GB2546242A

GB2546242A - A tricycle

Info

Publication number: GB2546242A
Application number: GB1522127.8A
Authority: GB
Inventors: David Harrison Norman; Harrison Mark
Original assignee: Mph Support Ltd
Current assignee: Mph Support Ltd
Priority date: 2015-12-15
Filing date: 2015-12-15
Publication date: 2017-07-19
Anticipated expiration: 2035-12-15
Also published as: GB201522127D0; GB2546242B

Abstract

A tricycle I comprises a left front wheel 2, a right front wheel 5, a steering column 6connected to both the left front wheel 2 and the right front wheel 5 such that a user can steer the tricycle 1 by turning the steering column 6, and stabilising apparatus 9comprising a left link 25 and a right link 26, each link 25, 26 connected to the steering column 6. The left link 25 is indirectly connected to the left front wheel 2 and the right link 26 is indirectly connected to the right front wheel 5, such that turning the steering column 6 to the left or right raises the respective connected left link 25 or right link 26, thereby raising the respective connected left front wheel 2 or right front wheel 5, thereby instigating a lean into the turn. Suspension may be provided by left and right suspension units 23,24.

Description

A TRICYCLE

Technical Field of the Invention

The present invention relates to a tricycle. In particular, the present invention relates to a tadpole tricycle comprising stabilising apparatus for addressing the problem of the tricycle’s frame and rider leaning outwardly away from a corner when steering into the comer.

Background to the Invention A tricycle is a three-wheeled vehicle. T ricycles typically have one of two different wheel configurations; two front wheels and one rear wheel (a tadpole tricycle) or one front wheel and two rear wheels (a delta tricycle).

Tricycles are used for recreation, exercise and competitive sport and may be preferred over a bicycle due to their increased stability, which is provided by having three points of contact with the ground. A tadpole tricycle may be preferred over a delta tricycle due to its ability to include a wide range of bicycle transmission and gear components, its improved braking performance and its aesthetics.

Figures 1, 2 and 3 show a known tadpole tricycle 1 comprising a left front wheel 2 rotatable about a left axle 3 and a right front wheel 5 rotatable about a right axle 4. The left axle 3 and the right axle 4 are connected to a steering column 6 so that the tricycle can be steered by turning the steering column 6. A frame 7 comprises a head tube 32 housing the steering column 6. The frame 7 connects to a rear axle having a rotatable rear wheel 8. A number of other known parts of the tricycle are omitted to improve the clarity of Figures 1, 2 and 3. The view in Figures 2 and 3 are from view point “X” in Figure 1.

Figure 3 shows that when a user turns the steering column 6 to the left in order to steer the tricycle 1 left, the frame 7 has a tendency to lean or tilt outwards to the right, which is opposite to the turn direction. This causes an unusual and unsafe off-balance sensation for the user of the tricycle, which can result in injury due to the user falling off.

This outwards lean whilst turning is caused by the geometry of the tadpole tricycle. In particular, it is related to the angle of the head tube of the tricycle and the three points of contact with the ground. The head tube 32 typically slopes backwards towards the user, similar to bicycle frame design, in order to create trail or caster which improves handling and stability. If the angle of the head tube is decreased then handling typically improves, to a point, but the outwards tilt problem worsens. Similarly, if the angle of the head tube is increased, towards vertical, then handling typically worsens, but the outwards tilt problem is reduced.

Accordingly, one conventional way to address this problem is to use a vertically oriented head tube exactly ninety degrees to the horizontal. However, this arrangement severely impacts on the handling and stability of the tricycle in motion. In addition, with a vertical head tube it is still not possible to lean the tricycle into a turn, which would further improve handling and stability and allow for safe high speed cornering.

Embodiments of the present invention seek to address the above problems. Summary of the Invention

According to a first aspect of the invention, there is provided a tricycle comprising: a left front wheel, a right front wheel, a steering column connected to both the left front wheel and the right front wheel such that a user can steer the tricycle by turning the steering column, and stabilising apparatus comprising a left link and a right link, each link connected to the steering column. The left link is connected to the left front wheel and the right link is connected to the right front wheel, such that turning the steering column to the left or right raises the respective connected left link or right link, thereby raising the respective connected left front wheel or right front wheel.

In this way, the stabilising apparatus is arranged to pull up and raise the inside axle and wheel when a user executes a turn. This adjusts the geometry of the tricycle to counteract the tendency for the tricycle to tilt outwards when turning. Specifically, raising the inside wheel when turning tilts the frame of the tricycle towards the turn which offsets the natural outwards lean. Indeed, the tricycle may be configured to significantly raise the inside wheel in order for the tricycle to lean into the turn. The rider can also create more lean into the turn by shifting his weight in a similar way to a bicycle rider. Accordingly, the tricycle has improved handling and stability when turning and may remain substantially upright, even when the user executes a tight turn, or may even lean into a turn when turning at a relatively high speed. Consequently, the safety of the tricycle is improved and the user no longer experiences any unusual or precarious sensations when turning.

It will be appreciated that the wheel is raised upwardly relative to the steering column, not necessarily (or even desirably) raised off the ground.

The left link may be indirectly connected to the left front wheel. The right link may be indirectly connected to the right front wheel.

The left front wheel and right front wheel may be rotatable about a single axle. Alternatively, the left front wheel may be rotatable about a left axle, and the right front wheel may be rotatable about a right axle. In this way, the axles have independent vertical movement whilst working together to steer in compliance with Ackermann steering rules which avoids tyre scrub and ensures smooth steering.

The left front wheel and the right front wheel may be connected to the steering column by a track rod and axle system.

The left link may be connected to the single axle. The right link may be connected to the single axle. Alternatively, the left link may be connected to the left axle and the right link may be connected to the right axle. In this way, turning the steering column to the left or right raises the respective connected left link or right link, which raises the respective connected left axle or right axle, thereby raising the respective left front wheel or right front wheel.

The tricycle may be a human-powered tricycle. The tricycle may be a pedal tricycle. The tricycle may be powered by a motor. In particular, the tricycle may be powered by an electric motor. The tricycle may be a tadpole style tricycle, which has two front wheels and one rear wheel. The tricycle may be an upright tricycle. The tricycle may be a recumbent tricycle.

The tricycle may further comprise a pair of handlebars attached to the steering column to assist the user in turning the steering column to steer the tricycle.

The tricycle may further comprise a frame headtube for housing the steering column.

The stabilising apparatus may further comprise a collar attached around the steering column. In this way, the collar turns as the steering column is turned by a rider. The collar may be substantially cylindrical. The collar may have a substantially circular cross section in a plane substantially perpendicular to and centred about the axis of rotation. The collar may be substantially elliptically cylindrical. The collar may have a substantially oval or elliptical cross section in a plane substantially perpendicular to and centred about the axis of rotation.

The left link and/or the right link may be an arm. The left link and/or the right link may comprise a cable. The left link and/or the right link may comprise a rod. The left link and/or the right link may comprise a chain. The left link and/or the right link may comprise a series of toothed wheels. The left link and/or the right link may be connected to the steering column by being attached to the collar directly, or with an intervening member.

The stabilising apparatus may further comprise a central support. The central support may be mounted parallel to the steering column and/or the frame headtube. The central support may be oriented substantially vertically.

The stabilising apparatus may further comprise a left stabilising structure for stabilising the left front wheel and a right stabilising structure for stabilising the right front wheel. The two stabilising structures may work in tandem for stabilising both front wheels at the same time.

In particular, the left stabilising structure may comprise a top arm, a base arm and a side arm. The top arm and/or the base arm may be oriented substantially horizontally. The base arm may be positioned below and substantially in line with the top arm. Thus, the base arm and top arm may be parallel to each other. The side arm may be oriented substantially vertically, and thus may be parallel to the central support. The base arm and/or the top arm may be pivotally connected to the central support or the frame head tube at one end and pivotally connected to the side arm at an opposing end. The right stabilising structure may comprise all or any feature of the left stabilising structure. In this way, the left stabilising structure and/or the right stabilising structure may be an adjustable, parallelogram shaped structure that is independent, and moveable, or pivotable, about the central support or frame head tube.

The left top arm, left base arm, left side arm, central support, right top arm, right base arm and/or right side arm may be elongate.

The stabilising apparatus may further comprise a tilt bar. The tilt bar may be elongate and/or planar. The tilt bar may be formed from a single piece of material, thus the tilt bar may be rigid. The tilt bar may be connected to the steering column such that the tilt bar turns as the steering column is turned. The tilt bar may be pivotally connected to the central support or frame head tube, and pivotal about the central support or frame head tube, such that the tilt bar can pivot towards and away from the left front wheel and the right front wheel. The tilt bar may be connected to the left axle and the right axle. The left link may be attached to the tilt bar, in particular to a left side of the tilt bar. The right link may be attached to the tilt bar, in particular to a right side of the tilt bar. The left link and/or the right link may be attached to opposing distal ends of the tilt bar. In this way, the left link and/or the right link may be connected to the left front wheel and the right front wheel, or the left axle and the right axle, by being attached to the tilt bar.

The tilt bar may be arranged so that, in use, it remains substantially parallel to any of the left top arm, left base arm, right top arm and/or right base arm.

The tricycle and/or the stabilising apparatus may further comprise one or more suspension units. In particular, the tricycle may further comprise two suspension units, a left suspension unit and a right suspension unit. The left suspension unit and/or the right suspension unit may comprise standard components that allow it to function and act as a shock absorber. Each suspension unit may comprise compressed hydraulic fluid or compressed air, spring and cushions. Each suspension unit may comprise of elastic rubber polymer material known as elastomer. In this way, an independent suspension unit is provided in respect of each of the left front wheel and the right front wheel.

The left suspension unit and/or right suspension unit may be pivotally connected at its top to the tilt bar. The left suspension fork may be pivotally connected at its bottom to the left base arm. The right suspension fork may be pivotally connected at its bottom to the right base arm. In this way, the suspension units may be connected so as to move the left base arm and/or the right base arm in response to movement of the tilt bar, which subsequently raises or lowers the left front wheel and/or the right front wheel.

The stabilising apparatus may be arranged to raise the left front wheel or right front wheel proportional to a turn of the steering column left or right, respectively. In particular, the stabilising apparatus may be arranged to provide a linear relationship between the turning of the steering column and the raising of the inside wheel when steering the tricycle. Alternatively, the stabilising apparatus may be arranged to raise the inside wheel with minimal turning of the steering column.

According to a second aspect of the invention, there is provided a tricycle comprising: a left front wheel rotatable about a left axle; a right front wheel rotatable about a right axle; a steering column connected to both the left axle and the right axle such that a user can steer the tricycle by turning the steering column; and stabilising apparatus comprising a left link and a right link. Each of the left link and the right link are connected at one end to the steering column. The left link is connected to the left axle and the right link is connected to the right axle, such that turning the steering column to the left or right raises the respective connected left link or right link, which raises the respective connected left axle or right axle, thereby raising the respective left front wheel or right front wheel.

Detailed Description of the Invention

In order that the invention may be more clearly understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 is a side profile view of a known tricycle with a view point “X” indicated;

Figure 2 is an overhead view of the known tricycle in Figure 1, from view point “X”;

Figure 3 is an overhead view of the known tricycle in Figure 1, from view point “X”, when the user is steering left;

Figure 4 is front view of a tricycle according to an embodiment of the invention, with no turn on the steering column;

Figure 5 is a front view of the tricycle of Figure 4, with the steering column turned to the left; and

Figure 6 is an overhead view of a tricycle according to an embodiment of the invention, from the same view point as view point “X” in Figure 1, with the steering column turned to the left.

Figure 7 is a side close-up view of Figure 4, with no turn on the steering column.

Figures 1, 2 and 3 are discussed above in the “Background to the Invention” and illustrate a tricycle according to the prior art.

Figures 4 and 5 and 7 illustrate the front of a tricycle 1 according to an embodiment of the present invention. In order to improve the clarity of the drawings, a number of conventional parts of the tricycle 1 are not shown and the left and right front wheels 2, 5 have been simplified.

The tricycle 1 comprises a left front wheel 2 rotatable about a left axle 3, and a right front wheel 5 rotatable about a right axle 4. The left axle 3 and the right axle 4 are connected to a stabilising apparatus 9, which is connected to a frame headtube 32. The frame headtube 32 houses a steering column 6, which is connected to a pair of handlebars (not shown), optionally via a stem 3 3. The left axle 3, right axle 4, steering column 6 and handlebars are all connected such that they rotate as a unit as a user turns the handlebars to a desired direction. Consequently, turning the handlebars changes the direction of the front wheels 2, 5 of the tricycle 1. A collar 10 is provided around the steering column 6, near its top where it connects to the handlebars. In this embodiment, the collar 10 has a substantially circular cross-section.

The stabilising apparatus 9 comprises a left stabilising structure 11 and a right stabilising structure 15. Each structure is formed from a series of arms connected to a central support 31 which is mounted in parallel to the frame headtube 32 to create two parallelograms.

The left stabilising structure 11 comprises a left top arm 12, a left side arm 13, and a left base arm 14. Each of the left top arm 12, left side arm 13 and left base arm 14 are substantially planar and elongate.

The left side arm 13 is oriented substantially vertically and is pivotally connected at its top end to a left end of the left top arm 12 and pivotally connected at its bottom end to a left end of the left base arm 14. The left top arm 12 is further pivotally connected at its right end to the central support 31. The left base arm 14 is further pivotally connected at its right end to the base of the central support 31. Thus, movement of one of the left top arm 12, left side arm 13 or left base arm 14 moves each arm simultaneously, relative to the central support 31 and the connected frame headtube 32.

The right stabilising structure 15 comprises a right top arm 18, a right side arm 17, and a right base arm 16. Each of the right top arm 18, right side arm 17 and right base arm 16 are substantially planar and elongate.

The right side arm 17 is oriented substantially vertically and is pivotally connected at its top end to a right end of the right top arm 18 and pivotally connected at its bottom end to a right end of the right base arm 16. The right top arm 18 is further pivotally connected at its left end to the central support 31. The right base arm 16 is further pivotally connected at its left end to the base of the central support 31. Thus, movement of one of the right top arm 18, right side arm 17 or right base arm 16 moves each arm simultaneously, relative to the central support 31 and the connected frame headtube 32.

The left axle 3 is connected to a left axle housing 19, which is attached to the base of the left side arm 13, in the region where it is pivotally connected to the left base arm 14. Similarly, the right axle 4 is connected to a right axle housing 20, which is attached to the base of the right side arm 17, in the region where it is pivotally connected to the right base arm 16.

The stabilising apparatus 9 further comprises a planar and elongate tilt bar 21, which is attached to a suspension mount 22. The tilt bar 21 and suspension mount 22 are pivotally connected at their respective centres to the central support 31, within a boundary defined by the left and right top arms 12,18, the left and right side arms 13,17 and the left and right base arms 14, 16. A left suspension unit 23 is mounted at its top to the left side of the suspension mount 22, and at its bottom to the left base arm 14. Thus, the left suspension unit 23 sits between the suspension mount 22 and the left base arm 14. A right suspension unit 24 is mounted at its top to the right side of the suspension mount 22, and at its bottom to the right base arm 16. Thus, the right suspension unit 24 sits between the suspension mount 22 and the right base arm 16.

Each of the left suspension unit 23 and the right suspension unit 24 are conventional bicycle suspension units that can absorb and dampen mechanical shock by compression. A left link 25 is attached at one of its ends to the circular collar 10 by use of collar attachment means 27. The opposite end of the left link 25 is attached to the tilt bar 21 by use of tilt bar attachment means 28. Similarly, a right link 26 is attached at one of its ends to the circular collar 10 by use of collar attachment means 28. The opposite end of the right link 26 is attached to the tilt bar 21 by use of tilt bar attachment means 29. In this embodiment, the left link 25 and the right link 26 are metal cables and the attachment means are fasteners.

The attachment means 28 and 29 are positioned on the collar so that the left link 25 and the right link 26 may be attached to the collar 10 in such a manner that rotating the collar 10 left raises the left link 25 and simultaneously drops the right link 26, and rotating the collar 10 right drops the left link 25 and simultaneously raises the right link 26.

The left link 25 and the right link 26 are attached at opposing ends of the tilt bar 21, symmetrically about the central support 31.

In use, in order to steer the tricycle 1 the user turns the handlebars, which turns connected steering column 6. This simultaneously turns the connected stabilising apparatus 9, left and right axles 3, 4 and left and right front wheels 2, 5. For example, if the user wants to steer the tricycle to the left, the user turns the handlebars left, which turns the steering column 6, stabilising apparatus 9, left and right axles 3, 4 and left and right front wheels 2, 5, to the left.

At the same time, turning the steering column 6 left causes the collar 10 to rotate left, which pulls the left link 25 upwards and drops the right link 26 downwards. This causes the connected tilt bar 21 to pivot, or tilt, about the central support 31. The left side of the tilt bar 21 is thus pulled upwards, causing the right side of the rigid tilt bar 21 to be pushed downwards.

This pivoting movement of the tilt bar 21 causes the attached suspension mount 22 to pivot in the same manner.

Thus, the left suspension fork 23 is pulled upwards, which causes the left base arm 14 to pivot upwards about the central support 31, which consequently causes the left side arm 13 to move upwards, and the left top arm 12 to pivot upwards about the central support 31.

At the same time, the right suspension fork 24 is pushed downwards, which causes the right base arm 16 to pivot downwards about the central support 31, which consequently causes the right side arm 17 to move downwards, and the right top arm 18 to pivot downwards about the central support.

The left base arm 14 pivots simultaneously with, and by the same angle as, the left top arm 12. Thus, the left base arm 14 remains parallel to the left top arm 12 as they both pivot, and the left side arm 13 remains parallel to the central support 31 as its moves upwards. Similarly, the right base arm 16 pivots simultaneously with, and by the same angle as, the right top arm 18. Thus, the right base arm 16 remains parallel to the right top arm 18 as they both pivot, and the right side arm 17 remains parallel to the central support 31 as its moves downwards. Consequently, the parallelogram shapes of the left stabilising structure 11 and the right stabilising structure 15 are maintained when the tricycle turns.

The upward movement of the left side link 13 also moves the attached left axle housing 19 upwards, raising the left axle 3 and thus the left front wheel 2. Similarly, the downwards movement of the right side link 17 also moves the attached right axle housing 20 downwards, lowering the right axle 4 and thus the right front wheel 5.

Accordingly, by turning the handlebars to the left, the left front wheel 2 is raised relative to the central support 31 and the right front wheel 5 is lowered relative to the central support 31. The geometry of the tricycle 1 is therefore changed compared to when a conventional tricycle turns.

Consequently, when the tricycle 1 is riding on a surface such as a road, the weight of the rider and the tricycle 1 cause the tricycle 1 to tilt to the left as the handlebars are turned left. This inward tilt offsets and counteracts the natural outward tilt caused by the geometry of the tricycle 1, which allows the frame 7 of the tricycle 1 to remain upright when turning, as is shown in Figure 6. Indeed, in some embodiments the collar 10 may be configured to prompt greater vertical movement of the left and right links 25, 26, which can be used to allow the tricycle 1 to lean into a turn.

When the handlebars are turned back to their centre position, so that the left and right front wheels, 2, 5 face forwards, the above movements are reversed. As a result, the left axle 3 and left front wheel 2 lower back to their normal riding position and the right axle 4 and right front wheel 5 rise back to their normal riding position.

It should be noted that during a right hand turn the various components of the tricycle 1 would move and function oppositely to the use as described above, with reference to a left hand turn, as would be understood by a person skilled in the art.

The above embodiment is described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A tricycle comprising: a left front wheel; a right front wheel; a steering column connected to both the left front wheel and the right front wheel such that a user can steer the tricycle by turning the steering column; and stabilising apparatus comprising a left link and a right link, each link connected to the steering column, wherein the left link is connected to the left front wheel and the right link is connected to the right front wheel, such that turning the steering column to the left or right raises the respective connected left link or right link, thereby raising the respective connected left front wheel or right front wheel.

2. A tricycle according to claim 1, wherein the left front wheel and right front wheel are rotatable about a single axle.

3. A tricycle according to claim 1, wherein the left front wheel is rotatable about a left axle and the right front wheel is rotatable about a right axle.

4. A tricycle according to claim 3, wherein the steering column is connected to the left front wheel by being connected to the left axle and connected to the right front wheel by being connected to the right axle.

5. A tricycle according to claim 3 or claim 4, wherein the left link is connected to the left axle and the right link is connected to the right axle.

6. A tricycle according to any preceding claim, wherein the tricycle is a human-powered pedal tricycle or an electric motor assisted tricycle.

7. A tricycle according to any preceding claim, wherein the stabilising apparatus further comprises a collar attached around the steering column.

8. A tricycle according to claim 7, wherein the left link and/or the right link is connected to the steering column by being attached to the collar.

9. A tricycle according to any preceding claim, wherein the left link and/or the right link comprises a cable.

10. A tricycle according to any one of claims 1 to 8, wherein the left link and/or the right link comprises a rod.

11. A tricycle according to any preceding claim, wherein the stabilising apparatus further comprises a central support.

12. A tricycle according to claim 11, wherein the stabilising apparatus further comprises a left stabilising structure for stabilising the left front wheel and aright stabilising structure for stabilising the right front wheel.

13. Atricycle according to any claim 12, wherein the left stabilising structure works in tandem with the right stabilising structure for stabilising both front wheels at the same time.

14. A tricycle according to any one of claims 11 to 13, wherein the left stabilising structure and/or the right stabilising structure each comprise a parallelogram shaped structure that is pivotable about the central support.

15. A tricycle according to any preceding claim, wherein the stabilising apparatus further comprises a tilt bar.

16. A tricycle according to claim 15, wherein the tilt bar is connected to the left axle and the right axle.

17. A tricycle according to claim 15 or claim 16 when dependent on any one of claims 11 to 14, wherein the tilt bar is pivotally connected to the central support, and pivotal about the central support, such that the tilt bar can pivot towards and away from the left front wheel and the right front wheel.

18. A tricycle according to any one of claims 15 to 17, wherein the left link is attached to a left side of the tilt bar and the right link is attached to a right side of the tilt bar.

19. A tricycle according to any preceding claim, further comprising a left suspension fork and a right suspension fork for providing independent suspension in respect of each of the left front wheel and the right front wheel.

20. A tricycle according to any preceding claim, wherein the stabilising apparatus is arranged to raise the left front wheel or right front wheel proportional to a turn of the steering column left or right, respectively.

21. A tricycle according to any preceding claim, wherein the stabilising apparatus is arranged to provide a linear relationship between the turning of the steering column and the raising of an inside wheel when turning the tricycle.

22. A tricycle substantially as described herein with reference to the accompanying drawings.