Patent ID: 8826764

Claim:
A braking device for a rotating shaft, the braking device comprising: a) a brake subassembly; and b) a sleeve, the sleeve being a hollow cylinder and comprising a cylindrical outer surface; wherein: the rotating shaft is sheathed with the sleeve; the brake subassembly comprises an adjustable screw, a spring, and a brake disc; one end of the spring presses on the top of the brake disc and the other end presses at the bottom of the adjustable screw; a bottom surface of the brake disc is a concave arc; the concave arc matches the cylindrical outer surface to allow the bottom surface to fit the cylindrical outer surface over an entire area of the bottom surface; after the adjustable screw is fixed, the bottom surface of the brake disc is tightly against the cylindrical outer surface of the sleeve to form a close contact with the cylindrical outer surface of the sleeve over the entire area of the bottom surface; when the adjustable screw is adjusted, the amount of compression of the spring is changed and the pressure imposed on the brake disc by the spring varies accordingly, so that the friction between the brake disc and the sleeve is changed; and when the bottom surface wears down due to the friction between the brake disc and the sleeve, the spring pushes the brake disc to be in the close contact with the cylindrical outer surface of the sleeve.