GB1482379A - Exertion of compressive forces on moving webs - Google Patents

Abstract

1482379 Calendering paper BRUDERHAUS MASCHINEN GmbH 12 Aug 1975 [24 Aug 1974] 33468/75 Heading D2A A calender e.g. for a paper web having at least one nip defined by a hard roll 2 and a resilient roll 3, and provided with means for applying an adjustable lifting force to the bearings of at least one of the rolls 2, 3, e.g. for relieving the roll of the weight of its bearings, is provided with means for temporarily increasing the lifting force in order to reduce the compressive force between the rolls 2, 3 to zero but without separating the rolls from the web, thereby allowing passage of joints in the web through the calender without damage. As shown the bearing cheeks 4 of all but the top and bottom rolls of the supercalender 1 have bosses 6 overlying nuts 17 threaded on suspension spindles 7 which pass through the bosses 6. As shown in Fig. 2 each nut 17 supports a housing 18 having two diametrically opposed hydraulic cylinders 23 in which pistons 24 work to apply lifting forces to the underside of the overlying boss 6. The cylinders 23 are connectible to two sources of different pressure whereby the usual or the temporarily increased lifting force may be selectively applied to the boss 6. Alternatively, as in Fig. 5 (not shown) each housing 18 may have four piston and cylinder devices, two being supplied with pressure to apply the usual lifting force to the boss 6 and all four being supplied with pressure from the same source to apply the increased lifting force. The top and bottom rolls may have separate piston/cylinder devices 14, 10 for separation of the rolls 2, 3.