Patent Description:
Ring spinning machines are the most crucial machines in textile spinning mills. The said ring spinning machines delivers the final stage of cotton in spinning line, so called yarn. During ring spinning, yarn breakage occurs frequently, and it is to be continuously monitored and pieced by the manual labours. The yarn breakage occurs due to various parameters of yarn and machine and it is unavoidable. The broken yarn thread normally tangles with the wound yarn in the cop at any portion from top to bottom of the cop which cannot be adjudged precisely. In long spinning frame sites, manual labours continuously watch for yarn breakages and perform manual piecing of broken yarns. This has to be done for a machine frame normally consisting of more than <NUM> spindles. Then, yarn spinning sequence has to be restarted then and there after yarn breakage in order to resume yarn spinning and to avoid wastage of yarn.

To overcome above problems, automatic piecing units are developed. The automatic piecing unit is in the form of a movable vehicle with wheels/rails. The said piecing vehicle stops at respective spindle units which require piecing attention. The piecing unit in general moves longitudinally over the machine frame aisles. Before initiating piecing operation, the piecing vehicle stops in front of the spindle position of ring spinning machine. Then the broken yarn end which is available in the spinning cop has to be found and detached from the cop and lifted above to enable piecing operation. The said detaching of yarn from spinning cop is not successfully done so far in any known type of automatic piecing units.

<CIT> discloses a yarn lifting arrangement for a yarn piecing unit in a textile ring spinning machine according to the preamble of claim <NUM>.

<CIT> and <CIT> each disclose a yarn lifting arrangement with a plurality of jet members to improve the separation of the yarn end from the cop.

The present invention provides an improved arrangement for detaching the broken yarn end from the spinning cop to enable automatic piecing in ring spinning machines.

These objectives are provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This objective are not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

The main object of the present invention is to provide a yarn lifting arrangement for a yarn piecing unit in a textile ring spinning machines.

The present invention provides a yarn lifting arrangement for a yarn piecing unit in a textile ring spinning machine according to claim <NUM>.

Further, the present invention provides a method for lifting a yarn by a piecing unit according to claim <NUM>.

Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawing, illustrating by way of example the principles of the invention.

For a more detailed understanding of this invention, reference is made to the accompanying drawings in which:.

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, and features.

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. 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 and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness. Automatic piecing unit is provided for textile ring spinning machines. The automatic piecing unit moves longitudinally along the aisle of the ring spinning machine. The ring spinning machine is capable of winding yarn onto a bobbin mounted to spinning spindle, so called cop. When yarn breakage occurs in the spinning sequence, the broken yarn thread is tangled in the spinning cop. To enable yarn piecing, the tangled yarn end has to be detached from the cop. Thus, automatic piecing unit assists in yarn piecing operation during yarn breakage incidents in ring spinning machines. The proper picking / detaching of the broken yarn end from the spinning cop is necessary for the successful piecing of the broken yarn ends. To enable the detaching of the broken yarn end, the present invention is provided with a yarn lifting arrangement in the automatic piecing unit.

<FIG> and <FIG> illustrates the schematic view of the yarn lifting arrangement, according to the present invention. Accordingly, a yarn lifting arrangement (<NUM>) for an automatic yarn piecing unit (<NUM>), comprising of a base plate (<NUM>) having a first end and a second end. The first end connected to an actuating means (<NUM>) provides the base plate (<NUM>) working position in the forward motion and home position in the backward motion. The actuating means (<NUM>) is at least a pneumatic piston - cylinder actuator preferably or the like. The second end is a free end having an opening near to the free end configured to encircle a cop (<NUM>) of a spindle (<NUM>) in the working position. In a preferred embodiment said opening is in semicircular shape. Said yarn lifting arrangement (<NUM>) further comprises plurality of jet members (<NUM>) configured to position around the contour of the opening, supplying air current in the working position to detach the tangled yarn end from the spinning cop (<NUM>) and to lift the yarn upwars towards the drafting zone to enable effective automatic yarn piecing in the textile machine. The corresponding <FIG> illustrates the side view of the yarn lifting arrangement in the automatic piecing unit and winding cop of ring spinning machine in which broken yarn is to be lifted, and <FIG> illustrates broken yarn is lifted and sucked upwards into the top suction unit in front of the drafting zone of the ring spinning machine, according to the present invention.

The jet member (<NUM>) is a block having plurality of orifices (118B) on the tapered surface formed at an acute angle between the top face and the side facing said cop. The air purging hole of the orifices (118B) of the jet members (<NUM>) forms an acute angle with respect to the vertical. According to an embodiment of the invention, the acute angle between the orifice (118B) and the vertical is in the range of <NUM> degrees to <NUM> degrees, preferably <NUM> degrees. The diameter of the orifice (118B) is preferably <NUM>. The block has a through hole (118A) along the horizontal axis parallel to line of position of the plurality of orifices (118B) such that air from a suction source is transferred to plurality of orifices (118B) through hole (118A). The block can also be provided with hole along the horizontal axis perpendicular to line of position of the plurality of orifices (118B). <FIG> illustrates the schematic view of a jet member, and the corresponding <FIG> illustrates the top view and cross-sectional view the of a jet member.

The number of jet members (<NUM>) in a yarn lifting arrangement (<NUM>) is three. The jet members can also be a common unit according to an embodiment. The jet members are positioned on the contour of the opening at an included angle of <NUM> degrees between them. The first jet member (108B) is placed in front of the spinning cop in substantially parallel manner to the length of the ring spinning frame. The second and third jet members (108A, 108C) are placed in substantially perpendicular manner to the length of the ring spinning frame, one each at the sides of the spinning cop. According to the invention, each of the jet members (108A, 108B, 108C) are provided with three orifices (118B).

In the process of yarn lifting, the yarn lifting arrangement (<NUM>) is actuated to move forward to reach working position in which jet members (<NUM>) are positioned concentrically around the cop (<NUM>) of the spindle (<NUM>) in front of the ring rail of ring spinning machine (not shown) slightly below the ring rail position. In the next step, the cop (<NUM>) placed in the ring spinning spindle (<NUM>) is purged with air from the jet members (<NUM>). Thus, the broken yarn (<NUM>) end is lifted from the cop (<NUM>) and caught into the suction unit (<NUM>) which is provided with controlled suction so as to not unwind the already wound cop (<NUM>). Then the detached yarn end (<NUM>) is moved upwards into a controlled suction nozzle adjacent to the drafting unit to hold the yarn until piecing said yarn with the drafted roving material delivering from drafting zone.

According to an example embodiment of the invention, the jet members are worked in the following sequence to achieve successful detaching and lifting of the broken yarn end from the spinning cop. The jet members are positioned at a predetermined distance from spindle centre, along the contour of the opening. When the spindle brake (not shown) is applied for a predetermined period in the range of <NUM> to <NUM> second, for example <NUM> seconds, spindle stops rotating. During that time, the second and third jet members (side jets) are made to purge air jets through the plurality of orifices for a fraction of second in the range of <NUM> to <NUM> seconds, for example <NUM> seconds. Subsequently, spindle brake is relieved for a predetermined period in the range of <NUM> to <NUM> seconds, for example <NUM> seconds, rotating the spindle. During that time, the first jet member is made to purge air jet through the multiple / plurality of orifices for a fraction of second in the range of <NUM> to <NUM> seconds, for example <NUM> seconds. As a result of above said sequences, the broken yarn end is detached from the spinning cop irrespective of its position anywhere from top to bottom and directed upwards towards the drafting zone successfully. The yarn end detached and directed upwards by the action of the jet members are sucked by another controlled suction unit placed at the top of the automatic piecing unit in front of the drafting zone of the ring spinning machine (not shown). Thereby, the broken yarn is lifted to enable automatic piecing with the drafted material.

According to another example embodiment, the jet members are worked in the following sequence to achieve successful detaching and lifting of the broken yarn end from the spinning cop. Initially, the jet members are placed at a predetermined distance from spindle centre along the contour of the opening. The first jet member purges air jet when the spindle is applied brake for a predetermined time interval. Then, the spindle brake is relieved for a predetermined time interval in fraction of second. During that time, the second and third jet members purges air jet. As a result of the above said action, the broken yarn end is detached from the spinning cop and directed upwards to enable automatic piecing with the drafted material. The above sequence takes place irrespective of the ring rail position. The above sequences are example embodiments only. The three jet members are worked in any different sequences and any different time intervals. The jet members are not defined to three in total, it may also be more than three.

Generally, the lifting arrangement is placed in front of the ring rail slightly below the ring rail position such that it purges air towards the cop from plurality of orifices for lifting the broken yarn end from the cop. The lifting arrangement can be advantageously placed at any position in front of the cop from top to bottom as an embodiment. In a preferred embodiment, the lifting arrangement is positioned at the bottom portion of the spinning cop. Thus, the above described automatic piecing unit for ring spinning machine frame provides an effective broken yarn end lifting arrangement.

Claim 1:
A yarn lifting arrangement (<NUM>) for a yarn piecing unit (<NUM>) in a textile ring spinning machine, comprising:
a control unit for controlling the manner of how air is injected towards a cop (<NUM>), a base plate (<NUM>) having a first end and a second end,
said first end connected to an actuating means (<NUM>) which provides said base plate (<NUM>) a working position in the forward motion and a home position in the backward motion,
said second end is a free end having an opening near to the free end configured to encircle the cop (<NUM>) of a spindle (<NUM>) in working position; characterized in that, the plate base (<NUM>) comprises further a first jet member (108A), a second jet member (108B) and a third jet member (108C), each provided with three orifices (118B), configured to position around the contour of the opening, supplying air current to said first, second and third jet members (108A, 108B, 108C) to purge air jets through the plurality of orifices (118B), when the base plate (<NUM>) is in working position to detach the tangled yarn end (<NUM>) from the spinning cop (<NUM>) and to lift the yarn upwards to enable yarn piecing in the textile ring spinning machine and wherein all of the three jet members (108A, 108B, 108C) are at equal distance from the cop (<NUM>) and all the three jet members (108A, 108B, 108C) are provided with air current in different sequences and different time intervals.