US2549914A

US2549914A - Stringed musical instrument

Info

Publication number: US2549914A
Application number: US701564A
Authority: US
Inventors: John W Mcbride
Original assignee: BANTAR Inc
Current assignee: BANTAR Inc
Priority date: 1946-10-05
Filing date: 1946-10-05
Publication date: 1951-04-24
Anticipated expiration: 1968-04-24

Description

April 24, 1951 J w MOBRIDE STRINGED MUSICAL INSTRUMENT 6 Sheets-Sheet 1 Filed Oct. 5, 1946 Q-NN hh INVENTOR John W McBr/c/e fl Z/W,

v- ATTOFFNEY l 24, 1951 J. w. MCBRIDE 2,549,914

STRINGED MUSICAL INSTRUMENT Filed Oct. 5, 1946 6 Sheets-Sheet 2 INVENTOR a 6 Jo/m W McBr/oe ATTORNEY April 24, 1951 JQ W. M BRIDE 2,549,914

STRINGED MUSICAL INSTRUMENT Filed Oct. 5, 1-346 6 Sheets-Sheet 5 ATTORNEY April 24, 1951 J. w. M BRIDE STRINGED MUSICAL INSTRUMENT 6 Sheets-Sheet 4 Filed Oct. 5, 1946 INVENTOR Ja/m W Mcfi/fde /6% V 444 ATTORNEY April 1951 I J. w. MCBRIDE 2,549,914

STRINGED MUSICAL INSTRUMENT Filed oct. 5, 1946 e Sheets-Sheet 5 A52 /40 I33 I40 /42 /4/ Z f H f ATTORNEY April 24, 1951 J. w. MCBRIDE Q 2,549,914

STRINGED MUSICAL INSTRUMENT Filed Oct. 5, 194a e Sheets-Sheet 6 INVENTO John W Mcfirk'de AT TORNEY Patented Apr. 24, 1951 UNITED STATES PATENT OFFICE STRINGED MUSICAL INSTRUMENT John W. McBride, Burbank, Galifl, assignor to Bantar, Incorporated, Burbank, Califl, a corporation of California Application October 5, 1946, Serial No. 701,564

18 Claims. 1

This invention relates to. a stringed musical instrument.

In such instruments the pitch of the musical note produced by any of the strings is determined by the free vibrating length of the string. The conventional manner of determining such length and hence the pitch of the note is by stopping the string with the finger. However, it has been proposed to provide mechanical means for this purpose, controlled by a key mechanism operated by the fingers of the player.

For example, in Patent No. 2,405,316, issued to John W. McBride on August 6, 1946, a tuning mechanism is disclosed utilizing a movably supported member having a string contacting crest. The crest lies substantially in a plane parallel with the direction of movement of the member which movement is constrained to be parallel with the string. The crest itself is transverse to the string. A key is provided for operating the member, movement of the member causing the point of contact between the string and the crest to move progressively along the string and thus to alter its free vibrating length.

It is an object of this invention to provide an improved form of such mechanism.

It is another object of this invention to provide mechanism of this type giving" improved support to the tuning members.

It is another object of this invention to provide such mechanism having an improved arrangement of the operation keys for the tuning members.

In the above mentioned patent, the tuning members are mounted at one end for pivotal movement past the cooperating string, in a direction generally transverse of the string, the movement of the crest along the string being due to the oblique positions of the crest with respect to the string.

It is still another object of this invention to provide a tuning mechanism in which the entire tuning member is movable past the string. In thisway, the mechanism may be simplified.

It is still another object of this invention to provide a tuning mechanism in which the tuning member moves generally lengthwise of the string.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several embodiments of the invention. For this purpose there are shown a. few forms in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating. the gen ral prin- 2 ciples of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

In the drawings:

Figure 1 is a plan view of an instrument incorporating features of the invention;

Fig. 2 is a transverse sectional View on an enlarged scale, taken as indicated by the lines 2--2 of Fig. 1, parts of the instrument being broken away to reduce the size of the figure Fig. 3 is a cross sectional view on a further enlarged scale, taken as indicated by lines 3-3 of Fig. 1;

Fig. 4 is a fragmentary plan view with the tuningmechanism removed, taken substantially as indicated by lines 4-4 of Fig. 2, and on an enlarged scale;v

Figs. 5 and 6 are detail views of one of the string supporting elements;

Fig. 7 is a view similar to Fig. 1 but showing a modified form of the invention;

Fig. 8 is a cross sectional view on an enlarged scale, taken as indicated by.- lines 88 of Fig. 7;

Fig. 9 is a plan view of a modified form of tuning element which may be employed with the instrument of Fig. 7;

Fig. 10 is a cross section on an enlarged scale, taken as indicated by lines III-10 in Fig. 9;

Fig. 11 is a view similar to Fig. 1, but showing another modified form of the invention;

Fig. 12 is a cross sectional view on an enlarged scale, taken as indicated by lines l2! 2 of Fig. 11;

Fig. 13 and 14 are detail sections, taken as indicated by correspondingly numbered lines on Fig. 11;

Fig. 15 is a plan view showing still another modified form of the invention;

Fig. 16 is a cross sectional view, partly in elevation and on an enlarged scale, takenas indicated by lines I6I6 on Fig. 15;

Figs. 17 and 18 are detail sections, taken as indicated by correspondingly numbered lines on Fig. 16;

Fig. 19 is a detail section taken as indicated by line l9 IS on Fig. 15; and

Fig. 20 is a plan view of another modified form of the invention.

Referring to Figs. 1-6 of the drawings, an instrument is shown wherein the strings are adapted to be set into vibration by plucking, as in a guitar or banjo. The instrument comprises a body i, formed of wood or other suitable material, which serves to mount. the operating parts of the instrument, suitable cavities and recesses being provided where required for their accommodation.

A pair of

string structures

2 and 3 extend in substantial parallelism over the top of the body I. As shown, each of these

structures

2 and 3 comprises a set of two strings 2a and 2b, and 3a and 3-b respectively, the strings in each set being quite closely spaced. However, it is to be understood that either or both of these string structures may comprise any other desired number of strings, or a single string.

Each string 2a, 2-b, 3-a and 3-b, passes over a supporting post 4 adjacent the right hand end of the body I, and thence downwardly through an aperture 5 in the body, in which the string is anchored in a conventional manner (see Fig. 2). At the opposite end of the body the string passes over a similar post 6 and thence to a conventional tuning peg 'I-'. By appropriate adjustment of the tuning peg I, the string may be tensioned as required between the posts A and 6.

The

posts

4 and 5 are adjustable for height. For this purpose they comprise headless machine screws threaded into plates 8 and 9 secured respectively to the body I adjacent the opposite ends thereof, each plate accommodating a pair of posts. Lock nuts (not shown) may be provided, if desired, for securing the post 4 or 6 in adjusted position.

The posts 4 and 6 are substantially identical, one of the posts being shown in detail in Figs. 5 and 6. The upper end 4-a of the post is of inverted V-form, and has a kerf 4b with a convex bottom surface, for supporting the string and positioning it laterally. The strings 2a, 2b, 3a and 3-b are not necessarily all at the same height as shown, since under some conditions it may be desirable to have one or more of the strings higher than the others.

Provisions are made for stopping each of the strings 2a, 2b, 3a and 3b at one or more points intermediate the supports 4 and 6. These provisions include pairs of tuning members generally indicated by the numerals I3 and I4 and cooperating respectively with the

string structures

2 and 3. Since each pair of members I3 and I4 and its manner of tuning the associated string structure are substantially identical, only one of such pairs, as the pair indicated by the numeral I3, will be described.

This pair I3, as clearly shown in Figs. 1, 2 and 3, comprises the fiat elongated members I5 and I6 supported for transverse movement with respect to the string structure 2, and located between the body I and the string structure. The members I5 and I6 have oppositely bevelled upper edge surfaces providing string contacting crests l1 and I8 respectively. Furthermore, the members I5 and I6 are inclined in the direction of their movement so that the crests I1 and I8 cross the string structure 2 at an angle. Accordingly, the crests ii and I8 contact the string structure 2 at points located along the string structure in accordance with the transverse positions of the members with respect to the string structure. Thus by moving the members to alter such positions, the crests are caused to move progressively along the string structure and. vary the free vibrating lengths thereof.

The pair I4 comprises the members I9 and which are shown as substantially identical respectively with the members I5 and I6, and are similarly supported for transverse movement between the body I and the string structure ,3.

The mechanism for supporting and operating the members I5, I6, I9 and 20 is shown as including a frame 2I formed of sheet metal and suitably secured on the body I. This frame 2i comprises a rectangular plate 22 with raised portions or rails 22-a and 22b at its opposite ends, extending crosswise of the body I, for slidably supporting the members I5, I6, I9 and 2|. The plate 22 has an extension 23 at one end for a purpose to be pointed out shortly. Due to the proportioning of the parts, crests [1, I8, etc. are contacted with a slight pressure by the strings.

The longitudinal edges of the plate 22 are provided with upstanding projections or

legs

24 and 25. These legs have pairs of aligned apertures, such as 26 and 2'! in Fig. 3, for slidably accommodating respectively rods 33, 3I, 32, 33. All of these rods extend through the tuning members I5, I6, I9 and 20, each rod being secured to one of the respective members, and being freely slidable through the other members. Thus, as clearly shown in Fig. 3, the rod 3| is fixed to the member I5 and passes through clearance apertures I6a, I 9a and Zil-a in the members I6, I9 and 20. Similarly, rod 30 is secured to bar I6, rod 32 is secured to bar I9, and rod 33 is secured to bar 20, the rods passing through clearance apertures in the bars to which they are not attached. In this way the rods 30, 3|, etc., serve to position the members I5, I 8, etc.

The rods 30, 3i, 32 and 33 have operating or

finger keys

34, 35, 36 and 37 respectively secured on the corresponding ends thereof. Each key serves to confine a compression spring, as 38 (Fig. 3) against the frame leg 24. The springs urge the respective rods, as 3|, together with the attached member or bar I5 to the left referring to Fig. 3, or upwardly referring to Fig. 1. This upward movement is limited by a collar 39 (Fig. 3) secured to the end of the rod opposite the key 35 and engaging the frame leg 25. These collars 39 serve to limit movement of the

respective bars

36, 3|, etc., in response to springs 38, so that the tuning members are normally in their initial or home positions.

Thus appropriate pressure on the keys 3d, 35, etc. serves to move the attached tuning members, or bars I5, I6, etc., from their initial positions against the force of the springs 38 so that the associated string structures will be stopped at the desired points. Release of such pressure will allow the members I5, I5, etc. to be returned by the springs 38 to their initial positions.

Although the bars I5 and I6 of the pair I3 have

independent keys

34 and 35, relative movement between the bars I5 and I6 is limited since the bars are quite closely spaced. A cushioning washer 40 of felt or rubber is provided between the members I5 and I6 on one or more of the rods, such as shown on rod 3|. Thus in Fig. 1, downward movement of the member I5 by pressure on key 35 will cause corresponding movement of the member I8, the members I5 and It thus moving as a unit. Release of pressure on the key 35 will allow the members I5 and I6 to return upwardly, also as a unit. However optionally pressure may be exerted on the key 34 to prevent such return movement of the member It, or to cause it to move downwardly independently of the member I5.

The bars I9 and 20 of the other pair I4 similarly have limited independent movement. Thus the key 36 serves to control the position s. of the member [9; which. by means of. the cushionary washer. 4i limits the upward movement of the other member 20-. However, this member 20 may be moved downwardly independently of member l9 bymeans of the key 3.1. These bars [9 and 29 are movable entirely independently of the bars l5. and it of the other pair IS.

The tuning member It, by virtue of its crest I1 contacting the strings 2a. and 2 -b, will divide the strings between their supporting posts 4' and 6 into two portions having relative. lengths in accordance with the position of member transversely of the string structure. 2. Further, the other tuning member [6 will divide one of these portions into two shorter portions having relative lengths determined by the transverse position of the member it.

Any or all of these string portions may be set into vibration by the player, either separately or in unison. For utilizing the sound vibrations from these string portions, conventional electric pick-ups 5b and. 5| are mounted on the body I respectively adjacent the string supports 4 and 6' so as to be afiected when any of the string portions are caused to vibrate.

Asis well understood, such. pick-ups usually comprise means forming a magnetic circuit and a winding, the magnetic circuit being so arrangedv that when influenced by the vibrating strings, electrical, impulses are created in the Winding corresponding with the vibrations of the strings. The windings of the pick-ups 5i) and 5! are connected by appropriate wiring (not shown) accommodated in a passage 52 formed in the body I, with a phone jack to facilitate connection to a conventional loud speaker system.

A rheostat 53 (Figs. 2 and 4) for controlling the output from the pick-ups 5'9 and. 51 is mounted in a cavity 54 formed in the body I', and covered by part of the plate 22 and the extension 23 thereof. An operating lever 55 for the rheostat 53 is mounted for angular movement in the cavity 54., as by being secured to the upper end of. a shaft 56 rotatably carried by a. bushing 51 fixed in the body I. A pivoted link 58 connects the lever 55 with the rheostat arm 59.. The lever 55 has an upward extension 55-a. (Fig. 2) with a thumb rest 66 formed thereon adjacent the key 34.

The instrument may be played optionally in either of two positions. Thus it may rest on the players lap or on a suitable table or stand with the key mechanism and strings generally horizontal. The player then reaches across the strings with his left hand, manipulating the keys S4, 35, 36 and 31 with his fingers, and operating the volume control lever 55 with his thumb. The right hand is utilized to pluck the strings or otherwise to set them vibrating. However, if desired, the player may extend his left hand between the instrument, so as to support the instrument, and direct his fingers upwardly to operate the keys 34, etc.

For operating the volume control with the instrument played in this manner, a supplemental operating lever 5| accommodated for angular movement in a recess 62 formed on the lower side of the body I, secured on the lower end of shaft 56. A cover plate 63 is provided for the recess 52 cooperating therewith to form an arcuate opening or slot 64 (Fig. 2.) for accommodating a thumb rest Bl-a formed on the lever BI, which is engageable by the players thumb- In Figs. 7 and 8,. a form of. the invention is shown which is quit similar to the instrument just described. Four string structures 1!, T2, T3 and is, appropriately tensionecl between conventional bridges 15 and T6, are provided, and are tuned respectively by independently operable tuning members ll, E8, '19 and 86'. Each of these members comprises an elongated bar supported for transverse movement between the respective string structure and the instrument body 8! by a frame 82, and having a string contacting crest crossing the string structureobliquely.

The members l7, 18, 1-9 and are secured respectively to the

rods

83, 84, 8'5 and E26 slidable in the frame 82 and passing through clearance apertures in the members to which the rods are not secured. Springs, as 83, urge each tuning member to its initial position, keys SH, 92, 93

and 95 being provided for operating respectively the tuning members to vary the free vibrating lengths of the strings.

In Figs. 9 and 10, a tuning member is shown having a plurality of string contacting crests 95 and 91.. Such a bar may be substituted for. one or more of the members II, 78, I9 and 80 in the instrument of Fig. '7.

In the instruments of Figs. 1 and 7, the string contacting crests are straight in the direction of movement of the tuning member, and cross the string obliquely and at an angle which is constant for all positions of the tuning member, since the member moves along. a right line. Thus the crest moves progressively along the string at a constant rate with respect to transverse movement of the tuning member. t may be desirable to have such progressive movement along the strin occur at a rate which varies for different positions of the tuning member. Such change in rate can be provided by curving the crest.

In Figs. 11-14 an instrument is shown utilizing tuning members having curved crests, and which are movable transversely of the strings.

This instrument is quite similar to the instrument of Fig. 1. It includes a body IE1! with string structures I02 and N3 supported thereon, each comprising. a pair of tensionecl strings. Pairs of. tuning members 164 and are provided for altering the free vibrating lengths. respectively of the string structures I52. and m3. Since the pairs of members and their cooperation with. the associated string structur are substantially identical, only the members of one pair, for example, the pair Hi5, will be discussed.

This pair Hi5 comprises the tuning members I56 and it! having string contacting crests [BE-a and Mil-a respectively so curved.- in the direction of movement of the member as to cross the strings Il13-a and Hi3-b of the string structure; 193 at an angle, each crest contacting each string at but one point. The members I06 and till are supported for limited independent movement with respect to the strings lll3w and [83-h by a pivot structure Hi8 (Fig. 13).

Referring to Fig. 13,. the pivot structure H18 comprises a bearing N39 with a mounting flange ilil therein, secured in a recess ii! provided in the body NH. A shaft H2 rotatable in the bearing. Hi9 extends upwardly thereupon and has the hub ib'i-b of member it! secured thereon a suitable distance above the bearing Hi9 to accommodate hub HIS-b of. the tuning member I95 therebetween. The hub !El5b is freely movable both angularly and axially 0n the shaft H2 and is supported on the. upper end of the bearing I09.

The hub I'Ib in turn is axially supported on the upper end of the hub I06b. The member I06 is ofiset as at I06-c to permit this arrangement while positioning the crest I00a at the same distance above the body IOI as crest I07a.

Additional support is provided for the tuning members E and I01, as well as for the members of the other pair I04 by a member H3 extending across the body IOI providing a rail, which slidably supports the ends of the tuning members remote from the pivots. Additionally, this rail structure serves to determine the initial position of the tuning members I06 and I01 by means of a projection II3-a engageable by the member I06 and a projection I I3b similarly cooperating with the members of pair I04.

A pair of torsion springs H4 and H5 are accommodated on the hub I0Ib for urging the members I65 and IE7 respectively to their initial positions. For this purpose, the spring H5 has an extension II ia from one end engaging a stop H5 on the body NH and an extension H4 17 from the other end engaging the member I03. These extensions and the spring II4 are so arranged that movement of the member I33 from its initial position (downwardly about pivot I38 in Fig. 11) is resiliently opposed by the spring. Similarly, the spring I I5 has an extension I I5-a engaging the stop H6 and an extension H5-b engaging the member I01.

As above indicated, the tuning members H8 and III) of the pair I04 are arranged substantially the same respectively as members I06 and I 0?, being pivotally supported by a structure 5 similar to the pivot structure I08 and urged resiliently toward the projection I I3b.

A series of keys I2I, I2, I23 and IE4 are provided intermediate the ends of the tuning members I05, I57, H8 and H9 respectively for operating the members to tune the string structures.

These keys extend downwardly in a through opening 25 in the central portion of the body IEI, so as to be readily accessible to the fingers of the players left hand, which hand is used to support the instrument, while the right hand plucks or otherwise sets the strings vibrating.

These keys IZI, I22, I23 and I24 have lateral portions I2Ia, I22a, I23a and I24a, joining the keys to the tuning members I06, I01, H3 and H9 respectively.

In the forms of the invention so far described, the tuning members are arranged to move in a direction generally transverse of the strings, the string contacting crest being so inclined as to be moved along the string by such movement of the tuning member.

In Figs. 1-5 to 19, an instrument is shown in which the tuning members are arranged to move generally lengthwise of the strings.

Referring to Fig. 15, the instrurnent is shown as comprisin a body I3I having a pair of tensioned string structures I32 and I33 thereon cooperating with the electric pick-ups I34 and I35. The body I3I has an extension I3I--a on which the pairs of tuning members I36 and I3! are mounted for angular movement about a common axis I38. This axis is located at a point intermediate the ends of the string structures I32 and I33 and spaced a substantial distance laterally therefrom, so that those portions of the tuning members adjacent the string move generally lengthwise of the string structures upon movement of the tuning members through a considerable angle about the axis I38.

As best shown in Figs. and 18, tuning members I40 and MI having string contacting crests I40a and I4Ia, comprise the pair I36. These crests are straight throughout most of the lengths, but may be curved if desired to maintain the angle at which the crest crosses the string more nearly constant for all positions of the members. The outer end portions of the members I40 and I4! are positioned between the body I3I and the string structures I32 and I33, and are offset as at I45b and I4Ib to clear the members I42 and I43 of the other pair I31. (See Fig. 16.)

The member I 10 is further offset to provide a portion I44 to which is secured one leaf I45 of a hinge-like structure which pivotally supports the member I 50 for movement about the axis I38. This leaf I45 extends a suitable distance along the offset I 34 to provide a key surface I43 adapted to be engaged by the players finger for operating the member 18. The other leaf I41 of the hinge is common to all the tuning members, I40, I, E42 and I43 and is suitably secured to the body extension I3I-a so as to support a hinge pin I48. The axis of pin I48 coincides with the axis I38.

The leaf S45 terminates in a hublike portion IE9 which encircles the pin I48 and axially supports the leaf I45 and member I40 by engaging the hub 550 on the fixed leaf I 47. The hub I49 has a slot hie-a intermediate its ends for accominc-dating a torsion spring I5! encircling the pin I 58. The spring l5! has an extension I5Ia engaging the leaf I45 and an oppositely directed extension I5ib engaging the leaf I 41 (see Fig. 17). The spring I5I is so formed and arranged that the member M0 is urged counterclockwise about the axis I38 to engage a stop I52, which determines the initial or home position of the member I40.

The other member I4I also has an offset portion i54 carrying a hinge leaf I55 having a key surface I55 as well as a hub I57 arranged to encircle the pin I45 so as to be pivoted therein and being axially supported on the hub I49. The offset I 54 is also slightly inclined so that the portion of member MI which is about the surface of the body I3I extends parallel with the member I30. A torsion spring I58 similar to the spring I5I urges the member I4I counterclockwise until stopped by contacting the member I 40. If membe N50 is in home position against stop tI52, member Mi will then also be in home posiion.

Appropriate pressure exerted on the key surface I45 will swing both members I40 and MI against the force exerted by the springs I5I and I58 about the axis I38 until stopped by the engagement of the member I4I with stop I59. (Fig. 15.) The member I-ti can be moved independently against the force of spring I58 to en a stop I59 by pressure on the key surface I56. Release of the pressure on the key surfaces I46 and I56 will allow the members M8 and MI to be returned counterclockwise by the springs I5I and IE8. However it will be clear that independent movement Or" the members I40 and MI is limited, since member I40 can be moved clockwise independently only until it contacts the member I42, and conversely the member MI can be moved independently counterclockwise only until it contacts the member I 30.

The other pair of members I42 and I43 similarly have ofisets I60 and I6I to which are attached respectively the hinge leafs I02 and I63 forming ke surfaces I64 and I65 and supporting the members if! and I43 on the hinge pin I48. Torsion springs I66 and IE1 urge the members I42 and I43 to home position against stop I68, the members being capable of limited independent movement, as before.

It will be apparent that appropriate pressure on the various key surfaces I46, I56, I64 and I65 Will cause the associated tuning members I, I4I, I42 and I43 to adjust the free vibrating lengths of the string structures. Further, the pair of crests, as IMF-a and I II 'a, provided for each string structure will divide the string structures into end portions and an intermediate piertion, all independently adjustable within limits.

The pick-ups I34 and I35 are connected by suitable Wiring, (not shown) accommodated in passages as Itt formed in the body I3I, with a conventional phone jack. A rheostat I61 (see Figs. and 19) is provided in the body extension I3 I--a to control the sound volume, and is arranged to be operated by an arm I88 secured on the rheostat shaft I6'I-a. A torsion spring I69 serves to urge the arm I68 to one of its limitin positions, appropriate pressure on the thumb rest Ifi8-a provided on the free end of arm I68 serving to operate the rheostat I61. As clearly shown in Figs. 15 and 16, the thumb rest I58.--a is so located as to be comfortably reached by the players thumb when the fingers are in position to engage the key surfaces I46, I56, I64 and I65.

Other arrangements may be utilized to provide movement of the tuning 7 members along the strings. For example, in Fig. a fragment of an instrument is shown which employs tuning members having straight string contacting crests and which is otherwise quite similar to the form of Fig. '7. However, in this form the frame I'I5 is set so that the operating rods I76 for the respective tuning members I'll move at an angle with respect to the strings Il8. Accordingly movement of the tuning members will have a component parallel with the strings, depending on the size of this angle.

The inventor claims:

1. In a stringed musical instrument: a body; a plurality of parallel tensioned strings spaced from the body; a plurality of bars having crests for contacting respectively said strings; and means for independently translating said bars to different positions between said body and said strings to move said crests progressively along the respective strings and vary the free vibrating length thereof.

2. In a stringed musical instrument: a body; a plurality of tensioned strings spaced from the body; a plurality of bars having crests for contacting respectively said strings; and means for independently translating said bars to different positions in substantially a common plane between said body and said string so that the apexes of the crests move progressively along the respective strings and vary the free vibrating length thereof.

3. In a stringed musical instrument: a tensioned string; a bar having a string contacting crest; means mounting said bar for movement to cause the crest to move progressively along the string and vary the free vibrating length thereof; and means attached to said bar forming an operating key therefor intermediate the ends of the bar.

4. In a stringed musical instrument: a body; a

tensioned string spaced from the body; a bar hav-v ing a string contacting crest; means mounting said bar for movement between said body and said string to cause the crest to move progressively along the string and vary the free vibrating length thereof; and means attached to said bar forming an operating key therefor intermediate the ends of the bar.

5. In a stringed musical instrument: a tensioned string; a bar having a string contacting crest; means mounting said bar for movement between limiting positions to cause the crest to move progressively along the string and vary the free vibrating length thereof; means resiliently urging said bar toward one of said limiting positions; and means attached to said bar forming an operating key therefor intermediate the ends of the bar.

6. In a stringed musical instrument: a body; a plurality of tensioned strings spaced from the body; a bar for each of said strings having a string contacting crest; means mounting said bars for independent movement between said body and said string to cause the crests to move progressively along the respective strings and vary the free vibrating length thereof; stop means for limiting movement of said bars in one direction; means resiliently urging said bars toward said stop means; and means attached to each bar forming an operating key therefor.

7. In a stringed musical instrument: a body; a tensioned string structure spaced from the body; a plurality of members providing crests for contacting said string structure at points spaced therealong to form a plurality of free vibrating string lengths; and means for independently translating said members between said body and the string structure to move the crests progressively along the string structure and vary said free vibrating string lengths.

8. In a stringed musical instrument: a body; a tensioned string structure spaced from the body; means providing one or more string contacting crests; and means supporting said crest providing means adjacent its end portions on the body for movement between the body and said string structure to cause said crest or crests to move rogres sively along the string structure and vary the free vibrating lengths thereof, one of said supportin means comprising a member extending transversely of the string structure on the body and movably engaging said crest providing means.

9. In a stringed musical instrument: a body; a tensioned string structure spaced from the body; means providing one or more string contacting crests; and means supporting said crest providing means on the body for movement between the body and said string structure to cause said crest or crests to move progressively along the string structure and vary the free vibrating lengths thereof, said supporting means comprising a pair of rails extending transversely of the string structure on the bod and slidably engaging the opposite end portions of the crest providing means.

10. In a stringed musical instrument: a body; a tensioned string structure spaced from the body; means providing one or more string contacting crests; means pivotally mounting said crest providing means on the body for movement between the body and said string structure to cause said crest or crests to move progressively along the string structure and vary the free vibrating lengths thereof; and a plurality of electrio pick-up means respectively at points spaced along the string structure to amplify independentl the vibrations of different free vibrating lengths of said string structure.

11. In a stringed musical instrument: a body; a tensioned string structure spaced from the body; a bar having one or more string contacting crests; means mounting said bar for translating movement between the body and the string structure transversely past the string structure, said crest or crests being inclined with respect to said structure and the direction of movement, whereby movement of the bar moves said crest or crests progressively along the string structure and varies the free vibrating lengths thereof; and means for moving said bar. v

12. In a stringed musical instrument: a body; a tensioned string structure spaced from the body; a bar having one or more string contacting crests; means mounting said bar for translating movement between the body and the string struce ture transversely past the string structure, said crest or crests being inclined with respect to said structure and the direction of movement, whereby movement of the bar moves said crest or crests progressively along the string structure and varies the free vibrating lengths thereof; means resiliently urging said bar to an initial position; and means for moving said bar with respect to said position.

13. In a stringed musical instrument: a body; a tensioned string structure spaced from the body; a bar having one or more string contacting crests; means pivotally mounting said bar adjacent the string structure for swinging movement between the body and the string structure in a direction generally transverse of the string structure, said movement causing said crest or crests to move progressively along the string structure and vary the free vibrating lengths thereof; and a plurality of electric pick-up means respectively at points spaced along the string structure to amplify independently the vibrations of difierent free vibrating lengths of said string structure.

14. In a stringed musical instrument: a tensioned string structure; a bar, at least a portion thereof having one or more string contacting crests; and means for moving said bar to move said portion bodily generally lengthwise of the string structure, whereby said crest or crests move progressively along the string structure and vary the free vibrating lengths thereof.

15. In a stringed musical instrument: a tensioned string structure; a bar having a crested portion, the crest or crests on said portion contacting said string structure; means mounting said bar for pivotal movement with respect to a point so located that movement of said bar causes said crested portion to move generally lengthwise of said string structure, whereby said crest or crests move progressively along the string structure to vary the free vibrating lengths thereof.

16. In a stringed musical instrument: a tensioned string structure; a bar having one or more string contacting crests inclined at an angle with respect to said structure; and means for bodily translating said bar and one or more crests past the string structure in a direction to maintain the inclination of said crest or crests constant, in order to move said crest or crests progressively along the string structure and vary the free vibrating lengths thereof.

17. In a stringed musical instrument: a tensioned string structure; a bar having a string contacting crest, at least a portion of said crest being inclined at a constant angle with respect to said structure; and means for moving said bar in a direction normal to said structure, to move said crest progressively along the string structure and vary the free vibrating lengths thereof.

18. In a stringed musical instrument: a tensioned string structure; a bar having a string contacting crest, at least a portion of said crest being inclined at a constant angle with respect to said structure; and means for moving said bar in a direction substantially normal to the inclination of said crest, to move said crest progressively along the string structure and vary the free vibrating lengths thereof.

JOHN W. MCBRIDE.

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

UNITED STATES PATENTS Number Name Date 2,316,799 McBride Apr. 20, 1943 2,316,800 McBride Apr. 20, 1943 2,364,861 McBride Dec. 12, 1944 2,405,316 McBride Aug. 6, 1946 2,413,062 Miessner Dec. 24, 1946 2,422,360 McBride June 17, 1947