Machine for continuously corrugating thermoplastic sheets

摘要

954,471. Corrugating thermoplastic sheets. LAVORAZIONE MATERIE PLASTICHE L.M.P. S.p.A. March 8, 1963 [March 10, 1962], No. 9265/63. Heading B5A. In a machine for corrugating thermoplastic sheets having undercuts the shaping dies for the undercuts in addition to being adapted to be drawn together in a direction perpendicular to the sheet are also displaceable relative to a mutually interlocked position, the contact between the dies and the sheet being less than the amount of transverse draw on the sheet during corrugating, means being provided for maintaining the sheet transversely stretched during corrugating. The machine comprises upper and lower guides 40, 41 of which the upper one 40 is movable vertically by pneumatic means. Each girder carries five sets of identical dies. In each set lower girder 41 has rigidly connected to it a hollow member 51 having an L-shaped hull 52, the outer surface 5211 of which is designed not to contact a sheet 20, and a member 56 having a hull 57 the free horizontal flange of which completely fills a loop 16 formed thereby. These two dies have cooperating therewith three dies carried by the upper girder 40 through a common supporting block 58, viz. a tubular member 59 swingably mounted on block 58 and carrying an L-shaped hull to co-operate with hull 52; a stationary member 62 having a hull 63 which fits into the clearance between hulls 60 and 57 so as to loop the sheet about hull 57 and also deflect it downwardly from the bottom surface of hull 60; a tubular member 64 swingably mounted on block 58 and having a hull 65 similar in profile to hull 60. Members 59 and 64 are swingable on arms 61, 66 moved by fluid pressure devices 75, 76 having means for adjusting the stroke. The hull 60 interlocks loosely with hull 52 to form a channelled shaped portion 15, and the hull 65 with hull 57 to form a loop 16. Two further dies of a triangular cross-section 67a, 68a both rigidly attached to their respective supporting girders co-operate to form a step 14 in the sheet. The dies are water-cooled. In operation the upper girder 40 is raised so that a sheet 20 may be fed into the machine. This girder is then slowly lowered so that the edges of the sheet are gripped by shoes (not shown) whereupon the upper dies come into contact with sheet 20 and the swinging arms 61, 61 are slowly moved so that the movable dies are angularly displaced and brought into their operative positions. Specification 825,392 is referred to.