EP 0311779 A3 19900425 - HYDRAULIC CONTROL SYSTEM FOR A PRESS
Title (en)
HYDRAULIC CONTROL SYSTEM FOR A PRESS
Publication
Application
Priority
DE 3734329 A 19871010
Abstract (en)
[origin: EP0311779A2] A hydraulic control system (10) for a press having a rapid-motion cylinder (11) and a pressing cylinder (12) is proposed which, in combination with a high number of strokes and with cylinders (11, 12) operated in closed hydraulic circuits (34, 35), keeps the energy losses, and thus the oil heating, as low as possible. For this purpose, cylinders (11, 12), whose respective piston surfaces (15, 16, 17, 18) are the same size, are used of which at least the rapid-motion cylinder (11) is operated in a closed hydraulic circuit (34) having a highly dynamic, reversible control pump (24) as the actuating member, so that structural elements which produce energy losses, such as accumulators and servo valves, are dispensed with in the power circuit. Oil in the closed circuit (35) of the pressing cylinder (12), which is prestressed to a high system pressure, is circulated upwards and downwards during rapid feed movements and the lower piston chamber (23) in the pressing cylinder (12) is relaxed in a controlled manner via a pressure-limiting valve (48) only during pressing, energy from the decompression operation being used for the build-up of pressing power which is carried out by the control pump (24) in that the two cylinders (11, 12) are connected in parallel during pressing by means of a reversed directional control valve (36). Heat due to energy losses is removed as a result of oil exchange controlled by throttle valves (75, 87). <IMAGE>
IPC 1-7
IPC 8 full level
B30B 15/16 (2006.01)
CPC (source: EP)
B30B 15/161 (2013.01)
Citation (search report)
- [Y] US 3818801 A 19740625 - KIME J
- [Y] FR 2386414 A1 19781103 - SMG SUEDDEUTSCHE MASCHB [DE], et al
- [A] US 2913879 A 19591124 - CAMERON DONALD J
- [A] US 4524582 A 19850625 - LUCAS DELBERT E [US], et al
- [A] DE 229149 C
- [A] DE 198281 C
- [A] FR 1006287 A 19520421 - METROPOL CONSTRUCTION
- [A] WERKSTATT UND BETRIEB, Band 105, Nr. 8, August 1972, Seiten 613-616; K. HÖGEMANN et al.: "Hydrostatische Antriebssysteme für hydraulische Pressen"
Designated contracting state (EPC)
CH DE FR IT LI
DOCDB simple family (publication)
EP 0311779 A2 19890419; EP 0311779 A3 19900425; EP 0311779 B1 19931027; DE 3734329 A1 19890420; DE 3885228 D1 19931202
DOCDB simple family (application)
EP 88114159 A 19880831; DE 3734329 A 19871010; DE 3885228 T 19880831