Patent GB-619859-A (GB)
Title: Selecting mechanism for printing telegraph receivers
IPC: H04L17/18
Filed: 1945-12-18
Abstract: 619,859. Type-printing telegraphy. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Dec. 18, 1945, No. 34334. Convention date, June 30, 1944. [Class 40 (iii)] In a printing-telegraph receiver in which an exploring member mounted on a rotatable shaft, which may carry a type-wheel, co-operates with internally notched code rings set simultaneously in accordance with the received elements of a signal, a cam mounted on a shaft clutched for one revolution during each received signal to a constantly running motor operates a reciprocable member carrying a number of thrust bars equal to the number of code elements and co-operating with a like number of selector setting members individually associated with the code rings and storage members set in accordance with the received signal elements operate to control the connection of the cam-shaft to the motor and the permutational setting of the thrust bars which on the forward movement of their reciprocation selectively operate the selector members and their individually associated code rings. The exploring arm carries an index arm having a device for retarding the shaft when approaching its selected position. One end of the arm is arranged to enter a notch in a fixed index ring to arrest the type-wheel or like shaft in the selected position. The received signals are applied by a distributer 80, 82, Fig. 5, to a number of magnets 1, one of which is shown. When a magnet 1 is energized, its armature 2 rotates an associated tripper 7 in an anticlockwise direction to release a storage lever 11 which rotates under the action of its spring 11a and removes an extension 12 which normally supports an associated thrust bar 13. The set of thrust bars 13 is pivoted on a lever 17 and is moved to the right when an arm 17a is rocked by a hump 20 on a cam carried by a shaft 23, so that the bars 13 selectively engage toepieces 30a of setting levers 30 which engage slots in the internally-notched code rings 27 which are supported by posts 28 and are capable of slight rotation. Each ring 27 is held in its normal or selected position by a pivoted detent 33 engaging one of two notches 35 in the associated disc. The shaft 23 is released by the reception of any marking element which energizes a magnet 1, the operation of its tripper 7 and lever 11 rotating a member 14 common to all the levers 11 which releases a pivoted lever 39 to close contacts 21, 22 through which a start magnet 60 is energized when brush 86 engages segment 84 of the distributer, Fig. 5. The armature 61 of the magnet permits a spring-biassed pawl 66 carried on a cam disc 70 keyed to the shaft 23 to engage longitudinal grooves of a fluted wheel 65 driven from gears 62, 63. After one revolution of the shaft 23, the end 61a of the armature 61 rucks the pivoted pawl out of engagement with the wheel 65 and a pivoted pawl 71 restrains the disc 70 from backlash. The lever 39 in closing the contacts 21, 22 rotates against a stop 41 carried by the lever 17 and when the arm 17a is rocked by cam 20 the lever 39 is rocked in an anticlockwise direction and the levers 11 which had been released are rotated by an extension 47 on lever 17 so that the end of the member 14 is latched and the members 11 are themselves latched in their normal positions by the notched lugs 10 of the trippers 7. A hump 24 on another cam on the shaft 23 - operating subsequently to the cam 20 depresses a pivoted lever 26 so that its end, located in slots 37, restores to their normal position any rings 27 which had been rotated by the pivoted members 30. The selective setting of the code rings 27 is utilized to control the rotation of a shaft which may carry a type-wheel. The setting of any code ring 27 lifts a roller 50b out of slots 27a so that an offset lug 50a on a lever 50 releases a seeker arm 49 to be driven from a gear through a friction clutch, Fig. 4 (not shown). The seeker arm carries a four-blade wheel 58 and a coaxial cam 57 which rotate together, the blades of the paddle wheel extending across the inner surface of the code rings and the cam 57 lying in the same plane as an index arm 54 which can move longitudinally relative to the arm 49 to which it is secured by a spring 55. When a blade on the paddle wheel engages an aligned set of notches on the rings 27, the shaft 59 and cam 57 are rotated, imposing a frictional drag on the shaft 52 which is then arrested by the engagement of the end 54a of the index arm 54 with a notch 29a formed in the fixed index ring 29 and arranged in relation to the aligned slots to arrest the type-wheel or other member at the appropriate position. The resetting of the notched discs 27 lifts the blade of the paddle wheel 58 out of the aligned slots and effects rotation of the shaft 59 so that the cam 57 allows the end 54a of the index arm to be retracted from the slot 29a in the fixed ring 29. The seeker arm 49 then continues its rotation until its end 51 is engaged by the offset lug 50a on the arm 50 which moves to the position shown when the collar 50b engages the recesses 27a on the resetting of the rings 27 to their normal positions.