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WO1988006567A1 - Device in a fork truck - Google Patents

Device in a fork truck Download PDF

Info

Publication number
WO1988006567A1
WO1988006567A1 PCT/SE1988/000079 SE8800079W WO8806567A1 WO 1988006567 A1 WO1988006567 A1 WO 1988006567A1 SE 8800079 W SE8800079 W SE 8800079W WO 8806567 A1 WO8806567 A1 WO 8806567A1
Authority
WO
WIPO (PCT)
Prior art keywords
lifting
operator
station
bars
arms
Prior art date
Application number
PCT/SE1988/000079
Other languages
French (fr)
Inventor
Sveneric Ottosson
Original Assignee
Semax Truck Ab
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 Semax Truck Ab filed Critical Semax Truck Ab
Publication of WO1988006567A1 publication Critical patent/WO1988006567A1/en

Links

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
    • B66F9/12—Platforms; Forks; Other load supporting or gripping members
    • B66F9/122—Platforms; Forks; Other load supporting or gripping members longitudinally movable
    • 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
    • B66F9/12—Platforms; Forks; Other load supporting or gripping members
    • B66F9/16—Platforms; Forks; Other load supporting or gripping members inclinable relative to mast

Definitions

  • the invention relates to a device in a fork truck provided with a vertical lift mast rigidly mounted to the truck.
  • a vertical two-part lift mast is arranged ahead of the operator's station of the truck.
  • the lift mast comprises as lift means a vertically moving fork arranged between and connecting the mast elements.
  • the forward visibility of the driver is limited by the mast elements.
  • the second fundamentally different type of fork trucks comprises a bar pivotally supported behind the operator's station to rotate about a horizontal axis and extending ahead of the operator's station where the fork is supported on the bar.
  • This type of fork trucks is disclosed in US 4 553 899, GB 2 144 096 and DE 2 424 682.
  • the bar is preferably elevated by means of one or more hydraulic rams.
  • the fork is arranged to be tilted either on the free end of the bar or on an extendable arm telescoped within the bar. Such an arm gives the truck a large horizontal radius of action.
  • the bar is rather long resulting in a small horizontal displacement when the bar is elevated.
  • the placing of the bar limits the visibility of the driver.
  • the truck itself also becomes much less compact than a truck according to the type initially described.
  • An object of the present invention is to provide a compact fork truck having a large radius of action, the lift mast thereof being arranged far back on the truck to provide the best placing of the gravity point and a very good visibility.
  • FIG. 1 is a schematic view of a truck with a device according to the invention
  • FIG. 2 is a side view of the device according to the invention.
  • the truck illustrated in FIG. 1 comprises an operator's station 10, a vertical lift mast 11 mounted behind the operator's station 10, and a lifting unit 12.
  • a vertical section of the lifting unit 12 is telescoped in the Lift mast 11.
  • Two lifting arms 13 form a horisontal section of the lifting unit 12.
  • the lifting arms 13 are formed as tubes having rectangular cross section.
  • Lifting bars 14 are telescoped in the lifting arms 13 to achieve an increased horizontal radius of action.
  • At the tip of the free ends of the bars 14 a lifting means 15 is provided which connects the bars.
  • the lifting means 15 comprises two L-shaped beams having a flat cross section and forming the fork of the truck. In a rest position the beams form a laying L having a short leg 19 pointing vertically upwards and a longer leg 20 projecting vertically from the truck.
  • the beams are pivotally connected to the free ends of the beams 14.
  • the lifting unit with the arms 13 is vertically displaceable in the direction of the arrow A, the bars 14 are horizontally extendable in the direction of the arrow B, and the lifting means 15 with the fork can be tilted in the direction of the arrow C.
  • the fork is tilted while maintaining the direction of the lift mast 11 .
  • the lift arm 13 illustrated in FIG. " 2 comprises an inner hydraulic cylinder 16 for horizontal extension of the bar 14 into and out of the arm 13, and a hydraulic cylinder 18 for tilting the lifting " means 15.
  • the cylinder 16 at one end thereof is pivotally supported on a horizontal shaft 22 attached to the end of the arm 13 facing the liftmast 11.
  • the cylinder 16 is pivotally supported on a horizontal shaft 23 attached to the part of the bar 14 facing the arm 13.
  • the cylinder 16 is completely protected within the arm 13.
  • the other cylinder 18 at one end thereof is pivotally supported on a horizontal shaft 24 at the free end of the bar 14 and at the other end thereof is pivotally supported on a horizontal shaft 25 on the lifting means 15.
  • the lifting means 15 is tilted around a shaft 21 attached to a tip of a downwardly extending and tapering section of the bar 14. As is apparent from FIGS. 1 and 2 the fork may be tilted also when the bar 14 is completely extended from the arm 13.
  • the gravity point of the load is also located at minimum distance ahead of the front wheel shaft providing a compact structure of the truck.
  • the bars 14 telescoped in the horizontal lifting arms 13 allow a horizontal extension of the fork with load without an undesired simultaneous vertical movement.

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)

Abstract

The invention relates to a device in a fork truck and is applicable to trucks comprising an operator's station (10), a vertical lift mast (11) rigidly mounted on the truck behind the operator's station (10), a lifting unit (12) telescoped in the lift mast (11), and two lifting arms (13) mounted vertically to the lifting unit (12) and extending horizontally to the region of the front portion of the operator's station (10) on both sides of the operator's station (10), the lifting arms (13) being shaped as tubes having an essentially rectangular cross section. The lifting arms (13) are provided with telescopically extendable bars (14) supporting in the free ends thereof a lifting means (15) which can be tilted.

Description

DEVICE IN A FORK TRUCK
The invention relates to a device in a fork truck provided with a vertical lift mast rigidly mounted to the truck.
For many years fork trucks have been used for instance in loading and unloading heavy vehicles. Two fundamentally different types of fork trucks exist.
In a first type a vertical two-part lift mast is arranged ahead of the operator's station of the truck. The lift mast comprises as lift means a vertically moving fork arranged between and connecting the mast elements. In this type the forward visibility of the driver is limited by the mast elements. When the truck is moving it is possible to tilt the lift mast, i.a. to retain the load on the fork. When the loaded fork has been elevated a considerable displacement of the gravity point takes place when the lift mast is tilted.
The second fundamentally different type of fork trucks comprises a bar pivotally supported behind the operator's station to rotate about a horizontal axis and extending ahead of the operator's station where the fork is supported on the bar. This type of fork trucks is disclosed in US 4 553 899, GB 2 144 096 and DE 2 424 682. The bar is preferably elevated by means of one or more hydraulic rams. The fork is arranged to be tilted either on the free end of the bar or on an extendable arm telescoped within the bar. Such an arm gives the truck a large horizontal radius of action. To prevent the displacement of the gravity point from becoming too large when the bar is elevated with load on the fork, the bar is rather long resulting in a small horizontal displacement when the bar is elevated. The placing of the bar limits the visibility of the driver. The truck itself also becomes much less compact than a truck according to the type initially described.
An object of the present invention is to provide a compact fork truck having a large radius of action, the lift mast thereof being arranged far back on the truck to provide the best placing of the gravity point and a very good visibility.
The above object is achieved by the invention having obtained the characteristics of claim 1. Illustrative embodiments of the invention will be described in more detail reference being made to the accompanying drawings, in which:
FIG. 1 is a schematic view of a truck with a device according to the invention, and FIG. 2 is a side view of the device according to the invention.
The truck illustrated in FIG. 1 comprises an operator's station 10, a vertical lift mast 11 mounted behind the operator's station 10, and a lifting unit 12. A vertical section of the lifting unit 12 is telescoped in the Lift mast 11. Two lifting arms 13 form a horisontal section of the lifting unit 12. The lifting arms 13 are formed as tubes having rectangular cross section. Lifting bars 14 are telescoped in the lifting arms 13 to achieve an increased horizontal radius of action. At the tip of the free ends of the bars 14 a lifting means 15 is provided which connects the bars. The lifting means 15 comprises two L-shaped beams having a flat cross section and forming the fork of the truck. In a rest position the beams form a laying L having a short leg 19 pointing vertically upwards and a longer leg 20 projecting vertically from the truck. At the free ends of the short legs 19 the beams are pivotally connected to the free ends of the beams 14. The lifting unit with the arms 13 is vertically displaceable in the direction of the arrow A, the bars 14 are horizontally extendable in the direction of the arrow B, and the lifting means 15 with the fork can be tilted in the direction of the arrow C. Thus, the fork is tilted while maintaining the direction of the lift mast 11 .
The lift arm 13 illustrated in FIG. "2 comprises an inner hydraulic cylinder 16 for horizontal extension of the bar 14 into and out of the arm 13, and a hydraulic cylinder 18 for tilting the lifting "means 15. The cylinder 16 at one end thereof is pivotally supported on a horizontal shaft 22 attached to the end of the arm 13 facing the liftmast 11. At the other end the cylinder 16 is pivotally supported on a horizontal shaft 23 attached to the part of the bar 14 facing the arm 13. The cylinder 16 is completely protected within the arm 13. The other cylinder 18 at one end thereof is pivotally supported on a horizontal shaft 24 at the free end of the bar 14 and at the other end thereof is pivotally supported on a horizontal shaft 25 on the lifting means 15. The lifting means 15 is tilted around a shaft 21 attached to a tip of a downwardly extending and tapering section of the bar 14. As is apparent from FIGS. 1 and 2 the fork may be tilted also when the bar 14 is completely extended from the arm 13.
By placing the lift mast 11 behind the operator's station 10 the driver is given full visibility. The gravity point of the load is also located at minimum distance ahead of the front wheel shaft providing a compact structure of the truck. The bars 14 telescoped in the horizontal lifting arms 13 allow a horizontal extension of the fork with load without an undesired simultaneous vertical movement.

Claims

1. Device in a fork truck, comprising an operator's station (10), a vertical lift mast (11) rigidly mounted behind the operator's station (10), a lifting unit (12) telescoped in the lift mast (11), and two lifting arms (13) mounted vertically to the lifting unit (12) and extending horizontally to the region of the front portion of the operator's station (10) on both sides of the operator's station (10), the lifting arms (13) being shaped as tubes having an essentially rectangular cross section, c h a r a c t e r i z e d by bars (14) telescoped in the lifting arms (13), the bars (14) supporting in the free ends thereof a lifting means (15) pivoted about a transverse axis.
2. Device according to claim 1, c h a r a c t e r i z e d in that the lifting bars (14) are pivotally connected to fluid pressure means (16) inside the lifting arms (13), the fluid pressure means (16) being pivotally connected to the lifting arms (13) adjacent the base of the lifting arms (13).
3. Device according to claim 1 or 2, c h a r a c t e r i z e d in that the lifting arms (13) on the inside are provided with bearing means (17) adjacent the openings to allow extension of the lifting bars (14) with low friction.
4. Device according to any of the preceeding claims, c h a r a c t e r i z e d in that the lifting bars (14) at the extendable ends thereof a're provided with fluid pressure operated tilting means (18) pivotally connected to the lifting bars (14) and the lifting means (15) for tilting the lifting means (15).
PCT/SE1988/000079 1987-02-24 1988-02-24 Device in a fork truck WO1988006567A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8700764A SE458856B (en) 1987-02-24 1987-02-24 DEVICE FORK TRUCK WITH REAR DRIVER'S LIFT MAST
SE8700764-7 1987-02-24

Publications (1)

Publication Number Publication Date
WO1988006567A1 true WO1988006567A1 (en) 1988-09-07

Family

ID=20367643

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1988/000079 WO1988006567A1 (en) 1987-02-24 1988-02-24 Device in a fork truck

Country Status (2)

Country Link
SE (1) SE458856B (en)
WO (1) WO1988006567A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5009560A (en) * 1988-12-06 1991-04-23 Yellow Freight System, Inc. Mixed freight handling system
US5067867A (en) * 1988-12-06 1991-11-26 Yellow Freight System, Inc. Conveyor for mixed freight handling system
US5088873A (en) * 1988-12-06 1992-02-18 Yellow Freight System, Inc. Manipulator mixed freight handling system
US5174708A (en) * 1988-12-06 1992-12-29 Yellow Freight System, Inc. Boom mounted multiple stage freight lift apparatus
US5176485A (en) * 1988-12-06 1993-01-05 Yellow Freight System, Inc. Freight manipulator with articulated cantilever boom
GB2271335A (en) * 1992-10-09 1994-04-13 Boss Trucks Ltd Load handling vehicles
ITBO20120638A1 (en) * 2012-11-23 2014-05-24 Bp S R L SIDE FORKLIFT TROLLEY.

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2300430A1 (en) * 1972-01-04 1973-07-12 Lancer Boss Ltd SELF-DRIVEN LIFTING VEHICLE
DE2424682A1 (en) * 1973-05-21 1974-12-12 Loed Corp LOADING VEHICLE
US3907141A (en) * 1974-08-27 1975-09-23 Allis Chalmers Operator{3 s station optionally stationary or elevated
US4553899A (en) * 1983-11-16 1985-11-19 Riccardo Magni High lift truck with telescoping boom assemblies

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2300430A1 (en) * 1972-01-04 1973-07-12 Lancer Boss Ltd SELF-DRIVEN LIFTING VEHICLE
DE2424682A1 (en) * 1973-05-21 1974-12-12 Loed Corp LOADING VEHICLE
US3907141A (en) * 1974-08-27 1975-09-23 Allis Chalmers Operator{3 s station optionally stationary or elevated
US4553899A (en) * 1983-11-16 1985-11-19 Riccardo Magni High lift truck with telescoping boom assemblies

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5009560A (en) * 1988-12-06 1991-04-23 Yellow Freight System, Inc. Mixed freight handling system
US5067867A (en) * 1988-12-06 1991-11-26 Yellow Freight System, Inc. Conveyor for mixed freight handling system
US5088873A (en) * 1988-12-06 1992-02-18 Yellow Freight System, Inc. Manipulator mixed freight handling system
US5174708A (en) * 1988-12-06 1992-12-29 Yellow Freight System, Inc. Boom mounted multiple stage freight lift apparatus
US5176485A (en) * 1988-12-06 1993-01-05 Yellow Freight System, Inc. Freight manipulator with articulated cantilever boom
GB2271335A (en) * 1992-10-09 1994-04-13 Boss Trucks Ltd Load handling vehicles
GB2271335B (en) * 1992-10-09 1996-06-26 Boss Trucks Ltd Improvements in load handling vehicles
ITBO20120638A1 (en) * 2012-11-23 2014-05-24 Bp S R L SIDE FORKLIFT TROLLEY.
WO2014080359A1 (en) * 2012-11-23 2014-05-30 Bp S.R.L. A side lift truck

Also Published As

Publication number Publication date
SE458856B (en) 1989-05-16
SE8700764D0 (en) 1987-02-24
SE8700764L (en) 1988-08-25

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