foerdervorrichtung to production of paper, cellulose or the like railway in zigzags through a drying room

摘要

398,897. Automatic exchange systems. TELEFONAKTIEBOLAGET L. M. ERICSSON, 33, Kungsgatan, Stockholm. March 24, 1932, No. 8847. Convention date, March 26, 1931. [Class 40 (iv).] An inter-exchange connection is held by a relay at the outgoing end of the junction operated in response to a backward A.C. impulse when the called party replies and released by a further A.C. impulse when the called party replaces his receiver, a long A.C. impulse being then sent forward over the junction, if or when the calling party has hung up his receiver, to release the distant apparatus. As described, a calling line 33, 34 in exchange A is connected over a finder switch AS to junction 23, 24, the connection being completed over group and final selectors (not shown) at the distant exchange B. Line relay R1 pulls up and operates R4 whereupon the finder hunts for the line and switching relay R5 pulls up. Impulses are repeated by R1 to R6 which repeats them over operated contacts of slow releasing relay R8 to R12 which sends A.C. impulses over the junction to set up the connection. The impulses are received by relay R15 associated with rectifiers 14 .. 17. On receipt of the first impulse at exchange B, R16 pulls up and back-stroke magnet SM2 of sequence switch S2 moves the switch to position 2 in which R16 holds and connects holding battery over the upper cam of the switch to the outgoing c wire. When the called party replies, R18 pulls up and S2 moves to position 4. In passing position 3, the switch operates R13 which sends an A.C. pulse to exchange A to operate R10 whereupon sequence switch S1 steps to position 2 in which R3 is operated to complete a further holding circuit for R4. When the called party replaces his receiver, R18 relapses, sequence switch S2 goes to position 6 and in passing 5 operates R13 to send back an A.C. pulse to operate R10 which sends S1 to position 3. R3 falls back, and, if R1 has been released by the calling party, R4 falls back and releases finder AS. When R5 relapses, sequence switch S1 goes to position 1 and in positions 4 .. 8 operates R12 which sends a long A.C. pulse to exchange B to ensure the release of R16. Sequence switch S2 goes to position 1 and the consequent removal of battery from the c wire releases the switch train at exchange B.