Bicycle rear derailleur selection system

Abstract

A transmission gear selection system for a bicycle or the like, comprising: a central support shaft (2) of a bicycle wheel, the central support shaft (2) being connected to a pair of fork-shaped members (F1, F2) of the bicycle; a gear set (4) being rotatably and axially slidably connected to the central support shaft (2); a moving device (6) of the gear set (4) on the central support shaft (2); wherein the central support shaft (2) comprises a first end (7) and a second end (8), the first end (7 ) is connected to the first fork-shaped member (F1) in a detachable manner, the second end portion (8) is axially slidably connected to the second fork-shaped member (F2), and the central support shaft (2) can slide relative to the fork-shaped members (F1, F2) between a working position and a disassembly position, in which the central support shaft (2) is inserted between the fork-shaped members (F1, F2); in the disassembly position, the central support shaft (2) is at least partially pulled out of the fork-shaped members (F1, F2) through the second fork-shaped member (F2) to disassemble / assemble the wheel.

Description

Technical Field

[0001] The present invention relates to a transmission gear selection system for a bicycle or the like. Background Art

[0002] With regard to bicycles, from leisure bicycles to racing bicycles and so-called mountain bicycles, the use of adapted gears to allow the selection of different transmission gears in order to facilitate pedaling and to adapt to the different characteristics of the road is well known and common.

[0003] In particular, the most common type of bicycle gears are the so-called derailleur gears.

[0004] The derailleur gears consist of a series of sprockets of different and predefined sizes placed side by side, and a mechanism controlled by the rider, called a derailleur, adapted to shift the chain from one gear to another and to keep the chain under tension.

[0005] Generally, in leisure bicycles there is only one set of sprockets, the so-called cogs, integrally mounted on the hub of the rear wheel and only one rear derailleur, whereas racing bicycles or mountain bikes may have more crown wheels and a second front derailleur arranged side by side at the pedal group.

[0006] Specifically, mountain bikes typically have up to ten sprockets on the rear wheel and up to three crown wheels on the pedal set, for a total of thirty possible gears, while racing bikes typically have up to eleven gears on the rear wheel and up to two crown wheels on the pedal set, for a total of twenty possible gears.

[0007] The gearbox is controlled by one or more special levers, by which the chain can be operated to move from one gear to another and / or from one crown wheel to another.

[0008] For example, one of the most common solutions is to use a controller provided with a pair of levers mounted on the handlebars, wherein a first larger lever when operated stretches the gear cable by moving the derailleur and brings the chain to a larger gear.

[0009] On the other hand, operation of the second lever causes the cable to be released by moving the derailleur and brings the chain to a smaller cog.

[0010] However, gears of known type do have some disadvantages.

[0011] In particular, a first disadvantage is that the continuous movement of the chain on the gears and crown wheel and the fact that the chain in many cases runs in an offset position, whereby the chain is inclined relative to the teeth of the gears and crown wheel, leads to severe wear of the chain itself.

[0012] As a result, over time the chain can function less and less effectively or even break, with obvious risks for the rider, necessitating constant maintenance and inspection as well as regular replacement operations.

[0013] Furthermore, another disadvantage is that, since the chain runs in an inclined position relative to the teeth of the gears and crown wheel, the risk of the chain falling increases significantly, with all the inconveniences and risks that this entails.

[0014] Another disadvantage is that, due to running in an inclined position relative to the teeth of the gear and crown wheel, the force transmitted to the chain by the action on the pedal group includes a transverse component, so that not all the energy applied to the pedal group is transmitted to the gear.

[0015] Likewise, a disadvantage is that the number of maximum possible gears is limited by the maximum size of the gear set at the rear wheel hub on the one hand and by the maximum inclination and travel of the chain relative to the teeth on the other hand, which cannot be exaggerated.

[0016] Last but not least, in order to overcome all the above problems, the chain itself as well as the teeth and structure of the gears and crown wheels must be machined, shaped and dimensioned in such a way as to facilitate the engagement of the chain on the teeth at any possible inclination, as well as to reduce the overall weight of the gear set.

[0017] Therefore, it is necessary to make the chain and the gear have suitable shapes and increasingly smaller thicknesses, which significantly increases the overall cost of gear manufacturing.

[0018] It should also be noted that smaller and thinner gears also mean smaller and thinner chains, and therefore, more fragile chains that break more easily.

[0019] In order to partially overcome these disadvantages, the solution described in WO2019 / 077526A1 is known. Specifically, the document describes a transmission gear selection system, which includes a gear set axially slidingly connected to the hub of the bicycle wheel. In particular, the gear set is provided with a plurality of gears of different sizes, and the plurality of gears of different sizes are arranged side by side with each other from the smallest gear to the largest gear.

[0020] The selection system comprises a moving device for moving the gear set on the hub between a first extreme position, wherein in the first extreme position the smallest gear is located at the drive chain of the bicycle, and a second extreme position, wherein in the second extreme position the largest gear is located at a point of the chain.

[0021] In this way, the derailleur gear is adjusted by moving the cogs rather than the chain, so that the chain always remains axial and is not subjected to excessive stress.

[0022] The aforementioned additional selector system is convenient, allowing the wheel to be removed independently of the gear set.

[0023] Contrary to known solutions, the gear set is in fact not connected to the wheel but to the bicycle frame.

[0024] For this purpose, the selection system is provided with a quick removal / assembly device of the wheels independent of the gear set.

[0025] In particular, the disassembly / assembly device is connected to the bicycle frame and includes a rotation device for rotating one of the forks, allowing it to be moved away from the wheel hub.

[0026] In other words, the forks are moved away from each other to facilitate wheel changing.

[0027] However, this solution implies intervention in the bicycle frame, which complicates the construction and manufacture of the bicycle itself.

[0028] Therefore, it is clear that this last solution can be improved. Summary of the invention

[0029] The main purpose of the present invention is to devise a system for selecting the gears of a transmission in a bicycle or the like which allows to keep the chain straight and axial during use, while allowing a simple and quick change of wheels.

[0030] Another object of the present invention is to devise a transmission gear selection system in a bicycle or the like which allows an easy change of wheels without requiring manipulation of the bicycle frame.

[0031] Another object of the present invention is to devise a system for selecting transmission gears in a bicycle or the like which will overcome the above-mentioned drawbacks of the prior art within the scope of a simple, rational, easy, effectively used and inexpensive solution.

[0032] The above-mentioned object is achieved by the transmission gear selection system in a bicycle or the like of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features and advantages of the invention will become more apparent from the description of a preferred but not exclusive embodiment of a system for selecting a gearshift position in a bicycle or the like, which is illustrated by way of indicative but not limiting example in the accompanying table of the drawings, in which:

[0034] Figure 1 is an axonometric diagram of a selection system for a bicycle transmission gear according to the present invention;

[0035] Figure 2-4 are cross-sectional views of a selection system according to the present invention in different operating configurations. DETAILED DESCRIPTION

[0036] With particular reference to the drawings, reference numeral 1 generally designates a transmission gear selection system in a bicycle or the like.

[0037] In the context of this disclosure, "bicycle" refers to any type of bicycle, from recreational bicycles to racing bicycles and mountain bikes.

[0038] The selection system 1 comprises a central support axle 2 of at least one wheel R of a bicycle B, to which the at least one central support axle 2 is connected a pair of forks F1 , F2 of the bicycle B.

[0039] In the context of this disclosure, the term "fork" refers to a pair of extensions of a bicycle frame, located on the right and left sides of the bicycle, for supporting the wheels.

[0040] The selection system 1 further comprises at least one hub member 3 which is rotatably and detachably connected to the central support shaft 2 and which is arranged at the first fork F1 of the bicycle B.

[0041] The central support shaft 2 and the hub member 3 thus define a hub of a wheel R of the bicycle B, by which the wheel R can rotate.

[0042] In particular, the selection system 1 is intended to be applied to a rear wheel R of a bicycle B.

[0043] In more detail, the central support shaft 2 is connected to the forks F1 , F2 , while the hub member 3 is connected to the spokes of the wheel R.

[0044] The selection system 1 further comprises at least one gear set 4 which is rotatably and axially slidably connected to the central support shaft 2 .

[0045] The gear set 4 is provided with a plurality of gears 5 of different sizes, and the plurality of gears 5 of different sizes are arranged side by side from the smallest gear 5a to the largest gear 5b.

[0046] In particular, the gear set 4 is connected to the central support shaft 2, wherein the smallest gear 5a faces the hub member 3 and the largest gear 5b faces the second fork F2.

[0047] The selection system 1 also includes a moving device 6 of the gear set 4, which is between a first end position and a second end position on the central support shaft 2. In the first end position, the moving device 6 is arranged at the second fork F2 of the bicycle B and the smallest gear 5a is located at the drive chain C of the bicycle B; in the second end position, the moving device 6 is moved away from the second fork F2 and the largest gear 5b is located at the chain C.

[0048] Essentially, the selection system 1 allows the transmission gear to be changed by moving the gear set 4 relative to the central support shaft 2 and keeping the chain C straight.

[0049] According to the present invention, the central support shaft 2 comprises a first end 7 and a second end 8, wherein the first end 7 is detachably connected to the first fork-shaped member F1, and the second end 8 is axially slidably connected to the second fork-shaped member F2.

[0050] The central support shaft 2 can slide relative to the forks F1 and F2 between a working position and a disassembly position. In the working position, the central support shaft 2 is inserted between the forks F1 and F2, and the first end 7 is connected to the first fork F1; in the disassembly position, the central support shaft 2 is at least partially pulled out of the forks F1 and F2 through the second fork F2, and the first end 7 is moved away from the first fork F1 to disassemble / assemble the wheel R.

[0051] In the removal position, the center support shaft 2 continues to support the gear set 4, but the center support shaft 2 is pulled out of the hub member 3 to allow the wheel R to be removed.

[0052] In fact, the hub member 3 defines an operating seat 9, into which, in the working position, the central support shaft 2 is inserted. The central support shaft 2 is movable and slidable relative to the operating seat 9 between the working position and the removal position.

[0053] Advantageously, the central support shaft 2 includes at least a first tubular member 10 and a second tubular member 11, the first tubular member 10 is connected to the forks F1 and F2, the second tubular member 11 is connected to the outside of the first tubular member 10, the second tubular member 11 and the first tubular member 10 are locked together and slide, the second tubular member 11 can rotate and move relative to the first tubular member 10, and supports the gear set 4.

[0054] The first tubular member 10 and the second tubular member 11 are substantially coaxial, and the second tubular member 11 is fitted on the first tubular member 10 .

[0055] In the disassembly position, both the first tubular member 10 and the second tubular member 11 are pulled out of the forks F1 , F2 by the second fork F2 , and the first tubular member 10 and the second tubular member 11 are locked to each other.

[0056] In the working position, at the other end, the first tubular member 10 remains substantially stationary, while the second tubular member 11 is set in rotation by the gear set 4 .

[0057] In fact, the gear set 4 is locked in connection with the second tubular member 11 in rotation and axial sliding.

[0058] In other words, the rotation of the gear set 4 via the chain C causes a synchronous rotation of the second tubular member 11 , which transmits the motion to the hub member 3 and thus to the wheel R.

[0059] In particular, the central support shaft 2 is connected to the operating seat 9 of the hub member 3 through the second tubular member 11 .

[0060] The hub member 3 is locked in rotation with the second tubular member 11 in order to transmit the motion to the wheel R, and furthermore, it slides axially relative to the second tubular member 11 in order to be removed during a wheel R replacement operation.

[0061] According to a preferred embodiment, as shown in the figures, the operating seat 9 is formed inside at least a first portion of the hub member 3, arranged at the first fork F1.

[0062] In particular, according to the preferred embodiment, the portion of the hub member 3 where the operating seat 9 is provided includes a first flange 12 for fixing the spokes of the wheel R.

[0063] The second flange 13 is formed at a second portion of the hub member 3 .

[0064] The hub member 3 comprises a housing 14 adapted to partially accommodate the gear set 4 when the gear set 4 is moved from the first end position to the second end position.

[0065] The housing 14 is defined at the second portion of the hub member 3 .

[0066] The housing 14 is adapted to gradually accommodate the gear 5 during the movement of the gear set 4. Figure 3 )

[0067] Advantageously, still according to the preferred embodiment shown in the figures, the housing 14 has a substantially hollow frustoconical configuration, the cross-sectional area of ​​which increases away from the first fork F1 .

[0068] In other words, the configuration of the housing 14 corresponds substantially to that of the gear set 4 , which is accommodated to the dimensions of the housing 14 and is almost completely inside the housing 14 when the gear set 4 is in the second end position.

[0069] According to a possible variant, the wall of the housing 14 is provided with a plurality of openings suitable for reducing its overall weight.

[0070] Conveniently, the first tubular member 10 comprises a first extreme portion 15 connected to the first fork-shaped member F1 and a second extreme portion 16, wherein the first extreme portion 15 is connected to the first fork-shaped member F1 and the second extreme portion 16 is movably and slidably connected to the second fork-shaped member F2.

[0071] Conveniently, the selection system 1 comprises at least one retaining member 17 of the first end portion 15 relative to the first fork F1 .

[0072] The retaining member 17 provides for firmly fixing the selector system 1 on the frame of the bicycle B and prevents possible axial movement of the central support shaft 2 during use of the bicycle B.

[0073] In the embodiment shown in the figures, the retaining member 17 includes a threaded portion 18 connected to a corresponding threaded hole 19 defined at the first end portion 15 of the first tubular member 10 .

[0074] However, it cannot be excluded that the retaining member 17 is of a different type and can be connected to the first end portion 15 in another way.

[0075] Advantageously, the selection system 1 comprises at least one locking member 20 associated with the second end 8 and suitable for operating with the second fork F2 so as to keep the central support shaft 2 in the disassembled position.

[0076] The lever-type locking member 20 is rotationally movable relative to the second end portion 16. In the working position, the locking member 20 is transverse to the central support shaft 2 and is arranged in contact with the second fork F2 so as not to hinder the user of the bicycle B during use. In the removal position, the locking member 20 is rotated and arranged substantially parallel to the central support shaft 2. In such a position, the locking member 20 abuts against the second fork F2 and prevents the central support shaft 2 from being accidentally assembled between the two forks F1, F2 during the replacement operation of the wheel R.

[0077] However, it cannot be excluded that the locking member 20 is of a different type.

[0078] As mentioned above, in the working position, the gear set 4 slides relative to the central support shaft 2 to allow the transmission gear to be changed.

[0079] The moving device 6 includes an elastic device 21, which is used to push the gear set 4. The elastic device 21 is connected to the outside of the first tubular member 10. The elastic device 21 is operably inserted between the gear set 4 and the first end 7 and is suitable for applying pressure to the gear set 4 toward the first end position.

[0080] Basically, the elastic means 21 , for example of the spring type, comprises an end locked with the first end portion 15 and an opposite end connected to the gear set 4 .

[0081] More specifically, the gear set 4 includes a bushing member 25 connected to the gear 5 and inserted between the first tubular member 10 and the second tubular member 11 , adapted to allow the gear set 4 to slide on the central support shaft 2 .

[0082] Specifically, the bushing member 25 includes a pair of sliding pins 26 connected to the gear 5 which is slidably connected to corresponding grooves defined in the second tubular member 11 .

[0083] The contraction of the elastic means 21 causes the gear set to be displaced towards the second end position, ie from the second fork F2 towards the first fork F1 .

[0084] Conveniently, the movement means 6 comprise at least one actuating cable 22 connected between the gear set 4 and an actuating control of the bicycle B and at least partially housed inside the first tubular member 10 .

[0085] In more detail, the actuation cable 22 is attached to one end of the bushing member 25 .

[0086] By actuating the controller, the actuation cable 22 is tightened or released.

[0087] The tensioning of the actuating cable 22 causes the gear set 4 to slide towards the second end position, thereby counteracting the elastic means 21 .

[0088] On the other hand, the release of the actuating cable 22 causes an opposite movement towards the first end position via the elastic means 21 .

[0089] The moving device 6 comprises at least one pulley member 23 which is rotationally connected to the first tubular member 10 at the first end portion 15 and around which the actuating cable 22 is at least partially wound.

[0090] The pulley member 23 is at least partially arranged within the first tubular member 10 .

[0091] Basically, the actuation cable 22 extends from the actuation controller along the second fork F2 , fits inside the first tubular member 10 through the second end portion 16 , is partially wound around the pulley member 23 , and is attached to the bushing member 25 of the gear set 4 .

[0092] The movement device 6 comprises at least one support roller 24 which is connected in rotation with the central support shaft 2 at the second end 8 and on which the actuating cable 22 is at least partially wound.

[0093] The support roller 24 supports the actuation cable 22 during tensioning / releasing by the actuation controller.

[0094] Conveniently, the selection system 1 comprises at least one flywheel mechanism operatively interposed between the hub member 3 and the central support shaft 2 .

[0095] Flywheel mechanisms are known to those skilled in the art and allow the movement of the hub member 3 to be decoupled from the movement of the gear set 4 .

[0096] Even when the user does not actively operate the gear set 4, the flywheel mechanism allows the wheels R to move in the driving direction.

[0097] The operation of the selection system 1 according to the invention is as follows.

[0098] When the bicycle is in use, the central support shaft 2 is in the working position and allows the wheel R to rotate.

[0099] The rotation of the gear set 4 causes the rotation of the second tubular member 11 , thereby causing the hub member 3 supporting the wheel R to rotate.

[0100] To change the transmission gear, the actuating cable 22 is tightened / released to move the gear set 4 towards the second end position or the first end position, respectively.

[0101] In particular, the actuation cable 22 runs over the elastic device 21 , thereby causing a contraction or extension of the actuation cable 22 .

[0102] To replace wheel R, move the center support shaft to the removal position.

[0103] To do this, the actuating cable 22 is released, thereby moving the gear set to the first end position, after which the retaining member 17 is removed from the first end portion 15 to allow the first end 7 to be moved away from the first fork F1 .

[0104] At this point, the central support shaft 2 is partially pulled out by the second fork F2 to release the hub member 3. During this operation, the first end 7 moves close to the second fork F2 and compresses the elastic means 21.

[0105] Therefore, the locking member 20 is rotated to prevent the center support shaft 2 from returning to the working position.

[0106] At the end of the replacement operation, the central support shaft 2 is moved into the working position, inside the operating seat 9 of the hub member 3 , and is attached to the first fork F1 by means of the retaining member 17 .

[0107] It has been established in practice that the described invention achieves the intended purposes and it is particularly emphasized that the system for selecting the transmission gears in a bicycle or the like according to the invention allows, thanks to the particular construction of the central support shaft and of the shifting device, to keep the chain straight and axial during use while allowing simple and quick wheel changes.

[0108] Furthermore, unlike solutions of known type, the present selection system allows easy wheel replacement without compromising the strength and efficiency of the frame itself, by operating on the central support axle to replace the wheel, rather than on the bicycle frame.

Claims

1. A transmission gear selection system for a bicycle (1), comprising: at least one central support shaft (2) of a wheel (R) of a bicycle (B), said at least one central support shaft (2) being connected to a pair of forks (F1, F2) of said bicycle (B); at least one hub member (3), the at least one hub member (3) being rotatably and detachably connected to the central support shaft (2), and the at least one hub member (3) being arranged at a first fork (F1) of the bicycle (B); at least one gear set (4), the at least one gear set (4) being rotatably and axially slidably connected to the central support shaft (2), and the at least one gear set (4) being provided with a plurality of gears (5) of different sizes, arranged side by side from the smallest gear (5a) to the largest gear (5b); a moving device (6) of the gear set (4), the moving device (6) being between a first end position and a second end position on the central support shaft (2), wherein in the first end position, the moving device (6) is arranged at a second fork (F2) of the bicycle (B) and the smallest gear (5a) is located at a drive chain (C) of the bicycle (B); and in the second end position, the moving device (6) is moved away from the second fork (F2) and the largest gear (5b) is located at the chain (C); The invention is characterized in that the central support shaft (2) comprises: a first end (7) and a second end (8), the first end (7) being connected to the first fork (F1) in a detachable manner, the second end (8) being axially slidably connected to the second fork (F2), the central support shaft (2) being slidable relative to the fork (F1, F2) between a working position and a disassembly position, in which the central support shaft (2) is inserted between the fork (F1, F2) and the first end (7) is connected to the first fork (F1); in the disassembly position, the central support shaft (2) is at least partially pulled out of the fork (F1, F2) through the second fork (F2) and the first end (7) is moved away from the first fork (F1) to disassemble or assemble the wheel (R).

2. The selection system (1) according to claim 1, characterized in that The central support shaft (2) comprises at least a first tubular member (10) and a second tubular member (11), wherein the first tubular member (10) is connected to the fork-shaped member (F1, F2), and the second tubular member (11) is connected to the outside of the first tubular member (10), and the first tubular member (10) and the second tubular member (11) are locked together to slide and relatively rotate and move, and support the gear set (4).

3. The selection system (1) according to claim 2, characterized in that The first tubular member (10) comprises a first end portion (15) and a second end portion (16), wherein the first end portion (15) is connected to the first fork-shaped member (F1), and the second end portion (16) is movably and slidably connected to the second fork-shaped member (F2).

4. The selection system (1) according to claim 3, characterized in that It comprises at least one retaining member (17) of said first end portion (15) relative to said first fork (F1).

5. The selection system (1) according to claim 1, characterized in that It comprises at least one locking member (20) connected to the second end (8) and adapted to operate with the second fork (F2) to bring the central support shaft (2) into the disassembled position.

6. The selection system (1) according to claim 2, characterized in that The gear set (4) is locked and connected with the second tubular member (11) in rotation and axial sliding.

7. The selection system (1) according to claim 1, characterized in that The hub member (3) defines an operating seat (9), the central support shaft (2) is inserted into the operating seat (9) at the working position, and the central support shaft (2) is movably slidable relative to the operating seat (9) between the working position and the disassembly position.

8. The selection system (1) according to claim 3, characterized in that The moving device (6) comprises an elastic device (21), which is used to push the gear set (4), the elastic device (21) is connected to the outside of the first tubular member (10), the elastic device (21) is operably inserted between the gear set (4) and the first end (7), and is suitable for applying pressure to the gear set (4) towards the first end position.

9. The selection system (1) according to claim 8, characterized in that The movement device (6) comprises at least one actuating cable (22) connected between the gear set (4) and an actuating control of the bicycle (B) and at least partially accommodated in the first tubular member (10), the tensioning of the actuating cable (22) determining the sliding of the gear set (4) towards the second end position, thereby counteracting the elastic device (21).

10. The selection system (1) according to claim 9, characterized in that The moving device (6) comprises at least one pulley member (23) which is rotationally connected to the first tubular member (10) at the first end portion (15) and around which the actuating cable (22) is at least partially wound.

11. The selection system (1) according to claim 9, characterized in that The moving device (6) comprises at least one supporting roller (24) which is rotatably connected to the central supporting shaft (2) at the second end (8) and on which the actuating cable (22) is at least partially wound.

12. The selection system (1) according to claim 1, characterized in that It comprises at least one flywheel mechanism which is operably interposed between the hub member (3) and the central support shaft (2).

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