CA1120108A - Electric cigar lighter - Google Patents

Abstract

Abstract of the Disclosure An electric cigar lighter having a holder consisting of a socket with two contacts which form part of a cigar lighter circuit. An ignition plug adapted to be positioned in the socket. The plug having a heating element and a switch for energizing the heating element in response to manual operation of the plug. The plug further including a bimetallic member adapted to de-energize the heating element by opening the switch in response to heat-ing by the element. The bimetallic member is engaged at the peripheral portions thereof by a clamping means having an abutment member and a coil spring engaging opposite sides of the bimetallic member.

Description

~ 0~08 ELECTRIC CIGAR LIGHTER

This invention relates generally to cigar lighter de-vices for automobiles and the like, and more particularly to lighters which are especially adapted to heat to useful in-candescence in relatively short intervals of time.
In the past, a large number of different lighter con-struc~ions have been proposed and produced. Generally they employed bimetallic spring fingers carried in a socket and which were engageable with the side surfaces of a heating element cup that was carried on the inner end of the ignitor plug. When the plug was depressed, the fingers latched over the sides of the cup, establishing a circuit through the heating 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 the same to retract and break the circuit through the element.
Numerous refinements to this basic structure have been achieved over the years. However, problems sometimes arose, as when one of the bimetallic fingers, for reasons sometimes obscure, shifted into the path of the ignitor plug while the latter was being depressed, resulting in breakage and pos-sible short-circuiting o~ the socket. This would cause ei-ther a blown fuse or else a burned-out wiring harness, de-pending on the degree of current overload protection built into the particular electrical system of the automobile.
In other cases, the bimetallic fingers underwent an aging deformation after prolonged use. When this occurred, the socket usually had to be removed, in most cases involving work underneath or to the rear of the dashboard. Where the socket was not readily accessible, such repair or replace-ment w~s sometimes difficult and time consuming.
Typically there is a period of ten to fifteen secondsfollowing actuation of such ignitor plugs, until the heating element has reached use~ul incandescence and the plug snaps out in readiness for use. In the past, a number of efforts have been made to reduce this waiting time to just a few seconds. Generally, such innovative units have employed a bimetal disk disposed adjacent to the heating element, the disk constituting one contact of a switch which was adapted to open after the element reached incandescence. By posi-tioning the disk right next to the element, response times on the order of only several seconds have been achieved, particularly when an applied voltage which exceeded the con-tinuous rating of the heating elemen ~ was employed .
Prior lighters o~ the type employing bimetallic disks all had a number of distinct disadvantages. Generally where the contact area of the disk was at its center, the socket was arranged to secure the disk at its periphery. The mount-ing for the disk had to be such that it would not interfere with its flexing and snap-type movements. This imposed stringent requirements on the tolerances of both the disk and the part which carried it. Also, in most cases the disk con-stituted part of the "hot" side of the circuit, and thus hadto be insulated from the remainder of the socket. Accord-ingly, such mountings were often awkward, and prone to mal-function 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 prob-lem with this arrangement was that the support area was too small, and the disk eventually loosened, causing poor elec-trical contact with the stud. Or, if the support area wasmade sufficiently large, then its freedom of movement was impai~ed, as was its proper functioning. Since both the stud and the disk were current-carrying member~, any loos-ening aaused either excessive voltage drops, or else open circuits, resulting in malfunction or failure of the device.
Where the bimetallic disk itself was employed as one contact of the circuit-breaking switch, there occurred burning and pitting at the points of contact, this resulting in both a poor electrical connection and in deterioration of the disk itself, after a relatively short period of use. Moreover, where the disk was a current carrier, the relatively heavy current flow associated with such 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 of the elec-trical 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.
Generally, the heating element of a cigar lighter is carried in a metal cup at the inner end of the ignitor plug.
With spiral wound ribbon or coil type elements, the outer-most convolution of the coil i5, as a rule, secured by weld-ing it to the annular wall of the cup. A slitted rivet or stud is disposed in the bottom wall of the cup, with the other end of the coil being inserted and secured thereto.
Since the cup constituted a current carrying member in the "hot" side of the circuit, it required special materia' in order to insulate it from the remainder of the ignitor plug, as well as from the rivet, which is in the "cold" side of the circuit. Various arrangements for mounting the cup and rivet were employed. Different combinations of insulating ~lZ0108 bushings and/or washers generally met with success, a~ a rule. But with such constructions, o~ course, care had to be exercised in the assembly, in order to insure proper seating of the washers, and to make certain that short-circuiting of the rivet to the cup would not occur.
U. S. Patent No. 3,870,857 dated March 11, 1975, and issued to Laurence G. Horwitt shows a recently developed arrangement for mounting a heating element cup and rivet, wherein the cup is insulated from the remainder of the ig-1~ nitor plug by means of a mica washer. A series of nibs on the bottom wall of the cup is received in corresponding re-cesses in a transverse wall of the plug body, with the mica washer being sandwiched between the two walls. This permits the use of automatic assembly e~uipment, in that the nibs of the cup can become seated in the recesses of the transverse wall, as a consequence of proper rotational orientation of the cup and plug body. This construction has met with wide acceptance and considerable success due to the savings of labor, while maintaining reliability.
The present invention provides an electric cigar light-er, comprising in combination a holder device including a socket having two contacts forming part of a cigar lighter circuit, an ignitor plug receivable in the socket, said plug having a manually operable part, a heating element carried at the inner end of the plug, means fior establishing a cir-cuit from the holder device contacts through the heating element, said means including an electrical switch having cooperable parts carried by the ignitor plug, means for closing said switch and energizing said heating element in response to actuation of said manually operable part, means responsive to heating of said heating element, for opening said switch to de-energize the element, said immediately " 11~Z0~08 preceding means including a bimetallic member carried by ~aid plug and having a circuit-opening position and a closed-circuit position, said member having a central bimetallic actuator portion which is adapted to actuate one of the co-operable parts of said switch to effect said opening of the switch, and clamping means engaging peripheral portions of said bimetallic member, said clamping means comprising an abutment member and a coil spring engaging opposite sides of the bimetallic member.
Other features and advantages will hereinafter appear.
In the accompanying drawings, Fig. 1 is a vertical sec-tional view of the cigar lighter showing the ignitor plug disposed in the holder device or receptacle, in its unener-gized or storage position wherein a switch carried by the plug is open. The bimetallic switch actuator member or disk is in its circuit-opening position.
Fig. 2 is a view like 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 device and prior to its return-after finger pressure is removed. Its cooperable switch parts have been closed to effect energization of the heating element. The bimetallic switch actuator disk is in its closed-circuit position.
Fig. 3 is a view like Figs. 1 and 2, wherein the bime-tallic member or disk associated with the switch is still in its closed-circuit position and is being rapidly heated due to its closer proximity to the energized heating element.
The spacer member 50 and knob 51 have returned to the posi-tion of Fig. 1 due to the removal of finger pressure.
Fig. 4 is a right end elevation of the contact cup carried by the ignitor plug shown in Figs. 1-3, the cup con-stituting one of the cooperable switch parts.

OiO8 Fig. 5 is a left end elevation of a bearing cup carried by the ignitor plug, for enabling limited ~liding movement of the contact cup with respect to the plug body.
Fig. 6 is a side elevational view of the bimetallic member or disk associated with the ignitor plug of Figs. 1-3.
Fig. 7 is a right end elevational view of a heating ele-ment mounting me~ber or mounting cup carried by the ignitor plug of Figs. 1-3.
Fig. 8 is a right end elevational view of a contact member or terminal element which carries the heating element, the contact member being associated with the mounting member of Fig. 7 in the ignitor plug of Figs. 1-3.
Fig. 9 is a left end elevational view of a dish-shaped contact mem~er carried in the socket of the igniting unit of Figs. 1-3.
Fig. 10 is a view, partly in side elevation and partly in section, of a tubular friction sleeve associated with the ignitor plug of Figs. 1-3.
Fig. 11 is a fragmentary section of the sleeve of Fig.
10.

Fig. 12 is a side elevational view of a tubular ash-guard associated with the ignitor plug of Figs. 1-3.
Fig. 13 is a front elevational view of the ignitor plug of Fig. 1, except with the kno~ removed.

.

Referring first to Figs. 1-3 there i8 illustrated a cigar lighter of the type adapted to be mounted on an auto-mobile dashboard, comprising a receptacle or holder device 12 which includes a socket, and a generally cylindrical ig-nitor plug 14. ~he receptacle 12 has a radially outwardly extending annular flange 16 which engages the front surface of the automobile dashboard 18. At the rear, the receptacle mounts a threaded shell 20, on which there is screwed a tu-bular clamping shell 22 having a corresponding threaded por-tion 24 mating with the shell 20. The front end of theclamping shell bears against the rear surface of the dash-board as shown, to thereby hold the receptacle 12 in a fixed position thereon.
The receptacle or socket 12 has a dish-shaped metal contact member constituting one of the socket contacts 26, which is insulatedly mounted therein by means of a threaded stud 28 and nut 30. Carried on the stud are insulating washers 32, 34 and a spring washer 36. The stud extends through aligned apertures in the inner transverse wall 38 of the receptacle 12 and in the transverse or bottom wall 40 of the screw shell 20, thereby to retain the contact mem-ber 26, receptacle 12 and screw shell 20 in assembled rela-tion. The transverse wall 40 includes alignment nibs 42 which are stamped out therefrom and which extend into cor-responding apertures 44 in the shell. These key the shell 20 to the remainder of the receptacle 12 and prevent rela-tive turning movement bewteen the two parts during instal-lation o~ the unit.

As shown, the contact member 26 has a conical seat 46 at its center. The diameters of the aligned apertures in the walls 38, 40 exceed the diameter of the stud 28 by a substantial amount, thereby providing clearance space between the walls of the apertures and the stud to insure adequate insulation of the stud. Similarly, the diameter of the hole in the spring washer 36 is sufficiently large to provide adequate clearance around the stud. The portion 48 of the washer 32 is deformed to extend partially into the aperture in the transverse wall 38 of the receptacle 12, and the conical seat 46 thus centralizes the stud with re-spect thereto during assembly.
Referring again to Fig. 1, the ignitor plug 14 includes a tubular plug body assemblage 49 comprising a manually op-erable part or spacer member 50 and a knob 51, the member 50 being generally in the form of a hollow cylinder. A friction sleeve 52 is telescopically carried on the spacer member 50, and a retractable ashguard generally designated 54 and par-ticularly illustrated in Fig. 12 also constitutes part of the plug body assemblage and is telescopically carried by the spacer member 50 and movable thereon between limits, as will be later brought out. Disposed at the end of the spacer member 50 is a cap 56 having an annular flange 58 extending past the periphery of the member 50. The cap 56 has a series of slots 60, as shown in Fig. 13, and corre-sponding lugs 62 on the spacer member extend through the slots and are bent radially inward to thereby hold captive the cap 56. The cap 56 also has a central indented portion 64 which is apertured to receive a threaded mounting stud 66 of the knob 51. The cap 56 includes an integral spring pressure tooth 70 which engages the threads of the stud and enables the knob to be merely screwed into the cap as shown.
The flange 58 constitutes a seat for one end of a coil spring 72, the other end of the spring bearing against an in-ternal shoulder 74 on the friction sleeve 52 and the latter having an outwardly extending annular curl ~D which normally bears against a transverse shoulder 82 on the spacer member 50. As shown in Fig. 12, the ashguard 54 has a series of lugs 84 struck from its annular wall portion. In the present construction, three such lugs are disposed circumferentially about the body of the guard. The lugs 84 project inwardly into the path of the curl 80 when the ignitor plug is being withdrawn from the socket, and position the ashguard so as to encircle a heating element to be described below, as the plug is removed from the receptacle. The ashguard 54 fur-ther includes a circumferential bead 86 which is engaged byone or more spring fingers 88 lanced from the annular wall of the receptacle 12. The fingers include camming portions 90 which limit outward or rearward axial movement of the ashguard when the ignitor plug 14 is being withdrawn, as there occurs engagement of the ends of the lugs 84 with the curl 80 of the friction sleeve 52. This results in the heating element being recessed within the ashguard at such times that the ignitor plug is withdrawn from the socket.
At its front end the friction sleeve 52 has an outward-ly extending annular flange 92 which normally bears againsta corresponding flange 94 on the ashguard 54. The limits of relative axial movement of the friction sleeve 52 with re-spect to the ashguard 54 are thus determined in one direction by the engagement of the flanges 92, 94 and in the other direction by engagement of the curl 80 with the lugs 84 of the ashguard.
In order to provide a smooth, non-binding and sliding engagement between the friction sleeve 52 and the ashguard 54, there are provided on the cylindrical exterior surface of the sleeve a plurality of circumferentially spaced lon-gitudinal ribs 96 which slidably engage the inner cylindrical surface of the ashguard. These ribs are particularly illus-_ g _ trated in Figs. 10 and 11, and operate to reduce binding between the parts and prevent axial misalignment thereof.
In order to exert frictional resistance against relative axial movement of the friction sleeve 52 and the ashguard 54, the cylindrical body of the sleeve is lanced at several locations, preferably spaced circumferentially about the sleeve, providing yieldable friction fingers 98 which bear with calibrated pressure against the inner cylindrical sur-face of the ashguard. The pressure is sufficient to retain the ashguard in any selected axial positions to which it is moved with respect to the sleeve. The ribs 96 of the sleeve assure constant uniform spacing between the two parts, to prevent undesirable variations in the side pressure exerted on the inner surface of the guard by the friction fingers 98. Accordingly, the base area of the fingers 98 will not be "sprung" by improper alignment. Disposed at the inner end of the ignitor plug 14 is a spiral-wound heating element or coil 104 which can be constituted as a ribbon of "V"
cross section with successive convolutions interlocking one another to form a disk-like structure.
There is provided a mounting arrangement for the heat-ing element, involving mainly a single metallic, dual-function member which effects both a mechanical support for andelectrical insulation between the opposite ends of the heating element 104. In the assemblage involving such dual function member there is included an annular, metal terminal element 106 which is particularly illustrated in Fig. 8, having an outer wall 108 and a curled-in rim 110. As shown, the heating element 104 is disposed within the terminal ele-ment 106, with its outer end or terminal portion 112 secured by being sandwiched or crimped under the rim 110. This can be accomplished in a suitable punch and die (not shown) which effect both the initial curling operation and the final crimping operation in a single step. By such arrangement, the outer terminal portion 112 of the heating element 104 is permanently both mechanically secured and electrically con-nected to the terminal element 106.
The terminal element also functions as a contact member;
in this connection there is provided an inturned flange 114 lying substantially in a radial plane, having a series of resilient lugs 116 extending inwardly therefrom. These lugs 116 are adapted to engage the dish~ e contact member 26 of the receptacle 12 when the ignitor plug 14 is in the posi-tions of ~igs. 1, 2 and 3. The lugs 116 are formed with strengthening, spacer ribs 118 which protrude toward the heating element 104 from the plane of the flange 114 and engage the outermost element convolutions to provida me-chanical support thereto.
The dual-function member comprises an anodized aluminum mounting member or mounting cup 120 in which the terminal element 106 is nested. The mounting member 120 has three lugs 123 shown in Fig. 7 which are bent inward after the assembly with the terminal element 106, thereby to hold cap-tive the terminal element 106, and the mounting member has an annular side wall 122 and bottom wall 124 provided with a tubular boss 130 defining a central aperture 126 (Fig. 7).
The bottom wall 124 of the mounting member 120 also has a series of circumferentially-spaced heat-passages or holes 128 surrounding the central aperture, for purposes shortly to be described. The inner surface of the annular wall 122 of the mounting member 120 engages the annular external sur-face area of the wall 108 of the metal terminal element 106 but remains adequately electrically insulated therefrom by virtue of the anodizing of the mounting member.

~lZ0108 Pressed into the boss 130 is a metal rivet 132 consti-tuting a second terminal element which is connected to the innermost end 134 of the heating element 104. The surface of the boss 130 which engages the rivet 132 also has an in-sulating anodized coating, enabling the rivet to remain elec-trically insulated from the mounting member 120 even though it is mechanically secured thereto. The rivet 132 has a stop shoulder 136 and is slotted to receive the inner end portion 134 of the heating element.
There is provided a two-part electrical switch con-nected in circuit with the heating element 104, and a bi-metallic actuator member 146 associated therewith, adapted to open the circuit through the element after it has reached useful incandescence.
One part of the switch comprises a mova~le contactor device or contact cup 142 which is particularly illustrated in Fig. 4, and the other part includes a contact portion or surface 144 on that end of the rivet 132 which extends for-ward from the boss 130. The bimetallic member or operator 146 is in the form of a disk (Fig. 6) having a central aper-ture 147 surrounded by an actuator portion which is adjacent to the contact cup 142 of the switch. As shown, the disk 146 lies in a plane which is generally perpendicular to the a~is of the plug body 50. A bearing cup 148 constituting a guide for the contact cup 142 is also provided, said bearing cup having outer and inner concentric annular walls 150, 152 respectively connected by a conical wall 154. The bearing cup is closely-fitted in the body or spacer member 50, and seats against an annular internal shoulder 156 therein.
The walls 150 and 154 together form a seat for one end of a compression coil spring 158, the other end of which bears against one face of the bimetallic disk 146. The peripheral 0~08 portions of the other face of the disk 146 seat against an annular shoulder 160 on the anodized mounting member 120.
The disk is thus sandwiched in an operative position between the member 120 and the spring 158 even when the latter under-goes compression, as will be explained below.
Referring again to Figs. 1-3, the contact cup 142 has an annular wall 162 which has a sufficiently loose, non-binding fit with the wall 152 of the bearing cup so as to enable free sliding movement o~ the two parts. A compres-sion coil spring 164 is carried by the contact cup, engagingthe transverse or bottom wall 166 thereof and having its other end seating against a transverse or bottom wall 168 of the bearing cup 148. The wall 166 of the cup 142 com-prises an inwardly offset portion 170 which constitutes a contact surface for engagement with the contact portion 144 of the rivet 132. In addition, at the center of the offset 170 is an aperture 172 of smaller diameter than the dimen-sions of the end of the rivet 132, this construction result-ing in a more even distribution of contact pressures of the switch.
Referring again to Figs. 1-3, it can be seen that the aperture of the bimetallic disk 146 provides clearance for the rivet 132 and boss 130 of the mounting member 120. As shown, sufficient clearance is provided so that no engage-ment between the two parts occurs. The spring 164 normally maintains the wall 166 of the contact cup 142 in engagement with the central portions of the disk 146 for the open-circuit condition of the lighter shown in Fig. 1.
It will be seen from Figs. 1-3 that although the disk 146 is at "ground" or return-circuit potential, it does not at any time carry the heating element current, because of its mounting. The spring 158 and shoulder 160 constitute a .

)108 means which mounts the bimetallic member 146 in the plug 49 so as to maintain the central bimetallic actuator portions thereof out of contact with any parts of the heating element circuit when the member is in the closed-circuit position of Figs. 2 and 3. In some of the appended claims, the mounting member is referred to as an abutment member, since it backs up or abuts the bimetallic member 146, and together with the spring 158, constitutes a mounting therefor.
The operation of the lighter may now be readily under-stood by referring to Figs. 1-3 in succession. Fig. 1 il-lustrates the relative positions of the various components with the lighter in the storage or unactuated position, wherein the positive terminal of the battery is intended to be connected to the stud 28, this being conveniently here-inafter referred to as the "hot" side of the circuit. The other terminal of the battery is connected to the vehicle dashboard 18, constituting the return side of the circuit.
It is noted that with the component positions of Fig. 1, the lugs 116 of the contact member 106 (Fig. 8) are in en-gagement with the dish-like contact member 26 of the socket.
No current flows through the heating element, however, since the switch parts 132, 142 are disengaged by virtue of the bimetallic disk 146 biasing the contact cup 142 toward the left.
When it is desired to use the lighter, the manually operable part comprising the knob 51 and spacer or body mem-ber 50 is depr~ssed in the socket from the shallow position of Fig. 1, to the deep position of Fig. 2. This accom-plishes several things. The spacer member 50 has carried the bearing cup 148 toward the right, while the mounting member 120, contact member 106, and heating element 104 re-main stationary. The hard anodizing of the aluminum mounting 11;~0~08 member 120 presents a good slide bearing surface in engage-ment with wall 176. This enables a smooth movement to occur between these parts as the knob 51 is being depressed. The unitary assemblage consisting of the mounting member 120, contact member 106, and heating element 104 remains station-ary. A peripheral flange 180 on the spacer member 50, which engages and holds captive the mounting member 120 for the position of Fig. 1, now has shifted and is engaged with the wall 38 of the receptacle. Compression of the spring 158 causes a tight engagement of the contact lugs 116 (Fig. 8) with the dish-like contact member 26, insuring good elec-trical contact therewith. Initially the bearing cup 148 and contact cup 142 have moved as a unit, until the latter be-came engaged with the contact portion 144 of the rivet, after which further movement of the bearing cup 148 effects com-pression of the spring 164, causing firm engagement of the wall 170 with the rivet contact portion 144. While the bearing cup 148 and contact cup 142 are initially moving together, a point is reached where the bimetallic disk 146 (still cold) snaps under the action of the bearing cup from the open-circuit position of Fig. 1 to the closed-circuit position of Fig. 2. This occurs before and during engage-ment of the cup wall 170 with the rivet 132. With the com-ponents in the relative positions of Fig. 2, a circuit is completed through the heating element 104 as follows:
Current flows from the stud 28 through the contact member 26 to the contact member 106, through heating element 104 to the rivet 132, then to the contact cup 142 and spring 164 and to the cup 148, through the spacer member 50, fric-tion sleeve 52 and ashguard 54 to the receptacle 12 and the panel 18. Portions of the inner walls of the receptacle 12 constitute one of the two contacts in the receptacle. Figs.

~i~oio~

1-3 show in dotted outline one of the three friction finger~
98 on the friction sleeve 52. These bear against the inner surface of the ashguard 54, and thus insure good electrical contact therewith. After depressing the knob 51, the user removes the pressure, and the spacer member S0 and knob 51 are returned to the Fig. 1 position under the action of the spring 72, but the spring 164 now expands and maintains the contact between the cup 142 and rivet 132. This is illus-trated in Fig. 3. After several seconds have elapsed, the heating element 104 reaches useful incandescence, and heat is transferred by radiation through the holes 128 (Fig. 7) to the bimetallic disk 146. When the disk has heated suf-ficiently, it snaps back to the position illustrated in Fig.
1, at the same time effecting disengagement of the cup 142 and rivet 132. This opens the circuit through the heating element 104. At the time that the disk snaps back to the position of Fig. 1, an audible click is heard, indicating to ~he user that the lighter is now ready for use.
As the knob 51 and spacer member 50 are withdrawn from the socket 12, the ashguard 54 at first remains stationary by virtue of the engagement of the bead 86 with the spring fingers 88. Thus, the spacer member 50, friction sleeve 52, cups 142, 148, mounting member 120, and heating element 104 move together as a unit with respect to the ashguard 54 until there occurs engagement of the lugs 84 and the outward an-nular curl 80 of the friction sleeve, following which the components listed above and the ashguard move as a unit.
The heating element 104 is now recessed within the circular edge of the ashguard by 1/4 inch or so. Under such circum-stances the annular flange 92 of the friction sleeve 52 isspaced a short distance from the flange 94 of the ashguard 54 while the ignitor plug is out of the socket.

01~08 Upon reinstallation in the socket, the knob 51 is de-pressed a sufficient amount such that, after the ashguard flange 94 engages the socket flange 16, the friction sleeve 52 and spacer member 50 continue to move with respect to the ashguard until the flange 92 engages the flange 94. This corresponds to full retraction of the ashguard with respect to the contact member 106 and heating element 104. At this point the user will experience additional resistance toward further insertion of the knob and spacer member into the socket, and the nesting engagement of the flanges 92, 94 will provide a visual indication to the user that the plug is now returned to the normal, unenergized or storage position.
The above construction is seen to have the following advantages, resulting in improved operation and long life expectancy. In contrast to many of the prior art arrange-ments wherein a bimetallic member was riveted or otherwise secured in place, the central switch-actuating portion of the bimetallic member of the present construction is free and clear of attachment to other parts of the device, this resulting in simplified assembly and greater relia~ility on the part of the member, since there exists nothing to inter-fere with the normal snap or flexing movements thereof.
Because the contact areas of the two-part switch are inde-pendent of the member or disk, the latter does not undergo any deterioration due to arcing or pitting of switch contacts.
Also the bimetallic member does not suffer any appreciable wear or abrasion. Accordingly, its function is not impaired even after extended periods of use. Moreover, since the member is not a part of the electrical circuit, no current flows through it; accordingly there is eliminated from the design of the lighter, undesirable variables relating to the physical electrical-resistance characteristics of the member itself, such as the self-heating effect were current to be flowing through it, or contact and surface resistances as-sociated therewith. The response of the bimetallic member is thus governed entirely by heat transferred to it by radi-ation from the heating element. The action of the bimetallic mem~er is not affected by variations in the applied voltage due to changes in charging rate, load changes on the vehicle electrical system, etc. Moreover, with such an arrangement, there is retained in the lighter design the high reliability inherent in a simple bimetallic disk, the latter being vir-tually unmodified when installed and used in the ignitor device. The close proximity of the bimetallic member to the heating element results in a relatively quick response, en-abling the use of a heating element which heats rapidly at the applied voltage, typically within several seconds, with-out danger of over-heating or burnout.
The combination involving the mechanical support for the heating element represents a very workable solution to the problem of properly mounting it at the inner end of an ignitor plug. There is eliminated the use of insulating washers and bushings, thus minimizing the possibility of short-circuiting; simplified assembly is thus realized, with no sacrifice in overall reliability.
In the present construction, unlike many other cigar lighters built in the past few years, the ignitor plug does not move outwardly from the socket when the heating coil has reached incandescence. But the unit still provides an audible "click" when ready, as the bimetallic member opens the switch.
There are no sudden acceleration or deceleration "impulse"
forces applied to the heating element, as will be understood.
This has been a problem in other lighter designs, since im-pulse movements experienced by many of the devices heretofore llZOlOB

known resulted in severe mechanical shock to the heating ele-ment, these being especially damaging when the element was in an incandescent state. Weakening and fatigue of the element eventually occurred as a result. It should be realized that the heating element ribbon weakens physically as its tempera-ture is increased. Also, by the present construction which involves no bimetallic spring fingers, there is eliminated the possibility of the plug popping completely out of the soc~et. This was a problem in some prior units, wherein the inertia of the plug as the fingers releas~d the heating ele-ment cup could cause the plug to eject.
In the present construction all critical or moving parts are carried in the ignitor plug and not in the socket.
Should failure e~er occur it is most likely to be associated with parts carried by the plug, and not the socket. Accord-ingly, by the present construction, servicing is simplified since it involves a mere replacement of an ignitor plug rather than a repair of the socket. Since the socket con-tains so few parts, there is little or no occasion for main-tenance or servicing of the same. While there are a numberof separate components involved in the present lighter, they are readily assembled to one another without reliance on special tools, and without involvement in critical position-ing or placement of the parts. Accordingly, some production steps can be handled by automatic assembly equipment, re-sulting in low costs, especially where manufacturing runs of several hundreds of thousands of units are being made.
The present lighter construction also features a conven-ient re-light capability. Following an initial energization, the plug can be quickly re-energized, since the resetting is effected by the depressing movement of the plug.

As a consequence of the features outlined above, many of 0~()8 the undesirable characteristics of prior lighter devices have been eliminated. There is thus provided a unit having substantially less likelihood of malfunction and failure, especially after a period of use involving thousands of re-peated operations under extremes of temperature normally experienced in automobiles and other vehicles.
The present invention is thus seen to represent a dis-tinct advance and improvement in the technology of cigar lighter ignitor devices.
Each and every one of the appended claims defines a distinct aspect of the invention separate from the others, and each claim is accordingly to be treated in this manner when the prior art devices are examined in any determination of novelty or validity.
Variations and modifications are possible without de-parting from the spirit of the invention, and certain por-tions of the improvement may be used without others.

Claims (10)

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

1. An electric cigar lighter, comprising in combination a holder device including a socket having two contacts form-ing part of a cigar lighter circuit, an ignitor plug receiv-able in the socket, said plug having a manually operable part, a heating element carried at the inner end of the plug, means for establishing a circuit from the holder de-vice contacts through the heating element, said means in-cluding an electrical switch having cooperable parts carried by the ignitor plug, means for closing said switch and ener-gizing said heating element in response to actuation of said manually operable part, means responsive to heating of said heating element, for opening said switch to de-energize the element, said immediately preceding means including a bi-metallic member carried by said plug and having a circuit-opening position and a closed-circuit position, said member having a central bimetallic actuator portion which is adapted to actuate one of the cooperable parts of said switch to effect said opening of the switch, and clamping means en-gaging peripheral portions of said bimetallic member, said clamping means comprising an abutment member and a coil spring engaging opposite sides of the bimetallic member.

2. The invention as set forth in claim 1, wherein said bimetallic actuator portion is free and clear of attachment to any other parts, said actuator portion being adapted for solely abutting engagement with said one switch part.

3. The invention as set forth in claim 1, wherein said manually operable part of the ignitor plug is moveable be-tween deep and shallow positions in said socket, and spring means biasing one of said cooperable switch parts into en-gagement with the other when the manually operable part of the ignitor plug is disposed in its deep position in the socket.

4. The invention as set forth in claim 1, wherein said ignitor plug includes means for mounting the heating element at the inner end of the plug, said mounting means comprising said abutment member, and a rivet carried thereby, connected with one end of said element, said rivet having a contact portion at one end, said contact portion constituting one of said cooperable switch parts.

5. The invention as set forth in claim 3, wherein said ignitor plug comprises a tubular plug body, said one coop-erable switch part comprising a contact cup, and means car-ried by the plug body and providing a guide to enable the contact cup to have limited sliding movement with respect to the body, as the cooperable switch parts are being brought into engagement with one another.

6. The invention as set forth in claim 5, wherein said guide comprises a bearing cup disposed in the tubular plug body, said cups having annular telescoping wall portions re-spectively slidably engaging one another, said spring means engaging bottom wall portions respectively of said cups.

7. The invention as set forth in claim 4, wherein said ignitor plug comprises a tubular plug body, the other of said cooperable switch parts comprising a contact cup carried by the plug body, said contact cup having a bottom wall pro-viding a contact surface for engagement with the contact portion of said rivet.

8. The invention as set forth in claim 1, wherein said ignitor plug comprises a tubular plug body, said abutment member carrying said heating element at the inner end of said body, said abutment member normally engaging peripheral edge portions of one face of said bimetallic member, and con-stituting a seat therefor.

9. The invention as set forth in claim 8, wherein central portions of said other face of the bimetallic member are engageable with one cooperable part of said switch, for effecting actuation of the same.

10. The invention as set forth in claim 8, and further including a rivet carried by said abutment member and secured to one end of the heating element, said rivet projecting be-yond adjacent portions of said abutment member, and consti-tuting one of said switch parts, means defining a central aperture in said bimetallic member, portions of said rivet extending through said aperture, for engagement with the other of said switch parts during actuation of said switch.