GB502521A - Improvements in or relating to transmitters for step-by-step telegraph systems - Google Patents

Abstract

502,521. Type printing telegraphy. CREED & CO., Ltd., THOMPSON, A. E., and SALMON, R. D. Sept. 17, 1937, No. 16773/38. Divided out of 490,404. [Class 40 (iii)] A transmitter for step-by-step type-printing telegraphy comprises means, actuated by the depression of a key, for releasing a shaft for rotation to a position dependent on the particular key depressed, means for locking the keyboard during transmission of impulses, and means for providing a predetermined delay between the actuation of the locking means and the release of the said shaft. By means described in detail in Specification 490,404, the depression of a key causes the keyboard to be locked and the release for one revolution of a cam 54, Fig. 3. Towards the end of this revolution the cam 54 depresses one end 55 of a pivoted lever to the other arm 56 of which is attached a detent 57 which thus rises and is held by a detent 61. The detent 57 disengages its cam 17 and so allows the rotation of the transmitting contact cams which are mounted on the same shaft as the detent cam 17, A number of impulses is transmitted until a shaft carrying a gear-wheel 29, driven from a gear 20 on the transmitting shaft, has rotated to a position characteristic of the key depressed. The keyboard is then unlocked by means described with reference to the parent case and the latch 61 is released so as to bring the detent 57 into engagement with its cam 17. The partial revolution through which the cam 54 rotates before releasing the transmitting shaft by means of the detent 57 provides the predetermined delay and ensures a definite pause between successive series of impulses.