Patent GB-437303-A (GB)
Abstract: 437,303. Type -printing telegraphy. FINCH, W. G. H., 315, Riverside Drive, New York, U.S.A. April 28, 1934, No. 12897. Convention date, April 28, 1933. [Class 40 (iii)] A printing-telegraph receiver is operable in response to signal code combinations each of which consists of a plurality of groups of impulse conditions, each group consisting of a combination of working and spacing conditions which are preferably constituted by long and short impulses respectively. The first group of the signal combination is preceded by a prolonged synchronizing impulse which energizes a relay 12 and a slow operating relay 12<1> of low resistance, when an arm 20, driven from a continuously rotating motor by a friction clutch and escapement mechanism 46, 47, is in engagement with a contact 13. The operation of relay 12<1> removes a byepass circuit from escapement magnet 48 which on operation allows the arm 20 to rotate through a distance corresponding to half the distance between the teeth of the ratchet 46. On the de-energization of magnet 48, the shaft 21 rotates to a position separated from the contact 24 by a distance corresponding to half the pitch of the teeth of the ratchet. The first impulse brings the arm 20 to the contact 24 and, if prolonged, a relay 100 operates effecting the energization of a coil 79 which positively steps a ratchet 75 on a shaft 50 carrying a number of type-wheel discs 1 ... 7. On the de-energization of the magnet 48 the arm 20 is permitted to move to a position between contacts 24, 24<1> and is moved to the contact 24<1> when the next impulse of the first group is received. At the end of the first group of impulses the arm 20 is between contacts 28, 29 and is moved to the contact 29 by the first impulse of the second group. If the impulse is prolonged, relay 100 operates, and energizes a relay 70 controlling the vertical movement of the type-wheel discs. The lower end of the type-wheel shaft 50 engages a cam 53 mounted on a shaft 54 which is rotatable by a motor through a friction clutch and a toothed clutch 65, 66 when released by the escapement mechanism controlled by the relay 70. The type-wheel discs are selectively raised by the prolonged impulses of the second group of the signal code combination and a printing impulse steps the arm 20 to the contact 35 over which relay 90 operates and actuates a hammer 91 and the tape against the selected type. A final or restoring impulse steps the arm 20 to the contact 36 by which magnets 72, 86 are energized in series. The armature of the magnet 72 moves the toothed member 65 out of engagement with the member 66 so that the cam 53 returns to its normal position through the action of a spring 60, whilst the magnet 86 removes a detent 80 from the ratchet wheel 75 which returns the typewheel shaft to its normal position under the action of a torsion-compression spring 81. At the end of the restoring impulse the arm 20 moves to the contact 13. The tape 14 is fed by a ratchet wheel 94 positively driven by a pawl 95 during the return stroke of the armature 92 of the printing magnet 90. The type-wheel discs 1 ... 7 are removably mounted on the shaft 50 and their positions may be arranged so that a message transmitted according to a predetermined secret code is printed in decoded form. The receiver and printer when used on a moving vehicle may be mounted on springs attached to brackets secured to the vehicle to absorb shocks, and the printed message may be viewed with the aid of a magnifying lens through a slot in a casing surrounding the apparatus.