perforating machine
A machine used for perforating paper. Two types of
perforating machines are in general use: 1) the
vertical, or flat-bed perforator, in which the
punches and dies are set in a straight line, with
the punches set in a moving bar and the dies in
the surface of the table. Several sheets may be
fed at one time between the punches and dies
against adjustable guides. When the machine is
activated, the bar descends and punches a series
of holes in the paper. The punches are adjustable
so that some may be removed when the holes are to
be punched only part way across the sheet; and 2)
rotary perforators, which are capable of punching
round holes, slots, or slits. The punches and dies
are mounted on discs that revolve against each
other, the paper being fed between them, with one
edge against a guide. This type may be set to
perforate struck lines as well. Some types of
perforators raise the punches for struck lines,
while others drop the dies; however, in either
case, the punches d o not enter the dies, so the
sheets are left unperforated. This movement of
dies or punches is synchronized with the opening
of a paper gate so that the perforating will start
at the desired point. The same result may be
obtained on other machines by removing some of the
punches. Rotary perforators can accommodate
several perforating heads which are adjustable
laterally on the spindles to change the spacing
between the lines of perforations. The minimum
spacing varies with different makes of machines.
The angle perforator can punch in both directions
at one feeding. This machine is actually a
combination of two rotary perforators at right
angles to each other, with feed rollers to carry
the sheets of paper from one set of perforating
heads to the other.
By means of special attachments, most rotary
perforators can also perform other operations,
such as scoring, crimping, and slitting. (320 , 339 )
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