Saturday, 31 October 2009

Pile Sinker Warp Knitting Tricot Machine

The pile sinker bar on tricot machines is positioned above the compound sinker bar and performs a lateral displacement. The pile threads are lapped over the pile sinkers according to the relevant lapping and are then formed to pile loops.
The distance between the pile sinkers and the compound sinkers can be changed,this means that the pile height can be adjusted.The knitting element of warp knitting tricot machine with sinker pile  showing on the Fig.01

1. Compound needle bar. 2. Guide bar. 3. Pile sinker bar. 4. Sinker bar. 5. Tongue bar (closing element bar,pusher lead) bar.
They are three differences between tricot machine with pile sinker bar and standard tricot machine:
  1. A special pile sinker (No.3) mounted on special sinker bar placed above and lateral with the usual sinker bar (No.4).
  2. The shape of the pile sinker modified and the sinker neb is omitted since the fabric can be held down by the pile sinker.By eliminating the neb of the sinker,the pile sinker can be placed lower and allow more space for guide bars to swing in.
  3. The pile sinker bar is mounted in bracket similar to guider bars bracket .The bracket of pile sinker bar do not swing as like as guide bar bracket but move freely laterally.
Horizontal shogging movement of pile sinker bar is generated by pattern disk .The knitting sequence of the machine is exactly the same as for any standard tricot machine and the loop pile is formed as result of the unique lapping movement.  
Lapping Movements of Pile Sinker Bar
Two different lapping movements are required to produce the ground structure and the pile loops.The ground lapping movement must correspond to the lateral movement of the pile sinker bar and both are shogged in the same direction and at the same magnitude.By always keeping the ground yarn between the same two pile sinkers,it does not cross over the sinker while shogging the under lap and forms no pile loops.
A simple ground construction is illustrated in Fig.2 (1) with the straight lines marking the position of one pile sinker during each and every knitted course.The pile sinker can only move laterally during the under lap period,when the needles are in the knock over (lowest) position.
The chain notations for the ground bar are: 1-2/ 1-0 // and the chain notation for pile sinker bar shogging movement are : 1-1 / 0-0 //.
A more complicated ground construction can be produced by two ground guide bars,as Fig. 2(2).One of the ground guide bars follows the sinker bar shogging movement,whilst the other bar laps the same needles every second course.The yarns of this second ground bar are deflected by the sinker bar,but since overlapping movement take place every second course,the yarns do not cress over the pile sinkers and do not form a pile.
The two ground bars,one of which is chaining,produce a much more stable construction than the one previous described.The chain notations for the second ground construction are:
  • 1-0 / 2-1 / 2-3 / 1-2 // for the back ground bar.
  • 0-0 / 0-1 / 1-1 / 1-0 // for the front guide bar.
  • 0-0 / 1-1 / 2-2 / 1-1 // for the pile sinker bar.
The fully threaded guide bar in the front displacement line used to produce the pile loops on the technical back of the fabric.The lapping movement applied to this guide bar causes its t-yarns to cross from needle to needle,above the pile sinker and when they are pulled into knock over position,they from pile loops over the edge of these pile sinkers (Fig.3).Since the pile sinker bar is shogged every knitted course,the lapping movement of the pile forming front guide bar can simply be a continues chaining motion.For pattering purpose it is possible,however to produce a more complicated movement and to use coloured yarns.