| 摘要 |
PURPOSE:To continuously form a heat shrinkable sheet out of a preformed piece on continuous form by a structure wherein pairs of chucking blocks, each of which grasps one of both side parts of a softened preformed piece so as to pull the piece toward both sides of it, are provided so as to be freely accessible and separable. CONSTITUTION:When the tip of a preformed piece A, which has been brought into softened state by heating in advance, is fed nearly horizontally from the rear of a stretching part 4 between both caterpillar treads 1 and 1, first, clamps 9, which approach the rear position of the stretching part 4, close so as to grasp both side edge parts of the preformed piece A between both pairs of chucking blocks 11 and 12. Secondly, when the clamps 9... in clamped state approach the stretching part 4, the interval W between the treads facing each other of both revolving courses gradually widens and consequently the preformed piece A grasped with the clamps is stretched widthwise while being carried in the longitudinal direction. When the clamps 9... approach the parallel part 5, a cooling mechanism 8 cools the preformed piece A just after being stretched from above and below. Because, by said cooling action, the preformed piece A after the stretching is hardened under the state that both side edge parts of the piece A are held by the clamps, the waviness and the like, which tend to develop in a sheet after the clamping is released, is hard to occur. |
