US2323969A - Stringed instrument - Google Patents

Description

July 13, 1943. c. BIEDERMAN 2,323,969

STRINGED INSTRUMENT Filed April 28, 1942 FQ'J.

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INVENTOR ATTORNEYS Patented July 13, 1943 UNITED STATES PATENT OFFICE 2,323,969 STRINGED INSTRUMENT Clarence Biederman, Lima, Ohio Application April 28, 194,2,v Serial No. 440,836

3 Claims.

The present invention relates to improvements in stringed musical instruments and more particularly to means for varying the tension of the strings thereof.

An object of the invention is to provide a string tension varying device of generally improved design.

Another object of the invention is to provide a device of the aforesaid character wherein the tension of one or more strings may be varied upon movement of a single operating element.

A further object of the invention is the provision of a device of the above character which is relatively simple in construction and which may be quickly and easily operated.

Other objects and advantages of the invention will become apparent as the description progresses.

In the accompanying drawing forming a part of this speciiication and in which like numerals are employed to designate corresponding parts throughout:

Figure l is a fragmentary plan View of a stringed instrument showing the invention applied thereto,

Figure 2 is a side elevational View ofthe same,

Figure 3 is an enlarged section taken on line 3 3 of Figure 1 with the operating handle in raised position,

Figure 4' is a transverse on line 4 4of Figure 3,

Figure 5 is a section taken on line 5 5 of Figure 3, and

Figure 6 is a section viewed from line 6-6 of Figure 3 with the cover in separated relation.

Referring in detail to the drawing, wherein for the purpose of illustration is shown a preferred example of the invention, I6 generally designates a stringed instrument, in the present example an electric Hawaiian guitar, having strings II, I2, I3, I4, I5 and I6 extended to the rear end of the body or sound box.

To the rear end of this instrument I@ is fastended a channel-shaped support bracket I'I which may be formed of sheet metal providing a pair of complementary elongated side plates I8 arranged vertically of the instrument and projecting above the top of the sound box. Between the plates I8 is provided a vertical web portion I9 having top and bottom portions bent inwardly to form flanges 2G and 2I disposed against the top and bottom of the instrument, as shown to advantage at Figure 4, The web porion I9 and the bottom flange 2| may be rmly secured to the instrument body by screws sectional view taken 22 while the upper angular portion of the web is preferably shaped to form an outwardly protruding transverse lip 23. Adjacent the top edge of each side plate I8 is provided a transverse slot 2d opening into the outer edge while the bottom portion is cut out to provide an angular recess 25.

Journaled on and extending transversely between the side plates i8 is a rotary member 26 in the form of a cylindrical elongated barrel formed at the ends with reduced journals 2l adapted to be rotatably extended through the bearing slots 24, The barrel 26 is shaped to provide, at axially spaced intervals, a plurality of` circumferential grooves 2S extending partially about the barrel to form cam portions or sections having arcuate segments of an exterior radius corresponding to the radius of the barrel and segments of reduced radius, shown to advantage at Figure 6, the proles of these cam sections varying as to the extent of the reduced grooved portions and as to the circumferential arrangement thereof, as best shown at Figure 3.

Supported on and extending between the side plates i8 below and inwardly of the barrel 26 is a shaft 29 parallel with the barrel and of smaller diameter. This shaft 29 supports thereon a plurality of rocker elements 3U of L-shaped formation having right angular arms and provided with transverse bores 3I at the juncture of the armsfor rocker mounting on the shaft 29. These rocker arms are spaced on the shaft by means of sleeves and spacing collars 32 and 33 respectively, tov assume predetermined coacting positions with relation to the grooved cam sections oi the barrel. In the embodi ent shown, a plurality of rockers 36 are formed so that the right angular arms are of approximately uniform width. One of the rocker elements indicated at S15 is shaped so that one arm thereof is enlarged to form a lateral extension 35. The upper end portions of the upstanding arms of the rocker elements are formed with apertures 36 designed for connection therewith of one end of certain strings of the musical instrument, The opposite, approximately horizontal, arm of each of the rocker elements 36 is formed with an interiorly threaded aperture E6' adapted to receive therein a screw 3'! which is adjustable transversely of the arm and which may be secured in adjusted position by a nut 3S. The rocker element 34 carries two of the adjustable screws 3i in spaced relation, as illustrated at Figure 3.

To the protruding end of each of the journais 2 is secured the inner end of a radially disposed arm 39, these arms being disposed for connection with the ends of a transverse bar lill forming an approximately U-shaped handle for turning the barrel.

On the support member I'! is normally positioned a cover il embodying a pair of end plates 2, corresponding to the end plates I8, connected ,by a top wall 43 and an outer wall 44. In the upper portions oi the plates 42 are provided slots i5 adapted to be slidably tted over the journals 2 when the cover is in closure position, as shown in Figures 3 and 4. The cover is removably fastened on the holder bracket by means of screws i5 engageable with registering apertures ll'! in these elements.

In the example illustrated, the instrument I is equipped with six strings, the string Il of which has its rear end or terminal secured in xed position to the instrument, as shown to advantage at Figure 1, while the remaining ve strings are extended rearwardly for connection with the respective rocker elements and 34. The inner or upper ends of the adjusting screws 3'! on the rocker elements project from the arms for engagement with the cam sections of the barrel so that upon arrangement of the barrel in varying angular positions the screws 3'! will assume registration with the protruding or the recessed grooved portions of the cams. In the arrangement shown, when the operating handle i8 is in uppermost position with the arms 39 thereof disposed vertically, five of the cams will be disposed so that their portions of greatest radius will contact with the screws 3'! of the rocker elements to dispose said elements in such arrangement that the strings l2 to I6 inclusive, will be under greatest tension. If the barrel is rotated in a clockwise direction through an arc of ninety degrees it will attain a positi-on, with the handle extending rearwardly, as shown at Figures 1 and 2, wherein the inner ends of the screws 3'! can enter the grooves 28 under the tension of the strings and thereby decrease or slacken the tension and change the pitch of the strings. When the rockers are thus related to the barrel the upstanding arms thereof may be disposed to bear against the lip 23 of the holder. When the handle is swung to a third position, downwardly with relation to the holder, as shown in dotted lines at Figures 2 and 4, the screws of certain of the rockers will remain in the grooves so that certain of the strings such as the strings I3 to I6 remain slackened. Due to the arrangement of the barrel groove in coacting relation with the adjusting screw in the 01T- set portion of rocker 34, however, the screw of this rocker will be depressed by the cam so as to restore the string l2 to a condition of increased tension.

In each of the respective tuning positions of the cam member or barrel, which are attained 4by selective movement of the handle, a plurality of strings of the instrument are tensioned to effect a predetermined tuning or chord. In addition to various tuning combinations obtainable upon angular adjustment of each barrel, further tuning combinations can be made available by interchanging barrels on the holder bracket. It

will also be apparent that the invention is applicable to stringed instruments of various forms and having a varying number of strings.

It is to be understood that the form of my invention herewith shown and described is to be taken as a preferred example of the same and that various changes relative tc the material, size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope `of Ithe subjoined claims.

Having thus described my invention, I claim:

l. In a tensioning device for a musical instrument having a plurality of strings, a support adapted for attachment to the instrument, a plurality of angular rocker elements pivotally mounted on the support to rock in the direction of the strings, a projection carried by each rocker element, means at one end of each rocker for engaging a string, a barrel pivotally mounted on the support parallel with the pivot axes of the said rocker elements, the said barrel having a plurality of circumferential cam forming sections against which the projections ofthe respective rocker elements are held by the tension of the strings, and means attached to the barrel for turning the same to vary the tension of the strings.

2. In a tensioning device for a musical instrument having a plurality of strings, a support adapted for attachment to the instrument, a plurality of angular rocker elements pivotally mounted on the support so as to rock in the direction of the strings, an adjustable projection carried by each of the rocker elements, each of the said rockers having one end adapted for engagement with a string, a barrel pivotally mounted on the support parallel with the axes of the said rockers, the said barrel having a plurality of circumferential arcuate grooves at longitudinally spaced intervals coacting with corresponding arcuate portions of the barrel surface to provide cam sections against which the projections of the respective rocker elements are' pressed by the tension of the strings, and means attached to the barrel for selectively turning the same to vary the tension of the strings.

3. In a tensioning device for a musical instrument having a plurality of strings, a support adapted for attachment to the instrument, a plurality of angular rocker elements pivotally mounted on the supportso-as to rock in the direction of the strings, an adjustable projection carried by each of the rocker elements, each of the said rockers having one end adapted for engagement with a string, a barrel pivotally mounted on the support parallel with the axes of the said rockers, the said barrel *having a plurality of circumferential arcuate grooves at longitudinally spaced intervals coacting with corresponding arcuate portions of the barrel surface to provide cam sections against which the projections of the respective rocker elements are pressed by the tension of the strings, and a U-shaped handle having connection with the ends of the barrel for selectively turning the latter to vary the tension of the strings.

CLARENCE BIEDERMAN.

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