DESC:BACKGROUND
Technical Field
[0001] The embodiments herein generally relate to electric wheelchairs, and more particularly, an affordable electric wheelchair assembly that increases the stability and maneuverability while riding even in undulated terrain surfaces.
Description of the Related Art
[0002] Wheelchairs and similar conveyances remain a critical part to allowing mobility for individuals with injuries or medical conditions that otherwise prevent them from walking or make walking more difficult. While many standard wheelchair designs that have small front wheels (e.g. castor wheels) to perform adequately on even surfaces, they are not suited for usage on uneven surfaces. There are more sophisticated wheelchairs that are adapted for rough terrain, however these are highly expensive, require high maintenance costs and not easy to store and transport. Further, spare parts for most standard wheelchairs are not readily available in local areas, which restrict mobility of the individuals with injuries or disabilities for a certain period of time till they are serviced or repaired. Existing wheelchairs also do not provide portability and volume reduction, which enables the wheelchairs to be stored in a vehicle, for example.
[0003] Accordingly, there remains a need for an affordable electric wheelchair assembly that is suited for maneuvering even in undulated terrain surfaces.
SUMMARY
[0004] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0005] In an aspect, an electric wheelchair assembly is disclosed. The electric wheelchair assembly includes a first front driving wheel, a second front driving wheel, a first hub, a second hub, a first motor, a second motor, and a control unit. The first front driving wheel is attached to a left side of the electric wheelchair assembly and the second front driving wheel is attached to a right side of the electric wheelchair assembly. The first hub is adapted to integrate the first front driving wheel with a first chain ring and the second hub is adapted to integrate the second front driving wheel with a second chain ring. The first chain ring and the second chain ring houses a first bearing and a second bearing, where the first bearing is fitted with a first axle, and the second bearing is fitted with a second axle. The first motor is adapted to operate the first front driving wheel and a second motor is adapted to operate the second front driving wheel in an alternate rotation. The first motor is coupled with the first front driving wheel using a first chain drive to provide an independent rotation to the first front driving wheel and the second motor is coupled with the second front driving wheel using a second chain drive to provide the independent rotation to the second front driving wheel. The control unit includes a joystick, microcontroller, and one or more power MOSFETs. The joystick is adapted to obtain an input from the user and transmit a signal to a microcontroller. The microcontroller is adapted to transmit a control signal to one or more power MOSFETs based on the signal received from the joystick. The one or more power MOSFETs is adapted to operate the electric wheelchair assembly corresponding to the control signal received from the microcontroller.
[0006] The electric wheelchair assembly is constructed using the bicycle components that are readily available to enhance the affordability of the electric wheelchair assembly. The electric wheelchair assembly includes foldable components to provide volume reduction in order to store it in a vehicle. The electric wheelchair assembly is adapted to manoeuver effectively even in undulated terrains.
[0007] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:
[0009] FIG. 1 illustrates an isometric view of an electric wheelchair assembly according to an embodiment herein;
[0010] FIG. 2 illustrates a top view of the electric wheelchair assembly according to an embodiment herein;
[0011] FIG. 3 illustrates a side view of the electric wheelchair assembly according to an embodiment herein;
[0012] FIG. 4 illustrates a front view of the electric wheelchair assembly according to an embodiment herein;
[0013] FIG. 5 illustrates an exploded view of a control unit of the electric wheelchair assembly according to an embodiment herein;
[0014] FIGS. 6A-6B illustrate exploded views of a rear castor wheel of the electric wheelchair assembly according to an embodiment herein;
[0015] FIG. 6C illustrates a cross sectional view of the rear castor wheel of the electric wheelchair assembly according to an embodiment herein; and
[0016] FIG. 7 illustrates a method for manoeuvering the electric wheelchair assembly according to an embodiment herein.

DETAILED DESCRIPTION OF THE DRAWINGS
[0017] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0018] There is a need for an improved electric wheelchair design that maintains effective stability while riding even in undulated terrain surfaces that further remains affordable and easy to maintain. The embodiments herein achieve this by providing an electric wheelchair assembly that is constructed using bicycle components which are readily available. Referring now to the drawings, and more particularly to FIGS. 1 through 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0019] FIG. 1 illustrates an isometric view of an electric wheelchair assembly according to an embodiment herein. The electric wheelchair assembly includes a first front driving wheel 102A, a second front driving wheel 102B, a rear castor wheel 104, a first chain drive, a second chain drive, a first hub 106A, a second hub 106B, a frame 108, a first motor 110A, a second motor 110B, a first customized axle, a second customized axle, a battery 112, a first bearing 116A (not shown in FIG. 1), a second bearing 116B and a control unit. The first front driving wheel 102A is attached to a left side of the electric wheelchair assembly and the second front driving wheel 102B is attached to a right side of the electric wheelchair assembly. In one embodiment, the one or more front driving wheels are attached to a front end of the electric wheelchair assembly. The first front driving wheel 102A is coupled to the first motor 110A using the first chain drive to provide an independent rotation to the first front driving wheel 102A. The second front driving wheel 102B is coupled to the second motor 110B using the second chain drive to provide the independent rotation to the second front driving wheel 102B. The first chain drive includes a first chain 118A (not shown in FIG. 1) and a first chain ring 120A. The second chain drive includes a second chain 118B and a second chain ring 120B. The first motor 110A and the second motor 110B operate the first front driving wheel 102A and the second front driving wheel 102B respectively in both forward rotation and reverse rotation independently.
[0020] In one embodiment, the first front driving wheel 102A and the second front driving wheel 102B are operated in an alternate rotation (i.e. opposite direction) using the first motor 110A and the second motor 110B respectively to achieve zero turn radius. The first motor 110A includes a first small gear that is adapted to couple the first motor 110A to the first chain ring 120A. The second motor 110B includes a second small gear that is adapted to couple the second motor 110B to the second chain ring 120B. In one embodiment, the first chain ring 120A and the second chain ring 120B are larger in size (i.e. includes more number of teeth) compared to the first small gear and the second small gear respectively to obtain optimal torque by means of gear reduction. The first motor 110A and the second motor 110B are positioned using one or more base plates to keep lengths of the first chain 118A and the second chain 118B in equal. The arrangement of the first motor 110A and the second motor 110B using the one or more base plates reduces dragging in the first front driving wheel 102A and the second front driving wheel 102B respectively. The one or more base plates include one or more adjustable mechanical slits or grooves that are used to provide ideal tolerances to the first motor 110A and the second motor 110B and the first chain drive and the second chain drive. The first front driving wheel 102A and the second front driving wheel 102B are large in size compared to the size of the rear castor wheel 104.
[0021] The large size (i.e. an optimized tyre size) of the first front driving wheel 102A and the second front driving wheel 102B and the gear reduction facilitates the electric wheelchair assembly to operate with stability and ease while travelling even in undulated terrain surfaces. In one embodiment, the first motor 110A and the second motor 110B are permanent magnet DC motors (PMDC) with a gear reduction. The rear castor wheel 104 is attached to a rear end of the electric wheelchair assembly. The zero turn radius is achieved by providing the alternate rotation in the first front driving wheel 102A and the second front driving wheel 102B. The zero turn radius is further achieved by the rear castor wheel 104 in turning the electric wheelchair assembly.
[0022] The frame 108 includes a foldable swing arm 114, a removable backrest 122, a first foldable armrest 124A, a second foldable armrest 124B, a first foldable footrest 126A and a second foldable footrest 126B. The first foldable armrest 124A and the second foldable armrest 124B are adapted to fold from an initial armrest position to a folded armrest position. The foldable footrest 126A and the second foldable footrest 126B are adapted to fold from an initial footrest position to a folded footrest position to provide volume reduction when folding the electric wheelchair assembly. In one embodiment, the battery 112 is a valve-regulated lead acid (VRLA) battery. The battery 112 may be any type of battery that is suitable and/or adapted to operate with the electric wheelchair assembly. The electric wheelchair assembly further includes a suspension mechanism 128, seat plate and an ergonomic seat.
[0023] The suspension mechanism 128 is adapted to operate the electric wheelchair assembly with comfort when travelling in the undulated terrain surfaces. The suspension mechanism 128 may be quickly released from an initial position so that the foldable swing arm 114 along with the rear castor wheel 104 rotates around and gets folded under the space of the battery 112 to provide volume reduction. The volume reduction may provide portability to store the electric wheelchair assembly in a vehicle while transporting. The first hub 106A and the second hub 106B are used to integrate the first front driving wheel 102A and the second front driving wheel 102B with the first chain ring 120A and the second chain ring 120B respectively. The first chain ring 120A and the second chain ring 120B house the first bearing 116A and the second bearing 116B respectively. The first customized axle and the second customized axle may be a snug fit in the first bearing 116A and the second bearing 116B respectively. The control unit controls the electric wheelchair assembly based on inputs received from a user.
[0024] FIG. 2 illustrates a top view of the electric wheelchair assembly according to an embodiment herein. The electric wheelchair assembly includes the first front driving wheel 102A, the second front driving wheel 102B, the rear castor wheel 104, the first chain drive, the second chain drive, the frame 108, the first motor 110A, the second motor 110B, the foldable swing arm 114, the removable backrest 122, the first foldable armrest 124A, the second foldable armrest 124B, the first foldable footrest 126A, the second foldable footrest 126B and the suspension mechanism 128. The function of these components as has been described above.
[0025] FIG. 3 illustrates a side view of the electric wheelchair assembly according to an embodiment herein. The electric wheelchair assembly includes the second front driving wheel 102B, the rear castor wheel 104, the second chain drive, the frame 108, the second motor 110B, the first customized axle, the second customized axle, the foldable swing arm 114, the second chain 118B, the second chain ring 120B, the removable backrest 122, the second foldable armrest 124B, the second foldable footrest 126B and the suspension mechanism 128. The first customized axle includes the first hub 106A with a first standard axle. The second customized axle includes the second hub 106B axle with a second standard axle. The function of the other components as has been described above.
[0026] FIG. 4 illustrates a front view of the electric wheelchair assembly according to an embodiment herein. The electric wheelchair assembly includes the first front driving wheel 102A, the second front driving wheel 102B, the rear castor wheel 104, the first chain drive, the second chain drive, the frame 108, the first motor 110A, the second motor 110B, the battery 112, the foldable swing arm 114, the removable backrest 122, the first foldable armrest 124A, the second foldable armrest 124B, the first foldable footrest 126A and the second foldable footrest 126B. The function of these components as has been described above.
[0027] FIG. 5 illustrates an exploded view of the control unit 504 of the electric wheelchair assembly according to an embodiment herein. The control unit 504 includes a joystick 506, a microcontroller 508 and one or more power MOSFETs 510A-N. The joystick 506 (i) obtains input from the user 502 and (ii) transmits a signal to the microcontroller 508. In one embodiment, the joystick 506 is an IP54 rated joystick. The IP54 rated joystick is both dust resistant and splash resistant. The joystick 506 is operated by the user 502. The joystick 506 may be any type of joystick that is suitable and/or adapted to operate with the electric wheelchair assembly. The microcontroller 508 transmits a control signal to the one or more power MOSFETs 510A-N based on the signal received from the joystick 506. The one or more power MOSFETs 510A-N operates the electric wheelchair assembly corresponding to the control signal received from the microcontroller 508. The one or more power MOSFETs 510A-N are further used to deliver power to the first motor 110A from the battery 112 and the second motor 110B in a controlled manner.
[0028] The electric wheelchair assembly further includes an accelerometer and a gyroscope that assists the control unit 504 to achieve a hill hold assist and a traction control. The hill hold assist and the traction control are obtained by applying reverse power to the first motor 110A and the second motor 110B in opposite to the direction of a slope to keep the electric wheelchair assembly in stationary position. In one embodiment, the hill hold assist and the traction control restricts the electric wheelchair assembly from sloping under gravitational force and provides sufficient time to the user 502 to operate (e.g. turn) the electric wheelchair assembly in the desired direction.
[0029] FIGS. 6A-6B illustrate exploded views of the rear castor wheel 104 of the electric wheelchair assembly according to an embodiment herein. The rear castor wheel 104 is adapted to operate the electric wheelchair assembly in a front or a back direction by applying a force which is supplied by the first motor 110A and the second motor 110B in either of the first front driving wheel 102A or the second front driving wheel 102B. The rear castor wheel 104 is characterized by a castor biasing assembly 602 comprises a stem, a bearing set, a fork assembly 604 and a spring plunger 612. The stem is coupled with a groove. A hole 608 emended on the stem and the spring plunger 612 is inserted into the hole 608.
[0030] The bearing set is placed on a sleeve and tightened. The castor biasing assembly 602 is placed on a stock. The string plunger 612 is tightened so that required lock force is achieved. In an embodiment the castor biasing assembly is used in any application requiring castor biasing such as hospital beds, and push trolleys. The castor biasing assembly helps the wheelchair to go in a straight line, without the castor biasing assembly it would be a difficult take control of the wheelchair in day to day use.
[0031] FIG. 6C illustrates a cross sectional view of the rear castor wheel 104 of the electric wheelchair assembly according to an embodiment herein. The the rear castor wheel 104 is characterized by a castor biasing assembly 602 comprises a stem, a bearing set, a fork assembly 604 and a spring plunger 612.
[0032] FIG. 7 illustrates a method for manoeuvring the electric wheelchair assembly according to an embodiment herein. At step 702, attaching a first front driving wheel 102A. to a left side of the electric wheelchair assembly and a second front driving wheel 102B is attached to a right side of the electric wheelchair assembly. At step 704, integrating a first hub 106A of the first front driving wheel 102A with a first chain ring 120A and a second hub 106B of the second front driving wheel 102B with a second chain ring 120B. The first chain ring 120A and the second chain ring 120B houses a first bearing 116A and a second bearing 116B, where the first bearing 116A is fitted with a first axle, and the second bearing 116B is fitted with a second axle. At step 706, operating is adapted to the first front driving wheel 102A using a first motor 110A and the second front driving wheel 102B using a second motor 110B in an alternate rotation. At step 708, coupling the first motor 110A with the first front driving wheel 102A using a first chain drive to provide an independent rotation to the first front driving wheel 102A and the second motor 110B with the second front driving wheel 102B using a second chain drive to provide the independent rotation to the second front driving wheel 102B. At step 710, controlling the electric wheelchair assembly based on inputs received from a user using a control unit 502. The control unit 502 includes a joystick 506, a microcontroller 508, and one or more power MOSFETs 510A-N. The joystick 506 is adapted to obtain an input from the user 502 and transmit a signal to the microcontroller 508. The microcontroller 508 is adapted to transmit a control signal to one or more power MOSFETs 510A-N based on the signal received from the joystick 506, The one or more power MOSFETs 510A-N is adapted to operate the electric wheelchair assembly corresponding to the control signal received from the microcontroller 508.
[0033] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims. ,CLAIMS:I/We claim:
1. An electric wheelchair assembly comprising:
a first front driving wheel (102A) and a second front driving wheel (102B), wherein the first front driving wheel (102A) is attached to a left side of the electric wheelchair assembly and the second front driving wheel (102B) is attached to a right side of the electric wheelchair assembly;
a first hub (106A) and a second hub (106B), wherein the first hub (106A) is adapted to integrate the first front driving wheel (102A) with a first chain ring (120A) and the second hub (106B) is adapted to integrate the second front driving wheel (102B) with a second chain ring (120B),
wherein the first chain ring (120A) and the second chain ring (120B) houses a first bearing (116A) and a second bearing (116B), where the first bearing (116A) is fitted with a first axle, and the second bearing (116B) is fitted with a second axle;
a first motor (110A) is adapted to operate the first front driving wheel (102A) and a second motor (110B) is adapted to operate the second front driving wheel (102B) in an alternate rotation,
wherein the first motor (110A) is coupled with the first front driving wheel (102A) using a first chain drive to provide an independent rotation to the first front driving wheel (102A) and the second motor (110B) is coupled with the second front driving wheel (102B) using a second chain drive to provide the independent rotation to the second front driving wheel (102B); and
a control unit (504) is adapted to control the electric wheelchair assembly based on inputs received from a user, wherein the control unit (504) comprising:
a joystick (506) is adapted to obtain an input from the user (502) and transmit a signal to a microcontroller (508),
wherein the microcontroller (508) is adapted to transmit a control signal to one or more power MOSFETs (510A-N) based on the signal received from the joystick (506), wherein the one or more power MOSFETs (510A-N) is adapted to operate the electric wheelchair assembly corresponding to the control signal received from the microcontroller (508).

2. The electric wheelchair assembly as claimed in claim 1, comprising a frame (108), wherein the frame (108) is coupled with foldable swing arm (114), a removable backrest (122), a first foldable armrest (124A), a second foldable armrest (124B), a first foldable footrest (126A) and a second foldable footrest (126B).

3. The electric wheelchair assembly as claimed in claim 1, comprising a rear castor wheel (104), wherein the rear castor wheel (104) is adapted to operate the electric wheelchair assembly to move freely in a right or a left direction, wherein for the electric wheelchair assembly to move in a front or a back direction a force is applied which is supplied by the first motor (110A) and the second motor (110B) in either of the first front driving wheel (102A) or the second front driving wheel (102B).

4. The electric wheelchair assembly as claimed in claim 3, wherein the rear castor wheel (104) is characterized by a castor biasing assembly that comprises a stem, a bearing set, a fork assembly and a spring plunger, wherein the stem is coupled with a groove.

5. The electric wheelchair assembly as claimed in claim 3, comprises a hole emended on the stem, wherein the spring plunger is inserted into the hole in order to lock the rear castor wheel (104) from moving freely in the front or the back direction.

6. The electric wheelchair assembly as claimed in claim 3, wherein the bearing set is placed on a sleeve and tightened, wherein the spring plunger is tightened at the hole to achieve a required lock state in order to over come fluttering and fishtailing of the electric wheelchair.

7. The electric wheelchair assembly as claimed in claim 1, comprising a battery (112), wherein the battery (112) is adapted to operate the electric wheelchair assembly.

8. The electric wheelchair assembly as claimed in claim 1, comprising a suspension mechanism (128), wherein the suspension mechanism (128) is adapted to be released from an initial position so that the foldable swing arm (114) is below the battery (112) and the rear castor wheel (104) is in front of the battery (112).

9. The electric wheelchair assembly as claimed in claim 1, wherein the first chain drive comprises a first chain and the first chain ring (120A) and the second chain drive includes a second chain (118B) and the second chain ring (120B).

10. The electric wheelchair assembly as claimed in claim 1, wherein the one or more power MOSFETs (510A-N) are used to deliver power to the first motor (110A) and the second motor (110B) from the battery (112) in a controlled manner.