FIELD OF THE INVENTION

The present invention relates to a controlling method of machine restarting sequence of a textile ring spinning machine.

More particularly it relates to a control method defined to eliminate snarls formed during machine stoppage for doffing and establishing a fresh restart with minimum end breaks in a textile ring spinning machine.

BACKGROUND OF THE INVENTION

Ring spinning or twisting machine comprises plurality of spindles uniformly spaced along the longitudinal extent along both sides of the machine. The spindles individually supports the conical tubes for building of yarn named as yarn package. The yarn delivered from the drafting zone are passed via number of components such as lappet, balloon control rings, ring / traveller, and finally yarn wound over the conical tubes placed on spindles. Soon after the built up of predetermined length of yarn, the full yarn packages referred as cops are to be exchanged with empty conical tubes. The exchanging process may be carried by manual or auto doffers.

Particularly during machine stoppages for doffing and donning purpose, the ring rail, balloon control ring rail and lappet guide rail move to the rest position. The lappet guide or the lappet mounted on the lappet rail has to be tilted backward to permit the removal of the cops easily as well as to load the empty conical tube on to the spindle.

In the above situation, the resultant yarn is being suspended without any stretch between the front drafting roller nip to underwinding zone. Due to the distortion in the predetermined amount of twist in the freely suspended resultant yarn which causes formation of snarls along the length of it. During restarting the snarls results in end breaks unless removed properly.

To overcome the above problem, essential characteristic of controlling function is being added in the machine restarting program. In the existing system, the controlling function includes the drive of spindles and subsequently doing snarl elimination.

In this practice, normally the end breakage rate is around 2% - 4%. But when considering the long frames with more than 1500 spindleage capacity, this estimated figure strongly influencing on the performance characteristic of the ring spinning and twisting machine.

Hence it is essential to avoid or reduce the end breaks during machine restarting. And this invention of controlling method of machine restarting sequence in a textile ring spinning and twisting machine would be more useful to resolve the above said problems, assuring for the trouble free operation and productivity of the machine.

OBJECTS OF THE INVENTION

It is an object of the invention to provide an improved controlling method of machine restarting sequence of a textile ring spinning and twisting machine.

It is one of an object of the invention to provide a suitable algorithm for machine restarting sequence of a textile ring spinning and twisting machine.

It is an another object of the invention to provide an algorithm for proper removal of snarls and stable restarting with minimum end breaks in textile ring spinning and twisting machine.

Yet another object of the invention to provide an improved controlling method for machine restarting and obtaining performance improvement in all practical aspects of a textile ring spinning and twisting machine.

SUMMARY OF INVENTION

In the existing system, when ON push button is pressed after doffing sequence, Ring rail moves up to set Special restart position and the Spindle starts winding at this position for the set time (ST). Once the set special restart time is elapsed the ring rail moves up to LONG SNARL UP POSITION (LU) at set speed (LUSPD) and then again moves down to Long Snarl Down position (LD) at set down speed (LDSPD). After Long snarl sequence the ring rail movement is as per Chase and other process settings.

On analysing the operations of the existing method, during the stoppages of doffing and donning process, there are significant number of ends being present with snarls. As the rotation of the spindles are being started before the elimination snarl which resulting for higher end breakages.

According to the solution by the invention, when ON push button is pressed after doffing sequence,
Ringrail moves up to set LONG SNARL UP POSITION (LU) at set speed (LUSPD) and then again moves down to Motor Restart Position (MS) at set Long Snarl Down speed (LDSPD) and Ring rail stops at this position until spindle starts and speed reaches 500 rpm. Once speed reaches 500 rpm the ring rail moves down to Long Snarl Down speed position (LD) at set Long Snarl Down speed 2 (LSSPD2) and from there to Winding start position and follows the chase as per the process settings

Then the machine operations such as spindle drive, speed, ring rail up and down traverse, etc., are being processed as per normal cycle upto the full cop stage. The practical studies conducted with the above improved method of machine restarting program surprisingly resulting in restarting breaks consistently less than 0.5% as against 2 to 4%.

BRIEF DESCRIPTION OF THE DRAWING

Figure 1 illustrates the operational diagram of method of restarting program provided in the prior art.

Figure 2 illustrates the operational diagram of method of machine restarting program provided according to the invention.

BRIEF DESCRIPTION OF THE INVENTION

Now days ring spinning and twisting machines are provided with PLC controlled system to control the activities of an application. The control unit is provided with set of instructions called as algorithm which is used to manage various activities of the ring spinning and twisting machine in a systematic manner. The existing machine restarting program includes the basic activities of the machine application, measuring / controlling factors, set of instructions, action regulations, etc., have been formulated and provided as a feature of PLC controlled system. In a typical ring spinning and twisting machine, the snarl formation is a very common problem happening particularly during machine stoppages of doffing and donning process. In the above situation, the resultant yarn is being suspended without any stretch between the front drafting roller nip to underwinding zone. Due to the distortion in the predetermined amount of twist in the freely suspended resultant yarn which causes formation of snarls along the length of it. During every time of machine restarting the snarls results in an end break unless removed properly and strongly affecting the performance of ring spinning and twisting machine. So it is essential to eliminate the snarls properly.

Referring to figure 1, existing control system is explained. After completion of doffing and donning operations, usually the ring rail is at the underwinding position (51). As a part of snarl elimination and restarting functions, the ring rail is raised upwards from the under winding position (51), crosses the zero position (52) at a desired speed referred as special restart speed (57) and reaches the special restart position (53). Once it reaches the special restart position (53), the ring rail stays there for a certain time, the main motor starts driving the spindles. After reaching the predetermined spindle speed (may be in the range of 0 -1000 rpm, preferably 500 rpm), the spindles are allowed to follow the speed pattern (61) and the ring rail is raised upwards from special restart position (53) upto upper most position (54) at a speed referred as long snarl upward speed (58). Once it reaches the upper most position (54), the ring rail starts lowering at a speed of long snarl downward speed (59) upto a position referred as long snarl downward position (55). After reaching the position (55), the ring rail is further lowered upto the winding start position (56) and normal cop building sequence starts.

Then the machine operations such as spindle drive, speed, ring rail up and down traverse, etc., are being proceeded as per normal cycle upto the full cop stage.

In the above known art, irrespective of various factors count, raw material, machine model, restarting program, the end breaks rate is around 2% - 4%. To enhance the performance of the textile ring spinning and twisting machine

further, this new improved method of controlling the machine restarting sequence of a textile ring spinning and twisting machine is being provided in this invention.

According to the present invention, provided a new and improved controlling method of machine restarting sequence for a textile ring spinning and twisting machine as shown in figure 2. By referring the figure 2, after completion of doffing and donning operations, usually the ring rail is at the underwinding position (101).

The ring rail is raised upwards from the underwinding position (101) and crosses the zero position (102) at a desired speed referred as long snarl upward speed (107) upto the upper most position (103). Once the ring rail reaches the upper most position (103), it starts lowering downwards at a speed of long snarl downward speed (108). Then ring rail is stopped at a preset point referred as motor restart position (104) Spindle is started at this point. When the spindle speed reaches a preset limit may be 500 rpm, again the ring rail is moved down towards the long snarl downward position (105) at a desired speed of long sna,rl downward speed (109). After reaching the position (105), the ring rail is further lowered upto the winding start position (106) and normal cop building sequence starts ie the ring rail and spindles are allowed to run as per the speed pattern (110) defined by user.

With this methodology irrespective of machine load the starting position of the spindle is defined thereby sufficient tension is maintained in the yarn so that restarting breaks are reduced. The practical studies conducted with the above improved method of machine restarting program surprisingly resulting in restarting breaks consistently less than 0.5% as against 2 to 4%.

We Claim

1. An improved controlling method of machine restarting operation of a textile ring spinning and twisting machine comprising raising the ring rail from the underwinding position (101) to the upper position (103), lowering downwards to a down position (105) for normal cop building sequence wherein the ring rail is stopped between position (103) and (105) at a preset point (104) for starting the rotation of the spindle and the downward movement of the ring rail is resumed after the spindle speed reaches a preset limit.

2. An improved controlling method of machine restarting operation of a textile Ring spinning and twisting machine as claimed in Claim 1 wherein the ring rail is raised upwards from the underwinding position (101) and crosses the zero position (102) at a desired speed (107) upto the upper most position (103), the ring rail starts lowering downwards at a desired speed (108), stopped at a preset point (104), Spindle is started at this point, when the spindle speed reaches a preset limit, again the ring rail is moved towards downward position (105) at a desired speed (109), the ring rail is further lowered upto the winding start position (106) and normal cop building sequence starts.

3. An improved controlling method of machine restarting operation of a textile Ring spinning and twisting machine as claimed in Claim 1 and 2 wherein the preset limit of the spindle speed is in the range of 0 -1000 rpm.