US2351973A - Oil and air control mechanism for burners - Google Patents

Description

June 20, 1944. R w OHNSON ET L 2,351,973

OIL AND AIR CONTROL MECHANISM FOR BURNERS Filed Aug. 29, 1940 4 Sheets-Sheet l INVENTORS i? v w JO/M SOAI ATTORNEY.

june 2G 1944' R2. w. JOHNSON ET AL 2,351,973

OIL AND AIR CONTROL MECHANISM FOR BURNERS Filed Aug. 29, 1940 4 Sheets-Sheet 2 "1' '"i. Q

q a u X H wp'u 1 H 46 I w 7? V INVENTORS Vim/00M .J0/M/50 TTORNEY.

June 20, 1944. w JOHNSON f 2,351,973

' OIL AND AIR CONTROL MECHANISM FOR BURNERS Filed Aug. 29, 1940 4 Sheets-Sheet 5 INVENTORS ATTORNEY F051 n! JOHMSOM R. WQJ OHNSON ET AL ,351,973

OIL AND AIR CONTROL MECHANISM FOR BURNERS Filed Aug. 29, 1940 4 Sheets-Sheet 4 m 5 s m N f 3 0 0 W w 1 0% 1 V J 5 p 6 111 W W? O; E I? HO E 8 N I filo 9 W W p 2 r W J. 5 i m r H 1 w H W 5 O mw x i w 4 4 i i I. Ill/l5 v| Zlv i 5 m w w /W w W 41 IWUWH H n H ll I, w w w Poor! msenoamr Patented June 20, 1944 01L AND AIR CONTROL MECHANISM FOR BURNERS Roy W.

Johnson and Vernon Rt Pawelsky, Milwaukee, Wia, assignors to Automatic Products Company, Milwaukee, Wis, a corporation oi Wisconsin Application August 29, 1940, Elerial No. 354,714

(Cl. 236 l) 14 Claims.

This invention relatesto an improvement in convertible control mechanism especially de= signed and adapted for use with heaters of the typewherein the heater is tired by a liquid fuel oil burner.

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

One of the objects of the invention is to provide a control mechanism of this character which may be readily converted from the type wherein the metering valve is controlled as to its position by means of a manually operable cam arrangement to one wherein the position of the valve is thermostatically controlled. In either the manually or thermostatically regulated type the means which exercise the control over the metering valve is coordinated or interlocked in its ac-= ti'on with a switch which controls the action of the electric motor-driven fan, and this in such manner that when the metering valve is adjusted to low or pilot firing position, or is fully closed, the switch is open and the fan ceases to operate, wherein in all other positions of the meterin valve the switch is closed and the fan runs'to supply the necessary quantity of air to support combustion in the combustion chamber of the burner.

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 manufacture, safe and reliable in operation, and adapted to be very readily and conveniently converted or changed over in the field from one type to the other.

In carrying out the present invention a constant level oil device is provided which has a main chamber provided with a liquid supply chamber having an outlet. A float controlled inlet valve maintains a constant level in said chamber and has combined therewith a standard type of safety shut-off means. A metering valve regulates flow through the outlet. In both forms of the invention the constant level device equipped with a manually operable control knob which is interconnected with cam means to control the position of the valve. In addition to the knob and cam means the constant level oil control is equipped in both forms with a lever mech- Air to support combustion is,

signed and adapted to regulate the operation of an electric motor-driven blower. Preferably the switch is the snap acting type and is biased to ,closed position. One type of switch which has very advantageously been employed includes a fixed and a movable contact, the movable contact being biased to interengagement with the fixed contact. A U-shaped permanent magnet straddies the fixed contact and is operativell interrelated with the movable contact, in that as the movable contact approaches or contacts the fixed contact it moves into the field of the magnet, and therefore it is engaged with or disengaged therefrom with a snap action. In both control units also a switch-operating element is provided in the control casing, which is cooperable with the movable contact of the switch to move the same to open position when the valve is moved to low or pilot fire position, or is completely closed.

In the manual type the switch-operating element is carried by an arm of a lever fulcrumed within the control casing and having another arm projecting beyond the casing and in coopera- 35 tive engagement with the manually adjustable control knob so that, as the control knob moves,

it shifts the switch-operating lever. In the thermostat type of control unit the control casing also encloses a bimetallic leaf which has one end supported on the terminal board and has its free end equipped with an extension. Between the extension and the lever mechanism of the oil control device suitable motion transmission means is provided. An electric heating element is combined with the bimetallic leaf. A room thennostat, or other suitable thermostat, controls the energlzation and deenerglzation of the electric heating element. In this instance the bimetallic leaf or its extension carries a switch-operating arm upon which the switch-operating element is mounted so that as the bimetallic leaf is flexed the switch-operating arm and its element are correspondingly moved thereby appropriately coordinating the action of the switch and valve.

after 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 perspective view showing a control mechanism embodying the present invention;

Figure 2 is a view in top plan oi the structure shown in Figure 1, with the cover plate of the control casing removed:

Figure 3 is a fragmentary view taken partially in section on line 3-3 of Figure 2, and with parts shown in elevation for the sake of illustration;

Figure 4 is a fragmentary view taken on line 4-4 of Figure .3 and looking in the direction of the arrows;

Figure 5 is a view in bottom plan of the ter minal board of the device shown in Figures 1 to 4, and of parts carried thereby;

Figure 6 is a perspective view showing a con- -trol mechanism embodying the present invention, and of the automatic or thermal responsive type, the cover plate of the control casing being removed for the sake of illustration;

Figure 7 is a view in top plan of the control unit shown in Figure 6, with the cover plate re moved for the sake of illustration;

Figures 8 and 9 are views in vertical cross section taken on lines 88 and 99, respectively 01' Figure 7, and looking in the direction of the arrows;

Figure 10 is a fragmentary view partly in side elevation and partly in longitudinal vertical cross section to illustrate the manner in which the thermal control unit is combined with the lever mechanism which controls the position of the metering valve; and

Figure 11 is a diagrammatic view illustrating the way in which the room thermostat controls the action of the electric heating element of the heat motor and the manner in which the blower motor is incorporated in the circuit and controlled by the snap-acting switch.

Referring to the drawings, and more particularly to Figures 1, 2, 3, 6, and 10, it will be seen that in both embodiments of the invention the constant level oil control device employed comprises a main casing, designated generally at H, and having a liquid supply chamber I2 therein. 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 my patents, 2,068,138, granted January 19, 1937, and 2,120,364, granted June 14, 1938.

The liquid flows out of the main supply chamber I2 through an outlet passage l3 which is connected up to the burner (not shown). A tubular valve guide H has its lower end press-fitted or otherwise suitably secured in the upper portion of the outlet passage [3, the valve guide extending vertically in the casing and terminated a short distance below the cover ii of the main casing II. The guide H is provided with a lateral opening I6 which provides for communication between the interior of the valve guide I and the liquid supply chamber I2.

A metering valve I1 is slidably fitted in the tubular valve guide I4 and meters or regulates I box-like structure of rectangular shape having a the flow from the supply chamber l2 to the bumer. A spring 28 biases the valve H to open position.

A manually, adjustable control knob i9 is mounted on the cover of the casing above the metering valve i! and acts through a cam 20 (see Figure 3) with which it is interconnected to control the position of the metering valve. The active face of the cam 20 rides on an abutment lug 20a which may be integrally formed with an adjustable supporting arm 2012 (see Figuers 3 and 10). An adjusting screw 200 controls the position of the supporting arm 20?). When the knob 19 is turned the cam 20 riding on the abutment lug 20a will raise or lower the knob 19, depending upon the direction of rotation, and also correspondingly raise and lower a valve operating stud 20d which bears on the upper end of the metering valve I! to control the position thereof. The knob I9 may be adjusted to cause the cam 20 to move the metering valve H to completely closed or shut-off position or may be ad- Justed to allow the valve ll, under the regulation of its thermostat control means to be hereinafter described, to move to full open position or to any one of several intermediate positions, as indicated by the scale or dial designated as D in Figure 6. In addition to the manually operable cam means, lever mechanism, designated generally at 22, is provided (see Figure 10), this lever mechanism having a lever arm 23 engageable with the guide pin 24 of the valve, and also having a lever arm 25 engageable with the lower headed end of a pin 26 slidably fitted in the bearing 21 provided on the top cover of the main casing. High and low fire stops, designated at 28 and 29, control the extreme positions of its lever mechanism.

The details of the construction of the metering valve, and its lever mechanism, need not be further described since per so they are not part of the present invention and are fully disclosed and claimed in United States Letters Patent 2,317,063, granted April 20, 1943, to Roy W. Johnson, for Conversion oil control.

In both embodiments of the invention a control unit, one designated generally at C and the other at C', is combined with the top of the oil control device. These control units have a number'of features of construction in common. The casings 30 thereof are the same, except that the openings therein, through which elements of the means to coordinate the action of the fan switch and the metering valve extend, have slightly different locations and are of different shapes and sizes. Each casing consists of a flat or shallow removable cover plate 3|. Three screws 32 are employed in each instance to releasably secure the control casing in position on top of the main casing.

In each control casing a terminal board or panel of insulating material, designated at 35, is

provided, the terminal board being fastened by screws 38 to short post 31 provided on the control casing. On each terminal board a snap acting switch, designated generally at S, is provided. These switches are identical. Each switch S comprises a movable contact, designated generally at 38. Its movable contact 38 is in the form of a blade spring, one end 39 of which is fixed to a binding post 40, usually connected to one side of the line. The body portion ll of the blade spring contact 38 is offset downwardly from the binding post 40 and from the under side of the terminal board 35, and at its outer end has rier 42 to which a contact button 43 is secured.

Contact button 43 is cooperable or engageable with the contact button 44 of a fixed contact 45. The fixed contact 45 is also in the form of a blade spring which has one end secured by rivets 40 to the terminal board and has its contact button carrying portion offset slightly downwardly from the under side of the terminal board. Although this contact 45 is fixed in the assembly it is adjustable, and its adjustment is controlled by means of an adjustable screw 41 threadedly interconnected with a magnet clamp 48 fastened to the top of the terminal board by the rivets 45 and a third rivet 45'. The lower end of the screw 41 bears against an intermediate portion of the contact 45, and may be-adjusted to cause it to flex downwardly more or less, the inherent resiliency of the blade spring contact 55 provided for this required fiexure.

After adjustment has been made at the factory, the screw is usually permanently secured in the proper adjustment by dropping some solder around the upper portion thereof. The movable contact 38 is biased into engagement with the fixed contact under the influence of its own inherent resiliency. In order that the switch may open and close with snap action, a U-shaped or yoke-like permanent magnet 50 is provided. This magnet is carried by the magnet clamp 40, and for this purpose a portion of the clamp 48 is offset to provide a socket-like formation 48, which is snugly fitted about the body portion and upper parts of the legs of the magnet 50. Lugs 49, struck from the clamp I8, retain the magnet in the clamp 48'. The lower portions of the legs of the magnet 50 project down through an opening 35' provided there or in the terminal board 35 and straddle the fixed contact 45. The poles of the magnet are so disposed that when the movable contact 38 approaches and is in engagement with the fixed contact, its contact button 43 and adjacent areas of its portion 42 are in the field of the magnet 50. Thus, as the movable contact 38 moves towards closed position it will be quickly drawn into engagement with the fixed contact. Likewise, when the movable contact 38 is first acted upon to cause it to move away from the fixed contact 45, energy will be stored in the blade spring contact 38, and after it has been sufficiently intensioned it will spring away from the fixed contact 45 with a snap action. The fixed contact 45 has a lateral extension i which connects up with the binding post 52 leading to one terminal of the fan motor. The other terminal of the fan motor connects to the other side of the line.

In both forms of the invention the movable contact of the switch S has a strip of insulating material, designated at 55, fixed to the under side thereof and projecting therebeyond. Rivets 55 may be utilized to secure the insulating strip 55 to the movable contact 38 and may also constitute the means which fastens the contact carrier 42 t0 the body portion 4| of the movable contact 38. The means which causes the switch to open at the proper time in each instance coacts with the projecting portion of this insulating strip 55.

In the form of the invention shown in Figures 1 to 5, inclusive, a switch-operating lever, designated generally at 60, is provided, and at one end has downturned pivot ears 0L, The ears 6! have alined openings which register with openings in the ears 62 of a mounting bracket 63, supoverlies the strip 55 is formed with an internally ported on the underside of the terminal board. A pivot pin ll extends through the alined apertures of the ears II and 52 and so provides for the fulcrum of the lever within the control casing. The lever has an integral lever arm 66 which projects out through an opening 61 provided therefor in the end wall of the control casing, and which has a laterally deflected end 58 engageable with the underside of the'fiange I! of the control knob l0. Hence, as the control knob moves down, the lever is swung downwardly. In order to cause the lever to follow the movements of the control knob when the latter moves upwardly, a spring 59 is provided which has a coil l0 mounted on the pivot pin 54 and has one angularly bent end ll abutting the edge of the bracket 63 and another and 12 pressing upwardly on the underside of the lever 60. The lever 00 is also provided witha laterally extending integral arm 13 which has its outer end overlying the outer end of the insulating strip 55. The end portion of the arm 13 which threaded, flanged bearing opening 14. A switchoperating element in the form of a screw 15 is threaded into this flanged bearing opening and has its lower end rounded and engageable with the strip 55. A spring 15 is compressed between the head of the screw 15 and the arm 13 to releasably secure the screw in any adjustment. With this construction the switch remains closed in all adjustments of the knob l9 except the lower pilot fire adjustment, or when the valve is fully closed. At such time the knob l9 moves downwardly to such extent as to cause the switch lever 60 to swing downwardly and its screw 15 to press the strip 55 downwardly and open the switch 8.

In the form of the invention shown in Figures 6 to 10, inclusive, a bimetallic leaf has one end fixed as at 80' to the underside of the terminal board, and, of course, to a portion of the terminal board spaced from the switch. An electric heating element 8|, encased in a wrapping 82 of mica or other suitable electric insulating material, is supported on the bimetallic leaf in heat-exchanging relationship therewith. Rivets 83, or the like, coact with the mica casing or wrapping of the electric heating element to secure the electric heating element in position on the leaf. An extension 85, secured to the free end thereof, extends out through an opening 86 in the control casing, and at its outer end overlies and is engageable with the upper end of the motion transmission pin 26. r

A room thermostat, or other suitable thermostat, controls the energization and deenergization of the electric heating element 8|. A switchoperating arm 90 has one end secured as by rivets 8| to the outer end of the bimetallic leaf 80. This arm projects laterally from the bimetallic leaf and the projecting portion thereof is upwardly offset and at its outer end carries a switchoperating screw 92 which is engageable with'the insulating strip 55 of the associated switch S when the leaf 80 moves the valve to low or pilot fire, or causes the switch to be opened. A spring 93 releasably secures the screw 02 in any adjustment. As shown in Figure 11 the room thermostat designated at R has the usual fixed contact I00 and movable blade contact IN. A wire l02 connects the fixed contact I00 with binding post 5 of the terminal board. Wire I03 connects binding post 5 with one terminal of the secondary I04 of a step-down transformer designated generally at T. The other terminal of the secondary I III is connected by wire It]! to one terminal of the electric heating element 8|. The other terminal of the electric heating element Bl connects by wire I06 with binding post 4 of the terminal board. Wire I 01 connects binding post 4 with the movable blade contact Illi of the room thermostat R. The primary winding I08 of the transformer T is connected by wire I09 to binding post 3. Wire H connects binding post 3 to one side of the line. The other terminal of the primary winding I08 of the transformer T connects by wire III to the binding post 0. Wire H2 connects binding post 40 to the other side of the line. One terminal of the fan motor designated at F is connected by wire H3 to binding post 3, and hence to one side of the power line. The other terminal of the fan motor F is connected by wire I to the binding post 5. With this arrangement it is obvious that room thermostat R controls the energization and de-energization of the electric heating element 8| of the heat motor, whereas the snap action switch S regulates the starting and stopping of the fan motor F. It is to be understood from the foregoing that in the embodiment of the invention shown in Figures 1 to manual operation of the knob I9 is required to turn on the fuel and the blower, whereas in the embodiment of the invention shown in Figures 6 to 9, the action of the metering valve and of the blower is controlled by the bimetallic leaf 80, which in turn is regulated in its action by the electric heating element BI and its control, room thermostat R.

From the foregoing it will be understood that the present invention provides a very advantageous coordination over the operation of the metering valve and of the blower and does this in a simple and practical fashion and in installations wherein the regulation over the metering valve is effected either entirely manually or un-- der the control of a thermostat.

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 made without departing from the spirit of the invention or the scope of the subjoined claims.

We claim:

1. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid fuel supply chamber provided with an outlet, a single metering valve for regulating fiow through said outlet, means for controlling the position of the valve, a control housing mounted on and secured to the top of the main casing, a terminal board disposed in the control housing, a switch adapted to control the operation of an electric motor-driven blower, said switch being mounted on the terminal board and including a fixed contact and a movable contact biased into engagement with the fixed contact, a switch-operating arm actuated by said means, an adjustable screw carried by the portion of the arm adjacent the movable contact of said switch, said movable contact switch having an extension of insulating material disposed to be engaged by the screw when the valve is moved to low fire position whereby then to efi'ect opening of the switch, said control housing, and all cable to and removable from the main casing as a unit, and readily releasable means for securing the control housing in position on the main housing.

2. A control mechanism of the character described'for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid fuel supply chamber provided with an outlet, a single metering valve for regulating flow through said outlet, means for controlling the position of the valve, a control housing supported on the main casing, a terminal board supported in said housing, a switch adapted to control the operation of an electric motordriven blower and having its fixed and movable contacts supported on said terminal board, binding posts carried by the terminal board and con nected to the fixed and movable contacts of the switch, a member supported on the terminal board and operatively interconnected with said means, said member moving toward and away from th terminal board as the valve is moved from closed to open position and vice versa, a switch-operating arm carried by said member and cooperatively interrelated with the movable contact of the switch so as to cause the switch to open when the valve is moved to a certain position, said control housing, and all of the elements contained therein, being applicable to and removable from the main casing as a unit, and readily releasable means for securing the control housing in position on the main housing.

3. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid fuel supply chamber provided with an outlet, 9. single metering valve for regulating flow through said outlet, means for controlling the position of said valve, 8. control housing mounted on and secured to the main casing, a terminal board of insulating material supported in the housing in spaced relation to the walls thereof, a snap action switch adapted to control the operation of an electric motordriven blower and having a fixed blade-type contact and a movable blade-type contact both mounted on the terminal board, said movable blade-type contact being biased by its inherent resiliency into engagement with the fixed contact, a U-shaped permanent magnet supported on the terminal board, straddling the fixed contact and cooperatively interrelated with the movable contact to cause the switch to open and close with a snap action, a member supported on the terminal board and shiftable toward and away therefrom, said member being interconnected with said means so as to be moved toward and away from the terminal board as the valve is moved from open to closed position and vice versa, a switch-operating arm carried by said arm and movable therewith, an extension of insulating material on the movable contact switch, an adjustable screw carried by said arm in engagement with said extension to open the switch when the valve is moved to a certain position, said control housing, and all of the elements contained therein, being applicable to and removable from the main casing as a unit, and readily releasable means for securing the control housof the elements contained therein, being appliing in position on the main housing.

4. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid fuel supply chamber pro vided with an outlet, a single metering valve for regulating now through said outlet, means for controlling the position of said valve, a control housing mounted on and secured to said main casing, a terminal board supported in said housing, a switch adapted to control the operation of the terminalboard and operatively interrelated with said contacts to provide for opening and closing of the switch with a snap action, a switchoperating arm actuated by said means and effective to move the movable contact out of engagement with the fixed contact when said means moves the. valve to a certain position, said control housing, and all of the elements contained therein, being applicable to and removable from the main casing as a unit, and readily releasable means for securing the control housing in position on the main housing.

5. A control mechanism of the character described for use in regulating the supply of oil and' air to an oil burner and comprising a casing having a liquid supply chamber provided with an outlet, a single metering valve for regulating flow through said outlet, thermostatically controlled means ccoperable with the valve to control the position thereof, a control casing mounted on the main casing, said thermostatically controlled means including a single electro-responsive power element mounted in the control casing and operatively interrelated with the valve, a snap action switch mounted in the control casing and adapted to regulate the action of an electric motor-driven blower, said switch being biased to closed position, a switch-operating element disposed in the control casing and interconnected with the electric-responsive element so as to be shifted thereby to eflfect opening of the switch when the electro-responsive element moves the valve to a certain position, said control casing, and the elements contained therein, being applicable to and removable from the main casing as a unit, and readily releasable means for securing the control casing in position on the main casing.

6. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid supply chamber provided with an outlet, a single metering valve for regulating flow through said outlet, lever mechanism for controlling the position of the valve, a control casing mounted on the main casing, a single electro-responsive power element in the control casing and operatively interconnected with the lever mechanism to control the action of the valve, a thermostat for regulating the margin-- tion and deenergization of said electro-responsive power element, a snap action switch mounted on the control casing and adapted to control the operation of an electric motor-driven blower, a switch-operating arm controlled as to its position by said electro-responsive power element and cooperable with the switch to open the same when the electric responsive power element shifts the valve to a predetermined position, said control casing, and the elements contained therein, being applicable to and removable from the main casing as a unit, and readily releasable means .for securing the control casing in position on the main casing.

scribed for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid. supply chamber provided with an outlet. a single metering valve for regulating flow through said outlet, lever mechanism interconnected with the valve for controlling the position thereof, a control casing mounted on the top of the maincasing, a single bimetallic leaf supported in said control casing an electric heating element combined with said leaf, a thermostat for regulating the supply of current to said electric heating element, motion transmission means between said leaf and said lever mechanism, a snap action switch disposed in the control casing and biased to closed position, a switch-operating arm connected to said leaf so as to be shifted thereby, anyadlustable screw carried by said lever andcooperable L with said switch to move the same to open position upon shifting of the bimetallic leaf a predetermined extent in one direction, said control casing, and the elements contained therein, being applicable to and removable from the main casing as a unit, and readily releasable means for securing the control casing in position on the main casing.

8. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid supply chamber provided with an outlet, a single metering valve for regulating flow through said outlet, lever mechanism interconnected with the valve for controlling the position thereof, a control casing mounted on the top of the main casing, a single bimetallic leaf supported in said control casing, an electric heating element combined with said leaf, a thermostat for regulating the supply of current to said electric heating element, motion transmission means between said leaf and said lever mechanism, a snap action switch disposed in the control casing and biased to closed position, mo- 1 tion transmission means between said leaf and said switch effective to open said switch when the valve is moved to a certain position, said control casing, and the elements contained therein, being applicable to and removable from the main casing as a unit, and readily releasable means for securing the control casing in position on the main casing.

9. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid fuel supply chamber, provided with an outlet, a metering valve for regulating flow through said outlet, means for controlling the position of 'the valve to raise and lower the flame in the burner, a control housing mounted on the main casing, a terminal board supported in said control casing, a switch adapted to control the operation of an electric motor-driven blower, said switch being carried by the terminal board and being biased to closed position, and a switch-operating element shiftably supported in the housing and interconnected with said means whereby the switch will be opened when the valve is moved to a position to lower the flame in the burner a predetermined extent and will be closed in other positions of the valve.

10. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid fuel supply chamber provided with an outlet, a metering valve for regulating flow through said outlet, means for controlling 7. a control mechanism of the character dethe Position of the valve. control housing mounted on and secured to the top of the main casing, a terminal board disposed in the control housing, a switch adapted to control the operation of an electric motor-driven blower, said switch being mounted on the terminal board and including a fixed contact and a movable contact biased into engagement with the fixed contact, and a switch-operating arm actuated by said means and eflective to move the movable contact out of engagement with the fixed contact when said means moves the valve to a certain position.

11. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid fuel supply chamber provided with an outlet, a metering valve for regulating flow through said outlet, cam means for controlling the position of said valve, a manually adjustable knob disposed exteriorly of the casing for adjusting said cam means, a control casing releasably secured to the main casing, a switch adapted to control the operation of an electric motor-driven blower, said switch being disposed in said control casing and biased to closed position, a lever fulcrumed within the control casing and projecting therebeyond and into operative engagement with the control knob, and a switchoperating element carried by said lever and effective to open the switch upon predetermined adjustment of said knob.

12. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner, and comprising a main casing having a liquid fuel supply chamber provided with an outlet, a metering valve for regulating flow through said outlet, cam means for controlling the position of said valve, a manually adjustable control knob mounted on the top of the casing and interconnected with the cam means for adjusting the same, a control casing mounted on the top of the main casing and releasably secured thereto, a switch adapted to control the operation of the electric motor-driven blower, said switch being mounted in said control casing and being biased to closed position, a switch-operating lever fulcrumed within the control casing, said control casing having an opening adjacent said knob, said lever having an arm projecting through said opening and operatively interrelated with said knob so as to be shifted by the knob when the latter is adjusted, and means providing for the transmission of motion from the lever to the switch to move the same automatically to open position upon a certain adjustment of said knob.

13. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner and comprising a main casing having a liquid fuel supply chamber provided with an outlet, a metering valve for regulating flow through said outlet, cam means for controlling the position of said valve, a manually adjustable control knob disposed above the top of the casing and interconnected with the cam means for adjusting the. same, a control casing mounted on the top of the main casing adjacent said knob, asnap action switch biased to closed position and adapted to control the operation of an electric motor-driven blower, said switch being mounted in the control casing, a switch-operating lever fulcrumed within the control casing, said control casing having an opening in the portion thereof disposed between the lever and the knob, said lever having an arm projecting through said opening and engaged with and shifted by the knob as the latter is adjusted, and means for transmitting motion from the lever to the switch upon predetermined adjustment of the knob so as to effect automatic opening of the switch upon certain adjustment of said lever.

14. A control mechanism of the character described for use in regulating the supply of oil and air to an oil burner, and comprising a main casing having a liquid fuel supply chamber provided with an outlet, a metering valve for regulating flow through said outlet, cam means for controlling the position of said valve, a manually adjustable control knob mounted on the top of the casing and interconnected with the cam means for adjusting the same, a control casing mounted on the top of the main casing and releasably secured thereto, a switch adapted to control the operation of the electric motor-driven blower, said switch being mounted in said control casing and being biased to closed position, a switch-operating lever fulcrumed within the control casing, said control casing having an opening adjacent said knob, said lever having an arm projecting through said opening, the outer end of the projecting portion of the arm of the lever being engageable with the lower peripheral edge of the knob, a spring maintaining the outer end of the lever arm engaged with said peripheral edge of the knob whereby the lever moves up and down with the knob, and means provided for the transmission of motion from the lever to the switch to move the same automatically to open position upon a certain adjustment of the knob.

ROY W. JOHNSON.

VERNON R. PAWELSKY.

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