Relative angular position adjustment apparatus for a driven body of

Abstract

To provide for fine-adjustment of the relative angular position of a driven body of rotation, such as a plate cylinder (1) of a printing machine, and having a driven shaft (21, 41) with respect to a driving shaft (9, 40), an axially shiftable intermediate shaft portion (14, 53) is positioned between the driving shaft (9, 40) and the driven shaft (21, 41) and the body of rotation, respectively. An elastic coupling structure (16, 24; 55, 57), for example a composite stacked leaf spring, and having the characteristic of being circumferentially stiff but axially flexible, couples the intermediate shaft, for axially shifting movement, between the respective shafts. Preferably, two such elastic coupling structures are provided. The intermediate shaft is axially shifted in response to changes in transmitted torque by a drive train from a drive motor (4) to the printing cylinder (1) under control of a torque responsive element, such as a strain gauge (37) coupled to a servo system which axially shifts the intermediate shaft portion, or by a torsion sleeve (46) which can twist in response to transmitted torque, the change in axial dimension upon twist of the torsion sleeve being transmitted through a hollow shaft to the intermediate shaft portion. Thus, circumferential register of the driven body of rotation, for example the printing machine cylinder (1) can be controlled in dependence on transmitted torque and register errors due to loading on the printing cylinder can be eliminated. The system is also applicable to other apparatus structures, such as rotary punches and the like.