US2491991A

US2491991A - Bridge for stringed instruments

Info

Publication number: US2491991A
Application number: US760141A
Authority: US
Inventors: Lundback Per Gustav Folke
Original assignee: Lundback Per Gustav Folke
Priority date: 1946-01-08
Filing date: 1947-07-10
Publication date: 1949-12-20
Anticipated expiration: 1966-12-20

Description

Dec. 20, 1949 P. e. F. LUNDBACKY 2,491,991

BRIDGE FOR STRINGED INSTRUMENTS Filed July 10, 1947 2 Sheets-Sheet 1 pwywmw Dec. 20, 1949 LUNDBACK. 2,491,991

BRIDGE FOR STRINGED INSTRUMENTS Filed July 10; 1947 2 Sheets-Sheet 2 n 6. 70 IO Patented Dec. 20, 1949 UNITED STATES PATENT OFFICE Sweden January 8, 1946 Claims. (Cl. 84-307) The bridges used particularly in lutes, guitars and similar stringed instruments have been very diflicult to fit in. Furthermore, instead of accommodating themselves to the cover of the instrument, they have more or less deformed said cover, and also changed and, as a rule, deteriorated the acoustic properties of the instrument.

The bridge according to the invention, which in accordance with one embodiment contains a longitudinal member supporting the cords, is substantially characterized by the fact that under each of the feet of the bridge is provided a supporting block resting against the cover of the instrument and that between each supporting block and the bridge is provided an adjusting device.

In one of the embodiments of the bridge each adjusting device consists of a screw on to which is screwed a nut, disk or the like controlling the displacement of the longitudinal member and resting against the lower side of the member. Of course the screw may also be screwed directly into the longitudinal member from below whereby said member may be raised or lowered by turning the screw relatively to said member, but this arrangement is not particularly preferred since it makes the adjustment of the bridge more troublesome. Each screw preferably may be provided with a convex head adapted to bear against the bottom of a recess made in the respective supporting member. If the screw is provided with the nut indicated above, the screw head should be provided with an edge-shaped projection adapted to enter the bottom of the recess of the supporting member and to prevent a movement of the screw relatively ot the supporting member.

On its lower side each supporting block may also be provided with three projections or three supporting portions adapted to rest against the cover of the instrument. By this arrangement a uniformly distributed contact pressure is obtained. Furthermore, each screw should be provided with a locking device for fixing the screw in the adjusted position relatively to the longitudinal member, e. g. a nut adapted to be screwed on to the upper end of the screw and to be pressed against said longitudinal member.

The bridge according to the invention may also have three triangularly placed feet. Preferably, one, two or all of the feet are provided with elevation adjusting devices, by means of which the respective foot may be elevated or lowered and the bridge be adjusted to different positions relatively to the cover of the instrument.

In another suitable embodiment of the invention, by which a very uniform and firm contact is obtained, supporting blocks may be provided under one, some or preferably all of the screws, said blocks being adjustable relatively to the screws and adapted to automatically adjust themselves in accordance with the cover when pressed against the cover. On its lower side each supporting block should be provided with three triangularly placed projections or supporting portions adapted to rest against the cover of the instrument, whereby, in case there are three blocks the pressure of the bridge is uniformly distributed in no less than nine points.

The invention is illustrated by way of examples in the accompanying drawings, in which:

Fig. 1 shows one embodiment of the bridge mounted on the cover of an instrument.

Fig. 2 is a vertical section through one adjusting device of the bridge, and

Fig. 3 is a plan view of said adjusting device.

Fig. 4 shows a second embodiment of the invention, in which the bridge also is located on the cover of an instrument, one supporting block being shown in vertical section.

Fig. 5 is a view from below of a supporting block.

Fig. 6 shows the bridge according to a third embodiment viewed in the longitudinal direction of the cords and partly in section.

Fig. 7 is a plan view of the bridge, and

Fig. 8 show-s a supporting block viewed from below.

I designates the cover of the instrument against which two supporting blocks 3 rest. In each of said blocks is provided a recess 4 against the spherical bottom of Which the head 6 of a screw 5 bears. Each screw head is provided with an edgeshaped projection 1 adapted to be pressed into the bottom of the recess 4 and to make impossible a movement of the screw 5 relatively to the block 3. The upper end portions of the screws enter with some play recesses or sleeves which are made in, or rigidly connected with a longitudinal member 2 supporting the cords. Annular nuts 8 which are screwed on to the screws 5, rest against the lower side of said member.

In the above mentioned bridge the blocks 3 will lie close on the cover I of the instrument and adjust themselves freely in accordance with the shape of the cover. By means of the nuts 8 it is possible to adjust the member 2 to the desired position relatively to the cords, the screws 5 assuming automatically the supporting positions conditioned by the positions of the member 2 and of the blocks 3. It being possible to fit the supporting blocks 3 in such manner that the member 2 always rests close on the nuts 8, it will be very easy to adjust the member 2 without the latter being subjected to any breaking or bending strain. The bridge according to the present invention involves a considerable saving of material in comparison with the known bridges. Thus, the present bridge is cheaper to manufacture and, due to the reduction of the weight, the bridge also damps less than the old bridges.

As Will be seen from the drawing, each supporting block 3 is provided with three supporting portions 9 adapted to rest against the cover I of the instrument in the embodiment according to Figs. 4 and 5. Furthermore, the screws 5 supporting the longitudinal member 2 by means of the nuts 8 are of such length that nuts i may be screwed on to the upper ends of the screws, said nuts fixing firmly the member 2 in its adjusted position by the nuts contacting the upper side of the member 2. A bridge constructed according to this embodiment will rest against the upper side of the cover with a pressure uniformly distributed in six points, and in spite of the firm connection between the screws and the member 2 the supporting blocks can adjust themselves freely in accordance with the shape of the cover.

In Figs. 6 8 it is also shown that the bridge 2 is provided with a projection H formed from the bridge. A screw 5 passes through said projection and through each of the end portions of the bridge. Each screw is provided With a nut 8, said nuts carrying the bridge. The bridge can be raised or lowered by turning said nuts. The heads of the screws rest in recesses made in supporting blocks 3. On its lower side each block is provided with three supporting portions 9 adapted to rest against the cover I of the instrument. Thus, in the construction in question the bridge will support against the cover in nine points. The screws '5 have been given such length that nuts l0 can be 'screv'v'e'd on to their upper ends, said nuts fixing firmly the members in the adjusted position by resting against the upper side of the bridge 2 and against the projection I l respectively.

Other embodiments not illustrated in the drawing are of course possible within the scope of the invention. For example, the screw 5 may be fixed to the blocks 3 and provided with a sleeve having a nut and adapted to be screwed on to the sleeve. The member supporting the cords is adapted to rest adjustably against the upper portion of said sleeve. Furthermore, the bridge may consist of a number of supporting members between which is glued the member supporting the cords, said member preferably consisting of two joined parts. Ihe supporting members may also be fixed, if desired adjustably, to the screw 5 in a suitable angle in relation to the centre axis of the screw. Furthermore, when the bridge is provided with three feet, said feet may be made stationary and, ii desired, support directly against the cover of an instrument.

Having now described my invention, what I claim as new and desire to secure by Letters Patent:

1. A bridge for stringed musical instruments, said bridge having at least three angularly spaced instrument-contacting surfaces, of which at least one comprises a foot member articulatedly connected to said bridge.

2. A bridge for stringed musical instruments, said bridge having at least three angularly spaced instrument-contacting surfaces, of which at least one comprises a foot member articulatedly connected to said bridge and being by elevation means adjustable to height.

3. A bridge for stringed musical instruments, having fo'ot members articulatedly connected thereto, each of said foot members comprising a. body having three triangularly spaced support ing points resting on the instrument cover.

4. A bridge for stringed musical instruments, having foot members articulatedly connected thereto by means of elevation adjusting means, said elevation adjusting means comprising screws articulatedly mounted on said foot members, each screw being provided with an adjustment nut, screwed on thereto, on which the bridge rests, and also a binding nut preventing inadvertent adjustment of the bridge.

*5. A bridge for stringed musical instruments having three foot members triangularly spaced under the bridge, each of said foot members comprising a body articulatedly connected to the bridge by elevation adjusting means and having three triangularly spaced supporting points resting on the instrument cover.

PER GUSTAV FOLKE LUNDBACK.

REFERENCES CITED The following references are of record in the file 'of this patent:

UNITED STATES PATENTS