Patent GB-191025319-A (GB)
Title: Improvements in or relating to the Location of a Source of Sound Apparatus therefor.
Inventor: CASSEL ELMER FRANCIS
IPC: G01S1/72
Filed: 1910-10-31
Granted: 1911-10-31
Abstract: 25,319. Cassel, E. F. Oct. 31. Locating sounds.-The distance and direction of a source of sound are indicated directly by pointer-and-dial apparatus, means being provided for clutching the pointers to power mechanism during the interval that elapses between the arrival of a sound at two points, or between the arrival of simultaneously transmitted signals of different sorts, such as wireless and subaqueous or atmospheric audible signals. The " distance " pointer is carried by a sleeve 31<1> carrying a gear 34, which can be engaged with a motor-driven gear 82 by depressing a key 30. The key 30 is pressed when, for instance, a wireless signal is received, and is released on the subsequent arrival of a sound-signal. The pointer then indicates the distance on a scale 20. The pointer can be returned to zero by lifting the key 30 to engage a flange 35 with a reversely running gear 85. The " direction " pointer is on an inner sleeve 41 having a bevelled flange 42, which normally lies between two driving-wheels 83, 86 constantly rotated in opposite directions by a motor 88. Keys 32 and 33 are depressed at the moments when a sound arrives at two observation points such as the two ends of a ship. The key 32, which engages a groove in the sleeve 41, has its fulcrum supported from the key 33 and is pressed by a spring 51 against a stop 49. The key 33 pivoted at 48 is pressed against a stop 50 by a spring 52. According to which key is depressed first, the flange 42 is engaged with one or other of the wheels 83, 86, and the pointer turns in one or other direction. When both keys are depressed, the flange 42 is again disengaged and the pointer indicates on a scale 21 the direction from which the sound is coming. One of the keys 32, 33 is operated manually at the first observation point; the other is connected by a switch 65 for electric actuation by a key 57 at the second observation point. A magnet controlled by a contact on the key 32 puts a brake on the sleeve 41 except when the key is depressed. The scales 20, 21 are adjustable by devices 25, 25<1>. The distance and direction indicators may form separate instruments, and the latter may include oval correcting-gears so that when the index stops it may point more correctly to the source of sound. The direction indicator may have a rotatable shield for covering up the idle half of the dial, and this shield may operate contacts for selecting which of the keys 32, 33 is to be operated electrically, at the same time covering that key so that it cannot be operated manually. A device is described by which the release of the distance key 30, on the arrival of a soundsignal, automatically operates one of the keys 32, 33, so that only one key has to be attended to by the operator in charge of the instrument. The apparatus shown in Fig. 15 enables an observer on a ship that is travelling at a known speed to determine the direction of a fixed station which gives out signals at regular known intervals. An index on the spindle sleeve 117 points normally to the vessel's bow. It is connected through multiplying-gear and a lostmotion device 108, 109 to a flange 42<c>, which is slidably feathered on the sleeve which carries the disk 108 and is operable by a key 30<c> to engage it with a motor-driven wheel 86<c>. The key 30<c> is held down at the arrival of one signal and is released at the arrival of the next. The interval evidently depends on the direction of the source of the signals, and the speed of the driving-motor and the amount of the lost motion between the wheels 108, 109 are such that the index when it stops points to the source of the sounds. The lost-motion device may be dispensed with by arranging that the motor effects an exact number of revolutions of the index in the interval between the arrival of the two sounds when the ship is heading straight for the signal station. The invention is applicable in the navigation of ships during fog, &c., and for locating concealed guns or guns using smokeless powder.