US1485155A

US1485155A - Banjo resonator

Info

Publication number: US1485155A
Application number: US562782A
Authority: US
Inventors: Albert M Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1922-05-22
Filing date: 1922-05-22
Publication date: 1924-02-26
Anticipated expiration: 1941-02-26

Description

Feb. '26, 1924. 1.485,l55

A. M. ANDERSON BANJO RESONATOR Filed Iggy 1.922

Patented Feb. 26, 1924.

UNITED STATES ALBERT M. ANDERSON, OF SEATTLE, WASHINGTON.

BAN J O RESONATOR.

Application filed May 22, 1922. Serial No. 562,782.

7 '0 all whom it may concern:

Be it known that I, ALBERT M. ANDER- SON, a citizen of the United States of America, and resident of the city of Seattle, in the county of King and State of VVashington, have invented certain new and useful Improvements in Banjo Resonators, of which the following is a specification.

My invention relates to an. attachment in the form of a resonator for banjos, mandolin-banjos, and like musical instruments which have a stretched head and a rim which is open at its under side.

The object of my invention is to provide a resonator which will considerably increase the volume of sound produced from the instrument with like playing effort, and to mellow and soften the tone thereof.

In accomplishing this object I provide means whereby the original sound waves are divided and led off, and thus are not reflected back towards the vibrating head to interfere with other subsequent sound waves.

My invention is embodied in the novel attachment or resonator which is shown in its present preferred form in the accompanying drawings. I

Figure 1 is a transverse section taken on the central line of the banjo and resonator.

Figure 2 is a plan view of a banjo with the resonator attached.

Figure 3 is a detail section showing the means of attaching the resonator to the banjo.

The banjo comprises the rim 11, the stretched. head 1, and strings 12 supported by a bridge 13 and extending to the outer end of a stem 14. To this banjo I attach a resonator in some suitable manner, the attaching means being unimportant. The resonator comprises a bowl-like shell designated generally by the numeral 2. The attaching means which I have shown comprise a plurality of brackets 20 which are secured to the resonator and which frictionally engage the outer periphery of the banjo rim 11. It will be apparent that any other suitable securing means may be employed.

The shell 2 lies beneath the open side of the banjo. At about the center of the head 1 it rises to a conoidal peak 21. The peak 21 is preferably beneath the playing center or center of vibration of the banjo head. This may or may not be atexactly the cen ter of the circular head 1, but will be sub stantially at this .point, and therefore for most players and most instruments centrally positioned peak 21 is preferable. From the peak 21 the resonator extends downwardly in all radial. directions in a smooth curve. Preferably it is provided with a rim 22. The surface 223 between the rim 22 and the peak 21 is formed as a curve which merges into both the rim and the peak. The rim is notched as indicated at 24- to receive the heel of stem 14. Preferably this heel does not touch the edges of the notch 24.

The sound waves inwardly projected from the banjo head strike the resonator or deflector and by reason of its curved shape are deflected outwardly in all directions from the peak 21 and forwardly through the annular opening between the resonator rim 2 and the banjo rim 11, thus adding to and reinforcing the sound waves which are originally projected outwardly. Vibrations are also induced in the resonator in harmony with those given off by the banjo. It acts both as a deflector and as an amplifier of the sound.

It is essential that the peak be provided in the resonator because if this is omitted the sound waves will merely be reflected back and forth between the resonator and the head 1 and interference will result. By providing an open sound conduit extending from the central peak in all directions about the rim 11 of the banjo, and curved to prevent direct reflection, the sound waves are led outward and do not interfere with additional waves originating in the head 1. This is the essence of my invention and while the general curve of the resonator may be varied and while the rim 22 might be omitted, it is essential that the peak 21 be provided and that it be positioned substantially beneath the center of greatest vibration of the head 1. I

What I claim as my invention is:

1. A resonator for banjos comprising a shell adapted to cover the open back of the banjo, and means for attaching the shell to a banjo, the surface of said shell which faces the banjo head sloping from a sharp central point towards its periphery in all directions by a curve of a radius at least substantially equal to the radius of the banjo.

2. A resonator as in claim 1, the attaching means comprising frictionally engaging inturned lugs spaced about the periphery of the shell.

3. A resonator for banjos comprising a bowl-like shell adapted to cover the open back of the banjo, and of greater diameter than the banjo, said shell including a rim formed about its periphery and extending about the rim of the banjo, and directed for wardly, the surface of said shell which faces the banjo head sloping from a sharp central point in all directions to merge with the rim by a curve of a radius at least substantially equal to the radius of the banjo, and means for attaching the shell to a banjo.

i. A resonator as in claim 3, said attaching means comprising members spaced about and secured to the inner surface of the rim only, and engageable with the banjo rim.

5. In combination with a banjo or like musical instrument, a resonator comprising a bowl-like shell of slightly larger diameter than the banjo head, and including a peripheral rim extending about and spaced from the banjo rim, and a sharp substantially centrally positioned peak upon the inner surface of the shell, said shell forming with the banjo a sound chamber curving from said peak downward and outward in all radial directions by a curve of radius at least substantially equal to the radius of the banjo, and then upwardly outside of the banjo rim.

6. A resonator for banjos and like musical instruments comprising a b0wl-like shell having a marginal rim and a sharp central peak, the surface between the rim and peak being formed on a curve which is concave in cross section towards the banjo at all points, and which merges into both peak and rim.

7. A resonator for banjos and like musical instruments comprising a substantially circular shell having a sharp central peak, the surface between the periphery and peak being formed on a curve which is concave in cross section tow: rds the banjo at all points, and the center of curvature of which follows a circle lying towards the periphery of the resonator from an axis extending through its center.

Signed at Seattle, Kinp County, ashiugton, this 16th day of l\ ay 1922.

ALBERT M. ANDERSON