Patent Description:
The present application generally relates to a removable power assist for a manual wheelchair, and more particularly relates to a device for converting or retrofitting a manual wheelchair into an electric wheelchair.

In <NUM>, an estimated <NUM> million Americans used a wheelchair on a regular basis; up from <NUM> million in <NUM>. Based off the <NUM> Census, <NUM>,<NUM>,<NUM> Americans are disabled and receiving income-based assistance. Of that group, <NUM>% report ambulatory difficulty. There is also a population that needs a wheelchair temporarily e.g. <NUM>-<NUM> months and would prefer not to incur the expense of an electronic wheelchair even though it is preferred over a manual wheelchair.

Electronic wheelchairs and many of the innovations in the field are very expensive; and there is a significant price gap between the most expensive manual wheelchair and the cheapest electronic wheelchair, which often ranges in the thousands of dollars. Other limitations of electric wheelchairs, in addition to cost, include: portability (foldable); weight; and structural bulk. There are devices on the market for converting manual wheelchairs to electronic wheelchairs but they are flawed so that they cannot be installed by an end user sitting in the chair, are heavy, not portable, have poor surface contact for the propulsion system and/or cannot be disengaged without uninstalling the device from the chair.

What is needed is a device for converting a manual wheelchair into a power driven system in a cost effective, portable, easy to install and use, lightweight, alternately convertible from electric to manual without uninstalling the device. The device should be adaptable to existing manual wheelchairs without the need of professional installation.

<CIT> discloses mobility device for converting a manually powered wheelchair or stationary chair to a powered mobile chair. The mobility device includes a housing, a pair of independently and/or simultaneously operable reversible motors, and a pair of drive members. The drive members may be in the form of frictional contact members for driving the rear wheels of a wheelchair or drive wheels for supporting and driving a stationary chair. A control device can be provided to control operation of the drive motors, and thus, movement of the stationary or wheelchair. The mobility device may include one or more rechargeable batteries which may be supported internally or externally of the housing.

<CIT> discloses a detachable electric wheelchair module, which includes a module frame detachable from the backrest frame of a manual wheelchair to replace expensive electric wheelchairs and improve mobility for disabled people. A rechargeable battery is installed on the module frame with two motors driven by the battery; and the device can be separated from the wheels and used as a general manual wheelchair.

<CIT> discloses a driving unit that is freely attachable and detachable to a front wheel and a rear wheel in a dead space under the seat of a wheelchair. The centre of the unit is positioned to be lower than a rear wheel by mounting it to a lower-side pipe frame. The motor unit is supported by only a supporting shaft of a bracket and is freely swingable with respect to a base frame.

<CIT> relates generally to motorized wheelchairs for invalids, and more particularly to an improved driving unit which can be easily mounted on and removed from such chairs.

According to the invention, there is provided a foldable wheelchair according to appended claim <NUM>.

According to the invention, there is provided a method for converting a foldable manual wheelchair to a foldable electronic wheelchair according to appended claim <NUM>.

In accordance with teachings of the present invention a device for converting a manual wheelchair into an electronic wheelchair is provided. Herein described is a manual wheelchair accessory device configured to attach to a manual wheelchair that will convert the manual wheelchair to an electric wheelchair, while still retaining the advantages that manual wheelchairs provide. The device includes an attachable power source affixed to a standard manual wheelchair.

The present invention provides a device having a joystick, a communication unit, two motors, two retractable friction rollers two engagement units and one or two power source(s). The joystick is operably connected to a communication unit. The communication unit is operably connected two motors. Each motor includes an axle connected to a rotor. A retractable friction roller is mounted on the axle. The roller is placed in contact with a wheel of a manual wheelchair. The engagement unit is attached to the manual wheelchair to detachably attach the friction roller to the wheel. The power source is operably connected to the motor and the joystick.

The present invention provides a second motor that is operably connected to the communication unit and the power source. The communication unit is operably connected to the joystick. The second motor includes a second axle connected to a second rotor. This embodiment includes a second friction roller that is mounted on the second axle. The second roller is placed in contact with a second wheel of the manual wheelchair to facilitate powered motion. In another embodiment, the joystick may be operably connected to the rotors and is operably programmable to generate commands for the motors.

The present invention easily converts a manual wheelchair to a powered, smart wheelchair. Features of the present invention include <NUM>) using the friction roller's contact to the wheel to generate directed force; <NUM>) the ability to engage and disengage the friction roller to the wheels of the wheelchair which allows the user to propel the wheelchair with manual propulsion while the device is disengaged but still attached to the wheelchair - a feature essential if the battery or motor cease to function; <NUM>) the ability to fold the wheelchair with device attached to it without altering the folding of or normal space occupied by a standard manual wheelchair; <NUM>) unit portability. In one embodiment, the device includes a safety guard to prevent a user's fingers from becoming caught in the motor or the gears. In another embodiment, the motors are bi-directional and independent of one another so that the motor attached to each wheelchair wheel can turn the opposite direction and rotate the wheelchair in place. Using the present invention, both acute and long-term care wheelchair companies and individual users can affordably bring their equipment and standard of care to a higher, professional level.

<FIG> illustrates a block diagram of the device <NUM> in accordance with one embodiment of the present invention. In this embodiment, the device <NUM> includes a joystick <NUM>, at least one retractable friction roller <NUM>, along with associated engagement unit <NUM> and a power source <NUM>. The joystick <NUM> is operably connected to a communication unit <NUM>. The joystick <NUM> is explained in detail in conjunction with <FIG> and <FIG> of the present invention.

The communication unit <NUM> is operably connected to a motor <NUM>. The communication unit <NUM> is explained in detail in conjunction with <FIG> of the present invention. The motor <NUM> includes an axle <NUM> and a rotor <NUM>. The motor <NUM> is explained in detail in conjunction with <FIG> of the present invention. The axle <NUM> is shown and explained in detail in conjunction with <FIG> of the present invention.

The retractable friction roller <NUM> is mounted on the axle <NUM>. During operation of the device <NUM>, the retractable friction roller <NUM> is put in contact with at least one wheel <NUM> (show in <FIG>) of a manual wheelchair <NUM> (shown in <FIG>). The retractable friction roller <NUM> is explained in detail in conjunction with <FIG> and <FIG> of the invention.

The engagement unit <NUM> is attached to the wheelchair <NUM> (shown in <FIG>) to detachably attach the retractable friction roller <NUM> and the wheel (shown in <FIG>). The engagement unit <NUM> is explained in detail in conjunction with <FIG>, <FIG> and <FIG> of the present invention. The power source <NUM> is operably connected to the motor <NUM> and the joystick <NUM>. The power source <NUM> is shown and explained in detail in conjunction with <FIG> of the present invention. The device <NUM> converts the manual wheelchair <NUM> into an automatic wheelchair.

<FIG> illustrates a side view of one embodiment of device <NUM> attached to a manual wheelchair <NUM>. The joystick <NUM> allows the user to control the direction and speed of the motor <NUM> (shown in <FIG>). In an embodiment, the joystick <NUM> is attached to an arm <NUM> of the manual wheelchair <NUM>.

In one embodiment, a user is able to control the direction, movement and speed of the device <NUM> using the joystick <NUM>. More specifically, the movement and speed of the wheel <NUM> of the wheelchair <NUM> is controlled by an end-user using the joystick <NUM> and the communication unit <NUM> (shown in <FIG>).

In one embodiment, the joystick <NUM> is programmable and enabled to store instructions for controlling the speed and direction of motor <NUM> (shown in <FIG>). The joystick <NUM> receives power from the power source <NUM> (shown in <FIG>). The use of a battery operated joystick is known for controlling power wheelchairs.

In one embodiment, the power source <NUM> is a battery. The batteries may be rechargeable such as but not limited to using an ordinary 110V or 220V charger. Sample batteries that may work with this device include but are not limited to a primary battery (non-chargeable) and secondary batteries such as Lithium-ion (Li-ion), Nickel Cadmium (Ni-Cd), Nickel-Metal Hydride (Ni-MH) and Lead-Acid.

<FIG> illustrates a top perspective view of the device <NUM> attached to the manual wheelchair <NUM> in accordance with an embodiment of the present invention. In this configuration, the retractable friction roller <NUM> is mounted on the axle <NUM> (shown in <FIG>) and rotated by activation of the motor <NUM>.

In one embodiment, the device includes a brushless hub motor with a friction surface. Types of motors that may be used include but are not limited to a geared hub motor, a brushed hub motor, a brushless geared hub motor, a brushed geared hub motor, a brushed geared hub motor, or any other similar motor. Hub motors are very common in power wheelchairs but are typically used for separate wheels that contact the ground directly. Friction surfaces may include but are not limited to high friction surface treatments, high friction polymers and high friction detailing applied to the surface that contacts the wheelchair wheel.

In the present invention, the retractable friction roller <NUM> is placed in contact with at least one wheel <NUM> of the manual wheelchair <NUM> to rotate the wheel <NUM> and move the wheelchair <NUM>. The retractable friction roller <NUM> rotates the wheel <NUM> by friction force. This is a unique feature of the present invention. Other devices are commonly based on motor to ground movements, PAW uses a friction roller to the wheel to generate movement.

In one embodiment, the retractable friction roller <NUM> is shaped to have a centerless concave rim housing configured to provide high friction surface facing the wheel <NUM> of the wheelchair <NUM>. The centerless concave rim housing acts as a wheel hub to yield a high percentage of surface contact. In one embodiment, the high friction surface of the retractable friction roller <NUM> faces the wheelchair wheel <NUM> and is customizable to fit the curve and or size of the wheel <NUM>.

In an embodiment, the material of high friction surface of the retractable friction roller <NUM> is rubber or polyurethane. However, it would be readily apparent to those skilled in the art that various types of material such as silicone, foam, sand paper, grit tape, sponge-rubber foam etc. may be envisioned without deviating from the scope of the present invention. In another embodiment, the wheels <NUM> of wheelchair <NUM> are made using a high friction surface, and the roller <NUM> is made of steel, aluminum or other similar hardened, textured surface.

The motor <NUM> is configured to rotate the retractable friction roller <NUM>. The retractable friction roller <NUM> is mounted on the axle <NUM> (shown in <FIG>) and the rotor <NUM> (shown in <FIG>) rotates the first axle resulting in rotation of the retractable friction roller <NUM>. In an embodiment, the motor <NUM> is a brushless DC motor with a friction surface. However, it would be readily apparent to those skilled in the art that various types of motor such as geared hub motor, brushed hub motor, brushed geared hub motor etc. may be envisioned without deviating from the scope of the present invention.

In another embodiment, the device <NUM> further includes a second motor <NUM> operably connected to the communication unit <NUM> and the power source <NUM> (shown in <FIG>). The communication unit <NUM> splits into another communication unit <NUM> that operably connects to the second motor <NUM>. The communication unit <NUM> and the another communication unit <NUM> are both operably connected to the joystick <NUM>. In another embodiment, the joystick <NUM> further include control buttons <NUM> operably connected to the motor. The control buttons <NUM> controls speed of the motor <NUM> (shown in <FIG>).

In an embodiment, the communication unit <NUM> and the another communication unit <NUM> is a single wired (not shown) communication unit operably connected to the joystick <NUM>. Examples of the communication unit <NUM> and the another communication unit <NUM> include but not limited to cables, wires, Bluetooth, NFC. It would be readily apparent to those skilled in the art that various types of communication unit such as wired or wireless unit may be envisioned without deviating from the scope of the present invention.

The second motor <NUM> includes a second axle (not shown) connected to a second rotor (not shown). The device <NUM> further includes a second friction roller <NUM> mounted on the second axle (not shown). The second roller <NUM> is placed in contact with a second wheel <NUM> of the manual wheelchair <NUM>. Alternatively, the second roller <NUM> is mounted to the axle <NUM> and the motor <NUM> provides motor torque to rotate the second friction roller <NUM> and the friction roller <NUM> (not shown).

Similarly, to the retractable friction roller <NUM>, the second retractable friction roller <NUM> includes a centerless concave rim housing configured to provide high friction surface facing the second wheel <NUM> of the wheelchair <NUM>. The principle and function of the second motor <NUM> and second friction roller <NUM> is the same as the motor <NUM> and retractable friction roller <NUM> as previously described.

The device <NUM> further includes a second engagement unit <NUM> attached to the manual wheelchair <NUM> to detachably attach the second friction roller <NUM> and the second wheel <NUM> of the wheelchair <NUM>. The engagement unit <NUM> detachably attaches the friction roller <NUM> and the wheel <NUM>. The engagement unit <NUM> and the second engagement unit <NUM> is attached behind seating area <NUM> of wheelchair <NUM> and top of the wheel <NUM> and the second wheel <NUM> respectively.

<FIG> illustrates perspective view of engagement unit <NUM> in accordance with another embodiment of the present invention. The engagement unit <NUM> includes a lever <NUM> operably connected to a lever mechanism unit <NUM>, a turnbuckle <NUM> connected to the lever mechanism unit <NUM> and an attachment unit <NUM> operably connected to the turnbuckle <NUM>. The attachment unit <NUM> comprises clamps (shown in <FIG>) and a spring loaded unit (shown in <FIG>).

In one embodiment of the device, the retractable friction roller (<NUM>, shown in <FIG>) is operably connected to the turnbuckle <NUM>. The lever <NUM> is actuated by the user and results in engaging and disengaging of the retractable friction roller (<NUM>, shown in <FIG>) from the wheel <NUM>. Thus the lever <NUM> results in converting a manual wheelchair into a powered wheelchair and vice versa.

With reference to <FIG>, in an embodiment of the present invention, the power source <NUM> is a battery. The batteries are chargeable using an ordinary 110V or 220V charger. Examples of battery include but not limited to primary battery (rechargeable) and secondary batteries (non-rechargeable), including but not limited to batteries such as Lithium-ion(Li-ion), Nickel Cadmium(Ni-Cd), Nickel-Metal Hydride(Ni-MH), and Lead-Acid.

<FIG> illustrates perspective view of the device <NUM> in accordance with another embodiment of the present invention. The attachment clamps <NUM> and a spring loaded unit <NUM> engage and disengage the retractable friction roller <NUM> and the wheel <NUM>.

With reference to <FIG>, the friction roller <NUM> is mounted on the axle <NUM>. In an embodiment of the present invention, the friction roller <NUM> has an opening to receive the axle <NUM>. The axle <NUM> is a cylindrical elongated rod to pass through the opening to rotate the friction roller <NUM> on receiving motor torque from the rotor (<NUM>, shown in <FIG>).

Examples of the attachment unit <NUM> include simple mechanical devices such as but not limited to a curved-head bolt, bolt, carriage bolt, T-bolt, T head bolt, round head bolt, barrel bolt, hex-head bolt, spring, screw clamp, mechanical coupling, latch, rod clamp, rail clamp, light, round center mount, mount bracket, pole clamp, pipe clamp, quick release clamp, rack clamp mount, or handlebar clamp mount on the backrest frame of wheelchair <NUM> and provides contact between the friction roller <NUM> and the wheelchair wheel <NUM> respectively.

The total weight for the entire device <NUM> is approximately <NUM>,<NUM> (<NUM> pounds). It is expected that the speed is <NUM>-<NUM>,<NUM> kmph (<NUM>-<NUM> MPH) adjustable, maximum carrying capacity of around <NUM>,<NUM> (<NUM> pounds), with a maximum incline of around <NUM> degrees.

It would be readily apparent to those skilled in the art that second retractable friction roller; second engagement unit; and second motor performs exactly same functions as described in the description for retractable friction roller; engagement unit; and motor respectively.

In other embodiments one of ordinary skill in the art will be able and may make changes to the size and materials of the friction roller; the size and type of motor or battery used; and/or the type of controller or joystick; and the size and type of attachment devices used to fix the device to the manual wheelchair such as but not limited to a screw clamp. In one embodiment a casing for each of the two units may be added for safety, convenient travel and appearance. In another embodiment, the device may be used as a power assist to any object that is traditionally transported on wheels via manual propulsion, such as baggage carts.

Claim 1:
A foldable wheelchair (<NUM>) comprising:
a first wheel (<NUM>) and a second wheel (<NUM>);
a seating area; and
a device (<NUM>) attached to the wheelchair (<NUM>) to convert the wheelchair (<NUM>) from a foldable manual wheelchair (<NUM>) to a foldable electronic wheelchair (<NUM>), the device (<NUM>) comprising:
a joystick (<NUM>) operably connected to a communication unit (<NUM>), the communication unit (<NUM>) operably connected to a first motor (<NUM>), the first motor (<NUM>) comprising a first axle (<NUM>) connected to a first rotor (<NUM>);
a first retractable friction roller (<NUM>) mounted on the first axle (<NUM>);
a first engagement unit (<NUM>) attached to the foldable wheelchair (<NUM>) behind the seating area and top of the first wheel (<NUM>) of the foldable wheelchair to detachably attach the first retractable friction roller (<NUM>) to the first wheel (<NUM>) behind the seating area of the foldable wheelchair (<NUM>) to generate directed force by contact between the first retractable friction roller (<NUM>) and the first wheel (<NUM>);
a power source (<NUM>) operably connected to the first motor (<NUM>) and the joystick (<NUM>);
a second motor (<NUM>) operably connected to the communication unit (<NUM>) and the power source (<NUM>), the second motor (<NUM>) comprising a second axle connected to a second rotor;
a second retractable friction roller (<NUM>) mounted on the second axle; and
a second engagement unit (<NUM>) attached to the foldable wheelchair (<NUM>) behind the seating area and top of the second wheel (<NUM>) of the foldable wheelchair (<NUM>) to detachably attach the second retractable friction roller (<NUM>) to the second wheel (<NUM>) behind the seating area of the foldable wheelchair (<NUM>) to generate directed force by contact between the second retractable friction roller (<NUM>) and the second wheel (<NUM>),
characterised in that
the second engagement unit (<NUM>) comprises:
a second lever operably connected to a second lever mechanism unit, the second lever mechanism unit being operably connected to a second turnbuckle, the second turnbuckle being operably connected to a second attachment unit,
and in that the first attachment unit (<NUM>) comprises:
a first spring loaded unit (<NUM>) operably connected to the first retractable friction roller (<NUM>); and
a first clamp (<NUM>) operably connected to the first spring loaded unit (<NUM>).