Sheet stack lifting drive for offset printing machine with function checking of signal source associated with drive motor shaft without requiring movement of sheet stack carrier plate

摘要

The sheet stack lifting drive has a drive motor (4) and an intermediate gearing (3) for vertical movement of a sheet stack carrier plate (2), with a lifting drive control (9) responding to signals provided by a signal source (7) coupled to the shaft of the drive motor, for controlling the motor drive control (6). The signal source can be checked with the sheet stack carrier plate at a standstill by supplying signals causing movement of the drive motor shaft, with verification of the signal source signals by the lifting drive control.