Patent Application
20050034279
The invention relates to a textile machine, especially a spinning preparation machine with a drafting device. The drafting device has several drive disks for driving machine elements, especially drafting device rollers, and has at least one endless belt surrounding at least two drive disks.
Textile machines that employ drafting devices are widely known. Three roller pairs are provided in drafting frame RSB-D 35 of the Rieter company that have a circumferential speed that increases from the entrance of the drafting device to the exit of the drafting device. The particular lower roller of the drafting device rollers is driven by flat belts for producing a drive that is as slippage-free as possible to provide for an orderly drafting of the slivers [slubbing]. The upper rollers are pressed against the lower rollers, thus clamping the yarn [fiber] material running through between them.
It turned out that flat belts have many advantages over the earlier toothed-type belts still frequently used at times but that an undesired elongation slippage can result due to the relatively high elasticity of the flat belt. This springiness of the flat belt occurs in particular during a dynamic change of speed so that errors result in the transfer behavior. In addition, a re-adjustment must be performed in the case of an irreversible elongation and the sliding slippage produced as a consequence thereof. In contrast thereto, toothed-type belts, that, in addition, are relatively easy to manipulate, have less of a tendency to slip but have the disadvantage that that they run unevenly when contaminated. In addition, toothed-type belts exhibit the so-called polygon effect in which knocks occur due to the teeth folding into the gaps between the teeth. One other disadvantage is the fact that no continuous translation change is possible with toothed-type belts.
It is therefore a principal purpose of the present invention to create an improved drive for drive disks in a textile machine. Additional advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
This principal purpose is solved for a textile machine by a belt comprising at least two longitudinal ribs on one side that are received in corresponding longitudinal grooves of at least one drive disk that are on the circumferential side and run in the circumferential direction.
Several advantages result from using a belt longitudinally profiled with ribs and grooves in accordance with the invention. One advantage is the fact that the belt is guided more precisely in the longitudinal direction in comparison to a flat belt due to its rib-and-groove structure. A centered belt course is always guaranteed by means of the at least two longitudinal ribs. Therefore, the use of such a belt is also possible in the case of not absolutely parallel shafts [axes]. In addition, no periodic errors occur in the case of contamination in comparison to a toothed-type belt with its transverse grooves. Also, no polygon effect disturbs the even running, as is the case for toothed-type belts. Therefore, greater dynamics with better transfer properties can also be achieved with the belts exhibiting the longitudinal rib-and-groove structure.
On the whole, a very even, almost oscillation-free running can be achieved in contrast to toothed-type belts. Moreover, the stiffness of such a belt and its modulus of elasticity are greater than in a flat belt, so that a more precise transfer behavior results, especially in the case of dynamic changes of speed. Thus, a more favorable dynamic behavior can be achieved at such changes of speed with the belt in accordance with the invention.
Furthermore, a continuous translation change is possible when using the cited belt in accordance with the invention, which is a serious disadvantage with toothed-type belts in particular.
Also, greater translation conditions [ratios] and greater belt speeds can be achieved with the drive of the invention compared to the previously used belts, e.g., belt speeds of 60 m/s. Since the contact surface is greater due to the longitudinal profiling compared to a flat belt with the same belt width, on the whole greater performances [power] can be transferred. In this manner, very high speeds of the drive disks and therewith in particular of the drafting device rollers can be achieved so that sliver delivery speeds of distinctly more than 1000 m/min with a high degree of precision of the drafted sliver are possible.
Another advantage over traditional toothed-type belts is the fact that the use of belts with rib-and-groove structure in accordance with the invention makes possible crossed or bent belt drives in which the axes of two looped drive disks do not run parallel to or at 90° to one another. This significantly increases the structural play during the construction of the machine.
Further, the circumferentially running grooves of the drive disks can be produced relatively simply by turning using a shaping chisel with any desired diameter. Turning has the additional advantage that no graduation with a fixed number of teeth (as in the case of a toothed-type belt) is necessary. The forming of running grooves of the drive disks is simpler and easier as compared to creating recesses in the drive disk use with tooth-type belt, whereby, the recesses of the drive disks for toothed-type belts must be laboriously milled or tapped.
The ribbed belt comprises in an especially preferred manner more than two longitudinal ribs running parallel to each other. The plurality of ribs with longitudinal grooves arranged between them assure on the one hand a uniform distribution of force over the entire belt width and on the other hand guarantee an especially good frictional connection.
The at least two longitudinal ribs can be designed in a wedge shape [V-shape] in an advantageous embodiment. This results in a wedge-rib [V-ribbed] belt known from other areas of application that has an extremely high flexibility so that great translation ratios can be achieved even with very small drive disks (e.g., 1:40). Also, great counterflections can be achieved with such a belt so that a versatile use with a low space requirement is possible.
The side of the belt opposite the ribs and grooves can be designed in various manners. In one variant, this opposite side is designed to be flat, so that during the deflection of the belt this flat side runs on a drive disk. This drive disk can have either the cited rib-and-groove profiling in the longitudinal direction or a smooth surface or even a toothed profile.
Alternatively, for example, the belt may also have a profile on its side facing away from the longitudinal ribs, which has at least two longitudinal ribs, or the belt may have a profile with transverse ribs, that is, a tooth profile. In the first-cited instance of a double profiling with longitudinal ribs, the front and the back side of the belt can be used in accordance with the invention, which is especially advantageous given differences in the direction of rotation of two shafts.
A cleaning effect of the belt can be achieved in the case of a profiling on only one side as well as one on both sides by deflection on both sides, a suitable looping angle and by a differing flexion, so that the dirt can fall out of the grooves and does not settle on the surfaces of the drive disks.
Cleaning devices, e.g., permanently arranged brushing-off devices or nozzles with a blowing pulse can be used to clean the belt grooves and/or the drive disks.
Several driven disks can be simultaneously driven with particular preference by a drive disk through the means of the rib belt or wedge-rib belt. This possibility results from the fact that greater performances can be transferred in comparison to flat belts. Thus, one drive shaft and several driven shafts can be arranged on one belt line. The intermediate shafts required in the state of the art can be eliminated. The number of belts and, in particular, the number of shafts and supports can thus be reduced in comparison to the known, comparable textile machines, which can lower expenses. Also, on the whole smaller masses to be driven result, so that the massive inertias are also smaller and therefore greater machine dynamics can be achieved. In addition, only the one belt needs to be slackened if several change gears are to be replaced on this belt line, e.g., for adjusting a different sliver fineness of the drafted material or for adapting the machine to different textile materials. Previously, in order to replace any change gear the associated belt had to be slackened.
In another aspect of the invention, the textile machine includes a device by means of which the at least one belt can be adjusted independently of its length and the diameter of the at least one looped drive disk to a belt tension that is substantially the same in all instances. In the traditional toothed-type belt drives, the belt tension is adjusted by the operator according to his own judgment or with the aid of an appropriate measuring device to a value that is fixed at first. In the case of known flat belts, their theoretical tension can be fixed with the aid of a clamping screw arranged on a tensioning lever. A tensioning or deflection roller for the flat belt is arranged on the spring-loaded tensioning lever. Thus, even the tensioning roller is held in its place by fixing the clamping screw. If the flat belt or the previously cited toothed-type belt expands in a non-elastic manner, the belt tension is reduced; so that it must be readjusted by the user. A different spring may have to be used during a replacement of the drive disk by a drive disk with a different circumference.
In contrast thereto, in the cited aspect of the invention, the belt tension adjusts itself to a value that is substantially the same in all instances without the user actively adjusting the belt tension by using force or the like, so the expense for maintenance and replacement is reduced. The belt tension can adjust itself in this instance to the predetermined value independently of the size of the drive disk or the length of the belt used. Measurement of the belt tension and an unclear reliance on values gained from experience are no longer necessary.
To this end, the device comprises in an especially preferably manner at least one movably mounted tensioning roller or deflection roller for belt tensioning that is force-loaded and thus correspondingly tensions the belt to the predetermined force without the user having to intervene. To this end, the tensioning roller is mounted, e.g., in a linearly guided carriage on which the force is to be applied by the device. In this manner, a predetermined belt tension can be realized even with different change gear diameters or when adjusting different roller settings. The belt tension adjusts itself in the case of different diameters of change drive disks or the case of belts with different lengths by shifting the tensioning roller to a constant value when the looping angle (engagement angle) of the belt around the tensioning roller is approximately 180° according to a preferred embodiment. If this angle number is deviated from, the belt tension for change gears with a different diameter assumes different values. However, these different values can be in the tolerated range, depending on the area of application. Thus, it is possible that looping angle is in a range between approximately 170° and 190° or also in a range between 160° and 200°.
The cited tensioning roller is preferably loaded directly or indirectly with a spring force that is preferably applied by a gas spring. A gas spring has the particular advantage that the force-path characteristic curve runs approximately horizontally, so that, in the case of the cited looping angle of approximately 180°, a constant belt tension can be adjusted even given different deflections of the tensioning roller due to, e.g., belt expansion or after a replacement of drive disks with different diameters.
In addition, if the gas spring is advantageously provided with a damping, oscillations of the at least one belt during the operation of the machine can be largely prevented.
In an alternative advantageous embodiment, the tensioning roller can be fixed in its position by a fixing device in order to avoid oscillations during operation here too. The fixing device, e.g., a clamping screw, can act on the above-cited carriage to this end in accordance with the embodiment, thereby fixing it in its position. Loosening the fixing device brings the belt to the predetermined tension on account of the loading of force that is then active, so that subsequently only the fixing device must be reactivated. The operator, therefore, does not have to re-tension the belt himself. During a replacement of one drive disk by a drive disk with a different diameter, the looping of the tensioning roller with a looping angle of approximately 180° thus makes possible a rapid and automatic belt tensioning up to the loosening and re-fixing of the fixing device.
Alternatively, the belt tension can also be constantly tensioned continuously, that is, without a fixing in place of the tensioning roller, during the operation of the machine. An example of such a constant and continuous tensioning is the above-cited gas spring with damping. A constant compensation of the longitudinal tolerance of the belt is achieved therewith. Also, the service life of the belt is increased by the continuous adjusting of the optimum tension. Thus, in this embodiment, no fixing device is necessary.
Advantageous further developments of the invention are described further in the following description.
The invention is explained in detail in the following with reference made to the figures.
Reference will now be made in detail to the presently preferred embodiments of the invention, one or more examples of which are shown in the figures. Each example is provided to explain the invention, and not as a limitation of the invention. In fact, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a further embodiment. It is intended that the present invention cover such modifications and variations.
A transmission plan of a drafting frame with drafting device 2 is shown in
The transmission plan of
The following driven disk 8 drives deflection drive 9 and the correspondingly deflected belt 10 drives the two disks, running in opposite directions, of a known groove-sensing roller pair with the aid of drive disk 12 and belt 11. With the aid of groove sensing roller pair, the fluctuations in the sliver cross section are determined for being leveled out in drafting device 2.
The last driven disk 21 driven by belt 7 is connected via shaft 22 to two driven disks 23, 26. The device disk 23 drives lower entrance roller 30 with the aid of belt 24 and another driven disk 25. The driven disk 26 drives lower middle roller 31 with the aid of another belt 27 and another driven disk 29. The particular upper rollers (not shown) are cause to rotate by being pressed against lower rollers 30, 31.
The second motor 40 is connected via drive shaft 41 to two drive disks 42, 51. Driven disk 42 causes two calander rollers to rotate in opposite directions via belt 43 on the one hand with driven disk 44 for driving lower exit roller 32 and on the other hand with driven disk 45 and with the aid of a known transmission [changeover] 46 (driven here with a toothed belt). The sliver (shown in dotted lines) given off from the exit roller pair with running direction A is transported by calander rollers 48 into sliver conduit 49 arranged in rotary plate 50 and deposited from the latter into rotating can 59. Calander rollers 48 as well as the can stock together with can 59 are shown tilted in the transmission plan of
Finally, rotary plate 50 is driven via the other drive disk 51 connected to shaft 41. To this end, belt 52 is looped around drive disk 51, which belt drives driven shaft 53 and driven disk 54 coupled to it. Driven disk 54 is permanently connected to driven disk 55 that drives the rotary plate via belt 56. Can plate 58 is driven via driven disk 54 by means of drive 57 in order to selectively cause can 59 to rotate during the filling process.
A few or all belts 7, 18, 24, 27, 43, 52 in accordance with
Belt 280 in accordance with
In order to avoid any oscillations during operation, carriage 94 (or also tensioning lever 96) can be clamped fast by clamping screw 97 or some other fixing device so that tensioning roller 95 is power-loaded except to monitor the tensioning force or for a subsequent tensioning by gas spring 99. To this end, clamping screw 97 is loosened so that the belt tension can automatically readjust itself, and subsequently clamping screw 97 is retightened.
If one of driven disks 75a, 75b is replaced by the other one, at first the belt tension is reduced by pivoting the tensioning lever 96. If clamping screw 97 is used, it is also loosened. After having pivoted the tensioning lever 96 back, the same belt tension is then automatically adjusted for the new driven disk 75a or 75b by virtue of the power-loading by gas spring 99 as for the replaced drive disk 75b and 75a. The clamping screw can subsequently be retightened. Any other manual intervention by the user is unnecessary.
In another, even simpler embodiment clamping screw 97 is not present. Instead, gas spring 99 is designed to be damped in order to avoid oscillations of belt 80 during operation. The construction is otherwise the same as the one shown in
Looping angle α of 180° does not have to be absolutely maintained if a certain error can be accepted without this resulting in a noticeable or significant loss of quality in the resulting sliver. The belt tension is different at an angle α deviating from 180° when using driven disk 75a than that when using driven disk 75b. Looping angle α can be, e.g., between approximately 160° and 200°. For example, in some practical examples, a looping angle of 170° still shows good results.
The present invention is not limited to the exemplary embodiments shown and described. Modifications within the scope of the patent claims are readily possible. Thus, even other longitudinal rib profiles than the wedge ribs shown can be used. It will be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 103 30 950.0 | Jul 2003 | DE | national |
