US 2628677 A
Description (OCR text may contain errors)
Feb. 17, 1953 c. K. sTRoBEL 2,628,677
SAFETY CONTROL AND IGNITION APPARATUS FOR GASEOUS FUEL BURNERS Filed DeC. 6. 1947 HTTOENEY.
Patented Feb. 17, 1953 SAFETY CONTROL AND IGNITION APPARA- TUS FOR GASEOUS FUEL BURNERS Charles K. Strobel, Pittsburgh, Pa., assigner to Robertshaw-Fulton Controls Company, Youngwood, Pa., a corporation of Delaware Application December 6, 1947, Serial No. 790,204
This invention relates to safety control and ignition apparatus for gaseous fuel burners and, more particularly, to electrically operated apparatus for oven burners independent of commercial current supply.
In copending application Serial No. 620,320 filed October 4, 1945, there is disclosed a flashtube ignition system embodying a thermoelectric safety device. The system is placed in operation by manipulation of the oven gas cock which may include a thermostatic device for control of oven temperatures. Such devices are disclosed in Weber Patent No. 2,303,011 as requiring an axial motion of the dial or handle prior to the rotary motion thereof which moves the cock to open position. In the copending application the rotary motion is made use of to operate a pullwire arrangement during the starting period by which a thermal timing device is positioned to determine such period.
An object of the present invention is to render such apparatus more useful by eliminating objectionable torques due to the pull-Wire arrangement.
Another object of the invention is to insure positive operation of the apparatus whenever a starting period is initiated.
Another object of the invention is to simplify the mechanism and, incidentally, to improve the operation of the flash-tube ignition portion of the apparatus. 1
Another object of the invention vis to locate various parts of the apparatus in low ambient temperature zones to lengthen the useful life and improve the general performance.
Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawing wherein Fig. 1 is a somewhat schematic plan View, shown partly in section, of a safety control and ignition apparatus for an oven burner embodying the invention; Fig. 2 is an enlarged view of a detail; and Fig. 3 is a sectional vievnT taken on the line III-III of Fig. 2.
Referring `more particularly to the drawing, the safety control and ignition apparatus is shown with a cooking range having the usual oven burner I and top pilot burner I2 located remotely from the oven burner III, tomary in equipment of this nature,the various burners receive fuel from the rmanifold I4 connected to a source of fuel supply. In this embodiment, the top pilot burner l2 is connected by a pipe I 6 to the manifold I4 and is of the constant burning type. Y j
The main Oven burner l0 is connected to a As is cus-v main fuel pipe I8 in which the fuel supply is under control of a combined main fuel valve and thermostat 20 of the type disclosed in the aforementioned patent to Weber. As structures of this nature are well known, only the essential portions thereof will be described herein and reference may be had to the patent, if desired, for further details. The combined valve and thermostat 20 comprises a main casing 22 Within which a tapered valve member or cock 24 is adapted to rotate. The valve member 24 is hollow and is provided with a port 26 in its side wall adapted to register with an inlet opening 28 formed in the main casing 22. A pipe 29 serves to connect the inlet 28 with the manifold I4 for supplying fuel to the interior of the valve member 24 when the latter is in open position.
Rotation of the valve member 24 is effected by the provision of a reduced stem 30 which projects from the larger end of the valve member 24 into an end casing or cover 32 secured to the main casing 22. A dial or handle 34 is mounted exteriorly of the cover 32 on a tubular projection 36 which fits closely in the cover 32 and is spaced from the stem 30. The projection terminates at its inner end Within an annular recess 38 formed in the main casing 22 adjacent the larger end of the valve member 24. A sleeve 40 is slidably mounted Within the projection 36 and is provided with an end flange 42 which enters a slot 44 in the inner end of the projection 36 and provides means by which rotation of the dial or handle 34 may be imparted to the sleeve 40.
The flange 42 extends radially beyond the projection 36 into engagement with a slot 46 formed in the cover 32 opposite the annular recess 38, the arrangement serving as will hereinafter be apparent to prevent rotation of the dial or handle 34 until axial movement thereof relative to the valve member 24 sufficient to move the sleeve 40 from a retracted position and release the flange 42 into the recess 38-has occurred.
The end of the sleeve 40 opposite the flange 42 is provided with a plurality of oppositely disposed tongues 48 Which project therefrom into complemental slots (not shown) formed in the outer surface of a collar 50 secured to the end of the valve stem 30. That portion of the valve stem 30 which is located Within the sleeve 40 is preferably reduced in diameter forming a shoulder 52 in which one end of the coil spring 54 abuts. The opposite endofv the spring 54 abuts a plurality of projections `56 formedjon the sleeve 40 and located intermediate the ends thereof and serves to bias the sleeve 40 to its retracted position.
The valve stem 30 is provided with an operating shaft |30 connected by a pin and slot connection G2 to an extension 6I which projects through the main casing 22. The opposite end of the extension 6I carries a reoiprocable valve member B4 cooperable with an annular valve seat 65 formed in the casing 22. A projection 68 on the valve member 64 has threaded engagement 'with a nut 69 located within an end casing l0. The nut 69 is anchored to the end casing l0 in such manner as to permit relative axial movement while preventing relative rotation therebetween. Due to the connections described, it is apparent that rotation of the dial 34 will not only rotate the main valve member 24 but will also position the valve member 64 relative to its seat 5S.
The end casing 'l0 is provided with an outlet l?. for passage of fuel from the inlet 28 when the main valve member 24 and valve member 64 are both in open position. In order that fuel may flow to a pilot burner 14 for the main burner |0 whenever the valve member 64 is closed, a passage T6 is formed in the main casing 22 intermediate the valve members 24 and 64 for this purpose. sage 'IS with the pilot burner 14. As will hereinafter be explained, the pilot burner 14 may be dispensed with if desired.
rlhermostatic means for operating the valve member 64 include a diaphragm element S6 positioned within the end casing in operative engagement with the projection 68 and having the usual capillary tube 82 and bulb element 84 associated therewith. The bulb element 64 may be located in the oven or other chamber being heated by the main burner I0. When the bulb member 84 responds to the temperature indicated on the dial 34, then the diaphragm element will be suiciently expanded to seat the valve member 64 on its seat 66 against the bias of a coil spring S6 which is operative between the valve member 64 and the end of the main valve member 24.
The now of fuel in the pipe I8 to the main burner I0 is also under the control of a thermomagnetic control device designated generally by the reference numeral 88. This thermomagnetic control device d8 is interposed in the main fuel pipe IS in proximity of the top pilot burner l2 between the combined main fuel valve and thermostat and the oven burner I0. The control device comprises a casing 90 having an inlet connection 92 extendingthrough the side wall thereof adjacent one end and communicating with an axial main fuel chamber 84 therein. The main fuel chamber 94 is provided with a partition 06 having an axial opening 98 through which fuel may flow from the inlet 92 to an outlet |00 formedV in the wall of the casing 90 at the opposite end of the chamber 94. The inlet 92 and outlet |00 serve as connections for opposite ends of the fuel pipe |8 as will be apparent.
The passage 98 is controlled by a safety valve member |02 which is movable into and out of enga-gement with a valve seat formed on the side of the partition 96 adjacent the inlet opening 92. The valve member |02 is secured to a valve stem |04 which extends through the opening 98 and has slidable engagement with a closure disc |06 which seats on the opposite side of the partition 96. The purpose of the closure disc |06 is to interrupt the iiow of fuel through the passage 98 when the valve member |02 is moved out of engagement with its seat during the resetting operation to be described hereinafter.
The closure disc |06 is reduced opposite its A pipe 18 serves to connect the paS- y thereof.
seating area to slide within an annular projection or housing |08 on the bottom of the chamber' 94. A coil spring I I0 is carried by the reduced end of the closure disc |06 and is operative between the housing |08 and an abutment ||2 formed on the reduced end. It should be observed that when a force is applied to the abutment ||2 to move the closure disc |06 into engagement with its seat, the coil spring I0 will be compressed. When the force is removedy the bias of the spring |l0 will serve to return the closure disc |06 to its open position relative to the seat. However, a yieldable connection is also provided between the closure disc |06 and the valve member |02 to permit relative movement therebetween and this connection forms an override mechanism which includes a coil spring ||4 housed within an axial recess projecting from the closure disc |06 into the reduced end thereof and being operative between the bottom of the recess and the end of the valve stem |04.
The end of the casing adjacent the inlet 02 is provided with a closure cap |6 having a magnet housing I|8 closely engaging the inner wall The closure cap |I6 at its outer end embodies a threaded terminal connection |20. The magnet housing IIO supports a horseshoe magnet |22 which is provided with the usual winding |24 having one end grounded on the closure cap ||0 and the opposite end secured to the terminal connection |20. The valve stem |04 projects into the magnet housing |8 and the electromagnetic device is completed by the provision of an armature |26 which is carried by the valve stem |04 for cooperation with the pole faces of the magnet |22.
t should be noted that the armature |26 is normally spaced from the magnet |22 a less distance than the closure disc |06 is spaced from its seat on the partition 96. Thus, after the armature |26 is in attracted position against the pole faces of the magnet |22, the override spring I I4 permits further movement of the closure disc i0 relative to the valve stem |04. When the valve member |02 is fully disengaged from its seat, then the armature |26 is in attracted relation relative to the pole faces of the magnet |22. The valve member |02 is biased to its seat and the armature |26 to its released position by the provision or" a coil spring |28 operative between the valve member |02 and the bottom of the magnet housing ||8.
The control device 38 also includes means to control the i'low of fuel to a ash pilot burner |30 and an auxiliary pilot burner |32. The flash pilot burner |30 is located in the oven compartment adjacent the main burner I0 while the auxiliary pilot burner |32 is located adjacent the top pilot burner I2. Both burners |30, |32 are supplied with fuel by the pipe |34 extending from the control device 88, the auxiliary pilot burner |32 being conveniently connected to pipe |34 by a branch pipe I 36. This fuel is under control of the thermomagnetic control device 88 by con? necton of one end of a pipe |38 to an inlet opening |40 extending through the wall of the casing 90 and having its opposite end connected to the pipe T8. The inlet opening |40 communicates with an auxiliary fuel chamber |42 formed axially of the casing 90 and separated from the main fuel chamber 94 therein by the housing |00. The bottom wall of the chamber |42 is apertured to provide passage for fuel from the inlet |40 to an outlet |44 formed in the wall of the casing 90 on the opposite lside of the' bottom wall and adapted for connection to the fuel pipe |34.
Passage of fuel from the inlet |40 to the outlet |44 is controlled by an auxiliary valve member |46 which is movable into and out of engagement with the apertured bottom wall of the chamber |42 by operation of a valve stem |48 which is secured to the valve member |46 and extends on either side thereof. One end of the valve stem |48 is located in the chamber |42 and terminates adjacent the abutment ||2 with a sealing diaphragm |43 interposed therebetween. Ihe auxiliary valve member |46 is biased into engagement with the apertured bottom wall of the chamber |42 by a coil spring |50 carried on the opposite end of the stem |48 and which is operative between the bottom wall and a collar |5| carried on the valve stem |48. rThis opposite end of the valve stem |46 terminates beyond the collar thereon for operative engagement with a second sealing diaphragm |52.
A reset stem |54 extends from the opposite side of the diaphragm |52 through the bottom wall of the casing 90 and is provided with a button |56 exterior of the casing 90 and by means of which the reset stem |54 may be reciprocated.
The electromagnet comprising the winding |24 and horseshoe magnet |22 is adapted to be energized by current generated from a therrnocouple |58 which is connected by suitable leads to the winding |24 at the terminal connection |20. The thermocouple |58 is located -so that the hot junction thereof will be heated by a flame from i a thermocouple heating burner |66 which receives a supply of fuel from the pipe |34 which also supplies fuel to the ash pilot burner |30. It will be apparent that the thermocouple heating burner |60 and the portion of the pipe |34 beyond the branch pipe |36 could be dispensed with if the ignition pilot burner 14 is arranged to heat the thermocouple |58 and also ignite the main burner I0 and the burner |36 is connected into the supply pipe 18.
A system of flash tubes is provided for igniting the various burners of the apparatus from the constant burning top pilot burner l2. Accordingly, a relatively short flash tube |62 is provided between the constant burning top pilot burner |2 and the auxiliary pilot burner |32, it being apparent that fuel from the branch pipe |36 supplying the auxiliary pilotburner |32 will enter the flash tube |62 and be ignited fromV the constant burning pilot burner I2. `The name so created will be conducted back-through the flash tube |62 and will ignite the fuel flowing from the auxiliary pilot burner |32.
An elongated flash tube |64 is provided between the auxiliary pilot burner |32Uand the flash pilot burner which is remote therefrom. This flash tube |64 serves to Acause ignition of the flash pilot burner |30 in a manner similar to that described in connection with the flash tube |62. In addition, a branch flash tube |66 extends from the fiashtube |64 adjacent the flash pilot burner |39 to the thermocouple heating burner |60 and likewise serves to ignite the fuel owing therefrom. It will be understood that if the burner |60 is dispensed with, then the dash tubes |64 and |56 would be arranged to ignite the ignition pilot burner 14 directly, instead of this burner being ignited from the thermocouple heating burner |66.
The heat of the flame from the thermocouple heating burner |60 onl the thermocouple |58 serves to energize the electromagnet |22, |24
suciently to hold the armature |26 in attracted position but the thermoelectric current so generated is incapable of moving the armature |26 to this attracted position. Hence, resetting means is provided and will now be described.
The control device 88 is provided with a bracket |68 lextending toward the top pilot burner i2 and forming a support for the auxiliary pilot burner |32. 'Ihe bracket |68 is provided with a support |10 upon which a pair of pivoted members |12, |14 are rotatably and separately carried. The pivoted members |12, |14 constitute a latch and have interengaging means thereon for rotating one from the other. Thus, the member |12 is provided with a projection |16 which is adapted to operably engage a complemental projection |18 carried on the member |14. The member |14 is provided with a slotted end opposite the projection |18 thereon and being offset from the longitudinal axis.
Extending between the slotted end |862 and the reset button |56 is a timing device comprising a bimetal element |82 which is retained in position on the reset button |56 by the provision of a transverse slot |84 disposed transversely of the longitudinal axis of the reset stem |54. Pivotal movement of the member |14 is restricted by its alternative engagement with oppositely disposed shoulders |85 formed on the support member |10. As indicated in the drawing, when the reset button |56 is unoperated, the bimetal element |32 occupies a position on one side of and at an angle to the axis of the reset stem |54. In this position, the bimetal element |82 is offset from the auxiliary pilot burner |32 which projects through the bracket |68 substantially midway between the control device 88 and the support |10.
Manually operable safety means for moving the bimetal element |82 and latching member |14 into substantial alignment with the axis of the reset stem |54 are provided and it will be apparent that in such position the bimetal element |82 will be subject to the heat of the flame of the auxiliary pilot burner |32. In the preferred embodiment, the element |82 will be slightly out of alignment with the latching member |14 for a purpose which will more fully appear. In this position the reset button |56 will be forced inwardly relative to the control device 88 to effect the resetting operation. The manually operable means include connecting means between the dial or handle 34 and the pivoted member |12 and takes the form of a connecting rod |66 supportedat one end in an apertured bracket |83 carried by the pivoted member |12 and providing sufficient clearance for rotation of the member |12 during axial movement of the connecting rod |86. An adjusting element for the connecting rod |86 takes the form of a nut |90 threadedly engaging the end of the rod |86 which projects through the bracket |88 and having a bearing thereon for this purpose.
-The opposite end of the connecting rod |60 is pivotally mounted on a third pivoted member |92 intermediate the ends thereof. The `pivoted member |92 is rotatable onv a bracket |64 projecting from the cover 32 and serves with the pivoted member |12 to support the connecting rod |85 in substantially parallel arrangement with the control device 88 and the combined valve and thermostatic mechanism 2B. A tension spring |96 extends between one end of the third pivoted member |92 and a lug |98 formedon the connecting rod |86 for the purpose of returningthe pivoted member |92 to normal position after operation of the resetting device. It will be apparent that the spring |96 would not be essential if sufiicient bias force may be obtained from the pivoted members |12, |14 and the bimetal element |82 to effect the desired result.
As best shown in Figs. 2 and 3, the bracket |94 also supports a slidable key element 200 having an enlarged end 202 engageable with the free end of the pivoted member |62 and carrying on its opposite end a pivotable tooth member 206 engageable with an operating member or pin 204 projecting from the dial or handle 34` The member 206 is here shown as generally cubical in form, having one edge chamfered at 201, and being pivotally mounted on a pintle 209 extending from the key element 200. A lat spring 208 may be secured at one end to the sldable member 200 with its opposite end engaging the pivoted member 206 to bias the same in a clockwise direction, as viewed in Figs. 2 and 3, so that a plane surface 2|| thereof, adjacent the chamfer 201, is normally held in engagement with a plane surface 2|3 formed on the element 200. The pin 204 is located on the dial 34 in such position that the described engagement will occur when the shut-oil cock or valve member 24 is in its full closed position. Thus, upon axial movement of the dial 34 to free the flange 42 from the slot 3R as described herein, which motion is an essential preliminary to rotary motion of the dial 34, the pin 204 will engage the outer face of the pivoted member 206 and the slidable element 200 will be moved axially relative to the bracket |94.
lt will be apparent that rotary motion of the dial 34 will move the pin 204 out of engagement with the pivoted member 206 to thereby free the slidable element 200 foi` return movement to its initial position under the bias of the spring |66. Return movement of the dial 34 to the off position will not be interfered with since, upon such movement, the pin 204 will contact the side of the pivoted member 206 and cause rotation thereof about the pintle 203 against the bias of the spring 208 to permit the flange 42 to be aligned with the slot 38.
In the operation of the device, it may be assumed that the parts are in the position shown in the drawing and that the constant burning top pilot burner |2 is producing a flame. The dial or handle 34 is then pushed inwardly by the operator to release the ange 42 from the slot 46 preparatory to rotating the dial 34 to a desired temperature setting. The initial axial movement of the handle or dial 34 causes the pin 204 and the slidable member 200 to move inwardly also and the slidable member 200 thereupon rotates the pivoted member |92 in a clockwise direction. The connecting rod |86 is thus pulled to the right as viewed in the drawing and the' interengagement of the pivoted members |12, |14 causes rotation of the latter in a counterclockwise direction on the support |10. The end ci the bimetal element |82 which is engaged with the pivoted member |14 is thus caused to move in a clockwise direction whereupon the bimetal element |82 assumes the broken line position shown in the drawing.
The rotation of the bimetal element |82 to the broken line position causes the reset button |56 and stem |54 to be forced inwardly and to be maintained in such position during such time as the bimetal element |82 remains unheated. The diaphragm |52 and the auxiliary valve stem |48 move to the left to open the auxiliary valve member |46. Such movement of the auxiliary valve stem |48 is sulcient to overcome the bias of the spring ||0 and move the closure disc |06 against its seat on the partition 96. The valve member |02 is moved away from its seat on the opposite side of the partition 96 While the armature |26 is moved into engagement with the pole faces of the magnet |22. It should be noted that immediately prior to engagement of the closure disc |06 with its seat the armature |26 has been moved into engagement with the pole faces of the magnet |22 but the closure disc |06 can thereafter be moved into engagement with its seat due to the provision of the override spring H4 between these elements.
While the description of the various movements which occur upon inward movement of the dial or handle 34 may appear lengthy, it will be apparent that only a momentary lapse of time has occurred prior to rotative movement of the dial 34 which now is conducted. In other words, the inward pushing action and subsequent rotation applied to the dial 34 are part of a single manual operation which is continuous. Assuming that the dial or handle 34 is now rotated to a desired temperature setting, then the port 26 in the shut-oil cock or valve member 24 becomes registered with the inlet opening 28 and fuel is supplied by way of the inlet pipe 29 from the manifold 4 to the interior of the valve member 24. Moreover, due to the threaded engagement of the thermostatic valve member 64 with the nut 60, this valve member 64 is now disengaged from its seat 66 a predetermined distance corresponding to the selected temperature setting on the dial 34. Fuel is thus permitted to flow through outlet 12 and pipe |8 to inlet 92 of the control device 86, through the pipe 16 to the ignition pilot burner 14 and also by way of branch pipe |38 to the control device 88.
As the auxiliary valve member |46 is disengaged from its seat, the fuel from the branch pipe |38 passes by way of inlet |40 and outlet |44 to the pipes |36 and |34. The auxiliary pilot burner |32, the flash pilot burner |30 and the thermocouple heating burner |60 are now supplied with fuel, consequently, these burners become ignited from the constant burning top pilot burner |2 by the flash-tube system described. The ignition pilot burner 14 also becomes ignited from the thermocouple heating lburner |60. It will be observed, however, that no fuel can flow to the main burner |0 at this time due to the engagement of the closure disc |06 with its seat and consequent shutting off of now of fuel between the inlet 92 and the outlet |00 of the control device 88.
After a predetermined time-delay during which the bimetal element |82 becomes suiliciently heated by the flame from the auxiliary pilot burner |32, the element warps and trips the latch comprising pivoted members |14 and |12. Since the bimetal element |82 is disposed at an angle to the axis of the member |14 when cold, warping of the bimetal will bring these elements into alignment and cause axial compression of the bimetal element 82. Thus, further warping of the lbimetal element will cause an over center snap action to effect the tripping operation as the compressive forces are released. As the pivoted member |14 is rotated in a clockwise direction when tripped, the bimetal element |82 is rotated in a counterclockwise direction about the slotted end |84 in the reset button |56 as a pivot. The
9 bimetal element |82 is thus moved out of the path of a flame from the auxiliary pilot burner |32 to its initial cold position and simultaneously the force upon the reset button |56 is released. The connecting rod |86 is moved to the left, partly under bias of the spring |95, and at the same time the pivoted member |92 and slidable element 200 resume their initial positions shown in the drawing. It will be noted that the pin 204 has beenrotated with the handle or dial 34 out of operative engagement with the tooth member 206 so that resumption of the initial position of the slidable element 200 is not interfered with. However, the dial 34 is still occupying an inward position and Will maintain such position until the flange 42 on the sleeve 40 can again enter the slot 46. Such entry of the iiange 42 occurs when the dial 34 is returned to the initial off position shown in the drawing and is not effective at this time.
The system has now assumed its steady-state operating' condition. The retraction of the reset stem |54 has caused the auxiliary valve mem-ber |45 to become engaged with its seat to prevent the fiow of fuel from the inlet |40 to the outlet 44 so that the flow of fuel through the pipes |34 and 35 to the flash pilot burner |30, thermocouple heating burner |50 and auxiliary pilot burner i3? is cut off. However, the time for heating the bimetal element |82 sufiiciently to cause it to warp is made long enough so that the thermocouple |55 can become sufficiently heated by the flame from the thermocouple heating burner its to generate current for energizing the electromagnets |22, |24 before the auxiliary valve member |115 is moved to closed position. As the armature |25 is now held in attracted position against the pole faces of the magnet |22, the valve member m2 remains open While the closure disc ict becomes disengaged from its seat under the bias of the coil spring |0. Flow of fuel from the inlet 02 and outlet |00 to the main burner l0 is now permitted. This burner is ignited by the iiame at the ignition pilot burner 14 or where the latter is dispensed with by the flame at the therniocouple heating burner |60.
It has been mentioned herein that the ignition pilot burner 'i4 may be dispensed with if desired. it then becomes necessary for the thermocouple heating burner |50 to be positioned to ignite the main burner it. As the flow of fuel to this burner |50 is cut oi by closure of the auxiliary valve member |48 when the resetting operation is completed and the closure disc |06 has only at that time left its seat, it is also necessary that the unconsumed fuel remaining in pipe |34 after the auxiliary valve member |46 closes be relied upon to continue the flame at this burner until the main burner i is ignited thereby. Moreover, after the thermocouple heating burner |50 ceases operating it will be necessary for the thermocouple |53 to be heated by the flame from the main burner I0. An advantage of the arrangement is that a hundred per cent shut-off of fuel is obtained upon operation of the safety control. Where the ignition pilot burner 14 is employed it is unnecessary to locate the thermocouple |53 to be heated by the main burner flame or to rely upon residual fuel in pipe |34 to ignite the main burner i0. In this arrangement, however, a hundred per cent shut-off is not possible due to the pipe i8 being connected to the combined valve and thermostatic device ahead of the control device 88.
If at any time during the operation of the apparatus the thermocouple |58 ceases to be heated by the iiame from the ignition pilot burner |4 or the main burner I0 where the ignition pilot burner is dispensed with, then the armature |25 will be released from the pole faces of the magnet |22 causing the valve member |02 to become engaged with its seat and prevent flow of fuel to the main burner |0. The dial or handle 34 may be operated in a coun'terclockwise direction to its original off position upon termination of the oven burner operation. During this return movement of the dial 34 the pin 204 will engage and rotate the toothed member 20G so that the return movement is not interfered with. y
It will be apparent that an automatic means of resetting a thermornagnetic safety device has been provided and is operable by merely manipulating the usual knob of a fuel cock from off to on position or to a desired temperature setting where a combined thermostat and fuel cock 2i) is provided. A positive rod connection operated by a push action has been substituted herein for the less reliable pull-wire operated by rotary motion as in the copending application.
It will be appreciated that, for most gas ranges, the desirable location of the safety device is directly in line with the range thermostat which is centrally disposed on the front of the range. The safety device is thus positioned in the rear section of the range while the partition between the oven and utility compartments provides a convenient mounting for the oven flash tube. The safety device with its valves and other movable parts is operated at relatively low ambient temperatures. If the oven ash tube terminates at the auxiliary pilot burner then the top bend of this flash tube is quite short or entirely eliminated to improve oven flashing. Terminating the oven iiash tube at the auxiliary pilot burner also results in one less flash tube than is necessary in prior devices at the location of the constant burning pilot burner. The congestion of parts at this location is thus relieved.
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 drawings are intended by way of illustration only and are not to be construed in a limiting sense.
1. A contro1 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, operating means for rotating said valve between said positions, means for securing said operating means in relative nonrotatable but axially movable relation with said valve, Safety shut-oil` means operable between positions for controlling the fuel supply to the burners and being located remote from said main valve, and connecting means between said operating means and said safety means and operable upon said axial movement for positioning said safety means to supply fuel to the pilot burner, said connecting means including a timing device responsive to a iiame at the pilot burner for returning said connecting means to an inoperative position.
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, operating means for rotating said valve between said positions, means for securing said operating means in relative 'non-rotatable but axially movable relation with said valve, safety shut-off means operable between positions for controlling the fuel supply to the burners and being located remote from said main valve, a latch, a connecting rod between .said latch and said main valve and operable upon said axial movement for effecting operation of said latch to a latching position, and a bimetal element between said latch and said safety means and movable for resetting said safety means to supply fuel to the pilotburner upon said latching operation, said bimetal element being moved by said latching operation into the path of a flame at the pilot burner, said element becoming warped when heated by said flame for movement out of said path and simultaneously releasing s aid latch for terminating the resetting operation. i l y f3. A control apparatus as claimed in claim 2 wherein said latch comprises a pair of pivoted o nesaid member being rotatable by said connect- 4ing rod for causing rotation of the other said member to saidnlatching position, said other member operatively engaging Vsaid bimetal element for moving the same for resetting said safety means to supply fuel to the pilot burner and for 'moving s'aid element into the path of said flame `and being thereafter rotated by warping of said element when heated by said flame to release said latch and terminate the resetting operation.
` '4. A'safety control apparatus for fuel burners having a main burner, a pair of pilot burners and "a source of fuel supply, comprising a main shutoff valve rotatable between positions for controlling the fuel supply to the burners, operating `means for rotating said main valve between said positions and being adapted for initial axial movement relative thereto, safety valve means operable betweenvopen and closed positions for controlling the supply of fuel to at least the main 12 burner, electromagnetic mansoperati'vely ciated with said safety valve means for holding the same in open position when energized, thermoelectric means responsive to the heat of a flame at on'e of the pilot 'burners for energizing said electromagnetic means, and yresetting vmemos operative for positioning vvsaid safety valve means in said open position, said resetting means including a pair of pivoted members positioned intermediate said main valve and said safety valve means and having interengaging portions thereon, a third pivoted member rotatable by said operating means upon said axial movement thereof, a connecting rod between said third pivoted member and one of'said pair of pivoted members, and a bimetal element located adjacent thefother pilot burner and extending between said safety valve means and the other Ione of said pair o'f pivoted members, the arrangement being such that said axial movement 0f said operating'means causes movement of said bimetal element into the path of a flame at said other pilot burner and simultaneous movement of said safety valve means tc open position, said bimetal element thereafter warping to its initial position while said electromagnetic means holds said "safety valve means in said open position.
CHARLES K. STROBEL.
REFERENCES CITED The following references are of record in the le of this patent:
UNITED STATES PATENTS Number Name Date 2,049,958 Jones Aet al Aug. 4, 1936 2,049,959 Jones et al. Aug. 4, 1936 2,063,834 Bast et al. Dec. 8, 1936 2,318,823 Wantz May 11,1943 2,478,386 Gauger -1 Aug. 9, 1949 2,483,191 Gauger Sept. 27,1949