DE2043912C3 - Flat-fitting, stamped brake lever for bicycle hubs with a coaster brake device - Google Patents

Description

B = γ + R '■ sin (α + ft) + c ■ cos *
is determined, being in this formula

sin «

arejS
R '

is.

the punch feed,

the minimum distance from the center point

Mb of the opening (7) on the drum side of

the upper contour (K ₀ , 9) of the lever;

the minimum distance from the center point

Mb of the opening (7) on the drum side of

the lower contour (Ku, 10) of the lever;

the distance between the centers of the opening Mb at the end of the bandage and opening Ma at the end of the hub; c + f

The invention relates to a brake lever for bicycle hubs with a coaster brake device for support the braking torque of the lever cone of the bicycle hub on the bicycle frame with a widened head part on the hub axle side with a

Breakthrough at least for inserting the hub axle and a tail part on the bandage side with an opening for the bandage screw, the center of gravity of the head part (I ⁰ S brake lever being offset from the longitudinal axis of the tail part and thereby an essentially concave upper contour and an essentially convex lower contour with transition contours at the head - and tail end is formed.

The previously common form of a brake lever for bicycle belts or the like with a coaster brake device is made by punching from strip material, the levers at right angles across from the Tape are punched out and are each arranged in pairs in a centrally symmetrical manner. With every punch ι j stroke, four brake levers are punched out at the same time.

This known form of a brake lever is, in contrast, for the production by a total cheaper flat-fitting punching is not suitable

The invention is based on the object of providing a brake lever suitable for sheet-metal punching to train initially mentioned type in terms of its contour design so that he at The greatest possible material savings, taking into account the existing conditions, such as bicycle frames, Quality, material strength and processing options, has the same or even higher strength

It is true that a brake lever has become known that partially overlaps on the top and bottom has similar contours These contours of the brake lever are not, however, by relocating the to obtain one contour opposite the other, d. H. such a lever is known in its contours Cannot be produced by full-surface punching. The issues discussed in the present invention with regard to the strength of the workpiece are in no way mentioned in the known brake lever (AT-PS 66 577).

Furthermore, there are already processes for edge-fitting punching of core sheets for electrical devices known (US-PS 13 39 990), or also for the production of fittings, but which also have the The strength of the respective workpiece has not been dealt with in any way (GB-PS 2633 / 1902). In this respect, these references do not make any reference to the teaching of the invention Subject of the application to give now brake levers for bicycle hubs based on the principle of surface locking To produce punching. w

The object underlying the invention is achieved in that the brake lever upper contour and lower contour over most of their length - as known from another context - are congruent and parallel to each other in a longitudinal axis of the tail part that runs through the bandage screw hole and is parallel to the lower contour are shifted at a small acute angle of displacement inclined displacement direction, the brake lever contour on the head part is essentially formed by part of a bo head circle with a radius corresponding to half the distance between the upper contour and the lower contour along the displacement in said direction of displacement, with tangentially adjoining in towards the tail portion to one another diverging verlau- t, ^r> fenden straight portions, of which the straight section is bent forming a, a part of the contour and in a - as seen in the installation position of the lever - horizontal portion for trusses end hi n and that the other straight section, which is part of the upper contour, is followed by a segment of a circle with the radius of the tip circle and a center distance from this in the direction of displacement corresponding to the tip circle diameter, but with a convex design, the upper contour having a section that adjoins this circle segment approximately tangentially and in the direction of the bandage-side end, running at an acute angle to the horizontal part of the lower contour, continues in a section parallel to the lower contour, furthermore the drum-side end part is made up of one that is essentially perpendicular to the horizontal part of the lower contour and one that runs at an acute angle, upwardly directed end edge composed

With this configuration, it is possible to use brake levers for bicycle hubs with a back pedal braking device Consideration of the requirements regarding material strength, Processing option and attachment of the brake lever to the bicycle frame with optimal Establish material utilization by surface-locking punching.

Further developments of the basic idea of the invention are characterized in the subclaims

The invention is described below with reference to the prior art and a number of exemplary embodiments explained in more detail with reference to the drawings It shows

F i g. 1 shows a brake lever according to the prior art in the assembled state with a bicycle hub and Partial view of the bicycle frame in the side view,

F i g. 2 shows a view of the brake lever according to the prior art according to FIG. 1,

3 shows a schematic representation of the for the Brake lever design important influencing variables,

F i g. 4 shows the illustration of a brake lever according to the invention on the one for punching the lever provided tape material with an explanation of the necessary to determine the optimal width of the tape essential influencing factors,

F i g. 5 an embodiment of a brake lever according to the invention,

F i g. 6 the determination of two further brake lever contours according to the invention with related ones Schematic representation of the material stresses occurring for the various lever forms,

F i g. 7 the example of the construction of a further brake lever contour according to the invention,

8 a further embodiment for the construction of a brake lever contour accordingly the representation according to FIG. 7, but with a lower material thickness,

9 shows the embodiment of a brake lever according to the invention, in which the drum-side opening is formed by a slit open at an angle towards the end,

F i g. 10 shows a variant embodiment of the brake lever for FIG. 9, but with less material thickness,

F i g. 11 shows the stress distribution of the lever shapes according to FIGS. 9 and 10 in comparison with a lever according to the state of the art,

12 shows a further embodiment of the brake lever designed according to the invention with opposite the aforementioned embodiments reduced punching stroke, which is understood to mean the material feed is,

13 shows a brake lever design corresponding to FIG. 12, but with a lower material thickness,

14 shows a schematic representation of the length along the brake lever according to FIGS. 1 and 2 as well as 12 and 13 occurring material stresses,

Fig. 15, the c-making proper brake lever design with smaller punching stroke and an embodiment of the trusses side opening than at the end open towards the slot,

FIG. 16 shows an embodiment variant according to FIG. 15, but with compared to this lower strength of the brake lever,

17 shows a schematic representation of the material stresses the brake lever according to the Fi g. 1, 15 and 16. r,

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

In Fig. 2 is the prior art brake lever as shown in FIG. 1 appears, again separately jo shown. The opening 7 on the bandage side is designed as a bore for receiving a screw. the Hub-axle-end hole is designed as a profile hole 8 for non-rotatable attachment to one corresponding approach of the lever cone (part 5 in J5 Fig. 1) to thereby reduce the braking force from the lever cone to be transferred to the brake lever. The profile hole 8 is attached so that its center point with the center point the hub axle coincides

From FIG. 2 it can be seen that a brake lever with such an outer contour cannot be produced by surface-locking punching. Rather, the punching operation of these brake levers has so far been carried out in such a way that the levers are punched out in pairs symmetrically to a point of symmetry from the strip of material, the respective tool preferably being designed for punching out four levers during a punching stroke. The levers are in such a way that the end on the hub axle side with the profile hole alternates on the right and left edge of the material bandE 211 He * ⁷ ** !! come * where ^ ** '^ i ** two longitudinally extending parts of the brake lever are arranged approximately parallel to each other. According to the conventional view, this design and manufacture of the brake levers resulted in very good material utilization and efficient manufacture, but, as will be shown below in connection with exemplary embodiments of the invention, can still be improved quite decisively.

In FIG. 3, certain shape conditions and influencing variables for the design of the brake lever are compiled as a flat, stamped part with regard to their geometrical relationships and will now be explained below. The distance between the center M * of the hub axis and the center Mb of the drum screw is fixed by the structural dimensions of the bicycle frame and the size of the braking forces to be transmitted. This distance is denoted by R ' . As a result of the frame design, the two center points cannot be on a horizontal plane, but when the lever is installed, the center Mb must be located below the center Ma . For the horizontal lever part at the end of the drum, 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 stamping and strength considerations and cannot be below a certain size. The diameter s of the tip circle at the lever (center point Ma) corresponds to the punching stroke or material feed and is determined by the means selected for the transmission of the torque from the lever cone to the brake lever. R denotes the distance between the horizontal lower lever edge Ku and the center Ma and ρ denotes the distance between the imaginary upper lever edge, which only coincides with the actual edge above the opening 7 on the drum side, from the center Ma . This imaginary edge is shown in FIG. 3 Ko called. By defining the sizes s, R ', f, c, R and ρ, the shape of the brake lever is essentially determined. The invention now shows possibilities of optimizing material consumption and strength ratios.

In Fig. 4 shows the considerations that lead to the determination of the optimal bandwidth B. In this figure, the brake lever is shown in its position on the strip material used for production. One can see very clearly from this 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

together in the upper part from the line ^ and in

lower part following on from the considerations in FIG. 3 from the segment c · cos λ. λ is the inclination of the horizontal lever part (upper edge Ko or lower edge Kt /) in relation to the punching direction (parallel to the band boundaries 19 on both sides). The angle β denotes the inclination of the connecting line between the center point Mb of the opening on the drum side and the center point Ma 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 distance of the band is thus obtained from the relation R '■ sin (λ + ß). In order to limit the number of influencing variables, the value ρ was also expressed as a function of the influencing variables c and /. This then results in i

sin χ =

sin /> '=

f + c

S + f R '

The quantity ρ itself was thus defined as f + c . After the determining quantities in the equation for the bandwidth, which result from the above considerations as

B = -ψ + R '■ sin (α + β) + c cos *
results can be determined constructively, can also be:

this formula provides the optimal range for the manufacture of the lever in surface-locking punching be determined.

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

Reducing R ' in size, which would result in a smaller bandwidth and thus material savings, is to be rejected because the forces on the bicycle frame are then greater.

It would be possible to reduce c and /, but this is done in terms of punching technology with regard to the necessary remaining wall thickness limited. Somewhat more favorable conditions can be created here if instead of the drum side A slot is provided at this point in the bore or opening. Embodiments of the brake lever with a slot are shown below with reference to FIGS. 9 and 10 as well as 15 and 16 explained.

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

The lower limit of the dimensioning of the material thickness b results from the necessary flexural strength, buckling strength and shear strength when the torque is transmitted from the lever cone to the frame.

In Fig. 5 shows an exemplary embodiment of the subject matter of the invention. Because the transfer of the Braking force from the lever cone to the brake lever in different ways and not just through a profile hole can take place, in which a bandage screw engages, this option was used in FIG. 5 and not discussed further in the following explanations of exemplary embodiments of the invention. It should however, it should be noted that at a transition from the profile hole according to Figure 2 to a Bore with an inner knurl of the hub axle end part of the lever can be kept very small (Diameter of the so-called Kqpfkreises), what about a small punching stroke (tip diameter = punching stroke) can lead to further material savings. In detail here are material savings and Weighing up the durability and manufacturing costs for the knurling in the brake lever against each other.

The brake lever according to FIG. 5 can be produced by flat-fitting punching. The lever contour of the upper edge 9 is repeated, but offset in the longitudinal direction, on the lower edge 10. The contour runs out towards the bandage end of the lever in a horizontal straight line. This lever can be arranged accordingly on a strip of material, the lateral boundaries of which run parallel to the punching direction Sr shown in FIG. The end edge of the brake lever on the bandage side is composed of an essentially vertical section 11 and an upwardly directed section 12 which runs at an acute angle to the horizontal. The corresponding arrangement of the section 12 parallel to the punching direction is essential, since in this way the bandwidth corresponding to the cut corner and thus the corresponding material is saved. The contour of the lever according to FIG. 5 is composed in detail of a peripheral part of the tip circle 13, which is tangentially followed by a substantially horizontal section 14 at the upper edge. At the upper edge 9, the horizontal section 14 goes into a kink

^Λ > arc 17 over, which corresponds approximately to the arc 13 in terms of radius. A straight section 27 or 18 adjoins the arch 17 at the upper edge and extends to the lever end on the bandage side. This brake lever shape results in relation to the brake lever shape

ίο according to Figure 2 according to the prior art a Material savings of 34.85%. - The levers shown in the figures are to scale and in Scale 1: 1 shown—

In Figure 6, a possibility will now be explained, the

ι s to find the most favorable lever shape for 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 Mb of the drilled hole or opening 7 on the drum side, the necessary lever height at constant bending stress is plotted along the horizontal straight line Ku over it. This curve is denoted by 20. According to the selected conditions, the center Ma and thus the tip circle 13 are also defined for the center Ms. 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, curve 20 can be used to determine the upper edge of the brake lever, which then results in a brake lever shape D (see table at the end of the description). In the lower part of FIG. 6 the bending stresses σ that occur are now plotted in% of the maximum value. From this it can be seen that the for

j5 comparison used lever shape A (construction according to the prior art Fig. 2) has an unfavorable stress distribution, but that shape D also shows this unfavorable stress distribution, only at a different point. It is now possible to find another brake lever shape , in that, starting from the tip circle 13 'vertically downwards, the bending stress values resulting from the curve 20 are plotted (curve 21). In this way one can arrive at the brake lever shape according to E. However, this brake lever shape is not an optimum either, as can be seen from the corresponding stress distribution. Here, a stress peak results in the vicinity of the stress peak of the lever from FIG. 2.
In Fig. 7 a possibility is now explained

so by mediating between the curves 20 and 21 to find a lever shape that is much more favorable in terms of stress distribution. The mediation takes place in such a way that, starting from the curve 20 and 21, parallels to the punching direction Sr are drawn (parallel straight line 22) which intersect the curve 21 at points 23 and curve 20 at points 24. If now the distance between the points 23 and 24 on the respective straight line 22 is halved and from the midpoints 25 occurring in each case to

^If the distance ^ is plotted on both sides, then the

mediated curves 21 'and 20'. If the lever contour is now fixed as a tangent to these curves, it results as shown in FIG. 6 shows a very favorable b5 stress distribution, the maximum values of which are only 64% of the levers according to forms A, D and E. At the same time, the material savings of 34.85% compared to Form A are significantly more favorable.

As shown in FIG. 6 can be seen, the bending stress of the lever shape F is according to FIG. 7 only about 64% of the maximum bending stress in the case of lever type A according to the prior art (FIGS. 1 and 2). However, since the lever shape A is not overloaded with regard to the bending stresses, a brake lever shape can be sought which has approximately the same bending stresses as lever shape A while further saving material. The same considerations as shown in FIG. 6 were employed, can now, in order to better utilize the material strength, be carried out with a brake lever whose material thickness b is only 3 mm instead of 4 mm as in FIGS. 6 and 7 is. This then leads, via the corresponding steps, to a lever according to FIG. 8, which is also created by arranging the curves 20 and 21. By comparison with FIG. 7 shows that this lever has a greater height in the area of the greatest bending stresses. The maximum bending stress of lever type A (state of the art), based on and designated 100%, results in comparison with this for the one in FIG. 8 / a maximum bending stress of about 85% and a material saving of 51.14% compared to the cost of materials according to the prior art. The bending load on the lever is still 15% less than that of lever type A.

In Fig. 9 (lever type K) a lever was designed in which the lever end heights / and c (minimum distances between the upper edge 9 and lower edge 10 from the center Mb of the opening on the drum) were reduced so that the bending load remained approximately the same as with the lever 8 (max. bending stress i.e. about 85% of the bending stress in lever form A) the greatest possible material savings are achieved. 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. The selected lever strength of ft = 4 mm results in a material saving of 41%.

In FIG. 10, a lever shape is shown in which a lever thickness b = 3 mm is assumed. In this case, even if bending stresses up to the same size as with lever type A are permitted, the lever end height must be increased slightly due to the lower material thickness, so that for f + c there is 12.75 mm. As a result of the angles <x and β , which change with the size of / + c , a bandwidth of 67.5 mm results in this case. Nevertheless, by reducing the material thickness and making better use of the bending load, a maximum material saving of 54.8% compared to lever type A can be achieved with the same maximum bending load.

In both cases of the lever forms according to FIG. 9 and 10, the opening on the bandage side is no more than Bore or opening 7, but designed as a slot 7 '. This is the prerequisite for the Reduction of the lever end height in order to avoid wall thicknesses that can no longer be produced in the punching process obtain.

In FIG. 11 is the distribution of stress σ * the Lever shapes according to Fig. 9 and 10 compared to Prior art shown From this stress distribution it can be seen that a relatively good Material utilization is present

In FIGS. 12 to 14, lever shapes and stress distribution in brake levers according to the invention are shown, assuming a smaller tip circle 13 of only 29 mm. In these levers, however, it differs from the FIGS. 9 and 10 again a bore is provided as an opening 7 on the drum side. As a result, a certain minimum dimension for the lever end height f + c cannot be fallen below. The size f + c was assumed here to be 13.5 mm. The design equation for the bandwidth then results in one of β = 74 mm and that used in FIG

ίο material thickness of ft = 4mm a material saving of 41.8%.

The considerations for the brake lever according to FIG. 13 were made with otherwise the same sizes, only with the smaller material thickness of i = 3 mm. This results in a somewhat modified brake lever shape compared to FIG. 12 (brake lever shape M), which results in better utilization in terms of tension (can be seen from FIG. 14) and greater material savings, namely 56.5%. The brake lever shape according to FIG. 13 is designated with form JV

In the Fi g. 15 to 17 are still brake lever forms and the associated stress distributions are shown, an attempt being made as shown in FIGS. 9 and 10 to reduce the lever end height.

In FIG. 17 results for a lever end height / + c of 11.5 mm an optimal bandwidth B of 66.5 mm, the tip diameter and thus the punching stroke s as in the previous FIGS. 12 and 13 should be 29 mm. The lever shape O in FIG. 15 with the material thickness b = 4 mm results in a material saving of 47.85%, whereby, as can be seen from FIG. 17, the maximum bending stress is 94.5% of the lever shape A.

In the case of the lever shown in FIG. 16, a lever end height f + c of 13 mm was assumed.

This increase results from the reduction in material thickness b to 3 mm due to the condition that the maximum bending stresses occurring in the current lever shape A (state of the art) should not be exceeded. This results in an optimal bandwidth of ß = 70mm and a material saving of 58.8%. From Fig. 17 it can be seen that with this lever shape P a good stress distribution with maximum material utilization is achieved. The maximum stresses that occur in lever form A are not exceeded.

The in the F i g. 9 and 10, 12 and 13 as well as 15 and 16 Brake lever shapes shown are, as far as the drawn curves 20 and 21, the upper edge 9 and the Tangent lower edge 10, according to the method shown in FIG. 6 was explained, constructed provided these curves If further away from the upper or lower edge, the edges are blurred, as in FIGS. 7 and 8 explained set

The lever shape C according to FIG. 5, F according to "P i g. 7, / according to FIG. 8, K according to FIG. 9, L according to FIG. 10, M according to FIG. 12, N according to FIG. 13 and A according to FIG. 15 are essentially similar. The The contour of this brake lever is essentially formed at the hub axle end by the part of the tip circle circumference with a radius corresponding to half the punching stroke 9), which diverge from one another, and then close along the upper edge 9

b5 with a kink the part of a circle segment 17 at,

which has the same radius, namely ij as the tip circle 13 The lower edge 10 is then applied

the section 26 continues with a kink in a horizontal section 16 towards the end of the bandage. At the The upper edge 9 adjoins the circular arc 17 approximately tangentially and at an acute angle to the horizontal running a section 27, which then with a kink in the horizontal to the lever end extending section 18 connects. The bandage-side termination of the lever has a substantially vertical section 11 and an acute angle to Horizontal section 12, which is provided in each case to reduce the bandwidth. 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. The section 16 corresponds to the section 18 at the upper edge the lower edge, the section 16 being longer than the section only because of the offset in the longitudinal direction 18 is. It also corresponds to the section 27 at the upper edge to the section 26 at the lower edge, wherein here the angle to the horizontal, but also the length are the same. It still corresponds to Arc 17 to the tip arc 13 on the

Lower edge. This enables these levers to be manufactured using the surface-locking stamping process

In the case of the lever shape P , a section 28 is provided at the top and a section 29 at the bottom, which is horizontal with the section 27 of the upper edge and section 26 of the lower edge (see FIG encloses a smaller angle as the sections 26 and 27 and then merges with a further bend into the horizontal 18 and 16, respectively. 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 Sr. Otherwise, the section 12 is also arranged parallel to the punching direction Sr

The table below provides a comparison of the various lever types discussed refer to:

Lever shape

Shown in Fig.

volume

(enr ")

Material savings (related to A)

Lebel strength lever end

hole

(mm)

slot

1 and 2

9
10
12th
13th
15th
16

14.79 9.636 9.636 7.227 8.58 6.68 8.60 6.43 7.70 6.09

34.85

34.85

51.14

41

54.8

41.8

56.5

47.8

58.8

X
X
X
X

X
X

X
X

In addition 8 sheets of drawings

Claims (7)

Patent claims: 1. Brake lever for bicycle hub with coaster braking device to support the braking torque of the lever cone of the bicycle hub on the bicycle frame with a hub axle-side, widened head part with an opening at least for inserting the hub axle and a bandage-side tail part with an opening for the bandage screw, the center of gravity of the head part of the brake lever is offset with respect to the longitudinal axis of the tail part and thereby an essentially concave upper contour and an essentially convex lower contour with upper passage contours at the head and tail end is formed, characterized in that the brake lever upper contour (upper edge 9) and the lower contour (lower edge 10 ) are congruent over most of their length - as known from another context - and parallel to one another in a longitudinal axis of the tail part running through the bandage screw hole (opening 7) and parallel to the lower contour (lower edge 10) under a small pointed en 2 ^r i displacement angle (α) inclined displacement direction, the brake lever contour on the head part essentially from part of a head circle (13) with a radius corresponding to half the distance between the upper contour (upper edge 9) and the lower contour jo (lower edge 10) along the Shift is formed in the mentioned shifting direction, with tangentially adjoining straight sections (14, 26) which diverge towards each other in the direction of the tail part and of which the straight section forming part of the lower contour (lower edge 10) is bent and is in a - Seen in the installed position of the brake lever - the horizontal section (16) continues towards the drum-side end and that a circular section (17) with the radius of the tip circle (13) is located on the other straight section (27), which is part of the upper contour (upper edge 9). and a center distance from this in the direction of displacement corresponding to the tip diameter (s), but kpnvexer 4 ^r > training adjoins, wherein the upper contour (upper edge 9) has a 'this circular segment (17) approximately tangentially adjoining section (27) and in the direction of the bandage-side end, at an acute angle to the horizontal part><> (16) of the The lower contour (lower edge 10) continues in a section (18) parallel to the lower contour (lower edge 10), the bandage-side end part also being composed of an essentially perpendicular to the horizontal part (16) of the lower contour (lower edge 10) π and an acute angle extending, upwardly directed end edge (12) composed. 2. Brake lever according to claim 1, characterized in that one of the center point (Mb) of the wi bandage-side opening (7) of the brake lever (1) proceeding to the elongated part (16) of the lever lower contour (16) adjacent to this opening. Lever edge Ku, lower edge 10) parallel, horizontal line opposite the center point (Ma) of the opening on the hub axis by the sum of the minimum distance (c) of the center point (Mb) from the lever lower contour (lever edge Kn, lower edge 10) and twice the minimum distance ( f) is offset from the upper contour of the lever (lever edge Ko, upper edge 9) to the lower contour (lever arm Ku, lower edge 10) of the brake lever 3. Brake lever according to one of claims 1 or 2, characterized in that the upper contour (lever edge Ko, upper edge 9) and the lower contour (lever edge Ku, lower edge 10) consist essentially of straight parts on the drum side. 4. Brake lever according to one of claims 1, 2 or 3, characterized in that the upper contour (lever edge K _a upper edge 9) and the lower contour (lever edge Ku, lower edge 10) in the region of the drum-side bore (opening 7) each have two straight sections have a separating kink. 5. Brake lever according to Claim 1 or one of the following claims, characterized in that the opening (7) on the bandage side as an end edge (section 12) extending from the slot (7 ' ) at an acute angle to the horizontal section (16) of the lower contour (lever edge Ku lower edge i0) ) is designed with a semicircular slot base 6. Brake lever according to claim 5, characterized in that adjacent to the acute angled to the horizontal sections (26 and 27) on the lower contour (lever edge Ku, lower edge 10) and on the upper contour (lever edge Ko, upper edge 9) flatter, also at an acute angle to Horizontal sections (28 and 29) are provided which merge into the horizontal (sections 18 and 16) towards the end on the bandage side. 7. Brake lever according to claim 1 or one of the following, characterized in that the optimal bandwidth (B) according to & the relationship in the production by surface-locking punching