Patent ID: 8381883

Claim:
A wheelchair safety device comprising: a brake lever, a first link lever, a second link lever, a third link lever, a fourth link lever, an upper brake plate, a brake wheel, a lower brake plate, a parking wheel, and an angularly adjustable mounting plate; wherein one end of the first link lever, the second link lever, and the third link lever are respectively articulated at the brake lever, and another end of the first link lever and the second link lever are articulated with one end of the fourth link lever, while another end of the fourth link lever is articulated at the upper brake plate and another end of the third link lever is articulated at the lower brake plate; one end of the upper brake plate is articulated at the angularly adjustable mounting plate, and another end of the upper brake plate is provided with an axle on which the brake wheel is mounted, while one end of the lower brake plate is articulated at the angularly adjustable mounting plate, and another end of the lower brake plate is provided with an axle on which the parking wheel is mounted via an one-way bearing; wherein the fourth link lever drives the upper brake plate so as to make it pivot on an articulation point of the upper brake plate and the angularly adjustable mounting plate, while the third link lever drives the lower brake plate to make it pivot on an articulation point of the lower brake plate and the angularly adjustable mounting plate; wherein the brake wheel and the parking wheel respectively act on wheelchair tires.