US2343188A - Control mechanism for burners - Google Patents

Description

Feb 29, 1944- R. w. .JOHNSON ET A1.

CONTROL MECHANSM FOR BURNERS Filed July 19, 1941 3 Sheets-Sheet l INVENTO OH W fO//A/ ma uxq ATTORNEY.

Feb. 29, 1944. O R-W JOHNSON ETAL 2,343,188

CONTROL MECHANISM FOR BURNERS Filed July 19, 1941 3 Sheets-Sheet 2 INVENTORs Fav nl. JMA/50M TTORNBY Feb. 29, 1944. R W JOHNSON ET AL 2,343,188

CONTROL MECHANISM FOR BURNERS Filed July 19, 1941 3 Sheets-Sheet 3 a I 7 O 6. 40 #$7 v'mn-nun a 35 52K olli! III ATTORNEY.

Patented Feb. 29, 1944 CONTROL MECHANISM FOR'BURNERS Roy W. Johnson and William A. Biermann, Milwaukee, Wis., assgnors to Automatic Products Company, Milwaukee, Wis., a, corporation oi' Wisconsin Application July 19, 1941,' Serial No. 403,120

17 Claims.

This invention relates to an improvement in a control mechanism especially designed and adapted for use with heaters of the type wherein the heater is red by a liquidv fuel oil burner.

A typical installation is one in which a hot air furnace or heater employs a pot type burner, or its equivalent, to which oil or liquid fuel is fed by gravity under the control of a metering valve embodied in a constant level oil control device, and in which air to support combustion yis supplied to the combustion chamber of the burner byV means of an electric motor-driven fan.

One of the objects of the present invention is to provide a control mechanism of this character which automatically regulates the action of the metering valve and the electric motor-driven fan f in such fashion that the fan is not turned on until the metering valve hasbeen open suinciently to raise the fiame to an extentnecessary to require the forced draft to sustainpropercombustion,land, also, to anextent which precludes the possibility ofthe forced draft extinguishing f the flame.

Another object of the invention is to provide a control 'mechanism'of this character 'and having the advantages mentioned, which also provides for continued operation of the fan after the metering valve has been shifted to low or pilot re position, thereby `preventing the formation of carbon or soot and insuring clean, complete, and odorless combustion at all times.

A further object of the invention is to provide a control mechanism of this character, which is simple, compact, and closely organized in construction, easy and comparatively inexpensive to reliable and ment.. and combination of parts, which will bev hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming a part of this specification, and in which:

Figure 1 is a view in top plan of a control justable control knob removed and witli the cover for the control housing shown in transverse section, all for the sake of illustration;

Figure 4- is a view in'bottomplan of the terminal board of the control mechanism and of the parts carried thereby; I 4

Figure 5 is a view partly in side elevation and partly in vertical, longitudinal section, taken on line 5 5 of Figure 1, parts being omitted for the sake of simplicity in illustration;

Figure 6 is a fragmentary section view taken4 on line 6-6 of Figure 1, parts being omitted for the sake of simplicity in illustration;

Figure ,7 is a view in transverse, vertical cross section, taken -on line 1-1 of Figure 5, with parts shown in elevation for the sake of simplicity in illustration;

Figure 8 is afragmentary, sectional view similar to Figure 5 and illustrating the snap-acting switch in its closed position;

Figure 9 is a group view in perspective of parts of the snap-acting switch;

Figure 10 is a fragmentary view in vertical cross section illustrating the metering valve construction and the manually operable cam means for adjusting the same;

f Figure 1l isa diagram of the electric circuits` embodied in the control mechanism;`

Figure l2`is a view similar to Figure 3 show` ing a modified form of the invention; and

Figure 13 is a fragmentary view intop plan illustrating the keeper slot for the heat motor latching lever. c

`Referring to the drawings it will beseen that the constant level oil control device in which the present invention is embodied comprises a main casing, designated generally at Il, and having a liquidsuppiy chamber I2 therein.A Liquid fuel `is supplied to and maintained at a constant level in said chamber I2 by mechanism (not shown) but well known and widely used in this art and fully disclosed and claimed in United States Letters Patents 2,068,138, granted January 19, 1937, and 2,120,364, granted June 14, 1938.

The liquid flows out of the main chamber I1 mechanism'embodying the present inventionap-s through an outlet passage I) which is connected to the burner (not shown). A tubular valve guide I4 has its lower end press-fitted or otherwise suitably secured in the upper portion in the .outlet passage I3, the valve guide I4 extending vertically in the casing II and terminating a short distance below the cover I5 of the main casing II.` The valve guide is provided with'lat-` eral port or opening I6A which establishes communication between the interior of the valve guide I4 and the liquid supply chamber I2.

A metering valve I1 is slidably fitted inthe tubular guide I4 and meters or regulates the ow from the supply chamber-I2 to the burner.'- A spring I8 biases the metering valve I1 to open position.

A manually adjustable control knob I9 is mounted on the cover I5 of'- the main casing above the metering valve I'I and acts through a cam 20 with which it is interconnected to control `the position of the metering valve I1. The

I lactive-face of the cam 20 rides on an abutment lug 20a which may be integrally formed with an adjustable abutment supporting arm 20h. An adjusting screw 20c controls the position of the supporting arm 20h and consequently the position of the abutment lug 20a. When the knob I9 is turned, the cam 20a, riding on the abut-- ment lug 20a,fwill raise or lower the knob I9, dependingupon the direction of rotation ofthe lknob,'and Willfalso correspondingly raise yand lower a valve-operating stud 20d xed to and movable with the knob I9, and having its lower endfbearing on the upper end of the metering v4I and being secured in valve I1 so as to control the position thereof.

The knob I9 may be adjusted to cause the cam 20 to ymove the metering valve to completely closed or shutting oil position, orv it may be adjusted to allow the valve I1, under the regulation of its thermostatic control means to be hereinafter more fully described, to vmove to full open position, o r to any one of several intermediate positions, as indicated by the `scale or dial designated at D in Figure 1. y

In Aaddition to the manually operable cam means, lever mechanism, designated' generally at 22, is provided, the lever mechanism 22 havl ing a lever, arm 23 engageablewith the laterally extending guide pin 24 of the metering valve I1, and` also having a lever arm 25 engageable with the lower headed end of a pin 26 slidably-fltted .in a bearing 21 provided therefor on the cover I5 of the main casing Il. High and low fire stops, designated at 28 and 29, control the extreme position of the lever mechanism 22.

Details of the construction of the metering valve I1 and its lever mechanism 22 need not be further described since per se they are not part of the present invention and are fully disclosed and claimed in the application of Roy'W. Johnson, one of the joint inventors of this case, for "Conversion oil controldevices, filed April 4, 1940, Serial No. 327,789.

vA control unit, designated generally at C', is supported on 'and detachably ysecured to the cover I5 .of the main casing II. The control unit C includes a sheet metalcasing or housing, designated generally at 30, which may comprise a bottom plate, parallel, vertical sidewalls 32, upturned cross flange 33 extending transversely of-the rear edge oi the bottom plate 3|, and

transversely extending and spaced upright front pieces 34-integral with thefront edge of the hottom plate 3l. A removable top or cover 35 ccmpletes the enclosure afforded bythe housing 30. The cover 35 is removable, but when assembled and 'is threadedly engaged with ,.internaily4 threaded openings providedA 'i'n attaching lugs 31 fixed to the side Walls 32 of the housing 30.

.Screws 3B detachably secure the controlunit to thecover lplate I5 of the main casing II.

A horizontally disposed terminal board or panel 40 of insulating material is supported within the control housing 30 above the bottom plate-3l thereof by means of posts 4|, the terminal board 40 resting on the tops of the posts position thereon by screws 42,

'A heat motor of the relay, auxiliary heater type, designated generally at H, is supported on the under side ofthe terminal board 40. 'I'he heat motor H includes a bimetallic or thermostatic strip or leaf 45, which has combined therewith an electric heating ,element or resistance 46 engaged in a wrapping 41 of mica or other 1suitable electric insulating material.V Rivets or the like 48 coact with the mica casing or wrapping 41 of theheating element 46 vand with the bimetallic leaf 45 to secure the heating element in position on thevbimetallic leaf `in heat inter-l changing'relationship therewith. Oneend of the leaf 45 is fixed toa bracket 49 suitably secured to the under side ofthe 1panel k40. A valve-operating arm 50-is riveted as at 5I to the free end of the bimetallic leaf 45. vThis arm 50 projects through an opening provided therefor in the front of the control housing and has its outer end upwardly offset, as at 52, and overlying themotion transmission pin 26. The portion 52 of the .arm which overlies the -pin 26 is provided with arm is equipped with a washer or collar 51 to retain it assembled with the arm. l A coil spring 60 encircles the stud below `the arm 52 and has one arm bearing against the head56 of the stud 55 and itsopposite arm bearing against the under side ofthe upwardly oiset end 52A of the valveoperating arm 50. 'Thestud 55 and its spring 60 provide a yieldable or lost motion connection between the valve-operating arm A50 and the motion transmission pin 26, for a purpose which will hereinafter more clearly. appear. Av sheet metal guard 6I secured to` thefront-pieces 34 of the control housing 30 surrounds andprotects the valve-operating/arm 50, its valve-operating stud 54, and the pin 26.

A snap-acting toggle switch, designated generally at S, is connected jin controlling relation totheelectric motor E, which drives the fan or blowerF. f

The snap-acting switchS includesa fixed contact, designated generally Yat 6 5, the fixed contact 65 having a contact buttont supported by a contact carrier strip B1 which is secured to and supported on as well as in with the terminal or binding post 2 carried by the panel 40. A movablecontact button` 68 is cooperably related to the fixed contact button 66. e The movable contact button 68 of the switch S is controlled byra toggle mechanism of .special construction; As illustrated in Figures 4, 5, 8, and 9, this toggle mechanism comprises stiilly resilient toggle members T and portions of a one-piece sheet metal stamping M. The stamping M is stamped or punched out of good electrical contact T' constituted by "2,343,188 -a thin 4sheet'of spring steel or other appropriately resilient metal of good electrical conductivity, and is fashioned with side members 18 and 18' cross connected at its ends by integral endmemy bers1| and 12. The end member 1| is tapered member 12 has a centrally disposed, inwardlyr directed finger 12' integrally formed therewith, the inner end of the finger 12' being tapered and being longitudinally alined with, though slightly spaced-from, the tapered projection 1|. Intermediate portions of the side members 18 and 18 are xedly supported on, though in spaced relation to, the under side of the terminal board 48, and this may be conveniently accomplished by means of rivets 13, spacing sleeves 14, and washers 16, which also serve'to secure a stopbracket 16 in position. The rivets 13 have their upper ends headed, and in the assembly these rivets have their shanks extended through openings provided therefor in the terminal .board 48, through alined openings 16 in the body portion of the stop bracket 16, through the spacing sleeves 14, past intermediate portion of the inner k edges of the side members 18 and 18Tj of the sheet metal stamping M and then through 'the washers 15. The lower ends of the rivets'are staked or riveted over into tight" andv secure'engagement with -the washers 15 so as to clamp intermediate portions of the side members 18 and 18 of the sheet metal stamping M between the lower ends of the spacing sleeves 14 and the washers 15,

and incidentally also clamp the stop bracket 16` against the under side of the terminal board 48. The rivets 13, spacing sleeves 14, washers 15, and stop bracket 16 are constituted of metal of good electrical conductivity, and together with the sheet metalstamping M serve to electrically connect the `.movable contact button 68 with the terminal or binding post the shank of which post I passes through an opening in the terminal board 48 and has its lower end mechanically secured to and in good electrical contact with the stop bracket l16. The toggle switch S is completed by a toggle spring 11 compressed between spring cups 18 and 19, the bottoms of which are indented orsocketed to adapt them to bev interfltted with the tapered projection 1| of toggle arm or member T and the tapered ends of finger 12' of toggle arm T', respectively. It 'will be understood from the foregoing description that the toggle arm or member T is constituted of the end member 1|, its finger 12', and the portions of the side members 18 and 18' located on the left hand side of the spacing sleeves 14 and washer 15 as viewed in Figures 4 and 5.

A switch operator 80, in the form of a strip'of insulating material, has a portion securely fixed by rivets 8| to the finger 12' and end member 12 Y of the toggle arm T' of the stamping M. The

switch operator 88 projects beyond the end member 12 and its outer or free end is interposed between switch actuating elements, designated generally at 82 and 8.3, respectively. These elements 82 and 83 are adjustably supported on an angle bracket 84 connected to and movable'with the-valve operatingarx58, and in fact the brack et 84 may'btconviently made an integral part of the valve-operating arm 58 although it projects laterally therefrom and is offset upwardly with respect thereto. The switch-actuating elements 82 and'83 are of identical construction and each has a knurled knob` 8 5 at its upper end, is formed with a threaded shank portion 86, which is interthreaded with an opening provided therefor'in the bracket 84, and has an annular Bange or col lar 81 engageable with the switch operator. The arrangement is such, however, that the collar 81 of the switch-actuating element 82 is below the switch operator whereby the flange or collar 81 of the operator 83 is above the same.

When the valve is moved to closed position, the valve-operating arm 58 descends. This moves the bracket 84 downwardly, bringing the actuating element 83 into engagement with the switch operator 88,` thereby shifting the toggle arms T and T' to the position shown in Figure 5. This moves the contact 68 away from the fixed contact 66 to open-the switch.

An abutment orstop 98 limits the extent to which the contact `6|! mayvmove away from the contact 66, this abutment or stop being of insulating material and being carried by a bracket 8| which is supported on the panel 48 by the terminal 2. When the valve arm 58 moves upwardly tov allow the metering valve toopen, the switch-actuating element 82 swings the switch operator 88 to `cause the toggle arms to shift to the position shown in Figure 8, whereupon the contact `68 snaps over into engagement with the contact 66 to close the switch.

The switch- actuating elements 82 and 83, by virtue of their threaded interconnection with the bracket 84, are vertically adjustable, and they are releasably maintained in any adjustment by means of split resilient lock washers 92. By providingvtwo switch- actuating elements 82 and 83, making them vertically adjustable and combining them in the manner described with the operating element 88 of the snap-actuating switch S, it is practical and convenient to so adjust these switch-actuating elements that they will control the operation of the `burner in a, specially advantageous manner, as will be hereinafter more clearly described.

As illustrated in Figure 11, a room thermostat 95 controls the energization of the electric heating element 46 ofthe heat motor H. One terminal of the electric heating element 46 is connected by a flexible wire 96 to the binding post 0r terminal 4. A wire 91 connects the binding postor terminal 4 with the movable conductive thermostat leaf 88 of room thermostat 85. A fixed contact 98 of the room thermostat is connected by a wire |88to the binding post 5. A wiie |8| connects the binding post 5 with one terminal of the secondary winding |82 of a stepdown'transformer, designated generally at |83. The other terminal of the secondary winding |82 of the transformer |83 is connected to a connector clip |84 carried by the under side of the terminal board. `A flexible wire connects the clip |84 with the other terminal of the electric heating element 48. The primary winding |88 of the transformer |83 has one terminal con nected by a wire |81 to the binding post A wire |88 connects the binding post l to one side of the power line. The other terminal of the primary coil |86 of t-he transformer |83 is connected by a wire |89 to binding post or terminal 3. The binding post or terminal 3 is connected by a wire ||8 to the other side of the power line. A Wire connects the binding post |83 to one terminal ofi` the fan motor E. The other terminal of the motor E is connected by a wire' ||2 to the binding post 2. As described, the binding post 2 is electrically connected to the xed contact 65 ofthe snap-acting switch S, whereas the' movable contact 58 of theswitch S is electrically connected with the binding post or terminal With this construction, when the room thermostat 95 is satised, the circuit of the electric heating element 46 of the heatmotor 4H is broken,

Figure 5 so ,that the contact 69 is disengaged from f contact 66 and the fan motor` circuit is `open.

Now then, if the room thermostatV callsl for heat its leaf 98 engages the xed contact 99, thereby energizing the electric heating element 46 of the heat motor H, causingl the bimetallic element 45 to Warp upwardly.I This so swings the valve-operating` lever 50 and parts carried thereby that pressure on the pin 26-is relieved and the valve spring I8 opens'thetmetering valve so that a higher 4flame is had in the burner. The setting of the switch-actuating element-82 is such that it does not come into engagement with the switch operator 80 until after the metering valve has opened a predetermined amount, this operation being desirable to avoid possible extinguishment of a low name by the forced draft;

y However, at the selected time, the switch-actu-` ating element 82 engages under the outer end of the switch .operator 80 and. thereby shifts the toggle-switch from the position shown in Fieure 5 to the positionfshown in Figure 8; In the closed position of switch S shown in Figure 8,

the contacts 68 and 65 are engaged Consequently, the circuit'through the fan motor E-is closed and the motor starts up and operates the fan to supply air to the re pot of the burner'. When the room thermostat isf satisfied, Athe circuit through the electric heating element 45 ofv the heat motor H is broken and the bimetallic strip 45 warps downwardly; therebymoving the valve-operating arm and its stud 55 downwardly to .cause the heads 56` of the studto press down on the push pin 26 and swing the lever 22 to low pilot nre position. The arm 50 may continue to move downwardly after the lever22f`is inY low fire positionpdue to the provision of the spring 60, which affords a yieldable or lost motionconnection between the vvalve-operating arm 5D and its stud 55. The provision of this yieldable conrarirl'of the lever, designated at II'LVtermnates in a rounded end H8 which underlies the outer end portion of the bimetallic leaf 45. `The other arm I 9 ofthe bell crank lever extends up thrugh y the housing and hasan oiset upper end improf jecting through a keeper slot |2| provided inthe coverfof the control casing'. The keeper slot has# one margin formed with an integral lug |22 pro-y-` vid-ing latching shoulders |23 ands|24 cooperable,A with the offset end l20 of the bell crank ||5 to releasably securethe latching lever in idle or operative position.` Figure 12 shows the keeper ||5 in full lines in idle position, in which eventthermostatic control lis had. By shifting the leverv f over to the dotted line position shown in Figures 12 and 13, and engaging itwith the keeper shoulder |24,fthe bimetallic leaf 45 isiiexed upwardly and retained in upwardly exed position out of the range of movement of the pin 26, thereby converting the mechanism into a manually controlled device.` When this is done the switchactuating elements 82 and 83 lmay be removed or else adjusted so as not to exercise any control of the snap switch, land it, of course, may be positioned as desired. yThe bell crank lever H5 is constituted of resilient metal and its arm ||9 is so formed and assembled that under the inuence of its own inherent resiliency it is biased to lhave latching engagement with the margin of the keeper sloton which the shoulders |23 and |24 are formed. f A L While we have shown and described several constructions in which the invention may be advantageously embodied, it is to be understood that the constructions shown have been selected merely for the purpose of illustration or example, and that various changes in the size, shape, and arrangement.. of `the, parts may be madepwithout departing from the spirit of the invention or scope of the subjoined claims. A,

We claim: 1. A control mechanism of the character described for use in regulating the supply of oil and air to-an oil burner a'nd comprising a burner, a meteringk valve for regulating flow to the burner,

l, a .heat motor controlled in its action by means er including-.an electric motor-driven fan, `a

nection in the motion transmission train between Y the heat motor H and the valve makes it practical and convenient to set the switch-actuating element B3 so that it will not engage the switch operator 80 for a predetermined time after the metering valve has been shifted to low pilot re position. Consequently, the fan motor continues to supply forced draft to the burner after the metering valve has been shifted to-low pilot re positiony thereby scavenging the burner and insurng complete and odorless combustion.

lThe present invention also proposes to provide control mechanism of this character with means for throwing the heat motor H out of action so that, if desired, the control exercised over the switch controlling the startingA and stopping of said fan motor, and two, independently adjustable, switch actuators carried by and movablev with said movable motor element, one of said actuatorsfunctioning to close the switch on movement of said motor element a predetermined distancein one direction, the other of said actuators functioning to open said switch upon predeterminedmovement of said vmotor'element in an opposite direction.

v2; A control mechanism ofl the character described for use in vregulating the subplyof oil and air to an oil burner and comprising aburner, a casing having a liquid supply chamber provided with an outlet, a metering valve for regulating flow through the outlet, a biinetalllc leaf operatively interrelated with the valve to control the position thereof, an electric heating element combined with said bimetallic leaf, a thermostat regulating the supply of currenty to said electric heating element, means for supplying air'to the burner including an electric motor-driven fan, a switch controlling the starting and stoppingfof said fan motor, and two adjustable actuating elements for the the switch carried by and movable with'the bimetallic leaf, one of said elements functioning to close the switch on movement` of the leaf a predetermined distance in one direction, the other of said elements functioning to open said switch upon predetermined movement of the leaf in an opposite direction'.

3. A control mechanism of the character described for use in regulating the supply of oil and air to an oilburner and comprising a burner, a. metering valve for regulating-dow to the burner. a heat motor controlled in its action by means responsive to the temperature to be regulated, a valve operator actuated by the heat motor, motion transmission means'between said operator and said valve and including a yieldable connection providing for continuedl movement of said heat motor after the valve is arrested in its low re position, means for supplying air to the burner including an electric motor-driven fan, a switch controlling the starting and stopping of the fan motor, and means utilizing said continued movement of the heat motor for opening said switch and stopping the motor a predetermined time after the valve is moved to low re position.

4. A control mechanism of the character described for use in regulating the supply oi oil and air to an oil burner and comprising a burner, a casing having a liquid supply chamber provided with an outlet, armetering valve forl regulating flow through said outlet, lever mechanism mounted in the casing and cooperable with the valve for shifting the same from high fire to low fire pilot position, high and low fire stops for the valve, a cover for the casing having an opening therein overlying said lever mechanism, a vmotor transmission pin slidable through said opening and operatively engaged with the lever mechanism in the casing, said pin projecting beyond the casing, a control housing mounted onand secured to the cover of the casing at one side of Asaid pin, a terminal board of insulating materialsupported within the housing in spaced relation with theV Walls thereof, a bimetallic leaf supported on said terminal board, a valve-operating arm secured to the free end of said leaf and projecting upwardly therefrom into an overlying relation with the pin, a spring projected motion transmission element carried by the portion of the arm overlying' the pin and engageable with the pin, an electric heating element combined with the leaf, a thermostat for regulating the supply of current to said electric heating element, means supplying air to the4 burner including a motor-driven fan, a snap action switch controlling starting and stopping of said fan motor, means actuated by said leaf for opening said switch and stopping the motor a predetermined time after the valve is moved to low fire position.

5. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner comprising a burner, a casing having a liquid supply chamber provided with an outlet, a metering `valve for regulating flow through said outlet, high and low fire stops for the valve, a bimetallic leaf, motion transmission means between said leaf and said valve including a yieldable connection providing for continued movement of the leaf after the valveis arrested in low fire position, an electric heating element combined with said leaf, a thermostat for regulating the supply of current to Vsaid element, means for supplying air to the burner including a motor-driven fan, a snap action switch con;

scribed for use in regulating the supply of oil and* air to an oil burner and comprising a burner, a casing having a liquid supply chamber provided with an outlet, a metering valve for regulating iiow through said outlet, high and low re stops for the valve, a bimetallic leaf cooperable with the valve to control the position thereof from a high fire position to a low re position, an electric heating element combined with said leaf, a thermostat for regulating the supply of current to said electric heating element, means for supplying air to the burner including a motor-driven fan, a snap-acting switch controlling the starting and stopping of said fan motor, a switch operator combined with the switch and projecting therefrom, a bracket carried'by said leaf, and an actuating element for the switch operator adjustably supported on the bracket and cooperable with the operator to open the switch and stop the motor a predetermined time after the valve is moved to low re position.

7. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a burner, a casing having a liquid supply chamber provided with an outlet, a metering valve for regulating flow through said outlet, high and low nre stops ,for the valve, a bimetallic leaf cooperable with the valve to control the position thereof from a high re positionto a low fire position, an electric heating element combined with said leaf, a thermostat for regulating the supply of current to said electric heating element, means for supplying air to the burner including a motor-driven fan, a snap-acting switch controlling the starting and stopping of said fan motor, a switch operator combined with the switch and projecting therefrom, a bracket carried by said leaf, and two independently adjustable actuators for the switch carried by said bracket, one of said actuators functioning to close the switch on movement of said bracket a predetermined distance in one direction, the other of said actuators opening the switch upon predetermined movement of the bracketin an opposite direction.

8. A control mechanism for use in regulating the supply of oil and air to an oil burner and comprising a burner, a metering valve for regulating flow of oil to the burner, a heat motor having a bimetallic leaf interconnected with the valve for controlling the position thereof, means for supplying air to the burner including an electric motor-driven fan. a switch controlling the starting and stopping of said electric fan motor, an operator for said switch adjacent said leaf, a bracket carried by the leaf and overlying said operator, and two switch actuators adjustably supported on said bracket, one of said actuators engaging the operator from above and the other engaging the same from below whereby one of said actuators functions to close the switch upon predetermined movement of the leaf in one direction and the other functions to open the switch upon predetermined movement of the leaf in the opposite direction.

9. A control mechanism for use in regulating the supply of oil and air to an oil burner and comprising a burner, a metering valve for regu- 10. A control mechanism for use in regulatingl the` supply of oil andair toan oil burner and comprising a burner, a metering valve for regulating flow of oil to the burner, a heat motor havi ing a'bimetallic leaf interconnected with the valve for controlling the position thereof, means for supplying air tothe burner including-an electric motor-driven fan, a switch controlling the starting and stopping of said electric fan motor, an operator'for said switch adjacent said leaf, a bracket carried by the leaf and ,overlying said operaton'and two switch actuating screws threadedly interconnected with said bracket, one of said screws having a collar engageable with said operator from above, the other having a collar engageable with said operator from below. d

11. A control mechanism for use in regulating the supply of oil and air `to an oil burner and comprising a burner, a metering valve for regulating fiow of oil to the burner, high and low fire stops for the valve, a heat motor having a bimetallic leaf, motion transmission means between said lleaf and said valve including a yieldable connection providing for continued movement of said leaf after the valve is arrested in low ire position, meansfo'r-'supplying air to the burner including an electric motor-driveny fan, a switch controlling the starting and stopping of said electric fan motor, and a switch actuator adjustably supported on the leaf actuator and utilizing the continued movement ofthe leaf after the valve is arrested in low fire position to vautomatically open the switch and stop the motor after the lapse of a predetermined interval of time.

12. A control mechanism for use in regulating the supply of oil and air to an oil burner and comprising a burner,y a metering valve for regulating iiow of oil to the burner, high and low fire stops for the valve, a heat motor having a bimetallic leaf, motion transmission means between said leafand said valvev including a yieldable connection providing for continued movement of said leaf after the valve is arrested in low iire position, means for supplying air to the burner including an electric motor-driven fan, a switch controlling the starting and stopping of said electric fan motor, an operator for the switch adjacent said leaf, and two switch actuators adjustably supported on said bracket, oneof said actuators engaging the operator from above and utilizing the continued movement of the leaf after the pilot valveis arrested in its low fire position to automatically open theeswitch andV stop the motor after the lapse of the predetermined Ainterval of time, the other of said actuators engaging the operator from below and functioning to automatically close the switch and start vthe motor after the valve opens to a predetermined 2,343,188 1 nung new of on to the bumeea heat motor havf stops for the valve, a heat motorfhavlng a bi- `metallicleaf interconnected with the valve to control the` position thereof, means for'supplying air to the burner including an electric motor-v 6 driven fan, a double throwsnap action switchV controlling the starting andstopping of said electric fan motor, an operator for said switch adjacent saidv leaf, and means carried by the leaf and cooperable with said operator to effect clos- 10 ing of the switch upon predetermined movement of the leaf in one direction and opening of the switch upon predetermined movement of the leaf in an opposite direction.

14. A control mechanism for use in regulating the supply of .oil and air to an oil burner and supply chamber `provided with an outlet, a metering valve for regulating flow through said outlet, lever mechanism mounted in the casing and '20 cooperable with the valve for shifting "the same from high re to low fire position, high and low fire stops for the valve,'a cover for the casing having an opening therein overlying said lever mechanism, a motion transmission pin slidable beyond said opening and operatively engagedA with the lever mechanism in the casing, said pin projecting beyond the casing, a control housing mounted on and secured to the cover of the cas-- ing at one side of said pin, a terminal board of insulating material supported within the housing in spaced relation with the walls thereof, a heat motor includinga. bi-metallic leaf supported on the terminal board, a valve-operating arm secured to the free end of -said leaf and projecting outwardly of the housing and .finto the overlying relation with the pin, a spring projected motion transmission element carried by the portion of the 'arm overlying the pin and engageable with the pin, means supplying'air 40 tothe burner including anelectric motor-driven fan, a doubleV throw snap acting switch controlling starting and stopping of said fanmotor, an operator for the switch adjacent the leaf, a bracket carried by theleaf and overlying the operator, l and two Aswitch actuatingk screws threadedly interconnected with said bracket, one of said screws having a collar engageable with said operator from above, the other having a collar engageable withsaid operator from below.

15. A control mechanism for use in regulating the Asupply of oil and air to an oil burner, and comprising a burner, a main casingy having a liquid supply chamber provided with an Voutlet, a metering valve for regulating flow through said outlet, high and low fire stops for the valve, acontrol housing mounted on the main casing, a terminal board of insulating material supported within said housing infspaced relation to the walls thereof, a heat'motor lncludinga bimetallic leaf supported .on said terminal board, motion transmission means between the free end of the leaf .and said valve, means for supplying air to the burner including an electric motor-driven fan, a double throw` snap action switch mounted on the terminal board adjacent said bimetallic leaf and connected in circuit to sa-idfan motor to control the starting and stopping thereof, an operator for said switch adiacent the leaf, and means carried by and movable with the leaf and cooperable with the operator to effect opening and closing of the switch at predetermined times.

comprising a burner, a casing having a liquid 16. A control mechanism for use in regulating the supply of oil and air to an oil burner,

and comprising a burner, a main casing having a liquid supply chamber provided with an outlet, a metering valve for regulating flow through said outlet, high and low fire stops for the valve, a control housing mounted on the main, casing, a terminal board of insulating material supported within said housing in. spaced relation to the` walls thereof, a heat motor including a. blmetallic leaf Supported on said terminal board, motion transmission means between the free end of the leaf and said valve, means for supplying air to the burner including an electric motor-driven fan, a double throw snap action switch mounted on the terminal board advjacent said bimetallic leaf and connected in cirply chamber provided with an outlet, a metering valve for regulating flow through said outlet, manually adjustable cam means for controlling the position of the valve from 'fully closed position through intermediate nre position 4to high fire position, lever mechanism also interconnected with the valve for controlling the posi` tion thereof within the range permitted by the 5 manually adjustable cam means, high and low tire stops cooperable with said lever mechanism, a control housing mounted on the main casing, a heat motor controlled in its action by means responsive to the temperature to be regulated and l0 including a bimetallic leaf supported in the control housing, motion transmission means freely coupled to the leaf but actuated thereby to control the 'position of the valve, a latching lever fulcrumed within the control housing and having an arm engageable with the bimetallic leaf, and

an arm projecting exteriorly of the control housing, the control housing having a slot through which the projecting end of said last named arm extends, said slot having latching shoulders cooperable with the adjacent portion of the projecting arm of the lever to releasably secure thelever in'idle position with its rst named arm out of engagement with the bimetallic leaf or in latching position with its ilrst named arm engaged with and warping the leaf out of operative nterengagement with said motion transmission means whereby the control mechanism is subject solely to the control of said manually adjustable cam means.

ROY W. JOHNSON. WIILIAM A. BIERMANN.

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