US1786949A - Sound-propagating diaphragm - Google Patents

Description

Dec. 30, 1930. M. R. HUTCHISON I 1,786,949

"SOUND PROPAGATING DIAPHRAGM Filed May 2. 1928 IN VEN TOR.

Z BY 'ATTORNEYJ,

Patented Dec. 30, 1930 UNITED STATES PATENT OFFICEV MILLER REESE HUTGHISON, OF LLEWELYN PARK, WEST ORANGE, NEW JERSEY, AS

SIGNOR TO PREMIER LABORATORY COMPANY, A CORPORATION OF DELAWARE SOUND-PROPAGATING DIAPHRAGM Application filed May 2, 1928. Serial No. 274,528.

vide a sound propagating diaphragm one portion of which will vibrate to produce sound waves of the upper portion of the musical register while another portion of the ,diaphragm vibrates to produce sound waves of the lower portion of the musical register.

One feature of the invention relates to the provision of connecting means between two portions of a sound propagating diaphragm whereby vibrations of one portion of the diaphragm will produce vibration of a differentcharacteristic in the other portion of the diaphragm.

Another feature of the invention relates to the provision of a connecting means between portions of a sound propagating diaphragm whereby sound waves of unlike characteristics propagated simultaneously from the different portions of the sound propagating diaphragm will not cause interference with their vibrations.

Other objects and features will appear from the following description in connection with the accompanying drawings in which Figure 1 is a side elevation of the present invention with a portion broken away.

Figure 2 is a front elevation of the sound propagatingdiaphragm embodying the present invention.

Like reference characters'denote like parts in the several figures of the drawing.

In the following description and claim, parts characteristic features and functions will be identified by specific means for convenience of expression, but they are intended to be as generic in their application to similar parts or equivalent construction as the art will permit.

Referring to the drawings for supporting a sound propagating diaphragm a base 10 is provided to which is securelyattached a supporting rim 11 supporting a sound propagating diaphragm. An electromagnetic unit 12 is provided, for actuating the diaphragm, supported by a cross member 18secured to the rim 11. The electromagnetic unit 12 includes an actuatingarm 14ione end of which is secured to the sound propagating diaphragm for actuating the diaphragm in response to electrical waves imparted to the electromagnetic unit 12.

For controlling the electromagnetic unit 12 in accordance with a signal wave, there 1s provided an energy responsive device 20, shown in the form of anantenna positioned to intercept radiant energy or so-called Hertzian waves. It is understood that such waves may be emittedfrom a radio broadcast station of conventional type, but as the emission of such energy forms no partof the present invention, it is thought that a detailed description thereof may be omitted herein. .The emitted energy preferably takes the form of a carrier wave of high frequency modulated in accordance with a signal current, the signal current corresponding in wave form to sound waves. The antenna 20 at the receiving station is operatively connected to a tuner 21, a ground or counterpoise 22 being-provi ded therefor. The tuner 21 may be variably adjusted so as to tune the circuits 20, 22 to the frequency of the carrier wave which it is desired to receive and a connection comprising a pair of wires 2323;extends from the tuner 21 to a detector-24 for impressing thereon electrical waves of this predetermined frequency. The detector 24 may be of any usual form for detecting high frequency energyand producing therefrom rectified or detected waves of signal frequency. 3 These signal waves are transmitted over a pair of conductors 25 extending to the input of an amplifier 26 whereby the signal energy is amplified to a desired degree. A pair of conductors 27 forms an operative connection from the output of the amplifier 26 to the electromagnetic unit 1.2. Thus undulatory current of signal frequency is impressed upon the electromagnetic unit 12 under control of received radiant energy.

For producing sound waves of both upper and lower portions of the musical register, a sound propagating diaphragm 30 is provided comprising a cone formed from fibrous material such as paper or the like, supported by the supporting rim 11, its apex being; operatively connected to the actuating arm 14:. A plurality of apertures 31 are provided dividing the cone 30 into a central cone 32 and a surrounding truncated cone 33. The apertures 31 are preferably arranged closely adjacent forming a circle of apertures of a radius approximately one fourth the radius of the cone, the distance of spacing being approximately equal to the diameter of the apertures. These apertures efiect the damping of the vibrations passing from the cone 32 to the truncated cone 33.

In the operation of the device waves of the desired frequency are selected detected and amplified by the energy responsive device 20 and are supplied to the electromagnetic unit 12 which causes oscillation of the actuating rod 14 or if desired rod 14 may be oscillated by a stylus operating on a phonographic record. Oscillations of the actuating rod 14 are imparted to the cone 30 through the connecting of rod 14 to the apex of the cone 32, which because of its so small circumference and direct attachment to the actuating arm 14 will be caused to vibrate at high frequency producing sound waves of the upper portion of the musical register. Vibrations of the central cone 32 are imparted to the truncated cone 33 through the material between the apertures 31 in the face of the cone. Thus the vibration of the truncated cone 33 will be similar to but of a lower frequency and of greater length than the vibration of the central cone 32, propagating sound waves of the lower portion of the musical register.

Thus it may be seen that the invention provides a sound propagating cone or diaphragm which will be small in size and light in weight, easy to manufacture and which will be adapted for the simultaneous propagation of sound waves of boththe upper and lower portions of the musical register.

The invention upon which this application is based is broader than the specific embodiments shown and described for the purpose of illustrating at least some of the ways in which it may be employed. The scope of the invention is therefore to be understood as not being limited by the present specific descrip-

Images