US2826149A - Booster pump - Google Patents

Booster pump Download PDF

Info

Publication number
US2826149A
US2826149A US496164A US49616455A US2826149A US 2826149 A US2826149 A US 2826149A US 496164 A US496164 A US 496164A US 49616455 A US49616455 A US 49616455A US 2826149 A US2826149 A US 2826149A
Authority
US
United States
Prior art keywords
fluid
line
pressure
pumping
movable
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US496164A
Inventor
Clifford C Wrigley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motors Liquidation Co
Original Assignee
Motors Liquidation Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Motors Liquidation Co filed Critical Motors Liquidation Co
Priority to US496164A priority Critical patent/US2826149A/en
Application granted granted Critical
Publication of US2826149A publication Critical patent/US2826149A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01LCYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L25/00Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means
    • F01L25/02Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means
    • F01L25/04Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means by working-fluid of machine or engine, e.g. free-piston machine
    • F01L25/06Arrangements with main and auxiliary valves, at least one of them being fluid-driven
    • F01L25/066Arrangements with main and auxiliary valves, at least one of them being fluid-driven piston or piston-rod being used as auxiliary valve
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B9/00Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/08Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
    • F04B9/10Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid
    • F04B9/109Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers
    • F04B9/111Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers with two mechanically connected pumping members
    • F04B9/113Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being liquid having plural pumping chambers with two mechanically connected pumping members reciprocating movement of the pumping members being obtained by a double-acting liquid motor

Description

March 11, 1958 c. c. WRIGLEY 2,326,149
BOOSTER PUMP Filed March 23, 1955 3 Sheets-Sheet 1 .INVENTOR C. C. WRIGLEY BOOSTER PUMP March 11, 1958 Filed March 23. 1955 5 Sheets-Sheet 2 INVENTOR g/aim Wily/5y r 2,826,149 BOOSTERrPUMP Application March '23, 1955, Serial No. 496,164 7 Claims. (Cl. 1 03-51) This invention relates to booster pumps and more particularly concerns a pump of this type which is controlled by fluid pressure.
it is frequently desirable or necessary in hydraulic circuits, for example, to increase the available line pressure for the operation of one or more actuators, either not susceptible of operation at line pressure or giving better performance at a higher pressure. Thus, in an auto motive vehicle equipped with a hydraulic transmission, it is possible to draw'oil under substantial pressure from the transmission for operation of various accessories through suitable jacks, power cylinders, or the like. However, the pressure so derived is not generally adequate with respect to certain accessories as, for example, a hydraulic power steering system of the type comprising a closed-center valve and an accumulator from which the steering actuator or assist-or draws.
The invention herein answer-s fully to the indicated specific need and booster pumps according therewith are adapted for many other applications too numerous to mention.
Several of the more important objects of the invention are: to provide a booster pump capable of control by fluid pressure; to provide such a pump capable of control by fluid at inlet pressure; to provide a pump of simple design and low cost, which will be virtually infallible in operation.
Other objects and features of the invention will be apparent from the following description of a preferred embodiment thereof which will proceed with reference to the accompanying drawings in which:
Figure l is a schematic'representation of the particular P p;
Figure 2 is a plan showing the pump with the top cover removed;
Figure 3 is parts;
Figure 4 schematically illustrates a modified construction; and
Figure 5 is a performance curve on the pump of Figures 1-3.
Referring first to Figure l, the principal working parts of the pump are a motor piston having pumping pistons 12 connected thereto or integral therewith and a control valve spool 14-. This spool or plunger comprises lands 16, 18, 20, and 22 and an enlarged portion 24 of substantially the same diameter as the lands functional with relation to the springloa-ded balls 26. These balls and the associated springs afford a detent action for a purpose which will be shortly explained.
Spool 14 is reciprocal within a valve body formed to provide annular channels Fall, 32, 34, 36, 38, and 40. Also there is provided central exhaust channels 42 opening to a common exhaust line 44-.
Fluid at line pressure, 90425 p. s. i., for example, enters the pump via line 46. This line is common to lines 48 and 50, which connect, respectively, with the annular channels 32 and 38. Branching from line 4% a longitudinal section showing the principal tee l atent t) is aline 52 opening to the chamber 54, in which'the lefthand pumping piston 12 reciprocates, and connecting with the highpressure or discharge line'56. Similarly, line 58, branching from line 50 opens-to the chamber-60, in which the right-hand pumping piston 12 reciprooates, and terminates in the high pressure line 56. Each of lines 52 and 58 has thereina pair ofcheck valves 62, '64 and 6d, 68 respectively.
In addition ito-the lines or conduits just-described,the system includes lines or passageways 70 and 72 extending from the annular channels 34 and 36, respectivelyytothe chamber 74 in which the motor piston 10 reciprocates, line '70 serving the left-hand portion of such 'chamb'ertas delineated by-the piston), line 72 the right-hand portion thereof.
With the control valve spool 14 in the position shown, fluid at line pressure is entering the right-hand portion-of the chamber 74, moving the piston 10 leftward, through line 50, annular channels 38, 36, and line 72. Simultaneously, fluid at exhaust pressure is being discharged from the lefthand pontion of the chamber 74 via line 7 0, annular channels 34 and 42, and the common exhaust line 44. As the piston 10 completes its leftward stroke, line 76, which includes an orifice 78, and which connects with annular channel 40 at the right-hand end of the spool 14, becomes open to the pumping chamber 60. On this occurrence, fluid from such chamber enters the annular channel 40, there to exert a leftward force on the valve spool 14 to shift the same in that direction to an extent such that the balls 26 over-ride the center of the enlarged portion 24 of the valve spool. Once this overriding has taken place, the further leftward movement of the spool is effected by expansion of the springs backing up the balls.
A central bore 80, extending through the valve spool, connects with radial passageways 82 in the spool so that fluid is permitted to bleed from the annular channel or chamber 40 to exhaust.
As the valve spool 14 reaches its leftward position corresponding to the maximum leftward displacement of piston 10, it closes off the exhaust passageway from the left side of the chamber 74 so that the piston is locked in position. On further progress of the valve spool to the left, the feed to the right-hand portion of chamber 74 becomes closed off, with opening of the left-hand portion of the chamber to line pressure. Piston 10, however, does not yet begin its rightward stroke, because the righthand exhaust passageway is not yet open. On final leftward movement of the valve spool, with the force required for such movement being supplied by the detent means, annular channel 36 becomes open to the righthand exhaust channel 42 land the piston 10 accordingly moves rightward.
With completion of the rightward stroke of the piston, the valve action is reversed, the rightward movement of the spool being initiated by the fluid pressure developing in annular channel or chamber 30, this fluid being derived from the pumping chamber 54 through a line 84 having an orifice 86 therein and representing the counterpart of the line 76.
it should be evident that the reciprocation of the pistons 12 provides a pumping action resulting in the drawing of inlet fluid from lines 52 and 58 and the discharge of fluid into the common high pressure line 56. With the piston 10 in its position shown (Figure l), the right-hand pumping piston 12 is in the middle of its suction stroke, while the left-hand pump pistonis in the middle of its discharge stroke, a condition reflected by the ball check valves 64 and 66 both of which are shown off their seats.
In view of the foregoing, description is required in the case it is believed that little of Figures 2 and 3 assua e showing the actual pump construction and wherein the same numerals are employed as in Figure 1, the parts being reversed. It may be noted, however, that all of the moving parts are housed within a single block or body 38 of metal or other appropriate material, suitably bored and counterbored to provide the various passageways and chambers, Alternatively, the valve body may be cast to reduce the amount of boring necessary. The particular construction includes two cover plates 94 and 92 shown as bolted to the body $8.
In Figure 2, certain of the passageways and check valves are shown in broken lines as these would not actually appear in the true section.
Going now to Figure 4 illustrating a modified arrangement and wherein parts functionally similar or identical to parts shown in Figure 1 are denoted by like numerals, the numerals, however, being primed, it is to be noted that in this case the fluid at inlet pressure which initiates the reverse movement of the valve spool 14 is not derived from the lines 52 and 58 but from lines 94 and 96, respectively.
Line 94 opens to annular channel 32 which in turn is open to the inlet line 46. Similarly, line 96 connects with the annular channel 38' which in turn connects with the inlet line 46 via branch line 56). Transfer of inlet fluid from lines 94 to line 84', for example, occurs when the left-hand pumping piston 12' is in its position where the annular groove ltltl formed in the piston is in centered relation with respect to the lines 34 and 94, more accurately the orifice portions 86 and N2 of these lines.
With the parts in their relative positions as shown in Figure 4, the motor piston 10 is being moved to the left by inlet fluid entering the chamber '74 from line 72', line '7il being open to exhaust line 44. As the right-hand pumping piston 12' reaches a leftward position such that the corresponding annular groove 100 allows for fluid flow between the line 96 and the line 76 the valve spool 14' is shifted leftwardly as afore described to reverse the action, the initial movement of the spool being induced by the pressure of inlet fluid at 4d.
Further description of the modified construction represented by Figure 4 is believed unnecessary in view of the detailed description supplied above referring to Figure 1.
In the case of either construction illustrated, the pumping action will be fast when the high pressure discharge is being dissipated, as in the operation of an actuator, and when this pressure is relatively low. But as the high pressure approaches a certain maximum value, the pump will slow down and will maintain this maximum pressure with only enough movement to compensate for leakage of high pressure fluid. The curve of Figure 5 illustrates this characteristic of the pump. In such figure the discharge pressures are plotted as ordinates, the times, in seconds, required for the discharge of one quart of fluid (hydraulic transmission oil) at these pressures as abscissae. The figures were obtained from the operation of a pump conforming to Figures 13. The inlet pressure was 120 p. s. i., the exhaust pressure 15 p. s. i. This pump has a displacement of 0.33 cubic inches per cycle, equivalent to 153 cycles per quart discharged.
I claim:
1. A booster pump having fluid motor means actuable by the pressure of inlet fluid, pumping means operably connected to said fluid motor means, said pumping means being housed within a chamber connected to the source of inlet fluid, control means for said motor and pumping means including a housing confining a movable element, means governed by said pumping means to bring about initial movement of said movable element, and a detent device comprising yielo'a-ble means accommodated within said housin and means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element.
2. A booster pump having double-acting fluid motor means actuable by the pressure of inlet fluid, pumping means operably connected to said fluid motor means, said pumping means being housed within a chamber connected to the source of inlet fluid, control means for said motor and pumping means including a housing confining a movable element displaceable in two directions, means governed by said pumping means to bring about initial movement of said movable element in either direction, and a detent device comprising yieidable means accommodated within said housing and further comprising means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element in either direction.
3. A booster pump including a double-acting fluid motor having communication with a source of fluid pressure, means providing a pumping chamber at either end of said motor, said chambers being connected to a source of fluid, pumping means in each said chamber operably connected to said motor, control means for said motor and pumping means including a housing confining a movable element actuable by fluid pressure and displaceable in two directions, means providing a pair of chambers for receiving pressure fluid to bring about initial movement of said movable element in either direction, and a deter device comprising yieldable means accommodated within said housing and further comprising means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element in either direction.
4. A booster pump including a double-acting fluid motor actuable by the pressure of inlet fluid, means providing a pumping chamber at either end of said motor, said chambers being connected to a source of fluid, pumping means in each said chamber operably connected to said motor, control means for said motor and pumping means including a housing confining a movable element actuable by fluid pressure and displaceable in two directions, means providing a pair of chambers for receiving inlet fluid valved by said pumping means to bring about initial movement of said movable element in either direction, and a detent device comprising yieldable means accommodated within said housing and further comprising means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element in either direction.
5. A booster pump according to claim 4 where said detent device comprises a spring-loaded ball, the ball seating in annular grooves at the sides of a rounded landlike enlargement carried by said movable element.
6. A booster pump having fluid motor means actuable by the pressure of inlet fluid, pumping means operably connected to said fluid motor means, said pumping means being housed within a chamber connected to the source of inlet fluid, control means for said motor and pumping means including a housing confining a movable element, means providing a pair of chambers for receiving inlet fluid valved by said pumping means to bring about initial movement of said movable element, and a detent device comprising yieldable means accommodated within said housing and further comprising means loaded by said yieldable means having an operable connection with movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element.
7. A booster pump assembly including a fluid motor comprising a cylinder confining a double-acting piston, said cylinder having communication with a source of fluid pressure, means providing a pumping chamber at either end of said cylinder, each of said chambers having communication with said source and confining a plunger extending from a face of said piston, control means for said piston and plungers including a housing fixed to said cylinder and confining an axially movable element actuable by fluid pressure and displaceable in two directions, means providing a chamber at each end of said element for receiving fluid at inlet pressure valved by said plungers to bring about initial movement of said element in either direction, and a detent device comprising yieldable means accommodated Within said housing and further comprising means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element in either direction.
References Cited in the file of this patent UNITED STATES PATENTS
US496164A 1955-03-23 1955-03-23 Booster pump Expired - Lifetime US2826149A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US496164A US2826149A (en) 1955-03-23 1955-03-23 Booster pump

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US496164A US2826149A (en) 1955-03-23 1955-03-23 Booster pump

Publications (1)

Publication Number Publication Date
US2826149A true US2826149A (en) 1958-03-11

Family

ID=23971517

Family Applications (1)

Application Number Title Priority Date Filing Date
US496164A Expired - Lifetime US2826149A (en) 1955-03-23 1955-03-23 Booster pump

Country Status (1)

Country Link
US (1) US2826149A (en)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2991003A (en) * 1957-01-30 1961-07-04 Robert S Petersen Piston and compressor structure
US3016016A (en) * 1959-07-02 1962-01-09 Cincinnati Milling Machine Co Reciprocating pump
US3143075A (en) * 1961-06-12 1964-08-04 Halliburton Co Pump
DE1265586B (en) * 1958-04-23 1968-04-04 Crane Co Hydraulic device with double-acting differential piston
US3720484A (en) * 1970-03-04 1973-03-13 W Kirshsieper Hydraulic pressure transformer
FR2426166A1 (en) * 1978-05-18 1979-12-14 Control Concepts HYDRAULIC OSCILLATOR
FR2433660A1 (en) * 1978-07-29 1980-03-14 Kawasaki Heavy Ind Ltd HYDRAULIC CYLINDER, WITH INCREASED LOAD AT THE END OF STROKE
US4212597A (en) * 1978-03-22 1980-07-15 Salvador Gali Mallofre Pneumatic installations
US4314447A (en) * 1979-07-02 1982-02-09 Carrier Corporation Refrigerant motor
US4343595A (en) * 1976-12-20 1982-08-10 Wells David L Hydraulic power booster apparatus
WO1984002557A1 (en) * 1982-12-28 1984-07-05 Ethan A Silva A fluid intensifier
US4659294A (en) * 1985-01-09 1987-04-21 Eimco Secoma, Societe Anonyme Hydrualic pressure amplifier
US4659292A (en) * 1976-12-20 1987-04-21 Dennis J. Lawman Hydraulic power booster apparatus
US4767384A (en) * 1987-04-06 1988-08-30 Ford Motor Company Fluid pressure amplifier for an infinitely variable drive
US4780064A (en) * 1986-02-10 1988-10-25 Flow Industries, Inc. Pump assembly and its method of operation
EP0754271A1 (en) * 1994-03-03 1997-01-22 John M. Simmons Pneumatically shifted reciprocating pump
US5626467A (en) * 1996-04-04 1997-05-06 Teledyne Industries, Inc. Modular pump
USD380479S (en) * 1996-03-06 1997-07-01 Teledyne Industries, Inc. Modular pump
US20030099556A1 (en) * 2001-11-28 2003-05-29 Minibooster Hydraulics A/S Double-acting hydraulic pressure intensifier
US20040045430A1 (en) * 2002-09-09 2004-03-11 Vangstad Michael D. Reciprocating hydraulic motor utilizing a ramped valve yoke with a tripping spring
US6729860B1 (en) * 2000-01-24 2004-05-04 Daniel A. Holt Pneumatically driven liquified gas booster pump
US20150053075A1 (en) * 2013-08-20 2015-02-26 Vianney Rabhi Reversible hydraulic pressure converter employing tubular valves

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US157617A (en) * 1874-12-08 Improvement in hydraulic engines and rams
US305972A (en) * 1884-09-30 Axel sjogeen
US2053543A (en) * 1932-01-18 1936-09-08 Continental Motors Corp Fuel pumping system for engines
US2072325A (en) * 1931-11-14 1937-03-02 Augusta A Woodcock Duplex valve applied to a single cylinder
US2508298A (en) * 1948-04-16 1950-05-16 Oliver J Saari Fluid pressure intensifying device
US2631542A (en) * 1948-03-25 1953-03-17 British Industrial Plastics Hydraulic intensifier
US2708412A (en) * 1950-12-02 1955-05-17 Mueller Otto Booster for increasing delivered hydraulic pressure

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US157617A (en) * 1874-12-08 Improvement in hydraulic engines and rams
US305972A (en) * 1884-09-30 Axel sjogeen
US2072325A (en) * 1931-11-14 1937-03-02 Augusta A Woodcock Duplex valve applied to a single cylinder
US2053543A (en) * 1932-01-18 1936-09-08 Continental Motors Corp Fuel pumping system for engines
US2631542A (en) * 1948-03-25 1953-03-17 British Industrial Plastics Hydraulic intensifier
US2508298A (en) * 1948-04-16 1950-05-16 Oliver J Saari Fluid pressure intensifying device
US2708412A (en) * 1950-12-02 1955-05-17 Mueller Otto Booster for increasing delivered hydraulic pressure

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2991003A (en) * 1957-01-30 1961-07-04 Robert S Petersen Piston and compressor structure
DE1265586B (en) * 1958-04-23 1968-04-04 Crane Co Hydraulic device with double-acting differential piston
US3016016A (en) * 1959-07-02 1962-01-09 Cincinnati Milling Machine Co Reciprocating pump
US3143075A (en) * 1961-06-12 1964-08-04 Halliburton Co Pump
US3720484A (en) * 1970-03-04 1973-03-13 W Kirshsieper Hydraulic pressure transformer
US4343595A (en) * 1976-12-20 1982-08-10 Wells David L Hydraulic power booster apparatus
US4659292A (en) * 1976-12-20 1987-04-21 Dennis J. Lawman Hydraulic power booster apparatus
US4212597A (en) * 1978-03-22 1980-07-15 Salvador Gali Mallofre Pneumatic installations
FR2426166A1 (en) * 1978-05-18 1979-12-14 Control Concepts HYDRAULIC OSCILLATOR
FR2433660A1 (en) * 1978-07-29 1980-03-14 Kawasaki Heavy Ind Ltd HYDRAULIC CYLINDER, WITH INCREASED LOAD AT THE END OF STROKE
US4314447A (en) * 1979-07-02 1982-02-09 Carrier Corporation Refrigerant motor
WO1984002557A1 (en) * 1982-12-28 1984-07-05 Ethan A Silva A fluid intensifier
US4523895A (en) * 1982-12-28 1985-06-18 Silva Ethan A Fluid intensifier
US4659294A (en) * 1985-01-09 1987-04-21 Eimco Secoma, Societe Anonyme Hydrualic pressure amplifier
US4780064A (en) * 1986-02-10 1988-10-25 Flow Industries, Inc. Pump assembly and its method of operation
US4767384A (en) * 1987-04-06 1988-08-30 Ford Motor Company Fluid pressure amplifier for an infinitely variable drive
EP0754271A1 (en) * 1994-03-03 1997-01-22 John M. Simmons Pneumatically shifted reciprocating pump
EP0754271A4 (en) * 1994-03-03 1998-12-16 John M Simmons Pneumatically shifted reciprocating pump
USD380479S (en) * 1996-03-06 1997-07-01 Teledyne Industries, Inc. Modular pump
US5626467A (en) * 1996-04-04 1997-05-06 Teledyne Industries, Inc. Modular pump
US6729860B1 (en) * 2000-01-24 2004-05-04 Daniel A. Holt Pneumatically driven liquified gas booster pump
US20030099556A1 (en) * 2001-11-28 2003-05-29 Minibooster Hydraulics A/S Double-acting hydraulic pressure intensifier
US20040045430A1 (en) * 2002-09-09 2004-03-11 Vangstad Michael D. Reciprocating hydraulic motor utilizing a ramped valve yoke with a tripping spring
US20150053075A1 (en) * 2013-08-20 2015-02-26 Vianney Rabhi Reversible hydraulic pressure converter employing tubular valves
US9695840B2 (en) * 2013-08-20 2017-07-04 Vianney Rabhi Reversible hydraulic pressure converter employing tubular valves

Similar Documents

Publication Publication Date Title
US2949097A (en) Five position control valve having power float position
US2365095A (en) Power transmission
US3267815A (en) Cushioning structure for power cylinders
US4210064A (en) Method and device for braking the speed of movement of the piston of a plunger-cylinder device
US3818801A (en) Fluid actuating mechanism having alternatively selectable fast and slow modes of operation
US5226349A (en) Variable displacement hydrostatic pump and improved gain control thereof
US2648346A (en) Locking valve for hydraulic motors
US2448532A (en) Automatic power position hold for control valves
KR940001873B1 (en) Hydraulic-pneumatic cylinder device
US3045697A (en) Valve devices in particular for controlling the pressure of a hydraulic circuit
US2562615A (en) Hydraulic control system responsive to pressure and flow rate
GB1236613A (en) Axial plunger pump
EP0254353B1 (en) Free-piston motor with hydraulic or pneumatic energy transmission
GB1434561A (en) Dual range pressure dependent variable flow fluid delivery system
GB1140216A (en) Improvements in hydraulic or pneumatic reciprocating piston drive systems
US3236049A (en) Hydrostatic transmission
ES2043304T3 (en) Control circuit of hydraulic pumps for mobile machines for construction.
NL9101933A (en) Free piston motor with fluid pressure aggregate.
US2479856A (en) Multiple stage air compressor
GB1027184A (en) Hydraulic forming press
US3359727A (en) Hydrostatic transmission
US3173339A (en) Power control valve
GB1396439A (en) Hydraulic steering limitation means for hydrostatic steering installations more particularly for motor vehicles
GB1420424A (en) High pressure fluid intensifier and method
GB973397A (en) Improvements in variable speed hydromechanical power transmission