US2846915A - Adjustable bridge for stringed musical instruments - Google Patents

Description

Aug. 12, 1958 2,846,915

ADJUSTABLE BRIDGE FOR STRINGED MUSICAL INSTRUMENTS J. v. DARIA Filed May 16, 1955 INVENTOR (/AME-S KID/IBM Y Z Wionmzv United States Patent ADJUSTABLE BRIDGE FOR STRINGED MUSICAL INSTRUMENTS James Vincent Daria, Yonkers, N. Y.

Application May 16, 1955, Serial No. 508,458

4 Claims. (Cl. 84-307) This invention relates to an improved bridge for stringed instruments such as guitars, mandolins, banjos, bass violins, and the like, and the general purpose is to improve the construction of the bridge so that the effective length of each string may be independently and accurately adjusted. Preferably also, I provide means for adjusting the height or clearance of each string at the bridge as well as by means of the usual tension adjustments provided on the neck of the instrument. Such instruments, if fretted, are usually designed so that the twelfth fret is midway between the bridge and the nut, and the difference in pitch of the string when this fret is pressed and when it is released should be an octave so that in use independent adjustments of the position of the bridge is desirable for each string. In guitars, this adjustment is especially important in using harmonies. In addition, each string should be at a predetermined height above the frets and neck, so that when a string is depressed on one fret it will not strike any other fret between it and the bridge, so that harmonics may be supplied by lightly pressing a finger On a string without engaging any fret.

I have, therefore, provided by my invention an improved bridge in which not only may the position of the string engaging portion of the bridge be carefully adjusted along the string but also the height of each string at the bridge adjusted. I am aware that each of these adjustments has heretofore been individually proposed, but by my invention not only may both adjustments be made on the same bridge while retaining a simple and cheap bridge construction but the longitudinal adjustment may be made without touching or disturbing the affected string. By my invention, individual strings can be adjusted if desired and even removed and replaced without disturbing the general setting of the instrument.

Referring to the drawings in which the prefered form of the invention is shown, Fig. 1 is a perspective view of a guitar with my improved bridge thereon;

Fig. 2 is a detailed perspective view of my improved bridge;

Fig. 3 is an enlarged perspective view of a portion of the bridge;

Fig. 4 is a section taken on line 44 of Fig. 2.

A guitar to which my invention is applied is shown at 1, provided with the usual neck 2, frets 3 and string tightening posts 4. The stretched strings pass over the elevated fixed bar or nut 5 to the bridge 6 slightly above the frets so that the fingers of the player may press any string onto any fret to secure the pitch desired. Beyond the bridge the strings are anchored in a tail piece 7. It is to the bridge that my invention particularly relates.

According to my invention, I so construct the bridge that not only may the length of each string between the nut and the contact point, rest or seat on the bridge be readily adjusted but also the height of said contact point. By this two fold adjustment, not only may the ice twelfth fret be kept at the exact center of the tone-giving portion of each open string to give an octave difierence, but also the proper height above the finger board maintained for each string, thus avoiding undesired contact between a vibrating string with a fret between the bridge and the fret against which it is being held by the players finger.

In the form of the invention shown, the bridge is made of a base plate 8 secured in or on the top of the guitar and on which is adjustably mounted a platen 9 by means of threaded posts or rests 10, 10 on which nuts 11, 11' are threaded which support each end of the platen. On the platen are rotatably mounted a plurality of screw shafts 12, one for each string, each extending between and journaled in opposite, upturned edges or cars 13 extending upwardly from the two sides of the platen. On each shaft is threaded a block 14 positioned a short distance above the bottom of the platen so that it may be tilted in either direction about shaft 12 as a center.

The pin or post 15 over which the string is stretched is positioned in a lateral extension 16 from each block, and the block is tilted about its shaft 12 by means of a set screw 17 threaded in said extension and bearing at bottom on the platen. Slots 12 may be provided in the heads of shafts 12 and set screws 17 for a screw driver and also in posts 15 to guide the string. Preferably screw 17 has an Allen type socket head. In Fig. 3 the block 14 has been tilted further counterclockwise than block 14' to raise the left-hand string. To change the effective length of a string, all that need be done is to rotate shaft 12 to adjust block 14 and with it the position of its contact post or rest lengthwise of the string. The shaft is held against end play and vibration by locknut and washer 1?. Each adjustment is independent of the other but preferably the lengthwise adjustment is made first because a lengthwise adjustment will vary slightly the height of the string. When both adjustments are made, the position of the post will remain fixed until readjusted. Posts 15 may be made readily removable from their blocks 16 so that they may be replaced when worn or when the owner desires to use a post of different material to vary the tone.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It may be noted that according to my invention, the height of each individual string can be adjusted without touching or otherwise disturbing the string since the height adjustment is secured by screws 17 spaced from and independent from the rests 16 over which the strings pass.

What is claimed is:

1. In the combination of a bridge assembly and a stringed instrument having a body portion and at least one taut string which is anchored at opposite ends to the instrument and extends longitudinally over the body portion, wherein the bridge assembly includes a base member mounted atop the body portion and an elongated plate surmounting the base member in transverse relation to and below the string; a pair of aligned longitudinally spaced ears upstanding integrally from the plate and spaced laterally of the path of the string, a threaded shaft journalled at its end-s for rotation in the ears and extending in parallel spaced relation to the string, a block member axially threaded upon the shaft and adapted to ride along the shaft in one direction or the other accordingly as the shaft is rotated clockwise or counterclockwise, a stepped down shoulder extending from the block transversely of the underside of the string, a post projecting up from the shoulder having a trackway defining a seat for and parallel to the string whereby the seat is caused to ride longitudinally relative to the string as the shaft is rotated, and a set screw threaded through the shoulder having a bottom projecting end in abutment with the plate, the set screw being threadable in the block whereby the block is adapted to be moved angularly on its shaft in a vertical plane so as to press or relax the seat of the post against the string accordingly as the screw is threaded inwardly or outwardly of the shoulder.

2. In the combination as in claim 1, wherein the threaded shaft is characterized by a head at one end adapted to accommodate a screw driving tool, and by lock nut means at its opposite end cooperable with the adjacent ear for locking the shaft in a selected rotated position.

3. In the combination as in claim 1, wherein the post supporting the string is interchangeable with similar posts of other material whereby the total effects of the associated string may be selectively varied according to the material composition of the post.

4. in the combination of a stringed instrument having a body portion and a plurality of taut strings extending longitudinally over the latter, and a bridge assembly for the strings including a base member mounted atop the body portion and an elongated plate surmounting the base member in transverse relation to and below the several strings; a plurality of string supports arranged upon the plate, one for each string, wherein each support comprises a pair of aligned longitudinally spaced ears upstanding integrally from the plate and spaced laterally of the path of an associated string, a threaded shaft journalled at its ends for rotation in the ears and extending in parallel spaced relation to the string, a block member axially threaded upon the shaft and adapted to ride along the shaft in one direction or the other accordingly as the shaft is rotated clockwise or counterclockwise, a stepped down shoulder extending from the block transversely of the underside of the string, a post projecting up from the shoulder having a trackway defining a seat for and parallel to the string whereby the seat is caused to ride longitudinally relative to the string as the shaft is rotated, and a set screw threaded tlrrnugh the shoulder having a bottom projecting end in abutment with the plate, the set screw being threadable in the block whereby the block is adapted to be moved angularly on its shaft in a vertical plane so as to press or relax the seat of the post against the string accordingly as the set screw is threaded inwardly or outwardly of the shoulder.

References Cited in the file of this patent UNITED STATES PATENTS 2,491,788 Widowson Dec. 20, 1949 2,573,254 Fender Oct. 30, 1954 2,740,313 McCarthy Apr. 3, 1956 FOREIGN PATENTS 82,426 Norway Sept. 14, 1953

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