DESC:FIELD OF INVENTION
The present invention relates to sliver severing apparatus in textile spinning preparatory machines. More particularly the invention relates to an apparatus for cutting the sliver in a drawing machine, comber, card or the like.

BACKGROUND OF THE INVENTION
Generally the spinning preparatory machine such as sliver drawing machine has an object of doubling and drafting the plurality of fed slivers and to provide the specific dense of sliver in delivery.

A creel arrangement is provided in the feeding zone for feeding plurality of slivers from the plurality of sliver cans into the drafting zone of the drawing machine. In drafting zone, a drafting arrangement is arranged downstream of the feeding zone and the material supplied in the form of slivers are processed by the drafting arrangement and delivered in the form of single sliver, then the said sliver is deposited into the delivery sliver cans arranged underneath a coiling head.

When the delivery sliver can is filled with the drafted sliver, it has to be replaced by empty sliver can, and this process is known as doffing. Before doffing, a thin place must be created in the sliver which is required for severing the continuous sliver without any difficulty and preventing sliver damage (like sliver pulling off or variation in draft in that particular stretching length), to make the sliver can doffing easier and reliable.

As disclosed in DE19548232A1, a device is known in which a thin place is generated in the sliver by increasing the speed delay between the delivery and middle drafting rollers in the main drafting zone. The sliver with the thin place is then conveyed by the calender rollers through the coiler funnel until the thin place reaches the exit opening of the coiler bottom plate. At this moment, the machine is stopped or the delivery speed is reduced to discharge the filled sliver can so that the sliver ruptures at the said thin place. A disadvantage of this device is, this can only work reliably if the middle drafting roller pairs and the delivery drafting roller pairs are driven by an individual motor drives, which is expensive, heavier and complicated construction. Though one disadvantage is discussed here, it is to be noted that there can be several other disadvantages of the cited prior art document which are not discussed herein. A person skilled in the art could easily realize such disadvantages of the prior art.

In another known arrangement, a sliver cutting knife arrangement is provided below the coiler. Said knife grips and holds the sliver while doffing operation takes place and ruptures the sliver while the filled can moves from coiling position. A disadvantage of this device is, a pair of pneumatic cylinders are required for holding arrangement and knife movement. Based on the can size, the stroke of pneumatic cylinder will be ranging from 400mm to 1m, which reflects in increasing the product cost. There is also a certain amount of drafting imparted in the sliver which affects the quality of sliver. Moreover, the emplacement of holding / knife arrangement is difficult when employing in a linear can changer type of doffing. There has thus been a need to develop a new apparatus for severing the sliver that would overcome the disadvantages present in the existing textile machines.

OBJECTS OF THE INVENTION
The object of the present invention is to provide an apparatus for generating a thin place at a specified location of the fibre sliver in a textile spinning preparatory machine.

Yet another object of the present invention is to provide an apparatus for preparing the sliver cutting which aids in reduction of product cost and increased production rate

SUMMARY OF THE INVENTION
The following disclosure presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

According to an aspect of the present invention, there is provided a textile spinning preparatory machine having a drawing unit comprising a drafting zone where fibre sliver is drafted between plurality of top and bottom rollers; said plurality of rollers being arranged as back roller pairs, middle roller pairs and delivery roller set for drafting the sliver wherein a plunging arrangement is provided in the drafting zone for severing the sliver. In the drafting arrangement the fibre sliver are fed for drafting between plurality of top and bottom rollers; said rollers are arranged as back roller pairs, middle roller pairs and delivery roller set for drafting the sliver wherein at least a plunging arrangement is provided in said drafting zone. Before doffing process takes place, the drawing machine comes in to stop position and the top drafting rollers are maintained in the loading position. The plunging arrangement comprises a loading bar which is plunged onto the fleece of fibres in the drafting zone for a predetermined stroke length and then retracted to its home position. This plunging action induces a draft in the said fleece of fibres and generates a thin place in the plunged area. After completing the plunging action, the machine is made run at slow or in normal speed, until the generated thin place reaches the exit opening of the coiler funnel. Now the machine is again stopped and the doffing action takes place. Due to presence of this thin place, the rupturing of the sliver is occurred when the filled delivery sliver can moves away from the coiler head.

Other salient features and advantages of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

Figure-1 represents the schematic illustration of the drafting arrangement in the textile drawing machine according to the present invention.

Figure-2 represents the schematic illustration of the plunging arrangement provided in the drafting zone according to the invention.

Figure-3 shows the exhaustive view of the plunging arrangement according to the present invention.

Figure-4 Shows the pneumatic circuit for the actuating the plunging arrangement according to the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It is to be understood that the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or component but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The drafting arrangement (1) with plurality of drafting zones (3, 4) of the textile drawing machine is shown in Figure-1, where the fed fibre sliver/fleece (S) from feeding zone (2) is drafted between plurality of top and bottom rollers (5-5’, 6-6’, 7-7’). These rollers are mounted in such a way to form the back roller pairs (5, 5’), middle roller pairs (6, 6’) and delivery roller set (7, 7’, 8). In order to even out and/or tension compact the fibre fleece (S), at least a presser bar (P) is provided in the drafting zone (4). The draft applied in the drafting zone (3) is known as break draft and whereas the draft applied in the drafting zone (4) is known as main draft. At least a plunging arrangement (9) is provided in said drafting arrangement (1) for creating a thin place in the fleece (S). Said plunging arrangement (9) is provided in the break draft zone (3) according to the present embodiment whereas the presser bar (P) is provided in the main draft zone (4).

The fibre fleece (S) from the creel (not shown) is drafted and then passed through pair of calender rollers, sliver coiling unit and then supplied into the rotating delivery sliver can in which the condensed fibre sliver (S) is coiled and stored. After a predetermined amount of sliver is filled in the sliver can, the doffing action takes place. Before doffing action is initiated, a thin place is generated in the fibre fleece (S) by the plunging arrangement (9) which is placed in the break draft zone (3) of the drafting i.e., between back roller pairs (5, 5’) and the middle roller pairs (6,6’).

During this process, the drawing machine comes in to stop position and the top drafting rollers are maintained in the loading state.The plunging arrangement (9) comprises a plunge bar (10) as shown in Figure-2 which pushes the fleece of fibres (S) in the break draft zone (3) for a predetermined stroke length and then it retracts to its home position. Thus the fleece held up between the back roller pairs (5,5’) and middle roller pairs (6,6’) receives an localized induced draft by the plunge bar (10) and a thin place or weak point is created thereon. Said plunging arrangement (9) in the drafting zone, is operated by mechanical or pneumatic or electrical or combination of these mechanisms. As further preferred embodiment of the invention, this plunging arrangement (9) can be provided in the main draft zone (4) of the drafting arrangement, so that the thin place is created between middle roller pairs (6,6’) and delivery roller set (7,7’,8). After the thin place is generated, the machine is made to run at slow/normal speed such that the generated thin place is carried to calender rollers and then to the exit opening of the coiler funnel (not shown in drawings). Now the machine is stopped or run at slow speed and the doffing action is initiated. Due to presents of thin place in the condensed fibre sliver, the rupturing of the sliver is occurred due to the stretch while the filled delivery sliver can moves away from the coiler head.

In a further possible embodiment (not shown), presser bar (P) which is used for controlling floating fibers in the main draft zone (4) may also be used to generate thin place in the fibre strand by varying the loading pressure on the said presser bar (P). This kind of presser bar in the main draft zone may also be used in break draft zone (3) alternatively to generate thin place in the fibre sliver (S).

Figure-3 of the drawings illustrates exhaustive view of the plunging arrangement (9) according to the present invention, in which the fibre fleece (5) is held in the break draft zone (3) wherein various stages of the plunging action by the plunging arrangement (9) are shown. Since the depth of plunging influences the thin place intensity, the stroke length (L1, L2, L3) of plunge bar (10) is selected accordingly. When the plunge bar (10) extends to first stroke length (L1), the thin place will be almost nil as the tip of plunge bar (10) just touches the upper surface of the flibre fleece (5). Depending upon the type of fibre and sliver hank value, the depth of intermediate stroke length (L2) and final stroke length (L3) will be decided. When the plunge bar (10) moves down, the intermediate stroke length (L2) and final stroke length (L3) creates an elongated stretches (T1) & (T2) over fibre fleece present on both sides of the the plunge bar (10) and thus weakens the fibre to fibre cohesiveness. Therefore an extreme weak point or thin place is created at the mid portion of said elongated stretches (T1) & (T2). When said mid portion reaches the exit opening of the coiler, the machine is operated for doffing function and rupturing of the sliver takes place therein while the filled sliver can moves away from the coiling head.

Figure-4 represents the schematic illustration of pneumatic circuit of the plunging arrangement according to the present invention, comprising a solenoid valve for actuating said plunging arrangement (10) wherein the timing for plunge bar activation and depth of stroke length (L3) is controlled by programme logic depending upon the requirement. The operation of plunging arrangement (10) can be alternatively operated by mechanical or electrical or both in combination with pneumatic mechanisms.

It is to be understood that the aspects and embodiment of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiment may be combined together to form a further embodiment of the disclosure.
,CLAIMS:1. A textile spinning preparatory machine having a drawing unit comprising a drafting zone where fibre sliver is drafted between plurality of top and bottom rollers; said plurality of rollers being arranged as back roller pairs, middle roller pairs and delivery roller set for drafting the sliver wherein a plunging arrangement is provided in the drafting zone for severing the sliver.

2. The textile spinning preparatory machine as claimed in claim 1,wherein said plunging arrangement comprising a loading or plunge bar adapted to be plunged onto the fleece of fibres in the drafting zone for a predetermined stroke length and then retracted to its home positions such that the plunging action induces a draft in the said fleece of fibres and generates a thin place in the plunged area.

3. The textile spinning preparatory machine as claimed in claim 2 comprising a solenoid valve for actuating the apparatus wherein the timing for plunge bar activation and depth of stroke length is controlled by programme logic depending upon the requirement.

4. The textile spinning preparatory machine as claimed in claim 2 is operated mechanically or electrically or both in combination with pneumatic mechanisms.

5. The textile spinning preparatory machine as claimed in claim 2 wherein the fibre fleece is held in the break draft zone.

6. The textile spinning preparatory machine as claimed in claim 2 wherein the loading or the plunge bar is adapted for plunging at different depth of stroke lengths thereby influencing the thin place intensity.

7. The textile spinning preparatory machine as claimed in claim 6 wherein the plunge bar having three stroke lengths L1, L2 and L3.

8. The textile spinning preparatory machine as claimed in claims 6 and 7 wherein when the plunge bar extends to first stroke length (L1), the thin place is almost nil as the tip of plunge bar just touches the upper surface of the fibre fleece.

9. The textile spinning preparatory machine as claimed in claims 6 and 7 wherein when the plunge bar moves down to the intermediate stroke length (L2) or the final stroke length (L3) creates an elongated stretches (T1) or (T2) in the fibre fleece thus weakening the fibre to fibre cohesiveness.