US3599169A

US3599169A - Lamp lock means

Info

Publication number: US3599169A
Application number: US805589A
Authority: US
Inventors: Lewis Detch
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-03-10
Filing date: 1969-03-10
Publication date: 1971-08-10
Anticipated expiration: 1988-08-10

Abstract

Locking means for incandescent lamps, particularly those having screw-threaded bases for assembly insertion in complementally screw-threaded lamp sockets, and serving to tightly seat the lamps in such sockets to the end that vibration, shock, heating and other possible service conditions will not cause the lamps to become loose, or ''''freeze,'''' in the sockets, thus ensuring long life to the lamps, establishment of continuous good electrical contact between the lamp bases and sockets, guarding against escape of the lamps from the sockets with possible injury to persons in their vicinity, particularly when the lamps are installed in overhead locations, and generally serving to provide for improved lamp operation. The locking means comprise a substantially circular, yieldable or resilient insert device for installation in that portion of the socket adjacent to the inner termination of the screw threads thereof with a snap action so that it will normally be retained therein, and provided with an axially substantially centrally located, radially inwardly extending circumferential flange the free edges of which are preferably chamfered for cooperation with the usual frustoconical end of the lamp base, and with axially offstanding, preferably outwardly tapered, circumferential outer lip portions for seating engagement with the inner surface of the lamp socket; the said circumferential flange being provided with radially inwardly extending, outwardly opening groove means serving to enhance the normal yieldability or resiliency of the device, such groove means serving, by choice, to contain a normally compressible plastic substance, or a resilient member, which will function to maintain the original characteristics of the device for continuous and repeated use. The formation of the device is such that it may effectively function no matter which of its axial faces is disposed outwardly of the socket, thus guarding against improper installation by relatively unskilled operatives. The device is preferably formed from a moldable plastic substance, such as nylon, which is capable of withstanding the operating temperatures of incandescent lamps, and when the aforesaid groove is filled with a normally compressible substance such substance may be a silicone adhesive, for example that known as ''''RTV.

Description

United States Patent Primary Examiner-Joseph H. McGlynn Alwrneywilliam H. Finckel, Jr.

ABSTRACT: Locking means for incandescent lamps, particularly those having screw-threaded bases forassembly insertion n complementally screw-threaded lamp sockets, and serving to tightly seat the lamps in such sockets to the end that vibration, shock, heating and other possible service conditions will not cause the lamps to become loose, or freeze," in the sockets, thus ensuring long life to the lamps, establishment of continuous good electrical contact between the lamp bases and sockets, guarding against escape of the lamps from the sockets with possible injury to persons in their vicinity, particularly when the lamps are installed in overhead locations, and generally serving to provide for improved lamp operationv The locking means comprise a substantially circular, yieldable or resilient insert device for installation in that portion of the socket adjacent to the inner tennination of the screw threads thereof with a snap action so that it will normally be retained therein, and provided with an axially substantially centrally located, radially inwardly extending circumferential flange the free edges of which are preferably chamfered for cooperation with the usual frustoconical end ofthe lamp base, and with axially offstanding, preferably outwardly tapered, circumferential outer lip portions for seating engagement with the inner surface of the lamp socket; the said circumferential flange being provided with radially inwardly extending, outwardly opening groove means serving to enhance the normal yieldability or resiliency of the device, such groove means serving, by choice, to contain a normally compressible plastic substance, or a resilient member, which will function to maintain the original characteristics of the device for continuous and repeated use. The formation of the device is such that it may effectively function no matter which of its axial faces is disposed outwardly of the socket, thus guarding against improper installation by relatively unskilled operatives. The device is preferably formed from a moldable plastic substance, such as nylon, which is capable of withstanding the operating temperatures of incandescent lamps, and when the aforesaid groove is filled with a normally compressible substance such substance may be a silicone adhesive, for example that known as RTV.

Tiff:

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LAMP LOCK MEANS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to means for ensuring the proper service operation of incandescent lamps of the screw-base type, and to this end their desired mechanical and electrical-contact retention in complementally screw-threaded sockets. The locking device may serve, also, to properly retain plug fuses in the sockets of their cutouts with good electrical contact and guarded against loosening and possible loss during service.

2. Description of the Prior Art The prior art now known is best represented by the U.S. Pat. of Gerhard Wieckmann, No. 3,101,984, granted Aug. 27, 1963, but this patent does not disclose a concept essentially analogous to that of the present invention for the reason that whereas the present invention is directed to a locking device which is susceptible of installation in unaltered screwthreaded lamp sockets of known, conventional types, that of the Wieckmann patent requires the employment of an especially designed, unconventional type ofsocket.

SUMMARY OF THE INVENTION This invention provides, primarily, a locking device for incandescent electric lamps of the screw-base type for insuring their proper mechanical and electrical contact retention in complementally screw-threaded lamp sockets, and comprises a yieldable or resilient member insertable in the inner end of the socket and engageable with the inserted end of the lamp base, when such base is screwed home in the socket, to frictionally secure the lamp base in the socket against vibration, shock and other service factors that might tend to loosen the lamp and possibly cause loss thereof from the socket or ineffective electrical contact between the complementary parts of the lamp base and socket.

OBJECTS OF THE INVENTION One object of the invention is to provide a simple, inexpensive and practical locking device primarily for screw-base electric lamps which will enable lamp users to obtain the maximum life of the lamps and their complemental sockets.

Another object is to provide a locking device which is selfcentering with respect to the lamp socket and lamp base and which, when the lamp base is properly seated in the socket, will maintain proper electrical contact between the lamp base, the shell of the socket and the usual spring contact terminal of the socket.

A further object is to provide a locking device which may be assembled in the lamp socket, and seated at the inner end thereof, simply by inserting it into the outer end of the socket by hand, and preferably engaged with the end of the lamp base and then screwing in the lamp base so that as it progresses into the socket it will move the locking device ahead of it until it is properly seated.

Another object is to provide an inserting and removal tool wherewith the locking device may be held, inserted into the socket and seated therein, and which, preferably is provided, also with means whereby the locking device may be removed from the socket after removal of the lamp, this tool preferably being formed of insulating material, such as nylon, so that the insertion and removal of the locking device may be accomplished while the socket is live without danger of shock to the operative.

Still another object is to provide a locking device so dimensioned that when inserted into operative position within the socket it will be retained therein within the usual enlargement or cavity thereof at the inner end of the threaded portion of the socket shell, thus making possible replacement, or installation, of a lamp, no matter what the position of the socket may be, and particularly when it is in inverted position, without the likelihood of the device escaping from the socket.

Another object is provide a locking device which is of onepiece construction, lightweight and rugged, and which may be made in a variety of sizes for'accommodation to lamps and lamp sockets of various sizes, particularly those known as Standard and Mogul." Moreover, the device being formed of a nonconducting material such as nylon, it is virtually indestructible, is noncorrosive, and guards against wear of the lamp protected by it, and also against vibration, shock, jolts, and excessive temperatures to which the lamp and socket may be subjected.

A still further object is to provide, in combination with the locking device, a rubber, or synthetic rubber, sealing ring, such as an O-ring, disposed between the outer end of the outer shell of the socket and the adjacent bulge of the glass envelope of the lamp, the locking device and ring thus jointly used serving to prevent the entrance into the socket past the lamp of moisture, dirt, dust, grime, metal chips and the like.

Another object is to provide a locking device of the type disclosed which is'axially reversible, end for end, thus assuring its proper location in the lamp socket no matter which end is outwardly disposed, and thereby tending to counteract assembly mistakes by unskilled operatives.

A further object is to provide a device which, when disposed between the base of the socket shell and the lamp base, will serve to prevent freezing" (adhesion) of the lamp base and the socket shell when subjected to overheating, galvanic corrosive action and other not unusual causes, thus serving to prolong the operative life of lamps and prevent burnouts, destruction of lamp bases, and fpu'llout of socket shells, with the accompanying interruption of services and the necessity for relamping. These features are of particular importance in the now prevalent use oflamp sockets and lamp bases made of aluminum, a metal which tends to readily support corrosive action.

Other objects and advantages of the invention will become apparent as set forth in the following description.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing illustrating the invention, in the several figures of which like parts are similarly designated,

FIG. 1 is an axial face view of the lamp lock device of the invention,

FIG. 2 is a perspective view of the device shown in FIG. 1,

FIG. 3 is an axial sectional elevation of the device taken on the line 3-3 of FIG. 1, a

FIG. 4 is a view similar to that of FIG. 3, but showing a filling of a compressible and yieldable, or relatively elastic, plastic substance in the circumferential groove, which substance tends to enhance the resiliency of the device in an axial direction,

FIG. 5 is an axial face view of the lamp lock device in a form preferably so modified as to accommodate it to use with Mogul" (relatively large) lamps and sockets,

FIG. 6 is a perspective view of the device as shown in FIG.

FIG. 7 is an axial sectional view, with parts in elevation, of the device as shown in FIG. 5, and taken on the line 7-7 of FIG. 5,

FIG. 8 is an axial sectional elevation of the device as shown in FIG. 5, taken on the line 8-8 of FIG. 5, but including a filling of a compressible, and relatively resilient, yieldable plastic substance in the circumferential groove of the device,

FIG. 9 is a transverse sectional elevation of the lamp lock device of the style shown generaily in FIGS. 1, 2 and 3, but showing a spring ring disposed within the confines of the circumferential groove,

FIG. 10 is an axial sectional eievation taken on the line 10-10 of FIG. 9.

FIG. 11 is a view similar to H6. 9 but showing a modified form of spring ring disposed within the circumferential groove,

FIG. 12 is a view similar to FIG. 9., but showing a further modified form of spring ring disposed within the circumferential groove,

FIGS. 13 and 14 are side elevational views of the lamp lock device showing two optional forms of scarification of its circumferential surfaces, thus serving to afford passages for the escape of heat generated in the vicinity of the device.

FIG. 15 is a sectional elevation of a lamp assembled in a conventional socket with the lamp lock device of the invention disposed therein, the lamp base being shown as not fully seated solidly enough to cause the lamp lock device to fully function.

FIG. 16 is a fragmentary sectional elevation showing an assembly of parts similar to that shown in FIG. 15 but greatly enlarged and with the lamp base seated against the lamp lock device solidly enough to cause it to fully function,

FIG. 17 is a side elevation of a preferred form of tool for effecting insertion and removal of the lamp lock device of the invention into and from a lamp socket,

FIG. 18 is an edge elevation of the tool of FIG. 17,

FIG. 19 is a top plan view ofsuch tool, and

FIG. 20 is a bottom elevation of such tool.

DESCRIPTION OF THE EMBODIMENTS SHOWN Having reference particularly to FIGS. 1 to 4, it will be seen that the lamp lock device of the invention has a circular body 1, preferably formed from a suitable plastic, moldable material, such, per choice, as Nylon because of its relative permanence, its elasticity, resiliency and yieldability, its insulating properties, its ability to withstand relatively high temperatures without undue distortion, and its inherent lubricity; the said member having a cylindrical sidewall 2, an axially medially disposed radially inwardly extending circumferential flange 3 the free edges which are preferably chamfered, a pair of similar circumferential outer lip portions circumferentially coincident with the sidewall 2 and axially offstanding from said flange and preferably outwardly tapered to provide relatively thin terminal edges, a radial slit or slot 6 standard-type inwardly through the sidewall 2 and terminating within the flange 3.

As Standard-type from the form and general proportions of the locking device as shown in FIGS. 1 to 4 and 9 to 14, which is adapted for use with 61 lamps and sockets, the form and general proportions of the locking device shown in FIGS. 5 to 8 will adapt the device for use with Mogul-type lamps and sockets. In this latter form the locking device has a relatively wide radialslit or slot 6' and its lip portions 5 in areas opposite the slit or slot 6 are cut away, as shown at 8, down to the surface of the circumferential flange 3', the slit or slot 6 and the cutaway areas 8 of the lip portions 5 thus being adapted to straddle, or avoid interference with, the usual raised or offstanding portions at the base of the socket members of Mogul sockets.

As shown at 9 in FIG. 4, the circumferential recess 7 may be filled with a normally compressible, and preferably somewhat yieldable or resilient substance such as a silicone adhesive commercially known as RTV, whereby the locking device is given additional resiliency to ensure its restoration to initial form after having been subjected to pressure during the seating of the lamp base in the lamp socket. The circumferential recess 7' of the form of locking device shown in FIGS. 5 to 8 may be similarly treated, as shown at 9', FIG. 8.

As shown in FIGS. 9 to 12, the circumferential recess 7 may contain a split ring which will serve not only to limit possible undue axial distortion of the locking device under pressure but will also serve to restore the device to its desired circular form after the application of such pressure is released and to limit its circular expansion under such pressure. In FIG. 9 the ring 10 is shown as circular, but it may be of the form 11 shown in FIG. 11 wherein an offstanding, or noncircular, portion 12 extends past the circumference of the locking device and is adapted to frictionally contact the adjacent cylindrical surface of the lamp socket shell in order to prevent possible rotation of the locking device within the socket shell. Alternatively, the spring ring may be of other noncircular forms, such as the serpentine form of ring 13 of FIG. 12. Similar, but more sturdy split spring rings may be employed with the locking devices for Mogul lamps and sockets shown in FIGS. 5 to 8.

The split spring rings preferably made a noncorrosive nickel-steel wire of a diameter to furnish adequate stiffness and to provide approximately a 0.0045-inch clearance between its exterior surface and the adjacent walls of the recess 7 which, in the form of locking device shown in FIGS. 1 to 4 and 9 to 14, adapted for use with the so-called Standard lamps and lamp sockets, are spaced apart approximately onesixteenth (0.0625-inch). Obviously, the spring rings for Mogul lamps and sockets will be made from wire of greater diameter, due to the greater spacing of the walls of the recess 7', but the spacing of the exterior surface of the wire ring will be proportionately similar.

As shown in FIGS. 13 and 14, the outer surfaces of the sidewalls 2 of the lamp lock device may be scarified to provide relatively tortuous passages for the escape of heated air or gas from the inner end portion of the lamp socket shell. In FIG. 13 this scarification is in the form of knurling l4, and in FIG. 14 the scarification is shown in the form of milling 14' with the recesses of the milling in one portion of the sidewall out of axial alignment with the recesses of the other portion in order to provide the desired tortuous passages. In this connection it will be realized that when a filling is used in the circumferential recess 7, FIG. 4, or 7', FIG. 8, such filling, being a flowable plastic at the time of its application, will generally terminate outwardly in a concave meniscus, as indicated at 15 in FIGS. 4 and 8, thus providing against blocking, under ordinary conditions of use, of thechannels formed by scariflcation, or the scariflcation may be effected after application of the plastic filler. Similar scarification may be employed in lamp lock devices of the form shown in FIGS. 5 to 8, if desired.

Having reference to FIGS. 15 and 16, wherein a complete assembly of lamp and lamp socket, with interposed lamp lock device is shown, it will be seen that the lamp socket 16 has the usual inner shell 17 the outer portion of which is provided with the customary screw thread 18 terminating inwardly in an enlarged cavity I9 and secured to the insulating base 20 by screws 21 and rivets 22 as is customary, and the outer metal sheath or shell, comprising the outer portion 23 and removable cap 24, is separated from the inner screw-threaded shell 17 by an insulating sleeve 25.

As shown in FIG. 15, in which the lamp 26 is not fully seated in the lamp socket, it will be seen that the lamp lock device 1 is disposed in the enlarged cavity 19 of the inner shell 17 by insertion thereinto through the outer end of such shell, but is not sufficiently compressed by the inward screwing of the inner end of the lamp base 27 to radially expand the lamp lock device into intimate contact with the wall of the inner shell at such cavity or to cause intimate contact of the screw threads of the lamp base with those of the said inner shell. However, in FIG. 16 the lamp base 27 is shown as screwed home in the socket and thus, through cooperation of the inner frustoconical end 28 of the lamp base with the circumferential inner edges 4 of the flange 3, causing the lamp lock device to expand at the radial slit or slot 6 and seat firmly and inescapably in the enlarged cavity I9. Also, this final seating of the lamp base 27 will afford intimate, and proper electrical, contact between the threads of the lamp base and those of the inner shell 17 of the lamp socket I6, and proper electrical contact, also, between the terminal 29 of the lamp base and the spring contact member 30 of the lamp socket 16.

As shown in FIGS. 15 and I6, and as hereinbefore mentioned, a rubber or other sealing ring 31 may be interposed between the bulge 32 of the glass envelope of the lamp and the outer end 33 of the outer metal sheath or shell portion 23 of the lamp socket to effectively seal the lamp socket against entrance of moisture, dust, grit, metal chips and other foreign substances.

Obviously, when the lamp lock device 1 has been inserted into, and positioned within, the enlarged cavity 19 of the screw-threaded inner shell 17 of the lamp socket 16, it cannot escape therefrom for the reason that its external diameter is slightly greater than the inner diameter of the screw threads of such inner shell.

Although the lamp lock device may be seated in the enlarged cavity 19 of the screw-threaded inner shell 17 of the lamp socket 16 by preliminary insertion of the device into the outer end of the threaded portion of such shell and then forced into the enlarged cavity by screwing the lamp base into the shell to carry the device ahead of it into the enlarged cavity, or held against the frustoconical end 28 of the lamp base 27 with the fingers and thus forced into the cavity 19 of the shell by screwing in of the lamp base, l have found that its insertion into and removal from such cavity may be measurably facilitated, without the hazard of shock to the installer, particularly in its removal from a live socket, by the provision of an appropriate tool such as that illustrated in FIGS. 17 to 20. This tool, which is preferably made of a dielectric material, such as nylon, comprises a body portion having a central longitudinal slot 34 to provide two relatively resilient arms 35, each of said arms being provided at its free end with a pair of spaced lip means 36 and 37 extending outwardly from its edges. The lip means 36 at the outer ends of the arms being capable, when the arms are squeezed together, of passing through the circumferential inner opening of the flange 3 of the lock device, and the lips 37, which are spaced from the lip means 36 a distance to approximately loosely span the axial thickness of the flange 3, being offset sufficiently from the edges of the arms to bear against the adjacent face of the said flange. Thus, when it is desired to insert a lock device into a socket shell it is merely necessary to compress the arms together sufficiently to enter the lip means 36 past the flange and then release the arms so that the lip means 37 will lie adjacent to the face of the flange opposite that contiguous to the lip means 36. Thus, the lock device will be held at the end of the tool forinsertion into the socket shell by pressure exerted upon it by the lip means 37. This will make possible desired insertion of the lock device into position in the enlarged cavity 19 of the shell no matter what the location and position of the socket may be. I

At its other end the body portion of the tool is provided with rigid ear means 38 which have a combined overall length approximately equal to, or slightly less than, the diameter of the circumferential opening in the flange 3. Either one of these ear means may be inserted to a position with its inner face against the inner face of the flange 3 to grip thereagainst and make possible, by an outward pull, the removal of the lock device from its seated position in the enlarged cavity 19 of the socket shell 17. This tool is of particular value in removing lock devices from live sockets, it having been found that when an operative attempts to remove the lock device from such a socket by using his bare fingers he is very apt to receive a surprising and possibly injurious shock due to contact of his fingers with, and bridging of, live portions of the socket. A simple hook member, not shown, may be substituted for the ear means 38 of the tool just described.

It is to be noted that, when the lock device is used, the engagement of the lamp base with it as the lamp is screwed home in the socket will, due to the chamfered edges of the inner circumference of the flange 3, cause the lock device to spread at the radial slit or slot 6, as hereinbefore mentioned, so that it will firmly engage the wall of the enlarged cavity 19 of the lamp socket shell 17 and will, at the same time, serve to anchor the socket and lamp base due to the resiliency inherent in the nature of the lock device, thereby to counteract any tendency of the lamp to become unscrewed or unseated, particularly in the presence of vibration and shock. This is of primary importance in installations in which the sockets are in inverted position.

Also, the circumferential lip portion which bears upon the inner wall, or bottom of the socket shelf 17, will retain the circumferential flange in spaced relation to the screwheads or rivets which anchor the shell to the insulating base of the lamp socket.

Furthermore, with the use of the lock device, over insertion of the lamp in the socket is prevented, thus guarding against crushing of the spring contact element in the base of the socket. Moreover, the resiliency of the lock device makes it unlikely that an operative will screw the lamp into the socket with such pressure as to break the envelope of the lamp from the lamp base.

Various changes and modifications are considered to be within the principle of the invention and the scope of the following claims.

I claim:

1. Lamp lock means, comprising a one-piece yieldable member for optional free insertion in and removal from the socket for an incandescent lamp and between the inner extremity of said socket and the inner extremity of the base of said lamp, said lock means being of generally cylindrical ring form and by virtue of its yieldable nature being capable of radial expansion upon exertion of axial pressure upon it by the lamp base to furnish frictional engagement between its outer peripheral wall and the interior of the wall of said socket, and having an axially medial radially inwardly extending circumferential flange for frictional engagement with the inner extremity of the lamp base, to thus frictionally insure retention of the lamp in operative engagement with the socket in the presence of shock, vibration and other extraneous forces tending to unseat the lamp. t

2. Lamp lock means as defined in claim 1, in which said yieldable member is provided with aradial slot extending through its peripheral wall and through said flange, whereby said member is capable of distortion to accommodate it to circumferential expansion and contraction.

3. Lamp lock means as defined in claim 1, in which the inner circumferential edges of said flange are chamfered for proper engagement with a frustoconical lamp base terminal. 4. Lamp lock means as defined in claim 1, in which substantially cylindrical outer surfaces of the yieldable member are provided with a plurality of relatively circumferentially spaced scarifications extending throughout the axial extent of such surfaces and serving to void gases generated within the lamp socket in the zone of location of the yieldable member.

5. Lamp lock means as defined in claim 1, in which the said flange is provided with an outwardly opening circumferential groove serving to enhance the axial yieldability of the yieldable member.

6. Lamp lock means as defined in claim 5, in which the said groove is filled with means tending to conteract undue distortion of the yieldable member in the presence of axially applied pressure.

7. Lamp lock means as defined in claim 6, in which the distortion counteracting means is a resilient ring member of a dimension axially of the groove serving to substantially fill said groove.

8. Lamp lock means as defined in claim 6, in which the distortion counteracting means is a resilient yieldable material.

9. Lamp lock means as defined in claim 8, in which the resilient yieldable material is a plastic substance.

10. Lamp lock means as defined in claim 1, in which the outer peripheral wall includes circumferential lip means axially offstanding from the two axial faces of said flange, the yieldable member being thus provided with two similar axial termini and thereby being made reversible end for end so that either of said lip means may be engaged with the inner extremity of the socket shell.

11. Lamp lock means as defined in claim 10, in which said lip means are axially outwardly tapered so that when the yieldable member is positioned in a lamp socket they will avoid contact with the rivets and the like which serve to affix the socket shell to its carrying base means.

Patent No. 3,599,169 Dated August 10, 1971 Inventor( ewis Detch It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 1, before "provide" insert to Column 3, line 32, after "edges" insert 4 of

lines

36 and 37, cancel "standard type"; line 37, before "inwardly" insert extending through said side wall 2, lip portions 5 and flange 3,

and a circumferential recess 7 extending radially line 39, cancel "As Standardtype" and insert As distinguished line 41, cancel "61" and insert "Standard" type Signed and sealed this 25th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents RM Po-1050 (10-69) USCOMM-DC GOEWIS-F'Bi U75 GOVERNMENT PRINTING OFFICE I96! 0-3G638l,

Claims

1. Lamp lock means, comprising a one-piece yieldable member for optional free insertion in and removal from the socket for an incandescent lamp and between the inner extremity of said socket and the inner extremity of the base of said lamp, said lock means being of generally cylindrical ring form and by virtue of its yieldable nature being capable of radial expansion upon exertion of axial pressure upon it by the lamp base to furnish frictional engagement between its outer peripheral wall and the interior of the wall of said socket, and having an axially medial radially inwardly extending circumferential flange for frictional engagement with the inner extremity of the lamp base, to thus frictionally insure retention of the lamp in operative engagement with the socket in the presence of shock, vibration and other extraneous forces tending to unseat the lamp.

2. Lamp lock means as defined in claim 1, in which said yieldable member is provided with a radial slot extending through its peripheral wall and through said flange, whereby said member is capable of distortion to accommodate it to circumferential expansion and contraction.

3. Lamp lock means as defined in claim 1, in which the inner circumferential edges of said flange are chamfered for proper engagement with a frustoconical lamp base terminal.

4. Lamp lock means as defined in claim 1, in which substantially cylindrical outer surfaces of the yieldable member are provided with a plurality of relatively circumferentially spaced scarifications extending throughout the axial extent of such surfaces and serving to void gases generated within the lamp socket in the zone of location of the yieldable member.