GB2408245A

GB2408245A - Off road personal mobility vehicle

Info

Publication number: GB2408245A
Application number: GB0326869A
Authority: GB
Inventors: Christopher Nicholas Swift
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-11-19
Filing date: 2003-11-19
Publication date: 2005-05-25
Also published as: GB0326869D0

Abstract

An off road mobility device includes a folding frame 4 and a seat and has drive wheels 8, 10 mounted to the rear of the frame 6 independently rotatable and operable to drive the device. The suspension systems mounting the rear wheels to the frame are independent of one another and include a means to damp the vertical movement of the rear wheels. Two front wheels 1 steer the device and are mounted to the front of the frame via suspension systems 2 allowing the front wheels a degree of independent damped vertical movement and are free to rotate about an axis lying in their plane of rotation. The wheelbase width and length of the mobility device can be varied manually. The seat is mounted to the frame so that the seat can move between a first position (Figure 5) to maximise stability when operating and a second position (Figure 6) maximising access for ingress and egress of the user.

Description

OFF ROAD MOBILITY DEVICE

BACKGROUND OF THE INVENTION

The present invention relates to a four wheeled electrically powered offroad mobility device and among other features it comprises mechanisms to provide four wheel independent suspension, means for variable wheelbase width and length, seat which can be raised and moved forward to simplify ingress and egress, minimal frame incorporating means of folding and locking, and optional housing locations for battery units. Among other uses the invention is suitable for all kinds of outdoor recreational mobility and in addition for example for use by the less mobile whether through youth or old age and the physically less firm or physically disabled individuals.

There has been some development in the field of wheeled assistive off road mobility devices that are designed for particular sporting or leisure activities, some of which have limited ability off road. For instance, there are wheelchairs whose functionality is modified by incorporating hand cranked or electrically powered attachments for racing and which wheelchair mobility. Others in the art have proposed addition of oversized wheels for use on sand, grass, mud, and like terrain. All rely either on the user or gravity for motive power or on one or more able bodied assistants and many require the user to have considerable strength and balance thus limiting their use by the physically less able.

Electrically powered wheelchairs and pavement vehicles have been found to have limited off road mobility in terms of obstacle crossing, stability and their ability to cross soft surfaces. However, they are generally large and bulky and require extra equipment in the form of vehicle lifts or trailers to transport them.

SUMMARY OF THE INVENTION

The present invention is directed to an electrically powered off road mobility device for outdoor recreational use and incorporating a supportive seating arrangement low in the frame to maximise stability whilst providing a mechanism for it to rise, providing a level platform which allows the user for example to perform a sliding transfer, along with mechanisms to vary the track width of the device and to allow the device to easily be dismantled and carried in a family size car.

The powered seat mechanism allows the user weight to be placed low in the device to maximise stability and incorporates the means to move forwards to provide a level surface above the ground, clear of hindrance to the rear wheels. This improves access for ingress and egress.

The rear suspension is typically of the trailing arm type with suspension means provided by for example but not limited to torsion or compact spring and damper units. The rear wheel is held by a swing arm which pivots along the axis of the rear frame cross member. The torsion arrangement spring and damping properties of the suspension are provided by inserts of a resilient material packed around the square shaft connecting the swing arm to the frame along its pivot axis. As the swing arm moves it compresses the packing material therefore providing the suspension properties.

The front suspension incorporates individual units for each front wheel, each consisting of a parallel linkage with the pivot axis along the length of the mobility device. Spring and damper units are fitted to provide the suspension characteristics.

The rear electric motors are built into the rear wheel hubs and incorporate an external disc brake. Differential action of the wheels when fuming is achieved by the free wheeling mechanism built into each wheel hub.

The width of the mobility device can be varied manually by removing retaining fittings from either side of the front axle and either side of the rear cross member.

Extending shafts can then be moved out or in to vary track width. Once adjustment is complete the retaining fittings can be replaced. In a similar manner the central rail of the frame can be extended or retracted to elongate or reduce the device wheelbase length.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the present invention will be better understood by those of ordinary skill in the art and others upon reading the ensuing specification, when taken in conjunction with the appended drawings, wherein: FIGURE. 1 is a view of the right hand side of the off road mobility device with the seat and handlebars in the driving position, made in accordance with the principles of the present invention; FIGURE. 2 is an isometric view of the frame assembly of the off road mobility device of FIGURE. 1 with the seat and handlebars in the raised position; FIGURE. 3 is a front view of the off road mobility device with the seat and handlebars in the driving position, made in accordance with the principles of the present invention; FIGURE. 4 is a rear view of the off road mobility device with the seat and handlebars in the driving position, made in accordance with the principles of the present invention; FIGURE. 5 is a view of a portion of one embodiment of the off road mobility device of the present invention showing a side view of the seat in a lowered position showing one embodiment of the seat raising mechanism; FIGURE. 6 is a view of a portion of one embodiment of the off road mobility device of the present invention showing a side view of the seat in a raised position showing one embodiment of the seat raising mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

One embodiment of an off road mobility device made in accordance with the principles of the present invention is shown in Figures. 1, 2, 3 and 4. A principle frame consisting of a central frame member 4 and the front 25 and rear 6 cross members is mounted longitudinally the centre of the device. The front end of the central member 4 is secured to the middle of the front cross member 25 and the rear end secured to the middle of the rear cross member 6. An alternate embodiment of the frame incorporates a device to allow a degree of limited rotational movement along the central frame member 4 and is mounted between it and the front cross member 25.

Two sleeve extensions 28 are inserted into the end of the front cross member 25 and releasably attach to prevent them moving either rotating or in and out along their axes.

Secured to the ends of these extensions are head tubes 19 mounted so as to provide correct caster angle for Ackerman steering. These head tubes 19 house and secure appropriate bearings to allow the steering rods 29 connected to the independent suspension units 2 to turn freely. The front wheels 1 are mounted behind the centre axis of the steering rods 29 in accordance with Ackerman steering principles. The front wheels 1 are generally lightweight consisting of inner tube and tyre, rim and hub connected with spokes, for example bicycle wheels the spokes 3, 9 of which are illustrated in a stylised manner in Figures. 1 and 2. An alternate embodiment of the front wheels incorporates brake discs mounted on the vehicle side of the wheel hub and a means of applying a resistive force to the rotational movement of the disc, mounted to the independent suspension units 2.

Secured below the front cross member 25 is a foot rest 20,consisting of a step like structure and preferably incorporating padded strapping to hold the users feet position when negotiating rough ground. Additionally mounted along the front edge of the front cross member 25 a container constructed out of water resistant material for example plastic which is suitable for example for housing the batteries used to power device. The container is easily removable for ease of loading of the chair for transport. s

Two piece rear sleeve extensions 22 are inserted half-way into the end of the rear cross member 6 and the inner portion releasably attached to prevent them moving either rotating or in and out along their axes. The two sections of the sleeve are connected via a material or mechanism with spring and damping properties such as blocks pressed around a central connecting shaft. This material or mechanism will allow the outer half of the sleeve to have limited rotational movement along its axis and forms the rear suspension. The trailing swing arms are secured to the outer section of sleeve 22. The rear wheels 10 complete with hub motors 8 fitted to the far end of the swing arms, the rotational position of the sleeve 22 should be adjusted in the rear cross member 6, to give sufficient vertical clearance between the bottom of the rear cross member and the ground for example thirty centimetres. In this way the ride height ofthe off road mobility device can be adjusted.

The rear wheel motors X are preferably electric brushless hub motors incorporating a mechanism or control system to allow one rear wheel to turn faster than the other for example over run free wheel mechanism. The free wheel mechanism will accommodate the differential speeds on the rear wheels when negotiating tight turns.

The seat mechanism shown in Figure 5 is shown in right side prop le and is mirrored on the left side of the seat. The seat back 12 is connected to the seat base 24 via pivot points 33 on either side of the seat. This allows the seat back to rotate around an axis running across the width of the seat. At two adjustable positions along each side of the seat base 24 are secured clamps 32. These connect in a manner to allow rotation as shown in Figures. 5 and 6, in turn to radius arms mounted beneath the seat 34 and 35. These front 35 and rear 34 radius arms are connected to the rear cross member via brackets 5 secured to the same. As the seat moves in the manner shown in Iiigures. 5 and 6 the seat back is kept in an upright position by a link 30 from the cross member bracket 5 to an adjustable position on the seat back 12. One embodiment of the seat mechanism uses a DC electric linear actuator to raise and lower. Another embodiment uses a DC electric rotational actuator acting through either the front 35 or rear 34 radius arms.

Both the seat back 12 and seat base 24 are constructed with posts and rails respectively running along the sides. These posts and rails are held apart by cross members on the back 11 and seat base 21. An adjustable waterproof upholstery sling backrest and seat 23 is stretched between the posts and rails giving a degree of lateral support to the upper body as necessary.

Control of the vehicle is preferably by the handlebar arrangement shown where the users hands are comfortably secured into grips 14. These grips are mounted to downward hanging links 16 which are secured on either end, in a manner which will allow their rotational position to be adjusted, on cross shaft 26. This cross shaft 26 passers through support 27 that is located its midpoint. Support 27 houses appropriate bearings which will allow shaft 26 to rotate a pre determined angle each way from its resting position which occurs when the links 16 are straight down. The centre shaft support 27 is in turn secured to the control boom 18 via a securing system which will allow rotational movement about a vertical axis drawn through the support midpoint.

As the handlebar assembly is moved about this axis it will cause steering links 17 to move backwards and forwards thereby steering the vehicle. The exact nature of the link taking movement from the steering links 17 to cause the independent suspension units 2 to turn will depend upon the physical capability of the user. It should be understood by those of skill in the art that for individuals with good upper body strength, a mechanical linkage may suffice whereas for those with limited upper body strength, a power assisted system may be required. One embodiment of such a system would be to replace steering links 17 with variable displacement linear transducers.

Their movement could be used to proportionately control a DC electric linear actuator powering the steering linkage.

Preferably, the off road mobility device of the present invention will have appropriate linkages and wiring installed that permits the easy plugin of any of the aforementioned types of control units so that the chair can be easily fitted to the physical capabilities of the user.

The position of the control boom 18 can be variable through a pivoted securing mechanism with its axis along the front cross member 25, and should allow it to be fixed in either the driving position as in Figure 1 or in the ingress/egress position Figure 2.

It is clear from the above disclosure that an off road mobility device is described that includes independent trailing arm suspension for each of the two rear wheels together with front independent suspension units for the front two wheels. The track width of the device can be varied by altering the positions of extension sleeves in the Dont and rear frame cross members. The device also includes a seat that can be moved between two positions, depending on whether the seat is in the driving position or the ingress/egress position for a user. The handlebar arrangement can be embodied so that it does not require the user to have any hand function and limited upper body strength.

It should be understood by those of ordinary skill in the art and others that the embodiment of the invention illustrated and described herein is exemplary only and that changes can be made to the illustrated embodiment while remaining within the scope of the present invention. Therefore, the invention should be defined only by the scope of the claims appended hereto.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. An off road mobility device including: a frame; a front cross member secured on a front end of said frame; a rear cross member secured on the rear end of said frame; two independently moving sleeves mounted to said front cross member in such a way as to allow the total assembly width to be varied and secured in position, each sleeve incorporating a head tube mounted perpendicularly to one end of the sleeve at its centre; a left hand independent suspension unit mounted at the base of a steering tube rotatably mounted to the left head tube to rotate about its central axis; a right hand independent suspension unit mounted at the base of a steering tube rotatably mounted to the right head tube to rotate about its central axis; two front wheels each rotatably mounted on the input portion of the left and right hand independent suspension units to rotate about a first axis; first and second rear wheels rotatably mounted on a rear end of said frame to rotate about a second axis, each of said first and second rear wheels independently rotatable with respect to the other; first suspension means for mounting said first rear wheel to said frame to pivot about a pivot axis, said suspension means constructed and arranged to permit a predetermined mount of vertical movement of said first rear wheel relative to said frame; second suspension means for mounting said second rear wheel to said frame to pivot about a pivot axis, said second suspension means constructed and arranged to permit a predetermined amount of vertical movement of said second rear wheel relative to said frame; a seat mounted on said frame including a bottom portion, back portion support stays, a transverse flexible connection and a back portion, the bottom edge of the back portion and bottom portion of said seat being flexibly connected together and mounted so as this connection be positioned approximately on a plane defined by the pivot axis of said front wheels and the pivot axes of said first and second rear wheels thereby providing said off road mobility device with a low center of gravity; drive means drivingly connected to both said first and second rear wheels for propelling said off road mobility device; and a controller for controlling said drive means and for steering said off road mobility device.
2. The off road mobility device of claim 1, wherein said drive means includes: a drive motor drivingly connected within the hub of both said first and second rear wheels, incorporating mechanisms to allow each wheel to rotate at different speeds when turning the off road mobility device.
3. The off road mobility device of claim 1 and 2, wherein said first suspension system includes a damping means for damping the motion between said first rear drive wheel and said frame.
4. The off road mobility device of claim 1,2 and 3, wherein said second suspension system includes a damping means for damping the motion between said second rear drive wheel and said frame.
5. The off road mobility device of claim 1, 2, 3 and 4, wherein said first and second suspension systems include a trailing arms with a pivoting axis transverse to the length of said frame at its point of connection with said frame.
6. The off road mobility device of claim 1, 2, 3, 4 and 5, wherein said first and second damping means comprise torsion arrangement suspension are provided by inserts of a resilient material packed around a shaft connecting said trailing arms and said frame.
7. The off road mobility device of claim l, 2, 3, 4 and 5, wherein said first and second damping means comprise springs and shock absorbers mounted between said trailing arms and said frame.
8. The off road mobility device of claim 1, said seat being movable between a first position and second position; in which the f rst position has the flexible connection axis of the back and bottom portions of said seat lie approximately with the axes of rotation of the first and second rear wheels, and the bottom portion is slightly inclined rearwards, and the second position has the bottom portion of the seat horizontal and raised and moved forward from the axes of rotation of the first and second rear wheels.
9. The off road mobility device of claim 1 and 8, further including a seat lift means operable to move said seat between said first and second positions.
10. The off road mobility device of claim 1, 8 and 9, wherein said seat lift means comprises an electrical actuator connected between said seat and said frame.
11. The off road mobility device of claim 1, 8, 9 and 10, wherein said seat lift means comprises a parallel linkage mounted between the frame and the bottom portion of the seat.
12. The off road mobility device of claim 1, 8, 9, 10 and 11, wherein said seat back portion maintains its angle of incline relative to the elevation of a plane defined by the pivot axis of said front wheels and the pivot axes of said first and second rear wheels by means of a seat back support rotatably connected at either end between the seat back portion and said frame.
13. The off road mobility device of claim I, 8, 9, 10, 11 and 12 wherein a controller for controlling drive means and for steering the off road mobility device is connected to said drive motors and operable to energize each of said drive motors as required to propel said off road mobility device.
14. The off road mobility device of claim 1, 8, 9, 10, 11 and 13, wherein said controller comprises a joystick.
15. The off road mobility device of claim 13, wherein said controller comprises a handlebar arrangement operable to energize said first or second drive motors as required to propel said off road mobility device.
16. The off road mobility device of claim 15, wherein said handlebar arrangement comprises left and right hand grips connected in such a way forwards movement of handlebar arrangement operates a braking system, backwards movement of handlebar arrangement operates said drive motors and independent movement of left and right sides of handlebar arrangement steers said off road mobility device.
l 7. The off road mobility device of claim 1, wherein said a left hand and right hand independent suspension units include a spring and damper mounted between said front wheel and said steering tube.
18. The off road mobility device of claim l, wherein said front cross member includes a footrest for the user of said off road mobility device.
] 9. The off road mobility device of claim 1, wherein said frame includes a mechanism to fold said frame to reduce its overall length, which can be temporarily secured in the folded or unfolded positions.
20. The off road mobility device of claim 6, wherein said shaft incorporates a means to allow said trailing arms to be temporarily secured to said frame.
21. The off road mobility device of claim 1, wherein said two front wheels are each rotatably mounted on the input portion of the left and right hand independent suspension units in such a way as to allow them to be removed as required.
22. The off road mobility device of claim l, wherein said first and second suspension means incorporate a sleeve mounted to said rear cross member in such a way as to allow the total assembly width to be varied and temporarily secured in position, by which means the track width of the mobility device can be varied.