US3803710A - Method for retaining an electrical connector insert - Google Patents

Abstract

The insert of an electrical connector is held in the shell by forming outwardly projecting lugs on the insert that are rearwardly moved through longitudinal slots formed in the shell, followed by rotation of the insert to position the lugs between opposed shoulders on the shell, which thereby prevents relative axial movement of the shell and insert.

Description

United States Patent 1191 Clark Apr. 16, 1974 [54] METHOD FOR RETAINING AN 3,613,047 10/1971 KrOn 339/89 R ELECTRICAL CONNECTOR INSERT 3,611,260 10/1971 Colardeau. 339/89 R 3,470,524 9/1969 Culver 339/90 R [75] Inventor: Kenneth M. Clark, Beaumont, Calif. 2 90 542 9/1954 P ce t a1, 339/89 R 2,753,534 7/1956 Sprigg 339/59 M [73] Asslgnee' The name ."."P" 3,336,569 8/1967 I Nava 339/217 s cmfimnems 3,221,292 11/1965 Swanson et al... 339/217 s Cahf- 3,638,165 1/1972 Anhalt et a1. 339/59 R 3,478,305 11/1969 Chirumbolo 339/217 S [22] 1973 3,394,339 7/1968 Gaskievicz et a1 339/217 s [21] Appl. No.: 347,801

Related U.S. Application Data Primary Examiner-Charles W. Lanham [60] Division of Ser. N0. 167,317, July 29, 1971, Pat. NO. Assistant Examinerflames R- Duza" 3,727,172, which is a continuation-in-part of Ser. NO. Attorney, g or F1rmR1chard r 83,782, Oct. 26, 1970, abandoned.

[52] 11.8. C1. 29/629, 29/628, 29/630 B, ABSTRACT [511- nt Cl 2 2 The insert of an electrical connector is held'in the [58] Field or s elrl i fjn fif. 3 39/5 9 R 5 9 M 60 61 by fuming outwardly Pmjecmg 339/89 R 89 29/629 6 R sert that are rearwardly moved through longitudinal A B slots formed in the shell, followed by rotation of the insert to position the lugs between opposed shoulders [56] References Cited on the shell, which thereby prevents relative axial movement of the shell and insert. 1 I I UNITED STATES PATENTS 3,404,365 10/1968 Obeissart 339/90 R 6 Claims, 15 Drawing Figures 6 5 k y; 90 if if m H 9, man 6 w m ni i i? I, 64 i I'! 9/ 5 PATENTEDAPRIB I914 3803710 SHEET 3 OF 6 EF E PATENTED APR 6 1914 3; 803; 7 1 0 METHOD FOR RETAINING AN ELECTRICAL CONNECTOR INSERT REFERENCE TO RELATED APPLICATIONS:

This is a division of my copending patent application Ser. No. 167,317, filed July 29, 1971, for Electrical Connector, now U.S. Pat. No. 3,727,172, which is a continuation-in-part of application Ser. No. 83,782,

filed Oct.26, 1970, now abandoned.

BACKGROUND OF THE INVENTION:

1. Field of the Invention:

This invention relates to electrical connectors.

2. Description of Prior Art:

Electrical connectors conventionally include a plug and receptacle, each of which has an insert of dielectric material provided with multiple openings within which the electrical contacts are retained. The insert is introduced from the rearward end into a metallic shell, where it is held against an abutment by means of a nut. The nut is subject to loosening duringservice, so that there is no positive assurance of retention of the insert. Such loosening of the nut will allow the insert to move rearwardly even when the plug and receptacle are coupled, and can result in the separation of the contacts and the interruption of their electrical circuits. Also, this arrangement for retaining the insert wastes space within the shell, adding to the size of the connector.

SUMMARY OF THE INVENTION:

The present invention provides an improved electrical connector which overcomes the difficulties outlined above. In this connector, the insert is held in the shell by immovable abutments rather than a nut so that the insert will not become loosened while the connector is in service. This is accomplished by including spaced longitudinal grooves in the inner circumferential surface of the shell, which extend rearwardly from the forward end to an annular shoulder adjacent the rearward end. Circumferential recesses communicate with the longitudinal grooves and define additional abutments adjacent the annular shoulder. Lugs project outwardly from the insert and slide through the longitudinal grooves as the unit is assembled by moving the insert into the shell from the forward end. When the lugs have reached the annular shoulder, the insert is rotated to position the lugs in the circumferential recesses between the shoulder and the abutments. A suitable connection, such as bonding, holds the insert against reverse rotation. I

This construction means that the inserts cannot move rearwardly past the annular shoulder so that the inserts are held positively under vibrational and other loads imposed during use. Once the connector has been coupled, the inserts will remain fixed and cannot move so as to disengage the contacts. Also, by assembling the insert from the forward end, more available space is provided inside the shell, increasing the number of contacts that may be included in a connector of a given size. Virtually the entire interior dimension of the plug shell can be used in retaining contacts, allowing the receptacle shell, where excess space necessarily is present, to accommodate a comparably increased number of contacts.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a perspective view of an electrical connector made in accordance with this invention;

FIG. 2 is an exploded perspective view of certain portions of the connector, including in particular the parts used for coupling the plug and receptacle;

FIG. 3 is an enlarged longitudinal sectional view of the connector in the mated position;

FIG. 4 is an exploded perspective view, partially broken away, of the plug insert and shell;

' FIG. 5 is a transverse sectional view taken along line 5-5 of FIG. 3;

FIG. 6 is a transverse sectional view taken along line 66 of FIG. 3;

FIG. 7 is a fragmentary sectional view taken along line 77 of FIG. 5;

FIG. 8 is a fragmentary enlarged perspective view of one portion of the plug insert assembly, illustrating the contact retention fingers;

FIG. 9 is a fragmentary transverse sectional view taken along line 9-9 of FIG. 3;

FIG. 10 is an enlarged fragmentary view illustrating the details of the finger shape and its engagement with the contact;

FIG. 11 is a fragmentary longitudinal sectional view showing the retention finger spaced from the contact shoulder when the contact is shifted forwardly;

FIG. 12 is a further enlarged fragmentary view illustrating the engagement between the retention finger and the contact shoulder, with the contact under rearward load; I

FIG. 13 is an enlarged fragmentary longitudinal sectional view of the forward portions of the inserts of the plug and receptacle, shown slightly separated and illustrating the scaling arrangement for the openings;

FIG. 14 is a fragmentary flat pattern of the inside of the coupling ring, showing one of the bayonet grooves; and

FIG. 15 is an enlarged fragmentary sectional view .taken along line 15l5 of FIG. 3, illustrating the engagement of the spring tab on the snap ring and the forward end of the receptacle shell.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

Illustrated in the drawing is a multiple pin and socket connector that includes a plug 9 and a receptacle 10. The general arrangement for retaining the contacts is the same in the plug and receptacle. In the embodiment illustrated, the pin contacts are in the plug and the socket contacts in the receptacle, although this may be reversed if desired. The plug 9 includes a plug shell 11, which is a generally tubular metal member of circular cross section. Within the shell 11 is an insert assembly 12 that serves'to retain and hold a plurality of pin contacts 13. The insert assembly 12 includes disks l4 and 15 of a substantially rigid plastic. A suitable material for these members, because of its strength and temperature-resistance, is a polyarylsulfone marketed under the trademark Astrel" 360 plasthe radial end surface 57 fits behind the rearward shoulder 55 of the contact, while the inner end surface 58 of the finger rests upon the barrel 50 adjacent the shoulder 55.

The rearward transverse shoulder 55 of the contact 13 does not fall within a radial plane. Instead, it is inclined toward the forward end of the contact. Consequently, the shoulder 55 is undercut, being defined by a frustum of a cone. Desirable results are achieved when the shoulder 55 is inclined at around 12 relative to a radial plane. When the contact 13 is subjected to a force pushing it toward the rear, the undercut shoulder configuration and the inner finger surfaces 58 contribute greatly to the amount of force which can be absorbed before the retention fingers 42 will fail.

With the arrangement of this invention, the fingers 42, loaded as columns, receive the forces on them near the neutral centers of the columns, minimizing the tendency to buckle. The plastic of the fingers 42, being softer than the metal of the contact 13, becomes distorted where it engages the radially outer portion of the shoulder 55, as illustrated in particular in the enlarged view of FIG. 12. This has the effect of embedding the shoulder in the outer ends of the plastic fingers 42, stabilizing the finger ends. This increases the column strength of the fingers 42 because a column can withstand more loading if its ends are stabilized.

An additional stabilizing effect is realized because of the arcuate inner surfaces 58 of the fingers 42 substantially complementarily engaging the periphery of the barrel 50 of the contact adjacent the base of'the shoulder 55. This helps to anchor the free ends of the fingers. The inclined configuration of the shoulder 55 results in a force component on the fingers 42 helping to hold the surfaces 58 tightly against the circumference of the barrel 50 to enhance the column stabilizing effect.

The greater wall thickness of the fingers at their outer ends adds to their strength in shear andin bending. The bending strength resists the buckling of the fingers under load.

Another advantage comes from the fact that the inner corner 59 of the finger 42, between the end surface 57 and the inner surface 58, becomes spaced rearwardly from the fillet 60', which necessarily is formed between the shoulder 55 and the barrel 50 when the contact 13 is machined. When there is a straight radial shoulder, the inner corners of the retention fingers will engage the fillet at the base of the shoulder. This deflects the fingers outwardly, thereby tending to cam the fingers out of engagement with the shoulder. The

undercut shoulder 55 permits the finger to clear the fillet 60 without requiring a recess in the finger and without sacrifice in the strength of the fingers.

The insert assembly 61 for the receptacle includes a plastic disk 62 that is similar to the member 15. To it is bonded or otherwise suitably secured a forward cover disk 63. The members 62 and 63 also may be made of Astrel 360 plastic. Outwardly projecting lugs 64 on the disk 62 correspond to the lugs 18 on the member 15. The lugs 64 secure the insert assembly 61 to the receptacle shell 65 in the same way that the lugs 18 attach the insert assembly 12 in the plug shell 11. The insert assembly 61 isintroduced into the receptacle shell 65 by passing the lugs 64 through axial grooves in the inner surface of the receptacle shell 65,

whereupon subsequent rotation of the insert assembly 61 places the lugs 64 between opposed forward and rearward shoulders 66 and 67, respectively, in the receptacle shell. This holds the disk 62 and the cover element 63 within the receptacle.

The socket contacts 68 are retained in continuous separate openings 69 in the insert assembly of the receptacle, positioned against axial rearward movement by integral fingers 70 that project forwardly and inwardly from the insert disk 62. A shoulder 71 on the insert member 63, where the opening 69 reduces in width, is adjacent the forward end of the contact 68 and precludes forward movement of the contact. The fingers 70 are engageable with the rearward edge of the annular enlargement 72 on the socket contact. A wire 73 extends inwardly through an opening 74 in the rearward sealing member 75 of the receptacle 10 for each of the socket contacts 68. The end portions of the wires 73-are stripped of insulation and connected by crimping to the rearward barrel ends 76 of the socket contacts 68. When the forward ends 77 of the socket contacts receive the projecting pin portions 56 of the pin contacts 13 upon the mating of the connector, circuits are completed between the wires 51' and 73.

A rounded annular bead 78 projects outwardly from the forward radial face 79 of the cover disk 63 of the receptacle insertaround each of the openings 69. The bead 78 is engaged by the flat forward face 80 of the gasket 16 of the plug 9 when the connector is in the assembled position. Consequently, the bead 78 displaces the'resilient material of the gasket 16 and an efficient moisture seal is produced. This type of seal does not rely upon the entry of a projecting part of the resilient elastomer into a recess in the hard plastic of the mating part as in some prior-art designs. Unlike the previous designs, swelling of the gasket 16 from attack of fluids will not appreciably interfere with the mating of the connector so that the axial force required will not vary significantly under those conditions.

The mechanism for securing the plug and receptacle together in the mated position includes a coupling ring 81 that circumscribe the plug shell 11. The rearward end of the coupling ring includes a radially inwardly extending flange 82 in back of a rearwardly facing shoulder 83 on the plug shell. A snap ring 84 fits in an annular recess 85 in the intermediate portion of the inner circumferential wall of the coupling ring 81. The snap ring 84 is positioned in front of a forwardly facing radial shoulder 86 on the plug shell 11, cooperating with the flange 82 in retaining the coupling ring 81 on the plug shell 11. This allows the coupling ring 81 to rotate relative to the plug shell 11, but relative axial movement is prevented. I

Intermediate the snap ring 84 and the flange 82, the coupling ring 81 is provided with three short, arcuate, longitudinally extending recesses 87 in its inner surface 88 (see FIGS. 2 and 5). These recesses are adapted to receive the outer rounded portion 89 of a leaf spring 90. The latter member has normally straight legs 91 terminating in an inwardly bent end 92 which is received within a radial opening 93 in the periphery of the plug shell. This holds the spring to the plug shell 11. Adjacent the legs 91 of the spring 90 are flat chordal surfaces 94 which provide a clearance for permitting flexure of the spring 90.

By this construction, the coupling ring 81 can be rotated relative to the plug shell 11, but there is a detent action tending to prevent relative rotation when the portion 89 of the spring 90 enters a recess 87. This retaining force may be overcome by applying adequate torque to the coupling ring to cam the rounded spring portion 89 out of the recess 87, compressing the spring inwardly and allowing the spring portion 89 to slide along the circumferential surface 88 of the coupling ring intermediate the recesses 87.

Forwardly of the snap ring 84, three bayonet grooves 95 are formed in the inner circumferential surface 88 of the coupling ring. Each groove 95 includes a wide entrance opening 96 at the forward end 97 of the coupling ring, from which there extends an inclined portion 98 of the groove, leading to a circumferential inner part 99 of the groove. The axis of the latter portion of the bayonet groove 95, as best seen in FIGS. 2 and 14, falls entirely within a radial plane as there is no recess for the bayonet pin at the inner end 100 of the groove.

The receptacle shell 65 includes a forward portion 101 of enlarged diameter which provides clearance around the insert assembly 61. At the end of the forward portion 101 of the receptacle shell are three radially outwardly projecting bayonet pins 102. I

When the'electrical connector is to be mated, the forward end portion 103 of the plug shell 11 enters the forward portion 101 of the receptacle shell 65, fitting in the clearance spacearound the insert assembly 61 of the receptacle. Keys 104 on the plug shell fit in keyways 105 in the receptacle shell, assuring the proper rotational alignment of the plug and recep-tacle. With the keys in the keyways, the detent spring, when in a recess 87 in the coupling ring, positions the coupling ring so that the entrances 96 of the bayonet grooves 95 are aligned with the bayonet pins 102. Therefore, the bayonet pins 102 are brought to the entrances 96 of the bayonet grooves 95 in the coupling ring 81 as the plug and receptacle are advanced axially toward each other. Subsequent rotation of the coupling ring 81 moves the bayonet pins 102 through the inclined portions 98 of the grooves 95 and into the circumferential portions 99, drawing the plug and receptacle into the fully mated position. The coupling ring 81 is turned until the pins 102 are adjacent the inner ends 100 of the grooves 95, which occurs as the outer portion 89 of thespring 90 enters a detent recess 87 in the coupling ring. v

A positive stop is provided in one of the bayonet grooves to prevent rotation of the coupling ring 81 past the detent position when the connector is mated. This is accomplished by bending inwardly a small section 106 of the circumferential wall of the coupling ring, presenting an abutment surface 107 in the bayonet groove where it can be contacted by the bayonet pin at the termination of the rotation of the coupling ring 81 (see P16. 6). This location corresponds to the positioning of the outer portion 89 of the detent spring 90 in a detent receptacle 87. An opening 108 is formed in the wall of the coupling ring'adjacent the stop 107, while two additional openings 109 in the coupling ring are spaced 120 from the opening 108. This permits in the inner portions of the bayonet slots and that the plug and receptacle are coupled properly.

By this arrangement, the plug and receptacle are advanced axially toward each other the maximum distance when the bayonet pins are adjacent the ends 100 of the grooves 95 that receive them. No outward movement occurs as the connection is made, and, when the bayonet pins 102 reach the circumferential portions 99 of the grooves 95, the parts are held in their position of full maximum engagement. Even though subjected to a separating force, no relative movement of the plug and receptacle can take place, so that electrical continuity through the contacts is assured. The bayonet pins 102 are held against the forward sides of the bayonet grooves 95 when separating forces are imposed, while-the coupling ring 81 is prevented from movement axially by the engagement of the flange 82 with the rearwardly facing shoulder 83 of the plug shell 11. This provides a solid connection of the parts I g When the connector is in the fully mated position, the forward outer periphery of the forward end of the plug shell 11 engages an annular seal 110. The latter member is heldin an annular groove 111 in the receptacle shell 65 by bonding.

in some instances, the snap ring 84 may be provided with forwardly projecting tabs 113 that are brought into engagement with the end of the forward portion 101 of the receptacle shell 65 when the connector is mated (see FIG. 15). This puts a desirable tension on the coupled plug and receptacle, eliminating any clearance in the coupling mechanism. This also makes an electrical connection between the plug shell 11 and the receptacle shell 65.

The plug and receptacle are disconnected by reverse rotation of the coupling ring 81 to free the bayonet pins 102 from the bayonet grooves 95. As this is accomplished, the detent spring is forced out of one detent recess 87, and its central part 89 slides along the surface 88 of the coupling ring 81 to the next detent recess 87. In the latter detent position, the bayonet pins 102 have reached the entrances 96 to the grooves and the plug and receptacle may be pulled apart axially.

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.

I claim:

1. The method of assembling a dielectric insert and a tubular shell of an electrical connector comprising the steps of providing a tubular shell having a forward end and a rearward end,

providing a first substantially radial forwardly facing abutmentin said shell at a location remote from said forward end,

providing a second substantially radial rearwardly facing abutment in said shell spaced forwardly of said first abutment and with said second abutment being positioned so as to leave space within said shell laterally adjacent said second abutment,

providing a dielectric member with an exterior dimension such that it is adapted to be received substantially complementarily in said shell,

providing an outwardly projecting lug on said dielectric member such that said lug has substantially radial forward and rearward edges and a lateral dimension no greater than that of said space and a distance between said edges substantially the same as the distance between said first and second abutments, moving said dielectric member into said shell from said forward end toward said rearward end so as to move said lug through said space past said second abutment, and then rotating said dielectric member relative to said shell so as to position said lug between said first and second abutments. 2. The method as recited in claim 1 including in addition the step of securing said dielectric member against rotation relative to said shell following said positioning of said lug between said first and second abutments so as to prevent said lug from being moved rotationally from between said first and second abutments.

3. The method as recited in claim 2 in which for said securing of said dielectric member said dielectric member is bonded to said shell.

4. The method of producing a section of an electrical connector comprising the steps of providing a tubular shell of'cylindrical cross section having a forward end and a rearward end, I

providing a substantially radial forwardly facing annular shoulder in said shell adjacent said rearward end,

providing a plurality of circumferentially spaced substantially radial rearwardly facing abutments in said shell opposite from and forwardly of' said an nular shoulder so as to pro-vide circumferential recesses between said abutments and said annular shoulder,

and to provide a plurality of circumferential spaces between said abutments, providing a dielectric member of circular cross section substantially of the same diameter as the interior of said shell having a plurality of openings extending longitudinally therethrough, providing a plurality of radially outwardly projecting circumferentially spaced lugs on the periphery of said dielectric member with said lugs having lateral dimensions such that they are adapted to fit within said spaces between said abutments, and with said lugs having substantially radial forward and rearward edges and dimensions between said edges longitudinally of-said dielectric member substantially complementary to the spacing between said abutments and said annular shoulder, moving said dielectric member into said shell from said forward end of said shell toward said rearward end of said shell so that said lugs pass through said spaces between said abutments and are brought into adjacency with said annular shoulder, and then rotating said dielectric member relative to said shell without imparting any substantial relative longitudinal movement to said dialectric member and said shell so. as to position said lugs between said abutments and said annular-shoulder.

5.1116 method as recited in claim 4 including in addition the step of providing a longitudinally forwardly extending portion on the side of one of said lugs, and in which said dielectric member is so rotated relative to said shell to a position where said portion of said lug engages the side of one of said abutments.

6. The method as recited in claim 5 in which in forming said rearwardly facing abutments longitudinally extending grooves are provided in said shell extending from said forward end to said annular shoulder, said grooves defining said circumferential spaces between said rearwardly facing abutments.

Claims (6)

1. The method of assembling a dielectric insert and a tubular shell of an electrical connector comprising the steps of providing a tubular shell having a forward end and a rearward end, providing a first substantially radial forwardly facing abutment in said shell at a location remote from said forward end, providing a second substantially radial rearwardly facing abutment in said shell spaced forwardly of said first abutment and with said second abutment being positioned so as to leave sPace within said shell laterally adjacent said second abutment, providing a dielectric member with an exterior dimension such that it is adapted to be received substantially complementarily in said shell, providing an outwardly projecting lug on said dielectric member such that said lug has substantially radial forward and rearward edges and a lateral dimension no greater than that of said space and a distance between said edges substantially the same as the distance between said first and second abutments, moving said dielectric member into said shell from said forward end toward said rearward end so as to move said lug through said space past said second abutment, and then rotating said dielectric member relative to said shell so as to position said lug between said first and second abutments.

2. The method as recited in claim 1 including in addition the step of securing said dielectric member against rotation relative to said shell following said positioning of said lug between said first and second abutments so as to prevent said lug from being moved rotationally from between said first and second abutments.

3. The method as recited in claim 2 in which for said securing of said dielectric member said dielectric member is bonded to said shell.

4. The method of producing a section of an electrical connector comprising the steps of providing a tubular shell of cylindrical cross section having a forward end and a rearward end, providing a substantially radial forwardly facing annular shoulder in said shell adjacent said rearward end, providing a plurality of circumferentially spaced substantially radial rearwardly facing abutments in said shell opposite from and forwardly of said annular shoulder so as to pro-vide circumferential recesses between said abutments and said annular shoulder, and to provide a plurality of circumferential spaces between said abutments, providing a dielectric member of circular cross section substantially of the same diameter as the interior of said shell having a plurality of openings extending longitudinally therethrough, providing a plurality of radially outwardly projecting circumferentially spaced lugs on the periphery of said dielectric member with said lugs having lateral dimensions such that they are adapted to fit within said spaces between said abutments, and with said lugs having substantially radial forward and rearward edges and dimensions between said edges longitudinally of said dielectric member substantially complementary to the spacing between said abutments and said annular shoulder, moving said dielectric member into said shell from said forward end of said shell toward said rearward end of said shell so that said lugs pass through said spaces between said abutments and are brought into adjacency with said annular shoulder, and then rotating said dielectric member relative to said shell without imparting any substantial relative longitudinal movement to said dialectric member and said shell so as to position said lugs between said abutments and said annular shoulder.

5. The method as recited in claim 4 including in addition the step of providing a longitudinally forwardly extending portion on the side of one of said lugs, and in which said dielectric member is so rotated relative to said shell to a position where said portion of said lug engages the side of one of said abutments.

6. The method as recited in claim 5 in which in forming said rearwardly facing abutments longitudinally extending grooves are provided in said shell extending from said forward end to said annular shoulder, said grooves defining said circumferential spaces between said rearwardly facing abutments.

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