DE29900493U1 - Adjustable stem handlebar for bicycles, especially sports bicycles - Google Patents

Description

ZENZ · HELBER · HOSBACH & PARTNERS

Patent Attorneys ■ European Patent Attorneys · 64673 Zwingenberg, Scheuergasse

Tel.: 06251-73008 · Fax: 06251-73156

Gerhard Lautenschläger, Backhausstrasse 29, 64395 Brensbach-Wersau

Adjustable stem handlebar for bicycles, especially

Sports bikes

Adjustable stem handlebar for bicycles, in particular bicycles for sports purposes, which on the one hand has an arm which is attached to the upper end of the handlebar stem which leads out from the steering head of the bicycle frame and is connected in alignment with the fork stem of the front wheel fork and on the other hand has an adjustable arm which accommodates the handlebar to be grasped by the rider.

Certain sports bikes, such as mountain bikes, trekking bikes and road and off-road racing machines, are equipped with so-called stem handlebars, in which the actual handlebars, which are gripped by the rider at the outer end, are clamped in a stem that protrudes forwards from the axis of the fork shaft of the front wheel fork. The purpose of this arrangement is to force the user of the bike into a deeply bent position when gripping the handlebars held in the handlebars as intended. This - compared to the normal upright

sitting position on a touring bike - results in a significant reduction in air resistance. However, this extremely crouched position is not the most comfortable in the long run - at least for untrained people - so it is not unusual to see riders of a sports bike temporarily adopt an upright sitting position and then grip the handlebars in their horizontal, transverse section adjacent to the stem in order to relieve the muscles strained when the rider bends their upper body. However, if obstacles suddenly appear, braking is then only possible with a delay because the brake levers on the handlebars are attached in such a way that immediate and ergonomic operation with full force is only possible if the handlebars are gripped in the outer sections in the intended crouched position.

There is therefore definitely a need for a handlebar that can be adjusted from the usual low-drag position, which forces the rider into a crouched position, to a position in which the rider can adopt an upright posture that relieves the strain on the back muscles.

Stem sports handlebars are known in which the stem that clamps the handlebar is designed as a separate component that can be adjusted relative to the part of the handlebar provided on the handlebar shaft as an extension of the front fork's axis. However, with these known adjustable stem handlebars, adjustment is only possible with tools, which are required - e.g. to release the clamping of the stem in the low position and to re-lock the handlebar after adjustment in the raised position. The handlebars cannot therefore be adjusted while riding. When adjusting the height, the clamping of the stem on the essentially vertical axis extension of the bicycle fork is usually loosened, whereupon the now separate component

formed stem is pivoted up around a transverse axis and then fixed again. In doing so, the actual handlebar, which is clamped to the front free end of the stem, is also pivoted upwards on a circular arc, whereby the operating levers for the bicycle brakes, which were originally in the ergonomically correct position for the lowered handlebars, are also in a pivoted up position in which they are practically not grippable enough to apply a really effective braking force. This means that with the known height-adjustable stem handlebars, the clamp of the handlebar at the free end of the stem must also be loosened.
and then the handlebar after the height adjustment
into the position suitable for operating the brake lever and then clamped again. It is

It is therefore clear that the conversion of the well-known height-adjustable stem handlebars requires a longer interruption of driving, so that such a conversion is under no circumstances an option during a competition or even when several riders are out together.

In contrast, the invention is based on the task of developing the known handlebars for sports bicycles in such a way that the height of the handlebar can be changed without difficulty while riding, whereby an adjustment of the handlebar to correct the position of the
Brake operating lever is not required.

Starting from a handlebar of the type mentioned at the beginning, this object is achieved according to the invention in that the boom forming part of the stem has a fastening head for the handlebar shaft at the frame-side end and
has a mounting head for the handlebar, which
by two spaced apart, each at its ends perpendicular to the axis of the handlebar shaft and parallel
to the axis of the handlebar in its mounting area in the
Mounting head extending axes pivotable hinged

Articulated levers are connected, and that manually operable locking means are provided which can be selectively engaged and disengaged and which, in the engaged position, secure the articulated levers against pivoting about their axes relative to the fastening and holding head. The four-bar mechanism formed by the fastening and holding head and the articulated levers pivotally connected to these heads allows the position of the holding head of the handlebar to be changed from the lowered position which forces the driver to bend down deeply, to a position which is raised in comparison and additionally offset backwards against the direction of travel. In this raised and offset position, the handlebar can be grasped by the driver in a more comfortable upright position which relieves the strain on the back muscles. The pivoting position of the boom selected by the driver can then be fixed using the locking means provided. The articulated levers are designed as profiles - preferably metal - each with an essentially U-shaped cross-section, which are arranged with the open mouth of their U-cross-section facing each other. By designing the articulated levers as U-profiles, a significant weight saving is achieved - compared to a solid design - which is particularly desirable for sporty bicycles.

The side cheeks of the articulated levers, which protrude from the web wall to the other articulated lever, are designed so that their front edges lie flush against one another when the boom is in the fully lowered position. In this lowered position, which is to be regarded as the normal position when the associated bicycle is used as a piece of sports equipment, the boom then looks like a single, compact component.

In a preferred embodiment of the invention, the locking means comprise at least one on one of the articulated levers

arranged, spring-loaded locking element which is urged into engagement with a locking receptacle provided on the other articulated lever and which can be pushed back from the engagement position with the locking receptacle against the spring preload.

It is recommended that at least one locking element be mounted in a receptacle in a projection protruding from the inside of the web wall of one of the articulated levers, parallel to the pivot axes of the articulated levers, and that it be preloaded by the spring in the direction of one of the cheeks of the other articulated lever, wherein in the area of the cheek of the other articulated lever opposite the locking element when the boom is pivoted, a slot-like opening is provided in the cheek, which forms the locking receptacle and in which the associated free end of the locking element engages.

In order to enable the locking element to be operated as easily as possible, a further development according to the invention provides that a short shaft of reduced diameter is attached to the front side of the locking element, which penetrates the opening in the cheek of the articulated lever, and at the free end of which an actuating handle is provided, which enables the locking element to be moved against the spring preload by pressure exerted on its outward-facing actuating surface. The actuating handle located in front of the outside of the cheeks can therefore be grasped and operated by the driver - if necessary even while driving - and the boom can then be swiveled without having to change hands with the same hand.

In a preferred embodiment of the invention, the locking means have two locking elements which are fixed in opposite directions.

·

The system has pre-tensioned locking elements, each of which has a separate locking receptacle in the opposite cheek. This locking by two separate locking elements, which must be operated in opposite directions to unlock, i.e. by pressing on their respective actuating handles, represents a safety feature. Even if one of the locking elements is accidentally operated by the driver himself or due to other circumstances, an unintentional unlocking and adjustment of the boom and thus the position of the handlebar, which would surprise the driver, is ruled out.

The slot-like opening(s) forming the locking receptacle(s) are expediently provided with a number of locking openings spaced apart from one another and larger than the width of the opening, with the locking element(s) then being shaped to complement the locking openings in their end area facing the respective opening. This makes it possible to pivot and fix the boom in a number of pivot positions of the boom corresponding to the number of locking openings, i.e. the boom can be adjusted in stages from the fully lowered front position to the raised, retracted position of the handlebar mounting head.

A continuous adjustment can be achieved by a design in which the opening(s) and the free end(s) of the respective associated locking element have complementary conical engagement surfaces. Instead of the positive engagement of the free ends of the locking elements in the locking opening, a force-locking clamping engagement of the locking elements in the opening is achieved here. By selecting the appropriate spring preload and the force connection between the conical engagement surfaces, this design also ensures reliable adjustment that the driver can easily carry out while driving.

A locking mechanism that can be disabled for the purpose of pivoting the boom is possible.

In a currently preferred embodiment of the invention, the projection which slidably receives the at least one locking element protrudes from the inside of the web wall of the lower articulated lever between the lateral cheeks of the upper articulated lever, with the slot-like opening(s) forming the locking receptacle(s) then being provided in the lateral cheek(s) of the upper articulated lever. The projection can either be provided integrally on the lower articulated lever or can be a separately manufactured component which is fastened to the inside of the web wall of the lower articulated lever.

The distance between the pivot axes of the two articulated levers is preferably chosen to be essentially the same, as is the distance between the pivot axes of the operating head and the mounting head. The four-bar mechanism of the boom then forms a parallelogram guide for the handlebar, which ensures that the position of the brake operating levers at the outer ends of the handlebar does not change when the boom is pivoted. As an alternative to this, if desired, by changing the distances between the pivot axes of the articulated levers or the fastening and mounting heads, a kinematics that deviates from the pure parallelogram guide can be achieved, which results in a corresponding change in the position of the brake operating levers of the handlebar in the raised position, which, with regard to ergonomic operation, takes into account the change in the alignment of the driver's arms and hands in the upright position of his torso.

The invention is explained in more detail in the following description of an embodiment in conjunction with the drawing, which shows:

Fig. 1 is a partially sectioned side view of a stem of a bicycle handlebar designed as a pivoting boom in a first lowered pivoting end position,

Fig. 2 is a view corresponding to Fig. 1, in which the boom is in the second raised swivel end position;

Fig. 3 is a sectional view taken in the direction of arrows 3-3 in Fig. 1;

Fig. 4 is a view of one of the articulated levers forming two parts of the boom of the handlebar according to the invention, viewed from below;

Fig. 5 is a sectional view of the articulated lever, seen in the direction of arrows 5-5 in Fig. 4;

Fig. 6 is a sectional view of the second articulated lever forming part of the boom of the handlebar according to the invention, in a sectional view, in the longitudinal center plane illustrated by the arrows 6-6 in Fig. 7;

Fig. 7 is a view of the second articulated lever, seen in the direction of arrow 7 in Fig. 6;

Fig. 8 is a side view of part of the boom of the handlebar according to the invention

forming fastening head for the
handlebar;

Fig. 9 a front view of the fastening head,
seen in the direction of arrow 9 in Fig. 8;

Fig. 10 a sectional view through a part
of the boom of the inventive
Handlebar forming mounting head in
which is indicated in Fig. 9 by arrows 10-10
illustrated cutting plane;

Fig. 11 is a view of the mounting head, seen in the direction of arrow 11 in
fig.10,

Fig. 12 is a view of the front side of the boom of the inventive

Locking element that locks the handlebar in selectable swivel positions;

Fig. 13 is a sectional view taken in the direction of arrows 13-13 in Fig. 12;

Fig. 14 a side view of an actuating

handle for the locking element according to Fig. 12 and 13;

Fig. 15 is a plan view of the locking element shown in Fig. 14;

Fig. 16 a for pre-tensioning the locking element

according to Fig. 12 and 13, the coil spring serving in the locking position in side view; and

«

Fig. 17 is a side view of a pivoting lever provided for pivotably supporting the articulated levers on the fastening head according to Figs. 10 and 11 and on the mounting head according to Figs. 8 and 9,

End of a threaded pin provided with a bearing pin.

1 and 2 show a stem of a bicycle handlebar according to the invention, designed as a pivotable arm 10, preferably for sporty bicycles. The arm 10 is attached to a handlebar shaft 12, which in turn can be connected in a rotationally fixed manner to a shaft of the front wheel fork that is rotatably mounted in the steering head of a bicycle frame, by a fastening head 14 - described in more detail below in connection with Figs. 10 and 11 - in a manner known per se by means of a clamp connection. The handlebar 16, which is to be grasped by the rider and is provided in its two end areas (not shown) with brake actuation levers for a front wheel and a rear wheel brake, is held - also clamped - in a mounting head 18 spaced apart from the fastening head 14. The fastening head 14 and the holder head 18 are connected to one another by an upper articulated lever 20 and a lower articulated lever 22. Both articulated levers are designed as metallic profiles with a substantially U-shaped cross section, the web wall 24 of the upper articulated lever 20 (Fig. 4 and 5) closing off the boom 10 at the top and the cheeks 26 adjoining the web wall 24 are directed downwards towards the lower articulated lever 22.

The web wall 2 8 of the lower articulated lever 22 (Fig. 6 and 7), on the other hand, closes the underside of the boom 10 and its lateral cheeks 3 0 are directed upwards in the direction of the upper articulated lever 20.

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In the cheeks 26 of the upper articulated lever 20 as well as in the cheeks 30 of the lower articulated lever 22, bearing bores 32 and 34 are provided in the end areas for bearing pins projecting laterally from the fastening head 14 or the holder head 18, respectively, which are each arranged at the outer end of a threaded pin 38 (Fig. 17) which is screwed into an associated threaded bore 40 or 42 in the fastening head 14 or in the holder head 16. The articulated levers 20 and 22 are thus each pivotably connected to the fastening head 14 and the holder head 18, so that the boom 10 as a whole forms a four-bar mechanism. The mounting head 18 which clamps the handlebar 16 can therefore be pivoted relative to the fastening head 14 which is clamped onto the handlebar shaft 12 between the end positions shown in Fig. 1 and 2, the articulated levers 20 and 22 representing a parallelogram guide which, in the special case in which the distance between the bearing bores of the upper articulated lever 20 and the bearing bores 34 of the lower articulated lever 22 on the one hand and the distances between the threaded bores 40 of the fastening head and 42 of the mounting head 18 are the same, ensures that the relative alignment of the ends of the handlebar 16 held clamped in the mounting head does not change with respect to the alignment to the driver's hands. This means that when the boom is pivoted from the front lowered position (Fig. 1) to the raised and retracted position (Fig. 2), the steering rod does not change its position in the sense of a rotation about its longitudinal central axis.

This means that the brake operating levers provided at the ends of the handlebar also retain their relative position and can be gripped in the same way in all swivel positions of the boom. By slightly changing the distances between the bearing points of the articulated levers on the fastening and/or mounting head, the kinematics of the four-bar mechanism can also be changed in such a way that the desired small changes can still be achieved.

·

·

Changes in the rotational position of the handlebar 16 in the different boom pivot positions are taken into account to take into account the change in the posture of the driver's torso when grasping the handlebar. 5

The articulated levers 20 and 22 are shaped or limited in such a way that they rest against one another in the lowered boom position shown in Fig. 1. In this lowered position, the boom is also closed laterally in a visually advantageous manner and gives the impression of a one-piece component.

From the inside of the web wall 38 of the lower articulated lever 22, a tapering projection 40 projects approximately centrally between the cheeks 26 of the articulated lever 20, in the upper end of which a transverse bore 42 is provided, in which two essentially cylindrical locking elements 48 are slidably mounted, each urged outwards towards the associated cheek 26 of the upper articulated lever 20 by a helical spring 46 (Fig. 16), one of which is shown in Figs. 12 and 13. To accommodate the ends of the helical spring 46, blind holes 50 are drilled into the mutually facing end faces of the locking elements 48, and a threaded hole 52 of smaller diameter is made from the outward-facing opposite end faces, into which the threaded shaft 54 of an actuating handle 58 provided with a circularly delimited pressure plate 56 at its outer end can be screwed. Between the threaded section 54 and the pressure plate 56, a threadless shaft section 60 is provided, which penetrates the arcuate slot-shaped opening 62, best seen in Fig. 5, in the associated cheek 26 of the upper articulated lever 20.

These slot-like openings 62 are provided with a number of spaced apart, enlarged-diameter locking openings 64, the diameter of which is so

is selected so that a section 66 of the locking elements which is reduced in diameter in the cheek-side end area of the locking elements can engage with them. In particular, it can be seen in Fig. 3 how the locking elements 48 are forced into locking engagement with the locking openings by the coil spring 46 and thus lock the two articulated levers 20 and 22 against pivoting. Furthermore, it can be seen that when opposing pressure is exerted on the two outer surfaces of the pressure plates 56, the actuating handles 58 can be pushed back into the bore 52 so that the locking engagement of the locking elements 48 with the locking openings 64 is canceled. If a force is then exerted on the actuating handles in the corresponding direction in the unlocked state, the boom is pivoted in the desired direction. The boom can therefore be unlocked and pivoted with one hand without complicated manipulation, i.e. it can be carried out by the driver while driving.

The clamping attachment of the attachment head 14 on the handlebar shaft 12 as well as the clamping mount of the handlebar 16 in the mount head 18 need not be described in detail here, since they basically correspond to the clamp mounts of a non-pivoting boom on the handlebar shaft or handlebar. For this purpose, the attachment head 14 is slotted diametrically opposite from opposite sides over part of its length and can therefore be reduced in diameter by suitable transverse clamping screws so that the clamping attachment on the handlebar shaft 12 is achieved with the required load capacity. The mount head 18, on the other hand, is only provided with a slot running across its entire width and here too the clamping mount of the handlebar 16 can be ensured by changing the diameter of the mount for the handlebar by tightening clamping screws.

It is clear that within the scope of the inventive concept, modifications and further developments of the described embodiment can be implemented. For example, the locking device described can be modified in such a way that instead of a positive locking of the boom in a defined number of swivel positions, a continuous adjustment and locking in any swivel position is possible by a force-fitting design of the locking device.
10

Claims (12)

1. Adjustable stem handlebar for bicycles, in particular bicycles for sports purposes, which on the one hand has an arm (10) which is fastened to the upper end of the handlebar shaft ( 12 ) which extends out of the steering head of the bicycle frame and is connected in alignment with the fork shaft of the front wheel fork, and on the other hand adjustably accommodates the handlebar ( 16 ) to be gripped by the driver, characterized in that the arm ( 10 ) has a fastening head ( 14 ) for the handlebar shaft ( 12 ) at the end on the frame side and a mounting head ( 18 ) for the handlebar ( 16 ) at the other end, which is pivotably connected by two articulated levers (20; 22 ) which are spaced apart from one another and are each pivotably connected at their ends about axes running at right angles to the axis of the handlebar shaft (12) and parallel to the axis of the handlebar ( 16 ) in the fastening area of the latter in the mounting head ( 18 ) . are connected, and that manually operable locking means are provided which can be selectively engaged and disengaged and which, in the engaged position, fix the articulated levers ( 20 ; 22 ) against pivoting about their axes relative to the fastening and holding head ( 14 ; 18 ). 2. Stem handlebar according to claim 1, characterized in that the articulated levers ( 20 ; 22 ) are designed as profiles each having a substantially U-shaped cross section, which are arranged with the open mouth of their U-cross section facing each other. 3. Stem handlebar according to claim 2, characterized in that the lateral cheeks ( 26 ; 30 ) of the articulated levers ( 20 ; 22 ) projecting from the web wall ( 24 ; 28 ) to the other articulated lever are shaped such that their front edges lie flush against one another in the fully lowered position of the boom ( 10 ). 4. Stem handlebar according to one of claims 1 to 3, characterized in that the locking means have at least one locking element ( 48 ) arranged on one of the articulated levers ( 20 ; 22 ), resiliently urged into engagement with a locking receptacle provided on the other articulated lever ( 20 ; 22 ), which can be pushed back against the spring preload from the engagement position with the locking receptacle. 5. Stem handlebar according to claim 4, characterized in that the at least one locking element ( 48 ) is mounted parallel to the pivot axes of the articulated levers ( 20 ; 22 ) in a receptacle ( 42 ) in a projection ( 40 ) protruding from the inside of the web wall ( 28 ) of one of the articulated levers ( 22 ) and is prestressed by the spring preload in the direction of one of the cheeks ( 26 ) of the other articulated lever ( 20 ), and that in the area of the cheek ( 26 ) of the other articulated lever ( 20 ) opposite the locking element ( 48 ) when the boom ( 10 ) is pivoted, a slot-like opening ( 62 ) is provided in the cheek ( 26 ) which forms the locking receptacle and which is designed in a manner corresponding to the path traveled by the locking element when the boom pivots, into which the associated free end of the locking element ( 48 ) engages. 6. Stem handlebar according to claim 5, characterized in that a short shaft ( 60) of reduced diameter passing through the opening (62 ) in the cheek ( 26 ) of the articulated lever ( 20 ) is attached to the front side of the locking element ( 48 ), at the free end of which an actuating handle (pressure plate 56 ) is provided, which enables a displacement of the locking element ( 48 ) against the spring preload by a pressure exerted on its outwardly facing actuating surface. 7. Stem handlebar according to one of claims 4 to 6, characterized in that the locking means have two locking elements ( 48 ) which are spring-loaded in opposite directions and each of which is assigned a separate locking receptacle ( 62 ; 64 ). 8. Stem handlebar according to claim 6 or 7, characterized in that the slot-like opening(s) ( 62 ) forming the locking receptacle(s) are provided with a number of locking openings ( 64 ) spaced apart from one another and enlarged compared to the width of the opening ( 62 ), and that the locking element ( 48 ) or the locking elements ( 48 ) are shaped in their end region facing the respective opening to complement the locking openings ( 64 ). 9. Stem handlebar according to claim 5, characterized in that the opening(s) and the free end(s) of the respectively associated locking element have complementary conical engagement surfaces. 10. Stem handlebar according to one of claims 5 to 9, characterized in that the projection ( 40 ) slidably receiving the at least one locking element ( 48 ) protrudes from the inside of the web wall ( 28 ) of the lower articulated lever ( 22 ) between the lateral cheeks ( 26 ) of the upper articulated lever ( 20 ), and that the slot-like opening(s) ( 62 ) forming the locking receptacle(s) is/are provided in the lateral cheek(s) ( 26 ) of the upper articulated lever ( 20 ). 11. Stem handlebar according to one of claims 1 to 10, characterized in that the distance between the pivot axes of the two articulated levers ( 20 ; 22 ) is substantially equal. 12. Stem handlebar according to one of claims 1 to 11, characterized in that the distance between the pivot axes of the actuating head ( 14 ) and the mounting head ( 18 ) is substantially equal.