GB2536458A

GB2536458A - A bicycle freewheel selection mechanism

Info

Publication number: GB2536458A
Application number: GB1504524.8A
Authority: GB
Inventors: Evans Clive
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-03-18
Filing date: 2015-03-18
Publication date: 2016-09-21
Anticipated expiration: 2035-03-18
Also published as: GB201504524D0; GB2536458B

Abstract

A bicycle freewheel selection mechanism, enables the bicycle pedals to remain static during gear changes. The bicycle freewheel selection mechanism comprises a rear wheel hub 110 having an internal clutch 150 capable of selectively engaging a rear freewheel when activated; and an activation means for remote location on a bicycle frame arranged so as to permit a user to selectively engage the rear freewheel. The activation may occur by means of a cable, a signaling system or via a conduit, such as hydraulically. In use, the freewheel may be locked when a gear change is made, thereby causing the chain to rotate causing a freewheel device on the cranks to overrun and the gear change to occur.

Description

Intellectual Property Office Application No. GII1504524.8 RTM Date:14 April 2015 The following terms are registered trade marks and should be read as such wherever they occur in this document: Bluetooth (page 8) Intellectual Property Office is an operating name of the Patent Office www.gov.uk /ipo A bicycle freewheel selection mechanism

Field of the Invention

The present invention relates to a bicycle freewheel selection mechanism, more specifically but not exclusively a gear shifting mechanism for a bicycle that enables the bicycle pedals to remain static during gear changes.

Background

Traditional gear shifting mechanisms for bicycles use a chain and derailleur sprocket system to deliver power to the rear wheel. Derailleur gears are a variable ratio transmission system consisting of a chain, multiple sprockets of different sizes; and a mechanism to move the chain from one sprocket to another.

In order to change gears the derailleur moves the chain from one sprocket to 20 another.

Modern front and rear derailleurs typically consist of a moveable chain-guide that is operated remotely by a cable attached to a gear shifter mounted on the down tube, handlebar stem, or handlebar. Mien a rider operates the lever while pedalling the change in cable tension moves the chain-guide from side to side thereby "derailing" the chain onto different sprockets.

Most current systems employ a free wheel device within the rear sprocket set that allows the rider to stop pedalling, leaving their feet at rest whilst the bicycle is still in motion. The freewheel allows the rear wheel to continue to rotate whilst leaving the rear sprocket set, chain and front chain wheel stationary. On resuming pedalling the drivetrain overrides the freewheel and power is delivered to the rear wheel provided the drivetrain is rotating at a faster speed than the revolutions per minute dictated by the ground speed.

Current systems employing a chain, sprocket and derailleur require the 5 drive-train to be in motion before a change of ratio (gear) can take place. Due to the current arrangement of the drivetrain components riders must be pedalling before they can effect a change of ratio (gear). This is achieved by either being on the bicycle in motion and pedalling or by lifting the rear of the bicycle and driving a peddle around with one foot whilst operating the gear 10 shift lever on the handle bars.

When riding on rough downhill terrain situations arise where riders stand on the pedals for balance, if the terrain changes quickly a rider can find themselves in the wrong gear for the approaching ground but also unable to pedal due to balancing on their pedals; this can therefore delay or make difficult a gear change and result in a loss of speed or the need to dismount Also many off road bicycles have "drop seat posts and if this is in the lower position sitting to pedal to change gear is not easy as the rider is not in the 20 preferred cycling position.

Furthermore lifting the rear wheel to effect a change of ratio is an awkward task and may not always be practical.

Prior Art

Shirnano (RIM) introduced its Front Freewheel System (FES) that placed a freewheel between the pedal cranks and the front chainrings. The "freewheeling" mechanism was built into the crankset bottom bracket, but.for safety reasons, the rear cogs were not just fixed to the wheel. The rear freewheel had higher friction than the front so that the spinning of the wheel will drive the freewheel and chain when coasting enabling the rider to shift gears with no pedal strokes.

In contrast the present invention provides a user operated or automatic 5 system to select between front or rear free wheel.

Summary of the Inve.ntion

According to the present invention there is provided bicycle freewheel selection mechanism comprising: a rear wheel hub having an internal clutch capable of selectively locking a rear freewheel when activated; and an activation means for remote location on a bicycle frame arranged so as to permit a user to selectively lock the rear freewheel.

In this way the internal clutch is capable of selectively overriding the rear freewheel and so locking the rear gear cassette of a bicycle with rotation of the wheel causing the whole transmission system to be driven by rotation of the rear wheel.

The activation means are arranged to be with reach of a user whilst riding the bicycle so as to permit the user to selectively lock the rear freewheel. In some embodiments selectively locking the rear freewheel may be integrated with a gear shifter so that locking occurs automatically with a gear change.

In preferred embodiments a front freewheel is provided on a bicycle crank so as to have a front and rear freewheel wherein the rear free wheel is selectively locked or engaged by a user.

Preferably a front freewheel is fitted between the front pedal crank arms and the front chain ring. In this way a user may cease pedalling and thereby the crank arms are stationary even when the rear freewheel is locked.

Whilst the rear freewheel is active (not locked) the inherent mechanical resistance of a bicycle drivetrain stops the front freewheel from being active and therefore the rear freewheel resumes normal function, i.e. movement in response to turning of the crank arms by pedalling.

In this way the rear freewheel can he locked so as to permit rotation of the bicycle drivetrain if the wheels are turning, without the requirement of turning of the crank arms. Therefore a rider does not need to pedal in order to drive the chain to permit a gear change but can instead lock the rear freewheel to activate the chain (provided the wheels are turning) so as to achieve a successful gear change without having the drive the chain by pedaiiing. Therefore a gear change can be achieved without pedalling as long as the wheels are turning, for example if roiling downhill or pushing the bicycle along.

Advantageously if a rider is for example riding downhill on rough terrain it is possible to change gears to pre-empt forth coming changes in terrain, such as an uphill section, without having to pedal. Therefore a rider is able to maintain optimal balance and stability as they do not have to pedal and can remain in a fixed pedal position. However the rider can still change gear, therefore preparing for changes in terrain and saving them the time of having to work through the gears after the terrain has changed and removing the risk of pedalling during technical downhill sections in attempt to change gear.

Advantageously by having a front freewheel and rear freewheel the drivetrain 25 can remain stationary whilst the wheels are turning so for example if the rider is cycling downhill at speed the drivetrain can be stationary and there is no risk of the chain catching the user's leg and/or clothing. This reduces the Advantageously as the locking of the rear freewheel is selective wear and tear 30 of the freewheel locking mechanism is reduced and standard bicycle freewheel operation is maintained by the rear hub unless activated.

A user can also carry out standard gear changes made whitest driving the chain through pedalling.

The rear hub includes an axle for receiving a spindle such as a quick release 5 wheel shaft. The axle is typically clamped to the bike frame and is the only non-rotating component of the hub. All other rear huh components rotate around the axle.

Preferably the axle has at least one bearing that enables the rear hub to 10 rotate about the axle. Size and type of bearing may be varied depending upon the user, bicycle, and/or use of the bicycle.

In some embodiments more than one bearing may be provided in order to withstand greater forces.

The rear wheel hub includes an internal clutch moveable along an axis so as to engage with the rear freewheel in order to permit movement of the chain in response to turning of the bicycle wheels. The internal clutch is arranged within the rear hub body.

Preferably the clutch comprises a clutch plate to enaage the freewheel. In this way if an item such as a piece of clothing or a plant was to become caught in the drivetrain the freewheel can continue to rotate on the wheel and does not drag the caught item into the drivetrain. Advantageously this reduces the risk of accidents or injury to the rider.

Preferably the rear wheel hub includes at least one actuator arranged within the rear hub body that is moveable along an axis in response to a force. Typically the actuator may comprise an actuator rod or rods. Ideally the axis in which the actuator moves corresponds to axis of the wheel spindle. The wheel spindle may comprise a quick release wheel shaft.

In some preferred embodiments the actuator may corn.. prise one or more actuator rods arranged parallel to the hub body and wheel spindle.

In other embodiments the actuator may comprise a collar or a split collar 5 arranged concentrically about the spindle.

Movement of the actuator results in an applied force through the rods to the clutch or clutch plate that then engages with the rear freewheel so as to lock the freewheel into unified movement with rotation of the rear wheel. In this way when the actuator or actuator rods are engaged with the dutch plate the rear freewheel is locked.

Preferably the rear hub includes a return mechanism so as to return the actuator(s) to a first position. In this way the actuator is returned from a second position wherein the actuator is applying a force to the thereby putting the actuator in contact with the clutch plate, to the first, at rest position, wherein the actuator is not applying force to the clutch plate and therefore the actuator is not in contact with the clutch plate.

Typically the return mechanism may comprise at least one return spring. Ideally the return springs may be mounted on a housing that houses the actuator rods.

The activations means are controllable by a user so as to selectively lock the 25 rear freewheel by means of the clutch within the rear hub Ideally the activation means are located remotely on the bicycle so as to be easily reached by a user whilst cycling.

Preferably the activation means are arranged on the handlebars so that a user can activate the activation means whilst maintaining contact with the handlebars. For example the activation means may be triggered by a user's fingers whilst the user's palms remain on the handlebars.

In some embodiments the activation means may he remote of the bicycle, for example to be held and controlled by a third party. In this way selection or engagement of the rear freewheel can be remotely controlled.

Preferably the activation means includes or comprises a lever or button for use by a user that when activated enables movement of the actuator rod(s) along the axis in the rear hub.

Typically the activation means provides or generates a force that is transmitted to the rear hub so as to move the actuator rods along the axis to engage the actuator rods with the clutch plate and permit locking of the rear freewheel.

In some embodiments the activation means may be connected to the rear hub by a hollow tube, line or conduit containing fluid so as to enable hydraulic or pneumatic fluid pressure to be used to initiate movement of the actuator(s) to engage the clutch.

In other embodiments the activation means may be connected to the rear hub by means of a cable wherein the activation means causes movement of the cable and thereby the actuator(s) so as to engage the clutch plate.

In another embodiment the activation means may he automatic wherein activating the activation means triggers a signal to be sent to the rear hub and the signal triggers a force to move the actuator(s). For example the rear hub may include an electro-magnetic coil that generates a force to move the actuator on receipt of an electronic signal.

In an alternative embodiment an electronic switch may be provided. For example a switch may be integrated in a bicycle shifter mechanism wherein each click of the shifter to move up or down through the gears generates a signal that can be used to trigger activation of the rear hub.

The automatic system may include a servo-mechanism or servo to b g about movement of the actuator rods.

In an alternative embodiment the rear hub may be activated by a magnetic switch means, such as a solenoid. Typically a battery may he provided mounted to or integrated with the frame to provide an energy source for automatic activation means.

In yet further embodiments a wireless signal such as Bluetooth (RIM) or Radio Frequency (RF) may be used to transmit a signal from the activation means to the rear hub. In this way there is no requirement for a conduit and the frame is not required to be adapted to support the conduit.

In some embodiments the activation means may be integrated with a gear shifter so that the rear freewheel locking mechanism is activated seamlessly and without the riders consideration ust prior to the gear change providing a sequential set of events.

In this way the present invention would offer maximum benefit to the rider as a rider could effect a change of gear at any time providing the bike is in motion without any understanding of the function of the system, whether peddling or not. For example this may be particularly advantageous for novice riders that are not used to co-ordinating gear changes with terrain.

In some further embodiments movement of the gear shifter components may operate a switch that activates the freewheel selection mechanism, therefore providing a simple means of automatic activation using standard parts already provided on a bicycle. For example the gear shifter could be modified to include a switch that generates a signal when changing up or down the gears. The signal serves to activate the rear hub so as to bring about movement of the actuator rods along the axis to engage the clutch plate with the freewheel.

Advantageously this permits the user to use one action to bring about sequential activation of the freewheel selection mechanism and a gear change.

Advantageously the freewheel selection mechanism may be readily retrofitted to a bicycle. Typically this may involve fitting a new rear wheel having the rear hub described above and fitting an activation means.

Furthermore it may be possible to change the activation means so that a user may select the activation means they wish to use arid/or 'upgrade' or 'downgrade the activation means for user preference or based on bicycle use or type. For example a particular combination of the freewheel selection mechanism: may be fitted for racing; such as a lighter weight assembly, or a heavy duty assembly for endurance mountain biking where forces applied by the user may be greater and prolonged.

Preferred embodiments of the invention will now be described, by way of example and with reference to the Figures in which:

Brief Description of Figures

Figure 1 shows a cross section of a rear hub assembly; Figure 2 shows an exploded view of the rear hub assembly shown in Figure 1; Figure 3A shows an end view of the hub body end that receives the clutch plate with three notches; Figure 3B shows an end view of the hub body with the clutch plate in position; Figure 4A shows an example of the face of a clutch plate that interfaces the hub body; Figure 4B shows an example of the face of a clutch plate that interfaces the freewheel; Figure 5 shows an overview of a bicycle freewheel selection mechanism; and Figure 6 shows a drivetrain.

petailedDescilatign of; Fie< ures Figure 1 shows a cross section of a rear hub assembly 100 or rear hub. The rear hub 100 (or rear hub assembly) has a generally cylindrical shaped hub body 110 that houses components of a bicycle freewheel selection 15 mechanism as shown in Figures 1 to 4.

Running centrally through the rear hub is a hole 120 for receiving a spindle such as a quick release clamping shaft (not shown). The hole 120 is defined by an axle 130.

The axle 130 is damped to the bike frame arid is the only non--rotating component of the hub. All other hub components rotate around the axle 130 The axle 130 has bearings 115 mounted on it that enable the rear hub 110 to rotate about the axle 130.

The hub body 110 houses hub bearings 115 as shown in Figures 1 and 2.

The rear hub 100 shown in Figures 1 and 2 includes four actuator rods 140a; 140b, 140c and 140d only two of which are shown. Actuator rods 140 are 30 moveable in the same direction along axis X-X' in apertures in the hub body 110.

The huh body 110 includes four apertures 112 each receives an actuator rod 140a, 140b etc. The actuator rods 140 are connected at their proximal ends 141 to a housing 5 145. The housing 145 also houses a bearing 146 that ensures hydraulic cylinder 160 can remain static whilst the hub body 110 rotates.

R is appreciated that the number of actuator roads 140 may be varied in different embodiments. A greater number of actuator rods 140 provides a 10 more robust engagement with a dutch plate 150 so that the load is able to be spread across a greater surface area, thereby reducing the risk of failure.

The actuators rods 140 are moved from a first position, in which their distal ends 142 are not in contact with the clutch plate 150 (applying no load), to a 15 second position wherein their distal ends 142 are in contact with the clutch plate 150 applying a force so that a rear freewheel 170 is engaged (locked).

In Figure 2 the dutch plate 150 is shown formed from two parts, a support plate 150A and the friction plate 1508. It is appreciated that the clutch plate 20 150 may be provided as a single part.

Referring to Figures 3A, 3B, 4A and 48 clutch plate 150 is annular having drive lugs 151 dimensioned to be aligned with actuator rod's 140..the Inner machined diameter 110A of the huh body 110 is machined to include notches 25 111 that receive the drive lugs 151.

When the actuator rods 140 apply a force to the clutch plate this plate frictionally engages with the freewheel 170 The notches 111 and drive lugs 151 of the clutch plate 150 then engage to prevent rotation of the rear huh independently of the clutch plate 150 and freewheel 170. Therefore when the clutch plate 150 (due to the force applied by rods 140) is frictionally engaged with the freewheel 170 the hub body 110 and freewheel 170 rotate together in unison as the independent rotation of the clutch plate 150 with respect to the hub body 110 in prevented by drive lugs 151.

The rear hub assembly 100 includes a hydraulic cylinder 160 that transmits a 5 force, applied by the cyclist on an activation means (not shown) to the housing 145 so as to move the actuator rods 140 through the apertures 112 in the hub body 110 along the axis XX' to be in contact with the clutch plate 150.

The hydraulic cylinder shown in Figure 2 includes a body 161, a piston 162, 10 an outer piston seal 163 and an inner piston seal 164.

The hydraulic cylinder 160 is moved by compression of hydraulic fluid in a conduit or line 210 (shown in Figure 5). Activation of the compression is by the activation means 200 (shown in Figure 5) that is connected to the 15 hydraulic cylinder 160 by the conduit or line 210.

The activation means 200 is mounted remote to the rear hub 100, typically being mounted on the handlebars 220 or stem of a bicycle. When the activation means 200 is triggered hydraulic fluid (not shown) is forced down the conduit or line 210 that in turn provides a force to move the hydraulic cylinder 160 along the axis X-X' thereby forcing movement of the actuator rods 140 towards the clutch plate 150.

As the distal ends 142 of the actuator rods 140 connect with the clutch plate 25 150 the rear freewheel 170 is locked to hub 110 and so to the rear wheel. At this point the whole drivetrain 400 (shown in Figure 6) that includes a front mechanism 300A, a rear mechanism 300E3 linked by a chain 400A.

The drivetrain 400 is driven by the motion of the rear wheel and the front 30 freewheel takes over so as to permit gear changing without requirement for a user to turn the crank by pedalling.

Under normal riding conditions (rear freewheel active and not locked) the drivetrain 400 will not be driven by the rotation of the rear wheel, the natural friction within the drivetrain 400 will mean the rear freewheel will be active under these conditions as on a conventional bicycle.

As shown in Figures 1 and 2 the housing 145 includes return springs 180 that serve to return the housing 141 and thereby the actuator rods 140 from the second position to the first position.

Return springs 180 are coiled springs that are located within the same face of the housing 145 as the actuator rods 140. As the housing 145 is moved along the axis X-X by the hydraulic cylinder 160 the return springs 180 become compressed and when the hydraulic cylinder 160 is released the return springs 180 are also released and therefore return the housing 141 to the first position.

In Figures 1 and 2 the rear hub 100 is shown including a spacer 190. The spacer bridges the gap between the hub bearing 115 and the bike frame rear forks this is a non--rotating part and forrns part of the axle assembly 130. In some other embodiments a modified freewheel 170 may be provided to remove the requirement for a separate spacer 190.

Figure 5 shows an overview of the bicycle rear freewheel selection mechanism wherein the activation means 200 is provided on handlebars 220.

A user can activate the activation means 200 whilst cycling so as to cause movement of the actuator rods 140 by means of the hydraulic cylinder 160 that is forced along the axis X-X, so as to engage distal ends of the actuator rods 142 with the clutch plate 150 in order to engage/lock the rear freewheel 170.

In this way the drivetrain 400 is driven by the rear wheel rotation without requirement of the user to pedal the crank 500.

Figure 6 shows an overview of a drivetrain 400 having a front mechanism 300A that includes a front freewheel 300G, a rear mechanism 300B and a chain 400A. The drivetrain 400 can be driven by the crank arms 500 and/or by turning of the wheels when the rear freewheel is locked.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of invention Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described; and accordingly, suitable modifications and equivalents are considered to fall within the scope of the claims appended hereto.

Claims

Claims 1. A bicycle freewheel selection mechanism comprising: a rear wheel hub having an internal clutch capable of selectively locking a rear freewheel when activated: and an activation means for remote location on a bicycle frame arranged so as to permit a user to selectively engage the rear fre,ewheel.
2. A bicycle freewheel selection mechanism according to claim 1 wherein when the rear freewheel is engaged, a gear changer enables the user to change gear without pedalling.
3. A bicycle freewheel selection mechanism according to claim 1 or 2 wherein the activation means is connected to the rear hub by a conduit.
4. A bicycle freewheel selection mechanism according to any preceding claim wherein the activation means is connected to the rear hub by means of a cable 5. A bicycle freewheel selection mechanism according to any preceding claim wherein the activation means sends a signal to the rear hub so as to engage the rear free wheel.6. A bicycle freewheel selection mechanism according to claim 5 including a battery.7. A bicycle freewheel selection mechanism according to any preceding claim wherein the activation means is located on a handlebar.8. A bicycle freewheel selection mechanism according to claims 1 to 6 wherein the activation means is located on a stern or down tube.9. A bicycle freewheel selection mechanism according to any preced claim wherein the activation means are automatic.10.A bicycle freewheel selection means wherein the activation is integrated with a gear shifter so that the freewheel selection mechanism is activated prior to a gear change providing a sequential set of events.11.A rear hub according to any of claims.1 to 10.12. A ar wheel including a hub with a freewheel selection mechanism according to any of claims 1 to 10.13. A bicycle including the rear wheel according to 11.14. A bicycle freewheel selection mechanism as substantially herein described with reference to the figures.Amendments to the claims have been filed as follows: Claims 1. A bicycle freewheel selection mechanism for use with a bicycle having a front freewheel system comprises: a rear wheel hub having an internal dutch capable of selectively locking a rear freewheel, so that when activated the rear freewheel and a rear gear cassette rotate with the rear wheel, thereby causing a bicycle transmission system to be driven by rotation of the rear wheel; an activation means is located on a bicycle frame remote from the rear wheel hub, which activation means in use engages the internal clutch so locking the rear freewheel, thereby enabling a user to change gear without pedalling. (r)3. A bicycle freewheel selection mechanism according to claim 1 or 2 wherein the activation means is connected to the internal clutch in theCDrear hub by means of a cable.0 4. A bicycle freewheel selection mechanism according to any preceding claim wherein the activation means sends a signal to the rear hub so as to engage the rear free wheel.
5. A bicycle freewheel selection mechanism according to claim 4 including a battery.
6. A bicycle freewheel selection mechanism according to any preceding claim wherein the activation means is located on a handlebar.
7. A bicycle freewheel selection mechanism according to any preceding claim wherein the activation means is located on a stem or down tube.2. A bicycle freewheel selection mechanism according to claim 1 wherein the activation means is connected to the internal clutch in the rear hub by a conduit.
8. A bicycle freewheel selection mechanism according to any preceding claim wherein selectively locking the rear freewheel is integrated with a gear shifter so that locking occurs automatically with a gear change.
9. A bicycle freewheel selection means according to claim 8 wherein the activation means is integrated with a gear shifter so that the freewheel selection mechanism is activated prior to a gear change providing a sequential set of events.
10.A bicycle freewheel selection mechanism according to any preceding claim wherein the activation means triggers a signal to be sent to the rear hub and the signal triggers a force to move an actuator.
11,A bicycle freewheel selection mechanism according to any preceding claim wherein a switch is integrated in a bicycle gear shifter mechanism so that gear shifter components operate a switch that activates the freewheel selection mechanism.
12.A bicycle freewheel selection mechanism according to claim 11CDwherein each click of the gear shifter to move up or down through the cr) gears generates a signal that can be used to trigger activation of the rear hub.
13.A rear wheel including a hub with a bicycle freewheel selection mechanism according to any preceding claim.
14.A bicycle including the rear wheel according to claim 13.
15.A bicycle freewheel selection mechanism as substantially herein described with reference to the figures.