Fig. 25.
The time to set the crank is to have it level, that is, the two extreme points horizontal, when the crank shaft is a little ahead of the bottom center, or to have the reed about 1½ inches from the cloth when the shed is level.
Fig. 26. Showing Connection of Neck Cords to Hooks.
Owing to the general formation of the double action machine, that is, the use of two hooks for one set of harness threads, there is a somewhat uneven movement to the harnesses. When a griffe is descending and some of the hooks that are on the griffe are to be lifted for the next shed, and the hooks are passing each other at the center of movement, the angle of the harness threads is changed, for as one hook is lifted from the top shed, the neck cord attached to the hook that is at the bottom is slack. When this hook is raised for the next pick, at the point when all the slack cord is taken up, the uneven movement is caused, the harnesses swinging over into the line with the lifting hook. The results from this movement are not so harmful if the jacquard is tied up proportionally and run at the right speed; but when the machine is run too fast and the lingoes are too light, also when the neck cord is too short, a large amount of trouble is caused. Instead of connecting the harnesses to the hooks, by means of two neck cords, one is used as shown in Fig. [26]. The link answers the purpose for which it is intended, that is, to take away the slack neck cord. It also reduced the uneven movement. However, unless the hooks are kept perfectly straight, the link will not work, and it is common for a hook to be bent a little underneath the grate.
Fig. 27. Arrangement of Needles and Hooks in Double Action Machine.
When one neck cord breaks on the ordinary double action machine, the defect is not readily seen, because the harness cord will be lifted by the other hook, unless it is a pattern where that particular hook from which the cord has broken is lifted very often. When the link is used, all the harness threads that are attached to the link will fall, owing to the use of only one neck cord; this also occurs on the single action machine.