The Jacquard Machine.
The advantage of this motion is in its enormous capacity or scope of varied working of the ends. When we are aware of the existence of 1200 hook jacquards, the capacity of which is equal to that of 30 dobbies of 40 jacks each, or giving 600 times as many different workings of the ends as a plain tappet, we immediately recognise its value. It is a machine for automatically selecting out of may be thousands of threads the end or ends required to give a desired effect in the cloth. A representation of its simplest form is shown in [Fig. 62].
Taking a 400 hook machine, the commonest size used for cotton weaving, we find a row of 8 needles or lances E of thin wire, arranged horizontally; at the left hand we see each of these attached to a spring in the spring box A, the other end projecting about 3/8-inch through a needle board B. Each lance regulates a vertical wire hooked top and bottom, and shown with each upper hook standing over its respective griffe or knife C. These griffes, eight in number, are lifted simultaneously through being connected together at the ends. The lower end of the hook rests on a wire grid J, slotted so as to allow the lower end of the hooks—to which are attached the neck cords F—to pass through. A bottom board below the bend is used for those machines which have no wire grid. To these neck cords is attached the harness—i.e., linen threads or leashes, some seven feet in length, carrying a brass mail-eye H, through which the end of warp is drawn. Just above the mail-eye the harness passes through a cumber board C, for the purpose of keeping in proper order and regulating the number of leashes per inch. At the bottom of each leash is fixed a metal weight, called a lingo, intended to pull the leash down after having been raised to form the shed.
The method of raising the ends is as follows:—A square cylinder is placed at D, and makes a quarter of a revolution at each pick. This cylinder carries a set of cards (N1, N2, N3), sheets of cardboard perforated in places. Supposing a 400 (408) machine is referred to, each card has space for 408 perforations, the holes corresponding in position with the ends of the 408 needles projecting through the needle board. A hole indicates a lift.