Abstract: An improved pump for providing pressurized fluid to a pressurized fluid operating device for opening and closing a door comprising having a pump housing with a pump chamber therein; a rotatable pumping element within the pump chamber; a pair of passages adapted for connection to a pressurized fluid operating device extending from the pump chamber to the exterior of the pump housing; means for driving the pump element in rotation; and a pair of pressure responsive bypass valves. The pump element is adapted to deliver pressurized fluid to either one of the pair of passages as determined by the sense of rotation of the pump element, with the other passage receiving the exhaust flow of pressurized fluid. Each of the pressure responsive bypass valves is connected to a different one of the pair of passages in the pump housing and is adapted to bypass pressurized fluid at a predetermined pressure setting.

Abstract: An improved pump for providing pressurized fluid to a pressurized fluid operating device for opening and closing a door comprising having a pump housing with a pump chamber therein; a rotatable pumping element within the pump chamber; a pair of passages adapted for connection to a pressurized fluid operating device extending from the pump chamber to the exterior of the pump housing; means for driving the pump element in rotation; and a pair of pressure responsive bypass valves. The pump element is adapted to deliver pressurized fluid to either one of the pair of passages as determined by the sense of rotation of the pump element, with the other passage receiving the exhaust flow of pressurized fluid. Each of the pressure responsive bypass valves is connected to a different one of the pair of passages in the pump housing and is adapted to bypass pressurized fluid at a predetermined pressure setting.

Abstract: An improved hydraulic door actuator comprising a hydraulic fluid pump having first and second ports; integral operating cylinder and fluid control apparatus including a barrel coupled at each end to the first and second ports of the hydraulic fluid pump; a piston fluidly sealed within the barrel; and means for controlling the flow of fluid of the hydraulic fluid pump to and from the barrel disposed between the barrel and the first and second ports such that the door automatically slows to a stop upon opening or closing wherein the fluid flow control means comprises a plurality of openings disposed along the length of the barrel for bypassing pressurized fluid from the barrel.

Abstract: A hydraulic door opening or closing device comprises a hydraulic fluid pump motor having two ports connected to each end of integral dual manifold and operating cylinder apparatus by way of two branch fluid lines. One branch line is fluidly connected to a particular end of the operating cylinder by way of a directional flow valve. The other branch line to the same end of the cylinder is fluidly connected to the cylinder by way of an associated manifold. Fluid communication with the cylinder through the manifold is accomplished by providing a plurality of valved openings linearly disposed along the end of the cylinder between the manifold and the cylinder. As a piston of the operating cylinder passes these openings, a door coupled to the piston is automatically slowed as fluid on the drive side of the piston is returned through the openings to the hydraulic fluid pump.