FIG. 85.
In order to make each link in these chains represent any number of picks, and thus prevent long cumbersome chains, the mechanism shown at Figs. [84] to [87] is employed. The barrel A in [Fig. 84] is the same as barrel A in [Fig. 82], and carries the chains for lifting the levers B and C. At the end of the barrel the star wheel I is fixed, and this star wheel is turned by the pins J. These pins are worked by a clutch motion shown at [Fig. 86], by which they can be withdrawn from gear with the star wheel as desired. The pins KK are fixed, and turn one tooth of the star wheel Y every pick, the wheel M having twice the number of teeth contained in L, which is on the crank shaft of the loom. The star wheel Y is fast to the end of a small octagonal barrel, which carries a pattern chain N composed of small metal cards, and we have seen how this barrel is turned one division every pick. Above this pattern chain N a finger, O ([Fig. 86]), is placed, and is lifted up against a spring every pick by the cam P on the face of the wheel M. When the finger is up, the pins JJ are taken inside the wheel M, as shown at [Fig. 86]. The cam P only raises the finger a sufficient length of time to allow the barrel Y to be turned round, and if there is a blank in the cards opposite the finger O when it is let down by the cam it will still keep the pins J inside the wheel, and will thus prevent either of them from engaging with the star wheel I, and will leave the boxes unchanged. This can be repeated any number of picks. If a change is required in the boxes, a hole is placed opposite the finger O, and when it is let down the pins J project through the wheel M (as indicated by the dotted lines in [Fig. 86]), and the star wheel I will thus be turned one tooth, and the chain can make the change required in the boxes.
FIG. 86.
FIG. 87.
[Fig. 87] is another view of the cam-shaped projection P, which raises the finger every pick, and [Fig. 85] is another view of the chain barrel A. The letters in the six Figs. [82] to [87] inclusive refer to the same parts in each case.
In this way the chains on A are rarely required to be very long, as one link may be made to represent any number of picks from one upwards. Of course a separate card on Y is required for each pick, but these are very small, only about 1½ inch in length, and a large pattern can be made with very little trouble.
When a Jacquard is used on one of these looms it is sometimes necessary to work the pattern from the Jacquard cards. This can be done in a very simple manner by covering the hole in the barrel carrying the cards N with a metal plate, which is held over the hole by a spring. When a change is required in the boxes, a Jacquard hook pulls the plate from over the hole, and allows the finger O to drop, and thus causes the star wheel I to be engaged by the pins J.