GB464024A - Means for determining distances by reflection of waves - Google Patents

Abstract

464,024. Distance-measuring apparatus. NEUMANN, G. Sept. 3, 1935, No. 24544. [Class 118 (ii)] In a system in which distances are measured by the time taken by a wave to travel from a transmitter to a remote point and back, the wave train comprises impulses of one kind sent out at regular intervals and impulses of other kinds sent out at multiples of this interval. As indicated in Fig. 4 impulses of one frequency are sent out at times Z0, Z1, Z2, &c., impulses of a second frequency are sent out at times HI, &c. and impulses of a third kind are sent at times T1 &c. The transmission of the impulses is controlled by cams 9, 18 and 32 (Fig. 9) respectively which are driven by motor 10 either directly or through gearing as shown, the frequency of impulses being varied by cutting condensers 39 and 64 in or out of the oscillator circuit 4, 5, 6. The impulses are transmitted by transmitter 1 and the reflected impulses are received by receiver 2<1>. Filters 26, 27 and 28 allow impulses of the correct frequencies only to flash lamps 15, 29, 30 which illuminate slots 14, 22 and 33<1> in discs 13, 21 and 33. The discs are driven in synchronism with the cams 9,18 and 32 so that the position of the discs when the signal is received indicates the distance being measured. Suitable scales are provided around the discs so that the distances can be read off by observing the position of the slots when the flashes occur. A distance of 1,260 metres is indicated by the dots in Fig. 6. A cam 42 on shaft 11 opens the receiving circuit to lamp 15 when an impulse is transmitted to prevent the directly received wave being indicated. Instead of the rotating disc and single lamp, the indicators may comprise wipers 43 moving over contacts 44, (see Fig. 11), to which individual lamps 45 are connected, the lamps being provided with suitable delay networks to maintain illumination sufficiently long to allow a reading to be taken. An alarm 49 may also be provided which is sounded only when the distance alters suddenly. When a pulse is received relay 56 is energized and moves lever 55 into contact with disc 54. If the distance is unaltered or has altered by a small amount only the lever contacts with the insulated sections 59 and the alarm is not operated. If a sudden alteration has taken place the lever touches the conducting portion of the disc and the bell rings. The projections 60, 61 are provided to keep the insulated segment 59 in line with the lever 61, a friction drive beingprovided between shafts 50, 53.