GB490361A - Improvements in or relating to printing telegraph apparatus - Google Patents

Abstract

490,361. Type - printing telegraphy. CREED & CO., Ltd., THOMPSON, A. E., and SALMON, R. D. Jan. 12, 1937, No. 973. [Class 40 (iii)] [Also in Group XVI] In a step-by-step receiver the type-wheel and printing-hammer are operated through a common coiled spring from a driving shaft rotated by a source of power, the hammer being preferably actuated when the type wheel stops in a desired position. A drum 5, Fig. 4, rotated by a source of power, has attached to it one end of a coiled spring 6, the other end being attached to a shaft 7 which rotates a planet pinion 16a between two gears 14a, 15a of a differential. One gear 14a drives, through gears 23, 24, Fig. 2, the type wheels 24a, 24b and a signal-controlled escapement 29, 30 mounted on a shaft 28. The other gear 15a of the differential drives, through gearing 33, 34, Fig. 1, a hammer-actuating cam 36 on a shaft 35 which by an escapement delay device, Figs. 3, 3a (not shown), is allowed to rotate a quarter of a revolution each time the shaft 28 stops at a position corresponding to a character to be printed. Rotation of the cam 36 raises a frame 63, Fig. 6, carrying two hammers 72 resiliently pivoted thereon at 71, one or other, according to the case signal received, being held down by a shield 66, Fig. 9, actuated through a lever 123 by levers 76; 77, Fig. 2, fixed to the type shaft 107. The shield 66 has in it two holes 66a, 66b so arranged that, according to the position of the shield, only one hammer can pass through its appropriate hole to strike the type wheel when both are thrown upwards by the frame 63. Also actuated by the lever 123 is a frame 121 having a slot 125 which is so positioned that the hammer not performing a printing operation can rebound through it. The Provisional Specification describes two alternative methods of releasing for rotation the shaft carrying the printing cam. In each case an escapement carried on the printing camshaft is released by a detent operated by a magnet through which a current is passed when the type wheel shaft comes to rest. In one method, Fig. 2 (Prov.) (not shown), the teeth of a wheel carried on the type shaft are in a circuit with two brushes and a slow acting relay. Only when the type shaft stops and the teeth no longer interrupt the circuit does the relay operate to close a circuit through the printing magnet. In the further method, contacts in the printing magnet circuit, Fig. 3 (Prov.) (not shown), are opened by a lever thrown away by the teeth of a wheel carried on the type shaft when the latter rotates. By a ratchet and wind vane device, the return movement of the lever is delayed so that only when the toothed wheel stops rotating is there time for it to return fully and close the contacts in the printing magnet circuit.