Global Patent Index - EP 0979357 A2

EP 0979357 A2 20000216 - HYDROSTATIC DISPLACEMENT DRIVE FOR LIFTING AND LOWERING AND HOLDING LOADS, IN PARTICULAR FOR LIFTS

Title (en)

HYDROSTATIC DISPLACEMENT DRIVE FOR LIFTING AND LOWERING AND HOLDING LOADS, IN PARTICULAR FOR LIFTS

Title (de)

HYDROSTATISCHER ANTRIEB ZUM HEBEN UND SENKEN UND ZUM HALTEN VON LASTEN, INSBESONDERE FÜR AUFZÜGE

Title (fr)

SYSTEME DE COMMANDE HYDROSTATIQUE POUR FAIRE MONTER ET FAIRE DESCENDRE ET POUR MAINTENIR DES CHARGES, NOTAMMENT POUR DES ASCENSEURS

Publication

EP 0979357 A2 (DE)

Application

EP 98914771 A

Priority

  • CH 9800173 W
  • CH 100497 A

Abstract (en)

[origin: WO9849085A2] The invention relates to a hydraulic or pneumatic drive for lifting and lowering loads, in particular for lifts. It has a working cylinder (11) forming a pressure chamber (14) connected to a pressure fluid source (39) and subjected to a pressure fluid. It also has a lifting piston (1) tightly guided in the working cylinder and a guide rod (15) arranged in the working cylinder. The guide rod (15) projects into the interior of the lifting piston (1) which tightly encloses the guide rod (15). The end (4) of the lifting piston (1) which projects into the pressure chamber (14) forms an annular face (5) which is subjected to pressure fluid. The interior of the lifting piston (1) forms an additional pressure chamber (7) subjected to pressure fluid and which is connected to its own pressure fluid source (40). The pressure fluid source connected to the working cylinder (11) delivers pressure fluid at a substantially constant pressure, whereas the pressure fluid source (49) connected to the additional pressure chamber (7) delivers pressure fluid at a variable pressure. The additional pressure chamber (7), subjected to pressure fluid, subdivides the total force needed to lift a load into two partial forces, one of which acts upon the annular face and the other in the interior of the lifting piston, close under the load. In this way, the partial force acting upon the entire length of the lifting piston and subjecting the piston to buckling is substantially reduced. It is thus possible to reduce the amount of material required without affecting buckling resistance.

IPC 1-7

F15B 11/036; B66B 1/04

IPC 8 full level

B66B 9/04 (2006.01); F15B 11/16 (2006.01); F15B 15/14 (2006.01)

CPC (source: EP)

B66B 9/04 (2013.01)

Citation (search report)

See references of WO 9849085A2

Designated contracting state (EPC)

AT CH DE ES FR GB IT LI PT

DOCDB simple family (publication)

WO 9849085 A2 19981105; WO 9849085 A3 19990211; AT 233374 T 20030315; AU 6916998 A 19981124; BR 9809430 A 20001114; CH 689211 A5 19981215; CN 1096577 C 20021218; CN 1255959 A 20000607; DE 59807321 D1 20030403; EP 0979357 A2 20000216; EP 0979357 B1 20030226; ES 2189153 T3 20030701; JP 2001527497 A 20011225; PT 979357 E 20030731; TR 199902647 T2 20000321; US 6422349 B1 20020723

DOCDB simple family (application)

CH 9800173 W 19980428; AT 98914771 T 19980428; AU 6916998 A 19980428; BR 9809430 A 19980428; CH 100497 A 19970430; CN 98804673 A 19980428; DE 59807321 A 19980428; EP 98914771 A 19980428; ES 98914771 T 19980428; JP 54645198 A 19980428; PT 98914771 T 19980428; TR 9902647 T 19980428; US 43205999 A 19991029