GB681259A - Improvements in and relating to screen printing or stencilling machine - Google Patents

Abstract

681,259. Stencilling-apparatus. THORNTON, A. A. (Shurley, F.). Nov. 9, 1950 [Aug. 9, 1949], No. 20687/49. Class 100 (ii). A screen printing machine comprises a screen or the like adapted to carry a design to be printed, means for carrying printing medium across said screen or the like to distribute it through permeable portions of said design, said means being adapted to reciprocate across said screen or the like to carry printing medium thereacross on each backward and forward movement and means for supporting simultaneously two articles to be printed, said supporting means being arranged to be reciprocated after each printing action in a direction at right angles to the reciprocation of the means for carrying printing medium across the screen or the like, so that whilst one article is being printed the article last printed is positioned so that it can be removed and replaced by the next article to be printed. The screen frame 12 is supported from an upper frame 23 which rests on rollers 38 in notches 40 of rods 36 slidable in bearings in brackets 30 on the machine frame 10. The screen 13 rests on a work-table 11 manually reciprocable laterally by means of rods 42 sliding in fixed bearings 43. The table 11 holds two articles to be printed, so that while one is in printing position below the screen, the other is to one side or the other of the screen and can be replaced. During printing, the article is held to the table by suction through holes communicating with a suction chamber formed by a plate 46 and communicating with a pump 52 through hose 48, valve 49, hose 50 and vacuum tank 51, the valve being open when the table is in printing position. A squeegee is supported from a cross-bar mounted by sleeves 19 on posts 20 secured to parallel tubes 28, and the pressure on the screen is adjustable by screws 25. The squeegee is reciprocated by a reversible electric motor 15 through chains 16 which slide the tubes 28 in bearings 29. At the end of each stroke, buffers 41 abut the rods 36, so that the legs 37 carrying the rollers 38 pass out of the notches 40 and the screen frame 12 is raised from the work. At the end of each stroke also, rollers 22 on carriages 21 on the squeegee cross-bar ride on to cams 32 on the frame 23 to temporarily raise the squeegee over the surplus point and lower it on the other side ready for the return stroke. The squeegee strokes are arrested by limit switches 54 operated by an arm 55 connected to the tubes 28. Switches 53 are operated by the table 11 so that the direction of movement of the squeegee depends on the position of the table. On loosening a screw 14a, the squeegee can be adjusted, lateral adjustment being performed manually, and vertical adjustment by a screw provided therefor.