Patent GB-702402-A (GB)
Title: A device for printing on a flat or slightly dished circular surface by the silk screen process
IPC: B41F15/08
Filed: 1951-03-28
Abstract: 702,402. Stencilling apparatus; printing pro. cesses. DUBUIT, L. G. March 28, 1951 [Oct. 4, 1950], No. 7241/51. Class 100 (2) Stencilling apparatus.-Apparatus for printing on a flat circular surface by the silk screen process comprises a support 111 (Fig. 4) for a horizontal stencil 113, a support 18 for an article 19 (Fig. 1) to be printed, the article being brought into contact with the lower surface of the stencil, a flexible squeegee 33 co-operating with the upper surface of the stencil 113 and the length of which is substantially equal to the diameter of the surface to be printed, the squeegee 33 being supported by a horizontally flexible member 29, and guiding members 64, 64a being provided for bringing the squeegee to fit an arc of circle corresponding to a portion of the periphery of the surface to be printed, one end of the squeegee being held fast while the other end is constrained to describe an arc of circle corresponding to the periphery of the surface to be printed so as to pass to a position which is symmetrical to the starting position of the squeegee with respect to the diameter of the surface to be printed which passes beneath the end of the squeegee which is held fast. The apparatus comprises a base 1 on which are fastened columns 3, 4, having supports 5, 6 mounted thereon. The support 6 has slidably mounted thereon a square shaft 22 to the lower end of which is secured a crank 23 to which the fixed end of the squeegee supporting member 29, consisting of chain links, is secured. Rotatably mounted in the square shaft 22 is a shaft 26 carrying at its lower end a crank 27 to which is fixed the other end of the squeegee supporting member 29. Axial movement of the shaft 22 is effected by a pivoted lever 67 controlled by a crown cam 70 fixed on a shaft 7 driven by a motor 2 on the base 1. Slidably mounted between the base 1 and the support 5 by means of a fixed sleeve 16 in the base and slidable sleeve 17 in the support 5, is a shaft 15, movement being effected by a pivoted lever 11 and a second crown cam 9 mounted on the shaft 7. The shaft 15 carries at its upper end the support 18 on which is carried the article 19, e.g. a plate, to be printed. Also mounted on the shaft 7 are cams 61, 61a co-operating with cam follower rollers 60, 60a on a lever 59, in turn fixed to a sleeve 56 rotatably mounted on the column 3. The lever 59 includes an arm 53 which, when rotated, causes oscillation of the guiding member 64, 64a about a vertical column 21, fixed between the supports 5 and 6, through linkage 49 to 52. The stencil 113 is held in the support 111, Fig. 5 (not shown), which is provided with a pair of lateral ears 112 bolted on arms 110 in turn fastened on the columns 4. In operation, as the shaft 7 is rotated the crown cam 9 and lever 11 causes the shaft 15 to be raised together with the support 18, the relative movement which ensues between the support 18 and a sleeve 17 causing levers 79, 81 pivoted on the support 18 to rock and correctly centre the plate 19 to be printed. At the same time crown cam 70 and lever 67 operate to lower the square shaft 22 carrying the squeegee 33 into operative relationship with the plate 19 and stencil. Further rotation of the shaft 7 causes cams 61, 61a to cause oscillation of the guide members 64, 64a so that the squeegee is swept over the stencil, cams 9 and 70 then causing shaft 15 to be lowered and shaft 22 to be raised. Tripping arrangements.-In the event of no plate being placed on the support during operation the levers 79, 81 having no plate to bear against rotate further than normally and thereby permit greater relative movement between the support 18 and the sleeve 17 in turn permitting a lever 87 to rotate anticlockwise. Rotation of the lever 87 causes clockwise rotation of a lever 92 and thereby, through a rod 98 slidable in the vertical column 21, lever 100 and link 103, causes a lever 104 carrying a nose 107 to be positioned under a stop 108 on the lever 67 to prevent operation of lever 67 to lower the squeegee apparatus.