Weft replenishment motion (drop box & vibrating box):-

Weft replenishment motion (drop box & vibrating box):-

Multiple Box in Handloom:-

Types of Multiple Shuttle Boxes:

In producing checks in fabric with more than one color, count or material, a sley containing multiple shuttle boxes is generally used , because the process of alternately changing the shuttle by hand is very laborious and slow. Most handlooms are constructed with multiple boxes at one end of the sley , and a single box at the other end. This type of auxiliary motion of weaving is known as “multiple box loom". There are two types of multiple box motion commonly used in handloom industry, they are,

(1) Drop-box motion, and

(2) Vibrating box motion.

In power loom, multiple Drop-boxes may be used at one end or both ends of the sley. But when a loom has multiple boxes at both ends of the sley, it is known as “pick and pick loom". Multiple box looms produce all kind of weft pattern.

Drop Box Motion:-

In this type of motion, the boxes are made to move vertically up and down. The sley is so constructed that any of the shuttle boxes may be brought to level with the sley race, as required by the weft pattern. Ordinarily, two shuttle-boxes at one end and a single shuttle box at the other end are used in Drop-boxes handlooms . The single-box is placed on the extension of the slay race at one end , whilst the two or sometimes more boxes are placed outside the sley race at the other end on the same vertical plane. Fig. 28 shows a two-box motion is placed at one end of the sley.

Fig . 28 of drop box motion in Handloom sley at one end in the Sley and a single shuttle box at other end.

As in the figure shown above the upper box A is normally inline with the race C. When the required number of picks of one color or kind is inserted through the shed from this box , the lower shuttle-box B will be brought into line with the sley race for use of the second colour. For this purpose, the lower box is raised by pressing a lever D down to the sley cap E by the weaver’s hand. This lever remains fitted with the lower shuttle box and is extended to the center of the reed cap. Again when it is required to use the upper box, the lever is liberated from the clutch of the weaver’s left hand and the box drops down. In this way , the upper box comes in line with the sley race and any number of picks may now will be inserted from this box. This any of two boxes may be brought in line with the sley race, as required by the weft pattern . Only even number of picks of a colour or count can be inserted by this type of drop box motion. In certain handloom weaving center drop boxes are preferred whilst in other places vibrating boxes are used.

(2) VIBRATING BOX MOTION:-

In this type of multiple box motion , the boxes oscillate back ward and forward and any of them may be brought into operation as required . The vibrating boxes can more easily be operated than drop-boxes by mens of a handle extended upto the middle of the reed cap. This is shown at fig.29.

When the box A is in operation, the lower box B stands side way with the shuttle . Any of the two shuttle may be placed in front of the picker C by raising the handle D, according to the weft pattern of the fabric. The picker does not change its position, but only the boxes are alternately pressed forward and backward. This types of multipl-box motion is commonly used in handlooms, but in this method it is difficult to operate more than two vibrating boxes.

Fig. 29 vibrating box fitted in the Sley at one end and a single shuttle box at the other end.

When multiple-boxes are employed at one end of the sley and a single box at the other end, the repeat of the weft pattern must always be in two picks or its multiples. A single pick of one color or count in repeat can only be obtained by employing 'pick and pick' loom in which multiple boxes are introduced at both ends of sley. The latter has practically little use in the handloom industry.

A loom fitted with multiple-boxes at one end of the sley, cannot have less than two picks of any color or count, as the shuttle must reach the box from which it started its journey. When a single color is required to be used for each pick, multiple boxes must be operated from both the ends of the sley. This type of auxiliary motin in a loom with multiple-boxes at both ends of the sley is known as a 'Pick-at-will' motion. Vibrating boxes are not used in power looms but instead circular boxes are used , whereas drop boxes are used both in handlooms andin power looms.

Ref:-Weaving Mechanism Book Vol. I by Prof. N. N. Banerjee.