US1378940A - Amplifier for telephonic transmitters - Google Patents

Description

H. T. DALE.

AMPLIFIER FOR TELEPHONIC TRANSMITTERS. APPLICATION FILED MAR. 31.1919.

1,378,940. Patented May'24, 1921.

HARRY T. DALE, OFNEWYORK, N. Y.

AMPLIFIER FOR TELEPHQNIC TRANSMITTERS.

Specification of Letters Patent. Patented lllay 24, 1921.

Application filed March 31, 1919. Serial No. 286,274.

To all whom it may concern.-

Be it known that I, HARRY T. DALE, a citizen of the United States, and a resident of New York city, borough'of Manhattan, in the county and State of New York, have invented certain new and useful Improvements in Amplifiers for Telephonic Transmitters, of which the following is a full, clear, and exact description. V

Among the principal objects which the present invention has in view are: to perfect the transmission of audible sound waves to the diaphragm of an electric transmitter; to intensify the said sound waves; to avoid outside disturbances; to collect sound waves over a large area and concentrate the same upon the center of the recording disk; and to provide an attachment for the usual transmitter used in the mechanical aids for the deaf, whereby the sound intensity may be 7 augmented.

Drawings.

Description.

The amplifier is intended primarily for use in conjunction with the transmitters of instruments used as aids for the deaf, and generally known in the trade by the name of audiphones. 7

As shown in Fig. 3 of the drawings, the transmitter indicated by the numeral 12 has a cover cap 13. This cap usually presses.

upon a gasket which holds the diaphragm of the transmitter in service. A shoulder 14 is formed on the cover 13. This shoulder is taken advantage of when using the present amplifier, the wall 8 of the amplifier being rabbeted to form a seat 15 which rests upon the shoulder 14. A relatively thin gripping section 9 is thus formed. The section 9 is employed to frictionally grip the side or perimeter of the transmitter 12. I

The amplifier is preferably constructed of hard rubber which is sufliciently resilient where the thin portion is formed to accommodate difi'erent characters of transmitters and variations in the standard types.

The wall 8 of the amplifier is made thick to avoid inherent vibration- At the upper edge of the wall 8, the material is shaped to form the inturned funnel-like member 10. It will be noted that the edge of the member 10 is made very thin toward the center and particularly adjacent the opening 11. The opening 11 registers with the perforated central portion of the cover 13. The wall terminating in the member 10 operates to concentrate the sound waves for delivery through the opening 11. The member 10 is depressed as best shown in Fig. 3 of the drawings to form an annular chamber 16.

Due to the depression of the thin wall of the member 10 at the opening 11, the air which is contained in the chamber 16 is substantially trapped. When the sound waves are delivered into the chamber or into the space between the outer wall of the amplifier 8 and theouter wall of the cover 13, the body of air in the chamber 16 is vibrated. Due to the shape of the inner surface of the said chamber, these vibrations are first deflected from the inner surface of the wall 8 to the over-hanging inner surface of the wall 10 to be thereby deflected toward the central perforated portion of the cover 13. The vibration of the air contained in the chamber 16 multiplies the effect on the diaphragm when delivered through the area covered by the perforations in the cover 13, directly over the center of said diaphragm.

' As a result of this amplification of the vibration the sound waves are intensified and the diaphragm is more violently operated upon with the result that the microphone or transmitter 12 delivers a corresponding electric oscillation to the telephonic system in- While I prefer to manufacture the amplifier from hard rubber, it will be understood that a variety of materials may be used.

To assist the gripping portion 9 in accommodating a variety of sizes of the transmitter 12, I sometimes provide the edge 9 with longitudinal slits 17 as best seen in Fig. 2 of the drawings. This separation of the thin having an annular rigid portion adjacent 10 portion 9, permits slight expansion thereof. and integral With saidannular wall; and a thin vibrant portion integrally formed with said annular portion adjacent the said open- As an article of manufacture, a removable ing for forming a sensitive vibrant member slip cover for a telephonic transmitter, said for amplifying the acoustic vibration under 15 cover having a relatively thick annular Wall said top. and a top, the center whereof is pierced to I I form a single contracted opening, said top HARRY T. DALE.

Claim.

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