Abstract: A web is being pulled off a supply roll nearing exhaustion. As the supply roll becomes exhausted, the web being pulled off is severed, and the trailing end of the severed web is glued to the periphery of a fresh web supply roll. Before the severing and gluing operation occurs, the peripheral speed of the fresh web supply roll must be brought up to coincidence with the travel speed of the web being pulled. An accelerator roller driven by a motor rolls upon the fresh supply roll, accelerating it up to speed. When the fresh roll reaches the predetermined speed, the severing and gluing unit is enabled for subsequent synchronized activation. The acceleration of the fresh roll is monitored indirectly by a transducer coupled to the accelerator roller. When the desired speed is reached, a time delay is allowed to elapse before the motor is shut off, causing the desired speed to be exceeded. As the fresh roll then decelerates it again reaches this speed.

Abstract: A plurality of rollers each carried on an element pivoted on a support swing back and forth into engagement with respective continuously driven rollers to pinch a sheet delivered between the rollers by means of a vacuum lifter and advance it along a path. A motor on each support can vary the position of the respective movable roller relative to the fixed roller and the pivotal element is insulated from the support but abuts conductively thereagainst in a rest position. A controller connected between the support and the element detects abutment of the two contact surfaces which function as switches and operates a control system that can vary the spacing between each pair of rollers in accordance with the thickness of the sheet being fed to it. A too thick a sheet will push the rollers apart prematurely and open the switch and a too thin sheet will not push them apart before the vacuum lifter releases it.

Abstract: The stack of sheets is moved towards the distributor at a control velocity corresponding to the distributor operation. If the stack in the operative vicinity of the distributor becomes too low, indicating too slow a stack advance, a mechanical sensor sensing the position of the top of the stack rotates to a position interrupting the signal furnished by the first and second inductive input signal generator. The interruption of the signal results in the furnishing of a second sensor output signal which, at a time determined by a synchronizing signal sets a monostable multivibrator whose output then energizes a relay which in turn applies voltage to a winding of a servomotor moving the arm of a potentiometer in a direction for increasing the speed of advance of the stack.