and exerting a force transverse to the length of said leaves.

6. An electrical connector as set forth in claim wherein said spring means are integrally formed with said cover comprising,

depending sidewalls on one of said cover portions,

inwardly bent portions extending from said sidewalls forming said spring means adapted to engage the outermost of said aligned leaves.

7. An electrical connector having a mating pair of interengageable terminals, each terminal having a plurality of aligned parallel-spaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a conductive layer covering at least part of said surface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction as said force to effect a positive electrical interengagement between said contact terminals through said contact elements,

wherein said contact elements have an elongated insulating member in facing relation with a conductive lead, means for interlocking said terminals with the contact elements of one terminal parallel to the contact elements of the other terminal and aligned with said spaces therebetween, and with the conductive leads of the contact elements of one terminal facing the conductive leads of the contact elements of the other terminal. wherein said contact elements each comprise an elongated leaf, said terminals each having a leaf holder adapted to secure a plurality of said leaves in parallel-spaced alignment with a corresponding end of each leaf supported for lateral movement, wherein each of said leaf holders are formed with means for locating leaves of the other of said leaf holders in electrical engagement with the leaves thereof, including a conductive cover enclosing said leaf holders and aligned parallel-spaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a conductive layer covering at least part of saidsurface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction of said force to effect a positive electrical interengagement between said contact terminals through said contact elements,

wherein said contact elements each comprise an elongated leaf fixed at one end and deflectable in directions normal to its length at its free end,

means for registering the leaves of one terminal with the spaces intermediate the leaves of the other terminal comprising projecting means extending laterally from the leaves and adapted to be positioned in said spaces when the leaves from which they extend are initially positioned outside of said spaces.

9. An electrical connector as set forth in claim 8 wherein said terminals are each formed of a leaf support having a groove adapted to receive said means for registering when the leaves from which said projecting means extend are aligned in said spaces.

lOl056 0361

Claims

1. An electrical connector having a mating pair of interchangeable terminals, each terminal having a plurality of aligned parallel-spaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a conductive layer covering at least part of said surface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction of said force to effect a positive electrical interengagement between said contact terminals through said contact elements, wherein said contact eLements are compressible and said means for exerting a force is adapted to compress said contact elements one against the adjacent ones when said terminals are interengaged, wherein said means for exerting a force comprises a cam surface, wherein each of said terminals includes a dielectric body with a shaft supporting said cam surface for rotational movement at one end of the aligned parallel-spaced contact elements, wherein said dielectric bodies each having mating walls with guide means for locating said contact elements of one terminal in a preselected relation to the contact elements of the other terminal, wherein the body of one terminal is formed with a recess within which one end of each contact element of said terminal is contained, wherein said guide means comprises a plurality of guide pins extending from one terminal and mating recessed formed in the other terminal, having a cam lever extending from said cam surface, means forming a recess in the terminal other than the one in which said cam surface is located in alignment with and adapted to receive said cam lever when said cam surface is exerting said force.

2. An electrical connector having a mating pair of interengageable terminals, each terminal having a plurality of aligned parallel-spaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a conductive layer covering at least part of said surface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction of said force to effect a positive electrical interengagement between said contact terminals through said contact elements, wherein said contact elements have an elongated insulating member, in facing relation with a conductive lead means for interlocking said terminals with the contact elements of one terminal parallel to the contact elements of the other terminal and aligned with spaced therebetween, and with the conductive leads of the contact elements of one terminal facing the conductive leads of the contact elements of the other terminal, wherein said contact elements each comprise an elongated leaf, said terminals each having a leaf holder adapted to secure a plurality of said leaves in parallel-spaced alignment with a corresponding end of each leaf supported for lateral movement, wherein each of said leaf holders are formed with means for locating leaves of the other of said leaf holder in electrical engagement with the leaves thereof, wherein at least one of said terminals has grooves and said leaves are each formed with laterally projecting tabs adapted to engage grooves.

3. An electrical connector as set forth in claim 2 wherein said tabs project laterally from each of the longitudinal side edges of said leaves, said grooves formed in said leaf holder extending transversely thereof with respect to the length of said leaves.

5. An electrical connector having a mating pair of interengageable terminals, each terminal having a plurality of aligned parallel-spaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a conductive layer covering at least part of said surface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction of said forcE to effect a positive electrical interengagement between said contact terminals through said contact elements, wherein said contact elements have an elongated insulating member in facing relation with a conductive lead, means for interlocking said terminals with the contact elements of one terminal parallel to the contact elements of the other terminal and aligned with said spaces therebetween, and with the conductive leads of the contact elements of one terminal facing the conductive leads of the contact elements of the other terminal, wherein said contact elements each comprise an elongated leaf, said terminals each having a leaf holder adapted to secure a plurality of said leaves in parallel-spaced alignment with a corresponding end of each leaf supported for lateral movement, wherein each of said leaf holders are formed with means for locating leaves of the other of said leaf holder in electrical engagement with the leaves thereof, including a conductive cover enclosing said leaf holders and leaves, wherein said cover has a pair of interengageable portions with each portion adapted to at least partially enclose a different one of said leaf holders, and wherein said means for exerting a force comprises spring means secured to said cover and exerting a force transverse to the length of said leaves.

6. An electrical connector as set forth in claim 5 wherein said spring means are integrally formed with said cover comprising, depending sidewalls on one of said cover portions, inwardly bent portions extending from said sidewalls forming said spring means adapted to engage the outermost of said aligned leaves.

7. An electrical connector having a mating pair of interengageable terminals, each terminal having a plurality of aligned parallel-spaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a conductive layer covering at least part of said surface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction of said force to effect a positive electrical interengagement between said contact terminals through said contact elements, wherein said contact elements have an elongated insulating member in facing relation with a conductive lead, means for interlocking said terminals with the contact elements of one terminal parallel to the contact elements of the other terminal and aligned with said spaces therebetween, and with the conductive leads of the contact elements of one terminal facing the conductive leads of the contact elements of the other terminal. wherein said contact elements each comprise an elongated leaf, said terminals each having a leaf holder adapted to secure a plurality of said leaves in parallel-spaced alignment with a corresponding end of each leaf supported for lateral movement, wherein each of said leaf holders are formed with means for locating leaves of the other of said leaf holders in electrical engagement with the leaves thereof, including a conductive cover enclosing said leaf holders and leaves, wherein each of said leaf holders is integrally formed with a plurality of dividers forming a series of channels adapted each to receive one of said leaves with said dividers interposed between adjacent leaves and extending longitudinally less than the length of said adjacent leaves.

8. An electrical connector having a mating pair of interengageable terminals, each terminal having a plurality of aligned parallel-spaced contact elements with the spaces intermediate adjacent contact elements having a width to receive a contact element of the other terminal in interengagement wherein each said contact element includes an insulating base having a surface and a cOnductive layer covering at least part of said surface and bonded to said base, and means for exerting a force normal to said contact elements when said contact elements are interengaged whereby said contact elements may be compressed in the direction of said force to effect a positive electrical interengagement between said contact terminals through said contact elements, wherein said contact elements each comprise an elongated leaf fixed at one end and deflectable in directions normal to its length at its free end, means for registering the leaves of one terminal with the spaces intermediate the leaves of the other terminal comprising projecting means extending laterally from the leaves and adapted to be positioned in said spaces when the leaves from which they extend are initially positioned outside of said spaces.