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group 8 KNITTING.pptx

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group 8 KNITTING.pptx

  1. 1. COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF TEXTILE ENGINEERING COURSE:KNITTING TECHNOLOGY TWO TITLE:PATTERNING MECHANISM IN WARP AND PATTERN CHAIN NOTATION SUBMITTED TO Dr Kumar SUBMISSION DATE:19/09/2011E.c
  2. 2. Cont… NO NAME ID NUMBER 1 DECHASA DIRO ENG(R)262/09 2 TIGIST YEGILE ENG(R)863/09 3 ASMAMAW TSEGA ENG(R)131/09 4 YISIHAK ABEYA ENG(R)946/09 5 ANDINET WODAJO ENG(R)107/09 6 GOSA KEFENU ENG(R)412/09
  3. 3. PATTERNING MECHANISM IN WARP KNITTING AND PATTERN CHAIN NOTATION INTRODUCTION  A knitting pattern consists of a number of varying lengths of under laps each followed by over lap that wraps the threads over one needle each time.  The main function of the patterning mechanism is to provide the needles with threads at the appropriate points in the knitting cycle following a specified sequence which produce a given knitted pattern.
  4. 4. Cont…  The patterning rings through which the yarns are threaded radially need to be rotated in order to provide the required shogging motion which is the most important function in a warp knitting machine as it determines the machines would produce a given knitted pattern
  5. 5. Cont… The shogging movement is initiated by varying the radius of the continuously turning pattern shaft either in the form of different heights of pattern links which poses over a pattern drum attached to the shaft or in the form of carefully shaped solid metal circular cams, termed pattern wheels, attached to it.
  6. 6. Cont…  An increase in height one link to the next produces a thrust against the end of the guide by shogging it positively into the machine a decrease will produce a negative shog towards the pattern shaft as the result of the action of a return spring.  A constant height will produce no shog if the guide bar will continued to swing through the same needle space.
  7. 7. Cont…  The periphery of the pattern wheel or chain track is scanned by a roller which is link by a flexible jointed push-rod to the end of the guide bar.  The under side of the rod near the roller is supported on the side with moves freely or a metal surface as shogging occurs.
  8. 8. Cont…
  9. 9. Cont…  One known pattern mechanism for such a use includes final control elements which are connected to the guide bars via elongated tension elements.  In this type of pattern mechanism, the stroke of a final control element or the cumulative strokes of a number of final control elements correspond to the shogging motion of the guide bars
  10. 10. Cont…  Further, the stroke or the sum of the strokes correspond to the selected fineness of the needle spacing of the machine.  If the needle spacing of the machine is changed by replacing the needle bar, either the entire final control element system must be changed or the control elements must be adjustable. In the latter case, the control elements must be adjusted individually.
  11. 11. Cont…  However, this is a relatively tedious task.  Further, the speed of the machine will be restricted if the final control elements produce the same stroke as the shogging stroke, particularly if there is a small spacing between the needles.  Accordingly, it is an object of the invention to avoid a complicated positioning and time consuming adjustment in the pattern mechanism for a warp knitting machine
  12. 12. Cont…  It is another object of the invention to obtain a high speed in a warp knitting machine with relatively small needle spacing. Briefly, the invention provides a pattern mechanism for a guide bar of a warp knitting machine which is disposed for reciprocation in a shogging direction
  13. 13. Cont… The pattern mechanism includes a tension element connected at one end to the guide bar, at least one final control element disposed along an opposite end of the tension element for reciprocating the guide bar in the shogging direction and replaceable means for guiding the tension element thereon to change the shogging of the guide bar without changing the final control element
  14. 14. Cont… Briefly, the invention provides a pattern mechanism for a guide bar of a warp knitting machine which is disposed for reciprocation in a shogging direction. The pattern mechanism includes a tension element connected at one end to the guide bar, at least one final control element disposed along an opposite end of the tension element for reciprocating the guide bar in the shogging direction and replaceable means for guiding the tension element thereon to change the shogging of the guide bar without changing the final control element.
  15. 15. Cont… The replaceable means for guiding the tension element may be in the form of a reduction gear which is exchangeable for other reduction gears having different fixed stepped-down ratios. Thus, if the needle spacing is changed, it is only necessary to change the stepped down ratio, for example, by replacing the gear for another having a different fixed ratio.
  16. 16. Cont… Alternatively, the stepped-down ratio can be changed by using change gearing which can be changed stepwise or steplessly. In one embodiment, the reduction gear is constructed as a multi-stepped roller. In this embodiment, the associated tension element has one part connected between one step of the roller and the guide bar and a second part connected to a second step of the roller for cooperation with the final control element.
  17. 17. Cont…  Advantageously, the stepped roller serves as a guide roller for the tension element.  In another embodiment, the reduction gear is formed as a roller having a periphery formed of curved portions with different radii.  In this case, the tension element is guided around the roller with a first part running to and from a first portion of the roller and a second part running to and from a second portion of the roller
  18. 18. Cont... In plan view, the identically y-shaped chain links are similar in appearance to a tuning fork with the fork end leading.  The tail of the preceding link fits into the fork.  The number of links per course is fixed for each machine.  A minimum of two is usually required, with the under occurring between the second link of one course and the first link of the next.
  19. 19. Cont…

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