For bicycle (cycle vehicles in general), stem that can be folded laterally instantaneously about a vertical or near-vertical axis, and allowing storage/transportation/parking and also constituting a possible anti-theft system.
Regardless of whether the stems are of the quill type (urban cycles) or threadless type (sports cycles), existing instantaneous storage/transport stems (that support the handlebar) pivot coaxially with the steering axis of the front fork, which does not optimize the desired reduction in width and/or simplification of manufacturing (tight machining tolerances and dimension chain!) and makes the insertion of an antitheft system complex and expensive, with a key that often disturbs the upper part of the stem, that hinders placement of an accessory (for example smartphone) above the stem.
The problem solved by the invention is to minimize the width of the bicycle at the handlebar when it is desired to store it or to transport it or to park it, and/or to simplify manufacturing; and optionally to make it unrideable by separation from the steering and/or offset from the front wheel whenever required, by means of an antitheft key located on the side or on the front of the stem, which leaves the space above the stem perfectly free, that can thus also hold an accessory such as a smartphone, cyclometer, heart frequency meter, camera, etc., either directly or using an interface plate.
To achieve this, the invention is characterized by a foldable stem, supporting a handlebar, and that enables instantaneous folding down of said handlebar along the bicycle, optionally said stem is ergonomically adjustable and comprises: a fixed stem made secured in a hyperstatic manner by an optionally quick-release tightening means to a steering pivot (front fork), said stem body directly or indirectly supporting at least one rotation bearing on which a stem arm can oscillate whenever required and when necessary; said bearing being positioned to make a stem folding axis that is perfectly distinct from the axis of said steering pivot, while remaining parallel or nearly parallel to it, in other words almost vertical in a normal use position of the bicycle.
According to particular embodiments, and assuming that the bicycle is in a situation in which its two wheels are in line:
The appended drawings illustrate the invention.
The stem according to the invention is of the quill type with an antitheft key on the right side of the stem in the normal situation in which the bicycle is in use, as shown in
Since the locking pin is projecting in the storage or transport or parking situation as shown in
The locking lever of the fork pivot bevel is raised, as shown in
The locking level of the fork pivot bevel is lowered, as shown in
The stem according to the invention is of the threadless type with an antitheft key on the front of said stem in the normal situation in which the bicycle is in use, as shown in
Since the locking pin is projecting in the storage or transport or parking situation as shown in
With reference to these drawings, a bicycle (1) equipped with a foldable stem (7) comprises a body (8) fixed to the fork pivot (3), a stem arm (9) oscillates on this body (8) making use of at least one bearing screw (10), that forms a rotation axis perfectly distinct from the fork pivot (3) and that is substantially vertical, so that the handlebar (5) can fold down substantially horizontally along the bicycle (1).
A blocking means (13), preferably associated with an antitheft lock (14) with key (15), solidarizes and therefore immobilizes said stem arm (9) with the body (8) so that the bicycle can be used normally; the key (15) can then be removed; said locking means (13) controlled by the key (15) can release said locking means (13) which separates the locking arm (9) facing the body (8), thus making the bicycle unrideable, since the key (15) has been removed.
According to a first particular embodiment, intended more specifically for an urban type bicycle illustrated on
To facilitate the ease and speed of adjustment, a lever (31) acts through a cam (32) that cooperates with a pad (35) on a cylinder (38) with a radial penetration that holds the head of said screw (33), increasing or reducing the tension applied on the screw (33) by maneuvering said lever (31). A decorative and protective bellows (36) is inserted between the steering column (4) of the bicycle (1) and the stem (7). Said quill (34) is fixed (single-piece, tightened by screw, force fitted, welding, etc.) onto the body (8) of the stem (7).
The body (8) is provided with a collar in its front part that tightens a left core (30) coaxial with said collar by means of screws (24), this core (30) carries the locking means (13) that in this case is a pin (13) protected by an O-ring (28). These tightening screws (24) release the tightness of said collar and therefore incline the stem arm (9) whenever required before retightening.
Another core (29) coaxial with the collar of the body (8) and to the right of the collar, acts as a support for the screws (10) that form rotation bearings of the stem arm (9), that clearly represents the concept of folding the stem (7); preferably to make the oscillating rotation of the stem arm (9) reliable, shouldered spacers (11) for example made of brass, are inserted between the screws (10) and the core (29).
The lock (14) is housed in the core (29) coaxial with the collar of the body (8) and on the right side of the body (8), and consequently is also coaxial with the core (29); the cylinder of the lock (29) actuated by the key (15) drives a transmission shaft that has an eccentric pin (17) at its left end, said pin (17) acts like a cam that raises or lowers the pin (13), locking or releasing the stem arm (9) at will and depending on requirements.
For reliability reasons, the hole (12) in the stem arm (9) will be in a sleeve formed by a shouldered ring (27) made for example from hardened steel.
In order to reduce clearances between the pin (13) that will be as long as possible and perfectly adjusted to slide in the core (30), and the ring (27), they will have conjugate tapered shapes that under the pressure of a spring (21) pushing under the pin (13), the spot facing forming the housing for the pin (17) contributes to cancelling parasite clearances.
Advantageously, the stem arms (9) will be provided with attachment means such as at least one threaded hole (26) to fix an accessory, in this case a smartphone (39), either directly or using an interface plate.
Also advantageously, the half-collar (22) that tightens the handlebar (5) either directly or through a fixing ring (25), will be provided with an attachment means, for example for a basket support (6) in this case, or a light.
According to a second particular embodiment, and intended more particularly for a sports type bicycle, illustrated by
In this case directly, the stem body (8) acts as a support to the screws (10) that form rotation bearings for the stem arm (9) that also represents the concept of folding the stem (7); preferably, the shouldered spacers (11) are inserted between the screws (10) and the stem body (8).
The lock (14) is housed in the stem arm (9) and the rotation axis of its cylinder is in the longitudinal vertical median plane of said stem arm (9), and under the attachment half-collar (22) of the handlebar, preferably this half-collar (22) is fixed to the stem arm (9) by a hinge pin (23) and tightening screws (24); the cylinder of the lock (14) actuated by the key (15) drives an eccentric pin (17), said pin (17) acts like a cam that lifts or lowers the pin (13), locking or releasing the stem arm (9) at will and as necessary.
For reliability reasons, the hole (12) in the stem arm (9) will be in a sleeve formed by a shouldered ring (27) made for example from hardened steel.
In order to reduce clearances between the pin (13) that will be as long as possible and perfectly adjusted to slide in the stem arm (9), and the ring (27), they will have conjugate tapered shapes that under the pressure of a spring (21) pushing under the pin (13), the spot facing of which forming the housing for the pin (17) contributes to cancelling parasite clearances.
Preferably, indexing notches (20) are made in the body (8) so that an indexer (18) housed in the stem arm (9) and pressurized by a spring (19) can precisely position said stem arm (9) on the running and parking positions.
Not illustrated, the locking pin (13) could have a specific housing with or without an angular clearance in the locking arm (9) of the handlebar (5) when the handlebar is folded back laterally along the bicycle, replacing dissuasion against stealing the bicycle that was previously obtained by the handlebar (5) being unusable for steering, by a dissuasion in which the handlebar is locked in position with or without angular clearance, folded back along the bicycle.
Advantageously, the stem arms (9) will be provided with attachment means such as at least one threaded hole (26) to fix an accessory, in this case a smartphone (39), either directly or using an interface plate.
As an additional security, the attachment screws (24) could be antitheft screws, for example having a head that cooperates with a coded tool for screwing and especially for unscrewing said screws (24), further reinforcing dissuasion against theft of the bicycle.
It is clear that the function to lock/unlock the stem arm (9) using a lock (14) actuated by a key (15) can be implemented for example by a simple push button, replacing the lock (15) if the antitheft function is not required.
The solutions in the two example embodiments, with a key (15) on the side of the body (8) or on the front of the stem arm (9), can be mixed without going outside the framework of the invention.
Note that on
The stem according to the invention is intended particularly for bicycles and cycles in general, in order to facilitate storage, transport and parking by reducing the overall width governed by the handlebar, while optionally providing dissuasion against theft, dissuasion based on the principle of reconstruction of a function enabling use of the bicycle and not on simple destruction of the antitheft means.
Number | Date | Country | Kind |
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17/01296 | Dec 2017 | FR | national |
This application is a § 371 application from PCT/FR2018/000266 filed Dec. 10, 2018, which claims priority from French Patent Application No. 17 01296 filed Dec. 11, 2017, each of which is herein incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/FR2018/000266 | 12/10/2018 | WO | 00 |