US3045689A - Gas oven control - Google Patents

Description

GAS OVEN CONTROL 3 Sheets-Sheet l Filed July l5. 1959 July 24, 1962 J. H cANTLlN ETAL 3,045,689

GAS OVEN CONTROL s sheets-511661 2 Filed July l5, 1959 INVENTORS JOHN H. CANTLIN AUGUST J. HILDENBRANDT ATT NEYS July 24, 1962 J. H. cANTLIN ETAL 3,045,589

GAS OVEN CONTROL Filed July l5, 1959 5 Sheets-Sheet 5 FIG.5

INVENTORS JOHN H. CANTLIN AUGUST J. HILDENBRANDT ATTOR YS United Sta s 3,045,6529 GAS OVEN CONTROL John H. Cautlin, Short Hills, and August J. Hildenbrandt, Scotch Plains, NJ., assiguors to The Wilcolator Company, Elizabeth, NJ., a corporation of Delaware Filed July 15, 1959, Ser. No. 827,283

7 Claims. (Cl. 137-66) The present invention relates to gas oven controls, and more particularly to improvements in such controls with respect to safety features, enabling an oven or other burner to be started and operated without danger of explosion.

It has been proposed heretofore to provide in association with gas burners, safety valve means, responsive to the absence of heat from a gas flame, to shut off the supply of gas to the burner. A common form of such safety means comprises a sensitive, solenoid-operated valve element, the magnetic coil of which is connected to a thermocouple device positioned in the vicinity of the gas burner or the pilot burner therefor. 'Ihe valve element is spring-urged to a closed position, but can be opened, by manual or other means, to permit the flow of gas to the pilot or other burner. The burner is started by ternporarily holding open the safety valve and lighting the gas flame. As soon as the thermocouple element becomes heated, the small flow of current through the solenoid means provides sufficient magnetic force to overcome the spring force on the valve plunger, so that the valve remains open as long as the flame is burning. Normally, the thermocouple element is positioned adjacent a pilot Iflame, so that turning the main flame on or off does not affect the safety valve.

In accordance with the present invention, an improved gas control valve is provided, which includes an automatic shut off valve as generally described above and which incorporates, in combination therewith, additional novel and desirable safety features. One such feature lcomprises a novel and improved arrangement for controlling the flow of gas to a pilot burner in accordance with the solenoid controlled main safety valve. In this respect, in the control device of the invention, a main gas safety valve is located between the main `gas control valve and the main gas outlet, leading to a gas burner. A pilot gas line passes around the main control valve and also, therefore, around the main gas safety valve. Adjacent the main gas safety valve, there is provided a pilot gas safety valve having an element movable between open and closed positions. To actuate the pilot gas safety valve, a lever is mounted within the valve housing, in position to engage the movable valve elements of both the pilot gas and main safety valve. The arrangement is such that the pilot gas safety valve is caused to open or close along with the main safety valve. Accordingly, should the main gas safety vlave close, as a result of loss of flame at the pilot burner, the further flow of gas to the pilot burner will be discontinued immediately.

As one of the specific features of the invention, an improved actuating linkage, including a lever and a spring, is provided for actuating the pilot gas safety valve. In this respect, the spring is arranged to act upon the lever in a direction tending to close the pilot gas safety valve and at the same time to urge the main gas safety valve to a closed position. However, the relative orientation of the spring and lever is such that, when the main gas safety valve is moved to an open position, the spring and lever are disposed substantially in dead-center relation, so that little effective force is applied to the lever. Accordingly, when the main gas safety valve is open, the lever applies little effective force to the main valve element, and the latter readily can be maintained in an 3,@4589 Patented `Iuly 24, 1962 open position by a thermocouple-energized solenoid therefor. On the other hand, as the main safety valve element moves toward a closed position, in response to loss of flame at the pilot burner, the spring applies an increasing force on the lever, causing the pilot valve to be seated firmly on the cooperating valve surface. The described arrangement is advantageous, in that effective sealing by the pilot gas valve element may be accomplished by spring means which exert a minimum force upon the main gas valve element when the pilot valve is in an open position.

In accordance with another specific feature of the invention, improved and simplified means are provided for preventing lighting of the pilot burner under conditions in which gas is available at the main burner. In this respect, the main gas control valve of the invention comprises a rotatable control member, by which the flow of gas to the main burner may be turned on and off and regulated. An appropriate knob is affixed to the outer end of the rotatable member for manual manipulation in the usual manner. In accordance with the invention, however, the knob, which is removable from the rotatable member, conceals and prevents access to a manually actuated element used for opening the main gas and pilot gas safety valves. In order to obtain access to such element, which may be referred to as a resetting element, the knob must rst be removed from the rotatable member. However, in accordance with the invention, novel and improved means are provided which prevent removal of the knob when the rotatable member is in other than an off position. In addition, the rotatable member is so shielded that manual access thereto is substantially prevented when the knob is removed, so that it is rendered extremely difficult for unauthorized personnel to rotate the valve member to an open position when the knob is removed. Necessary servicing of the control valve is accommodated, however, by the provision of means whereby trained service personnel may operate the rotatable control element readily, even with the knob off, to effect desirable adjustments of the valve.

lFor a better understanding of the invention and for a further description of the above and other advantageous features thereof, reference should be made to the following detailed description and to the accompanying drawings, in which:

FIG. l is a longitudinal, cross-sectional view of a gas oven control incorporating the features of the invention;

FIG. 2 is a side elevation of the gas oven control of FlG. 1, with parts broken away to illustrate certain details;

FIG. 3 is a fragmentary, front elevation of the oven control of FIG. l;

FIG. 4 is a front View of the back section of the control housing, illustrating the actuating mechanism for the pilot gas safety valve;

FIG. 5 is a cross-sectional view taken generally along line 5-5 of FIG. 4; and

FIG. 6 is a fragmentary, cross-sectional view similar to FIG. 5 showing the valve parts in open positions.

Referring now to the drawings, the reference numeral 10 designates generally a valve housing which, in the illustrated device, consists ofl a front part 11, a central part 12, and a Iback part 13. The front housing part 11 has a tapered bore 14 therein, in which is received a complementary valve member 15. The valve member 15 per se may be of known design, having a central longitudinal opening 16 adapted to be connected to a gas inlet (not shown) in the front housing part 11 when the valve member 15 is in any of a series of on rotary positions and to close off the gas inlet when the member 15 is in an off rotary position. The member 15 forms part of a control valve assembly, which is described in greater 'valve 28.

3 detail in the copending application of August I. Hildenbrandt, Jr., et al., Ser. No. 750,231, now Patent No. 2,994,755, filed July 22, 1958, for Gas Oven Control.

Brieily, the gas control valve comprises a threaded valve stern 17 whose splined end portion is received in a slotted adjusting member 18. The adjusting member 18 is rotatable with respect to the main valve element 15, but is normally held in fixed position by frictional means, including washers 19 and a spring 20.

A sleeve 21 fits over the rod 17 and seats, on its spherically contoured outer end, a valve element 22, which is adapted to cooperate with a valve seat 23 on the front housing part 11 and constitutes the main gas control valve of the complete unit. The initial open position of the valve element or disc 22 may be set by rotating the valve element to advance the threaded rod 17 in its threaded socket 24. This permits the flow of gas into the chamber 25, formed in the central housing section 12 and, under normal operating conditions, to a gas burner (not shown) through a gas outlet conduit 26.

In the area supplied with heat by the gas burner, there is positioned a suitable bulb (not shown) filled with expandable liquid and, in response to heating of the bulb, liquid is forced into a diaphragm member 27, to expand the member and move the valve 22 to its closed position. The distance to which the valve disc 22 is initially moved away from its seat 23 by rotation of the valve element 15 determines the amount of bellows or diaphragm expansion required to close the valve and hence the temperature at which the valve closes.

In the illustrated valve, a main gas safety valve 28, comprising a solenoid coil 29, a valve plunger 30 and a spring 31, is mounted in the back housing part 13, substantially as shown in FIG. 1. The valve plunger 30, which is urged in a lforward direction by the spring 31, cooperates with a valve seat 32 on the central housing part 12 to close off the main gas passage 33 connecting the chamber and the main gas outlet 26. In accordance with known practice, the solenoid 29 is adapted to be actuated by a very small electric current generated by a thermocouple 34 positioned adjacent a -pilot burner 35. Thus, when the burner 35 is on, the solenoid 29 is energized and the valve plunger 30, which may be considered the main gas safety valve element, is held open, against the action of the spring 31, to permit the flow of gas to the outlet 26 and to the main burner of the heating device.

In accordance with usual practice, manual means are provided to effect the initial opening of the safety valve, follo-Wing which the pilot burner 35 may be ignited and, after the thermocouple 34 has heated sufciently, the plunger will be retained in a retracted position by the energized solenoid 29. Although certain aspects of the manual means for opening the valve plunger 30, constituting part of the present invention, will be described later in more detail, it may be noted, at this time, that a rod-like element 36, sometimes referred to as a resetting element, is mounted slidably in the housing parts 11, 12 and has an end portion positioned opposite the end of the valve plunger 30. A spring 37 acts against the enlarged head portion 38 of the resetting element, to urge the element forwardly, to a retracted position. Opening of the main gas safety valve is effected by pushing the resetting element 36 inward, so that the end of the element engages the valve plunger 30 to move it to its retracted or open position. The resetting element 36 is maintained in a depressed posit-ion until the solenoid 29 is sufiiciently energized by the flame of the pilot burner to retain the plunger 30 in its retracted position.

In accordance with one of the specific aspects of the invention, the improved gas oven control incorporates a novel arrangement yfor actuating a pilot gas safety valve in accordance vwith operations of the main gas safety In the illustrated device, pilot gas is supplied from the main source through a passage 40 (FIG. 2) in the front housing part `11. The passage 40 is connected by a passage 41 and by a passage 42 in the central housing part 12 to a filter chamber 43 having mounted therein a lter cartridge 44. The cartridge 44 may be of conventional design and serves to filter impurities from the pilot gas before allowing the gas to flow through a passage 45 to an adjusting valve 46 and then through passages 47, `48 to a passage 49 in the back housing part 13. The passage 49 is generally horizontal, as shown in FIG. 5, for example, and connects with a vertical passage 50 leading to a pilot gas safety valve chamber 51. An outlet passage 52 leads from the chamber 51 to a pilot gas outlet connection 53, to which a suitable fitting 54 (FIG. 2) is applied to connect a pilot gas line 55.

Advantageously, the chamber enclosing the filter cartridge 44 is provided with an optional outlet, not specifically shown, 4whereby a portion of the supply of filtered pilot gas may be utilized for the operation of additional pilot burners incorporated in `an appliance. This may be accomplished readily since, as a general rule, the capacity of the filter cartridge is greater than that required for a single pilot burner. The provision of an optional outlet for filtered gas enables additional pilot burners to be connected to the gas supply without requiring the installation of additional filtering means.

The improved pilot gas safety valve comprises a flexible diaphragm `56 having a plunger 57 mounted in its center portion and urged to an open position, away from the inlet to the passage 52, by a spring 56. Thus, as will be observed in FIGS. 5 and 6, when the diaphragm 56' is moved to the right the passage 52 is closed off, preventing the ow of pilot gas to the pilot gas line 5'5. When the diaphragm is moved to the left, as shown in FIG. 6, a free ow path is provided connecting the passages 50 and 52.

To actuate the valve plunger 57 and diaphragm 56, there is provided a lever 58 pivoted along a knife edge 59 by a bracket 60 mounted on the housing part 13. The bracket 60 is secured to the housing by screws 61 and has tabs `62, bent outward to form pivot seats for the lever, `and a tab 63 bent outward at the top to provide an anchor for a spring 64. The lever 58 has a forked lower end yforming arms `65, 66 spaced apart a `distance sufficient to straddle the spring 31 of the main gas safety valve and having curved end portions 67 adapted to bear against the back face of the valve plunger 30, substantially as `indicated in FIG. 5.

Above lthe pivot edge 59, the lever 58 has an arm portion 68 extending upward and positioned to overlie the end of the pilot gas valve plunger 57. Thus, it will be observed that ythe pilot gas safety valve is closed by clockwise pivot-al movement of the lever 58 and opened by counterclockwise pivotal movement of the lever.

To urge the pilot gas valve normally to a closed position, `the spring 64 is anchored at one end by the bracket tab 63 and engages at its other end the lever 58, at a point below 4the pivot edge 59. The arrangement is such that the spring 64 tends to pivot the lever 58 in a clockwise direction. In accordance with one of the specific features of the invention, however, the spring 64 and lever 58 are so oriented and arranged that, when the lever 58 is pivoted counterclockwise, permitting the valve diaphragm 56 to open against the pressure of the gas, the force of the spring is applied along an axis nearly intersecting the pivot axis of the lever. The spring and lever assembly being thus very close to dead-center position, the spring 64 applies very little effective pivoting force to the lever, so that the lever is held easily in an open position.

When a burner regulated by the new control is rst started, the main gas safety valve plunger 30 is moved manually to its retracted position, or to the right, by the resetting element 36. The force of the spring 64 is readily overcome by the manual actuation of the resetting ele,-

ment 36, and thel plunger 30 and lever 5S are moved to the positions illustrated in FIG. 6, in which the spring 64 and lever 'are substantially in a dead-center relation. The plunger 30 is held in its retracted position, manually, until suicient heat is generated by the pilot burner to energize the solenoid 29. A-t that time, the manual force may be released from the resetting member 36, as the magnetic force ofthe solenoid 29 is sufficient to overcome the action of the spring 31 and the slight additional force applied by the spring 64. Further, in this respect, i-t will be noted that the spring 64 engages the lever 58 at a point 69 quite close to the pivot axis, so that the relative leverages of the spring 64 and the solenoid 29 substantially favor the solenoid.

I-f, for any reason, both the pilot and main burners experience a loss of ilame, the solenoid 29 is deenergized, releasing the plunger 30 and permitting its return by the yspring 31. At this time, the lever 58 pivots clockwise, under the action of the spring 64, lto carry the valve diaphragm 56 to its closed position. The closing force of the spring 64, which is at a practical minimum when the plunger 30 is retracted, increases progressively as the pilot valve diaphragm approaches its closed position. Accordingly, substantial force is available for maintaining the pilot gas safety valve tightly closed. The lever 58 `also assists in urging the main gas plunger 30 toward its closed position. However, when both the safety valves are closed, a slight clearance is provided between the legs 65, 66 of the lever and the head `of the plunger 30, so that the full force of the spring 64 is brought to bear on the pilot gas valve diaphragm 56.

As noted, in order to initiate operation of the pilot burner 35, i-t is necessary to depress manually the resetting element 36. To avoid accidents due to carelessness it is desirable to provide means to prevent the ow of gas to the main burner prior to or during the lighting of the pilot burner. To this end, the improved control includes novel and improved arrangements for preventing manual access to the resetting element 36 except when the main gas control valve is in an off position and for preventing the accidental turning `on of the main gas valve during the lighting operation.

In the illustrated control valve, the main gas control member 15, which is rotatable in the housing part 11 to effect control of the flow of gas, has a portion projecting forwardly from the housing part 11, .and this projecting portion is conveniently engaged for manual operation of the valve. In accordance with one aspect of the invention, the projecting portion 15 of the rotatable valve mem-ber 15 is substantially entirely surrounded by a close fitting shield 70, which is secured to the housing part 11 by means of screws 71, for example. The shield 76 extends forward along the rotatable valve member 15, substantially to its forward end, lso that it is difficult `to obtain manual access tothe valve member in order to rotate it, particularly since there is a certain amount of friction between the valve member and the surrounding housing part A11. In addition, for purposes to be described, there is provided at the forward end of the shield 70 an inturned lip 72, `which extends in toward the projecting portion 15 of the valve member. The lip 72 forms an opening in the end of the shield, the diameter of which is only slightly greater than that of the projecting portion 15 of the valve member.

For .rotating the valve member 15 there is provided a knob assembly, including -a knob 73 and a -sleeve 74 secured thereto. The outer diameter of the sleeve 74 is smaller Ithan the opening formed by the lip 72 of the shield 70 and slightly larger than the diameter of the projecting portion 15 of the valve member, whereby the sleeve may be received frictionally over a thin sleeve 75, `which is secured to the projecting portion 15' and forms, in effect, an integral part thereof. As shown in FIG. l, the fixed sleeve 75 has a tab 76 bent outwardly therefrom `for reception in a slot 7'7 formed in the knob sleeve 74. Thus, when the sleeve 74 is applied over the sleeve 75, with the slot 77 aligned with the Itab 76, the knob 73 and the valve member '15 are locked against relative rota-tion and the valve member may be manipulated readily by rotation of the knob.

Manual access to the resetting element 36 is normally prevented by the knob 73, which has a wide skirt portion 78 disposed radially outward of the knob 38 `of the resetting element. Thus, when the knob is assembled with the valve member 15, the knob 38 is substantially enclosed and access thereto is difficult if not impossible.

To assure that the resetting element 36 is accessible only when the valve member 15 is in an off position (at least lto untrained personnel) means are provided for preventing removal of the knob 73 when the valve member l5 is in any position other than the off position. To this end, the knob sleeve 74 is provided with an outturned tab 79 `which extends radially beyond the inner edges of the inturned lip 72 of the shield 70. A notch or slot t) is provided in the lip 72 to permit the entry of the tab '79 only in one position, that being the one in which the rotary valve member 15 cuts off the gas supply to the chamber 25 and gas outlet 26. Thus, to provide access to the resetting element, it is first necessary to rotate the 4knob 73 to -an off position, after which the knob may be withdrawn axially, the tab 79 passing through the notch Sti, to expose resetting element. When the knob is thus removed, accidental turning on of the valve member 15 is virtually precluded by the shield 70 and, further, it is extremely diliicult `for an untrained person even to rotate the valve member 15 by intention.

To enable trained service personnel to perform necessary adjustments, repairs, etc., -a slot 81 may be provided in the outer end of the projecting portion 15' of the valve member. The slot thus provided may be engaged by a screw driver or other implement to effect rotation of the valve member 15, even though the knob 73 has been removed.

The new control valve assembly is advantageous in that it incorporates Va number of highly desirable safety features, yet is of a generally simplified nature, capable of economical manufacture in large quantities. It should be understood, however, that the specific form of the invention herein illustrated and described is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the Ifollowing appended claims in determining the full scope of the invention.

We claim:

l. In a gas burner control including a housing having a gas inlet, a main gas outlet, means forming communication between said inlet and outlet comprising a main gas iiow port, a pilot gas outlet, means forming communication between said gas inlet and said pilot gas outlet comprising a pilot valve port, a valve member movable to and from said main gas ofw port to close and open said port, means Ito move said valve member to and from said main valve port, a pilot valve member movable to and from said pilot valve port, means to move said pilot valve member including a pivoted lever interconnecting said valve members whereby movement of said main valve member to its port opening and closing positions control movement of said pilot valve member to its open and closed positions respectively, and spring means operatively connected with said lever and normally urging said lever about its pivot .for urging said pilot valve member toward its port closing position, said spring -means being located relative to said lever to reduce the rotative force thereof on said lever as said lever moves in a direction to control said pilot valve to move toward its port opening position and to substantially increase said force on said lever to urge said pilot valve member to close on its port when said lever moves to close said pilot valve member on its port.

2. A gas burner control as defined in claim l in which said main gas valve member comprises a solenoid operated plunger, and `second spring means urging said main gas valve member toward its port closing position, said lever being operatively connected with said plunger whereby the first mentioned spring means -acting on said lever urges said plunger toward its port closing position.

3. A gas burner control as defined in claim 2 in which said plunger has an enlarged, generally circular head, said second spring means acting on said head, said second spring means 4being generally cylindrical in form and of smaller diameter than said head, and said lever having a forked end straddling said second spring means and engaging said head on opposite sides of said second spring means.

4. In a safe lighting gas oven control of the type including a housing having a main gas port, a control valve member cooperating with said port, means to actuate said control valve member rela-tive to said port, a main gas safety valve port, a safety valve member cooperating with said safety valve port, safety responsive means to hold said safety valve from its port, and manual reset means for removing said safety valve member from its port, the improvement characterized by said means to actuate said control valve member comprising a rotatable member projecting from said housing for controlling operation of said control valve member including closing thereof on said main port when said rotatable member is in one control position, a shield substantially surrounding the portion of said rotatable member projecting from said housing to prevent manual access thereto, from the sides thereof, said shield being open at the outer end, said manual reset means having a manually operated portion thereof disposed adjacent to said shield, a removable knob assembly having a drive portion extending between said shield and said rotatable member and drivingly engaging said rotatable member for rotation thereof, said knob assembly having an annular skirt overlying said open end of said shield and said manually operable portion of said reset means to substantially prevent access to said manual reset means, and means locking said knob assembly to said rotatable member in all rotary positions of the latter eX- cept the off position in which said main control valve member is closed on its seat.

5. A gas oven control as defined in claim 4 in which the last mentioned means comprises an in-turned flange on said shield and closely surrounding said rotatable member, said ange having a notch therein, and said knob assembly including a sleeve adapted to be inserted between said shield and rotatable member and having a tab projecting radially outwardly and preventing insertion or removal of said sleeve except when said tab and notch are aligned, said sleeve and rotatable member having interengaging means preventing relative rotation when said sleeve is inserted over said rotatable member.

6. A gas oven control as defined in claim 4 in which said rotatable member has a slot in its end substantially recessed within said shield and providing for rotation of said rotatable member by means such as a screw driver when said knob assembly is removed.

7. ln a safe lighting gas oven control of the type including a housing having a main gas port, a control valve member cooperating with said port, means to actuate said control valve member relative to said port, a main gas safety valve port, a safety valve member cooperating with said safety valve port, safety responsive means to hold said safety valve from its port, and manual reset means for removing said safety valve member from its port, the improvement characterized by said means to actuate said control valve member comprising a rotatable member rotatable throughout a range for operation of said control valve member and including an angular position in which said control valve member is closed on said main port, said manual reset means having a manually operable portion thereof disposed adjacent to said rotatable member, a knob assembly for rotating said rotatable member, drive means ibetween said knob assembly and rotatable member comprising tongue and groove means to permit axial movement of said knob assembly relative to said rotatable member and to lock said knob assembly in rotatable driving relation with said rotatable member, said knob assembly including an annular portion overlying said manually operable portion of said reset .means to prevent ready access thereto when said knob assembly is drivingly connected with said rotatable member, means to lock said knob assembly with said rotatable member, and means to render said locking means ineffective to lock said knob assembly to said rotatable member when said rotatable member and knob are in the valve closing position.

References Cited in the file of this patent UNITED STATES PATENTS 306,568 Wilder Oct. 14, 1884 2,189,663 Grooms Feb. 6, 1940 2,363,073 Mantz Nov. 21, 1944 2,688,974 Sogge Sept. 14, 1954 2,909,219 Matthews Oct. 20, 1959 2,911,152 Weber Nov. 3, 1959

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