Abstract: A wheelchair having a tubular frame comprising a pair of wheel-supporting, horizontally-disposed tubes clamped at their rear ends to upright posts for vertical adjustment of rear wheels mounted thereon. A pair of seat-supporting tubes pivotally connected at their rear ends to the upright posts, above the wheel supporting tubes, are also pivotally connected at their forward ends to links which are rigidly fixed at their lower ends to said wheel supporting tubes. Safety is improved by the rigid connections without significantly impairing the adjustment options.

Abstract: Adjustable wheelchair with a frame on whose sides the wheel axles of hand-driven rear wheels are mounted on mounts provided on the frame with a negative camber, i.e., closer together at top than at bottom. The mounts each have a mounting part in which there is an inclined bore hole holding the rear wheel axle in order to achieve the negative angle. The mounting parts 16 of the wheel axles 8 on both sides are arranged so they can rotate independently of each other in the respective mounts 6 and can be secured in any set rotational position. By releasing the mounts, the mounting parts can be rotated to change the direction of the rear wheels to eliminate toe-in or tow-out. Thus, any desired variation in the angle of the rear wheels is possible and/or any toe-in or toe-out tendency can be corrected.

Abstract: A collapsible wheelchair having a pair of opposed side frames connected by scissors cross bars and having a pair of vertical shafts, which terminate in handles connected to the rear end of the side frame. A pair of seat-supporting members telescope into the side frames and move up and down as the side frames are brought together to collapse the wheelchair. To reduce the frictional forces in the telescoping members, rollers are provided on the telescoping members which bear against the vertical shafts and roll up and down as the chair is folded from use to non-use positions and back again.

Abstract: A wheelchair having a pair of electrically driven drive wheels, a pair of power-operated swivel steering wheels which rotate about a vertical steering axis, and a manually-actuated lever. Each steering wheel has its own motor for adjusting the steering angle of the steering wheel. The steering lever connects to a mechanical-electrical steering angle generator which produces an electrical signal which is dependent on the angular position of the steering lever. The signal is fed into an electrical device which controls both steering wheel motors to adjust the steering angle of the steering wheels. The electrical device produces two adjustment signals, one for each wheel, which are inversely proportional to the radius of the turning curve. The steering angle can be set at any angle to up to 360.degree. thereby providing substantial maneuverability for the wheelchair.