EP0439436A2 - Dispositif de commande de vitesse variable pour À©quipement de chariot-élévateur - Google Patents

Dispositif de commande de vitesse variable pour À©quipement de chariot-élévateur Download PDF

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Publication number
EP0439436A2
EP0439436A2 EP91830009A EP91830009A EP0439436A2 EP 0439436 A2 EP0439436 A2 EP 0439436A2 EP 91830009 A EP91830009 A EP 91830009A EP 91830009 A EP91830009 A EP 91830009A EP 0439436 A2 EP0439436 A2 EP 0439436A2
Authority
EP
European Patent Office
Prior art keywords
fork lift
motor
descent
lift
proportional valve
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.)
Withdrawn
Application number
EP91830009A
Other languages
German (de)
English (en)
Other versions
EP0439436A3 (en
Inventor
Pierino Polonelli
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.)
Zapi SpA
Original Assignee
Zapi SpA
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 Zapi SpA filed Critical Zapi SpA
Publication of EP0439436A2 publication Critical patent/EP0439436A2/fr
Publication of EP0439436A3 publication Critical patent/EP0439436A3/en
Withdrawn legal-status Critical Current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
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/24—Electrical devices or systems

Definitions

  • the present invention relates to a variable speed control device for fork lift trucks.
  • the prior art embraces fork lift trucks in which the operator seat is elevated and lowered together with the lifting gear of the truck, in such a way that the operator retains direct visual control when placing or picking up objects, typically in warehouse duties.
  • the elevating and lowering movements in question need to be as linear and continuous as possible, free of sudden variations in speed. This is a requirement likewise in the case of fork lift trucks used for handling particularly delicate objects or equipment.
  • conventional fork lift trucks used in warehouse duties operate off a direct current power supply, and are equipped with a d.c. motor driving a hydraulic pump by which a hydraulic cylinder is extended upward to elevate the fork lift.
  • the motor is piloted at variable speed by a control circuit commonly known as a 'chopper', powered by the truck battery and operated manually by way of a knob.
  • the lift system also comprises a proportional valve serving to control the descent movement, which is interlocked to an electronic circuit board and operated by a further knob.
  • the object of the present invention is to overcome the drawbacks mentioned above, and in particular to afford control over the elevation and descent of a fork lift using a single electronic speed control circuit, thereby obtaining reduced cost, simplified construction and increased dependability.
  • a further object consists in making certain that elevation and descent movements are rendered free from sudden variations in speed, and providing a single manual control to operate both of the two functions, in such a way as to reduce costs and rationalize construction further still, increase long term reliability and ensure better handling and safety.
  • variable speed control device intended for use in a fork lift truck comprising a hydraulic lift system, and a d.c. motor by which the pump of the lift system is driven, and characterized in that it comprises a single electronic circuit designed to pilot the operation both of the d.c. motor, in driving the hydraulic pump to elevate the fork lift, and of a proportional valve by which the descent of the fork lift is controlled.
  • 1 denotes an electronic speed control circuit supplied with power from a battery 2, which is designed to pilot the operation of a d.c. motor 3 and a proportional valve 4.
  • the motor 3 drives a pump 5 by which fluid (oil) is drawn from a tank 6 and directed under pressure into a lift cylinder 7 so as to elevate a fork mechanism of conventional embodiment (not shown).
  • the proportional valve 4 serves to return oil from the cylinder 7 to the tank 6 with the lift descending.
  • the electronic circuit 1 comprises a microprocessor denoted 9 to which a plurality of inputs 10, ported externally of the enclosure housing the circuit, are connected by way of a relative interface 11. Similarly, a plurality of externally ported outputs 12 are connected by way of a further interface 13.
  • An 8-bit data transmission bus connects the micro processor 9 to an EPROM type memory 14 in which the reference software is stored, and in particular the operating curves of the proportional valve and the motor.
  • 15 denotes an analog/digital converter 15 by which signals from the motor, proportional valve and potentiometer are rendered intelligible for control purposes.

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Structural Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Civil Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Forklifts And Lifting Vehicles (AREA)
EP19910830009 1990-01-24 1991-01-18 A variable speed control device for fork lift equipment Withdrawn EP0439436A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT400120 1990-01-24
IT40012A IT1239092B (it) 1990-01-24 1990-01-24 Dispositivo variatore di velocita'in carrello elevatore.

Publications (2)

Publication Number Publication Date
EP0439436A2 true EP0439436A2 (fr) 1991-07-31
EP0439436A3 EP0439436A3 (en) 1992-10-28

Family

ID=11246512

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910830009 Withdrawn EP0439436A3 (en) 1990-01-24 1991-01-18 A variable speed control device for fork lift equipment

Country Status (2)

Country Link
EP (1) EP0439436A3 (fr)
IT (1) IT1239092B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006034375A2 (fr) * 2004-09-23 2006-03-30 Crown Equipment Corporation Vanne commandee electroniquement pour vehicule de manipulation de materiaux
US8924103B2 (en) 2011-02-16 2014-12-30 Crown Equipment Corporation Materials handling vehicle estimating a speed of a movable assembly from a lift motor speed

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4097791A (en) * 1975-12-01 1978-06-27 Towmotor Corporation Delayed turn-on and turn-off control circuit
FR2499961A1 (fr) * 1981-02-19 1982-08-20 Komatsu Forklift Chariot elevateur et dispositif de commande electronique de ce chariot
GB2095861A (en) * 1981-03-31 1982-10-06 Toyoda Automatic Loom Works Fork lift control system
US4586331A (en) * 1983-05-26 1986-05-06 Caterpillar Industrial Inc. Automatic hydraulic speed control
FR2603271A1 (fr) * 1986-08-27 1988-03-04 Jungheinrich Kg Chariot elevateur, en particulier chariot elevateur industriel, a mat de levage
WO1988006566A1 (fr) * 1987-02-25 1988-09-07 Caterpillar Industrial Inc. Dispositif de levage de charge detectant la charge

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4097791A (en) * 1975-12-01 1978-06-27 Towmotor Corporation Delayed turn-on and turn-off control circuit
FR2499961A1 (fr) * 1981-02-19 1982-08-20 Komatsu Forklift Chariot elevateur et dispositif de commande electronique de ce chariot
GB2095861A (en) * 1981-03-31 1982-10-06 Toyoda Automatic Loom Works Fork lift control system
US4586331A (en) * 1983-05-26 1986-05-06 Caterpillar Industrial Inc. Automatic hydraulic speed control
FR2603271A1 (fr) * 1986-08-27 1988-03-04 Jungheinrich Kg Chariot elevateur, en particulier chariot elevateur industriel, a mat de levage
WO1988006566A1 (fr) * 1987-02-25 1988-09-07 Caterpillar Industrial Inc. Dispositif de levage de charge detectant la charge

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006034375A2 (fr) * 2004-09-23 2006-03-30 Crown Equipment Corporation Vanne commandee electroniquement pour vehicule de manipulation de materiaux
WO2006034375A3 (fr) * 2004-09-23 2006-05-11 Crown Equip Corp Vanne commandee electroniquement pour vehicule de manipulation de materiaux
US7344000B2 (en) 2004-09-23 2008-03-18 Crown Equipment Corporation Electronically controlled valve for a materials handling vehicle
AU2005286765B2 (en) * 2004-09-23 2010-11-18 Crown Equipment Corporation Materials handling vehicle comprising an electronically controlled valve
CN101027244B (zh) * 2004-09-23 2011-06-15 克朗设备公司 包括电控阀的材料装卸车辆
US8924103B2 (en) 2011-02-16 2014-12-30 Crown Equipment Corporation Materials handling vehicle estimating a speed of a movable assembly from a lift motor speed
US8935058B2 (en) 2011-02-16 2015-01-13 Crown Equipment Corporation Materials handling vehicle estimating a speed of a movable assembly from a lift motor speed
US9296598B2 (en) 2011-02-16 2016-03-29 Crown Equipment Corporation Materials handling vehicle measuring electric current flow into/out of a hydraulic system motor
US9394151B2 (en) 2011-02-16 2016-07-19 Crown Equipment Corporation Materials handling vehicle monitoring a pressure of hydraulic fluid within a hydraulic structure
US9751740B2 (en) 2011-02-16 2017-09-05 Crown Equipment Corporation Materials handling vehicle estimating a speed of a movable assembly from a lift motor speed

Also Published As

Publication number Publication date
IT9040012A0 (it) 1990-01-24
IT1239092B (it) 1993-09-21
EP0439436A3 (en) 1992-10-28
IT9040012A1 (it) 1991-07-24

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