US3704650A - Hydraulic jack stroke cushioning means - Google Patents

Hydraulic jack stroke cushioning means Download PDF

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Publication number
US3704650A
US3704650A US128822A US3704650DA US3704650A US 3704650 A US3704650 A US 3704650A US 128822 A US128822 A US 128822A US 3704650D A US3704650D A US 3704650DA US 3704650 A US3704650 A US 3704650A
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US
United States
Prior art keywords
rod
sleeve
piston
bore
housing
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
US128822A
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English (en)
Inventor
Lawrence F Berg
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.)
Caterpillar Inc
Original Assignee
Caterpillar Tractor Co
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Filing date
Publication date
Application filed by Caterpillar Tractor Co filed Critical Caterpillar Tractor Co
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Publication of US3704650A publication Critical patent/US3704650A/en
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.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2203—Arrangements for controlling the attitude of actuators, e.g. speed, floating function
    • 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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
    • F15B15/222—Other 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 hydraulic jack is provided with means to cushion the piston and rod assembly at the end of its stroke.
  • the cushioning means comprises a pair of resiliently supported sleeves, one placed on each side of the piston, that cooperate with respective bores in the housing of the jack to serve to progressively restrict the flow of fluid to an exhaust port as the piston nears the end of its stroke.
  • the resilient mounting of the sleeves comprising annular elastomeric seals, permits limited radial movement thereof with respect'to the piston to compensate for any eccentricity of the bores relative to the piston.
  • the present invention relates to hydraulic jacks having means to cushion the piston and rod assembly at the end of its stroke and pertains more particularly to the elimination of the concentricity and sealing problems between several components making up the cushioning means. In most hydraulically actuated implements, it is necessary that the piston and rod assembly travel at a high rate of speed in order to achieve efficient operation.
  • the primary object of the present invention is to provide a hydraulic jack that overcomes the above disadvantages of the prior art.
  • Another object of the present invention is to provide a hydraulic jack that employs a simple, inexpensive and effective means for cushioning the stroke of the piston and rod assembly.
  • a further and related object is to provide a stroke cushioning means for hydraulic jacks wherein at least one cushioning sleeve is carried by thepiston to engage a bore in the jack housing to restrict flow therefrom.
  • the sleeve is supported on the piston by an annular elastomeric seal providing the dual function of permitting limited radial movement of the sleeve to compensate for any eccentricity of the bore relative to the piston and cushioning sleeve support and of affording a fluid tight seal thereat.
  • a hydraulic jack is cushioned by restricting the fluid being expelled from the-bore of the jack. This is accomplished by sleeve and bore combinations that restrict the exhaust port prior to contact of the piston and rod assembly with the end of the jack.
  • FIG. 1 is a side elevational view of a machine equipped with one or more hydraulic jacks
  • FIG. 2 is a fragmentary cross-sectional view of the head end section of a hydraulic jack
  • FIG. 3 is a fragmentary cross-sectional view of the rod end section of a hydraulic jack
  • FIG. 4 is a partial cross-sectional view taken along the lines of IV-IV of FIG. 2;
  • FIG. 5 is a partial cross-sectional view taken along lines V-V of FIG. 3;
  • FIG. 6 is an enlarged cross-sectional view of a seal ring employed in the hydraulic jack.
  • FIG. 1 there is illustrated a machine employing several hydraulic jacks to manipulate the implements mounted on a machine.
  • a jack 10 for example, is used to manipulate a stick 12, relative to a boom 14 of an excavator machine, shown generally at'16.
  • the rod of the hydraulic jack is fastened to the stick by a pin joint 18, and the head end of the jack is secured to the boom by a pin joint 20.
  • Thejack' is activated through a conventional control valve 22, which is manipulated by a control handle in the operator station through a mechanical linkage (not shown).
  • a pump 24 is utilized to supply the fluid under pressure necessary to operate the jack, through control valve 22.
  • a conventional re lief valve 26 is located in the circuitry to protect against unduly high circuit pressures.
  • a housing 36 thereof includes a suitable extension 38 for anchoring the jack to boom 14 by pin joint 20.v
  • a port 40 in the housing communicates with line 32 to communicate fluid into or out of an expansible actuating chamber 42 defined by the end wall section of the housing and a piston and rod assembly comprising a piston 44 and an elongate rod 46 reciprocably mounted in the housing for movement along the longitudinal axis thereof.
  • Port 40 is in communication with chamber 42 via a cylindrical bore 48 formed in the end wall of the housing, the bore being substantially coaxial with respect to piston 44.
  • the head end cushioning means comprises a metallic cylindrical sleeve or ring 50 solely mounted on a cylindrical spacer 52, forming a cylindrical extension of rod 46, by an annular elastomeric combined sealing and centering means, shown in the form of a seal ring 54.
  • Radial spacer 52 and an axial spacer 56 are secured in an axial relationship by a cap screw 58.
  • Spacer or stop ring 56 further serves to enlarge the contact area of the piston and rod assembly that contacts cooperating stop means 59 formed internally on housing 36.
  • Seal ring 54 serves two functions in that it allows limited radial floating movements of sleeve 50 for piloting the sleeve into bore 48, as described hereinafter, and prevents passage of fluid between the sleeve and spacer 52 in one direction.
  • Ring 54 is disposed in a groove 53 in sleeve 50 and preferably comprises an approximate U-shaped crosssection.
  • An inner lip 55 of ring 54 extends radially inwardly and contacts the outside diameter of spacer 52 to function like a check valve in that fluid can flow between sleeve 50 and spacer 52 in a direction toward expansible chamber 42, but cannot flow in the opposite direction.
  • FIG. 6 more clearly illustrates the ring in its relaxed condition prior to installation (phantom lines) and its compressed installed condition (solid lines).
  • piston 44 and rod 46 will move toward the left in FIG. 2 to expel fluid from chamber 42, through the bore 48, port 40 andline 32.
  • sleeve 50 will enter into telescopic relationship with bore 48.
  • Initial piloting of sleeve 50 will be affected by the flow of fluid past the end of sleeve 50 into bore 48.
  • -Since ring 54 will allow slight radial movements of the sleeve, the sleeve will accurately and automatically self-center itself into the bore.
  • the sleeve is preferably constructed with a stepped-down outside diameter to provide restricted passage means comprising a smaller diametered first end portion 60 arranged to enter bore 48 first to provide gradual restriction to the flow of fluid from chamber 42. Subsequently, a larger diametered second end portion 62 of the sleeve enters the bore and further gradually restricts or governs the flow of fluid out of the chamber. A, much closer tolerance can be maintained between portion 62 and the bore because 'of the piloting action of smaller portion 60 with the bore.
  • the cushioning means employed on the rod end of the jack, illustrated in FIG. 3, is somewhat different in construction than that used for the head end. Although the configuration used could be the same for both applications, the volume of fluid expelled from a rod end a bore 70 formed through the end cap and fluid is prevented from leaking therepast by means of a conventional seal 71. When the jack is extended, the piston and rod assembly moves toward the right to its FIG. 3
  • the rod end cushioning means comprises a sleeve 76 mounted in an annular recess formed in rod 46 solely by an annular elastomeric combined sealing and centering means or seal ring 78, similar in construction to ring 54 (FIG. 6).
  • the seal ring serves the dual function of piloting sleeve 76 as it starts to enter bore 72 and of preventing leakage of fluid between the sleeve and rod. 7
  • a pump flow of 131 gpm into the rod end of a jack containing a 7-inch diameter piston secured to a 4%-inch diameter rod would, during maximum retraction acceleration (l2l.5 feet per minute), cause a flow of 242gpm out of the head end chamber 42 of the jack.
  • maximum extension acceleration 65 feet per minute
  • the flow rate is dependent on the difexpansible actuating chamber 66 is less than the 6 ference in volume between the two chambers of the hydraulic jack.
  • governing or restriction of the fluid flow out of the rod end chamber is more critical than governing the much larger-flow being expelled from the head end chamber of the jack.
  • a fluid actuated hydraulic jack disposed on a longitudinal axis thereof and comprising a housing
  • a piston assembly including a rod and attached piston, reciprocally mounted in said housing for movement along said axis and defining at least one expansible actuating chamber therewith,
  • said cushioning means comprising,
  • annular elastomeric combined sealing and centering means solely mounting said sleeve on said rod for permitting limited radial floating movements of said sleeve relative to said rod, transversely on said axis, and
  • restricted passage means defined between said bore and said sleeve for gradually restricting fluid flow therebetween upon progressive, axial movement of a first end of said sleeve into said bore, said restricted passage means comprising means formed on the periphery of said sleeve and cooperating with said bore to provide a larger flow area at a first end of said sleeve than at a second, opposite end thereof.
  • said restricted passage means comprises at least one tapered groove formed on the periphery of said sleeve and disposed in axial alignment with respect to the longitudinal axis of said jack.
  • said rod comprises an axially aligned cylindrical extension attached to an end thereof, said sleeve mounted on said extension, a circumferentially extending groove formed internally on said sleeve and having said combined sealing and centering means disposed therein for solely mounting said sleeve on said extension.
  • the hydraulic jack of claim 1 wherein said housing comprises an end cap attached to an end thereof, said rod extending through a bore formed in said end cap and said passage means formed in said end cap.
  • said seal ring comprises a body portion and at least one flexible lip means normally circumferentially contacting outer surface portions of said rod, said flexible lip means extending generally toward said expansible chamber to prevent pressurized fluid flow from said expansible chamber to said passage means but to permit pressurized fluid flow from said passage means to said expansible chamber.
  • a fluid actuated hydraulic jack disposed on a longitudinal axis thereof and comprising a housing
  • a piston assembly including a rod and attached piston, reciprocally mounted in said housing for movement along said axis and defining at least one expansible actuating chamber therewith,
  • At least one cushioning means attached to said rod on a side of said piston and disposed in axial alignment with said bore for closing said bore upon movement of said piston assembly theretowards,
  • said cushioning means comprising,
  • annular elastomeric combined sealing and centering means solely mounting said sleeve on said rod for permitting limited radial floating movements of said sleeve relative to said rod, transversely on said axis,
  • said rod comprising an axially aligned cylindrical extension attached to an end thereof, said sleeve mounted on said extension, a circumferentially extending groove formed internally on said sleeve and having said combined sealing and centering means disposed therein for solely mounting said sleeve on said extension.
  • the hydraulic jack of claim 10 furthercomprising an annular stop ring attached to said rod andaxially aligned cooperating stop means formed internally on said housing for engaging said stop ring upon maximum retraction of said jack.
  • a fluid actuated hydraulic jack disposed on a longitudinal axis thereof and comprising a housing
  • a piston assembly including a rod and attached piston, reciprocally mounted in said housing for movement along said axis and defining at least one expansible actuating chamber therewith,
  • said cushioning means comprising,
  • annular elastomeric combined sealing and centering means solely mounting said sleeve on said rod for permitting limited radial floating movements of said sleeve relative to said rod, transversely on said axis,
  • said seal comprising a body portion and at least one flexible lip means normally circumferentially contacting outer surface portions of said rod, said flexible lip means extending generally toward said expansible chamber to prevent pressurized fluid flow from said expansible chamber to said passage means but to permit pressurized fluid flow from said passage means to said expansible chamber.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Actuator (AREA)
  • Lifting Devices For Agricultural Implements (AREA)
US128822A 1971-03-29 1971-03-29 Hydraulic jack stroke cushioning means Expired - Lifetime US3704650A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12882271A 1971-03-29 1971-03-29

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US3704650A true US3704650A (en) 1972-12-05

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US128822A Expired - Lifetime US3704650A (en) 1971-03-29 1971-03-29 Hydraulic jack stroke cushioning means

Country Status (10)

Country Link
US (1) US3704650A (fr)
JP (1) JPS5521208B1 (fr)
AU (1) AU460377B2 (fr)
BE (1) BE779391A (fr)
CA (1) CA940014A (fr)
DE (1) DE2214032A1 (fr)
FR (1) FR2132013B1 (fr)
GB (1) GB1342548A (fr)
IT (1) IT948664B (fr)
SE (1) SE374949B (fr)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3913451A (en) * 1974-08-30 1975-10-21 Cincinnati Milacron Inc Hydraulic cylinder with cushioning means
US3964370A (en) * 1974-07-15 1976-06-22 Parker-Hannifin Corporation Cushioning means for hydraulic cylinder
US4006666A (en) * 1975-05-22 1977-02-08 Towmotor Corporation Cushioning device for a hydraulic jack
US4033235A (en) * 1976-01-26 1977-07-05 Caterpillar Tractor Co. Fluid operated ram
US4064788A (en) * 1976-07-29 1977-12-27 Parker-Hannifin Corporation Cushioning means for hydraulic cylinder
FR2479389A1 (fr) * 1980-03-26 1981-10-02 Komatsu Mfg Co Ltd Dispositif d'amortissement de course de cylindre hydraulique
US4386555A (en) * 1979-02-09 1983-06-07 Sperry Corporation Hydraulic cylinder cushion device
US4517878A (en) * 1981-10-20 1985-05-21 Hitachi Construction Machinery Co., Ltd. Shock absorbing device for hydraulic cylinder
EP0068495B1 (fr) * 1981-06-30 1986-03-12 Hitachi Construction Machinery Co., Ltd. Dispositif amortisseur pour un cylindre hydraulique
EP1001174A1 (fr) * 1998-05-29 2000-05-17 Hitachi Construction Machinery Co., Ltd. Cylindre hydraulique
EP1050686A3 (fr) * 1999-05-05 2002-01-02 Lucas Industries Limited Assemblage de piston et de cylindre, et limiteur de débit pour celui-ci
US20050263001A1 (en) * 2004-05-28 2005-12-01 Caterpillar Inc. Hydraulic cylinder having a snubbing valve
US20060230649A1 (en) * 2005-01-27 2006-10-19 Enzo Gusella Actuator device, particularly for an orange-peel bucket
US20080289486A1 (en) * 2007-05-22 2008-11-27 Nobuyuki Kobayashi Cushion ring and fluid-pressure cylinder
US20150377262A1 (en) * 2013-02-13 2015-12-31 Messier-Dowty Inc. Modular actuator with snubbing arrangement
US11067104B1 (en) * 2020-11-16 2021-07-20 Caterpillar Inc. Integrated cylinder piston and bearing as a hydraulic cushion
US11319972B1 (en) * 2021-05-11 2022-05-03 Caterpillar Inc. Hydraulic cylinder snubbing retention arrangement
US20220228640A1 (en) * 2019-05-31 2022-07-21 Hydra Dyne Technology Inc. Stroke cushioning in piston and cylinder devices

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU1164083A (en) * 1982-02-11 1983-08-18 Sperry Ltd. Control valve for a fluid operated piston-cylinder assembly
DE19836422C2 (de) * 1998-08-12 2002-10-24 Mannesmann Rexroth Ag Druckmittelbetätigter Arbeitszylinder

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2493602A (en) * 1947-12-31 1950-01-03 Vance C Sterrett Pressure fluid motor
US2642845A (en) * 1950-12-20 1953-06-23 Westinghouse Air Brake Co Piston cushioning apparatus
US2704996A (en) * 1952-07-17 1955-03-29 Hannifin Corp Fluid operated cylinder with adjustable cushion

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2493602A (en) * 1947-12-31 1950-01-03 Vance C Sterrett Pressure fluid motor
US2642845A (en) * 1950-12-20 1953-06-23 Westinghouse Air Brake Co Piston cushioning apparatus
US2704996A (en) * 1952-07-17 1955-03-29 Hannifin Corp Fluid operated cylinder with adjustable cushion

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3964370A (en) * 1974-07-15 1976-06-22 Parker-Hannifin Corporation Cushioning means for hydraulic cylinder
US3913451A (en) * 1974-08-30 1975-10-21 Cincinnati Milacron Inc Hydraulic cylinder with cushioning means
US4006666A (en) * 1975-05-22 1977-02-08 Towmotor Corporation Cushioning device for a hydraulic jack
US4033235A (en) * 1976-01-26 1977-07-05 Caterpillar Tractor Co. Fluid operated ram
US4064788A (en) * 1976-07-29 1977-12-27 Parker-Hannifin Corporation Cushioning means for hydraulic cylinder
US4386555A (en) * 1979-02-09 1983-06-07 Sperry Corporation Hydraulic cylinder cushion device
FR2479389A1 (fr) * 1980-03-26 1981-10-02 Komatsu Mfg Co Ltd Dispositif d'amortissement de course de cylindre hydraulique
EP0068495B1 (fr) * 1981-06-30 1986-03-12 Hitachi Construction Machinery Co., Ltd. Dispositif amortisseur pour un cylindre hydraulique
US4517878A (en) * 1981-10-20 1985-05-21 Hitachi Construction Machinery Co., Ltd. Shock absorbing device for hydraulic cylinder
EP1001174A4 (fr) * 1998-05-29 2005-12-14 Hitachi Construction Machinery Cylindre hydraulique
EP1001174A1 (fr) * 1998-05-29 2000-05-17 Hitachi Construction Machinery Co., Ltd. Cylindre hydraulique
US6386088B1 (en) * 1998-05-29 2002-05-14 Hitachi Construction Machinery, Co. Ltd. Hydraulic cylinder
EP1050686A3 (fr) * 1999-05-05 2002-01-02 Lucas Industries Limited Assemblage de piston et de cylindre, et limiteur de débit pour celui-ci
US20050263001A1 (en) * 2004-05-28 2005-12-01 Caterpillar Inc. Hydraulic cylinder having a snubbing valve
US7121185B2 (en) * 2004-05-28 2006-10-17 Caterpillar Inc. Hydraulic cylinder having a snubbing valve
US20060230649A1 (en) * 2005-01-27 2006-10-19 Enzo Gusella Actuator device, particularly for an orange-peel bucket
US20080289486A1 (en) * 2007-05-22 2008-11-27 Nobuyuki Kobayashi Cushion ring and fluid-pressure cylinder
US7900549B2 (en) * 2007-05-22 2011-03-08 Kayaba Industry Co, Ltd Cushion ring and fluid-pressure cylinder
CN102927082A (zh) * 2007-05-22 2013-02-13 萱场工业株式会社 垫圈和液压缸
CN102927082B (zh) * 2007-05-22 2015-04-22 萱场工业株式会社 垫圈和液压缸
US20150377262A1 (en) * 2013-02-13 2015-12-31 Messier-Dowty Inc. Modular actuator with snubbing arrangement
US10151333B2 (en) * 2013-02-13 2018-12-11 Safran Landing Systems Canada Inc./ Safran Systèmes d'Atterrissage Canada Inc. Modular actuator with snubbing arrangement
US20220228640A1 (en) * 2019-05-31 2022-07-21 Hydra Dyne Technology Inc. Stroke cushioning in piston and cylinder devices
US11067104B1 (en) * 2020-11-16 2021-07-20 Caterpillar Inc. Integrated cylinder piston and bearing as a hydraulic cushion
US11319972B1 (en) * 2021-05-11 2022-05-03 Caterpillar Inc. Hydraulic cylinder snubbing retention arrangement

Also Published As

Publication number Publication date
IT948664B (it) 1973-06-11
CA940014A (en) 1974-01-15
FR2132013B1 (fr) 1978-02-10
GB1342548A (en) 1974-01-03
AU3775372A (en) 1973-07-12
DE2214032A1 (de) 1972-10-12
JPS5521208B1 (fr) 1980-06-07
FR2132013A1 (fr) 1972-11-17
AU460377B2 (en) 1975-04-24
SE374949B (fr) 1975-03-24
BE779391A (fr) 1972-08-16

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Legal Events

Date Code Title Description
AS Assignment

Owner name: CATERPILLAR INC., A CORP. OF DE.,ILLINOIS

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

Effective date: 19860515

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