DEVICE FOR TRUEING OF THE RIM OF A SPOKE WHEEL

Abstract: What is disclosed is a device for trueing the rim (4) of a spoke wheel (2) provided with spokes, which device comprises a spoke tensioning mechanism, which is mounted on a setting mechanism which comprises four pivots (A, B, C, D). When the spoke tensioning mechanism is being moved, the setting mechanism does the moving and at the same time maintains the correct square angle relative to the spoke nipple, without measuring or sensor means being required for that purpose.

Description: DEVICE FOR TRUEING OF THE RIM OF A SPOKE WHEEL The present invention relates to a device for trueing the rim of a spoke wheel, which device comprises a spoke tensioning mechanism. A device of this kind is known from EP-A-0 476 749. The known device for trueing the rim of a spoke wheel is provided with a spoke tensioning mechanism fitted with rotary nipple wrenches, which spoke tensioning mechanism comprises means for setting the nipple wrench at right angles to a spoke. Said means comprise a measuring element with a feeler and two sensors, by means of which deviations in the squareness between the nipple wrench and the spoke in question can be established. Sensor- controlled steering means steer a nipple wrench setting element until the nipple wrench extends at right angles to the spoke. One drawback of this prior art device is its complex construction comprising measuring means and sensor means. The object of the present invention is to provide an efficient, high-quality device of simpler construction, which is suitable for providing a degree of squareness between a spoke tensioning mechanism and a spoke which is sufficient in practice. In order to accomplish that objective, the device according to the invention is characterized in that the device comprises a setting mechanism which is pivoted in at least four points, on which mechanism the spoke tensioning mechanism is mounted. The advantage of the construction of the device according to the invention is that the setting mechanism comprising four pivots, on which the spoke tensioning mechanism is mounted, has optimum characteristics as regards vertical adjustment and angle maintenance. These characteristics appear to make the setting mechanism pre-eminently suitable for setting the spoke tensioning mechanism at right angles to the nipples on the spokes and maintaining that position while the nipples are being turned, without complicating measuring means and sensor means being required. The spoke tensioning mechanism is furthermore adjustable for height, whilst the optimum square angle between the spoke tensioning mechanism and the nipple is maintained during said vertical adjustment so as to achieve a correct setting and an optimization of the grip on the various nipples. Another advantage of the device according to the invention is that, due to the absence of the aforesaid complicating means, it has become not only simpler as regards its construction, but also less vulnerable and less costly while requiring less maintenance, without this having an adverse effect on the good functionality thereof. Further advantageous embodiments of the device according to the invention are defined in the subclaims. The invention and its further advantages will now be explained in more detail with reference to the appended drawings, in which corresponding parts are indicated by the same numerals in the various figures. In the drawings: Figure 1 shows a part of a possible embodiment of the device according to the invention which is relevant for the present invention; Figure 2 is a schematic diagram of the invention; and Figure 3 shows a detail of a possible sensor arrangement for use in the device of Figure 1. Figure 1 shows a part of a device 1, by means of which it is possible to tension spokes S and S' in a spoke wheel 2 by means of a spoke tensioning mechanism (schematically shown) , which includes inter alia a nipple wrench 3, in such a manner that both axial and radial deviations in the shape of rim 4 of spoke wheel 2 are corrected. The spokes S and S', which are biassed between a flange 5 near axle 6 and rim 4, are tensioned or relaxed by means of the rotary nipple wrench 3 during the trueing of spoke wheel 2. Spoke wheel 2 is moved in one direction during said trueing, or alternately in one direction and the other, the latter being preferred in connection with a saving of the time needed for trueing that can be achieved in that case. In the embodiment which is shown in Figure 1, the schematic diagram of which is furthermore shown in Figure 2 for the sake of clarity, the nipple wrench 3 can be rotated by means of a rotary motor 7. Nipple wrench 3 can be moved by means of an element 8, which is fixedly mounted on a beam 9 which is capable of pivoting movement about two pivots A and B. Connected to pivots A and B are two further beams 10 and 11, which are also pivot-mounted on pivots C and D, which pivots are mounted in a block beam 12. Beams 9 - 11 and block beam 12 with respective pivots A, B, C and D together form a setting mechanism for the nipple wrench 3. Beam 9 can be moved by means of a shifting element 13 mounted between beam 10 and block beam 12, which may for example be a linear motor, and which functions to set the desired angle between spoke S, S' and nipple wrench 3, which is usually about 90 degrees, independently of the type of spoke wheel 2. Block beam 12 can be moved as a whole by means of vertical setting element 14 for the purpose of adjusting the height, which depends on the location and the type of rim 4 of spoke wheel 2. One movable beam 9 is shorter than the other part on block beam 12, which extends between pivots C and D. In the illustrated embodiment, the shorter beam 9 of the setting mechanism, which at some point is trapezoidal, is positioned near spoke wheel 2. Device 1 possesses a setting element 15, by means of which the nipple wrench can be moved along spoke S, S' to the nipple in question. The setting mechanism comprising the four pivots thereby provides optimum vertical adjustment and angle- maintaining characteristics, so that the nipple wrench 3 will properly fit at the correct square angle on the nipples in question. Figure 1 furthermore shows that setting mechanisms are disposed to the left and to the right of the spoke wheel 2 for the purpose of correctly tightening nipples which are present on groups of spokes S and S' extending at different angles relative to rim 4. A rim driving unit, usually comprising at least one stepping motor 16, causes the spoke wheel 2 to rotate about the axle 6 which is to be clamped down. It stands to reason that each of the elements 8 and 13 - 15 is driven at successive, programmed times to a degree adapted to the type of spoke wheel, the rim and the number of spokes by programmable processor means (not shown) . The setting of the aforesaid angle of about 90° between spokes S, S' and the nipple wrench 3 takes place on the basis of preceding measurements carried out by measuring means (not shown) , wherein the following values are measured or determined: the diameter of the spoke wheel 2, the spacing between the two flanges 5 on axle 6, the type of wheel, that is, a rear wheel or a wheel with multiple sprockets, and the rim height. The rim height may for example be determined by placing sensor-receiver means 17 and 18 as shown in the detail of Figure 3 on either side of the spoke wheel 2, which will continue to transmit a shift command to setting element 14 until one of the means 17 and 18, means 17 in the illustrated embodiment, switches as a result of the absence of incident light, whereby said shift is measured by a pulse counter, for example, from which the rim height can be derived. Means 17, 18 may for example also include one light transmitter-receiver, rather than two, of course.

Claims: CLAIMS 1. A device for trueing the rim of a spoke wheel, which device comprises a spoke tensioning mechanism, characterized in that the device comprises a setting mechanism which is pivoted in at least four points, on which mechanism the spoke tensioning mechanism is mounted. 2. A device according to claim 1, characterized in that the device includes a shifting element connected to the setting mechanism for moving said setting mechanism. 3. A device according to claim 1 or 2, characterized in that said setting mechanism includes two beams positioned opposite each other, wherein one beam is capable of movement relative to the other beam. 4. A device according to claim 3, characterized in that one beam is of shorter length than the other beam. 5. A device according to claim 4, characterized in that the spoke tensioning mechanism is mounted on said shorter beam. 6. A device according to claim 4 or 5, characterized in that said shorter beam is positioned closer to the spoke wheel than the other beam. 7. A device according to any one of the claims 1 - 6, characterized in that said setting mechanism includes two further beams positioned opposite each other, and in that said shifting element is coupled to one of said two further beams. 8. A device according to any one of the claims 1 - 7, characterized in that the device comprises two setting mechanisms. 9. A device according to claim 8, characterized in that the two setting mechanisms are disposed on either side of the spoke wheel . 10. A device according to any one of the claims 1 - 9, characterized in that the spoke tensioning mechanism includes a nipple wrench for turning a nipple present on the end of the spoke at the location of the rim.

Inventors: BEST BOB, BOSNJAK MLADDEN, BEST, BOB, BOSNJAK, MLADDEN
Applicants: BEST BOB, BEST MACHINE DEV V O F, BOSNJAK MLADDEN, BEST MACHINE DEVELOPMENT V.O.F., BEST, BOB, BOSNJAK, MLADDEN
Application year: 1999
Main classification: B60B31
IPC codes: B60B31