US3742817A - Hydraulic lifting jacks - Google Patents

Hydraulic lifting jacks Download PDF

Info

Publication number
US3742817A
US3742817A US00141146A US3742817DA US3742817A US 3742817 A US3742817 A US 3742817A US 00141146 A US00141146 A US 00141146A US 3742817D A US3742817D A US 3742817DA US 3742817 A US3742817 A US 3742817A
Authority
US
United States
Prior art keywords
valve
ram
head
cylinder
fluid
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
US00141146A
Other languages
English (en)
Inventor
J Wenzel
H Rieschel
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.)
Freudenberger Winden und Hebez
Original Assignee
Freudenberger Winden und Hebez
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Freudenberger Winden und Hebez filed Critical Freudenberger Winden und Hebez
Application granted granted Critical
Publication of US3742817A publication Critical patent/US3742817A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F3/00—Devices, e.g. jacks, adapted for uninterrupted lifting of loads
    • B66F3/24—Devices, e.g. jacks, adapted for uninterrupted lifting of loads fluid-pressure operated
    • B66F3/25—Constructional features
    • B66F3/42—Constructional features with self-contained pumps, e.g. actuated by hand

Definitions

  • a hydraulically operated telescopic lifting jack comprises a piston carrying a ram-head which houses a nonreturn valve, a pressure relief valve and a fluid-release valve.
  • the fluid release valve includes a slide member carrying a valve member and mounted in a guide. A portion of the slide member is of reduced diameter in relation to the guide and defines therewith a chamber which communicates with a fluid feed connection.
  • HYDRAULIC LIFTING JACKS BACKGROUNIh OF THE INVENTION and distribution equipment is connected by two pressure lines to each of the four jacks with the aid of hydraulic quick-release couplings. While such an arrangement allows one-man operation, this applies only to the actions of lifting, holding and lowering, and not to the diverse operations of attaching the load to the jacks themselves and releasing it from them. These operations have to be carried out individually at each load attachment point and presuppose that each jack can be extended and retracted independently of the others and hence also independently of a central distribution system.
  • An object of the invention is to provide a hydraulic telescopic jack having a ram-head which can be supplied with pressure fluid, and hence moved, by the use of only two pressure lines from a central installation, its movements can be both purely hydraulically remotecontrolled and manually controlled and it can maintain the position in which it is set for as long as desired, even while under load and disconnected from the central installation.
  • a hydraulically-operated telescopic lifting jack a cylinder, a piston slidable within the cylinder, a ram-head carried by the piston, a first connection for hydraulic fluid, means defining a path for hydraulic fluid through the ram-head between said first connection and said cylinder, valve means mounted on said ram-head and controlling the flow of hydraulic fluid along said path, said valve means including a non-return valve, an overpressure valve, and a lowering valve, said lowering valve comprising means defining a guide in said ramhead, a slide member mounted in said guide, a portion of said slide member being of reduced diameter in relation to said guide to define piston means,and said portion defining with said guide a chamber,-a second connection for hydraulic fluid, and means defining a passage extending between said chamber and said second connection.
  • a hydraulically operated telescopic lifting jack a cylinder, a piston slidable within the cylinder, first and second feed connections for hydraulic fluid, means defining a fluid path between said first feed connection and said cylinder, a non-return valve in said path permitting flow of fluid into said cylinder, a pressure-relief valve controlling the maximum pressure of fluid flowing along said path, a fluid-release valve for releasing fluid from said cylinder and comprising cylinder means, piston means slidable in said cylinder means, and a valve member rigid with said piston means, and means defining a fluid path between said second connection and said cylinder means, so that fluid can be fed into said cylinder means to move said piston means in a sense to open said valve member.
  • the ram-head is secured by means of pegs or other connecting members in a recess in the part that is to be lifted, pressure fluid fed from a pump is forced into the cylinder from a central distribution system through a Lift" control valve. Flowback of the fluid thus pumped in is prevented by the non-return valve as soon as the pressure in the feed line is removed, so that the ram-head is hydraulically locked at the level to which it has been raised and stays there.
  • a pre-control valve that can be closed at will and which is generally open.
  • this pre-control valve is closed, the feed line then being brought under pressure from distribution system through the Lift control valve.
  • the jack can be extended slowly and very precisely, as required. This procedure can be carried out individually at each of the load lifting points with each of the jacks positioned thereat. Once all the jacks have been adjusted, the control valve is returned to its closed position and the precontrol valves are opened once more; the installation is then in working order, ready to lift the load and to hold, transfer or set it down as required.
  • the pre-control valve is a three-way valve, which connects either the feed-line connection or the distributionsystem connection to the cylinder or to a passage in communication therewith.
  • the jack it is possible for the jack to be manually lowered, by opening the lowering valve, even when the feed line is under pressure.
  • the pressure-carrying feed line is cut off by operation of the pre-control valve; the ram will not continue to move out.
  • the jack can be lowered even while the feed line is still full.
  • FIG. I is a longitudinal section of a jack in accordance with the invention.
  • FIG. 2 is a fragmentary section through a modified form of the jack shown-in FIG. 1, and shows a block diagram of a central distribution system.
  • the jack comprises a lifting ram having a cylinder 1 which is inserted in a supporting foot (not shown) and a hollow piston 2 which is movable along longitudinal guides in the cylinder 1.
  • a non-return valve 4 in the form of spring-loaded ball valve
  • an overpressure valve 5 in the form of a spring-loaded conical valve
  • a lowering valve 6 a pre-control valve 7.
  • the non-return and overpressure valves which lie co-axially one behind the other and are joined together by a passage 81, are housed within a slide member 8 of the lowering valve 6, with the non-return valve 4 inside the head 88 of the member 8 and the overpressure valve 5 nearer to the tail portion 89 thereof.
  • the passage 81 is in communication, through a radial opening 82, with a chamber 9, which accommodates a restoring spring of the lowering valve 6 and is in communication, through a passage 31, in the ram-head 3, with the interior of the hollow piston and the cylinder.
  • the tail end portion 89 of the slide member 8 that is to say the end portion of the slide member 8 remote from its head 88, is reduced in diameter and made leakproof by packing rings 83 and 84.
  • the tail end portion 89 of the slide member 8 projects out of the ram-head and has its end face bearing against a cam 11, which is mounted in a bifurcation 32 of the ram-head for pivotal movement about a pin 12, under the action of a hand lever 13.
  • the slide member 8 forms three chambers in the ramhead 3, namely: a central chamber 9 a chamber 14 surrounding the reduced-diameter tail end portion 89, in which the shoulder of the reduced-diameter portion forms a ring-shaped plunger face 86, and which communicates with the atmosphere through a passage 33 in the ram-head 3; and a chamber 15 which contains the head 88 of the slide member 8 and has an opening 34, leading to-the exterior.
  • a casing 77 of the pre-control valve 7 mounted on the ram-head 3, over the opening 34 in the chamber 15, is a casing 77 of the pre-control valve 7, the spindle 71 of which can be moved axially in a screwthread 73 by means of a handwheel 72, so that a conical valve-member can close or open a passage 74 which provides communication between the opening 34 and a connection 75 for a pressure feed line P.
  • the chamber 14 communicates, via a passage 33 with a connection 76 for a pipe R.
  • a central distribution system ST incorporates two pumps PU connected in parallel but independent of each other, which feed four hydraulic only one shown jacks.
  • the pressure connections of both pumps are branched via distribution valves STV to serve two jacks each.
  • the four jacks being applied at any moment to a load, the two opposite each other at one end of the load are served by one pump, the same applying to the pair of jacks at the other end of the load.
  • the nonreturn valve 4 can still be relied on to shut off the fluid contained in the cylinder and piston space, so that the jack will still hold its load. It is therefore possible for the jack, when under full load, to be separated from the hydraulic system by two quick-release couplings, SK, in the two pipes P and R, so as to enable the same distribution system, ST for instance, to be used in conjunction with a different set of four jacks for lifting a second container or other load.
  • the pump PU driven by a motor or internal-combustion engine M for example, drives fluid under pressure from a tank T through the feed pipe P and the normally open pre-control valve 7, into the chamber 15 in the ram-head 3. From the chamber 15, the lowering valve 6 being closed, the fluid overcomes the opposition of the non-return valve 4 and flows along the passage 81 and through the radial opening 82 into the central chamber 9, whence it passes by way of the passage 31 into the cylinder 1.
  • the hollow piston 2 rises under the pressure exerted on its end face for as long as the valve STV remains in its Lift position, or until a piston ring 21 abuts an inner shoulder 101 of a cylinder collar 102.
  • the overpressure valve 5 at the rear of the passage 81 in the tail end portion 89 of the slide member 8 opens and the fluid fed in flows through a radial opening 87 behind a conical valve member 57 of the valve 5 into the rear chamber 14 and from there through the passage 33 and the pipe R, attached to the connection 76, returns to the tank T.
  • the distribution valve STV is moved to a Lower position, the fluid fed by the pump PU then being driven, through the pipe R and the passage 33 into the chamber 14, where the pressure of the fluid acts on the ring-shaped plunger face 86, so that the slide member 8 is moved to the left (as viewed in the Figures).
  • This movement opens the lowering valve 6 and the fluid in the cylinder and piston space is forced by the loaded piston 2 through the chamber 15 and the passage 74 back into the pipe P through which it passes to the tank T.
  • the pre-control valve 7 is first closed by means of the handwheel 72.
  • the distribution valve STV in the distribution system ST is moved to its Lift" position, so that fluid is delivered under pressure, by way of the pipe P, at the now closed pre-control valve 7.
  • the passage 74 is opened to a certain extent so that pressure fluid is fed as described previously into the cylinder space and the piston 2 rises. This upward movement can be stopped by closing the valve 7, whatever the position of the piston, and the piston is then hydraulically locked in that position.
  • the distribution valve STV is once more moved to its central position, whereupon the pre-control valve 7 is opened to its full extent.
  • the pre-control valve 7 connects the opening 34 in the chamber 15 in the ram-head casing 3 either to the pipe P or to the pipe R, the path to the other pipe being closed in each case.
  • the invention is not limited to the two practical examples illustrated and described.
  • the construction and arrangement of the various valves may be different although the coaxial arrangement of the valves is preferable, because it results in a particularly small ram-head constructionand is specially suitable for the use of a normal hydraulic pit prop, which merely requires the addition of the pre-control valve, while the tail end portion of the slide member of the lowering valve must be reduced in diameter so as to form a ringshaped plunger face.
  • the pre-control valve need not necessarily be mounted in or on the ram-head, provided it be hydraulically connected to the feed aperture thereof.
  • a hydraulically-operated telescopic lifting jack a cylinder, a piston slidable within the cylinder, a ram-head carried by the piston, a first connection for hydraulic fluid, means defining a path for hydraulic fluid through the ram-head between said first connection and said cylinder, valve means mounted on said ram-head and controlling the flow of hydraulic fluid along said path, sai valve means including a non-return valve, an overpressure valve, and a lowering valve, said lowering valve comprising: means defining a guide in said ram-head, and a slide member mounted in said guide, a portion of said slide member being of reduced diameter in relation to said guide to define piston means, and said portion defining with said guide a chamber, a second connection for hydraulic fluid, and means defining a passage extending between said chamber and said second connection.
  • a jack as claimed in claim ll comprising: a pre-control valve, which can be opened at will, carried by said ram-head beyond said first connection.
  • a jack as claimed in claim 2 comprising means defining a further chamber in said ram-head, said further chamber housing said non-return valve and said lowering valve, and wherein said precontrol valve is a three-way valve and selectively connects either one of said first and second connections to said further chamber.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
  • Actuator (AREA)
  • Types And Forms Of Lifts (AREA)
  • Mechanically-Actuated Valves (AREA)
US00141146A 1970-05-08 1971-05-07 Hydraulic lifting jacks Expired - Lifetime US3742817A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2022514A DE2022514C3 (de) 1970-05-08 1970-05-08 Hydraulisch betätigter Hebebock

Publications (1)

Publication Number Publication Date
US3742817A true US3742817A (en) 1973-07-03

Family

ID=5770580

Family Applications (1)

Application Number Title Priority Date Filing Date
US00141146A Expired - Lifetime US3742817A (en) 1970-05-08 1971-05-07 Hydraulic lifting jacks

Country Status (4)

Country Link
US (1) US3742817A (enExample)
DE (1) DE2022514C3 (enExample)
FI (1) FI50612C (enExample)
GB (1) GB1351178A (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170158473A1 (en) * 2015-03-04 2017-06-08 Hangzhou Yinjiang Machinery Manufacture Co., Ltd. Hydraulic jack capable of quickly lifting load

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2069048B (en) * 1980-01-21 1984-06-06 Commercial Shearing Longwall jacks
SE451578B (sv) * 1984-09-19 1987-10-19 Hydraulik Konsult Yngve Flodin Anordning av lyftredskap for lyftning av en pa ett underlag staende container
RU2162817C2 (ru) * 1999-03-26 2001-02-10 ОАО "Калужский завод транспортного машиностроения" Гидравлический домкрат

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2618929A (en) * 1949-10-24 1952-11-25 Bidin Peter Portable hydraulic jack with filling means
US2657533A (en) * 1951-03-26 1953-11-03 Borg Warner Hydraulic control system
US3134232A (en) * 1961-10-02 1964-05-26 Walker Mfg Co Jack

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2618929A (en) * 1949-10-24 1952-11-25 Bidin Peter Portable hydraulic jack with filling means
US2657533A (en) * 1951-03-26 1953-11-03 Borg Warner Hydraulic control system
US3134232A (en) * 1961-10-02 1964-05-26 Walker Mfg Co Jack

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170158473A1 (en) * 2015-03-04 2017-06-08 Hangzhou Yinjiang Machinery Manufacture Co., Ltd. Hydraulic jack capable of quickly lifting load
US10654696B2 (en) * 2015-03-04 2020-05-19 Hangzhou Yingjiang Machinery Manufacture Co., Ltd. Hydraulic jack capable of quickly lifting load

Also Published As

Publication number Publication date
DE2022514B2 (de) 1973-07-05
FI50612B (enExample) 1976-02-02
GB1351178A (en) 1974-04-24
DE2022514A1 (de) 1972-01-13
FI50612C (fi) 1976-05-10
DE2022514C3 (de) 1974-02-07

Similar Documents

Publication Publication Date Title
US4154262A (en) Hydraulic control system
US4624445A (en) Lockout valve
US3868821A (en) Automatic pump control system
US4129987A (en) Hydraulic control system
GB919714A (en) Hydraulic control system for a fluid actuated motor
US3717995A (en) Hydraulic flotation for implement header
US3787147A (en) Two-stage air-hydraulic booster
US3665810A (en) Differential pressure holding valve
US3604313A (en) Hydraulic power circuit with rapid lowering provisions
US3654833A (en) Hydraulic control circuit
US3987703A (en) Combined restrictor and dead engine lowering valve
US4102250A (en) Load check and bypass valve
US3742817A (en) Hydraulic lifting jacks
US4006667A (en) Hydraulic control system for load supporting hydraulic motors
US4023650A (en) Hydraulic systems for two speed lifting
US4165675A (en) Load check valve cylinder mounted
US4145957A (en) Pilot-operated valve structure
EP2909484B1 (en) System preventing pressured oil leakage to cylinder line in control valve systems with flow divider
US4466336A (en) Control valve for hydraulic motor apparatus
US3811363A (en) Priority system for series-type hydraulic circuits
US4362089A (en) Valve system
US4955461A (en) Valve system for preventing uncontrolled descent in fork lift trucks
JPS5836203B2 (ja) リユウタイセイギヨカイロ
US4286502A (en) Hydraulic load lifting system with automatic blocking valve
US4320691A (en) Hydraulic load lifting system with hydraulic surcharge to make up valve pilot lines