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EP0310022A1 - Dispositif hydraulique télescopique - Google Patents

Dispositif hydraulique télescopique Download PDF

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Publication number
EP0310022A1
EP0310022A1 EP88115980A EP88115980A EP0310022A1 EP 0310022 A1 EP0310022 A1 EP 0310022A1 EP 88115980 A EP88115980 A EP 88115980A EP 88115980 A EP88115980 A EP 88115980A EP 0310022 A1 EP0310022 A1 EP 0310022A1
Authority
EP
European Patent Office
Prior art keywords
piston
telescopic device
connection line
valve
guide member
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.)
Granted
Application number
EP88115980A
Other languages
German (de)
English (en)
Other versions
EP0310022B1 (fr
Inventor
Erling Pedersen
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.)
NISAP MASKINFABRIK AS
Original Assignee
NISAP MASKINFABRIK AS
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 NISAP MASKINFABRIK AS filed Critical NISAP MASKINFABRIK AS
Publication of EP0310022A1 publication Critical patent/EP0310022A1/fr
Application granted granted Critical
Publication of EP0310022B1 publication Critical patent/EP0310022B1/fr
Expired legal-status Critical Current

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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
    • B66F3/26—Adaptations or arrangements of pistons
    • B66F3/28—Adaptations or arrangements of pistons telescopic
    • 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 present invention relates to a hydraulic telescopic device comprising several immersed pistons arranged in a main cylinder and actuated by means of a pump having an overloading valve determining the maximum pressure produced by the pump.
  • Hydraulic telescopic devices of this type are used in many different applications e.g. in connection with lifting devices in the form of tipping waggons, lifting tables, highlifting lift trucks, so-called highlifters, etc.
  • a piston area is provided which is different from the piston areas of the other steps.
  • the overloading valve which is connected with the pump determines the maximum pressure supplied by the pump. Together with the piston area this maximum pressure determines the lifting force which the telescopic device may exert in connection with the associated lifting device.
  • the greatest piston is extended and secondly, the next following smaller piston is exten­ded, and so on, until the telescopic device is fully extended.
  • the associated lifting device is dimensioned for lifting e.g 1000 kg the telescopic device should thus be able to lift 1000 kg in fully extended state.
  • the force exerted by the telescopic device is a func­tion of the prevailing pressure and the area of the piston extended in the latest step. As the area of the piston extended in the latest step is smaller than that of the pistons extended in the previous steps and as the overloading valve of the pump is effective at a previously set or chosen pressure it is thus possible to exert a greater force in the preceding steps.
  • This greater force may raise the lifting device even though it is loaded with a weight substantially exceeding 1000 kg.
  • a two-step telescopic device is used and in case the ratio between the areas of the pistons is 1:2 then the telescopic device will be able to lift a 2000 kg load in the first step.
  • a heavy overloading may give rise to the breakdown of the lifting device.
  • the overloading valve may be set to open at a substantially lower pressure.
  • a hy­draulic telescopic device mentioned by way of introduction and which is characterized in that the telescopic device is provided with at least one relief device consisting of a connection line provided in a combined cylinder head and guide member and which opens into the pres­surized compartment in the cylinder which is closed by the combined cylinder head and guide member, a relief valve connected with the con­nection line and a return line leading to an oil tank and acting for the piston in said cylinder, and a cut-off member which is actuated by said piston to close the connection line at the end of the piston stro­ke.
  • telescopic device having one or more relief devices which may be adjusted to the maximum allowable pressure prevailing during the extension of a specific piston, said relief device being inactivated at the end of the stroke of said piston.
  • a pressure will also prevail inside the cylinder all the way along the outer side of the piston which pres­sure corresponds to the pressure exerted on the lower side of the pis­ton and which effects the extension of the piston.
  • the pressure pre­vailing along the outer side of the piston will actuate the relief valve via the connection line in the combined cylinder head and guide member.
  • the relief valve opens and provides for the return of the hy­draulic oil to the oil tank.
  • the cut-off member will cut off the passage which leads the hydraulic oil to the relief valve and during the following extension, if any, of one or more inner pistons, these pistons may correspondingly be connected with a relief valve which is adjusted to the pressure prevailing during the extension of such piston(s).
  • the area of such inner pistons is smaller such following relief valves or the overloading valve connected with the pump works at higher pressures thereby making it possible to obtain the dimensioned lifting capacity.
  • the relief valve is advantageously built into the combined cylinder head and guide member.
  • the oil tank is situated around the main cylinder and is extended to and is defined by the combined cylin­der head and guide member.
  • the return pipe from the relief valve placed in the combined cylinder head and guide member may open direct­ly into the oil tank.
  • the telescopic device, the associated oil tank and the pump appear as an assembly which may advantageously be manufactured without any outer pipes.
  • the pump it is possible to arrange the pump as a separate unit if desired, e.g. in connection with an electrically activated pump.
  • Fig. 1 shows a view, partly in section, of a known two-step telescopic device.
  • the telescopic device illustrated is intended for use in a highlifting lift truck of the type shown in Fig. 6.
  • the telescopic de­vice comprises a main cylinder 1, wherein the two pistons 2 and 3 are placed.
  • the largest piston 2 is intended to be extended together with the inner piston 3 in the first step.
  • the piston 2 has protruding guide blocks 5 which are in contact with the inner surface of the wall 6 in order to guide the piston 2 during its extension from the main cylinder 1.
  • a combined cylinder head and guide member 7′ is placed which on the one hand closes the cylinder 1 and on the other assists in guiding the piston 2.
  • the combined cylin­der head and guide member 7′ illustrated in Fig. 1 is manufactured in the conventional design which means that it is impossible to provide a relief device according to the invention.
  • An oil tank 8 is arranged surrounding in part the main cylinder thus providing a compact built-together unit which is especially applicable in combination with the lifting device illustrated in Fig. 6.
  • the telescoping device shown in Fig. 1 may be converted to a telescopic device according to the in­vention solely by substituting the combined cylinder head and guide member 7′ with a combined cylinder head and guide member 7 of the type illustrated in Figs. 3 or 4.
  • Fig. 1 illustrates a manually operated pump 9 which is acti­vated through a piston 10 by a combined pump rod and handle 11 (see Fig. 6).
  • the pump 9 will be used conventionally to pump hydraulic oil into the space between the wall 6 of the main cylinder 1 and the piston 2 which are thereby immersed in the hydraulic oil, and accordingly, oil under pressure is provided along the outside of the piston up to a sealing member 12 placed in the combined cylinder head and guide member 7′.
  • a valve system 13 is positioned on the one hand so as to ensure the correct function of the pump and on the other so as to provide an overloading valve ensuring a limited maximum pump pressure.
  • the oil tank may be manufactured in a different form provided as a separate tank and placed apart from the telescopic device.
  • Fig. 2 illustrates a principle outline for a telescopic device accord­ing to the invention.
  • elements in Fig. 2 and in the following figures which are identical or corresponding are denoted with references identical to those used in Fig. 1.
  • Fig. 2 shows a main cylinder 1 com­prising a hollow piston 2 and an inner piston 3.
  • Fig. 2 shows a main cylinder 1 com­prising a hollow piston 2 and an inner piston 3.
  • it is a two-step telescopic device corresponding to the one illustrated in Fig. 1.
  • the combined cylinder head and guide member 7 shown more detailed in Fig.
  • connection line (not shown here) is provided, said connection line being connected with an outer connection line 14 and opening (through a not shown mouth) in the space 15 which is produced between the cylinder 1 and the piston 2 and which is filled with pressurized hydraulic oil.
  • the connection line 14 is connected with a relief valve 17 via a cut-off member provided in the form of a change-over valve 16.
  • the relief valve 17 is connected with the oil tank 8 via by return line 18.
  • a system corresponding to the one connected with the main cylinder may be arranged at the top of the hollow piston 2 in order to provide a further connection line and a further relief valve (not shown).
  • Such construction is advantageously used when the telesco­pic device comprises more than two steps.
  • the overloading valve which is associa­ted with the pump and which is adjusted to open at the pressure corres­ponding to the maximum allowable load of the telescopic device.
  • this valve may according to the prior art be changed by means of an activat­ing knob 16′ at the end of the stroke of the piston 2 in order to cut off the connection line. In this situation the relief valve 17 will not be operative.
  • a cut-off member 19 may be positioned at the bottom of the piston 2 in the vicinity of the guide bloks 5. This cut-off member 19 is in­tended to cut off the mouth of the connection line 14 at the end of the stroke of the piston 2.
  • the connection with the relief valve 17 will be disrupted and the relief valve provided in association with the valve system 13 (not shown in Fig. 2) will then be operative.
  • cut-off members in the form of the outer change-­over valve 16 may be used as an alternative to the cut-off member 19 which is positioned inside the telescopic device itself and both al­ternatives are shown in the same figure for illustrative reasons only.
  • Fig. 3 illustrates a combined cylinder head and guide member 7 corres­ponding substantially to the one shown in Fig. 1 and which corresponds to the part included in the circle III.
  • the combined cylinder head and guide member 7 shown in Fig. 3 is provided with a relief devi­ce according to the invention. From Fig. 3 is occurs that the sealing member 12 is positioned in the combined cylinder head and guide member 7 in contact with the piston rod 20. Also a wiper 21 is provided.
  • the piston 2 is provided with guide blocks 5 which are in contact with the cylinder wall 6, and a seal ring 22 is positioned between the cylinder wall 6 and the combined cylinder head and guide member 7. Pressurized hydraulic oil will thus be provided in the space 15.
  • the relief valve 17 is positioned in the combined cylinder head and guide member 7.
  • the relief valve comprises an ad­justing screw 23 which is provided with a seal ring 24 and which via a spring 25 actuates a valve body 26 bringing it into contact with a seat 27.
  • the relief valve is connected with the pressurized compartment through a connection line 28, viz. the space 15 during the extension of the piston 2.
  • the relief valve 17 is via a return line, provided in the form of an opening 29 connected with the oil tank 8 surrounding the telescopic device.
  • Fig. 3 illustrates a cut-off member 19 consisting of a ball valve 30 which is biased by means of a spring 31 against its position for open­ing the connection line 28.
  • the ball is retained in its position by any well known means which will not be explained in detail.
  • the ball valve 30 cooperates with an actuating member 32 positioned on the upper side of guide blocks 5 and which member brings the ball 30 in contact with the valve seat 33 at the end of the piston stroke in order to cut off the connection line 28.
  • the actuating member 32 compri­ses an elastic material which compensates for manufacturing tolerances.
  • the embodiment illustrated in Fig. 4 comprises most of the parts repre­sented in the embodiment of Fig. 3 and a detailed description of this embodiment will be given only of the elements which differ from the embodiment of Fig. 3.
  • the cut-off member 19 of Fig. 4 comprises a seal ring 34 positioned in a groove 35 with a piston rod 20.
  • a recess 36 is provided in the combined cylinder head and guide member which recess is connected with the mouth 37 of the connection line 28 which mouth is connected with the pressurized space 15.
  • the upper side of the guide blocks 5 contacts a surface 38 of the combined cylinder head and guide member 7 and the seal ring 34 is placed in the recess 36 and thus cuts off the connection between the mouth 37 and the pressurized space 15.
  • Fig. 5 illustrates a combined cylinder head and guide member 7 wherein a connection line 28 is provided.
  • the connection line 28 is connected with a bore 39 and may be connected with an outer connection line 14 leading to an external relief valve, e.g. as illustrated in Fig. 2.
  • the cut-off member is positioned outside the telescopic device itself.
  • Fig. 6 illustrates a lifting device associated with a telescopic device according to the invention.
  • the lifting device may be dimensioned for a maximum allowable load, e.g. of 1000 kg.
  • the associated lifting devi­ce is provided in the form of a so-called highlifter intended to raise a pallet to a normal working height.
  • highlifter it is customary to use a two-step hydraulic telescopic device which on the one hand ensures a low constructional height and on the other, a sufficient lifting height.
  • the lifting device is supported of crotched legs 40,41 hinged to the highlifter at the support wheels 42 for the telescopic device and a connection piece 43 for the support forks, respectively.
  • a tele­scopic device makes it possible to reduce the pressure acting on the greater piston area in the first step in order to prevent the raising of a load beyond the maximum allowable.

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)
  • Forklifts And Lifting Vehicles (AREA)
EP19880115980 1987-10-01 1988-09-28 Dispositif hydraulique télescopique Expired EP0310022B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK5154/87 1987-10-01
DK515487A DK159289C (da) 1987-10-01 1987-10-01 Hydraulisk teleskopanordning

Publications (2)

Publication Number Publication Date
EP0310022A1 true EP0310022A1 (fr) 1989-04-05
EP0310022B1 EP0310022B1 (fr) 1992-04-08

Family

ID=8139930

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880115980 Expired EP0310022B1 (fr) 1987-10-01 1988-09-28 Dispositif hydraulique télescopique

Country Status (3)

Country Link
EP (1) EP0310022B1 (fr)
DE (1) DE3869893D1 (fr)
DK (1) DK159289C (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20020080300A (ko) * 2002-09-09 2002-10-23 최준호 양방향 길이조절용 가스실린더
EP2025638A1 (fr) * 2007-07-31 2009-02-18 Iotti Giovanni S.r.l. Vérin hydraulique télescopique à double effet

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR564462A (fr) * 1922-04-11 1923-12-31 Perfectionnement dans les vérins
US1812577A (en) * 1928-04-27 1931-06-30 Rogers Products Company Inc Lifting jack
FR949840A (fr) * 1947-07-18 1949-09-09 Dispositif limiteur de pression pour crics, vérins, pompes et autres
DE1282268B (de) * 1966-10-18 1968-11-07 Demag Baggerfabrik G M B H Teleskopausleger mit mehreren ineinander bewegbaren Auslegerteilen
DE2657831A1 (de) * 1976-12-21 1978-06-22 Giehl Algi Kg Masch Hydraulischer teleskopkolbenantrieb fuer hubvorrichtungen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR564462A (fr) * 1922-04-11 1923-12-31 Perfectionnement dans les vérins
US1812577A (en) * 1928-04-27 1931-06-30 Rogers Products Company Inc Lifting jack
FR949840A (fr) * 1947-07-18 1949-09-09 Dispositif limiteur de pression pour crics, vérins, pompes et autres
DE1282268B (de) * 1966-10-18 1968-11-07 Demag Baggerfabrik G M B H Teleskopausleger mit mehreren ineinander bewegbaren Auslegerteilen
DE2657831A1 (de) * 1976-12-21 1978-06-22 Giehl Algi Kg Masch Hydraulischer teleskopkolbenantrieb fuer hubvorrichtungen

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, vol. 7, no. 110 (M-214)[1255], 13th May 1983; & JP-A-58 030 505 (NIHON KIKI KOGYO K.K.) 23-02-1983 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20020080300A (ko) * 2002-09-09 2002-10-23 최준호 양방향 길이조절용 가스실린더
EP2025638A1 (fr) * 2007-07-31 2009-02-18 Iotti Giovanni S.r.l. Vérin hydraulique télescopique à double effet

Also Published As

Publication number Publication date
DK159289B (da) 1990-09-24
EP0310022B1 (fr) 1992-04-08
DK159289C (da) 1991-02-25
DE3869893D1 (de) 1992-05-14
DK515487A (da) 1989-04-02
DK515487D0 (da) 1987-10-01

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