The various steps of the stitch formation for the manufacturing of rib knitted cloth are shown inPicture 1.The following description refers to the work carried out by a single needle, however, thecarriage activates the needles of both needle-beds.
Picture 1 - The stitch formationA. The needles are in the knock-over position; the loop threads are inside the hook and thelatches are closed.
B. The carriage moves forward and the cam touches the needle butt. The forward motion of the cam with the tucking cam completely out, forces the needle to move upward; the thread inside the hook opens the latch. Once the needle has reached the tucking plane, the latch is completely open and the loop is laid on it.
C. The forward motion of the carriage makes the needle move upward again, since the loopingcam of the cam is completely out. The needle reaches the maximum height on the looping plane and the stitch is transferred from the open latch to the needle stem. This sudden motion can cause a backstroke, that is a reaction of the latch, which could accidentally close with a possible unsuccessful feeding of the new thread and a consequent knock-over failure. This would lead to the formation of a hole or the starting of a run in the fabric. In order to avoid this, the brushes ensure that the latch opens.
D. Once the maximum height has been reached, the needle is lowered, driven by the loweringcam; after reaching the tucking plane, the thread guide starts working, feeding the thread;the loop rises slightly on the stem and enters the space between the stem and the open latch.
E. The needle continues its downward stroke; the loop touches the latch and makes it rotateand close.
F. The needle reaches the bottom, i.e. the knock-over plane; the previous stitch, after closingcompletely the latch, knocks over on the new thread, forcing it to take up the typicalcurvilinear shape.
Tuck Stitch Formation
Two consecutive strokes of the carriage are necessary to form the tuck stitch (picture 2).
Picture 2 – Tuck stitch formation
During the first stroke, the tucking cam of the cam is out and the looping cam is not working.Therefore the needle only raises as high as the tucking plane; the loop cannot slip on the stem,and therefore remains inside the hook after having completely opened the latch, in this wayallowing the yarn to be fed.During the second stroke both the tucking cam and the looping cam are activated; the needlerises up to the maximum height allowing the loop and the yarn to travel along the stem.Thereafter, the needle is fed with the thread for the second time; the loop and the first yarn closethe latch and knock over on the new yarn.The first yarn does not knock over as a knit stitch but takes a particular position, and fixes ontop of the previous knit stitch and at the bottom of the new one, creating a particular effect onthe fabric, called tuck stitch .
Miss Stitch Formation
High-butt and low-butt needles are also needed for the formation of the miss stitch (picture 3).
Picture 3 – Miss Stitch formation
The cam (with a half-way tucking cam and looping cam) meets with the needles: the high-butt needles rise while low-butt needles remain in a non-knitting position. During the downward stroke, the needles which have raised till their maximum height and have transferred the loops on the stem, are fed with a new thread. With the successive downward stroke the latches are closed and the loops is knocked over on the new thread.
Picture 1 - The stitch formationA. The needles are in the knock-over position; the loop threads are inside the hook and thelatches are closed.
B. The carriage moves forward and the cam touches the needle butt. The forward motion of the cam with the tucking cam completely out, forces the needle to move upward; the thread inside the hook opens the latch. Once the needle has reached the tucking plane, the latch is completely open and the loop is laid on it.
C. The forward motion of the carriage makes the needle move upward again, since the loopingcam of the cam is completely out. The needle reaches the maximum height on the looping plane and the stitch is transferred from the open latch to the needle stem. This sudden motion can cause a backstroke, that is a reaction of the latch, which could accidentally close with a possible unsuccessful feeding of the new thread and a consequent knock-over failure. This would lead to the formation of a hole or the starting of a run in the fabric. In order to avoid this, the brushes ensure that the latch opens.
D. Once the maximum height has been reached, the needle is lowered, driven by the loweringcam; after reaching the tucking plane, the thread guide starts working, feeding the thread;the loop rises slightly on the stem and enters the space between the stem and the open latch.
E. The needle continues its downward stroke; the loop touches the latch and makes it rotateand close.
F. The needle reaches the bottom, i.e. the knock-over plane; the previous stitch, after closingcompletely the latch, knocks over on the new thread, forcing it to take up the typicalcurvilinear shape.
Tuck Stitch Formation
Two consecutive strokes of the carriage are necessary to form the tuck stitch (picture 2).
Picture 2 – Tuck stitch formation
During the first stroke, the tucking cam of the cam is out and the looping cam is not working.Therefore the needle only raises as high as the tucking plane; the loop cannot slip on the stem,and therefore remains inside the hook after having completely opened the latch, in this wayallowing the yarn to be fed.During the second stroke both the tucking cam and the looping cam are activated; the needlerises up to the maximum height allowing the loop and the yarn to travel along the stem.Thereafter, the needle is fed with the thread for the second time; the loop and the first yarn closethe latch and knock over on the new yarn.The first yarn does not knock over as a knit stitch but takes a particular position, and fixes ontop of the previous knit stitch and at the bottom of the new one, creating a particular effect onthe fabric, called tuck stitch .
Miss Stitch Formation
High-butt and low-butt needles are also needed for the formation of the miss stitch (picture 3).
Picture 3 – Miss Stitch formation
The cam (with a half-way tucking cam and looping cam) meets with the needles: the high-butt needles rise while low-butt needles remain in a non-knitting position. During the downward stroke, the needles which have raised till their maximum height and have transferred the loops on the stem, are fed with a new thread. With the successive downward stroke the latches are closed and the loops is knocked over on the new thread.
No comments:
Post a Comment