Wednesday, March 24, 2021

Double - lifts and single-cylinder Jacquard shedding mechanism


Double lifts and single cylinder jacquard shedding mechanism


Structure of double lift and single cylinder jacquard:

There are two griffes used in the double lift jacquard mechanism. Eight knives are mounted on each griffe. In the double lift jacquard, two hooks are used for one end. Both the hooks get paired to each other through a pairing link. The selection needle has two kinks in it. These two kinks (eyes) are engaged with two hooks. The pressure spring is fitted at the rear end of the needle. This spring tends to push the needle toward the cylinder. The front end of the needle passes through the needle board. A pattern cylinder gets mounted in front of the front end of the needle. The doubled end of the hook rests upon a slotted grid. Two hooks get paired with each other. The upper end of the neck cord gets connected to the pairing link. The lower end of the neck cord firstly passes through the hole of the tug board. The lower end of the neck cord is connected with the upper end of the harness cord through the s-link. The lower end of the harness cord passes through-hole of the comber board. The lower end of this harness cord gets connected with the upper end of the heald wire. A lingo ( dead weight ) is hanged at the lower end of the heald wire.




working principle of double lift and single cylinder jacquard shedding mechanism:


The double lifts and single-cylinder jacquard receives motion through the bottom shaft. A sprocket wheel is mounted on the bottom shaft of the loom. This sprocket wheel is connected to another sprocket wheel mounted on the jacquard shaft through a chain. The eccentric cams impart up and down movement to the griffes. Both the griffes make a reciprocating motion. When the one griffe reaches the bottom dead center of the jacquard, the other griffe reaches the top dead center position of the jacquard. Both griffes change their positions after the half revolution of the jacquard shaft. The selection of the hooks according to the punching of holes in the card takes place when the griffe reaches the bottom dead center. The pattern cylinder pushes the front ends of the needle. If there is a hole punched in the card, the front end of the needle enters into the perforated pattern cylinder and the respective hook gets engaged with a respective knife. If there is a blank portion in the card, the respective needle gets pushed toward the spring box and the respective hook gets disengaged from the knife. The reciprocating griffes carry engaged hooks in the upward direction. Since the hook gets connected to the heald wire through the neck cord and harness cord so that the heald wire also moves in an upward direction with hooks. Thus the end drawn through the eye of heald wire goes in an upward direction. The lingo brings the hook in a downward position. After half revolution of jacquard, the other set of hooks get engaged with the second griffe according to design, and this griffe carries the engaged hook in the upward direction. Semi-open shed forms in this jacquard. Two hooks are used to lift one end.

Please watch below video about double lift and single cylinder Jacquard shedding mechanism in hindi

https://www.textileadvisor.com/2021/03/double-lifts-and-single-cylinder.html?m=1




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