Types of multiple box motion in power loom (semi-automatic and automatic) Eccle’s, drop box.

Types of multiple box motion in power loom (semi-automatic and automatic) Eccle’s, drop box.

POSITIVE MULTIPLE BOX MOTION.

(iii) Eccle’s Drop box motion, and Cowburn and Peck motion:-

The Cowburn and Peck and Eccle’s drop boxes are the example of double type box motions. They are very similar in operation. The Eccle’s four-box motion, which is fitted to 'Texmaco' loom is largely used in the Indian textile industry. This is illustrated in fig. 166 . An eccentric, double crank and two discs are employed in this positive box motion.

(1) The disc has a pinion B outside. The working rack C is moved up and down in two picks by an eccentric L, fixed on the extension of the bottom shaft outside the loom framing . The rod N passes down from a crank inside the two discs to the bottom box lever O , fulcrumed in the center at P. The rack C, fulcrumed at M, is moved up by the eccentric L. When the rack is up, it engages with the pinion B of disc A , being pushed forward by needle F and card cylinder G. If there is a hole against the needle in the metal card cylinder, there is no change of the position of boxes . A blank in the pattern card pushes the needle against the rack and causes the pinion B and disc A to move half a turn . The card cylinder G is oscillated by a tappet K on the bottom shaft on bowl J through the rod H, fulcrumed at I. The needle F also controls the action of the locking catch D through link E.

Fig.166 Eccle's drop box motion.

(2) The formation of the double disc can be seen at figs, 167A, B, C, D. The disc A has a pin attached to it , to which is connected a crank shaft, and the opposite end of the crank fits into a slot on the other disc A’. When the fixed pin disc A is half turned , there is a lift or depression of one box. But when the slotted disc A' is half turned the pin slides in the slot and there is a lift or depression of two boxes.

fig.no. 167 A, B , C, D Eccles Drop box motion.

(3) {a} The action of the double disc is shown at fig. 167A, the first box is inline with the sleyrace, both disc being up .

{b} At fig. 167 B, a half turn of the fixed pin disc A brings the pin to the lowest position and the crank slides down in the slot in disc A’, placing the second box in line with the sleyrace.

{c} Starting from the first position if the slotted disc A' is turned half way round, the fixed pin disc A being stationary, box in line with the sleyrace as at fig. 167 C.

{d} Again, starting from the first position, turning of both the discs together half way round in the same direction as at fig. 167 D, places the fourth box in line for picking.

The fig.167 D, gives lift of three boxes, placing the fourth box inline with the sleyrace. By turning again the two discs the next half way found in the same direction, depression of three boxes may be obtained. Each disc has one rack , one needle and one locking catch for turning it.

AVANTAGES:-

The advantage of using eccentric is that the boxes begin to move slowly, and the speed increases as the center of lift is reached, then they slow down again towards the end of the stroke . In this motion boxes begins to move at the end of the stroke. In this motion, boxes begin to move at 335° and complete their movement at 135°, that is 45° past the front center position of the crank.

Card saving device:-

(i) A card saving device is fitted to Eccle’s drop box motion where two star wheels, one above the other, are reverse movement to the card cylinder and the bottom star wheel puts the same pattern card against the needle for successive pick.

(ii) To work the card saving motion, a central hole is provided in the flat steel cards of the pattern chain . This controls the action of a third rack, causing it to engage with a pinion that turns a secondary card barrel of wooden lags.

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