Handle bar suspension

Abstract

A suspension assembly for a mobility scooter comprising: a steering column for connecting to the wheels of the mobility scooter; and a console connected to the steering column for operating the mobility scooter by a user, wherein the console and the steering column are connected to each other exclusively via a bushing arrangement comprising at least one bushing, the bushing being rigidly attached at one end of the bushing to the console and at the other end of the bushing to the steering column.

Description

[0001] HANDLE BAR SUSPENSION

[0002] This invention relates to a suspension assembly for a mobility scooter. In particular, the invention relates to a bushing arrangement between a steering column and console of the suspension assembly.

[0003] Background of the Invention

[0004] Traditional mobility scooters, as typically used by the elderly, disabled or infirm, are manufactured in two formats: three-wheeled versions and four wheeled versions. In each version, two of the wheels are at the rear of the vehicle, the remaining wheel(s) being at the front of the vehicle. The front wheel(s) are connected to a steering column, which is in turn connected to a console. The console is configured such that the user of the vehicle can control and steer the vehicle. In this regard, the console will typically comprise handlebars, a visual display (displaying a current speed of the vehicle etc) and wing mirrors.

[0005] During driving of the vehicle, vibrations are transferred through the front wheels of the vehicle, up along the steering column (which is connected to the front wheels), and to the console of the vehicle. These vibrations occur during normal road use of the vehicle and more so as a result of large bumps in the road. These vibrations make it very difficult for a user to read the visual indicators of the console and to observe the wing mirrors, which is dangerous. Vibrations from the console also pass through the handles to the user’s hands and arms, making the use of the vehicle very uncomfortable. This makes it more difficult for the user to operate the console. For example, the user may struggle to operate a particular button on the console and / or steer the vehicle, which is also dangerous.

[0006] The present invention aims to overcome or at least ameliorate one or more of the problems set out above.

[0007] Summary of the Invention

[0008] In a first aspect of the invention, there is provided a suspension assembly for a mobility scooter comprising: a steering column for connecting to the wheels of the mobility scooter; and a console connected to the steering column for operating the mobility scooter by a user, wherein the console and the steering column are connected to each other exclusively via a bushing arrangement comprising at least one bushing, the bushing being rigidly attached at one end of the bushing to the console and at the other end of the bushing to the steering column.

[0009] The arrangement of the bushing(s) between the steering column and console dampens received vibrations from the steering column that are generated during driving of the mobility scooter. In this way, a user is better able to use the console (e.g., see the visual display, observe the wing mirrors, steer the vehicle etc, all of which would otherwise have been more difficult due to vibrations). Further, the bushings are cheaper, easier to install (reducing manufacturing time) and less prone to erosion over time (relative to conventional springs that are used as dampers at a wheel fork).

[0010] Preferably, the bushing arrangement comprises two or more bushings. The bushings may be spatially arranged such that, in use, the bushings are arranged to constrain lateral movement of the console to a longitudinal direction of the mobility scooter. In a preferrable arrangement, the bushings are positioned along a longitudinal axis of the console. Preferably, one of the bushings is located at a distal end of an interface between the console and the steering column, and another bushing is located at a proximal end of an interface between the console and the steering column. In this way, the console is thus arranged to rock back and forth (i.e. , undergo a pitch movement) in a longitudinal direction of the interface between the console and steering column during use, when accommodating vibrations and under load by the user’s hands on the handlebars. This rocking motion is more stable and comfortable for a user relative to the console rocking left to right, or in all directions.

[0011] Preferably, each bushing transversely extends, laterally, between the console and steering column, across a central longitudinal axis of the console. Preferably, each bushing extends at least 50% of the width of the interface between the console and the plate. In this way, the rocking motion produced is even more stable comfortable for a user relative to the console rocking left to right, or in all directions, which would occur if each transversely extending bushing was replaced with say two central ‘shorter’ bushings (for example, having a mostly circular shape).

[0012] In a most preferrable arrangement, the console and the steering column are attached to each other exclusively via two bushings only. This facilitates producing the desired rocking motion. More than two bushings may overly constrain the rocking motion.

[0013] In one arrangement, each bushing comprises one or more bolts, each bolt being fixed between the console steering column. In another arrangement, the bushing comprises a bolt that is fixed between the console steering column. This bolt fixing limits the maximal vertical movement of the bushing at rest.

[0014] Preferably, the bolt is a shoulder bolt. In this way, friction between the bolts and surrounding bushing is reduced, improving the flexing ability of the bushing and reducing potential frictional damage.

[0015] In a preferred arrangement, the bushing comprises a polyurethane material. The polyurethane material may comprise a thermoplastic polyurethane material (TPU) or a thermoplastic elastomer material (TPE). Preferably, the bushings comprise a shore hardness of between 70 to 95A, more preferably 80A. In this way, the bushing is able to suitably flex, allowing the console to move relative to the steering column, which dampens received vibrations from the steering column that are generated during driving of the mobility scooter. In other words, the bushing comprises a material that allows compression (i.e., to flex). Mostly preferably, this material is also resistant to cracking.

[0016] In a second aspect of the invention, this is provided a mobility scooter comprising the suspension assembly according to any of claims 1 to 13.

[0017] Preferably, the mobility scooter comprises: one or more rear wheels; and three front wheels. In a most preferrable arrangement, the three front wheels comprise: a first front wheel located in the centre at the front of the mobility scooter; and second and third front wheels located either side of the first front wheel.

[0018] The bushing(s) are particularly advantageous to use as a suspension assembly in this arrangement because there is limited space in the central wheel fork area housing (due to the additional wheels). There is therefore not enough space in the central wheel fork area housing to use conventional dampers, such as springs, in a conventional way, such as on the main central wheel, or on or above the front wheel fork. To incorporate conventional dampers in this way, a large amount of space is required in the wheel fork area, which negatively affects the housing space, the foot space of the user and the turning space of the mobility scooter. Further, using conventional dampers in the wheel fork area would be detrimental to the ride quality of the mobility scooter. This is because springs in this area cause a minimal reduction in vibration and under breaking load a spring in this area would cause the front end to ‘dive’. It would therefore not be possible (or be extremely difficult and complex) to use conventional spring dampers in the wheel fork area of a mobility scooter having three front wheels.

[0019] In one arrangement, the mobility scooter further comprises a steer adjustment mechanism for adjusting the steer angle and the height of the second and third front wheels depending on the steer angle of the first front wheel, the adjustment mechanism being configured such that: when the first front wheel has a straightahead steer angle, the steer angles of the second and third front wheels are also straight-ahead and all three front wheels are in contact with the ground; and when the steer angle of the first front wheel is turned such that motion of the vehicle would describe a curve, the steer angle of the front wheel on the outside of said curve is turned at least partly towards the steer angle of the first front wheel, the steer angle of the front wheel on the inside of said curve is not substantially turned towards the steer angle of the first front wheel, and the height of the front wheel on the inside of said curve is raised relative to the height of the front wheel on the outside of said curve, the first front wheel and the front wheel on the outside of said curve remaining in contact with the ground. The bushing(s) are even more advantageous to use as a suspension assembly in this arrangement because the limited space issue is compounded if the outer wheels are configured to lift off the ground into the central wheel fork area housing. The use of conventional dampers (such as springs) because even more difficult and complex (if not impossible).

[0020] Brief Description of the Drawings

[0021] Embodiments of the invention will now be described by way of example, with reference to the drawings in which:-

[0022] Figure 1 a is a side view illustrating a mobility scooter, and Figure 1 b is front view illustrating a mobility scooter.

[0023] Figure 2a is a plan view of a steering mechanism of the wheels of the mobility scooter, and Figure 2b is a plan view of the central wheel being turned.

[0024] Figure 3 is a front perspective view of Figure 2b.

[0025] Figure 4 is a perspective view illustrating a console and steering column of the mobility scooter of Figure 1 .

[0026] Figure 5a is the view of Figure 2 without casings showing a bushing arrangement between the console and steering column, and Figure 5b is a side view of Figure 2, again without casings, showing the bushing arrangement.

[0027] Figure 6 is a perspective cross-sectional view showing the bushing arrangement.

[0028] Detailed Description

[0029] With reference to Figures 1 a and 1 b, a mobility scooter 10 comprises a body 12 having a seat 14 for a user (not shown). Rear-end wheels 16 are provided at a rear of the scooter (not visible in Figure 1 b) and front-end wheels 18 are provided at a front of the scooter.

[0030] In this embodiment, the scooter 10 has five ground-engaging wheels. The rear- end wheels 16 comprise two rear wheels, which are driven, for example, by a battered-powered motor situated beneath the seat of the scooter 10. The frontend wheels 18 comprise three wheels: a steerable central wheel 20 located in the centre at the front of the scooter 10, and outer wheels 22a, 22b located either side of the central wheel 20. The wheels 20, 22a, 22b are steered via a rotatable shaft 30 (visible mostly clearly in Figures 2a and 4a) by operation of handlebars 24 (or other steering means arranged to receive input from a user, such as a joystick, or one or more levers, buttons or paddle controls etc).

[0031] As illustrated in Figure 4, the handlebars 24 form part of a console 26 of the scooter 10, which is attached to the shaft 30 via a steering column 28. In this embodiment, the console 26 provides various functions for the user to control the mobility scooter (electrical controls etc), as well as a visual display and wing mirrors (not shown). In some embodiments, the console may comprise only handlebars to control the steering of the front-end wheels 18. In this case, the control of the motor may be achieved directly via the handlebars alone. In some embodiments, two distinct handlebars are provided, but in other embodiments, one handlebar is provided that accommodates both of the users hands for steering the wheels 18.

[0032] In this document, the term ‘console’ means a panel or unit accommodating a set of controls for electronic and / or mechanical equipment. Thus, a console providing little or no functions for controlling the mobility scooter, but provides only handlebars is a console as per this definition, as it provides for control of the steering of the wheels (i.e., mechanical equipment) and the motor (electromechanical equipment etc).

[0033] The steering column 28 is rigidly attached to the shaft 30, and thus rotatable about the axis of the shaft 30. In this way, the console 26 can be rotated about the axis of the shaft 30 to steer the front-end wheels 18. The connection between the console 26 and steering column 28 will be described later on.

[0034] In this embodiment, the front-end wheels 18 are arranged (via a steer adjustment means) such that the steer angle and height of the outer wheels 22a, 22b is dependent on the steer angle of the central wheel 20. More specifically, the steer adjustment means is configured such that when the central wheel 20 has a straight ahead steer angle, so to do the outer wheels 22a, 22b - all three of these wheels are in contact with the ground. When the steer angle of the central wheel 20 is turned (so that motion of vehicle described a curve), the steer angle of the outer wheel on the outside of the curve is turned towards the steer angle of the central wheel 20, and the steer angle of the outer wheel on the inside of the curve is not turned towards to the steer angle of the central wheel 20. Further, as illustrated in Figure 3, at the same time, the height of the outer wheel on the inside of the curve is raised relative to the outer wheel on the outside of the curve, while the central wheel 20 and outer wheel on the outside of the curve remain in contact with the ground. Figure 2b illustrates the central wheel 20 being turned right, which causes the outer wheel 22a to lift off the ground and the steer angle of the outer wheel 22b to turn towards the steer angle of the central wheel 20 (i.e., also right).

[0035] In other, less preferrable embodiments, the steer angle of all the front-end wheels 18 is adjusted in tandem via the shaft 30.

[0036] As illustrated in the plan view of Figure 2a, the steer adjustment means comprises a U-shaped frame 32 which surrounds the central wheel 20 and is connected at its distal ends to the outer wheels 22a, 22b. A central portion of the frame 32 is connected to the chassis of the mobility scooter via a horizontal pivot axis 34. The frame is mounted at 5 degrees to the horizontal. In this way, the frame 32 is able to pivot horizontally about the pivot axis 34 to raise / lift one of the outer wheels 22a, 22b off the ground.

[0037] The central wheel 20 is connected to the shaft 30 via a wheel fork 36 (seen in Figure 3). A guide wheel 38 is also connected to the shaft 30 via a curved joint 40 which follows the curvature of the central wheel 20. The joint 40 is connected to the shaft such that there is a clearance between the joint 40 and wheel 20. The guide wheel 38 contacts a top surface of the frame 32. Thus, rotating the shaft 30 (via the handlebars 24) causes the central wheel 20 to pivot about the axis of the shaft 30, and the guidewheel to track along the frame 32. The outer wheels 22a, 22b are arranged to move vertically relative to the frame 32 via vertical pillars 42 (seen in Figure 3). In this way, the frame 32 pivots horizontally when the central wheel 20 is turned (i.e., due to the action of wheel 38 against the frame 32). The frame 32 may be regarded as a cam and the wheel 38 as a cam follower. For the steer angle of the outer wheels 22a, 22b, each wheel is arranged to pivot horizontally relative to the frame 32 via a pivot axis 44. Telescopic rods 46 and retaining springs 48 connected between each outer wheel and the wheel fork 36 are arranged to cause the desirable steer angles of each of the front-end wheels 18 described earlier.

[0038] For clarity, Figures 5a and 5b illustrate the handlebars 24 without the rest of the components of the console 26, and the steering column 28 without an outer casing (shown in Figure 4). The handlebars 24 curve inwardly towards the seat 14 of the mobility scooter 10, and are mounted to a console bracket 50, which comprises a flat plate 52. The steering column 28 is formed via two vertical stems 54a, 54b connected between a top bracket 56 and a bottom bracket 58, the bottom bracket 58 being rigidly connected to the shaft 30. The top bracket 56 comprises a flat plate 60.

[0039] The console plate 52 is exclusively connected to the column plate 60 via a first bushing 62 and a second bushing 64. Each bushing 62, 64 comprises a transversely extending stadium-type shape (i.e., a rectangle with semicircles at a pair of opposite sides) and is fixed between the plates 52, 60 via two bolts, one bolt at each transverse end of the bushing. In some embodiments, the bushings may have a different shape (e.g., such as rectangular, ovoid, circular). The plates 52, 50 thus define an interface between the console 26 and steering column 28.

[0040] The bolts pass freely through holes in each of the plates 52, 60, the head of each bolt being secured against one plate (in this embodiment plate 60) and the other plate (in this embodiment plate 52) via a nut (visible in Figure 5a). In this way, the first and second bushings 62, 64 are constrained in their vertical axis, connect the console 26 (which comprises the handlebars 24) to the steering column 28 and constrain relative movement between the console 26 and the steering column 28.

[0041] Preferably, the bolts are shoulder bolts. In this way, friction between the bolts and surrounding bushing is reduced, improving the flexing ability of the bushing and reducing potential frictional damage. This is because the shoulder bolt comprises a smooth neck surface (rather than a threaded neck surface provided by conventional bolts). Normal threaded bolts could be used, but are less preferrable due to increased friction.

[0042] Figure 6 illustrates a cross-sectional view of an embodiment with a bushing arrangement comprising four bushing. Figure 6 shows bolts 66, 68 passing through bushings 62, 64 respectively. In this embodiment, each bushing has a circular shape. In this embodiment, each transversely extending bushing of the embodiment of Figures 5a and 5b is replaced by two bushings positioned next to each other, laterally, so as to transversely extend between the plates 52, 60 in a similar manner to the above described embodiment. The four bushings are thus arranged into rows, each row having two bushings, each bushing being fixed between the plates 52, 60 via a bolt.

[0043] In this document, the term ‘exclusively’ means there are no fixing points between the console 26 (more specifically the console plate 52) and the steering column 28 (more specifically the column plate 60) other than the first and second bushings, which include the bolts. So, there are no other fixing elements that constrain the movement between the console 26 the steering column 28. In embodiments where there are more or less bushings that two bushings, this is also the case. In other words, in all embodiments, the console 26 and steering column are attached to each other exclusively (i.e., solely or only etc) via a bushing arrangement.

[0044] Each bushing comprises a material that allows compression but is resistant to cracking, such as a polyurethane material. The bushing is thus able to flex, allowing the console 26 to move relative to the steering column 28, which dampens received vibrations from the steering column that are generated during driving of the mobility scooter. In this way, a user is better able to use the console (e.g., see the visual display, observe the wing mirrors, steer the vehicle etc, all of which would otherwise have been more difficult due to vibrations). Preferably, the polyurethane material is a thermoplastic polyurethane material (TPU) or a thermoplastic elastomer material (TPE). In this embodiment, the material of the bushing has a shore hardness of between 70-95A. In this way, the material allows compression but is resistant to cracking. More preferably, the material of the bushing has a shore hardness of 80A.

[0045] In the embodiment of Figures 5a and 5b, each bushing 62, 64 transversely extends across most of the width of the plates 52, 60. The bushings also extend across (i.e., either side of) a central longitudinal axis of the plates. In this way, the bushings support both sides (i.e., left side and right side) of the console 26. The first bushing 62 is located (or fixed) at a distal end of the plates 52, 60 (or interface between the console and steering column) and the second bushing 64 is located (or fixed) at a proximal end of the plates 52, 60 (or interface between the console and steering column. Distal and proximal in this context means relative to a central axis of the mobility scooter.

[0046] Having two bushings spatially arranged in this way is particularly advantageous because the console 26 is thus arranged to rock back and forth (i.e., undergo a pitch movement) in a longitudinal direction of the plates 52, 50 during use, when accommodating vibrations and under load by the user’s hands on the handlebars 26. This rocking motion is more stable and comfortable for a user relative to the console rocking left to right, or in all directions, which would occur if each transversely extending bushing was replaced with two central ‘shorter’ bushings (for example, having a mostly circular shape). The bushing 64 located at the proximal end of the console / plates flexes the most under loading, due to the nature of the user gripping the handles, creating a pivot on the bushing located at the distal end of the console / plates. In other words, the bushings are arranged to significantly constrain lateral movement of the console to a longitudinal direction of the mobility scooter.

[0047] In a less preferrable embodiment, the bushing arrangement comprises one central bushing. This may be a ‘shorter’ circle shaped bushing having one bolt, or more preferably, a transversely extending elongate shaped bushing having two bolts. In some embodiments, the bushing arrangement comprises more than two transversely extending bushings (such as three bushing, or four bushings and so on). In these embodiments, preferably, each bushing is transversely arranged along a central longitudinal axis of the console (or more specifically, the plates 52, 60). So, for a bushing arrangement having three bushings, the third bushing would be arranged between the distal bushing 62 and the proximal bushing 64, and so on. However, each additional bushing to this arrangement would attenuate the desired back and forth rocking motion, so a bushing arrangement having two bushings is most preferrable.

[0048] In other embodiments, such as the one of Figure 6, the transversely extending bushings are replaced with rows of two or more ‘shorter’ bushings (such as circle shaped).

[0049] The arrangement of the bushings 62, 64 between the steering column 28 and console 26 thus defines a suspension assembly of the mobility scooter to dampen vibrations that occur during use. When the mobility scooter has a three front wheel arrangement, as in the preferred described embodiment, the described bushings are particularly advantageous to use as a suspension assembly because there is limited space in the central wheel fork area housing (due to the additional wheels). This is compounded if the outer wheels 22a, 22b are configured to lift off the ground into the central wheel fork area housing (as in the preferred described embodiment of Figure 3).

[0050] There is therefore not enough space in the central wheel fork area housing to use conventional dampers, such as springs, in a conventional way, such as on the main central wheel, or on or above the front wheel fork. To incorporate conventional dampers in this way, a large amount of space is required in the wheel fork area, which negatively affects the housing space, the foot space of the user and the turning space of the mobility scooter. Further, using conventional dampers in the wheel fork area would be detrimental to the ride quality of the mobility scooter. This is because springs in this area cause a minimal reduction in vibration and under breaking load a spring in this area would cause the front end to ‘dive’.

[0051] These disadvantages are overcome by exclusively using bushings between the console and steering column as a suspension assembly. Further, the bushings are cheaper, easier to install (reducing manufacturing time) and less prone to erosion over time.

Claims

CLAIMS1 . A suspension assembly for a mobility scooter comprising: a steering column for connecting to the wheels of the mobility scooter; and a console connected to the steering column for operating the mobility scooter by a user, wherein the console and the steering column are connected to each other exclusively via a bushing arrangement comprising at least one bushing, the bushing being rigidly attached at one end of the bushing to the console and at the other end of the bushing to the steering column.

2. A suspension assembly according to claim 1 , wherein the bushing arrangement comprises two or more bushings.

3. A suspension assembly according to claim 2, wherein the bushings are spatially arranged such that, in use, the bushings are arranged to constrain lateral movement of the console to a longitudinal direction of the mobility scooter.

4. A suspension assembly according to any of claims 2 to 3, wherein the bushings are positioned along a longitudinal axis of the console.

5. A suspension assembly according to any of claims 2 to 4, wherein one of the bushings is located at a distal end of an interface between the console and the steering column, and another bushing is located at a proximal end of an interface between the console and the steering column.

6. A suspension assembly according to any of claims 2 to 5, wherein each bushing transversely extends, laterally, between the console and steering column, across a central longitudinal axis of the console.

7. A suspension assembly according to any of claims 2 to 6, wherein the console and the steering column are attached to each other exclusively via two bushings only.

8. A suspension assembly according to any of claims 6 to 7, wherein each bushing comprises one or more bolts, each bolt being fixed between the console steering column.

9. A suspension assembly according to claim 1 , wherein the bushing comprises a bolt that is fixed between the console steering column.

10. A suspension assembly according to claim 8 or 9, wherein the bolt is a shoulder bolt.

11. A suspension assembly according to any preceding claim, wherein the bushing comprises a polyurethane material.

12. A suspension assembly according to claim 1 1 , wherein the polyurethane material comprises a thermoplastic polyurethane material (TPU) or a thermoplastic elastomer material (TPE).

13. A suspension assembly according to claim 1 1 or claim 12, wherein the bushing comprise a shore hardness of between 70 to 95A, more preferably 80A.

14. A mobility scooter comprising the suspension assembly according to any preceding claim.

15. The mobility scooter according to claim 14, wherein the mobility scooter comprises: one or more rear wheels; and three front wheels.

16. The mobility scooter according to claim 15, wherein the three front wheels comprise: a first front wheel located in the centre at the front of the mobility scooter; andsecond and third front wheels located either side of the first front wheel.

17. The mobility scooter according to claim 16, further comprising a steer adjustment mechanism for adjusting the steer angle and the height of the second and third front wheels depending on the steer angle of the first front wheel, the adjustment mechanism being configured such that: when the first front wheel has a straight-ahead steer angle, the steer angles of the second and third front wheels are also straight-ahead and all three front wheels are in contact with the ground; and when the steer angle of the first front wheel is turned such that motion of the vehicle would describe a curve, the steer angle of the front wheel on the outside of said curve is turned at least partly towards the steer angle of the first front wheel, the steer angle of the front wheel on the inside of said curve is not substantially turned towards the steer angle of the first front wheel, and the height of the front wheel on the inside of said curve is raised relative to the height of the front wheel on the outside of said curve, the first front wheel and the front wheel on the outside of said curve remaining in contact with the ground.

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