Abstract:
A power assist apparatus for powering a manual wheelchair may include one or more wheels, one or more motors that drives the one or more wheels, a remote operable to control the one or more motors, and a connector operable to attach to the manual wheelchair. The power assist apparatus may be quickly and easily attached to, and removed from a manual wheelchair.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of priority to U.S. provisional patent application titled “POWER-ASSIST FOR MANUAL WHEELCHAIR USERS”, application No. 61/308,329 filed Feb. 26, 2010, and incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to motorized devices, and more specifically relates to a device that may be attached to a manual wheelchair to assist in powering the manual wheelchair. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, a power assist apparatus for powering a manual wheelchair comprises one or more wheels, one or more motors that drives the one or more wheels, a remote operable to control the one or more motors, and a connector operable to attach to the manual wheelchair. 
     In another aspect of the present invention, a method for powering a manual wheelchair comprises attaching a power assist device to the manual wheelchair, using a remote control to control movement direction and speed of the power assist device, and driving one or more wheels on the power assist device in response to commands from the remote control. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a manual wheelchair power assist device in accordance with an embodiment of the present invention in use with a wheelchair; 
         FIG. 2  shows a plan view of the manual wheelchair power assist device of  FIG. 1 ; 
         FIG. 3  shows a side elevation view of the manual wheelchair power assist device of  FIG. 1 ; and 
         FIG. 4  shows a view of the schematics of the manual wheelchair power assist device of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
     Various inventive features are described below that can each be used independently of one another or in combination with other features. 
     Broadly, embodiments of the present invention generally provide a power assist for manual wheelchairs. A power assist device may be easily attached to a manual wheelchair so that the power assist device may pull the attached manual wheelchair. The power assist device may provide a remote, such as a joystick, that may allow the user of the wheelchair to easily control the power assist device, thereby controlling movement direction and speed of the device. 
     With reference to  FIGS. 1-4 , a power assist device  10  may connect to and power a manual wheelchair  32 . The power assist device  10  may connect to the manual wheelchair  32  via a foot support plate holder  24  on the device  10  that may accept and connect to a manual wheelchair foot support plate  34  on the manual wheelchair  32 . In one exemplary embodiment, the foot support plate holder  24  may be a plate having an indented shape that may accept the manual wheelchair foot support plate  34  into the indentation of the foot support plate holder  24 . Alternatively, the foot support plate holder  24  may have one or more raised edges that may help prevent the manual wheelchair foot support plate  34  from becoming disconnected from the foot support plate holder  24  during usage of the power assist device  10 . 
     The body power assist device  10  may be formed by a frame  28  that may be covered by a cover  30 . The power assist device  10  may have a caster  26  mounted under and on the end of the frame  28  that may be used for steering the device  10  and a pair of drive wheels  14  that may be driven by a pair of drive motors  12  that may also be attached to the frame  28 . The caster  26  plus the pair of drive wheels  14  may make the device in essence a three-wheel design. The caster  26  may also allow the device  10  to have nearly a zero turning radium. In alternative embodiments, the device  10  may have one or more drive wheels  12  and casters  26 . 
     A pair of batteries  18  situated within the power assist device  10  may power the drive motors  12 . In alternate embodiments, one or more batteries  18  may be used to power the drive motors  12 . A control unit  16  may connect to and control the motors  12 . A remote mounting bar  22  may be bolted to the wheelchair foot support table  34  and may be attached to a remote  20 . The remote mounting bar  22  may be bolted to the device  10  via a swivel that may allow the remote mounting bar  22  to be rotatable side to side, up and down, and/or in and out. The remote  20  may communicate with the control unit  16  to control the drive motors  12  thereby controlling movement of the device  10 . In an exemplary embodiment, the remote  20  may be a joystick, or the remote  20  may be any device suitable for use by the wheelchair user to control the movement, such as the direction and the speed, of the device  10 . 
     In use, the user of the wheelchair  32  may cause the wheelchair  32  to tilt back and roll forward so that the wheelchair foot support plate  34  is securely inserted into the foot support plate holder  24 . A pair of rods may also attach to the front of the wheelchair  32  via straps to further secure the wheelchair  32  to the device  10 . The user then may swing the remote mounting bar  22  in place up and down, in and out, or side to side, and may turn on the power to the device  10  using the remote  20 . The user may place one hand on the remote mounting bar  22  and use the other hand to control the remote  20 . 
     For example, the user may move a control knob on the remote  20  to go forwards, backwards, or to make a turn. The remote  20  may cause battery power from the pair of batteries  18  to be sent to the appropriate motor or motors in the pair of drive motors  12  to drive the drive wheels  14  so that the device  10  performs as directed by the remote  20 . 
     When the user is finished, the user may use the remote  20  to turn the device  10  off. The user may swing the remote mounting bar  22  out of the way, and then may cause the wheelchair  32  to tilt back and roll backwards to detach the device  10  from the wheelchair  32 . 
     Additionally, lights  36 , such as 12-volt LED lights, which may be controlled by a light switch  38 , may be added to the front and the back of device  10  to improve the visibility of the wheelchair user at night. A battery cut-off switch  40  may be used to keep the batteries  18  from running down when the device  10  is not in use, or the battery cut-off switch  40  may be used for theft protection purposes. A charging port  42  may allow the batteries  18  to be recharged. 
     The frame  28  may include two 1-inch square tubing each bent into an arc about 28-inches long. Two 6-inch pieces may be welded between the two 1-inch square tubing and a 16-inch tubing may be welded to the rear of the back tubing. A ⅛-inch sheet metal may also be welded to the bottom of the frame  28 . 
     The foot support plate holder  24  may be a pair of 16″ by 12″ by 1″ high density polyethylene (HDPE) plates stacked on top of one another, where the top plate has an empty interior area to form a cavity that may accept and hold the manual wheelchair foot support plate  34  of the wheelchair  32 . The foot support plate holder  24  may be connected to the frame  28  such as via a solid shank bolt about 2.5 inches long and ¾ inch in diameter. 
     The pair of drive wheels  14  may be two 3-inch by 12-inch wheels and the caster  26  may be a 3-inch wide wheel. The pair of drive motors  12  may be bolted onto motor supports on the frame  28  and may be two 24-volt motors having a 90-degree gearbox about 4-inches in diameter and 13-inches long. The batteries  18  may be placed at the bottom of the frame  28  between the pair of drive motors  12  and may be two 12-volt, —26-amp hours direct current batteries. 
     The remote mounting bar  22  may be a ½-inch pipe about three feet long, and may be bent in an L shape. 
     To make the wheelchair power assist device  10 , square tubing may be bent, cut, and welded to form the frame  28 . A steel plate may also be welded to the frame  28 . Motor mounts for mounting the drive motors  12  may be cut and welded to the frame  28 . The foot support plate holder  24  may be cut and secured to the frame  28  via a solid shank bolt. The caster  26  may be bolted to the bottom end of the frame  28 . The drive motors  12  may be bolted in a near-vertical position to the motor mounts on the frame  28  and the drive wheels  14  may be connected to the drive motors  12 . The batteries  18  may be installed into the frame  28  between the drive motors  12  and may be connected to the drive motors  12 . The control unit  16  may be connected to the drive motors  12 . The control unit  16  may also be wired to the remote  20 . The remote mounting bar  22  may be cut and bent into the appropriate shape and may be mounted via a swivel to the foot support plate holder  24 . The remote  20  may be attached to the remote mounting bar  22 . 
     It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.