US1943582A - Oven control - Google Patents

Description

A. P. CHESTER ET Al.

ovEN CONTROL Filed Feb. 15. 1932 2 Sheets-Sheet l gil . ATTORNEYS.

3 i6, 1934o A, P, CHESTER ET M 1,943,582

lOVEN CONTROL n Filed Feb l5, 1952 2 Sheets-Sheet 2 T-f1 q 4# 5 4 7 'z -P' QZ 34': o 45 @0 5:/ 45 l 5? 54 :Mb 84. 75 e o -IELH qb 50 f 37 E 15 l 7s 10 44 4l 4Z 74 64 /Z 4o '/z 7/ ai 7- 7J ATTORNEY XWW m4@ Patented Jan. 16, 1934 OVEN CONTROL Alden P. Chester and Dewey H. Hill, Kokomo, Ind., assignors to Globe American Corporation, Kokomo, Ind., a corporation Application February 15, 1932. Serial No. 592,979

`6Claims.

This invention relates to an oven control mechanism and particularly to the type of oven control which is adapted to stop the supply of heat and to stop the air circulation of an oven at the end of a predetermined heat supply period so that the oven functions thereafter as a iireless cooker. The principal object of the present invention is to improve the mechanism disclosed and claimed in our prior application, Serial No. 573,748, filed November 9, 1931.

One feature of the present invention resides in the provision of means for manually tripping the damper closing and 4fuel shutoff mechanism, said means being conveniently located for operation by the user.

Another feature of the invention resides in the use of separate valves for controlling the rateof :dow of the fuel and for the fuel shutoff. By this means, the adjustment of the rate of fuel supply 20 is undisturbed Whenthe fuel supply is shut oi and the same rate of supply may be used in the next cooking operation without readjustment of the regulating valve, or, if desired, the valves may be so arranged that when the shutoff valve is automatically closed, the rate control valve is automatically opened to full open position. In the latter case, the rate control valve is leftin the best position for starting the oven burner. The full open position of the rate control valve is also the position at which approximately 90% of the cooking is done so that when the valve is left in this position it is in readiness for the most probable next use of the oven.

Other features of the invention reside in the particular arrangement of parts described and illustrated in the following specification and the attached drawings:

L Figure 1 is a plan view of an oven having control mechanism mounted on the top. Figure 2 is a vertical sectional view through the oven and control mechanism. Figure 3 is an elevationalCA View of a fragment of the front plate of the stove upon whichthere are mounted the elements used by the operator to set the control mechanism.

45 Figure 4 is an enlarged sectional view taken on the line 4 4 of Figure 1. Figure 5 is a sectional view taken on the line 5-5 of Figure 4. Fig. 6

is a sectional view taken on line 6-6 of Fig. 4.

Figure 7 is a sectional view taken on the line 7-7 of Figure 4.

An oven is shown in the drawings formed with an nuter shell 10 and an inner shell 11 having suitable insulation material 12 therebetween and tted with an oven door 13. In the lower part 55 of the oven chamber there is located a burner `mits the movement of the said stem toclose 14 supplied with fuel through a pipe 15 leading from a valve 16. The valve 16 receives the fuel from a valve 17 which in turn is supplied by a pipe 18 leading from a pressure regulator 19. Fuel is supplied to the regulator 19 from 60 any suitable fuel supply source through a pipe 20. The valve 16 is formed with a valve seat 21 with which a valve stem 22 cooperates to control the rate of fuel supply to the burner. A stem 23 is fastened to the valve stem 22 and 05 projects outside of the valve, as best seen in Figure 5. A diaphragm 24 is fastened between the stems 22 and 23 and serves to prevent the escape of gas from the valve. A cam 25 engages the end of the stem 23 and is mounted upon a shaft 26 supported by bearings 27 on the housing of valve 16 and by a bearing 28 on the front plate 29 of the stove. The shaft 26 carriesY at its outer end an arm 91 connected by a link 92 to a lever 93 rotatably mounted upon a tubular member 53. The lower end of the lever 93 carries a pin 93 projecting through an arcuate opening in the front plate 29. The pin 9a serves as a handle for adjusting the valve 16 and registers with a scale marked upon the front 80 plate 29 and indicated in Figure 3 by the legend Low-Med-High. By this means, the movement of the pin 94 in a clockwise direction, referring to Figure 3, serves to rock the shaft 26 and cam 25 for moving the valve stem 22 to re- 85M duce the flow of gas through the valve seat 21. When the pin 94 is moved in the opposite direction, the pressure of the gas upon the stem 22 moves the same to permit a greater ow.

` The valve 17 is provided with a valve seat 90 30 having a valve member 31 cooperating Atherey with. The member 31 is universally mounted upon a stem 32 in turn fastened to a stem 33 projecting outside the valve and engaging a cam 34. A diaphragm 35 is fastened between the 95 stems 32 and 33 and serves to prevent leakage of gas from the valve. A spring 36 abuts at one end against the diaphragm 35 and at the opposite end against a partition 37 within the valve and serves to draw the member 31 against the valve seat 30 to shut olf the supply of gas. The cam 34 is so formed that when it is rotated to one position, it moves the stem 33 to open the valve 17 and when in another position, perthe valve.l The valve 17 is also tted withla small pipe 38 through which gas is taken to supply a pilot light for an oven burner in any suitable manner. Since this pipe enters the valve ahead of the valve seat 30, it is constantly supplied with fuel whether the valve isI open orclosed.

, rlhe apparatus for automatic control 'of the oven vent and the fuel cutoff valve 17 is principally supported upon a pair of castings 39 and 40 carried upon the shell of the oven, as best seen inligure 4. The casting 40 has formed therein a horizontal partition 41 having an opening 42 therethrough. The opening 42 is closed by amovable closure 43. When the closure 43 is raised, the products of combustion from the oven pass through the opening 42 and out through a vent opening 44 to any suitable chimney or similar disposal device. When the clo sure is lowered, no circulation of gases from the oven is possible and the oven, therefore, operates as a '.reless cooker.

Upon the top of the casting 39 there are mounted a bearing bracket 45 and a bearing bracket 46. rI'he bearing bracket 45 has clamped therein a bushing 47 and a tubular member 48 is rotatably supported in said bushing and in the bracket 46. The cam 34 is mounted upon one end of said tubular member and the said member also carries a toothed cam 49 and a cam 50. The opposite end of the tubular member 48 carries a iitting 51 which mates with a tting 52 to form a joint permitting a certain amount of universal motion. The iitting 52 is mounted upon one end of a tubular member 53, the opposite end of which carries a knob 54 rotatably supported upon the front plate 29 of the stove. A collar 55 is carried upon the tubular member 48 and serves as an abutment for one end of a torsion spring 56, the opposite end of which abuts against a lug 57 formed upon the bushing 47. rihe spring 56 tends to rotate the tubular members 48 and 53 in the counterclockwise direction, referring to Figures 3, 5, 6 and 7. This movement is limited when a pin 58 on the toothed cam 49 strikes a stud 59 mounted upon the casting 39. v

The closure 43 has fastened thereto a stem 60 passing'upwardly through the casting 39 and fastened at its upper end to a yoke 61 which straddles the tubular member 48 and carries-a roller 62 at its upper end. The roller 62 engages the periphery of the cam 50 and the said periphery is so shaped that when the tubular member 48 is rocked in a clockwise direction, the yoke 61 is elevated to raise the closure 43 and permit the escape of the products of combustion from the oven. When the tubular member 48 has been moved inthe counterclockwise direction by the spring 56 until the pin 58 strikes the stud 59, the cam 56 assumes the position shown in Figure 7 and the closure 43 drops by its own weight to close the opening 42.

' A pair of bolts 63 are fastened at their upper ends to the casting 39 and extend downwardly through suitable openings in the casting 49. A cross member 64 is supported upon the lower end oi the said bolts and in turn supports a small box 65. A rod 66 of invar or other material having a low coemcient of expansion is threadedly engaged in one oi the walls of the box and extends through the opposite wall and across the top of the oven chamber. A tube 67 ofl brass or other material having a higher expansion coeicient surrounds the said rod and abuts at its other end against an adjustable bushing 68 threadedly mounted upon the end of the rod 66 and locked in position by a lock nut 69. The inner end oi the tubey 67 abuts against a bushing 70 in turn abutting against one arm 7l of a Ythe rod 80 and engaging the washer 85.

bell crank lever pivotally mounted within the box 65. The opposite arm 72 of the bell crank lever rests upon avwasher 73 carried upon the lower end of a vertical stem 74 projecting upwardly to a point immediately beneath the cam 49. The upper end of the stem carries a serrated block 75 and the teeth of said block engage the periphery of the toothed cam 49, as best shown in Figure 6. A compression spring 76 abuts against the lower surface of said block and against a depressed portion 77 of the casting 39 and thus serves normally to force the block 75 upwardly against the cam 49. It will be noticed that the radial dimension of the cam 49 varies in such manner that as the said cam is moved in the clockwise direction the block 75 and the stem 74 are forced downwardly. The greater the movement of the cam 49 in the clockwise direction, the lower will be the position assumed b'y the stem 74. it will also be seen that when the teeth of the cam 49 engage the teeth of the block 75, the said block serves as a latch'to restrain the cam and the tubular member 48 against rotation in the counterclockwise direction.

In the operation of this apparatus, as the oven is heated, the tube 67 expands a greater distance than the rod 66 due to the diierence in their coeiicients of expansion. The bushing 70 is, therefore, pressed against the lever arm 71 and the lever arm 72 operates to press the stem 74 downwardly. The movement of the stem 74 disengages the teeth of the block 75 from the cam 49 andthusjpermits the spring 56 to rotate the'tubular member 48 to close the draft closure 43 and to close the valve 17. The initial position of the rod 74 determines the degree of temperature which must be attained in the oven before the expansive force of the tube 67 operates to trip the same. Thus if the cam 49 is rotated to push the stem 74 downwardly to its maximum distance, the tube 67 must expand through a greater distance before the lever arm 72 is operated to trip the stem 74 than would be the case if the rod 74 had been moved downwardly through only a portion of its travel. The inner end of the i knob 54 carries a dial 78 which is visible through an opening 79 in the front plate 29 and which carries a graduated scale, the graduations of which indicate the degree of temperature which must be reached for each setting of the cam 49 before the stem 74 will be tripped.

A rod 80 extends longitudinally through the tubular members 48 and 53I and carries at its outer end a button 8l set into a suitable recess in the knob 54. A compression spring 82 sur- ,i

rounds a portionv of the said rod and abuts against a washer 83 held in place upon the rod by Ia pin 84. The opposite end of the spring 82 abuts against a washer 85 clamped between the fittings 51 and 52. The said spring, therefore, tends to force the rod 80 to the left in Figure 4 and this movement is limited by a pin 86 passing through The inner end of the rod 80 extends beyond the tube 48 and engages the upper end of a bell crank lever 7 87 pivotally mounted on a bracket 88 carried upon the top of the casting 39. The opposite arm 89 of the said bell crank lever engages the legs of a forked lever 90 which is also pivotally mounted upon the bracket 88. The opposite end of the lever 90 rests upon the top of the block 75. By this means, the operatormay push the button 81 at any time and thus move the levers 87 and 90 to depress the stem 74 and trip thedevice irrespective of the temperature attained in the oven.

THS

ln the operation of the apparatus, the pressure regulating valve 19 furnishes fuel to the valve 16 under a denite pressure. Therefore, for a given setting of the valve 16, the oven will reach a predetermined temperature at a predetermined time, as more thoroughly discussed in the before mentioned prior application. The predetermined temperature and hence the predetermined time of cooking are determined by the setting of the cam 49. For example, if it has been determined that a certain food will be thoroughly cooked if the oven is brought to 500 degrees Fahrenheit temperature with a medium flame, the knob 54 is rotated in a clockwise direction until the indication 500 on the dial 78 is visible, thus setting the stem 74 to the point at which it will be tripped when a' 509 degree temperature is reached in the oven. The pin 94 is moved to the fR/led mark to adjust the valve 16 for medium name.v At the end of the time required for the medium ame to bring the oven to 500 degrees temperature, the stem Z4 is tripped, the spring 56 rotates the tube d8, and the draft closure 43 and valve 17 are closed. The oventhereafter operates as a flreless cooker to complete the cooking.

of the food.

if it is desired. that the rate control valve 16 be moved to full open position ready for the next cooking operation when the fuel and vent shuto mechanism is tripped, a pin 96 is fastened to the dial 78 in such position that it engages the lever 93 in the movement of the dial. The said lever is moved thereby into the High position. If this feature is not desired, the pin 96 is omitted and the adjustment of valve 16 is left undisturbed when the shutoff mechanism is tripped.

Y The foregoing specification describes a preferred form of the invention. However,l changes from the detailsthereof may be made without departing from the scope of the invention as defined by the appended claims. For example, the thermostatic-mechanism shown in our before mentioned prior application orv any other suitable thermostatic device may be used instead of that shown herein. i

The vinvention claimed is:

l. In an oven control, the combination of an oven chamber having a vent opening adjacent the rear thereof, `a closure for said vent opening, a burner for heating said oven, a fuel supply pipe leading to said burner, a pair` of valves in said.

fuel supply pipe located adjacent said vent closure7 a rockably mounted shaft extending from a position adjacent said vent opening and said valve to a position adjacent the front of the oven, connections between said shaft and said vent closure and between said shaft and one of said valves for opening said closure and said valve when said shaft is in one position and for closing the same when said shaft is in another position. thermo.

statically operated mechanism for moving said shaft to close said closure and said valve when a predetermined temperature is reached in the oven, a second shaft extending from a position adjacent said valves to a position adjacent the frontV of the oven, connections between said last mentioned shaft and the other'of said valves for regulating the opening of said last mentioned valve, a lever rockably mounted upon the first of said shafts adjacent the forward end thereof, and `a connection between said lever and said last mentioned shaft for moving the same when said lever is moved.

2. In an oven control, the. combination of an oven chamber having4 a vent opening leading members between said shaft and said closure by u means of which'said closure is open when said shaft is in one position and ,is closed when said shaft is in another position, an operating knob upon said tubular shaft for turning the same .to open said closure, spring means for turning said shaft to close said closure, a latch for maintaine ing said shaft with said closure in open position, thermostatically operated means for'tripping said latch when a predetermined temperature has been reached in the oven, a rod extending through said tubular shaft to a position adjacent said operating knob, and a connection between the opposite end of said rod and said latch for tripping said latch when the end of said rod adjacent said op= erating knob is pressed.

3. In an oven control, the combination of an. oven chamber having a vent opening leading therefrom, a closure for said vent opening, a rock-1 ably mounted tubular shaft, connecting members between said shaft and said closure by means of which said closure is opened when said shaft is in one position and is closed when said shaft is in another position, an operating knobupon Said tubular shaft for turning the same to open said closure, spring means for turning said shaft to close said closure, a latch for maintaining said shaft with said closure in open position, thermo= statically operated means for tripping said latch when a predetermined temperature has been reached in the oven, a rod extending through said tubularshaft, a button carried by one end of said rod and positioned within a recess in said operating knob, and a connection between the opposite end of said rod and said latch for tripping said *latch when said button is pressed.

t. 1n an oven control, the combination of an oven chamber, a burner for heating said chamber, a fuel supply pipe leading to said burner, a valve in said fuel supply pipe, a rockably mounted tubular shaft, connecting members between said shaft and said valve by means of which said valve is closed when said shaft is in one position and is opened when said shaft is in another position, an operating knob upon said tubular shaft for turning the same to open said valve, spring means for turning said shaft to close said valve, a latch for maintaining said shaft with said valve in open position, thermostatically operated means for tripping said latch when a predetermined temper ature has been reached in the oven, a rod extend.-I ing through said tubular shaft to a. position adja cent said operating knob, and a connection between the opposite end of said rod and said latch for tripping said latch when the -end of the rod adjacent said operating knob is pressed.

5. In an oven control, the combination of an oven chamber, a burner for heating said chamber, a fuel supply pipe leading to said burner, a valve in said fuel supply pipe, a rockably mounted tubular shaft, connecting members between said shaft and said kvalve by means vof which said valve is closed when said shaft is in one position and is open when said shaft is in another position, an operating knob upon said tubular shaft for turning the same to open said Valve, spring means for turning said shaft to close said valve, a latch for maintaining said shaft with said valve in open position, thermostatically operated means for tripping said latch when a predetermined temper-a ature has beertreached in the oven, a rod extend-u ing through said ,tubular shaft, a button carried by one end of said rod and positioned within a to regulate the rate of fuel supply to the burner, and thermostatically operated mechanism connected to said Valves and said closures and operating when a predetermined oven temperature is reached to close said vent opening, to move said last mentioned valve to substantially full open position and to close the other of said valves.

ALDEN P. v CHESTER. DEWEY H. HILL.

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