US2620628A - Fluid pressure operated motor - Google Patents

Description

Patented Dec. 9, 1952 VUINII'TIED i 'STATE' S AT ENT oli-#Fica .FLUID :PRESSURE oPERA'rEnMo'roR WilliamA:Ray,-North-Hollywood, Califgassignor to General l(Jon-trols Co., Glendale, Califg-a'corsporationQof :California reApplication July, 1951, .Serial No.2.35.,.467

(on ca -52) ceding Obj ect which, employs an elastic iiuidsuch es compressed air.' .both .forits operation. and' for its control.

Another .cbjeotis '.to `proyidea pneumatically operated andl controlled motorwhose actuating memberishydraulically operated and locked in position.

For full understanding of' the invention, and further ,appreciation of its A'objects Aand advantages, referenceis'` to 'be iha'd ,to jthe following .j detailed description and accompanying drawing. andtothe appended claims.

'Ifhe single 'gureof the drawing is a sectional view of a'uid pressure motor embodying 4the inventorl; the figure including a diagrammatic showing of a conventionaVvalve positione1""for controlling the motor.

The motor structure shown in the drawing comprisesa disk-like basev ll having ,a vplurality of'legs l2 for attaching the structureyvtoa device toQbe operated, such as a fluid control valve. Mounted on top of the base is a main pressure.- motor Ai3 which comprises a cylinder Iasealingly secured jto thebase, and a cooperating plunger Irhaving a stem i6 sealingly extending through an opening in the base for connection to the stem ofthe device to be operated. The space around the motor I3 is iconi-lnedby a tubular housing l1, secured t o the `periphery of base ll, to provide a reservoir ljfor'hydraulic uld for operation 'of this motor;y the surface of 'this' fluid beingindicated-by'the'legend OilleVeL On'top of the motor cylinder M, and secured thereto by vits anged'base 19, 'is a pump structure 20having a'bore '2 1 Vfor a reciprocable piston 22. jIn `the side of thepump structure isa slot 23through-which liquid from the reservoir .I8 enters the' bore V2lwhen the piston 22 is lin* the position shown and, when vthepiston is moved downwardly (by/means tobe described) vforced through a `passage 24" vair-the bottom of" the bore structure ris a huid-pressure reciprocating jm chamber-38 the space below the 35 packing member 44.

into a `chamber325 and' thence-to Y'the spaelpr pressure chamberZS belcwthe plunger: L5 orfthe main pressure-,motor :bywvay of Zaspipeiz'l inteliconnecting these .chambers; acheck lvalve2 8, bia-sed by aspringi into engagementwithja seat formed'at the, bottom ofpassage'd, preuent.- ing return `of :the v,liquid When'the piston f2? 'isretracted.

.Pumoins 0f liquid .into the space' .126' belowtbe plunger .Causes .the .sam-eet@ riseaeainsttherorce 0fy a lserine 'zcompressodi between ihopliniger alldthelbase |.9' Of 511613111913 .Strlllll th'ell aboverihe v,runser being infree communication withv the reservoirrbyrway of an Vopening". 31 in the .upper jpart of 'cylinder 1 4. jgAj-projection-32 of the'mctor stemi limits 'upwardlmovemerlt of the plunger.

`v'lhe chamber' 2e vbelow' the purnpfis 'also gonnecredby a bentpipeiio anoponiog 'leadins to 'the piston 100.17621 eiaponibsrondrthe renee of v pumping movementof -piston'I 22, so that when (in a manner to-bedescribed) vthe-pistonisjraised slightly above :its position vasshown 1in thejdrawing fluid can escape fromithe'rnainemotorcham- 25, pipe l3S, opening-3d, 'bore-2l 'and s101123.; :the plungerlfalling under fthe force ofgspringep.

On 'the .dished top Lportion 35 of ':iheipunip tor, or pulsator, 5B which comprises ia, v:flexible phragm lSle'clarnped at-its Vinarginibetweenthe dished portion'ii and aninverted dished-member 31 which defines with the 4diaplrragrrr apressure diaphragm-beingvented to atmosphere-bilanopening 91 "'Ihe central part or Vdiapliragmfi -is' clarnped tolithe upper end of piston 22 by a nume-threaddlon the top 4extension-tl of 4kthe -pistonffs'tiiien-ing n platesiar being .provided'oneither side o'f the 'iiajphragin.

The vdiapl'iragin 'and' piston assembly-is biased upwardly by a-springs-B encirclingiythepiston and bearing at Vits `bottom -on a-conventional above the diaphragrnis Iat atmospheric--pressure thetop yofpiston-extension ll-l isdn engagement with the 'member-3i undereithe force-offspring 43 ;-it beingvassumed that with the lparts jinv'kthe positions sho-wn .in the-drawingthe pressn'rerin chamber A'-33 is slightly -in 1excessofw atmospheric, aswillvbe described.

For supplying pressure -iiuid to thechamher I of the -reciprocatir-1glmotor,A Iand for'ventingi'it,

.there is a--Kpair of alignedLvalve-jets *45 -^and^-46 projecting -into the-chamber; `the lowerljete When the chamber being secured in openings through the dished members 31 and 35 and communicating with a threaded recess 41 in the latter, the other jet 46 being threaded in an opening through the top wall of member 31. The jet 46 leads directly to atmosphere, but in the event that a uid such as high-pressure fuel-gas is employed for the reciprocating motor, the recess 48 with which jet 46 communicates may be threaded for the connection of means for utilizing the gas.

Between the jets 45 and 46, and alternately cooperable with the individual jets, is a dualended closure 49 carried by an arm 50 whose left-hand end is fulcrumed in the root of a notch provided in the right-hand end of a lever 52 which is pivoted on a pin 53 projecting from a bracket 54 attached to the member 31. As shown in the drawing, the right-hand end of arm 50 is urged in upward direction by a spring 55 tensioned between the arm and pivot pin 53 so that closure 49 is held in engagement with the upper jet 46; the closure being so mounted on arm 55 that it is free to conform to the plane of the tips of the jets. This upward tension on arm 58 is due to the fact that the left-hand edge of the arm (fulcrumed in notch 5l) is slightly below the line of force of spring 55. The rounded lefthand end of lever 52 is supported by a grooved collar 56 threaded on the piston-extension 4l (and locked in adjusted position, as by a through pin, not shown) so that when the piston moves downwardly (as will be described) the lever 52 is rocked counterclockwise. When the position of the lever then becomes such that the root of notch 5I is just above the line of force of spring 55 (the bottom of piston 22 being just above the level indicated at A) the arm 50 is snapped to its alternate position with closure 49 in engagement with the lower jet 45. The lever 52 consists of two like portions joined together at the top by a bridge 51 and spaced apart sB-that the left-hand ends of the lever are in the groove of collar 56 and at opposite sides thereof; the arm 56 being bifurcated s0 that it has two left-hand ends which rest in the notches in the right-hand side portions of lever 52.

At the right of the motor structure, and generally indicated by the numeral 60, are means for supplying fluid, such as compressed air, to the reciprocating motor 58, and for regulating the supply of fluid in response to variations of a condition, such as temperature or pressure, which variations require corresponding variation of the position of the valve or other device connected to the main-motor stem I6. The means 60 are of conventional design and are therefore shown diagrammatically.

The numeral 6l indicates a stationary member to opposite sides of which one end of a bellows 62 and of another bellows 63 are attached; the bellows carrying at their other ends heads 64 and 65 which are rigidly interconnected by a rod 66 extending freely through an opening 81 in the member 6|.

The space around the bellows 63 and its head 65 is enclosed by a housing 61 to provide a pressure chamber 68 which is connected by a pipe 69 to a source of pressure iiuid (conveniently, compressed air) indicated by the legend. Branching from the pipe 69 is a jet 10 with which a movable instrument arm 1l cooperates. A fixed restriction 12 is provided in pipe 69 ahead ofjet 10, so that when the arm 1I is rocked away from the jet the iiuid passing the restriction can readily escape through the jet and the pressure '4 applied to chamber 68 is substantially atmospheric; the pressure in the chamber increasing as the arm 1l is moved toward the jet and becoming equal to that of the source when the jet is closed by the arm. The arm 1I corresponds to the movable element of a condition-responsive instrument such as a thermostat.

The fluid pressure in chamber 63 acts on the bellows head 65 to move it, and the interconnected head 64, toward the left; such movement, however, being opposed by the force of a spring 13 compressed between head 64 and (through a disk 14) the tip 15 of a bell-crank lever 16 whose lower arm is connected by a, link 11 to the mainmotor stem I6.

The stationary member 6I has a vertical passage 18 which is connected by a pipe 19 to a source, indicated by the legend, of operating pressure iiuid which may be high-pressure air; the passage 18 having at its inner end a branch opening 80 with which a conical closure 8l cooperates. This closure is connected by a stem 82 to a similar closure 83 which cooperates with a vent opening 84 through the bellows head 64, the closure assembly being biased toward the right by a spring 85. The arrangement is such that both of the closures 8| and 83 are seated when the opposing forces acting inwardly on the bellows heads 64 and 65 are balanced. When, due to the unbalance of these forces, the bellows assembly is moved toward the left closure 8| is unseated; closure 83 being unseated when the assembly is moved toward the right. In the top of member 6l is a, vertical passage 86 which joins the transverse opening 81 and is thus in communication with the interior of bellows 62 and 63; passage 86 being connected at its outer end to a pipe 83 which extends to the inlet fitting 41 of the reciprocating motor 58.

From the foregoing it is clear that with rise of instrument pressure in chamber 68 operating pressure-huid is supplied to the reciprocating motor; and with fall of instrument pressure the inlet of the reciprocating motoris connected to atmosphere. It is to be observed that operating pressure-fluid within the bellows acts equally and oppositely on the heads 64 and 65 and therefore does not tend to alter the position of the bellows assembly.

As shown in the drawing the parts are in the positions taken when the instrument arm 1| is in a low-pressure producing position; the pressure in diaphragm chamber 38 is correspondingly low (but not atmospheric) the piston 22 is at the top of its pumping stroke (position B); and the main pressure-motor stem I6 is in its lowermost position.

Assuming now that the instrument arm moves closer to jet 10: the resultant rise of pressure in chamber 68 eiects movement of the bellows assembly toward the left so that closure 8l is unseated Vand operating pressure-duid passes to the reciprocating motor, forcing the diaphragm and piston 22 downwardly. Just before the piston reaches the end of its downward or pumping stroke (position A) arm 50 is snapped to its alternate position so that the closure 49 is moved out of engagement with jet 46 and into engagement with jet 45. The resultant venting of chamber 38 permits the diaphragm and piston to rise rapidly under the force of spring 43. But just before the piston reaches its B position the position of arm 56 and closure 48 is reversed so that pressure above the diaphragm again rises and the pumping stroke is repeated; each downwardgmovementgofthe pistongforcing oilgfrom the reservoirto the .chamber 26 vbelow the plunger |15 -s o `that theisame rises. `The accompanying ,up- Walid movement. of stem |16 effectsclockwise rotation of bell-.crank i6 so that the force of spring I3-is increased andathe bellows assembly moves toward the right to eifect reseating of'closure B I, s o-that-:operation `of `the `reciprocating motor ceases ythepressure of the 'fluid trapped in chamber 38 vmaintainingthe ,diaphragm and piston stationary at some vposition within the pumping range, such as thegpositi-onshown in the ldrawmg.

If the instrument pressure in chamber G81-continuesnto rise 'the closure 3l will be again unseatediandfthe pumping operation repeated until the'main-motor stemrises toa position `wherein the. ;force ;of spring 13 vhas vbeen Vincreased `suiiiciently to balance the higher opposing fluid pressurein chamber (58;` itbeing assumed that the pressure ofthe operating lfluid vsupplied Sto the reciprocating motor is high enough that the increaseof forceof the bias springtl as theplunger rises is vanegligible factorinthe operation of lthe System.

Ifthepinstrument arm Vnow moves farther from .let HL- the resultant reduction of pressure in chamber 6 8 permits the bellows assembly to move liQWald the right under the force of spring 73, andthe vent closure 83 is unseated. When this occurs .the diaphragm chamber 38 is Vented through jet.45,.pipe 83, the interior of bellows E2, 6 3, and opening 8 4; it beingassumed that jet45 was open, sinceitnat jet is closed onlyduring the brief. lreturn stroke of the .piston under the ,force Aof spring 43.

This venting of chamber 38 by the controlap.- paratus 68 f permits the diaphragm .and piston ato risetofull extent under .the `force of spring 43; thepiston-extension 4l .then being in engagement with member 3.1 and the-bottom of the piston in itsC position (closure 39 remaining in engagement with jet 46). The liquid under pressure in chamber 26 below the 4plunger now escapes ythrough the. opening 3d, which opening is closed bythe Vlower portion of the pistonr 22 except when thepressure in chamber 38 is at, or only slightly above, atmospheric. The resultant f all of Vplunger l 5 effects reduction ofthe force Yof spring 13 to compensate for the reduction/of pressurein chamber 68 (which caused the Aoperation just described) and the bellows assembly returns to its balanced position wherein both of the closures 83 and 8l are seated.

'summarizing the foregoing description of operation: with rise of instrument pressure, pressure fluid issupplied to the reciprocating motor 58 so that the pump piston 22 is reciprocated to force liquid to the space below plunger l5, causing the same to rise until the resultant increase of force of spring 'I3 balances the instrument pressure, whereupon operation of the pump ceases due to seating of closure 8|. With fall of instrument pressure, the reciprocating motor is vented so that the piston 22 rises above its pumping range to permit venting, through the opening 34 then uncovered by the piston, of liquid from the main pressure-motor so that plunger l5 falls until it reaches a position wherein the opposing forces acting on bellows 62, 63 are again balanced and the vent-closure 83 seated. In this manner the valve, or other device, connected to stem I6 is operated to positions corresponding to those of the instrument arm 1l, and is locked securely in :those Vpositions due lrto the trapped liquidr which fills thespace below the plunger.

In theevent of leakage from the Vmain-:motor chamber 26 or from the diaphragm chamber38, the resultant fall of stem I6 effects unseatingof closure 3| so that additional pressure luidzis supplied to the reciprocating motorand liquid Vis pumped in an Vamount sufcient to return the stem I6 to its Yprevious position (assuminguthat the instrument pressure hasremained'constanil). It is to be observed that the opening 34 ferventing the hydraulic-fluid is located close to the top of theV pumping range of the piston so that the vent is uncovered by the piston uponsmall reduction of pressure above the diaphragmp-the system. therefore responding quickly tothe slightest opening of vent closure 83. rIhe follow-up spring vi3 is preferably arranged so that its force becomes suilcient tobalance the maximum-available instrument rpressure just vbefore the-mainmotor stem I6 reaches its limit of upwardmovement.

The rate of operation of `.the 'reciprocating motor and pump is generallynproportional.to the magnitude of increase of instrument pressure which initiated that operation, since with a large increase of instrument pressure the closure 3l will be withdrawn far from its seat so that the pressure drop thereacross will be vsmall andthe fluid will be supplied to the diaphragmlchamber at correspondingly high pressure.

The specific embodiment of -my invention vherein shown and described is obviously susceptible of modification without departing from the spirit of the invention, and I intenditherefore to be limited only by the scope of the appended claims.

I claim as my invention:

1. In combination: a main lpressure-motor comprising a movable member adapted to beconnected to a device to be positioned, and biased -to one position; a pump for forcing fluid to said motor and fluidly connected to the motor so that operation of the pump effects gradual movement of said member toward an opposite position against the force of said bias; a duid-pressure reciprocating motor for operating said pump and adapted to be connected to a controlled supply of pressure fluid, said reciprocating motor comprising a movable wall operatively connected to said pump, and valve means actuated by movements of said wall rwhen the same is .adjacent opposite ends of its range of movement for so applying said pressure iluid to the wall that, when the pressure of ,that'uid is in excess of a predetermined minimum amount, the wail is automatically reciprocated in said range to opcrate the pump; and ymeans responsive to the pressure of the fluid supplied to said reciprocating motor and effective, when that pressure falls below said minimum amount, to vent said main pressure-motor so that said member can move toward its biased position.

2. The combination defined in claim 1, and wherein said means for venting said main pressure-motor comprises valve means actuated by movement of said reciprocating-motor wall.

3. The combination defined in claim 1, and wherein said reciprocating-motor wall is biased toward one position, and. said means for venting said main pressure-motorcomprises valve means actuated by movement of said wall to said one position.

4. The combination defined in claim 1, and wherein said pump comprises a piston, connected to said reciprocating-motor wall, and a cooperating cylinder; and wherein the vent for said main pressure-motor is formed by an opening in the Wall of said cylinder positioned so that it is closed by the piston in its pumping stroke.

5. In combination: a main pressure-motor comprising a. movable member adapted to be connected to a device to be positioned, and biased to one position; a pump for forcing fluid to said motor and fluidly connected to the motor so that operation of the pump effects gradual movement of said member toward an opposite position against the force of said bias; a duid-pressure reciprocating motor for operating said pump and adapted to be connected to a controlled supply of pressure fluid, said reciprocating motor comprising means dening a pressure chamber having a movable Wall biased toward one position and operatively connected to said pump, and valve means actuated by movements of said wall when the same is adjacent opposite ends of its range of movement for alternately applying said pressure fluid to the Wall and venting said chamber so that, when the pressure of that fluid is in excess of a predetermined minimum amount, the wall is automatically reciprocated in said range to operate the pump; and means responsive to the pressure of the fluid supplied to said reciproeating motor and effective, when that pressure falls below said minimum amount, to vent said main pressure-motor so that said member can move toward its biased position.

6. The combination deiined in claim 5, and wherein said means for venting said main pressure-motor comprises valve means actuated by movement of said reciprocating-motor wall to its biased position.

7. The combination dened in claim 5, and wherein said pump comprises a piston, connected to said reciprocating-motor wall, and a cooperating cylinder; and wherein the vent for said main pressure-motor is formed by an opening in the Wall of said cylinder positioned so that it is closed by the piston in its pumping stroke.

8. In combination: a main pressure-motor comprising a movable member adapted to be connected to a device to be positioned, and biased to one position; a pump for forcing fluid to said motor and fluidly connected to the motor so that operation of the pump effects gradual movement of said member toward an opposite position against the force of said bias, said pump comprising a reciprocable piston and means forming a cylinder therefor; a fluid-pressure reciprocating motor for operating said pump and adapted to be connected to a controlled supply of pressure fluid, said reciprocating motor comprising means dening a pressure chamber having a movable Wall biased toward one position and operatively connected to said piston, as Well :as valve means actuated by movements of said Wall when the same is adjacent opposite ends of its range of movement for alternately applying said pressure fluid to the Wall and venting said chamber so that, when the pressure of that fluid is in excess of a predetermined minimum amount, the Wall is automatically reciprocated in said range to operatethe pump; and means for venting said main pressure-motor so that said member can move toward its biased position, said last-named means comprising additional valve means actuated by said Wall when, in response to reduction of pressure in said chamber below said minimum amount, the Wall moves under the force of its bias to a position beyond its range of pumping movement.

9. The combination dened in claim 8, wherein the Vent for said main pressure-motor is formed by an opening in the Wall of said cylinder positioned so that it is closed by the piston in its pumping stroke.

l0. In combination: a main pressure-motor comprising a movable member adapted to be connected to a device to be positioned, and biased to one position; a pump for forcing liquid from a source thereof to said motor and fluidly connected to the motor so that operation of the pump effects gradual movement of said member toward an opposite position against the force of said bias, said pump comprising a reciprocal piston and means forming a cylinder therefor, said cylinder having in its side-wall an opening for entrance of liquid from said source when the piston is retracted and closed by the piston 1n its pumping stroue; a :luid-pressure reciprocating motor for operating said pump and adapted to be connected to a controlled supply of gaseous pressure-huid, said reciprocating motor comprising means dening a pressure chamber having a movable wall biased toward one position and operatively connected to said piston, and valve means actuated by movements of said wall when the same is adjacent opposite ends of its range of movement for alternately applying said pressure fluid to the wall and venting said chamber so that, when the pressure of that fluid is in excess of a predetermined minimum amount, the Wall is automatically reciprocated in said range to operate the pump; and means for venting liquid from said main pressure-motor so that said member can move toward its biased position, said last-named means comprising an additional opening in said cylinder sidewall positioned so that it is normally closed by said piston and is uncovered by the piston only when, in response to reduction of pressure in said chamber below said minimum amount, said movable Wall is moved under the force of its bias to a position beyond its range of pumping movement.

WILLIAM A. RAY.

No references cited.

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