This application claims the priority of German Patent Application Nos. 102 42 388.1 filed Sep. 13, 2002 and 103 29 836.3 filed Jul. 2, 2003, the subject matters of which are incorporated herein by reference.
1. Field of the Invention
The invention relates to a method, at a draw frame for fibre slivers, of adjusting the nip line spacing of a drawing mechanism, which has at least two drawing mechanism roller combinations, of which at least one is so mounted that it can be adjusted, wherein each drawing mechanism roller combination consists of at least one driven lower roller and at least one upper roller (press roller) lying on top of the lower roller and so mounted that it can be lifted off, and encompasses an apparatus for carrying out the method.
2. Description of Related Art
In practice, adjustment of the nip line spacings carried out without fibre slivers in the drawing mechanism, that is to say the fibre slivers are drawn off from the drawing mechanism completely and, subsequently, the nip line spacings are adjusted. It is not possible, by that means, to optimise existing drawing mechanism settings whilst using the same fibre material.
In a known appartus (DE-OS 20 44 996), the mountings of the intake and middle lower rollers are displaceable on the frame of the machine so that the extent of the drawing zone can be matched to the particular fibre staple. A tensioning pulley wheel, which is displaceable in a guideway in the frame of the machine, allows the length of the toothed belt to be modified in accordance with the changed spacing between the axes of the middle roller and a guide pulley wheel, brought about by displacement of the intake roller. The middle roller is driven by a further toothed belt. The latter toothed belt is tensioned by a tensioning pulley wheel which is fastened to the machine frame and which can pivot about one axis; as a result, it can also be matched to changed spacings between the axes of the intake roller and middle roller. It is disadvantageous that displacing devices for displacement of the intake roller and the middle roller and additional tensioning devices for re-tensioning of the toothed belts after the displacement operations are necessary, requiring a considerable outlay in terms of construction. In addition, it is disadvant-ageous that a number of work steps are required for the displacement operations and the subsequent re-tensioning operations. The belt tension is destroyed by the displacement process. Where the displacement is carried out manually, spacers are inserted between the mountings, the mountings being pushed against the spacers so that, in this case too, the amount of set-up work is considerable. Finally, the displacement and re-tensioning operations result in a doubling of potential error sources when setting the spacings and belt tensions.
The problem underlying the invention is accordingly to provide a method of the kind described at the beginning that avoids the disadvantages mentioned and that especially allows optimation of specific drawing mechanism settings using the same fibre material.
In an exemplary embodiment of the invention, a method for adjusting nip line spacing in a drawing mechanism of a draw frame for fibre slivers is provided. The drawing mechanism including at least two adjustable mounting devices defining a nip line spacing therebetween, each mounting device including at least one lower roller, at least one upper roller adjustably mounted on top of the lower roller, and at least one pulley wheel, the at least one pulley wheel in driving connection with a driving element. The method includes unlocking at least one of the at least two mounting devices; adjusting the nip line spacing between the at least two mounting devices via the drive element; and relocking the at least two mounting devices.
The fact that adjustment of the nip line spacings is carried out with fibre slivers inserted allows, in accordance with the invention, optimisation of specific machinery-related and/or fibre-related settings of the drawing mechanism using the same fibre material. The optimum extent of the drawing zone is dependent on, amongst other things, the length of fibres (staple length). It is likewise possible to determine and set an optimum drafting value.
The invention also encompasses an advantegous apparatus at a draw frame having a drawing mechanism for the doubling and drafting of fibre slivers, have a drawing mechanism from for accommodating the drawing mechanism, which has at least two pairs of rollers each comprising an upper roller and a lower roller, having means for adjusting the spacing of at least one of the lower rollers in relation to another lower roller, in each case having a mounting for accommodating the lower roller, wherein lower rollers are arranged to be driven by at least one drive element endlessly resolving around pulley wheels, wherein at least one pulley wheel and the tensioned guide element are used for adjusting a slider (mounting), wherein a moving force applied to the pulley wheel or to the drive element can be converted into the adjusting movement for the slider.
The invention will be described hereinafter in greater detail with reference to exemplary embodiments shown in the drawings, in which:
a and 3b show the drive for the intake and middle lower rollers for the draw frame according to
c shows a schematic side view of a toothed belt.
a to 4d show, in diagrammatic form, the sequential procedure for shortening of the preliminary and main draft zones;
a and 5b show the intake and middle lower rollers before displacement (
a and 6b show, in diagrammatic form, an electro-magnetic braking apparatus for a toothed belt wheel;
In accordance with
The attenuated fibre slivers 5 reach a web guide 10 in the exit 4 from the drawing mechanism and, by means of the draw-off rollers 15, 16, are drawn through a sliver funnel 17, in which they are combined to form one fibre sliver 18, which is then deposited in cans. Reference letter A denotes the work direction.
The draw-off rollers 7, 8, the intake lower roller III and the middle lower roller II, which are connected to one another mechanically, for example by toothed belts, are driven by the control motor 19, it being possible, in the process, for a desired value to be specified. (The associated upper rollers 14 and 13, respectively, revolve by virtue of the motion of the lower rollers.) The delivery lower roller I and the draw-off rollers 15, 16 are driven by the main motor 20. The control motor 19 and the main motor 20 each have their own controller 21 and 22, respectively. Control (speed-of-rotation control) is carried out in each case by means of a closed control loop, a tachogenerator 23 being associated with the control motor 19 and a tachogenerator 24 being associated with the main motor 20. At the intake 3 of the drawing mechanism, a variable proportional to the weight of the fibre slivers 5 fed in, for example their cross-section, is measured by an intake measuring element 9 known, for example, from DE-A- 195 37 983. A central computer unit 26 (control and regulation device), for example a microcomputer with a microprocessor, sends a setting for the desired value for the control motor 19 to the controller 21. The measurement values of the two measuring elements 9 and 25 are sent to the central computer unit 26 during the drawing process. The desired value for the control motor 19 is determined in the central computer unit 26 from the measurement values of the intake measuring element 9 and from the desired value for the cross-section of the delivered fibre sliver 18. The measurement values of the exit measuring element 25 are used for monitoring of the delivered fibre sliver 18 (delivered sliver monitoring). By means of this control system, it is possible for variations in the cross-section of the fibre slivers 5 fed in to be compensated, and for the fibre sliver to be made more uniform, by appropriately regulating the drafting process. Reference numeral 27 denotes a display monitor, 28 an interface, 29 an input device, 30 a pressure rod and 31 a memory.
In accordance with
Displacement of the sliders 35a, 35b; 36a, 36b at the same time causes the mountings 33a, 33b; 34a, 34b and, as a result, the lower rollers II and III, respectively to be displaced and moved in directions C, D and E, F, respectively. The associated upper roller 13 and 14 are correspondingly moved (in a manner not show) in directions C, D and E, F, respectively. By that means, the nip line spacings between the roller combinations are modified and set.
Locking of the sliders 35a, 35b; 36a, 36b is accomplished by means of a catch device, stopping device or the like (see
In accordance with
In operation, that is to say when the fibre slivers are running in direction A, the toothed belt 47 moves in direction G. Starting from the toothed belt wheel 47 arranged on the drive motor 19, the toothed belt 47 runs successively over a toothed belt wheel 45, a smooth guide pulley wheel 46, the toothed belt wheel 40 (roller-driving pulley wheel for the lower roller III), the toothed belt wheel 41 (roller-driving pulley wheel for the lower roller II), a smooth guide pulley wheel 42 and a toothed belt wheel 43. As shown in
The toothed belt wheels 40, 41 are associated with the mountings 34a and 33a, respectively, whereas the guide pulley wheels 42, 46 are attached to the sliders 35a and 36a, respectively, in a manner allowing rotation. Because of the rigid attachment between the mounting 34a and the slider 36a and between the mounting 33a and the slider 35a (for example, by means of bolts), there are associated with the lower rollers II and III, in each case, one toothed belt wheel 40 to 41 and one guide pulley wheel 46 and 42, respectively. The toothed belt 47 runs around the pulley wheels 40, 46, on the one hand, and round the pulley wheels 41, 42, on the other hand, in a mirror-reflected arrangement (see
The zone between the pairs of rollers 13/II and 14/III is designated VV (preliminary drafting) and the zone between the pairs of rollers 12/I and 13/II is designated HV (main drafting) (see
a) The slider 35a is unlocked. A pulley wheel, for example the toothed belt wheel 44, is stopped so that there is no possibility of rotation. Stopping may be accomplished, for example, by mechanical or electromagnetic means. As a result the toothed belt 47 is stationary and cannot be moved. The toothed belt wheel 41 is then rotated anti-clockwise, for example manually using a crank or the like, whereupon the guide pulley wheel 42 likewise rotates, clockwise, as a matter of necessity. In the process, the rotary movement of the toothed belt wheel 41 is converted into a longitudinal movement of the slider 35a in direction C, the toothed belt wheel 41 and the guide pulley wheel 42 winding along opposite sides of the stationary toothed belt 47, thereby “shortening”, as it were, the toothed belt 47 at one pulley wheel and “lengthening” it at the other pulley wheel. The length of belt required during that “winding along ” at the toothed belt wheel 41 is made available at the guide pulley wheel 42. The lower roller II is thereby displaced in direction C by means of the slide 35a and the mounting 33a.
The slider 35a is unlocked. The toothed belt wheel 41 is stopped so that there is no possibility of rotation. As a result the guide pulley wheel 42 is also stopped of necessity. Then, clockwise rotation is brought about by means of the drive motor 19. The toothed belt 47 moves in direction G, likewise “shortening” the belt 47 at one pulley wheel and “lengthening” it at the other pulley wheel. The length of belt actually required between the toothed belt wheels 40 and 41 is made available between the toothed belt wheels 43 and 42. The rotary movement of the toothed belt wheel 44 and the movement of the toothed belt 47 is thereby converted into a longitudinal movement of the slider 35a in direction C. The lower roller II, mounted in the mounting 33a (which is rigidly connected to the slider 35a), is likewise moved in direction C as a result.
In practice, it is often the case that, in accordance with
With regard to the fibre slivers 5 in the drawing mechanism 2, it should be noted that, in the case of shortening of the draft zones VV and HV, a small amount of stretching, in direction B, of the fibre slivers 5IV upstream of the pair of rollers 14/III can occur on displacement in accordance with
a,
5
b show the construction bringing about the displacement of the sliders 36a and 35a. The nip line spacing in the preliminary draft zone VV is lengthened from “a” (
In accordance with
In accordance with
In accordance with
In accordance with
In accordance with
Adjustment of the nip line spacing in the preliminary draft zone VV and/or the main draft zone HV can be carried out with the fibre slivers 5 inserted.
Displacement can be carried out with the upper rollers 11 to 14 in the loaded state.
Displacement can also be carried out with the upper rollers 11 to 14 lifted off. The upper rollers 11 to 14 may be lifted off completely from the lower rollers I to III in the manner shown in DE-OS 197 04 815, the upper roller 14 being swung out on a portal 58 about a pivot mounting 59. However, it may also be sufficient for the upper rollers 11 to 14 to be unloaded and to be lifted off from the lower rollers I to III only to a slight degree such that the fibre slivers 5 are not caught by the pairs of rollers during displacement of the draft zones VV and HV but can slide through the roller nip without being adversely affected.
The invention has been illustrated using the example of the adjustment of the nip line spacings of a drawing mechanism of a draw frame. It likewise encompasses the adjustment of drawing mechanisms of other machines, for example carding machines, combing machines, fly frames and ring spinning frames.
Number | Date | Country | Kind |
---|---|---|---|
102 42 388 | Sep 2002 | DE | national |
103 29 836 | Jul 2003 | DE | national |
Number | Name | Date | Kind |
---|---|---|---|
3869759 | Savageau et al. | Mar 1975 | A |
4768262 | Gunter | Sep 1988 | A |
6088882 | Leifeld | Jul 2000 | A |
6292982 | Breuer | Sep 2001 | B1 |
Number | Date | Country |
---|---|---|
35 32 555 | Mar 1987 | DE |
24 26 429 | May 1975 | EP |
Number | Date | Country | |
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20040098837 A1 | May 2004 | US |