The present invention relates to an adjustment tool for bicycle rim brakes of the kind comprising a pair of opposed brake blocks arranged for engagement with opposite sides of a bicycle wheel rim, the tool comprising a pair of interconnected opposed jaw mem- bers, means for securing the jaw members to the wheel rim with internal sides of the jaw members clamping against said opposite rim sides and means for subse- quent positioning of the brake blocks with a defined radial position and a prescribed angular orientation of their rim engaging brake surfaces with respect said opposite rim sides.

For. bicycle rim brakes of the kind defined, exam- ples of which are the well-known"Cantilever"and"V- Break"types, it is conventionally prescribed by manufacturers, in order to avoid vibration and insuf- ficient brake effect and excessive noise, that the brake blocks must be mounted with a so-called"toe- in"angular orientation with respect to the opposed brake block contacting sides of the bicycle wheel rim, such that frictional engagement between a brake block and the wheel rim is initially made at the front end of the brake block with respect to the di- rection of rotation of the wheel. Frequently the brake adjustment required to provide the prescribed angular orientation has been performed solely by eye judgment, which may be a cumbersome and time- consuming trial and error process, however, typically requiring a number of attempts with varying results.

To facilitate correct angular brake block setting a relatively simple adjustment tool known from GB-A-2

201 943 comprises a template with a raised ridge at its rear end. In use this template must be manually held between the wheel rim side and the brake block to be adjusted In DE-A1-44 43 601 and US-A-5 499 698 clamping ad- justment tools of the above-defined kind is dis- closed, which may be secured in a fixed position on the bicycle wheel rim by means of the opposed jaw members, and wherein positioning means comprises short nose members projecting from the jaw members for supporting the rear end only of the brake block with a clearance with respect to the wheel rim side to obtain the prescribed"toe-in"angular orienta- tion. In use of these tools the front end of the brake block will be adjusted into contact with the wheel rim side in a position close to its operative brake position. This is inconvenient, since it is normally preferred to mount bicycle rim brakes with the brake blocks assuming their inoperative released positions with a defined minimum clearance from the wheel rim throughout their length.

On this background it is the object of the inven- tion to provide a further improved adjustment tool of the clamping type, by which the inconvenience in use and the functional drawbacks of the prior art brake adjusters outlined above are eliminated or at least substantially reduced.

According to the invention an adjustment tool for bicycle rim brakes of the kind defined is character- ized in that said brake block positioning means com- prises a brake block contacting surface formed on an external side of each jaw member opposite the inter- nal side thereof and having a length corresponding to

a substantial part of the length of a brake block for positioning the brake blocks in. released positions with a clearance from the opposed wheel rim sides.

The adjustment tool according to the invention may be easily and reliably secured in a fixed position with respect to the bicycle wheel rim. In the mounted position of the adjustment tool the brake blocks on either side of the bicycle wheel rim is simply placed in contact with the contact surfaces provided by the external sides of the jaw members to obtain correct setting of the angular"toe-in"orientation as well as radial positioning to prevent the brake blocks from engagement with the tyre mounted on the wheel rim during subsequent use of the brakes. In the ad- justed positions the brake blocks may be safely con- nected with the brake control mechanism before re- moval of the adjustment tool.

Preferred and advantageous embodiments of the ad- justment tool are stated in the dependent claims. In a particularly preferred embodiment, a very simple and inexpensive adjustment toll is obtained in that the jaw members are formed by branches of a unitary tool member of generally U-shaped cross-section, said securing means comprising screw means engaging said branches outside wheel rim contacting parts of the jaw members.

In the following the invention will be explained in further detail with reference to the accompanying drawing, in which fig. 1 is a simplified cross-sectional view of an embodiment of an adjustment tool according to the in- vention in its position of use secured to a wheel rim of a bicycle;

fig. 2 is a plan view of a jaw member in the em- bodiment shown in fig. 1 from the external side thereof; fig. 3 is a sectional view along the section line III-III in fig. 2; fig. 4 is a perspective view showing the intercon- nected jaw members of the embodiment in fig. 1 formed by a unitary U-shaped tool member; fig. 5 is a perspective view of the adjustment tool in its position of use; and fig. 6 shows a peg-like embodiment of the adjust- ment tool with the law members formed by intercon- nected spring-biased peg members.

In the embodiment shown in figs. 1 to 5 the ad- justment tool comprises a. unitary tool member 1 of generally U-shaped cross-section with branches 2 and 3, which at their distal ends form jaw members 4 and 5. By means of a manually operated screw member such as a conventional wing screw 6 the branches 2 and 3 may be moved in directions towards and away from each other to bring internal sides 7 and 8 of the jaw mem- bers 4 and 5 into releasable clamping engagement with opposite side 9 and 10 of a conventional bicycle wheel rim 11.

For correct positioning of the adjustment tool in the radial direction of the wheel, such that brake blocks 12 adjusted by means of the tool will be pre- vented from engagement with a tyre 13 mounted on the rim 11 during subsequent use of the rim brake, first guide means is provided in the form of guide ribs or flanges 14 projecting from the internal sides 7 and 8 of jaw members 4 and 5 close to their external pe- ripheral edges for engagement with the external pe-

ripheral edges 15 and 16 of the wheel rim 11.

In accordance with the invention a brake block contacting surface 17 is formed by a depression in the external side of each of jaw members 4 and 5 and, in use of the adjustment tool, a brake block 12 to be adjusted, is positioned in close contact with this surface as seen in fig. 1. To confine the radial po- sition of the brake block 12 in alignment with one of the opposite sides 9 and 10 of the wheel rim 11 and thus prevent the brake block from getting into con- tact with the tyre 13 during subsequent use, as de- scribed above, second guide means is provided in the form of guide ribs or flanges 18 projecting from the external side of each of jaw members 4 and 5.

As shown in figs. 4 and 5 the first guide means may preferably be formed by distinct projecting guide ribs or flanges 14 at either end of the internal side of each jaw member to extend over a limited part only of the length of the jaw members 4 and 5 for easy ad- aptation of the use of adjustment tool to wheel rims of varying diameter. The second guide means formed by projecting ribs or flanges 18 may as shown in fig. 2 extend throughout the length of each jaw member, but may alternatively comprise distinct projections ex- tending only over a limited part thereof.

As shown in fig. 3 the brake block contacting sur- face 17 on the external side of each of jaw members 4 and 5 may have a length substantially equal to the entire length of a conventional brake block 12 to be contacted by the brake block throughout the length thereof. The length of the contacting surface may al- ternatively, however, be somewhat shorter than the length of the brake block, as long as it supports the

brake block over a substantial part of its length sufficient to avoid tilting of the brake block 12 when positioned in contact with the contacting sur- face 17.

As further illustrated in fig. 3 adjustment of the brake block 12 by contact with the brake block con- tacting surface of a jaw member to setting of the prescribed angular"toe-in"orientation is obtained by a wedge-like cross-sectional profile of the wall of the jaw member 4,5 with a wall thickness increas- ing from a front end 19 to a rear end 20 of the jaw member 4,5, with respect to the direction of rotation of the wheel rim indicated by an arrow 21, to provide to provide an increase of the clearance between the brake block and the wheel rim side 7,8 from the front end 19 to the rear end 20 by 1 to 1.5 mm for a typical brake block length of 70 mm corresponding to a prescribed"toe-in"angle v typically in the range from 0.8 to 1. 2°.

In the embodiment shown in figs. 1 to 5 the uni- tary adjustment tool may preferably be manufactured as an inexpensive moulded one-piece component of a suitable plastic material.

In the rather schematic view in fig. 6 an alterna- tive embodiment is shown, wherein the adjustment tool is made in a form like a clothes-peg with the jaw members 4'and 5'formed by end sections of pivotally interconnected peg members 22 and 23, which are spring-biased towards the clamping position of use as illustrated by arrows 24. The adjustment tool in fig.

6 is operated by squeezing opposite ends of the peg members 22 and 23 against the spring-bias to spread the jaw members. After positioning of the jaw members on opposite sides of a wheel rim the jaw members are clamped against the wheel rim by releasing.. the oppo- site ends of the peg members 22 and 23.