Instrumentation & controls manufactures rotary actuators, hydraulic or pneumatic, in a broad range of torque angles. Torque angles exceeding 120° are not readily available with conventional cylinder and pivot, lever arrangements. These can be available with torque cylinders offering fully rotary operations. Two directly opposed cylinders are fitted to a central mounting block included in the rotary actuators and a high gauge slotted piston rod passed through the block helps to unite the two associated piston heads. The slot in the piston rod contains toothed rack [machined in it], which engages with the teeth of a pinion. The pinion and its shaft are constructed in one piece or connected together and are supported by bronze bearings located in the mounting block of the pneumatic rotary actuators. Both ends of the shaft are projected out from the block. When pressure is exercised on one of the pistons, power is transmitted via rack and pinion to the shaft; thus the linear motion of piston and rack is transformed to rotary motion of pinion and a shaft. The angle through which the shaft of the rotary actuators rotates is dependent upon the length of stroke of the piston. Rotation of the shaft occurs in the opposite direction when pressure is applied to the opposing piston. Torque momentum developed by the rotary actuators is dependent upon applied feed pressure, which may be varied as per requirement. These rotary actuators are available for various torque angles from 60° to 360°. The torque varies with different models of the rotary actuators, up to 30,000 in-lb at 1,500 psi oil pressure in hydraulic actuators and 15,000 in-lb at 100 psi air pressure in pneumatic actuators.
