US1746377A - Loud-speaker - Google Patents

Description

Feb. 11, 1930. R. A. BEAUSEJOUR 1,746,377

LOUD SPEAKER Filed Jan. 18. 1927 2 Sheets-Sheet 1 INVE/V 70/? 2 P5015 351 70550006 Feb. 11, 1930. r R. A. BEAUSEJOUR 1,746,377

LOUD SPEAKER Filed Jan. 18. 1927 2 Sheets-Sheet 2 flxqfi- I I I Patented Feb. 11, 1930 UNITED STATES REME A. IBEAUSEJOUR, PORT RICHMOND, NEW YORK LOUD-SPEAKER Application filed January 18, 1927. Serial No. 161,731.

This invention relates to radio apparatus and particularly to that type thereof known as loud speakers.

Devices of this type as heretofore constructed are characterized bythe use of either a sounding body consisting primarily of a confined sounding air column or a relat vely thin, flexible member with which the vibrator ofatelephone unitis directly connected for causing the vibrations of such unit produced by the changes in audio-frequency waves, to be transmitted to the atmosphere in the first case through the sounding air column and 1n the second case through or by means of flexible members. In either case the relatively small movement of the vibrator is impressed upon a medium or member, the nature of which is such that it offers but slight reslstance to distortion under the influence of the almost. infinitesimal amount of mechanlcal energy exerted by the movement of the actuatin member of the telephone unit.

Vt hile the above types of loud speakers give fairly satisfactory results the prmclpal objections thereto are that their reproduction is fuller and urer for notes of certain frequencies than or other notes, and that, due to resonance, false notes or tones are frequently produced.

The principal object of the present invention is to rovidea new and improved construction or a loud speaker b means of which notes andtones of great c arity, pureness and volume may be secured.

Another object is to provide a new and 1mproved device of marked simpliclty, and, therefore, low cost of construction.

Considered more specifically, another object of the present invention is to provide a device which will enable a telephone unlt to be attached or associated with the sounding board of a piano in such a way that the latter is employed as the sounding body or medium. 1

These and'other objects w ll appear more fully from the following more detailed description and by reference to the accompanying drawings forming a part hereof and wherein Fig. 1 is a plan view of the sounding boardof a piano having associated therewith vention; Fig. 2 is an enlarged plan view of the device; Fig. 3 is an end elevation and Fig.

4 a side elevation, parts of the piano in the latter two figures being shown in section.

As shown in the drawing, the device consists of a bracket member 10, preferably constructed of non-magnetic material as, for example, aluminum. The bracket in the constructional example illustrated consists of a supporting or plate section 11 which projects laterally from, and preferably formed integrally with, a clam section, the latter consisting of a' pair 0 C-clamp members 12. The C-clamp members 12 are so designed and proportioned that they are adapted to straddie the web portion 13 of the string plate 15 of the piano. The plate portion 11 of the device is provided with a plurality of apertures through which adjusting screws 16 are adapted to pass, said adjusting screws serving to support a telephone unit 17 and being provided with lock nuts 18 for holding the unit 17 in adjusted position. I'have shown in the drawings, and prefer to em loy, three 7 such screws 16 in order to .pr'ovi e a tripod adjustment.

The plate is furthermore provided with apertures for the reception of screws 19 which are clamped securely in position to the plate 11 by means of lock nuts 20; the ends of such screws projecting downwardly and serving as binding posts and being provided with the usual knurled nuts 21 which serve to secure the ends of terminal wires to said binding post.

The tele hone unit 17 which may be of any suitab e construction has secured to its vibrator a pin 22; said pin passes through an aperture in the plate 11 and its lower end rests, in the particular constructional examle illustrated, in a small depression 23 ormed in the bridge 24 of the piano sounding board 25. Clamping screws 26 are angagcd Within the C-clamp sections 12 for e5 clamping the device securely in position upon the piano. In some cases it may be desirable to provide a bushing 27 through which the pin 22 passes.

The device may be secured atany suitable point to the string plate, but preferably is secured a proximately at the polnt indicated by the re erence character A in Fig. 1, so that the pin 22 will be engaged with the bridge of the sounding board substantially midway of the length thereof. If it is desired to use the attachment with the pin 22 in contact with the sounding board of the piano directly and not with the bridge thereof, the device may, for example, be secured at the point indicated by the reference character B in Fig. 1 of the drawing.

The manner'in which the device is used is as follows:

The C-clamp portions 12 are placed over one of the webs 1:? of the string plate of a' piano at the desired point, preferably so that A the pin 22 will rest on the string bridge approximately centrally thereof. The screws 26 then are tightened to hold the bracket 10 securely in position. After this the unit 17 with the pin 22 carried thereby is adjusted to bring the pin properly in contact with the bridge; a slight depression such as made by a center punch being first made for the lower end of the pin to rest in. The ends of the terminal wires leading to the amplification stages are then connected to the binding posts 20, 21, and the device is ready for use. No drilling of holes in the sound board or the alteratlon of any other part of the piano are required, as the C-clamp portions of the bracket are merely tightened uponthe existing webs of the metal string plate.

Although the pin 22 is'brou ht into engagement with the thick, rigid ridge piece and is not permanently secured thereto, the use of the device has produced the surprising and unexpected results of transmitting the relatively small mechanical energy of the vibrations of the diaphragm of the telephone unit through the small pin 22 to the comparatively rigid, heavy, bridge piece and sounding board, so that the latter is vibrated in unison with the tele hone unit to reproduce the original sound; broadcasted not only with great volume but also with remarkable clearness, fidelity and purity.

The vibrations corresponding to any particular tone or note evidently are transmitted through the bridge piece to the particular section of the sounding board, the fundamental tone of which section corresponds most nearly to the note being reproduced. The use of the device has demonstrated that, for example, vocal sounds, either singing or speech are reproduced as clearly and with as great purity as piano or other instrumental music. In the reproduction of instrumental music with my improved device, the notes of brass instruments are as distinctive as those of the piano and there is no confusion or interference with the reproduced sound of characteristically piano notes such as might be expected to be produced as, for example, by

vibration of the piano strings induced by resonance effects.

The volume of sound may bevaried by 1. The combination with a piano having.

a sounding board, a string bridge and a string plate, the latter being provided with strengthening webs, of a bracket adapted to be secured to one of said webs, a telephone unit carried by said bracket, and means to cause said sounding board and unit to vibrate in unison comprising a pin connected at one end with said unit, said string bridge being provided with a depression in which the other end of said pin is freely seated.

2. The combination with a piano having a sounding board, a string bridge and a string plate, the latter being provided with strengthening webs, of a bracket adapted to besecured to one of said webs, said bracket being provided with a supporting plate portion and a clam portion, the latter serving to secure the brac et to one of said strengthenmg webs, a telephone unit secured to said supporting plate and a member havin one end thereof secured to said unit and its other end pressed into contact with said string bridge.

3. In a device of the character set forth, a bracket having a supporting plate portion and a clamp portion, the latter being adapted to be secured to a piano, a telephone unit secured to said plate portion, and a member connected with said unit and adapted to be held in free engagement either with the sounding board or string bridge of a piano.

4. In a device of the character set forth, a bracket of non-magnetic material, clamping means associated with said bracket for clamping it to a piano, a telephone unit supported by said bracket adjacent to, but spaced from the strings, bridge piece and sounding board of a piano, 2. pin having its one end connected with said unit and its other end adapted to be operatively associated with the sounding board of a piano for causing said sounding board to be vibrated in unison with said unit, and means for securingsaid unit to said bracket, said means includin devices for adjusting the position of sai other end of said pin relatively to said sounding board.

5. In a device of the character set forth,

a bracket of non-magnetic material, clamping means associated with said bracket for clamping it to a piano, a telephone unit sup- 5 ported by said bracket adjacent to, but spaced from the strings, bridge piece and sounding board of a piano, a pin having its one end connected with said unit and its other end adapted to be operatively associated with the 10 sounding board of a piano for causing said sounding board to be vibrated in unison with said unit, and means for securing said unit to said bracket, said means including tripod adjusting devices between said unit and 15 bracket for varying the position of said unit and pin relatively to said sounding board.

In testimony whereof I have hereunto set my hand.

REME A. BEAUSEJOUR.

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