Patent ID: 7367432
Filing Date: 2008-05-06
Classification: B62B

Abstract:
1. A brake device for a pushcart, the pushcart having a cart frame and a pair of aligned first and second wheels, said brake device comprising: a hollow main seat adapted to be disposed fixedly on the cart frame and in proximity to the first wheel; a main movable member disposed movably within said main seat and movable between upper and lower limit positions; a main biasing member for biasing said main movable member to said upper limit position; a main positioning unit for holding said main movable member at said upper and lower limit positions; a hollow auxiliary seat adapted to be disposed fixedly on the cart frame and in proximity to the second wheel; an auxiliary movable member disposed movably within said main seat and movable between first and second positions; an auxiliary biasing member for biasing said auxiliary movable member to said first position; an auxiliary positioning unit for holding said auxiliary movable member at said first and second positions; a connecting member interconnecting said main and auxiliary movable members such that movement of said main movable member from said upper limit position to said lower limit position results in movement of said auxiliary movable member from said first position to said second position, and such that movement of said main movable member from said lower limit position to said upper limit position results in movement of said auxiliary movable member from said second position to said first position; a main brake mechanism adapted to be disposed between said main seat and the first wheel and including a main pin-engaging member that is adapted to be connected fixedly to the first wheel and that is formed with a plurality of grooves, and a main brake pin connected to said main seat and said main movable member so as to engage one of said grooves in said main pin-engaging member when said main movable member is disposed at said lower limit position, and so as to disengage from the one of said grooves in said main pin-engaging member when said main movable member is disposed at said upper limit position; and an auxiliary brake mechanism adapted to be disposed between said auxiliary seat and the second wheel and including an auxiliary pin-engaging member that is adapted to be connected fixedly to the second wheel and that is formed with a plurality of grooves, and an auxiliary brake pin connected to said auxiliary seat and said auxiliary movable member so as to engage one of said grooves in said auxiliary pin-engaging member when said auxiliary movable member is disposed at said second position, and so as to disengage from the one of said grooves in said main pin-engaging member when said main movable member is disposed at said first position. wherein said main positioning unit includes: a cam groove portion formed on an outer surface of said main movable member and having first, second, third and fourth slanting surfaces, and four inclined guiding surfaces, any two adjacent ones of said first, second, third and fourth slanting surfaces being interconnected by a corresponding one of said inclined guiding surfaces; and a resilient lock pin having a mounting end mounted to an inner surface of said main seat, and an L-shaped insert end engaging said cam groove portion, said lock pin being guided by said inclined guiding surfaces to move on said cam groove portion along a predetermined direction such that said main movable member can be pressed downwardly to move from said upper limit position to said lower limit position and from said lower limit position to said upper limit position, said lock pin engaging said first slanting surface when said main movable member is disposed at said upper limit position, said lock pin engaging said second slanting surface when said main movable member is disposed at said lower limit position.