Control for paper cutting apparatus

A control mechanism for use in conjunction with a paper cutting machine having a table for supporting a pile of sheets to be cut, cutting means for cutting said pile of sheets and means for operating the cutting means, a back gauge mounted for movement along the table so as to determine cutting positions of the pile and to stop it in a position for cutting, mechanical drive means including a worm gear operable manually or by power drive for moving the back gauge along the table in either direction, comprising,

• signalling means for signalling the movements of the back gauge including an optical disc mounted on said worm gear,
• a controller responsive to said signalling means and including a digital computer and means for resetting the controller when the back gauge moves to a key position,
• a keyboard connected to the computer,
• the optical disc having a series of circumferentially spaced-apart radial indicia, a pair of companion photosensors mounted in a position to sense the radial indicia on the optical disc, whereby its movement in one direction produces in the controller one wave form and its movement in the other direction produces another wave form,
• the controller being electrically connected to the signalling means and the computer converting the wave forms into direction and distance corresponding to the travel of the back gauge and provided with means to (a) accept and store such information and (b) to accept program information from the keyboard and to store and process this information and retrieve it on command from the keyboard or the cutting means and to provide output to control said mechanical drive means, and including,
• means connected to the computer mechanism to control the drive means to move the back gauge in either direction and stop the gauge in response to command from the computer mechanism,
• the keyboard operating the controller to register and store a plurality of programs on separate channels, each program made up of a number of sequential positions of the back gauge,
• means within the computer responsive to the keyboard or the cutting means for selecting a desired channel and retrieving a program and applying it to control the drive means to cause movement of the back gauge and a procedure for stopping it according to that program,
• digital display means connected to the computer mechanism for visually displaying the action of the controller, including the position of the back gauge and the cutting sequency programs.