Patent GB-190309231-A (GB)
Title: Improvements relating to Electric Telegraphy
Inventor: BROWN SYDNEY GEORGE
Filed: 1903-04-23
Granted: 1904-05-21
Abstract: 9231. Brown, S. G. April 23. Telegraphs. - In translating from cable code to double - current Morse, the equality in length of the positive and negative cable signals is balanced by using a long spacing- current after the "dot" and a short s p a c i n g - current after the "dash" in the Morse signals, as shown at Fig. 1<b>, this being known as a " hybrid " code. Fig. 2 shows " inter- " polator " or translator apparatus of the character described in Specification No. 17,786, A.D. 1899, the relays being omitted. The "dot" and " dash " electromagnets g', h<1> are controlled by the dot and dash cable relays, and serve themselves to control the clutch-driven shafts a, b, which carry the cams c, d. These cams control the contact levers i<2>, i<3> which serve to close the circuit of the sounder or relay e for short or long periods, thus sending dot and dash currents to the line L followed by long and short spacing currents transmitted through the back stop contact. Translation from the " hybrid " code into positive and negative cable signals is effected by means of the apparatus shown in Fig.3. The " hybrid" signals are received from the line L by a relay p, which puts the battery a for short or long periods across the wires b, c. The electromagnets m, m<1>, which control the clutches of the cams l, l<1> are thus released, and the electromagnet o energized. Momentary contact is made at x after half a revolution of the cam l, and contact is made at y during the second half of the revolution of the cam l<1>. The contact at x causes a current to flow through the coils of the neutral polarized relay q in one, or other, direction, according as the armature o<1> is, or is not, attracted at the time. As the contact takes place after half a revolution of the cam l, which runs at the same speed as the transmitting-instrument, the position taken up by the tongue q<1> depends on whether a dot or a dash has been transmitted, as shown by the lines l<2>, l<3> intersecting the hybrid signals in Fig. l<b>. The position taken up by the tongue q<1> determines which of the two electromagnets r, r<1> shall be energized by the contact at y during the second half of the revolution of the cam l<1>, that is, whether a positive or a negative signal shall be sent to the cable C. The signals in the hybrid code are thus transformed into cable signals of the usual character. An automatic transmitter for the hybrid code signals is shown in Fig. 4. The paper is perforated at equal intervals, on one side of the central line for " dots and on the other side for " dashes." The double-current transmitter x is actuated by an electromagnet x<1> the circuit of which can be closed by one or other of two contact levers t, t<1>. At the beginning of a signal, a cam u<1> on a rotating shaft releases the two " feeling " rods or fingers m, n for a moment, and one or the other passes through the paper and throws over the " dot " or the "dash" contact lever. Two other cams v<1>, w<1> on the same shaft are adapted to restore the contact levers to the normal position, in which the circuit of the transmibting-magnet is open, the "dot" contact lever being actuated after one quarter of a revolution, and the " dash " contact lever after three quarters. Hybrid signals are consequently transmitted. To transform hybrid Morse signals into ordinary Morse signals in the recording-instrument, the arrangement shown in Fig. 5 may be employed. The lever F, which carries the ink-wheel for making the record on the paper strip E is raised for short or long periods when "dot" or "dash" currents reach the relay G. The shunted relay H is, however, only energized when " dash " currents are received, in which case the electromagnet I<2> is energized, and an extra feed is given through the ratchet-wheel B to the paper strip, thus avoiding the short space, which follows the " dash " in the hybrid code. Fig. 6 shows a modification, in which the discharge from an inductive shunt L energizes an electromagnet K<1> in parallel with it and checks the feed of the paper E after a "dot." If a "dash" is sent, the slowly-acting electromagnet H<3> becomes energized and the discharge of the inductive shunt takes place through the contacts H<2>, the feed of the paper receiving no check.