Patent ID: 7516984
Filing Date: 2009-04-14
Classification: A61G,Y10S

Abstract:
1. A jointed mechanism of an electric wheelchair, the jointed mechanism comprising: a main chassis assembly, supporting the electric wheelchair; two drive wheel assemblies, providing a motive force for moving the electric wheelchair; two rear caster assemblies, pivotally fixed to the drive wheel assemblies, and bushed to the main chassis assembly by pivot arm plate assemblies; and two front caster assemblies, bushed to the main chassis assembly and the rear caster assemblies to construct a four-bar linkage, wherein each of the front caster assemblies comprises a front caster anti-tip wheel, a caster wheel fork and a front caster arm; each of the rear caster assemblies comprises a rear caster wheel, a caster wheel fork and a rear caster arm; and each of the drive wheel assemblies comprises a drive wheel and a motor/gearbox/brake assembly, and wherein the front caster assemblies are bushed to the main chassis assembly at the front caster arms; the rear caster assemblies are pivotally attached to the main chassis assembly at the rear caster arms; the front caster arms and the rear caster arms are hinged to each other; and the motor/gearbox/brake assemblies are mounted to the rear caster arms, wherein each of the front caster arms comprises a straight part, which is backward extended, and an angled part, which is extended from the straight part and bent downward; each of the rear caster arms comprises a straight part and two angled parts extended from opposite ends of the straight part and bent downward, and wherein the front caster arms and the rear caster arms are hinged to each other at the ends of the angled parts and are bushed to the main chassis assembly at the straight parts, wherein the straight parts of the front caster arms and the straight parts of the rear caster arms comprise pivot arm bushing assemblies, respectively; the angled parts of the front caster arms and the angled parts of the rear caster arms comprise hinged apertures at ends thereof, respectively; and the main chassis assembly comprises two front caster arm axles and two rear caster arm axles, and wherein the front caster arm axles are received in the pivot arm bushing assemblies on the straight parts of the front caster arms; the rear caster arm axles are received in the lower ends of the pivot arm plate assemblies; and the upper ends of the pivot arm plate assemblies are bushed to the pivot arm bushing assemblies on the straight parts of rear caster arms.