GB854261A - Improvements in high speed printing mechanism - Google Patents

Abstract

854,261. Selective printing. ELLIOTT BROS. (LONDON) Ltd. March 12, 1957 [March 14, 1956], No. 7958/56. Class 100(4) Type-wheel machines; hammer impression arrangements. In a high-speed printing machine for use with electronic computors and employing a continuously rotating assembly of type wheels 1, the hammer mechanism for each column of type, comprises a sliding hammer 4 operated by the nose 10 of an actuator 6 having a V-shaped lug 9, which when the actuator 6 is released by a latch 7, engages in the notched periphery of a cam 2 rotating synchronously with the type-drum 1. Operation of the hammer mechanism is initiated by appropriately timed energisation of an electromagnet 13 whose armature 14, dog element 15, and latch 7 allows the actuator to engage the cam 2 under tension of spring 21. A cam tooth 3 thrusts the lug 9 and the actuator 6 in a pivotal movement about trunnion 20 and just before the hammer makes the impression the nose 10 dips below the hammer 4 to allow it to rebound, assisted by.spring 19. The rocker 16 biases the actuator in latched position. In an alternative arrangement the actuator 6, the latch 7 and the electromagnet 13 may be duplicated to operate the same hammer 4 to double the frequency of operation. A further embodiment (Fig. 2, not shown) the latch -is formed as a straight lever and cooperates with a rocker which operates on a second cam wheel. This construction enables the electromagnets to be at right angles to those in Fig. 1. Instead of the actuator having a sliding and pivotal action about the trunnion 20, the hammer 4 may have a small pivotal as well as a sliding action and the actuator operates about a fixed axis. There is a blank space on the type-wheels equivalent to ten characters and a corresponding space on the cam 2 which prevents any printing as the paper is being fed.