Blanket cylinder providing for ready mounting and dismounting of a blanket

摘要

A blanket cylinder for use in offset lithography in combination with a blanket assembly (T) including a blanket (28) and a carrier sheet (C) therefor. The carrier sheet of the blanket assembly has a major portion (20) to which the blanket is attached, a first flange (21) at an acute angle to the major portion, a second flange (27) at an obtuse angle to the major portion and a rim (23) at an acute angle to the second flange. The blanket cylinder comprises a cylinder assembly (B) having formed therein an undercut groove (7) with an entrance slot (6) bounded by and between a first (24) and a second (25) longitudinal edge, the first longitudinal edge being cross-sectionally shaped to be engaged by the first flange (21) of the carrier sheet (C), and a retainer spindle (12) mounted in the undercut groove in the cylinder assembly for bidirectional rotation therein.;In order to hold the blanket assembly (T) closely wrapped around the cylinder assembly (B), the retainer spindle (12) is cross-sectionally shaped to include a pull-in hook (16) for engaging the rim (23) of the carrier sheet (C) in order to pull the second flange (27) thereof into the undercut groove (7) with the rotation of the retainer spindle in a first direction, and a push-out ledge (28) for abutment against the rim (23) of the carrier sheet in order to push the second flange (27) out the undercut groove with the rotation of the retainer spindle in a second direction. The retainer spindle (12) is biased by a pair of torsion springs (17, 18) to turn in the first direction.