US2546611A

US2546611A - Speed regulating mechanism

Info

Publication number: US2546611A
Application number: US568384A
Authority: US
Inventors: Win W Paget
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co
Priority date: 1944-12-15
Filing date: 1944-12-15
Publication date: 1951-03-27
Anticipated expiration: 1968-03-27

Description

March 27, 1951 w. w. PAGET 2,546,611

SPEED REGULATING MECHANISM Filed Dec. 15, 1944 4 Sheets-Sheet 1 1729822202: 2%22 2d fay/ 2.

March 27, 1951 w. w. PAGET SPEED REGULATING MECHANISM 4 Sheets-Sheet 2 Filed Dec. 15, 1944 if a a w v Fm may March 27, 1951 w. w. PAGET 2,546,511

SPEED REGULATING MECHANISM Filed Dec. 15, 1944 4 Sheets-Sheet s m 1220622202; 2 m7 WW 3227112 wj age l M372 H556 fl zio March 1951 w. w. PAGET 2,546,611

SPEED REGULATING MECHANISM Filed Dec. 15, 1944 4 Sheets-Sheet 4 7%. apa? Patented Mar. 27, 1951 ass-an i.

SPEED REGULATING MECHANISM Win W. Paget, Michigan City, ind assignor to Joy Manufacturing Company, a corporation of Pennsylvania Application December 15, 1944, Serial No. 568,384

27 Claims.

My invention relates to speed regulating mechanisms for motor driven compressors, and more particularly to mechanisms for regulating the supply of operating fluid to driving engines for compressors.

Engine driven compressor systems are ordinarily provided with some form of mechanism for regulating the supply of operating fluid to the engine in response to the pressures in a receiver to which fluid is supplied from the cornpressor. It is desirable that the mechanism operate to cause a gradual reduction in the engine speed as the receiver pressure increases through a predetermined range. When the pressure reaches the upper limit of the range, the compressor is unloaded and the driving engine is slowed down to an idling speed. On' reduction of the receiver pressure to a predetermined lower value, the driving engine is speeded up and the compressor isreloaded.

In a preferred embodiment my invention con-' templates the provision of a mechanism which responds to pressures in a receiver for regulating the supply of operating fiuid to an engine so as to vary the speed of the latter in the manner described above, and operating to control the flow of fluid relative to an unloading device when the desired pressure is reached. A speed responsive governor is provided for urging a. control element in a direction to reduce the supply of operating fluid to the engine, and yieldable means resist the action of the speed responsive governor by amounts varying with the receiver pressure. A pressure responsive device is subjected continuously to the receiver pressures and operates as the pressure increases to reduce the resistance oilf'ered by the yielding means to the action of the governor. On predetermined movement of the pressure responsive device, valve means are operated to supply pressure fluid to unloading means for the compressor and to another pressure responsive device which moves the control element to a position effecting operation of the engine at an idling speed. In one form of the invention, when the same is utilized in a system including a separate slow-down device, the valve means may operate to supply pressure fluid to a pressure responsive device for preventing reloading occurring due to there being a reduction in the forces exerted by the flyballs, as a result of the slowing down of the engine by the slow-down device, to such a degree that the control element would not be prevented by the forces usually then acting on it from moving to a reloading position.

An object of my invention is to provide improved means for regulating the supply of operating fi'uid to an engine driving a compressor. Another object is to provide improved means for varying the supply of operating fluid to the driving engine for a compressor in response to the pressures in the compressor discharge line. Still another object is to provide an improved mechanism for reducing gradually the speed of a driving engine for a compressor as the discharge pressure of the latter increases through a predetermined range and operating at a pressure above the upper limit or the pressure range for effecting an unloading of the compressor and a slowing down or" the engine to an idling speed. Yet an other object is toprovide an improved regulating means which operates to oppose a variable resistance to the action of a speed governor, such resistance varying as there occur variations in the discharge pressures of a compressor. Still another object is to provide an improved regulating mechanism which operates to reduce the resistance to operation of a speed governor in a speed reducing direction as the discharge pressure of a compressor increases. Other objects will appear in the course of the following description.

In the drawings there are shown for purposes of illustration two forms which my invention may assume in practice.

In these drawings:

Fig. 1 is a side elevational view of an internal combustion engine having my improved regulating mechanism in its preferred form associated therewith.

Fig. 2 is an enlarged vertical sectional view of the improved regulating mechanism shown in Fig. i.

Fig. 3 is a central sectional view through a cylinder head and a portion of a cylinder of a compressor adapted to be driven by the engine shown in Fig. I.

Fig. 4' is an enlarged vertical sectional view taken on the plane or" the line i---iof Fig. 1.

Fig. 5 is a fragmentary sectional view taken on the plane of the line 5-5 of Fig. 4.

Fig. 6 is a schematic diagram showing the regulatin mechanism connected in a control system for the compressor and its driving engine.

Fig. 7 is a view like that of Fig. 1 showing another form of my improved regulating mechanism connected to an internal combustion engine.

Fig. 8 is an enlarged vertical sectional view of the regulating mechanism shown in Fig. '7.

Fig. 9 is an enlarged fragmentary sectional view taken on the plane of the line 9-4: of Fig. 7.

10 is a fragmentary sectional view taken on the plane of the line ifi-II] of Fig. 9.

Fig. 11 is a schematic diagram showing the regulating mechanism of Fig. 8 connected in a compressor control system.

In Figs. 1 to 6 my improved regulating mechanism is shown in its preferred form associated with an internal combustion engine for controlling the supply of operating fluid to the latter in desired relation to variations in pressure in a receiver of a compressor system. The internal combustion engine, generally designated I, has a carburetor 2 containing a throttle valve 3, Figs. 1 and 6, which is regulated by my improved regulating mechanism, generally designated l. The power shaft of the engine is operatively connected by means, not shown, to a compressor having pistons one of which is shown at 5 and effects reciprocation of the latter in a bore 8 of a compressor cylinder 9. It will be understood that other compressor cylinders containing pistons connected for reciprocation by the power shaft may be provided if desired and will ordinarily be used. Fluid is admitted through an intake passage I I and past an inlet valve 52 to the cylinder bore 8 where it is compressed, and thereafter discharged past a discharge valve IE to a passage l5 which is connected by suitable connections, not shown, to a receiver I6 shown in Fig. 6. The cylinder has a head 58 connected thereto, as by bolts IQ, and attached to the head, as by bolts 2Q, is a member 22 having a chamber 23 which receives a piston 25 carrying a plate portion 26. Rods 21 are connected to the plate portion 26 and extend through openings in the cylinder head to engage the inlet valve i2 for unseating the latter and effecting an unloading of the compressor cylinder when the piston 25 is subjected to pressure fluid. The piston 25 is normally held in its raised position by a spring 28 and is adapted to be forced to its lower position against the action of the spring 28 by pressure fluid supplied to the chamber 23 through a conduit 30.

The improved regulating mechanism 5 comprises a block 32 having a recess 33 containing a bellows device 34. Connected to the block at the open end of the recess is an annular member 36 having a sleeve portion 38 at its inner edge projecting axially into the bellows device 3d. Clamped between the member 36 and the block 32 is an annular plate member 58 to which one end of the bellows device 34 is connected, as by brazing or soldering. The other end of the bellows device is connected in a similar manner to a member 42 having a sleeve portion 43 which is reciprocably received within the sleeve portion 38 of the member 36. The space within the recess 33 surrounding the bellows device 3 5 has pressure fluid supplied to it from the receiver past a check valve 44 which is movable to a position for permitting free admission to the recess 33 and is adapted to seat on a projecting seat 45 surrounding a recess 46 in the block 32. Pressure fiuid is supplied to the recess 33 through a passage 4! which is connected in communication" system. The block 32 is provided with a projecting portion 50 to which a lever 5| is pivotally connected at a point between its ends, as at 53. Pivotally connected to the lever 5i at a point 55 below the pivot point 53 and in alinement with the sleeve portion 43 of the member 42 is a pin 56 which extends through the sleeve portions 33 and i3 and engages the member 12 for holding the latter normally in engagement with the inner end of the recess 33. The block member 32 is also provided with a downwardly projecting portion 58 having an opening receiving an eyebolt 59 carrying lock nuts 6%, and a spring 62 is connected at one end to the eyebolt 59 and is connected at its other end to the lower end of the lever 5|.

Keyed to a shaft 63 projecting from the engine housing 64 adjacent the block 32 is a control lever 65 having a portion 56 projecting downwardly below the shaft 83, and a spring 8? is connected at one end to the lower end of the lever 5| and at its other end to an eyebolt 68 extending through an opening between the ends of the portion 6% of the control lever and held in place by a lock nut 69. Extending through another and lower opening in the projecting portion 58 of the block 32 at a point below the eyebolt 59 is another eyebolt Iii having lock nuts II, and a spring I3 is connected between this eyebolt and the lower end of the projecting portion 66 of the lever 65. Formed integral with the control lever .65 adjacent the shaft 63 is a transversely projecting portion I5 which is adapted to be engaged by a stem 16 formed on a piston i3 slidably received within a bore 8! formed in an enlarged portion 8i at the outer end of the projecting portion 59 on the block 32. The piston I8 is normally held in its raised position by a spring 82 which acts between the piston and an annular member 35 supported by a split ring 87' fitting within an annular groove adjacent the lower end of the bore 86. When pressure fluid is supplied to the bore 8!} at the upper side of the piston I8, the latter is moved downwardly against the action of the spring 82 and engages the projecting portion '55 of the lever 65 for swinging the latter in a counter-clockwise direction. Carried by the lever E5 is a bolt ilii which is engageable with the side of the enlarged portion M for limiting the swinging of the lever in a counter-clockwise direction. The bolt 98 is adjustable to various positions and may be locked in place by a lock nut 92. A lever 96 is pivotally supported at its lower end, as shown in Fig. 4, upon the shaft 63, and its upper end is connected to a rod 95 which is attached to an arm 96 connected to the throttle valve 3. The upper end of the lever 65 is provided with a transversely extending portion 93 having an arcuate slot 99, and a pin I is fixed in an opening in the lever S I between the ends of the latter and extends through the slot 99. The

levers

65 and 94 are adjustable angularly relative to each other by reason of the slot 99, and a wing nut I0! threaded on the pin NIH is adapted to clamp the levers in the desired adjusted positions.

Formed in the block 32 above the recess 33 are stepped bores H33 and Hi l providing at their juncture a valve seat H35 which is engageable by a cup-shaped valve member I89 slidably received within the larger bore I03. The valve member I05 has grooves Iill extending longitudinally thereof in its outer surface for connecting the bores I03 and I04 in communication with each other when the valve member is unseated. A

coring 1% acts between a plug I89 closing the outer end of the bore E83 and the valve member 1% for urging the latter toward the seat Hi5. Threaded into an opening in the block 32 at the outer end of the bore 594 is a member i It providing a valve seat Hi, and a valve member H2 has a head portion H3 engageablewith the seat i H and a winged stem l M extending through an opening in the member H9 and engageable with the valve member 96 for unseating the latter when the head portion H3 is caused to engage the seat. The valve member I i2 is normally held in a position with its head portion H3 unseated, by the action of the spring H38 on the valve member i853. Threaded into an opening in the upper end of the lever M is a pin H5 which is engageable with the head portion I 13 of the valve member l l2 for moving the latter to unseat the valve member We and to cause the head portion H3 to engage its seat when the lever i swung in a counter-cloclzwise direction. When the head portion I I3 is unseated, the bore ifi i is connected through the spaces between the wings on the stem lid and past the seat Hi to atmosphere. The bore M23 is connected directly in communication with the receiver it by a conduit H6, and the bore 194 is connected by a conduit l i? through a valve mechanism H8 to a conduit H9 which communicate with the conduits 38 leading to the compressor unloading pistons 2-5. As shown in 6, two conduits 3B are provided, the compressor in this case having two cylinders, each having an unloading mechanism. In many units, four or more cylinders may be used. The valve mechanism i It is of a standard type and permits Extending longitudinally is slidably supported at one end in an opening 7 any suitable manner from the power shaft of the engine i. The member 130 is provided with a slot 535 into which the shaft 527 projects, and fiyweights i-35 are pivotally connected to the member i3 2 and have inwardly projecting portions Hi8 which are adapted to engage the end of the shaft i2 1 for forcing the latter longitudinaily to left, in Fig. 5, as the weights swing outwardly. Fixed to the shaft i2? is a spoolshaped member lSri having an annular groove [39 into which the crankpin i2 projects. It will be seen that the movement of the rod l2? by the outward swinging of the weights l35 causes the spool-shaped member I38 to move the crankpin i26 and so rotate the shaft 63 in a direction to swing the control lever 65 in a counter-clockwise direction, as shown in Fig. 2, against the action of springs 57 and 73.

The operation of the regulating mechanism is as follows: When the pressure in the receiver increases to a-va-lue sufficient to start to compress 5 the bellows device 34 and swing the lever 51 against the action of the spring 62', there will be, on swinging of the lever 5!, a reduction in the force offered by the spring 6? for holding the control lever t5 against rotation in a counterclockwise direction. The resistance offered by the spring 62 to the swinging of the lever 5! may be regulated by adjusting the eyebolt 59, this adjustment being made so that the bellows device 34 operates to initiate a slowing down of the engine at the'desired discharge pressure. A reduction of the force holding the lever 65 against swinging in a counter-clockwise direction results in an outward swinging of the weights I35 and a movement of the shaft i2! in a direc tion to effect rotation of the shaft 63 in a counterclockwise direction. The control lever 65 is swung with the shaft 63 and causes the lever as to swing with it and move the rod in a direction to partially close the throttle valve 3 of the engine. As the receiver'pressure continues to increase, the control lever 65 continues to swing in a direction to reduce the supply of operating fi-uid to the engine. After the lever 5! has been swung a predetermined distance by the bellows device 3a, the pin I I5 carried by the upper end of the lever engages the head portion H3 of the valve member H2 and presses the latter against the valve member [06, which has been held seated by receiver pressure acting in the bore I93 against its left-hand end and by the spring [08. When the receiver pressure has increased by an amount, depending on the relative areas of the valve member We and the bellows 3t and the strength of the spring we, sufiicient to unseat the valve member 5635, the lever 5 i will be swung further in. a counter-clockwise direction by the bellows 3t unseating the valve member iii-E5 and seating the valve member H2 to cut oif communication between the bore its and the atmosphere. Pressure fluid then flows from the receiver it through the conduit M5 to the bore m3 where it passes through the grooves I-lll to the bore Hi l. The pressure fluid passes from the bore its through the passage E2! to the bore 86 where it acts onthe piston 18 and forces the latter downwardly to engage the projecting portion 15 of the control lever 65 and effect a swinging of the latter in a counter-clockwise direction until the throttle valve for the engine has restricted the flow of fluid to such an extent that the engine operates at an idling speed. The pressure fluid also passes from the bore H34 through the conduit l H, the valve mechanism H8 and the conduit Hi) to the conduits 3i. leading to the unloading mechanisms for the compressor cylinders. The swinging of the control lever 65 by the piston 18 causes a substantial increase in the tension of the spring 67 and makes it necessary that the pressure in the receiver drop somewhat before the lever 5! will be able to swing in a clockwise direction about its pivot pin 53. It will further be noted that the supply of receiver pressure to the bore Hi4 resulted in an equalizing of the pressures at opposite ends of the valve member Hi6 and a reduction in the force which resisted the motion of the lever 5| in a counter-clockwise direction so that the seating of valve H2 readily took place. When this valve is seated receiver pressure acts against an area on the valve member H2 equal to the area inside its seat, and exerts a force upon this valve tending to push the pin H5 to the right in Fig. 2. This means that a reduction in receiver pressure in addition 7 to that needed to compensate for the increased tension of spring 61 will be required before the lever i will swing again in a clockwise direction, because to unseat the valve I08 took more force than is required to keep valve H2 seated. When the receiver pressure drops the requisite amount and the lever SI swings in a clockwise direction under the action of spring 52, the head N3 of the valve member H2 will be disengaged and the latter will be unseated by the action of the spring I68 on the valve member IE6. The unseating of the valve member H2 causes the bore Itfi to be vented to atmosphere so that pressure fluid escapes immediately from the space above the piston "I8 through the passage I2I to atmosphere. The piston i8 is moved upwardly by the spring 32 out of engagement with the projecting portion E5 of the control lever and the latter is caused to swing by the springs 67 and 13 in a direction to increase the supply of operating fluid to the engine. The engine speeds up, causing the weights I35 of the governor to swing outwardly against the action of springs E1 and I3 until the forces on the control lever are balanced, the position assumed by the control lever being determined by the pressure acting on the bellows device 34. The escape of pressure fluid from the unloading mechanisms of the compressor will be restricted by the valve mechanism H8 so that a reloading of the con pressor will not take place until the speed of the engine has been increased.

In Figs. 7 to 11 there is shown an internal combustion engine M5 having the supply of operating fluid delivered thereto controlled by another form of regulating mechanism, generally designated IM. This regulating mechanism includes a block I48 having a recess H39 containing a bellows device I56. Connected to the block at the open end of the recess is a member I52 having a sleeve portion I53 extending axially within the bellows device I58. Clamped between the member I52 and the block is an annular plate I55 to which one end of the bellows device I553 is connected, as by brazing, and the other end of the bellows device is connected in a similar manner to a member [d8 having a sleeve portion I5? slidably received within the sleeve portion I53. Pivotally connected at a stationary point IE5 is a lever Itl having a pin I62 pivotally connected thereto at a point in axial alinement with the sleeve portion I53, and this pin extends through the sleeve portion I53 into engagement with the member I53. The block I68 is provided with an upwardly projecting portion I64 carrying an eyebolt I85 to which one end of a spring I67 is connected, and the opposite end of the spring I5? is connected to the upper end of the lever ifil for resisting swinging of the latter by the bellows device I50. The space in the recess I59 surrounding the bellows device I58 is connected directly in communication with the receiver through a conduit I59 which might if desired be supplied with any suitable check valve arrangement similar to the valve device id, 45, P. The pressure fluid acting on the exterior of the bellows device I55 tends to compress the latter and swing the lever ISI in a clockwise direction against the action of the spring IB'I.

Keyed to a shaft I12 projecting from the engine housing is a control lever IId which is con ected by a spring H5 to the upper end of the lever IGI. The control lever lid is connected at its upper end to a rod I'ii which is attached to an arm I18 fixed to a throttle valve I79 for the engine.

-, ing with the atmosphere.

Movement of the control lever I'M in a clockwise direction causes the throttle valve I19 to be actuated in a manner LO restrict the fiow of operating fluid to the engine. The control lever I14 is provided with an adjustable member I which is engageable with an abutment surface I82 On the engine housing for limiting swinging of the control lever in a clockwise direction. Supported by the upwardly projecting portion ltd of the block I 38 is another eyebclt its to which one end of a spring I85 is connected, and the opposite end of the spring I85 is connected to the control lever Formed in the block I48 beneath the recess I 18 is a recess I3? containing a member I88 having stepped bores I89 and I93. Slidably received within the larger bore I39 a valve member IIH which is engageable with the seat-providing shoulder formed at the juncture of the bores I89 and I99 for cutting ofi communication therebetween. A spring I92 acts between a plug as closing the outer end of the recess I87 and the valve member I I for urging the latter into an engagement with the seat-providing shoulder between the bores. The member I83 is also provided with a bore I5 which slidably receives a plunger I96 having a valve portion I91 for controlling the rlow of fluid from the bore III J through a port I82 to passages res communicat- Projecting from the valve portion It is a stem 2m which extends through the port I38 and is engageable with the valve member for moving the latter toward its open position when the valve portion i9? is moved toward its seat. Formed in the walls of the bore I89 adjacent the juncture of the bores I88 and I83 is an annular groove 2 33, and ports 264 formed in the valve member IQI connect the space in the bore I39 at the left of the valve member IBI in communication with the annular groove 283. The space in the bore I39 at the left of the valve memher Ifii has pressur fluid supplied thereto from the receiver through a conduit When the valve member 58! is unseated fluid flows from the groove 2&3 to the bore I95 where it enters a passage 296 and is conducted to a conduit 25? which is connected, as shown in Fig. ll, to conduit-s 288 and 299. Conduit 2%8 communicates with a cylinder member 2! I which contains a suitable fluid actuated means, not shown, such as a piston, which is connected to an arm ZIZ of a throttle valve 2E3. On supply of pressure fluid to the cylinder member H I, the arm H2 is actuated to move the throttle valve 2I3 in a closing direction. The throttle valve 2I3 is moved by the device ill I, 2E2 to slow the engine down to a desired minimum idling speed. The conduit 299 is connected through a valve mechanism to a conduit 2H5 which communicates with conduits 3i! leading to the unloading mechanisms for the compressor cylinders. The valve mechanism 2E5 operates in the same manner as the valve mechanism H3 shown in the first form of the invention, that is, to permit a free flow of fluid to the unloading mechanism and to restrict the flow in the opposite direction. The lever 16E is provided with a downwardly projecting portion SIS carrying an adjustable member 2H3 which is engageable with the plunger I96 for forcing the latter in a direction to cut oil" communication between the bore I56 and the atmosphere and to move the valve member IIII to its open position so as to supply pressure fluid to the bore I90.

When the valve IE5 is unseated, the pressures tend to equalize at its opposite ends and thus the force that opposed movement of pin ZIQ to unseat the. valve is reduced, and replaced by a.

smaller force equal to that exerted by receiver pressure on'an area equal to the cross-sectional area of the port I98 and that due to sprin I92, so that valve ISI opens smartly, and ther will be needed a drop in receiver pressure below that required to unseat valve" I GI to prevent its closing again.

The shaft I12 extends, as shown in Fig. 9,

through a bushing 224 fixed in an opening in the wall of the engine housing, and the inner end of the shaft I12 carries a crank 225 having a pin 226 which extends into an annular groove 22? in a spool-shaped member 228 slidably mounted on a shaft 229 extending longitudinally through the housing of the engine. Suitably connected to one end of the shaft 2253 is a gear 233 meshing with a gear 23I which is driven in any suitable manner from the power shaft of the engine. Ex-

tending longitudinally through the shaft 2291s a bore 232 in which a' rod'2li4 is slidably contained; and this rod is connected at one end to the spool-shaped member 228 by a pin 235 which extends through an elongated slot 236m the shaft 22$. The other end of the rod'234 projects into a slot 239 formed in the shaft 229 and is engageable inwardly projecting portionsZAt formed on flyweights 24! pivotally connected to the shaft 229. As the flyweights swing outwardly about their pivotal connections to the shaft, the rod 234 is forced to the right in Fig. 9 through the bore 232and causes the spool-shaped member 228to slide along the shaft 229: This-movement'of the spool shaped member 228 actuates the pin 22% to rotate the shaft I12 in a direction to efiect a swinging of the control lever I14'in a clockwise direction, as shown in Fig. 8.

The control lever I14 is provided'with aportion 245 projecting-downwardly below the shaft I12, and this portion of the shaft is engageable by a piston 246 which is slidably mounted in a bore 241 of a'cylinder 248.- Pressure fluid is'supplied to the bore 241 at itsinner end through a conduit 250 which is connected in communication with the conduit 203; When pressure-fluid is supplied to the bore 241, the piston 246' is forced outwardly against the portion 245 of the control lever for holding-the latter in a position with its adjustable member IBII engaging the abutment surface I82.

The operation of this regulating mechanism is similar to that of the first form of the invention. When the receiver pressure increases to a value suflicient to start to compress the bellows device I56 and swing the lever MI in a clockwise direction against the action of the spring I61, the resistance offered by the spring I15 to a swinging of the control lever I14 in a clockwise direction will. be reduced. The flyweights 24I of the speed governor will then operate to move the rod 234 and efiect a rotation of the shaft I12 in a clockwise direction, as shown in Fig. 8. The control lever I1 will swing with the shaft I12 against the action of the springs I and I 85 and will operate the rod I11 to move the throttle valve I19 toward its closed position for restricting the flow of operating fluid to the engine. When the lever ISI is swung by the bellows device I50 to a point where the plunger I96 is moved by the adjustable member 2H9 to a position seating the valve portion I9? and unseating the valve I9i, the venting of the bore I90 will be cut off and pressure fluid will be supplied fromthe receiver past the valve member I9I to the bore I90. The.

pressure fluid-will then. flow 'fromthe bore-190' through the passage 206 to: the ccnduit2 01 where". itwill bG'COIldllCtBdtO. the conduits 2G8, 209 -andI 2541; Pressure fluid .entering the conduit 208 will be conducted to thecylindermember 2 I I where. it

acts to effect. aclosing of: the throttle .va1ve'2I3 until '1 the engine operatesiat anidlingspeed:

The=conduit 299 will conduct the pressure fluid through'the valve mechanism 2 I5 to the conduit.

2 I6 where-it is conducted to the conduits 30 leading: to the unloadingmechanisms for the com-- pressor, cylinders andeifects an unloading of the latter. The operation .of the engine at an idling speedicausesthe speed'governor to reduce its forceitending to hold thecontrol lever I14 ina' position :for restricting'the flow of operating fluid to therenginepast' the throttle valve I19, and, if

nothing were provided for'holding the control lever in its valve-restricting position, the springs I15 and I85 would operateto swing the control lever in' a counter-clockwise direction because the speed responsive governor exerted force would bereduced. This would not increase the'engine speed, because valve 2| 3 limits that. of the control lever in this counter-clockwise-direction would result, however, in a reduction in" the'force tending to hold'the lever IfiI againstmovement in a counter-clockwise direction, and the lever I6I would then swing in this directionand release the plunger I96, cutting off the flow of pressure fluid to the unloading means and to the throttle closing means. Such movement of the control lever is prevented, however, by reason of the fact that pressure fluid is delivered through the conduit 250 to'the cylinder bore 241 where it acts on the piston 246 and forces the latter against the projecting portion 245' of the control lever for holding the latter against movement in a counter-clockwise direction. the control lever I14 were swung by the speed governor, by the time the plunger 246 becomesoperative, to a position in which its adjustablemember IBil engages the abutment surface I82,

there would be no further swinging of the control lever I1 1 by the piston 246 on supply oi pressure fluid'to the latter, and the tension of the spring I15 would remain the same as it was at the moment the lever iGI forced the plunger I96 to its innermost'position. Under this condition,

the pressure acting on the bellows device I50 even then be required, because of the change: in-

forces involved on the opening of valve I9I. If the member we on the control lever I14 and the member 2I9 on the control lever IBI new ad justed that the plunger I96 is forced inwardly by the lever ISI and unseats the valve IQI before he member I engages its abutment surface,

the supply of pressure fluid to the cylinder. mem-' her 248 will cause the piston 243 to act against the portion 255 of the-lever I14 and swing the latter until its member I80 engages the. abute ment surface I$2 and will hold: the lever. I14. against eounter-clockwise movement. and,, as.

above noted, prevent the lessened forceexerted by the flyballs at the slower speed caused by the" closing movement of the'valve 2I3 from permit-- Movement ting the lever I'M from moving back and reducing the tension of spring H enough to permit repositioning of valves I9l and 191 to cause reloading without a reduction in receiver pressure taking place. Desirably the parts will be so adjusted that the movement of the lever 114 to bring the stop element against the stop surface 582 will involve a small increase in the tension of the spring I since the lever l 6! will be held by its engagement with the plunger 196 against swinging in a clockwise direction. With this arrangement, the pressure acting on the bellows device l5 3 will need to drop to a somewhat lower value before the lever it! will be swung in a counter-clockwise direction to permit the plunger I96 to move outwardly and vent the conduits 208, 2439 and 25s and effect a speeding up of the engine and a reloading of the compressor.

As a result of my invention there is provided improved regulating mechanism which operates to reduce gradually the supply of operating fluid to the drivin engine for a compressor as the discharge pressures of the latter increase through a predetermined range, and which operates at a pre-determ" ed maximum discharge pressure for supplying pressure fluid to efifect a slowing down of the engine to an idling speed and an unloading of the compressor. It will be noted that the regulating mechanism is provided with various adjustable means whereby it will operate to reduce the speed of the driving engine gradually through any desired pressure range and will eiiect a slowing down of the engine to an idling speed and an unloading of the con pressor when any desired maximum pressure is reached. A speeding up of the engine and a reloading of the compressor may also be obtained within reasonable limits on a drop in pressure to any desired value. A

By the term operating fluid it will be understood that I intend to describe, but without limitation thereto other than may be required by the prior art, the combustible mixture exploded in gasoline engine cylinders, and vaporized or other liquid fuels utilized in Diesel engines; and my invention is not to be understood as limited to use with any particular operating fluid.

While there are in this application specifically described two forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration, and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope or" the appended claims.

What I; claim as new and desire to secure by Letters Patent is:

l. A speed regulating mechanism for an engine driven compressor comprising, in combination, means for controlling the supply of operating fluid to the engine, a speed govern-or for urging said controlling means in a direction to reduce the supply of operating fluid, means for yield ably resisting the action of said speed governor, means responsive to compressor discharge pressure for varying the resistance ofiered by said yieldable means progessively to reduce such resistance as compressor discharge pressure increases between predetermined limits, means for subjecting said pressure responsive means continuously to compressor discharge pressure, other pressure responsive means for actuating said controlling means in a direction to reduce the supply of operating fluid, and means for 12 supplying compressor discharge pressure to said last mentioned pressure responsive means automatically only when the discharge pressure reaches a predetermined maximum value.

2. A speed regulating mechanism for an engine driven compressor comprising, in combination, means for controlling th supply of operating fluid to the engine, a speed governor for urging said controlling means in a direction to reduce the supply of operating fluid, means for yieldably resisting the action of said speed governor, means responsive to compressor discharge pressure for varying the resistance oiiered by said yieldable means progressively to reduce such resistance as compressor discharge pressure increases between predetermined limits, means for subjecting said pressure responsive means continuously to compressor discharge pressure, pressure responsive means for actuating said controlling means in a direction to reduce the supply of operating fluicLmeans including a valve member for controlling the supply of pressure fluid to said last mentioned pressure responsive means, and means controlled by said first mentioned pressure responsive means for controlling said valve member.

3. A speed regulating mechanism for an engine driven compressor comprising, in combination, means for controlling the supply of operating fluid to the engine, a speed governor for urging said controlling means in a direction to reduce the supply of operating fluid, means for yield- I ably resisting the action of said speed governor,

means responsive to compressor discharge pressure for varying the resistance oiiered by said yieldable means progressively to reduce such resistance as compressor discharge pressure increases between predetermined limits, means for subjecting said pressure responsive means continuously to compressor discharge pressure, pressure responsive means for actuating said controlling means in a direction to reduce the supply of operating fluid, means including a valve member movable to an open position for supplying pressure fluid to said last mentioned pressure responsive means, and means controlled by said first mentioned pressure responsive means for controlling said valve member, operative to move said valve member to its open position when said first mentioned pressure responsive means is subjected to a predetermined maximum discharge pressure.

4. A regulating mechanism for an engine driven compressor having fluid actuated unloading means comprising, in combination, means for controlling the supply of operating fluid to the engine, a speed governor for urging said controlling means in a direction to reduce the supply of operating fluid, means for yieldably resisting the action of said speed governor, means responsive to compressor discharge pressure for varying the resistance offered by said yieldable means progressively to reduce such resistance as compressor discharge pressure increases between predetermined limits, other pressure responsive means for actuating said controlling means to reduce the supply of operating fluid, and means for supplying compressor discharge pressure to said last mentioned pressure responsive means and to the compressor unloading means when the discharge pressure reaches a predetermined maximum value.

5. A. regulating mechanism for an engine driven compressor having fluid actuated unloading means comprising, in combination, means aseegarp for. controlling; the: supply of-operatin fluid: to. the engine, a speed governor for urgingv said controlling-means in a direction to reduce the supply of operating. fluid, means for yieldably resisting the action ofnsai'd speed governor, means responsive to compressor discharge pressure'for varying the resistance ofiered by said yieldable means progressively to reduce such resistance as. compressor dischargepressure increases between predetermined limits, pressure'responsive means for actuating said controlling means to reduce the supply of operating iluid, means for conduct-- ing pressure fluid to sai last mentioned pressure-- responsive means and to the compressor unloading means, means including a valvewmember for controlling the supply of pressure fluid to-saidconducting means, and means actuated-by said firstmentioned pressure responsive means. for controlling said valve member.

6. A regulating mechanism for an enginedriven compressor having fluid actuatedunload' ing means. comprising, in combination, means. for. controlling; the supply'of operating fluid. to: the engine, a. speed governor for urging; said controlling meansin a direction to reduce the supply of operating fluid, means for yieldably resisting the action of said speed governor; means responsive-to compressor discharge pressure for: varying. the resistance offered by yieldable means progressively to reduce such resistance: as compressor discharge pressureincreases be tween predetermined limits, pressure responsive: means for actuating said controlling means to reduce the. supply of operating fluid, means for conducting pressure fluid to said lastmentioned pressure responsive means and to the compressor: unloading means, means'inclu-ding a valve member movable to an open position for supplyingpressure fluidto saidfiuid conducting means, and means actuated by said firstmentioned pressure responsive means for controlling said. valve member, to move saidvalve member toits open position when said first mentioned'pres-- sure responsive means is subjected to a predetermined maximum discharge pressure.

7. A regulating mechanism for an engine driven compressor having fluid actuated unload--- ing means comprising, in combination, means for. controlling the supply of operating fluid to the engine, a speed governor for urging said" controlling means ina direction to reduce the supply of operating fluid, means-ionyieldably' resisting, the action of said speed governor, means responsive to compressor discharge pressure for varying the resistance offered by said yieldablemeans progressively to reduce such resistanceas compressor: discharge pressure increases between predetermined limits, pressurev responsive means for actuating said controlling means tnreduce thesupply of operating fiuid; meansfor m compressor having fluid. actuated: uillOaidll'l'giTOi means comprising, in combination, meansiorr controllingthe supply of operatingfiuid to'the engine, a speed governor for urging, said cone trolling means in a direction to reduce thesupply" said controlling means to reduce the supply of operating fluid, means for conducting pressure.

fluid relative to said last mentioned pressure responsive means and the compressor unloading. means, valvemeans for controlling, the connection of said fluid conducting means to fluid supply and to exhaust, and means actuated by saidfirst mentioned pressure responsive means for controlling said valve means, said last mentioned means operative to position said'valve means for 3 connecting said fluid conducting means to fluid of operating. fluid, means for. yieldably resisting 75" supply when said first mentioned pressureresponsive means is subjected to a predetermined. maximum discharge pressure;

9. A regulating mechanism for an enginedriven. compressor having fluid actuated unloading.

means comprising, in combination, a throttle valve for controlling the supply of operating. fluid to the engine, means including a speed governor for urging said throttle valve towardits closed position, means for yieldably resisting the action of said speed governor, means 'respon.-. sive to compressor discharge pressure for vary.- ing theresistance offeredxby said yieldablameans;

said last mentioned means" operative to reduce.-

the resistance: offered" by said yieldable means as the discharge: pressure increases; pressure responsive means. ioractuating said throttle: valve to reduce the supply of? operating fluid,- and means for supplying pressure fiuid'to said last mentioned. pressure responsive means and to the": compressor.v unl ading means whenthe reaches apredetermined position; means foryieldably resisting the action of said speed governor; means responsive tov compressor discharge pressure for... varying. the resistance offered by saidyieldable-means, said last mentioned means operative to reduce the resistance oiiered by said yieldable means as the" discharge. pressure increases, pressure responsive means foractuating said throttle valve to reduce the supply of operating fluid, means for conductingpressurecfiuid relative to said last-men-- tioned pressure. responsive means and the com-- means to fiuid'supply'and to exhaust, and means" actuated. by said first mentioned pressure responsive means. for controlling'said valve means, said last mentioned means operative at a pre determined. maximum: discharge pressure for connecting said fluid conducting means to fluid supply and operative at a predetermined lower pressure. for connecting said fluid conducting means to exhaust.

11. A. regulating: mechanism for an engine driveniicompressorunit which has fuel regulating means. for. the engine comprising a pair-or" throttle? valves; one in. the intake: and one in.- the carburetor for. the engine, said regulating means comprising-fluid pressure. actuated meansfor controlling'said. second mentioned throttle.- valve; and a speed responsivedevice: and; com-1+ pressor. discharge pressure responsive means; 00

acting in the control of said first mentioned throttle valve, and a valve device controlled by said compressor discharge pressure responsive means for controlling fluid supply to said fluid pressure actuated controlling means for the second mentioned throttle valve.

12. A regulating mechanism for an engine driven compressor having fluid actuated unloading means comprising, in combination, a throttle valve for controllin the supply of operating fluid to the engine, means including a speed governor for urging said throttle valve toward its closed position, means for yieldably resisting the action of said speed governor, pressure responsive means for varying the resistance ofiered by said yieldable means, means for subjecting said last mentioned means continuously to compressor discharge pressure, pressure responsive means operative on the supply of pressure fluid thereto for holding said throttle valve against movement in an opening direction, a second throttle valve for controlling the supply of oper ating fluid to the engine, pressure responsive means operative on the supply of pressure fluid thereto for moving said second throttle valve to a position for effecting an operation of the engine at an idling speed, means for conducting pressure fluid relative to said second and third mentioned pressure responsive means and the unloadirp means, valve means for controlling the connection of said fluid conducting means to fluid supply and exhaust, and means actuated by said flrst mentioned pressure responsive means for controlling said valve means.

13. A regulating mechanism for an engine driven compressor having fluid actuated unloading means comprising, in combination, a throttle valve for controlling the supply of operating fluid to the engine, means including a speed governor for urging said throttle valve toward its closed position, means for yieldably resisting the action of said speed governor, pressure responsive means for varying the resistance offered by said yieldable means, means for subjecting said last mentioned means continuously to compressor discharge pressure, pressure responsive means operative on the supply of pressure fluid thereto for holding said throttle valve against movement in an opening direction, a second throttle valve for controlling the supply of operating fluid to the engine, pressure responsive means operative on the supply of pressure fluid thereto for moving said second throttle valve to a position for eflecting an operation of the engine at an idling speed, means for conducting pressure fluid relative to said second and third mentioned pressure responsive means and the un loading means, valve means for controlling the connection of said fluid conducting means to fluid supply and exhaust, and means actuated by said first mentioned pressure responsive means for controlling said valve means, said last mentioned means operative at a predetermined maximum discharge pressure for actuating said valve means to connect said fluid conducting means tofluid supply.

14. A speed regulating mechanism for an engine driven compressor comprising, in combination, means for controlling the supply of operating fluid to the engine, a speed governor for urging said controlling means in a direction to reduce the supply of operating fluid, means for yieldably resisting the action of said speed governor, means responsive to compressor discharge pressure for varying the resistance oflered by said yieldable means, said last mentioned means operative to reduce the resistance ofiered by said yieldable means as the discharge pressure increases, means for subjecting said pressure responsive means continuously to compressor discharge pressure, fluid pressure operated means acting in a direction at right angles to the direction of operation of said pressure responsive means for actuating said controlling means in a direction to reduce the supply of operating fluid, and controlling means for said fluid pressure operated means controlled by said pressure responsive means.

15. A regulating mechanism for an engine driven compressor having fluid actuated unloading means, comprising, in combination, a throttle valve for controlling supply of operating fluid to the engine, means including a speed governor for urging said throttle valve toward its closed position, means for yieldably resisting the action or" said speed governor, pressure responsive means for varying the resistance offered by said yieldable means, means for subjecting said last mentioned means continuously to compressor discharge pressure, a second throttle valve for controlling the supply of operating fluid to the engine, pressure responsive means operative on the supply of operating fluid thereto to move said second throttle valve to a position efiecting operation of the engine at an idling speed, and means including a valve member controlled by said first mentioned pressure responsive means for supplying pressure fluid to said second mentioned pres sure responsive means and said unloading means.

16. A regulating mechanism for an engine driven compressor having fluid actuated unloading means, comprising, in combination, a throttle valve for controlling supply of operating fluid to the engine, means including a speed governor for urging said throttle valve toward its closed position, a plurality of springs for yieldably resisting the action of said speed governor, pressure responsive means for varying the resistance oifered by one of said springs, means for subjecting said last mentioned means continuously to compressor discharge pressure, a second throttle valve for controlling the supply of operating fluid to the engine, pressure responsive means operative on the supply of operating fluid thereto to move said second throttle valve to a position efiecting operation of the engine at an idling speed, and means including a valve member controlled by said first mentioned pressure responsive means for supplying pressure fluid to said second mentioned pressure responsive means and said unloading means.

17. A regulating mechanism for an engine driven compressor having fluid actuated unloading means, comprising, in combination, a throttle valve for controlling supply of operating fluid to the engine, means including a speed governor for urging said throttle valve toward its closed position, means for yieldably resisting the action of said speed governor including a lever, a spring acting between said lever and a fixed point, a second lever and a spring acting between said second lever and said first mentioned lever, pressure responsive means for varying the resistance offered by said second mentioned spring, means for subjecting said last mentioned means continuously to compressor discharge pressure, a second throttle valve for controlling the supply of operating fluid to the engine, pressure responsive means operative on the supply of operating fluid thereto to move said second throttle valve toira apositionrefiecting. soperation; ofxthe engine.

actinggbetween saidjleicer. and .f.a;..fixed pointy. a

second .ilever gand:: a ;snring; acting :betvveenesaid second lever and said..firsti.;mentione.d ;.1ever,;.a prin n :bctween,;said second .mentioned levenand a .flxed point, pressure. responsive means fonvarying the resistanceofferedby saidsecond mentioned spring, means .ior ,subjecting aidlast mentioned means continuously to compressor dis-; charge; pressure, aysecond throttle valve for. con-J trolling the supply 1 of zoperat-ing fluid'to the .en:-.

gine, pressure responsive meansoperative onv the supply.;of operating fluidythereto to;move said second-throttle valve to a-position 'effectingopere ation-of, the engine at an idlingspeed-and means. including-a valve member; controlled by said first mentioned pressure responsive :means :for-isupe plying pressure .fluid 1 tog-said. second. mentioned pressure .,responsive me ans and said unloading means..-

19., A regulating, mechanism for an; engine driven .compressor having fluid. actuated.v unloads ing means, comprising in combination, -a throttle valveifor controlling-supplyof operating fluideto the-engine, means including. a speed governor for urging saidthrottle valve towarditsyclosed 130.51"? tion, means for yieldably resisting the. actioniof saidspeed governor includinga lever,;.aspring acting between said lever and.a...flxed:;point, a second lever and a spring acting betvveenesaid second lever and said first mentioned lever, pressure responsive means for varying the resistance offered by said .second mentioned spring, means for subjectingsaidlast mentioned means-.continuously to compressor discharge pressure, a second throttle valve for controlling the supply of operating fluid to the engine-,pressure responsivermeans operative on thessupply of operating fluid thereto to move ,saidsecondthrottle valve toga position effectingoperationof the engine, at an. .idling speed, and .means including .a valve member controlled by ,saidfirst: mentionedpressure responsive means and positioned forunseating,by said second mentioned lever for supplying pressure fluid to said second mentioned pressure responsive means and said unloading means.

20. A regulating mechanism for an engine driven compressor having fluid actuated unloading means, comprising, in combination, a throttle valve for controlling supply of operating fluid to the engine, means including a speed governor for urging said throttle valve toward its closed position, means for yieldably resisting the action of said speed governor, pressure responsive means for varying the resistance offered by said yieldable means, means for subjecting said last mentioned means continuously to compressor discharge pressure, a second throttle valve for controlling the supply of operating fluid to the engine, pressure responsive means operative on the supply of operating fluid thereto to move said second throttle valve to a position effecting oper- 18 ation of: the-.gengine atanidling speed; and means. controlled :by said. first; mentioned pressure ire-5 sponsive :means.-,-for.asupplyin pr ssure 'fluidi to and venting pressure fluid from said second men,-

. tioned pressure responsive ,meansandsaid unloading means,..said;means-for supplyingrpressure fluid-rte andventingjpressure' fluid from-said second mentioned pressureresponsive :means. and saidaunloadinggnieans including a vent controlling valve randa1 pressurenfluid supply ;.va1ve movable by said vent controlling valve,

21. A regulating mechanism -.for; an engine drivenrcompressor having fluid actuated unloade ing means,- comprisingin -.combination, a;,throttle valve for controllingsuppl .ofoperating ,fluidflto. the,-engine,-s;means;including a speedgovernorfor urging-said throttle valve -.toward its closedpt si tion,; meanszrforqyieldably resisting the action-of said speeds. governor, :ptessure responsive :means foryarying the resistance offered ,by saidyyieldeg able, means, means for-subjecting said last mene tionedemeans continuously to compressor dis-.. charge pressure, a second throttle 1 valve; for. controlling"; the supply of operating fluid. to lthe en ine. pressure responsivemeans operative'-;on the -,-supply -of operating -fluid ,thereto. tomove said second throttle valve to a position-effecting operation of the engine at-anidling speed, .and means controlled by said-first mentionedpressure responsive ,means -for supplying pressure fluid to and ventingipressure fluidfrom saidrsecond men: tioned pressure responsive means and said .-,un-. loading means-said means.for-supplying-pressnre fluid .to .andventin pressure fluid from .said- SEQ-I 0nd mentioned vpressure responsive means :and said unloading. means including, a vent controlling valve and. a=pressurewfluid supply valveimovable by saidvent controllingyalve, said pressure re sponsive meansincluding a ,leverpivotable-to vary theresistance oftered by said yieldable means .and when. substantially in; one. limiting position thereof engageable with-said vent conetrolling valve to actuatethe latten;

22;, A,, regulating-,mechanism for" an engine driven, compressor havin -fluid :actuated unload-.- ing ;me.anssand'fuel regulating means for the engine, comprising, incombination, a control member v means operatively connecting said con trol amember to the fuel;- regulating means-;.for the engine, aqpressure responsive device connected :to ;said controlrmember and operativerby pressure fluid supplied thereto for actuatingsaid control member; toefiect a reduction in fuel sup:-

ply to "the engine, 7 means: for continuously supplying fluid discharged by the compressor tosaid pressure responsive device,- and-valve means .controlled I by ,i said, pressure fireSpQnSiVB device. for controllingqthe flow;- of; fluidwelative tosaidfluid actuated compressor unloading means to effect compressor unloading and loading.

23. A regulating mechanism for an engine driven compressor having fluid actuated unloading means and fuel regulating means for the engine, comprising, in combination, a control member, means operatively connecting said control member to the fuel regulating means for the engine, a pressure responsive device connected to i said control member and operative by pressure to the unloading means and operating in such position"'to prevent further movement of said control member by said pressure responsive device.

' 24. A regulating mechanism for an engine driven compressor having fluid actuated unloading means and fuel regulating means for the engine, comprising, in combination, a control member, means operatively connecting said control member to the fuel regulating means for the engine, a pressure responsive device operatively connected to said control member and operative by pressure fluid supplied thereto for actuating said control member to effect a reduction in fuel supply to the engine, means for supplying fluid discharged by the compressor to said pressure responsive device, unloading means controlling means including a valve member movable by said pressure responsive device to a position permitting fluid discharged by the compressor to flow to the unloading means, means for subjecting said valve member to a pressure in a direction opposing its movementby said pressure responsive device, and means for causing said valve member to be subjected to a lesser net pressure in such direction after movement by said pressure responsive device.

25. A regulating mechanism for an engine driven compressor having fluid actuated unloading means and fuel regulating means for the engine, comprising, in combination, a control member, means operatively connecting said control member to the fuel regulating means for the engine, a pressure responsive device operatively connected to said control member and operative by pressure fluid supplied thereto for actuating said control member to effect a reduction in fuel supply to the engine, means for supplying fluid discharged by the compressor to said pressure responsive device, pressure responsive means operative on the supply of pressure fluid thereto for effecting a slowing down of the engine to an idling speed, mean for effecting compressor unloading and a further slowing down of the engine including a valve member movable by said pressure responsive device to a position for supplying fluid discharged by the compressor to the unloading means and to said pressure responsive means, means for subjecting said valve member to a pressure in a direction opposing its movement by said pressure responsive device, and means for causing said valve member to be subjected to a lesser net pressure in said direction after movement by said pressure responsive device.

26. A regulating mechanism for an engine driven compressor having fluid actuated unloading means and fuel regulating means for the engine, comprising, in combination, a control member, means operatively connecting said control member to a fuel regulating means for the engine, a pressure responsive device operatively connected to said control member and operative by pressure fluid supplied thereto for actuating said control member to effect a reduction in fuel supply to the engine, means for supplying fluid discharged by the compressor to said pressure responsive device, means for conducting fluid to and from the compressor unloading means, and a pair of valve members for controlling the connection of said fluid conducting means to atmosphere and to the compressor discharge, one of said valve members movable by said pressure responsive device and operating to position the other of said valve members.

27. A regulating mechanism for an engine driven compressor having fluid actuated un1oading means and fuel regulating means for the engine, comprising, in combination, a control member, means operatively connecting said control member to a fuel regulating means for the engine, a pressure responsive device operatively connected to said control member and operative by pressure fluid supplied thereto for actuating said control member to effect a reduction in fuel supply to the engine, means for supplying fluid discharged by the compressor to said pressure responsive device, means for conducting fluid to and from the compressor unloading means, and a pair of valve members for controlling the connection of said fluid conducting means to atmosphere and to the compressor discharge, one of said valve members movable by said pressure responsive device and operating to position the other of said valve members, means for subjecting said valve members to pressures in a direction opposing their movement by said pressure responsive device and means for reducing the net cumulative pressure acting on said valve members in said direction after movement thereof by said pressure responsive device.

WIN W. PAGET.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,394,819 Ferguson Oct. 25, 1921 1,550,875 Carpenter Aug. 25, 1925 1,550,876 Carpenter Aug. 25, 1925 1,550,964 Jones Aug. 25, 1925 2,171,285 Baker Aug. 29, 1939 2,178,660 Carpenter Nov. 7, 1939 2,212,631 Baker Aug. 27, 1940