WO1995005968A1

WO1995005968A1 - Device for measuring the position of the chain drive of a bicycle

Info

Publication number: WO1995005968A1
Application number: PCT/EP1993/002244
Authority: WO
Inventors: Robert Schmitt
Original assignee: Robert Schmitt
Priority date: 1993-08-20
Filing date: 1993-08-20
Publication date: 1995-03-02
Also published as: EP0664755A1

Abstract

The invention concerns a device for measuring the position of the chain drive of bicycles, etc., having a bottom-bracket crank-axle housing (2) designed to hold the crank-axle assembly carrying the pedal cranks and the front-sprocket assembly (8). The measurement device includes a spindle (4) which can be fixed in the crank-axle housing (2) so that one end (6) of the spindle projects out beyond the housing, this end of the spindle matching in design and dimensions the corresponding end of the crank axle fitted. Mounted on this end (6) of the spindle is the front-sprocket assembly (8). A first sliding measurement head (26) is fitted with a pointer (28) mounted so that it can be pointed towards the front-sprocket assembly (8). A second sliding measurement head (30) is fitted with a pointer (32) mounted so that it can be pointed towards the rear-sprocket assembly. A graduated scale (64) indicates the offset between the front-sprocket assembly and the rear-sprocket assembly. The graduated scale (64) is preferably calibrated so that the required crank-axle length can be read off directly.

Description

Device for measuring the chain drive of bicycles

The present invention relates to a device for measuring the chain drive of bicycles, training bicycles and the like, with a bottom bracket housing for receiving the bottom bracket assembly that carries the pedal cranks and the front sprocket.

The perfect functioning of a chain drive for bicycles and the like depends in a very special way on the fact that the front sprocket is exactly aligned with the rear sprocket, both of which can be single or multiple sprockets. In modern gear shifts, in which multiple sprockets are provided at the front and rear, for example, a preferred pair of sprockets, in which one wants to have an ideal chain line, is exactly matched to one another. directed. This alignment is currently carried out more or less by eye in such a way that, with the rear wheel installed, from different bottom bracket arrangements with different wavelengths, the one with the desired alignment is selected. To do this, several bottom bracket arrangements must generally be installed one after the other, chains applied and the drive actuated until the optimal constellation is found. This applies in particular to retrofitting or repair operations, in which deviations from the ideal chain line can result from the fact that new gear pairs are combined with one another, that the front sprockets with different forces are pressed onto the conical square of the bottom bracket shaft, etc. However, it also applies to series production, in which deviations from the ideal chain line, for example due to inaccuracies in the bicycle frame, dimensional deviations of the bottom bracket shell, different forces when the front ring gear is pressed onto the bottom bracket shaft, different designs of this bottom bracket shaft roughly corresponding to a Western European one Norm or a Japanese norm etc. may occur. Because of the difficulties described above, the assembly of the chain drive is still cumbersome and therefore time-consuming and expensive, and in many cases an ideal chain line and thus perfect functioning of the chain drive cannot be achieved at all.

It is the object of the present invention to improve the assembly of the chain drive of bicycles and the like, in particular the alignment of the front and rear sprockets with respect to one another.

This object is achieved by a device with the features described in claim 1. This device has a measuring axis which can be clamped in the bottom bracket housing and has an axis end which projects axially beyond the bottom bracket housing and which essentially corresponds in design and dimension to the corresponding shaft end of the intended bottom bracket arrangement; When the rear wheel is mounted, the front sprocket is placed on this axle end with the pressing force which is also provided for the final assembly of the chain drive. The front sprocket then has the exact position relative to the rear sprocket that would have resulted if the intended bottom bracket arrangement had been installed. The setting of the front sprocket to the rear sprocket can now be determined in a simple manner by aligning the first slide with respect to the front sprocket and the second slide with respect to the rear sprocket, preferably in accordance with the preferred pairing of sprockets. The relative position of the two carriages to one another and thus the position of the front ring gear to the rear ring gear can now be read on the measuring scale arrangement.

The measuring scale arrangement can have a suitable type of division, which makes it possible to determine the possible offset of the two toothed rings from one another and to take the necessary few measures to compensate for this offset. The usual measure to compensate for this misalignment is to select the bottom bracket arrangement that guarantees the ideal chain line from a number of bottom bracket arrangements with different, predetermined wavelengths with a narrow length gradation. In a preferred embodiment of the invention, the measuring scale therefore has a division which indicates the length dimensions of the available bottom bracket arrangements. If the front sprocket is offset from the rear sprocket, the measuring scale Order to read directly the bottom bracket type that should be mounted.

In principle, the two slides can be mounted and actuated independently of one another. Such an embodiment has the advantage that, once the second slide has been aligned with the rear sprocket, the front slide can be adjusted as desired without the second slide having to be readjusted. In terms of design, however, there are advantages in another embodiment, in which one of the slides is mounted so as to be adjustable directly relative to the measuring axis and the other slide is mounted so as to be adjustable relative to the first slide. In the case of a constructive embodiment, it is provided that on the axis end of the measuring axis facing away from the projecting axis end there is attached a support arm which is at right angles thereto and on which at least the first slide is adjustably mounted. The second carriage is then adjustably mounted on the first carriage, for example, and in addition to being guided on the first carriage, it can also be guided on the support arm. This arrangement ensures that the device according to the invention is extremely robust and can withstand a rough workshop operation.

The measuring scale arrangement preferably comprises a measuring scale arranged on one of the carriages and a pointer device arranged on the other carriage.

In order to be able to take different bottom bracket housing lengths into account in a simple manner, several measuring scale arrangements are provided according to the invention, which are matched to different bottom bracket housing lengths. In this case, for example, several measuring scales can be provided, which are arranged on the measuring scale surface at the same time, whereby these differ, for example, in color distinguish, or which are arranged offset in the circumferential direction on a round rod-shaped scale carrier, so that they can be brought into their operating position by rotating the scale carrier. In another embodiment of the invention, several interchangeable measuring scales are provided. A further embodiment provides that a single measuring scale is arranged on the scale carrier, which interacts with different pointer devices which are assigned to the most varied of bottom bracket shell widths and which can be adjusted into an operating position.

In a preferred embodiment of the measuring axis, it is provided that the end facing away from the projecting axis end of this measuring axis carries a fixed flange which bears against the associated end face of the bottom bracket housing, and that the measuring axis carries a thread in the region of the projecting axis end on which a screw nut or a screw ring bearing against the other end of the bottom bracket housing can be screwed on. The measuring axis is preferably rotatably mounted in the support arm and equipped with an actuating button for turning. The measuring axis is mounted in such a way that it is inserted into the bottom bracket housing from the side facing away from the front sprocket until the fixed flange rests on the bottom bracket housing. The screw nut is then threaded onto the protruding end of the axle and screwed onto the thread. The screwing-on process can be facilitated by holding the screw nut firmly, for example with a wrench, and turning the actuating button until the screw nut is firmly attached to the bottom bracket housing. Further details, advantages and features, which relate in particular to the construction of several exemplary embodiments of the invention, result from further subclaims, from the following description and the drawing, to which express reference is made to the disclosure of all details not described in the text. Show it:

Figure 1 shows a device mounted on a bicycle frame according to the invention in a cross section.

FIG. 2 shows the device according to FIG. 1 in a view corresponding to arrow II;

FIG. 3 shows an illustration approximately according to FIG. 1 on an enlarged scale.

4, 4a, 4b show an illustration approximately according to FIG. 3 of another exemplary embodiment.

Fig. 1 shows a bottom bracket housing 2 of a bicycle frame in a cross section. A measuring axis 4 is inserted into the bottom bracket housing 2. The measuring axis 4 has an axle end 6 which projects axially beyond the bottom bracket housing 2 and which essentially corresponds in design and dimension to the shaft end of a bottom bracket arrangement, so that a front sprocket assembly 8 can be placed on the axle end in the same way as with a bottom bracket shaft end . In the present exemplary embodiment, the front sprocket arrangement 8 is combined with a pedal crank 10 to form a structural unit.

The axle end 6 is designed in the manner known for bottom bracket shaft ends as a square 12, the boundary surfaces of which converge towards the axle end; the crank 10 is provided with a corresponding square recess, which can be pressed onto the square 12. A screw 14 axially screwed into the axle end 6 serves, if necessary, with the interposition of a washer or the like, for locking the pedal crank 10 and the toothed ring 8 connected thereto on the axle end 6.

The measuring axis 4 has at its end facing away from the axis end 6 a fixed flange 16 which bears against the left end of the bottom bracket housing 2 in FIG. 1. In the area in which the measuring axis 4 emerges from the bottom bracket housing on the right side in FIG. 1, it is provided with an external thread onto which a screw nut 18 can be screwed. By screwing on the screw nut until it rests on the right-hand end face of the bottom bracket housing 2 in FIG. 1, the measuring axis 4 can be fixed in a defined position in the bottom bracket housing 2.

The measuring axis 4 is provided at its end facing away from the free axis end 6 with an axis extension 20 which is rotatably mounted in a support arm 22. An actuation button 24 is placed on the end of the axis extension 20, by means of which the measuring axis 4 can be rotated. To assemble the measuring axis, it is inserted into the bottom bracket housing 2 from the left side in FIG. 1, then the screw nut 8 is threaded onto the measuring axis 4 from the right side in FIG. 1 and, for example, by means of a wrench held. By turning the actuating button 24, the screw nut 18 screws onto the associated external thread until the measuring axis 4 is fixed.

As will be explained in more detail with reference to FIG. 3, a first carriage 26 is parallel at the free end of the support arm 22 to adjust the measuring axis 4 adjustable. It carries a pointer 28 which is aligned with the front sprocket arrangement 8 in the example in FIG. 1 with its central sprocket. On the first slide 26, a second slide 30 is also arranged to be adjustable parallel to the alignment of the measuring axis 4. This carries a pointer 32 (see FIG. 2), which can be aligned with a preferred ring gear of the rear ring gear arrangement 34.

A scale arrangement 36 makes it possible to read the relative position of the slides 26 and 30 relative to one another and thus a possible offset of the front sprocket arrangement 8 with respect to the rear sprocket arrangement 34, as will be described in more detail further below.

FIG. 2 shows the arrangement of FIG. 1 in a view corresponding to the arrow II in FIG. 1. The front sprocket arrangement 8 can be seen, which is combined with the pedal crank 10 to form a structural unit, and also a part of the Support arm 22 according to the invention, on whose side facing away from the viewer the first carriage 26 is arranged, furthermore the second carriage 30, which is displaceably arranged on the first carriage 26, with the pointer 32 fastened thereon, and the rear sprocket arrangement 34 1 and 2, the pointer 32 is fastened to the second slide 30 via an elongated hole 38 formed thereon and a fastening screw 40 extending therethrough. This arrangement gives the possibility of adjusting the effective length of the pointer 32 by shifting in the direction of the elongated hole 38 and its setting angle O _' in the chain drive plane and thus aligning it optimally with a sprocket of the rear sprocket arrangement 34. FIG. 3 shows the arrangement of FIG. 1 again in an enlarged view. The same components are each provided with the same reference numerals.

The design of the slides 26 and 30 is described in particular below.

The carriage 26 is an approximately L-shaped block of material, for example made of aluminum or plastic. Its longitudinal leg 26 'is aligned in the direction of adjustment X, i.e. parallel to the measuring axis 4. On the underside of its transverse leg 26 ″, a guide tube 42 is let in, which is displaceably guided in a guide bore 44 formed in the region of the free end of the support arm 22.

An adjusting spindle 46, which is supported on the support arm 22 and can be actuated via a rotary knob 48, is connected to the first carriage 26 and serves to adjust the latter in the X direction. A compression spring 50, which is arranged between the support arm 22 and the first slide 26 and surrounds the adjusting spindle 46, serves to compensate for a possible play in the thread of the adjusting spindle 46. Such adjusting spindle arrangements are known per se, so that a further description is unnecessary here.

The second carriage 30 likewise consists of a block of material, for example of aluminum or plastic, which engages in the angular space formed by the longitudinal leg 26 'and by the transverse leg 26''of the first carriage 26. A guide rod 54 is inserted on the underside 52 of the second slide 30 and is fastened by means of a screw 56. The guide rod 54 is slidably guided in the guide tube 42 of the first slide 26, so that the second slide 30 can be adjusted in the X direction relative to the first slide 26. The adjustment takes place via an adjustment spindle 58 which is supported on the first slide 26 and which can be rotated via an actuation button 60. A compression spring 62 which is arranged between the first slide 30 and the second slide 26 and surrounds the adjusting spindle 58 effects a possible play compensation for the threaded spindle 58. A more precise description of this threaded spindle arrangement is also unnecessary since such arrangements are known per se .

The function of the device is as follows: after clamping the measuring axis 4 in the bottom bracket housing 2 and after assembling the structural unit formed from the front sprocket arrangement 8 and the pedal crank 10 on the axis end 6 of the measuring axis 4, the first slide 26 is turned by turning the adjustment Spindle 46 is adjusted so that the pointer 28 is exactly aligned with a predetermined ring gear 8 'of the front ring gear arrangement 8. The second slide 30 is then adjusted by rotating the adjusting spindle 58 until the pointer 32 is exactly aligned with a predetermined toothed ring of the rear toothed ring arrangement 34. It is, for example, the middle ring gear of the front or rear ring gear arrangement.

A measuring scale 64 is arranged at the free end of the guide rod 54. This has a division which indicates the different lengths of the bottom bracket shafts of a row of bottom bracket arrangements available for selection. The end edge of the guide tube 42 serves as a pointer device which, due to its position, indicates a certain bottom bracket shaft length.

SPARE PARTS ISA / EP The measuring axis 4 corresponds, for example, to a standard length of the bottom bracket shaft of 122 mm. If the rear sprocket arrangement 34 is offset outwards from the ideal orientation, for example, then the second slide 30 is also offset outwards compared to the first slide 26, as a result of which the measuring scale 64 is positioned opposite the outer edge 66 of the guide tube 42 which serves as a pointer device moves and shows a larger length for the bottom bracket shaft than 122. The fitter now has to mount a bottom bracket shaft, the length of which corresponds to the displayed length. This offsets the offset of the rear sprocket arrangement compared to the front sprocket arrangement.

As can also be seen in FIG. 3, different, interchangeable measuring scales 64, 64 'and 64 ^{fl are} provided which are matched to different lengths of the bottom bracket housing 2.

The different measuring scales 64, 64 ', 64' 'can also be replaced by the fact that several scales are formed on one measuring scale, for example by different colors.

4 shows another embodiment of a scale arrangement 136. In this case, the scale carrier carries a single measuring scale 164. The guide tube 142 is formed at least in its left end region in FIG. 4 as a rotatable sleeve, the end edge 166 of which corresponds three different bottom bracket housing lengths of 68, 70, 73 mm are cut to length differently (cut off). 4a shows the guide tube 142 in a development, wherein the different end edge sections 1'66 ', 166' 'and 166' '' can be seen. By turning the guide tube

SPARE SHEET ISA / EP 142, another end edge section 166 ', 166''or166' ¹¹ , which serves as a pointer device, is brought over the measuring scale 164, so that a display which is matched to the respective bottom bracket housing length is displayed.

4b shows the scale arrangement 136 on an enlarged scale with a cut guide tube 142 or end of the guide tube. One can see the only measuring scale 164 arranged on the scale carrier and the differently deflected end edge sections 166 'and 166' ¹ '. In addition, the measuring scale 164 also includes a millimeter scale 170, which is adjusted to the center of the bottom bracket shell, so that in addition to the required bottom bracket wavelength, a measure of the deviation of the chain line can also be read.

Claims

Patent claims

1. Device for measuring the chain drive of bicycles, training bikes and the like with a bottom bracket housing (2) for receiving the bottom bracket and front sprocket assembly (8) carrying bottom bracket assembly, characterized by

- A measuring axis (4) which can be clamped in the bottom bracket housing (2) and which has an axially projecting part above the bottom bracket housing, in design and dimension essentially corresponding to the corresponding shaft end of the intended bottom bracket arrangement, for receiving at least the front sprocket arrangement (8) ¬ formed axis end (6),

a first carriage (26) which can be adjusted parallel to the direction of the measuring axis relative to the measuring axis (4) and which carries a pointer (28) which can be aligned with the front ring gear arrangement (8),

a second carriage (30) which is adjustable relative to the measuring axis (4) and parallel to the measuring axis direction and which carries a pointer (32) which can be aligned with the rear sprocket arrangement (34),

- And a measuring scale arrangement (36) for displaying the relative position of the two slides (26, 30) to one another.

2. Apparatus according to claim 1, characterized in that one (26) of the carriage is directly adjustable relative to the measuring axis (4), and that the other carriage (30) is adjustably mounted relative to the former carriage.

3. Device according to claim 1 or 2, characterized gekenn¬ characterized in that at the axis end (6) facing away from the axis end of the measuring axis (4) to this transverse arm (22) is attached to which at least the first chute (26) is adjustable.

4. The device according to claim 3, characterized in that the second carriage (30) on the first carriage (26) is adjustably mounted and is additionally guided on the support arm (22).

5. Device according to one of claims 1 to 4, characterized in that on one (30) of the carriage, a measuring scale (64) and on the other carriage (26) a cooperating pointer device (66) is arranged.

6. The device according to claim 5, characterized in that the measuring scale (64) has a division which corresponds to the different length dimensions of the bottom bracket shafts egg stock on different bottom bracket arrangements.

7. Apparatus according to claim 5 or 6, characterized gekenn¬ characterized in that several, matched to different bottom bracket housing lengths measuring scales (64, 64 ', 64' ') are seen.

8. The device according to claim 7, characterized in that a plurality of interchangeable measuring scales (64, 64 ', 64' ') are provided.

9. Device according to one of claims 3 to 8, characterized in - That the first carriage (26) carries a guide tube (42) aligned in the adjustment direction X, which is displaceably guided in a guide bore (44) formed in the support arm (22),

- that the second slide (30) carries a guide rod (54) aligned in the adjustment direction X, which is slidably guided in the guide tube (42) of the first slide (26),

- That a measuring scale arranged at the end of the guide rod (54) protrudes beyond the end of the guide tube (42), the end edge (66) of the guide tube

(54) serves as a pointer device which interacts with the measuring scale (64).

10. The device according to claim 9, characterized in that a first, on the support arm supporting Verstell¬ spindle (46) for adjusting the first carriage (26) and a second, on the first carriage (26) supporting adjusting spindle (58) are provided for adjusting the second slide (30).

11. The device according to one of claims 4 to 10, characterized in that on the second carriage (30) a pointer (32) is arranged, which is adjustable in the chain drive plane in its length direction and / or in its angle setting.

12. The device according to one of claims 1 to 11, characterized in that the projecting axis end

(6) the end facing away from the measuring axis (4) carries a fixed flange (16) which bears against the associated end face of the bottom bracket housing (2), and that the measuring axis (4) enters in the region of the projecting axis end (6) Has an external thread onto which a screw nut (18) bearing against the other end of the bottom bracket housing (2) can be screwed.

13. Device according to one of claims 9 to 12, characterized in that on the guide rod (54) offset in the circumferential direction a plurality of measuring scales (64) are arranged and that the guide rod (54) is rotatable about its longitudinal axis.

14. Device according to one of claims 9 to 12, characterized in that the guide tube (142) at its free end (166) has a plurality of axially offset end edge sections (166 ', 166' ', 166' '') and that at least the end section of the guide tube (142) can be rotated about the guide tube axis.

15. Device according to one of claims 3 to 12, characterized in that the measuring axis (4) in the support arm (22) is rotatably mounted and is equipped with an actuating button (24) for rotating.