PURPOSE: To prevent wear and damage of a connecting portion by a simple method by providing a connecting control rod, which makes a distance between a clutch-armature and a brake-armature less than a predetermined value, and a sliding support which supports the rod.

CONSTITUTION: A non-magnetic connecting control rod 12 which controls a distance between a brake armature 9 and a clutch armature 4 less than a predetermined value is provided, and a sliding support 13 is contracted to support the connecting control rod 12. And the cut-off of the brake armature 9 and the connection of the clutch armature 4 are operated at same timing to prevent the simultaneous connection of a clutch and a brake. Accordingly, wear and damage of the connecting portion can be prevented by a simple method to make its life long.