Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
  • D01G15/00—Carding machines or accessories; Card clothing; Burr-crushing or removing arrangements associated with carding or other preliminary-treatment machines
  • D01G15/02—Carding machines
  • D01G15/12—Details
  • D01G15/46—Doffing or like arrangements for removing fibres from carding elements; Web-dividing apparatus; Condensers
  • D01G15/64—Drafting or twisting apparatus associated with doffing arrangements or with web-dividing apparatus

Definitions

• This invention relates to a carding / drafting leveller system for controlling the production of sliver.
• TG rollers tongue and groove
• One of the measuring rollers is usually mounted in such a way as to allow its axis of rotation to move radially relative to the other roller in response to variation in sliver thickness of the sliver passing between the rollers, and this movement is monitored and provides, where necessary, feedback to vary the speed of the feed roller.
• the sliver issuing from the measuring rollers then usually passes to a coiler. Other times it passes to a drafting system, comprising drafting rollers whose relative speed of rotation is set to provide a required "drafting ratio", which might typically be of the order of 1.3:1.
• the invention is concerned with overall control of the carding and drafting operation in production of a sliver, and seeks to provide improved response of the drafting operation to variation in performance of the measuring rollers.
• a first aspect of the invention provides an apparatus for controlling the formation of a sliver and comprising: a card; a feeding device upstream of the card for feeding a lap to the card ; a condenser downstream of the card to form a sliver; a set of measuring rollers arranged to receive the sliver and to monitor the parameters of the sliver, said rollers being arranged to respond to deviations from a desired value; a feedback control arranged to respond to deviation monitoring by the measuring rollers and to make compensating adjustment in the speed of operation of the feeding device; a drafting system including at least a pair of drafting rollers arranged downstream of the measuring rollers; drive means for driving the drafting rollers at a relative speed to provide a required drafting ratio; a feed-forward control also arranged to respond to deviation monitoring by the measuring rollers and coupled with said drive means so as to provide corresponding variation in speed of the drafting rollers; a device for monitoring the ratio between the peripheral distance travelled by the consecutive rollers of
• this aspect of the invention provides sliver formation apparatus in which there is automatic control over the feeding supply to the card as a result of downstream monitoring of the sliver by the measuring rollers (so-called closed loop levelling), and in addition the transmission of drive to the drafting rollers at a predetermined drafting ratio is subject to two-part feed-forward control, one part of which is responsive to sliver deviation monitoring by the measuring rollers and the other part of which is responsive to relative peripheral distance monitoring by said monitoring device.
• the feedback control (to the feeding device) may take any suitable mechanical or electromechanical form, of a type known per se in "autolevellers" .
• the drive means to the drafting rollers may take any suitable mechanical, electromechanical or electronic form.
• a differential gear drive acts between the measuring rollers and the drafting rollers e.g. providing direct transmission between one roller of each set, and this provides the normal required drafting ratio.
• a further differential gear may be provided, which adds to, or subtracts from the output of the first mentioned differential gear, and which receives two separate control inputs, one of which is supplied by a sliver deviation monitoring signal from the measuring rollers, and the other of which is derived from a deviation signal from the comparator which receives from the monitoring device a signal representative of the ratio between peripheral distance travelled by one of the measuring rollers relative to the peripheral distance travelled by one of the drafting rollers.
• the drafting system comprises a single pair of drafting rollers arranged downstream of the measuring rollers, in which case the monitoring device monitors the ratio between the peripheral distance travelled by the measuring rollers relative to the peripheral distance travelled by the drafting rollers.
• the drafting system comprises consecutive pairs of drafting rollers.
• the invention also includes a novel method of controlling the formation of a sliver using apparatus according to the invention, and preferably with one or more of the preferred aspects thereof.
• apparatus for controlling the formation of a sliver comprising: a card; a feeding device upstream of the card for feeding a lap to the card; a condenser downstream of the card to form a sliver; a set of measuring rollers arranged to received the sliver and to monitor the parameters of the sliver, said rollers being arranged to respond to deviations from a desired value; drafting rollers arranged downstream of the measuring rollers; drive means for driving the drafting rollers so as to provide a required drafting ratio; a feed-forward control also arranged to respond to deviation monitoring by the measuring rollers and coupled with said drive means so as to provide corresponding variation in speed of the drafting rollers; a device for monitoring the average weight of the sliver and comparing with a desired
• Figure 1 is a schematic illustration of a first embodiment of carding / drafting leveller system according to the invention for controlling the production of sliver;
• Figure 2 is a schematic illustration of a control system for controlling the operation of the drafting rollers as a consequence of variation in operating parameters of the system
• FIGS 3 to 6 are schematic illustrations of further embodiments of the invention.
• FIG. 1 of the drawings there is shown schematically a combined carding and drafting system, in which the carding zone and measuring rollers is shown by zone A, and the drafting zone is shown by reference B.
• a carding machine is shown schematically by reference 10, and a feeding device in the form of feed plate 11 and feeding roller 12 provide input of lap to the card in well known manner, and a funnel or trumpet 13 forms part of a condenser downstream of the card 10 to form a sliver.
• a set of measuring rollers 14 and 15 is arranged to receive the sliver, and rotate at a generally pre-set speed, but are provided with monitoring devices which are able to monitor the sliver parameters, and to provide command signals in response to deviation of these parameters from a desired value.
• sliver thickness is monitored, and one of the measuring rollers is able to move radially relative to the other roller as a consequence of fluctuation in sliver thickness, and thereby provide an appropriate position detection signal (PDS - see Figure 2).
• a feedback control (not shown in detail) is provided which responds to deviation monitoring by the measuring rollers 14, 15, and to make compensating adjustment in the speed of operation of the feeding device, which may comprise adjustment in the speed of rotation of feeding roller 12.
• This type of control over the rate of input to the card 10 is well known, and may take any convenient mechanical or electromechanical form.
• the component parts of the zone A which have been described comprise a- standard "closed loop levelling card”.
• the drafting zone B comprises a set of drafting rollers 16 arranged downstream of the measuring rollers 14, 15, and operable to rotate at a predetermined peripheral speed relative to the speed of the measuring rollers 14, 15, to provide a required drafting ratio.
• the zone B comprises an open loop draft leveller, in which sensing is carried out in the measuring rollers 14, 15, and the drafting rollers 16 are capable of being driven at variable speed.
• the zone A produces a precise long term levelled sliver, namely long lengths of sliver having the same weight per yard.
• zone B The average draft carried out in zone B is shown by reference d, and therefore if the sliver weight measured at the measuring rollers (TG rollers) 14, 15 doubles, the draft immediately doubles.
• the periphery of drafting rollers 16 in the long run must travel d times the periphery travelled by the measuring rollers 14, 15. '
• the peripheral distances run by the measuring rollers 14, 15, and the drafting rollers 16 are constantly measured, as will be described in more detail below with reference to Figure 2. If the ratio of the distances run differs from d, then a small increment of base speed is added to, or subtracted from the original speeds of the drafting rollers 16, as commanded by deviations from correct sliver weight as signalled by the measuring rollers 14, 15.
• zone A there is provided a feedback control which responds to deviation monitoring by the measuring rollers when deviation in sliver parameter is measured, and which thereby makes compensating adjustment (after integration) in the speed of operation of the feeding device, in respect of the zone B, there is a two-part feed-forward control which is coupled with the drafting rollers 16 and which detects long term deviation or "drift" from the pre-set speed, and thereby make compensating adjustment in the speed of the drafting rollers 16.
• FIG 2 shows schematically a mechanical coupling between the measuring rollers and the drafting rollers, and this is one preferred way of achieving the necessary control.
• other mechanical, electromechanical, or electronic control systems may be provided if desired.
• measuring roll 14 is movable up and down as shown by the arrows, in response to sliver variation, and an axial position detector APD responds to this movement, and issues a position detector signal PDS to motor M.
• This signal will also be utilised to control the speed of operation of the feeding device 12, after integration as shown schematically.
• a peripheral distance detector shown by reference D1 e.g. a rotational speed monitor
• D2 monitors the distance travelled by one of the drafting rollers 16.
• a differential gear I provides primary drive between the measuring rollers and the drafting rollers and is shown schematically between roller 15 of the set of measuring rollers, and to one of the drafting rollers 16. This drives the -drafting rollers at a predetermined speed to provide a required drafting ratio (say 1.3:1 ). However, there is superimposed on this drive transmission two separate controls via a second differential gear II which is operated by motor M and control motor . This provides input to the differential gear I, to control the output speed transmitted to the drafting rollers 16.
• Sliver parameter monitoring by the measuring rollers 14 and 15 issues position detector signal PDS to the motor M, which drives the differential gear II accordingly, and thereby provides a first part of a feed-forward control to the drive means (first differential gear I) in order to vary the speed of the drafting rollers accordingly.
• Deviation signal DS to motor applies an input to second differential gear II, which provides a further and separate control input to the differential gear I.
• a further set of measuring rollers may be added downstream of the drafting system, and preferably with a trumpet or funnel upstream of the further set of rollers.
• additional rollers preferably tongue and groove rollers
• feed roller levelling will generally still be used.
• Figure 1 of the drawings shown an embodiment in which the drafting zone B is defined between a pair of measuring rollers, 14, 15 and a downstream pair of drafting rollers 16.
• other embodiments of the invention may .have different types of drafting system, in which consecutive pairs of drafting rollers form the drafting system.
• the relative speeds of the consecutive pairs of rollers is controlled by drive means to provide the required drafting ratio.
• sliver passing through measuring rollers 14, 15 is then received by a drafting zone comprising consecutive pairs of drafting rollers 31 and 32, whose relative speeds can be varied to provide a required drafting ratio by suitable drive means. This provides a constant speed tension draft in the zone between upstream drafting rollers 31 and the tongue and groove measuring rollers 14, 15.
• FIG. 4 An alternative arrangement is shown in Figure 4, in which the drafting zone comprises tongue and groove rollers 33, a trumpet 34 downstream of rollers 33, and a second set of tongue and groove rollers 35. Variable speed between pairs of rollers 33 and 35 provides the required drafting ratio.
• Figure 5 shows another embodiment, in which drafting zone B is an "open loop" system. Sliver first passes between tongue and groove rollers 36, and then onwardly to further rollers 37, and a variable speed is set between rollers 36 and 37, and downstream of rollers 37 is a further pair of tongue and groove rollers 38, from which can be derived a signal feeding to control motor m.
• FIG. 6 A still further embodiment is shown in Figure 6, in which the drafting zone B include tongue and groove rollers 36, and downstream thereof two consecutive pairs of vari-speed rollers 39 and 40, followed by trumpet 41 and final tongue and groove rollers 42, also supplying signal to control motor .

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Spinning Or Twisting Of Yarns (AREA)
• Preliminary Treatment Of Fibers (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10738787

Family Applications (1)

Country Status (6)

Cited By (3)

Families Citing this family (1)

Citations (4)

• 1993
  • 1993-07-14 GB GB939314538A patent/GB9314538D0/en active Pending
• 1994
  • 1994-07-13 WO PCT/GB1994/001517 patent/WO1995002720A1/en active IP Right Grant
  • 1994-07-13 JP JP7504409A patent/JPH09502770A/ja active Pending
  • 1994-07-13 EP EP94920560A patent/EP0708849B1/en not_active Expired - Lifetime
  • 1994-07-13 DE DE69417036T patent/DE69417036D1/de not_active Expired - Lifetime
  • 1994-07-14 IN IN559CA1994 patent/IN181817B/en unknown

Patent Citations (4)

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