US2641662A

US2641662A - Combined switch and fastener

Info

Publication number: US2641662A
Application number: US227640A
Authority: US
Inventors: John W Liley
Original assignee: MICHAEL J BASSO
Current assignee: MICHAEL J BASSO
Priority date: 1951-05-22
Filing date: 1951-05-22
Publication date: 1953-06-09
Anticipated expiration: 1970-06-09

Description

June 9, 1953l J. w. I ILEY COMBINED SWITCH AND FASTENER ssheets-sheet 1 Filed May 22, 1951 mxo Jrz

VMMPWWI flll June 9, 1953 J. w. I ILEY COMBINED SWITCH AND FASTENER 3 Sheets-Sheet 2 Filed May 22, 1951 June 9, 1953 J. w. LILEY 2,641,662

COMBINED SWITCH AND FASTENER Filed May 22, 1951 v :5 sheets-sheet 3 IN V EN TOR.

Patented June 9, 1953 COMBINED SWITCH AND FASTENER John W. Liley, Ferndale, Mich., assignor of fiftyfve per cent to Michael J. Basso, Detroit, Mich.

Application May 22, 1951, Serial No. 227,640

(CI. 20G- 54) 27 Claims.

vThis invention relates to electrical switches, and more particularly to a, combined switch and fastener construction especially adapted for use in combination with the hinges of vehicle and other doors. This application is a continuationin-part of my applications Serial No. 121,624, filed October 15, 1949, and Serial No. 164,159, filed May 5, 1950.

In the past, switch constructions have been provided adapted to be actuated by the opening and closing of a closure means such as a door, for operating a lighting circuit or similar electrical circuit. In the conventional switch of this type, the switch unit must be mounted on the door frame by means of a separate opening in the frame, thus requiring the additional labor and expense of forming this opening, as well as the provision of fastener means for attaching the switch adjacent the opening.

, It is an object of the present invention to overcome the disadvantages of the conventional door switch construction, and to provide a door operated switch which eliminates the necessity of forming an eXtra opening in the door frame, but which can be installed in the assembly simultaneously with the attaching of the door hinges to the frame, without any additional labor being required.

It is a further object to provide a switch of the I above character, which is combined with a fastener used to attach the hinge to the door frame, so that the switch operates through the fastener opening, and requires no additional elements for securing the switch to the frame.

It is another object of the invention to provide an electrical switch of the above character, which is of the plunger type, and inwhichthe plunger is disposed' axially within .one of the hinge fasteners, whereby the fastener serves the `dual purpose of supporting the door hinge be pulled through the door frame fastener opening and the hinge fastener opening, and then attached tothe switch, the fastener thereafter being applied to the door frame in the usual man.- ner, without disturbing this connection.

.It is a further object, in several forms of my invention, to provide a switch of the above character, in which the fastener itself functions as one of the switch terminals, and in which the switch is capable of closing its contacts even though dirt or other foreign matter may be` present on the terminals.

It is also an object, in another form of the in extremely eflicient construction, and in which,

there are few moving parts to get out of order.

Other objects, features, and advantages of the present invention will become apparent from theA subsequent description, taken in conjunction with the accompanying drawings.

In the drawings:

Figure 1 is a side view, partly in cross-section, of a preferred form of the combined switch and fastener, wherein the fastener is utilized as one of the terminals of the switch;

Figure 2 is a side view, partly in cross-section, of the switch shown in Figure 1 installed in a, door frame and hinge, the switch being shown in.

its open position;

Figure 3 is a front view of the switch of Figures 1 and 2 showing the disposition of the plunger within the fastener;

Figure 4 is a side view, partly in cross-section, of a modified form of the improved switch, hav-4 ing theplunger spring enclosed within the unit;

Figure 5 isa fragmentary cross-sectional view.V

of another modification of the switch, utilizing a plunger ofnonconductive material;

Figure 6 is a side cross-sectional view of still another modication of the switch, for use with a two-wire circuit wherein two terminal sets are used;

Figure 7 is a cross-sectional view taken along the line 'l-l of Figure 6 and showing the guide means for the contacts;

Figure 8 is a fifth embodiment of the invention,

similar in principle to that of Figure 6, but having a modified terminal construction; and.

Figure 9 is a cross-sectional view taken along the line 9-9 of Figure 8 and showing the lateral configuration of the elements.

er used for attaching a door hinge to the door frame, so that the switch is operated by the opening and closing of the door. It will be understood however, that the principles of the invention are equally applicable to other types of fas- The invention is shown as applied to a fasten-K'` teners, where it is desired to have a switch operated by an element extending from one of the members secured by the fastener.

The invention comprises in general a fastener such as a screw or bolt which is of essentially standard construction, this fastener being combined with and forming a part of a plungertype switch. The plunger is disposed axially Within the fastener, the latter supporting the plunger for axial movement therein. Resilient means are provided for normally urging the plunger outwardly from the head of the fastener, this resilient means being yieldable to allow a fastening tool to be applied to the fastener when it is being assembled. The inner end of the-'plunger supports one or more switch terminals, these terminals being movable axially with the plunger, so that the switch is closed when the plunger extends from the fastener, and is open when the plunger is partially or fully depressed. In its simplest form, the invention contemplates the use of the inner end of the fastener as one of the switch terminals, although this need. not be the case. The mounting of the plunger within. the fastener, as well as the method of attaching the: switch terminals to the inner end ofthe plunger, is such that the fastener may be rotated into its fastening position without turning the switch terminals. or twisting the wires which are attached to such terminals. The method. of attaching the terminal or terminals to the inner end of. the plunger is preferably such that relative lateral movement or pivoting action is permitted between the. terminals, thus insuring closure of the switch despite dirt. or other foreign matter which may accumulate on the contacts.`

lReferring more particularly to the drawings, Figures 1-3 illustrate aY preferred embodiment of the invention in which the fastener, generally indicated at ll, is shown as. a Phillips head screw of the type used in attaching vehicle doors, refrigerator doors and the like to their respective door frames. The screw Il has a shank portion i2 -provided with an external thread I3, and a tapered head portion M having a socket l5 for receiving a Phillips head tool (not shown), and being adapted to engage a lock washer i6'. The screw il isessentially of standard manufacture, but is preferably provided with a chamfered or tapered surface Il at its inner end, and an axial bore i8.. The borey i8 extends axially from the socket l5, the inner end, of thebore being of smaller diameter and provided withY a radial` shoulder i! so that thev end. of the, shank has a bearing portion il! for supporting and guiding the switch plunger 22.

Plunger 22 is essentially of rod-like or cylindrical shape, and supports the. resilient spring 2,3, which is disposed aroundv its periphery and is utilized to normally urge the plunger outwardly fromthe. fastener head. Spring 23 engages at one end the shoulder i9 of the borev I8, and at its other end a head 2li which is formed at the outer end of the plunger 22- As is seen in Figure 1', the plunger may be of slightly tapered shape. so that a small clearance space 25 exists. between the plunger and the guide surface 2i when the plunger is extended. The material of which` the plunger is made is not critical, although it is preferably fabricated of metallic stock or other material having substantial strength and durability.

The inner end 0f the plunger 22 supports a tubular member generally indicated at 26, of'

conductive material, this tubular member vservtached.

ing as both a switch terminal and as connecting means for the insulated wire conductor 21 which leads from the battery (not shown) or other source of electrical power. For this purpose, a supporting member generally indicated at 28 is provided for securing member 26 to the inner end of the plunger, this supporting member being preferably fabricated of a plastic orA otherl non-conductive material such as nylon. The inner end of plunger 22 is provided with a reduced portion 29 having an annular gripping ring 3l integral therewith. The supporting member 28 is provided with a recess 32 extending axially therein, and the reduced portion 29 of the plunger is disposed within this recessso that theV supporting member 2g abuts the shoulder 33 between reduced portion 29 of the plunger and the main portion of this plunger. Since the gripping ring 3l preferably has a forced fit with the supporting member 23, the latter member is thus xedly secured to the inner end of the plunger.

The supporting member is provided with'an annular groove 35 which extends around its otherwise cylindrical surface, this groove having. outwardly flared side Walls 35. The tubular member 26 has a mounting and contact section 36 and a connector section 3l which is of somewhat smaller diameter than the section 36. When the switch is assembled, the section 36 is slipped axially over the supporting member 2B and is preferably secured thereto by pressing section 36 inwardly adjacent groove 35i, so that' a plurality of projections 38 are provided extending into this groove. It willbe observed that a slight clearance space 3d is provided between the projections 38 and the bottom and side walls of groove 34. It will thus be seen that relative rotation between the tubular member 2,6 and the supporting member 2.8 is permitted, and in particular that the tubular member may be held from rotating, for instance by the attached wire 2l, while the supporting member 28 rotates with the plunger and the fastener il while the fastener is being at- It will'be understood that other types of securing means could be provided between the tubular member 26. and the plunger 22 to allow relative rotation therebetween, without violating the principles of the invention.

When in its assembled position the tubular member 2.6 extends pastthe shoulder33 so that it is free to engage the tapered surface Il of the fastener Il. For this purpose, the tubular member is provided with a flared contact flange 4l engageable with an intermediate portion of thisv tapered` surface.

axial distance exists between the end 42 of the fastener and the end surface 43 of supporting member 28. The contacts il' and 4| are thus assured of positive engagement, since the compression. in spring 23 will urge the plunger 22constantly outwardly.

The bared end of conductor 21 is preferably attached to the connector section 31 of the tubular member by means of crimping section 31, as

shown for example at 44. It will be understood however that other methods of `attaching the conductor 2l to the tubular member coul'dbe used. It will beseen that when the conductor is secured to the tubular member, a. continuouselectrical path will exist from the conductor to thecontact surface M. It will also be noted that the conductor is completely insulated from the plunger 22 since the supporting member 28, which is of It vwill be observed that, when flange 4l engages surface il, a substantial non-conductive material, prevents any contact of these two elements. serve that due to the play 39 which exists between the tubular member and the supporting member, it is possible for the contact surface 4I to engage a portion of the contact surface I1, while dirt or other foreign matter prevents engagement of other portions of these surfaces. This is because the tubular element is allowed a pivoting action around the supporting member 28 without disengaging projections 38 and groove 34.

The application of the combined switch and fastener to a door hinge is shown in Figure 2. In this illustration, one leaf 45 of the hinge is shown as being secured to the door frame 46, the fastener II .being threadably engaged with an internallyr threaded member 41 such as a nut which is welded or otherwise secured to the inside of the frame. In assembling the switch and fastener in this manner, the wire 21 is first passed through the nut 41 and the openings in frame 46 and hinge leaf 45. rIhe bare end of the wire 21 is then crimped within the section 31 of tubular member 26. The hinge and frame holes are then aligned, and the wire and tubular member pushed back through these holes. It will be observed that the tubular member will pass freely through the nut 41, since its diameter is substantially less than that of thread I3. The threads of the screw I I are then engaged with nut 41, and the screw is driven to its full home position by means of a wrench or other tool.

It is a principle of the invention that the tool for driving the fastener may 'be applied Without interference from the switch portion of the device, and without disturbing the switch portion in any way. The operation of this principle will be obvious from the foregoing discussion, since it will be seen that when the tool is applied to socket I5, it will depress plunger 22 by contact with its head 24, compressing spring 23, so that the plunger will be retracted within bore I8 of the fastener. This position is shown in dot-dash lines in Figure 2, and it will be seen from this figure and from Figure 3 that the plunger is capable of full retraction so that the tool may fully enter the socket I5. When this action occurs, the contacts I1 and 4I will of course be separated. As the fastener is rotatably driven, friction between the fastener and plunger, especially through the intermediary of the spring 23, will cause rotation of the plunger as well as of supporting member 28. Since, as described previously, denite play 39 exists between the supporting member 28 and tubular member 26, the tubular member will not be forced to rotate with the supporting member.' This will prevent unwanted twisting of the wire 21 within thedoor frame. When the fastener has been driven fully home, removal of the tool will cause immediate projection of plunger 22, and the contacts I1 and 4I will thereafter be normally engaged. Since fastener II is grounded to the frame, a lighting or other circuit will be completed by the contact.

In operation, with the door (not shown) normally closed, the hinge leaf 48 attached to the door will engage the head 24 of the plunger, thus retracting the plunger and separating the contact surfaces I1 and 4I to open the electrical circuit. Upon opening of the door, the hinge leaf 48 will leave head 24, allowing spring 23 to project the plunger, closing the contact. The wire 21 will of course be supported so that it may move back and forth with the tubular member 26. It will be observed that all the switch parts are en- It is also important to obtrely enclosed within the door frame, thus preventing the accumulation of dirt or other foreign matter on the contact surfaces. Should dirt accumulate however on the contact surfaces, the pivoting action described previously will insure engagement of the contacts on at least a portion thereof. Relative radial movement between the contact surfaces I1 and 4I will also be permitted because of the clearance space 25 existing between the plunger 22 and the fastener I I. Should it be desired to repair or replace the switch, it is merely necessary to remove the screw II from the hinge and withdraw the switch through the apertures in the nut, frame and hinge. Since the ordinary hinge will be provided with a plurality of attaching screws, the replacement of the switch may thus Ibe effected without in any way disturbing the mounting of the door on the frame.

Figure 4 illustrates a second embodiment of the invention which is similar in principle to that of Figures 1-3, but wherein the plunger spring 49 is enclosed within a tubular member 5I of conductive material which is secured as an extension to the reduced end 52 of fastener 53. Inthis embodiment, the fastener is provided with an axial bore 54 extending entirely therethrough, this bore being of substantially the same diameter as the plunger 55, so that the plunger is slidably mounted therein. The tubular member 5I, which is in effect an extension of the fastener and which acts as a spring housing and as a contact for the switch, is provided with a plurality of inwardly extending tabs 56 which secure the end 51 of the spring 49 against axial movement. The opposite end 58 of the spring is of reduced diameter, and engages a reduced portion 59 of the plunger 55, the shoulder 6I on the plunger preventing movement of this end of the spring. The spring is preferably of the tension type so that the plunger will be normally urged outwardly from the head 62 of the fastener. The inner end of the plunger 55 is provided with a further reduced portion 63 to which is xedly secured a supporting member 64 of nonconductive material, similar to the supporting member 28 of the previous embodiment. Member 64 is preferably provided with oppositely disposed tapered surfaces 65 and 66, a cylindrical portion 61 extending from portion 65 against spring end 58.

The unit is provided with a combined wire connecting element and contact generally indicated at 68, which is analogous to tubular member 26 of the previous embodiment. This element comprises a wire connector section 69 within which the bare end of the wire 1I is inserted and secured, and a socket section 12 having a plurality of axially extending spring fingers 13 which grip the supporting member 64. These spring ngers have inwardly inclined portions 14 which may be initially forced over the flared surface 6G of the supporting member 64, and thereafter engage the flared surface 65 on the opposite side of this supporting member. The engagement of the spring fingers with supporting member 64 is preferably such that relative rotation between these parts is permitted, so that, as in the previous embodiment, the fastener may be driven home without twisting of the wire 1I. f

When the plunger 55 of the embodiment of Figure 4 is permitted to move into its extended position, the inwardly inclined portions 14 of the fingers 13 will engage the annular end surface 15 of tubular member 5I, thus completing a circuit between the wire 1I and the fastener 53. It will be observed that, as in the previous embodiment, the spring viingers 13 are completely insulated from the plungertlil, and thus from the fastener, except when the contacts are closed. Likewise, as in the previous embodiment, relative lateral movement will be permitted between the spring finger contacts and thesurface 15, by virtue of the play i6 existing between the spring fingers and the supporting member e9.

Figure shows a third embodiment of the invention which .is generally similar in principle to that of the previous embodiment but wherein the plunger 11 is fabricated of nonconductive material such as plastic, rather than of conductive material. A contact element 1e of conductive material is rotatably secured to the reduced end 19 of plunger 11. Spring 8i normally urges this contact element into engagement with the end 92 oftubular extension member 33, the angular contact surface 8d of element 18 insuring mutual contact of the elements. The wire 85 is secured within the connector portion S5 of contact member `153. It will. be observed that in this construction'the supporting member, such as member @il in Figure 4, is eliminated, since the nonconductive nature of the plunger 11 makes the supporting member unnecessary. Figures 6 to 9 illustrate two more modifications of the invention which are generally imilar in principle to the previous modifications, but Which are especially adapted for use in two-wire systems which do not use the grounded fastener as part of the circuit. In Figures 6 and 7 the fastener 81 is provided with an extension member S3 of annular shape which is rotatably secured to the reduced end 99 of the fastener by means of a snap ring 9|. This extension member is fabricated of insulative material and has embedded in its `walls a pair of

conductors

92 and 93 having Contact ends Si@ and 95 respectively projecting inwardly into the space 95 within the extension member. Space 9b is preferably of noncircular cross-section, and a contact nut 91 secured to the reduced end 93 of the plunger 99 'is slidably housed within this space. A compression spring |01 is held between contact nut 91 and a plug |92 at the end of extension 88, this spring normally urging the contact nut into engagement with contacts 94 and 9b. The opposite ends of

conductors

92 and 93 extend outwardly from extension 38 and are provided with male terminals |03 and Hill respectively, these terminals being adapted to be engaged by a receptacle l5 attached to the end of the two-wire cable Hit. The other end of plunger 99 may be provided with an enlarged head |91 movable within a counterbore |98 in the fastener 81. In assembling the unit shown in Figures 6 and '7, the spring ||l| and contact unit 91 will be placed within the tubular` housing 38, and this housing then mounted on the end of the fastener by means of snap ring 9 l The plunger may then be threadably engaged with contact nut 91, the rotation of the nut being prevented because of the noncircular shape of the nut. It will be observed that a driving rotation of fastener 81 will not cause twisting of wire cable i6, since the snap ring 9| permits relative rotation between the fastener and housing 88. In operation, spring lili will normally urge contact nut 91 into bridging engagement With contacts 9e and 95, plunger 99 being held in projected position, and depression of the plunger will move the contact nut to interrupt this bridging contact.

Figures 8 and 9 illustrate another embodiment of the two-wire type of switch similar in principle to that of Figures 6 and '7, but Which utilizes a metallic switch housing lili? in Place of the nonconductive housing E3 of the previous embodiment. The extension |99 is provided on its outer surface with a pair of oppositely disposed elongated recesses Hl and H2, within which are disposed conduotors i i3 and H4 respectively. These conductors are preferably insulated by dipping them in rubber or coating them with a plastic varnish or the like, and have inwardly extending contact ends ||5 and H6 which project through apertures lli' and H9 respectively in the extension |99. The contact ends H and H are adapted to be bridged by a U-shaped bridging member |9 embedded in a block |2i of insulated material. Block |2| is slidably disposed within housing |99 and is secured to the reduced end |22 of the plunger, in this case by a bayonet slot |23. The block is normally urged toward the contact ends H5 and Ht by spring |29, so that the ends of the bridging member engage the contact ends.

'A plug |25, heldin place by a pin |25, holds spring 24 within member 99. The outer end of condoctors H3 and lid; may be provided, as in the previous embodiment, with male terminals |21 and 28 respectively. A plastic or other insulating sleeve |29 may be positioned over housing |09 to further insulate the conductors and to protect the switch housing.

While it will be apparent that the preferred embodiments of the invention herein disclosed are Wellcalculated to fulfill the objects above stated, it lwill be appreciated that the invention is susceptible to modification, Variation and change without departing from the proper scope or fair ,l meaning of the subjoined claims.

What is claimed is:

l. In combination, a rotatably applied fastener having a shank portion, a plunger within said shank portion, the head of said plunger being movable between a position extending outwardly from said shank portion and a position retracted within said shankportion, an electrical contact movable by said'plunger during movement of the latter between its said positions, and a second electrical contact engageable by said first Contact during said movement, the two contacts being in engagement when the plunger is in one of its said positions and in spaced relation when the plunger is in its other position.

2. In combination, a fastener having a shank portion and a head portion, the head portion being adapted to be engaged by a tool for applying said fastener, a plunger within said fastener, the head of said plunger being movable between an extended position projecting outwardly of said head portion and a retracted position within said shank `portion and .out of obstructing relation with said tool, and electrical conductor connecting means carried by said plunger, said connecting means being rotatable with respect to the plunger.

3. In combination, a rotatably applied fastener. a plunger within said fastener, the head of said plunger being movable between a position extending from said fastener an-d a position retraoted within said fastener, electrical contact means .actuatable by saidv plunger during its movement between said positions, and electric conductor connecting means carried by said plunger, said connecting means being rotatable with respect to said plunger.

4. In combination, a. rotatable fastener, a plunger within said fastener, the head of said plunger being movable between a position projecting from said fastener and a position retracted within said fastener, electrical contact means actuatable by said plunger into closed position ywhen the plunger moves into its extended position, and resilient means urging the fastener into its extended position. Y

5. In combination, a rotatable fastener having a shank portion and a head portion adapted to be engaged by a rotating tool, a plunger within said fastener, the head of said plunger being movable between a position extending from said head portion and a portion retracted within said shank position, resilient means for urging said plunger toward its extended position, electrical contact means adapted to be actuated by said plunger, and electrical conductor connecting means carried by said plunger, said connecting means being rotatably mounted with respect to said plunger, whereby the fastener may be rotated Without rotating said connecting means.

6. In combination, a rotatably applied fastener, a plunger movable Within said fastener, an electrical contact movable by said plunger, and a second electrical Contact engageable by said first contact during said movement, said contacts being in engagement when the plunger is in one position and in spaced relation when the plunger is away from said position.

7. In combination, a rotatably applied fastener, an actuating element movable Within said fastener, an electrical contact actuatable by said element during its movement, said contact being engageable with said fastener when the element is in one position, and electrical conductor connecting means supported by said fastener, said connecting means being mounted for rotational movement with respect to the fastener.

8. In combination, a fastener, a plunger movable within said fastener, electrical contact means actuatable by said plunger during its movement, said Contact means being engageable with an end surface of said fastener in one position of the plunger, resilient means for urging the plunger into said position, and electrical conductor connecting means supported' by said plunger, said connecting means being mountedv for rotational movement with respect to said plunger.

9. In combination, a fastener, a plunger movable within said fastener', resilient means urging said plunger toward one end of said fastener, electrical contact means carried by said plunger and insulated therefrom, second electrical oontact means engageable with said first contact means when said plunger is moved toward said one end of the fastener, an-d electrical conductor connecting means connected to said first contact means, said connecting means being rotatable with respect to said plunger.

l0. In combination, a fastener, a plunger movable within said fastener, resilient means for urging said plunger toward one end of said fastener, an insulating member carried by one end of said plunger', electrical contact means rotatably mounted on said insulating member, second electrical contact means engageable by said first contact means when the plunger is moved toward said one end of the fastener, and electrical conductor connecting means connected to said rst contact means, whereby said connecting means is also rotatable with respect to said insulating member.

11. The combination according to claim 10, said first contact means being supported for limited pivotal movement with respect to said insulating member, whereby said rst and second contact means may be mutually engaged at only a portion of their respective surfaces.

12. In combination, a fastener, a plunger movable within said fastener, resilient ymeans for urging the plunger toward one en-d of the fastener, altubular member mounted on said plunger and having a contact portion conductively engageable with said fastener when the plunger is urged toward said one end of the fastener, an electrical conductor connecting portion on said tubular member, and means for supporting said .tubular member for rotational movement with respect to said plunger.

13. In combination, a fastener, a plunger movably mounted Within said fastener, resilient means disposed within said fastener and urging said plunger toward one end of the fastener, an insulating member secured to one end of the plunger, a tubular member supported for rotational and limited pivotal movement on said insulating member, and a contact portion on said tubular member and engageable with the other end of said fastener when the plunger is urged toward said one end of the fastener.

14. In combination, an externally threaded fastener, an axial bore within said fastener and having a shoulder therein, a plunger within said fastener, resilient means disposed within said bore andengageable With said shoulder and one end of the plunger to urge the plunger into a position projecting fromone end of said fastener, an insulating member secured to the other end of said plunger, an electrically conductive member rotatably mounted on said insulating Vmember and having a contact portion conductively engageable with the 'other end of said fastener when the plunger is insaid projected position, and electrical conductor connecting means on said conductive member.

15. The combination according to claim 14, said fastener being further provided with a toolreceiving recess, lsaid plunger being movable to a retracted position within ysaid axial bore by the application ofa tooltozsaid recess.

16. In combination, a fastener having an extension thereon, a plunger movable Within Said fastener, resilient means Within said extension for urging said plunger toward one end of said fastener, electrical contact means carried by said plunger and conductively engageable with said extension When the plunger is moved toward said one end of the fastener, and electrical conductor connecting means connected to said contact means.

17. In combination, a fastener having an extension thereon, a plunger movable Within said fastener, resilient means within said extension for urging the plunger toward one end of said fastener, an insulating member secured to one end of said plunger, and electrical contact means comprising a plurality of ngers mounted on said insulating member and engageable with said extension when the plunger is moved toward said one end of the fastener, said fingers being supported for rotational movement with respect to said insulating member.

18. In combination, a fastener having an eX- tension of conductive material, a plunger of insulative material movable Within said fastener, electrical contact means rotatably secured to one end of said plunger and engageable with said extension when the plunger is moved toward one end of said fastener, and means for connecting an electrical conductor to said contact means.

amnesia 1-9. In combination, a fastener having a hollow extension rotatably secured thereto, a pair of spaced electrical conductors supported by said extension and having contacts extending into the space within said extension, an actuating element movable within said fastener, an electrical bridging member within said extension and secured to one end of said element, and resilient means for urging said bridging member into engagement with said contacts.

20. In combination, a guide member having an extension rotatably mounted thereon, a pair of electrical conductors supported by said extension, a pair of contacts extending inwardly from said conductors, a yplunger movably mounted .in said guide member and having a portion extending within said extension, a contact bridging member movably disposed within said extension and secured to said plunger portion, said bridging member being of .non-circular shape whereby the bridging member is non-rotatably supported by said extension, and resilient means .for urging said bridging member rinto engagement with said contacts.

211. The combination according to claim 20, said extension being of insulative material, said conductors being embedded in spaced relation within said extension wall.

2-2. The combination according to claim 20, said extension having axially extending depressions along its peripheral surface, said conductors being disposed within said depressions, and radial apertures in said extension, the ends of said conductors extending through said apertures to Aform said contacts.

23. The combination according to claim 20, said conductors vextending beyond the end of said extension and being adapted to be connected to a two-Wire receptacle.

24. A device of `the character described comprising -in combination, an externally threaded member having a flared and recessed head and adapted to engage Aan opening in ra door hinge, a bore in saidY member, -a .plunger .longer than 12 said member and slidable in said bore, a switch housing mounted for rotation at one end of said threaded member, electric conductors carried by said housing and arranged to be contacted by a conductive nut carried at one end of said plunger.

25. In combination, a screw having a longitudinal bore therein, a plunger slidable in said bore, said plunger having a contact nut at one end thereof, a switch housing mounted for rotation on the small end of i said screw and arranged 'to enclose one end of said plunger and said nut, electrical conductors entering said housing and having terminals arranged to be contacted by said nut, means to urge said nut into contacting relation with said terminals and means to limit the movement of said nut away from said terminals.

26. In a device of the character described, including a hinge, a threaded hollow stud having a iiared and recessed head and arranged to secure one leaf of said hinge to an automobile frame, a plunger slidable in said hollow stud and having an end arranged to be contacted by the other leaf of said hinge, a contact nut threaded onto the other end of said plunger, a switch housing mounted fo'r rotation on the reduced end of said stud, electric conductors carried by said housing and terminating at one end `in elements adapted to be contacted by said nut and terminating at the other end in male terminals extending beyond the end of said housing.

27. The structure of claim 26, including means in said housing for ,preventing the rotation of said nut.

JOHN W. LILEY.

References Cited in the iile of this patent UNITED STATES PATENTS Number Name Date 1,483,399 Whittington Feb. 12, 1924 1,529,429 Gross Mar. 10, 1925 1,622,541 Raley et al Mar. 29, 1927