DE2043912A1 - Flat-fitting, stamped brake lever for bicycle hubs and process for its manufacture - Google Patents

Description

FICHTEL & SACHS AG., Schweinfurt Patent and utility model auxiliary application

-Flat-fit stamped brake lever for bicycle hubs and process for its manufacture

The invention relates to a brake lever for bicycle hubs for support the braking torque of the lever cone of the bicycle hub on the bicycle frame, which has a hole at one end for pushing through the Has hub axle and at the other end an opening for receiving the drum screw, the hub axle end of the brake lever being intended to engage the lever cone.

The well-known shape of the brake lever is for the production in the areal fit Not suitable for punching. The manufacture of the brake lever takes place by punching out of strip material, the levers being punched out of the strip at right angles and transversely are arranged centrally symmetrically in pairs. With every punching stroke four brake levers are punched at the same time.

The invention is based on the object of a surface fit To find punching suitable brake lever with regard to its contour design, with the greatest possible material savings taking into account the given circumstances, such as bicycle frame design, material strength and processing options, the same or even higher strength Has.

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According to the invention, this object is achieved in that the lever contour on the upper edge corresponds at least over a large part of its length to the contour on the lower edge in the same direction, but offset in the longitudinal direction. This creates a brake lever shape which, on the one hand, allows the production of the brake lever in surface-locking punching with extremely little material use and, on the other hand, creates the possibility of achieving a lever contour that is very favorable in terms of strength, so that favorable stability conditions can be achieved with a very small material cross-section.

A further feature of the invention is that the horizontal line extending from the center of the opening of the lever at the end of the bandage relative to the center of the hole on the hub axis is the minimum distance between the center of the opening at the bandage side and the lower edge of the lever and twice the minimum distance from the upper edge of the lever is offset downwards.

According to the invention, it is also advantageous that when designing the brake lever above the imaginary lower edge of the lever, the lever height is plotted vertically as a function of the constant »and the upper edge of the lever is essentially approximated to this line and touched or tangent to it.

To design the lower edge of the lever, a similar procedure applied. Ee is characterized in that in the design of the brake lever under the dashed line

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* Bend # ip »unung

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direction touching tip circle, the center of which is on an in Punching direction running straight line through the center of the hub axis end hole is perpendicular to the lever height as Function of constant bending stress is applied and the lower edge of the lever to this line in the corresponding Area is approached and touches or tangents.

Another feature of the invention is that in design of the brake lever by arranging the two lines (according to claims 3 and · *), which the lever height at constant Represent the bending stress, two auxiliary lines are created, which are used to define the lever contour in this area.

According to the invention, the corresponding lines are switched in that a number of straight lines parallel to the punching direction drawn so that they intersect the two lines, starting from the center between the respective lines towards both sides half of the rod stroke is plotted and the corresponding intersection points with the straight lines result in the auxiliary lines.

According to the invention, a particularly favorable contour design results for deft brake lever in that it is formed at the end of the hub axis essentially by part of the tip circle circumference with a radius corresponding to half the punching stroke, with straight sections adjoining it tangentially, which converge to one another and to which then along the upper edge a section of a circle with the radius of the tip circle, but with a convex design, connects, while the lower section is bent ^: and calibrates, in a horizontal section towards the end of the bandage, the upper edge approximating to the previous arc.

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connected tangentially and running in the direction of the drum end at an acute angle to the horizontal on a horizontal Section adjoins, furthermore the bandage end termination consists of an essentially vertical and an upwardly directed one that runs at an acute angle to the horizontal End edge composed.

A particularly small bandwidth with little use of material with constant leverage, it can be designed accordingly the opening at the end of the drum on the brake lever. According to the invention, the arrangement is such that the opening at the end of the bandage as from the acute angle to the horizontal lying end edge of outgoing slot is designed with a preferably semicircular slot base.

In a further embodiment of the invention, the contour of the brake lever be designed so that adjacent to the acute-angled to the horizontal sections at the lower edge and upper edge flatter, also acute-angled to the horizontal sections are provided, which towards the end of the bandage in the horizontal, pass over.

The invention relates not only to the brake lever itself, but also to a method for manufacturing one Brake lever according to one of the preceding claims, by means of a surface fit Punching.

The invention consists in that the optimal bandwidth B according to the formula

B β β + R '. sin (W + ß) + c · cos Ql is determined, where in this formula s = punching stroke;

f = minimum distance from the center of the drum side iron opening

2098Π / 02Α1

opening from the top of the lever;

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C = minimum distance from the center of the drum side Opening from the lower edge of the lever j

R ^r = distance between the centers of the opening at the end of the drum and

hub axle end bore;
= c + f

is. When determining the bandwidth, the sizes s, f, c and R ^{1 are given} by the structural conditions. With knowledge of these variables from the respective structural conditions, the optimum bandwidth for punching can then easily be calculated using the above formula.

The invention will now be based on the prior art and a Series of exemplary embodiments in the description below explained in more detail with reference to the drawings.

The figures show in detail:

1 shows a brake lever according to the prior art in the assembled state with a bicycle hub and a partial side view of the bicycle frame; _;

2 shows a view of a brake lever according to the prior art;

Fig. 3 is a view of an embodiment of the invention Brake lever j

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Fig. 4- is a schematic representation of the brake lever design most important influencing factors;

Fig. 5 shows the representation of a brake lever according to the invention the strip material provided for punching the lever with an explanation of the material used to determine the optimal one Width of the band essential influencing factors;

6 shows a further embodiment of the brake lever according to the invention with modified contour design;

Fig. 7 the determination of two further brake lever contours according to the invention with related schematic representation " development of the effective material stresses for the various lever forms;

8 shows the example of the construction of a further brake lever contour according to the invention;

FIG. 9 shows a further exemplary embodiment for the construction of the brake lever contour corresponding to FIG. 8, but with a smaller one Material thickness;

Fig.10 shows the execution of a brake lever according to the invention, at

the opening on the drum side through an oblique to the end fc open slot is formed;

11 shows an embodiment variant of the brake lever of FIG. 10, however with less material thickness;

13 shows a further embodiment of the brake lever according to the invention with a reduced punching stroke compared to the aforementioned versions;

Fig.m shows a brake lever design corresponding to Fig. 13, however with less leverage;

Fig. 15 the schematic representation of the length of the brake lever occurring according to Figures 1 and 2 as well as 13 and IU

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Material stresses; V

16 shows the embodiment of the brake lever according to the invention with a small Punching stroke and formation of the opening on the drum side as a slot open to the end;

17 shows an embodiment variant according to FIG. 16, but with an opposite this lower material thickness;

Fig. 18 is a schematic representation of the material stresses of the Brake lever according to Figures 1, 16 and 17.

In Fig. 1, a brake lever 1 is shown according to the prior art. The braking force of the hub 6 should be via the brake lever 1 be transferred to the frame -4. For this purpose, the brake lever has a bore at the hub end for placing the brake lever on axis 2. The transfer of the braking force from the lever cone 5 on the brake lever 1 takes place through a non-rotatable connection between these two parts. With the frame 4 is the Brake lever 1 connected via the bandage 3, on which a screw for fixing the brake lever 1 is provided.

In FIG. 2, the brake lever according to the prior art, as it appears for example in FIG. 1, is shown again separately. The opening 7 on the drum side is a bore for receiving a screw formed. The hole at the end of the hub axis is designed as a profile hole 8 for non-rotatable attachment to a corresponding one Approach of the lever cone (5 in Fig. 1) in order to transfer the braking forces from the lever cone to the brake lever. That Profile hole 8 is attached so that its center point with the Center of the hub axis coincides. But it can also

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Other types of connection between the brake lever and the lever cone are used , for example, the profile hole can be designed with a knurling lying on a circular circumference or, a special design of the outer contour of the brake lever at the end of the hub axle can be used to fix the brake lever in the lever cone to be used.

From Fig. 2 it can be seen that a brake lever with such an outer contour cannot be produced by flat-fitting punching. Rather, the punching operation of this brake lever has been made so that the lever pairs symmetrically to one Point of symmetry are punched out of the strip of material, wherein preferably the respective tool was designed for punching out four levers during a punching stroke. The levers are there each other so that the hub axle-side end with the profile hole alternately on the right and left edge of the Material tape comes to rest, wherein the two longitudinally extending parts of the brake lever are arranged approximately parallel to each other are. This design and manufacture of the brake levers resulted in a very good material utilization according to the conventional view and efficient production, but can, as shown below in connection with exemplary embodiments of the invention will be improved significantly.

In Fig. 3 is an embodiment of the subject of the invention shown. Because the transfer of the braking force from the lever cone to the brake lever in different ways and not only can be done through a profile hole, these possibilities in Fig. 3 and in the following explanations on design

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exemplary embodiments of the invention are not discussed further. It however, it should be pointed out that in a transition from the profile hole according to FIG. 2 to a bore with an internal knurl the part of the lever at the end of the hub axis can be kept very small (diameter of the so-called tip circle), which is about a small punching stroke (tip diameter = punching stroke) can lead to further material savings Then consider saving material and durability or manufacturing costs for the knurling against each other.

The brake lever according to FIG. 3 can be produced by flat-surface punching. The lever contour on the upper edge 9 is repeated, however, offset in the longitudinal direction, at the lower edge 10. The contour runs out towards the end of the drum in a horizontal straight line. This lever can be on a strip of material, its lateral limits parallel to the punching direction SR shown in FIG. 3 run, be arranged accordingly. The bandage side The end edge of the brake lever consists of an essentially vertical section 11 and an acute angle to the horizontal, upward section 12 together. The corresponding Arrangement of the section 12 parallel to the punching direction is essential, since in this way that of the cut corner corresponding bandwidth and thus the corresponding material is saved. The contour of the lever according to FIG. 3 continues in individual together from a peripheral part of the tip circle 13, whereupon a substantially horizontal one tangentially at the upper edge Section 14 follows. At the lower edge sits down the tip circle continues in an arc 15, which merges into a horizontal section 16 up to the lever end (bandage side). At the

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Upper edge 9 goes into the horizontal section 14 with a kink an arch 17 which corresponds approximately to the arch 15. This is followed by a horizontal section 18 at the upper edge, the extends to the lever end on the drum side. This brake lever shape gives a compared to the brake lever shape according to FIG Material savings of 28.6%. There are those shown in the figures Lever shown to scale and on a 1: 1 scale.

In the Fig. «♦ certain shape conditions and influencing variables for the brake lever design are compiled with regard to their geometric relationships and will now be explained below. The distance between the center MA of the hub axle and the center MB of the drum screw is fixed by the structural dimensions of the frame and the size of the braking forces to be transmitted. This distance is denoted ^{by R 1.} As a result of the frame design, both center points cannot lie on a horizontal plane, but the center point MB must expediently be arranged below the center point MA. For the horizontal bandage-end lever part, two influencing variables are decisive for the lever design, namely f as the minimum distance between the center of the drum-side opening and the upper edge of the lever and c as the minimum distance between the center of the drum-side opening and the lower edge of the lever. These distances are fixed by means of stamping and strength considerations and cannot fall below a certain size. The diameter s of the tip circle (center point MA) corresponds to the punching stroke and is determined by which transmission means are selected for the braking torque from the lever cone to the brake lever. With R the distance between the horizontal

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- ii -

tenlunteren lever edge KU from the center point MA and with © denotes the distance of the imaginary upper lever edge, which only coincides with the actual edge above the opening 7 on the drum side, from the center point MA. This imaginary edge is called M-KO in FIG. By defining the sizes s, R ¹ , f, c, R and φ, the shape of the brake lever is essentially determined. The invention now shows possibilities to optimally design material consumption and strength ratios. ^;

In the? 5 shows the considerations that lead to the determination of the optimal bandwidth. In this figure, a brake lever according to the invention is shown in its position on the strip material used for production. This clearly shows the importance of the punching stroke s for material consumption and dimensioning, which in turn depends on the type of connection between the lever cone and the brake lever. The bandwidth is now set. f of the distance along the upper part., and in the lower part Following from the considerations in FIG. t from the distance c._ · cos (λ. (Λ is the inclination of the horizontal lever part (upper edge K ₀ or bottom _u K> The angle ι ο denotes the inclination of the connecting line between the center point M _{ß of} the opening on the drum side and the center point M ^ of the tip circle or the hole at the hub axis with respect to the imaginary horizontal lever part (K ₀ or K _u ). The mean length of the strip is thus obtained from the relationship R ^1. · sin (DC + / 3). In order to limit the number of influencing variables, Q was also expressed as a function of the influencing variables c and f

_ ₁₂ _ 209811/0241

then

sin (Y = f + c

sin

_R t

f \ itself was thus defined as f + c. After the determinants in the equation for the bandwidth, which result from the above considerations as

B = S. + RV * sin (0 (+ / 3) + c. * CosCt 2. '

results, can be determined constructively, the optimal range for the manufacture of the lever in the surface-locking punching can be determined.

In addition to these determinants for the lever contour, the Consideration with regard to minimal material consumption to take into account the lever strength, which was designated with b. at When considering the choice of the influencing variables R ', c, f, s and b, the following basic ideas must be taken into account draw:

Reducing the ^{size of R f} , which would result in a smaller bandwidth and savings in material, is to be rejected because the forces on the bicycle frame become greater.

It would be possible to reduce c and f, but this is limited in terms of the required residual wall thickness in terms of punching technology. According to the invention Somewhat more favorable conditions can be created here if instead of the hole 7 on the drum side at this point

~ ¹³ ~ 209811/0 2 41

a slot is provided. Embodiments of the invention Brake levers with a slot are explained below with reference to FIGS. 10 and 11 as well as 16 and 17.

The reduction in s is limited by the choice of more suitable Connection means between lever cone and brake lever for transmission the braking torque.

The lower limit of the dimensioning of the material thickness b results from the necessary flexural, buckling and shear strength in the Torque transfer from the lever cone to the frame.

In FIG. 7, a possibility is now explained of finding the most favorable lever shape in surface-locking punching with regard to the lever contour by considering the bending stress that occurs. Starting from the vertical straight line through the center point Mg of the drilled hole 7 on the drum side, the necessary lever height with constant bending stress is plotted along _{the horizontal straight line K u over it.} This curve is denoted by 20. According to the selected conditions, the center M _A and thus the tip circle 13 are also defined for the center Mg. The tip circle adjacent in the punching direction is denoted by 13 *. If one now assumes to design a brake lever suitable for surface-locking punching, then curve 20 can be used to determine the upper edge of the brake lever, from which the brake lever shape D then results. In the lower part

7 the bending stresses occurring U * % of the maximum value are now plotted. From this it can be seen that the lever type A used for comparison (construction according to the state of

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2) Art Fig. unfavorable stress distribution, but that also the shape of D, shows this unfavorable stress distribution only at a different point. It is now possible to find a further brake lever shape by plotting the bending stress values resulting from the curve, starting from the tip circle 13 'vertically downwards. In this way one can arrive at the brake lever shape according to E. However, this brake lever shape is also not an optimum, as can be seen from the corresponding stress distribution. Here there is a stress peak in the vicinity of the stress peak of the lever in FIG. 2.

In FIG. 8, a possibility is now explained of finding a lever shape that is much more favorable with regard to the stress distribution by mediating between the curves 20 and 21. The mediation takes place in such a way that, starting from the curve 20 and 21, parallels to the punching direction S _{R are} drawn (parallel serade 22) which intersect the curve 21 at points 23 and curve 20 at points 2 * i . If the distance between the points 23 and 24 on the respective straight line 22 is now halved and the distance L is plotted from the midpoints 25 to both sides, the mediated curves 21 'and 20 * are created 7, the result is a very favorable stress distribution, the maximum values of which are only at Bh % of the levers according to forms A, D and E. At the same time, the material saving is 34.85 % compared to type A, much cheaper than the material savings

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209811/0241

the lever shape B shown in Fig. 3, which, as already explained, is only 28.6%.

As can be seen from Fig. 7, the bending stress of the lever form F according to Fig. 8 is only about 64% of the maximum bending stress the lever type A according to the prior art (Figures 1 and 2). There but the lever shape A is not overloaded with regard to the bending stresses is, a brake lever.form can be searched for which is at further material savings roughly the same bending stresses as Has lever shape A. The same considerations as were made in FIG. 7 can now be applied to the material strength better to use, be carried out with a brake lever whose material thickness b only 3 mm instead of ^ mm as in the figures 7 and 8 is. This then leads via the appropriate steps to a lever according to FIG of curves 20 and 21 arises. By comparing it with the Fig. 8 shows that this lever is in the area of the largest Bending stress has a greater height. The maximum bending stress is based on lever type A (state of the art) and denoted by 100%, results in comparison therewith for those in FIG. 9 Lever shape J shown has a max, bending stress of about 85% and a material saving of 51.11% compared to the cost of materials according to the state of the art. The bending load is still there of the lever is still 15% lower than that of the lever-r form A.

In Fig. 10 (lever shape K), a lever was designed in which the lever end heights f and c (minimum distances between the upper edge 9 and

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Lower edge 10 from the center point M _{ß of} the opening on the drum side) were reduced so that the greatest possible material savings are achieved with approximately the same bending load as with the lever in Fig. 9 (max. Bending stress i.e. about 85% of the bending stress in lever type A). In this exemplary embodiment, the band width B is 65 mm, the punching stroke 33 and the lever end height (f + c) 11.5 mm. With the selected lever strength of b = 4 mm, there is a material saving of kl %.

In Fig. 11, a lever shape is shown in which of a Leverage strength b = 3 mm is assumed. It must then, even if Bending stresses up to the same size as with lever type A are permitted the lever end height will be increased slightly due to the lower material thickness, so that for f + c here 12.75 mm. As a result of the angles ^ and ρ, which change with the size of f + c, the result is a bandwidth of 67.5 mm in this case. Nevertheless, by reducing the material thickness and better utilization with regard to the bending load, a maximum material saving of 54.8% compared to lever type A is achieved are with the same maximum bending load.

In both cases of the lever shapes according to FIGS. 10 and 11, the opening on the bandage side is no longer designed as a bore 7, but as a slot 7 ¹ . This is the prerequisite for reducing the lever end height in order not to obtain wall thicknesses that can no longer be produced in the punching process.

In FIG. 12, the stress distribution of the lever shapes is shown in accordance with

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FIGS. 10 and 11 are shown in comparison with the prior art. From this stress distribution it can be seen that there is a relatively good utilization of material.

In Figures 13-15 are lever shapes and stress distribution shown in brake levers according to the invention, assuming a smaller tip circle 13 with only 29 mm. With these However, unlike in FIGS. 10 and 11, a hole 7 is again provided as an opening on the bandage side. Through this cannot set a certain minimum for the lever end height f + c are undercut. The size f + c was assumed here to be 13.5 mm. This then results from the design equation for the bandwidth a bandwidth of B = 74 μ and for the in 13 used a material thickness of b = 4 * mm, a material saving from Ul, 8%.

With otherwise the same sizes, only with the lower material thickness of b s -3 mm, the consideration was made for the brake lever according to FIG. This results in a somewhat modified brake lever shape compared to FIG. 13 (brake lever shape M) _9, which results in better utilization in terms of tension (can be seen from FIG. 15) and greater material savings, namely 56.5%. The brake lever shape according to FIG. IU is designated with shape N. / FIGS. 16-18 also show brake lever shapes and the associated stress distributions, with attempts being made, as in FIGS. 10 and 11, to reduce the lever end height.

16 results for a lever end height f + c of 11.5 mm

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an optimal bandwidth B of 66.5 mm, the tip diameter being and thus the punching stroke s should be 29 mm as in the previous FIGS. 13 and 14. The lever shape 0 in Fig. 16 with the material thickness b = 4 mm results in a material saving of 47.85%, whereby, as can be seen from FIG. 18, the maximum bending stress 94.5% of lever type A.

In the lever shown in Fig. 17, a lever end height f + c assumed 13 mm. This increase results from reducing the material thickness b to 3 mm because of the condition that the maximum bending stresses occurring in the current lever type A (state of the art) should not be exceeded. This results in an optimal bandwidth of W = 70 mm and a material saving of 58.8%. From Fig. 18 it can be seen that that with this lever shape P a good stress distribution is achieved with maximum material utilization. The maximum stresses that occur in lever form A are not exceeded.

Those shown in FIGS. 10 and 11, 13 and 14, and 16 and 17 Brake lever shapes are, as far as the curves shown 20 and 21 are tangent to the upper edge 9 and the lower edge 10, respectively, constructed according to the method which was explained in FIG. 7. Provided If these curves are further away from the upper or lower edge, the edges are mediated, as explained in FIGS. 8 and 9, set.

The lever shape C according to FIG. 6, F according to FIG. 8, J according to FIG. 9, K according to FIG. 10, L according to FIG. 11, M according to FIG. 13, N according to FIG. 14 and 0 16 according to FIG. 16 are essentially all similar and designed in accordance with claim 7. The contour of this Bremshebei lsi al

so on

η / t η rt 4 <t # r »» ϊ # ί

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Hub axle end essentially from the part of the tip circle circumference formed with a radius corresponding to half the punching stroke « Tangentially adjoining this are straight sections 26 on the upper edge 9 and on the lower edge 10 (on the lower edge 10) and IU (at the upper edge 9), which diverge from one another. Along the upper edge 9 then closes with a kink of the part of a segment of a circle 17 on which the same radius, namely * as the tip circle 13 has. The lower edge 10 then sits down to section 26 with a kink in a horizontal one Section 16 continues towards the end of the bandage. At the upper edge 9, the circular arc 17 connects approximately tangentially and running at an acute angle to the horizontal a section 27, which then with a kink in the horizontal to to the lever end extending section 18 connects. The bandage side The end of the lever has an essentially vertical section 11 and one that extends at an acute angle to the horizontal Section 12, each to reduce bandwidth is provided. Upper edge 9 and lower edge 10 are congruent in a certain section, but in the longitudinal direction of the lever formed offset from one another. Thus, the section 16 at the upper edge corresponds to the section 16 at the lower edge, with only because of the offset in the longitudinal direction of the section 16 more troublesome than section 18 is. It also corresponds to the section 27 on the upper edge of the section 26 on the lower edge, here the Angle relative to the horizontal, but also the length are the same. Furthermore, the 'circular arc 17 corresponds to the tip circular arc 13 at the bottom. This enables these levers to be manufactured using the surface-locking stamping process.

With the lever type P, in the interest of an extremely favorable

" ²⁰ Λ 209811/0241

Design with regard to material savings following the section 27 of the upper edge and the section 26 of the lower edge (see FIG. 17), a section 28 is provided at the top and a section 29 is provided at the bottom, which forms a smaller angle with the horizontal than the sections 26 and 27 and with another bend then merges into the horizontal 18 or 16. Because of the requirement that the lever can be manufactured using the surface-locking stamping process, the sections 28 and 29 are parallel to one another and of equal length. Their start and end points, like the start and end points of the other equally long sections (26 and 27), lie on straight lines parallel _{to the punching direction S R.} Otherwise, the section is also arranged _{parallel to the punching direction S R.}

A comparison of the various lever forms discussed can also be found in the following table:

lever Darge volume material 100 Lever- Lever end chlitz shape represents
in Fig. (cm ³ ) savings
(relative to A) 86.2 strength
(mm) Lo et A. 1 and 2 14.79 - 85.5 4th χ B. 3 10.56 28.6 64 4th X C. 6th 9,636 34.85 85 4th X F. 8th 9,636 34.85 85 4th X J 9 7.227 51.14 100 3 X χ K. 10 8.58 41 77 4th X L. 11 6.68 54.8 100 3 M. 13th 8.60 41.8 94.5 4th X N 14th 6.43 56.5 100
20th 3 X X Q 16 7.70 47.8 4th X P.
31.7 17th
.70 6.09 58.8 3
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Claims (1)

Claims . Flat-fitting, stamped brake lever for bicycle hubs and its method of manufacture 1.) Brake lever for bicycle hubs to support the braking torque of the lever cone of the bicycle hub on the bicycle frame, the one end has a hole for inserting the hub axle has and at the other end an opening for receiving the Drum screw, with the hub axle end of the brake lever is intended to attack the lever cone, characterized in that the brake lever contour on the upper edge (9) at least over a large part of its length to the contour corresponds to the lower edge (10) in the same direction, but offset in the longitudinal direction. 2, brake lever according to claim 1, characterized in that the horizontal line extending from the center point CMg) of the opening (7) of the lever Cl) on the side of the band is opposite to the ^ Center (Μ _Δ ) of the bore on the hub axle by the minimum distance Cc) of the center (Mg) of the drum-side opening C7) from the lower edge ClO) of the lever (1) and twice the minimum distance Cf) from the upper edge (9) of the lever is offset downwards. 3. Brake lever according to claims 1 and 2, characterized in that in its design over the imaginary lower edge CK _U ) of the lever (1) perpendicularly the lever height (h) as a function (curve 20) of the constant bending stress 209811/0241 ) is applied and the upper edge (9) of the lever (1) is essentially approximated to this line (20) and touches or affects them. j ». Brake lever according to Claims 1 and 2, characterized in that, in its design, under the tip circle (13 ') touching the lever (1) in the punching direction, its center point on a _{straight line running in the punching direction (S R} ) through the center point (M ^) the hub axis end hole, the lever height (h) is plotted as a function (curve 20) of the constant bending stress (ög) and the lower edge (10) of the lever (1) is approximated to this line (21) in the corresponding area and they touches or affects. 5. Brake lever according to claims 1 to H, characterized in that that in his design by mediating the two lines (20 and 21) (according to claim 3 and Ό, the represent the lever height (h) with constant bending stress, two auxiliary lines (20 'and 21 ·) are created which lead to the Determination of the lever contour in this area are used. 6. Brake lever according to claim 5, characterized in that the mediation of the corresponding lines (20 and 21) takes place in that a number of straight lines (22) parallel to the punching direction (S _R ) is drawn so that they the two lines (20 and 21), whereby half the punching stroke (f.) Is plotted from the middle (25) between the respective lines to both sides and the resulting speaking points of intersection with the straight line (22) the auxiliary " ³ " 209811/0241 lines (20V and 21 '). 7. Brake lever according to claims 1 to 6, characterized in that that its contour at the end of the hub axis essentially from part of the tip circumference (13) with a Radius is formed according to half the punching stroke (^), with straight sections adjoining it tangentially (W, 26), which diverge from one another, to the then along the upper edge (9) a circular segment (17) with the radius of the tip circle (13), but with a convex design, adjoins, while the lower edge (10) is bent and continues in a horizontal section (16) towards the end of the bandage, the upper edge (9) having one to the previous circular arc (17) approximately tangentially adjoining section (27) and in the direction of the bandage end below running at an acute angle to the horizontal adjoins a horizontal section (18), furthermore the bandage-end closure consists essentially of one . vertical (11) and one at an acute angle to the horizontal extending upward end edge (12) composed. 8. Brake lever according to claim 7, characterized in that the opening at the end of the bandage is designed as a slot (7 ^f ) extending from the end edge (12) at an acute angle to the horizontal with a preferably semicircular slot base. - If - 209811/0241 9. Brake lever according to claim 7, characterized in that adjoining the sections (26 and 27) at an acute angle to the horizontal at the lower edge (10) and upper edge (9) flatter sections (28 and 29) which also run at an acute angle to the horizontal are provided go to the horizontal (18 and 16) towards the end of the bandage, 10. A method for producing a brake lever according to one of the preceding claims by flächenschlüssxges Punching, characterized in that the optimal bandwidth B according to the formula = f. + R ¹ . Sin <PC ⁺ / 2>) + c. · CosCC is determined, where in this formula s = the punching stroke j f = the minimum distance from the center of the drum side opening from the upper edge of the lever} c = the minimum distance from the center of the bandages- |> side opening from the lower edge of the lever; sin sxn = the distance between the center points and the opening at the end of the drum and hub axle endxger bore; is. July 31, 70 EP Pa / Bb- 209811 / 02-41 Empty first page