EP 0339247 B1 19930811 - HYDRAULIC STEERING DEVICE FOR THE DRIVE CONTROL OF A DOUBLE-ACTING HYDRAULIC CYLINDER
Title (en)
HYDRAULIC STEERING DEVICE FOR THE DRIVE CONTROL OF A DOUBLE-ACTING HYDRAULIC CYLINDER
Publication
Application
Priority
DE 3814580 A 19880429
Abstract (en)
[origin: EP0339247A1] In a hydraulic control device for the drive control of a double-acting hydraulic cylinder with a relatively large driving face and a relatively small counterface on its driving piston, a direction- and- motion-control valve is provided in the form of a follow-up control valve which operates with electrically controllable desired position value stipulation and mechanical actual position value feedback. The pressure supply unit provides two supply pressures PN and PH of different magnitude. A pressure-controlled pressure changeover valve is provided which switches over to high supply pressure as required if the load increases. Also provided is a face changeover valve, likewise pressure-controlled, which, after the pressure changeover valve has switched over to higher supply pressure, switches over from differential operation of the hydraulic cylinder to pressurisation on one side of its piston, on the larger piston face of the latter, or, if the requirement for propulsive force has decreased again, after the pressure changeover valve has for this reason switched back to lower supply pressure, for its part switches back to differential operation of the hydraulic cylinder. <IMAGE>
IPC 1-7
IPC 8 full level
B21D 28/00 (2006.01); B21D 28/24 (2006.01); B21J 9/12 (2006.01); B21J 9/20 (2006.01); B30B 1/34 (2006.01); B30B 15/16 (2006.01); B30B 15/18 (2006.01)
CPC (source: EP US)
B21D 28/002 (2013.01 - EP US); B21J 9/20 (2013.01 - EP US); B30B 15/16 (2013.01 - EP US); B30B 15/161 (2013.01 - EP US)
Designated contracting state (EPC)
AT BE CH DE ES FR GB GR IT LI NL SE
DOCDB simple family (publication)
EP 0339247 A1 19891102; EP 0339247 B1 19930811; AT E92804 T1 19930815; BR 8901797 A 19891128; DE 3814580 A1 19891109; DE 58905209 D1 19930916; ES 2043923 T3 19940101; JP H01299800 A 19891204; JP H0696200 B2 19941130; US 5042362 A 19910827
DOCDB simple family (application)
EP 89104861 A 19890318; AT 89104861 T 19890318; BR 8901797 A 19890414; DE 3814580 A 19880429; DE 58905209 T 19890318; ES 89104861 T 19890318; JP 9329989 A 19890414; US 33822389 A 19890414