GB1228439A - - Google Patents

Abstract

1,228,439. Selective printing. SCM CORP. 7 Aug., 1968 [14 Aug., 1967], No. 37676/68. Heading B6F. A print hammer assembly 13 comprises a plate 28 bearing a comb assembly 30 on which a plurality of print hammers 35, e.g. four, are coaxially pivotally mounted, the plate 28 also bearing an equal number of hammer actuating mechanisms 49-52, each of which coacts with a differently located one of a plurality of actuating levers 41-44 on a respective print hammer 35. Each actuating mechanism comprises an electromagnet having a coil 55 and a pole face 54<SP>1</SP> acting on an armature pivoted at 58 and including an arm 45, 46, 47 or 48 bent to engage the respective actuating lever of the corresponding print hammer 35. The ends 45<SP>1</SP>-48<SP>1</SP> of the arms 45-48, and the levers 41-44, are convex so that during actuation of a hammer, rolling contact therebetween is achieved. A hammer is actuated by energization of an electromagnet in response to electrical signals supplied by a printed circuit 62, thereby causing clockwise rotation of an armature and hence an arm 45- 48 and effecting anti-clockwise rotation of a print hammer 35 against a spring 38, so that an impression is made on a sheet R<SP>1</SP> through a simultaneously lifted ink ribbon R by means of a type drum 10 or a type band (not shown). A plurality of assemblies 13 may extend along the print line (Fig. 1, not shown), or a single assembly may travel therealong. Where a plurality of assemblies is provided, each is releaseably fastened in a groove (74, Fig. 1) of a frame (18) by a clamp element (72), the assembly being held in the groove by a spring-urged ball 76, Fig. 2. Adjustable stops 60 define the initial positions of the hammers 35.