Patent GB-159316-A (GB)
Title: Improvements in telegraphy
IPC: H04L5/04
Filed: 1919-11-25
Abstract: 159,316. Heurtley, E. S., and Muirhead & Co., Ltd. Nov. 25, 1919. Type-printing telegraphs; distributor systems.-In systems of telegraphy using equal periods of line time for each letter &c., one set of line impulses actuates two or more receivers through the use of changes of polarity and of two or more distinct amplitudes of voltages, the impulses being sent by the simultaneous action of two or more transmitters. In an example of transmitting apparatus, Fig. 1, for working two transmitters simultaneously, the distributor F has two sets of segments A, B, C &c. and A<1>, B<1>, C<1> &c., and two brushes D, D<1> connected respectively to line and earth. Each segment in one ring has a corresponding key in one transmitter, and each segment in the other ring corresponds to a key of the second transmitter. As the brushes D, D<1> pass on to the segments A, A<1>, if the key X alone is depressed, the negative pole of the battery V is put to line, the other pole being earthed through the upper fixed contact of the key X<1>, the tongue M and the contact H of the relay LMHT, and the segment A<1>. Similarly, if the key X<1> alone is pressed. the battery V is put across line and earth in the reverse direction. If the keys X, X<1> are both depressed the coil L of the relay LMHT is energized by the battery V<3> through the additional contacts SP and S<1>P<1> of the keys X, X<1> and the tongue moves to the stop T of the relay, the batteries V, V<2> being put. across line and earth in series. The operation of the keys Y, Y<1> is identical, as many keys being used on each group as there are code elements in each letter in the system used. A modification is shown in which a single battery replaces the batteries V, V<2>, half or the whole of it being used according to the signals. Additional batteries may be used to provide further changes of voltage. In a further modification, the variations on amplitude are obtained by applying the voltage to line for different periods of time. In this case, each of the distributor segments in one ring is divided into three parts and one or all of the parts is, or are, energized to the signals to be sent. Other methods', in which the relay LMHT causes variations in the capacity or resistance of the line, may be used. In the receiving apparatus, Fig. 3, the line relays are set with their tongues K<1>, L<1> normally between their respective contacts and are so constructed that the tongue K<1> only is influenced by the weaker line impulses, both being affected by a strong impulse. The distributor segments A<2>, B<2>, C<2>, are each connected to two selector magnets X<2>, X<3> &c. and the brush D<2> rotates synchronously with the transmitter brushes. The selector magnets X<2>, Y<2>, Z<2> of one printer, or X<3>, Y<3>, Z<3> of the other, or both sets together are actuated through the battery E and the segments A<2>, B<2>, C<2> according as the relay tongue K<1> contacts with the stops M<1> or N<1>, or the two tongues K<1>, L<1> contact with the stops M<1>, O<1> together. An arrangement is shown, Fig. 5, for saving line time. The receiving distributor has two sets of segments A<2>-E<2>, A<3>-E<3>, the number in each set corresponding to the number of elements in a code letter. Additional segments R<4>, S<4>, T<4>, R<3>, S<3>, T<3> are provided and also a continuous segment D<4>. Assuming the brush D<2> to have passed over the segments A<2>, E<2>, the line relays acting as in Fig. 3 will have - caused the tongues of some of the neutral tongue relays 1-5, 1*-5* to move to the right, through the medium of the battery E' and the relay coils 1<c>-5<c>, 1<d>-5<d>. When the brushes D' pass on to the segment R<3>, current from the battery E<2> flowing through the local circuits completed by the relay contacts 1<b>, 1<a>, &c. operates the appropriate selector magnets X<2>, X<3> &c. When the brushes D<3> reach the segment S<3> the pointers UV<1> are operated in accordance with the selector magnets set. When they reach the segment T<3> the battery E<2> sends a current through the .coils 1<e>, 1<f>, &c. of the relays to restore their tongues to the spacing position. Meanwhile the tongues of certain of the relays 6-10, 6*-10* have been moved to the right in accordance with the signals received through the segments A<3>-E<3> and the brush D<2>. The brushes D<3> in passing over the segments R<4>, S<4>, T<4>, set the selector magnets in accordance with the positions of the tongues of the relays 6-10, 6*-10*, operate the printers and restore the relays 6-10, 6*-10* to normal, the relays 1-5, 1*-5* being set meanwhile. Additional arrangements on the distributor restore the selector magnets to normal after each printing impulse. A transmitting system, Fig. 6, embodying the same principle has a double set of distributor segments for each of two transmitters. Two additional segments H<1>, J are provided and a continuous conducting strip K<2>. Assuming the relays 1<g>, 1<h> &c. to have been set by the action of the key levers X, X<1> &c., suitable impulses will be sent to line through the segments A, A' &c. and the brushes D, D<1> as in Fig. 1. As the brushes K pass over the segment H' the battery V<4> is put across the coils 6<j>, 6<k> - corresponding to the second sets of segments and restores their tongues to normal. As the brushes pass over the segment J, the battery V<4> acting through the coils 61, 6<m> &c. of the same relays sets them in accordance with the keys X, X' &c. depressed. On further movement of the brushes, suitable impulses are sent from the segments A<2>, B<2>, and the relays on the left of the figure are similarly re-set and set. The second contacts on the relays and the relay HTM have the same function as the similar parts on Fig. 1. The transmitter keys may be operated manually or by a perforated slip. In the application of the invention to the Murray system, the transmitters may be geared to run in unison. The Provisional Specification states that the system may be worked in duplex.