WO1982002024A1 - An electronic weighing device for pallet-lifting apparatuss - Google Patents

An electronic weighing device for pallet-lifting apparatuss Download PDF

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Publication number
WO1982002024A1
WO1982002024A1 PCT/SE1981/000363 SE8100363W WO8202024A1 WO 1982002024 A1 WO1982002024 A1 WO 1982002024A1 SE 8100363 W SE8100363 W SE 8100363W WO 8202024 A1 WO8202024 A1 WO 8202024A1
Authority
WO
WIPO (PCT)
Prior art keywords
lifting
pallet
force
weighing device
sensing means
Prior art date
Application number
PCT/SE1981/000363
Other languages
French (fr)
Inventor
Ab Ergotest
Original Assignee
Persson Lars E
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 Persson Lars E filed Critical Persson Lars E
Publication of WO1982002024A1 publication Critical patent/WO1982002024A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
    • G01G19/08—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for incorporation in vehicles
    • G01G19/083—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for incorporation in vehicles lift truck scale
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62B—HAND-PROPELLED VEHICLES, e.g. HAND CARTS OR PERAMBULATORS; SLEDGES
    • B62B2203/00—Grasping, holding, supporting the objects
    • B62B2203/50—Grasping, holding, supporting the objects comprising weighing means

Definitions

  • An electronic weighing device for pallet-lifting apparatus An electronic weighing device for pallet-lifting apparatus
  • the present invention relates to an electronic weighing device for pallet-lifting apparatus having a substantially vertically arranged lifting cylinder, said weighing device comprising a load-sensing means including a load- transducer arranged to absorb the forces obtained when the lifting apparatus is loaded; an electronic weight indicator coupled to the load transducer; and a limit switch arranged to close the current circuit to the weight indicator when the forks of the pallet-lifting apparatus reach a given level.
  • An object of the present invention is to provide an electronic weighing device which can readily be fitted to existing pallet-lifting apparatuses, thereby to eliminate the aforementioned problem.
  • the weighing device is characterized in that the load-sensing means and the load transducer are mounted on the lifting cylinder of the pallet-lifting apparatus.
  • the limit switch is arranged to close the supply of current to the weight indicator only when the lifting forks move upwardly.
  • the load transducer of the load-sensing means may comprise a wire strain gauge or an hydraulic transducer.
  • the load-sensing means may be mounted at the top of the lifting cylinder or at the bottom thereof.
  • Figure 1A is a perspective view of a pallet-lifting apparatus provided with a load-sensing means according to the invention
  • Figure 1B is a side view of a lifting cylinder having a load-sensing means according to the invention mounted thereon, said view being in larger scale than the scale of Figure 1A;
  • Figure 2 is a diagrammatic view of the current-supply circuit of the weight indicator, said circuit including a current source, a switch and a weight-sensing means;
  • Figure 3 is a diagrammatic side view of the pallet-lifting apparatus according to Figure 1;
  • Figure 4 illustrates diagrammatically the forces and moments acting on the lifting apparatus.
  • the pallet-lifting apparatus illustrated in Figure IB is a conventional lifting apparatus intended to move pallets, and then lifting them some centimeters by means of two lifting forks 1, 2 each of which is supported at one end on a respective pair of wheels 3 and 4.
  • the forks are carried at the other end thereof by a pair of wheels 5, together with the remaining components of the lifting apparatus.
  • the height of the forks 1 , 2 above the ground is regulated hydraulically by means of operating means (not shown) arranged at the top of an operating bar 6.
  • the height of the forks is controlled hydraulically by means of a substantially vertically arranged hydraulic piston-cylinder device 7.
  • a load-sensing means 8 incorporating a load transducer according to the invention is mounted on the upper end of the piston rod 9 of the piston-cylinder device 7.
  • the load or weight sensing device can also be placed beneath the hydraulic lifting cylinder 7. In both cases, the sensing means absorbs the force created when the lifting apparatus is loaded.
  • the weighing operation effected with the aid of this load, is, however, dependent on the level of the piston in the cylinder and must therefore always be carried out at a given level of the piston of the piston-cylinder device. This level is determined by means of a limit switch.
  • Figure 1B illustrates in detail the construction of the piston-cylinder device 7 .
  • Piston rod 9 is provided at its upper end with a hardened plane washer 16 on which rests a ball 17 intended to reduce or eliminate bending in the radial direction of the rod.
  • Ball 17 carries a bolt 18 having a spherical contact surface against the ball.
  • the load-sensing means 8 is mounted on the bolt 18 and is supported by a stud 19.
  • the two pairs of wheels 3, 4 rest always on the floor, i.e. the wheels carry always the load in a pallet-lifting apparatus. Moreover, the package carried by the forks 1, 2 loads continuously the load transducer.
  • FIG. 2 illustrates schematically the current supply circuit for a weight indicator 10 having a display unit 20 which is illuminated and can be read when reaching the given level of the piston of the piston-cylinder device.
  • the transducer 11 of the weight or load sensing means is connected to the weight indicator 10 via an electric conductor 12.
  • the weight indicator 10 is supplied with current from a battery or accumulator 13, having an operating time of approximately ten hours, whereat a limit switch 15 is incorporated in the conductor 14, between the indicator 10 and the battery 13.
  • the switch 15 is arranged to close the circuit 14 at a given level of the piston of the piston-cylinder device, the display 20 of the indicator being energized so that the weight loading the forks 1, 2 can be read off.
  • the indicator 10 is calibrated to give the correct weight at the given level of the piston, since the force exerted on the lifting cylinder, and there with on the load and weight sensing means is level dependent.
  • the limit switch 15 is arranged to close the current circuit 14 only when the piston of the piston-cylinder device moves upwards. At a predetermined level the display unit 20 will then be illuminated and the weight of the package can be read off. When the forks 1, 2 are unloaded display unit 20 indicates zero at said level. A normal weighing operation lasts 10 - 15 seconds implying that the battery capacity suffices for approximately 2000 weighings. Before transporting the goods or pallets the forks 1, 2 are lowered until display unit 20 is switched off.
  • the load transducer can comprise either a wire strain gauge, so-called load cell, or a hydraulic force transducer.
  • FIG 3 is illustrated schematically the operation of the lifting apparatus linkage system 21.
  • the force in cylinder 7 is sensed by load-sensing means 8.
  • Load G on wheels 4 loads the moment arm L1.
  • the moment around the fulcrum 22 is GL 1 cos ⁇ and the force in linkage system bar 21 is then:
  • This force F st which is sensed by the load-sensing a means 8 is thus dependent on angle and thus on the height of forks 2 above the floor.

Abstract

Electronic weighing device for a pallet-lifting apparatus having a substantially vertically arranged lifting piston-cylinder device (7). The weighing device includes a force-sensing means (8) with a force transducer arranged to absorb the force created when the lifting apparatus is loaded. Coupled to the force transducer is an electronic weight indicator and a limit switch arranged to close the current circuit to the weight indicator at a given level of the lifting forks (1, 2) of the pallet-lifting apparatus. The force-sensing means (8) with force transducer is mounted on the lifting cylinder (7) of the pallet-lifting apparatus.

Description

An electronic weighing device for pallet-lifting apparatus
The present invention relates to an electronic weighing device for pallet-lifting apparatus having a substantially vertically arranged lifting cylinder, said weighing device comprising a load-sensing means including a load- transducer arranged to absorb the forces obtained when the lifting apparatus is loaded; an electronic weight indicator coupled to the load transducer; and a limit switch arranged to close the current circuit to the weight indicator when the forks of the pallet-lifting apparatus reach a given level.
Known pallet-lifting apparatuses lack any form of weighing device which renders impossible the weight of individual packages to be checked when loaded onto a vehicle. Consequently, it is necessary to accept that the given weight of the package is correct. Unfortunately, this offen means that the weight of the package is greater than the given weight, which means that the load carried by the vehicle is in excess of the lawful load.
An object of the present invention is to provide an electronic weighing device which can readily be fitted to existing pallet-lifting apparatuses, thereby to eliminate the aforementioned problem.
The weighing device according to the invention is characterized in that the load-sensing means and the load transducer are mounted on the lifting cylinder of the pallet-lifting apparatus. In accordance with a particularly preferred embodiment of the invention, the limit switch is arranged to close the supply of current to the weight indicator only when the lifting forks move upwardly. The load transducer of the load-sensing means may comprise a wire strain gauge or an hydraulic transducer. The load-sensing means may be mounted at the top of the lifting cylinder or at the bottom thereof.
So that the invention will be more readily understood and further features thereof made apparent, an exemplary embodiment of the invention will now be described with reference to the accompanying drawings, in which Figure 1A is a perspective view of a pallet-lifting apparatus provided with a load-sensing means according to the invention;
Figure 1B is a side view of a lifting cylinder having a load-sensing means according to the invention mounted thereon, said view being in larger scale than the scale of Figure 1A;
Figure 2 is a diagrammatic view of the current-supply circuit of the weight indicator, said circuit including a current source, a switch and a weight-sensing means; Figure 3 is a diagrammatic side view of the pallet-lifting apparatus according to Figure 1; and
Figure 4 illustrates diagrammatically the forces and moments acting on the lifting apparatus.
The pallet-lifting apparatus illustrated in Figure IB is a conventional lifting apparatus intended to move pallets, and then lifting them some centimeters by means of two lifting forks 1, 2 each of which is supported at one end on a respective pair of wheels 3 and 4. The forks are carried at the other end thereof by a pair of wheels 5, together with the remaining components of the lifting apparatus. The height of the forks 1 , 2 above the ground is regulated hydraulically by means of operating means (not shown) arranged at the top of an operating bar 6. The height of the forks is controlled hydraulically by means of a substantially vertically arranged hydraulic piston-cylinder device 7. A load-sensing means 8 incorporating a load transducer according to the invention is mounted on the upper end of the piston rod 9 of the piston-cylinder device 7. The load or weight sensing device can also be placed beneath the hydraulic lifting cylinder 7. In both cases, the sensing means absorbs the force created when the lifting apparatus is loaded. The weighing operation, effected with the aid of this load, is, however, dependent on the level of the piston in the cylinder and must therefore always be carried out at a given level of the piston of the piston-cylinder device. This level is determined by means of a limit switch. Figure 1B illustrates in detail the construction of the piston-cylinder device 7 . Piston rod 9 is provided at its upper end with a hardened plane washer 16 on which rests a ball 17 intended to reduce or eliminate bending in the radial direction of the rod. Ball 17 carries a bolt 18 having a spherical contact surface against the ball. The load-sensing means 8 is mounted on the bolt 18 and is supported by a stud 19.
The two pairs of wheels 3, 4 rest always on the floor, i.e. the wheels carry always the load in a pallet-lifting apparatus. Moreover, the package carried by the forks 1, 2 loads continuously the load transducer.
Figure 2 illustrates schematically the current supply circuit for a weight indicator 10 having a display unit 20 which is illuminated and can be read when reaching the given level of the piston of the piston-cylinder device. The transducer 11 of the weight or load sensing means is connected to the weight indicator 10 via an electric conductor 12. The weight indicator 10 is supplied with current from a battery or accumulator 13, having an operating time of approximately ten hours, whereat a limit switch 15 is incorporated in the conductor 14, between the indicator 10 and the battery 13. The switch 15 is arranged to close the circuit 14 at a given level of the piston of the piston-cylinder device, the display 20 of the indicator being energized so that the weight loading the forks 1, 2 can be read off. Thus, the indicator 10 is calibrated to give the correct weight at the given level of the piston, since the force exerted on the lifting cylinder, and there with on the load and weight sensing means is level dependent. The limit switch 15 is arranged to close the current circuit 14 only when the piston of the piston-cylinder device moves upwards. At a predetermined level the display unit 20 will then be illuminated and the weight of the package can be read off. When the forks 1, 2 are unloaded display unit 20 indicates zero at said level. A normal weighing operation lasts 10 - 15 seconds implying that the battery capacity suffices for approximately 2000 weighings. Before transporting the goods or pallets the forks 1, 2 are lowered until display unit 20 is switched off.
The load transducer can comprise either a wire strain gauge, so-called load cell, or a hydraulic force transducer. In Figure 3 is illustrated schematically the operation of the lifting apparatus linkage system 21. By pumping out the piston in lifting cylinder 7 the lifting apparatus frame with forks 2 is raised from the floor. The force in cylinder 7 is sensed by load-sensing means 8. In order to attain a correct weight indication of the load on" forks 2 the indication of the load figure must always occur at the same height from the floor. This will be explained with reference to Figure 4. Load G on wheels 4 loads the moment arm L1. The moment around the fulcrum 22 is GL1 cosα and the force in linkage system bar 21 is then:
Figure imgf000006_0001
This force Fst which is sensed by the load-sensing a means 8 is thus dependent on angle and thus on the height of forks 2 above the floor.

Claims

1. An electronic weighing device for pallet-lifting apparatus having a substantially vertically arranged lifting piston-cylinder device (7) including a load-sensing means (8) with a force transducer (11) arranged to absorb the force generated when the lifting apparatus is loaded; an electronic weight indicator (10) connected to the force transducer (11); and a limit switch (15) arranged to close the current circuit (14) to the weight indicator (10) at a given level of the lifting forks (1, 2) of the pallet-lifting apparatus, characterized in that the force-sensing means (8) with force transducer (11) is mounted on the lifting cylinder (7) of the pallet-lifting apparatus. 2. An electronic weighing device according to claim 1, characterized in that the limit switch (15) is arranged to close the current circuit (14) to the weight indicator
(10) only during upward movement of the lifting forks (1,
2).
3. Ah electronic weighing device according to claim 1 or claim 2, characterized in that the force transducer
(11) is a strain gauge.
4. An electronic weighing device according to claim 1 or claim 2, characterized in that the force transducer (11), is a hydraulic transducer.
5. An electronic weighing device according to any one of claims 1 - 4, characterized in that the force-sensing means (8) is mounted on the top of the lifting cylinder.
6. An electronic weighing device according to any one of claims 1 - 4, characterized in that the force-sensing means is mounted beneath the lifting cylinder.
PCT/SE1981/000363 1980-12-16 1981-12-08 An electronic weighing device for pallet-lifting apparatuss WO1982002024A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8008841801216 1980-12-16
SE8008841 1980-12-16

Publications (1)

Publication Number Publication Date
WO1982002024A1 true WO1982002024A1 (en) 1982-06-24

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Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (3)

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EP (1) EP0066578A1 (en)
JP (1) JPS57502136A (en)
WO (1) WO1982002024A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0177891A2 (en) * 1984-10-05 1986-04-16 Franz Balduin Weighing device
DE3436552A1 (en) * 1984-10-05 1986-04-17 Balduin, Franz, 5100 Aachen Low-lift platform truck for transporting pallets
US4824315A (en) * 1986-07-21 1989-04-25 Zoller-Kipper Gmbh Equipment for emptying containers statement as to rights to inventions made under federally-sponsored research and development
WO1991008977A1 (en) * 1989-12-18 1991-06-27 Jensen Bjoern Holger A lifting device such as a lifting cart with means for measuring the weight of the lifted load
NL1012571C2 (en) * 1999-07-12 2001-01-15 Ravas Europ B V Pallet truck.
NL2004570C2 (en) * 2010-04-16 2011-10-18 Ravas Europ B V HANDLIFT.
WO2018088895A1 (en) * 2016-11-14 2018-05-17 Ravas Europe B.V. Pallet truck

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2850181A (en) * 1953-11-27 1958-09-02 Union Metal Mfg Co Scale for lift truck or the like
US3066807A (en) * 1961-04-19 1962-12-04 Elwell Parker Electric Co Industrial truck
US3431992A (en) * 1966-12-16 1969-03-11 Smithkline Corp Lift truck scale
US3587760A (en) * 1968-04-17 1971-06-28 Voest Ag Vehicle for transporting and weighing metallurgical vessels
US3589459A (en) * 1968-05-20 1971-06-29 Lansing Bagwall Ltd Industrial pallet truck with hydraulic weighing means
DE2164945B2 (en) * 1971-12-28 1974-10-10 Hans H. Meyer Kg Maschinenbau, 3320 Salzgitter
US3910363A (en) * 1974-12-27 1975-10-07 Allegany Technology Inc Weighing device for fork lift truck

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2850181A (en) * 1953-11-27 1958-09-02 Union Metal Mfg Co Scale for lift truck or the like
US3066807A (en) * 1961-04-19 1962-12-04 Elwell Parker Electric Co Industrial truck
US3431992A (en) * 1966-12-16 1969-03-11 Smithkline Corp Lift truck scale
US3587760A (en) * 1968-04-17 1971-06-28 Voest Ag Vehicle for transporting and weighing metallurgical vessels
US3589459A (en) * 1968-05-20 1971-06-29 Lansing Bagwall Ltd Industrial pallet truck with hydraulic weighing means
DE2164945B2 (en) * 1971-12-28 1974-10-10 Hans H. Meyer Kg Maschinenbau, 3320 Salzgitter
US3910363A (en) * 1974-12-27 1975-10-07 Allegany Technology Inc Weighing device for fork lift truck

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0177891A2 (en) * 1984-10-05 1986-04-16 Franz Balduin Weighing device
DE3436552A1 (en) * 1984-10-05 1986-04-17 Balduin, Franz, 5100 Aachen Low-lift platform truck for transporting pallets
EP0177891A3 (en) * 1984-10-05 1987-04-15 Franz Balduin Weighing device
US4824315A (en) * 1986-07-21 1989-04-25 Zoller-Kipper Gmbh Equipment for emptying containers statement as to rights to inventions made under federally-sponsored research and development
WO1991008977A1 (en) * 1989-12-18 1991-06-27 Jensen Bjoern Holger A lifting device such as a lifting cart with means for measuring the weight of the lifted load
NL1012571C2 (en) * 1999-07-12 2001-01-15 Ravas Europ B V Pallet truck.
WO2001003990A1 (en) 1999-07-12 2001-01-18 Ravas Europe B.V. Mobile lifting device and weighing device therefor
US6855894B1 (en) 1999-07-12 2005-02-15 Ravas Europe B.V. Mobile lifting device and weighing device therefor
NL2004570C2 (en) * 2010-04-16 2011-10-18 Ravas Europ B V HANDLIFT.
WO2011129692A1 (en) * 2010-04-16 2011-10-20 Ravas Europe B.V. Hand lift truck
CN103038121A (en) * 2010-04-16 2013-04-10 拉瓦斯欧洲有限责任公司 Hand lift truck
WO2018088895A1 (en) * 2016-11-14 2018-05-17 Ravas Europe B.V. Pallet truck
CN109937168A (en) * 2016-11-14 2019-06-25 拉瓦斯欧洲有限公司 Pallet Truck
US10899375B2 (en) 2016-11-14 2021-01-26 Ravas Europe B. V. Pallet truck
CN109937168B (en) * 2016-11-14 2022-03-25 拉瓦斯欧洲有限公司 Trailer

Also Published As

Publication number Publication date
EP0066578A1 (en) 1982-12-15
JPS57502136A (en) 1982-12-02

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