Bicycle Fork and Bicycle Fork System

Abstract

A bicycle fork including two fork legs connected with each other via a fork bridge. The fork bridge is connected with a steer tube. For a simpler arrangement of shift cables, hydraulic lines, cables and the like, the steer tube includes at least one flattening extending in the longitudinal direction of the steer shaft.

Claims

1. A bicycle fork comprising: two fork legs connected with one another via a fork bridge, and a steer tube connected with said fork bridge, the steer tube comprising at least one flattening extending in the longitudinal direction of the steer tube.

2. The bicycle fork according to claim 1, wherein said steer tube comprises two flattenings extending in the longitudinal direction of the steer tube.

3. The bicycle fork according to claim 1, wherein a front side of the steer tube directed in a traveling direction is convexly curved, in particular formed in a circular arc shape.

4. The bicycle fork according to claim 1, wherein a front part of the steer tube directed in a traveling direction, in particular an upper part of the steer tube is formed in a ring segment shape, wherein, preferably, the ring segment-shaped part extends over at least 90°, in particular at least 120° and, as is particularly preferred, at least 150°.

5. The bicycle fork according to claim 4, wherein the ring segment-shaped part extends over an angle of less than 270°, in particular less than 230° and, as is particularly preferred, less than 200°.

6. The bicycle fork according to claim 1, wherein a rear side of the steer tube directed opposite to a traveling direction is convexly curved, in particular formed in a circular arc shape, wherein, preferably, the rear side is arranged opposite a front side and both the front side and the rear side have the same circular center.

7. The bicycle fork according to claim 1, wherein a rear part of the steer tube directed opposite to a traveling direction is formed in a ring segment shape, wherein, preferably, the rear part extends over at least 20°, in particular at least 30° and, as is particularly preferred, at least 40°.

8. The bicycle fork according to claim 7, wherein the ring rear part extends over an angle of less than 120°, in particular less than 90° and, as is particularly preferred, less than 70°.

9. The bicycle fork according to claim 2, wherein the two flattenings are arranged between a front part and a rear part and the two flattenings extend from an upper end of the steer tube towards the fork bridge, wherein, preferably, the two flattenings extend over at least 50%, preferably over at least 75% of the total length of the steer tube.

10. The bicycle fork according to claim 1, the steer tube comprising a cylindrical lower part facing the fork bridge, which cylindrical lower part extends preferably from the fork bridge over at least 20 mm, in particular at least 45 mm, and is preferably shorter than 70 mm, in particular shorter than 50 mm.

11. The bicycle fork according to claim 10, wherein the circular cylindrical part is offset, in particular not coaxial, with respect to the upper part of the steer tube having the in particular two flattenings.

12. The bicycle fork according to claim 10, wherein the circular cylindrical part has a larger outer diameter than the upper part of the steer tube having the in particular two flattenings.

13. The bicycle fork according to claim 1, further comprising a bearing seat for a lower steering bearing on an upper side of the fork bridge.

14. A bicycle fork system comprising a bicycle fork according to claim 1, and a cover cap connected with an upper region of the steer tube.

15. The bicycle fork system according to claim 14 the cover cap comprising a central opening, the contour of which corresponds to the outer contour of the steer tube in the region of the in particular two flattenings, wherein, preferably, the opening has a respective indentation in the region of the in particular two flattenings.

16. The bicycle fork system according to claim 15, the cover cap further comprising at least one lead-through opening for wires, cables, hydraulic lines and the like, wherein the lead-through opening is preferably arranged in the region of the indentation.

17. The bicycle fork system according to claim 16, the lead-through opening further comprising a sealing element.

18. The bicycle fork system according to claim 14, further comprising a circumferential, in particular annular seal on a lower side of the cover cap.

19. The bicycle fork system according to claim 14, the cover cap further comprising a holding element for fixing the cover cap to the steer tube, wherein, in the mounted state, the holding element preferably comprising a clamping element clampingly pressing against an outer side of the steer tube using a fixing element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In the following, the disclosure is described in more detail by means of a preferred embodiment with reference to the accompanying drawings.

[0025] In the drawings:

[0026] FIG. 1 is a schematic perspective view of a bicycle fork,

[0027] FIG. 2 is a schematic top plan view of the bicycle fork illustrated in FIG. 1,

[0028] FIG. 3 is a schematic perspective top plan view of a cover cap,

[0029] FIG. 4 is a schematic perspective view of the cover cap shown in FIG. 3, seen from below and

[0030] FIG. 5 is a schematic side view of a head tube of a bicycle frame together with a handlebar stem in the mounted state.

DETAILED DESCRIPTION

[0031] A bicycle fork comprises two fork legs 10 connected with each other via a fork bridge 12. The fork bridge 12 is connected with a steer tube 14. According to the disclosure, the steer tube 14 has an upper part 16, a lower part 18, as well as a connecting part 20.

[0032] In the embodiment illustrated, the upper part 16 has a circular basic shape in cross section, wherein the shape has a non-circular cross section due to two flattenings. The two flattenings 22 that extend in the longitudinal direction 24 of the steer tube 14, have a substantially flat upper side and are formed in the manner of a chord in a circular cross section. Seen in the traveling direction 26, the upper part 16 of the steer tube 14 has a front part 28, the front side 30 of which is convexly curved, the front side being a circular arc-shaped front side in the illustrated embodiment. As can be seen in particular in FIG. 2, the front part 28 is formed in a circular ring segment shape. Starting clockwise from the left flattening 22 in FIG. 1 to the right flattening 22, the front part 28 extends over an angle of about 180°±10°.

[0033] Opposite the front side 30, the steer tube has a rear side 32 which is also convexly curved and formed in a circular arc shape in the embodiment illustrated. The front side 30, as well as the rear side 32 have the same center or are located on the same circle line. A rear part 34 forming the rear side 32 is located opposite the front part 28. The rear part 34 is also formed in a circular ring segment shape and has the same center as the front circular ring-shaped segment 28. In the embodiment illustrated, the rear part 34 extends counterclockwise from the left flattening in FIG. 2 to the right flattening in FIG. 2 over about 30°±10°.

[0034] Between the two ring segment-shaped parts 28 and 34, the two flattenings 22 are arranged which in the embodiment illustrated are formed as planar straight walls, so that in the upper part, the steer tube 14 has a closed contour in the circumferential direction.

[0035] The two flattenings 22 shown in the embodiment illustrated extend from an upper end 36 of the steer tube 14 over at least ⅔ of the length of the steer tube 14 toward the fork bridge 12. The lower part 18 is formed at the fork bridge-side end of the steer tube 14. The same has a cylindrical cross section. Here, the outer diameter of the lower part 18 is larger than the outer diameter of the upper part 16 of the steer tube 14. The intermediate part 20 serves for connecting the upper part 16 and the lower part 18 and aligns the different outer contours of the two parts 16, 18.

[0036] The upper part 16 of the steer tube 14 having the flattenings is not coaxial with the cylindrical part 18, but is arranged offset in the traveling direction 26. As is evident in particular from FIG. 2, a longitudinal axis 38 of the upper part 16 of the steer tube is offset forward in the traveling direction 26 with respect to a longitudinal axis 40 of the lower cylindrical part 18 of the steer tube. On the longitudinal axes 38, 40, also the centers of the ring segment-shaped elements 28, 34 or the cylindrical lower part 18, respectively.

[0037] As is evident in particular from FIG. 2, the design of the upper part 16 of the steer tube creates a cavity in the region of the flattenings 22, in which shift cables, hydraulic lines, wires and the like can be arranged.

[0038] Depending on the size of the bicycle frame and thus depending on the length of a head tube 42 (FIG. 5) of the bicycle frame in which the steer tube 14 is arranged, an upper end of the steer tube 14 protrudes. In the mounted state, a cover cap 44 is arranged above the head tube 42 of the bicycle frame. The cover cap 44 is illustrated in detail in FIGS. 3 and 4. The cover cap 44 has an opening 46 formed as a lead-through opening. In the mounted state, the upper part 16 of the steer tube 14 is arranged in the opening 46. An inner contour of the opening 46 corresponds to the outer contour of the upper part 16 of the steer tube 14. As such, the opening 46 has two opposite flat sides 48. In the mounted state, the flat sides 48 are parallel to the flattenings 22. Further, the opening 46 comprises a circular segment-shaped section 50 which in the mounted state, extends parallel to the front side 30. A clamping element 52 is arranged opposite the inner side 50 of the opening 46, the inner side 54 thereof being concavely curved. In the mounted state, the inner side 54 of the clamping element 52 is pressed against the rear side 32. For this purpose, the clamping element 52 is connected with a screw 56 to form a holding element. The screw 56 engaging the thread serves for displacing the clamping element 54 for a clamping fixing on the rear side 32 of the steer tube.

[0039] For forming the flat side walls 48, with respect to a usually round opening, the cover cap 44 has indentations 58. Lead-through openings 60 are provided in particular in the region of these two indentations 58. In the embodiment illustrated, each lead-through opening 60 serves for leading through two wires, cables, hydraulic lines or the like. A respective sealing element 62 is arranged in each of the lead-through openings 60 in order to avoid the ingress of water or humidity.

[0040] Further, an annular sealing element 66 is arranged on a lower side 64. In the mounted state (FIG. 5), the sealing element 66 abuts on an upper side of the head tube 42, so that the ingress of humidity into the head tube 42 is avoided in this region, too.

[0041] For mounting, the steer tube 14 is inserted into the head tube 42 of the bicycle frame (FIG. 5) from below. Here, a lower bearing is arranged in the steer tube 14, which bearing rests on an annular surface 68 (FIG. 1) in the mounted state. As is typical, a bearing is arranged also in the upper region of the head tube 42. A com-pression ring is arranged above the bearing. The same is designed such that it is enlarged on a side that is a rear side with respect to the traveling direction 26. Thereby, the offset between the upper part 16 of the steer tube 14 and the lower part 18 of the steer tube 14 is compensated for, since the two bearings have to be arranged coaxially one relative to the other.

[0042] In the next step, the bearings are pretensioned, for example via a conventional tensioning means arranged inside the steer tube and supported on the upper side of the steer tube. As soon as the bearings are pretensioned, the cover cap 44 can be fixed using the holding element 52, 56 by clampingly connecting the same with the upper part 16 of the steer tube 14. Since the pretensioning of the bearings is thereby main-tained, a handlebar stem 70 (FIG. 5) can, for example, be disassembled for transport together with the handlebar stem, without a new adjustment of the bearings having to be performed.

[0043] During assembly, wires, shift cables, hydraulic lines and the like can be mounted in a simple manner. For this purpose, the cables 72 are passed through the lead-through openings 60 in the cover cap 44 and then extend along the flattenings 22 downward in the direction of the fork bridge 12. Depending on the cables etc., these may then be lead into a top tube 74 of the bicycle frame or also into a downtube of the bicycle frame, not illustrated to be led to the gear system, the rear wheel brake or the like. For connection with a front wheel brake, a hydraulic line or another cable can be led along the flattening 22, which is the right flattening with respect to the traveling direction 26 in FIG. 2, and then be led into the inside of the steer tube 14 through an opening 76 provided in the transition part 20. From there, for example, the hydraulic line can be led further through the fork bridge 12 into a fork leg 10 and to a hydraulic brake. Then, the hydraulic line is led out and to the hydraulic brake through an opening 78 in the left fork leg 10.