Mechanical disc brake

A mechanical disc brake comprising:

• an inner caliper formed with circular hole and passed by pull cord fixing pin, two lateral faces of the circular hole being expanded to form circular dents, a transmission piston thread rod being disposed in one of the circular dents, a bottom face thereof being disposed with an adjustment thread rod and a lining assembly, a restoring spring being disposed in the other of the circular dents and connected with a brake lever;
• an outer caliper formed with opposite circular holes and passed by a locking bolt, a through hole being formed under the circular holes and fixed with a lining assembly by a C-shaped ring;
• a U-shaped bracket the free end of which is formed with connecting holes for the guiding bolt and fixing bolt to pass therethrough so as to connect with the inner caliper;
• and
• a brake lever, one end of the brake lever being formed with a socket, while the other end thereof being formed with an insertion hole, the socket being connected with the transmission piston thread rod, an orifice being formed beside the socket for one end of the restoring spring to fit therein, the insertion hole being pressed with a pull cord pressing board and passed by a locking bolt connected with a pull cord for controlling the brake, said disc brake being characterized in that:
• the transmission piston thread rod is formed with a thread hole for the adjustment thread rod to screw therein, a top end of the adjustment thread rod being fitted with a tightening nut, a bottom end thereof being connected with a lining assembly by a C-shaped ring, whereby when the brake lever is free from driving force of the pull cord, the lining assemblies are kept spaced from the brake disc by an optimal gap.