FIELD OF THE INVENTION

The present invention relates to an improved lap winding apparatus for a textile spinning preparatory machine. Particularly this invention relates to the Loading system of lap formation on a textile machine, more particularly Lap winding rollers of a lap forming machine for the Combing operation.

BACKGROUND OF THE INVENTION

Combing is an important value addition process in textile yarn manufacturing. Combing is carried out in two stages; the first stage of preparing a package of a compact sheet of textile fibres wound in long lengths on a spool, the package is called a Lap. The second stage is of the proper combing where the compact sheet of textile fibre from the Lap is fed to the Combing machine by unwinding the lap

The preparation of the lap itself can be in a single stage or multiple stages and the machine is called a Lap Former/ lap-forming machine

A Lap Former / lap forming machine consists of feed creel, drafting zones, doubling table, compacting calendar rollers and finally Lap rollers for winding the material onto the spool.

This Lap is required to have certain physical quality parameters to enable it to perform better in subsequent stage. These parameters include uniform linear density and compactness of the material sheet and its winding in the package.

The recent development in the field of engineering and technology has led to a very substantial increase in the speeds of lap formation and the content of the lap in the form of longer length and heavier lap sheet. These increase in the winding speed, lap weight. Further the automation of lap doffing and their transport and replenishment on the combing machines have all led to increased strain on the Lap.

This increased strain has resulted in the increased incidences of Lap defects such as un-even compactness, damages to lap spool, licking of inter layer lap sheet, soft and bulky Laps, and etc. in the Laps produced by high speed and bigger package Lap formers.

Various corrective steps were initiated through research to minimise the effect of above problems. Most of the research conducted and the prior art available are related to:

- using different methods of calendaring and nipping loads for compacting the material sheet over its length

- using different tension drafts prior to lap winding

- using variable Load during the Lap build.

- using various combination of plain surface and flutes surface lap rollers

The above efforts have given some marginal improvements over the problems but did not fulfill the required level.

Hence the attempt to control the load across the width of the lap during its build has given the desired result of better compactness and safety from spool damages.

OBJECTS OF THE INVENTION

The object of the present invention is to provide an improved spool and lap winding rollers, which provides an improved compactness of the Lap sheet across its width.

Another object of the present invention is to provide a lap forming apparatus which provides a lap roll for proper unwinding of the Lap sheet during feed to Combing machine.

Yet another object of the present invention is to make a lap with compact edges of the full Lap to avoid wastage during handling.

One more object of the present invention is to provide an improved lap winding apparatus which gives protection of lap spool from damages.

Furthermore object of the present invention is to provide an improved lap winding apparatus that reduces the intensity of fibre migration of a lap roll.

SUMMARY OF THE INVENTION

The research is made to control the load across the width of the lap. The invention of changing the shape of the winding lap rollers from that of a cylinder to a barrel by providing taper at the edges has addressed the problem of load variation across the width of the lap at the initial stage of winding and therefore has given desired result of compactness. These tapers, the change of ratio between the length and diameter of the roller can be in one set or combination of multi tapers on either end of the lap rollers or spool.

According to one aspect of the present invention there is provided a lap winding apparatus for lap forming machine comprises means for winding lap on spool, means for providing compactness of winding during lap formation wherein atleast one end of the lap roller and/ or spool is substantially tapered.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig-1 represents the isometric view of Lay out of the Lap forming machine.

Fig-2 is the schematic illustration of Lap winding arrangement according to the known art.

Fig-3 is the schematic illustration of Lap winding arrangement and Lap rollers according to the present invention.

Fig-4 of the drawings illustrates the various possible embodiments of the lap roller and spool according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figure 1 and 2, a Lap former/ lap forming machine essentially has its functional areas like feeding, drafting, doubling, compacting or calendaring and package winding. The machine consists of the required drives, suction, controls and monitors.

The feed material in the form of coiled sliver stored in the multiple of cans (1) is drawn through the creel (2) and drafted in the drafting zone (3) to get a combined sliver sheet. A multiple of such drafted sliver sheets are doubled through table calendar rollers (4) and passed through a set of calendar rollers (5) to compact the same. It is then wrapped around a spool (6), which is driven by friction, by a pair of positively driven Lap rollers (7). The winding continues till a predetermined length of Lap sheet is wound onto the Lap (8).

The known lap winding arrangement is shown in Fig-2, wherein usually a pair of Lap rollers (7) is employed to wind the lap sheet onto the spool (6). These are positively driven. The surface of one of the rollers (7) is plain and that of the other is fluted or both the rollers are fluted or plain. Generally the spool (6) is non-metallic and made of synthetic material to withstand its robust use. The surface is neither too smooth to be slippery nor too rough to be sticky. The latest spool has holes or perforations on its surface to enable air suction to assist wrapping of initial layers of the lap sheet at the start of the fresh lap.

Both the lap rollers (7) and the spool (6) are substantially of cylindrical shape. A load is necessarily applied at both the ends of the spool (6) during the lap winding to enable the spool to rotate by the rotating lap rollers (7) due to frictional force.

The increase in delivery speed and the increase in the thickness of the lap sheet necessitated the increase in the load of the spool against the Lap rollers. But this led the spool (6) to buckle under this pressure in the initial stage of lap build when there are no much layers of textile material over the spool surface. The load is lower at the middle portion of the spool length compared to the end portions. This caused damages to the spool ends and also disturbed the winding of slivers in the middle portion of the spool.

A research is made to overcome this problem by providing a substantial taper end on the cylindrical surface of the Lap rollers or spools.

Referring to Figure 3 and 4, the present invention provides a facility to control the nipping load along its length, at the start of winding a fresh lap, between the Lap Spool (6) and its driving pair of Lap rollers (7). This is facilitated by the provision of taper (9 or 9') at the end of the Lap rollers (7) and/or Spool (6). With the help of this arrangement, the nipping load line changes from a straight line to a line combination of multiple slope thereby adjusting the load as per exact requirement at the contact line between spool and lap roller. The another embodiment of the present invention is also shown in Fig-4, wherein the plurality of adjacent taper (10, 10') has been provided at the ends of lap roller (7) and/or spool (6). The position of the taper may extend upto one-third length from the ends towards the centre of the spool (6) and/or lap rollers (7) with single and/or multiple slope.

This invention can be extended for optimizing the effectiveness of the variable load by providing the taper in reverse proportion of the ratio, that is instead of reducing the diameter at the edges or the end, it can be increased but with a different combination for Lap spool (6) and/or winding drums (7). On the other hand the surface length of the drums (7) or the spool (6) in full or part can be matched to a continuous curve. And also, the edges of lap roller (7) and spool (6) can be provided with an arc shape instead of taper as one more variant of the present invention.

The embodiments shown herein are only exemplary. Further embodiments are possible within the scope of the invention.

The invention has been described in detail with respect to preferred embodiment and it will be apparent from the forgoing to those skilled in the art that any changes and modification may be made without departing from the invention in its broader aspects, The invention is therefore intended to cover all such changes and modifications that fall within the scope and spirit of the invention.

WE CLAIM:

1) Lap winding apparatus for lap forming machine comprising means for winding lap on spool, means for providing compactness of winding during lap formation

wherein atleast one end of the lap roller and/ or spool is substantially tapered

2) Lap winding apparatus as claimed in claim 1 wherein both ends of the lap roller and / or spool are tapered on outer cylindrical surface

3) Lap winding apparatus as claimed in claim 1 wherein a plurality of taper adjacent to each other is provided at both ends of lap roller and/or spool

4) Lap winding apparatus as claimed in claim 1 wherein taper is extended maximum upto one third of length of cylindrical surface from each end of lap roller and/or spool

5) Lap winding apparatus as claimed in preceding claims wherein taper is extended in single or multiple stages

6) Lap winding apparatus as claimed in claim 1 wherein taper is extended in reverse proportion of ratio by increasing diameter at each end of lap and/or spool with corresponding reduction of diameter at both ends of lap and/or spool

7) Lap winding apparatus as claimed in claim 1 and 5 wherein ends of lap roller and/ or spool are so arranged to provide a continuous curve along contact surface of lap roller and/or spool either fully or partly.

8) Lap winding apparatus as claimed in claims 1 to 7 wherein the ends of lap roller and/ or spool are arc shaped.

9) Lap winding apparatus for lap forming machine as herein described' substantially with reference to accompanying drawing.