CA1115354A - Automatic electric cigar lighter with base switch - Google Patents

Abstract

ABSTRACT

An automatic electric cigar lighter for automobiles and the like, comprising a socket-presenting holder device and an ignitor plug receivable in the socket. The plug comprises a manually operable part carrying a heating element which can be electrically connected to the holder circuit, the latter having a normally open heat-responsive switch that becomes closed when the manually operable part is first pushed to a deep position in the holder device. The socket, in addition to its grounding circuit, has a "hot" contact that is engage-able with a cooperable contact on the plug to effect the cir-cuit through the heating element. The holder device also carries a bi-stable bimetallic member which is engageable with one of the parts of the normally-open switch to control the latter. The bimetallic member normally occupies an open-circuiting position wherein it abuts the one switch part to maintain the switch open. When the manually operable part of the ignitor plug is first depressed, the cooperable contact of the ignitor plug is brought into engagement with the "hot" con-tact of the socket while at the same time the bimetallic mem-ber is actuated to its close-circuiting position, this effect-ing energization of the heating element and resulting in rapid heating of the bimetallic member. After several seconds, the member snaps back to its circuit-opening position wherein it causes disengagement of the switch parts, resulting in de-ener-gization of the element. Central portions of the bi-stable bi-metallic member are free and not attached anywhere to any parts of the switch or socket, but instead are merely disposed in close proximity to the switch part, such that the member can quickly effect opening of the switch without need for mechanical securement of its central actuator portion. The advantage of the present construction over that of prior devices is that there are eliminated the many problems which were previously associated with conventional fastenings made to a bimetallic member, such as securing a contact to the member, etc. Im-proved reliability and operation, together with significantly lower manufacturing and assembly costs, are thus realized.

Description

s~4 AUTOMATIC ELECTRIC CIGAR LIGHTER WITH BASE SWITCH

This invention relates generally to automatic electric cigar lighter devices intended for use in automobiles and the like, and more particularly to lighters of this type which are especially adapted to heat to useful incandescence in relatively short intervals of time.
In the past, a large volume of automatic electric cigar lighter constructions for automobiles has been proposed and pro-duced. Generally, such lighters employed a set of bimetallic spring fingers disposed in the socket of a holder device, which were engageable with side surfaces of a heating element cup carried at the inner end of the ignitor plug. When the plug was depressed, the fingers latched over the sides of the heat-ing element cup, establishing a circuit through the element.
As the element reached useful incandescence, the bimetallic fingers became heated and would then spread and release the cup and the ignitor plug, enabling these to retract and brea~
the circuit through the element.
Numerous refinements of this basic structure were achieved over the years. Even so, problems sometimes arose, as when one of the bimetallic fingers, for reasons often obscure, shifted into the path of the ignitor plug while the latter was being de-pressed, resulting in breakage and possible short-circuiting of the socket. This would cause either a blown fuse or else a burned-out wiring harness, depending on the type of current over-load protection built into the particular electrical system of the automobile. In other cases, the bimetallic fingers under-went an aging deformation after prolonged use. When this oc-curred, the socket usually had to be removed, in most cases in-volving work underneath or to the rear of the dashboard. Where the socket was not readily accessible, such repair or replacement - 1- ,,.; ~``~;) x~

became difficult, costly and time consuming.
Typically, in automatic lighters, there is a period of from ten to fifteen seconds following the actuation of the ignitor plug, until the heating element has reached useful incandescence that is sufficient to enable the plug to snap outin readiness for use. In the past, a number of efforts have been made to reduce this waiting time to just a few seconds. Several such innovative units have employed a bi metal disk disposed adjacent to the heating element, the disk itself constituting one contact of the switch which was adapted to open after the element reached incandescence. By positioning the disk right next to the element, response times on the order of only several seconds were achieved, particularly when an applied voltage was used which exceeded the continuous voltage rating of the heating element.
Various prior lighters of the type employing bimetallic disks had distinct disadvantages. Generally where the contact area of the disk was at its center, the socket was arranged to permanently fastenor mount the disk at its periphery. This mounting for the disk had to be such that it would not interfere with the flexing and snap-type movements thereof, thereby im-posing stringent requirements on the tolerances of both the disk and the part or parts which carried it. Also, in most cases, the disk constituted part of the current-carrying circuit, and thus had to be insulated from the remaining parts of the socket. Accordingly, such mountings were often awkward and prone to malfunction in use.
In other constructions, as where the contact area of the disk was at its periphery, the disk was mounted by means of a stud passing through a hole in its center, the end of the stud being staked to hold the disk in place. The problem with this arrangement was that the support area was too small, and the disk eventually loosened, causing poor electrical contact with i4 the stud. Or, if the support area was made sufficiently large, then its freedom of movement was impaired, as well as its proper functioning. Since both tAe stud and the disk were current-carrying members, any loosening caused either an excessive volt-age drop, or else an open circuit, resulting in malfunction or failure of the device. Where the bimetallic disk itself was em-ployed as one contact of the circuit-breaking switch, there oc- -curred burning and pitting at the points of contact, this re-sulting in both a poor electrical connection and in deterioration of the disk itself, after a period of use. Moreover, where the disk was a current carrier, the relatively heavy current flow associated with ignitor devices resulted in resistance-heating of the disk, aside from the heating effect due to its proximity to the coil. The resistance or self-heating effect depended on the resistances o~ the electrical path through the disk and stud;
there were thus introduced other undesirable variables into the design of the lighter, which caused problems during manufacturing runs where large numbers of units were to be mass produced, from components possibly having slightly different physical and/or electrical characteristics. In addition, in constructions where the bimetallic member was arranged to carry the heating element current, the response time of the member was very adversely af-fected by energy changes which occurred in the vehicle electrical system, such as drops in the supply voltage resulting from the application of momentary loads by other equipment in the vehicle, or surges in the supply voltage resulting from variation in the rate of charging by the vehicle's alternator or generator. Such variations in the applied voltage resulted in significant corre-sponding changes in the self-heating effect of the current on the bimetallic member, tending to exaggerate existing non-uniform-ities of response over prolonged periods of operation and under different environmental conditions.

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Applicants' U.S. application, U.S. Serial No. 868,935 filed January 12, 1978, discloses an arrangement for a fast-acting manual cigar lighter wherein the manually operable part of the ignitor plug is depressed and held for several seconds, to thereby close the heating element circuit and cause the element to reach incandescence, after which the circuit is automatically opened by a disk-like bimetallic member which is carried in the plug itself.
This particular construction has been found to operate quite well from the standpoint of good reliability and long life expectancy. The number of individual parts required in this prior design has led to attempts to simplify the con-struction somewhat, so as to reduce the overall manufacturing cost and result in easier assembly. Cigar lighters of the above type are typically built in manufacturing runs of thou-sands of units. Some of the newer luxury automobiles are pro-vided with four or more of such lighter devices; it can be readily appreciated that the annual sales of such units can easily run into the hundreds of thousands. Accordingly any saving which can be realized, as by reducing the number of parts involved, reducing the cost of such parts, and simplifying the assembly, becomes especially important from an economic stand-point. Of course, while it is considered desirable to reduce the costs of such items as much as possible, it should be real-ized that these devices must perform in a satisfactory manner, with complete freedom from jamming or malfunctioning, over the projected life of the automobile, which can be a number of years.
Conceivably such devices can be subjected to thousands of oper-ations over the life of the car, and in fact, production samples are tested for performance in excess of such figures.
The above drawbacks and disadvantages of prior cigar lighters are obviated by the present invention, which provides an auto-matic electric cigar lighter, comprising in combination a holder device including a socket having two contacts forming part of the cigar-lighter circuit, an ignitor plug receivable in the socket, comprising a manually-operable part movable in the socket between energizing and de-energizing positions, said plug having a heating element carried at its inner end, means for establishing a circuit from the holder device contacts through the heating element when the said manually operable part is shifted to its energizing position, the said means including an electrical switch having normally open relatively-movable cooperable contact parts carried by the holder device, and means becoming operative in response to heating of said heating element, for opening said electrical switch to break said circuit and de-energize the element, said means including a bimetallic member carried by said holder device and having a circuit-opening position and a closed-circuit position, said bimetallic member having an actuator portion which is free and clear of permanent attachment to any other parts of the holder device, said actuator portion being adapted to shift one of the cooperable contact parts of said switch to effect the opening thereof.
Other features and advantages will hereinafter appear.
In the accompanying drawings:
Fig. 1 is an axial sectional view of the improved automatic electric cigar lighter of the present disclosure, showing the ignitor plug disposed in the holder device or receptacle, in its unenergized or storage position and wherein an automatically-controlled switch carried by the holder device is open. The bi-metallic switch actuator disk or member is in its open-circuit position.
Fig. 2 is a view like that of Fig. 1 but partly in elevation, showing the manually operable part of the ignitor plug as having been shifted to a deep position in the socket of the holder de- ~ -vice. The bimetallic operator has been shifted to its closed-~ 3.1~ ;4 circuit position, and the switch has been closed whereby there is effected the energization of the heating element.
Fig. 3 is a view like that of Figs. l and 2, except that the manually-operable part of the ignitor plug has been released, and has returned to its forward position in the holder device socket. The bimetallic member or disk associated with the switch is being rapidly heated due to its close proximity to the ener-gized heating element, and will shortly shift from its closed-circuit position to its circuit-opening position of Fig. 1, thereby separating again the switch contact parts and opening the circuit through the heating element.
Fig. 4 is a right end elevation of an insulating slide and terminal block carried by the holder device of the lighter of Fig. 1-3, on which one of the socket contacts is mounted.
Fig. 5 is a side elevational view of the block of Fig. 4.
Fig. 6 is an axial sectional view of one of the switch parts of the automatically-operated switch.
Fig. 7 is an end elevational view of the switch part of Fig. 6.
Fig. 8 is an axial sectional view of an insulating bushing of the electrical switch.
Fig. 9 is an end elevational view of the bushing of Fig. 8.
Fig. 10 is an axial sectional view of the other part of the electrical switch.
Fig. 11 is an end elevational view of the switch part of Fig. lO.
Fig. 12 is a plan view of the bimetallic member or actuator for the electric switch, and Fig. 13 is a section taken on the line 13-13 of Fig. 12, Referring first to Figs. 1-3, the improved automatic elec- -tric cigar lighter comprises in its basic make-up a holder de- -vice 20 which presents an outwardly-facing socket 22, and an ignitor plug 24 which is removably carried by the holder device.

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The ignitor plug 24 has a manually operable part in the form of a cylindrical body 26 which carries at its front a cap 28 provided with a threaded aperture to receive the screw 30 of a manually engageable knob 32.
Slidably carried by the plug body 26 is a cylindrical friction sleeve 34 having an out-turned front flange 36 which is located forwardly of a bezel 38 on a cylindrical holder de-vice body 40 that is attached to a supporting panel 42 by means of a clamping sleeve 44. The rear or inner end of the body has screw threads 46 engaged by cooperable threads 48 of the clamping sleeve 44, as shown.
The friction sleeve 34 adjacent its inner end has an annular shoulder 50 which is engaged by a helical coil spring 52 that also engages the front cap 28 of the ignitor plug. The cap 28 has a back-turned annular flange 54 which is slidable in the friction sleeve 34 and constitutes a bearing therefor.
~ isposed rearwardly past the shoulder 50 of the friction i sleeve is a cylindrical portion 56 of reduced diameter, termi-nating in an out-turned annular flange 58 that is engageable with a ring-shaped anodized-aluminum insulating member 60 carried by a heating element cup 62 which is of known construction. The cup 62 contains a heating element 64 of spiral configuration, having its outer convolution or end crimped under an inward curl 66 of the cup and having its innermost end secured to a stud 68 which is carried in an eyelet 70 that is secured to the inner transverse wall 72 of the plug body 26.
The heating element cup 62 is insulated from the eyelet 70 and from the wall 72 by insulating and centralizing washers as shown.
Movement of the friction sleeve 34 on the body 26, as oc-casioned by expansion of the spring 52, is restricted in one direction, by engagement between the flange 58 of the sleeve and 3r~l the insulating ring 60 on the cup 62. In the opposite direction, the relative movement is restricted by the tightening and bunch-ing of the coil spring 52, which is seen to occupy the space be-tween the shoulder 50 of the friction sleeve and the cap 28 which carries the knob 32.
The ignitor plug 24 also includes a cylindrical ashguard member 76 having at its front end a flange 78 which is inter-posed between the flange 36 of the friction sleeve 34 and the bezel 38 of the holder device 20. The reduced portion 56 of the friction sleeve 34 slides on the exterior of the plug body 26, having a bearing thereon.
The friction sleeve 34 has spring fingers 80 which bear against the inside of the ashguard 76 to provide a sliding en-gagement therewith. The ashguard 76 has lanced fingers 82 which are engageable with the annular flange 58 of the friction sleeve to limit the projecting (rearward) movement of the ashguard on ~ ;
the ignitor plug 24, and the opposite movement of the ashguard is limited by engagement between the flange 78 thereof and the flange 36 of the friction sleeve.
The holder device 20 has a connector terminal 86 which is carried in an insulating block 88 having exterior threads 90 by which it is screwed into the threaded rear part of the body 40, against a rear transverse wall 92 thereof. The insulating block 88 can be molded or otherwise formed so thatithe terminal 86 forms an insert, such terminal having an inner head portion 94 in a bore 96 of the block.
The holder device 20 is provided with a unique, thermally controlled electric switching and contact means by which ener- -gization of the heating element 64 can be automatically controlled and safely effected during a relatively short tIme interval of several seconds duration. The electric switching, contact, and thermal timing devices are carried by the insulating block 88, l e ~ i4 and the assemblage includes a formed metal slider member 98 (see Figs. 6 and 7) that is slidably carried on the block 88, on a slide portion 100 thereof. The member 98 has a number of functions. It constitutes an active contact of th~ thermally controlled electric switch, and also constitutes a socket con-tact which is engageable with the heating element cup 62 of the ignitor plug 24. Additionally, it constitutes a slider which is movable axially on the insulating block 88 against the biasing action of coil springs.
As shown, the electric switching device comprises outer and inner, telescoping cylindrical metal members 104 and 106, the latter being an integral part of the member 98. An in-sulating sleeve 108 is interposed between the switch members, 104, 106 to provide insulation while at the same time permit-ting relative sliding movement therebetween. The switch mem-ber 104 has a transverse end wall 110 which is engageable with the end wall 112 of the member 106 to effect electric contact thereto, so as to conduct current between these members.
The slider member 98 has a circular or annular wall 114 which joins the contact portion 106 to the outer, slider por-tion 116 of the member. The insulating block 88 has a plural-ity of clearance slots 118 adapted to accommodate inturned flange portions 120 of the slider portion 116 so as to retain the member 98 in a given, forwardly-projected position as ef-fected by a helical coil spring 122 which has an end disposed in an annular groove 124 of the insulating block 88. The other end of the spring 122 bears against a bimetallic, switch-actuator disk 126 having a central aperture 128 by which it is enabled to be carried on the switching member 106. The outer periphery of the disk 126 is interposed between the spring 122 and the annular wall 114 of the member 98.

The disk 126 is of the bi-stable variety, by which it can sj4 occupy either of two bowed positions when it is in the cold state. These two cold positions are illustrated in Figs. 1 and 3, and the position of Fig. 1 is also illustrative of the heated position which the disk can occupy.
The inner peripheral portions 132 of the disk are adapted for abutting engagement with a flange 134 of the insulating sleeve 108 of the switch, and the switch member 104 has a flange 136 which is engageable with the insulating flange 134 and is held thereagainst by a helical coil spring 138 that also engages the head portion 94 of the connector terminal 86.
It will be seen that the annular wall 114 of the member 98 is interposed between the disk 126 and the heating element 64, and such wall is provided with a plurality of apertures 140 to enable an effective heat transfer to occur from the heating element to the disk.
The helical coil spring 138 is especially adapted to carry the heavy current for the heating element 64, and for this pur-pose it can be constituted of spring steel wire which is clad with copper, preferably by a process that results in a relatively thick copper overlay on the steel. The result is improved elec- ~ ;
trical conductivity by virtue of the copper component, and re-liable spring action due to the steel core.
The operation of the automatic electric cigar lighter can now be readily understood from an inspection of Figs. 1-3.
In Fig. 1 the cold or storage position of the lighter is shown.
The bimetallic disk 126 is bowed in such a manner that it main-tains the contact wall 110 of the contact member 104 out of en-gagement with the contact wall 112 of the slider member 98.
The coil springs 122 and 138, in conjunction with the bowed bi-metallic disk 126, maintain the annular contact wall 114 of the slider member (which constitutes the "hot" contact of the holder device 20) in engagement with the curled rim 66 of the heating element cup 62. Such engagement is also maintained by the friction fingers 80 of the friction sleeve 34 and detent fingers 144 which are lanced from the tubular body 40 and engage an annular shoulder 146 of the ashguard 76. The coil spring 52 improves the electrical conductivity, but can be omitted if desired.
The circuit from the multi-purpose slider-contact member 98 to the ground return of the holder device 20 can be readily traced from the engagement between the slider member and the heating element cup 62, from whence current goes to the outer convolutions of the heating element 64, then to the central convolution and rivet 68, then through the eyelet 70 and plug body 26, through the spring means 52 and friction sleeve 34, and lastly from the ashguard 76 to the holder device body 40 which latter is grounded at the panel 42. The holder device body 40 constitutes the "cold" contact of the socket 22, whereas the slider member 98 constitutes the "hot" contact of the socket member, being energized from the "hot" connector terminal 86.
To energize the lighter, the knob 32 is depressed as in-dicated by the arrow 148 in Fig. 2, and then let go. This action first flexes and bows the bimetallic disk 126 to an op- :
posite curvature as indicated in Fig. 2 and 3, by virtue of the peripheral portions of the disk being laterally displaced by the rearward movement of the slider member 98 and the fulcrumming action of an annular fulcrum portion 150 of the insulator block 88. The disk 126 snaps quickly to this opposite curvature, per-mitting the switch contact wall 110 to engage the switch contact wall 112 as shown in Fig. 2. Removal of the actuating force from the knob 32 will permit the ignitor unit 24 to return to its Fig. 1 position, as now seen in Fig. 3. However, contact re-mains established between the slider member 98 and the heating element cup 62, by virtue of the cooperation between the various 5.'~ 4 components already explained above. Current will now flow through the switch 110, 112 and through the heating element 64, causing incandescence of the latter. The radiant heat will pass through the apertures 140 of the slider member and quickly heat the disk 126, causing it to reversibly flex back to the Fig. 1 position, thereby opening the energizing circuit at the contact walls 110, 112. An audible click is heard upon such reverse snapping movement of the disk, thereby signalling the operator that the lighter is in readiness for use with the heating element 64 in an incandescent state.
After removal and use of the ignitor plug 24 it is rein-stalled to the position of Fig. l; the thermally controlled switch being now open, is in readiness for the next use.
We have found that the present automatic lighter is es-pecially effective and reliable in use. It provides a shortened period of time to effect the required incandescence, and safely .
opens the circuit through the heating element before excessive heating of the latter occurs even though the applied voltage to the lighter is greater than the continuous duty rating of the coil.
It will be seen that the construction of the lighter is characterized by a desirable symmetry and simplicity of the parts, there being concentricity about the axis of the ignitor plug and holder device. The operation of the part is simple and straightforward, and no permanent fastenings are used to retain the bimetallic disk, whereby the latter has full freedom to carry out its snapping movement as above explained.
In consequence, there is had an important economy in the manufacture of the lighter, while at the same time high reliabil-ity and precision of operation are achieved.

Claims (26)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An automatic electric cigar lighter, comprising in combination a holder device including a socket having two contacts forming part of the cigar-lighter circuit, an ignitor plug receivable in the socket, comprising a manually-operable part movable in the socket between energizing and de-energizing positions, said plug having a heating element carried at its inner end, means for establishing a circuit from the holder device contacts through the heating element when the said manually-operable part is shifted to its energizing position, the said means including an electrical switch having normally open rel-atively-movable cooperable contact parts carried by the holder device, and means becoming operative in response to heating of said heating element, for opening said electrical switch to break said circuit and de-energize the element, said means including a bimetallic member carried by said holder device and having a circuit-opening position and a closed-circuit position, said bi-metallic member having an actuator portion which is free and clear of permanent attachment to any other parts of the holder device, said actuator portion being adapted to shift one of the cooperable contact parts of said switch to effect the opening thereof.

2. The invention as defined in claim 1, and further in-cluding spring means biasing said manually operable plug part to its de-energizing position in the socket.

3. The invention as defined in claim 1, and further in-cluding means insulating said actuator portion of the bimetallic member from said one cooperable contact part of the switch when the bimetallic member is in its closed-circuit position.

4. The invention as defined in claim 1, wherein the bi-metallic member comprises a disk mounted within the rear portion of the holder device.

5. The invention as defined in claim 4, wherein said disk has two regions of large movement relative to each other, one of said regions constituting the actuator portion of the disk.

6. The invention as defined in claim 5, wherein the ac-tuator portion of the disk comprises the central region thereof.

7. The invention as defined in claim 5, wherein the central region of the disk has an aperture forming an inner periphery thereof, said electrical switch having a guide portion extending through the aperture of the disk.

8. The invention as defined in claim 7, wherein a peripheral part of the disk constitutes the actuator portion thereof.

9. The invention as defined in claim 7, wherein the guide portion of the electric switch constitutes one contact thereof.

10. The invention as defined in claim 9, wherein the guide portion of the electric switch has means constituting one of the socket contacts.

11. The invention as defined in claim 10, wherein the holder device has a slide, said means constituting one of the socket contacts, having a slider engageable with and movable on said slide to dispose said one socket contact in either an advanced or else a retracted position in the socket.

12. The invention as defined in claim 11, wherein the holder device has a connector terminal and an insulating block mounting the terminal, said insulating block having the said slide.

13. The invention as defined in claim 10, wherein the means constituting one socket contact provides a shoulder against which the disk abuts, and spring means maintaining said disk in abutting engagement with said shoulder.

14. The invention as defined in claim 1, wherein said elec-trical switch comprises a pair of telescoping metal cylinders and cooperable electrical contacts carried respectively by cor-responding ends of the cylinders.

15. The invention as defined in claim 14, and further in-cluding an insulating sleeve disposed between the telescoping cylinders, providing a sliding guide between the same.

16. The invention as defined in claim 14, and further in-cluding a pair of concentrically disposed coil springs surround-ing the outer of said cylinders, and means for transmitting force from said coil springs to said cylinders.

17. The invention as defined in claim 16, and further in-cluding a connector terminal on the holder device, one of said coil springs being adapted to conduct electrical current from the connector terminal to one of said cylinders.

18. The invention as defined in claim 14, wherein the electrical contacts of the telescoping cylinders comprise end walls thereof.

19. The invention as defined in claim 18, wherein one of said end walls is apertured to improve the contact capability thereof.

20. The invention as defined in claim 15, wherein the bi-metallic member comprises an apertured disk encircling one of said cylinders, and electrical insulation between said disk and the other of said cylinders.

21. The invention as defined in claim 4, and further in-cluding means enabling the ignitor plug, when the movable part thereof is in its energizing position, to exert a flexing force on the disk, and fulcrum means carried in the holder device, en-gageable with said disk to apply a force thereto which counters the said flexing force.

22. The invention as defined in claim 21, and further in-cluding a connector terminal on the holder device, and an in-sulating block mounting said connector terminal, said insulating block constituting said fulcrum means.

23. The invention as defined in claim 22, wherein central parts of the disk constitute the actuator portion thereof, said fulcrum means being circularly disposed and located radially outward of the central parts of the disk.

24. The invention as defined in claim 23 wherein the fulcrum means is circular.

25. The invention as defined in claim 4, wherein said elec-trical switch comprises an annular wall disposed transversely in the socket and carrying an electrical contact at its center, said annular wall being disposed broadside to said disk and arranged to be interposed between the disk and said heating element when the manually movable part of the ignitor plug is in its energizing position, said annular wall having apertures to enable radiant heat to pass to the disk from said heating element.

26. The invention as defined in claim 25, and further in-cluding fulcrum means carried in the holder device, for engage-ment with said disk at locations opposite to said apertures.