Patent ID: 8905420

Claim:
A wheelchair comprising: two opposing frontmost ground-engaging wheels and a single rear castor having a ground engaging wheel thereon, the frontmost ground-engaging wheels having a substantially greater diameter than the rear ground-engaging wheel and are axially opposed to each other on opposite sides of the user seat, such that the user may propel the wheelchair by action of his hands on the frontmost ground-engaging wheels; and a user seat with a backrest together forming a single structural member on which the ground-engaging wheels are supported; wherein said rear castor is positioned centrally behind the user seat and is connected to the backrest by a gas spring, the length of the gas spring being adjustable during use; and wherein the wheelchair further comprises means for altering the length of the gas spring, to lower or raise the backrest of the user seat to vary the angle of the backrest such that the center of gravity of the wheelchair is altered, said means for altering the length of the gas spring comprising means for locking the gas spring at an adjusted length, the means for locking the gas spring being releasable, for adjusting the length of the gas spring while released.