US2432083A

US2432083A - Hydrophone

Info

Publication number: US2432083A
Application number: US468246A
Authority: US
Inventors: Jr Robert Black; Frank F Romanow; Oscar A Shann
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1942-12-08
Filing date: 1942-12-08
Publication date: 1947-12-09
Anticipated expiration: 1964-12-09

Description

Dec. 9, 1947. R. BLACK, JR, El" AL HYDROPHONE 2 Sheets-Sheet 1 Filed Dec. 8, 1942 FIG.

FIG: 3 30 R BLACK JR;

M W A. SHANN wvmmns' I 1947. R. BLACK, JR., ET AL 2,432,083

HYDROPHONE Filed Dec. 8, 1942 2 Sheets-Sheet 2 FIG. 6

1?. Buck, JR. EEROMA/VOW 0. A. SIM/WV hrrmir INVE N 7URS.

l rier member as to Patented 9, 1947 ICE HYDROPHONE Robert Black, Jr.,

South Orange, Frank F;

Romanow, Summit, and Oscar A. Shann, Short 1 Hills, N. J.,

oratories, Incorporated, v poration of New .York

. 'ApplicationDecember 8, 1942, Serial No. 468,246

6 Claims. (01117-386) This invention relates to submarine signal detecting devices or hydrophones.

An object of the invention is to improve the structure and the operating characteristics of hydrophones.

In accordance with the invention, a hydrophone or submarine signal detector may comprise a transducer unit so supported on a frame or carfunction on the inertia, principle, the carrier member being of such shape and resiliency as to make a substantially tight fit with a substantial area of the inner surface of a thin-walled hermetically sealed and water-tight container or enclosure. The outer surface of the container is covered with a substantially uniform thickness of rubber molded around the container. This general arrangement involves structural simplicity and ruggedness, protection of the mechanical and electrical parts against corrosion, a low order of distortion and attenuation in the signal transmission from the water to the transducer 'unit, and adaptability to quantity manufactors with reproducible response-frequency characteristics.

A more complete understanding of this invention will be obtained from the detailed description that follows taken in conjunction with the appended drawings, wherein:

Fig. 1 is a side view'of a hydrophone embodying the invention;

Fig. 2 is an end view of the device of Fig. 1;

Fig. 3 is an enlarged side View, partly in section and partly broken away, of the electromechanical assembly included in the device of Fig. 1;

Fig. 4 is an end view of the assembly of Fig. 3;

Fig. 5 is a sectional View of the assembly of Fig. 3, along the line 55 thereof;

Fig. 6 is a sectional view along the line 6--6 of Fig. '7, Fig. 7 and Fig. 8 beingv plan and side views, respectively, of the transducer unit assembly included in the str cture illustrated by Fig. 3; and

Fig. 9 is an enlarged perspective view of the transducer unit included in the hydrophone.

With reference to the drawings, the hydrophone is seen to comprise a transducer unit I included in an, assembly ll within a water-tight and hermetically sealed enclosure or container l2 that is completely covered or coated by a substantially uniformly-thick layer of rubber l3.

The transducer unit assembly will be best understood by particular reference to Figs. 3 and to 9.

The magnetic system of the transducer unit may be substantially the same as that of the telephone receiver of M. S. Hawley Patent 2,202,906 of June 4, I940. It comprises an armature IS, a pair of bar permanent magnets IS, a pair of U-shaped pole-pieces l1, current coils l8 surrounding the inner arms of the pole-pieces,

assignors to Bell Telephone Lab- New York, N. Y., a cor- 2 I and a. spider member l9 providinga mechanical stillness member coupling the armature to the other components of the magnetic system, the

' Dole-pieces and magnets being welded together and the spider member being fastened to the pole pieces by screws 20, all of which is described in greater detail in the aforementioned Hawley patent. In the present arrangement, the magnetic system is fastened to the planar portion 2| of a D-shaped frame member or chassis 23' by fastening means 22. whereby, since the armature is soldered to the spider member, the armature, the other components of the magnetic system as a group, and the chassis are adapted for relative movement on vibration, for example, of the chassis. The planar portion of the frame member contains an appropriately shaped aperture 24 for the armature, and additional apertures through which insulated Wires or leads 25 may be drawn for electrically connecting theends 2B of the current coils with terminals on the centainer i2. The frame member-may be of a nonmagnetic metal. such as brass, and, except for its planar portion 2!, substantially annular in crosssection. The curved portion of the frame member is divided intoa pair of substantially similar but opposed arcuate portions 2! by a slot or slit 28 extending along the length of the frame member at a location substantially intermediate the junctions of the curved portion with the planar portion. When the transducer unit assembly is outside of the container l2, the arcuate portions 2'! are sprung apart, for example, as illustrated by Fig. 6. When the assembly is inside of the container, the portions 21 are forced together, as i]- lustrated by Fig. 5, the tendency of the arcuate portions to restore themselves to the condition of Fig. 6 resulting in an exceptionall tight fit between the frame member and a substantial area of the inner surface of the container, to provide an excellent vibration transmission relationship between the container and the frame member and, therefore, the transducer unit. In slidably inserting the assembly I! in the container during manufacture of the hydrophone, the arcuate portions 21 would be forced together sufficiently for the purpose.

The container l2 comprises a thin-walled, metallic envelope 3|] substantially cylindrical in shape, formed with a closed end portion 3| of slightly reduced diameter and an open end portion provided with an outwardly flaring annulus 32. The latter end portion may be closed by a closure assembly 33 having a central opening closed by a disc 34 of insulating material, a shoulder portion 35 that may. be ring welded to the annulus 32 and an annular skirt 35 bent over portions 31 of which hold a terminal plate 38 of insulating material securely within the closure assembly. The disc 34 may be cemented in position and supports a pair of connector wires 39 electrically connecting the leads 25 with the terminals 40 on the plate 38. The conductors 4| of the v cable 42 for connecting the hydrophone with suitable electrical equipment (not shown) in a vessel or on shore are brought into the container through suitable apertures in the plate 38 and terminated at the terminals 40. All the metallic joints of the container assembly are water and air tight, the sealed-off tubingMlbjeing the remnant of a tube extending through the disc 34 for introducing, prior to the' addition of the plate 38 to the ciintainer assembly, air at substantial pressure to test the hermetic character of the seals. The envelope 30 and all but the disc. 34 of the closure assembly may be of a magnetic material, such as steel. A disc 42' of similar material, provided with suitable apertures for the'connectors 39 may be inserted in the closure assembly opening over the disc 34 to provide a closed magnetic shield aro'und the'transducer unit to protect it against the effect of magnetic fields developed during the welding operations as well as against the effect of magnetic fields that may be present in the environment in which the hydrophone may be used.

During the assembly of the hydrophone, after the transducer unit assembly is inserted in the envelope 30, the latter may be forced slightly into the reduced diameter portion 3| to ensure rigid coupling between th frame member and the envelope. The "air and water-tight character of the seals and joints... of the container may be tested, prior to securing the terminal plate in position, by use of air under pressure introduced through the tubing 44 while the container is held under water or in carbon tetrachloride. The rubber layer [3 is molded around the container and the container end of the cable 42 as the last step of the manufacture. The responsefrequency characteristic of the device may be measured at intervals to ascertain that it remains within permissible limits before the next assembly step.

In use, the hydrophone is submerged in water, for example in a lake, a river or the sea, at the end of a suitable suspension, or may be included with a number of similar devices at spaced intervals in a cable, for example, extending across the mouth of a river or the entrance to. a harbor. Submarine signal waves or other underwater disturbances in the audio frequency range will cause the hydrophone to vibrate. These vibrations produce relative movement between the spring coupled armature and .the remaining structure ofthe transducer lunit magnetic system, whereby the variationin the reluctance of the magnetic circuit induces currents in the coils on the pole-pieces that correspond to the signal waves or disturbances. These currents are led over the conductors of the cable to suitable electrical indicating or translating equipment in a vessel or at a shore station. The outer rubber layer protects the container against the corrosive effects of the water. the thin-walled envelope efficiently transfers vibration to the D-shaped frame member and the latter effectively transfers the disturbance to the; transducer unit.

Although the invention has been disclosed with reference to a specific structure} it is evident that modifications therein may be made by the skilled 4 V in the art without departing from the invention.

What is claimed is:

1. A hydrophone comprising .a water-tight hermetically sealed cylindrical container, a spring metal frame member adapted to be wholly included within said container, said frame member being 'slidably insertable in said container and expans'ible therein to make a tight fit with a substantial area of the inner surface of the latter, and an electromechanical transducer unit mounted on and supported solely from said member so as 'to respond to vibrations transmitted to said frame from said container.

frame member is substantially D-shaped in sec- 3. The hydrophone of claim 1 in which said frame member is substantially D-shaped in section with the curved portion of the D-shaped frame in close contact with .the inner cylindrical surface of said container and the transducer unit supported from the planar portion of the frame member. I

4. The hydrophone of claim 1 in which said frame member is substantially D-shaped in section, the curved portion of the D-shaped frame having approximately the same radius of curvature as the cylindrical container, said frame having a slot extending along the length of its curved portion.

5. The hydrophone of claim 1 in which said frame member is substantially D-shaped in section, the curved portion of the D-shaped frame having approximately the same radius of curvature as the cylindrical container, said frame having a slot therein extending along the length of its curved portion approximately intermediate the junctions of the planar and the curved '45 portions of the member.

6."The hydrophone of claim 1 in which said frame member is substantially D-shaped in section, the curved portion of the D-shaped frame having approximately the same radius of curva- 50 ture as the cylindrical container, said frame having a slot extending along the length of its curved portion approximately intermediate the junctions of the planar and curved portions of the member, the transducer unit being supported 5 from the planar portion of the member.

ROBERT BLACK, JR. FRANK F. ROMANOW. OSCAR A. SHANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 2. Thehydrophone of claim 1 in which said-