WRIGHT SHAW’S DROP-BOX.
The principle of this motion will be understood from the diagram, [Fig. 77]. The essential feature of this invention is a forked rack, G, suspended from the free end of a treadle lever, E, fulcrumed at F, and carrying a bowl or runner, D, near the centre. At one end of the second motion or picking shaft, A, of the loom, are two cams, B and C, either of which may be brought underneath the treadle bowl at will, so as to raise the treadle and forked rack once during each revolution of the picking shaft, corresponding to two picks. Passing midway between the two prongs, H, H′, of the fork is a short shaft, upon which are secured two toothed wheels, I and J. Wheel I is so placed that the teeth on either side of the rack may be put into engagement with its teeth just before the fork rises, so as to turn the wheel in either direction; or the rack may occupy a neutral position when rising, in which event the wheel remains stationary. In any case, the racks are always clear of the wheel when descending. Immediately in front of wheel I is another similar wheel J, whose teeth are in permanent engagement with those of a rack, K (an extension, L, of which supports the shuttle-boxes, M). Thus, if rack H′ is put into gear with wheel I, boxes will be depressed as the rack rises; but if rack H operates, the boxes will be raised. One box, or two boxes, only, may be either raised or dropped at one change, according to which rack and which cam is put into operation. The smaller cam moves one box, and the larger cam two boxes, either up or down.
FIG. 77.
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The selection of racks and cams is made by pattern cards (detached) which pass over an octagonal prism, N. The cards are presented separately, once in two picks, to three selecting needles, 1, 2, 3. The two outer needles, 1, 3, are attached one at each end of a double arm secured at the top of a long vertical shaft, O, the bottom of which communicates with the forked rack G. Thus a depression of boxes is effected by a blank part of a card pressing against needle 1, and an elevation of boxes by pressing back needle 3. Shaft O is loosely contained within a long tube or sleeve, P, which carries a short arm, R, at the top, and a forked clutch, Q, which acts upon the boss of cams, B and C. If it is desired to move two boxes, needle 2 is pressed back, thereby causing an inclined piece, S, secured to it, to act upon arm R so as to slightly turn the sleeve P, and move the larger cam C under the treadle bowl at a time when the short side of the cam is uppermost, as indicated in the diagram, [Fig. 77]. At one point, the larger and outer cam is slightly lower than the smaller one, and can be readily moved under the bowl.
The various changes which can be made by this motion may be seen by referring to the cards at [Fig. 77]. When there is a blank opposite the first needle only, the rack H′ is pushed to the left and the boxes are moved “down one.” When there is a blank opposite the third needle only, rack H is moved to the right and the boxes are forced “up one.” When there are blanks opposite the first and second needles, they are pushed backward, thus moving rack H′ to the left, and also forcing the larger cam under the treadle bowl, in which case the boxes will be moved “down two.” When there are blanks opposite the second and third needles, they are pushed backward, and the boxes are “raised two.” When there are three holes in the card, the racks, when lifted, miss the wheel, and there is “no change” in the boxes. It will be seen that the boxes may be moved either up or down, a space of one or two boxes only at a time. There may be more than three boxes, as many as five being regularly used; but if there were five, it would not be possible to change from the first box to the fourth or fifth. The greatest change which can be made is from the first to the third, fourth to second, and so on.