Mechanism for quickly adjusting tightness of brake cable in caliper brake of bicycle

A caliper brake of a bicycle comprising:

• a first arm;
• a cable housing disposed at an upper end of the first arm;
• a first brake pad affixed to a lower end of the first arm;
• a second arm pivotably secured to the first arm and comprising a yoke at one end, the yoke comprising two opposite yoke arms having a hole, and a spring depressible detent disposed at one end of the second arm and between the yoke arms;
• a second brake pad affixed to the other end of the second arm;
• and
• a mechanism comprising a manipulation member rotatably disposed between the yoke arms, the manipulation member comprising a C-shaped element including a plurality of teeth formed on an outer surface thereof, and a protrusion formed on an inner surface proximate one end of the C-shaped element, and a handle projecting out of the C-shaped element to dispose between and externally of the yoke arms;
• a brake cable retaining member for retaining a brake cable passing the cable housing and comprising a projecting cylindrical member having internal threads;
• a cylinder comprising a plurality of spaced positioning recesses formed on an intermediate portion of an outer surface thereof, an eccentric tunnel through the cylinder, and a hole in communication with the tunnel, the hole having a diameter larger than that of the tunnel;
• and a fastener having a threaded shank,
• wherein the cylinder is substantially disposed in the yoke, the protrusion is lockingly engaged with one of the positioning recesses, the cylindrical member is fitted in the tunnel, the threaded shank is driven into the threads to secure the cylinder and the brake cable retaining member together, the handle is disposed below the yoke, the detent is urged against one of the teeth proximate the other end of the C-shaped element, the hole is disposed at its lowest position in the yoke, and the brake cable is held tight;
• and
• wherein in response to counterclockwise rotating the handle the hole disposes at a position higher than its lowest position in the yoke and both the detent moves to another one of the teeth and the protrusion moves to another one of the positioning recesses so as to loosen the brake cable.