US2305084A

US2305084A - Cigar lighter

Info

Publication number: US2305084A
Application number: US265163A
Authority: US
Inventors: Arthur A Johnson
Original assignee: Automatic Devices Corp
Current assignee: Automatic Devices Corp
Priority date: 1939-03-31
Filing date: 1939-03-31
Publication date: 1942-12-15
Anticipated expiration: 1959-12-15

Description

De@ 15, 1942 A; A. JoHNsoN y 2,305,084

CIGAR LIGHTER Fued Marchv 51, 1939 2 sheets-sheet 1 ATTORNEYS A. A. JOHNSON 01111111 LIGHTER Filed Mar-Qn 31, v1959 2 Sheets-Sheet 2 me INVENTOR f A zur A.' Johnson ATTORNEYS Patented Dec. 15, 1942 UNITED STATES PATENT OFFICE Automatic Devices Corporation,

Bridgeport,

Conn., a corporation of Connecticut Application March 31, 1939, Serial No. 265,163

8 Claims. (YCI 2.19-32) This invention relates to cigar lighters, and, v

more particularly, to t-he type in which the igniting unit is removed from the holding device for use.

The removable igniting unit is usually provided with a friction sleeve or member which is adapted to engage the holding device to locate and hold the igniting unit in position thereon. This friction sleeve or member is usually mounted on the igniting unit so that a portion of the igniting unit can be moved relatively thereto to close an energizing circuit to a heating element carried by the igniting unit, and cooperates with means for yieldingly urging the movable portion of the igniting unit into a position in which the circuit is opened to the heating element.

According to the present invention, the friction sleeve or member is utilized as apart of the means to hold the igniting unity in closed-circuitl position until the heating element has attained its desired usable heat. f

This is accomplished by securing an element to the friction sleeve or member to form an abutment cooperating with a heat-controlled latch carried by the movable part of the igniting unit in such a manner that upon the movable part of the igniting unit being moved relatively to the friction sleeve, the latch will be caused to engage the abutment and hold the movable part of the igniting unit in closed-circuiI-position until the heating element has attained the desiredusable heat, whereupon the latch is released and the means for urging the movable part into opencircuit position moves the heating element relative to the friction sleeve or member to open the circuit.

The heat-controlled latch may either constitute an element of the circuit for the heating element which will open the circuit upon the heating element attaining al desired heat whereupon the yielding means moves the movable portion of the igniting unit into a position into which the circuit cannot again be made untillthe movable Dart of the igniting unitis again manually actuated, or the heat-controlled latch may be merely a detent for holding they circuit closed until it is opened by movement of the portion of the ignit-` ing unit upon release of the latch.

In the preferred form of the invention, the heat-controlled latch is carried in-the hollow of the igniting unit and the cooperating abutment extends therein to be engaged by the latch. With these elements so located Within the igniting unit, the danger of them being tampered with and their adjustment destroyed is eliminated.

Another feature 4of the invention resides in the placing of all of the control elements on the igniting unit. The igniting unit thus constructed can be associated with any one of a plurality of holding devices and will function properly with them all for the balance existing between the heatcontrolled latch and the means for urging the movable member into open-circuit position and against which it operates will have the same relation to one another irrespective of the holder in which the igniting unit is placed.

Other features and advantages ofthe invention will be apparent from the specification when considered in connection with the drawings, in which:

Figure l is a sectional view showing the igniting unit in open-circuit position.

Fig. 2 is a similar view to Fig. l, but showing the igniting unit in closed-circuit position and with a plan view of the circuit-control means.

Fig. 3 is a modified form of the invention shown in Figs. 1- and 2, showing a section view, with the igniting unit in closed-circuit position.

Fig. 4 is a sectional view of asimplified form of the invention, showing the igniting unit in open-circuit position.

Fig. 5 is a sectional view similar to Fig. 4, but showing the igniting unit in closed-circuit position.

Fig. 6 is a sectional view similar to Fig. 5, but showing a plan view of the circuit-control means.

Fig. 7 is a sectional view of a modified form of the invention shown in Figs. l to 6, with the igniting unit in closed-circuit position.

As shown in the accompanying drawings, the cigar lighter of the present invention comprises va, tubular holding device I0 which is adapted to slidably receive an igniting unit I I, which igniting unit is completely removable from the holding device for use.

The holding device has at its front end a turned out flange I2 adapted to engage the front face of a panel or dashboard I3 when the holding device is inserted through an aperture I4 in the panel. The other end of the tubular holding device is provided with a rear wall I5 to which is secured an externally threaded sleeve I5 having a reinforcing member II secured to one end thereof and engaging the end Wall.

Disposed in the bottom of the holding device adjacent the end wall is an insulating block I8 which supports contacts I9 and 20 and holds them in predetermined relation by means of recesses 2| and 22 which engage the contacts I9 and 20.

. The contacts are secured in place by means of a bolt 23 extending through and insulated from the sleeve l5, the contact I9 being clamped between a shoulder 23a on the bolt and the insulating block, and the contact being secured to the bolt by having the end of the bolt passing through the center of the contact and headed over as at 23h. Each of the contacts is provided with a contacting

surface

19a, 20a, to be engaged by cooperating contacts. The engaging surface iSa of contact I9 lies on the face of the insulating block, while contact 20 is provided with outwardly extending ngers 20a which are adapted to engage the igniting unit contact, preferably with a lateral pressure, when the latter is moved to closedcircuit position as will be explained.

The bolt 23 is insulated from the sleeve I8 by an insulating sleeve 24 and Washers 25, 2B and has a threaded portion projecting beyond the sleeve and adapted to receive a nut 21 which is threaded thereon so as to apply pressure to the washer 26 to lock the bolt, contacts and insulation in position on the holding device.

In order to connect the contacts to a source of energy, the end of the bolt projects beyond the nut 21 and has a connector 28 threaded thereto to which is secured a conductor 29 leading to the suitable source of energy. An insulating sleeve 30 covers the coupling, as will be seen in the drawings, to prevent any short-circuiting at that point.

In the form of the invention shown in Figs. l to 3, the holding device is locked in position on the dashboard by means of a tubular locking member 3i of a diam-eter to completely surround the holding device and of a length to extend to a position to engage the back of the dashboard. The locking member has a portion 32 thereof of reduced diameter which is adapted to be threaded on the external threads of the sleeve I6 to move the member 3l along the holding device and draw the holding device into rm engagement with the dashboard or panel.

The igniting unit comprises a sleeve' 33 of insulating material having a reduced projection portion 34 projecting from one end and adapted to have threaded thereto a conducting cap 35 of less diameter than the holding device. The conducting cap extends across the end of the sleeve and has mounted thereon a heating element comprising a helical coil 36 of resistance wire carried within a contact cup 31 and having one end secured thereto. The other end of the coil is connected to a central stud 38 which is insulated from the contact cup and passes through a suitable insulating bushing 39 in the conducting cap. The end of the central stud is headed over as at 40 to lock the contact cup on the conducting cap. rIhe contact cup is insulated from the conducting cap by an insulating washer 4| and is adapted to engage the contacts in the base of the holder when moved to closed-circuit position.

The insulating sleeve 33 for a part of its length extending to the other end thereof is of reduced diameter as at 42 which forms an abutment or stop 43 and has the end thereof threaded to receive a handle 44.

A friction sleeve 45, adapted to slidably nt into the holding device, surrounds the insulating sleeve and has at its forward end an outturned ange 46 for engaging the ilange I2 of the holding device to limit its inward movement into the holding device, and on its other end an inturned flange 41 slidably iitted on the reduced diameter of the insulating sleeve. A spring 48 i5 disposed about the reduced diameter of the sleeve so as to have one end abutting the inturned flange of the friction sleeve, and the other end abutting against the end of the handle which is threaded on the reduced portion of the sleeve.

The friction sleeve is provided with a plurality of lanced-out fingers for engaging the holding device to hold the igniting unit in place thereon.

As shown in Fig. 1, the spring holds the body portion of the igniting unit outwardly on the holding device with the abutment 43 engaging the ilange 41 and permits the same to be moved relative to the friction sleeve when it is desired to move the contact 31 of the igniting unit into engagement with the base contact to close the circuit to the heating element.

According to the present invention, the friction sleeve of the igniting unit, which during operation of the cigar lighter maintains a predeten mined position on the base, is utilized to provide a means to hold the igniting unit in closed-circuit position when manually moved thereto. This may be accomplished in many ways. However, in the illustrated form of the invention, the igniting unit is provided with a pair of slots 54 formed in the insulating sleeve 33, and a pin 5l, having its two ends secured to the friction sleeve, extends through the slot in the body of the igniting unit formed by slots 50. The pin can be of conducting material or not, depending whether it is to be included in the energizing circuit. The portion of the igniting unit which is movable relatively to the sleeve to close the circuit and has a latch 52 thereon in a position to engage the pin and hold the movable portion of the igniting unit in closed-circuit position and is preferably operable to release the pin upon the heating element attaining a desired heat.

As shown in the drawings, this latch comprises a pair of bimetallic arms 53 electrically connected to the inner end of the heating coil by having a portion thereof secured under the headed over portion 40 of the stud 38 and extending into the bore in the insulating sleeve. The arms are positioned in such a manner that they will engage the pin 5I upon movement of the movable portion of the igniting unit into the position wherein the contact 31 engages the contact fingers 20a and completes the circuit from the end of the heating coil through the pin 5| to the friction sleeve 45, and through holding device to ground. The arms are relatively long, and slight movements thereof will operate to release the pin.

As soon as the heating element has attained its predetermined desired heat, the bimetallic arms or ngers will have iiexed and released the pin, whereupon the spring 48 will move the movable portion of the igniting unit into its normal open-circuit position.

With this construction, it will be seen that the latch contacts and cooperating abutment member are carried entirely within the body of the igniting unit and cannot readily be tampered with to destroy the adjustment.

Furthermore, the bimetallic latch member can be properly adjusted to hold the movable part of the igniting unit against the urge of the spring carried by the igniting unit until the heating element has attained its desired heat. With such a balance existing between the spring and latch` both of which are carried entirely by the igniting unit, the igniting unit can be placed on one of several holding devices and operate successfully Without any further adjustments.

If it is desired to provide a means for reclosinf; a circuit after the bimetallio latches have been separated upon being heated, the holding dcvice can have a finger 58y lanced therefrom, as shown in Fig. 3, for engagement with the rim of the conducting cap 35, which may or may notl be of the same diameter as the holding device, when the igniting unit is moved inwardly by manual pressure so that the contact cup 31 engages the portions |9a or 20a of the base contacts.

In this manner, the circuit can be reclosed and maintained closed even though the heat-responsive latches are fiexed into a position in which they will not engage the pin.

In order to indicate when the heating element has attained its desired heat, the conducting cap andcontact cup are provided with apertures 5S opening into the interior of the conducting sleeve so as to permit the light from the incandescent heating element to pass through the igniting unit to a lens Ell which is mounted at the end or the handle and cause it to glow upon the heating element acquiring suiicient incandesoence for use.

Figs. 4 to 7 show a simplified form of the invention in which a tubular holder I is provided to slidably receive an igniting unit which is completely removable therefrom for use. The holding device is provided at its forward end with an outwardly turned Iiange ||2 adapted to engage the front face of a panel or dashboard llt, when the holding device is inserted into an aperture ||4 in the panel.

The back end of the tubular holder is provided with a transversely extending wall H5 having a central aperture through which extends an externally threaded sleeve ||6 having a flange Ill at one end thereof which extends over and is secured to the end wall H5 to lock the sleeve in place.

Positioned' in the base of the holding device is a contact member |23 having outwardly projecting fingers |2a adapted to engage the igniting unit as will be explained.

In order to secure the contact |2 in the holder and electrically connect it to a source of current, a stud |23 passes through the central portion of the contact so that its head |23?) engages the outer surface of the contact. The stud then passes through the sleeve ||6 and is insulated therefrom by an insulating sleeve |24 and a pair of Washers |25 and |26. The washer |25 extends between the contact and the iiange |1 to insulate vthe contact from the holding device, and washer |26 'abuts against the open end of the sleeve i6. The stud is held in position by a nut |21 threaded on the free projecting end thereof and into engagement with the washer |26 to clamp the ccntact and stud in place.

'I'he stud has mounted thereon a connector |23 secured to a conductor |29 leading to a source of energy, the connector being locked in place by a nut |3il which clamps it against the nut 21. Thus, the contact through the stud is connected to one terminal of the source of energy.

When the holding device has been inserted through the aperture in the panel, it is locked in place by a U-shaped stirrup ISI having an aperture in the bow adapted to be positioned over the sleeve ||6 with the free ends of the legs of the U engaging the back of the panel, and a nut ,|32 is threaded on the sleeve H6 to lock the stirrup in position and draw the flange H2 in engagement with the front of the panel.

The igniting unit comprises a sleeve 32 of insulating material having a reduced neck portion |34 at one end thereof, and a trans- A-versely extending wall |35 closing the end thereof so as toform a support for a heating element in the form of a coil |36 of reslstancewire. The coil is mounted in a contact cup |31, and has one end secured thereto and the other end secured to a central stud |38. The contact cup surrounds the heating element and is disposed so that it will engage the fingers IZa of the base contact when the igniting unit is moved to closedcircuit position, as will be explained.

The cup is secured to the end wall of the insulating sleeve by the central stud which is insulated therefrom by a washer |4| The central stud passes through the wall |35 and is headed over as at |40 to lock the heating element and contact cup to the wall.

The other end of sleeve i3d is provided with a reduced portion |42 which forms an abutment |43 thereon. The end of the reduced portion is threaded to receive a handle |44 which, in the preferred form of the invention, is made of a translucent material.

Surrounding the reduced portion of the sleeve is a friction sleeve |45 having at its forward end an outturned flange |46 adapted to engage the flange I2 of the holding device to limit the insertion of the sleeve when the igniting unit is placed on the holding device. The other end of the sleeve is provided with an inturned flange |41 which surrounds the reduced portion of the sleeve as shown in the drawings.

-interposed between the friction sleeve and the body of the igniting unit is a spring |48 which surrounds the reduced portion of the sleeve so as to have one end bearing against the friction sleeve flange |41, and the other end abutting against the end of the handle |44.

To hold the igniting unit on the holding device, the friction sleeve is provided with fingers lanced from the body of the sleeve for engaging the surface of the holding device. This, together with the flange |46, effectively holds the friction sleeve in relatively xed relation with the holding device. The remainder of the igniting unit is slidable relative to the holding device and friction sleeve, and is yieldingly urged into normal position as shown in Fig. 4 wherein the circuit to the heating element is opened.

Upon manual pressure being applied to the handle, the spring will be compressed to permit the igniting unit to be moved into the position shown in Figs. 5 and 6, wherein the contact |31 engages the Contact 2U in the base.

According to the present invention, novel means for holding the igniting unit in this position is provided in which the relatively xed position of the friction sleeve on the holding device is utilized. This is accomplished by providing the insulating sleeve with a pair of diametrically opposed slots |50. An abutment member |5| having its ends secured to the friction sleeve, `as shown in Fig. 4, extends across the body' of the igniting unit. The movable part of the igniting'unit is provided with a detent |52 to' cooperate with the member when the movable portion of the igniting unit is moved into closed-circuit position to hold said portion in that position until the heating element is ready for use.

The latch may be controlled in many ways, but, in the illustrated form of the invention, the latch comprises a pair of bimetallic arms |53 secured under the head |4l` of the central stud to project inwardly into the sleeve and have detents at their `ends to engage the member I5 l In the preferred form of' the inventionthese arms are connected to the end of the heating element and comprise not only a detent but a switch means in the energizing circuit as it completes the circuit for the heating element from the inner end thereof to the member Eel, through the friction sleeve to the holding device and to ground when the movable portion is moved to closed-circuit position.

Upon the heating element attaining its desired usable heat, the arms |53 will flex and being relatively long slight movement thereof will impart suiiicient movement to the detents to release the same from engagement with the member |5l, whereupon the circuit will be opened and the movable position of the igniting unit will move back under the urge of the spring |48 to its normal position wherein the circuit will not be remade automatically.

Should it be desired to provide a means for remaking the circuit immediately, irrespective of the position of the bimetallic arms |53, the igniting unit can be provided, as shown in Fig. 7, with a conducting cap |56, secured to the end of the sleeve, and from which the contact cup is insulated by a washer |51.

The holding device is then provided with a contact |53 which engages the conducting cap |56 when the igniting unit is moved to closed-circuit position. This will enable a circuit to be completed to the heating element and relight to be obtained immediately upon the heating element being moved to closed-circuit position and manually held there.

In order to indicate that the heating element has attained its desired usable heat, the end wall of the sleeve |33 or cap |56 and the contact cup |37 are provided with apertures |59 opening into the hollow of the sleeve so that light from the incandescent heating element can pass through the sleeve to the translucent handle, which will glow upon the heating element attaining a predetermined desired heat.

Various features illustrated herein are described and claimed in my copending applications Serial No. 59,488, filed January 17, 1936, and Serial No. 360,714, iiled October 11, 1940.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

I claim:

l. In an electric cigar lighter, a holding device; an igniting unit having a heating element secured thereon, said igniting unit being carried by the holding device and completely removable therefrom for use, said igniting unit having a friction sleeve therearound comprising stop means for engaging the holding device to position and hold the igniting unit on the holding device, and a second hollow portion movably mounted relative to the sleeve; yielding means interposed between the friction sleeve and said relatively movable hollow portion of the igniting unit for normally urging the said portion of the igniting unit into a position in which a circuit through the heating element is open and yieldable upon manual pressure on the said portion of the igniting unit whereby the portion of the igniting unit can be moved to close the circuit to the heating element; contact means in the holding device,

said heating element being mounted on the said movable portion of the igniting unit for relative movement therewith and having a similarly movable contact for engaging the contact means on the holding device when the movable portion is in said closed-circuit position; means on the interior of the friction sleeve extending into said hollow portion through an aperture therein and means within the movable hollow portion of the igniting unit, the latter means being impositively engageable with said means on the sleeve for holding the movable portion of the igniting unit in closed-circuit position against the urging of the yielding means; and heat-controlled means in heat-receiving relation with the heating ele- Cil ment for automatically releasing said means on the friction sleeve from said means within the movable portion of the igniting unit upon the heating element attaining a predetermined desired heat whereby the yielding means moves the relatively movable hollow portion of the igniting unit into open-circuit position.

2. In an electric cigar lighter, a holding device; an igniting unit carried by the holding device and completely removable therefrom for use, said igniting unit having a hollow plug-like body, and a relatively movable sleeve surrounding the same and comprising stop means for engaging the holding device to position the sleeve relative thereto; a heating element secured to the pluglike body and movable therewith relative to said sleeve; yielding means interposed between the plug-like body and the sleeve for normally urglng the plug-like body to a predetermined position with respect to the sleeve; means including a contact on the holder and a contact on the plug-like body and movable therewith for closing a circuit to the heating element, said contacts engaging each other upon movement of the pluglike body away from said predetermined position relative to the sleeve and against the urge of the yielding means; means carried on the interior of the sleeve extending into said plug-like body through an aperture therein; and means within the hollow plug-like body for engagement with said inwardly extending means on the sleeve and cooperating therewith to hold the contacts in closed-circuit position; and thermostatic means for releasing said last-named means upon the heating element attaining its predetermined desired heat, whereupon the plug-like member is moved by said yielding means to said predetermined position with respect to the sleeve to separate the contacts and open the circuit.

3. In a cigar lighter, a holding device; an igniting unit having a heating element movable on the holding device and completely removable therefrom for use, said igniting unit comprising a hollow movable portion and a friction sleeve surrounding said movable portion and engaging said holding device; yielding means interposed between the friction sleeve and movable portion for maintaining the movable portion in a predetermined open-circuit position; means for closing the circuit to the heating element, including contact means mounted in the base of the holding device, and cooperable contact means carried by the movable member, engageable with the contact means on the holding device upon movement of the movable member out of the predetermined position; means within the hollow movable member and means on the interior of the friction sleeve extending into said hollow movable member through an aperture therein and engageable with said means within the hollow movable member for holding the movable member in a predetermined circuit-closing position with respect to the sleeve wherein the contact means on the holding device and the cooperable contact means on the hollow movable member are in engagement, said engageable means .being heat-responsive and automatically releasingy its engagementupon the heating element attaining its desired heat, 'whereupon said yielding means moves said hollow movable member to its predetermined open-circuit position to open 'the circuit; Yand cooperatingv contact means on said igniting unit .and vholding device maintaining the heating `element circuit closed independently of said heat-responsive means upon holding the movable member in closed-circuit position by manual pressure.

4. In a cigar lighter, a holding device; an igniting unit carried by the holding device and completely removable therefrom for use, said igniting unit comprising a plug-like body and a sleeve surrounding the same, said sleeve engaging the holding device and having means thereon for holding it in a predetermined position with respect thereto; a heating element secured to the plug-like body; yielding means interposed between the sleeve and plug-likeL body for normally urging the plug-like body into predetermined relation with the sleeve; means for closing the circuit to the heating element upon movement of the plug-like body out of said predetermined position against the urge of the yielding means, said body having a transversely extending slot; an abutment member secured to the sleeve and extending across the plug through the slot; detent means on the plug for engaging the abutment member when the plug-like member is moved to closed-circuit position; and heat-controlled means for releasing the detent when the heating element has attained its desired usable heat, whereupon the yielding means moves the plug-like member into open-circuit position.

5. In a cigar lighter, a holding device having a contact therein; an ignitingy unit carried by the holding device and completely removable therefrom for use; said igniting unit comprising a hollow plug-like body and a sleeve surrounding a part thereof and movable relatively thereto, said sleeve engaging the holding device and having means thereon for maintaining it in a predetermined position with respect thereto when in position thereon; a heating element secured to the plug-like body; yielding means interposed between the sleeve and plug-like body for normally urging the plug-like body into a predetermined position with respect to the sleeve; contact means carried by the plug-like body for engaging the contact of the holding device to close a circuit to the heating element upon movement of the plug-like body out of said predetermined position and against the urge of said yielding means; an abutment secured to the sleeve and extending into the hollow body through a cutaway portion in a wall thereof, the cutaway portion being elongate as compared with said abutment to permit motion of said body relative to said sleeve in circuit-closing direction; and detent means secured to the heating element and carried internally by the hollow plug for engaging the inwardly extending abutment member incident to movement of the plug-like member into closed-circuit position to hold the contacts in engagement, said detent means comprising bimetallic arms secured to the heating element in heat-receiving relation therewith and flexing upon the heating elementattaining the desired usable heat to release the abutment whereupon the yielding means moves the pluglike member and contact carried thereby into open-circuit position.

6. In a cigar lighter, a holding device; an

igniting unit carried bythe holding device and completely removable `therefrom for use, said igniting i unit comprising a hollow plug-'lilrebody and a frictionsleeve surrounding a part of said body, said sleeve Vengaging the holding device and including positive means for'holding it stationary with respect thereto whenin place thereon; a heating element carried by the yplug-like body, 'the latter `being movable Atogether with said heating element relative to said sleeve; yielding means interposed between the sleeve and plug-like body for normally urging the plug-like body into predetermined relation with the sleeve; means carried by said movable plug-like body and means carried by the holding device cooperating therewith for closing the circuit to the heating element incident to movement of the plug-like body out of said predetermined position against the urge of the yielding means; means for holding said plug in said lclosed-circuit position comprising a detent carried within the hollow plug-like member; an abutment secured to the interior of said sleeve and extending through an aperture in the wall of said plug-like body to the interior thereof, and into the path oi movement' of the detent for engagement thereby incident to movement of the plug-like member to closed-circuit position; and heat-controlled means for releasing said detent upon the heating element reaching its desired usable heat, whereupon the yielding means moves the pluglike member into open-circuit position.

'l'. An igniting unit for a cigar lighter adapted to be removably supported by a holding device having a contact therein, comprising a hollow movable portion having a heating element thereon and a friction sleeve surrounding a part of the removable portion; yielding means interposed between the friction sleeve and movable portion for urging the movable portion into a predetermined position with respect to the friction sleeve; contact means on the movable portion for cooperating with the contact in the holding device to close a circuit to the heating element upon movement of said movable portion away from said predetermined position against the urging of said yielding means; latch means carried within the hollow movable portion; an abutment secured to the friction sleeve and extending through an elongate cutaway portion in a wall of said hollow portion for engagement by the latch means when the movable portion is moved with respect to the friction sleeve to the position in which the contact carried by the movable portion will engage the contact on the holding device, said abutment and latch means holding the movable portion against the urge of the yielding means, said cutaway portion being elongated in the direction of said motion to permit such motion of the movable member relative to said abutment; and heat-responsive means for releasing the latch means when the heating element attains a predetermined temperature.

8. An igniting unit for a cigar lighter adapted to be removably supported by a holding device having a contact therein, said igniting unit comprising a plug-like body and a sleeve surrounding the same for engaging the holding device, said sleeve having means thereon for holding it in a predetermined position relative to said holding device; a heating element secured to the plug-like body; yielding means interposed between the sleeve and plug-like body for normally urging the latter into a predetermined position relative to the sleeve; contact means on the plug-like member for cooperation with the contact on the holding device to close the circuit to the heating element upon movement of the pluglike body out of said predetermined position against the urging of the yielding means, said body having a transversely extending slot; an abutment member secured to the sleeve and extending across the plug through the slot; a detent means on the plug for engaging the abutment member when the plug-like member is moved to closed-circuit position; and heat-controlled means for releasing the detent when the heating element has attained its desired usable heat, whereupon the yielding means moves the plug-like member relative to said sleeve into open-circuit position.

ARTHUR A. JOHNSON.