This application is a powered folding chair incorporating a friction driving and braking system described and claimed in U.S. Pat. No. 6,371,228 issued Apr. 16, 2002 and U.S. Pat. No. 6,273,212 issued Aug. 14, 2001, the contents of which are incorporated by reference herein in their entirety.
This invention relates generally to vehicles and specifically to a folding motorized chair with mechanical traction control that folds flat and is light enough for a person to lift into the trunk of a car.
Contemporary power chairs may be divided into two categories: those that steer by selectively operated traction wheels and those that steer by turning the front wheel or wheels.
The traction-steered vehicles are commonly referred to as power wheelchairs. They have front casters and are controlled by a single joystick that interacts with a very complicated electronic control system for switching and modulating the requisite high current, low voltage, battery power. Power wheelchairs employ two gear motors to independently and directly drive the left and right traction wheels. These motors in various combinations of power input; propel, steer and brake the vehicle. It should be noted that, due to the requisite high ratio gearing of the vehicle, it is impossible to overdrive the motors (to allow the vehicle to coast) when traveling downhill. This inability to coast reduces its range of travel, particularly in graded or hilly areas. The two gear motors require large and heavy batteries to provide an acceptable range of travel. The excessive weight of power wheelchairs makes it humanly impossible to lift them off the ground so a van equipped with a mechanical lift or a loading ramp is needed to transport them. A further drawback of power wheelchairs is high cost, not only of the vehicle but of the specially equipped van as well.
Power chairs that directly steer a wheel (or a pair of wheels) are commonly referred to as scooters. Most scooters employ a tricycle configuration with steering of the front wheel being accomplished by means of a handlebar. This configuration results in far too large a turning radius for indoor maneuvering. Even in a large indoor area the front upright steering column precludes indoor activities like sitting at a desk or table. Scooters employ a single gear motor that drives the rear wheels through a differential. The differential is subject to traction loss due to split coefficient. This may occur for example, when either drive wheel loses traction on a wet or slippery surface resulting in neither drive wheel being able to provide a driving force. The result is that the vehicle user, who is often incapable of walking or significant unassisted movement; is literally stranded.
Because of their front wheel steering and tricycle configuration, scooters are highly unstable at practically all speeds. A sudden turn of the handlebar will cause the tricycle to tip. The centrifugal force acting on such a high center of gravity vehicle tends to throw the vehicle (and occupant) up onto the front wheel and the outside drive wheel. If the occupant does not immediately steer out of the turn (which is sometimes impossible) a rollover will occur.
The gear motor, differential drive and frame structure needed to support a front handlebar steering system makes the cost and weight only slightly reduced as compared to the joy stick controlled power wheelchairs discussed above. The size and weight of these vehicles is impossible to fit in the trunk of a car. A van equipped with a mechanical lift or loading ramp is needed to transport scooters. A further draw back of the scooters is cost. The sheer size and weight contribute to the cost not only of the scooter but the specially equipped van as well.
There are some scooters of relatively lighter weight but they are still too heavy to be manually lifted and too big to fit in a car trunk. These down-sized scooters have very poor performance and are limited to mild hills and smooth terrain. Some of these scooters can be taken apart by removing the upright steering column, the seat, and finally the battery pack. The components can be loaded into a car trunk piece by piece but assembly in a parking lot is inconvenient and dangerous. The battery pack is the heaviest part that in most cases weighs more than the weight of the present invention in its entirety, battery included.
Embodiments of the present invention provide a folding motorized chair that is light, compact, inexpensive and maneuverable. The folding motorized chair of embodiments of the invention will find ready application as a safe and stable vehicle by persons of all ages (provided that they have the use of both their arms). In its preferred embodiment as depicted in
Propulsion, steering, and braking of the inventive folding motorized chair is provided by selectively engaging the periphery of the rear traction wheels with corresponding motor-driven friction rollers or friction brake surfaces. Engagement between friction rollers or brake surfaces and the traction wheels is controlled by a pair of control levers that the user simply moves down for propulsion and up for braking. Normal turning is accomplished by engaging one friction roller with its corresponding fraction wheel. Very tight turns may be made by simultaneously engaging one friction roller with its associated traction wheel and engaging the opposite brake surface with its associated traction wheel. This configuration allows for the tight maneuvering necessary for indoor operation. When both control levers are held down, both friction rollers are engaged with their corresponding traction wheels. This acts like a solid axle delivering torque to each traction wheel directly, unlike the differential drive on the scooters mentioned above. A throttle control mounted at the grip of one of the control levers regulates an electronic speed control to vary the motors speed. While the preferred embodiment incorporates a DC motor, it should be understood that the invention is not to be so limited. A lightweight gasoline or propane engine may offer advantages for an off road sport version of the folding motorized chair.
There is a folding motorized assist chair implementation of the present invention that applies to users incapable of controlling the folding motorized chair themselves. A slight modification permits an assistant to take control with a set of controls handles mounted to the rear seat tubes. These handles are mechanically linked to accomplish the same control inputs as the user operated control levers described above. It takes enormous effort to push a wheelchair through a grassy park, or up a hill, but the folding motorized assist chair does all the work to make these activities as easy for an assistant as walking.
The power wheelchairs and scooters described above weigh from 150 to 300 pounds. To save weight with special lightweight batteries and materials is a waste of money because by design these vehicles are far too heavy to be lifted manually. The folding motorized chair weighs 36 pounds owing to its unique design and lightweight components such as: lithium ion battery, aluminum tubing, plastic components, and a highly efficient traction drive system. The folding motorized chair includes an inventive folding mechanism, including frame members and all periphery components which are mechanically coordinated to fold down and lock in a self-contained flat package that fits in the trunk of a small car.
In one embodiment of the invention, a lightweight folding motorized chair with mechanical traction steering comprises a folding quadrilateral mainframe, a pair of traction wheels, a pair of caster wheels, a driving and braking system, and a left and a right control lever. The folding quadrilateral mainframe folds into a substantially flat grouping of frame members when in a fully folded configuration. The pair of traction wheels is mounted for free rotation near a rear of the folding quadrilateral mainframe. The pair of caster wheels is mounted near a front of the folding quadrilateral mainframe. The driving and braking system are frictionally engageable with one or both of the traction wheels. The left and a right control lever selectively move the driving system and the braking system into engagement with one or both of the traction wheels for fractionally propelling, braking and steering the folding motorized chair.
The folding quadrilateral mainframe may mechanically sequence peripheral components into a substantially flat configuration as the folding quadrilateral mainframe moves into the fully folded configuration. The left and the right control levers may be mechanically sequenced to fold into a substantially flat position relative to the folding quadrilateral mainframe when in the fully folded configuration.
The peripheral components may include a swinging foot platform suspended from the front of the folding quadrilateral mainframe. The swinging foot platform may be adapted to be pushed back by one or more feet of a user entering the chair. The folding mainframe may be mechanically linked to retract the swinging foot platform into a substantially flat position relative to the folding quadrilateral mainframe members when in the fully folded configuration.
The peripheral components may include the pair of caster wheels mounted to lower extensions of the front quadrilateral frame members. The extensions may provide a lever action to retract the set of caster wheels into a flat position relative to the folding quadrilateral mainframe members when in the fully folded configuration.
A set of control levers may be facing rearward for use by an assistant walking behind the folding motorized chair. The set of control levers may be mechanically sequenced to fold into a substantially flat position relative to the folding quadrilateral mainframe when in the fully folded configuration.
The driving and braking system may comprise a motor and one or more friction rollers. The motor may deliver a passive braking effect when the motor is not electrified and the friction rollers are forced into engagement with the peripheral surface of the traction wheels.
In another embodiment of the invention, a foot platform system is suspended at a front of a personal mobility chair. The foot platform system is adapted to be pushed back by one or more body parts of a user as the user enters the chair.
In another embodiment of the invention, a personal mobility chair comprises a frame, two or more wheels rotatably affixed to the frame, a seat supported by the frame, and at least one foot platform suspended from at least one support arm pivotably affixed to the frame such that the foot platform is adapted to selectively pivot from a first position upward and backward to a second position when a force is applied to the at least one foot platform and to selectively pivot from the second position downward and forward to the first position when the force is removed.
The at least one foot platform may comprise one foot platform. The at least one support arm may comprise two support arms. The two support arms may be affixed to the foot platform at opposing ends of the foot platform.
The at least one foot platform may comprise first and second independent foot platforms. The at least one support arm may comprises first and second support arms. The first foot platform may be suspended from the first support arm. The second foot platform may be suspended from the second support arm. The first and second foot platforms may be each independently pivotable between the first position and the second position. The first and second support arms may be pivotably affixed to opposing sides of the frame.
The personal mobility chair may further comprise first and second stop pins. The first stop pin is affixed to a first side of the frame and configured to support the first foot platform in a third position. The second stop pin is affixed to a second side of the frame opposite the first side and configured to support the second foot platform in a fourth position different than the third position, such that first and second foot platforms do not contact each other when the first and second sides of the frame are moved toward each other.
A principal object of the invention is to provide a novel ultra-light folding motorized chair, which is light enough and small enough to be manually lifted and placed in the trunk of a small car.
Another object of the invention is to provide a novel folding motorized chair with tight turning capability for indoor use.
Another object of the invention is to provide a novel folding motorized chair reliable and inexpensive.
A still further object of the invention is to provide a motorized assist chair for users incapable of controlling the folding motorized chair themselves.
These and other objects and advantages of the invention will be apparent upon reading the following description in conjunction with the drawings in which:
Components and structure of the left and right side of the folding motorized chair are identical and for this reason only the right side will be described in detail. Referring to the drawings generally and to
An axle tube 14 is welded in place at the rear of frame member 10c. The axle tube 14 extends beyond the right and left frame members 10c to establish the wheelbase for the folding motorized chair. A shoulder bushing (not shown) is pressed into the ends of axle tube 14 to reduce the inner diameter (I.D.) to match the diameter of the wheel axle 15 which extends beyond the axle tube 14 to support a left and right pair of freewheeling traction wheels 16 & 17.
Referring to
An anti-tip wheel 85 is mounted to a bracket 86 that is welded to the underside of frame member 10c. The anti-tip wheel 85 is situated behind the wheel axle 15 and is spaced to never touch ground except in the event of a wheelie. When climbing steep hills a wheelie may occur but the anti-tip wheel 85 stops the chair from flipping over backwards. Note that a skilled user can still steer the traction steered folding motorized chair while riding a wheelie up the hill.
The propulsion and breaking control systems for the left and right traction wheels are identical and for this reason only the control system for the right traction wheel 16 will be described in detail. This propulsion and braking system is chosen for ultra-light weight, highly efficient use of energy and it is the only system known to be compatible with the folding mechanics described herein. As best seen in
Referring to
When the folding motorized chair is unoccupied the weight of the motor 31 forces the friction rollers 34 into engagement with the peripheral surface of the traction wheels 16 & 17. The ratio between peripheral surface of the traction wheels 16 & 17 and the small diameter friction roller is so high that the permanent magnet motor delivers braking effect that is ideal for this application. The motor's magnetic resistance holds the folding motorized chair in place while at rest but yields to a person pushing. The motor 31 delivers almost no braking effect once the chair is pushed at a stable speed but as soon as the pushing force stops the motor 31 delivers a magnetic breaking effect that slows the chair down to a full stop. This passive braking effect keeps the folding motorized chair from coasting off when the user inadvertently releases it on a hill. This passive braking effect precludes the need of a manual parking brake.
The throttle 30 controls speed from very slow up to a speed of roughly 6 miles per hour (MPH). A throttle limiter is anticipated to keep the speed at a very slow speed during the learning curve. This gives a user reflex time to learn the technique of controlling a new type of vehicle. Once confidence is achieved the throttle limiter can be removed. A switch mounted by the throttle grip for selecting between turtle for indoor use and rabbit for outdoor use is also anticipated, thereby providing two different speeds at any given throttle position depending on the position of the switch.
Most manual and power wheelchairs have left & right foot platforms which fold independently. They must be lifted up for entering the chair and deliberately pushed back down once seated and finally lifted back up to exit the chair. Referring to
The swinging foot platform 42, shown in
Referring again to
The arrangement shown in
What has been described is a novel lightweight folding motorized chair that is highly maneuverable. 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. The invention is to be limited only as defined in the claims.