Proof press system

Claim 1

A PROOF PRESS COMPRISING: A PRINTING CYLINDER HAVING END PORTIONS; HOLDING MEANS ROTATABLY TO HOLD SAID CYLINDER; A PROOF BELT TO WHICH A PROOF SHEET MAY BE ATTACHED; TWO ROTATABLE BELT SUPPORTING DRUMS PARALLEL TO EACH OTHER AND PARALLEL TO SAID CYLINDER UPON WHICH SAID BELT IS MOUNTED; BELT MOVING MEANS TO MOVE SAID DRUMS AND BELT TOWARD AND AWAY FROM SAID PRINTING CYLINDER FOR PRINTING ENGAGEMENET BETWEEN SAID PROOF SHEET AND SAID CYLINDER; SAID HOLDING MEANS INCLUDING TWO CYLINDER BEARING MEBERS RESPECTIVELY AT THE END PORTIONS OF SAID CYLINDER HAVING RELEASING AND RECEIVING MEANS FOR RELEASING AND CYLINDER FOR REMOVAL FROM SAID PRESS AND FOR RECEIVING A SECOND CYLINDER IN THE SAME POSITION AS SAID FIRST-NAMES CYLINDER; A CYLINDER ZERO MARK ON EACH OF SAID CYLINDERS; BELT ZEROING MEANS FOR LOCKING SAID BELT IN ZERO POSITION TO PREVENT ROTATION OF SAID BELT WHILE SAID FIRST-NAMED CYLINDER IS BEING REMOVED FROM SAID BEARING MEMBERS AND SAID SECOND CYLINDER IS BEING RECEIVED BY SAID BEARING MEMBERS; A CYLINDER ZERO MARK VIEWING TELESCOPE HAVING A ZERO MARK INDICATOR IN ITS VIEWING FIELD FOR VIEWING SAID CYLINDER ZERO MARKS AFTER SAID CYLINDERS HAVE BEEN RECEIVED BY SAID BEARING MEMBERS; AND CYLINDER ZEROING MEANS FOR ROTATABLY AND ENDWISE MOVING AND THEREAFTER HOLDING SAID CYLINDERS TO PLACE AND TO HOLD EACH OF SAID CYLINDERS IN ZERO POSITION WITH ITS RESPECTIVE ZERO MARK HELD IN THE ZERO POSITION OF SAID ZERO MARK INDICATOR UNTIL SAID BELT IS MOVED INTO CONTACT WITH SAID RESPECTIVE CYLINDER.