Improvements in or relating to telegraphic receiving apparatus


284,740. Creed & Co., Ltd., and Salmon, R. D. Sept. 3, 1926. Type-printing telegraphs.-In a motor-driven telegraphic receiver the motor and a driving shaft of the apparatus are started automatically by the receiving relay on receipt of a starting signal, continue to run during the receipt of subsequent signals, and are stopped automatically when signalling has ceased for a predetermined time, the relay being inoperative on the motor-starting means after the receipt of the starting signal. Fig. 1 shows the application to the type-printing receiver described in Specification 228,842. The circuit of the driving motor 13, Fig. 4, includes switch contacts 1<b>, 2<b> carried respectively on the U-shaped end of a pivoted arm 1 controlled by a spring 4 and on a pivoted arm 2 controlled by a spring 5, and a stop 6 between the limbs of the U limits the movement of the arm 1. The spring 5 connects the arm 2 to a third: pivoted arm 7 and normally holds the switch open with the arm 7 above the free end of the arm 2 until the latter is acted upon by a crank member 8 carried by a spindle 9 axially movable in a bearing 9<a1>, Fig. 5. A collar 9<a> on the spindle is engaged by a fork 18 for moving it axially against the action of a spring 13, and springs 11, 12 acting on a block 10 secured to the spindle tend to rotate it in a direction to cause the member 8 to close the switch. The spindle passes through the centre of a disc 14, provided with diametrically opposed holes 14<a> and rotated slowly through worm gearing from a shaft 17, Fig. 1, driven by the motor B. With the motor at rest and the end 8<a> of the crank member 8 in engagement with one of the holes 14<a>, the receipt of the first signal by the relay 22 causes the relay tongue 21 to actuate, through a link 21<a>, a bellcrank 20, 20<a> of which the arm 20<a> acts on the block 10 to slide the spindle 9 against the action of the spring 13, thus disengaging the end 8<a> from the hole 14<a> and allowing the springs 11, 12 to rotate the spindle for closing the motor circuit. The arm 7 thereupon snaps into position to lock the arm 2 in switch-closing position, and a notch 10<a>, Fig. 5, in the block 10 is brought opposite the arm 20<a> leaving the end 8<a> free to re-engage one of the holes 14<a>. The disc 14 is now rotated slowly, moving the member 8 towards the arm 7. As long as signals are being received the fork 18 is operated periodically to slide the spindle 9 for disengaging the end 8<a> from the hole 14<a>, this operation being effected from a cam c, Fig. 1, driven from the motor B under control of the signals, and occurring before the member 8 reaches the arm 7. When, however, the signals cease, the fork 18 is no longer operated and, after a predetermined time, the member 8 acts on the arm 7 to allow the switch to open thus stopping the motor. The invention is also applicable to the type-printing receiver described in Specification 285,100.




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