Abstract: An absolute encoder monitors rotary position and senses rotary displacement relative to a measuring scale. The absolute encoder evaluates rotary displacement by providing a plurality of rotatably mounted encoder wheels, and each wheel includes at least one code sequence which in combination comprises the measuring scale. A pinion is provided between each pair of encoder wheels in order that each of the encoder wheels will be rotated upon the rotation of the shaft. Each code sequence of the encoder wheel is monitored by a sensing mechanism and this information is utilized to evaluate the shaft position. The sensing mechanism includes both light emitting and light detecting devices which monitor a defined region of each code sequence and this is evaluated in determining the rotary position.

Abstract: A valve actuator differential worm planetary gear drive provides forward or reverse motion to a valve stem, from an input from either a motor-driven worm or a handwheel drive worm, by using a plurality of planet gears to send motion to the sun gear. If the preference is to have the motor drive the valve primarily, the manual worm stays locked and the motor worm acts as a planetary arm. When it is desired to move the valve by hand, the motor gear is fixed and rotation of the handwheel worm gear transmits the power through the ring gear and the planet gears to the drive sleeve.

Abstract: A valve actuator differential worm planetary gear drive provides forward or reverse motion to a valve stem, from an input from either a motor-driven worm or a handwheel driven worm, by using a plurality of planet gears to send motion to the sun gear. If the preference is to have the motor driven the valve primarily, the manual worm stays locked and the motor worm acts as a planetary arm. When it is desired to move the valve by hand, the motor gear is fixed and rotation of the handwheel worm gear transmits the power through the ring gear and the planet gears to the drive sleeve.

Abstract: A device is described for supporting a nuclear fuel rod in a fuel rod assembly which allows the rod to be removed without disturbing other rods in the assembly. A fuel rod cap connects the rod to a bolt which is supported in the assembly end fitting by means of a locking assembly. The device is designed so that the bolt is held securely during normal reactor operation yet may be easily disengaged and the fuel rod removed when desired.