Back to results
US 6,978,609 B2Granted
Electrohydraulic servo door drive for operating a door, a window, etc.
AssigneeDorma GmbH + Co. KG
InventorSvan Busch
Life of this patent
Estimating the term…
Abstract
The invention pertains to an electrohydraulic servo door drive for operating a door, a window, or the like, with a hold-open function, where a valve is installed in the hydraulic circuit to implement the hold-open function. To create an electrohydraulic servo door drive which requires less space and can be produced at lower cost, it is provided according to the invention that the valve is designed as a hydraulically controlled hold-open valve.
Claims21
A door operator, comprising:
- a door operating element;
- a piston coupled to the door operating element and movable in a cylinder so as to define first and second cylinder chambers formed at respective opposite piston ends;
- a spring mounted in the second cylinder chamber and biasing the piston towards the first cylinder chamber so as to have the door operating element hold a door closed;
- an electrohydraulic servo drive comprising a hydraulically controlled hold-open valve configured with a 2/2-way directional lockable non-return control valve operable for displacing the piston towards the second cylinder chamber so as to have the door operating element hold the door open.
1 more element
Dependencies are inferred from the claim text.