DE9006510U1 - Stem for bicycle handlebars - Google Patents

Description

·· ·· ···* ·
· ·· · ■ ■■ D-8000 MUNICH 71
Hofbrunnstrasse 36
Phone: (089)79 9047
Telephone: 5-212877
Fax: (0 89) 7 91 52 56 de*a generic term H398 · · · ·
Weber & Home · ·
German patent attorneys
European Patent Attorneys Bicycles a stem for handlebars from bicycles Stem for handlebars from Mountain Bikes according to The invention relates to which, especially for of claim 1.

The positioning of the stem is crucial for the rider's safe posture. It also influences the handling, for example. For example, racing drivers prefer a seat position where the handlebars are positioned lower than the saddle in order to reduce air resistance due to the resulting posture. This seating position is achieved with long and ^flat stems.

However, when bicycles, especially mountain bikes, are used off-road, a seating position that depends on the terrain is desired in order to keep the strain on the arms and wrists as low as possible. For example, a shorter stem and a high saddle position are preferred when going uphill and the opposite position when going downhill.

In addition to absorbing the supporting forces of the upper body, the stem also has other tasks. It must be able to transmit the steering movement and the steering torque, position the handlebars in the right place and accommodate the support for the brake cable.

If the same bicycle or mountain bike was to be used for different purposes and/or for different riders and it was desired to have a

ff· ■·

In order to achieve the optimal body position, it was previously only possible to use stems with different dimensions. This meant that the entire stem had to be reassembled each time, and the handlebars, ?-"< as the actual handlebars, did not have to be replaced but also had to be reassembled.

With regard to the adjustability of the stem, a latent stem has become known whose stem cantilever tube is designed as a double tube, whereby the inclination of the stem cantilever tube in relation to the stem shaft tube can be changed via a joint connection with a quick-release fastener. The ends of the double stem cantilever tube are also provided with clamps in order to adjust the handlebar in relation to its longitudinal axis.

However, the disadvantage of this known stem is that the length of the stem cantilever tube cannot be changed in relation to the stem shaft tube. In addition, the stem is extremely complicated in terms of the adjustment options and the design of the stem cantilever tube as a double tube to absorb torque. This is reflected above all in its very high weight.

In another well-known adjustable stem, the design is comparatively simpler, but it still uses a stem cantilever tube that is designed as a double motor. The only adjustment option is the inclination of the stem cantilever tube, and there is no adjustment option with regard to the length of the stem cantilever tube. The respective positions are locked using screw clamps, which are time-consuming to operate. This well-known stem is also complicated in design and is made more difficult by the use of the stem designed as a double tube.

I·· ··· «It

&igr; < ■ i · · » ti

' I* Il ft ti I

cantilever tube and the clamping devices are relatively heavy.

The object of the present invention is to create a stem for handlebars of bicycles, in particular mountain bikes, in which the position of the handlebar, i.e. the height and inclination as well as the length of the stem, can be changed as desired via a simple, central mechanism, whereby reliable protection against unwanted adjustment should be provided in these handlebar positions.

The object is achieved in a generic front structure by the characterizing features of claim 1.

The clamping device of the invention is constructed as a joint clamp connection, by means of which a joint head clamp that holds the cantilever tube in a form-fitting and length-adjustable manner is arranged on the joint head base so that its inclination can be adjusted around an axis A. The joint clamp connection therefore has a dual function. This concerns the length adjustability of the cantilever tube in the joint head clamp, whereby this function is simultaneously combined with the inclination adjustability of the joint head clamp and thus of the cantilever tube using a single, central clamping mechanism.

The proposed solution now makes it possible to change not only the inclination but also the length of the stem using a central mechanism, namely either a clamping pin in the joint area between the stem shaft tube and the stem cantilever tube or an eccentric lock above this joint area. The desired position change of the handlebar can thus be carried out quickly and reliably with one hand movement. The division of the locking and clearance surfaces is chosen in such a way that even the smallest inclination changes are possible.

·: SI * &diams;·&igr; ·· ti

&bull; I · · ··■ *·&igr;&igr;

&bull; ··· · Uli · «I I

·· ■· t* f » ·· Il

The proposed solutions also make it possible to keep the weight of the stem low.

In an advantageous embodiment, the joint head clamp is designed with downwardly projecting legs 17 or webs, which interact via locking surfaces with complementary locking surfaces of the joint head base. In this case, the joint head base is accommodated in the lower part of the joint head clamp. The joint head clamp expediently has a slight pre-tension towards the outside, so that after slightly loosening a quick-release fastener in the transverse axis A, which lies transversely to the longitudinal axis of the bicycle, the length of the stem cantilever tube and/or its angle in relation to the bicycle frame can be changed.

In order to simplify the manufacture of the joint head clamp and the joint head fork, it is advantageously possible to form the locking surfaces from locking disks that lie opposite one another. The locking surfaces of the parts mentioned can therefore initially be flat.

The joint head clamp is designed in such a way that it has rounded webs with a central hole that are connected to the head of the clamp and are spaced apart from one another by a slot, with a locking disc being attached to the outer surfaces of the webs facing away from the slot. The usual manufacturing machines can therefore be used for the joint head clamp, since the locking discs are manufactured in a separate operation and are only attached to the designated surfaces after the joint head clamp has been completed.

This advantage also applies to the steering head fork, which then advantageously has rounded side parts with a central hole that accommodates the webs of the joint head clamp, with a locking disc being attached to the opposite inner surfaces of the side parts.

In a special embodiment, it is provided that the outer surfaces of the webs of the joint head clamp and the inner surfaces of the side parts of the joint head fork have recesses arranged around the circumference of the central bore for fastening the locking discs. With the help of these recesses, the locking discs can be attached easily and securely to the designated surfaces.

Another possibility for fastening the locking discs is that the webs have through holes arranged around the center hole. This makes it possible to pin the locking discs right up to the slot, and it is even conceivable that the two locking discs located on the webs of the joint head clamp are fastened using a single pin.

In order to ensure a secure locking effect, the locking disc is provided with a radial serration on one side surface, a central hole and additionally several holes running in the circumferential direction of the disc. The central hole serves to accommodate the bolt of the clamping pin and the additional holes are used to attach the locking disc to the surfaces provided for this purpose.

In an advantageous design, the locking discs are attached using mounting pins that fit into the corresponding recesses or holes in the joint head.

* t I
I t
■ I

clamp and the joint head fork or the corresponding holes in the locking disc. It is therefore possible to securely attach the locking discs using a normal pin connection.

So that after a change in the inclination of the stem, the supports for the brake cable and other devices on the handlebars do not have to be loosened and readjusted, it is advantageously provided that the handlebar-side end J of the stem shaft has a clamp connection with a quick release for holding the handlebars. This makes it possible to adjust the handlebars in a simple and quick manner in relation to their longitudinal axis and to adapt them to the selected inclination of the stem.

In a further embodiment of the invention, the inside of the clamp connection and the area of the handlebar covered by the clamp connection have serrations. This serration ensures that after the clamp connection is closed, the handlebar is reliably prevented from twisting around its longitudinal axis.

The quick release provided for the clamp connection is advantageously a clamping lever with an eccentric. It is therefore only necessary to turn the clamping lever to release the handlebars on the stem shaft on the one hand or to fix them on the other.

In a further embodiment , the clamping connection consists of a two-part sleeve, which has a guide in the slot area for receiving the clamping lever and in the other slot area devices for receiving a screw connection. By using a

The two-part sleeve ensures that the eccentric lock releases the sleeve far enough when loosened so that the handlebar can be easily turned, and when closed fits tightly enough against the handlebar to reliably prevent the handlebar from turning in an unwanted way.

In order to ensure that the torques acting on the stem cantilever tube via the handlebar can be absorbed easily and reliably in a one-piece design of the stem cantilever tube, it is advantageous for the stem cantilever tube to have a rectangular, preferably square, cross-section. The joint head clamp naturally has a corresponding cross-section. This design of the stem cantilever tube completely prevents twisting.

The same applies to another design of the cantilever tube, which in this case is rounded in the upper area and straight in the lower area. This results in a tunnel-like cross-section, in which the moment absorption is also guaranteed.

To avoid an undesirable longitudinal displacement of the cantilever tube in the tunnel-like cross-section, it is proposed to insert a trapezoidal wedge below the cantilever tube in the area of the joint head clamp, which can be moved against the cantilever tube when the clamping pin is tightened in order to support the clamping of the cantilever tube. Clamping is thus made possible not only by the joint head clamp, but also by the trapezoidal wedge used.

With regard to the alternative solution to the problem

■ ■ · ·

A further development of this invention proposes a task using a cylindrical fork stem head. The upper end of the isabelsea stem tube should have a serration on the lower surface of the lower clamping part. The serration used reliably prevents unwanted adjustment of the stem in terms of its inclination. A quick and tight R.L. connection in the joint area of the fork stem head is ensured if the pin has a thread onto which the eccentric lever can be screwed. By screwing on the eccentric lever, a certain basic tension can initially be provided in the fork stem head area in order to then achieve the final clamping tension by moving the eccentric lever.

The invention will be explained in more detail with reference to specific embodiments using the following figures. They show:

Fig. 1 is a side view of a stem according to the invention;

Fig. 2 is a rear view of the stem according to Fig. 1 without cantilever tube;

Fig. 3 a cross section through the joint head clamp according to Fig. 1;

Fig. 4 is a side view of the joint head clamp according to Fig. 3;

Fig. 5 is a rear view of a joint head fork;

Fig. 6 is a side view of the joint head fork according to Fig. 5;

Fig. 7 is a plan view of a toothed disk;

Fig. 8 a cross section through two opposing locking disks according to Fig. 7;

Fig. 9 a schematic spatial representation of a cantilever pipe connection ;

Fig. 10 a global spatial representation of the alternative agricultural connection;

Fig. II is a top view of the handlebar-side end of the cantilever tube according to Fig. 1;

Fig. 12 is a schematic spatial view of another front structure according to the invention and

. 13 an exploded view of essential parts according to Fig. 12 and

Fig. 14 is a vertical section through another alternative of the clamping device with a joint head base held by a joint head clamp.

Fig. 1 shows the side view of a stem 10 according to the invention. The joint head clamp 12 encompasses the stem cantilever tube 16 with its head 14. At the end of the fork shaft tube 18 is the joint head base, which is designed as a joint head fork 20, into which the webs 22 of the joint head clamp 12 engage. The joint head fork 20 and the webs 22 are connected to the stem via the bolt 24 of the clamping pin 26.

It ·■ · « Il ·· ··

&bull; I·· » 111. · It ·

t I · ··· It I · · · ■ I ·

··■> III· I··

&bull;ft ·· Il Il »I ··

- 10 -

connected to each other. At the handlebar end of the stem cantilever tube 16 there is a clamp connection 28 in the form of a quick-release fastener. A two-part sleeve 30 is provided for the clamp connection, which has a device at its ^upper end for receiving the clamping lever 32. At the lower end of the two-part sleeve there are devices for receiving screws 34 which connect the lower ends of the two-part sleeve 30 to each other. The two-part sleeve 30 is welded to the handlebar end of the stem cantilever tube 16.

In the rear view of the stem according to Fig. 2, the stem cantilever tube 16 has been omitted and only the joint head clamp 12 has been shown. For reasons of clarity, the locking surfaces or locking disks on the webs 22 of the joint head clamp 12 and the side parts 36 of the joint head fork 20 have also been omitted. It is easy to imagine that the locking devices are located on the one hand on the outer surfaces 38 of the webs 22 of the fork head clamp 12 and on the other hand on the inner surfaces 40 of the side parts 36 of the joint head fork 20. The bolt 24 of the clamping pin 26 ' penetrates - as shown - the side parts 36 of the joint head fork 26, the box devices and the webs of the joint head clamp 12. The bolt 24 is fixed on one side of the joint head clamp 12, whereas on the other side a clamping he*3l 32 is screwed onto the bolt 24.

In Fig. 3 a cross section through the joint head clamp 12 is shown. The central bores 42 through the side webs 22 for receiving the bolt 14 as well as the bores 44 for receiving pins for fastening the locking disks to the outer surfaces 38 of the webs 0 0.. can be clearly seen. Inner thread dor ritiTT'HHrihT'iinrref ¹ » 44 &Igr;&iacgr;&Lgr;&eegr;&eegr;&ogr;&eegr;j»iir>.h 1 aAi etX &Iacgr; rtH

- 11 -

Recesses are provided. Also shown is the slot 46, which is located between the webs 22 and also penetrates the lower area of the head 14 of the joint head shell 12. When the bolt 24 is tightened, the slot 46 narrows in order to securely fix the cantilever tube 16.

The arrangement of the locking disk 48 can be seen in the side view of the joint head clamp 12 in Fig. 4.

The web 22 is designed in its lower area to correspond to the disk-shaped locking disk* 48. Furthermore, this view clearly shows the arrangement of the additional holes 50 running in the circumferential direction of the locking disk, which coincide with the through holes 44 of the webs 22. The same applies to the central hole 52 of the locking disk 48.

Fig. 5 shows the rear view of the joint head fork 20. The side parts 36 with the inner surfaces 40 converge in the lower area, whereby the lower area is separated by a slot 54. This slot 54 ensures that the side parts 36 of the joint head fork 20 move towards each other when the bolt 24 is tightened so that a secure clamping can be achieved.

Fig. 6 shows the side view of the joint head fork 20, where it is shown that the upper area of the side parts 36 is rounded in accordance with the design of the locking disks. The central bore 56 serves to accommodate the bolt 24.

Fig. 7 shows a plan view of a locking surface designed as a locking disk 48 with a central bore 52 and the additional bores 50. In the upper area,

tet is the serration 58, which is present over the entire circumference of the locking disk 48 or at least over a substantial part of this circumference.

Fig. 8 shows a cross-section of two locking disks 48 lying opposite one another. When installed and in the clamping position, the individual teeth 60 of the serrations engage with one another. When adjusting the inclination and length of the cantilever tube 16, the clamping lever 32 is loosened to such an extent that the teeth 60 can just pass one another. The pins (not shown) for fastening the locking disks may only be fitted into the locking disk to such an extent that it does not protrude beyond the notch 62 between the teeth 60.

As a simpler alternative in terms of production technology, the locking disks 48 can, for example, be positively connected to the attachment surfaces of the joint head clamp or the joint head base 20 in the case of the design as a plastic part. For example, this could be done by locking the plastic part to the metal part or by sectorally flanging the plastic part through the metal.

In Fig. 9, the front cantilever tube 16 is shown in a schematic, spatial representation as it is fastened in the joint head clamp 12. The end 64 of the front cantilever tube 16 can be provided with a cotton or rubber sleeve, for example, to prevent injuries.

An alternative design of the cantilever tube is shown in a schematic spatial representation in Fig. 10. The cantilever tube 66 has a tunnel-like cross-section, i.e. it is rounded in the upper area.

t ·

- &igr;&igr;

I 1 I

- 13 -

det, flat in the lower area. A trapezoidal wedge 68 is used to secure the cantilever tube 66 against undesired longitudinal displacement, which is pressed upwards against the underside of the cantilever tube 66 via sliding jaws 69 when the clamping pin 70 is tightened. The underside of the cantilever tube 66 and the top of the trapezoidal wedge 68 can advantageously have a toothing. The locking surfaces or locking disks to prevent undesired inclination of the cantilever tube 66 are provided in the corresponding places.

Fig. 11 shows a top view of the handlebar-side end of the stem cantilever tube 16 according to Fig. 1. The clamping lever 32 is held in guides 72 which are spaced apart in order to be able to accommodate the eccentric 74 of the clamping lever 32. The guides 72 are welded to one half of the two-part sleeve on only one side of the slot 76. The stop piece of the eccentric 74 is attached accordingly to the other part of the sleeve 30.

Fig. 12 shows a schematic, three-dimensional view of another stem according to the invention. A stem cantilever tube 78 designed as a double tube is used, to the end of which the handlebar 80 is welded, although the arrangement of a clamp connection according to Fig. 11 is also conceivable in this area. The upper end of the fork shaft tube 82 is in this case designed as a cylindrical joint head base or fork shaft head 84. A two-part clamp 86 establishes the connection between the stem cantilever tube 78 and the fork shaft tube 82. The clamping takes place via an eccentric lock with an eccentric lever 88.

I4 ·
·
·
¹ I f

- 14 -

The internal structure of the stem is shown in an exploded view in Fig. 13. The cylindrical fork shaft head 84 has a serration 90 distributed over the upper circumferential surface. A corresponding serration 92 is provided in the lower region of the lower clamping part 94, with the clamping surface being shaped in accordance with the design of the fork shaft head 84. In the middle region of the fork shaft head 84, a pin 96 is provided in a transverse recess 98. The pin 96 is fixed in its lower region in the cavity ICO of the fork shaft head 84 by a correspondingly shaped counterpart. The pin 96 penetrates the lower clamping part 94 and the upper clamping part 102 in their middle areas between the recesses for the stem cantilever tube 78. The eccentric lever 88 is screwed onto the upper end of the pin 96 and, after reaching a certain basic tension, is turned over in order to apply the remaining clamping tension. The transverse recess 98 is designed to be so long that even the most extreme inclinations of the stem cantilever tube can be taken. The counterpart for securing the pin 96 in the cavity 100 of the fork shaft head 84 advantageously has a cross-sectional shape that corresponds to the curvature of the cavity 100 and is smooth so that the pin 96 can be easily adjusted.

In Fig. 14, a simple embodiment of the joint clamp connection 11 is shown in a schematic vertical section. The joint head clamp 12 has downwardly projecting legs 17, which are spaced apart from one another in the transverse direction by a free space 45. The fork shaft tube 18 projects into this free space from below. At the upper head end of the fork shaft tube 18, locking disks 48 are arranged on the outer surfaces facing the legs 17, which are connected to locking disks 48 via a complementary toothing.

which are attached to the inner surfaces of the legs 17.

A quick-release bolt (not shown) is received in a transverse bore 104 along the inclination axis A.

In the operating state, therefore, the front cantilever tube (not shown) is clamped in this clamping device 11 both longitudinally and torsionally, while at the same time the inclination lock is also adjusted via the toothed surface 49.

The fork shaft tube 18 has a blind hole 21 in which a screw bolt 23 is provided for wedge-clamping the handlebar stem to the lower fork tube of the bicycle.

The invention therefore creates a stem specifically for mountain bikes, which can be adjusted continuously or in stages, e.g. in steps of 3 to 5° in inclination and thus also in height, whereby the cantilever tube can also be adjusted in length * at the same time using the clamp closure via the clamp. The positive connection between the clamp and the stem cantilever tube ensures optimal transmission of torque and guided displacement, even backwards. The length adjustment path of the cantilever tube can be secured backwards by a spring-loaded stop, although it is possible to completely remove the cantilever tube including the handlebar and move it, e.g. by 90", to achieve a more convenient transport position. The locking discs of the central lock can be made of aluminum material for easy processing. The fork and the clamp are advantageously made of high-strength alloy steel.

Claims (16)

· I &Tgr;&Lgr;7»&EEgr;&bgr;&tgr; A- &Tgr;-&Tgr;&ogr;&iacgr;&Tgr;&Uacgr;&Iacgr;&igr; " "' D-8000 MUNICH WeJDer & ileim - l - Hofbrunnstrasse German Patent Attorneys Telephone: (089)799047 !European Patent AttorneysTelex: 5 - 2128 Fax: (0 89) 79152 H398 Expectations 1. Stem for handlebars of bicycles, irisbe&eneaere of Mourrtain bikes, with a clamping device between the steerer tube and the fork stem cantilever tube for adjusting and holding the stem cantilever tube; Alexsaas?, tz, characterized in that the clamping device (12,86) for the stem cantilever tube is arranged on a joint head base (20) so as to be adjustable in inclination via a clamping device (24, 26,32), in particular a clamping bolt, and that locking surfaces (48,49; 90,92) which can be brought into engagement with one another are provided between the clamping device (12,86) and the joint head base (20) for adjusting the inclination. 2. Stem according to claim 1, characterized, * ' that the locking surfaces are designed as toothed surfaces (48,49· 90,92). 3. Stem according to claim 1 or 2, characterized in that the locking surfaces are formed from opposing locking discs (48). 4. Stem according to one of claims 1 to 3, characterized in that the clamping device has a joint head clamp (12) with downwardly projecting webs (22,7.5), that the webs (22) are separated by a free space (45) or Bit* · · · · ft | &bull; 1 * · · · · · »S U · · I« t · ■■ I - 2 are spaced apart by a slot. 5. Stem according to claim 4, characterized in that the locking surfaces ^; -occje are provided on the surfaces of the webs <§ (22) facing the free space. 6. Stem according to one of claims 1 to 5, characterized in that the clamping device with its joint head clamp (12) surrounds the joint head base (20) on the outside or is arranged on the inside, and the clamping fastening has a clamping bolt which is provided approximately parallel to the handlebar and passes through the joint head clamp and the joint head base. 7. Stem according to one of claims 3 to 6, characterized in that the locking discs (48) are pinned and/or provided in a form-fitting manner on opposite surfaces of the joint head clamp (12) and the joint head base (20). 8. Stem according to one of claims 1 to 6, characterized in that the stem cantilever tube (16) is received in the joint head clamp (12) in a form-fitting and longitudinally displaceable manner. 9. Stem according to one of claims 1 to 7, characterized in that the stem cantilever tube (16) has a polygonal, in particular rectangular or square cross-section. 10. Stem according to one of claims 1 to f, characterized in that kB·· ■ a · &diams; · ■ &igr; · * · « that the cantilever tube (16) is rounded in the upper area and straight in the lower area. 11. Stem according to one of claims 1 to 10, characterized in that the stem cantilever tube (66) is held in the region of the joint arch (20) by a trapezoidal wedge (68) with a clamp fit. 12. Stem according to one of claims 1 to 11, characterized in that the stem cantilever tube (16, 66, 78) is arranged so as to be completely removable from the joint head clamp (12) at the front. 13. Stem according to one of claims 1 to 12, characterized in that the handlebar-side end of the stem cantilever tube (16) with quick release. 14. Stem according to claim 13, characterized in that the inside of the clamp connection (28) and the area of the handlebar covered by the clamp connection (28) have a serration. 15. Stem according to claim 13 or 14, characterized in that the quick release has a clamping lever (32) with eccentric (34). 16. Stem according to claim 1, characterized. that the front cantilever tube (78) is designed as a spaced double tube, the free ends of which are held in a two-part clamping tube (86), that the lower surface of the lower clamping part (94) has a circular arc-shaped recess, that the joint head base (84) is cylindrical and has a transverse recess (98), that a clamping screw (36) is provided both ways, and that the clamping screw (96) projects upwards through holes in the clamping parts (94,102), with an eccentric lever (88) being arranged at the end of the clamping screw (96). 17, stem according to claim 16, characterized in that the upper end of the fork head base and the lower surface of the lower clamping part (94) form serrations (90, 92) as locking surfaces.