Patent GB-350063-A (GB)
Title: Improvements in stencilling apparatus
IPC: B41F15/08
Filed: 1930-03-15
Abstract: 350,063. Stencilprinting. JOHNSTON, C. L. and OWENS, E. A., 1504, Russ Building, San Francisco, U.S.A. March 15, 1930, No. 8464. [Classes 100 (i) and 100 (ii).] Stencilling-apparatus; st e nci l s; inking-apparatus.- Stencilling - apparatus comprises an oscillatable segmental platen carrying means for introducing the material to be printed between the platen and a reciprocatable stencil arranged at an angle to the horizontal and tangential to the platen, means for engaging the material to cause it to conform to the curved surface of the paten, and means for forcing paint through the stencil at the line of contact between the stencil and the platen. As shown, the stencil comprises a frame 55, which is covered with fabric 56 blocked out in the usual way, and is secured within a frame 25 suspended by arms integral with shoes 23 slidably mounted in inclined guide rails 21: a marginal portion of the fabric is permanently blocked out to provide paint-supporting surfaces. An impression segment 16 provided with counterweights 18 is oscillated by a rod 19 connected to a crank pin 12 on a rotary gear 8, and gears 26a on the segment 16 engage racks 26 on the frame 25 whereby the latter is reciprocated. Paint is forced through the stencil by a squeegee comprising a rubber blade 60 secured between plates 61 carried by plates 62 fixed to a bar 63 secured to arms 64 fixed to a shaft 65 adapted to be oscillated by an arm 69 connected by a rod 70 to a rocking arm 71 actuated by a cam 11 on a rotary shaft 6 whereby the blade 60 is raised on the upward stroke of the stencil. Springs 74 press the blade against the stencil, the pressure being varied by adjusting the blade relatively to the plates 62. In the raised position of the blade 60 a supply of paint is carried between the blade and a scoop 87 fixed to brackets 79 slidable on rods 80. When the blade is lowered to commence printing, cams on the lower end of the stencil frame 25 releases latches normally securing the scoop 78 in the position shown, whereupon springs arranged between the brackets 78 and brackets 81 move the scoop away from the blade so that the paint is deposited on the stencil. At the end of the downward stroke of the frame 25, lugs 91 thereon engage pins on the brackets 79, whereby the scoop is pushed back against the blade 60 so as to collect surplus paint and is held there by the latches. Feeding sheets.-At the end of the downstroke of the stencil, fingers 44 adjustably fixed to a shaft 47 are lowered into a position where they form front stops for a sheet, which is taken from a pile on a table 20 by an operator and is pushed forward during the inoperative stroke of the stencil. The shaft 47 is rocked by an arm 46 connected to a rod 45 reciprocated by a cam 11 on the shaft 6. Stationary fingers 97 coact with the members 44 to prevent the sheet from contacting with the segment 16 during the return stroke of the latter. Gripper mechanism.-The sheets are taken by a series of grippers 29 each of which has rack teeth engaging pinions on a shaft 33 to which is fixed a crank arm carrying a roller engaging a cam 37 rocked about a pivot 39 by a rod 40 fixed to an arm 41 oscillated by a cam on the shaft 6, whereby the grippers are raised to receive a sheet. Stationary cams 50 rock the shaft 33 to release the printed sheet, and a plate 51 adapted to strip the sheet from the segment 16 is rocked by one of three cams 13, 14, 15 on the gear 8 so that the sheet falls on to delivery tapes 53. Dust, removing.-Dust is removed from the surface of each sheet before it passes under the stencil by a flap wiper 103, Fig. 8, which extends transversely across the feed table 20 and is adjustably secured to the side frames of the machine. Specification 316,467, [Class 100 (ii), Printing processes &c.], is referred to.