RIM FOR AN AT LEAST PARTIALLY MUSCLE-POWERED BICYCLE

Abstract

A rim, having a rim body with rim flanks, a rim well and a rim base, in which the flanks abut in the radially most inwardly point, and with opposed rim flanges, each extending from one of the flanks up to a radially most outwardly point, so that the rim flanges form opposed side walls with the flanks. The widest spot of the rim body lies beneath the rim well and above a horizontal centerline. The width in the widest spot is at least one quarter larger than a clear rim width between the rim flanges. The side walls show a defined curvature shape with an inflection point which is disposed between the radially most outwardly point and the widest spot and lies external of the rim flange. In the inflection point, a concave curvature makes a transition to a convex curvature lying between the inflection point and the widest spot.

Claims

1. A rim for an at least partially muscle-powered bicycle, comprising: a rim body with opposed rim flanks; a rim well and a rim base, in which the rim flanks abut in the radially most inwardly point, and with opposed rim flanges, each extending from one of the rim flanks up to a radially most outwardly point, so that the rim flanges together with the rim flanks form opposed side walls, which extend from the radially most inwardly point up to the radially most outwardly point; wherein the widest spot of the rim body lies beneath the rim well and above a horizontal centerline; in the widest spot, the width is at least one quarter larger than is a clear rim width between the rim flanges, and that the side walls each show a defined curvature shape with at least one inflection point, which is disposed between the radially most outwardly point and the widest spot and lies external of the rim flange; and in the inflection point, a concave curvature makes a transition to a convex curvature; and the convex curvature lies between the inflection point and the widest spot, and the concave curvature lies between the inflection point and the radially most outwardly point.

2. The rim according to claim 1, wherein the side walls each comprise a cross-sectional geometry with an S-shaped outside surface between the radially most outwardly point and the widest spot.

3. The rim according to claim 1, wherein the widest spot is closer to the rim flange than to the horizontal centerline.

4. The rim according to claim 1, wherein the maximum width is at least 1.4 times the clear rim width.

5. The rim according to claim 1, wherein the clear rim width is less than 32 mm, and wherein the maximum width is at least 8 mm larger than the clear rim width.

6. The rim according to claim 1, wherein the concave curvature runs from the inflection point continuously up to the rim flange and terminates on the rim flange at a distance from the radially most outwardly point.

7. The rim according to claim 1, wherein the width of the rim body also increases along the concave curvature.

8. The rim according to claim 1, wherein at least 70% of the width increase, which takes place along the concave curvature and the convex curvature on the whole, is achieved over maximally 25% of the height of the rim body and external of the rim flange.

9. The rim according to claim 1, wherein the convex curvature has a minimal radius, which is smaller than the minimal radius of the concave curvature, and wherein the minimal radius of the concave curvature lies on the rim flange.

10. The rim according to claim 1, wherein the concave curvature consists of a rim flange curvature section running along the rim flange, and of a rim flank curvature section running along the rim flank, and wherein the width of the rim body on the whole increases less along the rim flange curvature section than along the rim flank curvature section.

11. The rim according to claim 10, wherein the width of the rim body increases more along the rim flank curvature section at least by the factor of 1.2 than it does along the rim flange curvature section.

12. The rim according to claim 10, wherein the width of the rim body increases by a first width along the rim flank curvature section and the convex curvature, and wherein the width of the rim body increases by a second width along the rim flange curvature section, and wherein the first width increase is at least twice the second width increase.

13. The rim according to claim 1, wherein the total width increase deviates along the concave curvature by maximally 10% from the total width increase along the convex curvature.

14. The rim according to claim 1, wherein the concave curvature and the convex curvature each show a radius whose value varies over the length of the curvature shape.

15. The rim according to claim 1, wherein a further inflection point is disposed on the rim flange, and wherein the further inflection point lies between the inflection point and the radially most outwardly point, and wherein in the further inflection point, the concave curvature makes a transition to a further convex curvature which extends at least up to the radially most outwardly point.

16. The rim according to claim 15, wherein at least 70% of the width increase taking place between the further inflection point and the widest spot of the rim body on the whole, is achieved external of the rim flange, and wherein the width of the rim body decreases from the further inflection point up to the radially most outwardly point.

17. The rim according to claim 15, wherein a tangent adjacent to the further inflection point at the rim flange shows an angle of at least 82? to the horizontal centerline.

18. The rim according to claim 1, wherein an inside surface of the rim flange is inclined to the horizontal centerline at an angle of at least 85?.

19. The rim according to claim 1, wherein the rim body is free of brake flanks.

20. The rim according to claim 1, wherein the rim body is manufactured of a plastic.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The figures show in:

[0044] FIG. 1 a schematic illustration of a bicycle with rims according to the application;

[0045] FIG. 2 a schematic illustration of a rim according to the application in a perspective, cross sectional view;

[0046] FIG. 3 a schematic illustration of a rim according to the application in a cross sectional view;

[0047] FIG. 4 the rim according to FIG. 3 with a curvature ridge;

[0048] FIG. 5 a schematic detail illustration of the rim in FIG. 4; and

[0049] FIG. 6 a schematic detail illustration of a rim according to the application in a cross sectional view.

DETAILED DESCRIPTION

[0050] FIG. 1 shows an at least partially muscle-powered bicycle 100, which is presently configured as a sports bicycle for cross-country races and e.g. as a gravel bike or a cyclo-cross bicycle. The bicycle 100 has a front wheel 101 and a rear wheel 102 having one rim 1 each according to the application. The two wheels 101, 102 are provided with spokes 109 for connecting the rim 1 with the hubs 110. To this end, the rim 1 is provided e.g. with spoke holes. To allow fast and safe riding also on drystone and unpaved roads, the rims 1 are equipped with tires 114, whose width is e.g. 30 mm to 50 mm.

[0051] The bicycle 100 comprises a frame 104, a handlebar 101 with grips 114, a saddle 107, a fork or suspension fork 105. For cross-country races in particularly difficult terrain, a rear wheel damper, not shown, may be provided. A pedal crank 112 with pedals serves for driving. Optionally, the pedal crank 112 and/or the wheels 102, 103 may be provided with an electrical auxiliary drive. The hubs of the wheels 102, 103 may each be fastened to the frame 104 or the fork 105 by means of a clamping system 113 (such as a through axle or a quick release).

[0052] The rim 1 employed in the bicycle 100 will now be described with reference to the FIGS. 2 and 3. The rim 1 comprises a rim body 2, which comprises opposed rim flanks 3, a rim well 12 and a rim base 22, and opposed rim flanges 4. Supplementarily to the rim body 2, the rim 1 may comprise further components, for example sealants for the use of tubeless tires. The rim body 2 shown is equipped without any brake flanks.

[0053] The rim flanks 2 abut in a radially most inwardly point 15, extending from there to the rim flanges 4. The rim flanges 4 start from the rim flanks 3, extending up to a radially most outwardly point 5. This results in opposed side walls 20, extending from the radially most inwardly point 15 up to the radially most outwardly point 5. The rim flange 4 begins where a horizontal plane of the rim well 12 intersects the side wall 20. In the example shown, the reference numeral 12 points toward this plane. This plane also corresponds to the supporting surface of the tire and serves to determine the size of the rim 1 according to ETRTO.

[0054] The rim base 22 may show recesses where spokes 109 respectively nipples can be attached. The rim well 12 may comprise openings through which to access the spokes 109 respectively nipples for installation and servicing.

[0055] The clear rim width 14 between the rim flanges 4 shown is dimensioned such that the usual tire widths in cross-country races can be safely operated on the rim 1. Particularly preferably, for example tires between 30 mm and 40 mm can be employed. For aerodynamic optimization of the rim 1 or the combination of the rim 1 with cross-country tires, the clear rim width 14 chosen is the narrowest possible and is for example 24 mm. The clear rim width 14 is measured in the narrowest spot 24 between the rim flanges 4.

[0056] In order to offer the best possible aerodynamic properties, the widest spot 25 of the rim body 2 lies beneath the rim well 12 and above a horizontal centerline 35. It has been shown to be of particular advantage for the widest spot 25 to lie at least at 65% of the height 45 of the rim body 2. For example, the height 45 shown is 50 mm, and the widest spot 25 lies at a height 45a of 35 mm. Then the difference 45b is 15 mm. In this example, the widest spot 25 then lies at 70% of the height 45 of the rim body 2.

[0057] For the rim 1 to provide optimal aerodynamics including in combination with the appropriately wide cross-country tires, the width 250 in the widest spot 25 is at least one quarter larger than is the clear rim width 14. For example a width 250 of 36.5 mm is advantageous. This is why the maximum width 250 is 12.5 mm larger than the clear rim width 14. Thus, the rim 1 can be equipped with a wide range of cross-country tires, without risking that the widest spot 25 is too narrow compared to the tire. This ensures that even cross-country tires do not laterally protrude beyond the widest spot 25.

[0058] However, the dimensioning described above results in the problem that the difference 250b must be overcome across a very small portion of the height 45 (for example, difference 45b=15 mm). To avoid material accumulations or aerodynamic problem areas, the side walls 20 are provided with special curvature shapes 6. The curvature shape 6 of the pertaining side wall 20 has an inflection point 16 in which a concave curvature 26 makes a transition to a convex curvature 36. The curvature shapes 6 provide the side walls 20 with a cross-sectional geometry 32 having an S-shaped outside surface.

[0059] The concave curvature 26 runs from the inflection point 16 up to a further inflection point 46 on the rim flange 4. A further convex curvature 56 follows, from the further inflection point 46 in the direction to the radially most outwardly point 5. At its top end, the further convex curvature 56 makes a transition to a straight section 66, which extends up to the radially most outwardly point 5. The curvature shape 6 as well as the further convex curvature 56 are illustrated in the FIG. 3 on the left side wall 20 by an enlarged line width. The curvature shape 6 with its special cross-sectional geometry 32 extends from the further inflection point 46 downwardly to the widest spot 25.

[0060] The FIGS. 4 and 5 show an exemplary rim 1 to illustrate the curvature shape 6. To this end, a so-called curvature ridge is inserted in the FIG. 4 along the left side wall 20. The curvature ridge shows a plurality of rays which by their length represent the curvature at the starting point of the ray. The longer the rays, the larger the curvature. Since the curvature corresponds to the reciprocal value of the pertaining radius, the radius is smaller the longer the rays are. To enhance comprehensibility, FIG. 5 shows the rays of the curvature ridge proportionally shorter compared to FIG. 4.

[0061] The curvature ridge enables clear recognition of which positions are located the inflection point 16, the concave curvature 26 and the convex curvature 36, and the further inflection point 46, and the further convex curvature 56. One can also clearly see that the further convex curvature 56 shows a continuous radius. For example, the radius is 1.5 mm.

[0062] The curvatures 26, 36, however, show a variable radius. For example, the concave curvature 26 has a maximal curvature with a radius of 22 mm+/?10%. For example, the convex curvature 36 has a maximal curvature with a radius of 11 mm+/?10%. In other words, the convex curvature 36 has a minimal radius which is smaller than the minimal radius of the concave curvature 26.

[0063] Moreover, one can clearly recognize the geometric smoothness of the transition from the convex curvature 36 to the further curvature shape 60 lying beneath, of the side wall 20. The jump 60a in the curvature ridge indicates a G1 smoothness respectively a tangent smoothness. In the region of the transition to the convex curvature 36, the further curvature shape 60 has e.g. a maximal curvature with a radius of 59 mm+/?10%.

[0064] This concave curvature 26 consists of a rim flange curvature section 261 and a rim flank curvature section 262 (see FIG. 5). The rim flange curvature section 261 extends from the further inflection point 46 along the rim flange 4 up to the rim well 12 respectively its horizontal plane (shown in broken lines). This is where the rim flank curvature section 262 begins, extending up to the inflection point 16.

[0065] FIG. 5 shows broken, vertical lines, illustrating the width increase along the individual sections of the curvature shape 6. What is shown is, the increase 6a of the width along the concave curvature 26 and the convex curvature 36 (thus along the entire curvature shape 6 from the further inflection point 46 as far as the widest spot 25). Also shown are: the increase 26a in width along the concave curvature 26, the increase 36a in width along the convex curvature 36, the increase 261a in width along the rim flange curvature section 261, the increase 262a in width along the rim flank curvature section 262.

[0066] In an exemplary configuration of the rim 1 (preferably the rim 1 described above) the increase 6a is 3.055 mm. Thereof, the increase 36a is 1.353 mm, and the increase 26a is 1.702 mm. The increase 26a includes the increase 262a at 1.017 mm and the increase 261 A, as little as 0.68 mm. Thus, the width increases only very little along the rim flange curvature section 261. The width then increases very rapidly in the rim flank curvature section beneath, and along the convex curvature 36. The width increase along the rim flank curvature section 262 and the convex curvature 36 is more than three times the width increase along the rim flange curvature section 261.

[0067] Thus, more than 70% of the increase 6a of the width, on the whole taking place between the further inflection point 46 and the widest spot 25, is achieved external of the rim flange 4. The increase 6a of the width in the example shown takes place over a height difference of as little as 13.7 mm. Of this height difference, 9.5 mm lie beneath the rim well 12 and external of the rim flange 4. Given a total height 45 of the rim body 2 of 50 mm, the height difference of 9.5 mm provides a portion of 19%. Thus, more than 70% of the increase 6a in width along the concave curvature 26 and the convex curvature 36 are achieved over as little as 19% of the height 45 of the rim body 2 and at the same time external of the rim flange 4.

[0068] FIG. 6 shows an exemplary embodiment of the rim 1, where the rim flanges 4 are inclined at a defined angle. A tangent 34 adjacent to the further inflection point 46 e.g. shows an angle of 84? to the (not visible) horizontal centerline 35. Moreover, an inside surface 44 of the rim flange 4 is inclined at an angle of 87? to the horizontal centerline 35. This results in a setting angle for the rim flange 4 on its outside surface of 6? and on its inside surface 44, of 3? to the vertical axis.

[0069] These setting angles enhance the demolding process in manufacturing the rim 1, which is manufactured for example from a fibrous composite material in a suitable shaping tool. Again, the curvature shape 6 offers considerable advantages for the steep setting angle to not lead to a conflict of goals with the widest spot 25 which is to lie the closest possible to the rim flanges 4. The invention presently represented overcomes the large difference 250b over a very minor portion of the height 45, without requiring the rim flanges 4 to be configured inclined or with a large wall thickness.

[0070] While a particular embodiment of the present rim for an at least partially muscle-powered bicycle have been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.

TABLE-US-00001 List of reference numerals: 1 rim 2 rim body 3 rim flank 4 rim flange 5 most outwardly point 6 curvature shape 6a increase 12 rim well 14 rim width 15 most inwardly point 16 inflection point 20 sidewall 22 rim base 24 closest spot 25 widest spot 26 concave curvature 26a increase 32 cross-sectional geometry 34 tangent 35 centerline 36 convex curvature 36a increase 44 inside surface 45 height 45a height 45b difference 46 inflection point 56 convex curvature 60 curvature shape 60a jump 66 straight section 100 bicycle 101 handlebar, handle 102 wheel, front wheel 103 wheel, rear wheel 104 frame 105 fork, suspension fork 107 saddle 109 spoke 112 pedal crank 113 clamping system 114 tire 250 width 250b difference 261 rim flange curvature section 261a increase 262 rim flank curvature section 262a increase