Cotton Manufacturing

by Christopher Parkinson Brooks

The Drop-box Loom.

For changing the shuttle a drop-box loom is generally employed. In a double drop-box machine six boxes may be used at each side of the loom, any one of which may be brought into action, giving a scope of eleven colours of weft. The single drop box is, however, more usually employed, with four or six boxes at one side of the loom, only giving four or six colours, but not allowing less than two picks of the same colour to be put in. To insert single picks of colour a double-box loom is used, and possesses a special pick-and-pick arrangement (uncommon in the cotton trade) to admit of its picking twice consecutively from either side of the loom. The number of boxes just mentioned is seldom met with in the cotton trade, three and four boxes being the usual sizes. The single four-shuttle drop box carries a frame at one end of the slay in which the boxes or shelves rise or fall. These boxes contain the shuttles, and by suitable regulating motions the boxes may be shifted so as to bring any one shuttle level with the shuttle race and in front of the picker. The spindle is duplicated, and the couple is placed in front of the box, not above, as in a plain over-pick loom. The picker is broad and is without nib, fixed in a horizontal position, so as to act on any one of the shuttles which may be placed before it. The principal drop-box regulating motions are Diggle’s chain and Wright Shaw’s motion.

DIGGLE’S CHAIN MOTION.

Diggle’s chain is noted for short patterns, is simple in construction, and sure in its action. Attached to the loom top is a star wheel A and barrel B revolving on a stud. The barrel carries a chain C, of different sizes of links united by pins; the star wheel receives its motion through a train of wheels from the crank-shaft, of which D and E are connections. The links of the chain support a lever F, connected with another lever G at the loom side supporting the drop boxes. For a four-shuttle box the links are of four heights, the deepest raising the boxes to the highest point, while the lowest link supports the levers so that the boxes are at the bottom, with the top shuttle level with the shuttle race. The chain is arranged so that a sufficient number of links of the same height are placed together where several picks of the same colour are required. The shapes of the links are varied to adapt the lifts from or sinking to different boxes—thus, for a four-box loom twenty different shapes of links may be used to give lifts or depressions from any box of the four to any other; their arrangement in chain depends on the before-mentioned principle. A plate of links is shown at [Fig. 72]. They will be seen to be of four different heights. A 44-inch loom of this make may run 150 picks per minute. The change of shuttle is made immediately the shuttle enters the box. We are not able to change the shuttle at less intervals than two picks, but can do so at greater intervals—say, for example, once in four picks.

FIG. 71.

FIG. 72.

WRIGHT SHAW MOTION.

The motion called, after its inventor, the Wright Shaw motion is perhaps more suitable to cotton goods. Indeed, in Manchester, near to which city it was invented and is manufactured, it finds much favour in the check trade. A greatly improved motion has been recently introduced by Mr. Wright Shaw, but as the older form is in commoner use, we will refer to the latter.

FIG. 73.

[Fig. 73] shows a sketch of this machine, in which the parts will be clearly seen. It is the make of Messrs. Henry Livesey, Limited, of Blackburn, but is on the Wright Shaw principle improved. The shuttle box is supported and moved by a rack and pinion; this pinion shaft is actuated by a forked rack supported on a pivot at the end of a lever, so as to gear with either side of another wheel on the pinion shaft. The lever is driven by a cam, and raises and lowers the fork. The pattern chain consists of iron plates which are thin and narrow, thus enabling a longer pattern to be obtained than is possible by the previously described motion. These plates are linked together by elastic bands, and each contains two peg holes, and also one, two, or three larger holes to correspond with the points of the three-pattern chain needles. The pattern chain passes round a square block perforated to correspond with the needles, and driven at the speed of a quarter of a revolution for each two picks. The pegs on it carry the pattern plates round with the block. The needles are arranged horizontally, points facing pattern block. The outer needles regulate whether the right or left leg of the fork shall be in contact with the wheel on pinion shaft, to determine whether the reciprocation shall be upwards or downwards. A hole in either one side or the other of the plate regulates this; should both sides be perforated, the fork remains in its previous position. The fork is raised and depressed by a lever, actuated by one of two cams—one to move the boxes one shelf, and the other to skip a shelf, thus moving two boxes. These cams are changeable, and operate on one end of the lever, while the fork is suspended to the other end. The central needle decides which shall be in action, as it carries a projection which, when pushed back, thrusts the larger sweep cam into action. It is easy, therefore, to understand the action of these cards; three holes give no movement; two holes, with a blank at one side, put the fork into gear with the corresponding side of the pinion wheel; and in the case of two blanks, the one in the centre puts two-box stroke in action, and the side blank puts the fork in gear at one side. One blank at the right side causes a rise, or, at the left side, a fall. The five forms of plate are:—

Rising one means that the box is risen to the next shelf; rising two is risen to the next shelf but one, skipping one. This style of drop box can be driven at the speed of 170 picks per minute. Generally, a weaver attends to three of these looms, and an overlooker to from 50 to 60. For the check shirting trade looms to weave from 30-inch to 37-inch cloth are used.

OTHER MOTIONS.

An ingenious drop-box motion is manufactured by a Burnley firm, by which the weight of supporting the boxes, etc., is altogether removed from the pattern chain, which is consequently made of less cumbrous construction. Other firms claim decided advantages in respect of a greater skip than either Diggle’s or Wright Shaw’s motions—e.g., from the first to the sixth box. Skips of this extent are obtained principally by using several eccentric cams. One of these may lift a single box, a second may raise the boxes two spaces, and their effect in combination is a lift of three shuttles, and so on for greater effects.

CIRCULAR BOXES.

Circular boxes are seldom used for cotton goods. In this arrangement the shuttles are fixed in grooves formed in a block revolving at the slay end, and drawn round in either direction by hooks, one being placed at each side of the revolving barrel. The movement of the hooks is regulated by a pattern chain. The speed is about the same as a Wright Shaw motion.

GENERAL.

Any of these types of boxes may be used with the over-pick, and either with tappets, dobby, or jacquard shedding. Attempts have recently been made to apply the drop-box principle to a system of replenishing the loom with three or four cops of weft without a stoppage, by having them previously placed in the shelves and lowered on the breakage or running-off of the previous weft.