EP0055697B1 - Système hydraulique comportant un piston téléscopique à double action pour le mouvement de charges dans des conditions instables - Google Patents
Système hydraulique comportant un piston téléscopique à double action pour le mouvement de charges dans des conditions instables Download PDFInfo
- Publication number
- EP0055697B1 EP0055697B1 EP81830251A EP81830251A EP0055697B1 EP 0055697 B1 EP0055697 B1 EP 0055697B1 EP 81830251 A EP81830251 A EP 81830251A EP 81830251 A EP81830251 A EP 81830251A EP 0055697 B1 EP0055697 B1 EP 0055697B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- passage
- load
- piston
- serving
- double
- 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
Links
Images
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
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/16—Characterised by the construction of the motor unit of the straight-cylinder type of the telescopic type
Definitions
- the invention relates to a hydraulic actuating system comprising a telescopic cylinder and piston assembly for displacing a heavy load about a pivot axis, whereby the center of gravity often moves overcenter, and comprising a control apparatus for supplying pressurized fluid to and exhausting fluid from the telescopic assembly; said telescopic assembly including a plurality of stages, the last stage thereof having a double-acting piston carrying an output rod provided with a first passage serving to supply pressurized fluid to the head end of the telescopic assembly for expanding the latter and also serving as an exhaust passage and provided with a second fluid passage serving to supply pressurized fluid to the rod end of the last stage and also serving as an exhaust passage.
- An operation such as lifting of the movable carriage of a lorry is normally carried out with simple action hydraulic telescopic piston.
- Said known hydraulic actuating system is provided with a cushioning sleeve slidable positioned in the cylinder and on the piston head.
- the inner surface of said sleeve is provided with two pairs of diametrically opposed columns of recesses arranged longitudinally of the sleeve. Said recesses decrease in depth and length from one end of the sleeve toward the other end thereof.
- a valve assembly for decreasing the speed of cylinder contraction is located in the first passage and includes an openended flow control valve slidably mounted in the passage and formed with a plurality of elongated slots.
- a spring biases the flow control valve whereby the slots are located outside of the associated passage when the cylinder is expanded.
- pressurized fluid is pumped through both passages and consequently both ends of said piston head are admitted.
- the present invention is based on the technical task of how to provide a cushioning effect just at the point of unstable equilibrium in a much more simple manner than in the prior art.
- the double-acting piston may be in a direct sliding contact with the inner surface of the stage next to the last, and no cushioning sleeve or the like is necessary in order to balance the pull of the load just past the point of unstable equilibrium.
- the system of the invention is very compact and behaves, forthe first half of the movement up to the point just before inversion of the driving force, as a simple-action telescope, whereas in the second half of the movement it behaves as a double-action piston which by generating a controlled counter-pressure, controls the movement of the load by generating a retaining or braking force, just near to the point of unstable equilibrium (PMS).
- PMS point of unstable equilibrium
- FIG. 1a an ideal load driven by a piston 1 and fixed at point C by a hinge is illustrated.
- the force F is such as to oppose the weight force P of the load, in fact it exceeds P and moves the load so as to bring about its displacement.
- FIG. 1 b illustrates the position when the load has reached the point of unstable equilibrium (PMF).
- This condition of the weight force P indicated by "X”
- X passes the fixed point C of the hinge.
- the drive force F necessary for lifting, and thus for the displacement of the load must be counter balanced by a retaining force R.
- Figure 1c illustrates the retaining situation by means of the force R which keeps the load in equilibrium. It is necessary to point out that the most delicate part of the displacement is that in which the drive force F is substituted, in a controlled manner, by the retaining force R which avoids sharp movements or whatsmore falling of the load.
- FIG 2 a typical realisation of the hydraulic system of the present invention is schematically illustrated.
- the telescopic piston 1 shown has three sliding sections in the last of which is mounted a double-action piston supplied with two chambers 24 and 30 which are in fact necessary to attain the double effect.
- the simple-action sliding sections make use of the single chamber 21. These chambers are obviously utilised for the letting-in and out the compressed oil fed by means of pipeline 20.
- Figure 2 illustrates the hydraulic system in its initial position in which the sliding sections are all closed, and the oil is in a rest condition in all the chambers.
- pipelines 25 and 20 constitute the forward and return of the oil's counterpressure respectively ( Figure 5).
- Figure 7 illustrates the telescopic piston on returning to its rest position, when the oil in chamber 21 is withdrawn through pipeline 20.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Actuator (AREA)
Claims (3)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT50493/80A IT1128739B (it) | 1980-12-31 | 1980-12-31 | Dispositivo idraulico con pistone telescopico a doppio effetto per il ribaltamento di carichi in condizioni di instabilita' |
IT5049380 | 1980-12-31 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0055697A1 EP0055697A1 (fr) | 1982-07-07 |
EP0055697B1 true EP0055697B1 (fr) | 1987-07-08 |
Family
ID=11273078
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP81830251A Expired EP0055697B1 (fr) | 1980-12-31 | 1981-12-22 | Système hydraulique comportant un piston téléscopique à double action pour le mouvement de charges dans des conditions instables |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0055697B1 (fr) |
DE (1) | DE3176301D1 (fr) |
IT (1) | IT1128739B (fr) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8815785D0 (en) * | 1988-07-02 | 1988-08-10 | British Petroleum Co Plc | Soft-landing device |
DE102005011630A1 (de) * | 2005-03-14 | 2006-09-21 | Franz Xaver Meiller Fahrzeug- Und Maschinenfabrik - Gmbh & Co Kg | Hubgerät für Wechselbehälter auf einem Lastentransportfahrzeug, insbesondere auf einem Abrollkipperfahrzeug oder auf einem Absetzkipperfahrzeug |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2897791A (en) * | 1957-01-24 | 1959-08-04 | Int Harvester Co | Cushioning means for hydraulic actuating means |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE929148C (de) * | 1942-08-05 | 1955-06-20 | Meiller Fahrzeuge | Hydraulisch betaetigte Hub-, Kipp- und Rueckholpresse, insbesondere fuer Kraftfahrzeuge |
US2517153A (en) * | 1946-08-16 | 1950-08-01 | Gar Wood Ind Inc | Telescopic power down hoist |
US3415169A (en) * | 1966-06-10 | 1968-12-10 | Euclid | Hydraulic cylinder |
US3603207A (en) * | 1969-05-26 | 1971-09-07 | Koehring Co | Multiple-cylinder telescopic actuator |
FR2129936B1 (fr) * | 1971-03-17 | 1976-02-06 | Benalu Fr | |
US3956970A (en) * | 1971-11-02 | 1976-05-18 | Montanhydraulik Gmbh & Co. Kg | Multiple stage hydraulic telescopic cylinder device |
GB1526563A (en) * | 1977-06-17 | 1978-09-27 | Davy Loewy Ltd | Fluid operable piston-cylinder device |
-
1980
- 1980-12-31 IT IT50493/80A patent/IT1128739B/it active
-
1981
- 1981-12-22 EP EP81830251A patent/EP0055697B1/fr not_active Expired
- 1981-12-22 DE DE8181830251T patent/DE3176301D1/de not_active Expired
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2897791A (en) * | 1957-01-24 | 1959-08-04 | Int Harvester Co | Cushioning means for hydraulic actuating means |
Also Published As
Publication number | Publication date |
---|---|
DE3176301D1 (en) | 1987-08-13 |
IT8050493A0 (it) | 1980-12-31 |
IT1128739B (it) | 1986-06-04 |
EP0055697A1 (fr) | 1982-07-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4289442A (en) | Boom lift load relief | |
US2830788A (en) | Pushing and pulling apparatus | |
US2595307A (en) | Portable well servicing rig | |
US2911111A (en) | Mobile hydraulic crane | |
US7703616B2 (en) | Telescopable sliding beam | |
US7458308B2 (en) | Multistaged telescope boom | |
US5613418A (en) | Multiple-stage hydraulic cylinder | |
US3018902A (en) | Hydraulic crane | |
US2968410A (en) | Towers | |
US2883003A (en) | Mast lift trucks | |
EP0055697B1 (fr) | Système hydraulique comportant un piston téléscopique à double action pour le mouvement de charges dans des conditions instables | |
JP2009030652A (ja) | 多段伸縮駆動装置 | |
US2906413A (en) | Hydraulic crane | |
US20190321968A1 (en) | Motor-drive assembly capable of deploying a traction force, use of the assembly for the motorized driving of an articulated arm, and associated method | |
US4344354A (en) | Valve arrangement for controlling the stroke of a telescoping prop | |
US4333634A (en) | Gripper assembly for moving drilling rigs | |
CN103057526A (zh) | 控制多个支腿同步支撑的液压系统和工程车辆 | |
GB2068330A (en) | Telescopic crane jib | |
USRE27224E (en) | Fluid feed lines | |
US2513246A (en) | Lifting jack | |
ES2042169T3 (es) | Cilindro telescopico hidraulico para basculantes de vehiculos. | |
US3029962A (en) | Bushing construction for side shift carriage | |
FI90584B (fi) | Menetelmä ja laitteet paineväliaineen johtamiseksi toimilaitteille | |
US1567203A (en) | Jack | |
JPS582919B2 (ja) | ジユウリヨウブツシヨウコウソウチ |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Designated state(s): DE FR GB NL SE |
|
17P | Request for examination filed |
Effective date: 19830221 |
|
R17P | Request for examination filed (corrected) |
Effective date: 19830107 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB NL SE |
|
REF | Corresponds to: |
Ref document number: 3176301 Country of ref document: DE Date of ref document: 19870813 |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19901109 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 19901120 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19901212 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 19901231 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19910227 Year of fee payment: 10 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Effective date: 19911222 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Effective date: 19911223 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Effective date: 19920701 |
|
NLV4 | Nl: lapsed or anulled due to non-payment of the annual fee | ||
GBPC | Gb: european patent ceased through non-payment of renewal fee | ||
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Effective date: 19920831 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Effective date: 19920901 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
EUG | Se: european patent has lapsed |
Ref document number: 81830251.5 Effective date: 19920704 |