GB2429440A

GB2429440A - A bicycle having a stem

Info

Publication number: GB2429440A
Application number: GB0517348A
Authority: GB
Inventors: Jonathan Hudson
Original assignee: JOFF HUDSON DESIGNS Ltd
Current assignee: JOFF HUDSON DESIGNS LIMITED
Priority date: 2005-08-25
Filing date: 2005-08-25
Publication date: 2007-02-28
Anticipated expiration: 2025-08-25
Also published as: WO2007023314A1; GB2429440B; EP1917179A1; GB0517348D0

Abstract

A bicycle (1) comprises a frame (2), a rear wheel (4) coupled to the frame, a front fork (6) coupled between a front wheel (10) and handlebars (18). The handlebars (18) extend along a handlebar axis (26). The front fork (6) is pivotally coupled to the frame (2) using a steering column (8) such that the front fork (6) can pivot about a steering axis (28) to steer the front wheel (10). The front wheel is rotatable about a front wheel axis (12). The handlebars (18) are coupled to the front fork (6) by a stem (20). The stem has a handle portion (22) and a steering portion (24). The steering portion (24) is coupled to the front fork (6) such that it extends transverse to the steering axis to a first end (52) to which the handle portion (22) is coupled. The handle portion (22) couples the handlebars (18) to the steering portion (24). The handle portion (22) of the stem (20) is movable relative to the steering portion (24) between a steering position and a storage position. In the steering position the handle portion (22) is arranged adjacent the first end (52) of the steering portion (24) such that the handlebar axis (26) is arranged substantially parallel with the front wheel axis (12). In the storage position the handle portion (22) is rotated relative to the steering portion (24) such that the handlebar axis (26) is arranged at an angle of between 50{ and 100{ to the front wheel axis (12). The invention also provides a stem (20) for use in such a bicycle.

Description

A Bicycle Having a Stem

BACKGROUND

a. Field of the Invention

The present invention relates to a bicycle having a stem for assisting the storage of a bicycle to which it is attached. In particular, the invention relates to a bicycle having a stem which, when actuated, moves handlebars of the bike and holds them in a storage position. The invention extends to a stem for use with such a bicycle.

b. Related Art A typical bicycle comprises several major components, those being a frame, a rear wheel coupled to the frame and chain driven by pedals, a front fork pivotally coupled to the frame by a steering column and being attached to a front wheel and handlebars. The handlebars are typically coupled to the front fork so that they extend substantially parallel with the axis of rotation of the front wheel. The handlebars are arranged so that a user can use the handlebars to cause the front fork to pivot about a steering axis thereby steering the front wheel. The handlebars may be connected directly to the top of the steering column so that a centre of the handlebars is located on, and pivots about, the steering axis.

Recently there has been a move towards the use of a stem to couple the steering column to the handlebars so that the steering control and feedback can be fine tuned for a rider. A stem extends from the steering column transverse to the steering axis so that the handlebars are offset from the steering axis.

A common way of storing a bicycle is to lean it against a wall, with one end of the handlebars resting against the wall supporting the bicycle. However this is not a particularly satisfactory arrangement. The length of the handlebars can mean that the bicycle takes up a lot of space if the handlebars are arranged, as is typical, substantially perpendicular to the wall. In fact, if the bicycle is stored in a hallway or corridor, it can typically take up half the overall width. It is also noted that the bicycle is not particularly stable in this position as, if the bicycle is knocked, the handlebars can turn which causes pivoting of the front fork and movement of the front wheel which can then roll away from the wall causing the bicycle to fall over.

The use of a stem can exaggerate this problem.

It is known to provide apparatus allowing the handlebars to be rotated relative to the front fork for storage. Such apparatus includes hinges provided in the handlebars themselves so that each end of the handlebars can be pivoted independently so that they lie substantially perpendicular to the axis of rotation of the front wheel. However, this can make the handlebars bulky and reduce the choices available for a rider.

It has also been proposed to have a coupling between the handlebars and the front fork which can be released allowing the handlebars to be rotated about the steering axis relative to the front fork. These couplings typically require significant alteration to the bicycle and, in use, require a threaded coupling to be released by rotating an end of the coupling manually or with a tool to allow rotation of the handlebars and retightened to secure the handlebars relative to the front fork.

Insufficient tightening of the coupling may result in the handlebars not being secured correctly to the front fork which is unsafe as accurate steering control may be lost.

SUMMARY OF THE INVENTION

The invention provides a bicycle comprising a frame, a rear wheel coupled to the frame, a front fork coupled between a front wheel and handlebars, the handlebars extending along a handlebar axis, the front fork being pivotally coupled to the frame using a steering column such that the front forks can pivot about a steering axis to steer the front wheel, the front wheel being rotatable about a front wheel axis, the handlebars being coupled to the front fork by a stem, the stem comprising a handle portion and a steering portion, the steering portion being coupled to the front fork such that it extends transverse to the steering axis to a first end to which the handle portion is coupled, the handle portion coupling the handlebars to the steering portion wherein the handle portion of the stem is movable relative to the steering portion between a steering position and a storage position, in the steering position the handle portion is arranged adjacent the first end of the steering portion such that the handlebar axis is arranged substantially parallel with the front wheel axis, in the storage position the handle portion is rotated relative to the steering portion such that the handlebar axis is arranged at an angle of between 500 and 1000 to the front wheel axis.

The invention also relates to a stem for use in a bicycle as described above, the stem comprising a handle portion and a steering portion, the steering portion being for coupling to a steering column and extending to a first end to which the handle portion is coupled, the handle portion being for coupling the handlebars to the steering portion wherein the handle portion of the stem is movable relative to the steering portion between a steering position and a storage position.

The construction of the bicycle frame, wheels, handlebars and the front fork can be of any conventional construction and no detailed discussion of these components will be entered into. Handlebars are traditionally substantially symmetrical about a central portion and it is to this central portion that a stem is usually coupled. The handlebar axis is usually substantially co-axial with this central portion.

It is envisaged that the stem itself could be a replacement part sold through aftermarket channels to replace a standard stem, or could be original equipment for a bicycle.

The steering portion of the stem can extend at any suitable angle with respect to the steering axis as is conventional in the design field.

By having a stem that allows the handlebars to be rotated by between 50 and 1000 from their steering position the extent of the handlebars in the direction parallel with the front wheel axis can be greatly reduced. It is preferred that, in the storage position, the handlebar axis is between 70 and 100 to the front wheel axis and most preferably substantially 90 .

It is preferred that the handle portion of the stem is pivotally coupled to the steering portion such that the handle portion is pivotable about a pivot axis with respect to the steering portion. The pivot axis therefore offset from the steering axis, but may be substantially parallel with the steering axis.

In order to give the rider confidence in the bicycle the stem may include means for retaining the handle portion in the steering position and/or in the storage position.

Such retaining means may simply provide a resistive force that prevents pivoting or movement of the handle portion until a threshold force has been overcome.

Such a retaining means could be provided by, for example, a ball and spring retainer or a magnetic catch. However, it is preferable for rider confidence and safety that the handle portion can be substantially locked in the steering position.

This can be achieved in many ways, but such locking means may include conventional latches and locks which must be released before the handle portion can move.

The stem may include a lever attached to the steering portion which, when actuated, causes the handle portion to move with respect to the steering portion.

It is preferred that, in the steering position, the lever may lie substantially adjacent to, or overlie, the stem. The lever may also engage with the handle portion in the steering position to substantially lock the handle portion with respect to the steering portion.

The lever may be coupled to the handle portion in any suitable way, for example using gears or pulleys, but it is preferred that the lever is coupled to the handle portion by a push/pull rod. The lever may be coupled to a crank portion to which the push/pull rod is connected so that movement of the lever will cause the push/pull rod to move and cause movement of the handle portion. The lever preferably rotates about a lever axis which is substantially perpendicular to the steering axis. The lever may be coupled to the steering portion on each side of the steering portion and the lever may form a shell adapted to overlie a top surface of the stem.

The arrangement of the lever, push/pull rod and handle portion may include an over centre type latch arranged such that the latch is over centre when in the steering position and an initial retaining force must be overcome in order to actuate the lever.

It is preferred that the mechanism linking the lever to the handle portion is located in a hollow within steering portion so that it is protected from damage and provides a neater look to the stem.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figures 1, 2 & 3 show, in perspective, a stem in the steering position, half- open position and storage positions respectively; Figures 4, 5 & 6 show, in a cut-away view looking horizontally, a stem in the steering position, half-open position and storage positions respectively; Figures 7, 8 & 9 show, in a cut-away view looking vertically downwards, a stem in the steering position, half-open position and storage positions respectively; and Figure 10 shows a bicycle having a stem.

DETAILED DESCRIPTION

Referring initially to Figure 10 which shows a schematic view of a bicycle I which includes a frame 2, a rear wheel 4 coupled to the frame 2, a front fork 6 coupled to the frame 2 by a steering column 8 and a front wheel 10 coupled to the front fork 6 such that it can rotate about a front wheel axis 12. The bicycle I includes pedals 14 to drive the rear wheel 4 via a chain 16.

The bicycle includes handlebars 18 extending along a handlebar axis 16 coupled to the front fork 6 by a stem 20. The stem 20 comprises a handle end 22 coupled to the handlebars 18 and a steering end 24 coupled to the front fork 6 Figure 1 shows a detailed view of the stem 20 of Figure 10 in the steering position.

The stem 20 includes a steering portion 24 coupled to the front fork 6 and a handle portion 22 coupled to handlebars 18. The steering portion 24 extends transverse to the steering axis 28. The handlebars 18 extend along a handlebar axis 26 and the front fork 6 is mounted to the frame (not shown in this Figure) so that it can rotate about a steering axis 28. The handle portion 22 is coupled to a first end 52 of the steering portion 24 by a pivot 34 so that the handle portion can rotate about a pivot axis 36 with respect to the steering portion 24.

The stem 20 also includes a lever 30 coupled to the steering portion 24 so that it can rotate about a lever axis 32. As will be shown in more detail in later Figures, the lever 30 is coupled to a mechanism located within the steering portion 24 that causes the handle portion to pivot about the pivot axis 36 as the lever is rotated about the lever axis 32.

The handle portion 22 includes a clamp arrangement 38 to couple to the handlebars 18. It is preferred that the clamp arrangement comprises a hinged clamp portion which can be released at the non-hinged end from the handle portion so that the hinge can be opened and the handlebars accepted. The hinge can then be closed and the non-hinged end secured to the handle portion 22 and adjusted to clamp the handlebars 18 in place.

The steering portion 24 includes a clamp means 40 so that the stem can be clamped to the front fork 6. Other arrangement are possible and the stem may include an attachment portion that, in use, extends atong the steering axis and is coupled to the front forks by, for example, an expanding joint in a conventional way.

Figures 1-3 show the relative movement between the handle portion 22 and the steering portion 24 as the lever 30 is moved. Figure 1 shows the stem 20 in the steering position and Figure 3 shows the stem 20 in the storage position in which the handlebar axis 26 has been rotated about the pivot axis 36 by about 90 .

Figure 2 illustrates an intermediate position.

Figures 4-6 show a cut-away view looking from the side the stem 20 in the steering position, half-open position and storage positions respectively. Figures 7- 9 show a cut-away view looking from above the stem 20 in the steering position, half-open position and storage positions respectively.

It can be seen that the steering portion 24 has a hollow interior 42 within which is housed a mechanism for causing the handle portion 22 to move as the lever 30 is moved. The mechanism comprises a pull/push rod 44. Both ends of the push/pull rod 44 have spherical bearings 46 that allow full rotation about one axis, and some degree of rotation about the other two axes. The spherical bearing 46 at one end of the push/pull rod is aligned with the full rotation axis substantially perpendicular with the steering axis 28 and is coupled to a crank 48 which is in turn fixed to the lever 30 so that the crank rotates about the lever axis 32 as the lever 30 is moved.

The spherical bearing 46 at the other end of the push/pull rod is aligned with the full rotation axis substantially perpendicular with the handlebar axis 26 and is coupled to the handle portion 24 by an arm 50.

As shown in Figures 4-6 (or Figures 7-9), starting with Figure 4 (or Figure 7) in the steering position, as the lever 30 is moved the crank 48 rotates and causes the push/pull rod 44 to push the handle portion 22 away from a first end 52 of the steering portion 24 such that it pivots about the pivot axis 36 so that the handlebar axis is rotated with respect to the steering portion 24 and front wheel axis 12.

When the lever 30 has rotated by about 180 the handlebar axis has rotated by about 90 . It should be understood that by adjusting the shape of the crank 48, length of the push/pull rod 44 and position of the arm 50 the extent of rotation of the handle portion 22 can be adjusted.

If the movement of the lever 30 is reversed (so starting from the storage position in Figure 6) the push/pull rod 44 pulls the handle portion 22 towards the first end 52 of the steering portion 24 and the handle portion 22 rotates towards the steering position. In the steering position the crank 48 has rotated over-centre from the push/pull rod 44 so that a threshold force must be applied to the lever to cause the crank 48 to reach or move away from this position. This forms a lock for the stem in the steering position as a force in excess of the threshold force is required on the lever 30 to rotate the crank 48 back over the centre- line of the push/pull rod 44 in order to move the handle portion 24 to the storage position.

An additional safety catch could also be incorporated in the lever, to prevent it moving by accident due to shock or vibration. A latch mechanism that must be released before the lever can be moved would be suitable.

It should be understood that the invention has been described above by way of example only and that modifications in detail may be made without departing from the scope of the invention as described in the claims. 10-

Claims

1. A bicycle comprising a frame, a rear wheel coupled to the frame, a front fork coupled between a front wheel and handlebars, the handlebars extending along a handlebar axis, the front fork being pivotally coupled to the frame using a steering column such that the front forks can pivot about a steering axis to steer the front wheel, the front wheel being rotatable about a front wheel axis, the handlebars being coupled to the front fork by a stem, the stem comprising a handle portion and a steering portion, the steering portion being coupled to the front fork such that it extends transverse to the steering axis to a first end to which the handle portion is coupled, the handle portion coupling the handlebars to the steering portion wherein the handle portion of the stem is movable relative to the steering portion between a steering position and a storage position, in the steering position the handle portion is arranged adjacent the first end of the steering portion such that the handlebar axis is arranged substantially parallel with the front wheel axis, in the storage position the handle portion is rotated relative to the steering portion such that the handlebar axis is arranged at an angle of between 50 and 100 to the front wheel axis.

2. A bicycle as claimed in claim 1, in which the steering portion is pivotally coupled to the handle portion such that the handle portion is pivotable about a pivot axis with respect to the steering portion.

3. A bicycle as claimed in claim I or claim 2, in which the stem includes means for retaining the handle portion in the steering position.

4. A bicycle as claimed in claim 3, in which the stem includes a lever coupled to the steering portion and means for causing the handle portion to move between the steering position and the storage position as the lever is actuated.

5. A bicycle as claimed in claim 4, in which the means for causing the handle portion to move between the steering position and the storage position as the lever -Il - is actuated comprises a push/pull rod coupled between the lever and the handle portion such that as the lever is moved the push/pull rod forces the handle portion to move relative to the steering portion.

6. A bicycle as claimed in claim 5, in which the push/pull rod is coupled to the lever by an over centre mechanism arranged to retain the handle portion in the steering position such that a retaining force must be overcome by a user actuating the lever to move the handle portion from the steering position.

7. A bicycle as claimed in any of claims 4 to 6, in which the lever is arranged to cooperate with the handle portion in the steering position to retain handle portion in the steering position.

8. A bicycle as claimed in any preceding claim, in which the stem includes means by which the handle portion can be retained in the storage position.

9. A bicycle as claimed in claim 8, in which the handle portion is retained in the storage position by a ball and spring catch.

10. A stem for use in a bicycle as claimed in any preceding claim, the stem comprising a handle portion and a steering portion, the steering portion being for coupling to a steering column and extending to a first end to which the handle portion is coupled, the handle portion being for coupling the handlebars to the steering portion wherein the handle portion of the stem is movable relative to the steering portion between a steering position and a storage position.

11. A bicycle substantially as herein described with reference to, or as shown in, the accompanying drawings in Figure 1.

12. A stem substantially as herein described with reference to, or as shown in, the accompanying drawings.