GB2432199A

GB2432199A - Supplementary gear-change systems for motorcycles

Info

Publication number: GB2432199A
Application number: GB0522813A
Authority: GB
Inventors: Jamie Lee Wilson
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-09
Filing date: 2005-11-09
Publication date: 2007-05-16
Also published as: GB0522813D0

Abstract

A supplementary gear-change system for a motorcycle having a foot-operable gear-change mechanism 14 comprises a manually-operable element 32 for mounting on the handlebars 24 and movable between a rest position and an operated position. The manually-operable element is connected to the gear-change mechanism such that movement by hand of the element from its rest position to its operated position causes movement of the gear-change mechanism in one of its directions to change gear and such that, when the manually-operable element is in its rest position, movement by foot of the gear-change mechanism in the other of its directions does not cause any significant movement of the manually-operable element. The system is particularly useful for motocross motorcycles so that a gear change can be made while the rider's gear-changing foot is not on its footpeg 20.

Description

TITLE

Supplementary gear-change systems for motorcycles

DESCRIPTION

This invention relates to supplementary gear-change systems for motorcycles.

For decades, motorcycles have typically had a foot-operable gear-change mechanism that is movable (for example by a pedal) in a first direction to perform an up-change, in a second direction to perform a down-change and that returns to a rest position after each gear change.

Thus, to change from first to second gear, the pedal is moved from its rest position in the first direction and then allowed to return to its rest position; to change then from second to third gear, the pedal is moved again from its rest position in the first direction and then allowed to return to its rest position; and so on. Conversely, to change from third to second gear, the pedal is moved from its rest position but in the second direction and then allowed to return to its rest position; and so on. In order to select neutral' from first gear, typically the pedal is moved part-way from its rest position in the first direction and then allowed to return to its rest position; and, conversely, in order to select neutral' from second gear, typically the pedal is moved part-way from its rest position in the second direction and then allowed to return to its rest position. Such an arrangement allows gears to be changed sequentially with a single action of the pedal, and also allows neutral to be selected from either first or second gear with a single action of the pedal.

Supplementary gear-change systems for such gear-change mechanisms are also known.

For example many models of Royal Enfield motorcycles are provided with a neutral pedal that can be operated by foot in a single direction when any gear is selected in order to select neutral.

Also, many models of Vincent motorcycles are provided with a gear-indicating pointer on the gearbox cover that pivots to indicate the selected gear against a scale marked 1 -N-2-3-4 on the gearbox cover, but that is sufficiently large and rugged that, in the unlikely event of failure of the gear-change mechanism, the rider can lean down and move the gear-indicating pointer manually in order to change gear.

In the case of riding motorcycles on the road, the conventional wisdom is that the rider should place their feet on the footpegs as soon as the machine starts moving, and keep them there until the machine comes to a halt. However, in the field of solo motocross (or scrambling), a rider will often put their inside foot down when taking a corner in order to steady themself. When coming out of the corner, they may wish to change up a gear. However, if it is left-hand corner and the gear-change pedal is on the left side of the machine, a gear change is not possible until they have lifted their foot from the ground, and doing that too early may interfere with their balance and the way in which they wish to take the corner.

An aim of the present invention, or at least of specific embodiments of it, it to enable a rider of a motorcycle, particularly but not exclusively a motocross motorcycle, having a gear change mechanism as described above to perform at least some gear changes without needing to use the foot pedal. Obviously, providing the Vincent style of supplementary gear-change system would be of no assistance in this scenario because it would require the rider to take one hand off the handlebars and lean down to the gearbox cover, something that would probably result in them falling off their machine. It might be considered that the aim of the invention could be attained by providing a manually operable lever on the handlebars that is connected to the gear-change mechanism so that the mechanism mimics the operation of the lever by the rider's hand. However, with a simple connection between the lever and the gear-change mechanism, the lever would also mimic the operation of the gear-change mechanism by the rider's foot. Therefore, when the rider performed gear-changes by foot, the lever would move. At the least this might be disconcerting to the rider, and at the worst could lead to trapped fingers.

In accordance with a first aspect of the present invention, there is provided a supplementary gear-change system for a motorcycle having a foot-operable gear-change mechanism as described above. The supplementary system comprises a manually-operable element (such as a lever) for mounting on the handlebars of the motorcycle and movable between a rest position and an operated position, and means operably connecting the manually-operable element to the foot-operable gear-change mechanism such that movement by hand of the element from its rest position to its operated position causes movement of the foot-operable gear-change mechanism in one of its directions from its rest position and such that, when the manually-operable element is in its rest position, movement by foot of the gear-change mechanism in the other of its directions from its rest position does not cause any significant movement of the manually-operable element. For example, if the manually-operable element is a lever arranged to be pressed by the rider's thumb in one direction in order to change up a gear, changing down a gear by foot does not result in any significant movement of the lever from its rest position.

Preferably, the connecting means is also operable such that, when the manually-operable element is in its rest position, movement by foot of the gear-change mechanism in said one direction from its rest position does not cause any significant movement of the manually-operable element. As an extension of the above example, changing up a gear by foot also does not result in any significant movement of the lever from its rest position, and thus there is no significant movement at all of the lever from its rest position when gear changes are being made by foot.

In one embodiment, the connecting means comprises: a master cylinder and an associated master piston connected to the manually operable element; a slave cylinder in hydraulic communication with the master cylinder and an associated slave piston connected to the gear-change mechanism; and a hydraulic reservoir in hydraulic communication with the master cylinder only when the manually operable element is at or near its rest position. In this case, the system preferably further includes means (such a spring or a pair of springs) for biasing the slave piston towards a mid position in the slave cylinder. In one version, the slave cylinder may be arranged to be mounted on the handlebars, with the slave piston being arranged to be connected to the gear-change mechanism by a control cable, such as a bowden cable. In another version, the slave cylinder may be arranged to be mounted adjacent the gear-change mechanism, with the master cylinder being connected to the slave cylinder by a hydraulic line.

The supplementary gear-change system may be arranged either for performing an up-change or for performing a down-change. However, in the case of motocross, it is anticipated that most riders will prefer the system to be able to perform an up-change, i.e. said one direction is said first direction for performing an up-change. Alternatively, the system may be developed to include a second manually-operable element for mounting on the handlebars of the motorcycle and movable between a rest position and an operated position, and means operably connecting the second manually-operable element to the foot-operable gear-change mechanism such that movement by hand of the second element from its rest position to its operated position causes movement of the foot-operable gear-change mechanism in said other direction from its rest position and such that, when the second manually-operable element is in its rest position, movement by foot of the gear-change mechanism in said one direction from its rest position does not cause any significant movement of the manually-operable element. Therefore one of the manually-operable elements can be used for up-changes, and the other manually-operable element can be used for down-changes.

In accordance with a second aspect of the invention, there is provided a motorcycle having: a foot-operable gear-change mechanism that is movable in a first direction to perform an up-change, in a second direction to perform a down-change and that returns to a rest position after each gear change, and a supplementary gear-change system according to the first aspect of the invention.

Specific embodiments of the present invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: Figure 1 is a view of an end of a gearbox of a motorcycle that is not fitted with a supplementary gear-change system; Figure 2 is a view of an end of the gearbox fitted with a first embodiment of supplementary gear-change system; Figure 3 is a sectioned view from below and on a larger scale of part of the first embodiment of supplementary gear-change system that is fitted to the handlebars of the motorcycle; Figure 4 is a view of an end of the gearbox fitted with a second embodiment of supplementary gear-change system; Figure 5 is a sectioned view from below and on a larger scale of part of the second embodiment of supplementary gear-change system that is fitted to the handlebars of the motorcycle; and Figure 6 is a sectioned view of another part of the second embodiment of supplementary gear-change system that is fitted to the gearbox.

Referring to Figure 1, an end cover 10 of a motorcycle gearbox 12 has a gear-change shaft projecting therefrom and a gear-change pedal 14 fitted by one end 16 to the gear-change shaft. The other end 18 of the pedal 14 is cranked outwardly so that it can be operated by the rider's foot when their foot is resting on a footpeg 20. The pedal 14 is biased by a gear-change mechanism inside the gearbox 12 to a rest position as shown by full lines in Figure 1 and is movable between upper and lower positions as shown by dot-dash lines in Figure 1. The gear-change mechanism and a gear-selector mechanism inside the gearbox are arranged such that when the pedal 14 is moved fully to its upper position, the next higher gear, if there is one, is selected, and when the pedal 14 is released it returns to its rest position. Conversely, when the pedal 14 is moved fully to its lower position, the next lower gear, if there is one, is selected, and when the pedal 14 is released it returns to its rest position. Furthermore, if first gear is currently selected, when the pedal 14 is then moved half-way towards its upper position, neutral is selected, and when the pedal 14 is released it returns to its rest position. Conversely, if second gear is currently selected, when the pedal 14 is then moved half-way towards its lower position, neutral is selected, and when the pedal 14 is released it returns to its rest position. As described in this paragraph, the operation of the gear-change and gear-selection mechanisms is conventional.

The first embodiment of supplementary gear-change system will now be described with reference to Figures 2 and 3. The system comprises a handlebar assembly 22 that is mounted on the handlebars 24 of the motorcycle, and a bowden cable 26 that extends from the handlebar assembly 22 to a pedal assembly 28 that connects to the conventional gear-change pedal 14 of the gearbox 12.

The handlebar assembly 22 has a body 30 and an operating lever 32 that are mounted beneath the handlebars 24 such that the lever 32 can be depressed by the rider's thumb in the direction 34 without releasing their hand from the handlebars 24. The body 30 provides a master cylinder 36 containing a master piston 38 having suitable seals including a primary seal 61. A master return spring 40 biases the master piston 38 towards the left-hand end of the master cylinder 36. A push-rod 42 extends between the master piston 38 and a crank 44 on the operating lever 32. The operating lever 32 is pivoted to the body 30 about a pin or bolt 46 such that, when the operating lever 32 is depressed in the direction 34, the master piston 38 is moved to the right along the master cylinder 36, and when the operating lever 32 is released, the master piston 38 and operating lever 32 return to the positions shown in Figure 3. The body 30 also provides a stepped slave cylinder 48, having a larger diameter portion 48L and a smaller diameter portion 48S, containing a stepped slave piston 50 having a larger diameter portion 50L and a smaller diameter portion 50S and suitable seals. A pair of slave return springs 52 bias the slave piston 50 to a generally central position along the slave cylinder 48. The bowden cable 26 has an inner 261 that is connected by a nipple at one end to the slave piston 50 and an outer 260 that bears at one end against an end cap 52 of the smaller portion 48S of the slave cylinder.

The master cylinder 36 and master piston 38 together form a generally cylindrical master chamber 54, and the slave cylinder 48 and slave piston 50 together form a generally annular slave chamber 56. The master and slave chambers 54,56 communicate with each other via a port 58 in the body 30 between the two chambers 54,5 6. The master chamber 54 also communicates with a reservoir (shown schematically as 59) for hydraulic liquid (i.e. "brake fluid") via a port 60. For clarity in Figure 3, the port is shown at the top of the drawing, which is to the rear when the body is mounted on the motorcycle handlebars 24. However in practice the port 60 would be arranged to be near the top of the body 30 when the body 30 is mounted on the motorcycle handlebars 24 and the reservoir 59 would be positioned above the body 30. The port 60 is positioned near the rest position of the primary seal 61 of the master piston 38, so that, after the master piston 38 has been moved a short distance from its rest position, communication between the master chamber 54 and the reservoir 59 is blocked. The reservoir 59, master chamber 54 and slave chamber 56 are filled with brake fluid and air is bled from the system via a bleed nipple (not shown). The reservoir 59 may be an independent reservoir, or it may also serve a hydraulic clutch actuation system or hydraulic front brake actuation system of the motorcycle.

Referring to Figure 2, at the other end of the bowden cable 26, the outer 260 bears against an adjuster 62 on a bracket 64 that is secured to the gearbox 12 above the gear-change pedal 14. The inner 261 is connected to a clamp 66 secured to the gear-change pedal 14.

In operation, the gear-change pedal 14 may be used in the normal way to change gear.

When the pedal 14 is moved downwards by foot to change down a gear, it will draw the inner 26! through the outer 260 of the bowden cable 26 so as to move the slave piston 50 to the right. Fluid is therefore transferred from the slave chamber 56 to the master chamber 54. The master piston 38 and operating lever 32 do not move, and fluid is therefore transferred from the master chamber 54 to the reservoir 59. When the gear-change pedal 14 is subsequently released, the slave piston 50 returns, primarily under the action of the return springs 51, to the position shown in Figure 3, and fluid is transferred back from the reservoir 59 to the master chamber 54, and from the master chamber 54 to the slave chamber 56. Conversely, when the pedal 14 is moved upwards by foot to change up a gear, probably the inner 261 of the bowden cable 26 will buckle between the clamp 66 and the adjuster 62, or the ends of the outer 260 of the bowden cable 26 will come away from the adjuster 62 or the end cap 52, and consequently the slave piston 50 will not move. In the event that the slave piston does move, to the left as seen in Figure 3, fluid will be transferred from the master chamber 54 to the slave chamber 56. The master piston 38 and operating lever 32 will not move due to the action of the master return spring 40, and fluid will therefore be transferred from the reservoir 59 to the master chamber 54. When the gear-change pedal 14 is subsequently released, the slave piston 50, if it has moved, will return, under the action of the return springs 51 and the bowden cable 26, to the position shown in Figure 3, and fluid will be transferred back from the slave chamber 56 to the master chamber 54, and from the master chamber 54 to the reservoir 59. It should be noted that, provided that the operating lever 32 is not manually depressed while a gear change is being made by foot, the operating lever 32 will not move while such a gear change is being made.

The function of the operating lever 32 will now be described. The lever can be used only to perform up changes. When the lever 32 is depressed by the rider's thumb in the direction 34, the master piston 38 moves to the right as seen in Figure 3. After a short amount of movement, the primary seal 61 passes beyond the port 60 so as to block communication between the reservoir 59 and the master chamber 54. With continued movement of the lever 32 and piston 38, fluid is forced from the master chamber 54 to the slave chamber 56, and therefore the slave piston 50 moves to the left and draws the inner 26! through the outer 260 of the bowden cable 26. The gear-change pedal 14 is therefore lifted by the inner 261 of the bowden cable 26 so as to change up a gear. When the operating lever 32 is subsequently released by the rider's thumb, the gear-change pedal 14, slave piston 50 and master piston 38 return to their initial rest positions under the action of the springs in the gearbox 12, the slave return springs 51 and the master return spring 40.

The second embodiment of the invention will now be described with reference to Figures 4 to 6. The main differences between the two embodiments are that, in the second embodiment: the slave chamber 56 is provided in a separate body 68 mounted on the bracket 64 on the gearbox 12; accordingly, instead of there being an interconnecting port 58 between the master chamber 54 and the slave chamber 56, a port 58M in the master cylinder 58 communicates with a port 58S in the slave cylinder 48 via a flexible hydraulic hose 70 extending from the handlebars 24 of the motorcycle to its gearbox 12; and the slave piston 50 is connected to the clamp 66 on the gear-change pedal 14 by a straight length of cable 72. The functionalities of the first and second embodiments of the invention are similar.

Various modifications may be made to the embodiments of the invention described above.

For example, the supplementary gear-change system may be arranged to act on the gear-change pedal 14 in the opposite direction to that described above so that the manually-operable lever 32 may be used to perform down-changes, rather than up-changes. A further supplementary gear-change system may be provided, with the two systems being arranged to act oppositely on the gear-change pedal 14 so that the manually-operable lever 32 of one system may be used to perform down-changes, and the manually-operable lever 32 of the other system may be used to perform up-changes. In this case, the two manually-operable levers may be provided adjacent each other for operation by the same hand of the rider, or they may be mounted near opposite ends of the handlebars 24 so that the rider can use one thumb to perform up-changes and their other thumb to perform down-changes.

In the embodiments described above, the manually-operable lever 32, when in its rest position, does not react to any movement of the gear-change pedal 14 because the port 60 between the master chamber 54 and the reservoir 59 is open. Instead of employing a hydro-mechanical arrangement to achieve this, an equivalent, purely mechanical arrangement may be employed in which the manually-operable lever 32 latches with an arrangement that moves with the gear-change pedal 14 only when the manually-operable lever 32 is manually moved from its rest position.

Some motorcycles have an electrically or mechanically operated arrangement that affects the engine operation when a gear change, or a gear change in a particular direction, is being made, for example by retarding the engine. When the supplementary gear-change system is employed, such an arrangement may be arranged to be responsive to the system, for example with a switch that is operated by movement of the slave piston 50.

It should be noted that the embodiments of the invention has been described above purely by way of example and that many modifications and developments may be made thereto within the scope of the present invention.

Claims

CLAIMS

The reference numerals in the claims are not intended to limit the claims.

1. A supplementary gear-change system for a motorcycle having a foot-operable gear-change mechanism (14) that is movable in a first direction to perform an up-change, in a second direction to perform a down-change and that returns to a rest position after each gear change, the supplementary system comprising a manually-operable element (32) for mounting on the handlebars (24) of the motorcycle and movable between a rest position and an operated position, and means operably connecting the manually-operable element to the foot-operable gear-change mechanism such that movement by hand of the element from its rest position to its operated position causes movement of the foot-operable gear-change mechanism in one of its directions from its rest position and such that, when the manually-operable element is in its rest position, movement by foot of the gear-change mechanism in the other of its directions from its rest position does not cause any significant movement of the manually-operable element.

2. A supplementary gear-change system as claimed in claim 1, wherein the connecting means is operable such that, when the manually-operable element is in its rest position, movement by foot of the gear-change mechanism in said one direction from its rest position does not cause any significant movement of the manually-operable element.

3. A supplementary gear-change system as claimed in claim 1 or 2, wherein the connecting means comprises: a master cylinder (36) and an associated master piston (38) connected to the manually operable element; a slave cylinder (48) in hydraulic communication with the master cylinder and an associated slave piston (50) connected to the gear-change mechanism; and a hydraulic reservoir (59) in hydraulic communication with the master cylinder only when the manually operable element is at or near its rest position.

4. A supplementary gear-change system as claimed in claim 3, further including means (51) for biasing the slave piston towards a mid position in the slave cylinder.

5. A supplementary gear-change system as claimed in claim 3 or 4, wherein the slave cylinder is arranged to be mounted on the handlebars, and the slave piston is arranged to be connected to the gear-change mechanism by a control cable (26). (Figures 2& 3) 6. A supplementary gear-change system as claimed in claim 3 or 4, wherein the slave cylinder is arranged to be mounted adjacent the gear-change mechanism, and the master cylinder is connected to the slave cylinder by a hydraulic line (70). (Figures 4 to 6) 7. A supplementary gear-change system as claimed in any preceding claim, wherein said one direction is said first direction for performing an up-change.

8. A supplementary gear-change system as claimed in any preceding claim, further including a second manually-operable element for mounting on the handlebars of the motorcycle and movable between a rest position and an operated position, and means operably connecting the second manually-operable element to the foot-operable gear-change mechanism such that movement by hand of the second element from its rest position to its operated position causes movement of the foot-operable gear-change mechanism in said other direction from its rest position and such that, when the second manually-operable element is in its rest position, movement by foot of the gear-change mechanism in said one direction from its rest position does not cause any significant movement of the manually-operable element.

9. A supplementary gear-change system substantially as described with reference to the drawings.

10. A motorcycle having: a foot-operable gear-change mechanism that is movable in a first direction to perform an up-change, in a second direction to perform a down-change and that returns to a rest position after each gear change, and a supplementary gear-change system as claimed in any preceding claim.