Electro hydraulic door drive has a permanently pressurized reservoir for emergency closure

摘要

An improved electro hydraulic door drive has a hydraulic pump to open and close the door and a pressurized reservoir which is pressurized only once and which is kept at pressure without affecting the door drive. This ensures that the door drive only has the overcome friction while the reservoir is available for emergency closure of the door. The reservoir is pressurized separately to the door drive enabling a smaller pump to be fitted. A simple design has a spring tensioned by a hydraulic drive and held n the tensioned state by a locking system.