EP0439436A2 - Geschwindigkeitssteuervorrichtung für Gabelstaplerausrüstung - Google Patents
Geschwindigkeitssteuervorrichtung für Gabelstaplerausrüstung Download PDFInfo
- 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- Withdrawn
Links
Images
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.
Landscapes
- 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)
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 (de) | 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 (de) |
IT (1) | IT1239092B (de) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006034375A2 (en) * | 2004-09-23 | 2006-03-30 | Crown Equipment Corporation | Materials handling vehicle comprising an electronically controlled valve |
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)
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 (en) * | 1987-02-25 | 1988-09-07 | Caterpillar Industrial Inc. | Load lifting device load sensing |
-
1990
- 1990-01-24 IT IT40012A patent/IT1239092B/it active IP Right Grant
-
1991
- 1991-01-18 EP EP19910830009 patent/EP0439436A3/en not_active Withdrawn
Patent Citations (6)
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 (en) * | 1987-02-25 | 1988-09-07 | Caterpillar Industrial Inc. | Load lifting device load sensing |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006034375A2 (en) * | 2004-09-23 | 2006-03-30 | Crown Equipment Corporation | Materials handling vehicle comprising an electronically controlled valve |
WO2006034375A3 (en) * | 2004-09-23 | 2006-05-11 | Crown Equip Corp | Materials handling vehicle comprising an electronically controlled valve |
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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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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AK | Designated contracting states |
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PUAL | Search report despatched |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 19930429 |