Warps Protector Motion | Working Principle of Loose Reed Warps Protector

Warps Protector Motion
To protect the warp yarn/reed/shuttle in case of trapping the shuttle in the shed is the function of warp protector motion. The shuttle failure or the shuttle trap inside the warp shed may cause many broken ends during the forward movement of the sley. In order to prevent this from occurring a device is necessary to stop the loom whenever the shuttle fails to reach the shuttle box.

Types of Warps Protector Motion.
Warp protector are two types
  1. Loose reed warps protector
  2. Fast reed warp protector
Now, we discuss only Loose reed warps protector .

Loose Reed Warps Protector:
The principle of the mechanism is that the reed is forced out of its support whenever the shuttle is trapped in the shed and this backward inside movement of the reed will cause a knock off device to act and stop the loom.

The reed A is held at the top of the slotted reed cap B. the bottom part of the reed is held firmly against the raceboard C by the reed case D which extends the whole width of the reed. This reed case is connected to a stop rod S by means of several brackets. The stop rod also extends the width of the sley and it is fixed to the sley below the raceboard. There are two, three or four frogs E, depending upon the width of the loom, mounted on the stop rod. In front of each frog there is a heater F fixed by means of a bracket to the breast beam.

Loose reed warps protector
A= Reed
B= Reed cap
C= Race board
D= Reed case
E= Frog
F= Heater
G= Bowl
H= Bow spring
J= Stop rod finger
S= Stop rod
K= Serrated bracket
L= Starting handle

During the normal working of the loom there are three devices to keep the reed firm:
  • Frog E engaging the heater F.
  • Bowl G riding the bow spring H.
  • A light spiral spring I.
Frog and Heater:
When the sley moves forward the frogs slide under the heaters thus locking the reed firmly for a good beat up of weft.

Bowl and Bow Spring:
During the backward movement of the sley the bowl G rides on the flat bow spring H and keeps the reed firm to enable the smooth flight of the shuttle during it traverse from one box to another.

Spiral Spring:
The light spiral spring keeps the reed case tensioned all the time. A stop rod finger J is also mounted on the stop rod, and facing this finger is a serrated bracket K fixed to the starting handle L. When the shuttle is trapped in the warp shed it presses against the base of the reed during the forward movement of the sley, with the result the reed swung backwards turning the stop rod S through the reed case. When the stop rod is turned all the frogs and the stop rod finger are raised. During further forward movement of the sley the frogs ride over their respective heaters and the stop rod finger hits the serrated bracket and stop the loom. The frogs riding over the heaters will enable the reed case to move backwards easily.

The loose reed motion is only intended for light and medium weight fabrics. It is therefore necessary that the spiral spring I should only be strong enough to prevent the reed case from vibrating during running of the loom. If it is too strong the shuttle has to exert a greater force to push the reed back, which means more strain on the warp threads. Delicate warp used for light weight fabrics will not stand such strains with the result more warp breakage will occur. 
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Mazharul Islam Kiron is a textile consultant and researcher on online business promotion. He is working with one European textile machinery company as a country agent. He is also a contributor of Wikipedia.

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