PURPOSE: To eliminate deflection and inclination of the turning movement of an operating lever to operate it smoothly by providing a tapered inner peripheral surface radially inclined inward and axially directed outward to the cylindrical part of a brake cover, providing a tapered outer peripheral surface radially inclined outwardly to the inside cylindrical part of an operating lever, and combining the inner and outer peripheral surfaces slidably and rotatably.

CONSTITUTION: One end of a brake cover 21 is mounted to the side plate 1b of a body 1, and a cylindrical part 24 is formed at the other end part. The cylindrical part 24 is tapered so that it is narrowed outward, and its inner peripheral surface 24a is formed into a tapered inner peripheral surface inward inclined outwardly. An inside cylindrical part 28 supported on the cylindrical part 24 of the brake cover is provided to the inside cover 26a of an operating lever 6. After insertion, the cylindrical part 28 is tapered so that it expands inwardly, and its outer peripheral 28a is formed into a tapered outer peripheral surface inclined outwardly. The tilt angle of 28a is taken to be larger than that of the tapered inner peripheral surface 24a so that both the surfaces can slide and rotated each other. For the operating lever 6, loads in the radial and axial directions are thus received by the cover 21, and thereby deflection and inclination can be prevented.