Abstract: A wheelchair is provided that includes a motor-driven laterally extendable platform that can be extended and retracted to assist a user in getting onto and off of the wheelchair. A motor drive system is provided that can be actuated by an actuator. The actuator can be, for example, a wired remote controller or a wireless remote controller. Full actuation can be accomplished by a single triggering motion of the actuator, or the actuator can be configured to require a constant holding of the actuator until a desired position of the platform is reached. Travel limits can be programmed into the motor drive system such that the drive system stops driving extension or retraction of the platform once a travel limit is reached. The wheelchair can also be converted into a recumbent position. Methods of transferring a user onto or off of the wheelchair are also provided.

Abstract: A power wheelchair is capable of operating in either a two-wheel or a four-wheel drive configuration. The wheelchair includes first and second forward drive wheels in contact a supporting surface. First and second wheel support assemblies each include a support member pivotally connected to the wheelchair frame. Each wheel support assembly further includes a rear drive wheel and a rear non-driven wheel connected to the support member. At least one actuator is provided to control movement of the support members to pivot between a first position and a second position. In the first position, the rear non-driven wheel is moved into contact with the supporting surface and the rear drive wheel is moved out of contact with the supporting surface. In the second position the rear drive wheel is moved into contact with the supporting surface.

Abstract: A variable stiffness suspension system is provided for a wheelchair. The wheelchair has a frame and at least one wheel coupled to the frame for generally vertical movement relative to the frame. At least one sensor is provided for sensing an operating condition of the wheelchair. A controller is operatively coupled to the sensor. A controllable damper having a variable stiffness is coupled to the controller, the wheel and to the frame. The controllable damper is responsive to the controller and provides a force capable of being varied in a continuous manner. The force is resistive to movement of the wheel. The controllable damper is preferably a commercially available magneto-rheological damper or a variable orifice fluid damper. The controllable damper may be either a linear damper or a rotary brake.

Abstract: A reclining seat includes a base, a back frame and back support connected to the back frame for translation relative to the back frame. In a first embodiment, a mechanism is provided to couple the back frame to the back support such that rotation of the back frame relative to the base automatically translates the back support relative to the back frame. In a second embodiment, a mechanism is provided to allow a user to control movement of the back support independently of back frame rotation. Preferably, the reclining seat is incorporated into a wheelchair.

Abstract: A power wheelchair is capable of operating in either a two-wheel or a four-wheel drive configuration. The wheelchair includes first and second forward drive wheels in contact a supporting surface. First and second wheel support assemblies each include a support member pivotally connected to the wheelchair frame. Each wheel support assembly further includes a rear drive wheel and a rear non-driven wheel connected to the support member. At least one actuator is provided to control movement of the support members to pivot between a first position and a second position. In the first position, the rear non-driven wheel is moved into contact with the supporting surface and the rear drive wheel is moved out of contact with the supporting surface. In the second position the rear drive wheel is moved into contact with the supporting surface.

Abstract: A reclining seat includes a base, a back frame and back support connected to the back frame for translation relative to the back frame. In a first embodiment, a mechanism is provided to couple the back frame to the back support such that rotation of the back frame relative to the base automatically translates the back support relative to the back frame. In a second embodiment, a mechanism is provided to allow a user to control movement of the back support independently of back frame rotation. Preferably, the reclining seat is incorporated into a wheelchair.

Abstract: A lift mechanism for a wheelchair includes a parallelogram linkage and an actuator for moving the linkage between a retracted position and an extended position to raise and lower a chair. One link of the linkage is slidingly engaged with a rail member. Movement of the linkage is constrained by another link such that as the chair is raised and lowered, the longitudinal position of an occupant's center of gravity relative to the wheelchair frame is substantially maintained. The lift mechanism may be combined with a tilt actuator to allow rotation of the chair. A chair tilt mechanism is also provided having a tilt actuator, a first link slidingly engaged with a rail member and a second link constraining movement of the first link. The tilt mechanism is capable of tilting the chair while substantially maintaining the longitudinal position of the occupant's center of gravity.

Abstract: A variable stiffness suspension system is provided for a wheelchair. The wheelchair has a frame and at least one wheel coupled to the frame for generally vertical movement relative to the frame. At least one sensor is provided for sensing an operating condition of the wheelchair. A controller is operatively coupled to the sensor. A controllable damper having a variable stiffness is coupled to the controller, the wheel and to the frame. The controllable damper is responsive to the controller and provides a force capable of being varied in a continuous manner. The force is resistive to movement of the wheel. The controllable damper is preferably a commercially available magneto-rheological damper or a variable orifice fluid damper. The controllable damper may be either a linear damper or a rotary brake.