EP 0230884 A3 19900516 - HYDRAULIC LIFTING DEVICE
Title (en)
HYDRAULIC LIFTING DEVICE
Publication
Application
Priority
DE 3602510 A 19860128
Abstract (en)
[origin: US4723107A] A hydraulic lifting mechanism, particularly suitable for a battery-powered industrial truck, including a hydraulic lifting cylinder, a hydraulic unit, operating as a pump in the load lifting operational mode, and supplying the lifting cylinder with pressure medium, and operating as a motor in the load lowering operational mode during which mode it is actuated by the pressure medium exiting from the lifting cylinder, and a DC generator coupled with the hydraulic unit operating as an electromotor in the load lifting operational mode and as a generator in the load lowering operational mode. A control valve arrangement is provided at the halfway point in the pressure path between the hydraulic cylinder and the hydraulic unit, which is controlled by a lifting mechanism control. In addition, the lifting mechanism control controls a regenerative brake circuit supplied by the DC generator in the load lowering operational mode. The control valve arrangement includes a proportional valve which is opened by the lifting mechanism control in the load lowering operational mode in accordance with a ramp-like function. The regenerative brake circuit is switched on depending on the output current of the DC generator working as a generator, if the generator output current exceeds a predetermined value. Undesirable dropping of the load in the lowering operational mode is hereby prevented during transition to regenerative braking.
IPC 1-7
IPC 8 full level
B66F 9/20 (2006.01); B66F 9/22 (2006.01); F15B 21/14 (2006.01)
CPC (source: EP US)
B66F 9/20 (2013.01 - EP US); F15B 21/14 (2013.01 - EP US)
Citation (search report)
- [A] DE 3018156 A1 19810903 - OIL DRIVE KOGYO LTD [JP]
- [A] DE 2724383 A1 19781130 - JUNGHEINRICH KG
- [A] US 3947744 A 19760330 - GRACE MICHAEL H, et al
- [AD] DE 2014605 A1 19710304 - ASEA AB
Designated contracting state (EPC)
AT BE DE FR GB IT NL SE
DOCDB simple family (publication)
US 4723107 A 19880202; AT E94149 T1 19930915; DE 3602510 A1 19870730; DE 3602510 C2 19890302; DE 3787292 D1 19931014; EP 0230884 A2 19870805; EP 0230884 A3 19900516; EP 0230884 B1 19930908
DOCDB simple family (application)
US 286687 A 19870113; AT 87100211 T 19870109; DE 3602510 A 19860128; DE 3787292 T 19870109; EP 87100211 A 19870109