Patent ID: 7222874
Filing Date: 2007-05-29
Classification: B60T,B62B,B62L,F16D

Abstract:
1. A rear wheel synchronous brake system installed in a pushcart having two rear wheels for operation by hand to stop said rear wheels, the rear wheel synchronous brake system comprising two rear brakes adapted to brake said rear wheels respectively, a hand control unit mounted on a top side of a handle of said pushcart, and two brake lines respectively connected between said hand control unit and said rear brakes, said brake lines each having a steel wire controllable by said hand control unit to move said rear brakes to brake said rear wheels synchronously, said rear wheels each having a hub, a wheel axle mounted in said hub and supported in an axle hole in one of two axle holders at two ends of a rear wheel holder of said pushcart, wherein said rear brakes are controlled by said hand control unit to brake the brake shafts of the hubs of said rear wheel synchronously, each comprising: a base block, said base block having a bottom wall, a peripheral wall perpendicularly extending around the border of said bottom wall, a mounting hole formed in said bottom wall and pivoted to said rear wheel holder of said pushcart, a coupling hole formed in said bottom wall remote from said mounting hole and coupled to one axle holder of said rear wheel holder of said pushcart, and a side hole cut through said peripheral wall; a locating frame, said locating frame having one side thereof fastened to a top side of the peripheral wall of said base block with a hollow screw and a nut, said hollow screw guiding the steel wire of one of said brake lines to the inside of said base block; a brake shoe shaped like a split ring, said brake shoe having a first end fastened to said bottom wall of said base block and a second end; a link, said link having a first arm fastened to one end of the steel wire of one of said two brake lines, a second arm fastened to the second end of said brake shoe, a middle connecting portion joining one end of said first arm and one end of said second arm, and a pivot hole cut through said middle connecting portion and pivotally connected to the mounting hole of said base block; and a torsional spring, said torsional spring having a first end hooked on said locating frame and a second end hooked on the first arm of said link.