GB146254A - A duplicating apparatus in which the printing is effected by the aid of a stencil - Google Patents

Abstract

146,254. Breuer, A., and Heyn, A. March 14, 1919, [Convention date]. Stencilling; tripping-arrangements.-In duplicating apparatus in which a stencil is supported by feed bands engaging a pair of cylinders the upper one of which is spring supported and against the other a pressure roller is periodically pressed and retracted by cams, the springs are independently adjustable, and the cams are mounted on the axis of the lower cylinder. Projections on the bands engage depressions in the cylinders, and the stencil is carried by a support in two parts adapted to be moved laterally apart. Cylinders G and H, Fig. 1, are connected by bands J carrying a stencil, and paper is pressed against the lower cylinder H by a roller g. The spindle K of the upper cylinder G is mounted in bolts b slidable vertically in guides a having threaded engagement with hollow screws d in which are mounted springs c bearing against the ends of the bolts b so as normally to place the bands J under tension. The tension of each band is therefore independently adjustable, and the cylinder G and bands J may be released for replacement &c. by withdrawing the screw d. The roller g is supported in a slot f in a plate c bv ono end of a bell-crank lever h pivoted to the plate e, the other end of which is forced by a spring i into engagement with a stop k by means of an adjustable screw r. The plate e is guided in a vertical direction by arms l and m pivoted at Q and R to the frame P of the machine, and is raised or lowered by a bar n engaging a roller o on the plate e and guided by links n<1> and n<2> pivoted to the frame P and to the bar n, which is connected to a slotted lever p pivoted at p<5> to the frame P and operated by a cam disk v engaging a roller p<3> to lower the plate e, which is raised by a similar lever p<1> connected by a cross-bar p<2> to the lever p and operated independently by a cam disk v<1>. The spring i is not extended until the roller g engages the cylinder H, and further raising of the plate e forces the roller g down into the slot f. The lever p<1> is then approximately vertical so that the mechanical advantage is high and a small pressure only is required to press the roller g into printing engagement. The bands J are provided at equal distances apart with rivets s the heads of which are adapted to engage corresponding recesses in the edges of the cylinders G and H whereby the bands J are reinforced and a silent drive is ensured. Two oppositely disposed rivets s are replaced by screws to which a cross-bar u, Fig. 3, is attached by nuts t. Mounted on the bar u are two slide bars v and v<1> provided with projections w engaging slots N in the upper edge L of the stencil M and adapted to be separated by rotating a disk having slots engaging pins v<2> on the bars or by moving the bar v<1> to the right. The slots N may be of the form shown in Fig. 7, so that the projections w are retained in alinement.