US3116607A - Hydraulic power system control - Google Patents

Hydraulic power system control Download PDF

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US3116607A
US3116607A US153447A US15344761A US3116607A US 3116607 A US3116607 A US 3116607A US 153447 A US153447 A US 153447A US 15344761 A US15344761 A US 15344761A US 3116607 A US3116607 A US 3116607A
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Prior art keywords
accumulator
valve
service line
exhaust
line
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US153447A
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English (en)
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Gratzmuller Jean Louis
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/02—Details
    • H01H33/28—Power arrangements internal to the switch for operating the driving mechanism
    • H01H33/30—Power arrangements internal to the switch for operating the driving mechanism using fluid actuator
    • H01H33/34—Power arrangements internal to the switch for operating the driving mechanism using fluid actuator hydraulic
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/027—Installations or systems with accumulators having accumulator charging devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/04—Accumulators
    • F15B1/08—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor
    • F15B1/24—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor with rigid separating means, e.g. pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2201/00—Accumulators
    • F15B2201/20—Accumulator cushioning means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2201/00—Accumulators
    • F15B2201/30—Accumulator separating means
    • F15B2201/31—Accumulator separating means having rigid separating means, e.g. pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2201/00—Accumulators
    • F15B2201/40—Constructional details of accumulators not otherwise provided for
    • F15B2201/41—Liquid ports
    • F15B2201/411—Liquid ports having valve means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2201/00—Accumulators
    • F15B2201/40—Constructional details of accumulators not otherwise provided for
    • F15B2201/41—Liquid ports
    • F15B2201/413—Liquid ports having multiple liquid ports

Definitions

  • This invention relates to the control of a hydraulic power system comprising la service line, an exhaust port or line and a hydraulic accumulator, preferably but not necessarily hydro-pneumatic, having a free piston, the control system or device enabling the service line to be connected selectively to the exhaust line or to the accumulator.
  • the invention is more especially (but not exclusively) adapted to systems in which the service line is connected to one or more single-acting hydraulic actuators with resilient, e.g., spring, return means and has been more especially devised to meet the requirements of an actuator, whose power stroke (under hydraulic pressure) must be completed without fail when once initiated and whose return stroke (under the effort of the resilient means) must not only be completed without fail but must be performed very rapidly, the exhausting of liquid from the actuator lbeing in no way impeded.
  • resilient e.g., spring
  • a further requirement, particularly for circuit-breaker operations, is that, once the actuator has completed its stroke in either direction, it must remain in its iinal position until the reverse action is initiated by human or other external agency (e.g. an automatic device responsive to overload or short-circuit in the case of a circuit-breaker).
  • human or other external agency e.g. an automatic device responsive to overload or short-circuit in the case of a circuit-breaker.
  • Retention of the actuator in its end of return stroke position may be ensured by providing that the venting of the service line to exhaust can only be terminated by positive, external control action; and retention of the actuator in its end of power stroke position by providing that the service line remains in communication with the accumulator :and therefore under pressure, until the service line is vented to exhaust by positive, external control action.
  • a further object of the invention is the provision, in combination with a hydraulic power system as rst herein dened, of a control device comprising a valve assembly having two settings, selectable by external agency, in one of which the service line is connected to exhaust, the accumulator being isolated, and in the other with the accumulator, the exhaust port or line being isolated, and a third or intermediate setting, in which the service line, and the accumulator are both connected to exhaust, and means actuated by the free piston of the accumulator on reaching Ia predetermined position in its liquid-expelling stroke for automatically bringing the valve assembly momentarily into said third setting and thereafter causing it, either by direct action or indirectly, to assume its first-mentioned setting, enabling the accumulator to be 1re-charged; the said position of the free piston being determined by the consideration of preventing the reserve of liquid in the accumulator from vanishing altogether or becoming too low for safety.
  • FIGURES 1 to 3 illustrate schematically, partially in section and highly simplified, an embodiment of the invention in three possible settings of the valve assembly
  • FIGURE 4 illustrates in greater detail one practical embodiment of lthe invention in axial section.
  • FIGURES l to 3 are intended to demonstrate the main features of the invention and its operation, all subordinate detail being omitted and to the form of the elements that are illustrated having been selected with a view to simplicity Iand clarity of the drawings rather than ultimate practical suitability.
  • FIGURE 4 on the other hand, is fully detailed. Reference characters common to FIGURE 4 and the other three figures identify the same or fully equivalent elements.
  • 1 is the accumulator and 2 is its free piston, ⁇ above which is the liquid chamber, 3 is the service line and 4 an exhaust line.
  • 5 is the body of the valve assembly, which is of the sliding piston type comprising two slidable closure members or lands 6 and 7 rigidly interconnected by an axial rod. Land 6 obstructs or exposes a port leading (via a duct 11) to the liquid chamber of the accumulator and land 7 obstructs or exposes an exhaust port leading to the exhaust line 4.
  • the service line 3 terminates in the valve body at a port, which is never obstructed, communicating with the space between lands 6 and 7.
  • a single-acting hydraulic jack 9 Rigidly connected to the rod uniting lands 6 and 7 is the piston 8 of a single-acting hydraulic jack 9, whose working chamber is above the piston, which is loaded from below by a return spring 10.
  • the working chamber of jack 9 is connected to duct 11 (and thereby to the accumulator) by a duct 12, in which is a manually operable cock 15, and to the exhaust line 4 by a duct 14 (branched from duct 12) in which is a manually operable cock 16, and to the service line 3 ⁇ by a duct 13, in which is a calibrated restrictor 17.
  • the rod interconnecting the lands 6 :and 7 is extended downwardly by a push rod 18, which extends, through a clearance opening in 4the head of the accumulator 1, into the liquid chamber of the accumulator to be met by the free piston 2 when it rises above a predetermined level (see FIGURE 3).
  • the control device illustrated in FIGURES l to 3 operates as follows:
  • FIGURE 2 shows the situation when the last-mentioned actuator is not energised, the service line being connected to the exhaust line, and therefore not pressurized, and the accumulator being isolated.
  • the jack 9 is also de-energised, since its working chamber communicates via duct 13 and the service line El ⁇ with the exhaust line 4 and is therefore at exhaust pressure, the cock 15 being closed. In this situation cock 16 will be kept closed.
  • the cock 15 is temporarily opened to admit liquid under the accumulator pressure to the jack 9 via duct 12.
  • the restrictor 17 by preventing rapid escape of liquid from the jack 9 via duct 13 into the as yet unpressurized service line, maintains the pressure in jack 9 causing the piston 8 to descend against the effort of spring 10 and bring the valve lands 6 and 7 into the setting of FIGURE 1, isolating the exhaust line 4 and connecting the service line 3 to the accumulator via duct 11.
  • the service line will now be under accumulator pressure and this pressure will be transmitted, via duct 13, to the working chamber of jack 9 maintaining the piston S and valve lands 6, 7 in the position of FIGURE. 1, whereupon the cock 1S is closed.
  • the service line 3 will therefore continue to be pressurized and the actuator 4t) connected thereto energised until, in normal circumstances, cock 16 is opened to connect the Working chamber of jack 9 to the exhaust line via duct 14, thus relieving the pressure in jack 9 and allowing spring 1@ to return the piston 8 and lands 6, 7 to the position of FIGURE 2.
  • the service line 3 will remain under pressure and liquid will flow from it into the working chamber of jack 9 via duct 13; but since this flow takes place through the restrictor 17, the latter imposes a large pressure drop between the service line 3 and the working chamber of jack 9, so that the relief of pressure in the latter is substantially unaffected and the rapid return of piston 8 by spring 10 to the position of FIGURE 2 is unimpeded.
  • this return movement before land 6 isolates the accumulator, loss of liquid from the latter via duct 14 and cock 16 is prevented because cock 15 has already been closed.
  • the piston Z will rise slowly all the time and not only during the charging of the last-mentioned actuator with consequent diminution of the reserve of liquid in the system; and if while the actuator is still charged, the device being in the condition shown in FIGURE 1, the piston 2 actually reaches the end of its stroke so that the accumulator can no longer make good the leakage loss, the actuator will discharge slowly through the leak and the apparatus it operates will return slowly to its end of cycle position. If the operated apparatus is a circuit-breaker and discharge of the actuator operating it effects or allows the circuit-breaking movement, such slow discharge of the actuator would have disastrous consequences.
  • the device as illustrated forestalls the possibility of unforeseen reduction of the reserve of liquid in the system to a dangerously low level by ensuring that, when the level of liquid reserve approaches or reaches such a low value, the service line is automatically vented to exhaust, thus rapidly discharging the actuator connected to the service line.
  • the sliding valve closure members of FIGURES 1 to 3 are replaced by seatable valve members, such as cones or balls, having a very small travel between their closed and fully open positions, thus promoting promptness of response of the device to control signals.
  • This embodiment comprises, as does that of FIGURES 1 to 3, a hydro-pneumatic accumulator having a cylinder 1 and free piston 2 with the liquid space above it, a connection for a service line 3, a valve body 5, valve closure members 6 and 7, a valve operating single-acting jack having a cylinder 9, a piston 8 and a return spring 10, a duct 12 connecting the jack cylinder 9 to the accumulator and containing a cock 15 and a duct 13 connecting the jack cylinder to the service line and containing a calibrated restrictor 17.
  • the head of the accumulator is formed by a block 19 into which the cylinder 1 is screwed; and on top of block 19 is mounted casing 24 constituting a reservoir of liquid at low pressure, being vented at the top to atmosphere or a lowpressure region by means not illustrated.
  • the valve body 5 is mounted in a Huid-tight manner in a central bore of the block 19, being secured therein by a ring nut 37, and extends downwardly into the accumulator cylinder 1 and upwardly into the reservoir 24.
  • the valve body has a straight-through axial bore 20 of varying diameter, the portions of enlarged diameter serving as guides for the cone valve members 6 and 7 and the shoulderings of this bore forming seatings for these valve members.
  • valve member 7 which is integral with the piston 8; and communication between passage 21 and passage 22 is controlled by valve member 6, which is not integral with valve member 7 but is seatable by a spring 26 and unseatable by a push rod 25 forming an extension of valve member 7.
  • valve member 6 which is not integral with valve member 7 but is seatable by a spring 26 and unseatable by a push rod 25 forming an extension of valve member 7.
  • FIGURE 4 corresponding to the valve-setting of FIG- URE 2
  • member 7 is fully unseated and member 6 is seated, thus putting the service line connection 3 into communication with the exhaust reservoir 24 and isolating the accumulator 1.
  • suiiicient to allow the spring 26 to seat the member 6 truly.
  • the push member 18, which functions in the same way as the rod 18 of FIGURES 1 to 3, is not attached to the valve member 6, but is in the form of a push button slidable in the open, lower end of bore 20, in which it is trapped by a circlip 34.
  • Push member 18 also has an upward extension forming the abutment of spring 26. In the position shown in FIGURE 4, spring 26 has seated valve member 6 and presses the push member 18 against its retaining circlip 34.
  • valve body is prolonged upwardly by a screwed-on extension having an axial bore 27 communicating with the working chamber of the jack cylinder portion 9 and housing the spring 10.
  • Duct 12 communicates with the bore 27 through a non-return, ball valve 28; and bore 27 communicates with a conventional safety valve 31 loaded by a calibrated spring 32.
  • Valve 31 vents the bore 27 to exhaust when the hydraulic pressure on the jack piston 8 exceeds a predetermined maximum value.
  • valve 31 is omitted for reasons hereinafter explained.
  • bore 27 is closed by a plug 29 having an axial bore communicating, via a side passage 35 with the exhaust reservoir 24, and terminating at its lower end in an opening communicating with bore Z7.
  • a ball 38 which is unseatable by a push rod 30 or by gravity in the absence of pressure in bore 27.
  • Rod 30 is normally retracted by a spring 39, allowing ball 38 to be seated, but can be depressed, against the consequence of spring 39, to unseat ball 38, by an electromagnet diagrammatically represented by a coil 36.
  • the passage 35 is the equivalent of duct 14 of FIGURES 1 to 3; and the ball valve assembly 38, 3i), 39, 36 is the equivalent of cock 16 of FIGURES 1 to 3.
  • the upward stroke of the accumulator piston 2 is limited by abutment against the lower end 33 of the valve body 5.
  • the clearance between the piston and its tinal abutment 33 is about half the total travel, between their fully unseated and seated positions, of the valve members 6 and 7 for reasons hereinafter explained.
  • valve body 5 extends far enough into the accumulator cylinder 1 to ensure that the piston 2 meets the push member 18 and thereafter its abutment 33 before the reserve of liquid in the accumulator is entirely exhausted; also that the construction adopted enables the accumulator cylinder 1 (with its piston 2) to be unscrewed and removed for replacement, if desired by a cylinder of different capacity, without disturbing the rest of the system.
  • FIGURE 4 The details of the construction illustrated in FIGURE 4 have been devised to simplify machining operations and to facilitate assembly and dismantling, as will be evident from inspection of the ligure.
  • a control device comprising valve means movable between an exhaust position, in which said valve means establishes communication between said service line and said exhaust line; a supply position, in which said valve means establishes a communication between said service line and said accumulator, and an intermediate position, in which said valve means establishes a communication between said exhaust line and both said service lines and accumulator; controllable means for selectively moving said valve means between said supply position and said exhaust position, said device further comprising a movable mechanical element operative on the valve means and extending into the accumulator and so actuabie by the said free piston when the latter reaches a predetermined position near the end of its liquid expelling stroke to move the valve means from said supply position to said intermediate position.
  • a control device including a chamber into which one end of each of said lines open, a Valve assembly within said chamber for controlling the openings into said lines, means operative on the valve assembly and controllable by an external agency for selecting valve assembly settings, in the first of which the service line communicates with the exhaust line, the accumulator line being closed, and in the second of which the service line communicates with the accumulator line, the exhaust line being closed, and means actuable by the free piston on its reaching a predetermined position in its liquid expelling stroke for temporarily bringing about a third, intermediate valve assembly setting in which the service line, the exhaust line and the accumulator line are all open and in mutual communication, without impeding further movement of the valve assembly from said third to said second setting.
  • a control device including a valve assembly into which one end of each of said lines open, for controlling the opening into said lines, means operative on the valve assembly and controllable by an external agency for selecting valve assembly settings, in the first of which the service line communicates with the exhaust line, the accumulator line being closed, and in the second of which the service line communicates with the accumulator line, the exhaust line being closed, and means actuable by the free piston on its reaching a predetermined position in its liquid expelling stroke for temporarily bringing about a third intermediate Valve assembly setting in which the service line, the exhaust line and the accumulator line are all open and in mutual communication, without impeding further movement of the valve assembly from said third to said second setting; said valve assembly comprising two closure members respectively adapted to close the accumulator and the exhaust lines, and the lastmentioned means including a push-member extending into
  • a control device including valve means movable, between an exhaust position, in which said valve means establish a communication between said service line and said exhaust line, and a supply position, in which said valve means establish a communication between said service line and said accumulator, through an intermediate position, in which said valve means establish a communication between said exhaust line and both said service line and said accumulator, means actuable by the free piston on its reaching a predetermined position on its liquid discharging stroke moving said valve means from said supply position to said intermediate position, a cylinder, a valve actuating member slidable in said cylinder, resilient means to urge said valve actuating member in a direction in which the latter moves said valve means to said exhaust position, said valve actuating member having a liquid pressure responsive working face to move said valve means under the effect of said liquid pressure against the action of said resilient means to said supply position.
  • Hydraulic power apparatus comprising a service line, eg. for connection to a single-acting hydraulic actuator with resilient return means, a hydraulic accumulator having a free piston, a low-pressure liquid reservoir, a valve body extending into the liquid chamber of the accumulator having an axial bore and passages extending from said bore and communicating respectively with said liquid chamber, the reservoir and the service line, said bore having therein two oppositely facing valve seatings, a first valve closure member slidable in said bore and seatable on one of said seatings to isolate the service line from the accumulator, a second valve closure member slidable in said bore and seatabie on the other of said seatings to isolate the service line from the reservoir, a push rod extending from the second said closure member through said bore to make contact with and unseat the first said closure member when the second said closure member is displaced towards its seating and before it reaches such seating, said bore extending beyond the second said valve member to constitute the working chamber of a single-acting hydraulic jack, the piston of which is an integral
  • Hydraulic power apparatus comprising a service line, e.g. for connection to a single-acting hydraulic actuator with resilient return means, a hydraulic accumulator having a free piston, a low-pressure liquid reservoir, a valve body extending into the liquid chamber of the accumulator having an axial bore and passages extending from said bore and communicating respectively with said liquid chamber, the reservoir and the service line, said bore having therein two oppositely facing valve seatings, a first valve closure member slidable in said bore and seatable on one of said seatings to isolate the service line from the accumulator, a second valve closure member slidable in said bore and seatable on the other of said seatings to isolate the service line from the reservoir, a push rod extending from the second said closure member through said bore to make contact with and unseat the first said closure member when the second said closure member is displaced towards its seating and before it reaches such seating, said bore extending beyond the second said valve member to constitute the working chamber of a single-acting hydraulic jack, the piston of which is an integral
  • a ball seatable to obstruct said channel by hydraulic pressure in said working chamber, controllable means for unseating said third closure member, a push member slidably mounted in the axial bore of the valve body and so trapped as normally to extend into the liquid chamber of the accumulator by a distance beyond the end of the valve body less than the total travel of said irst and second closure members between their seated and fully unseated positions and spring means trapped between said push-member and the iirst said closure member and operative to seat the latter.
  • Hydraulic power apparatus comprising a service line, eg. for connection to a single-acting hydraulic actuator with resilient return means, a hydraulic accumulator including a cylinder and a free piston, a block constituting the head of the accumulator into the lower part of which the cylinder is detachably secured, a casing mounted on said block and constituting, with the upper face of said block, a low-pressure liquid reservoir, a valve body secured in said block and extending downwardly into the liquid chamber of the accumulator above the free piston and upwardly into the reservoir, said valve body having an axial bore and passages extending from said bore and communicating respectively with said liquid chamber, the reservoir and the service line, said bore having therein two oppositely facing valve seatings, a first valve closure member slidable in said bore and seatable on one of said seatings to isolate the service line from the accumulator, a second valve closure member slidable in said bore and seatable on the other of said seatings to isolate the service line from the reservoir, a push rod extending from
  • Apparatus as dened in claim 6, including a springloaded safety valve for venting said working chamber to the reservoir, if and when the hydraulic pressure in said working chamber exceeds a predetermined value.
  • controllable means for unseating the third closure member include a second push member, electromagnetic means operative when excited to move said second push member to unseat the third closure member, and spring means operative to retract said second push member when said electromagnetic means is not excited.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
  • Fluid-Pressure Circuits (AREA)
US153447A 1960-11-28 1961-11-20 Hydraulic power system control Expired - Lifetime US3116607A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR845170A FR1281356A (fr) 1960-11-28 1960-11-28 Dispositif de commande pour circuit hydraulique

Publications (1)

Publication Number Publication Date
US3116607A true US3116607A (en) 1964-01-07

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ID=8743528

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US153447A Expired - Lifetime US3116607A (en) 1960-11-28 1961-11-20 Hydraulic power system control

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US (1) US3116607A (fr)
BE (1) BE610637A (fr)
CH (1) CH377204A (fr)
DE (1) DE1177438B (fr)
FR (1) FR1281356A (fr)
GB (1) GB929742A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3171254A (en) * 1960-07-06 1965-03-02 Leduc Rene Hydraulic accumulator assemblies
US4549564A (en) * 1983-10-26 1985-10-29 Deere & Company Pressure modulator valve

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0538501B1 (fr) * 1991-10-19 1994-12-28 BOLENZ & SCHÄFER MASCHINENFABRIK GmbH Accumulateur à cylindre avec dispositif pour déconnecter l'huile de charge, incorporé dans un circuit hydraulique
DE10238059B4 (de) 2002-08-20 2014-02-13 Liebherr-Aerospace Lindenberg Gmbh Federelement
CN113309743B (zh) * 2021-07-30 2021-10-08 山东辛丁技术有限公司 基于油田石化的液压蓄能器充气装置及其充气方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US920825A (en) * 1904-09-03 1909-05-04 Gen Electric Pumping system for hydrostatic apparatus.
US2283516A (en) * 1940-05-24 1942-05-19 Oilgear Co Hydraulic transmission
US2900960A (en) * 1954-01-15 1959-08-25 Gratzmuller Jean Louis Hydraulic control device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE512523C (de) * 1928-09-29 1930-11-17 M Mack Dipl Ing Hydraulischer Akkumulator
DE554062C (de) * 1930-07-19 1932-07-04 Wilhelm Groetzinger Hydraulischer Akkumulator mit Druckluftbelastung
DE600319C (de) * 1932-09-13 1934-07-18 Fried Krupp Grusonwerk Akt Ges Druckluftakkumulator mit Kolben
DE801931C (de) * 1948-10-02 1951-01-29 Hauhinco Maschf Vorrichtung zum Steuern der Druckmittelzufuhr von Foerderanlagen im Bergbau

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US920825A (en) * 1904-09-03 1909-05-04 Gen Electric Pumping system for hydrostatic apparatus.
US2283516A (en) * 1940-05-24 1942-05-19 Oilgear Co Hydraulic transmission
US2900960A (en) * 1954-01-15 1959-08-25 Gratzmuller Jean Louis Hydraulic control device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3171254A (en) * 1960-07-06 1965-03-02 Leduc Rene Hydraulic accumulator assemblies
US4549564A (en) * 1983-10-26 1985-10-29 Deere & Company Pressure modulator valve

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Publication number Publication date
DE1177438B (de) 1964-09-03
BE610637A (fr) 1962-03-16
FR1281356A (fr) 1962-01-12
CH377204A (fr) 1964-04-30
GB929742A (en) 1963-06-26

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