GB2181753A - Spinning apparatus - Google Patents

Abstract

A spinning machine for spinning yarns has a plurality of spinning units (10), and at each spinning unit two slivers (22, 22') emerging from a drawing mechanism (11) run to a junction point (19) and from this point are twisted together to form a yarn. A break detector (21) is associated with each spinning unit and in the event of breakage of one of the two slivers it will recognise sideways displacement of the remaining sliver (22a, 22a') by means one or more scanning sensors e.g. photoelectric sensors 37, 38 and will thus generate a signal leading to breaking of the other sliver. Such scanning devices do not clog up and are easy to clean unlike the prior art electrical switches. <IMAGE>

Description

SPECIFICATION Spinning apparatus This invention relates to spinning apparatus, and in particulartospinning apparatus having meansfor detecting a break in oneoftwosliversthataretwisted together into a yarn.

In conventional spinning apparatus, such as a ring spinner, yarns are produced from two fibre bundles which runtoajunction point after which they are twisted together to form a single yarn. These fibre bundles or slivers generally consist of any nonendless fibres, such as combed wool. The twist ofthe yarn may be produced by conventional means, preferably using a spindle which passes coaxially through a spinning ring on which a traveller pulled by the yarn can rotate. However, it is also possible to use other means to produce the twist and wind the yarn, such as a rotating spinning pot, a flyer spindle orthe like. Each point ofthe spinning apparatus where a yarn is produced is referred to as a spinning unit.

In a known spinning apparatus of this kind (German OLS 30 21 614) each spinning unit is associated with a breakdetectorwhich has two deflectable members acting as electric switches between which the yarn is passed. If one of the two slivers breaks, the sideways movement of the remaining sliver running from the drawing mechanism to the spindle causes one ofthe two members to be deflected and as are- su It a switching signal is generated to act as a break agesignal.This causesthe remaining yarn to be set ered by means of a severing device. This severing of the remaining yarn is desirable since breakage of only one of the two slivers generally does not inter fere with the running ofthe remaining sliveratthe spinning unit.This would result in a yarn being spun which was thinner and, in the case of two equal slivers, only half the proper thickness. This defect would be likelyto lead to breakages oftheyarn and defective goods during subsequentfurther processing oftheyarn.

The deflectable members producing the breakage signal must be capable of moving very easily and de signedto be reliable in operation.Afterthe breakage of a sliver the switching contacts are pressed against each otherwith only a small force and musttherefore be very sensitive. However, the switching contacts have a tendency to pickup fly and even slig htcon tamination with fly will give rise to a danger of electrical failure ofthe switching contacts. Moreover, the contactsaredifficulttoclean and the cleaning operation presents a risk of injury.

According to the invention there is provided spinning apparatus comprising a spinning unit, said spinning unit having a drawing mechanism and a twisting mechanism wherein, in use, two textilefibre bundles are drawn from the drawing mechanism as untwisted spaced apart slivers, said slivers converging to a junction point after which they are twisted together to form a yarn which runs to the twisting mechanism, said spinning unit further comprising a breakdetector which, in the event of breakage of either of the two fibre bundles, detects the sideways displacement of the remaining fibre bundle running from the drawing mechanism to thetwisting mechanism and triggers a breakage signal, said break detector comprising two sensors which scan the two possible paths ofthe remaining fibre bundle.

Preferablythesensors are photoelectric sensors and conveniently may comprise a lig htscanner advantageously having at least one optical device.

Photoelectric sensing devices may sense a breakage without contact and are less prone to contamination and do not tend to accumulate fly. Additionallythey are easyto clean, for example by means of portable blowers. Thus, sensing devices of this kind can readily be integrated in one or more smooth housings on which fly does not tend to accumulateto any significant degree.

In a preferred em bodiment the two sensors comprise light barriers, preferably one-way light barriers or reflex light barriers. In one-way light barriers the light emitters and the light receivers are located opposite one another whereas in reflex light barriers the light emitters and light receivers are arranged side by side and directed onto a reflector which is located opposite them and at a spacing. The use of light barriers as contactless sensors also has the advantage, interalia, that if in spite of everything the light emitter or receiver or possibly the reflector should become soiled in such awaythatbreakageof a sliver is simulated, yarn breakage would be indicated or initiated and the attendant would then have his attention drawn to the soiling of thins sensor and would be able to clean it.

In another embodiment, the sensors may be reflex scanners. When constructed as a reflex scanner each sensor has a light emitter and a light receiver. The two light emitters of the sensing device are arranged so that their light paths extend in such a way that in the event of breakage of a sliver the remaining sliver would be caught in one of the two light paths of these light emitters and consequently light irradiated by the light emitter in question would be reflected to the associated light receiver, so thatthe latter would detect the presence of this sliver in the light path ofthe light emitter. The photoelectric sensors may preferably be photoelectronic sensors and also have the advantage that they need not have any mechanical moving parts and are simple and cheap to produce and extremely reliable.

Since a relatively long period oftime may often elapse before a yarn breakage is repaired, or in many cases the breakage oftheyarn is not repaired until afterthefilling ofthespools and during thistimethe slivers emerging from the drawing mechanism ofthe spinning unit in question cannot be twisted to form a yarn, it is advantageous if the delivery of slivers from the drawing mechanism is automatically interrupted at the spinning unit in question following the breakage of a sliver. This can be achieved by having a yarn severing devicefor clamping, severing, tearing or similarly breaking the yarn and/or a slubbing stop device, which can be controlled buy a breakage signal.

The yarn severing device serves to sever the yarn which is still present at the spinning unit in question after breakage of one ofthe two slivers has occurred.

This severing may, for example, be effected mech anically by means of a cutting device or electrically by means of a hot filament or in some other suitable way,for example by clamping the yarn, since clam- ping the yarn will produce breakage as the yarn is no longer being delivered to the winding device. A slubbing stop device stops the advance ofthetwo slivers (slubbings) running into the drawing mechanism ofthe spinning unit in question by some suitable method, e.g. by clamping, opening the drawing mechanism orthe like.

Some embodiments ofthe invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic front view of part of a spinning unit of a ring spinning machine (not shown in detail),whilst part of the electronic equipment of this machine for automatically stopping the spinning of the yarns in response to photoelectric sensing devices is shown in the form of a block diagram, Figure2 is a diagrammatic plan view of the sensing device of the spinning unit shown in Figure 1, Figure 3 shows an alternative embodiment ofthe sensingdeviceshown into Figure2.

The spinning unit 10 of a ring spinning frame shown in part in Figure 1 has a drawing mechanism 11 having a piuralityof pairs of rollersfordrawing two slivers 17, 17' running side by side at a spacing from each other; onlythe pairofdelivery rollers 14of the drawing mechanism 11 being shown in Figure 1.

The bottom roller 15 ofthis pair of delivery rollers 14 may be formed by a lowercylinder extending over virtuallythe entire length ofthe relevant side ofthe spinning machine, as is usual in spinning machines, and having a respective upper roller 16 pressed onto it at each spinning unit.The two individual slivers 17, 17' running through the drawing mechanism areguided at a lateral spacing from each other by sliverguides (not shown) and after leaving the pair of delivery rollers 1 4they converge to a junction point 19 located just above a break detector in the form of a photoelectric sensing device 21 having two light barriers 37,38 (Figure 2). Thetwo slivers 22,22', emerging as yet untwisted from the pair of delivery rollers 14, are twisted togetherto form a yarn 23 beyond the junction point 19. The yarn 23 passes through the photoelectric sensing device 21 andimmediatelyafter- wards passes th rough a yarn severing device 24 which may, for example, be in the form of a cutting device with two blades.This yarn severing device 24 may be electrically operated and the yarn 23 is cut through when the device is actuated. This actuation is triggered by the sensing device 21 when it detects a break. As long as the yarn severing device 24 has not been actuated the yarn 23 passes through itwithout being cut. The yarn then passes through a yarn guide 25 mounted above a spindle and at a spacing therefrom and then, forming a balloon ofyarn, runs to a rotating spindle 26 on which a sleeve 27 is releasably fitted on which the yarn 23 is wound to form a wound body of yarn 29.On its way from the yarn guide 25to the spindle 26 the yarn 23 passes through a traveller 30 which, puiled by the yarn, rotates on a spinning ring 31 through which the spindle 26 passes coaxially. This spinning ring 31 is situated on a ring rail 32 which performs lifting movements for displacing the yarn 23 on the sleeve 27 to form the wound body 29.

If one ofthe two slivers 22,22' breaks, the other sliver will performs a sideways movement and thus move into the light beam of one ofthetwo light barriers 37,38 and is then twisted on its own to form a yarn. In the drawing,this remaining sliveris designated 22a or22a' andformsayarnofcorrespondingly reduced thickness which is, however, immediately severed by the severing device 24 controlled by the sensing device 21 via the associated components 33, 36.

In the embodiment shown in Figure 2,two oneway light barriers 37,38 are arranged on a horizontal frame41 which is C-shaped in plan view and which has a slit-likefilament inlet40 and a substantiallyrectangular outline. Each ofthe two light barriers 37,38 has a light emitter42,43 and a light receiver44,45, which are accommodated in suitable bores in the frame41 whichformsacommon housingforthem.

The lenses ofthe light emitters 42,43 and light receivers 44,45 project only slightly beyond the smooth outer periphery of the frame 41, so thatthe frame including the light emitters 42,43 and lightre- ceivers 44,45 accommodated therein has a smooth outer contour on all sides, providing no points of attachmentforthe settling of fly. Consequently the entire sensing device 21 is not prone to soiling and, more particularly, does not have a tendency to pick up fly. Moreover, thanks to its smooth surface, it is easy to clean, either mechanically or by means of a conventional portable blower ofthe kind used for pneumatically cleaning spinning machines.

The light receivers 44,45, which preferably comprise photodiodes, for example, receive the light beams generated by the light emitters 42,43, which may be incandescent lamps, light emitting diodes or the like, in a straight beam path and convertthem into corresponding electric signals.If a remaining sliver, such as 22a or 22a', moves into the light beam of one ofthetwo light barriers 37, 38 as the result of breakage ofthe other sliver, such as 22' or22,the radiation energy received by the corresponding light receiver 44 or45 is reduced and consequently, as explained more fully hereinafter, an electric breakage signal is triggered which causes the severing device 24to severthe remaining sliver22a or22a' which is in the form of yarn and may possibly signal the breakage to an attendant or an automatic resetting carriage in order to remedy the fault.

The light barriers 37,38 may also be constructed as reflection light barriers, i.e. the light emitted bythe light emitter in question is reflected by a reflector in the opposite region of the frame 41 and received by a light receiver arranged beside it. The intensity of light received is reduced accordingly if a single remaining sliver enters the light beam.

The electric signals produced by the light receivers 44,45 may preferably be fed into a threshold detector 33 the threshold of which can be adjusted by means of a threshold selector 34common to all the spinning units ofthe machine in question orallthespinning units ofthe particular longitudinal side ofthe machine, so that the threshold of each threshold det ector33 can be adjusted to thethickness or number ofyarn being spun. Figure 1 shows some additional threshold detectors 33 associated with other spinning units of the spinning machine.

The spinning machine may have, for example, several hundred spinning units. Each threshold detector 33 is constructed so that as long as the output signals ofthe light receivers 44,45 associated therewith exceed the threshold value set, it does not deliveran output signal, but it does deliver an output signal when the output signals fall below the threshold set.

It can be convenient if the movement below the threshold is signalled only if it lasts for a specific short period oftime without interruption, this length oftime being chosen so that it cannot be caused by accidental reflections and vibrations of the yarn 23.

This length of time may also be adjusted using the threshold selector 34. The output signal from the threshold detector 33 forms the breakage signal of the spinning unit in question and is shaped and amplified in an amplifier and pulse forming step 36 and then fed into the yarn severing device 24to init iateacutting operation, so that the remaining yarn 22a or 22a' is cut bythe yarn severing device 24 and in this way spinning oftheyarn is stopped.

Instead of taking the form of light barriers, the two sensors 37,38 may conveniently be of a different construction in many cases, e.g. reflex scanners as shown in Figure 3 in a modified embodiment ofthe sensing device 21. Here, each of the two photosensitive sensors 37', 38' has a light emitter 42,43 and a light receiver 44, 45, which are arranged side by side.

In this embodiment, when one sliver breaks there- maining sliver,22a or22a', enters the light beam of the appropriate emitter 42 or 43 to such a degreethat it reflectsthe beam to the respective receiver 44 or45 which responds to the light reflected to it from the remaining sliverthus detecting the break.

It is also possible to construct the photoelectric sensors in such a way that they have no light emitters, only light receivers which respond to the light of the normal room lighting ofthe machine room when reflected by the remaining sliver 22a or 22a'.

Claims (11)

1. Spinning apparatus comprising a spinning unit, said spinning unit having a drawing mechanism and a twisting mechanism wherein, in use,two textile fibre bundles are drawn from the drawing mechanism as untwisted spaced apart slivers, said slivers converging to a junction point afterwhich they are twisted togetherto form a yarn which runsto the twisting mechanism, said spinning unitfurther comprising a breakdetectorwhich, in the event of breakage of either ofthe two fibre bundles, detects the sideways displacement ofthe remaining fibre bundle running from the drawing mechanism to the twisting mechanism and triggers a breakage signal, said break detector comprising two sensors which scan the two possible paths of the remaining fibre bundle.

2. Apparatus according to claim 1, wherein said break detector comprises a photoelectric sensing device and said sensors scan photoelectrically without making contact with the fibre bundles.

3. Apparatus according to claim 2 wherein said sensors comprise light scanners.

4. Apparatus according to claim 3 wherein said sensors comprise light barriers.

5. Apparatus according to claim 2 wherein said sensors comprise reflex scanners.

6. Apparatus according to any preceding claim, wherein said sensors are arranged on a C-shaped substantially rectangular frame.

7. Apparatus according to any preceding claim, wherein said break detector is associated with a threshold detectordevicewhich emitsa breakage signal in response to changes in the output signals of the sensors of the break detector caused by breakage of a fibre bundle.

8. Apparatus according to claim 7, wherein said threshold detector device only signals breakage of a fibre bundle if the movement above or below the threshold which may be caused by such breakage lasts for a predetermined length of time without interruption.

9. Apparatus according to any preceding claim, whrerin said break detector controls a yarn severing device and/or a slubbing stop device.

10. Spinning apparatus comprising a drawing mechanism and a twisting mechanism, wherein slivers are drawn from the drawing mechanism and converge to a junction point at which the slivers are twisted toform a yarn running to the twisting mech anism, the apparatus further comprising a breakdet ectorintheform of scanning means which in the event of breakage of either sliver is adapted to detect the consequential lateral displacement of the yarn or ofthe remaining unbroken sliver.

11. Spinning apparatussubstantially as herein before described and as illustrated in the accompanying drawings.