Patent GB-203657-A (GB)
Title: Improvements relating to apparatus for recording the duration of brief phenomena, particularly applicable to continuous marine sounding by means of sound
IPC: G01S1/72
Filed: 1923-06-22
Abstract: 203,657. Marti, P. A. D. Sept. 7, 1922, [Convention date]. Recording by coordinates; graduations of record-surface. -In apparatus for determining the duration of a brief phenomenon wherein a mechanically - operated tracing-point actuated by the current of an electromagnetic oscillograph at the beginning and end of the phenomenon is caused to produce, upon a series of repeated and identically drawn lines, corresponding indentations, the tracing point is displaced rapidly at a constant and known speed whilst the record surface is moved at a slow speed. The oscillograph is mounted at the end of a rotary arm and adjusting means are provided so that the starting of the phenomenon is recorded at the moment or at a known time before the tracing point reaches the edge of the record surface. As shown applied to apparatus for continuous marine sounding by means of sound, employing ultra-sonorous waves emitted by a quartz crystal and an induction coil, the sound emitting apparatus 31, Fig. 6, is connected to the secondary coil 34 of the induction coil and to a current amplifier 32 which in turn is connected to the conducting rings that are mounted on a shaft 4 driven at a constant speed by a motor 17 and regulator 18. The regulator comprises a spring strip and contact member which under the action of centrifugal force controls the resistance of the motor supply circuit. During the recording period the regulator is short circuited by a cam on the shaft 4 and a contact piece 19 to prevent induction. The shaft 4 carries a counterbalanced lever 3 provided at one end with an electromagnetic oscillograph 1 having a recording point 2 and electrically connected to the conducting rings on the shaft 4. The sets of sonorous waves are produced by the closing and interrupting of the primary circuit 9 of the induction coil by means of a cam 12 on the rotary arm 3 and two contacts 10, 11, in series in the circuit 9; the contact 10 is normally open and the contact 11 is normally closed. The form of record produced is shown in Fig. 3, the oscillograph producing indentations 15, 16 at the beginning and end of the phenomenon the indentations in the present application being produced respectively by the waves upon emission and upon reflection from the sea bottom. and affecting the and receiving apparatus 31. The record band 6 passes over an adjustable table 25, Fig. 5, from a supply reel 23 and is fed by pressure rollers 26, 27 actuated by means associated with the motor 17 or by means connected to the engine of the vessel or with a log so as to advance the paper proportionally to the distance travelled by the vessel. The record band is coated with lampblack by means of an oil lamp 35 and after passing through the rollers 26, 27 is passed over an inspection table 28 and through a bath 29 containing an alcoholic solution of shellac for fixing the records and is finally wound upon a reel 30. The curve 16 which in the present case represents the contour of the sea bottom according to the course of the vessel may be readily interpreted in units of depth by longitudinal graduations on the record band produced by a comb member bearing continuously or intermittently on the surface. For great depth the phenomenon may be started prematurely so that only the end of the phenomenon is recorded. The spring controlling the initial position of the recording point 2 may be adjusted to vary the distance of the point from the shaft 4 to compensate for varying physical conditions such as temperature, pressure, proportion of salt, &c. affecting the velocity of sound. The adjustment is effected in conjunction with a scale 20 arranged alongside the band 6. A watch 36 which closes an electric contact every five minutes is provided to short circuit the oscillograph during one revolution so as to effect the graduation of the record surface as indicated at 22 by the gap in the series of records.