Abstract: A die-cutting machine comprises two form-carrying rolls (10,12) operable in timed relation to produce alternate blanks, with minimum wastage between the blanks, from a web fed at constant speed by a conventional feed mechanism (14). The rolls (10,12) are driven by computer-controlled variable speed high impulse duty D.C. motors (28,30) supplied with electrical power from thyristor controlled power supplies (36,38). Sensors (18, 24, 26) provide feedback signals representing web speed and instantaneous roll positions and speeds to the programmable computer units (32,34). The use of the computer-controlled D.C. motors avoids backlash problems in previously proposed mechanical drives and allows greater flexibility, especially in maintaining registration between the rolls and preprinted areas on the web. A flywheel arrangement is employed to reduce the loading on the motors during large variations in roll speed.

Abstract: Treatment apparatus for continuous web for producing diecut blanks (for example) has two sets of treatment rolls and the speed of these is adjusted so that although driven at web speed during the treatment portion of each cycle they are accelerated and retarded (or vice versa) during the non-treatment portion of each cycle so as to synchronize the treatment forms on the rolls with the required web areas and avoid wastage. The speed variation is by control of the drive motors for the rolls, but using roll-carried cams connected to gas springs so that energy can be absorbed during retardation and released during acceleration to supplement the motors and thus enable smaller motors to be used.

Abstract: A rotary die-cutter is arranged for front or rear edge stripping by providing spring fingers which are moved rearwardly, relative to the rotation of the impression cylinder, to engage the front edge scrap and clamp it on the roll, for movement with the roll out of the plane of feed of the web while the remainder of the blank is fed onwardly into said plane.

Abstract: Stripping apparatus to remove scrap around die cut blanks in a web comprises a roll pair through which the web is passed, one roll carrying spikes to impale the scrap pieces and the other roll carrying abutments to contact the scrap pieces on the opposite side to the spikes. According to the invention the abutments are retractable, so that effectively the scrap piece is pinched between the spike and abutment shortly before the nip of the rolls. FIG. 1 illustrates the preferred arrangement.

Abstract: A die-cutting machine comprises two form-carrying rolls (10,12) operable in timed relation to produce alternate blanks, with minimum wastage between the blanks, from a web fed at constant speed by a conventional feed mechanism (14). The rolls (10,12) are driven by computer-controlled variable speed high impulse duty D.C. motors (28, 30) supplied with electrical power from thyristor controlled power supplies (36,38). Sensors (18, 24, 26) provide feedback signals representing web speed and instantaneous roll positions and speeds to the programmable computer units (32, 34). The use of the computer-controlled D.C. motors avoids backlash problems in previously proposed mechanical drives and allows greater flexibility, especially in maintaining registration between the rolls and preprinted areas on the web. A flywheel arrangement is employed to reduce the loading on the motors during large variations in roll speed.

Abstract: The invention provides a feeder having two stacks which are top fed by reciprocating suction boxes, the stacks feeding alternately and a belt being used to transfer blanks from the rear stack.

Abstract: A web is reciprocated through a treatment roll pair so that a succession of treated areas is formed on the web, one of said areas being formed on each forward movement, and the reverse movements serving to enable re-positioning of the web and avoiding waste between each two said areas. Two pairs of feed rolls are provided, one pair for forward feed and one pair for reverse feed. Each feed roll pair is engageable with and releasable from the web by having separable rolls. The feed rolls are all driven from a common camshaft.

Abstract: Apparatus for die-cutting preprinted web has an adjustable web feed mechanism which is controlled by circuitry for detecting mis-registration between die-cutting and the preprinted portions of the web, of which the following is a specification.