Patent GB-377881-A (GB)
Title: Improvements relating to envelope making machines
IPC: B31B19/00
Filed: 1931-12-12
Abstract: 377,881. Envelope-making machines. CARLAW & SONS, Ltd., D. and CARLAW, D., 31, Finnieston Street, Glasgow. Dec. 12, 1931, No. 34492. [Class 94 (ii).] A machine for making window envelopes in which patches of transparent or translucent paper are used is characterized by an oscillating carrier which conveys each patch to a plunger, which may be the creasing plunger, the carrier being provided with suction means for retaining the patch thereon, means also being provided for cutting off the suction between the time when a patch is applied by the carrier to the plunger and the time when a new patch is received. The topmost one of a pile of envelope blanks 12, which may be of the shape shown in Fig. 11, having window apertures 92 cut therein, is lifted by the gummers which in descending have gummed the blank at 93. A pair of slides 13 move to the left, Fig. 1, and remove the blank from under the gummer by suction, carrying it to the right to position it below the creasing plunger 14, the blank being held on the creasing table by suction. A web of transparent material, cellophane, gelatine, &c. 15 is drawn from a longitudinally adjustable roll and fed by rolls 16, to a cutting block 17 a length being cut off by the knife 18 and immediately grasped, by suction, by the upper face of an oscillating carrier 19. The carrier moves to the left, pivoting about the shaft 21, and delivers the cut patch to the lower face of the creasing plunger 14. The plunger grasps the patch, by suction, and descends to press it into position on the blank when the patch is held to the blank by the adhesive strip 93. The carrying element 19 comprises a carrying face 19a to which lead a number of suction holes 24 from an internal space 22. Holes 26 lead from the front to the back of the carrier to help detachment of the patches. Grub screws 25 in holes 23 may be screwed inwardly or outwardly to determine which suction holes 24 shall be effective. The space 22 connects through a hollow arm 20 to a groove 28, the elements 29, 20, pressed together by a spring 32, acting as a slide valve to effect cut-off. A pipe 30 connects to a valve-box 50 in which are situated four spring-pressed valves 52 .. 55 each carrying a roller 57 actuated by a cam 56 on a cam-shaft 56a. The valve-box connects to a source of suction, e.g. a blower 64, which through the appropriate valves 52 .. 55 puts into suction either the carrier 19, the slides 13, the creasing table or the plunger 14. The outlet of the blower leads through an oil trap 68 and thence to nozzles 71, 72, the former blowing on the web 15 to ensure the correct positioning of a patch on the carrier and the latter blowing on the pile of blanks to effect easy separation of the same by the rising gummers. The plunger 14 consists of shaping plates 35, 35a, 37, 37a and a suction plate 36a with suction apertures 43, those which are to be rendered ineffective being stopped by grub screws. Holes 38 which pass from front to back of the shaping plates aid detachment of the envelope blank from the plunger. The actuating rod for the plunger may be spring- loaded to avoid damage. The brackets 45 carrying the patch roll 15, knife 18 and oscillating carrier 19 can be adjusted along the bed of the machine to allow of varying the position of the patch laterally of the blank, while alteration of the roll 15 in its bearings will allow for longitudinal adjustment on the blank. A jockey pulley 76 connected by a chain 73 with the driving means 74 of the cam-shaft 75 and of the carrier allows for the lateral adjustment of the patch positioning mechanism. A spring catch 85 connected by levers 86, 88 to the stopping mechanism of the machine ensures that the action valve 52 is maintained open so that a patch already on the carrier will not fall off on stopping the machine.