Bicycle rim with improved rim profile

Abstract

Bicycle rim with a rim profile (1) consisting of a rim base (2) forming a hollow profile, on the outer sides of which opposite, profiled rim flanges (7, 27) are formed, wherein the rim flange (27) is wider in the foot area than in the tip area, characterized in that the profile of the rim flange (27) is conical, wherein the tangent (11) to the inner contour (14) of the rim flange with respect to the vertical (9) forms a first partial angle (28), while the tangent (10) to the outer contour (15) forms a second partial angle (29), and the sum of both partial angles (28, 29) gives the cone angle (26) of the rim flange (27).

Description

[0001] The invention relates to a bicycle rim with an improved rim profile according to the preamble of claim 1. A highly stable lightweight bicycle rim is known, for example, from DE 20 2015 102 380 U1.

[0002] A problem with bicycle rims is that under high mechanical stress, e.g., when riding over stones or other solid objects, the rim deforms, particularly in the area of ​​the two rim flanges. It is known from DE 20 2015 102 380 U1 or DE 20 2015 101 035 U1 that the rim flange is parallel to, or at least slightly wider at the bottom than at the top, both on the inner and outer sides of the rim profile. The rim flange is then either perpendicular with its longitudinal center axis (DE 20 2015 101 035 U1 or DE 20 2015 102 380 U1 or DE 20 2012 104 719 U1) or slightly inclined inwards or outwards.

[0003] When optimizing the rim profile, especially when optimizing the type and design of the rim flange, it has proven particularly advantageous to angle the rim flange slightly outwards, so that its longitudinal center axis is directed obliquely outwards, in order to ensure that impacts on the rim flange are introduced directly onto the longitudinal axis of the rim flange and therefore do not lead to premature deformation of the rim flange.

[0004] Although arrangements of rim flanges are known in the prior art (DE 20 2015 101 035 U1 or DE 20 2015 102 380 U1 or DE 20 2012 104 719 U1) which provide for a parallel alignment of the longitudinal axis to the vertical, in such designs it was disadvantageous that in the event of impacts and shocks directed obliquely from the outside to the inside on the rim flange, an immediate buckling or bulging of the rim flange occurred.

[0005] The aforementioned printed materials each show an inward-facing hook molded into the tip of the rim flange, but its shape does not contribute to the rim flange's stability. Therefore, the hook's shape and its placement at the tip of the rim flange will be disregarded in the following explanations, as such hooks can also be omitted.

[0006] The aforementioned improvements, according to the state of the art, each with a rim flange angled outwards, had led to better impact resistance of such a rim profile.

[0007] Bicycle rims with the features of the preamble of claim 1 are known from DE 10 2018 108 402 A1, US 2018 / 0 361 785 A1, EP 3 774 382 B1, US 2016 / 0 159 141 A1, and DE 10 2016 005 990 A1. US 2019 / 0 337 331 A1 discloses a bicycle rim with rim flanges.

[0008] Tests conducted by the applicant have shown that further improvement is possible by optimizing the stability of the rim flange and the transmission of impacts to the rim flange and the rim base, regardless of the presence of hooks molded onto the tip side.

[0009] The invention is therefore based on the objective of providing an optimized rim profile for a bicycle rim in which impacts coming obliquely from the outside onto the rim flange do not lead to premature deformation of the rim base or the rim profile as a whole.

[0010] The overall aim is to improve the stability of the rim profile, especially in the area of ​​the rim flange, in order to achieve the further advantage, while simultaneously improving the stability of such a rim profile, that the required wall thicknesses can be minimized in order to provide a lighter bicycle rim.

[0011] To solve the problem posed, the invention is characterized by the technical teaching of claim 1.

[0012] According to the invention, the tangent to the inner contour of the rim flange with respect to the vertical forms a first partial angle, while the tangent to the outer contour forms a second partial angle, and the sum of both partial angles yields the cone angle of the rim flange.

[0013] The rim flange is significantly wider at the base than at the tip, meaning that the two areas at the base of the rim flange located to the left and right of the longitudinal axis are positioned further from the vertical than the two upper areas. This differs from the prior art, as such a rim flange can absorb the forces much better and is considerably less prone to dents under sudden impacts.

[0014] Extensive tests were conducted with rim profiles using 3D aluminum printing to provide an optimized rim profile, and it was found that such an optimized rim flange, which basically has a conical shape that tapers radially outwards, offers significantly better stability.

[0015] The invention will now be explained in more detail with reference to a drawing that illustrates only one embodiment.

[0016] They show: Fig. 1 (State of the art): Cross-section through a bicycle rim according to the state of the art. Fig. 2: Cross-section through a bicycle rim according to the invention. Fig. 3: An enlarged representation of the rim flange according to the invention in the novel shape according to Fig. 2. Fig. 4: The same representation as Fig. 3 with a description of further preferred features. Fig. 5: The same representation as Fig. 4 with an additional illustration of another variant. Fig. 6: The same representation as the Fig. 3 and Fig. 4 showing further details.

[0017] The Fig. Figure 1 shows a section through a rim profile 1 according to the prior art, where a rim base 2 is present in a manner known per se, which forms an inner base profile 3, opposite an outer base profile 4.

[0018] In the inner floor profile 3, a hump 6 is incorporated in a manner known per se, which is intended to prevent the tire from slipping towards the inside, with the tire being received in a tire seat 5.

[0019] The rim profile 1 according to the prior art and according to the invention is bounded externally by two mutually antiparallel or parallel rim flanges 7, 27. The following description focuses solely on the shaping of a single rim flange 7, 27, as the opposite rim flange 7, 27 is identical. The rim profile 1 according to the prior art and the invention is preferably symmetrical about the longitudinal center axis 32. However, this is not a requirement of the invention. The rim profile can therefore also be asymmetrical, in which case the rim flanges remain symmetrical to each other.

[0020] It is also known to arrange an inwardly directed hook 8 on the inside of each rim flange 7, 27, which prevents the tire, seated in the tire seat 5, from being lifted outwards out of the rim flange 7, 27 by the resulting internal pressure of the tire. However, such a hook 8 can also be omitted and is not necessary for the solution.

[0021] The Fig. According to the state of the art, 1 points the vertical 9 to the rim flange 8 and it is from the left side of the Fig. 1. It is evident that the tangent 10 to the outer surface of the rim flange 7 is directed obliquely outwards, and that the tangent 11 to the inner surface of the rim flange 7 is also directed obliquely outwards, with the two tangents 10, 11 being parallel to each other according to the prior art. A conical shape of the rim flange 7, in which the two tangents 10, 11 intersect at a point 25 (see Fig. 6) cutting above the rim flange 7, is therefore not apparent from the prior art.

[0022] The rim flange 7 (the area between the two lateral lines 31 and the area above it) is generally parallel or slightly wider at the bottom than at the top. According to the state of the art, the two lateral lines 31 are parallel to each other. The wall thickness 12 is therefore constant along the length of the rim flange 7. The longitudinal center line 13 through the rim flange 7 is either perpendicular (parallel to the vertical 9) or inclined slightly inwards or outwards (towards the vertical 9). The arrow directions 30 indicate approximately the directions of external forces that lead to deformation and dent formation on rims.

[0023] The Fig. Figure 1 also shows that outwardly directed rim horns 7, whose longitudinal center line 13 runs parallel to the tangents 10, 11, enable better absorption of force shocks or force impulses acting on the tip of the respective rim horn 7 in the directions of the arrows 30.

[0024] The foregoing description concerning the position, location and dimensioning of a rim flange 7 and all other parts of the rim profile 1 according to the prior art also applies, with the foregoing reference numerals and their description, to the novel rim flange 27 described below, unless different reference numerals have been used for the same parts.

[0025] The shaping of the rim flange 7, according to the state of the art, is in need of improvement, as can be seen from the Fig. 2 is described. There, a rim flange 27 according to the invention is shown, wherein the two rim flanges 27 arranged symmetrically to the longitudinal center axis 32 are profiled identically and designed in the same way, so that the description of a single rim flange 27 is sufficient.

[0026] On the new rim, the rim flange 27 is much wider in the lower area (foot area) than in the upper area (toe area). The wall thickness 22 therefore decreases uniformly (linearly) from the foot area to the toe area.

[0027] Furthermore, both lower areas of the rim flange 27 (see lines 31) move further away from the vertical 9 than the two upper areas, so that the lines 31 running from the toe area to the toe area form a cone together. This is shown by the Fig. 6 explained in more detail.

[0028] This is what sets the new rim apart from all others on the market. The rim flange 27 can absorb the forces much better and is significantly less prone to dents.

[0029] With respect to vertical 9, it is from Fig. 2. It can be seen that the wall thickness 22 at the bottom in the foot area at the rim flange 27 is greater than the wall thickness 23 at the top (see Fig. 3) and that, due to the conical design of the rim flanges 27 according to the invention, better load absorption of force shocks or impulses in the directions of arrow 30 is ensured.

[0030] While the state of the art according to Fig. 1. Since the wall thickness 12 of the respective rim flange 7 was the same over its entire longitudinal extent, according to the invention the wall thickness 22 of the rim flange 27 in the foot area is greater than the wall thickness in the tip area of ​​the respective rim flange 27.

[0031] The Fig. Figure 3 also shows that in certain versions, hook 8 can be omitted.

[0032] The Fig. Figure 3 shows a preferred embodiment where it can be seen that the respective rim flange 27 has a first, greater wall thickness 22 in the bottom or foot area than the second wall thickness 23 in the tip area. It follows that the tangent to the inner contour 14 of the rim flange 27 is oriented antiparallel to the tangent to the outer contour 15.

[0033] The Fig. Figure 4 also shows a further advantage in the improved shaping of the rim flange 27 in its conical design. This allows the wall section 17 of the outer base profile 4 to be drawn more steeply inwards onto the outer base profile 4. Starting from a convex outer arc surface 18, a concave inner arc surface 19 adjoins, which finally merges into the inwardly directed wall surface 17 of the outer base profile 4. This allows the wall section 17 to be made thinner in thickness 21, resulting in a weight saving.

[0034] Furthermore, its longitudinal center axis 33 can be drawn inwards (towards the longitudinal center axis 32) at a steeper angle 34. It is preferred that the longitudinal center axis 33 of the wall section 17 forms an angle 34 to the vertical 9 in the range of 30 to 60 degrees, preferably 45 degrees. This allows impacts acting obliquely from the outside on the rim flange 27 to be absorbed directly by the obliquely drawn wall section 17. Because of this favorable force transmission, its wall thickness can be reduced without losing stability.

[0035] The Fig. Figure 5 illustrates the advantage of the inward-facing installation of the wall section 17 using an example of a prior art embodiment. The wall section 17 according to the invention is shown internally and in solid lines, and a conventional wall section 24 is also shown. A wall section according to the invention, recessed inwards, has a smaller surface area and therefore a lower weight compared to a wall section according to the prior art.

[0036] The Fig. 5 shows - just like the Fig. 3 and Fig. 4 - that the longitudinal centerline 13 through the conical rim flange 27 forms an angle 16 to the vertical 9, that is, that the entire conical rim flange 27 is slightly turned outwards in order to - as in Fig. 2 shown - to better absorb the impulses acting from the outside in the directions of arrow 30 and to transfer them to the rim base 2. The inclination is carried out at an acute angle to the vertical 9, which is preferably in the range between 5 and 15 degrees.

[0037] However, the invention is not limited to rim flanges 27 that are angled outwards. In other embodiments, the angle 16 may be zero or even negative. In the latter case, the rim flange 27 would be inclined inwards.

[0038] Out of Fig. 6 further details of the shaping of the rim flange 27 emerge, where it is first apparent that the tangent 11 to the inner contour 14 of the rim flange in the direction of the vertical 9 forms a first partial angle 28, while the other tangent 10 to the outer contour 15 forms a further partial angle 29 and the sum of both partial angles 28, 29 gives the cone angle 26 of the novel shaping of the conically tapered rim flange 27.

[0039] It is not necessary for the two partial angles 28 and 29 to be equal. In a preferred embodiment, the partial angle 28 with respect to the vertical 9 lies in the range between 5° and 15°, preferably 12.5°, while the partial angle 29 lies in the range between 1° and 10°, preferably 5°. This results in a preferred cone angle 26 of 17.5°, preferably within a range of 10° to 25°.

[0040] This results in the two tangents 10, 11 intersecting in the region of an intersection point 25 located beyond and above the rim flange 27, which was not the case in the prior art. The intersection point 25 is preferably located at a distance above the conical tip of the rim flange 27 that corresponds to approximately 50% to 100% of the length of the rim flange 27.

[0041] In the prior art, there were only mutually parallel tangents 10, 11, as described in Fig. 1 is shown and the now superior conical profile shape of the rim flange 27 leads to improved absorption of impacts on the rim base 2 and optimized profiling with lower wall thicknesses, resulting overall in a lighter rim profile, the likes of which were previously unknown in the state of the art.

[0042] Furthermore, by reducing the wall thicknesses in the wall section 17, it has been possible to optimize the rim profile 1 and to achieve a weight saving in the connection of the rim horn 27 to the outer base profile 4.

[0043] The preferred feature of the invention provides that material is removed from the tip area of ​​the tapered rim flange 27 and transferred to the foot area of ​​the rim flange 27. This allows the foot area to be stabilized, enlarged, and stiffened, while the tip area can be narrowed. In a preferred embodiment, this results in a constant weight of the rim profile compared to the prior art, but significantly greater stability against external impacts acting on the rim flange can be achieved. Drawing legend 1 Rim profile (state of the art) 2 Rim base 3. Bottom inner profile 4 Bottom outer profile 4' 5 tire seat 6 Hump 7 rim flange 8 hooks 9 Vertical 10 Tangent (outside of 7) 11 Tangent (inside of 7) 12 Wall thickness (out of 7) 13 Longitudinal centerline 14 Inner contour (of 27) 15 Outer contour (of 27) 16 angles (between 9 and 13) 17 Wall section (4) 18 arc outer surface 19 inner surface of the arc 20 Rim profile (invention) 21 Wall thickness (out of 17) 22 Wall thickness (bottom) 23 Wall thickness (top) 24 wall section (of 4) 25 Intersection 26. Cone angle 27 rim flange 28 partial angles (inside) 29 partial angles (outside) 30 Arrow direction 31 lateral line (at 7) 32 Longitudinal center axis

Claims

[1] Bicycle rim with a rim profile (1) consisting of a rim base (2) forming a hollow profile, on the outer sides of which opposite, profiled rim flanges (7, 27) are formed, wherein the rim flange (27) is wider in the foot area than in the tip area, characterized by , that the profile of the rim flange (27) is conical, wherein the tangent (11) to the inner contour (14) of the rim flange with respect to the vertical (9) forms a first partial angle (28), while the tangent (10) to the outer contour (15) forms a second partial angle (29), and the sum of both partial angles (28, 29) gives the cone angle (26) of the rim flange (27). [2] Bicycle rim according to claim 1, characterized by , that the tangent (11) to the inner contour (14) of the rim flange (7, 27) intersects the tangent (10) to the outer contour (15) at an intersection point (25) which is above the tip of the rim flange (7, 27). [3] Bicycle rim according to claim 2, characterized by, that the distance of the intersection point (25) to the tip of the rim flange (7, 27) corresponds to approximately 50% to 100% of the length of the rim flange (7, 27). [4] Bicycle rim according to one of claims 1 to 3, characterized by , that, disregarding a hook (8) molded onto the tip of the rim (7, 27), the wall thickness (22) at the bottom in the foot area of ​​the rim (7, 27) is greater than the wall thickness (23) at the top in the tip area. [5] Bicycle rim according to one of claims 1 to 4, characterized by , that the cone angle (26) of the rim horn (7, 27) is in the range between 10 and 25 degrees, preferably 17.5 degrees. [6] Bicycle rim according to any one of claims 1 to 5, characterized by , that the wall part (17) which connects the foot side of the rim horn (7, 27) with the bottom outer profile (4) of the rim profile (1) is reduced in width. [7] Bicycle rim according to claim 6, characterized by, that starting from the foot side of the rim horn (7, 27) a convex outer arc surface (18) is followed by a concave inner arc surface (19), which runs into the obliquely inwardly directed wall surface of the wall part (17) into the bottom outer profile (4). [8] Bicycle rim according to claim 7, characterized by , that the longitudinal center axis (33) of the wall part (17) forms an angle (34) to the vertical (9) in the range between 30 and 60 degrees, preferably 45 degrees. [9] Bicycle rim according to any one of claims 1 to 8, characterized by , that the conical rim horn (27) is angled outwards and its longitudinal center line (13) forms an acute angle (16) to the vertical (9).

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