US3475720A - Electrical connecting device - Google Patents

Description

Oct. 28, 1969 P. c. CULVER 3,4753% ELECTRICAL CONNECTING DEVICE Filed May 15, 1967 3 Sheets-Sheet 2 4 V INVENTOR 3 Sheets-Sheet l Filed May 15, 1967 M QM. NN Q\ 1969 P. c CULVER ELECTRICAL CONNECTING DEVICE 3 Sheets-Sheet :5

Filed May 15,

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United States Patent 3,475,720 ELECTRICAL CONNECTING DEVICE Perrin C. Culver, Banning, Calif., assignor to The Deutsch Company Electronic Components Division, Banning, Califi, a corporation of California Filed May 15, 1967, Ser. No. 638,459 Int. Cl. H01r 9/08 US. Cl. 339-217 13 Claims ABSTRACT OF THE DISCLOSURE An electrical connecting device including a body of rigid dielectric material having a. bore receiving a retainer member held in place by shoulders of defiectable spring fingers at either end of a reduced diameter portion of the bore, the retainer member having at least one inwardly inclined resilient tab engaging a shoulder on a contact, the tab having an outwardly bent end to facilitate release, the contact having a portion of reduced diameter adjacent its shoulder providing an increased bearing area for the tab.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to electrical connecting devices.

The prior art Certain multiple pin-and-socket electrical connectors, terminal junctions and the like incorporate the rear-release type contact retention system. In the rear-release system, the contact is inserted, released and removed from the rearward end, with no access to the forward end being required. This facilitates the assembly and maintenance of the connector. It also permits standardization of connector and contact design, assembly tools and techniques.

In a typical connector of the prior art, there is a body of hard plastic material provided with a plurality of parallel bores through it for receiving the electrical contacts.

The connector is in two sections, one for holding the pin contacts and the other retaining the socket contacts which mate wth the pins when the connector is joined. Each of the bores includes an annular recess to hold a retaining clip that, in turn, engages thecontact. The retaining clip is a split cylindrical member having a circumferential wall bearing against the recess, while its ends are adjacent the shoulders at the ends of the recess where the bore reduces to its normal diameter. Each retainer clip includes one or more integral spring tabs, which incline forwardly and inwardly to fit behind a shoulder on the contact. This holds the contact against movement in the rearward direction, While the plastic material provides a shoulder adjacent an additional contact shoulder to preclude movement in the forward direction.

In order to allow installation of the retainer clips, the plastic bodies are made in two pieces bonded together at one end of the recess. The bonding occurs after the retainer clips have been installed in one of the sections of the plastic. This two-piece construction inherently is relatively expensive in view of the necessity for the two parts and the bonding step in the manufacture of the connector. Moreover, when the bond is effected, the bonding agent sometimes is squeezed out into the bores, damaging the retainer clips.

It is necessary to construct these connectors so that the contacts are removable. This is accomplished through the insertion of a tubular tool into the bore for engaging the inwardly inclined spring tabs. As the tool is moved forwardly, the tabs are pried outwardly to clear the shoulders of the contacts so that the contacts may be pulled from the connector body. It is difficult to secure adequate outward travel of the ends of the spring tabs in order that they may be expanded outwardly a distance sufiicient to allow the contact shoulders to pass through them. This problem is made more severe by the small sizes frequently required for these connectors. In fact, this has limited the degree of miniaturization of the con nectors in which such retainer clips may be used successfully. Nevertheless, there is an increasing requirement for electrical connectors of reduced dimensions, with a definite trend toward extremely small sizes.

SUMMARY OF THE INVENTION The present invention provides an electrical connecting device in which even in small sizes the contact is fully releasable. Connectors may be made with maximum diameter bores for the contacts with minimum spacing between the bores. Also, the connectors are of one-piece plastic construction so that bonding is unnecessary.

The electrical connector of this invention includes a body of rigid dielectric material, having a bore for each of the contacts which it receives. Each bore includes a portion of reduced diameter. The retainer clip has fingers as its forward end, which may be compressed to allow the clip to pass the reduced diameter portion of the bore. The projecting ends of the fingers are doubled over outwardly to provide a forward shoulder. Opposed shoulders are provided at the bases of the fingers where they are bent inwardly. These shoulders fit next to the shoulders at the ends of the reduced diameter portion of the bore, holding the clip in place. The doubled-over forward spring finger ends result in inclined surfaces permitting the clip to be installed simply by pushing it inwardly from the rear, as the inclined surfaces cam the fingers inwardly to deflect them as the reduced diameter portion is passed. The fingers stabilize the contacts laterally when the assembly is complete.

The retainer clip includes forwardly and inwardly inclined integral spring tabs having ends adapted to fit behind shoulders on the contacts. These ends of the tabs are bent outwardly from the line of inclination, to be made approximately parallel to the axes of the clips. This means that when the tabs are deflected outwardly by the removal tool their ends assume a position sloping outwardly and forwardly. This raises their forward edges and presents inclined surfaces adjacent the contact shoulders. Consequently, the shoulders easily move past the tab ends, defleeting the tabs further as necessary as they engage the inclined end surfaces. Preferably, the contact shoulders adjacent the tab ends are provided with beveled outer edges to facilitate the movement of the contact shoulders past the spring tabs upon removal.

Also, particularly for the smaller sized connectors, the contacts may be reduced in diameter adjacent the shoulders to increase the shoulder widths and provide an adequate bearing area, increasing the ability of the retainer clips to hold the contacts against rearward push-out forces. At the same time, the localized reduction in diameter of the contacts does not require reduction in the diameter of the barrels of the contacts which receive the wires that are attached to them. Therefore, they are able to be associated with full-sized wires.

An object of this invention is to provide an improved electrical connecting device.

Another object of this invention is to provide an electrical connector adapted for construction in small sizes.

A further object of this invention is to provide an electrical connector in which contact removal is facilitated.

An additional object of this invention is to provide an electrical connector having a one-piece body of rigid dielectric material.

Another object of this invention is to provide an electrical connector having improved contact retention.

Yet another object of this invention is to provide an electrical connector in which the contact is stabilized against lateral deflection.

An additional object of this invention is to provide an electrical connector device in which the contacts are mounted in a closely spaced relationship.

A still further object of this invention is to provide an electrical connector that is cheaper and easier to make than conventional designs.

These and other objects will become apparent from the following detailed description taken in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a fragmentary longitudinal sectional view of an electrical connector incorporating the present invention;

FIGURE 2 is an enlarged fragmentary longitudinal sectional view of a portion of the connector of FIGURE 1;

FIGURE 3 is an enlarged perspective view of one of the retainer clips;

FIGURE 4 is an end elevational view of the retainer clip;

FIGURE 5 is a plan view of the flat pattern of the retainer clip before it is bent to its cylindrical configuration;

FIGURE 6 is a fragmentary longitudinal sectional view of the connector during installation of a contact; and

FIGURE 7 is a view similar to FIGURE 6, with the spring tabs of the retainer clip deflected for contact removal.

DESCRIPTION OF THE PREFERRED EMBODIMENT The two mating sections 10 and 11 of the electrical connector of this invention are shown in the engaged position in FIGURE 1. The section 10 includes a body of dielectric material 12, which normally is made of hard plastic, on the rearward end of which is bonded a member 13 of soft resilient rubber, while a thinner resilient pad 14 is bonded to the opposite end. The latter element, when the connector sections are joined, engages the front edge of the body 15 of rigid dielectric material of the connector section 11, which corresponds generally to the plastic member 12. The resilient rubber element 16 secured to the end of the plastic body 15 is similar to the member 13 of the connector section 10. The assembled elements of the connector section 10 have a bore 18 which is aligned with and connects to a bore 19 in the section 11 when the connector is mated. Only a fragment of the entire connector is illustrated, and in the complete unit normally there are many of the bores 18 and 19. A multiple pin-and-socket connector is shown, but the invention is applicable as well to terminal junctions, feedthroughs and other electrical termination devices.

Received in the bore 18 of the connector section 10 is a pin contact 20 having a projecting end 21 extending into the end 22 of a socket contact 23 that is located in the bore 19. A retainer clip 24 holds the contact 20 in the bore 18. Another retainer clip 24 secures the contact 23 in the bore 19, because the contacts 20 and 23 are similar in configuration other than at their end portions 21 and 22.

A wire 26 extends through the bore in the resilient member 13 to connect to the contact 20. A section of the insulation 27 of the wire 26 is removed adjacent the contact 20, so that the bare metal strands 28 extend into the barrel end 29 of the contact 20, which is provided with a cyclindrical opening 30 to receive the wire. The barrel end 29 is suitably secured to the wire strands 28, such as by crimping or soldering. A gap 31 is left between the end of the insulation 27 and the end of the barrel section 29 of the contact. The entrance to the bore 18 is sealed around the wire 26 by means of the inwardly extending annular ribs 32, 33 and 34 in the bore of the resilient rubber disc 13, which bear against the surface of the wire 26.

A wire 35 similarly extends'through the resilient element 16 to connect to the barrel end 36 of the socket contact 23. When the -conneeton-is mated as shown in FIGURE 1, a circuit is completed between the wires 26 and 35 through the connection between the ends 21 and 22 of the contact 20 and 23.1, U

With reference now to FIGURES.3, 4 and 5,, the retainer members 24 are of resilient sheet metal material formed into a generally cylindrical shape. Initially, the sheet metal is punched to provide the flat pattern shown in FIGURE 5, which then is rolled to the shape shown in FIGURES 3 and 4. Progressive die forming permits the rapid economical fabrication of the retainer clips 24. Generally, these clips will be made of thin material such as a sheet of beryllium copper .004 inch thickness.

At one end of the retainer member 24 are four fingers 37 substantially equally spaced around the periphery of the clip with gaps 38 between adjacent fingers. The distal ends of the fingers 37 are bent outwardly and back to form doubled-over portions 39. Inwardly of the ends 39, the fingers 37 are straight longitudinally, but are provided with offset sections 40 where they join the main cylindrical body 41 of the retainer. The offset portions 40 incline radially inwardly and axially forwardly from the cylindrical body 41, so that the inner surfaces 42 of the fingers 37 are closer to the axis of the retainer clip than the inner circumferential surface of the main cylindrical portion 41.

The retainer clip 24 also includes a pair of opposed inwardly directed spring tabs 43. For the major portions of their lengths, the walls 44 of the tabs have a substantially constant inclination inwardly and toward the forward end of the retainer clip. The ends 45 of the tabs 43, however, are given a reverse bend so that they are approximately parallel to the axis of the retainer clip 24.

The bores 18 and 19 in the hard plastic members 12 and 15 are provided with short reduced diameter portions 46 and 47 which cooperate with the fingers of the retainers 24 in holding the retainers within the members 12 and 15. As seen in particular in the enlarged illustration of FIGURE 2, the reduced bore portion 46 is bounded at the rearward end by an inclined shoulder 48 and at the forward end by a radial shoulder 49. When the clip 24 is installed, the outwardly facing shoulder defined by the inclined offset sections 40 of the fingers 37 is disposed adjacent the similarly inclined shoulder 48 of the member 12. The edges 50 of the doubled-over ends 39 of the fingers 37 provide additional shoulders adjacent the shoulder 49 of the member 12. With the main portions of the fingers 37 extending through the reduced diameter section 46, which is of substantially the same diameter as the outer diameters of the fingers, and the shoulders in juxtaposition, the clip 24 is retained axially in the dielectric body 12.

Installation of the clip 24 is accomplished very easily by pushing it into the bore 18 from the rearward end, normally before the attachment of the resilient sealing pad 13. The rounded forwards ends of the fingers are cammed inwardly by the engagement with the inclined shoulder 48, compressing the fingers to pass through the reduced diameter portion 46. The gaps 38 between adjacent fingers allow them to be deflected inwardly in this manner. As soon as the doubled-over portions 39 pass the shoulder 49 of the plastic body 12, the fingers snap outwardly and the installation is complete. In order to assure the snap-in connection, the spacing between the edge 50 of the doubled-over ends and the offset sections 40 is made slightly longer than the spacing between the shoulders 48 and 49. In actual practice, this amounts to an almost infinitesimal amount of axial float for the retainer clip.

Inwardly of the projecting end 21 that enters the mating socket contact, the pin contact 24 includes a cylindrical part 52 that is larger in diameter than the end 21. The fingers 37 of the retainer clip 24 surround the portion 52 of the contact, being closely spaced from it so as to provide lateral stability to the contact. An inclined shoulder 53 connects to the rearward end of the section 52 of the contact and leads to a larger short cylindrical portion 54. At the rearward end of the latter section is a beveled edge 55 inwardly from which extends a radial shoulder 56. The inner edge of the shoulder 56 connects to a short cylindrical section 57 considerably reduced in diameter. A frustoconical surface 58 extends from the portion 57 to the barrel part 29 of the contact. The opening 30 that receives the conductor 28 of the wire stops short of the frustoconical portion 58.

The contacts are installed by means of a split tubular tool 60, the end of which is illustrated in FIGURE 6. The tool 60 fits in back of the rearward edge of the barrel portion 29 of the contact 20, circumscribing the conductor 28 at the gap 31 where the insulation 27 has been removed. The contact is pushed forwardly into the bore 18, bringing the forward inclined shoulder 53 into engagement with the inwardly sloping portions 44 of the tabs 43. Continued forward movement of the contact cams the tabs 43 outwardly, allowing the enlarged portion 54 to move axially through the clip. As soon as the ends 45 of the tabs are passed, the tabs snap inwardly to the position of FIGURES 1 and 2 in back of the radial shoulder 56. This positions the contact 20 against movement toward the rear.

As the contact is positioned in this manner, the forward inclined shoulder 53 is brought to a position adjacent the offset portions 40 of the fingers 37. The olfset sections 40 provide inwardly facing shoulders which limit forward travel of the contact. Thus, the contact 20 is retained in the insulating block 12 against axial movement in either direction. Moreover, the fingers 37, by circumscribing the forward cylindrical section 52 of the contact, provide lateral stability for it. This assists in maintaining the positions of the projecting pin ends 21 so that they will be assured of entering the openings in the ends 22 of the mating socket contacts 23.

The construction of the rearward portions of the contact 23 is similar to that of the contact 20, and installation of the contact 23 is effected in the same manner as that for the contact 20.

The contact is held in the insulation block so that it resists high axial loading tending to push the contact out to the rear. This is true despite manufacture of the parts to very small dimensions. The reduced diameter part 57 of the contact 20 allows it to have a relatively wide radial shoulder 56. This permits the ends 45 of the tabs 43 to make firm engagement with a wide flat surface in retaining the contact in the plastic body. At the same time, by being forwardly of the barrel 29 of the contact, the opening 30 is not reduced in width and the contact accepts a full-diameter wire. The portion 57 can be made much smaller with attendant increase in the width of the shoulder 56 because of being located ahead of the opening 30in the barrel. In conventional designs, the openings for the conductors extend almost to the shoulders of the contacts so that no reduction in diameter and increase in shoulder width is possible.

Contact removal is accomplished by the split tubular tool 62, the end portion of which is illustrated in FIG- URE 7. The tool 62 is inserted into the bore 18 and is dimensioned to fit within the main cylindrical portion 41 of the retainer clip 24. As the tool 62 is advanced, it engages the inclined surfaces 44 of the tabs 43, deflecting them outwardly. Available deflection is limited, however, because of the small dimensions of the parts and the minute clearance between the end section 29 of the contact 20 and the retainer clip 24. Nevertheless, disengagement of the ends 45 from the shoulders 56 is accomplished without difi'iculty. This occurs because, as the tabs 43 are deflected outwardly, the end sections 45 of the tabs no longer are parallel to the axis of the retainer clip. Instead, they assume an outward inclination, as seen in FIGURE 7, causing them to slope away from the shoulder 56. This facilitates the ability of the enlarged portion 54 of the contact to pass through the tabs. Any engagement between the portion 54 of the contact and the ends 45 of the tabs merely deflects the tabs outwardly because of their inclination, rather than blocking movement of the contacts.

Removal of the contact also is aided by the beveled edge 55 between the shoulder 56 and the enlarged part 54. This beveled edge helps the tab ends 45 to slide over the periphery of the portion 54 of the contact without obstruction. In other words, the enlarged portion of the contact has a tapered entrance portion which assists its movement into the space between the opposed spring tabs 43 so that it can be pulled from the connector by the wire 26. Thus, even when made in very minute sizes, the contacts are fully releasable. The provisions of inclined tab ends and beveled edges are useful in larger connectors as well in assuring that contact removal is accomplished without difficulty.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

What is claimed is:

1. An electrical connector device comprising a body of substantially rigid dielectric material,

said body having a rearward end and a forward end,

said body having a bore extending from said rearward end toward said forward end,

an electrical contact in said bore,

said electrical contact having a forward end for engaging a mating contact and completing an electrical circuit, and a rearward end for receiving and being attached to an electrical conductor, said contact having an enlarged portion intermediate said forward and rearward ends,

a rearward shoulder at the rearward end of said enlarged portion, and a forward shoulder at the forward end of said enlarged portion, a retainer member in said bore,

said retainer member including a portion adjacent the wall of said bore, and at least one resilient tab inclined inwardly and forwardly from said portion,

said tab having an end portion engaging said rearward shoulder of said contact, said end portion of said tab being more nearly parallel to the axis of said bore than remaining portions of said tab, said retainer member having a plurality of spring fingers projecting from the forward end thereof, said spring fingers being offset adjacent said retainer member to provide an inwardly inclined inner shoulder adjacent said forward shoulder of said contact for preventing said contact from moving in the forward direction, said spring fingers having outwardly directed portions spaced from said offset so that said spring fingers provide opposed outer shoulders, said bore having a reduced diameter portion around said spring fingers and between said opposed outer shoulders,

whereby said opposed outer shoulders cooperate with said reduced diameter portion for holding said retainer member in said bore.

2. A device as recited in claim 1 in which for providing said outwardly directed portions said spring fingers have outwardly doubled-over distal ends, the edges of the doubled-over portions defining outer shoulders at the forward ends of said spring fingers.

3. A device as recited in claim 1 in which said contact has a reduced diameter intermediate said rearward end and said enlarged portion for providing said shoulder at said rearward end of said enlarged portion with a greater width.

4. A device as recited in claim 1 in which said enlarged portion adjacent said rearward shoulder thereof is tapered inwardly and rearwardly for facilitating movement of said enlarged portion past said tab upon deflection of said tab outwardly for removal of said contact from said retainer member.

5. A device as recited in claim 1 in which said portion of said bore of reduced diameter provides a rearward shoulder inclined inwardly and forwardly for facilitating deflection of said spring fingers upon advancement of said retainer member forwardly upon installation of said retainer member into said bore.

6. An electrical connector comprising a body of substantially rigid dielectric material,

said body having a rearward end and a forward end, said body having a bore extending from said rearward end to said forward end,

said bore having a portion of reduced diameter providing a substantially radial forward shoulder, and a rearward shoulder inclined forwardly and inwardly, a retainer member of resilient material,

said retainer member including a longitudinally split tubular portion bearing against the periphery of said bore rearwardly of said portion of reduced diameter, a plurality of fingers projecting from the forward end of said tubular portion,

each of said fingers having a rearward portion adjacent said tubular portion which is offset to incline inwardly and forwardly, said offset portion being adjacent said rearward shoulder of said body, the forward ends of said fingers being doubled over outwardly to provide rearwardly facing edges adjacent said forward shoulder of said body,

whereby said offset portions and said doubledover portions cooperate with said rearward and forward shoulders for retaining said retainer member axially within said bore, and a resilient tab inclined inwardly and forwardly from said tubular portion, and a contact,

said contact being in said retainer member in said bore, said contact having an enlarged portion defining a forward shoulder inclined inwardly and forwardly, and a rearward shoulder,

said forward shoulder being adjacent said offset portions of said fingers for e thereby precluding movement of said contact in a forward direction, said tab including an end engaging said rearward shoulder of said contact, said tab having a substantially constant inclination toward said end and adjacent said end being more nearly parallel to the axis of said tubular portion,

whereby upon subsequent deflection of said tab said portion adjacent said end frees said rearward shoulder of said contact for permitting removal of said contact in a rearward direction. 7. A device as recited in claim 6 in which said contact forwardly of said enlarged portion and inwardly of said fingers is closely spaced from said fingers, whereby said L I I" r fingers provide lateral stability or the forwardshoulder of said contact. l

8. A device as recited in claim 6 in which said contact at said enlarged portion includes a beveled edge tapering rearwardly and inwardly interconnecting the circumference of said en1arged,portion and rearward shoulder of said contact for facilitatingmovement of said contact rearwardly past said tabupon deflectionof .said tab.

9. A device as recited inelaim 6 in which said contact rearwardly of said enlarged portion includes a barrel having an axially extending opening therein, and including in addition a wire extending into said opening and secured to said contact in said opening, said contact intermediate said barrel and said enlarged portion having a frustoconical portion for providing said contact adjacent ,said rearward shoulder of said contact with a smaller diameter for therebyincrea'siiig the width of said rearward shoulder of said contact.

10. A device as recited in claim 9 Q which said wire has insulation thereon except for said portion'extending into said barrel and a portion adjacent the' rearward end of said barrel for defining a gap permitting engagement of said rear-ward shoulder of said contact by a tool for inserting said contact into said retainer member.

11. An electrical connector comprising a body of substantially rigid dielectric material,

said body having a rearward end and a forward end, said body having a bore extending from said rearward end toward said forward end, an electrical contact in said bore,

said contact having a shoulder facing said rearward end, a retainer member, g

said retainer member having a resilient tab inclined inwardly toward the axisof said bore and forwardly toward said forward end,

said tab having a forward end portion engaging said shoulder for holding said contact against movement relative to said body toward saidzrearward end, said end portion of said tab being more nearly parallel to the axis of said bore than other portions of said tab for facilitating separation of said end portion from said shoulder upon subsequent outward deflection of said tab, said bore being provided with a portion of reduced diameter, 1 said retainer member having a plurality of spring fingers at the forward end thereof deflectable to pass through said portion. of reduced diameter,

said spring fingers having opposed shoulders disposed at either end of said portion of reduced diameter for cooperating with said portion-of reduced diameter to. hold said ,retainer memb rinsaid bore, and means-holding .said contact gagainst movement toward said forwardend. Q i ,12. Anelectrical connector comprising 1 a body havinga bore therein, a contact in said bore,

'-said contact havinguarearward endjorcngagihg a wire, a forward end for engaging electric-ally conductive member, and an intermediate enlarged portion defining a forward and a rearward shoulder, and a sleeve member in said bore;

said sleeve member including a portion inclined radially inwardly,

thereby providing an abutment adjacent said forward shoulder of said contact for preventing axial movement of said contact relative to said sleeve member in one direction, a plurality of fingers projecting axially beyond said inwardly inclined portion,

said fingers having distal end portions doubled over outwardly thereof, and resilient tab means inclined radially inwardly to a position adjacent said rearward shoulder for preventing axial movement of said contact relative to said sleeve member in the opposite direction. 13. A contact retainer device comprising a tubular member of sheet metal,

said member being longitudinally split, said member adjacent one end thereof including a radially inwardly inclined portion thereby providing an inner shoulder engageable with an abutment on an electrical contact received in said tubular member and an outer shoulder engageable with an abutment on a part receiving said tubular member, said member beyond said radially inclined portion including a plurality of longitudinally extending resilient fingers,

the distal ends of said fingers being doubled over and overlying the exteriors of the principal portions of said fingers, thereby presenting edges of said doubled-over ends engageable with an abutment on a part receiving said tubular member, said member including resilient tab means inclined radially inwardly and longitudinally toward said one end,

said tab means having end portions spaced from said radially inwardly inclined portion for engagement with another abutment on a contact received in said tubular member.

References Cited UNITED STATES PATENTS 1,553,188 9/1925 Sauton 292-318 2,477,849 8/ 1949 Adams 339217 3,144,288 8/1964 Grant 339-217 X 3,158,424 11/1964 Bowen 339-217 3,325,773 6/ 1967 Hollingsead 339217 FOREIGN PATENTS 262,707 5/1964 Netherlands.

RICHARD E. MOORE, Primary Examiner

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