|Title of Invention||
A DEVICE FOR DETECTING THE MASS OF FIBRE MATERIAL AT THE ENTRANCE OF A SPINNING BOX IN A SPINNING MACHINE
|Abstract||The invention provides a device for detecting the mass of fibre material at the entrance of a spinning box in a spinning machine, characterized in that a measuring element for measuring fibre material fed to the spinning box is fixed on a feed trough (1) rotatably mounted about an axis (2) and having a guide surface (3) for the fibre material (5), whereas said guide surface is arranged approximately tangential to the circumference of a feed roller (4) of the spinning box in the rotor spinning machine for pressing the incoming fibre material against the feed roller.|
|Full Text||The invention relates to a device for detecting the mass of fibre material at the entrance of a spinning box in a spinning machine.
Known rotor spinning machines, for example, merely comprise at the entrance to the spinning station or spinning box a so-called feed trough, which presses the incoming fibre material, which is supplied in the form of a strip, against a feed roller, so that the fibre material is drawn over the feed trough by the feed roller. The feed trough can be constructed as a type of lever or flap which is rotatably mounted and extends in the vicinity of the feed roller approximately tangentially thereto. After the feed roller, the fibre material is taken up by a separating roller where the fibres are separated.
If the thickness or the mass of the fibre material is to be measured in the vicinity or region of the spinning station, then it is necessary, for example, to arrange known measuring devices such as measuring hoppers etc., upstream or downstream of the spinning station. However, this can only be provided where space is available for a measuring device along the supplied fibre material. If this space is available, a measuring device can be provided. However, this generates resistance in the fibre material which needs to be overcome and which can influence the fibre material in an unexpected manner.
It is therefore the object of the invention, as is characterised in that patent claims, to provide a device which prevent the above-mentioned disadvantages and allow the mass of fibre material to be measured.
This object is actained in that the mass of fibre material is detected in the region of a feed roller of a spinning station of a rotor spinning machine. A device suited to this end comprises a measuring element on the* feed trough, which measuring element is constructed to transmit a signal corresponding to the mass of fibre material on the feed trough. This measuring element can be constructed on Che one hand so that it detects movements or positions of the feed trough per se which are caused by fluctuations in the mass or thickness of the fibre strip and which are converted into a measurement signal. On the other hand, a measuring element which supplies a measurement signal can be integrated in the feed trough. Measuring elements of this type can trace the surface of the fibre material, can follow the irregularities and can effect deflections which can be converted into information relating to a path or a pressure. Accordingly, the measuring elements comprise tracer elements which are connected to a pressure measuring element or path measuring element. Resistance strain gauges, optically or capacitively operating path recorders or pneumatically or piezoelectrically operating pressure recorders can be more particularly provided as path measuring elements.
The advantages obtained in this manner can be seen, for example, in that, on the one hand, the fibre material is required to pass through fewer elements, each of which may have an unfavourable effect on the material, and on the other hand the spinning machine also requires one element less, so that the spinning station and its environment remains more accessible. A further advantage can be seen in chat Che generated measurement signals are particularly suitable for concrolling Che spinning sCation in such a manner that the spinning station can be-directly regulaced, so chac mass fluctuations in Che fibre material can be avoided in che spinning scacion per se by way of a suitable control inCervencion. The possibility of examining the
quality of the fibre material prior to processing into yam is also made available in this manner.
Accordingly, the present invention provides a device for detecting the mass of fibre material at the entrance of a spinning box in a spinning machine, characterized in that a measuring element for measuring fibre material fed to the spinning box is fixed on a feed trough rotatably mounted about an axis and having a guide surface for the fibre material, whereas said guide surface is arranged approximately tangential to the circumference of a feed roller of the spinning box in the rotor spinning machine for pressing the incoming fibre material against the feed roller.
The invetrtion is explained in further detail in the following with the aid of examples and with reference to the attached drawings, in which:
Figs. 1 to 8 each show a particular embodiment of the device according to the invention, and
Fig. 9 is a graph illustrating the path of the measurement values and derived signals.
Figure 1 shows a device with a feed trough 1, which in this case is mounted so as to rotate about an axis 2 within a restricted range and comprises a guide surface 3 for fibre material 5, which surface is arranged approximately-tangential to the circumference of a feed roller 4 so long as the feed trough is in an operative position. Connected downstream of the feed roller 4 is a separating roller 6. In addition, guides 7 for the fibre material are provided upstream, which guide the fibre material onto the feed trough l. Also arranged on the feed trough 1 as a measuring element is an angle transmitter 8, which determines an angle which is proportional to the thickness or mass of the fibre material 5 between the guide surface 3 and the feed roller 4. The angle transmitter 3 is connected via a line 10 Co an evaluating unit 11. This has the task of supplying the measuring element with energy, of detecting and amplifying signals from the measuring element and of offering the possibility of calibration, zero point adjustment, normalisation of the signals and/or compensation of interferences. In the same context, it would be conceivable to provide a displaceable feed trough 1 in place of a pivotable feed trough. A path would then need to be recorded rather than an angle.
Figure 2 shows a further embodiment in which a measuring element 12 is fitted beneath the guide surface 3 in the supply trough 1. The measuring element 12 comprises a tracer element 13 and an evaluation circuit 14. In this case, the tracer element 13 is constructed as a resilient measuring bar with resistance strain, gauges fitted thereon in a bridge circuit. The evaluation circuit is coiinected to the bridge circuit and comprises, for example, an amplifier. Here too, the output signal can be transmitted via a line 15 to an evaluation unit.
Figure 3 is a plan view of the supply trough 1 in which an outlet duct 16 for the fibre material is particularly visible. The outlet duct 16 is defined laterally by projecting limits 17. The guide surface 3 of the feed trough 1 comprises a window 18, through which a tracer element 13 can project.
Figure 4 shows an embodiment in which the tracer element 13 is connected Co a lever system 19, which in turn cooperates with a path recorder 20. In this case, the tracer element
20 is loaded by a spring, not shown, which presses the
tracer element against the fibre material 5.
Figure 5 shows an embodiment with a projecting tracer element 21, which is arranged opposite an additional guide 22 also arranged on the feed trough 1. The tracer element
21 acts upon a spring 23, which is provided with resistance
strain gauges. These are again arranged in a bridge
circuit. An evaluation circuit 24 with an amplifier is
Figure 6 shows an arrangement of the tracer element: 21 comparable to that of Fig. 5, although in this case the tracer element 21 cooperates with a lever system 25, which can amplify or reduce the deflections of the tracer element 21 depending on its design. Here too, a path recorder 26
is provided for detecting the deflections of the lever system 25.
Figure "? shows a system which operates according to a
passive pneumatic measuring principle. It therefore
comprises an aperture 27 in the guide 22 leading to the
fibre material. The aperture 27 acts as a measuring
element and is connected via a line 28 to a pressure
converter 29. The line 23 is also connected via a pilot
nozzle 30 to a supply line 31. The pressure converter 29
can thus be connected to a pilot chamber as is already
Indian known from the/Patent Application No.902AlAS/96. In .this
case, tlae pressure in the supply line 31 is preferably the
same for all feed troughs connected thereto.
Figure B shows a system with a capacitively operating measuring element 4 2, which is arranged on Che guide 7 directly upstream of the feed roller 4. The capacitance of the measuring element is built into a bridge circuit, which is in turn connected to an evaluation unit 41 of now known type.
The method of operation of the different systems is as follows: In the embodiment according to Fig. 1, the position of the feed trough 1, which is expressed by the angle 9, provides a measurement for the thickness or mass of the fibre material 5. In this case, it is necessary for the feed trough 1 to be spring-loaded and mounted so as Co be easily displaceable. A signal, which expresses the angle 9, is transmitted via Che line 10 to the evaluation unit 11, which displays the signal or prepares it in such a manner chat it can be used for a form of control or monitoring which takes the angle 9 into account.
In the embodiment according to Fig. 2, an optimum operating point for the measurement system is sought by adjusting the distance between the feed trough 1 and the feed roller 4
and the feed crough 1 is Chen fixed in this position. The fibre material therefore only moves the tracer element 13, which bends a measuring bar to a greater or lesser degree. The bending is detected in a manner known per se by the resistance strain gauge's.
Also in the embodiment according to Fig, 4, only the tracer element 13 moves and this in turn moves a lever 40, whose deflection is detected.
ComparEible processes occur in the etribcdiments according to Figures 5 and 6, with the difference that in these cases it is no longer necessary to adjust the position of the feed trough 1 relative to the feed roller 4. In this case, it is necessary to adjust the position of the guide 22 and its distance from the guide surface 1 in order to obtain the optimum operating point. To this end, means are provided which are not illustrated but are known per se.
In the embodiment according to Fig. 1, it is also necessary to adjust the position of the guide 22. However, in this case the pressure in the line 31 and the size of the nozzle 30 also plays a part in obtaining an optimum method of operation.
In the embodiment according to Fig. 8, the feed trough 1 can be arranged so that it is fixed in position. The mass of the fibre material 5 supplied as a fibre strip is measured as close as possible to the feed roller 4 in known manner.
The systems illustrated in Figures 1 to 8 have different characteristics, as is shown in Figure 9, In Fig. 9, values for the mass of the fibre material are indicated on the axis 32 and values of an electrical signal, for example in volts or amperes, of a frequency or of a digital signal are indicated on the axis 33 and values corresponding to a
physical measurement, e.g. values corresponding to an angle, a pressure, a force or a path are indicated on the axis 34. As the straight line 35 indicates, ic can be assumed Chat a linear correlation exists between the last-mentioned values and the values of electrical signals. In contrast, ic depends upon the measurement principle whether a linear correlation exiscs between the values corresponding to a deflection and Che values corresponding Co a mass. The lines 36 and 37 illuscrate the correlation in a system according to Fig. 1 and systems according to Figures 4, 6 and 8. A curve 38 illustrates the correlation in Che systems according to Figs. 2 and i5, whilst the line 39 illustrates Che correlacion in pneumatically operaCing syscems according Co Fig. 7. From Chese characceristic curves 36 - 39 it is possible to select a working range within which the fluctuacions in mass should approximately fall by correspondingly adjusting Che feed trough l relaCive Co Che feed roller 4 or Che guide 22 relaCive Co Che guide surface 1,
1. A device for detecting the mass of fibre material at the entrance of a spinning box in a spinning machine, characterized in that a measuring element for measuring fibre material fed to the spinning box is fixed on a feed trough (1) rotatably mounted about an axis (2) and having a guide surface (3) for the fibre material (5), whereas said guide surface is arranged approximately tangential to the circumference of a feed roller (4) of the spinning box in the rotor spinning machine for pressing the incoming fibre material against the feed roller.
2. The device according to claim I, wherein the measuring element is a measuring bar.
3. The device according to claim 1, wherein the measuring element is an angle transmitter.
4. The device according to claim 1, wherein the measuring element is a capacitor.
5. The device according to claim 1, wherein the measuring element is a pneumatic converter.
6. The device according to claim 1, wherein a guide (22) for the incoming fibre material (5) is fixed to the feed trough.
7. The device according to claim 6, wherein the guide is constructed and arranged to cooperate with a measuring element located opposite of the said guide (22).
8. A device for detecting the mass of fibre material at the entrance of a spinning box in a spinning machine substantially as herein described with reference to the accompanying drawings.
|Indian Patent Application Number||1068/MAS/1996|
|PG Journal Number||08/2007|
|Date of Filing||18-Jun-1996|
|Name of Patentee||USTER TECHNOLOGIES AG|
|Applicant Address||WILSTRASSE 11 CH-8610, USTER|
|PCT International Classification Number||D01H13/32|
|PCT International Application Number||N/A|
|PCT International Filing date|