Suttle and picking

1. SHUTTLE AND PICKING
CHECKING

2. CONTENT
1)INTRODUCATION
2)OBJECT OF PICKING
3)PRINCIPLES OF PICKING
4)TYPES OF PICKING MECHANISMS
5)NEGATIVE PICKING MECHANISM
1. TYPES
2. CONSTRUCTION
3. WORING

3. INTRODUCTION
The action of inserting weft yarn
through the warp yarns is called
picking. Picking is the second primary
motion in weaving. Picking motion
propels the weft from one end of the
loom to the other.

4. 1. Negative picking mechanism or
conventional Picking mechanism
2. Positive picking mechanism or
unconventional picking mechanism
Types of Picking Mechanism
Picking mechanisms

5. Negative picking mechanism or
conventional Picking mechanism
In this mechanisın, a carrier known as shuttle
carries the weft yarn by passing the shuttle
through the warp shed.The main functions of
the conventional or negative picking
mechanism

6. . Positive picking mechanism or
unconventional picking mechanism
In this mechanism, the weft yarn is inserted
through the warp shed directly or positively by
air, water, a projectile, a rapier or a needle.
illustrate weft insertions of the direct, positive
type.

7. The two main types of negative picking
mechanisms
i. Over pick mechanism -Cone over pick
mechanism
ii. Under pick mechanism – Side lever under
pick mechanism
Negative picking mechanism Types

8. Cone over pick mechanism
• The picking tappet is fixed to the bottom shaft .
• The picking tappet consists of three parts , the boss , shell , and nose .
• The boss is keyed onto o the bottom shaft and it carries the shell portion.
• The picking nose bit touches a tapered cone , which is connected to a vertical
shaft .
• The vertical shaft is held in the vertical position by two brackets namely the
top bracket and the foot step bearing.
• The bottom Corrugate plate is fixed rigidly . The top Corrugated plate is
placed upon the bottom plate such that is position can be altered to change the
strength of the pick .

9. Cone over picking mechanism

10. • The picking arm or stick , made of wood , it’s fixed to the top plate by a grooved cup and nut .
• A picking strap or picking band is made of leather , is connected to the stick or arm by a pin.
• The picking band passes down and is connected to a picker , which is loosely and freely mounted
on a spindie .
• The picker touches the tip of the shuttle .
• A similar arrangement is provided on the other side of the loom . But , the nose portion of the
picking tappet is tilted by 180 degrees .
WORKING
When the bottom shaft rotates , the nose of the tappet also rotates .When the nose comes against the cone , it
strikes the cone . This causes a partial rotary movement of the vertical shaft The picking arm or picking stick thes
swings inward with sufficient velocity to drive the picker . The shuttle being in contact with the tip of the picker is
pushed across the shed . The picking arm is returned to the original position by the spring . The cone is always kept
in contact with the shell portion by the spring . For the next pick , the tappet on the other side is set in motion and
the shuttle will be pushed out of the other box . for every rotation of the bottom shaft two picks are inserted .

11. SIDE LEVER UNDER PICK MECHANISM
CONSTRUCTION
•This mechanism belongs to under pick looms. In this mechanism a circular
disc is fixed to the bottom shaft.
•The disc contains slots to carry a bowl. A side lever which is below the
circular disc carries a picking shoe at the centre of the lever and it is connected
to a bracket and spring at the back end.
•A guide is used to guide the side lever during its motion. The lower front end
of the side lever touches an elbow.
•The elbow carries the picking stick. A picker is loosely mounted at the top of
the picking stick. The elbow is connected to a coiled spring which is in a
housing bracket.

12. SIDE LEVER UNDER PICK MECHANISM

13. • The elbow is connected at the bottom to a rocking shaft.
•A buffer is fixed to the side frame of the loom and a check strap is fixed in
the slot of the bracket provided below the shuttle box.
•The picker is in kept in contact with the tip of the shuttle when it is in the
shuttle box.
A similar arrangement is provided at the other side of the loom and the
circular disc bowl is fixed at 180o opposite interval.
WORKING :-
As the bottom shaft rotates, the bowl in the circular disc presses the picking
shoe in the side lever and the side lever lower front end presses the picking
stick elbow which makes the picking stick to move forward to hit the shuttle
into the shed.
The check strap is used to reduce the velocity of the shuttle and prevent it
from rebounding. The buffer is used to absorb the shock created during the
motion of the picking stick.

14. THANK YOU