WO1992009517A1

WO1992009517A1 - Measurement of material length

Info

Publication number: WO1992009517A1
Application number: PCT/GB1991/002102
Authority: WO
Inventors: Richard Edward Davies
Original assignee: Techni Drive Ltd.
Priority date: 1990-11-28
Filing date: 1991-11-27
Publication date: 1992-06-11
Also published as: GB9025933D0; TW200441B

Abstract

An apparatus for measuring the length of material wound on to a former to form a package which comprises means for measuring the rotation of the package on the former, means for measuring the diameter of the package and means for combining the measurements so as to determine the length of material wound on to the package; a method of winding using such apparatus; and material when so wound.

Description

DESCRIPTION "MEASUREMENT OF MATERIAL LENGTH"

The present invention relates to the measurement of the length of flexible material wound on to a former. More particularly it relates to apparatus for measuring the length of flexible material, especially glass fibre, wound on a former, especially when the former is mounted in a spinning frame.

Apparatus is known for winding flexible material on to a former whereby the former is driven and the material is pulled from a supply package by rotation of the former. Between the former and the supply package the material may pass through a ring which slides in a guiding channel arranged around the package being formed. Such an arrangement imparts a twist to the material being wound.

Typically in such apparatus, the former is gripped by a mandrel driven by belts or gears from a common shaft driving a number of mandrels. Material tension causes the ring to rotate in the guiding channel as the former rotates. The length of material wound on to the former depends on the rotation of the ring relative to the former. Variations in the material tension, relative friction between the material and ring, relative friction between ring and guiding channel, material winding speed, tension and package diameter influence the rotation of the ring relative to the former.

It is highly desirable to know the length of flexible material wound on a former. Known methods have included visual estimation of the depth of the total of layers of flexible material wound on the former by viewing the outer edge of the depth of material, from a set point, against a scale mounted on

SUBSTITUTESHEET the side of the former remote from the set "viewing" point. Such methods have not been found to be particularly accurate.

Accurate knowledge of the length of flexible material wound on a former is particularly important in many circumstances, particularly, for example, when the resulting wound package of flexible material is to be used in a subsequent manufacturing process.

If, for example, the flexible material is glass fibre, lack of knowledge of the length of the glass fibre on a wound package of it leads to problems if the estimated length is too great or too little. Usually several wound packages of glass fibre are used in the relevant apparatus for manufacturing a desired product. If the length of glass fibre on one or more of the packages is greater than is required in the manufacture of the desired product, the excess length is waste product. While the waste product can be reprocessed, there is a cost involved in such reprocessing which may make it uneconomic. If, on the other hand, the length of glass fibre on any one package is less than has been estimated, greater problems arise. In such a case the package "runs out" before the manufacture of the desired product is complete. It is not practical, particularly in the case of glass fibre, to stop the manufacturing process, replace the empty package by a new package and tie the leading end of the glass fibre from the new package to the trailing end of the glass fibre from the previous package.

Attempts have been made to measure the length of flexible material, for example glass fibre, by passing the lexible material over or round a wheel which is intermediate the supply package of flexible material and the former on to which it is to be wound. Such a method does, however, involve contact with another surface, which is disadvantageous.

It has now been found possible to measure the length of a flexible material wound on to a former by use of apparatus which does not require contact means and in a manner which is more accurate than known methods.

According to the present invention there is provided an apparatus for measuring the length of material wound on to a former to form a package which comprises means for measuring the rotation of the package on the former, means for measuring the diameter of the package and means for combining the measurements so as to determine the length of material wound on to the package.

In accordance with one embodiment of the present invention, there is provided a means for measuring the length of material wound on to a former to form a package, the material passing through a spinning ring intermediate a supply package of the material and the former, the spinning ring being arranged so that it slides with respect to a member associated with a supporting framework before passing on to the former, which comprises means for measuring the rotation of the package on the former, means for measuring the rotation of the spinning ring, means for measuring the diameter of the package on the former at the point of winding and means for combining the measurements so as to determine the length of material wound on to the package on the former. The means of measuring the rotation of the ring may be a photo-electric sensor.

It is preferred that the package diameter is measured without mechanical contact with the surface of the package.

When the means for measuring the package diameter are positioned so that such measurement does not take place exactly at the point of winding on to the former, it may be necessary to incorporate a compensating factor into the means for combining the measurements as referred to hereinabove. Such a compensating factor is necessary when the package shape being produced by the winding is a truncated cone rather than a cylinder in the region of the measurement of the package diameter and/or the winding of the material on to the former.

Preferably there are means for comparing the determined length of material wound on to the package with a pre-set value in order to control the length of material wound on to the package.

The means for measuring the rotation of the package may be a photo-electric sensor. The means for measuring the diameter of the package may be a transducer, for example a laser transducer or an ultrasonic transducer, for measurement of distance from a fixed point. The transducer output may be modified to provide a value representing the circumference of the package.

There are desirably provided driving means, for example, a motor, to move a movable member to a definable position with respect to the surface of the package. In accordance with one embodiment of the present invention, the driving means for positioning the movable member is a motor which is a stepper motor, the position of the movable member being measured by the number of increments of movement from a known calibration position. The measured value of the position of the movable member in such an embodi ent may be modified to provide a value representing the circumference of the package.

In accordance with another embodiment of the present invention, the driving means for positioning the movable member is an electric motor, the position of the movable motor being measured by a digital or analogue transducer. In this embodiment the transducer output may be modified to provide a value representing the circumference of the package.

Preferably, the driving means is controlled by a photo-electric sensor.

The present invention is in particular applicable to flexible materials which are to be used subsequently in the manufacture of products by means associated with textiles. Among such flexible materials are glass fibres.

The present invention will now be further described by way of example with reference to, but in no manner limited to, the accompanying drawings, in which:-

Figs.l and 2 show in perspective two forms of known apparatus for winding material;

Figure 3 illustrates a means of measuring diameter according to the present invention;

Figure 4 illustrates an alternative means of measuring diameter according to the present invention;

Figure 5 illustrates a means according to the present invention for particularly measuring diameter of a parallel sided package;

Figure 6 illustrates one alternative means, according to the present invention, for positioning the emitter;

Figure 7 illustrates another alternative means, according to the present invention, for positioning the emitter;

Figure 8 illustrates a means of measuring rotation of the spinning ring according to the present invention;

Figure 9 illustrates an alternative means for measuring rotation of the spinning ring;

Figure 10 illustrates a means of measuring rotation of the mandrel/former according to the present invention; and

Figure 11 illustrates a means of totalising length.

The apparatus illustrated in Figure 1 depicts a former 11 mounted on a supporting mandrel 12 which grips the former 11 during the winding operation. Material 13 is pulled through the ring 14 on to the former 11 as the former 11 rotates and is laid initially on the surface of the former 11. Subsequently, it is laid on the surface of the material package 17 as the package 17 builds up. The ring 14 slides in a groove 15 which is held in position around the former 11 by a supporting framework 16. As the former 11 is rotated, the frame 16 is moved in a reciprocating manner in a direction parallel to the axis of the former 11 in such a way that the material is laid in a helical fashion along the surface of the package 17 in a number of layers. The extent of travel of the ring groove 15 may be altered as the package 17 builds up in such a way as to form the optimum package shape for subsequent unwinding.

Typically the final package shape could be cylindrical in part, with the remainder shaped as a truncated cone. The amount of material wound on to the cone depends upon the friction between the ring 14 and the groove 15, the tension in the material being wound, the diameter of the package and the speed of rotation of the former 11.

The apparatus illustrated in Figure 2 depicts an alternative means for winding material on to a former such as can be used for winding material such as, for example, glass fibre. In such an apparatus, the former 21 is mounted on a supporting mandrel 22 which grips the former 21 during the winding operation. The material 23 is pulled through ring 24 on to former 21 as former 21 rotates and is laid initially on the surface of former 21. In this particular form of apparatus, ring 24 is arranged so as to run around a track 25 which is shaped so as to constrain the travel of ring 24 to a circular path. A frame 26 (shown sectioned in part) is moved vertically upwards and downwards so as to lay the material 23 on the former 21 in forming a package.

Figure 3 illustrates a means of measuring the package diameter without mechanical contact with the surface of the package 37. A light emitter 38 is mounted on a movable guided member 132 arranged to slide in a direction, typically, but not necessarily, tangential to the supporting frame outside surface. This member 132 may be driven by an electric motor 133 so as to position the line joining the emitter 38, and detector 39 to be tangential to the package surface. If the light received at the detector increases, the motor 133 is rotated to drive the guided member 132 by rotation of the gear wheel 135 against the linear teeth on the guided member 132, so as to reduce the light received at the detector 39. In this way the control system determines the position of the movable member 132 so that the line of sight 130 is tangential to the surface of the package 37. As the package 37 builds up, by the material being fed via the ring running, in groove or on track 35 on supporting framework 36, the guided member 132 moves to maintain the required amount of light incident on the detector 39 and thus the position of the guided member 132 is controlled to be in relation to the diameter of the package 37. Transducer 136 is used to measure the position of the guided member 132 and provides a signal related to the package diameter.

An alternative arrangement could use a shaft encoder or rotary potentiometer attached to the motor 133 through a gearbox to provide a position signal. In order to compensate for degradation of the optical sensor arising from components ageing in the sensor or transducer or from accumulation of debris over a long period, it is desirable to provide a calibration point consisting of an edge at a position corresponding to a known diameter of a package. Conveniently it could be placed at a point outside the limit of maximum package diameter and used to calibrate the position transducer to compensate for changes in system parameters. Alternatively the known diameter of the former could be used, or an intermediate edge be arranged to be retractable for normal running.

It is possible to use a stepper motor to move the light source to the controlled position. The number and direction of the impulses to the stepper motor would be counted as a measure of the position of the movable member. In such an arrangement, the absolute position would be established by means of a calibration edge mounted at a known travel of the guided member. The emitter would be moved past this position and the resultant change in detected light signal at the calibration point would set a counter to a known value corresponding to the absolute position of the guided member. By counting stepper motor supply pulses, the offset signal with respect to the calibration point would be determined and used as an absolute position signal. An alternative arrangement of the drive motor would consist of a stepper motor or other electric motor operating through a lead screw arrangement for moving the guided member.

In an alternative arrangement, the position of the light emitter and detector would be exchanged.

An alternative arrangement for the photoelectric system would utilise modulated light in order to eliminate the effect of ambient light.

Yet another alternative arrangement of the photoelectric system would employ multi-element emitters and detectors in a balanced relationship so as to improve discrimination and reduce the effects of ambient light.

An alternative means of measuring diameter is illustrated in Figure 4. A photoelectric emitter 48 and detector 49 are arranged in a U-shaped yoke 147 which can be moved towards or away from the package of material on former 41. The yoke 40 may be driven by a leadscrew or, as illustrated, by a rack and pinion 140.

The rack and pinion arrangement comprises rack 141 and pinion 142. The pinion is driven by the electric motor 143 while rack 141 is constrained to move in a linear manner by guide block 144 acting on the surfaces 145 which are inclined so as to guide rack 141. The transducer body 146 is mounted on block 144 and is operated by a linkage 148 connected to yoke 147. The electric motor is controlled to move rack 141 so that the line of light between emitter 48 and detector 49 is always tangential to the surface of the package.

The assembly consisting of yoke 147 and its associated members is mounted on a supporting structure and moves vertically with respect to the point of the material being wound onto the package.

However, if a parallel package is being produced, it may not be necessary to move the yoke parallel to the axis of the package.

In Figure 5 there is illustrated a cylindrical package in a former 61 which draws material 63 from a supply package (not shown) via a fixed guide 164 and a movable guide 64 which is driven at a rate dependent upon the rotational rate of the cylindrical package on the former 61 around its axis 162. Movable guide 64 moves axially in a reciprocating manner in guide 165 so as to lay material on the package in a helical manner, thereby forming a wound package of material.

The photoemitter 68 and detector 69 are arranged to control the electric motor 163, driving through gearbox 165 so as to rotate yoke 167 around axis 169 to a position where the line of spigot 160 is tangential to the surface of the package being wound.

Alternative driving means are illustrated in Figures 6 and 7.

In Fig.6, emitter 68 is spring loaded and can move with respect to transducer 166. The means for moving emitter 68 comprises a fixed housing 161 having an inner rotating nut 162, driven by a suitable motor, which operates to move lead-screw 163. Guidance prevents leadscrew 163 from rotating.

In Fig.7, emitter 78 operates in conjunction with belt 179 which passes over pulleys 179a and 179b and is driven by a suitable motor (not shown) in conjunction with motor gearbox 175.

It is preferred to use a stepper motor but the use of other forms of electrical motor is not excluded.

Figure 8 illustrates a means for measuring rotation of the ring 84 in the groove 85. For clarity, the arrangement is shown without the mandrel, former and package which would normally be present. A light emitter 88 and detector 89 are fixed on the surface of the frame 86 in which two holes are drilled. The alignment is such that light passes from the emitter 88 to the receiver 89 via light path 180 normally but is interrupted by ring 84 twice in each revolution of the ring. A divide-by-two counter is used to obtain the number of revolutions of the ring.

An alternative means of counting the turns of ring 94 (or measuring its rotation) is illustrated in Figure 9. An assembly comprising emitter 98 and detector 99 is placed close to flange 95 of frame 96. Light transmitted by emitter 98 is reflected by flange 95 and detected by detector 99. When ring 94 interrupts the reflected beam, there is a change in the detector output which can be used to count the number of passages of the ring.

Figure 10 illustrates means of measuring the rotation of the mandrel/former. For the sake of clarity, the former and support frame have been omitted. A light emitter 108 and detector 109 are fixed to a stationary machine support in such a way that they are focused on or pointing towards the same point on the shaft surface. A reflective strip 100 is fixed to the drive shaft. Every time the reflective strip passes the common focusing point, the detector output changes. This signal can be used to measure the number of turns of the drive shaft and mandrel which correspond to the turns of the package.

Figure 11 illustrates a measurement system utilising signals from means illustrated in the foregoing Figures.

The turns 234 of the traveller ring 14,24,84,94 are subtracted from the turns 235 of the package in subtracter 227 so that the output pulses represent the differential rotation of package and ring.

The signal 236 obtained from the position transducer 136,146,166 at that time is converted, typically by a shaping circuit 222, and analogue- digital convertor 221, into a digital number or value 223, corresponding to the circumference of the package.

In every complete turn of the package relative to the ring, an output pulse is generated which causes the current measured value of the circumference to be added to an accumulator 228 by adder or addition circuitry 229. The digital representation of circumference 223 will change as the package increases or decreases in size and will correspond to the length of material wound on to the package at each complete turn of the package.

The new digital value in accumulator 228 is compared (in comparator 233) with the scaled digital value corresponding to one length unit. If the content of the accumulator 228 becomes equal or greater than one unit of length, accumulator 230 is incremented and the content of accumulator 228 is set to the value of the remainder obtained after subtracting the scaled value of one length unit from the value obtained after the last addition operation into accumulator 228, so that at the end of each package accumulator 230 contains a digital number corresponding to package length.

A further digital comparator 231 may be used to compare the package length with a preset number equal to the preset required length as contained in register 232, and its output may be used to stop the winding process when the desired length has been wound. The shaping circuit 222 and analogue-digital converter 221 may be replaced by a digital shaping circuit operating on the output of the analogue-digital converter 221, or on a digital measurement of the movable number as described above.

Claims

1. An apparatus for measuring the length of material wound on to a former to form a package which comprises means for measuring the rotation of the package on the former, means for measuring the diameter of the package and means for combining the measurements so as to determine the length of material wound on to the package.

2. An apparatus according to claim 1, for measuring the length of material wound on to a former to form a package, the material passing through a spinning ring intermediate a supply package of the material and the former, the spinning ring being arranged so that it slides with respect to a member associated with a supporting framework before passing on to the former, which comprises means for measuring the rotation of the package on the former, means for measuring the rotation of the spinning ring, means for measuring the diameter of the package on the former at the point of winding and means for combining the measurements so as to determine the length of material wound on to the package on the former.

3. An apparatus according to claim 2, wherein the means of measuring the rotation of the ring is a photo-electric sensor.

4. An apparatus according to any of claims 1 to

3, wherein the package diameter is measured without mechanical contact with the surface of the package.

5. An apparatus according to any of claims 1 to

4, wherein there are means for comparing the determined length of material wound on to the package with a preset value in order to control the length of material wound on to the package.

6. An apparatus according to any of claims 1 to

5, wherein the means of measuring the rotation of the package is a photo-electric sensor.

7. An apparatus according to any of claims 1 to

6, wherein the means of measuring the diameter of the package is a transducer for measurement of distance from a fixed point.

8. An apparatus according to claim 7, wherein there are means for modifying the transducer output to provide a value which represents the circumference of the package.

9. An apparatus according to any of claims 1 to 8, wherein there are driving means to move a movable member to a definable position with respect to the surface of the package.

10. An apparatus according to claim 9, wherein the driving means for positioning the movable member is a stepper motor, the position of the movable member being measured by the number of increments of movement from a known calibration position.

11. An apparatus according to claim 10, wherein there are means for modifying the measured value of the position of the movable member to provide a value which represents the circumference of the package.

12. An apparatus according to claim 9, wherein the driving means for positioning the movable member is an electric motor, the position of the movable member being measured by a digital or analogue transducer.

13. An apparatus according to claim 12, wherein there are means for modifying the transducer output to provide a value which represents the circumference of the package.

14. An apparatus according to any of claims 9 to 13, wherein there is a photo-electric device to control the driving means.

15. method of winding material, which comprises the use of an apparatus according to any of claims 1 to 14.

16. A method according to claim 15, wherein the material is glass fibre.

17. Material obtained in wound form on a former by a method according to claim 16.