WO2003020194A1

WO2003020194A1 - Improvements to mobility vehicles

Info

Publication number: WO2003020194A1
Application number: PCT/GB2002/003956
Authority: WO
Inventors: Fredrick Charles Brown
Original assignee: Fredrick Charles Brown
Priority date: 2001-08-31
Filing date: 2002-08-30
Publication date: 2003-03-13
Also published as: GB0121137D0

Abstract

There is provided a three-wheeled mobility vehicle (1) having a pair of rear wheels (2), a front wheel (3) and a seat (17). The vehicle further comprises at least two stabiliser wheels (14), with at least one stabiliser wheel (14) lying on each side of the front wheel (3); and a pair of footrests (22). One footrest (22) is positioned on either side of the front wheel (3) between the front wheel (3) and the corresponding stabiliser wheel (14), wherein each stabiliser wheel (14) has an axis of rotation that crosses substantially perpendicularly through a planar area bounded by the circumference of the front wheel (3).

Description

IMPROVEMENTS TO MOBILITY VEHICLES

The present invention relates to a mobility vehicle, and more particularly to improvements in electric mobility vehicles for the disabled.

People with mobility problems often require specialist transport to enable them access to places where a car or other motorised vehicle can not be driven, such as indoor areas and other restricted areas, for example supermarkets and shopping malls. Electric mobility vehicles have been designed for the disabled to give them this access, and may be used for travelling on public roads and paths.

There are two types of mobility scooters: three wheeled and four wheeled. However, there are a number of problems associated with both types of vehicles.

The three wheeled mobility vehicle provides maximum manoeuvrability for use in restricted areas, for example supermarkets and indoor use. But in certain situations such as traversing across a steep slope, turning too fast or hitting a large pot hole, the vehicle may lift a rear wheel making it unstable and the vehicle may tip over throwing the rider out.

The four wheeled vehicle is more stable, but requires a larger floor for feet placement because the front wheels intrude into the foot area. Consequently this either makes the vehicle longer in length, or the rider's leg angle more acute. Maximum manoeuvring is restricted because the front wheels do not have the steering lock angle of the three wheeled vehicle, i.e. the turning circle is larger for the four-wheel vehicle. For a mobility vehicle this is a big disadvantage.

Most mobility vehicle manufacturers endeavour to design the smallest sized product as this gives good manoeuvrability in tight spaces. In addition, a smaller product is more space efficient when dismantled for transport, for example in the boot of a car, and as a manufactured product it is cheaper to produce.

However, to achieve the smallest physical sized product most conventional mobility vehicles are designed so that the rider adopts the classic "sit up and beg" position when seated on the vehicle. This is the correct position for a person who is physically fit, but not for a person with mobility problems, particularly those suffering from muscle stiffness and stiff joints due to arthritis for example, heart attack victims, the elderly, amputees and those suffering involuntary leg spasms, amongst others. Primary considerations for such persons are the minimal bending of joints, limb security and comfort, as well as ease of manoeuvring with respect to four- wheeled vehicles and confidence in the vehicle with respect to three-wheeled vehicles.

The seat provided in most three-wheeled mobility vehicles is able to rotate so as to allow the rider to position themselves with ease onto the seat, and then rotate the seat back into the driving position, locked straight ahead. However, because the front wheel of a three-wheeled mobility vehicle protrudes into the area available for resting the rider's feet (feet placement area), it can be problematic for a person with mobility problems to position themselves into the driving position, where one leg is placed either side of the front wheel, when rotating the seat into the driving position.

The present invention seeks to address or significantly mitigate one or more of the aforementioned problems.

According to the present invention there is provided a three wheeled mobility vehicle having a pair of rear wheels, a front wheel and a seat, the vehicle comprising: at least two stabiliser wheels, with at least one stabiliser wheel lying on each side of the front wheel; and a pair of footrests, preferably positioned on either side of the front wheel between the front wheel and the corresponding stabiliser wheel, wherein each stabiliser wheel has an axis of rotation that crosses substantially perpendicularly through a planar area bounded by the circumference of the front wheel.

In a preferred embodiment the stabiliser wheels share a common axis of rotation that is parallel to and lies substantially below the axis of rotation of the front wheel with respect to the orientation of the vehicle in use. Preferably the stabilising wheels have a track width that is substantially comparable to that of the rear wheels i.e. preferably in the range of 70% to 100%, ideally about 90%, of the track width of the rear wheels. In a further embodiment the pair of footrests are pivotally connected to the frame of the vehicle, and are pivotally adjustable.

In another preferred embodiment the footrests are adjustable so that the distance of the footrests from the seat of the vehicle may be adjusted.

In another embodiment the pair of footrests are individually adjustable.

In a further embodiment the stabiliser wheels are castors that are revolvable in a plane parallel to the longitudinal motion of the vehicle straight ahead in use. Preferably the castors are fixed so that they do not revolve laterally with respect to the direction of motion of the vehicle.

In a further preferred embodiment the front wheel has a diameter substantially smaller than the diameter of the rear wheels. Preferably, the front wheel has a diameter substantially between 150mm and 170mm. Preferably still, the stabiliser wheel that is non-acting, in use during tipping, is operable to turn in towards the front wheel.

Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of the specific embodiments of the invention in conjunction with the accompanying figures.

Embodiments of the invention will now be described by way of example only, with reference to the drawings in which:

Figure 1 is a schematic diagram of the side view of a conventional mobility vehicle with a line drawing depicting the normal seated position of the rider;

Figure 2a is a schematic diagram of the front view of the conventional mobility vehicle of figure 1 ;

Figure 2b is a schematic diagram of the front view of the convential mobility vehicle of figure 1 shown in a leaning position to illustrate the amount of tilt the vehicle may undergo before the stabilising castors come into contact with the ground; Figure 3 is a schematic diagram of the side view of an embodiment of a mobility vehicle according the present invention, with a line drawing depicting the normal seated position of a rider;

Figure 4a is a schematic diagram of the front view of the embodiment of figure 3;

Figure 4b is a schematic diagram of the front view of the embodiment of figure 3, shown in a leaning position to illustrate the amount of tilt the vehicle may undergo before the stabilising wheels come into contact with the ground.

Figure 5 is a schematic diagram of the side view of a further embodiment of a mobility vehicle having a smaller-sized front wheel in accordance with the present invention, with a line drawing depicting the normal seated position of a rider;

Figure 6 is a schematic diagram of the front view of the front wheel as mounted in the front fork for the embodiment shown in Figure 5;

Figure 7 is a schematic diagram of a rubber shock mount;

Figure 8a is a schematic diagram of the plan view of the front wheel assembly for the embodiment of Figure 3 during normal use when the mobility vehicle is moving in a forwards direction;

Figure 8b is a schematic diagram of the plan view of the front wheel assembly for the embodiment of Figure 3, in use, when the mobility vehicle is experiencing tipping;

Figure 9a is a schematic diagram of the plan view of the front wheel assembly for the embodiment of Figure 5 during normal use when the mobility vehicle is moving in a forwards direction; and

Figure 9b is a schematic diagram of the plan view of the front wheel assembly for the embodiment of Figure 5, in use, when the mobility vehicle is experiencing tipping. A conventional three-wheeled mobility vehicle is shown in figures 1 , 2a and 2b, and a preferred embodiment of the proposed mobility vehicle is shown in figures 3, 4a and 4b.

With reference to figures 1 and 2a, the conventional mobility vehicle 1 has a pair of rear wheels 2 rotatable along a common axis, a front wheel 3 positioned ahead of the rear wheels 2 and lying midway along an axis parallel to that of the rear wheels 2, and a pair of stabilising castors 4 positioned along a common axis parallel to those for the front and rear wheels 3,2. The axis of rotation of the stabilising castors 4 lies behind the circumference of the front wheel 3, typically by some 200mm. The stabilising castors 4 are mounted under the forward floor pan 5 of the vehicle 1 , but lie within the track H of the rear wheels 2. The height of the castors 4 above ground level is typically about 70mm, and their purpose is to prevent the vehicle 1 from tipping over in extreme situations. However, this conventional arrangement is not very effective as the vehicle 1 is liable to a lean angle of around 15 degrees on a flat surface J before the stabilising castors 4 come in to use, as shown in figure 2b. The lean angle is all the more critical given the elevated sitting position of the rider and thus his high centre of gravity.

The length of the floor 6 of the vehicle 1 spans from a point below the front of the seat 7 to a point approaching the wheel arch 8 of the front wheel 3, thereby giving the rider a small area for feet placement and forcing a posture as depicted by the line drawing A in figure 1. In addition, this arrangement makes it difficult for the rider to place one leg either side of the front wheel 3 when rotating the seat 7 into the driving position. As can be seen from figure 1 the rider's leg angle at the knees as denoted by B, and the rider's body angle at the hips as denoted by C, are both fairly acute. The resulting body position is uncomfortable and impractical for many disabled riders.

A preferred embodiment of the invention will now be described, and is shown in figures 3, 4a and 4b, in which the components that are similar to those in the conventional mobility vehicle have the same numerals but are prefixed with the number 1. With reference to figures 3, 4a and 4b, the preferred embodiment comprises a pair of rear wheels 12 and a front wheel 13 arranged in a similar fashion to that of the conventional mobility vehicle 1. A noticeable difference however is that the wheelbase K of the conventional mobility vehicle 1 is longer than that of the preferred embodiment.

The preferred arrangement has a pair of stabilising wheels 14 that are restricted to revolving in a plane parallel to the longitudinal motion of the vehicle 11 straight ahead in use. Both stabilising wheels 14 lie along a common axis of rotation that is parallel to and below the axis of rotation of the front wheel 13. The stabilising wheels 14 are positioned either side of the front wheel 13 and have a track width L that is between 70% and 100%, preferably approximately 90%, of the track width of the rear wheels 12. The stabilising wheels 14 are typically between approximately 100mm to 160mm in diameter, but may be larger. They are preferably between about ¹/₃ and V_ the diameter of the front wheel which is preferably of a similar diameter to the rear wheels. Larger sized stabilising wheels are more effective at negotiating uneven terrain with minimal tilting of the vehicle 11.

The stabilising wheels 14 are connected to the front wheel 13 via a rod linkage system 40 that enables the stabilising wheels 14 to steer with the front wheel 13, as shown in Figures 8a and 8b.

The positioning of the axis of rotation of the stabilising wheels 14 in a plane N parallel to the axle 29 of the front wheel and extending vertically downwards, provides optimal stability for the vehicle in use. If the stabilising wheels were to be positioned so that their common axis of rotation lies rearwardly of the plane N, for example along the undercarriage 15 of the vehicle 11 or along the underside of floor areas 21 , the vehicle would be subject to a greater lean angle before the stabilising wheels 14 would be brought in to use. Clearance from the ground J is around 25mm for the stabilising wheels 14 which may be bolted to the vehicle frame. This lower clearance combined with the positioning and wide track of the stabilising wheels 14 gives the vehicle 11 greater stability than the conventional three-wheeled mobility vehicle 1, and is effective at preventing the vehicle 11 from tipping over in extreme conditions. The proposed arrangement gives rise to a lean angle of around 5° from the perpendicular on a flat surface J before the stabilising wheels 14 are brought in to use, as shown in figure 4b.

The axis of rotation of the stabilising wheels 14 crosses the front wheel 13 within the circumference of the front wheel 13, i.e. wherein each stabilising wheel 14 has an axis of rotation that crosses substantially perpendicularly through a planar area bounded by the circumference of the front wheel 13.

The floor 6 of the vehicle 11 spans from below the front of the seat 17 to an end point 5 in line with the axle 29 of the front wheel 13. End portions 21 of the floor areas extend from the wheel arch 18 of the front wheel 13 and dip downwards to the level of the stabilising wheels 14 at end points either side of the front wheel 13.

Individually adjustable footrests 22 are provided for feet placement on each side of the front wheel 13. One end of each footrest 22 is pivotally connected to the end point of the respective end portion 21 of the floor area through an axis of rotation running parallel to the axle 29 of the front wheel 13. The angle E of each footrest 22 to each end portion 21 of the floor areas is adjustable, as is the distance of the footrests 22 from the seat 17 of the vehicle 11 , i.e. the foot reach.

The foot reach for each footrest 22 may be adjusted to one of a number of predetermined positions using a locating lug found on the footrest 22 that fits into a slot on the vehicle frame corresponding to the desired foot reach position. The lug is fixed in place in the slot using a tightening screw. The footrests 22 may be pivotally connected to the end portions of the floor 21 using hinge mechanisms that allow the angle E of the footrest to the end portion to be varied within a pre-determined range, via the loosening and tightening of a screw. Other known mechanisms may be used for adjusting the footrests 22.

By bringing the feet placement area forward in the mobility vehicle, the body position of the rider is straightened when seated as indicated by the line drawing D in figure 3. This allows the seat 17 to be placed lower in the vehicle 11 by around 100mm. The effect of this is to bring the centre of gravity forwards and lower in the vehicle 11 , which allows the vehicle length, i.e. the wheelbase M, to be shortened by approximately 130mm and the track to be narrower by some 50mm. As mentioned earlier, the proposed arrangement straightens the body portion of the rider when seated on the vehicle 11. By bringing the rider's feet forward, the knee joints F are straightened as is the angle G of the hip joint of the rider. In this instance, depending on the seat height, the angle of the hip joint G may be improved by about 20° to 30° and the angle of the knee joint F may be improved by about 80°.

To prevent the rider from slipping down from the front of the seat 17, the adjustable footrests 22 may be fixed at the rider's desired position, and are individually adjustable. Foot strap restraints may be fitted to the footrests 22 to locate the lower limbs of the rider and prevent the lower limbs from slipping out of the footrests 22.

The stabilising wheels 14 used on the mobility vehicle 11 may be castors that are free-running in a forwards and a backwards direction with respect to the motion of the vehicle in use. Also, the stabilising wheels may be made of non-marking rubber tyres.

In another embodiment, as illustrated in Figure 5, the mobility vehicle 111 is similar to that shown in Figure 3 except the front wheel 113 has a smaller diameter than that of the front wheel 13, and a smaller diameter than that of the conventional mobility vehicle 1 shown in Figure 1. The use of the smaller front wheel 113 enables the feet placement area to be increased, and the obstruction area 30 to be decreased, thereby making it easier for the rider to place one leg either side of the front wheel 113 when rotating the seat 17 into the driving position. Also, the use of the smaller front wheel 113 enables the feet placement area to be increased without increasing the length X of the mobility vehicle 111.

Preferably the front wheel has a diameter of about 150mm to 170mm to allow greater room for manoeuvring in the feet placement area when mounting the vehicle. Since pneumatic tyres are not available in such small sizes, a solid tyre is used for the front wheel 113. The solid tyre used for the front wheel 113 may be composed of rubber. To prevent shock from being transferred from the solid tyre 113 through the handlebars to the rider, for example as a result of travelling over uneven terrain, potholes or kerbs, rubber shock mounts 32 are fitted either side of the tyre 113 as shown in Figure 6. As illustrated in Figure 7, each rubber shock mount 32 has a rubber core 34 sandwiched between a pair of steel mounting plates 36. The outer side of one of the pair of mounting plates 36 is secured to the wheel axle, and the outer side of the other mounting plate 36 is secured to a front fork 38 in which the front wheel 113 is mounted, as shown in Figure 6. Thus the pair of rubber shock mounts 32 acts as a suspension for the front fork 38 of the mobility vehicle 111.

With reference to Figures 9a and 9b, the rod linkage system 40 for connecting the stabilising wheels 14 to the front wheel 113 for the mobility vehicle 111 is similar to that used for the mobility vehicle 11 shown in Figure 3, except that link points 42 are adapted so as to enable the non-acting stabilising wheel 14a to turn inwards in relation to the front wheel 113. The stabilising wheel that is brought into use during tipping of the mobility vehicle 111 , called the acting stabilising wheel 14b, turns the same angle as the front wheel 113. By arranging for the non-acting stabilising wheel 14a to turns inwards during use, more space can be freed up for the feet placement area, as the stabilising wheels 14a, 14b will not encroach into the foot areas for the rider.

Although the invention has been shown and described with respect to a best mode embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions in the form and detail thereof may be made therein without departing from the scope of the invention as claimed.

Claims

1. A three-wheeled mobility vehicle having a pair of rear wheels, a front wheel and a seat, the vehicle comprising: at least two stabiliser wheels, with at least one stabiliser wheel lying on each side of the front wheel; and a pair of footrests, each positioned on either side of the front wheel between the front wheel and the corresponding stabiliser wheel, wherein each stabiliser wheel has an axis of rotation that crosses substantially perpendicularly through a planar area bounded by the circumference of the front wheel.

2. A vehicle according to Claim 1 , wherein the stabiliser wheels share a common axis of rotation that is parallel to and lies substantially below the axis of rotation of the front wheel with respect to the orientation of the vehicle in use.

3. A vehicle according to Claim 1 or 2, wherein the stabiliser wheels have a track width that is substantially comparable to the track width of the rear wheels.

4. A vehicle according to Claim 1 or 2, wherein the stabiliser wheels have a track width that is in the range of 70% to 100% of the track width of the rear wheels.

5. A vehicle according to Claim 1 or 2, wherein the stabiliser wheels have a track width that is substantially 90% of the track width of the rear wheels.

6. A vehicle according to any one of Claims 1 to 5, wherein the pair of footrests are pivotally connected to the frame of the vehicle, and are pivotally adjustable.

7. A vehicle according to any one of Claims 1 to 6, wherein the footrests are adjustable so that the distance of the footrests from the seat of the vehicle may be adjusted.

8. A vehicle according to anyone of Claims 1 to 7, wherein the pair of footrests are individually adjustable.

9. A vehicle according to any one of Claims 1 to 8, wherein the stabiliser wheels are castors that are revolvable in a plane parallel to the longitudinal motion of the vehicle straight ahead in use.

10. A vehicle according to Claim 9, wherein the castors are fixed so that they do not revolve laterally with respect to the direction of motion of the vehicle.

11. A vehicle according to any one of Claims 1 to 10, wherein the front wheel has a diameter substantially smaller than the diameter of the rear wheels.

12. A vehicle according to Claim 11 , wherein the front wheel has a diameter substantially in the range of 150mm to 170mm.

13. A vehicle according to Claim 11 or 112, wherein the stabiliser wheel that is non-acting, in use during tipping, is operable to turn in towards the front wheel.

14. A mobility vehicle substantially as hereinbefore described with reference to the accompanying Figures 3, 4a, 4b, 8a and 8b.

15. A mobility vehicle substantially as hereinbefore described with reference to the accompanying Figures 5, 6, 7, 9a and 9b.