TYPES OF JACQUARD SHEDDING MECHANISM(double lift double cylinder):-

Types of Jacquard shedding mechanism:-

There are many types Jacquard shedding mechanism, they are,

1. Double-lift and double cylinder Jacquard shedding mechanism.

2.  Double-lift and single cylinder Jacquard shedding mechanism.

3. Single lift and single cylinder Jacquard shedding mechanism.

4. Verdol Jacquard or Pitch Jacquard Shedding mechanism. 

(1) Double-lift and double cylinder jacquard shedding mechanism:-

STRUCTURE OF DOUBLE-LIFT AND DOUBLE CYLINDER JACQUARD SHEDDING MECHANISM.

There are two griffes used in this Jacquard shedding mechanism. Eight knives are mounted on the first griffe and eight knives mounted on the second griffe. The griffe carries upward the odd number of hooks and the second griffe carries even number of hooks in the upward direction. In this jacquard shedding mechanism two kinds of hooks are used . The upper ends of odd number hooks get inclined toward the pattern cylinder getting used for the selection of odd number hooks and the upper end even number get inclined towards the pattern cylinder getting used for the selection of even number hooks. The number of hook used in this mechanism is just double the figuring capacity of the Jacquard. 800 hooks are used for 400 figured capacity Jacquard. Two sets of needles are used to control the selection in this Jacquard. Needle E control the selection of odd number hooks while needle C control the selection of even number hooks. The front end A&B of each needle pass through the holes of respective needle boards. The spring box are mounted just behind the rear ends of each needle E&C. The pressure spring mounted at the rear end of each needle tend to push the needle toward the respective pattern cylinder. Two pattern cylinder are mounted in front of the needle boards. One pattern cylinder performs a selection of hooks for even number of picks. One hook of odd number of end and one hook for even number get paired through the link. The doubled end each hook rests upon the slotted grid. The upper end of the neck cord is connected with the pairing link. The neck cord passes through the hole of the tug board, then the lower end of the neck cord gets connected with the upper end of the harness cord. Now the harness cord pass through the hole of the comber board. The lower end of this harness cord is connected to the upper end of the heald wire. A lingo is connected with the lower end of the heald wire to give weight to heald wire for downward due to gravity.

Fig. Of the double-lift and double cylinder jacquard shedding mechanism.

The mechanism receives rotary motion through the bottom shaft. One sprocket wheel is mounted on the loom bottom shaft wheel, while the another sprocket wheel of the same number of teeth mounted on the jacquard shaft. The sprocket wheels are connected to each other through an endless chain. The griffe receive the reciprocating motion through eccentric cam mounted on the Jacquard. When the first griffe reached the top dead center of the Jacquard, the second griffe reaches the bottom dead centre of the jacquard. When the jacquard shaft rotates , both griffes cross each other. When the griffe reaches the bottom center position, it comes slightly down in the bottom center position, it comes slightly down in comparison to the upper inclined end of the hook . Now the pattern cylinder pushes the front end of the needle. If there is a hole punched in the card , the front end of the needle gets entered into the hole of the perforated pattern cylinder and the hook gets engaged with a knife. If there is a blank portion in the designed card , the needle gets pushed toward the spring box and the hook gets disengaged from knife. When the griffe starts to travel from the bottom dead centre position to the top dead centre position it carries the engaged hooks in the upward direction. The second griffe reaches the bottom dead centre now. The other pattern cylinder pushes the front end of the needle and hooks are selected. When the second griffe travels upward , it carries engaged hooks with it. The right hand side pattern cylinder performs the selection of odd number of pick , while the left hand side pattern cylinder performs the selection of even number picks. Since the upper end of the heald wire gets connected to hooks pairing link through the neck cord and harness cord lift the heald wire in an upward direction.  

The lingo brings the hook in a down position. The separate pattern chain are prepared in this jacquard. A chain of odd number pick is in the left side of the pattern cylinder. The number of picks in both chain should be equal.

Ref:-https://en.m.wikipdia.org.