EP0224914B1 - Hydraulische Kolbenzylindereinheit mit einer mechanischen Sicherheitsvorrichtung, insbesondere für Kraftfahrzeughebebühnen mit Scheren - Google Patents

Hydraulische Kolbenzylindereinheit mit einer mechanischen Sicherheitsvorrichtung, insbesondere für Kraftfahrzeughebebühnen mit Scheren Download PDF

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Publication number
EP0224914B1
EP0224914B1 EP86116771A EP86116771A EP0224914B1 EP 0224914 B1 EP0224914 B1 EP 0224914B1 EP 86116771 A EP86116771 A EP 86116771A EP 86116771 A EP86116771 A EP 86116771A EP 0224914 B1 EP0224914 B1 EP 0224914B1
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EP
European Patent Office
Prior art keywords
cylinder
piston
piston unit
stop member
rod
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
EP86116771A
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English (en)
French (fr)
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EP0224914A1 (de
Inventor
Eride Rossato
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Individual
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Individual
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Publication date
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Publication of EP0224914A1 publication Critical patent/EP0224914A1/de
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Publication of EP0224914B1 publication Critical patent/EP0224914B1/de
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
    • 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
    • F15B15/26—Locking mechanisms
    • F15B15/261—Locking mechanisms using positive interengagement, e.g. balls and grooves, for locking in the end positions
    • 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
    • B66F3/30—Constructional features with positive brakes or locks
    • 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
    • B66F7/00—Lifting frames, e.g. for lifting vehicles; Platform lifts
    • B66F7/06—Lifting frames, e.g. for lifting vehicles; Platform lifts with platforms supported by levers for vertical movement
    • B66F7/0641—Single levers, e.g. parallel links
    • 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
    • B66F7/00—Lifting frames, e.g. for lifting vehicles; Platform lifts
    • B66F7/06—Lifting frames, e.g. for lifting vehicles; Platform lifts with platforms supported by levers for vertical movement
    • B66F7/08—Lifting frames, e.g. for lifting vehicles; Platform lifts with platforms supported by levers for vertical movement hydraulically or pneumatically operated

Definitions

  • This invention relates to a hydraulic cylinder-piston unit provided with a mechanical safety device, particularly for motor vehicle lifts of the pantograph type.
  • Motor vehicle lifts of the pantograph type are known. They generally comprises a pair of runways and cylinder-piston units which raise said runways, on which the vehicle to be lifted has been previously positioned.
  • Known safety systems generally consist of racks engaged by pawl assemblies which allow the racks to move freely relative to them during the raising of the lift, but prevent their opposite movement, thus ensuring stability of the attained configuration.
  • US-A-2 540 578 discloses a hydraulic internal locking jack comprising a cylinder, a hollow piston operable in the cylinder and emerging from one end closure member of said cylinder, a toothed post fixed to the other end closure member, and a releasable locking means preventing accidential retraction of the piston.
  • the locking means includes a spring actuated pawl assembly associated with the piston and cooperating with the teeth of the post. The pawls are slidingly received in a cage which is fixed to the piston.
  • a drawback of this hydraulic locking jack consists in that it requires a further device actuable by hand, for releasing the pawl assembly from the teeth of the post. This is particularly disadvantageous when the hydraulic jacks are placed, due to constructive reasons, in positions not well accessible and when they, if more than one, must actuated simultaneously; this happens, in particular, in the case of hydraulic jacks for lifting ramps.
  • An object of the invention is to obviate these drawbacks by providing a double-acting hydraulic cylinder-piston unit with an associated mechanical safety device which is without bulk and requires no special additional installation work.
  • a furthere object of the invention is to provide a hydraulic cylinder-piston unit with an associated mechanical safety device which for disengaging this latter uses the actual hydraulic feed circuit of the cylinder-piston unit.
  • a hydraulic cylinder-piston unit provided with a mechanical safety device, particularly for motor vehicle lifts of pantograph type and comprising a cylinder having a closed endpiece and in which there slides a piston provided with a hollow rod emerging from the opposite endpiece of said cylinder, said rod housing in its interior a second toothed rod which is fixed at one end to the closed endpiece of said cylinder, is movable axially relative to said hollow rod by means of said piston, and cooperates with a pawl assembly housed in the piston and comprising at least a stop member which during the elongation state of the cylinder-piston unit moves relative to the toothed rod by yielding elastically in its passage from one tooth to the next, whereas during the retraction state it engages in the facing notch defined by two successive teeth to thus form the mechanical safety stop, characterised in that the pawl assembly comprises for each stop member a plunger communicating with the rod end chamber of the cylinder and acting, when in the presence of slight
  • the hydraulic cylinder-piston unit comprises a cylinder 1 closed lowerly by a solid endpiece 2, and closed upperly by and endpiece 3 comprising a central circular hole for the oil-tight passage of a rod 4.
  • the endpiece 2 When used in a lift (see Figure 1), the endpiece 2 is provided with a lug for its connection and hinging to a lower longitudinal member 6 of the lift, and the outer end of the rod 4 is provided with a head 5 for its connection and hinging to an upright 8.
  • the rod 4 which is hollow, is connected to a piston 9 slidable in an oil-tight manner inside the cylinder 1.
  • a further rod 10 which comprises a plurality of equidistant circumferential notches 11 having a profile such as to form a sawtooth pattern, as can be seen from Figure 2.
  • the rod 10 is mobile axially relative to the rod 4, and is fixed at one end to the endpiece 2 of the cylinder 1.
  • the rod 10 also traverses the piston 9, without any need for sealing.
  • an aperture 12 for the passage of oil into and from the cylinder 1
  • an aperture 13 is provided in the lateral surface of the cylinder 1 in proximity to the endpiece 3.
  • the piston 9 consists substantially of a pair of annular flanges indicated overall by 14 and 14', and joined together by screws.
  • These flanges have an outer profile which is complementary to the profile of a rubber gasket 15 which seals the piston 9 against the inner lateral surface of the cylinder 1.
  • the upper flange 14, which is screwed to the rod 4, comprises three radial recesses 16 disposed at 120° apart, in which stop blocks 17 can slide.
  • each stop block 17 has its front profile curved to correspond to the facing surface of the toothed rod 10, and comprises two cylindrical cavities 18 for housing small helical springs 19 interposed between said block 17 and the shoulder 20 which delimits the rear of the corresponding recess 16. It also comprises an inner cavity having an inclined surface 21 facing upwards in Figure 3. On said inclined surface there rests the eccentric stem 22 of a plunger 23 mobile axially in a sealed manner within a corresponding cylindrical cavity 24 -formed in the upper flange 14 and communicating with the interior of the cylinder 1.
  • the three cylindrical cavities 24 are also disposed at 120° apart.
  • the operation of the hydrolic cylinder-piston unit according to the invention is as follows : when in the rest state (minimum elongation) the piston 9 is in its lower end-of-stroke position, that cylindrical portion of the rod 10 not provided with toothing faces the three blocks 17, the three blocks 17 are urged by the respective springs 19 to adhere to the cylindrical surface of the rod 10, and the plungers 23 are raised.
  • the cylinder-piston units are firstly made to elongate slightly by normal methods in order to disengage _ the stop blocks 17 from the relative notch 11. Oil is then fed through the aperture 13. Its pressure acts initially on the plungers 23, which descend and press by way of their stem 22 against the inclined surface 21 of the corresponding stop block 17. By virtue of this, the blocks 17 are withdrawn into the piston 9 along the respective recesses 16, so that they no longer interfere with the toothed rod 10. By continuously feeding oil through the aperture 13 with simultaneouse discharge of other oil through the aperture 12, the piston 9 is made to descend, with the toothed rod 10, which is no longer hindered by the stop blocks 17, simultaneously retracting into the rod 4.
  • the cylinder-piston unit according to the invention is used advantageously in pantograph lifts of the type shown diagrammatically in Figure 1.
  • the stop blocks are effectively in their disengaged state before lowering the lift, so as to prevent any possible dangerous consequences deriving from unbalanced loads.
  • a member such as a microswitch 25, which enables the lift to be lowered only if activated by the block when in its rear end-of-travel position.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Current-Collector Devices For Electrically Propelled Vehicles (AREA)
  • Braking Systems And Boosters (AREA)
  • Vehicle Cleaning, Maintenance, Repair, Refitting, And Outriggers (AREA)
  • Types And Forms Of Lifts (AREA)
  • Hydraulic Motors (AREA)

Claims (5)

1. Hydraulische Zylinder-Kolben-Einheit, welcher mit einer mechanischen Sicherheitsvorrichtung versehen ist, insbesondere für Kraftfahrzeughebebühnen mit Scheren, und welche einen Zylinder (1) aufweist, der ein geschlossenes Endstück (2) aufweist und in dem ein Kolben (9) gleitet, der mit einer vom entgegengesetzten Endstück (3) des genannten Zylinders austagenden hohlen Stange (4) versehen ist, wobei besagte Stange (4) in ihrem Inneren eine zweite, gazahnte Stange (10) enthält, welche an dem einen Ende am geschlossenen Endstück (2) des besagten Zylinders (1) befestigt ist, achsial in bezug auf die besagte hohle Stange (4) mittels des besagten Kolbens (9) bewegbar ist und mit einer Klinkenanordnung zusammenwirkt, welchen im Kolben (9) untergebracht ist und mindestens ein Anschlagstück (17) aufweist, welches sich während des Verlängerungszustandes der Zylinder-Kolben-Einheit in Bezug auf die gezahnte Stange (10) durch elastisches Fließen bei seinem Weg von einem Zahn zum nächsten bewegt, wogegen es während des Zurückziehungszustandes in die gegenüberliegende Kerbe (11), welche durch zwei aufeinanderfolgende Zähne definiert ist, eingreift, um so den mechanischen Sicherheitsanschlag zu bilden, dadurch gekennzeichnet, daß die Klinkenanordnung für jedes Anschlagstück einen Preßkolben (23) aufweist, welcher mit der Stangenendkammer des Zylinders (1) kommuniziert und im Fall des Vorhandenseins eines geringen Druckes in besagter Kammer im Sinn des Zurückziehens des entsprechenden Anschlagstückes in den Kolben (9) in Aktion tritt.
2. Hydraulische Zylinder-Kolben-Einheit nach Anspruch 1, dadurch gekennzeichnet, daß der Preßkolben (23) mit einem Schaft (22) versehen ist, welcher mit einer geneigten Fläche (21) zusammenwirkt, welche im Anschlagstück (17) vorgesehen ist, um, als ein Ergebnis seiner Achsialbewegung, besagtes Anschlagstück (17) zu veranlassen, in den Kolben (9) zurückzutreten.
3. Hydraulische Zylinder-Kolben-Einheit nach Anspruch 1, dadurch gekennzeichnet, daß jedes Anschlagstück (17) mit einem Sensor (25) versehen ist, welcher dessen deaktivierten Status aufspürt.
4. Hydraulische Zylinder-Kolben-Einheit nach Anspruch 3, gekennzeichnet durch das Vorhandensein eines Sensors (25), welcher aufspürt, wenn jedes Anschlagstück (17) seine Wegende-Position in einem korrespondierenden Führungsrücksprung (16), welcher im Kolben (9) vorgesehen ist, erreicht hat.
5. Hydraulische Zylinder-Kolben-Einheit nach Anspruch 4, dadurch gekennzeichnet, daß der Sensor (25) aus einem Mikroschalter besteht, welcher durch das entsprechende Anschlagstück (17) aktiviert ist, sobald dieses seine Wegende-Position erreicht hat.
EP86116771A 1985-12-05 1986-12-02 Hydraulische Kolbenzylindereinheit mit einer mechanischen Sicherheitsvorrichtung, insbesondere für Kraftfahrzeughebebühnen mit Scheren Expired - Lifetime EP0224914B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT8584159A IT1214977B (it) 1985-12-05 1985-12-05 Martinetto fluodinamico provvistodi dispositivo meccanico disicurezza, particolarmente per ponti sollevatori a pantografo per autoveicoli.
IT8415985 1985-12-05

Publications (2)

Publication Number Publication Date
EP0224914A1 EP0224914A1 (de) 1987-06-10
EP0224914B1 true EP0224914B1 (de) 1990-03-07

Family

ID=11324937

Family Applications (2)

Application Number Title Priority Date Filing Date
EP86116771A Expired - Lifetime EP0224914B1 (de) 1985-12-05 1986-12-02 Hydraulische Kolbenzylindereinheit mit einer mechanischen Sicherheitsvorrichtung, insbesondere für Kraftfahrzeughebebühnen mit Scheren
EP87900094A Expired - Lifetime EP0293368B1 (de) 1985-12-05 1986-12-02 Hydraulische kolben-zylindereinheit mit einer mechanischen sicherheitsvorrichtung, insbesondere für kraftfahrzeughebebühnen mit scheren

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP87900094A Expired - Lifetime EP0293368B1 (de) 1985-12-05 1986-12-02 Hydraulische kolben-zylindereinheit mit einer mechanischen sicherheitsvorrichtung, insbesondere für kraftfahrzeughebebühnen mit scheren

Country Status (10)

Country Link
EP (2) EP0224914B1 (de)
AT (1) ATE53896T1 (de)
AU (1) AU604673B2 (de)
CA (1) CA1302206C (de)
DE (1) DE3670888D1 (de)
ES (1) ES2013593B3 (de)
GR (1) GR3000525T3 (de)
IL (1) IL80838A (de)
IT (1) IT1214977B (de)
WO (1) WO1987003655A1 (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1237417B (it) * 1989-01-18 1993-06-01 Eride Rossato Dispositivo sollevatore di autoveicoli, particolarmente per carrozzerie.
IT1282522B1 (it) * 1995-05-19 1998-03-23 Eride Rossato Ponte sollevatore a pantografo per autoveicoli
AU701019B2 (en) * 1995-11-14 1999-01-21 Hilland Pty Ltd Trading As Edmo Equipment Vehicle jack and stand

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE25334E (en) * 1963-02-19 Piston cylinder apparatus
DE211847C (de) *
GB211412A (en) * 1923-07-23 1924-02-21 Charles Frederick Webb Improvements relating to pneumatic lifting jacks
GB490886A (en) * 1936-11-27 1938-08-23 Servo Frein Dewandre Sa Control device with pre-determined successive positions
US2540578A (en) * 1945-09-27 1951-02-06 Lockheed Aircraft Corp Hydraulic internal locking jack
FR952142A (fr) * 1946-08-15 1949-11-09 C V Fabriek Voor Auto En Machb Système de blocage et de freinage
US3020888A (en) * 1959-07-02 1962-02-13 Gen Electric Linear motion-producing device with lock
US3104593A (en) * 1960-12-28 1963-09-24 Regent Jack Mfg Co Inc Fluid actuators
US3180234A (en) * 1963-07-25 1965-04-27 Jarry Hydraulics Ltd Dual-position lockable actuator
AU557669B2 (en) * 1981-08-04 1987-01-08 Alfarm Australia Limited Hydraulic cylinder with locking mechanism
IL67722A0 (en) * 1982-02-05 1983-05-15 Plessey Overseas Container with memory
AU548927B2 (en) * 1982-06-11 1986-01-09 Terrance Arthur Baroody Tubing tee joint

Also Published As

Publication number Publication date
AU6831387A (en) 1987-06-30
ES2013593B3 (es) 1990-05-16
IL80838A (en) 1991-01-31
AU604673B2 (en) 1991-01-03
EP0293368B1 (de) 1990-05-02
EP0224914A1 (de) 1987-06-10
IL80838A0 (en) 1987-03-31
IT1214977B (it) 1990-01-31
ATE53896T1 (de) 1990-06-15
EP0293368A1 (de) 1988-12-07
GR3000525T3 (en) 1991-07-31
WO1987003655A1 (en) 1987-06-18
CA1302206C (en) 1992-06-02
IT8584159A0 (it) 1985-12-05
DE3670888D1 (de) 1990-06-07

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