Abstract:
A lightweight, easily maneuverable and transportable power chair, that may be manually propelled, includes a pair of freely rotatable wheels and a corresponding pairs of friction rollers and braking surfaces that are selectively engageable therewith to effect propulsion and steering of the chair. A pair of toggle levers are operated by a corresponding pair of control handles for selectively engaging the friction rollers and brake surfaces with the wheels. A single caster wheel is vertically rotatable at the front of the power chair frame. This forms a tricycle rolling system that always maintains a load on each of the driving wheels.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to mobile chairs and specifically to a power chair that is lightweight, capable of manual operation and easily transportable. 
     There are basically two types of mobile chairs; conventional, hand propelled wheelchairs and chairs that are powered (motorized), either by a battery or a gasoline engine. The term motorized as used herein is intended to apply to both battery power and engine power. Hand propelled wheelchairs have been manufactured for more than a century without significant changes in design. Generally hand rings are mounted adjacent to the large wheels to assist in propulsion by the user, although very often the wheel tires are grasped directly to propel the wheelchair. Such wheelchairs are satisfactory for indoor use where floors are usually flat and smooth. Outdoor operation on the other hand, presents challenging obstacles for a user. For example, soft ground and hills make it extremely difficult to travel with a hand propelled wheelchair. Therefore, some sort of powered wheelchair is considered very beneficial for outdoor use. 
     Most powered wheelchairs and powered scooters are battery driven and intended for outdoor as well as indoor use, but they are not suited to unpaved surfaces like grass, dirt and bumpy trails. The shopping cart scooter is the most popular and, while designed primarily for indoor use, it also sees limited outdoor service in transporting both the user and groceries across the store parking lot. Powered wheelchairs and scooters have been a boon to the handicapped and elderly. Most battery powered wheelchairs use two motors, left and right, each being associated with some form of reduction gearing. A joystick controls a fairly complicated electronic system for switching and modulating the requisite high current, low voltage, power. These arrangements are expensive and prone to service problems. 
     Scooters on the other hand, use only one motor which drives the wheels through a differential. While the costs and weight of a differential are about the same as an extra motor and gear reduction mechanism, the controls on the scooter are less complicated and the unit is generally more reliable than the two motor wheelchair. Steering of the front wheel of the scooter is accomplished with a small handlebar. Unfortunately, the scooters are not particularly maneuverable. These vehicles&#39; major drawbacks of bulk and weight (generally in the range of 150 to 200 pounds), have prevented their widespread acceptance and use despite their obvious great benefits for outdoor use. They also require special measures in order to transport them. 
     One serious drawback is that the motors drive the wheels through gearing which cannot be overdriven. Thus a drive failure, or a dead or defective battery, can leave the 200 pound vehicle frozen in place with its wheels effectively locked and the user helplessly stranded. Generally a van, which has a large door, rather than a passenger automobile, is required to transport them. The van is usually equipped with a power lift of some sort to enable the loading and unloading of the motorized powered chair or scooter. 
     The present invention provides a power chair that is lightweight, compact and maneuverable and therefore well suited to hand propulsion. The preferred embodimnent of the invention is directed to a powered wheelchair, but it will be apparent that the invention will find ready use as a safe, transportation vehicle for use by all ages, irrespective of any infirmity. It&#39;s lightweight and small size enables it to be transported by automobile or van without special equipment and its long range permits it to be used in the country for sightseeing and the like. 
     While the preferred embodiment incorporates a compact gasoline engine, it should be understood that the invention is not to be so limited. The particular compact gasoline engine used is a 4-cycle Honda® engine, which finds application in hand equipment such as electric generators, water pumps, chain saws and weed trimmers. The engine is much lighter than a comparably sized electric motor, and is much quieter and cleaner burning than the 2-cycle engines normally used in such equipment. Whereas most battery powered chairs weigh from 150 to 200 pounds, and a conventional hand propelled wheelchair weighs around 40 pounds, the powered wheelchair version of the invention weighs only 35 pounds. As will be seen, the inventive power chair also employs a comfortable, removable, padded rigid seat, which, when removed, enables the power chair to be transported in the trunk of a compact automobile. In contrast, conventional hand powered, transportable wheelchairs require a flexible sling type seat and back, which are not comfortable for the user. 
     As mentioned above, the power chair of the invention is readily transportable in the trunk of a compact automobile and is easily hand propelled, when indoors, because of its lack of bulk, extreme light weight and excellent maneuverability. The gasoline powered version of the inventive power chair is presently preferred since it exhibits a much greater range of operation (approximately 45 miles per ½ gallon tank of gasoline) over a battery powered power chair of the same general design. Refilling the ½ gallon tank is also much faster and more convenient than recharging a battery from a household source of power. 
     Propulsion and steering of the inventive power chair is provided by selectively engaging the wheels with corresponding motor-driven friction rollers that are affixed to a rotatable drive axle. The engagement between the friction rollers and the wheels is controlled by a pair of manual control arms that the user moves forward for propulsion and backward for braking. This action is accomplished by a pivotally mounted rocker lever that carries a friction drive roller and a friction brake surface that are selectively engageable with the associated wheel. Normal turning is accomplished by engaging one friction roller with its corresponding wheel. Very tight turns may be made by simultaneously engaging one friction roller with its associated wheel and engaging the other brake surface with its associated wheel. Since the control arm arrangements are self centering, the wheels are normally in a free wheeling state. 
     In one version of the inventive power chair, provision is made for “hands free” steering through the use of a clutched drive lock system for holding both friction rollers in engagement with the wheels for forward propulsion. The clutched drive lock system also provides a “parking brake” to hold the power chair on inclined surfaces or to steady it for the user. The maneuverability of the inventive power chair derives from the transmission system discussed above and the provision of a front caster wheel that freely swivels in accordance with the directional forces developed by the wheels. The freely movable front caster wheel is also provided with a foot steering plate, generally for making slight steering corrections to compensate for road conditions and the like and is especially useful for hands free operation during relatively long distance travel, when the clutched drive lock system is engaged. As will be seen, the transmission system, including the motor, is movably supported on the power chair frame to permit the pivoting and translational movements of the drive axle. 
     OBJECTS OF THE INVENTION 
     A principal object of the invention is to provide a novel power chair. 
     Another object of the invention is to provide a compact lightweight, readily transportable power chair. 
     A further object of the invention is to provide a novel power chair of greatly improved range. 
     Still another object of the invention is to provide a novel powered wheelchair that may be hand propelled. 
     A still further object of the invention is to provide a more comfortable, easily transportable wheelchair. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and advantages of the invention will be apparent upon reading the following description in conjunction with the drawings in which: 
     FIG. 1 is a side elevation of the power chair of the invention; 
     FIG. 2 is a plan view of the power chair of FIG. 1 with the seat removed; 
     FIG. 3 is a partial isometric view of the power chair of the invention; 
     FIG. 4 is a partial plan view of the clutched drive lock arrangement; and 
     FIG. 5 illustrates the arrangement for enabling disabled persons to more easily dismount from the powered chair version of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings generally and to FIGS. 1 and 2 in particular, a power chair  10  includes a lightweight aluminum tubular frame  12 , to opposite sides of which a pair of wheels  20  and  22  are mounted for freewheeling rotation by a pair of stub axles  48  and  50 , respectively. Frame  12  has a generally Y shaped configuration that includes a rearwardly extending U shaped section (formed by two rear legs  14  and  16 ), and a forwardly extending front leg  18 . A rear frame member  17  is affixed to the ends of rear legs  14  and  16 . The wheels  20  and  22  are conventional bicycle-like wheels with pneumatic tires, A pair of hand rings  42  and  44  are attached to wheels  20  and  22 , respectively by a plurality of fasteners  46 . A front caster wheel  30  rotates on a vertically oriented axle  33  that is secured in a fork  31 . Fork  31  is rotatable in a hub  35  that is located at the end of front leg  18 . The three wheel arrangement is very stable and is especially beneficial when the power chair is used on non uniform surfaces, because each of the three wheels is always in contact with the ground. 
     A user foot rest  36  is supported forwardly of the end of front leg  18  by a pair of curved side supports  32  and  34  that are pivotally secured to front leg  18  by a pivot  37 . A contoured, relatively rigid seat  53  is secured to rear legs  14  and  16  of frame  12  by a pair of uprights, only one of which ( 19 ) is visible in the figures. Seat  53  is preferably readily removable to enable the power chair to be conveniently stowed in the trunk of a compact size automobile. Two small wheels  24  and  26  extend from the rear of frame  12  to limit the maximum elevation that caster wheel  30  may experience. These wheels are normally not operational unless caster wheel  30  is elevated to a height that could result in an unstable condition. 
     A steering and propulsion control arrangement includes a pair of manual control arms  38  and  40  which are substantially identical. Only control arm  38  will be described in detail. As best seen in FIGS. 1 and 3, control arm  38  comprises a lever arrangement that includes a handle  39 , a horizontal member  43  and a rocker lever  45 , which is secured to leg  14  of frame  12  by a pivot  51 . (The opposite side rocker lever is similarly secured to leg  16  by a pivot  61 .) Rocker lever  45  carries a brake surface  47  that is located above pivot  51  and which overlies the periphery of wheel  20 . Brake surface  47  may comprise any suitable material for frictionally engaging wheel  20 . A drive axle  70  passes through a bushing  80  that is flexibly mounted to rocker lever  45  below pivot  51 . Drive axle  70  is secured in a driven pulley  68  which is coupled, via a belt  72 , to a drive pulley  54  that is driven by a motor  52 . A friction roller  64  is secured to the end of drive axle  70  and rotates therewith. Friction roller  64  is engageable with the radial periphery of wheel  20  for imparting a rotational force thereto, whereas brake surface  47  is engageable with the radial periphery of wheel  20  for applying a braking force thereto. (It will be appreciated that the friction roller and brake surface may readily be arranged to engage other portions of wheel  20  and the invention should not be limited to engagement with the radial periphery of the wheel.) Similarly, a friction roller  66  is secured to the other end of the drive axle  70 . It will be appreciated by those skilled in the art that the friction rollers may comprise any well-known form of driver elements, such as gear wheels and the like, all within the spirit and scope of the present invention. 
     Drive axle  70  (and the attached driven pulley  68 ) is mounted for rotation in a tubular bearing member  62  that is affixed to one end of motor  52  by a pair of horizontally disposed supports  56  and  58 . Motor  52  is secured at its other end to frame member  17  through a rigid member  60  and a flexible member  74 , as best shown in FIG.  3 . Flexible member  74  may comprise a piece of hard rubber or the like. It will be appreciated that the motor and drive axle support arrangement forms a limited, floating power transmission unit that permits the slight movements required to rocker the friction rollers and brake surfaces into engagement with the corresponding wheels responsive to corresponding forward and backward movements of the handles  39  and  41 . 
     Operation is best described in connection with FIG. 3 where the elements of the power transmission unit are more clearly shown. When motor  52  is operating, it transmits rotary motion to drive axle  70  (and to the friction rollers  64  and  66 ) through drive pulley  54 , belt  72  and driven pulley  68 . The control arms  38  and  40  are self centering and, with no force applied to the handles  39  and  41 , there is no engagement between the radial peripheries of wheels  20  and  22  and either of the friction rollers  64  and  66 , or either of the brake surfaces  47  and  49 , respectively. Moving handle  39  forward causes rocker lever  45  to rotate slightly about pivot  51  and force friction roller  64  into driving engagement with wheel  20 . The slight angular displacement of drive axle  70  is accommodated by flexibly mounted bushing  80  and its corresponding opposite side flexible bushing, (not shown). Similarly, pulling on handle  39  results in brake surface  47  being forced into engagement with wheel  20 . Thus operation of handle  39  controls the propulsion and braking of wheel  20 . Similarly, forward and backward movements of the opposite handle  41  result in propulsion and braking of wheel  22 . For straight-ahead movement of the power chair, both handles  39  and  41  are pushed forward. For turns, only one of the handles is pushed forward. For very sharp turns, the handles are operated in opposite directions to propel one wheel and simultaneously brake the other wheel. The power chair is stopped by pulling back on both handles. 
     It will be appreciated that the power transmission unit or system floats on the frame by virtue of the two flexibly mounted bushings and the flexible motor support  74 . Caster wheel  30  is freely rotatable and orients itself to the directional movements generated by the wheels  20  and  22 . The wheels, which measure eighteen inches in diameter, are small enough so that the power chair, as discussed below, is able to fit within the trunk of a compact automobile. The handles  39  and  41  may be arranged to pivot with respect to horizontal member  43  to fold them down for stowage of the wheelchair. A simple spring-loaded pin and hole lacking arrangement would be suitable for this purpose. With the seat removed and the handles pivoted down, the wheel diameter is the largest vertical demension that needs to be accommodated by the transporting vehicle, which as indicated above may be a compact automobile. The foot platform  36  may also be rotated back about pivot  37  to reduce the length of the power chair for stowage or transport. The provision of wheel hand rings  42  and  44  is for illustrative purposes, since they are not required in the invention. 
     In FIG. 4, a clutched drive lock is illustrated for keeping friction rollers  64  and  66  in engagement with the peripheries of wheels  20  and  22 . It consists of a handle  81  and a detent lever  82  that are affixed to a common axle  85  which is pivotally mounted to U section of frame  12 . Detent lever  82  carries a roller  83  at its end. When a user rotates handle  81 , roller  83  forces tubular bearing member  62  to move rearward, forcing friction roller  64  and  66  into engagement with wheels  20  and  22 . A locked condition is maintained when roller  83  drops into a depression  84  in tubular bearing member  62 . In the locked condition, a user can sustain hands free motorized propulsion while traveling long and straight distances. The arrangement may be spring loaded so that the operation of the handles to brake either or both of the wheels will release roller  83  form depression  84 , to disengage the clutched drive lock mechanism. 
     The forwardly extending frame leg  18  is not found in conventional wheelchairs and could pose an impediment to users with disable legs. In FIG. 5, an intermediate padded platform  88  is shown mounted to frame leg  18 . The padded platform  88  softens the impact when dismounting and provides an intermediate step to assist in climbing up onto the chair. While not shown, it should be apparent that a speed control of the power chair may be desired and may be readily accomplished by the providing a throttle control that is operable by the user. 
     What has been described is a novel power chair that is light enough in weight to be hand propelled and readily transportable. It is recognized that numerous changes to the described embodiment of the invention will be apparent to those skilled in the art without departing from its true spirit and scope. Ale invention is to be limited only as defined in the claims.