US1814002A - Thermostatic oven control mechanism - Google Patents

Description

July 14,1931. I A; H. KOHLMEYER ET AL 1,814,002 v THERMOSTATIC OVEN CONTROL MECHANISM 2 Sheets-Sheet Original Fled Jan. 23, 1.928

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July 14, 1931.

A. H. KOHLMEYER ET AL.

THERMOSTATIC ov EN CONTROL MECHANI SM Original Filed Jan. 215, 1928 2 Sheets-Sheet VMM l 21H50: mtr/Q Patented July 1d, 1.931

UNITED STATES PATENT .l oFFlcEj i Arretrati: H. xonmilnm am) FREDERICK A. xonLMEYEn, on nn'rnom, MTGHTGAN THEBMSTATIC OVEN' CONTRLMECHANISM Application led January 23,1928, Serial No. 248,588. Renewed ibecember 9, 1980.

This invention relates to the ovens of gas stoves, and particularly to mechanisms for controlling in common the ventilation of such ovens and the delivery -of gas to the burners thereof.

`An object of the present invention is to exercise automatic control over an ovenventing damper and a valve inthe pipe delivering fuel to the burner of the oven by 'l0 mechanism responding toa single thermostatic means.

Another obg'ect is to provide forthe facile adjustment o the temperature at'whichit takes effect.

Still another object is to reduce a thermostatic oven control mechanism of the described character to a maximum simplicity, to thereby minimize the original cost and the expense of upkee 90 These and various other objects the invention attains by the construction hereinafter described and illustrated in the accompanying drawings, wherein:

Fi re 1 is a front view of an oven equipped with the improved control mechamsm.

Figure 2 is a vertical sectional view of the same taken upon the line 2-2 of Figure 1. Figure 3 is a horizontal sectional view of said oven taken upon the line 3-3 of Figure 2.

Figure 4 is a rear View of the oven. VFigure 5 is an axial sectional view of a valve adapted to be thermostatically controlled.

Figure 6 is a detail elevational view of the thermostatic control member.

In these views, the reference character 1 designates an loven which may or may not constitute an integral portion of a gas range.

' Preferably said oven is provided with hollowwalls filled with some suitable heat insulation such as is indicated at 2. Access is had to the oven by the usual hinged door 3 at the front thereof, said door being n ormally held closed by a suitable latch 4 as is common practice. It is preferred to dispose in the lower portion of said oven a perforated false bottom 5 between which and the true bottom of the oven, one or more burners 6 -it is preferred to slightly space a pair of such a mechanism to regulate.

' are mounted. In 'order that the heated air and .gases rising from said burners in the Vusual manner may be distributed with substantial uniformity within the oven proper,

plates 6a from the side walls of the oven and '-to perforate said plates for the discharge into the oven of the gases rising between said plates and side walls.

To the burners 6 is connected a gas de? so:

livery pipe 7 and the delivery of gas through said pipe is adapted to be controlled by the .usual manually operable valve 8.

At the rear of the oven 1 the pipe 7 has an upwardly arched portion in which is provided a valve 9 (see Figure 5)A adapted to regulate the flow of fuel responsive to only a slight effort.l As will-presently appear, this valve is under thermostatic control.

Beneath each burner 6 there is formed in the oven bottom one or more openings 10 through whichv air may be supp-lied tothe burners 6 to support combustion. Preferably baffle plates 1l are secured to the oven slightly below the openings 10 to minimize the downward radiation of heat from the burners.-

In the rear wall of the oven, and preferably in the center portion of said wall, there is formed an outlet 12 for air and gases, the so necessary circulation through the oven being thus established jointly by the openings l0 and 12. Such ventilation is regulableby a damper 13 controlling the opening 12 and hinged to the oven, preferably exteriorly thereof. v A

Describing now a mechanism. for thermostatically controlling the valve 9 and damper 13 in common, 14 designates a thermostat disposed within the oven preferably in the top portion thereof, since the maximum temperatures are encountered in said portion. While said thermostat may be of various forms, it is preferred to' form this device of a vbi-metallic sheet metal plate, utilizing differential co-eflicients of expansion of its component metals to cause it to flex proportionately to the ltemperature to' which it is exposed. One end of said thermostat is hinged upon a bracket l5 carried by the rear wall l.

of the oven and its other end is engaged by a rod 16 which passes through a front wall of the oven and carries an actuating crank 17 externally adjacent to said wall. The forward end portion of the rod 16 is threaded into a feed nut 18 rigidly secured in any suitable manner t'o the front wall'of the oven and preferably set into said wall. In order to permit a free swinging of the thermostatic plate 14 about its hinged end responsive to longitudinal adjustment of the rod 16, 1t is preferred to thread the rear end portion. of said rod and to engage its threads by a pair of nuts 19, one at each side of the plate 14, having their opposing faces spherically rounded to permit the desired play between said rod and plate. Also the opening 2Oa formed in said member to receive the rod 16 is slightly elongated to permit of the necessary flexure of said member.

The mechanism actuable by the thermostat 14 comprises a bell crank 20 exteriorly p-ivoted upon the rear wall of the oven and elongated substantially vertically. The actuating connection from the thermostat to said bell crank is established by a pin 21 freely slidable in an opening 22 in the rear oven wall, and engageable at its front end with the mid portion of the plate 14. An abutment 23 engageable by said pin is carried by a screw 24 threaded in the upper end of the lever 20 and is adjustable to and from said pin. A link 26 establishes a. swingingconnection between the lower end of the lever 20 and the damper 13, and it is preferred to provide said link with a series of longitudinally spaced openings (see Figure 2) to permit its connection to said lever at various points of its length to thereby regulate the degree of opening of the damper 13.

To control the valve 9 by the lever 20, the stem 9a of said valve carries at its forward end an abutment 27 adapted to bear against and be actuated by the lever to close said valve. The open position of the valve is normally established by a spring 28 coiled upon the stem 9a between the casing of said Valve and said abutment. A leather diaphragm 29 in said casing establishes a seal against leakage of gas.

In the operation of the described mechanism, when the temperature within the oven rises beyond a predetermined point, the resulting fiexure of the member 14 acts through the pin 21 upon the bell crank 20 to rock the upper end thereof rearwardly so that the consequent forward actuation of the lower portion of said lever tends to close the damper 13. The described actuation of the bell crank further acts through the stem 9a and abutment 27 to shift the valve 9 toward its seat. Thus the flow of gas to the burners is reduced and the oven temperature is maintained at the desired minimum.

It is to be understood that the actuation of the valve 9 will in no event be sufcient to full cut off the delivery of gas to the burner. If tlsiat were permitted, the subsequent opening of the valve by the. spring 28 would result in escaping gas.

When the construction is originally tested, the screw 23 is adjusted to assure a response of the lever 20 to deflection of the thermostat throuofh a suitable range. The user of the ovenfliowever, may more definitely regulate the thermostatic mechanism by turning the crank 18 and thus feeding the rod 16 forwardly and rearwardly to swing the thermostatic member 14 correspondingly. Preferably a suitable arcuate dial piece 30 is asso' ciated with said crank and on said dial piece is indicated by radial markings a series of temperatures which may be maintained in corresponding positions of adjustment of the crank 17.

Said mechanism is of a relatively simple nature, largely because of the use of a single thermostat to exercise both of the desired functions of fuel control and ventilation control. Because of its simplicity and the fewness of its parts, the mechanism is relatively inexpensive and is not likely to get out of order.

While it will be apparent that the illustrated embodiment of our invention herein disclosed is well calculated to adequately fulfill the objects and advantages primarily stated, it is to be understood that the invention is susceptible to variation, modification and change within the spirit and scope of the subjoined claims.

What we claim is:

1. In a thermostatic control mechanism, the combination with lan oven having openings for the admission and discharge of air, of a burner for heating said oven, means forv delivering fuel to said burner, a damper controlling one of said openings and a valve arranged exteriorly of the oven controlling said fuel delivery, a lever pivoted between its ends upon the oven exteriorly thereof, an actuating connection from said lever at one side of its pivot to said damper, an actuating connection from said lever at the other side of its pivot to said valve, a thermostat within the oven subjected to the heat thereof, and a pin slidable in a wall of the oven transmitting control from said thermostat to said lever.

2. I n a thermostatic control mechanism, the combination with an oven having a vent opening in a wall thereof, of a lever member exteriorly pivoted upon said wall, adamper controlling said opening, means for actuating said damper from one end of said lever, a thermostat within the oven subjected to the heat thereof, and a pin slidable in a wall of the oven forming an actuating connection to said lever from said thermostat.

3. In a thermostatic control mechanism, the combination with an oven and a heater for damper controlling said a device Ogni?? controlhng energization o sai heater, -a

thermostat within the oven, a lever exteriorlypivoted upon the oven,^means for actuating said lever by said thermostat, and direct actuating connections fromsaid lever to said damper and control device.

4. In a thermostatic control mechanism, the combination with an oven having an air vent opening in a wall thereof, of a closure for said opening, a burner for heatin said oven, a valve exteriorl adjacent to sai wall controlling delivery ogfuel to said burner, a lever pivoted upon said wall, a direct actuating connection to said closure from one end of said lever, a thermostat within said oven, means operating throu h said wall ada ted to actuate the other en of said Alever rom said thermostat, and means carried by said lever between its ends exercising control of said valve.

In witness whereof we hereunto set our hands.

AUGUST H. KOHLMEYER. FREDERICK A. KOHLMEYER.

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