EP0126634A1 - Assemblage de mât télescopique - Google Patents

Assemblage de mât télescopique Download PDF

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Publication number
EP0126634A1
EP0126634A1 EP84303378A EP84303378A EP0126634A1 EP 0126634 A1 EP0126634 A1 EP 0126634A1 EP 84303378 A EP84303378 A EP 84303378A EP 84303378 A EP84303378 A EP 84303378A EP 0126634 A1 EP0126634 A1 EP 0126634A1
Authority
EP
European Patent Office
Prior art keywords
section
movable section
movable
fixed
carriage
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
EP84303378A
Other languages
German (de)
English (en)
Other versions
EP0126634B1 (fr
Inventor
Walter George Wardle
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.)
Boss Group Ltd
Original Assignee
Lancer Boss Ltd
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 Lancer Boss Ltd filed Critical Lancer Boss Ltd
Priority to AT84303378T priority Critical patent/ATE23513T1/de
Publication of EP0126634A1 publication Critical patent/EP0126634A1/fr
Application granted granted Critical
Publication of EP0126634B1 publication Critical patent/EP0126634B1/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
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/08—Masts; Guides; Chains

Definitions

  • This invention relates to lift trucks and more particularly to mast assemblies for lift trucks of the kind having a telescopic mast assembly which is operable to move a lifting carriage, usually provided with forks, from a lowered position at ground level to a raised position at the top of the extended mast assembly.
  • the mast assembly in three sections, comprising a fixed section secured to the chassis, and two telescopic sections movably mounted with respect to the fixed section.
  • These movable sections comprise a first movable section on which the lifting carriage is slidably mounted, and a second movable section on which the first section is slidably mounted and which is itself slidably supported on the fixed section.
  • Means are provided for extending the movable sections and for moving the carriage along the first movable section. These usually comprise hydraulic cylinders coupled to the carriage and to one or more of the sections by chains.
  • the telescopic mast assembly and the lifting carriage are usually located forward of the driving position, and known arrangements of mast assembly frequently suffer from the disadvantage of restricting the driver's view of the load and the lifting carriage from the driving position. This problem is particularly aggravated in three-section telescopic mast assemblies, as the combined width of the sections and their operating cylinders seriously hampers the driver's view.
  • the invention provides a telescopic mast assembly which achieves much improved visibility through the mast assembly.
  • a telescopic mast assembly for a lift truck comprising a fixed mast section, and two relatively movable telescopic mast sections movably mounted with respect to the fixed section, said telescopic mast sections comprising a first movable section supporting a slidably mounted lifting carriage, and a second movable section slidably mounted with respect to the fixed section, and slidably supporting the first movable section, and means for extending the movable sections and raising the carriage up the first movable section, said means comprising first hydraulic cylinder means operating between the fixed section and the second movable section, second hydraulic cylinder means operating between the second movable section and the first movable section, and third hydraulic cylinder means operating between the first movable section and the carriage.
  • hydraulic cylinder means has a number of advantages compared with the combination of hydraulic cylinders and lifting chains. Firstly, hydraulic cylinders are more reliable and have a longer life than chains and do not require the frequent adjustment which is usually necessary with a chain system. Secondly, the use of hydraulic cylinders enables the cylinders to be located in positions which do not unduly interfere with the driver's view.
  • the mast sections each suitably comprise a pair of channel section uprights
  • the first hydraulic cylinder means which operates between the fixed mast section and the second movable section comprise a pair of matched hydraulic cylinders each of which is located behind the appropriate channel section upright.
  • the third cylinder means which operates between the first movable section and the carriage comprises a single hydraulic cylinder assembly, the piston rod of which is fixed to the first movable section and the cylinder of which is fixed to the carriage. In the lowermost position of the carriage, the piston rod is fully extended, and in order to raise the carriage, the piston rod is retracted into the cylinder.
  • the piston rod By arranging for the piston rod to be retracted in order to raise the carriage, the piston rod becomes the only element in the line of sight of the driver, and as this is substantially narrower than the cylinder a significant improvement in visibility is achieved.
  • the use of a cylinder in tension also enables the bearing spread to be reduced thus maximizing the amount of extension available from the cylinder.
  • the carriage is raised by a telescopic ram acting between the first movable section and the upper part of the carriage.
  • the central part of the mast assembly above the carriage is completely clear.
  • the second hydraulic cylinder means disposed between the second movable section and the first movable section comprises a single hydraulic cylinder which is off-set in relation to the central longitudinal axis of the assembly.
  • the restriction of visibility posed by the single hydraulic cylinder is substantially reduced.
  • the three hydraulic cylinder means are hydraulically interconnected so as to operate sequentially, the sequence comprising firstly the positioning of the carriage along the first movable section, secondly the raising of the first movable section relative to the second movable section, and thirdly the lifting of the second movable section relative to the fixed section.
  • This sequential operation of the cylinders can be achieved using a single hydraulic circuit by appropriate choice of the piston diameters.
  • the channel section upright forming the mast sections are provided with strengthening flanges, and preferably the width of these flanges is substantially reduced. This can be done without unduly impairing the strength of the uprights by utilising rolled sections rather than welded sections, which have less strength in the corners than a rolled section.
  • the channel section uprights each comprise a pair of rolled angle sections which are welded together along the margins of the longer flange to produce the required channel section.
  • FIG. 1 show a telescopic mast assembly for a fork-lift truck in which the driver position is indicated by A.
  • the mast assembly is formed from a fixed section 10 which is mounted on the chassis of the vehicle via mounting brackets 8, 9 and which comprises a pair of channel section uprights 11, 12 interconnected by side plates 6, strengthening beams 7, and a transverse beam 13.
  • the fixed section 10 may be tiltable in relation to the vehicle chassis.
  • Two telescopic sections 15, 16 are movably mounted with respect to the fixed section 10. These telescopic sections comprise a first movable section 16 formed from a pair of channel section uprights 17, 18, and a second movable section 15 formed from channel sections 20, 21.
  • the first movable section 16 is slidably mounted in the second movable section 15 by means of rollers 22 which engage inside the channel section uprights 20, 21.
  • the second movable section 15 is slidably mounted in fixed section 10 by means of rollers 25 which engage within the channel section uprights 11, 12.
  • Movably mounted in relation to the first movable section 16 is a carriage assembly 26 which carries forks 27 and which is slidable relative to the first movable section 16 by means of rollers 30 which engage within the channel section uprights 17, 18.
  • the carriage 26 is movable" up and down the first movable section 16; the first movable section 16 is movable up and down the second movable section 15; and the second movable section 15 is movable up and down the fixed section 10.
  • Relative movement of these elements is provided by three hydraulic cylinder and piston assemblies.
  • These comprise a first hydraulic piston and cylinder assembly composed of a pair of matched hydraulic cylinder and pistons 32, 33 which operate between the fixed mast section 10 and the second movable section 15.
  • Each assembly comprises a cylinder 35 which is fixed at one end to the fixed section by means of a plate 34 and a piston rod 36 which is secured to a plate 37 connected to the second movable section 15. Pressurisation of cylinder 35 causes piston rod 36 to extend out of the cylinder, taking with it the second movable section 15.
  • the cylinder assemblies 32, 33 are located immediately behind the uprights 11, 12 of the fixed mast section 10, and thus do not impair visibility through the mast assembly.
  • Relative movement between the second movable section 15 and the first movable section 16 is controlled by a single hydraulic piston and cylinder assembly 40 the lower end of which is fixed to a plate 42 which is welded onto a cross-bar 41 interconnecting the uprights 20, 21 of the second movable section.
  • the piston rod 43 is connected to plate 45 which in turn is connected to and braces the uprights 17, 18 of the first movable section 16.
  • cylinder assembly 40 is off-set from the centre line of the mast assembly, and as the driving position A is also off-set, a corresponding improvement in visibility is achieved.
  • Relative movement between the carriage 26 and the first movable section 16 is controlled by a single hydraulic cylinder assembly 50 operating in tension, and the piston rod 52 of which is secured to plate 45 by brackets 55 and the cylinder 51 of which is secured at its free end to the carriage 26 via a cross brace, trunnions 24, and carriage stiles 23.
  • the extended position of the piston rod 52 corresponds to the lowermost position of the carriage 26, and in this position only the narrow piston rod is disposed in front of the driver's view.
  • the hydraulic jacks operate sequentially so that on initial operation of the lifting circuit, the carriage 26 is moved upwardly along the first movable section from the lowemost position to the uppermost position shown in dotted lines in Fig. 1. It will be appreciated that this can be achieved without extending the height of the mast assembly.
  • cylinder assembly 40 is then operated to act between the plate 45 and cross-bar 41 to raise the first movable section along the second movable section.
  • the pair of cylinders 32, 33 then act on plates 37 to raise the second movabTe section, with the first movable section and carriage, upwardly relative to the fixed section 10 so as to bring the mast to its full height.
  • the rollers which guide the telescopic movement of the sections are substantially the same width as the channel section uprights themselves.
  • the very minimal width of the flanges forming these channel section uprights is achieved by using rolled sections which have correspondingly greater strength in their corner regions than welded sections.
  • the driver's sight-lines are shown in Fig. 2, and it will be appreciated from this drawing that the use of larger flanges on the uprights themselves would substantially interfere with the free visibility provided. It will be appreciated that the crucial element in driver visibility is the ability of the driver to see the tips of the forks during a lifting operation, and as will be seen from Fig. 2, this is adequately achieved with the mast section according to the invention.

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Structural Engineering (AREA)
  • Civil Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Axle Suspensions And Sidecars For Cycles (AREA)
EP84303378A 1983-05-18 1984-05-17 Assemblage de mât télescopique Expired EP0126634B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84303378T ATE23513T1 (de) 1983-05-18 1984-05-17 Teleskopische hubgeruestanordnung.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB838313674A GB8313674D0 (en) 1983-05-18 1983-05-18 Telescopic mast assembly
GB8313674 1983-05-18

Publications (2)

Publication Number Publication Date
EP0126634A1 true EP0126634A1 (fr) 1984-11-28
EP0126634B1 EP0126634B1 (fr) 1986-11-12

Family

ID=10542921

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84303378A Expired EP0126634B1 (fr) 1983-05-18 1984-05-17 Assemblage de mât télescopique

Country Status (4)

Country Link
EP (1) EP0126634B1 (fr)
AT (1) ATE23513T1 (fr)
DE (2) DE3461275D1 (fr)
GB (1) GB8313674D0 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1046609B1 (fr) † 1999-04-21 2004-03-10 Crown Gabelstapler GmbH Chariot élévateur à mât déplaçable

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE202005012049U1 (de) * 2005-08-01 2006-12-14 Liebherr-Werk Ehingen Gmbh Teleskopierbarer Schiebeholm

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1033795A (fr) * 1951-03-09 1953-07-15 Cie Gen De Constr De Fours Chariot élévateur de manutention
GB1186458A (en) * 1967-09-06 1970-04-02 Eaton Yale & Towne Lift Truck Mast and Ram Assembly
FR2351908A1 (fr) * 1976-05-17 1977-12-16 Audureau Sa Mat pour chariot elevateur
DE2713808A1 (de) * 1977-03-29 1978-10-05 Linde Ag Hubgeruest fuer hublader
GB2045208A (en) * 1979-04-04 1980-10-29 Clark Equipment Co Fork-lift truck
FR2453820A1 (fr) * 1979-04-09 1980-11-07 Clark Equipment Co Mat de chariot elevateur
WO1981003014A1 (fr) * 1980-04-14 1981-10-29 Towmotor Corp Ensemble de chariot et de mat de levage de charge

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1033795A (fr) * 1951-03-09 1953-07-15 Cie Gen De Constr De Fours Chariot élévateur de manutention
GB1186458A (en) * 1967-09-06 1970-04-02 Eaton Yale & Towne Lift Truck Mast and Ram Assembly
FR2351908A1 (fr) * 1976-05-17 1977-12-16 Audureau Sa Mat pour chariot elevateur
DE2713808A1 (de) * 1977-03-29 1978-10-05 Linde Ag Hubgeruest fuer hublader
GB2045208A (en) * 1979-04-04 1980-10-29 Clark Equipment Co Fork-lift truck
FR2453820A1 (fr) * 1979-04-09 1980-11-07 Clark Equipment Co Mat de chariot elevateur
WO1981003014A1 (fr) * 1980-04-14 1981-10-29 Towmotor Corp Ensemble de chariot et de mat de levage de charge

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1046609B1 (fr) † 1999-04-21 2004-03-10 Crown Gabelstapler GmbH Chariot élévateur à mât déplaçable
EP1046609B2 (fr) † 1999-04-21 2017-07-19 Crown Gabelstapler GmbH Chariot élévateur à mât déplaçable

Also Published As

Publication number Publication date
DE3461275D1 (en) 1987-01-02
DE126634T1 (de) 1985-06-20
EP0126634B1 (fr) 1986-11-12
GB8313674D0 (en) 1983-06-22
ATE23513T1 (de) 1986-11-15

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