GB907624A - Improved apparatus for the production of printing plates from thermoplastic materials - Google Patents

Abstract

907,624. Printing surfaces. MASCHINENFABRIK AUGSBURG-NURNBERG A.G. Oct. 30, 1959 [Oct. 31, 1958], No. 37006/59. Class 100 (2). Apparatus for the production of printing plates from thermoplastic material comprises an embossing press having heated upper and lower platens 3, 2, a cooling press having a lower platen 4 level with that of the embossing press and an upper platen 5 movable by a fluidoperated piston 13 acting on an eccentric shaft 9, and conveyer means for moving a printing plate between presses. A piece of thermoplastic material 18 and a matrix 17 are placed in superimposed relationship on the platen 2 and the platen 3 which is operated by hydraulic or toggle means is moved down so as to press the matrix into the thermoplastic material. The platen 3 is subsequently raised and the assembly of matrix and printing plate is moved quickly on to the platen 4 by means of endless chains 23 mounted on wheels 25, 26 and carrying dogs 24 which engage a supporting plate 39 for the assembly 17, 18. The chains 23 are actuated by a hand-crank 28 and the dogs 24 are disengaged from the plate 39 as soon as the assembly is correctly positioned on the platen 4. The platens 4, 5 are cooled and the upper platen 5 is connected to the eccentric shaft 9 by connecting rods 6. A lever 11 secured to the shaft 9 is connected by a link 12 to the piston 13 which is slidable in a cylinder 14. When compressed air is introduced into the bottom of the cylinder 14 the shaft 9 is rotated and the platen 5 moves downwards to bear on the matrix and plate assembly 17a, 18a while it is being cooled. When compressed air is released from the cylinder 14 the piston 13 descends under its own weight and raises the platen 5. The rods 6 are pivotally connected to the platen 5 by eccentric bearings 19 which can be rotated by a handle 20 so as to vary the width of the opening between the upper and lower platens. Before being put in the embossing press the matrix and thermoplastic material are preheated under slight pressure between heated platens 21, 22, of which the upper platen is pivotally secured to the lower. When an assembly 17b, 18b of matrix and material is positioned on the platen 21 the platen 22 is swung down into engagement therewith by hand, pressure being applied by means of co-operating hooks 29, 30 mounted on the platen 22 and a shaft 32 respectively. The shaft 32 is eccentrically mounted and is rotatable by means of a pneumatic piston and cylinder arrangement 36, 37 whereby the hooks 30 are first moved into engagement with the hooks 29 and then pull downwards on the latter hooks.