Chain of steels
Chain of steels
Fig. 19.1 Mechanical jacquard selection on a V-bed flat machine.
from right-to-left so that the butts of the knitting elements enter from the left, passing through four systems:
1 From the left, the first system is transferring loops from the back bed to the front bed. '4' is a loop transfer cam and '6' is a loop receiving cam. 2,3 The next two systems contain knitting cams, '2' being clearing cams and '3' being stitch cams.
4 Finally, the right system is transferring loops from the front bed to the back bed. Delivering cam '5' is introduced to raise butts onto transfer cam '4'.
The Shima model SES provides the same facilities but with only two systems, each of which contains full camming for knitting and two-way transferring; this virtually halves the width of the cam-box.
Needle jack (b) is pivotally connected to the needle and provides the single position knitting butt that can be selected to follow the raising cam (2) (Fig. 19.4) profile, lifting the needle from miss to tuck or knit.
When the tail of the needle jack is depressed by the head of the re-positionable presser jack (c), the knitting butt is sunk out of contact with the raising cam (2) and the needle remains at the height it has already reached.
Fig. 19.3 Knitting elements.
The presser jack is selectively positioned so that its pressing butt is aligned with one of three presser cam paths (A, H or B), where it can be pressed downwards by a presser cam in the cam-carriage. The needle jack can also be sunk out of action by manually pushing it under wire (iii).
The presser cam is a flat plate actuator in the cam-carriage that can be tipped so that it presses down onto the butt of a presser jack placed in its path. There are two presser cams (Fig. 19.4) projecting from beneath each raising cam (2):
The lower presser (the miss presser) covers the full width of the raising cam for presser jacks in either the H or B positions, causing the knitting butt to be out of action at miss before it can be lifted to tuck height.
The higher presser (the tuck presser) covers the top of the part of the raising cam and when in action will cause needles in the A track to remain at tuck height. When the tuck presser cam is tilted slightly, it will miss the presser butts in the A position and those needles will continue to follow the raising cam profile and be lifted to knit height.
There are 4 possible combinations of knit, tuck and miss:
1 Tuck presser cam tipped (A knit). Miss presser cam untipped (H knit, B miss).
2 Tuck presser cam tipped (A knit). Miss presser cam tipped (H miss, B knit).
3 Tuck presser cam untipped (A tuck). Miss presser cam untipped (H knit, B miss).
4 Tuck presser cam untipped (A tuck) Miss presser cam tipped (H miss, B knit).
The head of the pattern selector jack (e) rests on top of the presser, against its butt. When the selector is cammed forward, it moves the presser from position B to forward position A. Cancellation cams (9, 10, 11) move the presser from A to B. When the cam is out of action, the presser is guided only to intermediate position H for re-selection.
The selector has a tail butt (t) for raising it. Butt (r) is used to return the selector to the start position for re-selection. Selection butt (s) corresponds to one of 6 positions of the bank of actuator-selecting cams. The selection butts are set-out in descending echelon order.
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