Stabilized reclining wheelchair seat

A wheelchair seat unit for retrofitting a motorized wheelchair having a base framework structure, the base framework structure having a forward and rearward end portion and a pair of drive wheels rotatably mounted near the rearward end and a pair of caster wheels rotatably mounted near the forward end, each of said drive wheels being drivingly connected to a separate electric drive motor and an electrical energy source mounted in a lower portion of said base framework structure, control means being mounted so that the user can control the rotation of the drive wheels to controllably move said wheelchair, the chair seat unit comprising:

• a) a slidable seat support means, said support means being fixedly attached to an upper portion of said base framework structure, said support means having a rail means aligned with an axis extending in the forward and rearward direction of said base structure and a seat support bar slidably mounted on said rail means whereby said seat support bar can be slidably moved along said axis;
• b) an integral seat unit having a seat portion and a back portion, said seat and back portion being joined together at a common edge in a substantially fixed angular position, said seat unit including attached arm rests, leg rests, and head rest for comfortably supporting the user;
• c) cam means including a pair of slotted plates and a pair of stanchions having a cam follower pin mounted at one end of each stanchion, said follower pin being sized to slidably fit a slot provided in a corresponding slotted plate;
• d) drive means having one end attached to said base framework structure and an opposite end attached to said slidable seat support means, said drive means including an electric drive motor which is electrically connected to said energy power source and a control means whereby the user can selectively move said seat support means to various positions along said axis between said drive and swivel wheels;
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• e) said integral seat unit includes a pivotal mounting means which attaches the seat unit adjacent to said seat common edge to said seat support means, said cam means slotted plates being fixedly attached to each side of the back portion of said seat unit near said common edge, said stanchions being fixedly mounted one each side of said base structure near the rearward end portion of said structure so that the stanchion cam follower pins engage the slots in said cam plates whereby as the seat unit is moved by the seat support means and drive means the seat unit is caused to angularly tilt from an upright position to a reclining position while maintaining the center of gravity of the chair and user between the wheels of the wheelchair to provide a stable and safe condition.

An assembly kit for retrofitting a wheelchair having a base framework structure having a forward end and a rearward end position, a pair of drive wheels being rotatably mounted near one end of said structure and a pair of caster rotatable wheels mounted at the opposite end of said structure, said assembly kit including:

• a) a seat unit having a back portion and a seat portion, said back and seat portions being fixedly attached at a common edge so that the relative angle between the back and seat portions are relatively fixed, said seat unit including leg rests, arm rests and a head rest which are adjustably positioned to provide maximum comfort for the user;
• b) a slidable seat support means mounted on an upper portion of said base framework structure and including a pair of cross members and a pair of seat guide rails, said seat guide rails are arranged parallel to each other and rigidly mounted between said cross members, said cross members being fixedly attached to side rails provided on each side of said base structure with said cross members being spaced apart by said guide rails and positioned near the end of said structure closest to the rearward portion of said structure, said guide rails having a seat support bar positioned above the guide rails and arranged perpendicular thereto, said seat support bar being attached to said guide rails by pillow blocks which slidably mount said seat support bar to said guide rails to allow movement along said guide rails with a minimum of force;
• c) said seat support bar having mounting means for pivotally mounting said seat unit to the seat support bar, said seat unit being attached to said seat support bar near the common edge area of said seat unit;
• d) cam control means attached to the sides of said seat unit and said base framework structure whereby as said seat support bar and seat unit are moved towards the forward end of said structure the seat unit is caused to tilt to a reclining position, said cam means including a pair of slotted cam plates which are attached to each side of the back portion of said seat unit and a pair of stanchions having a cam follower pin attached at one end, said cam follower pin being sized to slidably fit within a slot provided within each of said slotted cam plates, said stanchions being fixedly attached to each side of the framework structure and adjacent said seat unit with said cam pins arranged to project inwardly towards said seat unit and engage the cam slotted plates;
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• e) a power drive means having control means, said power drive means being attached to the forward end of said framework structure with the opposite end connected to said seat support bar whereby as the drive means is actuated said support bar will be moved along said guide rails so that said seat unit will tilt backward to a reclining position as the seat portion is moved towards the forward end of said structure whereby the center of gravity of the user and modified wheelchair will remain substantially centrally positioned between the support wheels of said wheelchair to maintain the stability and safety of said wheelchair.