US2455521A - Safety control for gaseous fuel burners - Google Patents

Description

Dec. 7, 1948. w IETAL 2,455,521

SAFETY CONTROL FOR GASEOUS FUEL BURNERS Filed April 26, 1945 2 Sheets-Sheet l I a A n 650m: B. SOLOVIEFF, and Hana/.0 W- RICE.

" a 1- T'ORNIifY.

5 m a I I INVENTO RS.

Dec. 7, 1948. H. w. RICE ETAL 2,455,521

SAFETY CONTROL FOR GASEQUS FUEL BURNERS Filed Apfil 26, 1945 2 Sheets-Sheet 2 INVENTORS. Gaoeas 5.6azavzzFF, a Hana .0 W. Rzce.

BY W/T/QM n-rromver.

Patented Dec. 7, 1948 SAFETY CONTROL FOR GASEOUS FUEL BURNERS Harold W. Rice, Los Angeles, and George B. Soloviefl, South Gate, CaliL, assignors to Robertshaw-Fulton Controls Company, a corporation of Delaware Application April 26, 1945, Serial No. 590,470

16 Claims.

This invention relates to safety control apparatus for fuel burners and, more particularly, to combined resetting and indicating devices for thermomagnctic safety controls.

One object of the invention is to reset the thermomaghetic safety device and indicate the control position by a common operation.

Another object of the invention is to facilitate the resetting operation by utilizing the simple rotation of a dial for this purpose.

Another object of the invention is to indicate clearly the operationalsequence for resetting the control.

Another object of the invention is to automatically retain the setting dial in an operated position if the control is properly set in operation.

Another object of the invention is to automaticall return the setting dial to unoperated position if the control is not functioning.

Another object of the invention is to prevent flow of fuel to the main burner during the resetting operation while permitting such flow to a pilot burner.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings,

wherein Fig. 1 is a cross section to a thermomagnetic safety control embodying the invention;

Fig. 2 is a partial cross section of the control shown in Fig. 1 but showing the operating parts in another position;

Fig. 3 is a View similar to Fig. 2 but showing the parts in still another operating position;

Figs. 4, 5 and 6 are plan views showing the indicating device in various positions;

Fig. 7 is a plan view of a detail;

Fig. 8 is a side elevation of the detail shown in Fig. 7; and

Fig. 9 is a perspective view of the detail shown in Figs. '7 and 8.

Referring more particularly to the drawings, the safety control comprises a casing in provided with an inlet I2 and an outlet l4 suitably threaded for connection to a gaseous fuel supply pipe l5 which supplies fuel to a main burner (not shown). The casing I0 is provided with an interior partition l6 between the inlet l2 and outlet l4 having an annular valve seat l8. For a purpose which will be apparent hereinafter, the interior wall of the annular valve seat member I8 is provided with a circumferential recess positioned intermediate the ends of the member and defining the margin of a conical opening 22 which extends from one end of the valve seat member I8. I

The opposite end of the valve seat member I8 is adapted to be engaged by a disc valve member 24 which is biased to its seat by a coil spring 26. A closure plate 28 surmounts the end of the casing I0 beyond the valve member 24 and provides an abutment for the opposite end of the spring 26. A valve stem 30 projects from the valve member 24 through the closure plate 28 and suitable packing 32 may be provided to seal the closure plate against leakage past the valve stem 30.

The projecting end of the valve stem 30 carries an armature 34 cooperable with the pole faces of ahorseshoe magnet 36 and being spaced therefrom when the valve member 24 is engaged with the valve seat IS. The magnet 36 is secured to a hood 38 which is carried by the closure plate 28 and suitably insulated therefrom. The usual coil or winding 40 is provided for the magnet 36 and has one end grounded on the hood 3B and the opposite end connected to a terminal conductor 42 suitably insulated from the hood 3B and projecting to the exterior thereof.

Abutting against the underside of the valve member 24 is a spring plate 44 in the form of a narrow strip of yieldable material having a plurality of depending fingers 46 engageable with the conical opening 22 in the valve seat member l8. The spring plate 44 is engaged on the underside by one end 48 of a connecting stem 50. While the valve member 24 is not secured to the connecting stem 50 in order to permit floating movement relative to the valve seat member l8, it is apparent that a threaded or other connection could be provided at this point. The opposite end of the connecting stem 50 threadedly engages with a reset stem 52 which extends through a housing 54 carried in the bottom of the casing Ill. The reset stem 52 is provided with a head 56 which may conveniently be' formed by undercutting a recess 55 in the adjacent end of the stem 52 but which could be equally well formed by making the head 56 of larger diameter than the stem 52 as will be apparent. In addition, the reset stem 52 is provided with a collar 58 intermediate the ends thereof and adapted to be engaged by a slidable element in the form of a thimble 60 mounted in the housing 54.

The thimble 60 is retained in the housing 54 by the provision of an annular flange 62thereon which engages with the wall of a recess 64 formed in the housing 54 for this purpose. As previously indicated, the thimble 60 is adapted for slidable movement in the housing 54 and willinltially move relative to the reset stem 52 which extends therethrough. However, subsequently to this initial movement of the thimble 68, the upper face thereof engages with the collar 58 on the reset stem 52. Upon further slidable movement of the thimble 68 relative to thehousing 54 a joint movement of the thimble .68 and thereset stem 2'-wi1 l occur relative to the housing 54.

As such movement of the reset stem 52 will cause corresponding movement of the connecting stem 58 and the valve member 24, it will be apparent that fuel will flow from the inlet I8 past,

the valve seat member I8 andbetween the fingers 46 to the outlet I4. It ls assumed that the control device will be provided with a pilot burner, as indicated at 66, and means are provided for supplying such burner with fuel when the valve member 24 is off its seat while at the same time preventing flow of fuel from the outlet I4. Thus, as will now be explained, during the operation of resetting the armature 84 against the pole faces of the magnet 38 only the pilot burner 88 is supplied with fuel.

To this end, a duct 68 is provided in the valve seat member I8,.preferably between the recess 28 therein and the seat for the valve member 24, and this duct 68 communicates with a passage I8 extending through the casing I8 into communication with the pilot burner 66 which is supported thereby. The flow of fuel to the outlet I4 is prevented by a flow interrupting device comprising a closure disc I2 slidably mounted on the reset stem 52 beyond the collar 58. The disc 12 is of sufllcient area to extend beyond the periphery of The closure disc 12 has a yieldable diaphragm I6 secured at its peripheral edge thereto and clamped between the connecting stem 58 and the reset stem 52 at its inner portion. A pair of sealing rings 18 and 88 are secured respectively to the peripheral portions of the diaphragm I6 and the closure disc 12 for alternative engagement with the valve seat member I8 and the housing 54, respectively. A coil spring 82 extends between the underside of the closure disc I2 and the upper side of the flange 62 formed on the thimble 68 and serves to bias these elements apart.

The pilot burner 66 is located in proximity to a thermocouple 84 having one lead 86 electrically connected to the terminal conductor 42 and the other lead 88 grounded on the hood 38. The thermocouple 84 is thus adapted to be heated by a flame from the pilot burner 66 but is incapable of generating sufilcient current to attract the armature 34. However, the thermocouple 84 will generate sufficient current to retain the armature 34 against the pole faces of the magnet 86 after the armature has been moved into engagement with the pole faces by operation of the reciprocable means including the thimble 68 and reset stem 52 as will now be described.

Secured to the housing 54 is a support plate 88 which may be circular and have its axis offsetfrom the axis of the housing 54. A dial plate 82 is carried by the support plate 88 in axial alignment therewith but longitudinally spaced therefrom. The dial plate 82 is perforated to permit the head 56 of the reset stem 52 to extend therethrough in different longitudinal positions depending upon the position of the reset stem 52. Rotatable means in the form of a handle 84 and tened to underside. otthh qg 84 adjacent menial plate 82""across'wliich it is movable by rotation of the handle 84. -The pointer I82 is 'thus adapted to register with indicia. I84 on the "outer'snrface of the dial plate 82 comprising the words fOil," Qn and Light pilot" arranged in "spaced sedueneasshown in Fig. 4. A torsion "spr ng I86 is 'niounted between the handle 84 and the dialplate S'Zlfa'nd serves to bias the handle 84 in a counter-clockwise direction.

A'cam discf-shewci in detail in Figs. '7, 8 and 9 and designated generally by the reference numeral I88, is fastened to the stem 86 between the collar I88 and the inner face of the dial plate 92 for rotation' relfative'tothe latter: when the handle 94- is rotated. mee nr plate I88 may be formed irem asih gle'sheet-"er material and has en-easetjseg'nentpdaiea 'I I8 thereon from the plane of 'thelplatejPreferably. the offset portion Il8ha's esiepmg raeejiz. a level face m fo'rmin'gthe higl'i'pdint ofithefcarii and an end face 'II 8 extendingsubs tanti allynormal to the plane of thepamfli'sc lflflfi'he' oflse't portion H8 may conveniently? be formdfby slitting the cam-disc I 8 8 qn theareiiate inner peripher H8 of the segme t ge -magma formed. It will be apparent hewever liat 'th'eoiliset portion I' I8 could 'be'formed' 'froirifaseparate piece of material welded "orotherwi sjefsecured to the walls of 'a segmental openingif ormd infthe cam disc I88.

An arcuate sl9tl28 formed in the cam disc "*8 adieee it' s e ehe' -a 'exte d s through substantially I88 'fdegijees o jf'fthe circumference thereof; 'The arcuat slot' I2 '8is' located partly in the'slpping facedlzf'andin'jthe level face 4 ofthe offset p6rtion I'I'8 where it takes the form of an enlargement 122 ternnnatingadjacent the face: H6; Atthe oppbsiteend of the enlargement I 2-: wmenfis iieyqriaftire foff'set portion I I8 is a' shoulder 'l2 '4'fforrhed at'the junction of the enlargement 1Z21Wlthi thefnarzg wer part of'slot I28. The enlargement 'l 22 tlius -terminates sub- 'stantiallymidway of the ends'ofthe'fslot I28 and 'belyondfth'e 881130611 8 eird'of t h e'ofl'sfet' portion H8.

The enlargement" I22 isjadapted to receive the head 55 b'f'there'set 52 but th head is unable to enter the narrower'portiqn of the slot I28 beyond the shoulder"I 24. The reduced portion 55 of'the' reset'steni 52 however; capable of entering the"na1frower pbrtiop"o i';' tl 1e slot I28 beyond the-shoulder I24 lfora purposewhich will be hereinafterfapparent? n Th" ;cani disc I 88 is mounted on the tem at infsumposinon relative to the dial plate 92 thatfwhenthe'operating parts of h n ra ar int1ij 9 iin awii 1 then the reset stei n szis located at the end of the narrow pdrtion'of 'slo I 28 remote from shoulder I24 "wh'icl i"i' s f'Lijght'piidtj position as shown in mg; 4; 1 The p6f1nteif, I82: w en 1 indicates the "on" position,b'elnglocatedjopposite the end of the erflargeinent I22 remote from the shoulder l2- I m'the o erationf ciprocal means includingthe reset stem 52 and 1. The pointer I02 is then in the position shown in Fig. 4 indicating that the fuel flow is turned "Off." Rotation of the handle 94 in a clockwise direction will engage the sloping face II2 of the cam disc I08 with the projecting end of the thimble 60. Further movement in this direction will cause the thimble 60 to ride up the sloping face H2 and engage the level face H4 of the cam disc with consequent slidable movement of the thimble 60 relative to the housing 54 and the reset stem 52. During this rotation of the cam disc H08, the slot I therein hasmoved relatively to the reset stem 52 so that the stem is now within the enlargement I22.

As soon as the thimble 6015 moved by the cam disc I88 inwardly of the housing 54 the force applied by the spring 82 is transmitted to the closure plate 12 against the bias of the spring I4. As the spring 82 is stronger than the spring I4, the closure disc 12 is moved toward the valve seat member I8 causing the sealing ring 18 to be moved into sealing engagement therewith. The thimble 60 now engages with the shoulder 58 on the reset stem 52 causing a joint movement of the thimble and reset stem inwardly of the housing 54. The inward movement of the reset stem 52 is communicated by the connecting stem 50 and the spring plate 44 to the valve member 24 which is lifted off its seat against the bias of the spring 26 and the armature 34 is placed in engagement with the pole faces of the magnet 36. The depending fingers 46 of the spring plate 44 ride up the conical inner surface wall of the opening 22 of the valve seat member I8 and snap into the recess 20 formed therein. Thus, the connecting stem 50 is retained in the raised position with the valve member 24 open and the armature 34 in engaged position. The reset stem 52 is now located with respect to the cam disc I08 at the end of the enlargement I22 remote from the shoulder I24 and the head 56 is in the plane of the cam disc I08 received within the enlargement I22. The pointer I02 is indicating the Light pilot position as shown in Fig. 5 and the operating parts are in the positions shown in Fig. 2.

The valve member 24 being now disengaged from the valve seat I8, fuel is permitted to flow from the inlet I2 through the duct 68 and passage 10 to the pilot burner 66 where it can be ignited. It will be apparent that as the flow interrupting device is operative with the sealing ring I8 engaged with the valve seat mem ber I8 no fuel can flow from the outlet I4 to the main burner. The flame from the pilot burner 66 heats the thermocouple 84 and generates sufilcient current for the coil to energize the magnet 36 and retain the armature 34 in engagement with the pole faces thereof.

This resetting operation occupies but a few seconds and then the handle 34 can be released. The torsion spring I06 will return the handle and pointer I02 in a counter-clockwise direction causing a corresponding movement of the cam disc I08. However, as the head 56 of the reset stem 52 is now held in the plane of the slot I20 by the position of the reset stem 52, the cam disc I08 can rotate only until the shoulder I24 engages the head 56. When such engagement occurs the pointer I02 is indicating the On position which is intermediate the OE and Light pilot positions on the dial plate 92 as shown in Fig. 6.

It is apparent, therefore, that while the rotatable means of this device comprising the handle 84 and cam disc I08 can move in a forward direction throughout 180 degrees of movement, the rotation of the rotatable means in a reverse direction is substantially one-half the rotation in forward direction provided that the armature is reset. Should the armature 34 for some reason fail to be retained in engagement with the pole faces of the magnet 36 then the reduced portion of the reset stem 52 would be in the plane of the arcuate slot I20 and the shoulder I24 would be ineffective to limit the rotation of the cam disc I08 in reversedirection.

As during the reverse rotation of the cam disc I08 the level face H4 is moved away from the thimble 60 and the sloping face H2 is also subsequently moved away, the thimble 60 is moved by the spring 82 to its initial position as shown in Fig. 3. The release of the pressure of the spring 82 on the closure plate I2 will permit the spring 74 to bias the closure plate "I2 to disengage the sealing ring I8 from the valve seat member I8. The other sealing ring 80 is now moved into engagement with the housing 54 serving to prevent leakage of fuel past the thimble 60 or the reset stem 52 as might occur now that the valve 24 is off its seat. Thus, fuel from the inlet I2 to both the pilot burner 66 and the outlet I4 to the main burner now occurs as long as the current generated by the thermocouple 84 continues.

In the event that'the flame from the pilot burner 56 is extinguished and the thermocouple 84 ceases to generate sufficient current to retain the armature 34 in engagement with the pole faces of the magnet 36, then the flow of fuel to the main burner through the outlet I4 and to the pilot burner 66 is automatically shut off. In this operation, the valve member 24 is moved into engagement with the valve seat member I8 by the bias of the spring 26 causing disengagement of the depending fingers 46 of the spring plate 44 from the recess 20. The connecting stem and reset stem 52 are thus moved to initial position with the head 56 beyond the plane of the cam disc I08. 2 The arcuate slot I20 in the cam disc I08 now moves relative to the reset stem 52 due to the reduced portion thereon being in the plane of the cam disc I08. The torsion spring I06 which serves to rotate the rotatable means including handle 94 in a counter-clockwise direction will cause the pointer I02 carried thereby to register-with the Off" position on the dial plate '92 giving visual warning to the operator that the device is inoperative.

The safety control of this invention eliminates confusion and danger in igniting the pilot of an appliance with which the control is used. A single dial is used for resetting and indicating purposes. The operator is protected from the flow of fuel to the main burner during the operation of lighting the pilot burner. Moreover, visual indication is afforded of the position of the valve member in the Off and On positions thereof. In addition, visual indication is afforded of the precise position in which the handle should be placed while the pilot burner is being lighted.

It will be apparent that many changes can be made in the arrangement and combination of parts and in the details of construction herein disclosed within the scope of the appended claims without departing from the spirit of the invention.

We claim:

1. In a control device, the combination of controlling means movable between fiow permitting and preventing positions, an electromagnetic device having an armature operative for retaining said controlling means in" said flow permitting position, means fol-resetting said armature moperative position relative to said electromagnetic device including reciprocable meansoperatively associated wtih said armature and controlling means, rotatable means movable to an operative position for operating saidreciprocabie means, means for biasing said rotatable means to .an inoperative positiominterengaging means on said reciprocable means and said rotatable means effeotive in said operative position for preventing return movement of said rotatablemeans under said bias to said inoperative. position when said armature is reset, and indicating means cooperable with said interengaging means for defining positions of said controlling means corresponding to the operative or inoperative position ofsaid rotatable means.

2. A control device comprising a casing having inlet and outlet passages and a valve seat, valve means cooperable with said seat for controlling the flow between said passages, said valve means having a plurality of operative positions relative to said seat including full and minimum flow positions, an electromagnetic device having an biased to one position and being movable therefrom to cause said valve means to assume said minimum flow position, and means carried by said casing and engageable with said reciprocable means for limiting return movement thereof under said bias when said armature isreset and causing said valve means to assume said full flow position.

3. A control device comprising a casing having inlet and outlet passages and a valve seat, valve means cooperable with said seat for controlling the flow between said passages, said valve means having a plurality of operative positions including full and minimum flow positions, an electromagnetic device having an armature operative for retaining said valve means in said full flow position, means for resetting said armaturein operative position relative to said electromagnetic device including reciprocable means operatively associated with said armature and said valve means, rotatable means biased to one position and being movable against said bias to another position for operating said reciprocable means to cause said valve means to assume said minimum flow position, interengaging means on said reciprocable means and said rotatable means efiective in said other position for preventing return movement of said rotatable means under said bias to said one position when said armature is reset and limiting said return movement to an intermediate position to cause said valve means to assume means movable between positions for controlling the flow of fuel, an electromagnetic device having an armature operable for retentively positioning said controlling means when said device is energized, means for resetting said armature relative to said electromagnetic device incl'u'ding a'reciprocable stem for operating-said armature and controlling means,'means carried by said stem for limited slidable 'move'mentthere on, rotatable means 'oii'set from-said 's'temw'alv cam element carried by said rotatable means tor movementinto and out of engagement with said slid able 5 means for efl'ecting' said limited reliable movement followed by operation. of said= stem, and means operable bysaid slidablemeans dur ing said limited slidable movement therflol for interrupting the flow of fuel :to. the burner duriing the resetting operatiom; -5. 'A-- safety control for fuel burners comprising means movable between positions \for, controlling the flow of fuel, anelectromallfletic-device having-an. armature operable fox-.retentively PO31:- tioning said controlling means when said device is energized, -means for resetting. said armature relative to said electromagnetic device including reciprocable means operatlvely associated said armature and controllingi neans, rqtgtable means ofiset from said reciprocable me ans,.,an element carried ,bysaid rotatabl means 19F movement into and out of enga ement. with said reciprocable means for. operatinglthe same, means carried, by said reciprocable means for. interruptinsithe flow of fuel' during the reset goperaltion, and means operatively associatedwitl said flow interrupting means for, preventiiigflieelkage of fuel past said reciprocable' means upon com1- 'pletion of the resetting operation." I f 6.'1A safety control for fuel burners'con il-sing a casing having a valve'se'at therein, a aw ingber engageable with one side of said'valve sea t, an electromagnetic device having ani 'a'rmature spaced from "saidvalve member and movable'bejtween attracted and released positions, a stem for operating said'armature and valve ,member and projecting beyond saidcasing, means'car} ried by the projecting end of jsaidstein for limited slidable movement thereon in a first directioirtdjward said :valve" seat, said slidable means 'folniling a closure for said casing and beingengageable therewith for limiting said 'slidableh 'ovement in a second direction away nemsaid valve seat, means carried by said 'casingj'and" operable for moving'saidslidable' meansin said first direction," means responsive to the'last said movement of th'e slidable means for engaging in flowlintjerrupting relation'with the opposite side 'of"s'ai'd valve seat fromsaidvalve membenjsaid'stembe ing thereafter moved by further operatibn'of said movi'n'g means to un'seat'said valve ineinbr aii'd reset-said armature in attracted positionfnieans carried by said stem and engageabie'with said valve seat for retainingfsaid stem in 'saidl'no'ved position, yieldable means operable between said slidable means and'said nqwinterruptingmeans for returning said 'slidable-mean's in said-second direction upon cessation of-operation'oi said my: me means, and" means associated with said new interruptin means and engageable withsaid casing upon said return movem nt o'f'said su able means for sealing 's'aid casin s '7. A safety control for fuel burners comprising a 'casinghaving a valve seatthereim a'valve meni- -be'r engageable with one'side ofls'aid 'valve s'eat, an electromagnetic dev'icehaving an armature spaced fro'msaid valvei nember 'andmovable between attracted and released p ositi dns,"a' stem for o e ti a rma u i s va v mb a pro e i e's o d said va v ,ma he Z itteriorly of said casing.'a tlii mble slidably mounted on the projecting end 'of' said an' d a closure for said casing, said stem having a shoulder thereon engageable by said thimble for limiting slidable movement thereof in a first direction toward said valve seat, said thimble having a shoulder thereon engageable with said casing for limiting slidable movement of said thimble in a second direction away from said valve seat, manually operable means carried by'said casing for moving said thimble in said first direction, meansresponsive to the last said movement of the thimble for engaging in flow interrupting relation with the opposite side of said valve seat from said valve member. said stem shoulder being thereafter engageable by said thimble for moving said stem to unseat said valve member and reset said armature in attracted position, means carried by said stem and engageable with said valve seat for retaining said stem in said moved position, and yieldable means operable between said thimble and said flow interrupting means for returning said thimble in said second direction upon cessation of operation of said manually operable means.

8. A safety control for fuel burners comprising a casing having a valve seat therein, a valve member engageable with one side of said valve seat and biased to closed position, an electromagnetic device having an armature spaced from said valve member and biased to a released position, a stem associated with said armature and valve member and operable for moving said valve member to open position and said armature to attracted position, a thimble carried by said stem and projecting beyond said casing, said stem having a shoulder thereon engageable by said thimble for limiting slidable movement thereof toward said valve seat, flow interrupting means carried by said stem and engageable with the opposite side of said valve seat from said valve member, means for biasing said flow interrupting means away from said valve seat, manually operable means carried by said casing for moving said thimble toward said valve seat, and yieldable means between said thimble and said flow interrupting means for transmitting movement of one to the other, said biasing means being overcome by said thimble movement for engaging said flow interrupting means with said valve seat, said stem shoulder being thereafter engageable by said thimble for moving said stem to open said valve while said flow interrupting means remains engaged with said valve seat.

9. In a control apparatus, control means reciprocal between positions of operation, means for biasing said control means to one of said positions, means for actuating said control means against its bias to another said position including a control member offset from said control means and adapted for manual rotation in a forward direction, spring means for returning said member in a reverse direction when manual operation is terminated, means carried by said control member and having an arcuate slot therein, and a stem projecting from said control means into said slot for limiting the rotation of said control member in both said directions.

10. In a control apparatus, control means reciprocable between positions of operation, means for biasing said control means to one of said positions, means for retaining said control means in another said position but being incapable of actuating it to said other position, means for actuating said control means against its bias to said other position including a control member offset from said control means and adapted for manual rotation in a forward direction, spring means for returning said member in a reverse direction when manual operation is terminated, means carried by said control member and hav-- ing an arcuate slot therein defining three control positions one of which is intermediate the. other two control positions, and a stem projecting from said control means into said slot for limiting the rotation of said control member in said forward direction to establish one of said control positions and in said reverse direction to establish the other two control positions, said intermediate position being established only if said control means is retained.

11. The combination with a controlling means movable between positions and biased to one of said positions, means for retaining said controlling means in another position against its bias but incapable of actuating it from said one position, of means for actuating said controlling means including reciprocable means associated with said controlling means, rotatable means offset from said reciprocable means, a cam disc movable by said rotatable means into operative engagement with said reciprocable means for actuating said reciprocable means, said disc having an arcuate slot therein into which said reciproca ble means is adapted to project, and means operatively associated with said disc and rotatable means for defining control positions for the latter corresponding to the positions of said contrlling means, said reciprocable means and slot cooperating to retain said rotatable means in one control position when said controlling means is retained in said other position thereof.

12. The combination with a controlling means movable between positions and biased to one of said positions, means for retaining said controlling means in another position against its bias but incapable of actuating it from said one position, of means for actuating said controlling means including reciprocable means associated with said controlling means, rotatable means ofiset from said reciprocaible means, a cam disc movable by said rotatable means into operative engagement with said reciprocable means for actuating said reciprocable means, said disc having an arcuate slot therein provided with an enlargement at one end terminating at the median portion thereof, said reciprocable means being adapted to project within said slot and having a head engageable with said enlargement but incapable of entering beyond said median portion, a dial plate through which said reciprocable means and rotatable means are adapted to project and having indicia defining control positions for the latter corresponding to the positions of said controlling means, and a pointer carried by said rotatable means and movable relative to said indicia, said reciprocaible means and slot cooperating to limit the rotation of said rotatable means in both directions and said enlargement and head cooperating to retain said rotatable means in one control position when said controlling means is retained in said other position thereof.

13. A safety control for fuel burners comprising means movable between positions for controlling the flow of fuel, an electromagnetic device having an armature operable for retentively positioning said controlling means when said device is energized, means for resetting said armature in engagement with said electromagnetic device including a reciprocable stem for operating said armature and controlling means, means carried by said stein for limited slidable movement thereon, rotatable means offset from said stem and adapted for forward and reverse rotation, an element carried by said rotatable means for movement into and out of engagement with said slidable means for eflecting said slidable movement followed by operation of said stem during said forward rotation, and means operatively associated with said element and stem for limiting the rotation of said rotatable means in one direction to less than the rotation in the other direction when said armature is reset.

14. A safety control for fuel burners comprising means movable between positions for controlling the flow of fuel, an electromagnetic device having an armature operable for retentively positioning said controlling means when said device is energized, means for resetting said armature in engagement with said electromagnet device including a reciprocable stem for operating said armature and controlling means, means carried by said stem for limited slidable movement thereon, rotatable means offset from said stem and adapted for forward and reverse rotation, an element carried by said rotatable means for movement into and out of engagement with said slidable means for effecting said limited slidable movement followed by operation of said stem during said forward rotation, an arcuate slotted portion on said element hav an enlargement terminating intermediatethe ends thereof, and a head on said stem movable into operative engagement with said enlargement by said stem operation for limiting the rotation of said rotatable means in reverse direction to substantially one-half the rotation in forward direction when said armature is reset.

15. A safety control for fuel burners having main and pilot burners comprising means movable between positions for controlling the flow of fuel to the burners and being biased to one of said positions, an electromagnetic device having an armature operable for retentively positioning said controlling means when said device is energized, thermoelectric means exposed to a flame from the pilot burner for energizing said electromagnetic device, means for resetting said armature in engagement with said electromagnetic device and actuating said controlling means against its bias to another position including a reciprocable stem for operating said armature and controlling means, means carried by said stem for limited slidable movement thereon, means responsive to said limited slidable movement for interrupting the flow of fuel to the main burner during the resetting operation, rotatable means offset from said stem and adapted for rotation in forward and reverse direction, a cam disc carried by said rotatable means and movable into engagement with said slidable means for effecting said limited slidable movement followed by operation of said stemduring rotation in forward direction to complete the resetting operation, said disc having an arcuate slot therein into which said stem projects and defining three control positions, one said control position being established when said armature is disengaged, the second said position being established upon completion of the resetting operation, and the third said control position being established only if said armature remains engaged when said rotatable means is returned in reverse direction from the second control position.

16. A safety control for fuel burners having main and pilot burners comprising a casing having a valve seat therein provided with a duct communicating with the pilot burner, a valve member engageable with one side of said seat and adapted to control flow of fuel to both the main and pilot burners, means for biasing said valve member to closed position, an electromagnetic device having an armature spaced from said valve member and movable between attracted and released positions, a stem for operating said armature and valve member and projecting beyond said casing, thermoelectric means exposed to a flame at the pilot burner for energizing said electromagnetic device, means carried by the projecting end of the stem for limited slidable move- 'ment thereon, means operatively engageable by said slidable means for movement into engagement with the opposite side of said valve seat to interrupt the flow therethrough, manually rotatable means offset from said stem and adapted for rotation in forward and reverse direction, spring means for returning said rotatable means in reverse direction when manual operation in forward direction is terminated, a cam disc carried by said rotatable means and movable into engagement with said slidable means for effecting said limited slidable movement followed by operation of said stem during rotation in forward direction to complete the resetting operation, said disc having an arcuate slot therein into which said stem projects and defining the 011" "Light pilo and On positions, said "011 position being established when said armature is disengaged, said Light pilot position being established upon completion of the resetting operation, and said On" position being established only if 'said armature remains engaged when said rotatable means is returned in reverse direction from said "Light pilot" position.

HAROLD W; RICE. GEORGE B. SOLOVIEFF.

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

' UNITED STATES PATENTS Number Name Date 2,201,398 Grayson May 21, 1940 v 2,297,854 Alfery Oct. 6, 1942 2,351,277 Mantz June 13, 1944 2,257,024 Ray Sept. 23, 1941 2,333,261 Mantz Nov. 2, 1943 2,361,945 Jackson Nov. 7, 1944 2,397,718 Ray Oct. 6, 1942

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