US2610679A

US2610679A - Safety control and ignition apparatus for gaseous fuel burners

Info

Publication number: US2610679A
Application number: US4318A
Authority: US
Inventors: Weber Victor; William J Russell
Original assignee: Robertshaw Fulton Controls Co
Current assignee: Robertshaw Controls Co
Priority date: 1948-01-26
Filing date: 1948-01-26
Publication date: 1952-09-16
Anticipated expiration: 1969-09-16

Description

Sept. 16, 1952 v. WEBER rrrAL 2,610,679

SAFETY CONTROL AND IGNITION APPARATUS FOR GASEOUS FUEL BURNERS Filed Jan. 26, 1948 INVENTORJ. VIC TOR Weaae Wanna J. Rea-$1.. BY

H 7' TORNE Y.

Patented Sept. 16, .1952

wrSAFE'IYY CONTROL AND IGNITION APPARA- r ,TUS. FOR GASEOUS FUEL 'BURNERS Victor Weber, Greensburg, and William J. Russell,

Jeannette; Pa.,' assignors to Robertshaw-Fulton Controls'C'ompany, Youngwood; Pa.,- a corporaztionsot Delaware e Application lanuary 26, 1948,lSerial"No.-r4,318

=1 "lThis; invention relates "to safety contiol and ignition lapparatus forggaseous iueliburners' and,

:more particularly; to electrically, operatedappar -ratusr for oven burners independent "of commercial-currentsupi lies. I

'L'Incoperiding vapizilication of Charles K. 'Strobel Let vaL Serial"No1*6201320ii1ed'"October' 4, 1945-, t-andtassigned to applicant's .as'sighee there is disjclosed' ainash tube or "single point oven ignition system embodying a" thermoelectric safety device. Tithe: system is, placed in operation by manipulaition'ofiith knob. of an ovengascock which may include a thermostaticdevice. forcontrol of'oven temperatures. In the copendin application the rotary motionnofthe knbbis madezuse'of during the starting period to" operate a" "pull-wire arrangement-by wlhich 'a'ltherma'l timing device isypo'sition'ed to determine; such period.

.An object. of thepresent invention is to render such apparatus more useful by eliminating objectionable torque "due to the, pull-wire arrangement.

Another object 'of the invention isto'i-insure positive operation 'of' the' apparatus whenever a startingperiod is initiated.

Another objector the invention is toe'limin'ate undesirable i forces tending to' disrupt -normal tun'c'tioningfof the control.

Another-object or the invention is to' simplify the mechanism and incidentally; to improvefithe operation .of theitfflashetube ignition portion of the apparatus.

:..Another objectoftheinvention is ito locate yariousjrzarts"of: .the apparatus in low ambient temperature loads; to lengthen the useful life and improve the general performance.

Other objects and advantages .will become 'apparent f'from' the" ioliowingidescription taken in connection with theaccompan'ying Ldrawing,

wherein: I

Fig? I is agener'ally'schematic plan view, shown 'partly in section, o1' a safety control and ignition apparatus forfan oven burner embodying thefmventionrand Fig'JTZ'is airont elevation or a'por'tion of the apparatus shownin Fig; 1. 'Z'Rferring more i particularly .to the drawing, the saf'etycontrol andign'ition apparatus is shown conjunction with a cooking range having the usual oven burner fill and top pilot burner l2 located remotely .irom the oven burnerll 0. As is customaryiinn ap-bliancesntlthis nature, the vari ouslburners greeeiveliuel from amanifold I 44 conne'ctd toxa v. source. or; iuel. supply. In this em- 14"Claims. (Cl. 158-130) 112 by agpipelfi to the manifold I4 and is/of'the constant burning type. 'An ignition pilot burner I1 is preferably included and is 'positioned'in lighting proximity to the main burner ID.

"The. main oven burner 10' is connected: to. the manifold M by a main fuel pipe I8 in which a :mainshut-ofiyalve' '20 and an electromagnetic safety shut-off 'means'22 are interposed as 'will be apparent hereinafter. The main shut-off valve 20 :may embody the usual thermostatic control devicewhic'h: isadjustablei in :common therewith "by: an operatingimeansin'the form of auknob 24" and 'beingresponsive to temperatures in the 'oven"where the burner-J0 is l'ocatedifAs .como bined shuteo'ff valves and thermostatic j devices are well known, further description is deemed unnecessary; it being understood'that the thermostatic device is capable" of controlling the flow of 'fuelin'thepipe 'l 8 independently. of the main shuti-oif 'valve' 20 "when the latter has once been opened. 'The fiow. of :fuel in the pipe 'latto'the mainburner I0 is" thus subject to the throttling action ofth'e" thermostatic device Where included.

"A pipe 25 which. is connected to.:the main shutpipe I8 to themain burner l0.

.Ihe, passage aliis'control-ledby a safetyiyalve r member 38 which is movable'into andoutvot-engagement with oneizside-ni': the partition-3 2 adjacentzthe' "inletstopening .28. The zval-ve' member wisibiasediby avcoil spring 40 intoengagement withiitsiseat on partition- 32. Ai closure disc "42 is: .:movable:- into engagement with the" opposite side of the partition 32 *and in 'suchposition serves to prevent 'flowof i'uel" through fthe vopening 34'; The closuredisci42-isslidab1y mounted on a reset stem M which:extends through the opening"3tinto'engagement with the valvelmember"381and serves to .move the latter against.,;the bias .orthe coil spring 40. .vThus -althoughnthe valvelmemberl38 islunseatediby such operation, the closure .disc is simultaneously .operated to prevent flow of fuel to the main burner Hi. Such interruption of fuel flow occurs during the resetting operation to be described hereinafter.

The side of the valve member 38 opposite to that engaged by the reset stem 44 is provided With a connecting stem 46 which carries at its opposite end an armature 48. The armature 48 is housed within a magnet housing 50 carried by the casing 26 and also enclosing a horseshoe magnet 52 having the usual winding 54 associated therewith. One end of the winding 54 is grounded on the magnet housing 50 and the opposite end is secured to a terminal connection 56 carried thereby.

The reset stem 44 projects through a closure cap 60 carried by the casing 26. A diaphragm element 62 extending across the inner face of the closure cap 60 and positioned between a pair of collars 58 on the reset stem 44 serves to seal against leakage from the chamber 30. A coil spring 64 extending between the closure disc 42 and the adjacent collar 58 serves to bias the closure disc 42 toward abutments 66 formed on the stem 44. A second coil spring 68 engages at one end with the closure cap 50 and at the opposite end with an abutment I carried on the terminal end of the reset stem 44. This spring 68 tends to bias the reset stem 44 outwardly of the casing 26 and is limited by engagement of the adjacent collar 58 with the closure cap 60.

The safety control means 22 also includes means to control the flow of fuel to an auxiliary pilot burner I2 and a thermocouple heating burner I4. The thermocouple heating burner I4 is connected by a fuel pipe I6 to the control body 26 while the auxiliary pilot burner I2 is connected by a branch pipe I1 from the pipe I6. The auxiliary pilot burner I2 is conveniently located at the rear of the top surface of the range and adjacent the control means 22 while the thermocouple heating burner "is located adjacent the main burner I0. Fuel from the main fuel chamber 30 is supplied to the pipe I6 by way of a passage communicating at one end with the chamber 30 and at the opposite end with a pilot valve chamber I8. The pilot valve chamber 18 is provided with a seat for a pilot valve member 80 in the form of a ball member biased toward the seat by a coil spring 82. When the pilot valve member 80 is disengaged from its seat fuel may flow from the passage 'I'5 to an outlet chamber 84 to which the pipe I6 is connected.

The pilot valve assembly is located in the body 26 laterally cf the safety valve member 38 and its associated parts, Thus, an operating stem 86 for the pilot valve member 80 extends therefrom through the outlet chamber 94 and issubstantially parallel with the reset stem 44. The stem 86 is reciprocable in a closure cap 88 provided with a sealing diaphragm 90 to prevent leakage of fuel at this point.

Resetting means for operating the reset stem 44 and moving the armature 48 into engagement with the magnet 52 and while simultaneously opening the safety valve member 38 takes the form of a lever device designated generally by the reference numeral 92. A lever 94 is p vot y mounted on a bracket 96 carried on a stationary portion of the range on which the apparatus is mounted. The lever 94 extends into engagement with the terminal ends of both the stems 44 and 86 and is adapted to be rotated on its pivot by a latching element 98 which is also pivotally mounted on the bracket 96 in common with the lever 94. The lever 94 and the latching element 98 are secured together by an elongated pin I00 which extends through both members and is provided with a pair of spaced cross-pins I02 one of which normally abuts the latching element 98 and the other of which is spaced from the lever 94. A coil spring I04 extends between the lever 84 and the cross-pin I02 which is spaced therefrom to provide a resilient connection of the lever 94 with the latching element 98. The arrangement is an override connection such that when the armature 48 is seated against the pole faces of the magnet 52, then any additional movement of the latching member 98 will be absorbed by compression of the coil spring I04 as the pin I00 moves relatively to the lever 94.

Movement of the latching element 98 on its pivotal mounting is effected by operating means responsive to rotation of the knob 24 of the main shut-off valve 20. To this end, a cam plate I06 is carried by the main shut-off valve and is rotatable jointly with the knob 24 thereof. The cam plate I06 is adapted during its rotation to engage an arm I08 secured to one end of a connecting rod I I 0 and to move the arm I08 through an arc of rotation. The connecting rod H0 is rotatably mounted in the bracket 96 at one end and in a support H2 at the opposite end which projects from the main shut-off valve 20. A torsion spring I I4 is mounted on the connecting rod H0 and has one end secured in the support H2 and its opposite end secured in the arm I 08 for the purpose of returning the connecting rod I I0 to its initial position ,as soon as the cam plate I06 has moved beyond the path of the arm I08. The arrangement is such that upon clockwise rotation of the knob 24 to open the main shut-off valve 20 and set the temperature at which the thermostatic control will operate, the cam plate I06 will also be moved in a clockwise direction and engage the arm I00 to rotate the connecting rod III) in a counterclockwise direction against the bias of the torsion spring I I4. After the arm I08 has been thus moved through an arc of rotation the cam plate I06 passes beyond the arm I 08 and frees it for return movement under bias of the torsion spring I I4,

The rotation of the connecting rod H0 is converted into a longitudinal movement for the purpose of operating the lever device 92 in the resetting operation of the safety control device 22. Such conversion of movement is effected by a nut II6 carried by the connecting rod H0 and supported by the bracket 96. The nut I I6 has a stud II8 mounted therein for reciprocable movement but being held against rotation therewith by a laterally'projecting arm I20 which engages with a slotted projection I22 carried by the bracket 96 for this purpose. The end face of the stud II8 operatively engages a lug I24 projecting from the'latching element 98 and by means of which the lever device 92 can be moved in a clockwise direction about its pivot on the bracket 96.

The latching element 98 is retained in a latched position by the provision of a thermal timing device comprising a pivoted bimetal element I26 which is biased to latching position by a coil spring I28. The coil spring I28 engages at one end with the control body 26 and at the opposite end with one leg of a bell-crank I upon the opposite leg of which the bimetal element I26 is secured at one end. The bimetal element I26 is torsozrrelease. thezlatching: element :98 wannabe-innreased.::;or'.;decreased: by? the provision :01 mu hdjustingzscrewid .32; canie'dmrna bracket: l 3 4:.on'the control :b.ody-:.2 Band-z engaging: the nlegctthezbellcrank. I30. "onltheisidei opposite that-engaged by thecoilspring I28.

When 1' the bimetal element 2 6 warps sum- .ciently and suddenly releases the latching element :98, "the .1 entire lever assembly 92 rotates counterclockwise :..about' its pivot :due chiefly :to the :bias oft-the :resetstem 'springx'BS acting on the::lever".94. Ordinarily, this rotation "would be in the; natureof .a. snap-action with the :pilot valve: stem '86 and. the reset stem 44 :moving: to the left as viewed in the drawing until: arrested bylthe. respective diaphragms: 90 .and 62 engaging their seats. .Suchcessation of the'snap=-acti'on wouldi'jar-or vibrate thesaiety v'alve body fli and tend 1301631158ImOVGmGHtTthBIBOf in the opposite direction vi due'to its own inertia. A' separation 'Oiithfi. armature :48 from the pole faces of the magnet 52 could therefore occur. This isobviously'tundesirable as the safetyvalve member 38" would tend to snap to closed position under biasof the coil:spring- 4Il.and shut off 'the flow of fuel? in. the main'iuel pipe I8 to the main burner. .I I]. Accordingly, this invention provides means for: slowing down' the counterclockwise movement of the sleverpdevice' 92 to prevent'the described undesirable closing of the safety valve 38 which might otherwise-occur.

:To this end, agearsector I36 is carried by the lever-94 on the side opposite the side engaged by the.:latching element :98. ..This gear sector -I'3'Ii me'shes'with' a pinion I38 forming part of a gear train of which a gear I40 and a second pinion I42 formtheother parts. "Rotata-ble'with the second pinion-I42is .abalance-Weight or fly-wheel 144 so. that'the entire assembly operation as will be apparent for retarding movement-ofthe lever device'92 upon return-movement of the latching element 98 andserves to prevent shock 'suiiicient' to cause separation of i the armature 38 from the pole faces of. the magnet 52.

The electromagnet comprising the winding "54 and-horseshoemagnet 52 is-adapted to beenergized by current generated from a thermocouple -I 46 which is connected by suitable leads to I the winding54 at the terminal connection -56. The thermocouple I46 is located so that the hot junc tion thereof will .be heated by a flame from the thermocouple heating burner ":14 which-receives aisupply ofrfuel from the pipe 'I-S 'as-previously described.

Axsystemcfiiash tubes .is provided "for: igniting the :various. .burners of the apparatus from the constant burning top pilot burner l 2 Accor-dingly; a: relativelyshort flash tube I48 isprovided between the constantuburning top ipilotburneri'l 2 andfthe auxiliary pilothurner 12, it being apparent that fuel. firomt'thebranch; pipe 1 L supplying the auxiliaryrpilot'burner I2 will enter the flash tube. I48 and heignitedjrom theconstant burningypilot, burner 'JIZ. :Theifiame so. created will be conducted-back through'theflashxtube I48 and will-ignite thefuelflowingiromthe auxiliary provided between. the auxiliary: :pilot. burner '12 and the thermocouple:heatinghurnerfl which -is remote therefrom. .IThis flash. tube EI5UCSEI'VBS tO cause ignition "of the thermocouple heating burner in a manner; similar to that described in connection withthefla'shtube .I'4B.

, .Thezheatof. theflamerfromthe thermocouple heating burner; won thethermocouple I 46 serves to. energizettheselectromagnetii2asumcientlyrrto 'holdflmm-annature fl in attractettpo'sition but the thermoeiectriecurrentzso generated .is incapable of'moving'zthe annature.'48:.to:this ;attracted:posi- .tion. .iHencepthexesettingmeanswhich have been describedmrerrelied:upon; for .this purpose.

In-the operation-oi'the:apparatus,:it:may be as sumed that the rpartszarexin thepo'sition shown in the:drawing;;namely; that thetresetting. deviceis in operationrandithat the thermocouple is still'being heated bythe thermocouple heating humerubut has znot-yetigenerated sufiicient current. tor-retain the larmatureitimagaxinst therpole faces of. 111118 magnet-50. .Thusgthezpartseare inwhat may be temnedifthexstarting position. In orderfi'i'zreach sucht positionzthe .dial 24 has been. rotated clockwise. to :effect operation zof 1the..arm 108 :in *a counterclockwise direction by theicaml plate I06. The.:consequentirrotation. .of th connecting "rod .I :Iu'shas caused: the: stud. I 'I 8' to-actuate the lever device 92::and' cause-movement of; the reset. stem 44-.iand zthe 'tpiiot halve irstemif86'i to. the: right. as viewed inzthe' -drawing. Such movement .of; the reset stemczflzcauses the :closure :'disc-" 42: to become-seated against theipartitionifl whereupon the stem- 445. moves'i'the' :.valve member "38 :away from fits seatxand the rarmature 48:.against the pole faces 0f the magnet .52. vlitlithe *samcrtime, the pilot'valvememberfafl."is;moved to an open position against" the bias :of: the: .COiISDliIlgLBI.

"The i clockwisetrotation. of the lever- Muduring thearesettingsoperatiom causes thesgearisectcr -I 38 to rotate: the r-gearing.. mechanism :descriheditota set-.qao'sition. .fFue'lzcan tnow fiowiromthemain shut=-off valve. '20 through :the :main'rfuelipipe' I 8 and passage I5iin'thecontrol body 26 to the r fuel pipe 16 which'ssuppliesthe.auxiliary pilot-burner I2 and the thermocouple :heatingburner I4. .Fuel

also flows through thepipe .2 5 to zthe'ignition pilot burner I1. Under. these conditions thefiame at the :constant hurning pilot :bumer I2. .zservesto ignite the auxiliary'spi lotfburner I2- and' the thermocouple heating. burner 14 through 'the flash 'tube' system previously. described. The. ignition set stem 58 being held inwardlyibyrthe.lever mem-.

hen-94.

-'-Asa-previously mentioned, the. clockwise'rotation of the cam plate i 06 eventually? causes it totmove past the arm I 08. during the :operation of. setting the di'al 24 at a desired .temperatu-remarking. 'As soon "as this occurs'the bias *of the .torsion spring II 4' causes the connecting rod H 0, and'1the tnut II fi a'nd' arm Iw-carried thereby, to rotate clockwise'tothe' initial position. The' stud I18 consequen'tly moves" longitudinally inthe nut I I6 to its retracted position butithe lever device 92 remains in'fiits actuated position-duetothe latching action of 'the bimetal element 126 now to ;beldescribed. l

"The rotation of "the leverxmem'ber 94in a clockwisedirection by operation of the "knob 2 4 causes the, latching lever 98 also to move in a clockwise direction away' from overlying relation with the bimetal "element f I 26. Due to the bias established by e 0011 Sp ing I28 on the bell-crank I.3Ii;1the bimetal arm I26 moves clockwise into;latchingpo- 'si tiom and maintains th'e'z'lever .memberxS 4.:in -its resetting position. Thus, during. the time-.zthat the thermocouple 1126 is becoming" heated :by :the

flame from the thermocouple heating burner I4, the bimetal element I26 is simultaneously bein heated by the flame from the auxiliary pilot burner I2. As the thermocouple I46 becomes heated it provides an electric potential which causes the magnet 52 to be energized for holding the armature 43 in attracted position and the valve member 38 in its open position.

When the bimetal element I26 becomes sufficiently heated it warps in a counterclockwise direction and releases the latching element 98. The entire lever assembly 92 then rotates in a counterclockwise direction about the pivot on the bracket 96 due chiefly to the bias of the reset stem spring 68 as previously described. Such return movement of the lever assembly 92 is retarded, however, by operation of the gear train I35, I38, I40 and I42 together with the inertia of the weight or fly-wheel I44 so that no shock sufficient to disengage the armature 48 and cause closing of the safety valve 38 can occur.

The pilot valve member 80 moves to closed position under bias of the coil spring 82 thus cutting off the supply of fuel to the auxiliary pilot burner I2 and the thermocouple heating burner I4. Simultaneously, the closure disc 42 moves to the left away from its seat on the partition 32 under bias of the coil spring 68. As the safety valve member 38 is now held in open position due to engagement of the armature 48 with the pole faces of the magnet 52, fuel is permitted to flow through the main fuel pipe I 8 from the main fuel chamber 30 to the main burner IO where it is ignited by the flame at the ignition pilot burner H which is now utilized for heating the thermocouple I46. It will be observed that the bimetal element I26 is permitted to 0001 during normal running conditions which should now ensue.

In the event that the flame at the pilot burner I1 is extinguished at the time that the bimetal element I26 releases the latching lever 98, then the armature 48 will not be held against the pole faces of the magnet 52 and the valve member 38 consequently closes under bias of the valve spring 40 to shut off the flow of fuel to the main burner IO. Also, during normal running operation any failure of a flame at the pilot burner I? will permit the thermocouple I46 to cool causing a similar release of the armature 48 from the magnet 52 and consequent shutting oiT of fuel supply to the main burner I0.

It will be apparent that an automatic means of resetting a thermomagnetic safety device has been provided and is operable by merely manipu lating the usual knob of a fuel cock from off to "on position or to a desired temperature setting where a combined thermostat and main shutoff valve 20 is provided. A positive rod connection operated by rotation of the knob 24 has been substituted herein for the less desirable pull-Wire operated by rotary motion as in the copending application. Moreover, the preservation of the life of the bimetal element I26 due to the limited heating time thereof remains a feature.

It will be apparent that many changes may be made in the details of construction and arrangement of parts without departing from the scope of the invention so that this description and accompanying drawing are intended by way of illustration only and are not to be construed in a limiting sense.

We claim:

1. A control apparatus for fuel burners having main and pilot burners, a main shut-off valve rotatable between positions for controlling the 8 fuel supply to the burners, valve means for controlling the fuel supply to the burners and being located remote from said main valve, operating means for rotating said main valve, a lever device movable into operative engagement with said valve means for conditioning the same to supply fuel to the pilot burner, connecting means for moving said lever device upon operation of said operating means, and a thermal timer biased into latching engagement with said lever device for holding the same in said operative engagement, said timer being responsive to a flame at the pilot burner for terminating said latching engagement after a predetermined period following operation of said operating means.

2. A control apparatus for fuel burners having main and pilot burners, a main shut-off valve rotatable between positions for controlling the fuel supply to the burners, valve means for controlling the fuel supply to the burners and being located remote from said main valve, operating means for rotating said main valve, a lever device movable into operative engagement with said valve means for conditioning the same to supply fuel to the pilot burner, a latching element carried by said lever device, connecting means engageable with said latching element for moving said lever device into said operative engagement upon rotation of said operating means, and a thermal timer biased into latching engagement with said latching element for holding said lever device in said operative engagement, said timer being responsive to a flame at the pilot burner for terminating said latching engagement after a predetermined period following operation of said operating means.

3. A control apparatus for fuel burners having a main and a pair of pilot burners, a main shutoif valve rotatable between positions for controlling the fuel supply to the burners, operating means for rotating said main valve, safety valve means movable between open and closed positions for controlling the supply of fuel to the main burner and being biased to said closed position, electromagnetic means operatively associated with said safety valve means for holding the same in open position when said electromagnetic means is energized, thermoelectric means responsive to the heat of a flame at one of said pilot burners for energizing said electromagnetic means, and resetting means operative for positioning said safety valve means in said open position, said resetting means including a lever device movable to a resetting position in operative engagement with said safety valve means, a latching element carried by said lever device, connecting means engageable with said latching element for moving said lever device to said resetting position upon rotation of said operating means, and a thermal timer biased into latching engagement with said latching element for holding said lever device in resetting position, said timer being responsive to the heat of a flame at the other said pilot burner for terminating said latching engagement after a predetermined period following operation of said operating means.

4. A control apparatus for fuel burners having a main and a pair of pilot burners, a main shut-off valve rotatable between positions for controlling the fuel supply to the burners, operating means for rotating said main valve, safety valve means movable between open and closed positions for controlling the supply of fuel to the main burner and being biased to said closed position, electromagnetic means operatively associated with said safety valve means for holdingzthesame inxopen position when," said; electromagnetic: means? is energized, thermoelectric. means responsive to the heat .of a llama at .onerof said pilot burners for energizing said electromagnetic means, and resetting means operative for positioning said safety valve means in said open position; saidresetting means including a lever device;movable; to ;a re,- setting position in operative enga ement with said safety valve means, a-la'tchingelement carried by said lever device, connecting means engageable with said latching elementifor moving said lever/device to said resetting aposition uponrotation of saidoperatingmeanssaind a pivotcdnbimetal element biased intoilatching engagement with said latching element and operative for maintaining said lever device in said resetting position, said bimetal element being responsive to the heat of a flame at the other said pilot burner for releasing said latching element for movement out of resetting position while said electromagnetic means holds said safety valve means in open position.

5. A control apparatus for fuel burners having main and pilot burners, electromagnetic safety valve means operable between open and closed positions for controlling the flow of fuel to the main burner and being biased to closed position, a lever device movable into operative engagement with said safety means for overcoming said bias, a

thermal timer biased into latching engagement with said lever device for holding the same in said operative engagement, said timer being responsive to a flame at the pilot burner for terminating said latching engagement after a predetermined period after initial movement thereof, and means operatively associated with said lever device for retarding the rate of return movement of said lever device when said operative engagement is terminated.

6. A control apparatus for fuel burners having main and pilot burners, electromagnetic valve means operable between open and closed positions for controlling the flow of fuel to the main burner and being biased to closed position, a lever device movable into operative engagement with said electromagnetic valve means for overcoming said bias, a thermal timer biased toward latching engagement with said lever device and being responsive to the heat of a flame at the pilot burner for terminating said latching engagement, means for moving said lever device and establishing said latching engagement, and means operatively associated with said lever device for retarding return movement of said lever device when said latching engagement is terminated.

7. A control apparatus for fuel burners having main and pilot burners, safety valve means movable between open and closed positions for controlling the supply of fuel to the main burner and being biased to closed position, electromagnetic means including a movable armature connected to said valve means for holding the same in open position when said electromagnetic means is energized, a lever device movable into operative engagement with said safety valve means for overcoming said bias, a thermal timer biased toward latching engagement with said lever device and being responsive to the heat of a flame at the pilot burner for terminating said latching engagement while said armature holds said safety valve means in said open position, means for moving said lever device and establishing said latching engagement, and gearing mechanism rotatable upon movement of said lever device for rehen: Sa d-l ch n nga ement is. rmina ed nd. P v t n -s d mei i' r-pau a aon o e m rsi nei e r ie e i means"- i .nectedto-said safetyzvalvezmeansvfonholdingLthe same in open position when said electromagnetic means is energized, thermoelectric means responsive to the heat of a flame at one of said pilot burners for energizing said electromagnetic means, resetting means operative for positioning said safety valve means in said open position, said resetting means including a lever device movable to a resetting position in operative engagement with said safety valve means, a latching element carried by said lever device, connecting means engageable with said latching element for moving said lever device to said resetting position upon rotation of said operating means, a pivoted bimetal element biased into latching en gagement with said latching element and operative for maintaining said lever device in said resetting position, said bimetal element being responsive to the heat of a flame at the other said pilot burner for releasing said latching element for return movement out of resetting position while said electromagnetic means holds said safety valve means in open position, and weighted gearing mechanism rotatable upon movement of said lever device for retarding movement of said lever device upon return movement of said latching element and preventing shock suificient to cause separation of said armature from said electromagnetic means.

9. A control apparatus asclaimed in claim 3 wherein pilot valve means are provided for controlling the supply of fuel to at least one of said pilot burners, said pilot valve means being movable between open and closed positions and cooperable with said lever device to be moved to said open position when said lever device is moved to said resetting position.

10. A control apparatus as claimed in claim 4 wherein pilot valve means are provided for controlling the supply of fuel to at least one of said pilot burners, said pilot valve means being movable between open and closed positions and cooperable with said lever device to be moved to said open position when said lever device is moved to said resetting position.

11. A control apparatus as claimed in claim 5 wherein pilot valve means are provided for con trolling the supply of fuel to said pilot burner, said pilot valve means being movable between open and closed positions and cooperable with said lever device to be moved to said open position when said lever device is moved into said operative engagement.

12. A control apparatus as claimed in claim 6 wherein pilot valve means are provided for controlling the supply of fuel to said pilot burner, said pilot valve means being movable between open and closed positions and cooperable with said lever device to be moved to said open position when said lever device is moved into said operative engagement.

11 13. A control apparatus as claimed in claim '7 wherein pilot valve means are provided for controlling the supply of fuel to said pilot burner, said pilot valve means being movable between open and closed positions and cooperable with 5 with said lever device when said lever device is 15 2,311,127

12 moved to said resetting position to be moved against its bias to an open position. VICTOR WEBER. WILLIAM J. RUSSELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,049,958 Jones, et a1. Aug; 4, 1936 2,049,960 Jones, et al Aug. 4, 1936 2,236,673 Cole Apr. 1, 1941 Robinowicz Feb. 16, 1943