摘要 |
An apparatus (10) is disclosed including a friction clutch (12) and an overload apparatus (14) connected in parallel between an input (16) and an output (18). Encoders (20, 22) are provided for separately detecting the rotational positions of the input (16) and the output (18). A microcomputer controller (580) controls actuation of the friction clutch (12) and the overload apparatus (14) in response to the rotational positions detected by the encoders (20, 22) allowing the clutch (12) to bring the output (18) to be generally aligned with a select rotational position of the input (16) at which time the overload apparatus (14) can be actuated to rotatably relate the input (16) and the output (18) at the select rotational position and actuation of the clutch (12) can be removed. The microcomputer controller (580) also removes actuation of the overload apparatus (14) when the encoders (20, 22) detect rotation of the input (16) relative to the output (18) from the select rotational position. In the most preferred form, the encoders (20, 22) include codewheels (500, 501) rotatable with the input (16) and the output (18), respectively, and relative to slotted optical switches (502-505), with the codewheels (500, 501) including 64 evenly spaced slots which rotate past the slotted optical switches (502-505). |