US3215972A

US3215972A - Electrical connector

Info

Publication number: US3215972A
Application number: US225677A
Authority: US
Inventors: Ernst A Eriksson
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-09-24
Filing date: 1962-09-24
Publication date: 1965-11-02
Anticipated expiration: 1982-11-02

Description

Nov. 2, 1965 v E. A. ERIKSSON ELECTRICAL CONNECTOR 3 Sheets-Sheet 1 Filed Sept. 24, 1962 INVENTOR.

fies 5 7/4, fem 550M BY P055275 C025 flrroewe/ Nov. 2, 1965 E. A. ERIKSSON ELECTRICAL CONNECTOR 3 Sheets-Sheet 2 Filed Sept. 24, 1962 INVENTOR.

EBA 5 7,4 Ez/zsso/v Hrrozws/ H'IHP" I /////l mild Nov. 2, 1965 E. A. ERIKSSON ELECTRICAL CONNECTOR Fiied Sept. 24, 1962 3 Sheets-Sheet S INVENTOR. fax/57x4 521K550 I I I In P w n? i BY Ease/er 5, C025 flrrozA/EY United States Patent 3,215,972 ELECTRICAL CONNECTOR Ernst A. Eriksson, 41 Preston Road, Lexington, Mass. Filed Sept. 24, 1962, Ser. No. 225,677 Claims. (Cl. 339-72) This application is a continuation-in-part of my copending application Serial No. 29,929, filed May 18, 1960, now Patent No. 3,056,941.

This invention relates to electrical connectors and more particularly to connectors for incorporation in lamps, plugs, fuses and the like, intended for use in internally threaded sockets.

The present invention, like that of the aforementioned application, is concerned with an electrical connector capable of being introduced into and withdrawn from a standard threaded electrical socket without rotation, while providing secure engagement between the connector and socket, effectively resisting withdrawal of the connector. The basic components of the connector, whether it comprise a lamp, fuse, plug or other device, are a generally cup-shaped body, a center contact member and a retaining member for engaging the threaded socket and providing a second electrical contact. The retaining member is in the form of a spider including a body or base mounted on or within the cup-shaped body, and two or more radially projecting, thread-engaging, resilient legs. The legs are deformable to permit insertion of the connector into the socket and being resilient and biased outwardly, engage the threads to retain the connector within the socket while permitting the connector to be withdrawn without rotation.

The present invention has as an object, the provision in an electrical connector of the type described, a novel and improved retaining element which permits introduction of the connector into a threaded socket with the application of relatively little force while requiring an appreciably greater, predetermined force to disengage said connector from said socket.

Another object of the invention is to provide in an electrical connector, a retaining element of the character described requiring rotation of the connector for removal thereof from a socket.

A further object of the invention is to provide an electrical connector of the type described having a construction characterized by its simplicity, inexpensiveness and ease of fabrication and assembly, facilitating its manufacture by mass production methods and making its cost competitive with conventional connectors currently employed for the same purposes.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the product possessing the features, properties and the relation of components which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

FIGURE 1 is a perspective view of an electric lamp incorporating, as its base, an electrical connector embodying the invention;

FIG. 2 is a partial perspective View, similar to FIG- URE 1, illustrating another embodiment of the connector;

FIG. 3 is a fragmentary sectional view of the lamp of FIGURE 1, the section being taken substantially in a plane through the center of the lamp;

FIG. 4 is an enlarged sectional view of the connector of FIG. 3 shown engaged in a conventional threaded lamp socket;

FIGS. 5, 6 and 7 are perspective views of different embodiments of a component of the connector;

FIGS. 8 and 9 are sectional views similar to FIG. 3 il lustrat-ing different embodiments of the electrical connector;

FIGS. 10 and 11 are sectional views taken along the lines 10-10 and 1111, respectively, of FIGS. 8 and 9;

FIG. 12 is a partially exploded and sectioned perspective view of a fuse embodying the electrical connector of the invention;

FIG. 13 is a view similar to FIGS. 5, 6 and 7, illustrating still another embodiment of the invention;

FIG. 14 is a partially exploded and sectioned perspective view of another embodiment of a lamp base;

FIG. 15 is a view, similar to FIG. 3, showing details of the lamp base of FIG. 14; and

FIGS. 16 and 17 are sectional views, similar to FIG. 3, illustrating additional embodiments of a lamp base constructed according to the invention.

The present invention resides in the design and construction of an electrical connector in the form of a lamp base, fuse, plug, or the like, for use in standard threaded electric lamp holders, and dilfering from standard threaded connectors, such as lamp bases, in that it is introduced into and withdrawn from the threaded socket without rotation. The advantages of such an electrical connector, particularly as a lamp base or fuse, have been enumerated in the aforementioned application and include safety and convenience both in installation and removal. The instant invention teaches the construction of a connector of the type described by which it is possible to predictably control the force required to with-' draw the connector [e.g., a lamp base] from a threaded lamp socket. It is possible to design the connector in such a way that the force required to introduce the connector into a socket remains insignificant While the force required for withdrawal may range from an equally insignificant quantity to a force such that withdrawal without rotation is a virtual impossibility. In other words, without changing the introductory force required, it is possible to design the connector so that it must be unscrewed from the socket or so that it barely remains in the socket and can be withdrawn with little or no effort.

It has been recognized that, in spite of its numerous and obvious advantages, the electrical connector of the invention, if it is to find acceptance, must be economically competitive with conventional threaded lamp bases. The structure of the electrical connector is obviously more complex than that of standard screw shells making the achievement of the economically competitive structure described herein significant in itself, since it represents a novel and unobvious structure characterized by simplicity, ease of fabrication and assembly, and ideally suited to manufactureof inexepnsive materials by mass production methods.

Reference is now made to FIGS. 1, 3 and 5 of the drawings wherein there is illustrated a lamp incorporating the electrical connector of the invention. The lamp comprises a conventional glass envelope 10 and a base 12 joined to the lamp envelope. Base 12 comprises three components, i.e., a shell 14, a retaining element 16 and a contact 18. The shell is designed to fit into the threaded socket while the retaining element engages the threads to retain the base within the socket and makes one of the electrical contacts and conatct 18 provides the other electrical connection for the lamp.

Shell 14 is generally cup shaped, symmetrical about an axis or center line, is open at one end and includes a peripheral wall 20 flared at the open end to engage and fit the tapered base portion of lamp envelope 10, and including a generally cylindrical section designed to fit within the minor diameter of a threaded lamp socket; and an end wall designated 22. End wall 22 includes an inwardly projecting tubular support member 24 having an axial bore, and is formed with an axial recess 26 in its outer surface communicating with the bore of the support member. Shell 14 is designed to be formed of organic plastic materials, such as the phenolics, by conventional molding methods; and peripheral wall 20 and support member 24 may taper slightly in thickness from the end wall toward the open end of the shell to facilitate removal from the mold in which the shell is formed. Formation of the shell from other moldable dielectric materials such as glass and ceramics in a possibility although shell designs more suited to such materials are shown and described hereinafter. The lamp envelope is secured within the base shell by a suitable cement or adhesive with the draw-off tube 28, common to most conventional lamps, extending into the bore of support member 24.

Retaining element 16, which performs the functions of retaining the lamp in a socket and providing an electrical connection, takes the form of a spider having a base or body 30 and a plurality of legs 32 extending radially from the body and symmetrically arranged with respect to an axis through the center line or axis of the lamp base. The retaining element is shown in FIGURE 1 as having four legs while another and equally preferred form of retaining element shown in FIG. 2, for example, has only two oppositely extending legs. Body 30, in the form shown in FIGS. 1, 3, 4 and 5, is generally circular, is formed with an axial hole 34, is engaged around support member 24, and disposed against the inner surface of end wall 22. Each of legs 32 includes three sections, these being a first section 36 extending from body 30 outwardly and toward the open end of the shell, a second or intermediate section 38 also extending outwardly and toward the open end of the shell, and a third or end section 40 extending inwardly and away from end wall 22. The second and third sections of each leg comprise, and are joined at, a bent portion which engages the threads of the lamp socket making an electrical connection and retaining the lamp in the socket. Retaining element 16 is formed of a resilient, conductive material, specifically sheet metal, and is adapted to fabrication by conventional metal forming methods with a minimum of operations to be performed.

Shell 14 is provided with a plurality of axial slots 42, one for each of legs 32, formed in peripheral wall 20 and extending from end wall 22 toward the open end of the shell. Each of legs 32 extends from the shell radially through a slot and thence (radially) back into the shell with the bent portion formed by the second and third sections disposed exterior of the shell. Each of slots 42 has a width approximately equal to the width of a leg 32 and a length sufficient to permit limited axial movement of the leg engaged therein. In the form shown in FIG. 4, the retaining element is loosely engaged in the shell and is free to move therein, being retained with the shell by virtue of the engagement of legs 32 within slots 42. Introduction of the retaining element into the shell is a relatively simple matter since the legs are deformable, and the movable mounting of the element 16 helps to insure engagement of all of the legs with threads of the socket as the element is free to position itself. In an alternative embodiment, the retaining element may be fixedly secured within the shell, e. g., by forcing body 30 toward end wall 22 in surrounding engagement with support member 24. In such an embodiment, the lengths of legs 32 may be varied so that the positions of the bent portions with respect to the end wall on base 36 of the retaining element correspond to the varying position of portions of a thread. In other words, the bent portions of the four legs, in succession around element 16, are spaced from the base 30 by increments of A of the thread pitch. In an embodiment having two legs, one bent portion of one leg would be spaced from the base by an added amount equal to /2 the thread pitch so that both legs engage portions of the same thread 180 apart.

Introduction of the connector into a standard threaded socket, designated 48 in FIG. 4, requires only the relatively little force needed to deform legs 32 inwardly and overcome any friction between the legs and the threaded socket. However, the force required to withdraw the connector can be varied from very little, i.e., equal to the introductory force, to a force which, if applied, would result in structural failure of the lamp assembly, and which necessitates rotation of the connector to achieve its removal from a threaded socket. Of course, the desired force lies between these two extremes and is determined by the configuration of the legs, particularly the directions in which the legs extend into engagement with the socket threads. The bent portion of each leg at the juncture of second and

third sections

38 and 40 is shaped to conform to the root and inner face of a socket thread as shown in FIG. 4 and to be tangent to the thread profile at a point, designated 44, on the inner face of the thread where the curvature of the thread profile changes from a concave to a convex curve. This bent portion of each leg may also be provided with a spherical dimple 46, as shown in FIG. 5, to better conform to the thread profile.

The forces tending to resist withdrawal of the retaining element from a socket are directed through point 44 in a direction normal to the thread profile at that point. In order for withdrawal to be accomplished, each leg 32 must be deformed inwardly about the point at the end of first section 36 at which the leg joins the body of retaining element 16. The force resisting withdrawal and hence, tending to bend or deform the leg, can be resolved into two components, one acting along a line between point 44 and the end of first section 36; and a second component tending to deform leg 32 inwardly about the end of first section 36. The magnitude of this lastmentioned deforming force is, of course, a function of the angle, designated on, subtended by a line tangent to the thread profile at point 44 and a line from point 44 through a point at the end of first section 36 where the latter joins base 30 of the retaining element. In order for the connector to be withdrawn, angle or should be less than since at angles of 90 or greater, there is no force component tending to bend the leg inwardly, and this component becomes greater as angle or is decreased, thereby reducing the force required for withdrawal.

The force required for withdrawal is, of course, dependent to a lesser extent on the stiffness and resilience of the material comprising the retaining element and the friction between the legs and the socket. However, these factors are a minor consideration in comparison to angle on in determining the force required for withdrawal. Although each of legs 32 may be substantially straight, they are illustrated as being bent in order to accommodate the thread profile and insure engagement of the leg only at the inner face of a thread at end section 40 and the bend of said section and intermediate section 38. Any tendency of the leg to bend at the juncture of first and

second sections

36 and 38 can be compensated for by forming the leg of a more rigid material so that the precise configuration of the leg remains a minor consideration in comparison to angle a which remains the major factor in determining the force required for withdrawal; and which in itself, determines the angle between the first and second sections of the leg. Angle a can be varied from a value of 90 (or greater), at which the resultant force tending to bend the leg is directed along a line through point 44 and the base end of the leg, or outwardly, making withdrawal, without rotation, a virtual impossibility; to approximately 40 at which the withdrawal force is very slight and is largely dependent on the resilience of the leg and hence is a function of the force required to overcome the outward spring force exerted by the leg. A preferred angle a for the legs of a retaining element having desirable retention characteristics and illustrated in FIG. 4, is approximately 75, and the force required for withdrawal is affected only slightly by the stiffness of the material comprising the retaining element.

Retaining element 16, as previously noted, functions as one electrical contact and one of the pigtails or leads, designated 50, of the lamp is joined to the retaining elernent either at the body or at one of the legs. In the form shown in FIGS. 3, 4 and 5, this electrical connection is achieved by lancing a leg, as shown at 52, and inserting lead 50 through the lanced portion of the leg and, if desired, the outer end of lead 50 extending through the lanced portion of the leg may be soldered to the outer surface thereof. Another suggested method is soldering, either to the body or to a leg.

The other electrical contact 18 is in the form of a conical spring formed of metal ribbon and engaged in recess 26. The other pigtail or lead 54 of the lamp extends through the bore of support member 24 into recess 26 where the lead is connected, for example, by soldering, to contact 18. Contact 18, comprising an axially compressible spring, insures good contact with the outer contact, designated 56, of the threaded lamp socket.

A number of different forms of retaining element 16, designed for use with shell 14 are conceivable and include an element formed from wire as shown in FIG. 6. The body of the wire retaining element comprises an intermediate section of a length of wire formed into a loop 58 while the end sections 60 of the wire comprise the legs, and are formed in accordance with the same considerations as apply to legs formed of sheet metal. Loop 58 is designed to encircle support member 24 while end sections 60 extend into engagement with the threaded socket to make an electrical contact and retain the connector in the socket.

In alternative embodiments of the connector shown in FIGS. 2, and 8 through 11, the retaining element is mounted on the exterior of the end wall of the shell. The shell, in the form shown in FIGS. 2, 8 and 10, and designated 62, is basically the same as shell 14 previously described, and differs therefrom by the provision on the outside of end wall 64 of a cylindrical support member 66 surrounding recess 68 in which a conical contact spring 70 is engaged. The retaining element, designated 72 (shown in FIG. 7) includes a circular body 74 having a center opening 76 engaged around support member 66 and is secured to end wall 64 by eyelets 78 extending through the end wall. Retaining element 72 includes a pair of legs 80, fabricated according to the invenion and extending within and from axial slots 82 formed in the peripheral wall 84 of shell 62. One of the leads 86 of the lamp is threaded through one of eyelets 78 where lead 86 is soldered to make an electrical connection between the lamp and element 72. In order to lessen the cost of the shell by reducing the material, e.g., organic plastic; to facilitate access, during assembly, to the interior of the shell; and to provide for ventilation and hence, cooler operation, end wall 64 is formed with a plurality of openings 88.

Another and somewhat similar embodiment of the connector is shown in FIGS. 9 and 11 as comprising a shell 90 having a flared peripheral wall 92 for holding the lamp envelope, and an end section 94 which may be described as a relatively thick end wall. End section 94 includes an axial bore 96 communicating with an axial recess 98 in which contact spring 70 is engaged, and an annular lip 100 on the outer end surface of section 94 surrounding recess 98. The ring-like body 74 of a retaining element 72 is secured in surrounding engagement with lip 100 to end section 94 by elongated eyelets 78. The legs 80 of the retaining element extend within and from axial recesses 102 in end section 94. Shell 90 is designed to be formed by molding and especially lends itself to fabrication of glass and ceramics as well as organic plastic material. In order to conserve materials, provide for access and promote air circulation within the connector, end member 94 is formed with a pair of openings 104, shaped so that the shell is, in effect, a tube open at both ends and having a bridge extending from side to side for supporting the retaining element and contact spring. Electrical connections with the lamp are made by way of leads extending through one of the eyelets to retaining element 72 and through bore 96 and recess 98 to contact spring 70.

The electrical connector of the invention is shown in FIG. 12 as embodied in a fuse comprising a generally cup-shaped upper section 106 having an end wall 108 and a skirt 110; and a base section 112 including an end por tion 114 and a support member 116 which, in the assembled position of the fuse, extends within upper, section 106. The fuse body is designed to be formed of glass or organic plastic materials or a combination of both, i.e., upper section 106 of glass and base section 112 of organic plastic, by conventional molding methods. End portion 114 of base section 112 is provided on its outer end with a recess (not shown) in which is engaged a conical spring contact 118 and support member 116 is provided with a central bore 120 communicating with the aforementioned recess and in which is mounted a conducting element 122 electrically coupled with spring contact 118. The fuse includes a retaining element 124 shown in detail in FIG. 13 and comprising a base 126 having an opening 128 corresponding in size and shape to the cross section of support member 116 and adapted to be engaged around the support member. Retaining element 124 includes a pair of legs 130 constructed in accordance with the considerations previously described. The cross-sectional configuration of support member 116, base 126 and opening 128 is approximately rectangular with the ends rounded rather than straight lines, corresponding to the generally circular configuration of fuses and fuse sockets. The base 126 of retaining element 124 is engaged in a recess in the upper surface of end portion 114. The fuse includes a fusable link 132 connected at one end to conducting element 122 and at its other end to a second conducting element 134, which extends parallel to the axis of the fuse outside of support member 116 and includes an end section located in contact with base 126 of retaining element 124. Fusable link 132 and conducting

elements

122 and 134 may comprise a single generally U-shaped strip of metal with the fusable link suitably formed to provide the requisite current carrying capacity. The inner wall of skirt 110 is shaped to conform to the outer surface of support member 116, so that the skirt retains second conducting element 134 and retaining element 124 in the position shown by engaging the second conducting element located in a recess in support member 116 between the support member and the skirt and engaging retaining element 124 between end portion 114 and the edge of the skirt. The skirt is provided with axial recesses 136 in its outer surface for accommodating legs 130 in the manner described heretofore, and upper section 106 and base section 112 are preferably secured together in the assembled condition by a suitable adhesive, although a force fit may prove satisfactory.

The electrical connector of the invention, designed as a lamp base, may comprise a body or shell formed of two parts rather than a single part. Such a construction shown in FIGS. 14 and 15 is particularly adapted to fabrication from glass as well as organic plastic material or a combination of both materials. This lamp base shell, designated 138, comprises an upper section 140 preferably formed of glass and a base section 142 which may also be formed of glass or, if desired, any dielectric material including ceramics and organic plastics. The upper section includes a generally circular wall 144 with an upwardly extending flared skirt 146 which engages the lamp envelope and downwardly extending inner and outer

cylindrical skirts

148 and 150 respectively. Wall 144 is provided with a central opening 152 communicatingwith the bore of inner skirt 148 and peripheral openings 154 communicating with the annular region between the inner and outer skirts. The outer skirt is provided with a pair of axial slots 156 for accommodating the legs 158 of a retaining element 160 including a base 162 and fabricated as shown in FIG. 5, as previously described.

Base section 142 of shell 138 comprises a base portion including an upper surface formed with a cylindrical support member 166 including a bore 168 communicating with a recess 169 in the lower or end surface of base portion 164 in which is engaged a conical contact spring 170.

Base portion 164 is also provided with a circular lip 712 which is engaged within outer skirt 150, and base 162 of retaining element 160 is engaged around support member 166 between the latter and circular lip 172 with legs 158 extending between the inner and outer skirts and outwardly through slots 156 in the outer skirt. One of the leads from the lamp envelope may be soldered to the base of the retaining element prior to assembly of the base section of the shell into the upper section of the shell and the two sections of the shell are thereafter retained together by a suitable cement or adhesive, the epoxy compounds being suggested for this purpose. Similarly, the two sections of the fuses shown in FIG. 12 may be retained together by a cement or adhesive as well as by friction between the inner surface of skirt 110 and the outer surface of support member 116 and second conducting element 134.

FIGS. 16 and 17 illustrate two-part lamp bases each including a cup-shaped shell formed of metal rather than a dielectric and a base formed of a dielectric such as organic plastics, ceramics, glass or the like. The lamp base shown in FIG. 16 comprises a cup-shaped shell 174 having a peripheral wall with an upper flared section 176 for engaging the base of the lamp envelope and a lower cylindrical section 178 having axial slots 180 for accommodating the legs 182 of a retaining element 184. Shell 174 can be formed by conventional metal drawing methods and includes a generally circular end wall 186 having a central opening 188. The lamp base includes an end section 190 comprising a generally cylindrical support tube 192 extending through opening 188 into shell 174 and a circular flange 194 secured to the outer end surface of end wall 186. End section 190 is formed of a dielectric material and the bore of tube 192 is divided by an internal flange 196 into inner and outer sections, the outer section accommodating a contact spring 198. Retaining element 18-4 includes a circular base 200 engaged around support tube 192 on the inside of shell 174 and both base 200 and flange 194 are secured to opposite sides of end wall 186 by rivets or eyelets 202, One of the leads or pigtails 204 of the lamp is connected to shell 174 in the usual manner by being threaded between flared section 178 into the lamp envelope from the shell and soldered to the flared section of the shell adjacent its edge. In an alternative embodiment, lead 204 may be threaded through one of eyelets 202 and soldered to the outer end of the eyelet. End section 190 mounts the other contact element 198 of the lamp base electrically insulating the two electrical contacts from one another.

The lamp base shown in FIG. 17 is basically the same as that of FIG. 16 and dilfers thereform in that shell 206 is formed with recesses 208 in its cylindrical section 210, rather than with slots as previously described, for accommodating the legs 212 of a retaining element 214. The lamp base of FIG. 17 includes an end section 216 similar to end section 190 previously described, and differing therefrom by virtue of the provision of an annular recess 218 in the upper surface of flange 220 surrounding support tube 222 for accommodating the base 224 of retaining element 214. Base 224 of the retaining element is provided with a pair of holes and flange 220 is formed with projections 226 which extend through the openings in the base and through similar openings in end wall 228 of shell 206 and are peened over or otherwise flattened at their ends, for retaining shell 206, retaining element 214 and end section 216 together. It is suggested that end section 216 be formed of a thermosetting organic plastic material which is only partially cured and in a thermoplastic state prior to assembly of the shell and end section. This condition of the end section permits projections 226 to be flattened by the application of heat, and curing of the end section can be completed after assembly of the lamp base, and may, in fact, occur simultaneously with the curing of the cement employed to adhere the'shell to the lamp envelope.

The connectors of FIGS. 16 and 17 have been illus-- trated as comprising separate shells and retaining elements each formed of sheet metal. However, in a modified embodiment (not shown), the shell and retaining element may comprise a unitary, integral structure with the end wall of the shell acting as the base of the retaining element and the legs thereof formed from portions of the cylindrical section of the shell.

While the connector of the invention is especially designed to be employed in conventional threaded (Edison base) lamp sockets and fuse holders, the inventive principles on which the design is based are equally applicable to connectors intended for use in other types of sockets, specifically, sockets provided with an internal ridge or shoulder having an inwardly inclined face similar in profile to the profile of a lamp socket thread. The basic consideration remains, specifically, the angle designated on, subtended by a line tangent to the thread face at a point thereon through which the retaining force is directed and another line extending from this point on the thread face through the point at which the leg of the retaining element joins the body of the retaining element. When this angle at is appreciably less than the connector can be withdrawn without rotation, and as the angle approaches 90, the force required for withdrawal increases so that at angles of approximately 90 or greater, the connector must be unscrewed from a threaded socket and withdrawal is otherwise impossible without actually breaking the connector or device of which it is a component. The connector is relatively simple and inexpensive in its construction, is easy to assemble, can be introduced into and withdrawn from sockets rapidly and conveniently, and is dependable in its function, effectively resisting unintentional dislodgement due, for example, to vibration.

Since certain changes may be made in the above product without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An electrical connector for direct axial insertion into and withdrawal from an internally threaded socket having a thread form composed of two circular segments tangent to each other, said connector comprising, in combination:

a body shaped to be introduced axially into said socket;

and

a resilient, electrically conductive retaining member having a base and at least a pair of legs extending freely and without support radially from points on opposite sides of said base;

said base being mounted on said body with each of said legs extending from one of said points on said base radially beyond the periphery of said base in a direction opposite to the direction of insertion into said socket;

each of said legs including a first section having an end shaped to present a surface for engaging a thread of said socket at a point on the'inwardly inclined face of said thread at which the profile of said thread face changes from concave to convex;

each of said legs being pivotable with respect to said base about said point on said base and being so formed that when said connector is engaged within said socket, a predetermined angle subtended by a first line extending from said point on said thread face radially outward and tangent to said thread face at said point thereon and a second line from said point on said thread face to said point on said base, is less than 90, the force required to withdraw said connector being proportional to said angle.

2. The electrical connector of claim 1 in which each of said legs is so formed that said predetermined angle ranges from 65 to 80 degrees.

3. The electrical connector of claim 1 in which said first section of each of said legs is bent inwardly intermediate said end thereof and said base.

4. The electrical connector of claim 1 in which said first section of each of said legs is substantially linear so that one component of the force exerted by said leg in resisting withdrawal is directed through said leg from said end to said point on said base.

5. The electrical connector of claim 1 in which said body is constructed to engage the threads of said socket at the minor diameter thereof and said retaining member is mounted on said body for limited omnidirectional movement with respect to said body sufficiently to permit each of said legs to position themselves in engagement with said thread.

6. The electrical connector of claim 1 in which said retaining member is formed of a length of wire including end sections comprising said legs and an intermediate section in the form of a loop comprising said base.

7. The electrical connector of claim 1 in which said body is formed of an electrically conductive material and 10 is shaped to fit within said socket in contact with said threads.

8. The electrical connector of claim 1 in which said body includes an axis substantially coincident with the axis of said socket and the direction of insertion and withdrawal; a resilient electrically conductive contact element is provided extending from the end of said body at said axis for making an electrical contact, said retaining member is electrically insulated from said contact element.

9. The electrical connector of claim 8 in which said body is electrically conductive and said electrical contact is electrically insulated from said body.

10. The electrical connector of claim 8 in which said ends of said first sections of said legs are located at different axial distances from said base.

References Cited by the Examiner UNITED STATES PATENTS 897,805 9/08 Wegner 339-73 1,317,548 9/19 Casper 33972 1,484,360 2/24 Polzien 33972 1,510,247 9/24 Smith 339-72 1,551,756 9/25 Laskowski a- 33972 1,628,636 5/27 Dominick 33972 1,647,355 11/27 Hendry 339-67 1,700,495 1/29 Hayward 33972 1,761,344 6/30 Huber 33972 2,071,769 2/37 Schlicker et a1. 339199 2,869,097 1/59 Stuart 33999 X 3,056,941 10/62 Eriksson 339-72 JOSEPH D. SEERS, Primary Examiner.

Claims

1. AN ELECTRICAL CONNECTOR FOR DIRECT AXIAL INSERTION INTO AND WITHDRAWAL FROM AN INTERNALLY THREADED SOCKET HAVING A THREAD FORM COMPOSED OF TWO CIRCULAR SEGMENTS TANGENT TO EACH OTHER, SAID CONNECTOR COMRPISING, IN COMBINATION: A BODY SHAPED TO BE INTRODUCED AXIALLY INTO SAID SOCKET; AND A RESILIENT, ELECTRICALLY CONDUCTIVE RETAINING MEMBER HAVING A BASE AND AT LEAST A PAIR OF LEGS EXTENDING FREELY AND WITHOUT SUPPORT RADIALLY FROM POINTS ON OPPOSITE SIDES OF SAID BASE; SAID BASE BEING MOUNTED ON AID BODY WITH EACH OF SAID LEGS EXTENDING FROM ONE OF SAID POINTS ON SAID BASE RADIALLY BEYOND THE PERIPHERY OF SAID BADE IN A DIRECTION OPPOSITE TO THE DIRECTION OF INSERTION INTO SAID SOCKET; EACH OF SAID LEGS INCLUDING A FIRST SECTION HAVING AN END SHAPED TO PRESENT A SURFACE FOR ENGAGING A THREAD OF SAID SOCKET AT A POINT ON THE INWARDLY INCLINED FACE OF SAID THREAD AT WHICH THE PROFILE OF SAID THREAD FACE CHANGES FROM CONCAVE TO CONVEX; EACH OF SAID LEGS BEING PIVOTABLE WITH RESPECT TO SAID BASE ABOUT SAID POINT ON SAID BASE AND BEING SO FORMED THAT WHEN SAID CONNECTOR IS ENGAGED WITHIN SAID SOCKET, A PREDETERMINED ANGLE SUBSTENDED BY A FIRST LINE EXTENDING FROM SAID POINT ON SAID THREAD FACE RADIALLY OUTWARD AND TANGENT TO AID THREAD FACE AT SAID POINT THEREON AND A SECOND LINE FROM SAID POINT ON SAID THREAD FACE TO SAID POINT ON SAID BASE, IS LESS THAN 90*, THE FORCE REQUIRED TO WITHDRAW SAID CONECTOR BEING PROPORTIONAL TO SAID ANGLE.