Patent GB-559538-A (GB)
Title: Improvements in or relating to electrical timing arrangements
IPC: H04M3/12
Filed: 1942-08-20
Abstract: 559,538. Condenser arrangements. JONES, C. E. P., and HOTHAM, J. W. Aug. 20, 1942, No. 11700. [Class 38 (iv)] [Also in Groups. XXXIX and XVIII] In systems for generating one or more impulses of a predetermined duration immediately or a predetermined time after an initiating impulse or for measuring the duration of repeated impulses, a number of condensers are connected to a corresponding number of contact segments arranged in a ring and co-operating with brushes there being uniform relative motion between the segments and the brushes, a condenser being charged in response to the initiating impulse over one brush and subsequently producing an effect over another brush. The condensers may be in the form of small pieces of foil mounted on one side of a rotating disc of insulating material having a continuous foil on its other side. The analagous drum arrangement may be used. Applications described in detail include the keeping of an electric motor to a constant speed, the measurement of the length of impulses in a train and the generation of impulses of a predetermined length for impulse regeneration in an automic telephone exchange system or for accurate time measurement. Applications mentioned but not described in detail include vehicle timing, echo sounding, and timing telephone calls. In the arrangement described in the Provisional Specification, the initiating impulse charges two condensers oppositely and these act in succession on a single gas filled thermionic tube biased to an unstable condition to start and stop a discharge but in the arrangements described in the Complete Specification, only one direction of charge is employed and the charges act on the respective tubes of pairs of tubes coupled so that only one can discharge at a time. Regulating speed of motor. Fig. 4.-A pendulum operates relays LC, RC alternately. IC connects brush BI to a charging source and RC connects a brush B6 to a discharging circuit and multiplied groups of brushes B2, B4 to pairs of tubes V1, V2 and V3, V4 respectively. The distributer segments are driven by the motor and if the speed of the latter is correct, the segment connected to the charged condenser reaches B6 when RC operates, the condenser is discharged and no controlling action takes place. If the motor is too slow however, a circuit is made over the group of brushes B2 and a discharge takes place in V1 to energize SM which cuts a resistance into the motor field circuit and connects up a brush B3. When the segment reaches this brush it causes a discharge in V2 and that in V1 therefore stops and SM is released. The condenser is finally discharged over BC. Similarly, if the motor runs too fast, a relay FM is operated by tube V3 controlled over brushes B4 to cut resistance out of the motor field circuit. The arrangement may be modified by the elimination of brush B6 so that SM or FM operates on each rotation of the commutator. Measuring duration of impulses in a stream.- The apparatus described in the preceding paragraph may be modified so that the beginning and end of each impulse operate LC and RC respectively and the brushes may be rotatable together, the grouped brushes controlling the operation of lamps. When the position of the brushes corresponds to the duration of an impulse, neither lamp glows and for other settings one or other lamp glows. The glow in the tubes V1, V3 themselves may be observed instead. The apparatus may be further simplified by the omission of one set of grouped brushes and its associated apparatus. Measuring duration of an event, Fig. 7.-On the operation of key SK, ST energizes TG which locks up and a momentary charging impulse is given to the condenser connected up at this instant by B1. When the segment of this condenser reaches B2, a discharge in V1 energizes X which is followed by XX. This gives an impulse over B1, to a further condenser, and disconnects B2 and also BC1 over which the first condenser discharged before XX could pull up. The second condenser thus produces no effect until it reaches B3 whereupon it causes a discharge in V2, and is then discharged over BC2. The discharge in V2 stops that in V1 and X falls followed by XX to charge another condenser over B1. X therefore continues to pull up and fall back at precisely determined intervals, starting a predetermined time after the operation of key SK, and at each operation steps a counter M. On the relapse of ST, when key SK was released, TM pulled up and consequently, when ST is operated a second time, KO pulls up and locks and stops the generation of further impulses. The meter M thus registers the time between the two operations of key SK. The apparatus is reset by key RK. The unit period may be large or small and the starting and stopping of the measuring period may be effected under photoelectric or other control. For example, in measuring telephone calls the unit period may be one minute and it may begin as soon as the connection is completed. Impulse regenerator Figs. 5 and 6.-When the apparatus is seized, A and B pull up and the received digits are repeated to a switch RV which, at the end of each digit, charges a register condenser and moves to a new starting position under control of a relay C, CC. At the beginning of each digit, C makes a circuit over RV3, SD3, if these wipers are in corresponding positions, to cause discharge in V3. If not it charges a home position condenser such as QR1, so that the discharge may occur subsequently. When V3 discharges, SS pulls up energizing SC which connects V4 to wiper SD3 instead of V3. At the same time a condenser charging impulse is given over B1. When the segment of the charged condenser reaches B2, a discharge occurs as VI and X, XX pulls up to charge a further condenser. The first condenser has time to discharge over BC1 but owing to the operation of XX the second condenser produces no effect until its segment reaches B3 whereupon V2 discharges and the discharge in VI stops, X and XX falling back to charge a third condenser. X thus continues to pull up and fall back with a frequency and make to break ratio determined by the speed of rotation of the commutator and the position of the brushes. The first operation of X energizes P which locks when X falls in series with Q. The next impulse similarly energizes R, S and releases P, Q, and the third energizes T and Q leaving S.R energized so that subsequent impulses act on the stepping magnet of switch SD and are repeated over the outgoing circuit. When SD reaches the charged register condenser, a discharge occurs in V4, that in V3 stops and SC is released, stopping the impulses and releasing P ... T whereupon SD proceeds to its next home position and the sending of the next digit, if any, begins. Specification 558;298, [Group XXXIX], is referred to.