Method and apparatus for manufacturing spokes

Abstract

A method and a device are provided for manufacturing spokes from a wire material, in particular for at least partially muscle-powered two-wheeled vehicles. The spokes include a spoke shaft having at least two shaft sections. The shaft sections differ in at least one cross-section. For shaping the cross-sections, the wire material is reshaped at least in sections by means of a shaping tool. The relative position of the wire material relative to the shaping tool is varied in the axial direction during reshaping. For shaping the cross-sections in the two shaft sections the relative position of the wire material relative to the shaping tool is varied by way of different positioning movements.

Claims

1. A method of manufacturing spokes from a wire material by a reshaping device for at least partially muscle-powered two-wheeled vehicles, the method comprising: providing spokes made with the wire material, each of the spokes comprising at least one spoke shaft having at least two shaft sections, wherein the at least two shaft sections differ in at least one cross-section; shaping the cross-sections of the at least two shaft sections by forging using a shaping tool of the reshaping device, wherein the shaping tool reduces a diameter of the wire material by a plurality of blows while varying the relative position of the wire material relative to the shaping tool in an axial direction by at least one feeding device of the reshaping device, wherein movement of the wire material relative to the shaping tool during shaping of the cross-sections of the at least two shaft sections is at different speeds; and adjusting a reduction depth of the shaping tool to adjust the diameter of the wire material using at least one adjustment device of the reshaping device.

2. The method according to claim 1, wherein the movements of the wire material relative to the shaping tool during shaping of the cross-sections of the at least two shaft sections differ in at least one of maximum speeds and minimum speeds.

3. The method according to claim 1, wherein movement of the wire material relative to the shaping tool during shaping of the cross-sections of the at least two shaft sections is at least one of an intermittent speed and at a continuous speed.

4. The method according to claim 1, wherein at least one movement of the wire material relative to the shaping tool during shaping of the cross-sections of the at least two shaft sections is a continuous movement.

5. The method according to claim 1, wherein at least one movement of the wire material relative to the shaping tool during shaping of the cross-sections of the at least two shaft sections is an incremental movement.

6. The method according to claim 1, wherein the shaping tool is rotated about a longitudinal axis of the wire material and wherein movement of the wire material relative to the shaping tool during shaping of the cross-sections of the at least two shaft sections is interrupted for a specified time interval and the time interval of the interrupted movement corresponds at least to the duration of one rotation of the shaping tool about the longitudinal axis of the wire material.

7. The method according to claim 1, wherein the shaping of the at least two shaft sections having identical cross-sections is performed by identical movements of the wire material relative to the shaping tool.

8. The method according to claim 1, wherein the shaping of cylindrical shaft sections is performed by movements of the wire material relative to the shaping tool having identical effective speeds.

9. The method according to claim 1, wherein the shaping of a shaft section having variable cross-sections is performed by movements of the wire material relative to the shaping tool that is at an effective speed that is lower than when shaping a shaft section having a consistent cross-section along a designated length.

10. The method according to claim 1, wherein the shaping of a shaft section having variable diameters, which serves as a taper between two cylindrical shaft sections each having a different diameter, the movement of the wire material relative to the shaping tool is performed at an effective speed that is lower than in the immediately adjacent shaft sections.

11. The method according to claim 10, wherein the shaft section serving as a taper is configured cone-shaped or conical.

12. The method according to claim 11, wherein at least one of the effective speed and the maximum speed of the movement of the wire material relative to the shaping tool during shaping is reduced prior to reaching the taper and is increased after the end of the taper.

13. The method according to claim 11, wherein the movement of the wire material relative to the shaping tool is performed in increments during the taper.

14. The method according to claim 1, wherein the effective speed of one of the movements takes place in dependence on at least one of a rotational speed of the shaping tool about the longitudinal axis of the wire material and a hammering rate of the shaping tool.

15. The method according to claim 1, wherein the effective speed of one of the movements is adjusted in dependence on the diameter of the cross-section of the shaft section.

16. The method according to claim 1, wherein the shaping tool comprises at least two opposed tool units, and wherein the tool units act on the wire material in synchrony by hammering.

17. The method according to claim 1, wherein the forging of the wire material by the shaping tool continues during execution of the different axial movements of the wire material relative to the shaping tool.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and features of the present invention can be taken from the description of the exemplary embodiments which will be discussed below with reference to the enclosed figures.

(2) The figures show in:

(3) FIG. 1 a schematic view of a bicycle;

(4) FIG. 2 a schematic view of a spoke;

(5) FIG. 3 a simplistic illustration of a device according to the invention;

(6) FIG. 4 a simplistic drawing of various positioning movement paths; and

(7) FIG. 5 a simplistic drawing of further positioning movements.

DETAILED DESCRIPTION

(8) FIG. 1 shows a schematic illustration of a two-wheeled vehicle 200 configured as a bicycle. The bicycle comprises two wheels 201, a front wheel and a rear wheel. Furthermore, a frame 203, a fork 204, a handlebar 206, and a saddle 207 are provided. The drive is provided by pedals and in this case, a derailleur. The front wheel and the rear wheel are each attached to dropouts at the fork 204 respectively the frame 203. The front wheel and the rear wheel 101, 102 each comprise a rim 210 and spokes 100 manufactured by means of the device according to the invention and connected with a hub 208. Due to the image scale the spokes 1 are shown schematically only and will be illustrated in more detail with reference to FIG. 2.

(9) FIG. 2 illustrates a schematic longitudinal view of a spoke 100 manufactured by way of the method according to the invention. The figure is not true to scale to better illustrate the principle. Two exemplary cross-sections 103 of the spoke are illustrated hatched. The cross-sections 103 differ in their diameters 33. The transitions between the regions of different diameters 33 are provided by the tapers 104. The tapers 104 differ in their lengths and in their gradients. An arrow indicates the longitudinal axis 23 of the spoke.

(10) The spoke 100 has been manufactured by reshaping wire material 3. The wire material used is a special spoke wire which has a tensile strength of e.g. 1200 N/mm.sup.2 and more. The spoke wire was reduced by hammering on the respective cross-sections 103 respectively 33.

(11) The spoke 100 has a spoke head 105 at one of its ends and at the other of its ends, an external thread 106 which serves to screw it to a spoke nipple, which is not shown. The spoke shaft 101 extends between the two ends. The first end 105 is for attachment to the hub 208. The spoke 200 extends outwardly from the hub 208 to the second end 106 where the external thread is then attached to the rim 210 by means of a spoke nipple.

(12) This spoke 100 is exemplarily configured as a double-butted spoke. Other spoke shapes are also conceivable such as single-butted spokes or else flat spokes. This spoke shaft 101 has undergone controlled reshaping in various shaft sections 111, 121, 131, 141, 151. The two shaft sections 111, 151 at the ends 105, 106 are configured cylindrical, having a cross-section 103 with a diameter of 2.0 mm. The shaft section 131 lying between is likewise cylindrical and has a cross-section 103 with a diameter 33 of 1.5 mm.

(13) Such reduction of the spoke shaft 101 allows to noticeably reduce the weight while concurrently maintaining and even increasing the required stability. The tapers 104 are shaped so as to counteract an unfavorable notch effect and to allow a particularly stable transition. The shaft section 121 closer to the head 105 has a shorter taper 104 than does the shaft section 141 lying closer to the other end 106. This configuration takes account of the forces occurring in the wheel 201 which act on the spoke 100.

(14) FIG. 3 exemplarily shows the device 1 according to the invention for manufacturing spokes 100. The device 1 may be operated according to the method according to the invention. The device 1 comprises a reshaping device 2 for reshaping wire material 3. The wire material 3 is fed through the reshaping device 2 by means of a feeding device 8 which is presently configured as an advancing device.

(15) The reshaping device 2 comprises a shaping tool 4 having two or four pairs of opposed tool units 14, of which only one tool unit 14 is shown for better clarity. An actuating device is provided for actuating the shaping tool 4. The actuating device 5 is configured as a hammering roller device 15 which comprises a plurality of stationary hammering roller units 25 and displaceable hammering roller units 35.

(16) An adjustment device 6 is provided for setting a reduction rate. The adjustment device 6 comprises a wedge device 16 disposed between the hammering roller unit 35 and the tool unit 14. Axial displacement of the wedge device 16 adjusts the distance between the hammering roller unit 35 and the tool unit 14 to allow adapting the reduction depth accordingly.

(17) FIG. 4 shows an exemplary process pattern of the method according to the invention. The relative position 43 of the wire material 3 was plotted in relation to the shaping tool 4 versus the time 702. This results in a characteristic path including each of the different positioning movements 7 during reshaping of the wire material 73. The different positioning movements 7 comprise a first positioning movement 712, followed by a second positioning movement 722 and a third positioning movement 732. The drawn path reflects the maximum speeds 27 of the positioning movements 7. Each of the positioning movements 7 is performed as a continuous movement 37.

(18) The respective relative positions 43 correspond to specific positions of the shaping tool 4 during the processing along the spoke shaft 101. The presently shown path exemplarily shows reshaping of a spoke shaft 101 having a total of three different shaft sections 111, 121, 131. The wire material 3 is first taken to a relative position 43 where reshaping of the first shaft section 111 begins. This shaft section is for example cylindrical and is processed by way of a suitable, rapid speed 27. The same applies to the third shaft section 131.

(19) The second shaft section 121 is exemplarily configured as a taper 104 between the first shaft section 111 and the third shaft section 131. Since the taper 104 exemplarily undergoes conical or cone-shaped reshaping, the speed 27 is accordingly reduced for the time 702 of processing. This allows particular precise shaping of the taper 104 showing very narrow tolerances.

(20) FIG. 5 shows another outline of an exemplary path of positioning movements 7. Similarly, to the description in FIG. 4, a spoke 100 having a spoke shaft 101 consisting of a total of three shaft sections 111, 121, 131, is reshaped. The first positioning movement 712 is performed at a lower speed 27 than is the third positioning movement 732.

(21) This controlling of the wire feed is useful for example in manufacturing a double-butted spoke whose shaft sections 111, 131 show different cross-sections respectively different diameters 33 at their two ends 105, 106. For example, if the diameter 33 of the spoke shaft 101 is smaller, the processing speed 27 may be lower since the wire material 3 is reduced more in this position. Or else it is possible to provide positioning at the same or similar speeds 27 even given different degrees of reduction of the spoke shaft 101.

(22) For shaping the second shaft section 121 the presently shown process flow comprises a positioning movement 722 that is configured as an incremental movement 47. Such incremental movement 47 provides for temporarily stopping the positioning movement 7 and temporarily bringing it up to a specific maximum speed 27. The stop of the positioning movement 7 lasts for a specific time interval 57. This time interval 57 corresponds for example to the duration of one rotation or part of one rotation of the shaping tool 4 about the wire material 3. Or else it is possible to match the time interval 57 to the duration of adjusting the shaping tool 4. The maximum speed 27 between stops can be chosen accordingly higher. Thus there results an overall effective speed 17 allowing correspondingly fast reshaping and thus an economic manufacturing throughput. Varying the speed may be done continuously over a spoke section or part of a spoke section.

(23) It is in particular possible to choose a positioning movement 7 respectively speed of the relative motion between the spoke shaft and the reshaping device e.g. in the spoke sections 121 and 141 in FIG. 2 that differs from that in the spoke sections 111 or 131. In spoke sections where the thickness varies, a lower speed can in particular be chosen. Then, care is taken for the spoke shape in the respective spoke sections 121 and 141 to precisely adapt to the shape of the tool so that narrow tolerances can be achieved since the shape of the spoke section corresponds to the shape of the tool.

(24) The spoke sections 111 and 151 having maximum diameters may be provided for no processing at all.

(25) The presently shown method allows manufacturing spokes 100 having particularly narrow tolerances in particular in the region of the tapers 104. A tolerance of less than +/0.5 mm can be realized for example in the region of the tapers 104. The tolerance of the methods known thus far is e.g. up to 3 mm and more. The method according to the invention thus achieves a considerable increase of dimensional consistency. Moreover, these precise transitions also offer an improved optical appearance and improved aerodynamic properties.

(26) The increased dimensional consistency achieved with the method according to the invention is an advantage in particular for flat spokes respectively bladed spokes. Flat spokes having a wide tolerance range tend to comprise cylindrical regions or too large transverse dimensions so that problems may arise when inserting spokes through the rim hole. On the whole the method according to the invention offers considerable advantages in manufacturing spokes which can be employed in particular in building high-end wheels.

(27) While a particular embodiment of the present method and device has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.

(28) TABLE-US-00001 List of reference numerals: 1 apparatus 2 reshaping device 3 wire material 4 shaping tool 5 actuating device 6 adjustment device 7 positioning movement 8 feeding device 14 tool unit 15 hammering roller device 16 wedge device 17 speed 23 longitudinal axis 25 hammering roller unit 27 speed 33 diameter 35 hammering roller unit 37 movement 43 relative position 47 movement 54 head section 57 time interval 100 spoke 101 spoke shaft 103 cross section 104 taper 105 spoke head 106 external thread 111 shaft section 121 shaft section 131 shaft section 141 shaft section 151 shaft section 200 two-wheeled vehicle, bicycle 201 wheel 203 frame 204 fork 206 handlebar 207 saddle 208 hub 210 rim 702 time 712 positioning movement 722 positioning movement 732 positioning movement