GB2446136A

GB2446136A - Auxiliary wheel structure for a wheelchair

Info

Publication number: GB2446136A
Application number: GB0701747A
Authority: GB
Inventors: Ming-Yi Huang
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-01-30
Filing date: 2007-01-30
Publication date: 2008-08-06
Also published as: GB0701747D0

Abstract

An auxiliary wheel structure 40 is disposed to a frame of an assistive mobility device such as a wheelchair or scooter and behind the front wheels 62 of the assistive mobility device, and includes a motor 41, a gear set, such as a worm gear 42, a pair of micro-switches 36,37 and an auxiliary wheel 38/60. The gear set is driven by the motor. The pair of micro-switches is disposed to an upper end and a lower end of the gear set respectively. The motor drives the gear set to control the height variation of the auxiliary wheel. When the gear set is moved up or down to touch the micro-switches, a signal is generated by the micro-switches to stop the running of the motor after the auxiliary wheel contacts the ground or is raised. The auxiliary wheel is lowered to raise the front wheels 62 off the ground so that the wheelchair can go over an obstruction 64, or to keep the seat horizontal when descending a hill.

Description

* 2446136

AUXILIARY WHEEL STRUCTURE

FIELD OF THE INVENTION

The present invention generally relates to an auxiliary wheel structure of an assistive mobility device, and more specifically relates to a technique that enables the assistive mobility device to be lifted up so as to keep in a horizontal status or move across an obstruction.

BACKGROUND OF THE INVENTION

As technology is developed gradually, the appearance of an assistive mobility device such as a wheelchair, a power wheelchair or a power scooter may help disabled people to act like normal people. However, referring to FIG. 1, when a wheelchair 10 is driven on a downhill, a seat 11 of the wheelchair 10 may not be kept in a horizontal status, and a disabled user (not shown) who sits on the wheelchair 10 may be scared. Another drawback is that when the wheelchair 10 faces an obstruction 13 as shown in FIG. 2, a front wheel 14 may not move across the obstruction 13 smoothly due to its small size.

To overcome the foregoing shortcomings, the inventor of the present invention based on years of experience in the related field to conduct extensive researches and experiments, and finally invented an auxiliary wheel structure for an assistive mobility device.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide an auxiliary wheel structure applied to an assistive mobility device. The auxiliary wheel structure supports the assistive mobility device to go over an obstruction or lift up a front wheel of the assistive mobility device on a downhill to maintain a horizontal status.

To achieve the foregoing object, the auxiliary wheel structure is disposed to a frame of the assistive mobility device and behind the front wheels of the assistive mobility device, and includes a motor, a gear set, a pair of micro-switches and an auxiliary wheel. The gear set is driven by the motor, and a side of the gear set includes a roller. The pair of micro-switches is disposed to an upper end and a lower end of the gear set respectively. The auxiliary wheel is pivoted under one of the micro-switches without contacting the ground. The roller rotates through the motor to drive the gear set to control the height variation of the auxiliary wheel. When the gear set is moved up or down to touch the micro-switches, a signal is generated by the micro-switches to stop the running of the motor after the auxiliary wheel grabs the ground or is raised.

The features of the auxiliary wheel structure include the following: a). The safety of a user who sits on the assistive mobility device can be ensured when the assistive mobility device is driven on a downhill.

b). The assistive mobility device can move across the obstruction smoothly.

To make it easier for our examiner to understand the object of the invention, its innovative features and performance, a detailed description and technical characteristics of the present invention are described together with the drawings as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a conventional assistive mobility device that is driven Onto a descent; FIG. 2 is a schematic diagram of a conventional assistive mobility device that faces an obstruction; FIG. 3 is a schematic diagram illustrates an auxiliary wheel structure for an assistive mobility device according to an embodiment of the invention; FIG. 4 is another schematic diagram illustrates an auxiliary wheel structure according to an embodiment of the invention; FIG. 5 is a schematic diagram of an auxiliary wheel structure of a wheelchair driven onto a descent; and FIG. 6 is a schematic diagram of an auxiliary wheel structure of a wheelchair driven to move across an obstruction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the related figures for the auxiliary wheel structure according to a preferred embodiment of the present invention, wherein the same elements are described by the same reference numerals.

Referring to FIG. 3 for the schematic diagram illustrates an auxiliary wheel structure according to an embodiment of the invention. The auxiliary wheel structure 30 supports an assistive mobility device 31 to go over an obstruction or lift up a front wheel 32 of the assistive mobility device 31 on a downhill to maintain a horizontal status. To simplify the illustration, the auxiliary wheel structure 30 shown in the embodiment only takes one auxiliary wheel structure although the assistive mobility device 31 must have two auxiliary wheel structures 30.

The auxiliary wheel structure 30 is disposed to a frame 33 of the assistive mobility device 3 I and behind the front wheel 32 of the assistive mobility device 3 1, and includes a motor 34, a gear set 35, a pair of micro-switches 36, 37 and an auxiliary wheel 38. The gear set 35 is driven by the motor 34, and a side of the gear set 35 includes a roller (not shown in the figure). The pair of micro-switches 36, 37 is disposed to an upper end and a lower end of the gear set 35 respectively. The auxiliary wheel 38 is pivoted under one of the micro-switches 36, 37 without contacting the ground. More specifically, the auxiliary wheel 38 is pivoted to two bend plates 70 disposed to the micro-switch 36. The roller rotates through the motor 34 to drive the gear set to control the height variation of the auxiliary wheel 38. When the gear set is moved up or down to touch the micro-switches 36, 37, a signal is generated by the micro-switches to stop the running of the motor 34 after the auxiliary wheel 38 grabs the ground or is raised.

1 5 The assistive mobility device is preferably a wheelchair, a power wheelchair or a power scooter. The motor is preferably an AC/DC (alternating currentldirect current) electric motor. The gear set is preferably a worm gear, and can be further covered up by a protection casing 39 to prevent the outside from damaging the mechanism of the gear set. The frame 33 is preferably made by a metal material or other materials.

Referring to FIG. 4 for a detail diagram illustrates an auxiliary wheel structure according to an embodiment of the invention. The auxiliary wheel structure 40 includes an electric motor 41, a worm gear 42, the pair of micro-switches 36, 37, the auxiliary wheel 38 and a brake 46. Furthermore, the electric motor 41 further has transmission shaft (not shown in the figure) to pivot the roller to drive the worm gear 42. The brake 46 is disposed to the electric motor 41 and preferably a magnetic brake. In addition, the assistive mobility device also has a control unit 43 electrically connected to the electric motor 41. The control unit 43 is preferably a controller composed of an integrated circuit. The assistive mobility device 40 further includes a power source 45 disposed to the control unit 43 and composed of a battery for supplying electric power to the control unit 43. The electric power is preferably 12/24 voltage DC (direct current).

The motion of the auxiliary wheel 38 is that the roller rotates through the transmission shaft of the electric motor 41 to drive the worm gear 42 to control the height variation of the auxiliary wheel 38, and when the worm gear 42 is moved up or down to touch the micro-switches 36, 37, a signal 44 is transmitted to the control unit 43 from the micro-switches 36, 37. The brake 46 then is commanded by the control unit 43 to disconnect the operation of the electric motor 41 after receiving the signal 44. In another word, a magnetic coil of the magnetic brake 46 would generate an opposite magnetic field to enable the transmission shaft of the electric motor 41 to generate a reverse action through the command of the control unit 43 so as to slow down the speed, thereby stopping the running of the electric motor 41 after the auxiliary wheel 40 grabs the ground or is raised. Herein the magnetic coil can be directly disposed to the transmission shaft.

The control unit 43 is further connected to an interface 47 composed of a power switch 471 and a control button set. The interface 47 is disposed on a handrail of the ass islive mobility device 3 1 (not shown in the figure). The control button set further includes an up button 472, a down button 473 and a pause button 474. When the down button 473 is pressed, the auxiliary wheel 38 is lowered and the assistive mobility device 31 is lifted from 0 to 45 degrees, and when the up button 472 is pressed, the auxiliary wheel 38 is controlled to return to an original position from the ground to be higher than the front wheel as shown in FIG. 3. Moreover, when the pause button 474 is pressed, the motion of the auxiliary wheel 38 can be temporarily stopped.

Referring to FIG. 5 for the schematic diagram of an auxiliary wheel structure of a wheelchair is driven onto a descent. An auxiliary wheel 50 disposed to a frame 5 1 of the wheelchair 52 and behind a front wheel 53 is lowered to contact the descent, and the wheelchair 52 is lifted to keep in a horizontal status. Herein the maximum of the lift angle 0 can be 45 degrees that corresponds to the descent. Therefore, the safety of a user (not shown) who sits on a seat 54 of the wheelchair 52 can be ensured.

Referring to FIG. 6 for a schematic diagram of an auxiliary wheel structure of a wheelchair is driven to move across an obstruction. An auxiliary wheel is lowered to contact the ground. The wheelchair 61 then is lifted up to help a front wheel 62 to move across the obstruction 64. After the front wheel 62 moves across the obstruction 64 smoothly, the auxiliary wheel 60 then is controlled to return to an original position so that the front wheel 62 can contact the ground.

While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.

Claims

What is claimed is: I. An auxiliary wheel structure applied to an assistive mobility device for going over an obstruction or lifting up a front wheel of the assistive mobility device on a downhill to maintain a horizontal status, the auxiliary wheel structure being disposed to a frame of the assistive mobility device and behind the front wheel of the assistive mobility device, the auxiliary wheel structure comprising: a motor; a gear set driven by the motor, and a side of the gear set having a roller; a pair of micro-switches disposed to an upper end and a lower end of the gear set respectively; and an auxiliary wheel pivoted under one of the micro-switches without contacting the ground, wherein the roller rotates through the motor to drive the gear set to control the height variation of the auxiliary wheel, and when the gear set is moved up or down to touch the micro-switch, a signal is generated by the micro-switch to stop the running of the motor after the auxiliary wheel grabs the ground or is raised.
2. The auxiliary wheel structure of claim 1, wherein the assistive mobility device is a wheelchair, a power wheelchair or a power scooter.
3. The auxiliary wheel structure of claim I, wherein the motor is an AC/DC (alternating currentidirect current) electric motor.
4. The auxiliary wheel structure of claim 1, wherein the gear set is a worm gear.
5. The auxiliary wheel structure of claim 1, wherein the gear set is further covered up by a protection casing.
6. The auxiliary wheel structure of claim 1, wherein the motor further has a transmission shaft to pivot the roller to drive the gear set.
7. The auxiliary wheel structure of claim 1, wherein the assistive mobility device further has a control unit electrically connected to the motor.
8. The auxiliary wheel structure of claim 7, wherein the control unit is a controller composed of an integrated circuit.
9. The auxiliary wheel structure of claim 7, wherein the control unit is further connected to an interface composed of a power switch and a control button set, and the interface is disposed on a handrail of the assistive mobility device.
10. The auxiliary wheel structure of claim 9, wherein the control button set further includes an up button, a down button and a pause button.
11. The auxiliary wheel structure of claim 10, wherein when the down button is pressed, the auxiliary wheel is lowered and the assistive mobility device is lifted up from 0 to 45 degrees, and when the up button is pressed, the auxiliary wheel is controlled to return to an original position from the ground to be higher than the front wheel.
12. The auxiliary wheel structure of claim 10, wherein when the pause button is pressed, the motion of the auxiliary wheel is temporarily stopped.
13. The auxiliary wheel structure of claim 1, wherein the assistive mobility device further includes a power source disposed to the control unit and composed of a battery for supplying electric power to the control unit.
14. The auxiliary wheel structure of claim 13, wherein electric power is 12/24 voltage DC.
15. The auxiliary wheel structure of claim 1, wherein the auxiliary wheel structure further includes a brake disposed to the motor, and the brake is a magnetic brake.
16. The auxiliary wheel structure of claim 15, wherein the brake is commanded by the control unit to disconnect the operation of the motor after the signal is further transmitted to the control unit.
17. The auxiliary wheel structure of claim 1, wherein the frame is made by a metal material or other materials.