| 摘要 |
<p>Pairs of prefolding and pressure rollers (3, 4 and 8, 9, respectively) of identical diameters are successively arranged for rotation in a machine frame (1). A first pressure roller (8) is stationarily mounted to machine frame (1) for rotation whereas the first prefolding roller (3) associated with this side is rotatably mounted on spring-biased support members (10) which are slidable normal to the folding direction (A). The second prefolding roller (4) is mounted for rotation in bearings (14) provided at the two ends of the roller, said bearings being installed in lever arms (15) pivotally mounted to machine frame (1). Connecting arms (21) are hinged to the bearings (14) to support the second pressure roller (9) for rotation in bearings (13). The connecting arms (21) are biased by springs (18) such that during feed-in of a prefolded stack into the nip of pressure rollers (8, 9) the springs (18) are biased by pivoting the connecting arms (21) in a way that the pressure of the second prefolding roller (4) is increased and, thus, the frictional forces exerted on the stack are enhanced. <IMAGE></p> |
