Fluid activated load operator

Abstract

A door operator includes a double acting power cylinder with a dual metering valve mounted thereon. The valve unit includes an external tube with a sliding control piston coupled to the power cylinder for corresponding selected movement. A pair of spaced metering assemblies are secured to the tube and each includes a supply-exhaust port connected through a four-way valve means to an air supply and an exhaust, and connected to provide air flow to and from opposite end heads of the power cylinder. Each assembly has a one-way supply passageway, a central speed control passageway and a fixed damping passageway. The latter two passageways each have a small needle valve control and the speed control passageway is selectively blocked by the control piston. The power and damping cylinder assembly includes a mounting enclosure with the controls therein and with the power cylinder piston rod pivotally connected to a tubular drive arm. An adjustable excursion rod adjustably telescopes into the drive arm and in turn is pivotally interconnected to a second positioning rod. A pivotal mounting bracket is adjustably secured to the outer end of the positioning rod for attachment to the door. The linkage adapts the operator to various sizes and types of doors, with a special positioning rod and angle drive arm provided for swinging doors. A ratcheting relay control unit is coupled to control the solenoid valve in response to actuation of any one of a plurality of interconnecting control and/or safety switches.