Crankset for a bicycle with removable cranks

Description

[0001] The invention relates to a bicycle crankset, as well as a bicycle comprising a frame equipped with such a crankset.

[0002] It applies in particular to the cranksets fitted to children's bicycles, especially bicycles intended for young children.

[0003] We know of cranksets that include: a shaft mounted for rotation in a housing and comprising two ends on each of which is fixed a pedaling crank, in order to allow the cyclist to drive said shaft in rotation by pressing his feet on pedals equipping each of said cranks; at least one chainring fixed to said shaft, so as to transmit its rotational torque to a mechanism for moving the bicycle, for example a sprocket fixed for rotation to a rear wheel of said bicycle.

[0004] In particular, there are cranksets whose shaft has two ends on which respectively a crank arm base is mounted by means of a reversible association system, so that the crank arms can be removed if necessary.

[0005] This design allows the bike to be used like a balance bike, especially for young children. It also prevents theft of the cranks when the bike is not in use, for example, when parked in a public place.

[0006] Document WO-2018 / 216676 describes such a bicycle, in which the two cranks are associated with the shaft by means of a reversible association system comprising a rod mounted in a bore formed in the shaft, said rod having a first end permanently fixed to a base of one crank and a second end intended to protrude from the base of the other crank when mounted on the shaft, a component being reversibly associated on said second end to fix said cranks to the shaft.

[0007] In particular, the organ has a rear button which is mounted on the second end of the rod by means of an elastically deformable element between a closed position, in which said element is engaged in a groove of said rod to secure the cranks to the shaft, and an open position for releasing said cranks.

[0008] This solution is not entirely satisfactory, as it proves to be relatively complex to use since the tightening of the cranks on the shaft is achieved by engaging the component on the rod.

[0009] The invention aims to improve the prior art by proposing in particular a bicycle crankset in which the cranks are reversibly associated with the rotating shaft in a simple and reliable way.

[0010] To this end, according to a first aspect, the invention proposes a bicycle crankset comprising a shaft mounted for rotation in a housing and at least one chainring fixed to said shaft for transmitting the rotational torque to a bicycle movement mechanism, said shaft having two ends on which respectively a crank arm base is mounted by means of a reversible association system comprising a rod mounted for rotation in a bore formed in the shaft, said rod having a first end provided with a thread protruding from the base of a first crank arm to cooperate with an axial clamping nut for the crank arms in the mounted position on the shaft, the rod having a second end which protrudes from the base of the second crank arm, said second end being equipped with a manual actuating element for rotating the rod in a tightening direction,said component having an anti-reverse device to prevent rotation in the opposite direction of loosening, said device being manually deactivateable to release the actuation of the rod in the direction of loosening for the purpose of dismantling the cranks.

[0011] According to a second aspect, the invention proposes a bicycle comprising a frame equipped with such a crankset, in which the housing of said crankset is integrated into said frame.

[0012] Other features and advantages of the invention will become apparent in the following description, made with reference to the accompanying figures, in which: [ Fig.1a ] And [ Fig.1b ] schematically represent a bicycle crankset according to an embodiment of the invention, respectively in perspective ( figure 1a ) and in longitudinal section ( figure 1b ) ; [ Fig.2 ] partially represents in longitudinal section a bicycle crankset according to a variant of the realization of figures 1a et 1b ; Fig.3 ] represents in partially exploded perspective the bicycle crankset of figures 1a et 1b , the case not being shown; Fig.4a ] And [ Fig.4b ] partially represent in longitudinal section the manual actuation mechanism of the pedal assembly of the figure 2 , in which the anti-return device is respectively activated ( figure 4a ) and disabled ( figure 4b ) ; [ Fig.5 ] represents, in perspective view from the rear, the actuation mechanism of the preceding figures; [ Fig.6 ] represents the view from the front of the anti-reverse crown of the crank in the previous figures; [ Fig.7 ] represents in lateral view the cooperation between the respective anti-return rings of the actuating member and the crank (not shown) of the previous figures.

[0013] In relation to these figures, a bicycle crankset is described below, as well as a bicycle comprising a frame equipped with such a crankset.

[0014] The crankset includes a shaft 1 mounted for rotation in a housing 2 and at least one chainring 3 attached to said shaft to transmit the rotational torque to a mechanism for moving the bicycle.

[0015] In the embodiment shown, the housing 2 is formed from an independent tubular piece intended to be fixed in a recess provided for this purpose in the frame of a bicycle (not shown). Alternatively, the housing 2 can be integrated into the bicycle frame, being formed as a single piece with said frame.

[0016] On the figures 1b And 2 , the shaft 1 is mounted in the housing 2 via two bearing supports 4a, 4b, which are interposed between said housing and respectively a first 5a and a second 5b carried from the periphery of said shaft.

[0017] At least one bearing 5a, 5b has a shoulder 7 on which the corresponding bearing 4a, 4b is in axial stop, a ring 6a, 6b being mounted on the housing 2 to ensure the preload of said bearing on said shoulder.

[0018] In the description, the terms of positioning in space are taken with reference to the axis of rotation of tree 1 (horizontal on the figures1b And 2 ), and are relative to a direction respectively parallel and perpendicular to this axis for the terms "longitudinal" and "radial", a positioning respectively close and far from this axis for the terms "interior" and "exterior".

[0019] In the figures, each bearing 5a, 5b has such a shoulder 7, the pedal assembly comprising a first 6a and a second 6b bushing to ensure the preload of a bearing 4a, 4b on the first bearing 5a and the second bearing 5b respectively. In particular, each bushing 6a, 6b has a threaded outer periphery intended to cooperate with a threaded inner edge formed in one end of the housing 2 respectively.

[0020] The crankset further comprises two pedal cranks 8a, 8b, each having a base 9a, 9b intended to be associated with the shaft 1, and a free end 10a, 10b provided with a threaded bore 11 for attaching a pedal 12, as shown in the figure 1a , in order to allow the cyclist to rotate said shaft by pressing his feet on said pedals.

[0021] The shaft 1 has two ends 1a, 1b on which respectively a base 9a, 9b of a crank arm 8a, 8b is mounted by means of a reversible association system.

[0022] This arrangement allows the cranks 8a, 8b to be removed from the crankset, for example to allow the cyclist to use the bike as a balance bike, which is particularly advantageous in the case of a bike intended for a young child.

[0023] In particular, the platform 3 is fixed to the periphery of the shaft 1 by being mechanically dissociated from the cranks 8a, 8b, which allows a user to remove the cranks 8a, 8b from the shaft 1 while leaving said platform associated with said shaft, and thus facilitate the switch to balance bike mode.

[0024] In the figures, chainring 3 includes a toothed wheel designed to rotate a wheel of the bicycle, in particular the rear wheel, via a chain that is engaged with said wheel and at least one sprocket fixed to its rotation. Alternatively, chainring 3 can be adapted to rotate another type of drive mechanism for the bicycle, for example via a cardan shaft system.

[0025] The plate 3 is mounted on a sleeve 13 which is fitted onto a bearing 14 of the shaft 1, a retaining ring 15 being mounted at the rear of said bearing after said fitting to ensure the axial hold of said sleeve on said shaft.

[0026] On the figure 2 , the mounting range 14 of the plate 3 has a rear shoulder 14b in which the stop ring 15 is disposed after passing the sleeve 13.

[0027] Furthermore, as depicted on the figure 2 , the fitting area 14 may also have a front stop 14a, in particular formed by a shoulder in the periphery of the shaft 1, against which the sleeve 13 comes to axial support when mounted around said shaft.

[0028] The mounting surface 14 is made in the rear axial extension of a crank 8b mounting end 1b, which reduces the axial bulk of the crankset.

[0029] In particular, as depicted on the figures 1b And 2 , the mounting surface 14 is also formed in the axial front extension of a mounting surface 5b for a bearing 4b, so that the sleeve 13 is radially surrounded by the corresponding preload ring 6b when it is fitted onto the shaft 1.

[0030] The crank association system 8a, 8b comprises a rod 16 mounted for rotation in a bore 17 formed in the shaft 1, said rod having a first end 16a provided with a thread projecting from the base 9a of a first crank 8a to cooperate with a nut 18 for axially clamping the cranks 8a, 8b in the mounted position on the shaft 1.

[0031] On the figures 1b And 2 , the base 9a of the first crank 8a has a recess 19 formed opposite the shaft 1 and in which the nut 18 is placed. This arrangement protects the nut 18 against possible impacts, particularly against the feet and / or legs of the cyclist, in order to limit the risk of injury to said cyclist.

[0032] In particular, the nut 18 is prevented from rotating in the recess 19 by means of a key 20, as shown in the figure 2 .

[0033] The rod 16 further has a second end 16b which is projecting from the base 9b of the second crank 8b, being equipped with a manual actuation element 21 for rotating the rod 16 in a tightening direction, said element having an anti-return device to prevent rotation in the opposite direction of loosening, said device being manually deactivated to release the actuation of the rod 16 in rotation in the loosening direction for the purpose of dismantling the cranks 8a, 8b.

[0034] Thus, the cranks 8a, 8b are fixed on the shaft 1 by tightening in rotation a component 21, which constitutes a particularly simple and intuitive gesture, and also makes it possible to make said fixing more reliable.

[0035] In the figures, the plate 3 is fitted onto a bearing surface 14 formed in the axial extension of the mounting end 1b of the second crank 8b.

[0036] At least one base 9a, 9b of a crank 8a, 8b has a conduit 22a, 22b for mounting on the end piece 1a, 1b, the rod 16 being disposed in said conduit with its end 16a, 16b protruding opposite the shaft 1.

[0037] In the embodiment shown, the two bases 9a, 9b each have such a conduit 22a, 22b for mounting on the corresponding end piece 1a, 1b. In particular, the conduit 22a of the first crank 8a opens axially at the rear of the recess 19 for receiving the clamping nut 18.

[0038] On the figure 1b , each mounting conduit 22a, 22b has a conical section, the end 1a, 1b of the shaft 1 having a complementary section on which said conduit is mounted.

[0039] Furthermore, as shown on the figures 3 And 6at least one mounting conduit 22a, 22b and the end piece 1a, 1b of the shaft 1 on which it is mounted have a geometry that is not of revolution, in order to immobilize the crank 8a, 8b in rotation relative to the shaft 1 when it is mounted on said end piece.

[0040] The actuation member 21 includes a wheel 23 which is fixed on the second end 16b of the rod 16, the anti-return device being disposed between said wheel and the base 9b of the second crank 8b.

[0041] Especially : the second end 16b of the rod 16 has a tip 25 which is fixed by overmolding, fitting and / or snapping into a housing 26 provided for this purpose at the rear of the wheel 23; the base 9b has a recess 24 formed opposite the shaft 1, the anti-return device being disposed in said recess.

[0042] As depicted in particular on the figures 3 And 5 à 7, the anti-return device comprises two crowns 27, 28 which are rotationally fixed to respectively the base 9b of the second crank 8b and the actuating member 21, presenting two facing walls.

[0043] Each of the walls of the crowns 27, 28 carries geometric means which are arranged to permit rotation of one wall on the other only in the tightening direction, the crown 28 of the member 21 being constrained on the crown 27 of the base 9b to prevent rotation in the loosening direction and being movable relative to the crown 27 of the base 9b to release said rotation in the loosening direction.

[0044] The ring 27 of the base 9b is formed by a washer 29 which is fixed to said base. To do this, the washer 29 is placed in an additional annular seat provided for this purpose in the bottom of the recess 24 formed on the base 9b.

[0045] In particular, as depicted on the figures 3 , 4a , 4b And 7 , the washer 29 has a rear wall equipped with means for fixing in the recess 24, in the form of four pins 30 that are angularly equidistant, each of which engages in a complementary cavity 31 provided for this purpose in the bottom of the recess 24.

[0046] The crown 28 of the component 21 is mounted in translation in the wheel 23, a spring 32 being interposed between said wheel and said crown to constrain it elastically on the crown 27 of the base 9b in order to prevent rotation in the loosening direction, said spring being arranged to allow manual translation of the crown 28 of the component 21 away from the crown 27 of the base 9b in order to release said rotation in the loosening direction.

[0047] In the embodiment shown, the crown 28 of the organ 21 is formed on a ring 33 having an outer wall 34 for gripping for its manual movement, said ring being rotationally fixed to the actuating organ 21.

[0048] In particular, the ring 33 is integrated into the wheel 23 to form the actuation member 21 by means of the outer gripping wall 34, the wheel 23 coming into axial contact with the outer wall 34 to form with the ring 33 a closed button defining said member.

[0049] In the figures, the ring 33 comprises a radial annular wall 35 on a rear face of which is formed the crown 28, two springs 32 being arranged in support between a front face of said radial wall and a rear face of the wheel 21 to elastically constrain the ring 33 on the front wall of the base 9b of the second crank 8b.

[0050] Furthermore, the ring 33 includes a peripheral wall 34 which extends substantially axially from the front face of the radial wall 35, said peripheral wall having an external bearing surface 34a on which axial grooves are angularly equidistant, in order to facilitate the gripping of said peripheral wall by a user to manipulate the actuating member 21.

[0051] In relation to the figure 3 The peripheral wall 34 also has two diametrically opposed lugs 34b formed near its front edge, extending radially inwards. Similarly, the wheel 23 has two hooks 23a which bear axially against a lug 34b under the effect of the elastic stress exerted by the springs 32, in order to secure the wheel to the ring.

[0052] After mounting the first crank 8a on a fitting 1a of the shaft 1, the user places the second crank 8b on the other fitting 1b by inserting the rod 16 into the bore 17 of said shaft, so as to position the threaded end 16a in axial alignment with a tapped hole 18a formed for this purpose in the nut 18. Then, to finalize the assembly, the user grasps the peripheral wall 34 of the ring 33 to turn the knob 23 in the tightening direction.

[0053] To remove the cranks 8a, 8b from the bottom bracket 2, in particular to use the bicycle as a balance bike, the user grasps the peripheral wall 34 to pull the ring backwards, in order to disengage the anti-return rings 27, 28, then turns the ring 33 in the loosening direction while maintaining this pull, in order to unscrew the rod 16 from the nut 18.

[0054] As depicted on the figures 1a And 3, the front face of the wheel 23 has markings 36a, 36b, notably in the form of diagrams, to indicate to the user the manipulations to be carried out on the component 21 to disassemble the cranks 8a, 8b, for example: a first inscription 36a to indicate the axial pulling movement to be made on the ring 33 to release its rotation in the direction of loosening; and a second inscription 36b to indicate the direction of rotation to be made with the ring 33 to loosen the cranks 8a, 8b.

[0055] In relation to figures 5 à 7 , the geometric means of association of the crowns 27, 28 include pins 37 formed on the wall of one crown 27 and ramps 38 formed on the wall of the other crown 28, said ramps forming an annular sliding surface 38a for the pins 37 in the tightening direction and axial stops 38b preventing the sliding of said pins in the loosening direction.

[0056] In particular, the crown 27 of the base 9b comprises four pins 37 equidistant angularly on a front face of the washer 29, the crown 28 of the organ 21 comprising ten ramps 38 equidistant angularly on the rear face of the radial wall 35 of the ring 33.

Claims

1. Bicycle crankset comprising a shaft (1) rotatably mounted in a housing (2) and at least one chainring (3) connected to said shaft for transmitting rotation torque to a bicycle moving mechanism, said shaft having two endpieces (1a, 1b) on which respectively a base (9a, 9b) of a pedalling crank (8a, 8b) is mounted by means of a reversible association system comprising a rod (16) rotatably mounted in a bore (17) formed in the shaft (1), said crankset being characterized in that the rod (16) has a first end (16a) provided with a screwthread projecting from the base (9a) of a first crank (8a) to engage with a nut (18) for axially tightening the cranks (8a, 8b) in a position mounted on the shaft (1), said rod having a second end (16b) which projects from the base (9b) of the second crank (8b), said second end being equipped with a member (21) for manually actuating the rod (16) in rotation in a tightening direction, said member having a non-return device to prevent rotation in the opposite loosening direction, said device being manually deactivatable to release actuation of the rod (16) in rotation in the loosening direction for disassembly of the cranks (8a, 8b).

2. Bicycle crankset according to claim 1, characterized in that at least one base (9a, 9b) of a crank (8a, 8b) has a duct (22a, 22b) for mounting on the endpiece (1a, 1b) of the shaft (1), the rod (16) being arranged in said duct with its end (16a, 16b) projecting away from said shaft.

3. Bicycle crankset according to claim 2, characterized in that at least one mounting duct (22a, 22b) has a conical cross-section, the endpiece (1a, 1b) of the shaft (1) having a complementary cross-section on which said duct is mounted.

4. Bicycle crankset according to one of claims 2 or 3, characterized in that at least one mounting duct (22a, 22b) and the endpiece (1a, 1b) of the shaft (1) on which it is mounted have a geometry that is not rotationally symmetrical.

5. Bicycle crankset according to any one of claims 1 to 4, characterized in that the actuation member (21) comprises a knurled wheel (23) which is fixed to the second end (16b) of the rod (16), the non-return device being arranged between said knurled wheel and the base (9b) of the second crank (8b).

6. Bicycle crankset according to any one of claims 1 to 5, characterized in that the non-return device comprises two crowns (27, 28) which are secured in rotation to respectively the base (9b) of the second crank (8b) and the actuation member (21) by presenting two facing walls, each of said walls carrying geometric means (37, 38) which are arranged to allow rotation of one wall on the other only in the tightening direction, the crown (28) of the member (21) being constrained on the crown (27) of the base (9b) to prevent rotation in the loosening direction and being displaceable relative to the crown (27) of the base (9b) to release said rotation in the loosening direction.

7. Bicycle crankset according to claims 5 and 6, characterized in that the crown (28) of the member (21) is mounted in translation in the knurled wheel (23), a spring (32) being interposed between said knurled wheel and said crown to constrain it elastically on the crown (27) of the base (9b) in order to prevent rotation in the loosening direction, said spring being arranged to allow manual translation of the crown (28) of the member (21) away from the crown (27) of the base (9b) in order to release said rotation in the loosening direction.

8. Bicycle crankset according to one of claims 6 or 7, characterized in that the crown (28) of the member (21) is formed on a ring (33) having an outer gripping wall (34) for its manual displacement, said ring being secured in rotation to the actuation member (21).

9. Bicycle crankset according to any one of claims 6 to 8, characterized in that the geometric means comprise pins (37) formed on the wall of one crown (27) and ramps (38) formed on the wall of the other crown (28), said ramps forming an annular sliding surface (38a) for the pins (37) in the tightening direction and axial stops (38b) preventing sliding of said pins in the loosening direction.

10. Bicycle crankset according to any one of claims 1 to 9, characterized in that the chainring (3) is fixed to the periphery of the shaft (1).

11. Bicycle crankset according to claim 10, characterized in that the chainring (3) is mounted on a sleeve (13) which is fitted onto a bearing surface (14) of the shaft (1).

12. Crankset according to claim 11, characterized in that the bearing surface (14) is designed as an axial extension of an endpiece (1b) for mounting a crank (8b).

13. Bicycle crankset according to any one of claims 1 to 12, characterized in that the base (9a) of the first crank (8a) has a recess (19) formed opposite the shaft (1), the nut (18) being arranged in said recess.

14. Bicycle crankset according to any one of claims 1 to 13, characterized in that the shaft (1) is mounted in the housing (2) by means of two rolling bearings (4a, 4b) which are interposed between said housing and respectively a first bearing surface (5a) and a second bearing surface (5b) on the periphery of said shaft.

15. Bicycle comprising a frame equipped with a crankset according to any one of claims 1 to 14, wherein the housing (2) is integrated into said frame.