Patent GB-208529-A (GB)
Title: Improvements in automatic calling apparatus for telephonic installations
IPC: H04M1/56
Filed: 1923-12-06
Abstract: 208,529. New Antwerp Telephone & Electrical Works Soc. Anon. Dec. 14, 1922, [Convention date]. Void [Published under Sect. 91 of the Act]. Semi-automatic exchange systems; impulsetransmitters-In an operator's sender, the number set up is visibly indicated to the operator and impulse transmission is started b a special key. In one form a sliding member of each digit is directly moved by the operator to display the required number, these members being restored during impulse transmission. In a second form, the sliding members are controlled by a single set of ten keys, which are successively associated with the sliding members. First form. The sliding members 4, 4<1>, 4<11>, Fig. 3, have finger apertures 5 which normally expose the numerals 1 - - 0 on the base board. As shown, the number set is 974, these numerals showing through apertures 7, 7', 7". Each member is retained in its set position by a catch 24, Fig. 5, on the armature of a magnet B. The catch may also be released by a button 35 in case of incorrect setting. The movement of the member 4 is communicated by a strap 9 and pulley fast on the axle 13 to a ratchet wheel 33 which slides under a pawl 31 on a disc 29, which is loose on the axle 13, and is geared to a speed-regulating worm 30<1>. Projections on the disc 29 control the impulse springs. The circuit connections are shown in Fig. 7. The operator, having set the numbers 4, 4<1>, 4<11>, depresses key K to energize relay D, which locks up over winding t<2> dependent on off-normal contact 26 of the units member 4. Magnet B<3> energizes over contacts 27, 29 and releases the hundreds member 4<11>, the upward movement of which causes the ratchet 33 to engage pawl 31 and drive the disc 29 to operate the impulse springs. When member 4" reaches normal, contact 27 opens the circuit of magnet E<3> and of a slow-release relay E<3>, which after an interval energizes a slow-acting relay C<2> which energizes the release magnet B<2> of the tens member 4'. Relays E<2>, C<1> similarly control the units member 4. Second form. The sliding members 40, Figs. 8 and 9, are set by a single set of ten keys 42, each key having a contact 47 of characteristic length to determine the coupling of the members 40 with a reciprocating carriage 46. The carriage 46, mounted on rollers 49, 49<1>, is reciprocated by an eccentric 52 on a shaft 53 which rotates once on each depression of a key. Ten springs 50 arranged beneath the contacts 47, and four magnets A, one for each member 40, are mounted on the carriage 46. When a key is depressed for the thousands digit, magnet A', Fig. 9, energizes over a normal contact m<I> controlled by member 40<I>, locks up over contact P<1> and by pressing catch 56, Fig. 8, into a notch on the member 40<I> couples the latter to the reciprocating carriage 46 until the circuit of magnet A<1> is broken between contacts 47, 50, that is for a time determined by the length of the contact 47 of the depressed key. The member 40<I> is held in its set position by a catch 60 controlled by a magnet B. When the next key is depressed, magnet A<II> energizes over normal contact m<II> of member 40<II>, contact o<I> controlled by the carriage, and off-normal contact n<I> of member 40<I>, and controls the setting of the hundreds member 40". The setting of the tens and units members 40<III>, 40<IV> is similarly effected. Each member 40 is connected by rack-and-pinion mechanism 79, 80 to a numbered drum 75 rotating behind an aperture 76. The transmission of the impulses is effected as described in connection with Fig. 7, except that a key is associated with each release magnet to enable any sliding member to be reset, if necessary, without transmitting impulses. Mechanism for ensuring a single complete rotation of the shaft 23 on the depression of a key is described.