GB673844A - Improvements relating to stencilling machines - Google Patents

Abstract

673,844. Stencilling-apparatus. McCORMICK, W. P. May 2, 1949, No. 11603/49. Class 100 (ii). In a stencilling machine wherein a squeegee is reciprocated mechanically over a gauze or silk screen and during the return stroke is pivoted clear of the screen, and the screen pivoted upwards clear of the printing table to allow removal of the stencilled sheet, an inking device comprises an ink feed roller rotatable against a scraper blade so that ink is transferred thereto, the blade being movable down on to the screen during the upward pivotal movement of the latter to transfer the ink from the blade to the screen. The stencilling machine is of the general construction described in Specification 673,815, an electric motor A driving a shaft 7 through gears 3, 4, 6, 5, whereby the squeegee carriers 9 are reciprocated along guide bars 11 by crank arms 8 and rods 10. The bars 11 carry the screen frame 12 and are pivotally mounted on the shaft 7. The screen frame is pivoted upwards during the return stroke of the squeegee by a cam 15 acting on a lever 16 rigidly connected to the guide bars. Mounted in brackets 18 is an ink feed roller 17 having flanges 22 and rotated continuously by chain and sprocket drive from the gear 6. The roller 17, flanges 22, brackets 18 and a sloping duct blade 19 constitute a container for ink, which is transferred to the surface 24 of a steel blade 23 bevelled on its rear face and in contact with the roller, which makes two or three clockwise revolutions for each revolution of the shaft 7. The blade 23 is mounted between the ends of the arms 25 of two bell-cranks 25, 26 pivotally mounted in the brackets 18 at 26A. As the screen frame 12 is raised, the blade 23 is lowered, by a cam 27 acting on the arms 26 of the bellcranks, into contact at an acute angle with the screen 13 before the latter has reached its uppermost position, and when the squeegee is halfway on its return stroke, and transfers the ink to the screen. The blade is raised clear of the squeegee as the latter continues its return stroke.