EP0371176A1 - Pompe hydraulique à plusieurs étages synchronisée - Google Patents

Pompe hydraulique à plusieurs étages synchronisée Download PDF

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Publication number
EP0371176A1
EP0371176A1 EP88311330A EP88311330A EP0371176A1 EP 0371176 A1 EP0371176 A1 EP 0371176A1 EP 88311330 A EP88311330 A EP 88311330A EP 88311330 A EP88311330 A EP 88311330A EP 0371176 A1 EP0371176 A1 EP 0371176A1
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EP
European Patent Office
Prior art keywords
cylinder
piston
pistons
casing
chamber
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.)
Granted
Application number
EP88311330A
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German (de)
English (en)
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EP0371176B1 (fr
Inventor
Shojiro C/O Aioi Seiki Inc. Takeshima
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.)
Aioi Seiki Inc
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Aioi Seiki Inc
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Filing date
Publication date
Application filed by Aioi Seiki Inc filed Critical Aioi Seiki Inc
Priority to DE19883887150 priority Critical patent/DE3887150T2/de
Priority to EP88311330A priority patent/EP0371176B1/fr
Publication of EP0371176A1 publication Critical patent/EP0371176A1/fr
Application granted granted Critical
Publication of EP0371176B1 publication Critical patent/EP0371176B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/22—Synchronisation of the movement of two or more servomotors

Definitions

  • the present invention relates to a multi-boost synchronized hydraulic pump, and specifically relates to a multi-boost synchronized hydraulic pump which is optimum to synchronously drive a plurality of hydraulic cylinders by supplying these hydraulic cylinders or the like with hydraulic fluid of equal pressure and equal flow rate.
  • a hydraulic supply piping is branched and a flow control valve or a variable throttle valve is inserted in each branch piping and a hydraulic cylinder is connected to each branch piping, and thereby the flow rate of hydraulic fluid supplied to each cylinder is adjusted to become equal.
  • a synchronized hydraulic pump has been put in practical use which supplies hydraulic fluid of equal pressure and equal flow rate from each hydraulic operation chamber by synchronously driving plungers inserted slidably into a plurality of the hydraulic operation chambers installed in parallel by a driving piston.
  • a plurality of plunger holes are installed in parallel in a housing, and each plunger is inserted into each plunger hole, and these plungers are connected integrally to the driving piston at the end of the side opposite to the hydraulic operation chambers, and synchronized driving is performed by a common driving means.
  • this synchro­nized hydraulic pump has a problem of difficulty in synchronized driving of a plurality of cylinders having different loads.
  • the first object of the present invention is to provide a multi-boost synchronized hydraulic pump which reliably performs synchronized operation, and thereby supplies pressurized fluid of equal pressure and equal flow rate even if loads of a plurality of hydraulic operation chambers are not uniform.
  • a second object of the present invention is to provide a multi-boost synchronized hydraulic pump which can be manufactured easily at a low cost and wherein the number of the hydraulic operation chambers can be varied as required.
  • a third object of the present invention is to provide a multi-boost synchronized hydraulic pump wherein the discharging pressure and discharging rate can be set freely only by partly replacing parts.
  • a multi-boost synchronized hydraulic pump comprises a casing, cylinder chambers formed in series in the casing, a piston installed in each cylinder chamber, an intake port installed in a hydraulic operation chamber of each cylinder chamber, a discharge port which is independent from or in common with each intake port, a connecting shaft connecting a plurality of pistons in an integral fashion, and a driving means for synchronously driving a plurality of pistons through the connecting shaft.
  • a multi-boost synchronized hydraulic pump in accordance with the present invention comprises a casing, a plurality of cylinder chambers formed in a series in the casing, a piston installed slidably in each cylinder chamber, an intake port for supplying liquid to a hydraulic operation chamber formed on at least one side of the piston in each cylinder chamber, a discharge port for discharging pressurized liquid of each hydraulic operation chamber which is formed independent from or in common with each intake port, a connecting shaft integrally connecting a plurality of the above-mentioned pistons, and a driving means for synchronously driving a plurality of pistons through the connecting shaft.
  • This casing may be formed in an integral fashion, and, for example, may be formed in a divided manner corresponding to each cylinder chamber.
  • the portion of the casing corresponding to each cylinder chamber may be configurated with a partition wall portion sectioning one end of each cylinder and a peripheral wall portion of each cylinder connected continuously to this portion, or may be formed in a manner of dividing into the partition wall portion sectioning one end of each cylinder chamber and a portion corresponding to the peripheral wall of each cylinder chamber.
  • These portions formed in a divided fashion may be combined in a manner capable or incapable of disassembling.
  • a structure of connection by screws for example, a structure of connection by a common through bolt or the like has only to be adopted.
  • the configuration is made in a manner that the inner diameters of a plurality of cylinder chambers and the pressing areas of the pistons are formed equally, and thereby pressurized liquid of equal pressure and equal flow rate can be supplied from a plurality of hydraulic operation chambers.
  • the above-mentioned intake port for taking liquid into the hydraulic operation chamber may be dependent from the discharge port for discharging pressurized liquid from the hydraulic operation chamber, or may be an intake/discharge port which is used in common with the discharge port.
  • the intake/discharge port is installed, and in the case of using this as a multi-boost synchronized pump or distributor, the intake port and the discharge port are formed independently from each other.
  • each piston may be formed integrally with the connecting shaft, or may be fixed integrally in a manner that a plurality of pistons are sequentially fitted to the connecting shaft consisting of one through bolt and are tightened with nuts.
  • the interval between pistons is set through a spacer formed integrally with this piston or a spacer formed separately from the piston.
  • the above-mentioned driving means is not limited particularly provided that it can synchronously drive a plurality of pistons through the connecting shaft, and it is possible to use a conventional reciprocating driving means, for example, a return-spring-loaded type single-acting pneumatic cylinder or hydraulic cylinder, a double-acting type pneumatic cylinder or hydraulic cylinder, a solenoid type actuator, a motor and a cam driven by this motor, and a motor and a crank mechanism driven by this motor.
  • a conventional reciprocating driving means for example, a return-spring-loaded type single-acting pneumatic cylinder or hydraulic cylinder, a double-acting type pneumatic cylinder or hydraulic cylinder, a solenoid type actuator, a motor and a cam driven by this motor, and a motor and a crank mechanism driven by this motor.
  • a plurality of cylinder chambers are formed in series in the casing, and the pistons installed respectively in these cylinder chambers are connected integrally with the connecting shaft, and the hydraulic operation chamber is formed on one side of each cylinder chamber, and therefore by synchronously driving a plurality of pistons to the hydraulic operation chamber side by the driving means through the connecting shaft, liquid in each hydraulic operation chamber is pressurized, being discharged through the discharge port.
  • pressurized liquid of equal pressure and equal flow rate is discharged from a plurality of hydraulic operation chambers, and therefore by supplying pressurized liquid from each hydraulic operation chamber to each external hydraulic actuator, a plurality of actuators can be synchronously operated at an equal speed, can be synchronously operated with an equal stroke, or can be operated at an equal output.
  • the operating stroke of this actuator can be controlled stepwise.
  • different discharging pressures can be produced by different pressing areas of the hydraulic operation chambers by means of different inner diameters of the cylinder chambers or different outer diameters of the connecting shaft portions corresponding to each piston or spacers fitted thereto.
  • this pump can reliably discharge pressurized liquid in a synchronized fashion from a plurality of hydraulic operation chambers, and therefore a plurality of hydraulic actuators can be reliably driven synchronously.
  • each piston is free from moments caused by loads exerting on the other pistons, and operates smoothly in the cylinder chamber, and thereby poor operation or disabled operation can be prevented.
  • pressurized liquid of equal pressure and equal flow rate can be discharged from each hydraulic operation chamber, and, for example, a plurality of hydraulic cylinders can be synchronously operated at an equal speed, with an equal stroke, or at an equal output. Also, pressurized. liquid discharged from each hydraulic operation chamber is made to selectively join together and is supplied to the common hydraulic cylinder, and thereby, for example, the amount of protrusion of the hydraulic cylinder can be controlled stepwise.
  • different discharging pressures can be produced by different pressing areas of the hydraulic operation chambers by means of different inner diameters of the cylinder chambers or different outer diameters of the connecting shaft portions corresponding to each piston or spaces fitted thereto.
  • the casing can be formed with a structure of connecting divided units of casing corresponding to the respective cylinder chambers
  • the piston can also be configurated with divided units corresponding to the respective cylinder chambers, and in this case, by increasing or decreasing the number of the divided units of casing, the number of the cylinder chambers and the discharging pressure can be set freely according to the purpose, and elements other than the connecting shaft and the driving means can be configurated with a plurality of divided units of casing and pistons of the same kinds having relatively small-sized simple structures, and therefore the manufacturing cost can be remarkably reduced by mass-producting effect where a large number of pumps are manufactured.
  • Fig. 1 shows a multi-boost synchronized booster of one embodiment in accordance with the present invention, and this booster is suitable for applications to the hydraulic apparatuses, for example, for a carrying cart having lifting function, a metal mold fixing apparatus of press machine, injection molding machine or the like, a positioning apparatus of metal mold of press machine or work to be machined, and press shearing apparatus.
  • This multi-boost booster comprises a casing 1, four cylindrical cylinder chambers 2 formed in series inside this casing 1, a piston 3 installed slidably in each cylinder chamber 2, a connecting shaft 4 integrally connecting the four pistons 3, and a driving means 5 for synchronously driving the four pistons 3 reciprocatively through the connecting shaft 4.
  • the casing 1 is formed with four divided units of casing 1A corresponding to the respective cylinder chambers 2, and each divided unit of casing 1A is configurated integrally with a partition wall part 1a configurating the top end wall of the cylinder chamber 2 and a peripheral wall part 1b configurating the peripheral wall of the cylinder chamber 2.
  • These four divided units of cylinder 1A are stacked upward, and as shown in Fig. 2, being tightened to a casing 10 of the driving means 5 with four through bolts 22.
  • an inner diameter D1 of four cylinder chambers 2 is formed equally, and the length thereof is formed also equally.
  • a hydraulic operation chamber 6 is sectioned on the upper side of the piston 3 in each cylinder chamber 2, and each hydraulic operation chamber 6, a hydraulic path 7 connected thereto and a pressure receiving chamber 23a of a cylinder 23 at the end of the hydraulic path 7 are all filled with oil.
  • An intake/discharge port 8 making the hydraulic path 7 communicate with the hydraulic operation chamber 6 penetrates through the peripheral wall part 1b of each cylinder chamber 2, and opens to the top end of the inner peripheral surface of the hydraulic operation chamber 6.
  • the portion sectioned on the lower side of the piston 3 in each cylinder chamber 2 communicates with the open air through an air passage hole 9 formed on the partition wall part 1a of the cylinder chamber 2 to prevent the inner pressure from decreasing when the piston 3 ascends.
  • a top end wall 10a of the casing 10 of the driving means 5 is used also as a bottom end wall of the casing 1, and the air passage hole 9 of the lowermost cylinder chamber 2 is formed on this top end wall 10a.
  • each piston 3 On the top surface of each piston 3, a spacer 11 defining the interval between pistons 3 is formed integrally with each piston 3.
  • the thickness and the outer diameter D1 of four pistons 3 and the length (height) and the outer diameter D2 of the spacers 11 are formed equal respectively.
  • the top end of each spacer 11 penetrates through the partition wall la of the cylinder chamber 2 and is fitted into a recess formed on the bottom surface of the piston 3 on the upper side thereof.
  • Shaft holes 4a are formed in the center parts of four pistons 3 and spacers 11 along the whole length, and the connecting shaft 4 consisting of a long through bolt is inserted into the shaft holes 4a, and the bottom part of this connecting shaft 4 is inserted into a piston 12 of the pneumatic cylinder 5 and a spacer 13 defining the interval between the piston 12 and the piston 3 in the lowermost cylinder chamber 2, and is tightened together with a nut 14, and thereby the four pistons 3 and spacers 11, the spacer 13 and the piston 12 are connected integrally and coaxially.
  • the driving means 5 comprises a cylindrical casing 10 the top and bottom ends of which are closed and which configurates a single-type pneumatic cylinder provided with a compressed spring 17 for restoration, a cylinder chamber 15 formed inside this, a piston 12 installed slidably in this cylinder chamber 15, a pressure receiving chamber 16 sectioned on the lower side of this piston 12 in the cylinder chamber 15, and a compressed spring 17 installed on the upper side of the piston 12.
  • the portion sectioned on the upper side of the piston 12 in the cylinder chamber 15 communicates with the open air through an air passage hole 18 penetrating the peripheral wall of the casing 10, and a compressed air supply/exhaust apparatus 19 is connected to the pressure receiving chamber 16 through an intake/discharge port 19a.
  • This compressed air supply/exhaust apparatus 19 is configurated in a manner that when the control sequence is started manually or automatically, it supplies compressed air of a predetermined pressure to the pressure receiving chamber 16, drives the piston 12 upward, drives four pistons 3 upward through the piston 12 and the connecting shaft 4, and lifts them to the position where a limit switch 20 is turned to ON through the connecting shaft 4 and stops them at that position, and when the control sequence is ended manually or automatically, the pressure of the pressure receiving chamber 16 is released.
  • the position of the limit switch 20 can be adjusted by an adjust screw 21.
  • the inner diameter D1 of four cylinder chambers 2 and the outer diameter D2 of spacers 11 of four pistons 3 are formed equal respectively, and the four pistons 3 are connected integrally through the connecting shaft 4, and resultingly the stroke L thereof becomes the same, and therefore hydraulic fluid of equal pressure and equal flow rate is supplied to the hydraulic path 7 from the four hydraulic operation chambers 6 respectively in a synchronized manner, and is supplied to the pressure receiving chamber 23a of the cylinder 23, and the protruding speeds and the amounts of protrusion of the piston rods become accurately the same.
  • a load applied from the outside through each cylinder 23 acts on each piston 3, and the load exerting on each piston 3 exerts in the direction of the axial center thereof, generating no moment to the other pistons 3.
  • the divided unit of casing 1A and the piston 3 with the spacer 11 of the same kinds can be mass-­produced at low costs, and therefore the manufacturing cost of the multi-boost booster can be reduced to a great extent.
  • the casing 1 is formed in a manner that the divided units of casing 1A corresponding to each cylinder chamber 2 are connected in series, and therefore by increasing or decreasing the number of the divided units of casing 1A and the number of the pistons 3 and the spacers 11, this embodiment is applicable also to the case where the number of cylinders 23 of the driven side differs.
  • the casing 1 is formed in a divided manner corresponding to the cylinder chambers 2, but it is also possible to form the casing 1 integrally.
  • a plurality of cylinder chambers 2 are formed in the casing 1, and therefore, for example, as shown in Fig. 3, a cylindrical hole 1c is formed in the casing 1, and the partition wall parts 1a sectioning each cylinder chamber 2 and sleeves 31 configurating the inner peripheral wall of each cylinder chambers 2 between the partition wall parts 1a have only to be inserted alternately into the casing through this hole 1c.
  • the pressing area of each hydraulic operation chamber 6 is made to differ by means of different inner diameters of the sleeves 31, and thereby the discharging pressure of hydraulic fluid from each hydraulic operation chamber 6 is made to differ.
  • the above-mentioned divided unit of casing 1A can be further divided into a partition wall portion la configurating the end wall of the cylinder chamber 2 and a peripheral wall portion 1b configurating the peripheral wall of the cylinder chamber 2.
  • the connecting shaft 4 and each piston 3 may be configurated in a manner that each piston 3 is clamped by the stepped surface 4a formed on the connecting shaft 4 and a nut 32 screwed to the connecting shaft 4.
  • the position of the piston 3 is defined by the stepped surface 4a, and therefore the spacer 11 may be omitted.
  • the connecting shaft 4 in a stepped manner to have different diameters, the hydraulic force of each piston 3 differs on a hydraulic operation chamber 6 basis.
  • the cross-sectional area of each hydraulic operation chamber 6 is required to be made equal by fitting the sleeves having the same outer diameter to the connecting shaft 4 for the respective pistons 3.
  • Fig. 6 shows a lubricating oil supply pump suitable for a rolling apparatus in accordance with the present invention.
  • the cylinder chambers 2 having the same diameter and the same length are formed in series, and the pistons 3 having the same thickness and the same outer diameter are installed slidable in the respective cylinder chambers 2.
  • the four pistons 3 are connected integrally to the piston 12 of the driving means 5 through the connecting shaft 4 consisting of a through bolt likewise the case of Fig. 1.
  • the above-­mentioned driving means 5 is similar to the one in the above-mentioned first embodiment.
  • each intake port 8a is connected to the lubricating oil supply source 34 through an intake branch piping 36 wherein a check valve 35 is installed individually, and a check valve 38 is also installed in a discharge piping 37 connected to the discharge port 8b.
  • the outer diameter of the spacer 11 in the hydraulic pump 6 nearest to the driving means 5 is formed larger than the outer diameters of the spacers of the other hydraulic operation chamber 6, and the pressing area of that hydraulic operation chamber 6 is narrowed to generate a discharging pressure higher than those of the other hydraulic operation chambers 6.
  • the amount of hydraulic discharge from each hydraulic operation chamber 6 is controlled by controlling the stroke of the connecting shaft 4 likewise the first embodiment as shown in Fig. 1.
  • the connecting shaft 4 is brought in contact with the limit switch 20
  • the pressure of the pressure receiving chamber 16 of the driving means 5 is released, and the piston 12 and the connecting shaft 4 are pushed back in the direction of increasing the volume of the hydraulic operation chamber 6 by the spring 17.
  • the position of the limit switch 20 is adjusted by automatically rotating the adjust screw 21 by a required amount by a motor 38.
  • the piston 12 moves to the casing 1 side, and each piston 3 is driven in the direction of reducing the volume of the hydraulic operation chamber 6. Then, the pressure lubricating oil is discharged from each hydraulic operation chamber 6 to the discharge piping 37. At this time, the discharged pressures from the three upper hydraulic operation chambers 6 are the same, and the amount of hydraulic discharge thereof are also the same.
  • the discharging pressure of lubricating oil discharged from the hydraulic operation chamber 6 nearest to the driving means 5 is higher than those of lubricating oil discharged from the other hydraulic operation chambers 6, and the amount of discharge thereof is smaller than the amounts of discharge of the other hydraulic chambers 6.
  • the hydraulic operation chamber 6 is installed on one side of the piston 3, but, for example, as shown in Fig. 7, it is also possible to form the hydraulic operation chamber 6 on the both sides of the piston 3.
  • the driving means 5 is desirably configurated with a double-type pneumatic cylinder or hydraulic cylinder.
  • a multi-boost synchronized hydraulic pump is used wherein the intake port 8a and the discharge port 8b which are independent from each other are installed in place of the intake/discharge port 8 of each hydraulic operation chamber 6 of the multi-boost booster as shown in Fig. 1, and a hydraulic fluid supplying apparatus 39 is connected to each intake port 8a of this hydraulic pump through the intake branch piping 36 wherein the check valve 35 is installed, and each discharge port 8b is connected to a single-type cylinder 23A through a branch piping 37a having a cross valve 40 and a gathering piping 37 where four branch piping 37a having a cross valve 40 and a gathering piping 37 where four branch pipings 37a join.
  • each branch piping 37a The remaining port of the cross valve 40 of each branch piping 37a is connected to a drain piping 41, and the end of this drain piping 41 is opened to an oil tank 42 of a hydraulic fluid supplying apparatus 39.
  • Change-over of connection of each cross valve 40 is controlled by a controlling circuit (not illustrated).
  • the amount of oil supplied to the pressure receiving chamber 23a of the cylinder 23A can be controlled stepwise, and the stroke of that cylinder 23A can be controlled stepwise.
  • configuration is made in a manner that the stroke of each piston 3 in the casing 1 differs.
  • each piston 3 when the discharging pressure is made to differ by means of a different cross-sectional area of each hydraulic operation chamber 6, the stroke of each piston 3 is made to differ as described above, and thereby the amount of discharge of pressurized liquid having different discharging pressures which is discharged from each hydraulic operation chamber 6 can be made equal, and a plurality of cylinders receiving a different load can also be synchronously driven at an equal speed.
  • the multi-boost synchronized hydraulic pump in accordance with the present invention is applied to a booster supplying pressurized liquid to a plurality of hydraulic actuators or a pump or distributor supplying pressurized liquid intermittently, and for a booster, it is applied, for example, to a carrying cart having a lifting function, a stationary lifting apparatus, a positioning apparatus of metal mold of press machine or work to be machined, a metal mold fixing apparatus of press machine or injection molding machine and a hydraulic apparatus such as a press machine and a shearing apparatus. Also, for a pump or distributor, it is applied, for example, to a lubricating oil supply pump of a rolling mill.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
EP88311330A 1988-11-30 1988-11-30 Pompe hydraulique à plusieurs étages synchronisée Expired - Lifetime EP0371176B1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE19883887150 DE3887150T2 (de) 1988-11-30 1988-11-30 Hydraulische mehrstufige Gleichlaufpumpe.
EP88311330A EP0371176B1 (fr) 1988-11-30 1988-11-30 Pompe hydraulique à plusieurs étages synchronisée

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP88311330A EP0371176B1 (fr) 1988-11-30 1988-11-30 Pompe hydraulique à plusieurs étages synchronisée

Publications (2)

Publication Number Publication Date
EP0371176A1 true EP0371176A1 (fr) 1990-06-06
EP0371176B1 EP0371176B1 (fr) 1994-01-12

Family

ID=8200303

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88311330A Expired - Lifetime EP0371176B1 (fr) 1988-11-30 1988-11-30 Pompe hydraulique à plusieurs étages synchronisée

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EP (1) EP0371176B1 (fr)
DE (1) DE3887150T2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1016706A5 (nl) * 2005-07-26 2007-05-08 Haco Nv Persinrichting met verbeterd parallelhoudsysteem.
CN101832459A (zh) * 2010-04-29 2010-09-15 浙江流遍机械润滑有限公司 叠加式多点油脂润滑泵

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1235486A (fr) * 1959-05-27 1960-07-08 Rech Etudes Production Sarl Dispositif de synchronisation pour un groupe de commandes hydrauliques ou pneumatiques
GB1128962A (en) * 1965-01-27 1968-10-02 Rotary Hoes Ltd Means for providing equal volume, pressurised supplies of an hydraulic fluid to operate at least two identical rams simultaneously
FR1575806A (fr) * 1968-05-10 1969-07-25
US3783620A (en) * 1971-09-03 1974-01-08 J Moe Synchronizer for hydraulic cylinders

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH058325Y2 (fr) * 1986-12-26 1993-03-02

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1235486A (fr) * 1959-05-27 1960-07-08 Rech Etudes Production Sarl Dispositif de synchronisation pour un groupe de commandes hydrauliques ou pneumatiques
GB1128962A (en) * 1965-01-27 1968-10-02 Rotary Hoes Ltd Means for providing equal volume, pressurised supplies of an hydraulic fluid to operate at least two identical rams simultaneously
FR1575806A (fr) * 1968-05-10 1969-07-25
US3783620A (en) * 1971-09-03 1974-01-08 J Moe Synchronizer for hydraulic cylinders

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1016706A5 (nl) * 2005-07-26 2007-05-08 Haco Nv Persinrichting met verbeterd parallelhoudsysteem.
CN101832459A (zh) * 2010-04-29 2010-09-15 浙江流遍机械润滑有限公司 叠加式多点油脂润滑泵

Also Published As

Publication number Publication date
EP0371176B1 (fr) 1994-01-12
DE3887150D1 (de) 1994-02-24
DE3887150T2 (de) 1994-04-28

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