Crank set with chain guard ring and fastening element

Abstract

A crank set for a two-wheeler, the crank set comprising a crank with a crank spider, a chainring and a chain guard ring, the chainring being fastened to the crank spider by fastening elements, and the fastening elements pressing the chainring and the crank spider against one another along a pressing direction. A clamped area of the chain guard ring is clamped in a clamping zone between at least one of the fasteners by which the chainring is secured to the crank spider and the crank spider or chainring and thereby secured to the crank set.

Claims

1. A crank set for a two-wheeler, the crank set comprising a crank with a crank spider, a chainring and a chain guard ring, the chainring being fastened to the crank spider by fastening elements, the fastening elements are pressing the chainring and the crank spider against each other along a pressing direction, wherein a clamped area of the chain guard ring is clamped in a ring-shaped clamping zone between at least one of the fastening elements with which the chainring is fastened to the crank spider and the crank spider or the chainring and is thereby fastened to the crank set, wherein the at least one fastening element contacts the chain guard ring in the clamping zone, wherein the clamped area is deformed by the screwing of the at least one fastening element in a direction parallel to the pressing direction, wherein the fastening element has an annular shoulder, wherein a pressing surface is provided on the annular shoulder, wherein the fastening element has a ring-shaped clamping surface pointing in a same direction as the pressing surface, wherein the ring-shaped clamping surface delimits the ring-shaped clamping zone on a side remote from the chainring and/or the crank spider, wherein the clamping surface surrounds the annular shoulder, wherein the material of the clamping zone of the chain guard ring where the at least one fastening element contacts the chain guard ring is a plastic material that is more easily deformable than a second material of the chainring and a third material of the crank spider.

2. The crank set according to claim 1, wherein the at least one fastening element has a screw-in element and a screw-on element, wherein the screw-in element and the screw-on element are screwed together for pressing the chainring onto the crank spider.

3. The crank set according to claim 2, wherein the fastening screw-in element and/or the screw-on element has the pressing surface.

4. The crank set according to claim 3, wherein the pressing surface is of ring-shaped design.

5. The crank set according to claim 3, wherein the pressing surface is arranged on an annular shoulder of the screw-in element and/or of the screw-on element.

6. The crank set according to claim 5, wherein the clamping zone surrounds the annular shoulder.

7. The crank set according to claim 2, wherein the screw-on element has an outwardly pointing circular cylindrical surface in the region of the screw connection.

8. The crank set according to claim 2, wherein the screw-in element and/or the screw-on element has the clamping surface which delimits the clamping zone on the side remote from the chainring and/or the crank spider.

9. The crank set according to claim 1, wherein the clamped-in region clamped area is deformed by the screwing of the at least one fastening element in the direction parallel to the pressing direction.

Description

(1) Further practical forms of implementation and advantages of the invention are described below in connection with the drawings. It is shown:

(2) FIG. 1 a sectional view of a part of a crank set in the area of the connection between chainring and crank spider,

(3) FIG. 2 a view of the chain guard ring of the crank set from FIG. 1,

(4) FIG. 3 a sectional view of the chain guard ring from FIG. 2 along the section line A-A,

(5) FIG. 4 an enlargement of area B in FIG. 3,

(6) FIG. 5 a view of the screw-in element from FIG. 1

(7) The crank set 10 shown as an example has a crank with a crank spider 12. A chainring 14 is attached to the crank spider 12. The chainring 14 can be fastened with a fastening element comprising a screw-in element 16 and a screw-on element 18. The screw-in element 16 and the screw-on element 18 can be screwed together as shown in the example. As shown as an example, this screw connection can generate a pressing force which presses the chainring 14 and the crank spider 12 together along the pressing direction 20.

(8) The crank set 10 shown as an example also has a chain guard ring 22. The chain guard ring 22 is also attached to the crank set 10 by the fastening element with which the chainring 14 is fastened to the crank spider 12. For this purpose, the fastening element may have a ring-shaped shoulder 24 as shown in the example. As shown in the example, a pressing surface 26 can be provided on this annular shoulder 24, whichas shown in the exampleintroduces the pressing force along the pressing direction 20 into the crank spider 12. A clamping surface 28, also ring-shaped and pointing in the same direction as the pressing surface 26, surrounds the annular shoulder 24 in the example shown.

(9) Between the clamping surface 28 and the chainring 12, a ring-shaped clamping zone also forms in the example shown, which surrounds the annular shoulder 24. Within this clamping zone, there is a clamped area 30 of the chain guard ring 22. This area 30, which is located within the clamping zone, is also ring-shaped. The area 30 is deformed, i.e. compressed along the pressing direction 20. The compression path 32 by which the area 30 is compressed along the contact pressure direction 20 is at least 0.05 mm, preferably at least 0.15 mm, and/or at most 1 mm, especially at most 0.2 mm.

(10) Correspondingly, the material thickness 34 of the area 30 before attaching the chain guard ring 22 to the crank set 10 can be at least 1 mm, preferably at least 1.15 mm, and/or at most 1.4 mm, preferably at most 1.2 mm.

(11) The extension 36 of the clamping zone along the pressing direction 20 can be at least 0.8 mm, preferably at least 1 mm, and/or at most 1.2 mm, preferably at most 1.15 mm.

(12) As can be seen in FIGS. 2 to 4, the material thickness 34 of the area 30 may be less than the material thickness of the surrounding areas of the chain guard ring 22. The difference 38 of the material thicknesses may be at least 0.05 mm, preferably at least 0.15 mm, and/or at most 1 mm, preferably at most 0.2 mm.

(13) As shown in FIG. 5, the distance between the clamping surface 28 and the pressing surface 26 may correspond to the extension 36.

(14) FIG. 5 shows an example of a screw-in element 16, but in the view shown in FIG. 5 the thread of the screw-in element 16 is not shown. The diameter 40 of the annular shoulder 24 can be at least 10.2 mm, preferably at least 11.5 mm and/or at most 15 mm, preferably at most 12.5 mm.

(15) The outer diameter 42 of the clamping surface 28 can be at least 11.7 mm, preferably at least 13 mm and/or at most 16.5 mm, preferably at most 15 mm.

(16) The features of the invention disclosed in the present description, in the drawings and in the claims may be essential both individually and in any combination for the realisation of the invention in its various forms. The invention is not limited to the described embodiments. It may be varied within the limits of the requirements and taking into account the knowledge of the competent person.

REFERENCE LIST

(17) 10 crank set 12 crank spider 14 chain ring 16 screw-in element 18 screw-on element 20 pressing direction 22 chain guard ring 24 annular shoulder 26 pressing surface 28 clamping surface 30 area 32 compression path 34 material thickness 36 extension 38 material thickness difference 40 diameter 42 diameter