US3676835A

US3676835A - Electrical connector

Info

Publication number: US3676835A
Application number: US135553A
Authority: US
Inventors: James A Holly
Original assignee: Hollymatic Corp
Current assignee: Hollymatic Corp
Priority date: 1971-02-01
Filing date: 1971-04-20
Publication date: 1972-07-11
Anticipated expiration: 1989-07-11
Also published as: AU3648471A; DE2164031A1; CH532848A; NL7117165A; FR2124999A5; IT952010B; ES399394A1; BE778646A; GB1313985A; CA937308A

Abstract

An electric current carrying device such as an electric light bulb releasably receivable in a socket in which the device comprises a mounting base with an electrically conducting peripheral wall which may be of metal, an inner electrically conducting wall which may also be of metal in the socket for receiving the base in electrical contact, a helical screw thread on either the base or the socket wall and a plurality of circumferentially spaced spring tabs on the other wall. Each tab has a plurality of ridges spaced from each other in a direction parallel to the axis of the base or socket with each ridge lying along a section of a helix of substantially the same pitch and dimensions as those of the screw thread for engaging in the screw thread and retaining the base in the socket in its innermost position. The spring tabs are elongated and each has one edge that is parallel to the axis fixed to its wall as by being integral therewith and an opposite edge free in a cantilever construction and spaced from its wall with the result that when the base is inserted in the socket the tabs are compressed toward their wall to exert a holding spring action serving to retain the base in the socket and the helical section ridges on the tabs engage the screw thread at a plurality of circumferentially spaced areas not only to securely retain the base in the socket but also to provide good electrical contact between the walls and, as in the case of a light bulb, between the end contact members on the base and socket.

Description

United States. Patent Holly 51 July 11, 1972 [54] ELECTRICAL CONNECTOR James A. Holly, Richton Park, Ill.

[73] Assignee: Hollymatic Corporation, Park Forest, Ill.

[22] Filed: April 20, 1971 [21] Appl. No.: 135,553

Related US. Application Data [63] Continuation-in-part of Ser. No. 111,571, Feb. 1,

1971, abandoned.

[72] Inventor:

Primary Examiner-Marvin A. Champion Assistant Examiner-Lawrence J. Staab ArromeyHofgren, Wegner, Allen, Stellman & McCord ABSTRACT An electric current carrying device such as an electric light bulb releasably receivable in a socket in which the device comprises a mounting base with an electrically conducting peripheral wall which may be of metal, an inner electrically conducting wall which may also be of metal in the socket for receiving the base in electrical contact, a helical screw thread on either the base or the socket wall and a plurality of circumferentially spaced spring tabs on the other wall. Each tab has a plurality of ridges spaced from each other in a direction parallel to the axis of the base or socket with each ridge lying along a section of a helix of substantially the same pitch and dimensions as those of the screw thread for engaging in the screw thread and retaining the base in the socket in its innermost position. The spring tabs are elongated and each has one edge that is parallel to the axis fixed to its wall as by being integral therewith and an opposite edge free in a cantilever construction and spaced from its wall with the result that when the base is inserted in the socket the tabs are compressed toward their wall to exert a holding spring action serving to retain the base in the socket and the helical section ridges on the tabs engage the screw thread at a plurality of circumferentially spaced areas not only to securely retain the base in the socket but also to provide good electrical contact between the walls and, as in the case of a light bulb, between the end contact members on the base and socket.

1 1 Claims, 1 1 Drawing Figures Patented July 11, 1972 2 Sheets-Sheet 1 FIGI ///////'/fi4 FIGG INVENTOR.

JAMES A. HOLLY BY J WLM.

ATTORNEYS.

ELECTRICAL CONNECTOR CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my co-pending application, Ser. No. 111,571, filed Feb. 1, 1971, and now abandoned.

BACKGROUND OF TEE INVENTION This invention is in the field of electric current carrying devices such as electric light bulbs which are customarily screw threaded and that are screwed into a similarly screw threaded socket to secure the device in the socket and to make and maintain good electrical contact with elements in the socket so that an electric current can flow from the socket into and through the device. This invention is concerned with a spring structure either on the device or on the socket that not only maintains the engagement of the device in the socket but also insures that good electrical Contact will be had at all times. As a result of this invention the electric current carrying device such as the light bulb is quickly insertable into a receiving socket and removable therefrom when desired and either the socket or the base can be the customary screw thread type otherwise known as the Edison thread socket or base.

There have been many attempts to provide quickly insertable and releasable electric current carrying devices such as light bulbs having spring elements on either the bulb base or the receiving socket that would permit rapid insertion and withdrawal and provide good electrical Contact. All of these of which applicant is aware have been unsatisfactory for various reasons. Among these inherent defects in the prior art devices are the following. Many of the bases do not make adequate retaining and electrical contact upon insertion of the base in the socket but require rotational adjustment of a substantial degree to insure this retention and contact. Others of the prior patented devices do not retain the base in the socket securely as the retaining elements are so weak that they are easily displaced so that often the weight of the device itself will either break the electrical Contact or will actually release the device such as the bulb. A similar disadvantage is that many of the devices are held by the spring retaining means only on one side so that in practice the device is held at an angle rather than coaxially with resulting instability and poor electrical contact. Attempts have been made to correct these defects, but these prior patented structures have been expensive and often unreliable.

The most pertinent prior patents of which applicant is aware are U.S. Pat. Nos. 1,104,577; 1,174,378; 1,258,646; 1,551,756; 1,721,365; 1,761,344; 1,898,498; 2,004,550; 2,118,503; 2,308,016; 2,372,266; 2,722,668; 2,786,189; 2,835,878; 2,869,097; 3,056,941; 3,215,972 and 3,478,300.

SUMMARY OF THE INVENTION One of the features of this invention is to provide an electric current carrying device releasably receivable in a socket and having a mounting base such as a light bulb base with either the base or the socket having a helical groove extending around it and a plurality of sets of a plurality of spring tabs each positioned around the other wall and with each tab having a ridge arcuately arranged with respect to the axis of the base or the socket and a tab in each set engaging the groove to secure the base in the socket.

Other features and advantages of the invention will be apparent from the following description of certain embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary axial sectional view through an electrical screw threaded socket.

FIG. 2 is a fragmentary side elevational view of an electric lamp base having retaining spring tabs embodying the invention.

FIG. 3 is an end elevational view of the embodiment of FIG. 2.

FIG. 4 is a view similar to FIG. 1 but illustrating another embodiment of the invention.

FIG. 5 is a transverse sectional view taken substantially along line 5-5 of FIG. 4.

FIG. 6 is an enlarged end elevational view of a spring tab viewed substantially from line 66 of FIG. 3.

FIG. 7 is an end elevational view similar to FIG. 3 but illustrating the embodiment that includes ten of the retaining spring tabs rather than the eight shown in FIG. 3.

FIG. 8 is a projected elevational view of a peripheral wall which may be of either the base or the socket and containing two symmetrically arranged sets of five spring tabs each.

FIG. 9 is a view similar to FIG. 8 but illustrating the embodiment where each set contains four spring tabs.

FIGS. 10 and 11 are views similar to FIGS. 8 and 9 but illustrating further embodiments of the arrangement of the spring tabs in a peripheral wall.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a standard Edison type electrical socket 10 having an insulating body 11 within which is located a generally cylindrical sheet metal wall 12 having a standard Edison screw thread 13 as substantially universally used on electric lamp sockets and bases especially in this country. Such an Edison thread has seven threads per inch with a pitch of 0.142 inch and the threads and separating grooves 14 are curved to a radius. In such an Edison socket and base the diametrically opposite areas of the screw thread are spaced apart in a direction parallel to the axis 15, herein referred to as the axial spacing, of one-half the pitch or 0.071 inch.

The socket 10 having its wall 12 of electrically conducting material such as metal makes electrical contact with the bulb that is received in the socket. The other spaced Contact is a metal contact member 16 at the bottom of the socket and with both the wall 12 and contact 16 being provided with customary electrical leads l7 and 18, respectively.

FIGS. 2 and 3 illustrate an embodiment of the invention wherein the generally cylindrical base 19 of a light bulb 20 is insertable into the socket 10 to be retained therein securely and with good electrical contact. This base 19 is provided with the customary end electrical Contact 21 for making electrical engagement with the contact 16 of the socket when the base 19 (shown enlarged) is inserted to its innermost position within the wall 12 of the socket. As shown in FIGS. 2 and 3 the base 19 of this embodiment is provided with a plurality of circumferentially spaced spring tabs 22 each having a plurality of ridges 23 separated by grooves 24 similar to the ridges and grooves of a continuous screw thread as illustrated by the socket of FIG. 1.

As shown, these ridges 23 are spaced from each other in an axial direction or parallel to the base axis 43. The angled ridges 23 and grooves 24 as stated are each a section of a helix of substantially the same pitch and dimensions as the screw thread of the socket. Each spring tab 22 has one edge 25 that is parallel to the axis 43 fixed to the base wall 26 and with the opposite end 27 free and spaced from its wall as shown most clearly in FIG. 3 in a cantilever construction. The free end 27 of each tab is spaced from the wall as shown so that the tab is free to function as a cantilevered spring and upon insertion of the base 19 into the socket 10 the spring tabs are compressed toward their wall 26 to exert a spring retaining action and also to make good electrical contact with the socket wall 12.

As shown in the expanded elevational view of FIG. 8 the tabs 22 are arranged in a plurality of circumferentially spaced sets, here shown as two, each containing a plurality of tabs. As an aid in indicating the two sets FIG. 8 has thereon a broken line 27 dividing the two

sets

28 and 29 so as to indicate most clearly their relationship.

The spring tabs in one wall that engage the groove of the thread in the other wall to retain the electric current carrying device in the socket are in a plurality of sets of a plurality of spring tabs each symmetrically spaced around the wall that contains the tabs, with corresponding tabs on all the sets having corresponding ridges circumferentially and axially spaced apart distances equivalent to the circumferential and axial spacing of those portions of the continuous screw thread groove that are engaged by the ridges when the base is securely received in the socket in intimate retaining and electrical contact. Thus, where the preferred two sets of tabs are used, corresponding ridges on corresponding tabs in the two sets are spaced circumferentially 180 and axially one-half pitch, as illustrated in FIG. 8, when the screw thread groove is an Edison standard thread because in the standard Edison thread diametrically opposite corresponding portions of the helix of the thread are axially spaced apart one-half pitch.

In the preferred embodiments, as illustrated, of two sets of symmetrically spaced tabs corresponding tabs 22 in each set and adjacent tabs in each set as illustrated by the first tabs 30, second tabs 31 and so forth to the fifth or last tabs in the FIG. 8 embodiment are axially spaced apart one-half pitch and circumferentially spaced apart 180 as these are the corresponding spacings on the Edison standard thread. If, of course, more than two sets of tabs were used the circumferential and axial spacing would be correspondingly different because the areas engaged by the corresponding tabs in the more than two sets would be less than l80 apart.

This axial and circumferential spacing of the corresponding ridges on corresponding tabs in the two sets is maintained whether each set contains an odd number of tabs such as the five in FIG. 8 or an even number such as the four in FIG. 9. In both instances of odd and even numbers of tabs in each set adjacent tabs are spaced one-half pitch apart for an Edison thread and corresponding tabs in the two sets are axially spaced apart one-half pitch also and circumferentially 180.

The axial spacing of one-half pitch in adjacent tabs of each set as illustrated by the broken horizontal lines of FIG. 8 has been found by experience to provide a construction that produces secure mechanical and electrical contact and one in which the spring tabs adjust themselves automatically to the helix of the receiving groove to obtain this secure engagement. Thus with the construction of this invention it is very simple to insert the device into the socket with a straight axial force, to maintain secure engagement as long as desired, and to remove it by a similar reverse axial force.

FIGS. 2 and 3 illustrate the embodiment where the projecting spring retaining tabs 22 are on the electrical device base 19. FIGS. 4 and 5 illustrate the embodiment wherein the spring tabs 34 are part of the metallic wall 35 of the socket 36. Whether on the socket or the base the structure and operation of the spring retaining tabs is the same and is as described.

In the embodiment of FIG. there are disclosed two sets 46 and 47 of spring tabs 22 in which corresponding tabs in each set are circumferentially aligned. Thus the first tab 48 of the first set 46 is aligned with the first tab 49 of the second set 47. Similarly, successive tabs 50 and 51 are horizontally aligned. With this arrangement wherein corresponding tabs in all sets are circumferentially aligned the first tab 48, for example, in the first set 46 will engage the screw thread while the corresponding first tab 49 in the second set 47 will not engage the opposite sides of the screw thread but will engage the crest of the thread because, as was pointed out, in the standard Edison screw thread diametrically opposite sides of the thread are axially spaced one-half pitch apart as illustrated in FIG. 8. However, the two tabs 51 and 52 on opposite sides of the corresponding tab 49 will make engagement with the screw thread because they are approximately one-half pitch off from the first tab 48. This then will give, in effect, a three point engagement of the tabs 48, 52 and 51, for example, on the opposite sides of the screw thread which will result in a stable connection with good mechanical and electrical engagement.

The tabs 48, 49, 51 and 52 have been selected only by way of example as it is obvious that if the engaged tab on one side of the screw thread were the tab 50 then the two on opposite sides of the corresponding tab 51 in the other set would be tabs 49 and 53. In any event, the stable three point engagement would be maintained in all positions of the base relative r ila to the socket so long as the base were inserted into the socket to its greatest extent and with the socket and base axes 15 and 43, respectively, coinciding. The embodiment illustrated by FIG. 10, therefore, is preferred.

FIG. 11 illustrates the embodiment where the spring tabs 37 in the metal wall 38 either of the socket or the base are arranged in two

sets

39 and 40 with the sets being symmetrically arranged in the wall 38 as shown. In this embodiment of FIG. 11 each tab 37 contains the plurality of ridges 42 which in each instance are a total of three, as in the earlier embodiments, except that in the embodiment of FIG. 11 corresponding ridges 42 of each set are aligned in

parallel helices

41 and 41 having the same pitch and transverse dimensions as the screw thread into which the member containing the wall 38 is received. The parallel nature of the ridges 42 is illustrated in FIG. 11 by the parallel equally spaced alignment lines 41. As is illustrated there the central alignment line 41 is a continuation of the top line 41 while the bottom line 41 is a continuation of the middle line 41, both in the two sets.

The primary function of the spring tabs is to provide secure mechanical and electrical engagement by the spaced tab ridges snugly engaging portions of the thread, as described. However, even those intermediate tabs that are not snugly received in the screw thread groove also aid in the retaining action merely by the springiness of the tabs. Thus, assuming that on one insertion of the tabs into a socket the second tabs in each set are securely and snugly received in the helical groove as illustrated at 14 the intermediate tabs between these will contribute to a secure holding action merely by the springiness of these tabs pressing against the receiving wall.

Having described my invention as related to the embodiments shown in the accompanying drawings, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the appended claims.

I claim:

I. An electric current carrying device releasably receivable in a socket, comprising: a mounting base on said device having an outer electrically conducting peripheral wall and a longitudinal base axis; an inner electrically conducting wall in said socket for receiving said base wall upon insertion of said base to an innermost position in the socket with both walls in electrical contact, the socket having a longitudinal socket axis substantially coinciding with said base axis when said base is in said innermost position, one of said walls having a helical groove extending around it; and a plurality of sets of a plurality of spring tabs each positioned around the other said wall with each tab having a plurality of ridges accurately arranged and longitudinally spaced with respect to a said axis, a tab in each said set engaging said groove to secure said base in said socket, said spring tabs each having one edge parallel to a said axis fixed to its said wall and an opposite edge free and spaced from its said wall so as to be compressed back toward its said wall upon said insertion.

2. The device of claim 1 wherein individual tabs in all said sets have ridges circumferentially and axially spaced distances corresponding to the portions of said groove engaged by said individual tab ridges.

3. The device of claim 1 wherein the adjacent tabs in each said set have corresponding ridges axially spaced apart a distance substantially equal to the axial spacing of diametrically opposite areas of said groove.

4. An electric current carrying device releasably receivable in a socket, comprising: a mounting base on said device having an outer electrically conducting peripheral wall and a longitudinal base axis; an inner electrically conducting wall in said socket for receiving said base wall upon insertion of said base to an innermost position in the socket with both walls in electrical contact, the socket having a longitudinal socket axis substantially coinciding with said base axis when said base is in said innermost position, one of said walls having a helical groove extending around it; and a plurality of sets of a plurality of spring tabs each positioned around the other said wall with each tab having a plurality of ridges arcuately arranged and longitudinally spaced with respect to a said axis, a tab in each said set engaging said groove to secure said base in said socket, said spring tabs each having one edge parallel to a said axis fixed to its said wall and an opposite edge free and spaced from its said wall so as to be compressed back toward its said wall upon said insertion, wherein the adjacent tabs in each said set have corresponding ridges axially spaced apart a distance substantially equal to the axial spacing of diametrically opposite areas of said groove and wherein said corresponding ridges in corresponding tabs in all said sets are circumferentially aligned.

5. The device of claim 3 wherein said corresponding ridges in corresponding tabs in all said sets are circumferentially and axially spaced apart distances equivalent to the circumferential and axial spacing of those portions of the groove engaged by said ridges.

6. The device of claim 1 wherein there are two sets each of a plurality of said tabs with the sets being symmetrically located in their said wall.

7. The device of claim 6 wherein corresponding tabs in said sets are spaced about 180 apart.

8. The device of claim 7 wherein said corresponding tabs are circumferentially aligned.

9. The device of claim 8 wherein the adjacent tabs in each said set have corresponding ridges axially spaced apart a distance substantially equal to the axial spacing of diametrically opposite areas of said groove.

10. The device of claim 7 wherein said corresponding tabs have corresponding ridges in all said sets circumferentially and axially spaced distances corresponding to the portions of said groove engaged by said individual tab ridges.

11. The device of claim 4 wherein there are two sets each of a plurality of said tabs with the sets being symmetrically located in their said wall.

Claims

1. An electric current carrying device releasably receivable in a socket, comprising: a mounting base on said device having an outer electrically conducting peripheral wall and a longitudinal base axis; an inner electrically conducting wall in said socket for receiving said base wall upon insertion of said base to an innermost position in the socket with both walls in electrical contact, the socket having a longitudinal socket axis substantially coinciding with said base axis when said base is in said innermost position, one of said walls having a helical groove extending around it; and a plurality of sets of a plurality of spring tabs each positioned around the other said wall with each tab having a plurality of ridges accurately arranged and longitudinally spaced with respect to a said axis, a tab in each said set engaging said groove to secure said base in said socket, said spring tabs each having one edge parallel to a said axis fixed to its said wall and an opposite edge free and spaced from its said wall so as to be compressed back toward its said wall upon said insertion.

7. The device of claim 6 wherein corresponding tabs in said sets are spaced about 180* apart.