GB821152A - Improvements in and relating to apparatus for the deposition of viscous liquid materials - Google Patents

Abstract

<PICT:0821152/III/1> <PICT:0821152/III/2> In apparatus for depositing thin layers of paint, ink and other viscous materials in accurately-defined patches on surfaces, of the kind comprising a matrix having one or more shallow cavities in its operative face, conduits leading through the matrix for the introduction of coating-material to the cavities which are closed by the surface to be coated, and means for controlling relative movement between the matrix and the said surface, the separation of the matric and the surface, after coating, takes place in three phases, the first being of small predetermined extent at high speed, the second at low or nil speed, and the third at a speed higher than that of the second phase and of greater extent than the first. The second phase allows time for the breakage of most or all of the small strings of coating-material formed between the matrix and the coated surface. As shown, the matrix 5 is fixed to a frame structure comprising base 2, posts 3, and an open top frame 4, the matric having on its under side a number of shallow cavities 6 bounded by ridges 7 and connected, by tubes 9, to pumps 12 which supply coating-material from reservoirs 14. Beneath the matrix 5 is a platen 18 carried by the ram 17 of a vertical hydraulic press 15. The direction of movement of the ram is determined by the admission of hydraulic fluid, supplied through a conduit 29, to the spaces above or below the piston 28, under the control of a double-acting valve comprising a body 20 and a spool 21 carrying lands 22,23, small movements of which mask or unmask the ports 24,25 of the press. The valve spool 21 is operated by being pivotally connected at 39 to a lever 35, one end of which is pivoted to a collar 38 on the ram 17 and the other end carrying a cam follower 34 which is held up to a cam 33 by a spring 54. The cam 33 is mounted on a shaft 32 driven at constant speed by an electric motor, and is suitably profiled to give the required rates of opening of the ram. Also carried by the shaft 32 is a cam 40 which operates the plungers of the pumps 12 through a rod 42, and a lever 45 which acts on a plate 47, mounted for vertical movement on pins 48. Sheets or cards to be coated are fed singly and in succession from a lay board 50 by feeder bands 51, which are driven at intervals from the shaft 32 or a part driven in synchronism therewith, brought to rest over the platen 18, coated by closure of the press and operation of the pumps 12, and removed, after opening of the press in three phases as described. They are then received by bands 52 and usually introduced into a drying oven 53.