Patent Application
20060021197
The present invention relates to a revolving plate for a sliver depositing device of a sliver-producing or sliver-processing spinning preparation machine in accordance with the generic part of Claim 1 as well as to a method for depositing a sliver that is supplied in a running manner into a container in accordance with the generic part of Claim 18.
DE 41 31 134 teaches a revolving plate with a spatially curved sliver passage consisting of a tubular section with two circular arcs that merge directly into one another. This has the disadvantage that particles that are occasionally loosened out of the sliver settle on the inner wall of the sliver passage.
These particle accumulations have the tendency to increase to a certain size during the running operation of the depositing of sliver in order to then come loose from the inner wall as closed particle compounds. This coming loose frequently occurs when the container receiving the sliver is replaced. As a rule, the particle compounds (so-called mice) fall into the container and therefore contaminate the deposited sliver. This can result in problems in the further processing of the sliver.
Particle accumulations on the inner wall of the sliver passage can additionally cause damage to the sliver to be deposited, especially at high and extremely high depositing speeds. The particle accumulations can result, e.g., in a wrong draft in the sliver or in a deterioration of the degree of parallelization of the slivers.
It is furthermore disadvantageous that a high longitudinal tension is required in the sliver during operation in the case of the revolving plate shown in order to draw the sliver through the sliver passage. This creates an undesired spinning start draft that impairs the quality of the deposited sliver.
The present invention has the problem of creating a revolving plate and a method that overcome the cited disadvantages and ensure a reliable and protective depositing of a high-quality sliver in particular at high and extremely high speeds (in particular above 1000 m/min).
This problem is solved with a revolving plate and a method with the features of the independent claims.
Sliver generally comprises particles that are bound only incompletely in the inner structure of the sliver. Such particles are e.g., short fibers and dirt particles. Part of these particles are loosened out of the sliver structure under the influence of the forces acting on the sliver in the sliver passage and the loosened-out particles are transported further with only a loose connection to the sliver. The reduction of the total acting forces in accordance with the invention counteracts the undesired loosening out of particles from the sliver.
According to the invention the revolving plate comprises a sliver passage to this end that has such a shape at least on a predominant part or large part of its length that at a given ratio between the supply speed of the sliver and the speed of the revolving plate substantially no force that is tangential relative to the axis of rotation of the revolving plate and acts on the sliver to be deposited occurs along the sliver passage. The movement of an individual element of the sliver results thereby from the vectorial addition of the rotating motion of the sliver passage and the movement of the individual element of the sliver relative to the sliver passage, whose direction is a function of the shape of the sliver passage of the invention.
Furthermore, the settling of particles loosened out of the sliver on the inner wall of the sliver passage is prevented. In the case of the revolving plate of the invention the normal force between these loosely entrained particles and the inner wall of the sliver passage, and therewith also the frictional force, is reduced and preferably minimized. This ensures that the forces transporting the particles through the sliver passage, especially the centrifugal forces, caused by the rotation of the revolving plate, and the friction between the running sliver and the particles are greater than the forces braking the particles, namely, the frictional forces between particles and the inner wall. As a result, the disturbing particles are transported individually and continuously out of the sliver passage and not, as in traditional devices, as closed particle compounds.
The achieving of the advantages of the invention is not associated with a certain speed of the revolving plate nor with a certain supply speed of the sliver. The sole essential feature is that the ratio of these two characteristic magnitudes and the shape of the sliver passage are coordinated with one another. To the extent that the depositing of sliver is designed in such a manner that the ratio between the supply speed of the sliver and the speed of the revolving plate is constant at a change of the supply speed, that is, e.g., during the starting of the depositing of sliver from a standstill, a depositing of sliver that is substantially free of tangential forces is ensured through the sliver passage of the invention independently of the supply speed of the sliver.
The shaping of the sliver passage in accordance with the invention brings it about that the total force acting on the sliver is sharply reduced since in this case the total force results solely from the addition of radial and axial forces.
Although the attempt is made to ensure that the sliver passage is formed in a manner in accordance with the invention over its entire length, it is within the scope of the invention if a deviation from the ideal shape is desired in certain areas, e.g., at the inlet or the outlet in order to take account of the special conditions there.
The invention brings about a reduction of the settling of particles loosened out of the sliver independently of the coefficient of friction between the inner wall of the sliver passage and the particular particles. This applies to individual fibers loosened out of the sliver as well as to dirt particles loosened out of the sliver. The only decisive feature is that the normal force between the particles and the inner wall of the sliver passage is reduced by the invention on account of the extensive elimination of said tangential forces.
In addition, a protective depositing of sliver is ensured by the sliver passage formed in accordance with the invention. The lesser loading of the sliver with forces reduces the danger of wrong drafts. Moreover, the loosening of particles out of the sliver is minimized.
In an embodiment of the invention the sliver passage is designed in such a manner that the center line of the sliver passage is close to or overlays an ideal line at least to a predominant part or a great part, which line runs over the entire length of the sliver passage in such a manner that at a given ratio between the speed of the revolving plate and the supply speed of the sliver the tangential speed, produced by the rotation of the revolving plate relative to the textile machine, of each point of the ideal line is opposingly as great as the tangential component, produced by the transport of the sliver along the center line in the sliver passage, of the relative speed of the sliver relative to the sliver passage at the particular concerned point of the ideal line, The center line coincides in a sliver passage with circular cross section and a uniform wall thickness with the center of gravity line of the sliver passage.
As a rule, the ratio between the supply speed of the sliver and the speed of the revolving plate as well as the depositing radius and the extension of the passage parallel to the axis of rotation of the revolving plate (height) are given. Also, the desired exiting direction of the sliver out of the revolving plate is known. In this instance an ideal line could be calculated by numerical methods that represents a complex, helical spatial curve.
If the sliver passage is shaped in such a manner that the center line of the sliver passage substantially corresponds to this ideal line, the transport of the sliver takes place in a manner that is substantially free of tangential force.
A depositing that is absolutely free of tangential force is not possible since the cross section of the sliver has an areal extent. The actual transport path of an individual sliver element located on the outside of the sliver therefore necessarily deviates from the ideal line. However, the deviation is slight in the customary, relatively thin slivers.
Furthermore, the movement line, that is, the line that the center or center of gravity of a sliver cross section actually moves through during its motion in the sliver passage, can deviate from the center line of the sliver passage in partial sections of the sliver passage. However, the tangential forces remaining as a result of the deviation of the movement line from the centerline are slight.
It is also possible that the sliver passage is shaped in such a manner that the actual movement line of the sliver corresponds substantially to this ideal line. However, this assumes that the movement line is determined in advance, e.g., by a computer simulation. The center line of the sliver passage and the actual movement line can coincide, which, if this is accepted or calculated, favors an easer shaping in accordance with the invention of the sliver passage.
It is especially advantageous if the center line of the sliver passage is composed of successive curve sections in space and each curve section consists of an elementary geometric shape. Suitable geometric shapes are, e.g., helical line sections, circular arcs, elliptical arcs or straight-line sections. Such a sliver passage can be manufactured relatively simply with current machines without the functionality of the invention, namely, the guiding of the sliver substantially along the ideal line without a substantial tangential component of an individual sliver element, being relevantly impaired.
If the curve section carrying the entrance opening is a straight-line section the axial extension of the revolving plate, that is, the over-all height, can be readily adapted to the particular requirements determined by the geometry of the sliver depositing device. For this, only the length of the straight section has to be changed. The geometry of the complexly curved and/or helical curve section can remain unchanged.
In a particularly preferred embodiment the curve sections consist exclusively of level geometric shapes. Level shapes in this connection are all shapes that can be represented in one plane.
It is especially advantageous if the curve sections merge into each other without bends at the transitional areas. In other words, the curve sections have a common tangent at the transitional areas.
A revolving plate in accordance with the invention can be manufactured in an especially simple manner if the centerline preferably has three to twelve and especially preferably four to eight directly successive curve sections that are circular arcs and if adjacent circular arcs have different radii and/or are located in different planes.
It is furthermore advantageous if the center line has an outwardly facing radial component viewed from the top on the upstream opening section of the exit opening relative to the axis of rotation of the revolving plate. This ensures that particles separated out of the sliver are accelerated outward by the radial forces upon reaching the exit opening and are removed in this manner.
The removal of particles loosened out of the sliver is also favored if all tangents of the section of the center line, which section extends in a top view over the opening area of the exit opening, form an angle of less than 45° and preferably less than 30° with the press surface. In this instance the center line intersects the press surface at an acute angle, wherewith the exit opening of the sliver passage assumes the shape of an elongated kidney.
A particularly preferred feature, which also represents an independent aspect of the invention, is that the opening area of the exit opening in the lower view is larger than the remaining surface of the sliver passage, which surface is visible in the lower view. This opening area is advantageously approximately twice as large or larger in comparison to said closed surface. The kidney shape of the exit opening is considerably more pronounced in these embodiments compared to the known sliver passages. In the known sliver passages this opening area of the exit opening is always smaller than the remaining surface of the sliver passage, which surface is visible in the top view.
Opening angle β of the exit opening of the sliver passage, viewed from the bottom of the revolving plate, is more than 45° and preferably more than 60°, which is associated with the previous aspect of the invention but can also be viewed as an independent aspect of the invention. Even larger opening angles of 80° or 90° or even larger are possible.
In as far as the center line, viewed in the direction of transport has a monotonically, preferably a strictly monotonically, falling gradient relative to a normal plane of the axis of rotation of the revolving plate, the running sliver is deflected in an especially protective manner.
Furthermore, a protective depositing is brought about if the center line of the sliver passage, viewed in the direction of transport, has a monotonically, preferably a strictly monotonically rising interval to the axis of rotation of the revolving plate. This ensures that at least one component of the centrifugal force acting on the particles faces parallel to the direction of transport and thus brings about or at least supports the transport of the particles.
The sliver passage of the invention can basically have a cross section that remains the same in the longitudinal course or that changes. However, a constant cross section is preferable. Even the shape of the cross section is not essential for the invention. Round cross sections are especially preferred. Even oval cross sections can be advantageous.
The sliver passage of the invention can be designed in one part or in several parts. In an embodiment designed in several parts and in particular in two parts, e.g., the mouth of the sliver passage, that empties with the exit opening into the plane of the press surface, can be designed as a separate part and integrated, e.g., cast into the bottom of the revolving plate, whereas the remaining, significantly longer part of the sliver passage is formed in one piece and inserted with the mouthpiece.
In the method of the invention the deflection of the sliver in the sliver passage takes place in such a manner that substantially no tangential forces are exerted on the sliver relative to the axis of rotation of the revolving plate and as a result the sliver passage minimizes frictional forces acting on the sliver. The longitudinal tension is selected in such a manner that the remaining frictional forces can just barely be overcome. The longitudinal tension is accordingly selected sufficiently low to avoid a spinning start draft to the extent possible. The longitudinal tension can be produced by mechanical or pneumatic means but it is preferably that, as is known from the state of the art, the sliver is pressed by the press surface onto already deposited sliver and is drawn out of the sliver passage by the contact with the deposited sliver. During this action the rotation of the revolving plate relative to the sliver container is utilized in a simple manner.
The longitudinal tension can be selected by adjusting the pressing force acting on the sliver exiting from the exit opening and/or by adjusting the relative speed of the sliver exiting from the exit opening to the container. The pressing force can, e.g., be regulated in the case of container bottoms raised outside of the containers by different lowering paths of the container bottom during filling.
It is especially advantageous if the longitudinal tension is selected in such a manner that the spinning start draft of the sliver produced by the longitudinal tension is less than 1.02 and preferably less than 1.01.
Advantageous further developments of the invention are characterized by the features of the subclaims.
Further advantages of the invention are described in the following exemplary embodiments.
The known revolving plate 1 according to
The sliver enters parallel to axis of rotation 11 in the area of entrance opening 5 into sliver passage 2, where it is deflected and leaves the sliver passage for being deposited in container 10 through exit opening 6 located in the plane of press surface 7. Interval 9 between press surface 7 and container 10 is selected to be small so that deposited fiber can not swell out of container 10.
Sliver passage 2 consists of two circular arcs 15, 16 that merge directly into one another and are arranged in different planes. A sliver element that is passing through is exposed in the area of circular arc 15 to strong tangential forces (tangential relative to axis of rotation 11). This heavily loads the sliver and furthers the coming loose of particles out of the sliver. These loosened-out particles tend to settle with preference in circular arc 16 in the area of the exit opening on the inner wall of sliver 2. These deposits can form a particle clump of considerable size (so-called mice) during the operation of the depositing of sliver. Such particle clumps come loose from time to time from the inner wall of the sliver passage and can then pass into the sliver container, which is problematic for the further processing of the sliver. Furthermore, these settled particles can damage the sliver being conducted through.
Revolving plate 1 of the invention differs from revolving plate 1 shown in
The removal of particles loosened out of the sliver (the so-called mice in the case of particle accumulations) is also favored if all tangents ML form an angle of less than 45° and preferably less than 30° from the section of the center line extending in a top view over the opening area of outlet opening 6 with the press surface. Tangents ML1, ML2 intersecting the plane of press surface 7 at angle α1 and α2 are shown by way of example.
In relation to a normal plane to axis of rotation 11 of the revolving plate, center line 14 has an infinite rise in the area of entrance opening 5 which rise constantly decreases up to exit opening 6 viewed in the direction of transport.
Tangents ML of center line 14 have a radial component MLrad relative to axis of rotation 11 of revolving plate 1 at opening section 6a of kidney-shaped exit opening 6, which section 6a is located upstream viewed from above (see
It can also be gathered from
It can also be seen from
The shape of sliver passage 2 shown in
This brings it about that an element E of the sliver running through passage 2 is not subjected to any substantial tangential speed or acceleration. Therefore, no substantial tangential forces act on an element E of the sliver. The resulting movement VFB-TM of an element E of the sliver has substantially only a radial component VFB-TM rad and an axial component VFB-TM ax. The addition of these components yields velocity vector VFB-TM of element E at point P.
Thus, an element E moves radially and in a straight line away from axis of rotation 11 of revolving plate 1 relative to the textile machine. Ideal line 12 can be digitally calculated at the given geometric dimensions. Ideal line 12 runs thereby over the entire length of sliver passage 2 in such a manner that at a given ratio between the supply speed of the sliver and the speed of revolving plate 1 the tangential speed VBK-TM tang of each point P of ideal line 12, which speed is produced by the rotation of the revolving plate relative to the textile machine, is opposingly equally as great as tangential component VFB-BK tang of the relative speed of the sliver relative to the sliver passage at the particular point P of the ideal line, which latter speed is produced by the transport of the sliver in the sliver passage. The sliver passage can then be shaped in such a manner that center line 14 of sliver 2 is substantially congruent to or conforms to ideal line 12. If it is assumed that the center of gravity line of the sliver moves substantially along center line 14 through sliver passage 2, the sliver experiences only slight or negligible tangential forces in spite of its extent relative to the cross section.
According to
Finally,
Sliver passage 2 according to
The present invention is not limited to the revolving plate shown and described. Modifications are always possible within the scope of the patent claims. For example, it can be provided that sliver passage 2 has a number of circular arcs that differs from the exemplary embodiment shown. This number is advantageously four to eight circular arcs since at such a number a simple manufacture as well as an approximation of the center line to the ideal line is ensured. The invention can also be used with round cans that are rotated during filling as well as with rectangular cans that are put in translatory movement during filling.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 034 408.6 | Jul 2004 | DE | national |
