Bicycle stem

Abstract

A bicycle stem comprising a base (19) adapted to be fixedly connected to the steering pivot (8) of a bicycle and a stem body (9) to which a bicycle handlebar (3) can be attached. The stem body (9) is detachably connectable to the base (19) by means of a bayonet fitting. The bayonet fitting allows the stem body (9) to be connected to the base (19) by pushing the stem body (9) against the base (19) along an engagement axis (A), and then by rotating the stem body (9) relative to the base (19) around the engagement axis (A). (Figure 4)

Description

Title of the invention: Bicycle stem technical field

[0001] The invention relates to a bicycle stem. This stem can be mounted on any type of bicycle. Background

[0002] A bicycle stem is a component that connects the handlebars of a bicycle to the steering pivot, also called the fork steerer tube, in the upper part of the bicycle fork. Some bicycles are equipped with a stem that allows the handlebars to be rotated 90° relative to the steering pivot in order to orient the handlebars parallel to the median plane of the bicycle's front wheel. The handlebars then no longer protrude on either side of the front wheel, which facilitates bicycle storage. Stems of this type are described, for example, in patent documents NL 2005592 A and DE 102011054696 AL. However, these stems do not allow the handlebars to be quickly detached from the rest of the bicycle. Detaching the handlebars could prove useful for preventing the bicycle from being used (and thus reducing the risk of theft) or for facilitating its storage.

[0003] There is therefore a need for a bicycle stem which not only allows the orientation of the handlebars relative to the steering pivot to be changed simply (i.e. without having to dismantle any part and without special tools), but which also allows the handlebars to be detached simply and quickly from the rest of the bicycle, while ensuring a robust and reliable mechanical connection between the handlebars and the steering pivot in the position of use. General presentation

[0004] A bicycle stem according to the invention comprises a base adapted to be fixedly connected to the steering pivot of the bicycle and a stem body to which the handlebars of the bicycle can be attached. The stem body is detachably connectable to the base by means of a bayonet fitting.

[0005] The bayonet fitting allows the connection of the stem body to the base by pushing the stem body against the base, along an engagement axis, then by rotation (in a first direction of rotation) of the stem body relative to the base, around the engagement axis.

[0006] Conversely, the bayonet fitting allows the boom body to be disconnected (i.e., detached) from the base by rotating (in the opposite direction to the first direction of rotation) the boom body around the engagement axis and pulling axially the The stem body is moved away from the base. This allows the stem body, and with it the handlebars, to be easily and quickly detached from the rest of the bike.

[0007] Furthermore, the bayonet mount allows for easy adjustment of the handlebar orientation relative to the steering pivot, as explained in detail below. Finally, the bayonet mount has the advantage of being simple and robust.

[0008] The invention also relates to a bicycle comprising handlebars, a steering pivot, and a stem according to the invention, the stem connecting the handlebars to the steering pivot. The bicycle may have two or more wheels (bicycle, tricycle, etc.), be motorized or not (electrically assisted bicycle, pedelec, moped, etc.), be foldable or not, the invention not being limited to any particular type of bicycle.

[0009] Other features and advantages of the invention will become apparent from the following detailed description. This detailed description refers to the accompanying drawings. Brief description of the drawings

[0010] The accompanying drawings are schematic and not necessarily to scale; their primary purpose is to illustrate the principles of the invention. In these drawings, identical elements (or parts of elements) are identified by the same reference numerals from one figure (fig) to another. [Fig.1] This figure represents in perspective the front part of a bicycle and the upper part of the fork of this bicycle equipped with an example of a bicycle stem according to the invention. [Fig.2] This figure is a view analogous to that of [Fig.1], in which the clamping system of the stand is loosened. [Fig.3] This figure is a view analogous to that of figures 1 and 2, in which the stem and handlebar of the bicycle are rotated 90° relative to the steering pivot of the bicycle. [Fig.4] This figure is a view analogous to that of figures 1 to 3, in which the handlebars of the bicycle are detached. [Fig.5] This figure is an exploded view of an example of a gallows according to the invention. [Fig.6] This figure is an axial cross-sectional view of the stem of [Fig.5] when the handlebar is detached. [Fig.7] This figure is an axial cross-sectional view of the stem when the handlebar is attached to the rest of the bicycle. [Fig.8] This figure is an axial cross-sectional view similar to that of [Fig.7], but in which the hook of the gallows is unhooked. [Fig.9] This figure is a cross-sectional view of the gantry along plane IX-IX of [Fig.7]. [Fig. 10] This figure is a cross-sectional view of the gantry similar to that of [Fig. 9]. Detailed description

[0011] Specific embodiments of the proposed bicycle stem are described in detail below, with reference to the example shown in the accompanying drawings. These embodiments illustrate the features and advantages of the invention. It should be noted, however, that the invention is not limited to these embodiments or to the example shown.

[0012] In certain embodiments and in the example shown in the figures, the stem 2 comprises a base 19 adapted to be fixedly connected to the steering pivot 8 of a bicycle 1, and a stem body 9 to which a bicycle handlebar 3 can be attached. The steering pivot 8 is connected to the fork 4 of the bicycle 1. The steering pivot 8 is rotatably mounted in the head tube 7 located at the front of the bicycle 1. The base 19 is fixedly connected to the steering pivot 8. In the example shown, the head tube 7 is located at the junction of the top tube 5 and the down tube 6 of the bicycle frame.

[0013] In certain embodiments and in the example shown, the base 19 is fixedly connected to the steering pivot 8 by a known plunger-type system comprising an axial tube 20 extending inside the steering pivot 8, a clamping screw 24 extending inside the axial tube 20, and a shim 22 connected to the clamping screw 24. The axial tube 20 is surmounted by a wider portion forming the head 49 of the base 19. One end (i.e., the screw head) of the clamping screw 24 bears against the head 49 of the base 19, and the other end of the screw 24 is screwed into the shim 22. The lower end of the axial tube 20 has a first oblique surface 21, and the upper end of the shim 22 has a second oblique surface 22. When the screw 24 is loosened, the shim 22 is centered axially and it does not oppose the sliding of the axial tube 20 inside the steering pivot 8 which surrounds it.When the screw 24 is tightened, the oblique surfaces 21, 22 come into contact with each other, causing a decentering (i.e., a radial offset) of the wedge 22. The wedge 22 then opposes the sliding of the axial tube 20 inside the steering pivot. Other fastening systems can be considered to permanently connect the base 19 to the steering pivot 8 without departing from the scope of the invention.

[0014] In the example shown, the handlebar 3 is fixed to the front end of the stem body 9 by a jaw 10 which can be tightened by means of screws 18.

[0015] The stem body 9 is connectable to the base 19, in a detachable manner, by means of a bayonet fitting. The bayonet fitting allows the stem body 9 to be connected to the base 19 by pushing the stem body 9 against the base 19, along an engagement axis A, and then by rotating the stem body 9 relative to the base 19, around the engagement axis A. In the example of the figures, the engagement axis A corresponds to the axis of rotation of the direction pivot 8.

[0016] In certain embodiments and in the example shown in the figures, the stem body 9 has an angled shape with a lower portion 9b extending along the engagement axis A and an upper portion 9a forming an angle with the lower portion 9b. The upper portion 9a extends towards the front of the bicycle when the stem 2 is in the operating position and when the front and rear wheels of the bicycle 1 are aligned. See Figures 1 and 2. The lower end of the lower portion 9b is connectable to the base 19. The handlebar 3 is attached to the front end of the upper portion 9a.

[0017] In this application, horizontal and vertical are defined with respect to the operating position of bicycle 1 on a horizontal surface. Top and bottom are defined with respect to the vertical direction. Front and rear are defined with respect to the normal direction of travel of bicycle 1. The axial direction corresponds to the direction of the axis of engagement A. A radial direction is a direction perpendicular to and intersecting the axis of engagement A. Similarly, an axial plane is a plane containing the axis of engagement A, and a radial, or transverse, plane is a plane perpendicular to this axis. Finally, unless otherwise specified, the adjectives inside and outside are used with reference to a radial direction, such that the inside part of an element is, along a radial direction, closer to the axis of engagement A than the outside part of the same element.

[0018] In certain embodiments and in the example shown, the bayonet fitting comprises at least one radial finger 37a, 37b and at least one L-shaped groove 46a, 46b. Each groove 46a, 46b comprises a circumferential segment 36a, 36b in the form of an arc around the engagement axis A and an axial segment 26a, 26b parallel to the engagement axis A. Each radial finger 37a, 37b can be engaged and slide in its corresponding groove 46a, 46b. In the example shown in the figures, the bayonet fitting comprises two radial fingers 37a, 37b, diametrically opposed with respect to the engagement axis A, and two corresponding grooves 46a, 46b. See Figures 4, 5, 9, and 10.

[0019] In certain embodiments and in the example shown in the figures, when each radial finger 37a, 37b is engaged in its corresponding groove 46a, 46b, the boom body 9 is rotationally mobile relative to the base 19, around the engagement axis A, between an operating position in which the radial finger 37a, 37b is located at one end of the circumferential segment 36a, 36b and a disconnected position in which the radial finger 37a, 37b is located at the other end of the circumferential segment 36a, 36b in alignment with the axial segment 26a, 26b. In the operating position, shown in Figures 1, 7 and 9, the axial movement of the boom body 9 relative to the base 19 is prevented by the engagement of the radial finger 37a, 37b in the circumferential segment 36a, 36b. From the disconnected position, shown in Figures 3 and 10, the stem body 9 can be disconnected from the base 19 by sliding the radial finger 37a, 37b in the axial segment 26a, 26b so as to disengage the radial finger 37a, 37b from the groove 46a, 46b. The disconnected position is therefore an intermediate position, between the working position and the disconnected position, from which the stem body 9 can be easily disconnected from the base 19. Furthermore, in this disconnected position, the overall size of the handlebar 3 is reduced, as the handlebar (i.e., the general direction of the handlebar) is no longer oriented perpendicular to the median plane of the front wheel of the bicycle but rather parallel to it.

[0020] In certain embodiments and in the example shown in the figures, the operating position and the disconnected position are angularly separated by a rotation angle of 90°. The transition from the operating position to the disconnected position is illustrated in Figures 2 and 3. In [Fig. 2], the stem body 9 is in its operating position. In the operating position, the handlebar 3 is oriented perpendicular to the median plane of the front wheel and cannot be detached from the base 19. In the disconnected position, the handlebar 3 is oriented parallel to the median plane of the front wheel (the overall size of the handlebar 3 is then reduced to a minimum) and can be easily detached from the base 19.

[0021] As illustrated by the two curved arrows in [Fig. 3], to disconnect the stem body 9 from the base 19, the handlebar 3 is rotated 90° relative to the median plane of the front wheel. The stem body 9 is thus brought into the disconnected position. It is then possible to disconnect, or detach, the stem body 9 from the base 19 by pulling it axially upwards as illustrated by the arrow in [Fig. 4]. The handlebar 3 is then detached from the rest of the bicycle 1. The bicycle 1 without its handlebar 3 is unusable, which reduces the risk of theft. In addition, the bicycle 1 without its handlebar 3 is even less bulky, which facilitates storage. This is particularly advantageous in the case of a folding bicycle, as the handlebar 3 can be detached to minimize the size of the folded bicycle. An example of a folding bicycle is described in patent EP 3634842 B1.

[0022] Conversely, to attach the handlebar 3 to the rest of the bicycle 1 from the position shown in [Fig. 4], the stem body 9 is pushed axially downwards against the base 19, in the opposite direction to the arrow in [Fig. 4]. The stem body 9 is thus brought into the disconnected position shown in [Fig. 3]. From this disconnected position, the stem body 9 is rotated in the opposite direction to the arrows in [Fig. 3] until it reaches the operating position shown in [Fig. 2].

[0023] In certain embodiments and in the example shown in the figures, the arm 2 includes a hook 33 mounted on the arm body 9 and adapted for The stem body 9 engages in a first notch 38 in the base 19 to immobilize it in the operating position. In other words, when the hook 33 is engaged in the first notch 38, as shown in Figures 7 and 9, it is no longer possible to move, in particular to rotate, the stem body 9 relative to the base 19: the stem body 9 is fixed to the base 19 in rotation and axial translation. In this operating position, the steering pivot 8, and with it the fork 4 and the front wheel of the bicycle, can be oriented in the desired direction by turning the handlebars 3. In other words, in the operating position, it is possible to ride the bicycle.

[0024] In certain embodiments and in the example shown in the figures, the hook 33 is adapted to engage in a second notch 39 provided in the base 19 in order to immobilize the boom body 9 in the disconnected position. In other words, when the hook 33 is engaged in the second notch 39, the boom body 9 is in the disconnected position and it is no longer possible to move, in particular to rotate, the boom body 9 relative to the base 19: the boom body 9 is fixed to the base 19 in rotation and axial translation.

[0025] Figures 7 and 8 respectively show the hook 33 in the engaged and disengaged positions. Figures 9 and 10 respectively show the hook 33 engaged in the first notch 38 and in the second notch 39.

[0026] In certain embodiments and in the example shown in the figures, the hook 33 is pivotally mounted on the boom body 9 and is actuated by means of a lever 12. In the example shown in the figures, the hook 33 is pivotally mounted about a second axis 34 supported by the boom body 9. The hook 33 is driven in rotation about the second axis 34 by a lever 12 itself pivotally mounted about a first axis 32 supported by the boom body 9. The hook 33 comprises an axial arm 33a and a radial arm 33b extending on either side of the second axis 34. The lever 12 comprises two arms 12a, 12b extending on either side of the first axis 32. The first arm 12a of the lever extends on one side of the first axis 32 and is connected to the radial arm 33b of the 33 crochet hook.The second arm 12b of the lever 12 extends to the other side of the first axis 32 and forms a push button 12c which the user can press to rotate the lever 12 around the first axis 32, as illustrated by the arrows in Figures 3 and 8. The button 12c is located below the upper part 9a of the support body 9. In the example, a spring 27 is provided inside the support body 9 to hold the lever 12 in a stable position, shown in [Fig. 7], in which the button 12c is in its unpressed position, and the hook 33 is in its unhooked position. In the example, in the unpressed position, the button 12c protrudes below the upper part 9a of the support body 9 for easier access and manipulation.

[0027] In the example shown in the figures, the first and second axes 32, 34 are formed by shafts passing through the hook 33 and the lever 12, each supported by two bearings formed in the side walls of a support 28 that forms part of the boom body 9. The support 28 is housed inside the casing of the boom body 9 and fixed to this casing by screws 29. The hook 33 actuation mechanism is thus protected from external impacts. Other configurations are possible, however. In particular, the support 28 can be formed as a single piece with the rest of the boom body 9.

[0028] In certain embodiments and in the example shown in the figures, the radial arm 12a of the lever 12 carries a pin 35. In addition, an oblong opening 40 is provided in the radial arm 33b of the hook 33. The oblong opening 40 and the lever 12 are configured so that the pin 35 moves in and along the oblong opening 40 when the lever 12 is rotated about the first axis 32. The movement of the pin 35 in the oblong opening 40 then rotates the hook 33 about the second axis 34, as illustrated in Figures 7 and 8.

[0029] In certain embodiments and in the example shown in the figures, the support body 9 comprises a mounting foot 41, generally cylindrical in shape, about a first axis of revolution B1, while the base 19 comprises a mounting head 49, generally cylindrical in shape, about a second axis of revolution B2. The mounting foot 41 and the mounting head 49 are adapted to engage coaxially with each other. In the example shown in the figures, the mounting foot 41 forms the lower part 9b of the support body 9. The first axis of revolution B1 and the second axis of revolution B2 are aligned with each other and with the engagement axis A when the mounting foot 41 and the mounting head 49 are engaged with each other.

[0030] In some embodiments and in the example shown, the fixing foot 41 includes a sleeve 44 having as its central axis the first axis of revolution B1, and the fixing head 49 is adapted to be engaged coaxially in the sleeve 44.

[0031] In certain embodiments and in the example shown, the radial fingers 37a, 37b protrude inside the sleeve 41 and the grooves 46a, 46b are formed at the periphery of the fixing head 49. For each groove 46a, 46b, the circumferential segment 36a, 36b extends circumferentially around the fixing head 49 and the axial segment 26a, 26b extends axially along the fixing head 49, from the circumferential segment 36a, 36b to the upper end of the fixing head 49.

[0032] In certain embodiments and in the example shown, the support body 9 comprises a central rod 30 extending from the center of the sleeve 44 along the first axis of revolution B1, the locking hook 33 being housed inside the central rod 30. In this case, in the example shown, the axial arm 33a of the hook 33 is housed within the central rod 30, while the radial arm 33b extends outside the central rod 30. The central rod 30 is hollow and defines a recess 31 for the axial arm 33a of the hook 33. When the hook 33 pivots, it moves in or out of the recess 31 through an axial slot 31a provided along the central rod 30 and adjacent to the recess 31. In the extended or hooked position of the hook 33, the lower end of the hook-shaped axial arm 33a protrudes from the central rod 30, while in the retracted or unhooked position of the hook 33, the lower end of the axial arm 33a is fully housed within the recess 31. In this example, the central rod 30 is formed as a single piece with the support 28, but other configurations are possible.

[0033] In certain embodiments and in the example shown, a central hole 43 is provided in the fastening head 49 to receive the central rod 30 when the fastening head 49 is engaged in the sleeve 44. The central hole 43 and the central rod 30 both extend along the engagement axis A. The first notch 38 is provided in the side wall 45 delimiting the central hole 43. Similarly, when a second notch 39 is provided, the second notch 39 is provided in the side wall 45 delimiting the central hole 43.

[0034] In certain embodiments and in the example shown, the stem 9 further comprises a clamping system for tightening the sleeve 44 against the mounting head 49 when the mounting head 49 is engaged in the sleeve 4L. Such a system makes it possible to lock the relative position of the sleeve 44 with respect to the mounting head 49 while reducing the play between these parts. This makes it possible to obtain a stable and robust connection between the stem body 9 and the base 19. In the example, this system makes it possible to immobilize the stem body 9 in the operating position and reinforces the locking produced by the engagement of the hook 33 in the first notch 38.

[0035] In some embodiments and in the example shown, the sleeve 44 has a slot 17 extending along the sleeve 44 and the actuation of the clamping system makes it possible to reduce the gap (i.e. the width) of the slot 17. In the example in the figures, the slot 17 extends from the free end of the sleeve 44. When the gap of the slot decreases, the inner diameter of the sleeve 44 decreases and the sleeve 44 clamps the fixing head 49, which reduces the clearance between these parts.

[0036] In some embodiments and in the example shown, the clamping system includes a cam lever 11 associated with a clamping rod 14. The slot 17 of the sleeve 44 is bordered by two studs 16a, 16b through which the clamping rod 14 passes. Actuating the cam lever 11 brings the two studs 16a, 16b closer together and thus reduces the gap of the slot 17.

[0037] The embodiments described in this presentation are given by way of illustration and not limitation, a person skilled in the art being able to easily, in view of this presentation, modify these embodiments, or consider others, while remaining within the scope of the invention.

[0038] In particular, a person skilled in the art will readily be able to consider variations comprising only some of the features of the embodiments described above, if those features alone are sufficient to provide one of the advantages of the invention. Furthermore, the various features of these embodiments can be used individually or combined. When combined, these features can be used as described above or otherwise, the invention not being limited to the specific combinations described herein. In particular, unless otherwise specified, a feature described in relation to one embodiment can be applied analogously to another embodiment.

Claims

Demands

1. Bicycle stem comprising: a stem body (9) on which a bicycle handlebar (3) can be fixed, characterized in that it further comprises a base (19) adapted to be fixedly connected to the steering pivot (8) of a bicycle;in which the stem body (9) is connectable to the base (19), in a detachable manner, by means of a bayonet fitting, and in which the bayonet fitting allows the connection of the stem body (9) to the base (19) by pushing the stem body (9) against the base (19), along an engagement axis (A), and then by rotating the stem body (9) relative to the base (19), around the engagement axis (A), the bicycle stem further comprising a hook (33) mounted on the stem body (9) and adapted to engage in a first notch (38) provided in the base (19) in order to immobilize the stem body (9) in a working position in which the stem body (9) is fixed to the base (19) in rotation around the engagement axis (A) and fixed to the base (19) in translation along the engagement axis (HAS).;

2. Bicycle stem according to claim 1, wherein: the bayonet fitting comprises at least one radial finger (37a, 37b) and at least one L-shaped groove (46a, 46b); each groove (46a, 46b) comprises a circumferential segment (36a, 36b) in the form of an arc around the engagement axis (A) and an axial segment (26a, 26b) parallel to the engagement axis (A); and each radial finger (37a, 37b) can be engaged and slid into its corresponding groove (46a, 46b).

3. Bicycle stem according to claim 2, wherein: when each radial finger (37a, 37b) is engaged in its corresponding groove (46a, 46b) and when the hook (33) is in the unhooked position, the stem body (9) is rotationally movable relative to the base (19), around the engagement axis (A), between the operating position in which the radial finger (37a, 37b) is at one end of the circumferential segment (36a, 36b) and a disconnected position in which the radial finger (37a, 37b) is is found at the other end of the circumferential segment (36a, 36b) in alignment with the axial segment (26a, 26b); in the operating position, axial movement of the stem body (9) relative to the base (19) is prevented by the engagement of the radial finger (37a, 37b) in the circumferential segment (36a, 36b); from the disconnected position, the stem body (9) can be disconnected from the base (19) by sliding the radial finger (37a, 37b) in the axial segment (26a, 26b) so as to bring the radial finger (37a, 37b) out of the groove (46a, 46b).

4. Bicycle stem according to claim 3, wherein the hook (33) is adapted to hook into a second notch (39) provided in the base (19) in order to immobilize the stem body (9) in the disconnected position.

5. Bicycle stem according to claim 3 or 4, wherein the operating position and the disconnecting position are angularly separated by a rotation angle of 90°.

6. Bicycle stem according to any one of claims 1 to 5, wherein: the stem body (9) comprises a mounting foot (41) generally cylindrical about a first axis of revolution (B1); the base (19) comprises a mounting head (49) generally cylindrical about a second axis of revolution (B2); the mounting foot (41) and the mounting head (49) are adapted to be coaxially engaged with each other.

7. Bicycle stem according to claim 6, wherein: the fixing foot (41) comprises a sleeve (44) having as its central axis the first axis of revolution (Bl); and the fixing head (49) is adapted to be engaged coaxially in the sleeve (44).

8. Bicycle stem according to claim 7 and any one of claims 2 to 5, wherein each radial finger (37a, 37b) protrudes inside the sleeve (44) and each L-shaped groove (46a, 46b) is formed at the periphery of the fixing head (49).

9. Bicycle stem according to claim 7 or 8, wherein: the stem body (9) comprises a central rod (30) extending to the center of the sleeve (44) along the first axis of revolution (Bl); the hook (33) is housed partly inside the central rod (30); a central hole (43) is provided in the fixing head (49) to receive the central rod (30) when the fixing head (49) is engaged in the sleeve (44); and the first and / or second notch (38, 39) is provided in the side wall (45) delimiting the central hole (43).

10. A gallows according to any one of claims 7 to 9, further comprising a clamping system for clamping the sleeve (44) against the fixing head (49) when the fixing head (49) is engaged in the sleeve (44).

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