FIG. 162.
FIG. 163.
The treadles are operated by tappets, and those operating treadles E and F must do so every pick, whilst the treadle D only requires to be pressed down once every two picks, because the spring K pulls the needle rack to the right. The tappets are shown at [Fig. 163], where it will be seen that when the treadle E is down, F is up, and the rack will be dropped and the false reed lifted; and when the treadle F is pressed down—letting the rack be pulled up by the springs, the treadle D is pressed down, which pulls the rack to the left as far as the groove in the wheel will allow it to move.
FIG. 164.
FIG. 165.
At the back of the lappet wheel a face cam L ([Fig. 164]) acts upon a lever, MN, centred at P, and the bent arm of the lever N pushes the hook C on to the treadle F when the spot figure is being formed, and when there is no figuring going on the hook is pulled out of the way of the treadle, and so the motion of the rack is stopped.
The pattern is formed by the groove in the lappet wheel ([Fig. 165]), and in drawing this the wheel is divided into as many teeth as there are picks in the pattern. The wheel is usually made of hard wood, and after being smoothed off a number of circles are described, the distance between each being equal to one dent in the reed. Suppose the pattern is a continuous one, as at [Fig. 166], the picks shown on paper being in addition to the ground picks. In drawing a wheel for this pattern the number of teeth required will be twenty-four, as there are this number of picks in the pattern.