US2372436A

US2372436A - Controlling means

Info

Publication number: US2372436A
Application number: US418427A
Authority: US
Inventors: Walter S Landon
Original assignee: Detroit Lubricator Co
Current assignee: Detroit Lubricator Co
Priority date: 1941-11-08
Filing date: 1941-11-08
Publication date: 1945-03-27
Anticipated expiration: 1962-03-27

Description

March 7 19450 W 5 LANDQN 2 3?2,436

CONTROLLING MEANS Filed. Nov. 8, 13941 4 Sheets-Sheet l A; ATTORNEY March 27, 1945; w. s. LANDQN CONTROLLING MEANS Filed Nov. 8, 3.941 4 She'ets-Sheea 2 INVENTOR M frTTORNEY 7 March 2?, 1945 W. s. LANDQN CONTROLLING MEANS 4- Sheets-Sheet Filed NW. 8, 1941 v INVENTOR amnion ATTORN EY Patented 27, 1945 UNITED STATES PATENT OFFICE 2,372,436 CONTROLLING MEANS Walter S. Landon,

trolt Lnbrlcator 'poration of Michigan Application November 8, 1941, Serial No. 418,427

13 Claims.

This invention relates generally to controlling means and is, among other uses, adapted to control the operation of a fuel burner.

One object of this invention is to provide means for automatically controlling the flow of fuel to a fuel burner.

Another object is to provide means for automatically controlling the supply of air to the burner in accordance with fuel flow.

Another object is to provide an automatic control unit which can be readily applied to a manual fuel control apparatus to render the manual apparatus automatically operable.

Another object is to provide a control device which is particularly adapted for cooperation with the fuel control apparatus.

Another object is to provide means for operation of the fuel control apparatus and the control device by the automatic control unit.'

Another object is to provide a control apparatus comprising a unitary structure composed of a plurality of readily assemblable units.

Another object is to provide means to facilitate the operation of the manual means by an automatic means.

These and other objects will be apparent from a reading of the following specification.

The invention consists in the improved construction of and combination of parts, to be more fully described hereinafter and the novelty of which will be particularly .pointed out and distinctly claimed.

In the accompanying drawings to be taken as a part of this specification, there is fully and clearly illustrated a preferred embodiment of my invention, in which drawings- Figure 1 is a view partially in side elevation and partially in vertical section on the line l-l of Fig. 2 showing a controlling means embodying the invention;

Fig. 2 is a top plan view of the controlling means with the cover member of the automatic controlling unit removed and having the casing of the control device in section on the line 2-2 of Fig. 1;

Fig. 3 is a view of one of the automatic units taken substantallyalong the line and looking in the direction of the arrows;

parts in horizontal section; r

Fig. 5 is a bottom plan view of the control device;

Fig. 6 is an enlarged view of the control device having its casing in vertical section and hav- 33 of Fig. 2

Detroit, Mich, aesignor to De- Company, Detroit, Mich, a coring certain parts broken away and in vertical section for clarity;

Fig. 7 is an exploded view of certain of the parts of the control device shown in Fig. 6;

Fig. 8 is a diagrammatic view showing the controlling means of Fig. 1 in side elevation and operatively connected to a fuel burner:

Fig. 9 is a detail view in side elevation of the terminal block for the control device as seen in Fig. 8,

Fig. 10 is a schematic view of the controlling means and wiring diagram of the application of the controlling means to a fuel burning apparatus, and

Fig. 11 is a detail lI-ii of Fig.8.

Referring to the drawings by characters of reference, the numeral i designates the casing of a constant level chamber having an inlet (not shown) which may be controlled by a float operated valve and having in its bottom wall 2 an outlet 3 preferably screw-threaded for connection to a, liquid supply line leading to a gravity fed type burner preferably of the pot type. The liquid supply line is connected to a screw-threaded inlet 3' of a strainer chamber 3 which is positioned against the lower external surface of the wall 2 and communicates with the float valve controlled casing inlet (not shown) for supplying liquid to the constant level chamber. Extending upwardly within the casing from its bottom wall 2 there is a valve housing or casing I having a vertically extending vent duct 5 communicating with the outlet 3 and terminating at its upper end above the liquid level in the chamber. The valve casing 4 has an outlet passageway 6 leading to the outlet 3 and having its inlet end provided with a valve seat member I provided with an outlet port.8 having a surrounding annular valve seat 9. The valve casing 4 has a tubular sleeve member Ill extending'upward around and laterally spaced from the seat member I and terminating above the liquid level view in section on the line within the chamber. Within the sleeve member 7 to regulate or meter flow from the chamber. A

helical coil spring I 5 surrounds the valve member II and the seat member 1 and acts upward against a collar or flange It on the valve membar ii to urge the valve member ll toward open position. The collar is is rotatably supported in an a ular groove II in the valve operating rod or s em l8 and has a finger I9 fitting and guided within a vertical slot 26 through the wall of the sleeve member ID to hold the collar l6 against rotation upon rotation of the stem i8. The slot 26 provides an inlet to the valve casing and port 8 for flow from the constant level chamber.

overlying the housing 4 and spaced thereabove, there is a bridge or supporting member 2| which extends across the chamber and is supported at either end upon spaced stepped bosses or posts (not shown) projecting inward from the side walls of casing l. Overlying and spaced above the bridge member 2i there is a cover member 21 which closes the top of and provides a top wall for the casing I and which may be secured in position by screws 28 and 28a (Fig. 2) threaded into bosses (not shown) integral with the walls of the casing l. The bridge member 2| has an upstanding tubular guide member 29 concentric with an aperture through the bridge member and aligning with the port 8. The stem l8 extends upward through the bridge member aperture and the guide member 29 in which it is rotatably and reciprocally guided. Through the cover member 21 there is an aperture 30 aligned with the guide member and port 8 and through which extends the upper end of stem l8 and the sleeve like portion of a hand grip member 3i which is secured to the stem by a screw 32 so that the stem I8 is positively rotatable by the hand grip member.

Positioned at diametrically opposite points relative to the valve member H and spaced circumferentially and laterally thereof, there are supporting bosses 33 (one of which is shown) which are rigid with the casing 4. The upper ends of the bosses 33 are longitudinally screw-threaded to receive upwardly extending screw-threaded rods or

posts

35, 36. The post 35 extends upward through aligned apertures 81, 3B in the bridge member 2i and cover member 21 respectively, the aperture 38 providing guide means for the upper end of post 35 which is provided with a kerf or screw driver receiving and adjusting slot (Fig. 2). The post 36 extends upward through apertures 39 and 40 in the bridge member 2! and cover member 21 respectively, the aperture 40 providing a guide means for the upper end of post 36 which is provided with a kerf or screw driver receiving and adjusting slot.

The cam means for operating the valve member comprises a follower member 42 cooperable with cam track members 43, 44 carried by or on the

posts

35, 36. The follower member 42 may be a short cylindrical rod projecting radially from the valve stem between the valve housing 4 and bridge member 21. The track members 43, 44 are of resilient sheet material preferably annealed sheet steel. The track member 43 has a curved track portion 45 of helical form with a low point or portion 46 and a high point or portion 41 at its opposite ends. Projecting from the track member 43 adjacent the low portion 45 there is a positioning and supporting ear 46 which is bent upward to lie in a horizontal plane above its adjacent track portion and having a circular aperture therethrough receiving and fitting the post 35. Extending upward from the high cam track portion 41 and opposite the ear 48 there is a positioning and supporting ear 56 bent to lie in a horizontal plane above the high point 41 and in a plane parallel to the plane of the ear 48. The

ear 56 has an elongated aperture therethrough to receive the post 36 and provide for adjustment, the aperture in ear 56 being diametrically opposite the aperture in ear 48. The jointure of the ears 48 and 50 with their respective cam track portions is preferably of small cross-section so that upon adjustment of the ears, as will be described hereinafter, the jointures will provide a flexible connection between the cars 48 and 56 and their respective cam track portions. The track member portion 45 which is formed as a portion of an annulus is concentric with the valve member I l and therefore partially surrounds the same. Project-- ing upward from the ear 56 at its side opposite 52 which extends through the bridge member aperture 39 and is parallel to and spaced laterally from the post 36.

The track member 44 has a track portion which is of generally arcuate form in plan view and terminates at its ends in positioning and supporting ears 53, 54 respectively, the ear 53 having a cylindrical aperture to receive and fit the post 35 and the ear 54 having an elongated aperture to receive the post 36 and provide for adjustment, the

ear 53 overlying the-ear 48. Intermediate its ends the track member 44 has a downward stepped or offset portion providing steps 51, 58, the riser portion of the upper step 51 substantially abutting the low end of track member 53 and cooperating with the low point 45 to form a stop shoulder at the low end of the track portion as. The downward facing horizontal portion of step 53 cooperates with the follower member 62 to lock or hold the conical valve portion l2 tightly against its seat 9. The arcuate or curved end portions of the track member 44 provide sufficient flexibility so that the step 58 can move upward to receive the follower member 42 and thereby resiliently press the valve to its seat. The riser portion 59 of the step 58 serves as an abutment or stop for engagement by the follower member 62 to limit final rotary movement of the valve member II when it has been seated in full closed position.

Secured on the

posts

35, 36 there are abutment members or. collars 6G, 6i respectively, providing downward facing shoulders and having stop fingers (not shown). These abutment members are of similar construction and therefore the description of one will sumce for both. The member 6i comprises a sleeve member 6d which fits the post 36 and against which the track member 63 abuts upwardly. The member be is held in its position on the post by a flanged member from which the stop finger (not shown) extends for engagement with the stop arm 5'2. With the stop finger of the member 6| positioned in engagement with the rear edge of stop arm 52, the member 6| is moved up or down on post 36 until, with the follower member 42 at the track high point 41, the valve member II will have its maximum desired open or flow position. The flanged member 65 is then permanently secured to the post 36 as by solder or the like. The track high point ear 50 is held up against the sleeve member 64 by a coil spring 61 surrounding the post 36 and bearing at its lower end upon the ear 54 of track member 44 so that the ear 54 is urged downward against or toward the valve casing 4 and the step 58 is urged toward the valve closed position. Rotation of post 36 so that the stop finger of the flanged member 65 moves away from arm 52, by clockwise rotation facing Fig. 2, will movethe abutment member 6| downward thereby lowering the high point 41 of the cam track portion 45. This or abutnient member is slid up or down on post 35 until, with the stop finger of member ll against its stop (not shown) and with the follower member 42- on the cam low point 44 and against step 51. the cam low point 40 is positioned to obtain the largest minimum or maximum pilot flow desired through slot I4. The abutment member 60 is then soldered or otherwise securely fastened to the post and thereafter upon rotation of post 35 in a clockwise direction facing Fig. 2the cam low point 48 will be lowered thereby decreasing the rate of minimum or pilot flow through the valve. The clockwise adjustment of post 35 and the lowest flow rate obtainable by this adjustment is limited by engagement with a stop (not shown) of the finger carried by the flange member of collar 60. The cam track members 43, 44 are held up against abutment member 00 by a coil spring 60 which surrounds post 35 and seats on the upper end of boss 33. The springs 51 and 50 are under compression and exert sumcient force to hold the ends of the track members 43, 44 normally in rigid fixed position. Upon rotation of post 35 to adjust the cam low point 48, the track member 43 will be flexed adjacent the jointure of the ear 50 with the track portion 41 so that the cam high point 41 will remain in its fixed position. Upon rotary adjustment of post 38, the track member 43 will flex adjacent the jointure of the ear 48 with the track portion 46 so, that the position of the cam low point 46 will remain fixed as the high point is varied or moved. The underside or follower engagement face of track. portion 45 may be provided with equally spaced radial serrations or notches (not shown). These serrations are preferably only deep enough to hold the follower member against shifting from its set position which might result from vibration or touching of the-grip member 3|.

In order to limit the opening movement of the valve member II and prevent rotational movement of the follower member 42 beyond the high point 41, a stop member (not shown) extends downward from the bridge 2| adjacent its aperture through member 20 through which stem I8 extends. This stop member extends downward sufficiently so that the follower member cannot by downward reciprocation compression of the spring I5 be thereafter ro tated in further counter-clockwise movement.

I A second valve member 69 having a hand grip member 10 similar in all respects to the valve member II and hand grip member 3| may be provided in the apparatus for providing dual outlets from the casing I. To simplify this specification and because the two valve members II and 59 I are substantially identical, the parts of the valve member 69 will be referred to by the same numerals with the exponent a added unless otherwise noted and the details of valve II only will be shown. It will be noted however that it is discretionary as to whether the second valve member is to be provided or not and depends upon the burner to be'controlled.

The operation of the valve as so far described is as follows: With the constant level chamber connected to a suitable source of oil supply and the outlet 3 connected to the burner or the like, the low point 46 is adjusted within the minimum limit range by rotation of post 35 to provide proper flow through slot I4 for pilot fire and the cam high point 41 is adjusted by rotation of post 36 within its range of maximum adjustment to of the valve stem upon the lower end wall of aarasae 3 permits ofan adjustment from themaximum safe detemiine the maximum flow rate through slots 7 flow rate to a lesser maximum rate. The collar I3 to the burner. Either the minimum or the altering the other position. The valve member I I, when rotated to closed position as above noted. is urged to its seat by the resilience of track member 44 and the hold the valve member tightly seated. As the valve member II is rotated by the hand grip 3| in a counter-clockwise direction or toward open position any dirt on the seat will be sheared by rotation of the spring loaded valve. When follower member 42 passes from under the track portion 58 which leads it to the cam low point 46, the valve member II will have a quick opening movement as the follower member rises to engage the cam low point. There will now be pilot flow at the minimum desired rate through the pilot slot I4. As the follower member 42 leaves the track member 44, the track member 44 may have some downward movement but this will not disturb the setting of the cam low point which is at all times held in set position by spring 68 and the opposing abutment member 60. The valve member II is now freely movable toward further open position under the force of spring I5 as the follower member 42 is moved counter-clockwise along the underface of track portion 45, the serrations therein not being of sufficient depth to impede the continuous rotation of the valve member II.

ment member 6 I, then the follower member 42 will be on the cam high point 41 and substantially in engagement with the stop member.

The valve operation however may be transformed into automatic operation by the addition of a valve actuating mechanism casing I and posltioned against the cover member 21. The actuating mechanism I00 comprises a hollow casing I02 conforming in contour with the casing I and having an open top wall I03 and an open bottom wall. The casing I02 in horizontal cross section is generally U-shaped with an end wall I04 having extending side walls I 05, I06 projecting therefrom and flaring outwardly. The walls I05, I06

at their end portions are joined by a connecting end wall I01. The top wall I03 is closed by a cover I03 secured thereto as by thumb screws I01 threaded into apertured bosses IIl1 integral with the walls I05 and I06. The casing I02 has apertured projecting bosses I08, I09 extending from and in the plane of its lower end. wall and which are positioned respectively at the intersection of the walls I05, I06 with the wall I01. The bosses I00 and I09 receive the screws 28 which act to secure the casing I02 to the chamber I. The wall I01 has a forwardly projecting abutment I09 which is adapted to seat against the top surface of the cover member 21 to prevent cooking of the casing I02. The wall I01 adjacent casing I02 has a plurality of inwardly extending lugs III, 2 and II3 which extend from the wall I01 toward the opposite end wall I04 and which have aligned V-shaped slots for receiving a rod or fulcrum member I I4 which extends between the walls I05 and I06 spaced from and substantially parallel to the cover member 21. Each of the lugs III, H2 and H3 have threaded apertures therethrough in which are screw-threaded upwardly extending screws I III, IIS and 1 respectively, and which screws have head portions adapted to engage the fulcrum member II4 to rigidly hold the fulcrum member II4 within the aligned V-shaped apertures. A bell-crank lever member H8 is preferably fabricated from a piece of substantially T-shaped sheet metal by bending one of the arms or oppo sitely extending portions H9 at right angles to the plane of the metal and then bending the end portion I20 of this oppositely extending portion into a plane substantially parallel to the plane I of the sheet metal so that it extends in the same direction as the other 01 the oppositely extending portions. The other of the oppositely extending portions or arms forms one leg I2I of the bell crank lever member IIB. The portion I20 and leg I2I have aligned apertures for receiving the rod member II4 so that the member II8 may be rotated thereabout. The horizontal stem or standard portion of the T-shaped piece forms the other leg I22 of the bell crank member H and extends through an aperture in the wall I01 and has an abuttingportion I22 abutting an upwardly facing shoulder I22 of the grip member SL The bell crank member H3 is positioned between the lugs I II and H2 and has an extending conical portion I23 projecting from the leg I2I in a direction opposite to the direction of the leg I22. The conical portion I23 is positioned intermediate the upper or free end portion of the leg I2I and the fulcrum member I I4. A second bellcrank lever member I24 is constructed similarly to the lever member II8 except that it is a mirrored or reflected representation thereof. The member I24 is fulcrumed on the fulcrum memher IIII intermediate the lugs II 2 and H3 and comprises a first leg I25, a second leg I26 which extends through an aperture in the wall I 01 and an extending conical portion I 28.- The second leg I26 has an abutting portion I26 which overlies an upwardly facing shoulder I21 of the grip member 10. The legs I2I and I25 have adjacent their free ends aligned apertures for loosely receiving a horizontally extending cross bar or connecting rod I28. Extending from the sidewalls I05 and I05 and spaced slightly above the cover member I21, are a pair of inwardly extending lugs I29 and I30 respectively. The lugs I29 and I30 have screw-threaded apertures extending therethrough which face the conical portions I 23 and I20 re spectively. Screw-threaded within these apertures are a pair of adjusting pin members I3I and I 32 respectively, having conical end portions facing the conical portions I23, I20 respectively. Apertures I32 extend through the side walls I05 and I06 adjacent the outer ends of the members I3I and I32 opposite their conical end portions so that the pin members I3I and I32 may be screw-threaded within the lugs I29 and I30 from externally of the casing I02. After adjustment, the screws or pin members I3I and I32 may be held in position by set screws I3I and I32". Spring abutment members I34, I35 are positioned respectively against the conical portion I23 and conical end portion of the member I3I and a helical coil compression spring I36 is held under compression therebetween. To prevent buckling of the spring I36, the abutment'member I35 is provided with an extending guide finger or pin which is received within and is reciprocal within a guide aperture of the abutment member I34. In like manner, an abutment member I33 is p0- sitioned against the pin member I32 and an abutment member I40 is positioned against the conical portion I28 for engagement by the ends of a helical coil spring I which is held under compression therebetween. The abutment members I30 and I40 have respectively a guide aperture I42 and a cooperating extending portion I43, which prevent buckling or the spring I and are identical to the cooperating element of the members I34 and I35.

The position of the conical portions I23 and I28 are so chosen relative to the position of the pin members I3I and I32 and to the fulcrum member II4 that when the bell-crank members II3 and I24 are rotated to their extreme clockwise positions (see Fig. l) the conical portions provide seating surfaces for a plate-like supporting member I41 which ha a contour substantially conforming to that of the casing I02 and which is preferably of an insulating material such as Bakelite. The plate-like supporting member I41 is held against the upper end surface of the bosses I44, I45 and I45 by means of screws I44, I45 and I46 which extend through ap;rtures in the plate-like member I41 and are screwthreadedly received within apertures opening upwardly through the upper and surfaces of the bosses I44, I45 and I46. A bimetallic actuating element I08 is carried by and on the lower surface of the plate-like supporting member I41 substantially midway between the walls I05 and I05 and adjacent the wall I01. The bimetallic actuating element I48 i fixed to a substantially U-shaped supporting member I49 having one of its leg I50 secured as by screws I5I to the supporting member I41 and having its base portion held as by a screw I5I to the wall I01. The sensitive portion of the bimetallic actuating element I48 comprises, a bimetallic strip member having one end portion bent into a substantially cylndrical portion I53. The other end portion extends from the portion I53 as a radially extending lip portion I56. The end portion of the cylindrical portion I53 spaced from th lip portion I54 is secured to the other arm I55 of the the bottom wall of the casing I02 and engages an enlarged diameter porton I55 of the connecting rod I28 substantially midway between the bell-crank lever members H8 and I24. The portion I55 has a central circumferental recessed'portion I51 which receives an embossed or raised projecting portion I58 of the lip portion I54. An electrical resistance heater I59 is positioned within the cylindrical portion I53 and has lead wires I60, I8I extending therefrom and connected to a terminal rivet I62 and to a post I53 respectively, carried by and extending through the plate-like supporting member I41.

A transformer unit I54 of conventional design has at its upper end portion outturned flanges I55, I06, which seat against the lower surface of the plate-like member I41 and are held thereto as by screw I61 so that the unit is within the casing I02. Th secondary coil lead wires I88, I58 of the transformer I84 are connected respectively to a binding binding posts I" and I18 have wire attaching screws III, I12 respectively, on the top or outer face of the supporting means I41 and which are adapted to receive the lead wires I12 I728 from a room thermostat I18 for controlling the circuit to the heater I 58 of the bimetallic actuating element I48. The primary coil of the transformer I84 i connected by means of lead wires "4, I15 of an electrical cord I18 to a conventional male plug Ill. The end of the cord I18 is rigidly held adjacent the transformer I64 by means or a clamp I18 which ha an outstanding projecting portion I19 received within a slot (not shown) in the flange I85. The lower portion of the clamp H8 is held by means of a bolt and nut I8I to the transformer I84 and which bolt and nut I8I acts to hold the transformer core together. To additionally hold the cord H6 in place, an L-shaped member I8I ha its longer leg positioned against the upper surface of the member I41 and held thereto by one of the screws I81. The shorter leg of the member I8I extends downward and has an aperture therethrough through which the cord I18 extend and in which it has a snug lit.

The flanges I85 and I88 have screw-threaded apertures extending therethrough aligning with rectangular apertures I85 I88 in the supporting member I41 and overlying substantially horizonally projecting portions I82 and I83 of the lever members H8 and I24 respectively. Low fire adjusting screws I84 and I85 are screw-threaded respectively within the screw-threaded apertures in the flanges I85 and I88 respectively, and have upper end portions extending through the plate-like supporting member I47. The upper end portions have screwdriver slots or kerfs for reception of a screwdriver or other suitable tool for rotating the low flre adjustment -screws I84 and I85. Nuts I84 and I85 are screwthreaded onto the screws I84 and I85 respectively so that they are positioned within the rectangular apertures I85 and I88 and held thereby against rotation with the screws I84 and I85.

the nuts I84 and I 85' and the flanges I 65 and I85 are held under compression thereby so that the screws I84 and I85 are Irictionally held againstrotation relative to the flanges I85 and I88. The lower end portions of the adjusting screws I84 and I85 are engaged by the extending portions I82, I88 respectively upon predetermined counter-clockwise movement of the lever members H8 and I24 (see Fig. 1) to limit valve closing movement 01' the valve members II and 88 respectively, by the lever members H8 and I24. The adjusting screws I84 and I85 are respectively -journa1ed adjacent their lower end portions within apertures in outwardly extending flange portions of L-shaped members I82 and I88 held to the transformer core as by a bolt and nut I 82" which also holds the core together.

It will be noted that as the bell-crank lever member II8 rotates clockwise, the conical portion I23 moves nearly into alignment with the fulcrum member H4 and the conical end ortion 01' the pin member I8I so that the spring I88 while exerting an increasing total force will exert a decreasing component or force opposing this clockwise rotation. The spring I85 is so post I'll carried by the supporting member I41 and to the rivet I82. The

' bimetallic cylindrical portion I53 5 chosen relative to the angle at which it acts on the lever member I18 and to the spring I5 that v the decrease in its moment of Iorce opposing clockwise rotation is somewhat more than the decrease in moment of force exerted by the spring I5 due to its scale per inch. This construction provides in eflect a negative "scale per inch for the spring I5. Furthermore the magnitude of the moment of force exerted by the spring I38 i always less than the moment of force of the spring I5. The positioning 0! the conical portion I28 and the magnitude and scale per inch of the springs MI and I5 are so seiected that the bell-crank lever member I24 is actuated in a like manner as described relative to the bell-crank member II8. It therefore roilows that were these the only forces acting on the bell-crank lever members H8 and I24, the

valve members II and 58 would always remain in an'open position limited only by the engagement r the follower member 42 with the track member 43. The bimetal element I48, however, acts to exert its force against the enlarged diameter portion I55 or the connecting rod I28 and provides the necessary force to overbalance the sum of the moments of force exerted by the springs l5 and I5 respectively, on the lever members I24 in excess or the opposing moments of force exerted by the springs I48 and HI. ment I48 increases in temperature due to heating by the heater I58, the force exerted by the lip portion I54 urging the lever member H8 and ml in a. counter-clockwise direction, decreases moment exerted by the springs exceeds the total counterclockwise moments of force. When this occurs, the lever members H8 and I24 are rotated gradually in a clockwise direction by the springs I5 and I5. As stated hereinbefore, upon clockwise rotation of the lever members H8 and I24 the counter-clockwise moment of force exerted by the spring I38 and HI decreases at a greater rate than the decrease of clockwise moment of force exerted by the springs I5 and I5 due to their scale per inch. This not increase in clockwise moment of force on the lever members III and I24'is substantially compensated for by the scale per inch of the resiliency .oi the element I48 as it is moved by the connecting rod I28. The result is that upon initial movement or the lever member II8 and I24 in a clockwise direction upon heating of the element I48, the valve members II and 58 will move gradually toward open position but will not move throughout their entire range of allowed movement until the element I48 is heated gradually to a higher temperature. It may now be understood that with the construction and operation hereinbefore described, the valve members II and 89 will be urged by the springs I5 and I 38, and I 5 and HI respectively toward open position with a prothe valve memof the. eleis flexed by the additional net moment of clockwise force exerted by the springs I5, I5 I88 and I.

After deenergization 0f the element I48, the

commences to cool. Upon cooling to a predetermined temperature, less than the temperature of the element I48 at the time the valve members II and 88 As the elescale per inch of the element I48 is sufficient to overcome the net clockwise moment of force exerted on the lever members H8 and I24 by the be one-half of that or the travel when a dual valve instrument is used.

springs I5, I I36 and HI so that the valve members II and 69 are moved toward closed position. This movement toward closed position will be ata greater rate than the rate of the change in the free position of the element I48 upon cooling of the portion I53 due tothe decrease in clockwise moment of force caused by the eflective negative "scale per inch of the springs I5 and I5 as hereinbefore described in connection with the opening movement. In other words, the

counter-clockwise moment of force which must The valve members II and 69, however, will not be moved toward closed position with a snap movement or without continued cooling of the element I40 because the efiective negative scale per inch" of the springs I5 and I5 is not of suffi cient magnitude to completely compensate for the "scale per inch of the element I38.

It may now be readily understood that the cooperation of elements hereinbefore set forth provide a means for operating a valve or other reciprocal member by apower element exerting a relatively small force in respect to the resistance to movement exerted by the valve or reciprocal member. These elements also provide an actuator which permits a greater degree of movement of the reciprocal member than the movement afiorded by the normal movement of the actuator even when changes in movement due to levers are considered.

Should the valve member 69 be omitted and the mechanism I00 used to control a valve mechanism with only a single valve II, then the moment of force exerted on the lever member I24 in a clockwise direction will be nil and the member I24 will remain in a fixed position with the extending portion I83 in engagement with the low fire adjusting screw I85. Due to the loose connection between the connecting rod I28 and the leg I25, the rod I28? acts as a lever member fulcruined at the point of connection with the leg I25 so that the net clockwise moment of force exerted by the lever member H8 on the rod I28 acts to pivot the rod I28 about the leg I25. The force exerted by the lever member I I8 is substantially one-half of the total force exerted on the lip portion I54 when both lever members H8 and I24 are actuating valves. Therefore as the bimetallic element lip portion I54 engages the rod I28 substantially midway between the lever members 8 and I24. the force exerted on the lip portion I54 will be the same whether one or both of the lever member H8 and I24 are operating or not, the only difference being that in case the mechanism I00 is on a single valve instrument the travel of the lip portion I54 will The switch mechanism IN is attached as an independent unit to the top wall of the casing I at the end thereof opposite to the mechanism I00. The switch mechanism IOI comprises generally a rectangular casing I99 having side walls 200 and 20I, end

walls

202 and 203, a closed up- .per end wall 204 and an open lower end. The lower end of the casing I99 has

flanged portions

205, 205 extending perpendicular from the side walls 200 and 20I which seat against the cover member 21 and have contours substantially conforming to the contour of the casing I. The screw 28 extends through the flange portion 205 and securely clamps the mechanism IM to the casing I. A substantially rectangular switch unit 208 is positioned within the casing I99 and has adjacent one end :portion an aperture extending therethrough. A rod or fulcrum memher 201 having reduced end portions is carried within and fits this switch unit aperture and extends beyond each face of the unit 208, see Fig. 11. A pair of lever members 209, 2I0 have apertures 209 adjacent one end portion through which the fulcrum member 201 extends and in which the member 201 fits. The lever member 209 is positioned intermediate the switch unit 208 and the side wall 2M and the-lever member 2I0 is positioned intermediate the switch unit 208 and the side wall 200. The

lever members

209 and 2 I0 have respectively extending portions 2 and 2I2 which extend through apertures 2I3, 2 I4 respectively, in the end wall 202 and engage the upwardly facing shoulders I22 and I21 of the grip members 3I and I0 respectively.

The rectangular switch unit 208 has an operating push button .2I5 which is operable upon downward movement into the switch unit 208 to actuate the switch and establish a circuit between the lead wires 2I8, 2II connected thereto. A U-shaped member 2I0 fits over the rectangular switch unit 208 and has at its open end portion extending portions 2I9 which extend along the side walls of the switch unit 208 and have aligned apertures 2I9 for receiving and fitting on the fulcrum member 201. The open ends of the U- shaped member 2I8 have apertures 2H) aligned with an aperture 220 extending through 'the switch unit 203. A pin member 22I extends through the aperture 220 and through the aligned apertures 2I9 in the U-shaped member 2; so that the U-shaped member 2I8 is held against movement relative to the switch unit 208. The base portion of the U-shaped member 2I8 has a plate-like extending finger 222 which overlies and extends substantially parallel to the top wall of the switch unit 208, the free end portion thereof overlying the push button 2I5. A pair of

bellcrank lever members

223 and 224 are fulcrumed on the member 201, the bell-crank lever member 223 being intermediate the lever member 209 and the side wall 20I and the bell-crank lever member 224 being intermediate the lever member 2I0 and the side wall 200. The bell-

crank lever members

223 and 224 have their

upstanding arms

223 and 224 projecting above the top wall of the switch unit 208 and beyond the top surface of the finger 222. The upward extending arms 223' and 224 of the

lever members

223 and 224 are preferably joined by a bridge member 225 so that the-movement of the

lever members

223 and 224 will be in unison. The bridge member 225 overlies the push button 2I5. Preferably finger 222 has an aperture overlying the push button member 226 having is positioned an abutment a flat lower surface engageable with the top surface of the push button 2" and a recessed portion in its upper surface. The bridge member 225 has a threaded aperture therethrough in which is screw-threaded a stub screw 221 having a screwdriver slot in its upper end portion and a recess in its lower edge portion. A helical vcoil compression spring 228 is held under compression between a spring abutment member 229 and a second spring abutment member 230. The abutment members 228 and 280 have extending rod-like portions which terminate in conical surfaces for engagement with the recessed portions of the screw 221 and member 226 respectively. I'he'horizontally extend- 2Ii8' and in which in: arms of the bell-

crank lever members

223 and 224 have rectangular apertures 23I through which the pin member 22I extends and cooperates to limit rotational movement of the

lever members

223 and 224 relative to the switch unit 208. The lever members 206 and 2I0 also have apertures 232 therethrough through which the pin member 22I extends and through which stub abutment pins 233 carried by the horizontal arms of the bell-crank

members

223 and 224 also extend. The apertures 232 have shoulder portions 232 for engagement with the pin 233 so that upon predetermined counterclockwise movement of the lever member 209, the shoulder portion 232 will engage the pin 233 and rotate the

lever members

223 and 224. Engagement of the walls of the apertures 23I and 232 with the pin member 22I merely actas a limiting means to prevent movement of the respective lever members beyond the desired degree. The apertures 23I act to limit counter-clockwise rotation of the

lever members

223 and 224 so that the point of engagement of the abutment member 229 with the screw 221 does not pass beyond the line of center of the point of engagement of the abutment member 230 with the member 226 and the fulcrum member 201.

The scale per inch of the spring 228 is so chosen relative to the angle at which it acts that upon counter-clockwise movement of the bellcrank lever members 223 of force exerted in a counter-clockwise movement of the lever members '223 and 224 is substantially the same at the end of its movement as at the beginning of its movement so that the force required to move the lever members throughout their range of movement will be as nearly constant as possible.

Upon upward movement of the valve members II and 69 the shoulder portions 232 will engage the abutment pin 233 and continued counterclockwise rotation of the

lever members

209 and 2| 0, due to continued upward movement of the valve members II and 59, will rotate the

lever members

223 and 224 counter-clockwise. This counter-clockwise rotation of the

lever members

223 and 224 will move the point of engagement of the member 229 and screw 221 more nearly into alignment with the line of centers through the fulcrum member 201 and the point of enagement of the

members

226 and 230 with a consequent shortening of the spring 228. The spring 228 will therefore exert a greater component of force downward on the push button or pin 2I'5 due in part to the change in angle at which the spring 228 acts and in part to its scale per inch." This increase in downward force component is sufficient to push the pin 2I5 downward to actuate the switch unit 208. Should one of and 224, the component direction opposing the,

torotate the lever members 223 of the valve members II thewalve members II or 88 be adjusted to open further than the other of the valve members, the valve member opening the further will continue and 224 and the abutment pin 233 which cooperates with one of the lever members 208 or 2I0 resting on the valve member which moves the lesser amount, willrise from its shoulder portion 232 -into the aperture 232. A lost-motion connection is therefore had between the

lever members

223, 224 and lever members 209 and 2I0.

The extending portions 2I3 have downwardly extending ears 233' having aligned apertures for receiving a fulcrum pin 233 The pin 233 is held at either end within apertures in the walls- 200 and 20I and extends substantially normal thereto. A spring 234 has a coiled portion 238 coiled about-the fulcrum pin 233? and has one extending portion 234 abutting lower surface of the switch unit 208 and the other end portion 234* abutting the lower surface portion of the end wall 203. The spring 234 acts to urge the switch unit 208 in a counter-clockwise direction about the fulcrum member 233 and into abutting engagement with the lower end surface of an ad- Justable thrust member 236 which is screwthreadedly received within an aperture through the upper end wall 204 of the switch mechanism IM and which serves as an adjustment to be hereinafter described. To prevent accidental rotation of the thrust member 238, a lock nut 231 may be threaded onto the member 236 external of the top wall of the mechanism I00 and beneath a manual hand grip portion 238 of the thrust member 238 for abutting the wall 204.

The switch unit 208 may be positioned by means of the thrust member 236 so that the switch unit 208 may be actuated at any desired position of the valve members II and 69. If the threads on the member 236 are right hand, clockwise rotation of the member 236 (Fig. 6) will rotate the unit 208 in a clockwise direction about the fulcrum pin 233 to cause the lever member 209 and/or 2") to actuate the unit 208 at a position and/or 69 corresponding to a smaller fluid flow. Counter-clockwise rotation of the member 236 produces the opposite result.

Secured to the wall 20I, as byscrews 238, there is an electrical terminal block 240 (Fig. 9) having a male connection 24I for reception of the female end 242 of an electrical extension cord leading from a source of electrical energy such as the usual volt household supply. The block 240 also has a first female connection 243 which is adapted to receive a male conection 244 of a fan motor unit 245 which supplies forced air to the burner supplied by the outlet 3. If desired the switch 208 control a circulating means for the medium heat ed by the fuel burner. A second female connection 246 of the block 240 is adapted to receive the plug I11 of the mechanism I00. Suitable indicia is preferably inscribed on the outer surface of the block 240 for indicating the respective function of the

connection

24I, 243 and 246. One terminal 241 of the connection 2 is connected by a lead wire 248 to one terminal 249 of the connection 246 and by a branch lead wire 250 to one terminal 25I of the connection 243. The other terminal 252 of the connection MI is connected by a lead wire 253 to the other terminal 254 of the connection 246. The lead wire 2I6 connects one terminal of the switch unit 208 to the lead wire 253 while the lead wire 2| 1 con could also be used to nects the other terminal of the switch unit 208 to the other terminal 255 of the connection 243.

Should the burner supplied from the outlet 3 not require a controlled means to supply addi-- tional air to the burner for increased fire operation thereof such as a pure natural draft burner, the switch mechanism IOI may be omitted and the plug II'I would in that case be attached directly to the female end 242 or to any convenient house receptacle of the proper voltage.

In Fig, 10 there is shown a schematic representation of the invention having a single valve member II, the valve member 69 being omitted. As far as possible, like parts are designated with the same numerals as are used in the other figures. Current from a suitable source is supplied through the lead wires 256 to the fan unit 245 and through lead wires 248 and H4 to one side of the primary coil of the transformer unit I54. The other side of the current supply is connected by lead wire through lead wire 2I6 to one terminal of the switch unit 208 and through lead wire I15 to the other terminal of the primary coil of the transformer unit I64. The lead wire 2 connects the other contact member of the unit 208 to the fan unit 245.

The operation of the apparatus is as follows: With the parts positioned as shown in the drawings, the temperature of the space heated by the burner is at or above the predetermined desired degree of temperature. As the space temperature falls, the thermostat I'I3 acts to complete the electrical circuit of the transformer second ary and current will flow through lead wires I68 and I12 the thermostat I13, lead wires I12: and

IGI, the heater I50 and lead wires I60 and I38 back to the other side of the secondary coil of 1 the transformer unit IIS4.- The current flowing through the heater I59 acts to heat the cylindrical portion I53 of the bimetallic element I48 so that the lip portion I54 exerts a progressively decreasing force against the-connecting rod I28 to cause the valve member II and/or 59 to move upwardly. In the schematic drawing of Fig. 10, the lip portion I54 acts directly on the leg I22 whereas in the actual embodiment of the'valve actuating mechanism I00 the lip portion I54 exerts its force against the horizontally extending connecting rod I28. Upward movement of the valve member II rocks the lever member in a counter-clockwise direction. Such movement of the lever member 209 causes the lower edge of the aperture 232, that is, the shoulder portion 232 to engage the underside of the abutment pin 233 which acts to rotate the bell-

crank lever members

223 and 224 in a counter-clockwise direction about the fulcrum member 20?. Movement of the

lever members

223, 224 moves the bridge member 225 more directly into alignment with the abutment member 226 thereby compressing the spring 228 sufficiently so that the spring 228 exerts an increasing downward component of force to push in the push button 2I5 to establish a circuit between the lead wires 2I8 and 2". Upon closure of the circuit by the switch unit 208, current flows from the lead wire 250 through the fan unit 245, through the wire 2I'l, switch unit 208 and lead wire 2I6, back to the lead wire 251 to cause the fan unit 245 to supply the additional air required by the additional fuel supplied by the valve member I I through the outlet 3 to the burner. The valve members I! and 68 are shown in Fig. 2 as' being set for substantially the same rate of fuel flow. This device operates equally well upon change in relative setting of fuel flow between the valve members II and 85. As far as the mechanism I00 is concerned, the operation of the valve members II and 68 when set at unequal flow rates is accomplished by means of the loose connection of the horizontally extending connecting rod I28 with the legsmotion connection between the lever members 209 and 2I0 and the unitary

movable lever members

228, 224 so that whichever lever member, 209 or 2! is moved farther in the counter-clockwise direction will cause the abutment pin 233 to be moved into the aperture 232 and out of contact with the shoulder portion 232.

It may thus be understood that this invention provides a plurality of separate units which may be assembled by one unskilled in the art to revamp a manually operable burner controlling means into an automatically operable burner controlling means. Furthermore, this is accomplished with only minor changes in the normal household electrical wiring which may be made by the householders themselves.

What is claimed and is desired to be secured by Letters Patent of the United States is:

1. In an apparatus of the character described, a hollow casing having a top wall opening and having an end wall with an aperture therethrough, a lever member fulcrumed in said casing and having an operating portion extending through said aperture, spring means carried within said casing and urging said lever member in one direction, a unitary structure bodily removable through said top wall opening and including a plate-like supporting member, a bimetallic power element carried by the under side of said supporting member within said casing and having an actuating portion engageable with and operable to move said lever member, an electric resistance heater positioned in heat exchange relation with said element, a transformer positioned within said casing and carried by the under side of said supporting member, and means directly connecting together as a unit one terminal of the transformer secondary to one terminal of said heater.

2. In an apparatus of the character described, a, supporting member, a switch unit carried by said member and having a reciprocal operating portion, a lever member fulcrumed on said supporting member, a flexible blade having va portion engaging said operating portion, means under stress intermediate said lever member and said blade and exerting a component of force opposing movement of said lever member in one direction, said stressed means acting upon movement of said lever member in said one direction to exert an increasing component of force on said blade thereby to cause said blade to actuate said switch, and means limiting movement of said lever member, said stressed means acting to maintain said opposing component substantially constant within the range of movement of said lever member.

3. In an apparatus of the character described, a supporting member, a switch unit carried by said member and having a reciprocable operating portion, a fulcrum carried by said member, a

flexible blade member engageable with said pormember and said lever-portion,

, and means determining said with said to actuate said switch unit pression between said lever portion and said blade member, means holding the end portions of space positions on said blade said lever ac ing upon movement about said fulcrum to pivot said spring about said blade holding means thereby to decrease its length, said spring having its rate of increase in force with decrease in length so related to the angle formed between said spring and said blade that its component of force tending to flex said blade increases and its component of force tending to' oppose movement of lever remains substantially constant throughout the range of movement of said lever, range of movement.

4. In an apparatus of the character described,

a supporting member, a lever fulcrumed on said member, a switch unit secured to and movable direction, an adjustable stop member carried by lever, means urging said unit in one" said supporting member and limiting movement of said unit by said urging means, said unit having a reciprocably movable actuating portion, a fulcrum member rigid with said unit and spaced from said actuating portion, a second lever fulcrumed on said fulcrum member and having a portion overlying and spaced from said actuating portion, a spring, means holding. one end of said spring in operative engagement with said actuating portion, and means holding the other end of said spring against movement relative to said lever portion, said spring exerting a force opposing movement of said second lever and acting upon movement of said second lever actuating portion.

. second-named lever against 5. In an apparatus of the character described,

a supporting member, a lever fulcrumed on said member, a switch unit secured to and movable with said lever, means urging said unit in one direction, an adjustable stop member carried by said supporting member and limiting movement of said unit by said urging means, said unit hav. ing a-reciprocabiy movable actuating portion, a fulcrum member rigid with said unit and spaced from said actuating portion, a second lever fulcrumed on said fulcrum member and having a portion overlying and spaced from said actuating portion, a spring, means holding one end of said spring in operative engagement with said actuating portion, means holding the other end of said spring against movement relative to said lever portion, said spring exerting a force opposing movement of said second lever and actin upon movement of said second lever to actuate said switch unit actuating portion, and stop means rigid with said switch unit for limiting movement of said second lever.

6. In an apparatus of the character described, a supporting member, lever fulcrumed on said member, switch unit secured to and movable with said lever, means urging said unit in one direction, an adjustable stop member carried by said supporting member and limiting movement of said unit by said urging means, said unit having a reciprocably movable actuating portion, a fulcrum member rigid with said unit and spaced from said actuating portion, a second lever fulorumed on said fulcrum member and having a portion overlying and spaced from said actuating portion, a spring, means holding one end of said spring in operative engagement with said actuating portion, means holding the other end of said spring against movement relative to said lever portion, said spring exerting a force opposing movement of said second lever and acting upon movement of said second lever to actuate said switch unit actuating portion, a third lever fulcrumed on said fulcrum member and having an aperture therethrough, and an abutment carried by said second lever and extending into said third lever aperture, said abutment being appreciably smaller than said third lever aperture to rovide lost-motion between said second and said third levers, said third lever being'operable upon movement to engage said abutment for movement of said second lever bysaid third lever. 7. In an apparatus ofthe character described,

a longitudinally reciprocable operating rod, a spring aligned with and tending to move said rod in one direction, a cam cooperable with and for adjusting said rod against the force of said spring. a lever engageable with said rod, a switch unit having a reciprocable operating member, a lever engageable with first-named lever, and a bodily movable spring interposed between said reciprocable switch operating member and said second-named lever, said bodily movable spring being so positioned and supported that it acts at an acute angle on said switch operating member and exerts a component of force against said second-named lever such that said bodily moveable spring holds said said first-named lever and said first-named lever against said rod. 8. In an apparatus oi the character described, a longitudinally reciprocable operating rod, a spring alined with and tending to move said rod in one direction, a thermostatic power element cooperable with and for adjusting said rod against the force of said spring, electric heating means for said power element, a lever engageable with said rod, 9, switch unit having a reciprocable operating member, a lever engageable with first-named lever, and a bodily movable spring interposed between said reciprocable switch operating member and said second-named lever, said bodily moveable spring being so positioned and supported that it acts at an acute angle on -said switch operating member and exerts a component of force against said second-named lever such that said bodily moveable spring holds said second-named leved against said first-named lever and said first-named lever against said rod. 9. An automatically operable control device comprising supporting means, a, longitudinally reciprocal operating rod guided by said means, control means operable by longitudinal movement of said rod, a. spring acting on said rod and operable to move said rod longitudinally, a bellcrank lever having one arm engaging said rod in opposing relation to said spring. a helical coil compression spring acting on said lever in oppositlon to said first-named spring and substan-' tially longitudinally of said arm and exerting a lesser turning moment on said lever than said first-named spring, a shaft carried by said supporting means and extending through and pivotally supporting said lever, said shaft being positioned closely adjacent the line joining the points 01' engagement of said compression spring and lever and of said lever arm and rod so that the opposing force of said compression spring decreases at a rapid rate upon movement of said rod by said first-named spring, a resilient bimetal controlling member having one end secured to saidsupporting means and having its other end acting on the other arm of said belicrank lever and in conjunction with said compression spring, the combined forces of said bimetal member and of said compression spring holding said rod against movement by said firstnamed spring, and an electric heating means for.said bimetal member to decrease the force exerted by said bimetal member so that said first-named spring will move said rod.

10. An automatically operable control device comprising a longitudinally reciprocal operating rod, control means operable by longitudinal and journaled on said shaft, 2. spring acting on and urging said second lever in the same direction as said second-named spring urges said first-named lever, stop means to limit rotation of said second lever by said third-named spring,

a cross bar loosely interconnecting the other ends of said levers so that said levers can have limited independent rotation, a resilient bimetal member having one end anchored and having its other end bearing against said cross bar, said a bimetal member tending to move away from said cross bar on heating and acting when cold to exert its force in conjunction with said secondnamed and said third-named springs to hold said first-named spring against rod operation and said second-named lever against said stop means, and electric heating means operable to heat said bimetal member so that said first-named spring can overcome said second-named spring and move said operating rod, said bimetal member acting against the mid-point of said cross bar so that the addition of a spring urged control rod acting against said rod engaging end of said second lever with a, force equal to the force of said first-named spring will not increase the force tending to overcome said bimetal member.

11. An automatically operable control device comprising a longitudinally reciprocal operating rod, control means operable by longitudinal movement of said rod, a spring urging said rod longitudinally for operation of said control means, a housing member having a top wall opening, a horizontal supporting plate member in said opening, a transformer having a supporting flange seating against and secured to the underside or said plate member, a stop screw adjustably screwthreaded through said flange and extending downward within said housing member, a guide member for said stop screw and carried by said transformer, a resilient bimetal operating mem-- ber having one end secured to the underside of said plate member, an electric heating coil for said bimetal member and electrically connected to the transformer secondary, a supporting shaft in said housing member, a lever oppose said spring, a spring in said housing member and acting on said lever in opposition to said first-named spring and exerting a lesser turning moment on said lever than said first-named spring, said bimetal member having its free end engaging said lever and acting in conjunction with said second-named spring to hold said rod against movement by said first-named spring, said bimetal member when heated reducing its force against said lever so that said first-named spring can move said rod, and a stop arm on said lever and engageable with said stop screw to limit the movement of said rod by the conjoint force of said bimetal member and said second-named spring.

12. In an apparatus of the character described, a supporting member, a switch unit carried by said member and having a reciprocal operating portion, a lever member having an abutment portion movable transversely to and overlying said operatingportion, an abutment member engaging and operable to transmit movement to said switch operating portion, a coil compression spring operable to actuate said switch operating portion and having its ends positioned between and pivotally supported by said abutment portion and said abutment member, said spring urging said lever abutment portion away from alignment .with' said switch operating portion, and means acting on said lever member and tending to move said abutment portion toward alignment with said switch operating portion so that the force of said coil spring will actuate said switch operating wrtion.

13. In an apparatus of the character described, a supporting member, a switch unit carried by said member and having a reciprocal operating portion, a lever member having an abutment portion movable transversely to and overlying said operating portion, an abutment member engaging and operable to transmit movement to said switch operating portion, a coil compression spring operable to actuate said switch operating portion and having its ends positioned between and pivotally supported by said abutment portion and said abutment member, said spring urging said lever abutment portion away from alignment with said switch operating portion, an operating spring acting on said lever member and tending to move said abutment portion toward alignment with said switch operating portion so that the force of said coil spring will actuate said switch operating portion, and means controlling the movement of said lever member by said last-named operating spring,

WALTER S. LANDON.