At IV., Fig. I., the “catches” for turning the cylinder at the lantern
are illustrated. The distance of the centre of the screws which hold
the catches to the frame is 4-3/4 inches. Between these two catches the
cylinder is adjusted to the batten, and the direction of its turning is
regulated by the catch which is brought in contact with the lantern.
If the catch, _y_, turns, the cylinder will turn the card situated on
its top towards the needle-board, and if catch, _z_, is brought into
contact with the lantern, the card hanging below the needle-board will
be the next in turn to be pushed towards the needles.
The entire length of the catches in the present illustration is 8 ins.,
allowing 5-1/4 ins. for the catch itself and 2-3/4 ins. for the part to
which it is fastened. Making this catch in two pieces is preferable to
the old style of one piece, because the moment of turning the cylinder
can be more easily regulated.