US2073667A

US2073667A - Sound producer

Info

Publication number: US2073667A
Application number: US502150A
Authority: US
Inventors: Williams Robert Longfellow
Original assignee: Submarine Signal Co
Current assignee: Submarine Signal Co
Priority date: 1930-12-13
Filing date: 1930-12-13
Publication date: 1937-03-16
Anticipated expiration: 1954-03-16

Description

March 16, 193 7.

SOUND PRODUCER Filed Dec. 13, 1930 2 Sheets-Sheet l /NVENTOR ROBERT L. WILLIAMS A TTORNEY R. L. WILLIAMS V Y 2,073,667 I SOUND PRODUCER Filed Dec. 13, 1930 2 SheetS-Sheet-Z m uu E I M 5 A Passer! WILLIAMS 1 ATroRNEY Patented Mar. 16, 193 7 PATENT OFFICE SOUND PRODUCER Robert Longfellow WilliamS,.Newton, Mass.,'assignor to Submarine Signal Company, Boston Mass., a corporation of Maine Applicant December 13,1930, Serial lilo. 502,150

1 Claim.

The present invention relates to sound producers and more particularly to sound producers electrically operated for producing sounds of great or small intensity.

5 Sound producers of this general type are known in the art and have been used as fog horns or sirens. In the present case my invention is an improvement onthe device disclosed in my copending applications Serial No. 288,705, filed June 27, 1928, Patent No. 1,923,959, issued August 22,

1933, Serial No. 365,385, filed May 23, 1929, Patent No. 1,977,663, issued October 23, 1934, and Serial No. 403,812, filed October 31, 1929, and has for its object to obtain a more powerful sound producer operating more efficiently and with greater reliability under all conditions particularly under strenuous service conditions.

The objects and advantages of the present invention will not here be enumerated separately for they will be more readily understood and appreciated when brought forth in connection with the description of the embodiment of the invention as shown in the drawings in which Figure 1 shows a view of the invention with a part of the casing removed; Figure 2 shows a section of the device shown in Figure 1; and Figure 3 shows a detail of the magnetic system.

In the sound producer as shown in the drawings there is provided a center element I which has formed as an integral part thereof a base 2 adapted to support the whole device. The center element I is composed of a ring portion 8 having two inwardly extending sectors or elements 3 upon which is mounted the electromag netic coil 4 for producing the electrical forces operating the sound producer. The inwardly extending portions 3, the ring 8 and the base 2, as indicated in Figure 2, form an integral piece which may be cast or forged as desired.

The coil 4 is supported in place by clamping arms 5 extending partly around the coil 4 and bolted by means of bolts 6 to the elements 3. One end of the clamping element 5 rests upon a shoulder 1 of the piece 3 and allows thereby the proper desired pressure to be exerted on the coil 4 by tightening the bolt 6 to the proper desired tension. I Mounted on each side of the ring 8 by means of the

flat head screws

9, 9 are the diaphragm elements I0, Ill. The diaphragm elements carry at their center armatures II, I I which are'shown in greater detail in Figure 3. The armatures I I,

II have threaded studs I2, I2 which screw into a slightly bossed section at the center of the diaphragm. The armatures II, II are composed 55 of three oppositely positioned pole pieces designated respectively I3, I3, I4, I4 and I5, I5. These pole pieces are rectangular in section, as indicated in Figure 1, but are cut on a bias, as shown more specifically in Figure 3, in which the bias angle is shown as approximately with the horizontal, although any other suitable angle may be used. The pole pieces are so designed that the central elements I4 are double the sectional area of the end elements I3 and i5. It should also be noted that while the air gaps 10 between the pole pieces I3, I3 and I5, I5 extend on one side of a horizontal line that the pole piece I4 extends on the other side of the horizontal line, thus making equal angles between a normal horizontal. In this manner the vertical components of the pull of the pole pieces I3 and I5 may be balanced by the vertical component of the pole pieces I4. By this manner of construction it is possible to provide an air gap having a comparatively low magnetic reluctance for a given amplitude of motion of the pole pieces.

As indicated in Figure 1, the coil 4 passes through the slots I6 and I! about the pole pieces I4 and are independently held in place by the clamping means 5, clamping the end portions of the coil 4 exterior of the pole pieces so that while the diaphragms I0 vibrate, the coil 4 remains stationary.

Bolted to the diaphragm by means of the bolts 20 is a heavy ring 2| which is threaded on the inner side at 22 to accommodate the plate 23 carrying the horn Z4 bolted to it by means of the bolts 25. The plate 23 has its distance from the diaphragm I9 adjustable by means of the screw thread at 22 and may be clamped in position when final adjustment is made by means of the clamping washer 26. The plate 23 together with the diaphragm in back of it forms an air chamber, and the proper adjustment of the plate with respect to this chamber provides a means for making a final adjustment of the resonance of the system. The resonating chamber 21 has at its lowest point a drain hole 28 to allow any water which may settle in the chamber to be drained out. The diaphragms I0, however, entirely close the inside of the device and form a water tight joint by means of the groove 29 and packing ring 30.

Within each of the horns a screen is placed to prevent foreign matter, such as leaves and the like, from getting into the resonator chambers.

The sound producer is preferably operated by alternating current though it may be operated by intermittent or pulsating current. The alternating current passing through the coil 4 intermittently increases the magnetic pull between the diaphragms l0 and produces a motion between the same. In practice this motion may be as great as 70 thousandths of an inch or more and therefore a considerable sized air gap must be provided. When, however, the air gap is large, the current in the coil 4 must be large to maintain the same flux on account of the increased ,magnetic reluctance. comes this difficulty by making the air gap at an angle to the normal motion and by so balancing the pulls on different air gaps that there is no sideways force.

Having now described myinventlon, I claim:

A device for producing continuous sound vibrations of large volume comprising a central circular base element forming a substantial part of The present invention evermerit, a chamber being :formed between each dia-,

phragm and the flange of the base element, a pair ef cooperating core elements one mounted at the center of each of the diaphragms and one of them extending through the aperture in the flange, a coil loosely surrounding said cores and means for fastening-said coil to said flange.

ROBERT 'LONGFELLOW WILLIAMS.