Abstract: A modular power drive wheelchair is provided for rapid assembly and/or disassembly of relatively compact modular components. The wheelchair comprises a base module including a base frame and related support wheels, wherein the base frame is adapted for facilitated mounting or dismounting of a seat module. A battery module including at least one storage battery is provided for relatively easy slide fit mounting onto the base frame at a position below the seat module. A controller module is also provided for mounting onto the base module and functions during wheelchair operation to control battery powered operation of one or more drive motors coupled to the wheelchair wheels. The various modules are designed for rapid disassembly to permit easy transporting of the wheelchair, for example, within the trunk of a standard automobile. Moreover, the base and seat modules are designed for relatively easy size adjustment to accommodate changing size requirements, for example, of a growing child.

Abstract: An improved wheelchair is constructed with a base frame formed from composite material tubing. The base frame comprises a pair of unitary side frames of composite material tubing which preferably has an elliptical cross section oriented to provide increased structural strength along a primary loading axis during normal use. The side frames are interconnected by a plurality of cross braces of composite material tubing, wherein the lengths of the cross braces can be selected in accordance with a desired wheelchair frame width. A folding seatback is mounted on the side frames for releasable locking in an upright orientation, with a pair of spring-loaded lock pins being releasable by pulling a pull cord to permit seatback folding to a collapsed condition.

Abstract: An improved camber sleeve assembly is provided for rotatably supporting the main or large rear wheels on the frame of a wheelchair or the like. The camber sleeve assembly comprises a camber plate adapted for connection to the wheelchair frame at one side thereof. A pair of camber sleeve members are mounted in aligned relation at opposite sides of the camber plate and cooperatively define an angularly set bore for receiving and supporting an axle bushing at a selected chamber angle, with the axle bushing being adapted in turn to receive an axle pin of a wheelchair wheel. An alternative camber angle can be obtained by use of a different pair of sleeve members defining a bore set at the alternative angle.

Abstract: A modular power drive scooter, including as modular components a seat, a seat post, a mainframe, a trailer and at least one battery, is built in a manner allowing quick and easy disassembly of the scooter for compact storage. In assembled form, the seat post supports the seat and also serves as a lock pin which prevents separation of the mainframe from the trailer. The mainframe includes a front wheel, a tiller assembly for steering the scooter, and recesses for accommodating one or more batteries. The trailer includes a pair of rear wheels coupled to a differential which is driven by an electric motor, and a removable storage tray that provides access to the motor. A stem member extending from the trailer engages the mainframe in an overlapping relation whereby apertures in the stem member align with ports in the mainframe. The seat post is inserted into a selected port to determine the spacing of the seat from the tiller assembly.

Abstract: An improved caster wheel assembly for a wheelchair or the like includes adjustable bearing components for variably resisting swivel motion of a caster wheel to prevent undesired wheel flutter. The caster wheel assembly includes a wheel fork unit having a rotatable caster wheel, and a housing sleeve adapted for mounting onto the frame of a wheelchair or other castered device. An upstanding swivel post on the wheel fork unit is supported within the housing sleeve by the bearing components for rotation about an upright swivel axis. The bearing components include an outer bushing mounted on the housing sleeve, and having a conical bearing surface for axially engaging a mating bearing surface of a longitudinally split inner bushing. A nut threaded onto the swivel post urges the inner bushing axially against the outer bushing with a selected adjustable axial load to resist rotation of the swivel post, and thereby resist undesired rotational flutter of the swivel post and the associated caster wheel.

Abstract: A modular power drive wheelchair is provided for rapid assembly and/or disassembly of relatively compact modular components. The wheelchair comprises a base module including a base frame and related support wheels, wherein the base frame is adapted for facilitated mounting or dismounting of a seat module. A battery module including at least one storage battery is provided for relatively easy slide fit mounting onto the base frame at a position below the seat module. A controller module is also provided for mounting onto the base module and functions during wheelchair operation to control battery powered operation of one or more drive motors coupled to the wheelchair wheels. The various modules are designed for rapid disassembly to permit easy transporting of the wheelchair, for example, within the trunk of a standard automobile. Moreover, the base and seat modules are designed for relatively easy size adjustment to accommodate changing size requirements, for example, of a growing child.

Abstract: An improved pivot joint assembly is provided for use in the frame of a folding wheelchair or the like, wherein the pivot assembly provides a simple yet sturdy pivot interconnection between tubular frame members. The pivot joint assembly comprises a bearing of plastic or the like anchored within an open end of a first tubular frame member and defining an outwardly presented concave bearing seat, preferably of semi-cylindrical shape, for engaging the exterior of a second tubular frame member at a selected position intermediate the length of the second frame member. A strap bracket of generally U-shaped configuration is wrapped about the second frame member and secured by a lock pin or the like to the first frame member and to the bearing to retain the frame members in generally T-shaped relation with the first frame member pivotal about a central axis of the second frame member.

Abstract: An improved footrest unit is provided for use with a wheelchair or the like for supporting the foot and leg of a person using the wheelchair. The footrest unit includes an elongated leg tube having an upper end joined to an upper frame sleeve adapted for in-line rotatable connection between vertically aligned frame members of a wheelchair frame, and a lower end carrying a footplate for supporting the foot of a person using the wheelchair. The entire footrest unit is rotatable about a central axis of the frame sleeve and relative to the wheelchair frame for swinging movement between a normal operating position at the front of the wheelchair and an out-of-the-way position at one side of the wheelchair. Lock members are provided for releasably locking the footrest unit in the normal operating position. Two of the footrest units are normally provided for each wheelchair for respectively supporting both feet of a wheelchair user.

Abstract: A controller for a wheelchair motor or the like including two power transistors each having a base and a collector-emitter path, the collector-emitter paths being connected in parallel. At least one oscillator and a flip-flop are provided to supply pulses alternately to the transistor bases so that the transistors are never turned on simultaneously. In another system, two or more transistors are connected in parallel and are gated on in digital succession responsive to the outputs of a ring counter.

Abstract: A third caster wheel is mounted between the main wheels of a power wheelchair to engage the terrain over which the wheelchair travels. Turning of the wheelchair from a straight line course as a result of uneven terrain is immediately corrected by initially sensing the turning with the third caster wheel. A signal responsive to turning of the caster wheel stem is fed to the left and right wheelchair drive motors to increase the speed of one and decrease the speed of the other so as to return the wheelchair to its straight line course. The caster wheel sensing and feedback system is disabled when an intentional turning of the wheelchair is carried out with the conventional joy stick.

Abstract: The free-wheeling latch disengages the wheels of power type wheelchairs from the motors to permit easy manual use of the wheelchair. The latch itself is in the form of a manually movable pin projecting into a bore in the side of the hub. When the pin is moved inwardly, it engages a flange structure secured to the wheel axle and thereby locks the wheel to the axle for operation by the wheelchair motor. When the pin is manually retracted, the wheel and hub are free to rotate independently of the drive system to the axle.