EP 0063025 A1 19821020 - Hydraulic control circuit for an hydraulic ram.
Title (en)
Hydraulic control circuit for an hydraulic ram.
Title (de)
Hydraulischer Steuerkreis für einen Hydraulikzylinder.
Title (fr)
Circuit de commande hydraulique pour un vérin hydraulique.
Publication
Application
Priority
GB 8110699 A 19810406
Abstract (en)
An hydraulic control circuit for the hydraulic rams (1) of the boom of an excavator includes a servo-controlled hydraulic selector valve (14) for selectively connecting a source of hydraulic pressure (12, 13) to the rams for raising or lowering the boom. Load control valves (4) connected to the raising sides of the rams include pilot-operated relief valves (7) for controlling the outlet of hydraulic fluid from the rams during lowering of the boom. In order to provide for a fast rate of descent of the boom, when required, the relief valves (7) are controlled by an hydraulic intensifier (11a) which is responsive to operation of the servo hand controller (16) upon lowering of the boom. The hydraulic pressure signal from the appropriate line (15) connecting the servo controller to the selector valve (14) is applied to the input (24) of the hydraulic intensifier, upon selection of the lowering mode, and its output signal is fed to the pilot lines (10) of the relief valves (7).
IPC 1-7
IPC 8 full level
F15B 11/08 (2006.01); F15B 13/01 (2006.01)
CPC (source: EP)
F15B 11/08 (2013.01); F15B 13/015 (2013.01); F15B 2211/30515 (2013.01); F15B 2211/40584 (2013.01); F15B 2211/41527 (2013.01); F15B 2211/50518 (2013.01); F15B 2211/5153 (2013.01); F15B 2211/528 (2013.01); F15B 2211/56 (2013.01); F15B 2211/575 (2013.01); F15B 2211/6355 (2013.01); F15B 2211/75 (2013.01); F15B 2211/8636 (2013.01); F15B 2211/8752 (2013.01)
Citation (search report)
- [A] DE 1550452 A1 19690821 - PRESCH MARTIN
- [A] DE 2424973 A1 19751204 - MONTAN HYDRAULIK GMBH & CO KG
- [A] DE 1600970 A1 19700618 - BERLIN SPEZIALFAHRZEUGWERK
- [A] US 3943825 A 19760316 - BIANCHETTA DONALD L, et al
- [A] GB 929481 A 19630626 - NEW YORK AIR BRAKE CO
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
DOCDB simple family (application)
EP 82301825 A 19820406