US1478574A - Acoustic instrument - Google Patents

Description

Dec. 25 1923. 1,478,574

A. MARR ACOUSTIC INSTRUMENT Filed 001;. 4. 1921 meme o. 25, 1923.

um'reo STATES ALEXANDER ma, or m, mum).

ACOUSTIC mmum'r.

Application fled October 4, 1,021. led-l In. 50').

T 0 all whom it may concern Be it known that I, ALEXANDER MARK, a subject of the King of Great Britain and Ireland, and a resident of Manchester, in.

the county of Lancaster, Engalnd, have invented certain new and useful Improvements in Acoustic Instruments, of which the following is a specification.

This invention has reference to sound wave concentrators for acoustic instruments for the transmission of sound, such as for example, telephone transmitters, gramophone and like record producers, dictating machines, ear trumpets and the like, of the kind consisting of a conical or conoidal mouthpiece or equivalent fitted at its larger or sound entering end with a plate or cap provided with a constricted aperture, or apertures and removably mounted on or in the mouthpiece or equivalent.

The object of the invention is to provide an improved removable apertured plate or cap, which, while being equally efficient as plates or caps hitherto proposed, can be readily removed for cleaning or otherwise as occasion requires, and replaced in position.

According to this invention, the concentrator plate or cap (hereinafter in this description and the appended claims referred to as the cap) is made of elastic material such as india rubber so that when fitted on the mouthpiece or equivalent (hereinafter referred to as the mouthpiece) it is stretched or tensioned and securely grips the wall thereof.

In the accompanying drawing, Fig. 1 is a side view and Fig. 2 a front view of a telephone transmitter the mouthpiece of which is fitted with one form of concentrator ea in accordance with the invention. Fig. 3 1s a view of the inner or rear face of the I teferring to the drawing, 4 is the transmitter, 5 the usual mouthpiece thereof, and

6 the concentrator cap apertured at 7 The cap is made of elastic india rubber. and on its inner face is formed with a spigot por tion 8 adapted to enter the mouthpiece 5, and with a flange 9 spaced from and con- 'centric with the spigot portion 8 and adapted to embrace the wall of the mouthpiece.

" The spigot portion 8 and the flange '9 are made of such external and internal sizes and shapes that when the cap is fitted in position, as shown, the spigot portion 8 makes an air-tight joint withthe internal surface of the wall of the mouthpiece, and the flange 9 tightly grips the mouthpiece to retain the cap in position thereon.

The spigot portion 8 is rounded at 10 from the point where its inner end or edge meets or joins the inner surface of the wall of the mouthpiece.

A concentrator cap in accordance with the invention as aforesaid is efficient in use, can

be readily fitted in position and removed therefrom, can be readily cleaned, and is not liable to be broken or damaged.

Instead of the aperture 7 of the cap being of circular shape, as illustrated, it may be of elongated or slotted or any other desired shape, or a plurality of apertures may be provided in the cap.

What I claim as my invention and desire to secure by Letters Patent is 1. Aconcentrator cap for mouthpieces of acoustic instruments, said cap being made of elastic material, apertured for the passage of sound waves, and having an embracing flange adapted to be stretched over the flared end of the mouthpiece so as to be held thereon, said cap also having a short spigot flange extending within the mouthpiece and engaging at its edge with the inner wall of the mouthpiece.

' 2. A concentrator cap for mouthpieces of of elastic material, apertured for the assa-ge of'sound. waves, and having an emgracin flange adapted tobe stretched over the flare end of the mouthpiece so as to be held thereon, said cap also having a spigot flange with a concave inner face extendin within the mouthpiece into engagement wit the innerwall of the mouthpiece and engaging at its edge with the inner wall of the mouthpiece.

3. A concentrator cap for mouthpieces of acoustic instruments, said cap fitting over the flared end of the mouthpiece and having a flange extending into the mouthpiece and terminating a short distance from the flared end, said. flange having a concave inner face.

4. A concentrator cap for mouth ieces of acoustic instruments, said cap fitting over the flared end of the mouthpiece and having a flange extending into the mouthpiece and terminating a short distance from the acoustic instruments, said can being made flared end, said flange having a concave inner face facing toward the small end of the mouthpiece. V

5. A concentrator cap for mouthpieces of acoustic instruments, said cap having an elastic flange stretched over'the flared end of the mouthpiece and having a second flange extending into the mouthpiece and terminating a short distance from the flared 15 having an aperture therein for the passage of sound Waves and having a flange extending from the inner face along the inner face of the mouthpiece.

7. A concentrator cap for mouthpieces of acoustic instruments and the like, said cap fitting over the flared end of the mouthpiece and extending across the flared end, the cap having an aperture therein for the passage of sound Waves and having a flange extending from adjacent the aperture to the inner face of the mouthpiece, the exposed face of the flange being concave.

In Witness whereof I havehereunto set my hand.

ALEXANDER MARR.

Images