EP 0010699 A1 19800514 - Fluid motor control circuit with fast-acting quick-drop valve.
Title (en)
Fluid motor control circuit with fast-acting quick-drop valve.
Title (de)
Steuerung für Hydraulikmotoren mit schnell ansprechendem Eilgangventil.
Title (fr)
Circuit de commande pour moteurs hydrauliques avec soupape de descente rapide à action rapide.
Publication
Application
Priority
US 95677578 A 19781101
Abstract (en)
A control circuit (11, 11b) for a fluid pressure-operated cylinder (13, 13b) or the like has a quick-drop valve (12, 12b) which enables faster gravity-assisted lowering of a load (16, 16b) and which quickly shifts to a power-down mode of operation whon dropping of the load by gravity ceases. Means (47, 47b, 54, 54b, 56, 56b) sensing flow rate to the head end of the cylinder and sensing cavitation in the head end initiate the quick-drop operation at which the discharge path from the cylinder back to tank is totally blocked and all discharge from the rod end is recirculated to the head end. When resistance to further lowering of the load occurs, the quick-drop valve responds by shifting to block communication betwesn ends of the cylinder while establishing a rod end discharge path to tank to initiate a power-down mode of operation quickly and without lag or bounce.
IPC 1-7
IPC 8 full level
E02F 3/85 (2006.01); E02F 3/84 (2006.01); F15B 11/024 (2006.01); F15B 13/02 (2006.01)
CPC (source: EP)
E02F 3/844 (2013.01); F15B 11/024 (2013.01); F15B 13/021 (2013.01); F15B 2011/0243 (2013.01); F15B 2011/0246 (2013.01); F15B 2211/30525 (2013.01); F15B 2211/3058 (2013.01); F15B 2211/3116 (2013.01); F15B 2211/3127 (2013.01); F15B 2211/3144 (2013.01); F15B 2211/31576 (2013.01); F15B 2211/324 (2013.01); F15B 2211/40507 (2013.01); F15B 2211/41527 (2013.01); F15B 2211/575 (2013.01); F15B 2211/75 (2013.01); F15B 2211/8609 (2013.01)
Citation (search report)
- FR 1576772 A 19690801
- US 3568707 A 19710309 - SHORE DANIEL B
- US 3474708 A 19691028 - SCHMIEL HERBERT H
- US 3654835 A 19720411 - SIEVENPIPER DONALD A
- US 3795177 A 19740305 - CRYDER J, et al
Designated contracting state (EPC)
BE DE GB
DOCDB simple family (publication)
EP 0010699 A1 19800514; EP 0010699 B1 19840418; CA 1141266 A 19830215; DE 2966924 D1 19840524; JP S5563003 A 19800512
DOCDB simple family (application)
EP 79104041 A 19791019; CA 338957 A 19791101; DE 2966924 T 19791019; JP 13304879 A 19791017