Fig. 24
In some machines there is no spring-box. The hooks are made double, as shown in [Fig. 25], and rods, as a, a, run along between the rows of hooks; the spring of the double wire keeps the hooks steady. There is a clap-board used, similar to that in the French draw loom, ([Fig. 13]), which is pressed against the needles with springs; this board is connected with the face-plate by a bar at each end, forming a frame. The needles do not project much through the face-plate, but when the cylinder is pressed against it, it slides back on the needles, and presses the clap-board back, which also allows those needles to go back which the card presses against. The needles are not looped on the hooks, but have a turned catch in front of them as shown. The bottom of the hook rests on a hole board, C, through which the tail cords pass; and through the hooks at D are wires fixed in a frame which rises and falls when the hooks are raised, and keeps them from turning round, same as explained in [Fig. 15]. Machines of this description are at present being made in France, and work with a rising and falling shed, which will be hereafter explained (see [Fig. 30]).
Fig. 25 Fig. 26 Fig. 27
In working, the card cylinder must be so set that it will come forward fair on the needles—that is, that when it comes forward the points of the needles will enter fair into the centres of the holes in it. For the purpose of setting it there must be provision made in the fittings so that it can be moved laterally or vertically. In the swing motion the frame can be moved laterally by means of the two screw studs on which it hangs. C, [Fig. 27], shows the bearing on which the stud of the cylinder revolves. This bearing can be raised up or down in the frame R—a side view of which is given at S—by slackening the bolt B with the wing nut A, and adjusting the bearing with the set screw D or E.
A method commonly adopted by tacklers or tuners to see that the needles are perfectly fair in the centres of the holes in the cylinder, is to rub their fingers on some dirty oil, and touch over the points of the needles with it. They then bring in the cylinder against the needles with a card on it, in which about half of the holes are cut. The points of the needles mark the card where there are no holes, and it can easily be seen whether the mark is in the centre of where a hole should be, or not.
One of the best bearings and attachments for a cylinder with a horizontal slide motion is given in [Fig. 26]. D is the bearing for the cylinder E, and C the bolts for setting it. F F is the bracket which holds the hammer and bearings, which can be set in position on the slide bar B by the bolt A. I is the hammer held down by the spring H attached to the rod G.
The cards are kept in position on the cylinder by pegs or studs, originally made of wood, and driven into the cylinder. Now they are made of brass, and set in a slotted bracket, so that they can be shifted in order to have the holes in the cards corresponding exactly with those in the cylinder. The pegs should also be set on springs, so that if a card gets off them, and between them and the needle plate, they will yield or sink into the cylinder, and not break the card. In all good machines they are made in this way.
When the motion for driving the cylinder is not fitted with an escapement for the purpose of turning back the cards, it is necessary for the convenience of the weaver to have a motion on the machine for the purpose.