US3251125A

US3251125A - Tool for tab terminal connector means

Info

Publication number: US3251125A
Application number: US423620A
Authority: US
Inventors: Robert J Kinkaid; Robert H Frantz
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1963-08-05
Filing date: 1964-12-02
Publication date: 1966-05-17
Anticipated expiration: 1983-05-17
Also published as: FR1402691A; DE1465098B2; US3173737A; NL6408604A; JPS44991B1; DE1465098A1; CH422099A; BE651359A; DE1465098C3; GB1007811A

Description

May 17, 1966 Original Filed Aug. 5, 1963 R. J. KINKAID ETAL TOOL FOR TAB TERMINAL CONNECTOR MEANS 5 Sheets-Sheet 1 a8 QOBERTI (/Nm/a efa/ QPBERT ,7,

y 1966 R. J. KINKAID ETAL 3,251,125

TOOL FOR TAB TERMINAL CONNECTOR MEANS Original Filed Aug. 5, 1963 5 Sheets-Sheet 2 INVENTOE= QZL'J/Kw #444.

May 17, 1966 R. J. KINKAID ETAL TOOL FOR TAB TERMINAL CONNECTOR MEANS 5 Sheets-Sheet 3 Original Filed Aug. 5, 1965 y 1966 R. J. KINKAID ETAL 3,251,125

TOOL FOR TAB TERMINAL CONNECTOR MEANS Original Filed Aug. 5, 1963 5 Sheets-Sheet 4 [1W5 N T02 P012527 7 (mm/0 H/ B RT H. 5411172.

May 17, 1966 R. J. KINKAID ETAL 3,251,125

TOOL FOR TAB TERMINAL CONNECTOR MEANS Original Filed Aug. 5, 1963 5 Sheets-Sheet 5 I N VE IV TOE: 2 OBERT f/Nm/o f a/ R se/er H. Pn/wrz United States Patent TOOL FOR TAB TERMINAL CONNECTOR MEANS Robert J. Kinkaid, New Cumberland, and Robert H. Frantz, Mount Holly Springs, Pa., assignors to AMP Incorporated, Harrisburg, Pa.

Original application Aug. 5, 1963, Ser. No. 299,866, now Patent No. 3,173,737, dated Mar. 16, 1965. Divided and this application Dec. 2, 1964, Ser. No. 423,620

1 Claim. (Cl. 29203) This application is a division of a parent application S.N. 299,866 filed August 5, 1963, for Printed Circuit Edge Connector, in the name of R. J. Kinkaid et al., granted as US. Patent No. 3,173,737 on March 16, 1965.

This invention relates generally to an improved printed circuit edge connector assembly of the type utilized to interconnect components mounted on a printed circuit card and to connect such components to individual or paired conductive paths interconnected with the assembly by removable tab terminals. The invention features a novel latching assembly having a utility apart from printed circuit card use and includes a preferred embodiment of such in a novel terminal commoning block. The widespread acceptance and use of printed circuit cards has sponsored the development of the so-called edge type con- ,nector wherein a plurality of contact spring members are secured within a common insulating block member to define contact faces adapted to receive and interconnect each path of a number of parallel conductive paths mounted on the surface of an insulating card or panel.

v Extensions from each spring member are usually positioned in the common block to provide connection points for associated circuit paths terminated thereto in some fashion. A typical construction of the prior art is shown in US. Patent No. 2,908,775 to L. Gilbert granted October 13, 1959. Further examples of the prior art devices are shown in US. Patents No. 2,935,725 to B. Fox granted May 3, 1960, No. 2,870,424 to E. E. Franz granted January 20, 1959, No. 3,001,171 to F. A Shultz granted September 19, 1961, and No. 3,016,508 to G. J. Lalonde granted January 9, 1962.

While the connectors of the prior art have generally answered the limited needs for which they were designed, field experience has outlined new demands not met by prior art devices and has provided an assessment of major shortcomings understandably overlooked in the early efforts of development of edge type connectors.

A basic shortcoming has been the lack of structure to adequately provide removable associated leads in conjunction with means for latching such leads against accidental withdrawal. The typical approach has been to provide either a soldering tab which is, of course, not readily removable or a bare conductor or taper pinreceptacle not suitable for repeated insertion and withdrawal. A shortcoming in common with the above approaches has been the lack of an insulating structure completely overlying the conductive portions of the connector. This lack practically bars use of such connectors in any environment crowded by other electrical components and leads; the typical environment found in aircraft, ships and the like.

A further shortcoming has been the lack of a printed circuit card spring member which is readily producible and useable and which at the same time ofiers a sufficient contact area driven by sufficient contact spring pressure. In one prior art approach, for example, the contact surface for the printed circuit card is defined by raised indentations in the contact spring member which reduces the total contact surface to that of a single point or at most a few points located along the indentation width. Through this approach contact pressures are of course maximized but unfortunately contact surface Wear is so increased as to almost insure removal of precious metal plating from contact surfaces as well as damage to corresponding con- 3,251,125 Patented May 17, 1966 ductive paths on printed circuit cards. Other prior art etforts have extended the possible contact surface between card path and contact spring by the use of cantilevered arm members angled to coincide with the plane of the printed circuit conductive path. Yet other approaches have made use of bellows type spring members having a length sufiicient to provide a relatively long trailing portion to define the contact area. Experience with such spring configurations has shown a tendency for the springs to become set following only a few insertions of a printed circuit card and in a manner to so reduce spring force as to reduce the qualities of electrical connection below that which is adequate. Additionally, with spring members of considerable length problems have been encountered in maintaining production tolerances to achieve proper positioning of contact surfaces which are well removed through a number of turns from the juncture of spring arm and supporting member. This adversely affects use and reliability. A still further shortcoming of certain prior art edge connectors has been the lack of any facility for changing the contact springs or the associated terminals to thus change the interconnections between card components-or replace worn or damaged contact members. In the prior art edge connectors having a facility for replacing contact springs or the associated terminals, a shortcoming has been found with respect to the complexity of insulating and metal parts required to mount and lock the members within the insulating housing block. This has resulted in a complexity of insertion-withdrawal tooling as well as in extending the time required for such and the likelihood of contact damage due to the excessive manipulation required. Still further shortcomings include the required use of polarized-terminals for associated leads, the possibility of terminal movement within the connector assembly, the provision of contaminant entry points and over-all lack of adaptability to economical production and use.

Accordingly, it is an object of the invention to provide a tool for a multiple connector incorporating contact spring members mounted Within a protective insulating housing.

It is another object of invention to provide a tool for use with an improved multiple connector featuring ter minals, terminal spring members, an associated latch structure which permits to rapid insertion and withdrawal of the terminal members without part damage.

It is yet another object of invention to provide a tool for use with an improved multiple connector wherein the configuration of contact assembly tool and insulating housing block is such as to reduce tolerance problems with respect to initial assembly and use and thereby enhance cost or reliability.

The foregoing objects are achieved by the invention through the combination of an insulating housing block including a series of essentially straight walled transverse cavities having a single projection to cooperate with and retain a series of multiple function contact spring members. The contact spring members are orientated to receive on one side through a slot the conductive paths of a printed circuit card and on the other side one or more tab terminals connected to associated circuit leads. The

spring contact members fitted within the block are of a 1 unique configuration to both permit the use of a simple one-piece molding and yet provide a means whereby the members are locked therein against accidental withdrawal and relative movement. As an important aspect of the invention the contact members include a unique spring arm configuration for each of four separate functions of contact and mechanical connection. Each contact spring features an embossed stiffening spine and angular disposition to minimize tolerance and set problems and maximize contact area and pressure. The latching spring features a progressive stilfening action and an overtravel blocking feature which combine to provide a reliable but simple captivation of tab terminals and preclude terminal or contact member damage by simplifying tool requirements.

Utilizing the above advantages of contact member construction an alternative embodiment is included for extending the utility of the invention to accommodate a greater number of associated conductive lead terminals. Yet a further embodiment is included utilizing certain of the principles of the block and spring construction of the invention to accomplish a commoning function for large numbers of associated conductive leads apart from printed circuit card use. Finally, a tool embodiment of simple construction is included which permits rapid terminal withdrawal without contact damage. In the drawings:

FIGURE 1 is a sectioned perspective of one embodiment of the connector of the invention showing the general configuration of the insulating housing and contact member mounting features;

FIGURE 2 is an elevational section of the connector embodiment of FIGURE 1 depicting a contact member,

its engagement within the housing block and its operation in receiving a printed circuit card;

FIGURE 3 is a section taken along lines 3-3 of the embodiment shown in FIGURE 2 further showing the cooperation of the contact member and housing cavity;

FIGURE 4 is a perspective showing the contact member of the embodiment shown in FIGURE -2 removed from the housing to depict its latching feature with a preferred construction of tab terminals;

FIGURE 5 is a section taken through the width of the contact along lines 55 of FIGURE 4, showing the tab terminal spring members;

FIGURES 6 and 7 are sectional views taken along the .length of the contact member, lines 66 and 77, revspectively of FIGURE 5;

FIGURE 8 is a section taken along the length of the contact member, line 8-8 of FIGURE 9, showing a tab terminal inserted within the terminal spring member of the contact member;

FIGURE 9 is an elevational view of the contact member apart from the block including a fully inserted tab terminal and a partially inserted tab terminal to show the operation of the novel latching feature of the invention;

FIGURE 10 is an alternative embodiment of the connector of the invention showing a modified housing con- .struction in section in conjunction with a modified contact spring member;

FIGURE 11 is an elevational section taken along lines 1111 of the connector shown in FIGURE 10;

FIGURE 12 is an elevational section taken along lines 1212 of FIGURE 10;

FIGURE 13 is an end-on view taken from lines 13--13 of the assembly of FIGURE 10;

FIGURE 14 is a perspective of yet a further embodiment of a contact spring of the connector of the invention adapted for use as a commoning means for numbers of tab terminals and associated conductive leads;

FIGURE 15 is a sectional view of the block embodiment adapted for use with the commoning contact spring shown in FIGURE 14;

1616 of FIGURE 15;

FIGURE 17 is a perspective of an extraction tool embodiment for use with a connector of the invention; and

FIGURE 18 is an elevation showing part of the connector assembly in conjunction with the tool shown in FIGURE 17 in use.

Turning now to a detailed description of the invention, FIGURE 1 shows a fragmentary length of one embodiment of the connector block member of the invention. This member labeled 10 is preferably a one-piece molding of dielectric insulating material of the thermo-setting type, such, as diallyl phthalate, epoxy, phenolic resin or the like. In an actual unit, a glass loaded diallyl phthalate resin was utilized. In practice, block members 10 are made up to accommodate standardized printed circuit card sizes and numbers of conductive paths such as for example, cards having elevent pairs of conductive paths located on the surfaces of the card. It is the usual practice to provide at the ends of block member 10, not shown, mounting flanges apertured to receive members for fastening the block through a suitable opening in a connector panel.

As can be visualized from FIGURE 1, the greater length of block member 10 is along a diagonal axis extending to the right of the figure. Along a side 12, of 10, is a centrally located slot 14 sized to accommodate the insertion of printed circuit cards therein. Bordering slot 14 are beveled

portions

15 and 16 which serve the dual purpose of easing insertion of printed circuit cards and eliminating the most frequent point of block breakage.

The opposite edge of block 10 includes a series of rectangular-apertures 18, individually defining entry to a series of cavities 20 which extend across the width of the block to join slot 14. As can be seen from FIGURE 1, each cavity 20 has a relatively simple interior configuration to thus permit block 10 to be molded in one piece. The relative simplicity of the construction of block 10 compares favorably to the constructions of prior art devices which include numbers of interiorly formed slots, projections and grooves and in certin instances anchoring apertures in the top and botton walls of the block members. The block member 10, as shown, includes only apertures at the points of entry of conductive paths. The provision of a block having no apertures in the top or bottom walls improves overall connector operation by reducing access for dust, moisture and the like which may contaminate contact surfaces within the connector assembly.

Viewing FIGURE 1 further and additionally FIGURES 2 and 3, cavity 20 is seen to have bottom and

top walls

22 and 24 and a side wall 26 which are straight and free of offsets, projections and the like. The end wall 28 partially closing one end of cavity 20 is also of a relatively simple configuration. The side wall 30 which is the other side of the wall 26 of an adjacent cavity has essentially a planar surface configuration with a single raised projection 32 extending along a portion of its length with one end near aperture 18. Projection 32 includes a slightly rounded end portion 34 and an opposite abrupt face 36 which serve to lock a spring contact member within cavity 20 ina manner to be hereinafter described. 2

Wall 30 further includes at the other end a slot 38 aligned with slot 14. The

portions

42 and 44 of wall 30 defining slot 38 are spaced apart by the width of slot 14 to accommodate insertion of a printed circuit board as shown in FIGURE 2.

Vertical face 40 of slot 38 is positioned with respect to slot length to serve as a stop to control the depth of insertion of printed circuit boards Within the connector. The

portions

42 and 44, respectively formed in wall 30 serve to provide printed circuit card support and electrical and mechanical isolation between spring arms of individual spring contacts within each cavity 24. Located between the walls 26 and 30 are V grooves such as 48 shown extending out into bevel 15 in the lower part of wall 12.. A similar V groove 46 is positioned in the upper walls 12 for each cavity 20. The purpose of grooves 46 and 48 is to provide key-ways to cooperate with keying projections of the printed circuit board;

It will, of course, be appreciated that each of the cavities 20 are as described and others would be provided adjacent thereto. As will be made more apparent hereinafter, the relatively straight and uncomplicated surfaces defining each cavity 20 serve to simplify mounting and retaining contact spring members inserted within each cavity. The use of a single projection, such as 32, extending within each cavity 20 as will be hereinafter shown, ad-

ditionally, simplifies the insertion procedures necessary during assembly of the contact spring members within the connector block and withdrawal procedures during the replacement of worn or broken parts as well as prow'ding an important simplification of the tooling requiredfor such procedures. All of these factors tend to make both production and use of the novel connector of the invention more economical and added to the over-all reliability of the connector by reducing the opportunity for failure.

The contact spring assembly which represents the embodiment of the invention utilized with the connector block above described is shown as member 50 in FIG- URES 2-9., Member 50 is, of course, of conductive metal and preferably of material having spring quality characteristics. In an actual embodiment, member 50 was formed of a single piece of contact grade Phosphor bronze blanked, stamped and formed into the configuration shown and thereafter over-plated with a layer of nickel beneath a layer of gold.

Basically, the contact spring member 50 has four separate but related functions including, features to secure the member within cavity 20; spring arms of one configuration to connect with a printed circuit card; spring arms of another configuration adapted to connect with terminals inserted therein and, further spring arms adapted to mechanically latch tab terminals within member 50.

As a first of these features, member 50 includes as shown in FIGURE 5 a centrally disposed wall 5-2 joined by intersecting walls 54 to define a channel 56 considerably wider and slightly deeper than similar dimensions of projection 32 extending within cavity 20. Extending within channel 56 is a c-antilivered spring member 58 struck inwardly from wall 52 to define a face 60 adapted to cooperate with face 36 of projection 32 and relative to FIGURES 2 and 3, limit the leftward axial movement of 50 within block 10. The width of face 60 is preferably made sufficiently large as to define a bearing area with face 36 so as to avoid tolerance problems and provide a suflicient area of contact to prevent excessive axial loading of 50 from causing 60 to bite into or break off portions of 32. The inward disposition of 58 is preferably suflicient to place 60 well down on face 36 for the same reason. The length of 58 relative to the thickness of the material is preferably made such as to define a stiff spring action since the principal function of 58 is to lock contact 50 within block rather than to latch such member in a manner adapted for frequent use of spring characteristics. This may be better appreciated by considering that as a matter of practice member 50 would rarely be inserted, removed and reinserted since removal would only be for the purposes of replacing a worn or broken part.

As an extension of wall 52, a tapered portion 62 is provided extending longitudinally along the wall center line away from 58 and formed outwardly as shown in FIGURE 3 with respect to channel 56 at an end 64 to a maximum excursion at a point 66. From point 66 extension 62 curves back inwardly through the plane of 52 to define a flange 68 having an interior face 70 adapted to cooperate with a face on the end of34 of projection 32. As will be apparent from FIGURE 3, the distance between face 70 and face of spring 58 is substantially that of the length of projection 32 to resist axial movement and thus hold member 50 within block 10 against the forces of insertion and withdrawal of the printed hold 50 within cavity 20 between the faces of wall 26 and projection 32. As will be apparent from FIGURES 'with side walls 26 and 30. Thus, from the channel 56 formed by walls 54, the material of 50 extends outwardly parallel to 52 to form a wall 74, thence upwardly parallel to walls 54 to form a wall 76 and inwardly again parallel to wall 52 to form a wall 78.

Walls

74, 76 and 78 and

similar walls

73, 77 and 79

form receptacles

80 and 81 on either side of channel 56. In each

wall

74 and 73, there is an embossment struck inwardly such as 75, shown in FIGURES 5 and 6, with respect to receptacle 80. Emboss-ment extends along a substantial portion of receptacle and along a substantial width of of wall 74 and serves to strengthen the receptacle and member 60. :Its most important function is however, to define a contact surface area for the engagement of a tab terminal inserted therein. 'Frorn FIGURE 5 it should be apparent that the

walls

73, 74, 76, 77, 78 and 79 define an external cross-sectional configuration of member 50 adapted to place considerable surface area against the walls of cavity 20 to secure 50 against relative transverse movement.

With the general features of member 50, with respect to maintenance within cavity 20 now in mind, the improved printed circuit contact spring of the invention will now be described. Referring to FIGURES 2, 3 and 4, a description of the upper contact spring arm will be given with the understanding that the lower spring arm is identical in structure and function. As can be seen from FIGURE 2, the arrangement of the printed

circuit spring arms

84 and 104, is such as to define contact surfaces extending down within the path of travel of a printed circuit board 110 and the conductive paths 112 and 114 on the top and bottom surfaces thereof. The relaxed position of the spring arms as shown in FIG- URES 4 and 9, is such that upon insertion of board 110, the conductive path 112 will engage and press against the upper spring member 84 and the lower path 114 will similarly work against the lower spring member 104 and provide'interconnection to components electrically connected to such conductive paths. V

As will be further apparent from FIGURE 2, spring arm 84 is an integral extension from wall 76; the wall being extended outwardly to define an overhang 86, a first arm position 88, a bend 92 and a further arm portion 93 defining the contact surface areas. Arm 93 includes a section 94 joining a relief or pocket 96, a section 98 and a turned up portion 100. The contact surface areas for arm 84 are defined by the underside surfaces of

sections

94 and 98.

At the juncture of arm 84 and extension 86 is a support portion 87 extending outwardly from wall 74, to join 84. Support portion 87 is included to generally ruggedize the spring members by strengthening the support of the arm at the point most likely to fail. Within the center area of extension 86 and extending out along the substantial length of armportion 88 is a tapered embossment 90, shown in FIGURES 4 and 6. Embossment 90 serves to substantially stiffen not only the point of juncture of arm portion 88 and extension 86, but also to strengthen 88 and provide improved spring characteristics. The tapered configuration of 90 along the surface of 88 toward 92 results in stiffening actionwhich is gradually reduced per unit of spring length. Thishas been found to provide a greater degree of bending of the outer portions of 88 which feature serves to maintain substantial contact pressure without permitting the spring member 84 to assume an unwanted set; particularly after use with oversized printed circuit cards.

As a most important advantage of the spring arms of the invention, each arm portion 88 includes a bow inwardly as shown in FIGURE 2. It has been found that the provision of even a slight inward bow greatly en- 7. hances the ability of the spring action to provide sufiicient and constant contact pressure and at the same time act to reduce the stress which tends to set and even break the spring arm at its point of support. The inclusion of a straight section or an outward bow of the configuration of the prior art has been found to concentrate the bend-.

ing moment and incident strains to the point of juncture of the arm, rather than at some point along the middle of the arm.

The bend 92, is maintained with a substantial interior radius as shown in FIGURE 2, to effectively transfer initial spring movement to a point toward the middle of arm portion 88. There is of course, a bending moment of arm 93 about bend 92, but the inclusion of a large radius bend has been found to effectively delay such until the board is substantially inserted. This operates as follows. Spring arm 93 carrying the contact surfaces has a relaxed configuration as shown in FIGURE 9, such that as board 110 is inserted, the end thereof strikes the section 94 first. This causes spring arm movement upwardly of the outer portions of 88, with little or no spring movement of 93 about bend 92.

Further insertion of board 110 engages section 98 of 93 effecting a slight further upward movement, of arm portion 88 and upward movement of 93 about 92, followed by a downward movement of 92 and 94 which action operates to bring both contact surfaces into firm contact with the printed circuit conductive path 112. The pocket 96between the contact surfaces serves to define a reservoir to entrap dust particles and other loose material wiped from the contact surfaces during engagement of board .110. The turned up end 180 assures that no sharp edge or burr left from the blanking or stamping operation will damage the printed circuit card conductive path during insertion, and particularly withdrawal of board 110.

By providing the inward bow in arm portion 88, the desired operation above described is assured. Additionally, by having a positive requirement of an inward how, the presence of an outward bow is absolutely precluded, which would not be the case of the spring specifications called for a straight section at a given tolerance which could permit a slight outward bow. The outward bow condition is considered as the worse case with respect to causing spring set and incident reduction of contact surface pressure. It has been found that the presence of an outward bow in portion 88 will almost assure that only the forward section 98 will be in contact with the printed circuit card path 112; the section 94 being raised as the spring arm portion 88 bends about its juncture with extension 86.

Referring now to FIGURES 4 and 5, generally, and FIGURES 6, 7 and 8, specifically, the structure and operation of the spring contact members adapted to accommodate tab terminals will be described. As can be seen from FIGURES 4 and 5, assembly 50 includes two

contact spring members

120 and 132, which are substantially identical in function and structure. As can also be seen from FIGURES 4 and 5, each spring arm is an extension of a wall portion adjacent wall 54, such as 78 with respect to member 120. The member 120 includes a cantilevered arm 122, having disposed along a substantial portion of its length, a tapered rib 124, with the taper extending toward the free end of the arm. The end of the arm is turned upwardly as at 126 to positively preclude damage to a tab terminal by burrs or sharp edges incident to stamping and blanking. Rib 124 is struck upwardly to strengthen the spring action of 122 at the point most likely to fail; namely the point of juncture of the arm with wall 78. Additionally, rib 124 operates to compound the spring moment of the spring arm by forcing the forward portion of the arm including the contact surface 130 to initially swing upwardly about the end of the taper prior to the arm moment about the juncture with wall 78 to force surface 130 against the surface of a terminal. As a further point, and as can be seen from FIGURE 8 the embossment 75 opposite arm 120 is of a height such as to define travel for a tab terminal such as 140 along the center line of the receptacle and of a length such that the insertion of 140 provides a spring operation wherein the rear portion of arm including the contact surface 128, is brought to bear against the surface area between spring and terminal. The provision of a bevelled entry portion, such as 132, in conjunction with an arrangement wherein the tab terminal has a travel along the center line of the receptacle operates to ease insertion procedures.

The tab terminals utilized with spring member 50 are identical with respect to each other and engagement within

receptacles

80 and 81. The preferred construction is shown in FIGURE 4, with respect to terminal 140 to include a blade 142 of rectangular cross-section, having a blade tip 144 bevelled inwardly from all four walls. At the opposite end are

projections forming stops

146 and 147 extending outwardly beyond the width of the blade to define a width dimension from outer edge to outer edge approximating that of the receptacle 80 as measured from the outside of the

walls

76 and 54. The fonward and rear outer edges of stops 146 are abrupt surfaces perpendicular to the longitudinal axis of blade 142. The rear edges of each stop lead into a necked down extension of the terminal, which is embossed as at 148 to provide strength at the point of juncture between. the blade and an integral lead connecting portion including ears 150 adapted to be crimped inwardly against the conductive strands of a stripped cable 154. The extension includes a cable support barrel 152. The terminal 140 is formed of a flat stock sheet material stamped and blanked into a configuration with the ears of 150 extended upwardly prior to crimping. In an actual unit the terminal was formed of brass, bronze or the like plated with nickel overplated with gold. After a suitable stripping of the end insulation of the conductor 154, and insertion through 152, cars 150 are formed inwardly as by crimping to terminate the conductor to the blade.

Turning now to the advantages of the immediately foregoing features and to a final feature of the member 50, FIGURE 9 shows the latching operation which serves to secure tab terminals against accidental withdrawal. Formed as an integral extension from 68 are two

arms

162 and 172, which are identical to accommodate

terminals

140 and 160. Describing only 162, there is included at the point of juncture with 68, a reverse band 164 which extends inwardly toward the center axis of member 50 and then outwardly to include a spring section 166 having a face 167 adapted to cooperate with the rear surface of stop 147 to lock 140 within receptacle 80. Proximate end face 167 there is included an outward projection 168, as better shown in FIGURE 4, which prevents arm 162 from being driven inwardly past the edge of tapered portion 62. This operates to preclude 162 from being disabled by excessive bending caused by insertion and withdrawal of a terminal or through the tool blade used for such. The reverse bend 164 defines a point of contact 170 with the upper surfaces of projection 32 such that the spring moment of 162 is made sufiiciently stiff to firmly latch 140 in position but yet permit repeated deflection for changing terminals. the inclusion of the reverse bend 164-t6 define a spring action from point 170 substantially reduces the likelihood of breakage of the spring arm at the point of juncture with 68. In operation, as the terminal is inserted within receptacle 80 the edge of the stop 147 strikes the outer surface of the spring member 162 and cams the spring inwardly to permit complete insertion. As the terminal homes within the receptacle and the faces thereof abutt the receptacle faces, the width of the stop permits the spring arm to snap outwardly against the back face of the stop to latch and snub the terminal against withdrawal.

An important feature of the terminal latching engagement of the invention is that the terminal members may It has been found that be inserted without regard to polarization. 'I he planar blade construction of the terminals in conjunction with stops on both sides of the blade permits latching by 162 or 172 with the terminal oriented in either of the positions shown in FIGURE 4. Providing a terminal and latch construction such that the terminals may be inserted without regard to polarization, greatly facilitates assembly and withdrawal procedures as well as simplifying tooling requirements. This will be more fully described with respect to FIGURES 17 and 18 hereinafter.

Turning now to an alternative embodiment of the invention, FIGURES 13 show a connector having a pair of tab terminals for each printed circuit card conductive path. The alternative embodiment shown as connector 180 in FIGURE 10, is comprised of an insulating housing 181 of dielectric material having a rear terminal housing portion 182 and integral therewith, a forward spring arm housing portion 184. The rear portion 182 includes a pair of

cavities

186 and 188, extending through the width of 182 to join a common cavity 190 within portion 184. The outer wall of 184 is provided with a slot 192 adapted to accommodate the insertion of a printed circuit board 196, having upper and

lower paths

198 and 200, respectively. Surrounding slot 192 is a bevelled portion such as lower part 1% similar in function to the bevels and 16, above described. Within cavity 190 are

wall portions

202 and 204 extending inwardly to define a bearing surface for printed circuit board 196 and to isolate and insulate the contact spring members from adjacent contact members.

Located within each cavity is a projection similar to the projection 32 described with respect to the embodiment of FIGURE 1. As can be seen from FIGURE 11 with respect to the pair of cavities, 186 and 188, the projections 206 and 288 respectively extend from relative opposite walls of the cavities. This permits the use of an identical spring contact member for each cavity. Dividing

cavities

186 and 188, is a common wall portion 210 extending along the length of 182 to-define opposite slot 192 a bearing surface 212 as shown in FIGURE 10 adapted to receive and block inward movement of the spring arms of the contact member-s. Through the provision of the end 212, the spring arms are positively pre- I vented from contacting each other to cause an electrical short between the circuit path in the upper part of the assembly and thepath in the lower part. A vertical face 214 is provided at the end of 210 to act as a stop against which the end of printed circuit board 196 will operate.

Provided in the outside portion of each cavity is an offset such as 216 to define a face 218 adapted to serve as a locking surface to prevent withdrawal of a contact member from the cavity. Further included adjacent offset 216 is an aperture 220, adapted to receive a tool blade utilized to withdraw a contact member from the cavity. Cavity 188, of course, includes portions similar to 216, 218 and 220, as shown in FIGURE 10. A face 222 is provided extending up from each cavity projection to act as a stop against which each contact spring member is held against axial movement developed by withdrawal of a printed circuit board. Further included within each cavity and as better shown in FIGURE 13, is a projection 224 extending along the cavity centerline to join a raised ledge 226 which cooperates with the opposite wall of a cavity to support the latching portion of the spring member within the cavity. As can be seen from FIGURE 10, the connector block, 181 is of a con struction which may be manufactured in a one-piece molding to assure integrity of the unit. Note also that there are no apertures on the top and bottom walls of the block section 182 to provide access for dust or other contact surface contaminants.

Within each cavity is an identical contact membersuch as 230 shown within cavity 186. The spring members include, referencing now FIGURES 10 and 11, a central wall 232 joined by side walls 234 to define a channel member 236 adapted to cooperate with center projection 206 to key insertion of the contact member and support such against transverse movement relative to the housing. From the ends of walls 234 extend

walls

238, 240 and 246, to define on one side, a terminal receptacle 250 and a similar structure on the other side to define a terminal receptacle 252. The wall spacing is such as to define bearing surfaces with the appropriate cavity walls. The upper wall 249 shown in FIGURE 10 includes an extension having a reversely struck out spring member 254 relative to the material thickness, which is such as to define a relatively stiff spring action to lock rather than latch assembly 230 within the cavity 186.

As an extension of wall 232, there is provided as shown in FIGURE 13 an alternative latching construction consisting of a wall 260, having at its end a formed U- shaped portion 262 with each wall of the U including a spring member extending back toward the printed circuit spring arm of the contact member. Each spring member 264 and 266 as shown in FIGURE 10 is formed inwardly such that the members are in light contact and then bow outwardly to define end faces such as 268, adapted to engage the stop of tab terminals inserted within the contact member 239. One such terminal mem her is shown engaged in the upper part of cavity 186. The latching embodiment shown in FIGURE 10 has the advantage of occupying less width than the embodiment shown and described relative to FIGURE 9. It has been found that the provision of the spring arms 264 and 266 contacting each other through an inwardly bowed portion operates with similar advantages to those of the embodiment above described; namely that a relatively stiff but workable spring action is defined with unwanted set or breakage at the point of juncture of the spring arm and its support 262 eliminated. The member 230 is adapted to receive tab terminals such as 270 in one or both of the

receptacles

250 and 252 to contact

terminal spring arms

272 and 274, respectively.

Arms

272 and 274 are identical in structure and function to arms and 132 described with respect to FIGURES 4-8.

The printed circuit spring arms, shown in FIGURE 10 as 230, are essentially the same as the spring arms defined with respect to FIGURE 2, except that only a single spring arm is provided for each contact member 230 and the arm is oriented outwardly rather than inwardly. Additionally, the arm end 282, is for-med as indicated to engage the forward portion 214 to prevent contact with the opposing spring arm of an adjacent member 230.

With the embodiment shown in FIGURES 10l3 and only a slightly more complicated housing block plus a pair of identical spring members, the utility of the invention is considerably extended with respect to the number of circuit paths accommodated. The principal advan-,

tages theretofore described with respect to the embodiment of FIGURE 2 are carried forth in the embodiment shown in FIGURE 10. In both of the above embodiments, as well as in the following commoning block embodiment, all conductive material isdisposed well within a protective overhang of dielectric material. In all embodiments the principal faces defining "the latching of terminals are metal rather than one face metal and an opposing face dielectric.

Turning now to yet a further embodiment of the invention, FIGURES 14, 15 and 16, show a connector commoning block adapted to accommodate numbers of terminal paths apart from any use with a printed circuit card. In FIGURE 14, a contact spring assembly 300 is shown to include a one-piece metal stamping with identical individual spring members 301 joined by an integral bus formed of

bars

310 and 314. The composite assembly including numbers of members 30, is adapted to be fitted within a common insulating housing 330 shown in FIGURES 15 and 16.

As can be seen in FIGURE 14, each member 300', is comprised of a body portion 302 having a central forward extension 303, including locking spring 304 and a latching spring assembly 305, which is essentially identical in function and arrangementto the locking and latching structure shown in FIGURES 2, 4 and 8. Extending along each side of 303 are walled channels, such as 306, each defining a receptacle similar in function to the

receptacles

80 and 81, described with respect to FIGURE 5. Positioned within the receptacle formed by channel 306 is a terminal spring member 307 which is identical in structure and similar in function to the spring member 120 described with respect to FIGURE 4. The operation of each spring member such as 307, with respect to the contact of a tab terminal, is reversed from that shown in FIGURES 6, 7 and 8, in that the insertion is from the opposite end of the spring as indicated in FIGURE 14 by the dotted line, with respect to tab terminal 308. The channel 306, includes in its lower wall, an embossment similar to that shown in FIGURES 6, 7 and 8, to define an axis of insertion along the geometrical center of the channel in the same manner as shown in FIGURE 8. With the blade of the tab terminal 308, fully inserted within channel 306, the contact innerface between the tab blade and the spring member and lower embossment is essentially as shown in FIGURE 8, with'the blade, of course, relatively oppositely oriented. The latching feature is as shown in FIGURE 9, with the latching stop 309 engaged under the adjacent spring member of assembly Formed from assembly 300, and extending out of the channels defining tab receptacles are

integral bus members

310 and 314. The forward bus member 310 includes a bevelled and downwardly formed portion 312 to permit clearance at the point of insertion of the tab terminal and thus avoid any possibility of interference with terminal insertion. The rearportion of 302 includes a transverse wall 316 relieved as at 318 to cooperate with the interior surfaces of a complementary cavity in an insulating block housing.

The housing shown as 330' in FIGURES 15 and 16 is a one-piece molding of thermosetting material such as glassfilled diallyl phthalate comprised of the

side walls

334 and 336 connected by a common back wall 335 and including a dividing wall 340. The housing 330 is, through such construction, capable of accommodating two assemblies 300 having members such as 301; it of course, being understood that the housing could be made in one half as along the dotted line of FIGURE 15 to accommodate a single strip of contact member. Extending inwardly from each

outer wall

332 and 336, are projections such as 334 and 338, which have a length to define

faces

335 and 337 spaced to receive the inner face of each assembly 305 and a contact spring 304 to lock the contact member and strip within the housing. The operation of each projection is identical to projection 32 described with respect to FIGURE 2. Projections 344 from wall 340 are included to provide support for each contact member.

As can be seen from FIGURES 15 and 16, each contact member or strip of contact members is inserted within the insulating block with the projections 344 fitted within the-space between adjacent spring members 301 and with the projections 334 fitted within the relief 318 down along member 303 to engage the contact spring 304 and the end of assembly 305 to lock the assemblies within the block.

With assemblies of the type shown in FIGURES 14, 15 and 16, commoned interconnections are provided between conductive leads attached to tab terminals inserted in any contact assembly.

As one of the advantages of the invention, attributable to the novel latching arrangement, the tooling required for insertion and withdrawal is greatly simplified. From the general description above given,- it will be apparent that no special tool is required to insert the tab terminals within the assembly. The conductive lead portion adjacent a tab terminal may be gripped and the terminal inserted in the appropriate aperture until the terminal stop is engaged and latched by the spring member. Due to the arrangement of parts, this insertion procedure may be done blindly without regard to polarization and with regard only to the orientation of the blade with repect to the slot; and orientation which is identical to aperture length.

FIGURE 17 shows a tool prepared for use in withdrawing tab terminals from the connector assemblies heretofore described. The tool 350 is comprised of a metal channel U-shaped along a substantial portion of its length and including at one end, a pair of

tynes

352 and 354. The tyne 352 is as shown in FIGURE 18, approximately twice the length of tyne 354, as measured from the body of the tool, and each is slightly less in width than an aperture such as 18 in FIGURE 1. Both tynes are relatively short as compared with prior art devices and for this reason tool breakage is substantially minimized and tool manipulation is simplified. As can be seen, the tool construction is quite simple although not fragile. In an actual embodiment, the tool was formed of spring steel sheet stock blanked to a fiat configuration and folded into the channel shape and thereafter spring tempered and given a protective coating of gun metal bluing. If desired, a handle as shown by the dotted line in FIGURE 17, may be provided on the end of the tool opposite to tynes 352 and 354, although such is not necessary for its use.

FIGURE 18 shows the operation of the tool in a preferred manner to extract a tab terminal. In such use one terminal at a time is extracted by positioning the tool as shown in FIGURE 18, with the longer tyne 352 inserted in a block aperture against the terminal to be withdrawn. The adjacent terminal may be extracted by merely reversing the tool and procedure indicated in FIGURE 18. During the extraction, the preferred manner for use of the tool is to grip the tool between the thumb and forefinger and firmly insert 352 fully inwardly to butt against the stop of the terminal; against 364 of 362. In this position, the spring member such as 366 of the contact member will be depressed. Then, with forefinger pressing the lead against the tool the terminal and lead can be then withdrawn, the bottom portion of the tyne acting to permit withdrawal of the terminal past the end face of the latching spring. As a part of the novel construction of tool 350, the lower tyne 354 serves to prevent misorientation of the tool such that 352 could be twisted to damage the latching spring member. The spacing between 352 and 354 is such as to place 354 lightly against the lower portion of the latching spring as the tool is fully inserted. The latching assembly and tool arrangement is such as to avoid stressing the contacts of the printed circuit board at any time during the above procedure.

In order to fully develop a preferred form of the invention, the foregoing description has been in considerable detail and should enable one skilled in the art to readily practice the various embodiments following the specification and drawings of the case. As will be appreciated by those skilled in the art, certain aspects of the invention may readily be directly employed to provide features identical in function and equivalent in structure. For example, with respect to the latching feature of the invention, the specification has detailed a receptacle and tab terminal configuration wherein the terminal is rectangular in cross-section and includes a blade contact surface. The concept of providing a latching spring which latches metal to metal rather than metal to a plastic part of a housing and includes a snubbing action may be adapted to receptacle and terminal configurations other than that shown. For example, the terminal blade could be of a cylindrical-or even tapered shape such as a solid pin, with a complementing receptacle having interior surfaces such as to receive the pin and further including at the base of the pin, a rim operating as the stop of the device. In such event the block housing cavities would be of a configuration such as to receive the alternative receptacle configuration.

In each of the embodiments above given a dual assembly has been shown capable of accommodating a pair of terminals. It is fully contemplated that half of the structure shown-could be'utilized to accommodate and latch a single terminal per contact spring assembly. As modified, this unit could be utilized with the commoning block embodiment or could include a single printed circuit contact spring of the configuration shown. In shown case the insulating block would merely be modified to support the assembly in a manner similar to that shown.

It has also been found useful to practice the invention in a form wherein there is a single cavity within an'insulating block including a single contact spring member of the type shown in FIGURE 2 as a test probe to printed circuit board devices or as a commoning path from a board upper conductive path to a board lower conductive path through a common conductive lead having the terminals at each end inserted in the receptacles of the spring member.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claim when viewed in their proper perspective against the prior art.

We claim:

In a tool for use in pulling terminals from the rear slots of a connector block of the type containing contact structures each including a pair of terminal receptacles in parallel relationship separated by a common projection carrying a pair of latches extending inwardly of said block and obliquely of the associated receptacle to latch terminals in associated leads in said structure the improvement comprising a one-piece metallic stamping of thin flat stock having a U-shaped body portion, a pair of parallel tines on one end of said body portion projecting axially.

therefrom, the said tines being spaced apart by a distance to fit over the said common projection and engage said latches, one of said tines being sufliciently longer than the other of said tines to deflect one latch inwardly before the other tine deflects its associated latch upon insertion of said tool within said block, the other tine serving to hold said tool in alignment by engagement with said latch during manipulation of said tool, the said tool further including a portion behind said tines to permit the lead of the terminal associated with a deflected latch to be held thereagainst to permit the said terminal and lend of'the deflected latch to be pulled from said block.

References Cited by the Examiner UNITED STATES PATENTS 2,252,816 8/ 1941 Santrey 29-27 8 X 2,63 8,025 5/ 1953 Nelson 29-270 2,978,800 4/1961 tBlain 29-203 3,087,235 4/ 1963 Porter 29-206 3,168,750 2/ 1965 Gattiker 29-203 WHITMQRE A. WILTZ, Primary Examiner. THOMAS H. EAGER, Examiner.