US 2666480 A
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Description (OCR text may contain errors)
Jan. 19, 1954 R. E. PETERSON 2,666,480
HAND TORCH AND IGNITER FOR USE WITH LOW BOILING POINT FUEL 2 Sheets-Sheet 1 Filed Feb. 24, 1947 N U f m m. T W. v d w A lay Aw 4 ww an m m IZNQ Q Q Q w Nu ww Mm W lllzl ,4 rme/vEs s 1954 R. E. PETERSON HAND TORCH AND IGNITER FOR USE WITH LOW BOILING POINT FUEL 2 Sheets-Sheet 2 Filed Feb. 24, 1947 A rwe/ya s Patented Jan. 19, 1954 HAND TORCH AND IGNITER FOR USE WITH LOW BOILING POINT FUEL Robert E. Peterson, New York, N. Y.,assignor to Repeter Products, 1110., Long Island City, N. Y., a corporation of New York Application February 24, 1947, Serial No. 730,488
This invention relates to torches, and mor particularly to a portable blow torch, characterized by a self-contained igniting device and adapted to burn in gaseous form a low boiling liquid fuel.
Portable blow torches of the type commonly and frequently used by plumbers, electricians, mechanics and the like are, for the most part, the well-known pressure type which burn gasoline or kerosene. Such torches, while satisfactory for heating soldering irons, or melting fusible materials in readily accessible locations, are nevertheless of relatively limited application. 'As it is unsafe for a workman to carry any type of torch while it is ignited, this common type of blow torch is characterized by very material difculties in use, by reason of the time and difficulty encountered in initially igniting or .reigniting it. As is well known, such a torch must be primed or preheated before it will burn vigorously and at the high temperatures necessary. Thus, for example, if a painter finds it necessary to mount a ladder to get at the paint he wishes to burn, he cannot safely carry the ignited torch up the ladder with him, but must attend to the ignition of the torch while sometimes precariously bal-z anced on a ladder top. Then too, such torches periodically require pumping to restore the pressure in the fuel tank, with the result that pressure failure, with resultant lessening of the flame and lowering of its temperature, may occur, and indeed frequently does occur at a critical time.
Then too, such gasoline blow torches areusually relatively heavy and cumbersome, must be frequently cleaned, are troublesome to refill, and occasion the waste of a substantial amount'of time and fuel for both initial ignition and reignition. Also, such torches, because of inherent incapacities, cannot provide a flame of sufficient heat intensity and shape for certain types of jobs. 1
It is accordingly among the objects of my invention to provide a simple, relatively inexpensive and light weight but rugged blow torch, which overcomes the above disadvantages, in addition to others, in a simple and practical manner. Other objects will be in part apparent, and in part pointed out hereinafter.
In accordance with one form of my invention, I provide a light-weight container for a low boil- 2 automatic ignition apparatus which ignites the air-fuel mixture automatically when the valve mechanism is opened to permit the passage of gaseous fuel from the fuel tank to the mixing chamber. More particularly, the valve mechanism may, in accordance with my herein disclosed invention, comprise a flexible tube formed of non-corrosive material which, when the torch is out of use, is automatically pinched closed,
thus to shut off the flow of gas, but which, by reason of its resilience and the gas pressure, readily opens to permit the flow of gas when the torch trigger is depressed.
In the drawing, wherein I have shown several forms of my invention,
Figure 1 is a sectional elevation of one form of my torch detachably secured to a fragmentary portion of a fuel container;
Figure 2 is a sectional elevation of another form of the torch; 1
Figure 2a is a fragmentary sectional elevation taken along the line 2a2a of Figure 2.
ing liquid fuel, which may be detachably secured to a pistol-like torch, provided with manually controllable valve mechanism and adjustable means for providing variable amounts of primary air for adjusting the air fuel ratio to its most efficient value.
Also included in the torch is an Figure 3 is a fragmentary top plan portion of the igniting device.
Referring first to Figure 1, the torch, which is generally'indicated at It, comprises a preferably two-piece body casting H or the like, having a neck l2 for detachable connection to a container [3, a hand grip [4, a trigger I5, a metering valve, generally indicated at [6, a mixing chamber Ill, and an ignition device generally indicated at I8. Thus, when the trigger I5 is depressed, the valve mechanism to be described hereinafter is opened to permit the fiow of inflammable gas from container i3 to mixing chamber ll, wherein the gas is mixed with primary air, and from which the mixture flows for ignition by the device 13.
Container I3 is of a type adapted to contain a low boiling point liquified gas, such as propane or butane, or a mixture of the two, and should accordingly be sufficiently sturdy to withstand the pressure of vaporization of such fuel or fuel mixture. To the top of the container is swaged or otherwise secured an exteriorly threaded neck t9 having an annular rabbet formed in the upper end thereof to receive a flanged bushing 20. This bushing, in turn, has secured therewithin a flexible seal or stopper 2! which, for example, may be formed of neoprene or any other suitable material which is not affected, or rather which is not subject to attack by the liquid fuel in the ting and the top of the bore within the body H casting. Also threaded into the. tp=0f the pistol body neck [2 is a gland 28, sealed as byvapacka ing ring 29, and having secured therewithin a metal tube 30, which communicates byway of bore 26 with the interior of containerI-S.
Pistol body II is hollow, so as to provide "a" chamber 3| within which the top of gland: 28 and tube 30 are disposed. Within this chamber is disposed a bracket 32, which is preferablyformed of a phenolic condensation compound, or other suitable dielectric material, and which :may: be
secured' to the side or" the pistol casingin any suitable manner, as, for example, by screws 33. Bra'ck'et SZ is suitably drilled to receive afiexible tube "34, the lower end of which is attached'sto the upper eridof tube 32, and 'the'upperend 34a efwhich is attached to "the right-hand end of a tube 35. "rupees is also' form-ed-oi aflexible material, e.'- g. neoprene, or other material not subject-to attack'by the gas flowing therethrough. =The hole extending-through bracket 32 is'just large enough to receive tube34 and adequately support it against movement withinchamber' fl.
Tube 35'which; as noted-above, is connected to the upper end of tube 34, is preferably of metal, andextends through a wall 36' of the pistol casing, and into'a 'jet 3'I which isscrewed into this wall. The orifice 33 of jet 31 opens into mixing chamber H.
The flow of gas through tube 34'' is controlled by'both trigger l and valve 16, as will now be described. "Trigger I 5inc11ides' a body' portion -39,-'-a-'downwardly extending finger engageable portion 4a, and a pilot 4| received respectively "within a-guide 42,- a recess 43, and another guide 44* formed in pistol casting H. A spring"45 is "disposed within the pistol "casting and has one end seated-against an inner portion of grip 14,
and the other end bearing against the right-hand *side of trigger body39, so as constantly to bias "trigger-1'5 to the left, .i.-e. to closed position. Attached to one side of trigger body 39, as by pins-46; is a plunger 41, the free end 41a of which extends'into a hole 32a formed-in-bracket 32,.and
"communicating with the vertical hole therein within which the center section of tube 34 is disposed. This end 4711. of plunger 47 is adapted to bear-against tube 34 with sufiicient pressure, :by virtue of spring 45, as to pinch tube 34 hard :enough to tightly close the passage therethrough,
even against the substantial'pressure' of the'gas gincontainer 13,. Thus it maybe seen' that when it isdesired touse the torch,'trigger i5 is pressed "into pistol handle I4, i. e; is-moved to the right,
as viewed in- Figure 1, thus to relieve thepressure of-"plunger end 41a on tube 34, permitting the tubetoopen and gas to flow therethrough.
To'meter the flow of gas through tube 34, valve 16' is provided. This valve comprises a thumb piece 48, secured to the end of a shaft 49, threadably received within a hole 56 in the upper portion of casting II, and having secured to its end a stem-'5! having a rounded end 52 extending into a ho1e53'iormed in theupper portion of bracket 32. This hole communicates with the hole with- "in which tube is disposed-so that when thumb 4 piece 48 is rotated in one direction, stem end 52 can be forced against tube 34 to pinch the tube as much as desired. Thus the flow of gas through the tube can be metered, as desired, or when it is desired to store the torch between periods of :use,;tube 34 may-be completely closed by valve it, "thus providing an adequate factor of safety over and above the closing action of plunger 4?.
Mixing chamber I1 is formed by a fitting 54 m ofheatrinsulating material, which may be thread- ;Jably attached to the boss 55 of the pistol casting II, which carries jet 31. Fitting 54 is tapered r as at-54wandis'provided with one or more open- "in'gs* 56,",and has rotatably mounted therein a sleeve 51; similarly-provided with holes 58. Thus t-sleevezisl may be rotated relative to fitting 54 to bring into complete or partial registery holes 58 and "56, respectively, to provide the desired amount of primary air' for mixture with the gas etoztheid'esired' a-ir'fuelrationwithinmixingchambe]: 51. It followsthatjet 3.1;fitting lilii'andsleeve i""l.-;comprise;' in 'efiect; a 'venturi. The free endiof 'rfitting 5'4:detachablyreceives a nozzle: or burning chamber, generally indicated at 59, havingi-ho'les 1 for admission:;of=sec.ondary air. Nozzletiis supports the'ignitiontdevice |8,as shown. 'iIf de- .sired,ynozzle"59 maybeprovided with one or more fins 6|,- :for the dissipation of'heat, and'also may carry an end :cap $2 or :the like, of greater diam- Keter' than the nozzle end, for: regulation of the ishapeof the ifiame, and-.alsofor drawing insup- :plementary air'to assist the-cor'nbustion of the'air- 'fuelmixture.
The structural aspects. of thentorch. hereinbeforedescribedare' such'as readily lend themselves to fabrication from: light-weight: mate- .lllflilSj'SO that:.the'wfeight of :the torch and-tank together is materially less than that of the conrventional. blow torch, thus-greatly facilitating the tusestof-ithe torch; and. -indeed.making-.-use there- Joli-P05511016 under. conditions which would 'preclude'theuse of agasoline-blow torchof the well- :known type. Thus, shown, thembody of the rtorch vmay comprise a single casting whichmay 'beclosed "on one side and open'on the other-to rzpi'ovide=aaccessrto' the interior 'o'f the torch :for the-installation therein of the parts heretofore and hereinafter described, the. opengside conveniently beingclosed by a cover, plate (not e'shown) a It should also be noted that the nozzle -59".:is releasably mounted on the. end oifitting w54,-where lit is Zheld'in proper operative position rby'a spring clipfit; fastened as by'a rivet 64 to :ithe pistolcasting. Thus it may be seen that different nozzle sizes a and shapes 'may' readily be provided, :thereby to. control within limits the size and shape of the .flame.
As':noted :hereinberore, thev fuel. for the torch :.:may' -be fliilDW-I boilingxpoint fuel which, because of its high vapor pressure, maintains itself inliqauid formwithinithe container 43. lhave found it advantageous to employ pure 'pI'Opa-Yle liquid :form, *although any other uliquid. fuel-having proper-ties :similarzto those ofvpropane may be 65 .used. .Thusany fuel having a boiling pointof the'nrder'aof -40? .may-be used, as such low boiling point fuels create satisfactory pressures which do znotbecome-dangerously high in temperatures of 0:F; 'to l30F. For example, pro 79fpaneboils at-14l.5'F. andat 0 F. has a vapor pressure of3f7.8 pounds per square inch, and at 130 FLhas a vapor pressure of 274.5 pounds per 1 square:..inch. It'will be appre'ciatedpof course, that this; higher pressure doesin'ot have any occupational hazards attendant thereto; as modern steel containers are designed to withstand such pressures with a factor of safety in excess of five. Also, from the foregoing description of container l3, it will be readily apparent that it an easy matter for the user of the torch to carry with him one or more extra ,fuel containers which may be readily attached to the torch when the fuel supply in the container in use becomes exhausted. Also, by reason of the nature of the seal or stopper 2|, the container in use may, if desired, be disconnected from the torch without danger of escape of gaseous fuel therefrom, as the spring clip or ring 23 tightly closes the neck 'of the stopper when the needle 25,15 withdrawn.-
As hereinbefore noted, ignition of conventional gasoline blow torches has certain disadvantages, To the end of overcoming these disadvantages, I have provided the ignition system .now to be described. The igniter I8 may comprise a flanged bushing 65, having secured therewithin a dielectric 56, the bushing being thread= able into nozzle 59 or frictionally held therein,
as desired. The dielectric plug 86 carries a conductor pin 61, to which is attached one end of a resistance element or coiled wire 58, the other end of which is grounded, as to the bushing 65.
'To pin 6'! is fastened one end of a conductor 63,
the other end of which is attached to a binding post 10, mounted on bracket 32. Electrically connected to this binding post is a resilient spring is :pistol casting and is carried down through the handle l4 thereof, where it is connected to a fixture which supports a contact Tl. This contact 11 is adapted to be engaged by a contact 18 of a dry cell 19 which is conveniently removably disposed within the bottom of torch handle 14, the other side of the battery being grounded in' customary manner. Thus it follows that when switch contact 52 engages switch arm 13, a
circuit to the resistance element 58 is completed,
causing the element or wire to glow with sufficient heat to ignite the gaseous mixture flowing through the nozzle.
Energization of the heater element, es which,
incidentally, may advantageously be a platinum wire of proper diameter, is automatically effected upon depression of trigger l5. To this end, trigger body 39 has pivotally fastened thereto one transverse end 88 of a U-shaped link which is biased counterclockwise by a link 85 which is biased counterclockwise by a link 82. This U- shaped link 8! together with its other transverse end 83, extends from trigger body 39 into a lon gitudinal groove 84 molded in bracket 32 in such manner that the link end 83 rides along the bottom 85 of the groove, being held thereagainst by spring 82. When trigger I5 is in the position shown, wherein tube as is pinched closed, link end 83 lies to the left of a pawl 88, pivotally mounted on bracket 32, and spring-biased counterclockwise. It may now be seen that when trigger l5 is depressed to permit gas to flow through tube 35, link end 83 rides up pawl 85 and ultimately engages the resilient switch arm 1!, forcing this arm upwardly to engage its contact 12 with the other switch arm 13, thus to close the circuit to heater element 68. It should be 'noted, however, that before this circuit is closed,
tube 34 is released so that gas may flow therethrough, thus to assure the presence of a gaseous mixture in the vicinity of the heater element when the circuit thereto is closed. As the trigger i5 is further depressed, link end 33 finally rides over the top of pawl 86, and the link spring 82 swings the link and accordingly the end 83 downwardly against the bottom 85 of groove 84, so that the switch contact 12 can move away from switch arm 13 and break the circuit to the heater element. It follows, of course, that when trigger it is released, link end 83 underrides pawl 35, swinging it clockwise as it rides thereunder to its position shown. Thus the heater element E8 is energized for a brief period of time only, sufiicient, however, to ignite the gaseous mixture within the nozzle.
While a liquified gas such as I have hereinbefore described is usually free of foreign particles, I have nevertheless found it desirable to provide one or more filters between the gas container and the torch jet to preclude clogging of any of the gas passages within the torch, particularly in vi w of the fact that these passages are of small diameter of the order of .013 of an inch. Thus I have provided a filter wafer 87, which may be formed of a suitable ceramic material, and is interposed between fitting 24 and gland 28 at the entrance to the gas passageway within the torch. At the exit end of the gas passageway, I provide another filter wafer 38 which may be conveniently disposed within wall 36 of the casting at the base of the bore, which receives the nipple end of jet 37. Thus it may be seen that any foreign particles which might be forced from container l3 into the torch are stopped by filter 81, filter 88 precluding the passage of any foreign particle that might pass filter 8? into the minute orifice 38 of'jet 31.
Referring now to Figure 2, wherein I have shown another form of my invention, the torch is generally indicated at Hit, and, as in the case of torch I i includes a body casting lili having a neck 02 by which the torch is detachably fastened, as by a bayonet joint, generally indicated at 103, to container I 3. Torch Hill also includes a handle or grip ltd, within which is slidably mounted atrigger me. A metering valve, gen erally indicated at I96, is disposed in the top of the torch casing to meter the flow of gas into a mixing chamber W1, wherein the gas is mixed with air, and from which the mixture flows for ignition by an igniting device, generally indicated at I08.
In the present instance, container 13 has brazed, or otherwise secured to the top thereof, a neck H39 in which are mounted pins l H) formme one element of the bayonet joint Hi3. Neck Hi9 also has disposed therein a stopper or seal l H which is tightly secured in place by a flanged bushing H2 press-fitted into the top of neck N19.
The entrant end of the neck is frusto-conical, as
needle M being generally similar to fitting 24 and need1e 25 of Figure 1. Thus when container I 3 is attached to the torch casing, the fitting needle l 14 enters the aforementionedhole in seal III, spreading the .hole' sufiiciently, andaccordneedle and the seal. As needle H4 isprovided with an axial hole II5, communication is established with the interior of container I3.
The top'of fitting I I3 is sealed relative to the casing IOI, preferably by a sealing ring H5,
which conveniently forms a space-within which .is disposed a filter IIl, between fitting I l3 and a small, transversechannel I18, formed in casing IOI. This channel communicates with cne'end of a small pipe M9,. the other end of which is secured to a resilient tube- I20, the dotted line portions of the pipe and tube being disposed within a chamber (not shown) formed within casing Il. Tube I is threaded through a hole cured to a small pipe I22, which is mounted in and extends through a .hole in the casing and communicates with arr-opening 123 formed there- .in. This opening is threaded, as shown, to receive the nipple end of a jet I24, a filter I23abeing disposed between the'inner end of the-jet and the bottom of the hole I23. Thus it may now be vit is depressed. The triggeris constantly biased to the left of the drawingas by a spring, I28, one end of which bears against the torch handle I04 within a recess I20 formed therein, andv the other end of which bears against the right-hand end of trigger'portion I25. Trigger portion I also carries a transversely extending -pinwhich acts in the manner'of plunger 4'! (Figure 1) to pinch tube I20 closed when the trigger Metering is in the position shownin Figure 2. valve I05 includes a stem .I3I which maybe axially: adjusted, as" desired, with respect to tube I20, to control the side of the opening therein in the same manner, and for the same-purpose as hereinbefore described with respect totube 34 and valve stem 5| (Figure. l). Thusit follows that tube I20 may be held open or closed at will by'manipulation of trigger I05, and the flowof :gas through the tube maybe metered or controlled as desired by, manipulation ofrmeter-ing valve I05.
It. might be well to .note at this point thatcasing I 0!. comprises a pair of castings I Ola and I Illib (Figure 2a) which are so formed that, when secured together, they .form the chambers hereinbefore referred. to, as well as a channel in which. tube 120 is disposed, thus adequately to support the tube against the pressure of pin I30 when trigger I05 is released, to pinch off the tube. Also, casting IOIb is so formed as to receive a filler .l0Ic, the inner. vertical surface of which comprisesa guide or supporting surface for trigger portion 125.
,The. ignition systemf for...the. torch. .shownl..in Figure '2 is ofsthe hot spark type, wherein a. sucin the casing; with its upper end 9200, being-disposed within a chamber i2I formed in the upper portion of the casing. This end of the tube is socession, of sparks is rapidly generated .upondepression ofv trigger I05 by a. condenser inductor system. Thus the handle I04 of the torch-is hollowed to receivea dry cell I32 which comprises the power source for a circuitincluding leads I33 and I34, a condenser 35, an inductor 136, a switch generally indicated at I51, aspark plug or the like, generally indicated at I38, lo-
cated in the end of nozzle. 59 and spring clip 53. .This spark plug or spark gap I33 is connectedas by a beryllium resilient conductor I39 to the inductor 536 sothat when the contactsof switch I31 are closed, in a manner that will be described, a spark is created to ignite the combustible air and gas mixture flowing through nozzle 59.
Switch I3! is successively and rapidly closed to cause .theproduction of a rapid succession of sparks by plug I38 by the mechanism now to be described. Trigger slide portion I25 has secured thereto a pin I40 which forms an anchor for one end of a spring MI, the other end of which is fastened to a pin I42 secured to and projecting from a rack 143. This rack includes a shoulder I44 which normally rests against the. end of a pawl =I45 which is spring-biased into its holding position by a leaf spring I46. The underside of pawl I45 is provided with a cam surface Iii! adapted to cooperate with a rise I48 formed in the left-hand end of trigger slide I25. It may now be seen that when trigger I05 isdepressed, i. e. is drawn into handle I04, slide I25 ismoved to the right, as viewed in. Figure 2, against the pressure of spring I28. This, of course, tensions spring I4I, but does not move rack I43, inasmuch as the rack is held stationary by pawl I45. However, when carn I41 of pawl I45 is engaged by risev 1480f trigger slide I25, pawl M5 is swung clockwise against spring M6 so that as trigger slide I25 continues to move to the right, thepawl is swung clear of shoulder I44 on rack "E43. When this occurs, the rack is suddenly and rapidly jerked to the right. This abrupt and rapid movement of rack I43 rapidly closes and opens switch I31 to efiect the repeated generation of sparks in the following manner.
Rack l lssmeshes with pinion I49 which is secured to a pin I50 (see Figure 3) rotatably .mounted in the torch housing. Keyed to this pin I50 is a clutch element I5I which rotates with the pin but isslidable axially thereof, this element I5! being constantly biased into .engagement with complementary clutch formations in a ratchet wheel I52 by a leaf spring l53.
This ratchet wheel is positioned to ratchet over and accordingly intermittently engage and depressa lug I54 carried by the outer end of the movable arm I3'Ia, of. switchv I31, thus to force this arm intermittentlyinto engagement with the otherv arm i3lb of the switch, to close. the switch. It accordingly follows that when rack I43 is abruptly jerked to the right, as hereinbefore described, pinion I 45, and accordingly pin I50, are rapidly rotated, and through the interengagement of the clutch elements described, the teeth on ratchet. I52 are rapidly moved in a clockwise direction, as viewed in Figure 2, alternately to close and open switch I31 and accordingly effect the production of the succession of sparks referred to. Thus, reliance is not placed on the production of but a single spark to ignite the combustible gas mixture flowing through nozzle 59.
QWhen trigger I05. isreleased rack 153, of course, moves, to the left and consequently r0- 9 tates pinion I49 counterclockwise. This. however, does not effect counterclockwise rotation of ratchet I52, as clutch element ll merely overrides its complementary element carried in or on ratchet I52, thus precluding the production of sparks in plug 138 upon release ofthe torch trigger. To preclude any possibility of the production of sparks at this time, ratchet wheel I52 and lug I54 are so formed that the lug precludes counterclockwise rotation of the ratchet.
It may now be seen that in my improved torch, structural simplicity and operating efliciency are judiciously combined in a manner that attains the several objects hereinbefore set forth in a thoroughly practical manner.
As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth without departing from the scope thereof, it being understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative only and not in a limiting sense.
1. In apparatus of the character described for burning a low boiling point fuel, the combination of, a container adapted to receive and hold a low boiling liquefied fuel which is maintained in liquid form in said container by reason of its own vapor pressure, a body member having fuel inlet and outlet openings the former of which is connected to said container, said container being outside of said body member, means forming a fuel passageway within said body member between said openings, a spring-biased member 'engageable with said fuel passageway means normally closing said passageway to block the fiow of fuel therethrough, said body member including a hand grip, a manually operable member carried by the hand grip and associated with said body member and with said spring-biased member and operable to move said spring-biased member to open said fuel passageway so that fuel can flow therethrough, a carbureting device in communication with said outlet opening, means forming an air supply communicating with said carbureting device, means forming a mixing chamber on the discharge side of said carbureting device, means forming a burner chamber communicating with said mixing chamber, an igniting mechanism including an igniting member operatively associated with said burner chamber whereby the air-fuel mixture within the burner chamber may be ignited. and means ineluding a transmission system extending from said manually operable member to said igniting mechanism for actuating said mechanism, whereby when said manually operable member is operated said spring biased member is moved out of operative position with respect to said fuel passageway means to permit the latter to open and said igniting member is operated to ignite the air-fuel mixture, further movement of the said manually operable member interrupting the operation of the said igniting memher.
2. Apparatus according to claim 1, wherein said transmission system includes a delay device operatively associated with said manually operable member and said igniting member whereby when said manually operable member is operated said passageway is first opened and thereafter said igniting member is operated to ignite the air-fuel mixture, further operation of the manually'operable member interrupting the operation of the igniting member.
3. Apparatus according to claim 1, wherein said igniting mechanism includes an electrically energizable member, a switch and a battery, said energizable member being disposed in said burner chamber, said switch being disposed in said body member, and said battery being disposed in said hand grip.
ROBERT E. PETERSON.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 899,181 McIntyre Sept. 22, 1908 1,364,972 Andersone et al. Jan. 11, 1921 1,463,518 Thomas July 31, 1923 1,530,914 Roden Mar. 24, 1925 1,617,399 Kress Feb. 15, 1927 1,814,068 White et al. Jan. 14, 1931 1,822,356 McCartney Sept. 8, 1931 1,879,631 Mott Sept. 27, 1932 1,895,032 Fisher Jan. 24, 1933 1,970,237 Kramer Aug. 14, 1934 2,064,535 Greenfield et a1. Dec. 15, 1936 2,482,794 Peterson Sept. 27, 1949 FOREIGN PATENTS Number Country Date 524,969 France May 25, 1921 41,439 Denmark Dec. 28, 1929