US1932975A - Stringed musical instrument - Google Patents

Description

Oct. 3l, 1933- H; KuHRMEYr-:R

STRINGED MUSICAL INSTRUMENT Original Filed April '7, 1930 Patented ct. 31, 1933 UNITED STATES PATENT OFFICE Application April 7, 1930, Serial No. 442,123 Renewed March 2, 1933 25 Claims.

The present invention relates to improvements in stringed musical instruments, such, for example, as banjos, ukuleles, etc., and has particular reference to a new and improved mounting for the finger board on the body.

In stringed musical instruments such as the foregoing, the strings are tensioned between a tail piece which is secured to one side of an annular body rim, and the free remote end of a neck which is attached to and extends radially from the rim at a point directly opposite the tail piece. The top of the neck lies substantially in the plane of the upper peripheral edge of the rim, and is provided with a plurality of frets. The strings are normally maintained out of Contact with the neck and body by means of a bridge supported on a head stretched across the peripheral edge of the rim. Each of the several strings accordingly describes two acute angles with the common plane of the neck and rim, with the apexes of these angles at the respective points of attachments of the ends of the strings to the instrument. The maximum permissible divergence of the strings from the frets is practically limited by the extent to which the musician can readily depress any particular string against the tensile effect produced as an incident to its being tuned.

The tension of the several strings introduces a compressive strain of considerable magnitude in the neck and body of the instrument and the presence of the bridge with the resulting angular relation between the strings and the common plane of the neck and body produces an accompanying bending moment whose tendency is to bow or arch the entire instrument. Because of its relatively light construction, the bending effect is most pronounced in the neck and results in warping that member in an arc whose degree of curvature reaches a maximum at the pointof attachment kof the strings and progressively diminishes toward the point of attachment to the body. As a consequence, the separation of the strings from the frets progressively increases as the instrument is used, and, due to arching tendency of the neck, reaches its.

greatest extent toward the point of attachment of the neck to the rim or body. Eventually it becomes difficult to press the strings into contact with the frets so as to utilize their intermediate lengths.

Heretofore it has been common practice to compensate for this inherent characteristic by pivotally adjusting `the neck about a point on the peripheral surface of the instrument body.

It will be apparent however that a relatively great pivoting movement of the extremity of the neck about its inner end Will be necessary in order to correct the effect thusA produced. Pivoting the neck about a point on the surface of the rim has, therefore, been an unsatisfactory expedient requiring a wide degree of manipulation to produce a .corrective effect.

It is accordingly a primary object of the present invention to adjustably secure the neck of a stringed instrument to the body by means which permits pivotal movementk of the neck about a point intermediate its respective ends thus causing a translating movement of the abutting end relative to the plane of the rim.A

It is a further object of the invention to secure the neck to the rim by means adapted to distribute the compressive stresses produced by the strings to a point in the periphery of the rim diametrically opposite the point of attachment with the neck. y

Another` object is to provide means to effect adjustment of the neck and its restoration to rigid relation with respect to the rim which is simultaneously effective to communicate com pressive stresses to a diametrically opposed point in the rim.

Another object is to provide a construction such that the compressive stress induced by the tension of the strings is counteracted by a plurality of connected members which are effective to form a closed force polygon.

A more specific` objectV is to provide an adjusting means for the neck of a stringed musical instrument which is simple, inexpensve, and capable of easy and quick manipulation.

y In the accompanying drawing:

Figure 1 is a fragmental top elevation of a preferred form of the invention as applied to a banjo.

Fig. 2 is a vertical sectional view taken line 3 3 of Fig. l.

Fig. 3 is a view similar to Fig. 2 but showing the neck in a different position of adjustment.

Fig, 4 is an enlarged detail sectional view.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawing and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed but intend to cover all modifications and f alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawing, the

along y preferred embodiment of the invention is incorporated in a banjo having a body or rim denning a peripheral edge 11 over which a head or skin (not shown) is adapted to be stretched. A neck 12 is secured to, and extends radially from, the external peripheral surface of the rim 10 with its upper surface 13 substantially in the plane o1 the peripheral edge of the rim.

A plurality of strings (not shown) are adapted to be stretched between a suitable form of tail piece (not shown) which is anchored to the rim adjacent its peripheral edge 11, and a plurality of independent tuning pegs supported in the extremity of the neck 12. The strings are maintained out of contact with the surfaces of the neck and head by a bridge (not shown) which is supported upon and extends normally of the head. A plurality of transverse slots 14 are formed in the upper surface 13 of the neck 12 to receive suitable frets 15.

It is within the contemplation of the present invention to effect angular adjustment of the neck relative to the body and translation of its inner end toward or from the plane of the upper peripheral edge of the body.

To this end, means is provided which affords a bearing surface of substantially constant area between the body and the inner end of the neck for all angular positions of the latter, thereby insuring a rigid relationship between the elements c! the instrument in any desired position of adjustment. In the present embodiment oi' the invention, auch means includes a concave arcuate seat 16 preferably formed in a plate 17 which is Secured to the external peripheral surface of the rim 10 with the plane of its arcuate face submntially normal to the plane of the peripheral edge 11. The plate is retained in position by colmtersunk screws 18 which engage the body of the rim.

The inner end 19 oi' the neck 12 is formed in a convex are whose plane is substantially normal to the piane oi the surface 13 and whose radius is equal to the radius of the arc defining the seat 16. Thus the end 19 of the neck 12 is adapted to be received in abutting contact with the seat 16 and me area of contact is substantially equal throughout the desired range of adjustability of the neck. Translating movement of the end 19 of the neck Illlrelative to the seat 16 is preferably restricted to a plane normal to the peripheral edge 11 of the rim 1li. `To this end, guide means are provided which, in the present instance, comprise alined tongues 20 formed integrally with the plate 17 and adaptedto coact with an elongated groove 21 which projects inwardly from the abutting and "19 of the neck.

l Concealed means is employed to attach the neck to the rim in fixed angular relation, and, in the embodiment of the invention selected for purposes of disclosure, the attaching means is housed within the neck of the instrument and projects inwardly of the rim beneath the head or skin. The inner end of the neck is provided with a bore 22 which extends inwardly from the abutting face 19 eccentrically o1' the longitudinal axis or the neck.

`The attaching means comprises an elongated member 23 having an end 24 anchored in the bore 22, the second end 25 projecting externally of lthe face 19 for engagement with the rim or body. Pivotal movement of the neck relative to the member 23 is provided by the anchored connection of the end 24 of the latter part in the bore 22. A pivot screw 26, is threaded into the neck adjacent the inner end of the bore 22 and projects through an aperture 27 formed near the end 24 of the member 23. The respective ends of the aperture 27 are flared as at 28 to permit angular movement of the member 23 about its end 24 in a plane common to the axis of the pivot screw 26.

The protruding end 25 oi' the member 23 is threaded as at 29 and is adapted to project inwardly of the body of the instrument through alined apertures 30 and 31 formed in the plate 17 and rim 10, respectively. An adjustable nut 32 engages the threaded section 29 and acts against the inner peripheral surface of the rim to clamp the end 19 of the neck 12 in abutting engagement with the seat 16 of the plate 17. A Washer 33 is interposed between the nut 32 and the inner surface of the rim to prevent injury to the latter part.

Thus by manipulating the nut 32 the neck 12 may be adjusted angularly with respect to the plane of the edge 11 by pivotal movement about an axis intermediate its respective ends.

Spacing the pivotal axis of the neck away from the point of contact of its inner end with the seat 16 lessens the extent of angular movement necessary to effect any desired adjustment because the inner end is thereby caused to move toward the strings simultaneously with the action of the remote end of the neck to converge the strings toward its upper surface. Structural characteristics of the neck, however, limit the practical depth of the bore and proportionally restrict the extent to which the pivot point may be removed from its inner or abutting end, as will be seen in Figs. 2 and 3.

Pivotal means have accordingly been provided in which the axis of rotation is further removed from the abutting end of the neck than is the point of connection between the respective elements of the structure.

Referring now to Figs. 2 and 3: It will be seen that the alined apertures 30 and 31 in plate 17 and rim 10 respectively, provide a snug t for the projecting end of member 23, thereby effecting a constant angular relationship between that part and the body. The bore 22, however, is substantlally greater in diameter than is the attach ing member 23 permitting translation of the neck longitudinally of the axis of the pivot screw 26. Were the pivotal connection between the member 23 and the neck incapable of translation axially of the screw 26 then the angular movement of the neck relative to the attaching member would occur about an axis spaced from the abutting end of the neck a distance equal to the distance of the axis of the pivot screw from the end of the neck. The actual axis of rotation, however, is removed a relatively greater distance from the end 19 than is the screw 26 by causing the member 23 to translate with reference to the longitudinal axis of the screw upon what is, in eiect, a cord of the angle whose apex defines the actual axis of rotation of the neck.

Thus, during an adjusting operation, t-he inne; end of the neck is caused to move toward the strings a relatively greater amount than would be possible were the axis of rotation no further from the abutting end 19 than is the pivot screw 26.

The tension of the strings on the instrument i introduces a force acting diametrically of the rim between the abutting end of the neck and the point of attachment of the strings, whose effect is to compress or distort the body of the instrument, thereby destroying the adjustment 1 of the head or skin and simultaneously reducing the tension of the strings and lowering their tonal pitch.

Means is accordingly provided to exert a counteracting force diametrically of the rim from the point of attachment of the neck substantially to the point of attachment of the strings. It is further provided that the counteracting force shall be exerted simultaneously with an operation to clamp the neck in adjusted position. The end 34 of a brace 35 is adjustably secured in any suitable manner to the rim 1() at a point adjacent the point of attachment of the strings. The opposed end 36 of the brace 35 extends in juxtaposition to the inwardly extending portion of the member 23. In the present instance the nut 32 is adapted to engage threads 3'7 on the end 36 of the brace 35 to simultaneously act upon the brace and the member 23. Referring to Figs. l and 4, it will be seen that clockwise rotation of the nut 32 will serve to draw the member 23 inwardly and simultaneously project the end 36 of the brace 35 in the same direction to communicate a stress to the opposed side of the rim which is eiTective to compensate the strain introduced by the strings.

It will be apparent that a comparatively sligh movement of the brace will serve to relieve all compressive strain communicated to `the rim, whereas a relatively greater movement of the member 23 will be required to afford the degree of freedom necessary to readily adjust the neck in a desired angular position. This end has been attained in the present instance by providing the member 23 with threads whose pitch is appreciably greater than is the pitch of the threads 87 upon the brace 35, as will be seen in Fig. 4.

Thus a pivotal connection has been provided for the neck o1 a stringed musical instrument which is concealed from view, which is effective to rotate vthe neck about an axis intermediate its ends, and which is simple and economical of construction. Adjustable brace means has likewise been provided which is effective to communicate stress diametrically of the rim to retain the latter part in proper conformation and to compensate for the stress introduced by the tension of the several strings.

claim as my invention:

1. A stringed musical instrument comprising, in combination, a rim, a plate rigidly secured to the external peripheral surface of said rim, said plate and rim defining radially alined concentric apertures, the outer face of said plate being curved in a concave arc Whose plane is substantially perpendicular to the plane of said rim, a neck having a convex arcuate end adapted to abut the arcuate face of said plate and a longitudinal bore extending inwardly therefrom, an elongated' member universally anchored in said bore and projecting through said concentric apertures inwardly of said rim, a brace rod extending diametrically of said rim substantially in the plane of the longitudinal axis of said neck the end remote from said neck being secured to said rim, the second end extending in juxtaposition to the inner end of said elongated member, and means adapted to communicate a compressive stress to said brace as anincident to exerting a tensile stress on said elongated member.

2. A stringed musical instrument comprising, in combination, a rim having an aperturetherein, a neck adapted to adjustably abut said rim in angular -relation to the plane of the edge thereof, said neck having a bore extending inwardly from said abutting end, means providing a surface contact between said rim and the abutting end of said neck in a plurality of positions of angular adjustment, said means having an aperture concentric with the aperture in said rim, a member universally anchored in said bore and projecting externally thereof, said member being adapted to project inwardly of said rim through said concentric apertures, a brace extending diametrically of said rim substantially in the plane of said neck, the end of said brace remote from said neck being secured to said rim, the second end of said brace extending in juxtaposition to the inner end of said member, and manually rotatable means connecting said member and the juxtaposed end of said brace to clamp said neck in fixed angular relation to said rim, and simultaneously move said brace to communicate force to a point in said rim diametrically opposite the point of attachment of said neck.

3. A stringed musical instrument comprising, in combination, a rim having an aperture therein, a neck having one' end adapted to abut said rim in angular relation to the plane of the edge thereof, said neck having a bore extending inwardly from said abutting end, coacting arcuate seats on said rim and the abutting end of said neck, said arcuate seats having apertures concentric with the aperture in said rim, a member universally anchored in said bore and projecting externally thereof, said member being adapted to project inwardly of said rim through said concentric apertures, a brace extending diametrically of said rim substantially in the plane of said neck, the end of said brace remote from said neck being secured to said rim, the second end of said brace extending in juxtaposition to the inner end of said member, and manually operable means connecting said member and the juxtaposed end of said brace to effect an inward radial movement of said member to clamp said neck in fixed angular relation to said rim, and a relatively lesser movement of said brace to communicate force diametrically of said rim.

` 4. A stringed musical instrument comprising, in combination, a rim having an aperture therein, a neck having one end adapted to adjustably abut said rim in angular relation to the plane of the edge thereof, said neck having a bore extending inwardly from said abutting end, coacting arcuate seats on said rim and the abutting end of said neck, said arcuate seats having an aperture concentric with the aperture in said rim, a member universally anchored in said bore and projecting externally thereof, said member being adapted to project inwardly of said rim through said concentric apertures, a brace extending diametrically of said rim substantially in the plane of said neck, the end of said brace remote from said neck being secured to said rim, the second end of said brace extending in juxtaposition to the inner end of said member, and manually operable means connecting said member and the 1 juxtaposed end of said brace simultaneously to effect an inward radial movement of said ber to clamp said neck in xed angular relation to said rim, and a relatively lesser movement of said brace to communicate force diametrically il@ of said rim.

5. A stringed musical instrument comprising, in combination, a rim having an aperture therein, a neck adapted to adjustably abut said rim in angular relation to the plane of the edge thereof, said neck having a bore extending inwardly from said abutting end, means providing a surface contact betwen said rim and the abutting end of said neck, said means having an aperture concentric with the aperture in said rim, a. member universally anchored in said bore and projecting externally thereof, said member being adapted to project inwardly of said rim through said concentric apertures, a brace extending diametrically of said rim substantially in the plane of said neck, the end of said brace remote from said neck being secured to said rim, the second end of said brace extending in juxtaposition to the inner end of said member, and manually operable means connecting said member and the juxtaposed end of said brace simultaneously to eiect a clamping of said neck in fixed angular relation to said rim, and to communicate force diametrically of said rim.

6. A stringed musical instrument comprising, incombination, a rim having an aperture therein, a neck adapted to adjustably abut said rim in angular relation to the plane of the edge thereof, said neck having a bore extending inwardly from said abutting end, means providing a surface contact between said rim and the abutting end of said neck, said means having an aperture concentric With the aperture in said rim, a member universally anchored in said bere and projecting externally thereof, said member being adapted to project inwardly of said rim through said alined apertures, a brace extending diametrically o! said rim substantially in the plane of said neck, the end of said brace remote from said neck being secured to said rim, the second end of said brace extending in juxtaposition to the inner end of said member, and means embracing said member and the juxtaposed end of said brace to effect an inward radial movement of said member to clamp said neck in xed angular relation to said rim, and a corresponding movement of said brace to communicate force diametrically of said rim.

7. A stringed musical instrument comprising, in combination, a rim, a plate rigidly secured to the external peripheral surface thereof, said rim and plate having alined concentric apertures, the outer face of said plate being curved in a plane substantially perpendicular to the plane of said rim, a neck having a curved end adapted to abut the curved face of said plate and an elongated longitudinal bore extending inwardly therefrom, a member pivoted in said bore and projecting in- Wardly ol said rim through said concentric apertures, a brace extending diametrically of said rim substantially in the plane of said neck and having one end secured to the periphery thereof, and means adapted to engage the inwardly projecting end of said member and the second end of said brace to secure said neck in fixed angular relation to the plane of said rim and to communicate a compressive stress to said brace.

8. A stringed musical instrument comprising, in combination, a rim having an aperture therein, a neck having one end adapted adjustably to abut said rim in angular relation to the plane of the peripheral edge thereof, said neck having a bore extending inwardly from said abutting end, means eiective to provide a surface contact between said rim and the abutting end of said neck, said means having an aperture concentric with the aperture in said rim, a member pivoted in said bore and projecting inwardly of said rim thnough said concentric apertures. a brace extending diametrically of said rim substantially in plane of said neck and having one end scoured to the periphery thereof, and means adapted to engage the inwardly projecting end of said member and the second end oi said brace to secure said neck in fixed angular relation to the plane of said rim and to communicate a compressive stress to said brace.

9. A stringed musical instrument having, in combination, a rim having an aperture therein, a neck having one end adapted adjustably to abut said rim in angular relation to the plane of the edge thereof, said neck having a bore extending inwardly from said abutting end, means providing a surface contact between said rim and the abutting end of said neck, said means having an aperture concentric with the aperture in said rim, a member having a pivotal and translating connection with said neck inwardly of said bore, said member projecting through said concentric apertures inwardly of said rim, a brace extending diametrically of said rim and having one end anchored thereto at a point substantially opposite the point of attachment of said neck, and a single adjustable means effective to connect the second end of said brace to said rim and to clamp the abutting end of said neck in fixed angular relation to the plane of the peripheral edge of said rim. Y

10, In a stringed musical instrument, in combination with the body and neck, an adjustable mounting for the neck comprising coacting arcuate seats on the body and neck permitting angular adjustment relative to said body, and a clamp for connecting said neck to said body, said clamp being pivotally and translatably connected to said neck intermediate its respective ends.

11. In a stringed musical instrument, in combination with the body and neck, an adjustable mounting for the neck comprising coasting arcuate seats on the body and neck to provide a bearing surface of substantially constant area with the neck in angular adjustment relative to the body, and a clamp concealed within said neck for connecting said neck to said body, said clamp being pivotally connected to said neck intermediate its respective ends.

12. A neck for a stringed musical instrument of the type including a neck and body portion, said neck comprising an elongated member having an end adapted to abut the body portion and a bore opening inwardly from said end, and means mounted within said bore and projecting substantially longitudinally therefrom for engagement with said body, said neck being pivotally movable relative to said means about a point intermediate its respective ends, and bodily movable relative to said means in a plane substantially normal to its longitudinal axes.

13. A neck for a stringed musical instrument of the type including a neck and body portion, said neck comprising an elongated member having an end adapted to transatably abut the bodyportion and a bore opening inwardly from said end and connecting means universally mounted within said bore and projecting outwardly therefrom for engagement with said body, said neck being movable relative to said means about an axis removed from said abutting end a relatively greater distance than is the closed end of said bore.

14. A neck for a stringed musical instrument of the type including a neck and body portion, said neck comprising an elongated member havber having an end adapted to translatably and pivotally abut the body portion and a bore opening `inwardly from said end and means within l said bore and projecting outwardly therefrom for engagement with said body, said neck being movable pivotally relative to said means about an axis normal to its longitudinal axis and translatable in a plane normal to the plane of the instrument.

15. A stringed musical instrument comprising, in combination, a rim having an aperture therein, a neck having one end adapted to adjustably abut said rim in angular relation to the plane of the edge thereof, means providing a surface contact between said rim and the abutting end oi' said neck, said means having an aperture concentric with the aperture in said rim, a universal connecting member anchored to said neck adjacent its abutting end and projecting into the interior of said rim through said concentric apertures, and means on said member adapted to act against the inner peripheral wall of said rim adjustably to position the abutting end of said neck in fixed bodily relation with said rim.

16. A stringed musical instrument comprising, in combination, a rim having an aperture therein, a neck having one end adapted adjustably to abut said rim in angular relation to the plane of the edge thereof, said neck having a bore extending inwardly from said abutting end, means providing a surface contact between said rim and the abutting end oi said neck, said means having an aperture concentric with the aperture in said rim, a threaded member, one end of which is ivotally anchored adjacent the inner end of said bore, the second end of which projects through said concentric apertures into the interior oi said rim, and an adjustable nut on the inner end of said threaded member adapted to act against the inner peripheral wall of said rim to clamp said neck in fixed angular relation with said rim.

17. A neck for a stringed musical instrument comprising an elongated member having one end adapted to abut the instrument, the other end extending outwardly therefrom, a member having a pivotal and translatory connection with said neck adjacent said abutting end, said member projecting from said neck for engagement with the instrument, saidneck being movable relative to said member about an axis removed from abutting end a relatively greater distance than is said connection.

18. In combination with a stringed musical instrument having a rim and a head supported on said rim, a neck comprising an elongated member having a convex arcuate end adapted to abut said rim and an elongated cylindrical bore eccentric of its longitudinal axis'and opening inwardly from said arcuate end, means mounted within said bore to connect said neck with said rim, and means to effect pivotal adjustment of said neck about an axis perpendicular to the longitudinal axis of said bore and translating movement of said neck relative to said head.

'19. In combination with a stringed musical instrument having a rim and a head supported on said rim, a neck in movable abutment With said rim, connecting means to rigidly secure said neck in angular relation to said head and adjusting means adapted to permit translation of said neck toward and from the plane of said head.

20. In combination with a stringed musical instrument having a rim and a head supported on said rim, a neck in movable abutment with said rim, connecting means to maintain said neck in iixed position relative to said rim and adjusting means adapted to permit bodily movement of said neck normally of the plane of said head.

21. In combination with a stringed musical instrument of the class ldescribed having a body and a head supported thereby, a neck adapted to abut said body and means to connect said neck to said body, said connecting means being adapted to permit pivotal movement of said neck about an axis intermediate the ends thereof and translating movement of said neck relative to the head of said instrument.

22. In combination with a stringed musical instrument of the class described having a body comprising an annular rim, a head supported on said rim, and a neck adapted to abut said rim, connecting means adapted to permit angular movement of said neck in planes normal to, and parallel with, the plane of said head, bracing means to reinforce said rim and manipulative means operable to simultaneously adjust said connecting means and said brace.

23. A stringed musical instrument comprising, in combination, a rim, a neck having one end in abutment with said rim in adjustable angular lrelation to the plane of the peripheral edge thereof, means providing a surface contact between said rim and the abutting end of said neck in a plurality of angular positions of the latter, an adjustable brace extending diametrically of said rim, and a single manipulative adjusting means operable to stress said brace and to secure said neck in fixed angular adjustment.

24. A stringed musical instrument comprising, in combination, a rim, a head supported thereby,

a neck having one end in adjustable abutment with said rim, an adjustable brace extending diametrically of said rim, means to effect bodily movement of the abutting end of said neck relative to the plane of said head and manipulative adjusting means operable to stress said brace and to secure said neck in fixed bodily position relative to said head.

25.' A stringed musical instrument comprising,

in combination, a' rim, a head supported thereby,

a neck having one end in abutment with said rim,

means to effect bodily movement of said neck relative to the plane of said head and pivotal movement or". said neck about an axis parallel to the plane of said head, an adjustable brace extending diametrically of said rim, and a single

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