US3802319A - Cushioning device for hydraulic cylinders - Google Patents

Cushioning device for hydraulic cylinders Download PDF

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US3802319A
US3802319A US00212129A US21212971A US3802319A US 3802319 A US3802319 A US 3802319A US 00212129 A US00212129 A US 00212129A US 21212971 A US21212971 A US 21212971A US 3802319 A US3802319 A US 3802319A
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port
piston
housing
ring
fluid flow
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US00212129A
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J Bridwell
J Goade
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Caterpillar Inc
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Caterpillar Tractor Co
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Assigned to CATERPILLAR INC., A CORP. OF DE. reassignment CATERPILLAR INC., A CORP. OF DE. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: CATERPILLAR TRACTOR CO., A CORP. OF CALIF.
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20Other details, e.g. assembly with regulating devices
    • F15B15/22Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
    • F15B15/224Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having a piston which closes off fluid outlets in the cylinder bore by its own movement
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20Other details, e.g. assembly with regulating devices
    • F15B15/22Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
    • F15B15/222Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having a piston with a piston extension or piston recess which throttles the main fluid outlet as the piston approaches its end position

Definitions

  • a cushioning device for the reciprocable piston of a hydraulic cylinder having a valve associated with the piston to be automatically shiftable by fluid flow and pressure fluctuations to progressively restrict flow from the cylinder as the piston reaches the end of its retraction stroke, but to allow substantially unrestricted fluid flow into the cylinder to move the piston in the opposite direction.
  • Another object is to provide an improved cushioning device readily adaptable to progressively restrict the flow of fluid out of a hydraulic cylinder during its retraction stroke, particularly as the piston nears the end of such stroke, and yet provide substantially unrestricted fluid flow into the cylinder during its extension stroke.
  • FIG. I is a cross sectional view of a portion of a hydraulic cylinder utilizing the cushioning device of the present invention therein; 7
  • FIG. 2 is a sectional view of the cylinder taken along line lI-Il in FIG. 1;and
  • FIG. 3 is a cross sectional view similar to FIG. 1, but illustrating an alternative embodiment of the cushioning device.
  • a cushioning means is attached to a piston 12 of a hydraulic cylinder 13.
  • the piston is reciprocally mounted in a bore 14 of a tubular housing 16 of the cylinder.
  • the housing has an inletoutlet port means 18 formed through a sidewall thereof which communicates with a conduit 20, adapted to selectively communicate with a source of pressurized hydraulic fluid or a sump via conventional control means (not shown).
  • the port means is located closely adjacent to a closed end 22 of the cylinder.
  • the piston is secured to a rod 24 by a lock nut 26 and is provided with a reduced diameter section 28 to further provide a shoulder of the piston.
  • the section is provided with an annular groove 30 which seats a snap ring 32 therein.
  • An expansible chamber 34 is defined between the piston, the closed end of the cylinder and the housing to communicate with port means 18 and conduit 20.
  • Cushioning means 10 comprises a valve member constructed in the form of a cup-shaped annular member comprising a ring 36 and a radially inwardly extending flange 38.
  • a central opening 40 of the flange has a substantially larger diameter than the outer diameter of section 28 of the piston.
  • Flange 38 is retained axially by retention means comprising a shoulder of piston 12 and an annular washer 42 which abuts snap ring 32.
  • Ring 36 has a plurality of annular grooves 44 formed on its outer periphery. As best shown in FIG. 2, the ring has an outer diameter substantially smaller than the inner diameter of bore 14.-
  • FIG. 1 illustrates piston 12 at the end of its retraction stroke wherein the piston has moved leftwardly to exhaust fluid from chamber 34, through port 18 and into conduit 20.
  • ring 36 starts to cover the port, a pressure drop occurs across the port to force the ring upwardly.
  • substantial surface portions of the ring, along an arcuate segment thereof, move into substantial abutment with sidewall portions of the housing adjacent to the port.
  • annular grooves 44 are machined externally on the ring to provide an orifice affording limited continuous communication between chamber 34 and conduit 20.
  • pressurized fluid from conduit 20 forces ring 36 radi- 'ally inwardly to provide unrestricted fluid flow from port 18 to chamber 34.
  • FIG. 3 is a cross sectional view similar to FIG. I, but illustrating a modified cushioning device. Like numerals' are used to depict corresponding constructions with such numerals appearing in FIG. 3 being accompanied by an a. i
  • a cushioning means 10a is attached to a piston 12a of a hydraulic cylinder 13a.
  • the piston is reciprocally mounted in a bore 14a defined in a tubular housing 16a having an inlet-outlet port means 18a formed through a sidewall thereof to communicate with a conduit 20a.
  • the cushioning means is employed at the rod end of the cylinder, it could readily be adapted for use at the head end thereof, as suggested by FIG. I.
  • the piston is secured to a rod 24a by lock nut 26a.
  • An annular washer 27 is press-fitted (e.g., 0.0005-0.000l5 in. press-fit) or otherwise suitably secured on rod 24a to abut piston 12a.
  • the washer comprises an annular recess forming a eircurnferentially extending reduced diameter section or ledge portion 28a and a radially extending flange 29.
  • Cushioning means comprises a cup-shaped valve means or member comprising a ring 36a, having smooth and uninterrupted radially outer surface portions, and a radially inwardly extending flange 380.
  • a central opening 40a of the flange has a larger diameter than the outer diameter of ledge portion 28a of washer 27.
  • the flange is retained axially by retention means comprising an annular slot defined between radial portion 29 of the washer and piston 28a.
  • ring 36a has a diameter which is less than the inside diameter of bore 14a to permit limited radial movements of the valve member.
  • FIG. 3 illustrates piston 12a at the end of its extension stroke to exhaust fluid from the rod end of the cylinder.
  • a hydraulic cylinder comprising a tubular housing, a piston reciprocally mounted on a rod in said housing to define an expansible chamber therewith, port means formed through a sidewall of said housing, adjacent to a closed end thereof, for communicating a pressurized fluid to said chamber and cushioning means solely responsive to fluid flow between said chamber and said port means for gradually restricting fluid flow from said chamber to said port means when said piston moves axially toward said port means and for permitting substantially unrestricted fluid flow from said port means to said chamber when said piston moves axially away from said port means, said cushioning means comprising an annular member of cup shape having a ring with an outside diameter which is substantially smaller than the inside diameter of said housing positioned to move radially outwardly into abutment with said sidewall solely in response to exhaust fluid flow to at least substantially cover said port means and an integral, radially inwardly extending flange and annular retention means comprising a washer secured to said rod abutting said piston and defining a shoulder of reduced diameter and a
  • a cushioning device in combination with a piston disposed on a rod in a hydraulic cylinder having a fluid inlet-outlet port formed through a housing thereof, said cushioning device comprising valve means loosely disposed within said housing and being positionable by the piston into radial alignment with said port during retraction of the piston and being shiftable radially outwardly solely by fluid discharged from the cylinder to move into masked relationship over said port, said valve means comprising an annular ring member with an outside diameter which is substantially smaller than the inside diameter of said housing positioned to move radially outwardly into abutment with said housing to at least substantially cover said port and having a radially inwardly extending flange secured thereto, and retention means comprising a washer secured to said rod abutting said piston and defining a shoulder of reduced diameter and a radial portion of greater diameter to define an annular slot capturing said flange between said radial portion and said piston for guiding radial movement of said ring relative to said port.
  • valve means cooperates with said housing to form flow restricting means gradually providing a restricted passage for fluid discharged to said port to decelerate piston movement by causing a pressure drop across said port to maintain the ring of said valve means in said masked relationship and being movable radially inwardly out of said masking relationship in response to fluid flow from said port to said cylinder to permit substantially unrestricted fluid flow thereby.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)

Abstract

A cushioning device for the reciprocable piston of a hydraulic cylinder having a valve associated with the piston to be automatically shiftable by fluid flow and pressure fluctuations to progressively restrict flow from the cylinder as the piston reaches the end of its retraction stroke, but to allow substantially unrestricted fluid flow into the cylinder to move the piston in the opposite direction.

Description

United States Patent [193 Bridwell et al.
[ Apr. 9, 1974 CUSHIONING DEVICE FOR HYDRAULIC CYLINDERS [75] Inventors: John W. Bridwell, Peoria; James C.
Goade, Joliet, both of Ill.
[73] Assignee: Caterpillar Tractor Co., Peoria, Ill.
22 Filed: Dec. 27, 1971 21 App]. No.: 212,129
[52] US. Cl. 91/409 [51] Int. Cl. FlSb 15/22 [58] Field of Search 91/408, 409, 407, 405; 92/85 [56] 7 References Cited UNITED STATES PATENTS 3,296,942 1/1967 Nelson 92/85 1,844,107
2/1932 Sheperdson 91/409 4/1966 Aslon 91/408 3,247,767 3,314,657 4/1967 PrudHomme et al 91/408 3,323,422
6/1967 'Freese 91/409 Primary ExaminerPaul E. Maslousky Attorney, Agent, or Firm-Fryer, Tjensvold, Phillips & Lempio 57 I ABSTRACT A cushioning device for the reciprocable piston of a hydraulic cylinder having a valve associated with the piston to be automatically shiftable by fluid flow and pressure fluctuations to progressively restrict flow from the cylinder as the piston reaches the end of its retraction stroke, but to allow substantially unrestricted fluid flow into the cylinder to move the piston in the opposite direction.
4 Claims, 3 Drawing Figures PM'ENTEDAPR 9 i974 SHEU 1 8f 2 INVENTORS JOHN W. BRIDWELL JAMES C. GOADE m w w A iATENH-IH a law: 3302.319
sum 2 or 2 INVENTORS JOHN W BRIDWELL. JAMES C. GOADE ATTORNEYS 1 CUSHIONING DEVICE FOR HYDRAULIC CYLINDERS."
BACKGROUND OF THE INVENTION It is frequently desirable to provide a cushioning mechanism in a hydraulic cylinder for decelerating pis-- ton movement in a controlled manner as the piston approaches the end of its stroke. Many such cushioning devices are used commercially, but in most cases they are unduly complex and costly to manufacture.
SUMMARY AND OBJECTS OF THE INVENTION Accordingly, it is an object of the present invention to provide an efficient, non-complex and inexpensive cushioning device for use in hydraulic cylinders.
Another object is to provide an improved cushioning device readily adaptable to progressively restrict the flow of fluid out of a hydraulic cylinder during its retraction stroke, particularly as the piston nears the end of such stroke, and yet provide substantially unrestricted fluid flow into the cylinder during its extension stroke.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a cross sectional view of a portion of a hydraulic cylinder utilizing the cushioning device of the present invention therein; 7
FIG. 2 is a sectional view of the cylinder taken along line lI-Il in FIG. 1;and
FIG. 3 is a cross sectional view similar to FIG. 1, but illustrating an alternative embodiment of the cushioning device.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, a cushioning means is attached to a piston 12 of a hydraulic cylinder 13. The piston is reciprocally mounted in a bore 14 of a tubular housing 16 of the cylinder. The housing has an inletoutlet port means 18 formed through a sidewall thereof which communicates with a conduit 20, adapted to selectively communicate with a source of pressurized hydraulic fluid or a sump via conventional control means (not shown). The port means is located closely adjacent to a closed end 22 of the cylinder.
The piston is secured to a rod 24 by a lock nut 26 and is provided with a reduced diameter section 28 to further provide a shoulder of the piston. The section is provided with an annular groove 30 which seats a snap ring 32 therein. An expansible chamber 34 is defined between the piston, the closed end of the cylinder and the housing to communicate with port means 18 and conduit 20.
Cushioning means 10 comprises a valve member constructed in the form of a cup-shaped annular member comprising a ring 36 and a radially inwardly extending flange 38. A central opening 40 of the flange has a substantially larger diameter than the outer diameter of section 28 of the piston. Flange 38 is retained axially by retention means comprising a shoulder of piston 12 and an annular washer 42 which abuts snap ring 32. Ring 36 has a plurality of annular grooves 44 formed on its outer periphery. As best shown in FIG. 2, the ring has an outer diameter substantially smaller than the inner diameter of bore 14.-
OPERATION FIG. 1 illustrates piston 12 at the end of its retraction stroke wherein the piston has moved leftwardly to exhaust fluid from chamber 34, through port 18 and into conduit 20. When ring 36 starts to cover the port, a pressure drop occurs across the port to force the ring upwardly. As shown in FIG. 2, substantial surface portions of the ring, along an arcuate segment thereof, move into substantial abutment with sidewall portions of the housing adjacent to the port.
In this manner, fluid flow out of the port is progressively restricted as the ring covers the port to decelerate the piston as it approaches the end of its retraction stroke. In order to prevent complete blockage of the port, annular grooves 44 are machined externally on the ring to provide an orifice affording limited continuous communication between chamber 34 and conduit 20.
During the extension stroke of cylinder operation, pressurized fluid from conduit 20 forces ring 36 radi- 'ally inwardly to provide unrestricted fluid flow from port 18 to chamber 34.
FIG. 3 is a cross sectional view similar to FIG. I, but illustrating a modified cushioning device. Like numerals' are used to depict corresponding constructions with such numerals appearing in FIG. 3 being accompanied by an a. i
A cushioning means 10a is attached to a piston 12a of a hydraulic cylinder 13a. The piston is reciprocally mounted in a bore 14a defined in a tubular housing 16a having an inlet-outlet port means 18a formed through a sidewall thereof to communicate with a conduit 20a. Although the cushioning means is employed at the rod end of the cylinder, it could readily be adapted for use at the head end thereof, as suggested by FIG. I.
The piston is secured to a rod 24a by lock nut 26a. An annular washer 27 is press-fitted (e.g., 0.0005-0.000l5 in. press-fit) or otherwise suitably secured on rod 24a to abut piston 12a. The washer comprises an annular recess forming a eircurnferentially extending reduced diameter section or ledge portion 28a and a radially extending flange 29. Cushioning means comprises a cup-shaped valve means or member comprising a ring 36a, having smooth and uninterrupted radially outer surface portions, and a radially inwardly extending flange 380.
A central opening 40a of the flange has a larger diameter than the outer diameter of ledge portion 28a of washer 27. The flange is retained axially by retention means comprising an annular slot defined between radial portion 29 of the washer and piston 28a. In addition, ring 36a has a diameter which is less than the inside diameter of bore 14a to permit limited radial movements of the valve member.
OPERATION FIG. 3 illustrates piston 12a at the end of its extension stroke to exhaust fluid from the rod end of the cylinder. When ring 36a begins to cover port 18a at its leading, frusto-conically shaped free end-31 remote from flange 38a, fluid forces generated by fluid flow and the resulting pressure drop occasioned across the ring function to move outer surface portions of the ring into masking relationship with port 18a. Fluid flow out of conduit 20a is thus progressively restricted to dampen the retraction stroke.
Such restriction creates a pressure build-up in the head end of the cylinder whereupon a suitably calibrated pump relief valve (not shown) will open to reduce the flow to such head end and the linear speed of the piston will be reduced. Since the outer diameter of ring 360 is slightly smaller than the inner diameter of bore 14a, port 18a will not become fully blocked in its FIG. 3 position, During retraction of piston 120, leftwardly in FIG. 3, pressurized fluid from conduit 20 will force ring 36a radially upwardly away from inlet port 18a to provide substantially unrestricted fluid flow into expansible chamber 34a.
What is claimed is:
l. A hydraulic cylinder comprising a tubular housing, a piston reciprocally mounted on a rod in said housing to define an expansible chamber therewith, port means formed through a sidewall of said housing, adjacent to a closed end thereof, for communicating a pressurized fluid to said chamber and cushioning means solely responsive to fluid flow between said chamber and said port means for gradually restricting fluid flow from said chamber to said port means when said piston moves axially toward said port means and for permitting substantially unrestricted fluid flow from said port means to said chamber when said piston moves axially away from said port means, said cushioning means comprising an annular member of cup shape having a ring with an outside diameter which is substantially smaller than the inside diameter of said housing positioned to move radially outwardly into abutment with said sidewall solely in response to exhaust fluid flow to at least substantially cover said port means and an integral, radially inwardly extending flange and annular retention means comprising a washer secured to said rod abutting said piston and defining a shoulder of reduced diameter and a radial portion of greater diameter to define an annular slot capturing said flange between said radial portion and said piston for guiding radial movement of said ring relative to said port means.
2. The invention of claim 1 wherein radially outer surface portions of said ring are smooth and uninterrupted and terminate at a frusto-conically shaped free end of said ring, remote from said flange.
3. A cushioning device in combination with a piston disposed on a rod in a hydraulic cylinder having a fluid inlet-outlet port formed through a housing thereof, said cushioning device comprising valve means loosely disposed within said housing and being positionable by the piston into radial alignment with said port during retraction of the piston and being shiftable radially outwardly solely by fluid discharged from the cylinder to move into masked relationship over said port, said valve means comprising an annular ring member with an outside diameter which is substantially smaller than the inside diameter of said housing positioned to move radially outwardly into abutment with said housing to at least substantially cover said port and having a radially inwardly extending flange secured thereto, and retention means comprising a washer secured to said rod abutting said piston and defining a shoulder of reduced diameter and a radial portion of greater diameter to define an annular slot capturing said flange between said radial portion and said piston for guiding radial movement of said ring relative to said port.
4. The invention of claim 3 wherein said valve means cooperates with said housing to form flow restricting means gradually providing a restricted passage for fluid discharged to said port to decelerate piston movement by causing a pressure drop across said port to maintain the ring of said valve means in said masked relationship and being movable radially inwardly out of said masking relationship in response to fluid flow from said port to said cylinder to permit substantially unrestricted fluid flow thereby.

Claims (4)

1. A hydraulic cylinder comprising a tubular housing, a piston reciprocally mounted on a rod in said housing to define an expansible chamber therewith, port means formed through a sidewall of said housing, adjacent to a closed end thereof, for communicating a pressurized fluid to said chamber and cushioning means solely responsive to fluid flow between said chamber and said port means for gradually restricting fluid flow from said chamber to said port means when said piston moves axially toward said port means and for permitting substantially unrestricted fluid flow from said port means to said chamber when said piston moves axially away from said port means, said cushioning means comprising an annular member of cup shape having a ring with an outside diameter which is substantially smaller than the inside diameter of said housing positioned to move radially outwardly into abutment with said sidewall solely in response to exhaust fluid flow to at least substantially cover said port means and an integral, radially inwardly extending flange and annular retention means comprising a washer secured to said rod abutting said piston and defining a shoulder of reduced diameter and a radial portion of greater diameter to define an annular slot capturing said flange between said radial portion and said piston for guiding radial movement of said ring relative to said port means.
2. The invention of claim 1 wherein radially outer surface portions of said ring are smooth and uninterrupted and terminate at a frusto-conically shaped free end of said ring, remote from said flange.
3. A cushioning device in combination with a piston disposed on a rod in a hydraulic cylinder having a fluid inlet-outlet port formed through a housing thereof, said cushioning device comprising valve means loosely disposed within said housing and being positionable by the piston into radial alignment with said port during retraction of the piston and being shiftable radially outwardly solely by fluid discharged from the cylinder to move into masked relationship over said port, said valve means comprising an annular ring member with an outside diameter which is substantially smaller than the inside diameter of said housing positioned to move radially outwardly into abutment with said housing to at least substantially cover said port and having a radially inwardly extending flange secured thereto, and retention means comprising a washer secured to said rod abutting said piston and defining a shoulder of reduced diameter and a radial portion of greater diameter to define an annular slot capturing said flange between said radial portion and said piston for guiding radial movement of said ring relative to said port.
4. The invention of claim 3 wherein said valve means cooperates with said housing to form flow restricting means gradually providing a restricted passage for fluid discharged to said port to decelerate piston movement by causing a pressure drop across said port to maintain the ring of said valve means in said masked relationship and being movable radially inwardly out of said masking relationship in response to fluid flow from said port to said cylinder to permit substantially unrestricted fluid flow thereby.
US00212129A 1971-12-27 1971-12-27 Cushioning device for hydraulic cylinders Expired - Lifetime US3802319A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4207800A (en) * 1978-11-02 1980-06-17 Homuth Kenneth C Single directional sealing piston ring
JPS584804U (en) * 1981-06-30 1983-01-12 日立建機株式会社 cylinder device
US5024635A (en) * 1988-08-04 1991-06-18 Robinson Leslie K Relating to ram units in transmissions of the toroidal race, rolling traction type
WO2004055391A1 (en) * 2002-12-13 2004-07-01 Trw Automotive Gmbh Hydraulic cylinder
JP2017015108A (en) * 2015-06-29 2017-01-19 株式会社Taiyo Cushion device for hydraulic cylinder
US11067104B1 (en) * 2020-11-16 2021-07-20 Caterpillar Inc. Integrated cylinder piston and bearing as a hydraulic cushion

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1844107A (en) * 1929-05-25 1932-02-09 Morgan Construction Co Operating mechanism for metal-cutting shears
US3247767A (en) * 1962-12-03 1966-04-26 Alkon Products Corp Fluid cylinder
US3296942A (en) * 1965-03-08 1967-01-10 Int Harvester Co Deceleration control for piston of conventional hydraulic cylinder
US3314657A (en) * 1965-08-23 1967-04-18 Rucker Co Hydropneumatic cable tensioner
US3323422A (en) * 1965-08-02 1967-06-06 Cessna Aircraft Co Cushion stop for hydraulic cylinders

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1844107A (en) * 1929-05-25 1932-02-09 Morgan Construction Co Operating mechanism for metal-cutting shears
US3247767A (en) * 1962-12-03 1966-04-26 Alkon Products Corp Fluid cylinder
US3296942A (en) * 1965-03-08 1967-01-10 Int Harvester Co Deceleration control for piston of conventional hydraulic cylinder
US3323422A (en) * 1965-08-02 1967-06-06 Cessna Aircraft Co Cushion stop for hydraulic cylinders
US3314657A (en) * 1965-08-23 1967-04-18 Rucker Co Hydropneumatic cable tensioner

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4207800A (en) * 1978-11-02 1980-06-17 Homuth Kenneth C Single directional sealing piston ring
JPS584804U (en) * 1981-06-30 1983-01-12 日立建機株式会社 cylinder device
JPS6230563Y2 (en) * 1981-06-30 1987-08-06
US5024635A (en) * 1988-08-04 1991-06-18 Robinson Leslie K Relating to ram units in transmissions of the toroidal race, rolling traction type
WO2004055391A1 (en) * 2002-12-13 2004-07-01 Trw Automotive Gmbh Hydraulic cylinder
US20050226750A1 (en) * 2002-12-13 2005-10-13 Trw Automotive Gmbh Hydraulic cylinder
US7171888B2 (en) 2002-12-13 2007-02-06 Trw Automotive Gmbh Hydraulic cylinder
JP2017015108A (en) * 2015-06-29 2017-01-19 株式会社Taiyo Cushion device for hydraulic cylinder
US11067104B1 (en) * 2020-11-16 2021-07-20 Caterpillar Inc. Integrated cylinder piston and bearing as a hydraulic cushion

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Owner name: CATERPILLAR INC., 100 N.E. ADAMS STREET, PEORIA, I

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:CATERPILLAR TRACTOR CO., A CORP. OF CALIF.;REEL/FRAME:004669/0905

Effective date: 19860515

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Effective date: 19860515