US2562536A

US2562536A - Oven control

Info

Publication number: US2562536A
Application number: US107590A
Authority: US
Inventors: Charles M Mayer
Original assignee: TAPPAN STOVE CO
Current assignee: TAPPAN STOVE Co
Priority date: 1949-07-29
Filing date: 1949-07-29
Publication date: 1951-07-31
Anticipated expiration: 1968-07-31

Description

C. M. MAYER OVEN CONTROL July 31, 1951 2 Sheets-Sheet 1 Filed July 29, 1949 INVENTOR. (was: MNayer BY fifty Fat exited July 31, 195i OVEN CONTROL Charles M. Mayer, Mansfield, Ohio, assignor to The Tappan Stove Company, Mansfield. Ohio,

a corporation of Ohio Application July 29, 1949, Serial No. 107,590

12 Claims.

This invention relates generally to automatic oven control systems for cooking ranges using gaseous fuel. More specifically, the invention relates to a system having incorporated therein an electrically operated time control mechanism by which the oven burner is automatically turned on at a predetermined time and after burning for a set length of time is automatically turned off. Systems of this general character are well known and work satisfactorily as long as there is no current failure during their operation. However, in the event of a temporary current failure, some systems are liable to cause overcooking or burning of food in an oven while others are liable to cause undercooking.

The principal object of this invention is to provide in a system of this character means operative to prevent the overcooking or burning of food in an oven in the event of a temporary current failure during cooking.

Another object of the invention is to provide an improved electrically operated oven control system which is so constructed and arranged that food in an oven will be cooked for a set length of time, even in the event of a temporary current failure during cooking.

Another object of the invention is to provide a system of this character which is very efficient in operation and yet is of very simpl construction and is inexpensive to manufacture.

Other and more limited objects of the invention will be apparent from the following specification and the accompanying drawings forming a part thereof wherein:

Fig. 1 is a diagrammatic viewillustrating one form of my invention, with the manually operable main control valve in closed position;

Fig.2 is a detail view showing the manually operable main control valve in open operative po-' sition;

Fig. 3 is a fragmentary vertical section through the normally closed solenoid operated valve by which the operation of the burner is automatically controlled in conjunction with the manually operable valve;

Fig. 4 is a view similar to Fig. 1 showing another form of the invention, with the control valves in inoperative position;

Fig. 5 is a detail view showing the control valves of Fig. 4 set for manual operation of the burner; Fig. 6 is a view similar to Fig. 5 showing the control valves set for automatic operation of the burner; and

Fig. 7 is a fragmentary vertical section through;

the normally closed solenoid operated valve of 2 Fig. 4 by which the operation of the burner is automatically controlled.

Referring now to the form of the invention shown in Figs. 1 to 3 of the drawings, the numeral i indicates the oven of a cooking range using gaseous fuel. Within or below the oven I is a burner 2 to which fuel is supplied from the range manifold 3 through a conduit 4 extending there between. An oven temperature control valve 5, of standard construction, which can be set to maintain the oven at any desired temperature, is interposed in the fuel conduit 4 adjacent the oven I and burner 2. A safety control valve 6 is interposed in the conduit 4 between the manifold 3 and the oven temperature control valve 5. The safety control valve 6 is connected to a constantly burning pilot burner l by a small conduit 8 through which fuel is supplied to the pilot burner after passing through the safety control valve 6. The pilot burner l is mounted adjacent the oven burner 2 in position to ignite the burner when fuel is supplied thereto. A thermostatic element 9 is disposed adjacent the pilot burner 1 in position to be heated thereby while the pilot burner l is burning. The thermostatic element 9 is connected to the safety control valve 6, as indicated at I0, and is provided to maintain the safety control valve 6 open as'long as the pilot burner I is ignited. But in the event the pilot burner I should be extinguished for any reason, the thermostatic element will. immediately cool and cause the safety control valve to close which will completely shut oil the supply of fuel to both the oven burner 2 and the pilot burner I. The pilot burner I cannot be re-ignited except by the manual operation of a button I I which when depressed will admit fuel to the pilot burner I only. The button must be held depressed, after the pilot burner has been re-ignited, until the pilot burner heats the thermostatic element sufliciently for it to reset the safety control valve 6 in open position so that fuel is again normally supplied to both the pilot burner I and the oven burner 2.

. Safety controls of this general type are of well known standard construction. Consequently the safety control valve 6 has not been described in detail herein.

A manually operable valve I2 and a normally closed solenoid operated valve I3 are interposed in the fuel conduit 4 between the safety control valve 6 and the oven temperature control valve 5. As shown in the drawing the manually operable valve I2 is disposed between the solenoid operated valve I3 and the oven temperature control valve 5. However, the position of these valves 3 can be reversed, so that the solenoid operated valve I3 is disposed between the manually operated valve I2 and the oven temperature control valve 5, without afiecting the operation of the mechanism as hereinafter described.

The valve I2 is adapted to be manually opened and closed by an operating handle I4, and the valve I3 is adapted to be opened and held open by a solenoid I5. When the solenoid I5 is deenergized, the valve I3 will close by gravity. The valve I3 comprises a casing I5 having a pair of chambers II and I8 therein which are divided by a partition I9 having an aperture therethrough. A valve seat 2|, in which a valve disc 22 is adapted to seat, is formed about the upper end of the aperture 20. The valve disc 22 is secured to the lower end of a valve stem 23 the upper end of which is suitably secured tothe solenoid plunger 24. When the solenoid I5 is energized the solenoid plunger 24 will lift and hold the valve disc 22 away from its seat 2| and thus provide communication between the chambers I! and I8 through the aperture 29., so that fuel may flow freely from the chamber II into the chamber I8. When the solenoid is de-energized' the valve disc 22 will drop by gravity onto its seat 21 and close communication between the chambers IT and I8 and stop the flow of fuel through the conduit 4.

In both manual and automatic control of the oven burner 2 both the valves I2 and I3 must be open so. that fuel may flow from the manifold 3 to the burner 2 through the conduit 4 and valves I2 and I3. In manual operation the burner 2 is controlled entirely by the manual opening and closing of the valve I2; and in automatic opera,- tion the operation of the burner is controlled through the valve I3, after the valve I2 has been manually opened, by an electrically operated time control mechanism generally indicated by the numeral 25.

The electrically operated time control mechanism 25 includes two switches indicated at 26 and 21. When the time control is set for manual control of the oven burner 2 the switches 26 and 2''! are disposed as shown in full lines in Fig. l;

but when the time control is set for automatic The time control can bewire 34, solenoid I5 and back through wire to the other side 35 of the line. This will energize the solenoid I5 and open the valve I3, and maintain the valve I3 open as long as the valve I2 is open and the switch 29 closed. Then when the valve I2 is closed to cut-off the burner 2, the solenoid I5 will be de-energized by the opening, of the switch 29. The setting and operation of the oven temperature control valve 5 is independent of the operation of the valves I2 and I3.

When it is desired to automatically control the operation of the oven burner 2 the time control mechanism 25 is set to close the switch 21 at a predetermined time, and then after a definite valve I2 manually opened. The closing of the sequently it has not been illustrated in detail herein. There are various mechanisms of this type available any one of which can be usedv herein.

In normal manual operation of the oven burner 2 it is necessary to simultaneously open the valve I3 with, the opening of the valve I2, and

to maintain the valve I3 open as long as the valve I2 is open. In order to accomplish this I provide a switch 29. which is in series with the switch 26 when it. is in the position shown in full lines in Fig. 1. I also provide an operative connection 30. between the operating handle I4 of the valve I2, and the switch 29. through which the switch 29. is closed by the opening of the valve. 12. and is opened by the closing of the valve I2; Then, with the. time control set for manual operation, when, the valve I2 is opened as shown in Fig. 2 current will flow from one side 31' of the line through wire 32, switch 26, wire 33, switch 29,

switch 23 by the opening of the valve I2 at this time will have no effect upon the solenoid I5 since the circuit to the solenoid. I5' through the switch 23 had already been broken by the switch 26 when the time control was set. Everything is now in condition to automatically control the operation of the burner. At. the set time the control 25 will close the switch 21'. Current. will then fiow from one side 3 I of the line through. wire 39, switch 27, wires 40 and 34, solenoid I5 and back through the wire 35 to the other side 36 of the line. This will energize the solenoid I5 which will open and maintain open the valve I'3' until the switch 2"! is'again opened by the time controlv 25. Fuel willbe supplied to the burner 2 from the manifold 3 through the conduit 4 and valves i2 and I3 as long as the switch 21' is maintained closed by the time control 25 provided there is no current failure in the mean.- time. In the event of a current failure during automatic operation the electrically operated time control 25 will cease operating and the switch 27 willremain closed. The solenoid I5 Will also be de-energized by the current failure, which will colse the valve ['3 and cut off the supply of fuel to the burner 2. But as soon as. the supply of current is resumed the time control will again start operating and the solenoid Ii5 will be energized and open the valve I3 since the switch 27. remained closed during the current failure.

It is this construction and arrangement that. assures the cooking of food in the oven for the prescribed time even in the event of a temporary current failure during cooking. For example, let us assume that the timecontrol has been set to ignite. the oven burner 2 at 3, oclock and to turn it of! two hours. later, which. would under. normal; operation, be 5 oclock. At 3 oclock the. time control will close the switch 27 which, ashas been described, will cause the ignition of the burner 2. Then, unless there has been a. current failure in the meantime, the time control will open. the switch 21, two hours later, at 5 o'clock, and extinguish the burner 2. But, in the case, of a temporary current; failure, for example, from 4; oclock until 4215 oclock, the oven burner 2 and the time control 25' will be inoperative, for fifteen minutes. At 4. oclock the. burner ZLhasbeen. operating for one hoiir and according to the setting of the time control should operate one hour more. This it will do after the current comes back on because the time control has been set to hold the switch 21 closed and the valve l3 open for a total time of two hours. When the current comes back on the solenoid l will be re-energized since the switch 21 is still closed, which will open the valve l3 and again supply fuel to the burner. The time control will also start operating again and will continue to operate for one hour more before opening the switchZl thereby closing the valve l3 and extinguishing the burner 2. This will make a total of two hours that the time control maintained the valve |3 open and the burner operating, one hour before the current failure and one hour after current was again available. But due to the fifteen minutes current failure the burner 2 will be turned off at 5:15 oclock instead of at 5 oclock. From the foregoing it will be apparent that the burner 2 will always be turned on for the full length of time for which the time control is set, and no more or no less, regardless of any temporary current failure during automatic operation. After each use of the oven under automatic control the valve I2 is manually closed and the time control is re-set for manual control of the oven burner by the valve l2.

In order that the oven may be used under manual control of the burner during a prolonged current failure, I provide means by which the valve l3 may be manually operated and maintained open independently of the opening of the valve l2. This means comprises a plug 4| which is screwed into a threaded aperture 42 in the bottom of the valve casing I6. The plug 4| is mounted in axial alignment with the valve disc 22 with the outer end thereof disposed in a chamber 43 which is closed by a plug cap 44. The inner end of the plug 4| has a reduced extension 45 which extends up into close proximity to the bottom of the valve disc 22 when it is seated in the valve seat 2|. In order to open and maintain the valve I3 open by the plug 4| it is only necessary to screw the plug upwardly until it y engages and lifts the valve disc 22 from its seat 2| a sufficient distance to permit the free flow of fuel through the aperture 26 from the chamber I! to the chamber l8.

- In Figs. 4 to 7 inclusive I have shown a slightly modified form of the invention. In this form of the invention I have substituted a valve 56 for the valve |2, and a valve 5| for the valve l3,

. to by which the plug may be rotated to bring either one of the bores 54 and 55 into and out of alignment with the conduit 4.

The valve 5| comprises a casing 58 having a pair of chambers 59 and 66 therein which are divided by a partition 6| having an aperture 62 therethrough. A valve seat 63 inwhich a valve disc 64 is adapted to seat is formed about the upper end of the aperture 62. The valve disc 64 is suitably secured to the lower'end of the solenoid plunger 24 of the solenoid I 5. When the solenoid I5 is energized the solenoid plunger will lift and hold the valve disc 64 away from its seat 63 and provide communication through the aperture 62 between the chambers 59 and 66 so that fuel may flow freely from the chamber 59 into the chamber 66. When the solenoid I5 is deenergized the valve disc 64 will drop by gravity onto its seat 63 and close communication between the chambers 59 and 66 and stop the flow of fuel through the conduit 4.

In order to manually open and maintain the valve 5| open, I provide a cam 65 which is secured to a rotatable shaft 66 within a chmaber 61 below the valve casing 58. The cam 65 when rotated in a clockwise direction from the position shown in Fig. 7 is adapted to engage a valve stem 68, which is secured to and extends downwardly from the valve disc 64, and raise and hold the valve disc 64 from its seat 63. The shaft 66 and cam 65 are adapted to be rotated in a clockwise direction to open the valve by an operating handle 69 which is secured to one end of the shaft 66. A spring 76 is provided to return the cam 65 and shaft 66 to their normal inoperative positions.

One end of a link 7| is pivotally connected to the free end of the operating handle 56, of the valve 50, as indicated at 12. The other end of the link H has an elongated slot 13 therein, and is slidably and pivotally connected to the free end of the operating handle 69 as indicated at 14. With this arrangement the valves 56 and 5| may be set in three diiferent positions, with respect to each other, by the operating handle 56 of the valve 59. In the off position, as shown in Fig. 4, both the valves 56 and 5! are closed so that the burner 2 cannot operate. As shown in Fig. 5, the valves 56 and 5| are set for manual operation'of the burner 2. In this position both the valves 56 and 5| are open so that fuel can flow freely from the manifold 3 through the conduit 4 to the burner 2. The movement of the operating handle 56 from the normal off position shown in Fig. 4 to the position shown in Fig. 5 brought the bore 54 of the valve plug 53 into alignment with the conduit 4, and through the link H and cam 65 raised the valve disc 64 from its seat 63. Thevalves 56 and 5| will both remain open and the burner 2 operate until the operating handle 56 is manually shifted back to the off position as shown in Fig. 4, which will close both valves 56 and 5| and cut off the supply of fuel to the burner 2.

When it is desired to automatically control the operation of the burner 2 the time control 25 is set as desired. The operating handle 56 is then shifted from the position shown in Fig. 4 tothe position shown in Fig. 6 which will bring the bore 55 into alignment with the conduit 4 and open the valve 59. Due to the elongated slot i3 in the link 16 this shifting of the operating handle 56 will have no eifect upon the valve 5| so it will remain closed. The setting of the time control 25 closed the switch 26 and started the time control operating as previously described. At the set time the time control 25 will close the switch 21 which will energize the solenoid I5 and open the valve 5|. Both the valves 56 and 5| being then open the burner 2 will start operating and will continue to operate until after a predetermined time the time control 25 opens the switch 21 which de-energizes the solenoid l5 and allows the valve 5| to close by ravity. The operation of the time control 25, either accuse under normal; operation orin the eventof a mporary current failure, is. the same; asv that. described in connection with Figs. 1 to. 3;

From the foregoing it. will be. apparent. to: thos skilled in thisv art that. Lhave. provided a. very simple and eflicien-t. mechanism for accomplishing the obj ectsof my invention.

It is. to be understood that Iv am. not. limited tothe specific construction shown and described herein as various modifications. can be. made thereto within the spirit of the invention.

Whatis claimed is:

r. In a burner control: mechanism. for a. cooking range ovenhaving. burner using gaseous fuel, the combination of a manifold, a conduit between said? manifold and. said burner through which fuel is suppliedto. said burner, a normally closed. valve in said conduit, a manually oper able valve in. said conduit, said valves. operating in conjunction with each other to. control the supply of fuel to. said burner, a. solenoid opera.- tivewhen energized to hold: said normally closed valve open, a switch, operative. connections. between said' manually operable valve and said switch by which said switch is closed by the: opening of said manually operable valve, and an electric circuit including said switch and said solenoid operative to energize said. solenoid when said switch is closed.

2. In a burner control mechanism. for a cooking range oven having a burner using gaseous fuel, the combiation of a manifold, a conduit between said manifold and. said burner through which fuel is supplied to said burner, a normally closed valve in said conduit, a manually operable valve in said conduit, said. valves operating in conjunction with each other to control the supply of fuel to said burner, a solenoid operative when energized to hold said normally closed valve open, an electric circuit including said solenoid, a. normally closed switch in said circuit, a normally open switch in said circuit, operative connectionsv between said manually operable valve and said normally open switch by which said switch is closed by the opening of said manually operable valve.

3.. Ina burner control mechanism for a cooking range oven having. a burner using gaseous fuel, the combination of a manifold, a conduit between said manifold and said burner through whichv fuel is supplied to said burner, a normally closed valve in said. conduit, a manually operable valve in said conduit, said valves operating in conjunction with each other to control the supply of fuel to said burner, a solenoid operative when energized to hold said normally closed valve open, an electric circuit including said solenoid, a switch in said circuit, time control means, operative connections between said time control means and said switch by which said switch is operated to open and close said circuit to energize and d'e-energize said solenoid at predetermined times, a second circuit including said solenoid, a normally open switch in said second circuit, and operative connections between said manually operable valve and said normally open switch by which said normally open switch is closed by the opening of said manually operable valve.

4. In a burner control mechanism for a cooking range oven having a burner using gaseous fuel, the combination of a manifold, a conduit between said manifold and said burner through which fuel issupplied' to said burner, a normally closed valve in said conduit, a manually operable valve in said conduit, said valves operating in conjunction with each. other to. controlv the supply of fuel; to said;- burnerpa solenoid operative when energized to hold said normally closed valve open, an-electrie circuit including said solenoid, anormally closed switch in: saidcircuit, a normally open switchin said circuit, time control meanscperative to. ener-e gize. and de-energize said solenoid independently of said circuit at predeterminedtimes, operative connectionsbetween said manually operable valveand said normally open switch by which said normally open switch is closed by the opening of said manually operable valve,.and operative. connec.-. tions between said time control means and. said normally closed switch bywhich said normally closed switchis opened when said time control means is set in operative condition.

5. In a burner control mechanism fora cooking range oven having a burner using gaseous fuel, the combination of a. manifold, a. conduit between said manifold and said burner through which fuel is supplied tosaid burner, anormally closed valve in said conduit, a manually operable valve. in said. conduit, said valves. operating in conjunction with each other to. control the supply of fuel to. said burner, a solenoid operative. when energized to hold said normally closed valve open, an electric circuit including said solenoid, a. normally open switch in said circuit, an electrically operated time control means, a second electric circuit which includes said time control means, a control switch by which said electric circuit and saidsec-r ond electric circuit are alternately opened and closed, operative connections between said time control means and said control switch by which said control switch is operative. to open said electric circuitand close said second circuit when said time control means. is. set in operative condition, operative connections between said .normally open switch and said manually operable valve by which said normally open switch is closed by the opening of said manually operable. valve, a third electric circuit. which includes said solenoid, a switch in said third electric circuit, and operative connections between said switch and said time control means. through which said switch is opened and closed. at predetermined times by said time control means to energize and de-energize said solenoid. 6. In a. burner control mechanism for a cooking range oven having a burner usingv gaseous fuel, the combination of a manifold, a conduit between said manifold and said burner through which fuel is supplied to said burner, a normally closed valve in said conduit, a manually operable valve having two open positions disposed in said conduit, said valves operating in conjunction with each other to control the supply of fuelto said burner, and interconnecting means between said valves by which said normally closed valve is opened when said manually operable valve is set in one open position and remains closed when said manually operable valve is set in the other open position. v 7. In a burner control mechanism for a cooking range oven having a burner using gaseous fuel. the combination of a manifold, aconduit between said manifold and said burner through which fuel is supplied to said burner, a normally closed valve in said conduit, a manually operable valve having two open positions disposed in said conduit, said valves operating in conjunction with each other to control the supply of fuel to said burner, interconnecting means between said valves by which said normally closed valve is opened when 9 said manually operable valve is set in one open position and remains closed when said manually operable valve is set in the other open position, and time control means operative to open and close said normally closed valve at predetermined times.

8. In a burner control mechanism for a cooking range oven having a burner, using gaseous fuel, the combination of a manifold, a conduit between said manifold and said burner through which fuel is supplied to said burner, a normally closed valve in said conduit, a manually operable valve having two open positions disposed in said conduit, said valves operating in conjunction with each other to control the supply of fuel to said burner, interconnecting means between said valves by which said normally closed valve is opened when said manually operable valve is set in one open position and remains closed when said manually operable valve is set in the other open position, a solenoid operative when energized to hold said normally closed valve open, and time control means operative to energize and de-energize said solenoid at predetermined times.

9. In a device of the character described the combination of a gaseous fuel burner, a conduit through which fuel is supplied to said burner, and means by which the fuel supplied to said burner through said conduit is selectively manually or automatically controlled; said means comprising a normally closed valve in said conduit, a second valve which is adapted to be manually opened and closed in said conduit, and means operative to simultaneously open said normally closed valve with the manual setting of said second valve for manual control of the fuel and to maintain said normally closed valve closed when said second valve is manually set for automatic control of the fuel.

10. In a device of the character described the combination of a gaseous fuel burner, a conduit through which fuel is supplied to said burner, and means by which the fuel supplied to said burner through said conduit is selectively manually or automatically controlled; said means comprising a normally closed valve in said conduit, a second valve which is adapted to be manually opened and closed in said conduit, means operative to simultaneously open said normally closed valve with the manual setting of said second valve for manual control of the fuel and to maintain said normally closed valve closed when said second valve is manually set for automatic control of the fuel, and time control mechanism operative to automatically open and close said normally closed valve at predetermined times after said second valve has been manually set for automatic control of the fuel.

11. In a device of the character described the combination of a gaseous fuel burner, a conduit through which fuel is supplied to said burner, and means by which the fuel supplied to said burner through said conduit is selectively manually or automatically controlled; said means comprising a normally closed valve in said conduit, a second valve which is adapted to be manually opened and closed in said conduit, means operative to simultaneously open said normally closed valve with the manual setting of said second valve for manual control of the fuel and to maintain said normally closed valve closed when said second valve is manually set for automatic control of the fuel, and a solenoid operative when energized to maintain said normally closed valve open.

12. In a device of the character described the combination of a gaseous fuel burner, a conduit through which fuel is supplied to said burner, and means by which the fuel supplied to said burner through said conduit is selectively manually or automatically controlled; said means comprising a normally closed valve in said conduit, a second valve which is adapted to be manually opened and closed in said conduit means operative to simultaneously open said normally closed valve with the manual setting of said second valve for manual control of the fuel and to maintain said normally closed valve closed when said second valve is manually set for automatic control of the fuel, a solenoid operative when energized to maintain said normally closed valve open, and time control mechanism operative to automatically energize and de-energize said solenoid at predetermined times after said second valve has been manually set for automatic control of the fuel.

CHARLES M. MAYER.

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

UNITED STATES PATENTS Number Name Date 1,174,442 Phillips Mar. 7, 1916 1,193,780 Hoag Aug. 8, 1916 1,535,240 Morris Apr. 28, 1925 2,055,384 Meacham Sept. 22, 1936 2,125,473 Vaughan Aug. 2, 1938 2,195,903 Roberts et a1 Apr. 2, 1940 2,257,024 Ray Sept. 23, 1941 2,313,890 Ray Mar. 16, 1943 2,376,212 Warren May 15, 1945 2,457,526 Brown Dec. 28, 1948