US3686993A

US3686993A - Shoulder strap-operated pitch-changing means for spanish guitars

Info

Publication number: US3686993A
Application number: US105427A
Authority: US
Inventors: Clarence L Fender
Original assignee: Columbia Broadcasting System Inc
Current assignee: CBS Broadcasting Inc; Fender Musical Instruments Corp
Priority date: 1971-01-11
Filing date: 1971-01-11
Publication date: 1972-08-29
Anticipated expiration: 1989-08-29

Abstract

The pitch-changer is mounted in a cavity in the body of a Spanish guitar, and incorporates a second-class lever in the form of a bolt which is adjustably associated with a link, the latter being connected to the string to be tensioned in order to change the pitch thereof. The bolt is pivoted by a bell-crank lever which, in turn, is connected to the shoulder strap for operation thereby. The link is adjustable along the length of the bolt to thus change the degree of pulling of the string in response to a predetermined movement of the bell crank and the bolt. Stop means are provided to limit movement of the bell crank to a predetermined angle, and a torsion spring is provided to counterbalance the weight of the guitar body, the mounting of the torsion spring being such that there is no lateral force against the pivot for the bell crank.

Description

United States Patent [151 3,686,993 Fender v ]Aug.29, 1972 SHOULDER STRAP-OPERATED PITCH- [72] Inventor: Clarence L. Fender, Fullerton, 73 Assignee: Columbia Broadcasting System, Inc.,

1 New. York, N'.Y.

[22 Filed: Jan. 11, 1971 21 Appl. No.1 105,427

.52 us. Cl ..s4/312, 84/313 51 me Cl. ..G10d 3/14 58 Field of ....,.....s4/312, 313

[56] References Cited UNITED STATES PATENTS 1,864,690 6/1932 Guibeaud ..s4/312 3,285,152 11/1966 Fahlenberg et a1. ..5s/21.13 x 3,390,600 7/1968 Kelley, Jr.. ..s4/312 3,437,001 4/1969 Kraft ..s4/313 x 3,512,443 5/1970 Parson et al. ..84/3 1 3 CHANGING MEANS FOR SPANISH GUITARS Primary ExaminerRichard B. Wilkinson Assistant Examiner-Lawrence R. Franklin Attorney-Gausewitz, Carr & Rotheliberg 57 ABSTRACT sociated with a link, the latter being connected to the string to be tensioned in order to change'the pitch thereof. The bolt is pivoted by a bell-crank lever which, in turn, is connected to theqshoulder strap for operation thereby. The link is adjustable along the length of the bolt to thus change the degree of pulling of the string inresponse to a predetermined movement of the bell crank and the bolt. Stop means are provided to limit movement of the bell crankto'a predetermined angle, and a torsion spring is provided to counterbalance the weight of the guitar body, the mounting of the torsion Sp g being such that there is no lateral force against the pivot for the bell crank.

24Claims,9DrawingFigures SHOULDER STRAP-OPERATED PITCH- CIIANGING MEANS FOR SPANISH GUITARS BACKGROUND OF THE INVENTION 1 1. Field of the Invention This invention relates to the field of Spanish guitars which are provided with shoulder strap-operated mechanisms adapted, at will of the guitarist, to change the pitch of one or more strings by a predetermined increment.

2. Description of Prior Art Shoulder strap-operated string pitch changers were, i

to the best knowledge of applicant,-introduced by the invention of US. Pat. No. 3,512,443, issued May 19, 1970. The guitar described in such patent is fully operative to perform the new function described and claimed in such patent. However, the mechanism of r such patent is not commercially practical for mass manufacture. As shown in FIG. 4 of such patent, the

' crank, as limited by stop means, will produce a predetermined desired change (for example, one-half tone) in the pitch of the string. Due to different characteristics of strings which generate different'pitches in a guitar, and also due to the characteristics of strings which are adapted to produce the same pitch (but which vary for production reasons), a certain amount of pivoting of the bell crank will not normally produce the same pitch change for one string as for another. Therefore, unless the guitarist is to be forced to attempt to sense by ear when the desired pitch change has been achieved, as distinguished from pivoting the bell crank through a predetermined distance until a stop means is engaged, it is necessary and important that the guitarist be permitted to tune each string both for the lowestpitch and the highest pitch tone (the latter being normally a one-half tone above the former). The present invention achieves this result in a simple and economical manner, and which permits tuning to be effected from outside the guitar body wherein the mechanism is mounted.

The present invention converts the operative but commercially impractical mechanism of said u.S. Pat. 3,512,443 into a commercially practical, mass producible mechanism having greatly enhanced characteristics relative to ease of playing, tunability, adjustability, wear, and other factors. This is accomplished by the lever, link, connector and other members described below and recited in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a bottom plan view of a Spanish guitar incorporating the shoulder strap-operated pitch-changing means of the present invention;

FIG. 2 is an interior plan view of the mechanism, looking outwardly from the interior of the guitar body, the mechanism being shown in its position prior to pulling on the shoulder strap by the guitarist;

FIG. 3 is a view generally corresponding to portions of FIG. 2, but showing the mechanism in its actuated position after the bell crank has been pulled to its extreme position by the guitarist;

FIG. 4 is an-enlarged sectional view taken along line 4-4 of FIG. 2;

. FIG. 5 is an enlarged longitudinal sectional view taken on line 5-5 of FIG. 2;

FIG. 6 is a fragmentary sectional view along line 6- 6 of FIG. 2;

FIG. 7 is an isometric view of the mechanism, but with the guitar body unshown, and illustrating only a portion of the shoulder strap;

FIG. 8 is a view corresponding generally to portions of FIG. 2, but showing a modified construction wherein two strings of the guitar may be stretched, instead of one string thereof; and

FIG. 9 is a fragmentary sectional view on line 9-9 of FIG. 8.

DESCRIPTION OF PREFERRED EMBODIMENTS:

. Referring particularly to FIG. I, the-mechanism of the invention is incorporated in the'back portion of the body 10 of a Spanish guitar, saidguitar having a neck I 11 at the outer end of which is provided a head-l2. The body 10, is, in the present illustration, a solid wooden body (or plastic)-body although the invention may also be provided in hollow-body guitars.

Body 10 has a face and a back which lie in generally parallel planes (-to which neck 11 is also generally parallel), it being understood that the appendedclaims also apply to guitars wherein the generally parallel face and back are contoured. A plurality of generally parallel guitar strings, normally six, are disposed over neck 11 and over the face of body 10 as shown in my prior US. Pat. no. 3,290,981, issued Dec. 13, 1966. The tension in such strings is regulated by tuning pegs or screws (also shown in such prior patent) on head 12.

It is a feature of the present invention that the great majority of the components of the pitch-changing device are recessed into the back of body'10, and in a recess which is sufficiently small that the body is not weakened substantially but instead may readily withstand the stresses imposed by the strings of the guitar. The recess is numbered 13, and has an outline which is shown by phantom lines 14in FIG. 2. A major portion of the recess 13 is disposed between the neck 11 and the bridge region (describes below) of the guitar.

Provided over a generally L-shaped portion of the recess 13, such portion being relatively adjacent the neck 11 of the guitar, is an L-shaped cover and mounting plate 16. Such. plate 16 is secured to body 10 by means of screws which are represented at 17 (FIG. 6). An operating arm 18 of a bell-crank lever, described below, is mounted exteriorly of the plate 16. Operating arm 18, and the entire bell-crank, are pivotally mounted to the plate 16 (and thus to body 10) by means of a bolt 19 which extends through the arm 18 through the plate 16 and into a large-diameter nut 21 (FIG. 4).

The bolt 19 also extends through the corner or elbow bushing or washer 23 (FIG. 4) between the lever 22 and the interior surface of plate 16.

' The bell-crank lever 22 has an arm 24 which is disposed inwardly adjacent and parallel to the plate 16, and also parallel to the above-indicated operating arm 18. The remaining arm 25 of the bell-crank lever 22 extends at a right angle to arm 24 for operation of a second-class lever as stated below;

Operating arm 18 is fixedly connected to arm 24 of bell-crank lever 22 by means of a bolt 26 (FIG. 4). Such bolt extends inwardly through a slot 27 in plate 16, and through arm 24 of the bell-crank, for threaded connection to an oversize nut 28. The slot 27 has such a length that it permits a predetermined amount of pivotal movement of the bell-crank lever 22 and its operating arm 18 about pivot bolt 19.

Bolt 19 is not threadedly related to plate 16, but is threaded through arm 24 as well as through nut 21. Thus, nut 21 serves as a lock nut. Similarly, bolt 26 is threaded through arm 24, so that nut 28 serves as a lock nut.

It will be seen that the operating arm 18 moves parallel to and conjointly with the arm 24 of the bell-crank 22. Therefore, these two elements may for some purposes both be regarded as portions of the bell-crank.

The

arms

18 and 24 extend generally parallel to the neck 11 of the instrument, being ofiset from such neck in a direction toward the edge 29 (FIG. 1) of the guitar body 10. Such edge 29 is the one held uppermost when the instrument is played by amusician. Arm 25 of the bell-crank extends in a direction away from such edge 29 and toward the longitudinal axis of the neck 11. Thus, the

arms

18 and 24 are generally parallel to but offset laterally from, the strings of the instrument, whereas the arm 25 is transverse to such strings.

The free end of operating arm 18 is provided with a button 31 for connection to the end of the shoulder strap 32 of the guitar. The remaining end of the strap is connected to a button 33 which is fixed on the tail portion of body 10. Thus, as described in the cited US. Pat. No. 3,512,443, pulling on the strap 32 by the neck of the player (or pushing on the body by the arms of the player) causes pivotal movement of operating arm 18 and thus of bell-crank 22.

An elongated second-class lever 35 is disposed transversely of the extended axis of neck 11, that is to say, transversely of the guitar strings, and generally across such extended axis. Lever 35 is thus in general alignment with arm 25. Stated more definitely, the lever 35 is an elongated bolt having a head region 37 (FIG. 6) which is pivotally mounted in an oversize opening 38 formed in a recessed portion 39 of the cover and mounting plate 16. Such recessed portion 39 is disposed on the opposite side of the guitar axis from the bell crank 22, and generally in line with the arm 25 of the bell crank. Thus, the head region 37 is relatively adjacent the lowermost edge (FIG. 1 of the body 10. As best shown in FIG. 6, the recessed portion 39 has an inclined wall 41 which extends inwardly, and a much more sharply inclined wall 42 whichis provided with the opening 38 for the lever bolt.

' The other end of bolt 35, remote from head 37 thereof, extends through an oversize opening 43 (FIG. 6) in a flange 44 provided at the free endof arm 25 of the bell-crank. A nut 46 is mounted on such bolt end, and a helical compression spring 47 is seated between the nut and the flange to maintain the bolt in the proper longitudinal position while permitting the bolt to pivot. An operator employing a screwdriver may rotate the bolt 35 about its own axis from the exterior of the instrument to thus effect an important adjustment as described below. The adjustment is effected without providing an opening through which dirt, etc., may enter the recess 13.

A link 49 is connected at one end to the second-class lever 35 and at the other end to a first-class lever 50 (FIG. 5) which, in turn, is connected to a guitar string 51 the pitch of which is to be changed. The link 49 is disposed in recess '13 parallel to the string 51, that is to say, generally in line with the neck 11. Y

Incorporated in link 49 is a turnbuckle having an internally-threaded body 52 into which is threaded an extemally-threaded element 53 to which a loop 54 of hardened wire is rigidly secured. The loop 54 extends snugly around the second-class lever bolt 35 in such manner that the position of the loop' along the bolt. 35 may be adjusted by turning such bolt. Thus, the wire loop is threadedly related to the bolt. This provides an i extremely simple, economical and mass-producible manner of shifting the connection between the link and the bolt, in response to an operator. employing a tool at the external portion of the'mechanism, whereby relative pivotal movement between the link 49 and the second-class lever 35 is permitted. Stated otherwise, loop 54 forms a highly effective nut and pivot element which is threadedly related to the bolt 35, and which may pivot relative to the bolt as shown in FIGS. 2 and 3.

Another externally-threaded element, numbered 56, is threadedly associated with turnbucklebody 52, being connected with a loop 57 which is removably hooked around the lower end of the first-class lever 50 for operation thereof. A spring 58 is jammed around element 56, and around a portion of body 52, to prevent undesired rotation of these elements relative to each other.

A cover plate 59 is mounted over the portion of v recess 13 in which the link 49 and the lever ends are disposed, being secured in position by screws which are indicated generally at 61 in FIGS. 1-2. Such plate 59 has access openings 62 (FIGS. 1, 5 and 7) therein, there being one such opening beneath each of the six strings of the guitar.

There are six levers 50, one for each string, each such lever being mounted in its own opening 63 through body 10 (such lever openings communicating with recess 13). Each lever also extends through an opening in a bridge plate 64 (FIGS. 5 and 7) which is secured by suitable screws (not shown) to the face of body 10 and over the openings 63. The upper end of each lever 50 is notched at 66 to receive a portion of the bridge plate 64, so that a fulcrum is provided at 67 (FIG. 5) for pivoting of the lever.

A guitar string extends upwardly through a bore 69 in each lever 50, being prevented from movement through the bore by an eyelet or ball 70 at the end of the string. The string extends over a rounded edge 71 of With the described construction, the guitarist may select which string topull by merely hooking the loop 57 over the desired one of the six first-class levers 50. A helical compression spring 77 is mounted in each recess or opening 63 and is seated on the edge of the lever which is closest to neck 11. Such spring insures that the lever 50 will be in theproper position at all times, despite string breakage. Such spring also insures that those levers not associated with loop 54 will remain in proper positions for anchoring of the associated strings.

It is highly important to the pitch-changing device shown in US. Pat. No. 3,512,443, and in the present instrument, that the tension on the string 51 will not change until a change is intentionally effected by the guitarist. Thus, for example, the tension on the string cannot be permitted to change as a result of the weight of the guitar as it merely hangs from its strap 32. It is, therefore, essential that a spring means be provided to maintain operating arm 18 in a predetermined position, despite the weight of the instrument, and until the operator intentionally creates a relative pull between the strap 32 and the instrument to thereby intentionally elongate the string 51. The predetermined position is the one shown in FIGS. 1 and 2, the bolt 26 then being relatively remote from upper edge 29 (FIG. 1) of the body 10.

The present mechanism incorporates a simple, economical and compact spring means which is very easy to assemble with the remaining parts, and which does not exert any strain on the pivot bolt 19 for the bell-crank. In the present mechanism, the spring means is a helical torsion spring 78 which is wrapped around the oversize nut 21 and is maintained on such nut by a flange 79 at the upper surface thereof. One end 78a of the spring extends toward the head 12 of the guitar and seats in an annular groove 81 in the oversize nut 28. The other end 78b of the spring extends generally parallel to such one end and seats in an annular groove 82 in a nut 83 which is secured in recess 13 on the interior surface of plate 16 by means of a bolt 84 (FIG. 4). Thus, the overall configuration of the spring is in the nature of a hairpin.

The spring ends are seated on the sides of the nuts 83 and 28 which are relatively adjacent each other (FIG. 2), and the manner of winding of the spring is such that the natural tendency of the spring is to cause the angle between thespring ends 78a and 78b to increase. Thus, and since the nut 83 is fixed in position on plate 16, the spring normally forces the nut 28 and the bell-crank lever and arm 18 to that end of slot 27 (the abovestated predetermined position) which is lowermost when the guitar is in the playing position.

As shown in FIG. 4, the arms 78a and 78b of spring 78 are disposed at different elevations. Furthermore, the nut 28 is much shorter than the nut 83, the relationship being such that the nut 28 may move beneath spring arm 78b when the mechanism is shifted to the actuating position shown in FIG. 3.

It is pointed out that both of the levers 22 (including operating portion 18) and 35 pivot in a plane which is generally parallel to guitar body 10, that is to say, is generally parallel to the face and back of such body.

MANNER OF ASSEMBLY, AND OPERATION The device is very simple to assemble, by first insertthe stop nut 83 in position. The bolt 19 is then inserted through arm 18, plate 16, bushing 23 and arm 24, following which the nut 21 is mounted over the bolt 19 after first being passed through the helical torsion spring 78. The bolt 26 is inserted through slot 27, and through arm 24, following which nut 28 is mounted into position. It is then a highly simple matter to snap the ends of the spring arms 78a and 78b into theannular grooves 81 and 82 in the. nuts 28 and 83.

The second-class lever bolt 35 is inserted through the oversize opening 38 (FIG. 6) and then through flange 44, after first being passed through the loop 54. The nut 46 and spring 47 are then mounted on the end of the bolt. v

The assembly formed by the plate 16 and associated elements is then secured to the guitar body 10 over the L-shaped recess therein. The levers 50 are then inserted through openings 63 and through bridge plate 64, springs 77 are inserted (FIG. 5), and the loop 57 is hooked over the lever 50 associated with the string 51 I which it is desired to tension. 7

The lower end of each lever 50 is biased by its associated spring 77 against the wall of opening 63 which is remote from the neck 11. All of the levers 50 remain in such position, except the lever which is connected to link 49 and thus to the above-described pitch-changing mechanism.

The loop 54 is initially associated with a midportion of lever bolt 35, as shown in FIGS. 2 and 3. Further more, the turnbuckle incorporated in link 49 is so adjusted (at the factory) that, prior to pulling on strap 32, the associated lever 50 is spaced away from the wall of opening 63 (against the bias of spring 77). Thus, even when the mechanism is in the condition of FIG. 2, the string tension is determined by the engagement of bolt 26 with the end of slot 27. There is no play or lost motion in the entire mechanism.

The operator then tunes the string 51 to thezdesired base pitch, by turning one of the tuning pegs (not shown) on head 12. This is done priorto pulling on strap 32, the mechanism still being in the FIG. 2 position. The operator then actuates the operating arm 18 to the extreme position permitted by the slot 27. Stated otherwise, the mechanism is shifted to the actuated position of FIG. 3. Thereafter, the lever bolt 35 is rotated about its longitudinal axis to shift loop 54 therealong until the tuning of the string 51 is as desired, being normally one-half tone above the tuning of the string when the mechanism is in the FIG. 2 position. The mechanism is then relaxed to the FIG. 2 position, and the base-pitch tuning is again adjusted by turning the tuning screw on head 12. The above-described sequence is, if necessary, repeated until both the base pitch and the elevated pitch are precisely as desired by the musician.

The cover 59 is mounted at the factory, after all factory adjustments have been made. If necessary, and without removing either the plate 16 or the cover plate 59, pitch adjustments may be made (by the musician) in the upper pitch to which the string is tuned when the mechanism is in the actuated position of FIG. 3. This is done by merely rotating the bolt head 37 (FIG. 6), with hole 62 (FIG. and bore 69 and then extended over bridge element 72.

EMBODIMENT OF FIGS. 8 and 9 In the embodiment of FIGS. 8 and 9, parts which correspond to those of the previous embodiment have been given the same reference numerals'In addition, reference characters which generally correspond have been given the same reference numerals as in the previous embodiment, except followed by the letter a or b. The operation and construction of the embodiment of FIGS. 8 and 9 are identical, except as specifically stated, to the operation and construction of the embodiment of FIGS. 1-7.

In the embodiment of FIGS. 8 and 9, the recess 39 (FIG. 6) in the plate 16a is made sufficiently large to receive the heads of two lever bolts 35a and 35b, which bolts extend through the flange 44a at the end of bellcrank arm a. Two turnbuckles or links 49a and 49b are provided, and are respectively associated with the lever bolts 35a and 35b. Thus, two of the levers 50 may be associated with the present mechanism, thereby permitting two strings 51 to be pulled instead of a single string.

Referring particularly to FIG. 9, it is pointed out that the loop 54a extends downwardly over bolt 35a, whereas loop 54b extends upwardly around bolt 35b. Thus, the loops 54a and 54b may be spaced away from each other in order to prevent interference therebetween as a result of turning of the respective bolts 35a and 35b.

The head of bolt 35 is provided with suitable slot means (for example of the Phillips type) adapted to receive the tip of a screwdriver.

A second-class lever is one wherein the fulcrum is at one end, the force is applied at the other end and the load (resistance) is in the middle. A first-class lever is one wherein the fulcrum is in the middle.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

I claim:

1. A Spanish guitar incorporating pitch-changing means operated by the shoulder strap, which guitar comprises:

a guitar body having a neck extended therefrom,

a plurality of guitar strings mounted in tensioned relationship over said neck and over said body,

a lever pivotally mounted on said body,

stop means to limit the pivotal movement of said lever in such manner that said lever may only pivot between first and second predetermined positions angularly offset from each other, i

means to connect said lever to at least one of said strings to effect changing of the tension of said one string in response to pivoting of said lever between said predetermined positions,

said means to connect said lever to said one string comprising a second-class lever pivotally connected to said body and operated bysaid firstmentioned lever,

said means to connect said first-mentioned lever to said one string further comprising a first-class lever connected to said one string,

said means to connect said first-mentioned lever to said one string further comprising a turnbuckle to connect said first-class lever to said secondclass lever,

means to adjust said connector means to achieve a predetermined changingof the pitch of said one string in response to said pivoting of said first-mentioned lever between said predetermined positions,

said means to adjust said connector means comprising means to shift along said second-class lever the connection thereof to said turnbuckle,

a shoulder strap connected at one end to said firstmentioned lever and at the other end to said guitar body, and spring means to bias said first-mentioned lever to said first predetermined position, said spring means being sufficiently strong to prevent the weight of the guitar from shifting said first-mentioned lever away from said first predeterminedposition whereby the guitarist must intentionally operate said shoulder strap to shift said first-mentioned lever to said second predetermined position and thus achieve said predetermined changing of the pitch of said one string. 1 2. The invention as claimed in claim 1, in which said second-class lever is an elongated bolt adapted to be rotated about the longitudinal axis thereof, and in which said means to adjust said connection includes a combination nut and pivot element threadedly associated with said bolt for shifting therealong in response to rotation of said bolt about the longitudinal axis thereof.

3. A Spanish guitar incorporating pitch-changing means operated by the shoulder strap, which guitar comprises:

a guitar body having a neck extended therefrom,

an elongated second-class lever disposed transversely of said strings, one end of said second-class lever being pivotally connected to said body,

said second-class lever being an elongated bolt,

a shoulder strap having one end thereof connected to said body,

means to connect the other end of said shoulder strap to the other end of said second-class lever and in such manner that pulling on said shoulder strap effects pivotal movement of said secondclass lever generally in a plane parallel to said body, and

means to connect an intermediate portion of said second-class lever to at least one of said strings to thus effect changing of the tension in said one string in response to said pivotal movement of said second-class lever,

said means to connect said second-class lever to said one string including a combination pivot and nut element threadedly associated with said bolt for shifting therealong in response to rotation of said bolt about the longitudinal axis thereof,

a said means to connect said second-class lever to said one string further including a first-class lever directly connected to said string, and a link to connect said first-class lever to said combination pivot and nut element.

4. The invention as claimed in claim 3, in which said combination pivot and'nut element is a loop of wire looped around said bolt, and in which said link'includes a turnbuckle adapted tomaintain suflicient tension on said loop of wire to keep the same threadedly associated with said'bolt.

5. Theinvention asclaimed in claim 3, in which-the pivot connection between said one end-of said secondclass lever and said body comprises a pivot element mounted onthebackof said guitarbody and havingan opening therethrough to receive said bolt, said bolt having-a head-disposed on the side of said'pivot element remote'from said other end of said second-class lever, said head being adapted to be rotated by the guitarist to thereby shift said combination pivot and nut element along said bolt.

6. A Spanish guitar incorporating pitch-changing means operated by the shoulder strap, which guitar comprises:

a guitar body having a neck extended therefrom,

a plurality of guitar strings mounted in tensioned relationship over said neck and over said body, said guitar strings being generally parallel to each other,

an elongated externally-threaded element, fulcrum means providedadjacent one end of said externally-threadedelement to'pivotally mount said externally-threaded element to said body,

a shoulder strap havingone end connected .to saidbody, means to connect the other end of said strap to the end of said externally-threaded element remote from said one end thereof,

whereby pulling on said strap by the guitarist effects pivotal movement of said extemallythreaded element about said fulcrummeans, combination nut and pivot means provided on said externally-threaded element between said one end thereof and said remote end thereof, said combination nut and pivot means being a loop of wire threadedly associated with said externally-threaded element and adapted to pivot relative thereto, means to rotate said externally-threaded element about the longitudinal axis thereof to thereby shift said combination nut and pivot means along said externally-threaded element, and means to connect said combination nut and pivot means to at least one of said strings. 7. The invention as claimed in claim 6, in which said means to connect said combination nut and pivot means to said one string includes turnbuckle means to maintain tension on said loop of wire and thus maintain said loop threadedly associated with said externallythreaded element, and further includes lever means connected to said string.

8. The invention as claimed in claim 6, in which said means to rotate said externally-threaded element comprises head means at said one end of said externallythreaded element and adapted to rotate the same about the longitudinal axis thereof.

9. The invention as claimed in claim 6, in which said fulcrum means comprises a fulcrum element fixedly associated with said guitar body, said fulcrum element having an opening therethrough to receive said one end of said externally-threaded element.-

10. The invention as claimed in claim 9, in which said externally-threaded element is mounted in a recess in the back of said guitar body, and in which said fulcrum means is provided on the cover plate for said recess,

. said cover plate being adapted to prevent ingress of dirt into said recess, said externally-threaded element having a head mounted externally of said cover plate for operation by the guitarist to-thereby rotate said externally-threaded element and shift said combination nut and pivot means therealong without removing said cover plate.

11. A guitar incorporating shoulder strap-operated pitch-changing means, which comprises: a guitar body having a neck extended therefrom, a plurality of strings mounted over said neck and said body in tensioned condition, a pivot element fixedly mounted on said body, a lever pivotally connected to said pivot element, a shoulder strap having one end thereof connected to one part of said lever, the other end of said strap being connected to said body, means to connect another part of said lever to at least one of said strings,

whereby to change the tension of said one string in response to pivoting of said-lever by said strap,

a torsion spring mounted around said pivot element,

one end of said spring being engaged with said lever to bias the same to a predetermined position,

the other end of said spring being fixed in position cludes a second lever operated by said first-mentioned lever, a link connected to said second lever, and a third lever connected to said link and also to said one string, said secondand third levers being pivotally associated with said guitar body.

13. The invention as claimed in claim 11, in which stop means are provided to limit the pivotal movement of said lever, said stop means permitting said lever to pivot between said predetermined position and another predetermined position angularly offset therefrom.

14. A Spanish guitar having pitch-changing means operated by the shoulder strap, which guitar comprisesi a solid body having a generally planarface and a generally planar back disposed in spaced and generally parallel relationship to each other,

a neck extended from one end of said body and generally parallel to the planes of said faceand said back, a bridge mounted on said face of said body, a plurality of generally parallel strings mounted in tensioned relationship-over said neck, over said face, and over said bridge, a recess provided in said back of said body, an elongated second-class lever mounted in said recess at a region between said bridge and said neck,

said second-class lever being disposed generally parallel to the planes of said face and said back and also being disposed transverse to said strings, means to pivotally connect one end of said secondclass lever to said body to permit pivotal movement of said lever in a plane generally parallel to the planes of said face and said back, said one end of said second-class lever being relatively adjacent the edge of said body that is held lowermost by the guitarist when the guitar is in playing position, fixed pivot axis provided relatively adjacent the edge of said body that is held uppermost by the guitarist when the guitar is in playing position, a bell crank pivotally connected to said fixed pivot axis, one army of said bell crank lever being generally aligned with said second-class lever and being connected thereto, a shoulder strap connected at one end thereof to the other end of said bell crank, the other end of said shoulder strap being connected to said body, spring means to bias said bell crank to a predetermined pivoted position at which said other end of said bell crank is shifted toward said lowermost edge of said body, said spring means being sufficiently strong to prevent the weight of the guitar from effecting pivoting of said bell crank to shift said other end toward said upper-most edge of said body, a lever extended through said body from said recess to the vicinity of said bridge, said last-mentioned lever being connected to at least one of said strings, and

a link disposed in said recess and connected between said last-mentioned lever and an intermediate region of said second-class lever between said one end thereof and said other end thereof.

15. The invention as claimed in claim 14, in which said second-class lever is an elongated threaded element, in which said means to pivotally connect said one end of said second-class lever to said body is adapted to permit rotation of said threaded element about the longitudinal axis thereof, in which means are provided to permit the guitarist to rotate said threaded element about said longitudinal axis thereof, and in which said link is connected to said second-class lever by a combination threaded element and pivot means whereby said connection between said link and said threaded element shifts along said threaded element in response to rotation thereof, and whereby said threaded element may pivot relative to said link upon shifting of said second-class lever by said bell crank.

16. The invention as claimed in claim 14, in which a cover plate is mounted over said recess, in which said means to pivotally connect said one end of said secondclass lever to said body comprises a recessed portion of said cover plate, and in which said second-class lever is a bolt which extends through an oversize opening in said recessed portion of said cover plate, said bolt having a head disposed exteriorly of said cover plate for access by the guitarist.

17. The invention as claimed in claim 14, in which said means to connect said one end of said bell crank to the other end of said second-class lever comprises a flange on said bell crank and having an opening therein through which said second-class lever extends, said second-class lever being externally threaded, and in which a nut is provided on said second-class lever ad-' jacent said flange.

18. The invention as claimed in claim 14, in which said link includes a turnbuckle, in which said secondclass lever is an externally threaded element, and in which said link further includes a loop of wire extended from said turnbuckle around said externally threaded element and forming a combination nut and pivot means permitting shifting of said wire along said second-class lever in response to rotation of said lever about the longitudinal axis thereof.

19. The invention as claimed in claim 14, in which an additional link is provided and is connected to a lever connected with another of said strings, in which an ad- Y ditional second-class lever is provided and connected to said bell crank, and in which said additional link is pivotally associated with said additional second-class lever.

20. The invention as claimed in claim 14, in which a cover is provided for said recess, said cover having a slot therein, in which said bell crank has an exterior portion disposed beneath said cover and connected to said shoulder strap, said exterior portion of said bell crank being pivotally connected to said fixed pivot axis,

in which said bell crank has an interior angular portion disposed in said recess and above said cover, and in which an element is extended between said exterior and interior portions of said bell crank and through said slot, said last-named element cooperating with the ends of said slot to limit the pivotal movement of said bell crank, said bell crank being in said predetermined position when said element is at one end of said slot and being in an other predetermined position when said bell crank is at the other end of said slot.

21. The invention as claimed in claim 20, in which said fixed pivot axis is a bolt extended through said exterior portion of said bell crank, through said cover plate and through said interior portion of said bell crank, and in which an enlarged nut is provided in said recess around said bolt and on the opposite side of said interior portion from said cover plate.

22. The invention as claimed in claim 21, in which a helical torsion spring is provided around said enlarged nut, in which said element which extends through said slot is a second bolt, in which a second enlarged nut is threadedly associated with said second bolt on the side of said interior portion remote from said cover plate, in which said torsion spring has an arm which extends into bearing engagement with said second nut, in which a third nut is mounted on said cover plate and in said recess, and in which a second arm of said torsion spring engages said third nut.

23. The invention as claimed in claim 14, in which said lever extended through said body has a passage bridge is adjustably mounted on a plate disposed on the face of said body, said plate having an opening therethrough to receive said lever and said string therethrough, and in which said lever is adapted to pivot on one edge of said opening.

24. A Spanish guitar incorporating pitch-changingmeans operated by the shoulder strap, .which guitar comprises:

a guitar body having a neck extended therefrom, a plurality of guitar strings mounted in tensioned relationship over said neck and over said body,

I an elongated second-class lever disposed transverse- 1y of said strings, one end of said second-class lever being pivotally connected to said body,

a shoulder strap having one end thereof connected to i said body,

means to connect the other end of said shoulder one arm of said bell crank lever being generally aligned with said second-class lever and being connected thereto, and means to connect an intermediate portion of said second-class lever to at least one of saidstrings to thus effect changing of the tension in said one string in response to said pivotal movement of said second-class lever.

Claims

1. A Spanish guitar incorporating pitch-changing means operated by the shoulder strap, which guitar comprises: a guitar body having a neck extended therefrom, a plurality of guitar strings mounted in tensioned relationship over said neck and over said body, a lever pivotally mounted on said body, stop means to limit the pivotal movement of said lever in such manner that said lever may only pivot between first and second predetermined positions angularly offset from each other, means to connect said lever to at least one of said strings to effect changing of the tension of said one string in response to pivoting of said lever between said predetermined positions, said means to connect said lever to said one string comprising a second-class lever pivotally connected to said body and operated by said first-mentioned lever, said means to connect said first-mentioned lever to said one string further comprising a first-class lever connected to said one string, said means to connect said first-mentioned lever to said one string further comprising a turnbuckle to connect said firstclass lever to said second-class lever, means to adjust said connector means to achieve a predetermined changing of the pitch of said one string in response to said pivoting of said first-mentioned lever between said predetermined positions, said means to adjust said connector means comprising means to shift along said second-class lever the connection thereof to said turnbuckle, a shoulder strap connected at one end to said first-mentioned lever and at the other end to said guitar body, and spring means to bias said first-mentioned lever to said first predetermined position, said spring means being sufficiently strong to prevent the weight of the guitar from shifting said first-mentioned lever away from said first predetermined position whereby the guitarist must intentionally operate said shoulder strap to shift said first-mentioned lever to said second predetermined position and thus achieve said predetermined changing of the pitch of said one string.

2. The invention as claimed in claim 1, in which said second-class lever is an elongated bolt adapted to be rotated about the longitudinal axis thereof, and in which said means to adjust said connection includes a combination nut and pivot element threadedly associated with said bolt for shifting therealong in response to rotation of said bolt about the longitudinal axis thereof.

3. A Spanish guitar incorporating pitch-changing means operated by the shoulder strap, which guitar comprises: a guitar body having a neck extended therefrom, a plurality of guitar strings mounted in tensioned relationship over said neck and over said body, an elongated second-class lever disposed transversely of said strings, one end of said second-class lever being pivotally connected to said body, said second-class lever being an elongated bolt, a shoulder strap having one end thereof connected to said body, means to connect the other end of said shoulder strap to the other end of said second-class lever and in such manner that pulling on said shoulder strap effects pivotal movement of said second-class lever generally in a plane parallel to said body, and means to connect an intermediate portion of said second-class lever to at least one of said strings to thus effect changing of the tension in said one string in response to said pivotal movement of said second-class lever, said means to connect said second-class lever to said one string including a combination pivot and nut element threadedly associated with said bolt for shifting therealong in response to rotation of said bolt about the longitudinal axis thereof, said means to connect said second-class lever to said one string further including a first-class lever directly connected to said string, and a link to connect said first-class lever to said combination pivot and nut element.

4. The invention as claimed in claim 3, in which said combination pivot and nut element is a loop of wire looped around said bolt, and in which said link includes a turnbuckle adapted to maintain sufficient tension on said loop of wire to keep the same threadedly associated with said bolt.

5. The invention as claimed in claim 3, in which the pivot connection between said one end of said second-class lever and said body comprises a pivot element mounted on the back of said guitar body and having an opening therethrough to receive said bolt, said bolt having a head disposed on the side of said pivot element remote from said other end of said second-class lever, said head being adapted to be rotated by the guitarist to thereby shift said combination pivot and nut element along said bolt.

6. A Spanish guitar incorporating pitch-changing means operated by the shoulder strap, which guitar comprises: a guitar body having a neck extended therefrom, a plurality of guitar strings mounted in tensioned relationship over said neck and over said body, said guitar strings being generally parallel to each other, an elongated externally-threaded element, fulcrum means provided adjacent one end of said externally-threaded element to pivotally mount said externally-threaded element to said body, a shoulder strap having one end connected to said body, means to connect the other end of said strap to the end of said externally-threaded element remote from said one end thereof, whereby pulling on said strap by the guitarist effects pivotal movement of said externally-threaded element about said fulcrum means, combination nut and pivot means provided on said externally-threaded element between said one end thereof and said remote end thereof, said combination nut and pivot means being a loop of wire threadedly associated with said externally-threaded element and adapted to pivot relative thereto, means to rotate said externally-threaded element about the longitudinal axis thereof to thereby shift said combination nut and pivot means along said externally-threaded element, and means to connect said combination nut and pivot means to at least one of said strings.

7. The invention as claimed in claim 6, in which said means to connect said combination nut and pivot means to said one string includes turnbuckle means to maintain tension on said loop of wire and thus maintain said loop threadedly associated with said externally-threaded element, and further includes lever means connected to said string.

8. The invention as claimed in claim 6, in which said means to rotate said externally-threaded element comprises head means at said one end of said externally-threaded element and adapted to rotate the same about the longitudinal axis thereof.

9. The invention as claimed in claim 6, in which said fulcrum means comprises a fulcrum element fixedly associated with said guitar body, said fulcrum element having an opening therethrough to receive said one end of said externally-threaded element.

10. The invention as claimed in claim 9, in which said externally-threaded element is mounted in a recess in the back of said guitar body, and in which said fulcrum means is provided on the cover plate for said recess, said cover plate being adapted to prevent ingress of dirt into said recess, said externally-threaded element having a head mounted externally of said cover plate for operation by the guitarist to thereby rotate said externally-threaded element and shift said combination nut and pivot means therealong without removing said cover plate.

11. A guitar incorporating shoulder strap-operated pitch-changing means, which comprises: a guitar body having a neck extended therefrom, a plurality of strings mounted over said neck and said body in tensioned condition, a pivot element fixedly mounted on said body, a lever pivotally connected to said pivot element, a shoulder strap having one end thereof connected to one part of said lever, the other end of said strap being connected to said body, means to connect another part of said lever to at least one of said strings, whereby to change the tension of said one string in response to pivoting of said lever by said strap, and a torsion spring mounted around said pivot element, one end of said spring being engaged with said lever to bias the same to a predetermined position, the other end of said spring being fixed in position relative to said body, said spring being sufficiently strong that the weight of the guitar will not shift said lever away from said predetermined position.

12. The invention as claimed in claim 11, in which said means to connect said lever to said one string includes a second lever operated by said first-mentioned lever, a link connected to said second lever, and a third lever connected to said link and also to said one string, said second and third levers being pivotally associated with said guitar body.

14. A Spanish guitar having pitch-changing means operated by the shoulder strap, which guitar comprises: a solid body having a generally planar face and a generally planar back disposed in spaced and generally parallel relationship to each other, a neck extended from one end of said body and generally parallel to the planes of said face and said back, a bridge mounted on said face of said body, a plurality of generally parallel strings mounted in tensioned relationship over said neck, over said face, and over said bridge, a recess provided in said back of said body, an elongated second-class lever mounted in said recess at a region between said bridge and said neck, said second-class lever being disposed generally parallel to the planes of said face and said back and also being disposed transverse to said strings, means to pivotally connect one end of said second-class lever to said body to permit pivotal movement of said lever in a plane generally parallel to the planes of said face and said back, said one end of said second-class lever being relatively adjacent the edge of said body that is held lowermost by the guitarist when the guitar is in playing position, a fixed pivot axis provided relatively adjacent the edge of said body that is held uppermost by the guitarist when the guitar is in playing position, a bell crank pivotally connected to said fixed pivot axis, one arm of said bell crank lever being generally aligned with said second-class lever and being connected thereto, a shoulder strap connected at one end thereof to the other end of said bell crank, the other end of said shoulder strap being connected to said body, spring means to bias said bell crank to a predetermined pivoted position at which said other end of said bell crank is shifted toward said lowermost edge of said body, said spring means being sufficiently strong to prevent the weight of the guitar from effecting pivoting of said bell crank to shift said other end toward said upper-most edge of said body, a lever extended through said body from said recess to the vicinity of said bridge, said last-mentioned lever being connected to at least one of said strings, and a link disposed in said recess and connected between said last-mentioned lever and an intermediate region of said second-class lever between said one end thereof and said other end thereof.

16. The invention as claimed in claim 14, in which a cover plate is mounted over said recess, in which said means to pivotally connect said one end of said second-class lever to said body comprises a recessed portion of said cover plate, and in which said second-class lever is a bolt which extends through an oversize opening in said recessed portion of said cover plate, said bolt having a head disposed exteriorly of said cover plate for access by the guitarist.

17. The invention as claimed in claim 14, in which said means to connect said one end of said bell crank to the other end of said second-class lever comprises a flange on said bell crank and having an opening therein through which said second-class lever extends, said second-class lever being externally threaded, and in which a nut is provided on said second-class lever adjacent said flange.

18. The invention as claimed in claim 14, in which said link includes a turnbuckle, in which said second-class lever is an externally threaded element, and in which said link further includes a loop of wire extended from said turnbuckle around said externally threaded element and forming a combination nut and pivot means permitting shifting of said wire along said second-class lever in response to rotation of said lever about the longitudinal axis thereof.

19. The invention as claimed in claim 14, in which an additional link is provided and is connected to a lever connected with another of said strings, in which an additional second-class lever is provided and connected to said bell crank, and in which said additional link is pivotally associated with said additional second-class lever.

20. The invention as claimed in claim 14, in which a cover is provided for said recess, said cover having a slot therein, in which said bell crank has an exterior portion disposed beneath said cover and connected to said shoulder strap, said exterior portion of said bell crank being pivotally connected to said fixed pivot axis, in which said bell crank has an interior angular portion disposed in said recess and above said cover, and in which an element is extended between said exterior and interior portions of said bell crank and through said slot, said last-named element cooperating with the ends of said slot to limit the pivotal movement of said bell crank, said bell crank being in said predetermined position when said element is at one end of said slot and being in an other predetermined position when said bell crank is at the other end of said slot.

23. The invention as claimed in claim 14, in which said lever extended through said body has a passage therethrough to receive said one string, in which said bridge is adjustably mounted on a plate disposed on the face of said body, said plate having an opening therethrough to receive said lever and said string therethrough, and in which said lever is adapted to pivot on one edge of said opening.

24. A SPanish guitar incorporating pitch-changing means operated by the shoulder strap, which guitar comprises: a guitar body having a neck extended therefrom, a plurality of guitar strings mounted in tensioned relationship over said neck and over said body, an elongated second-class lever disposed transversely of said strings, one end of said second-class lever being pivotally connected to said body, a shoulder strap having one end thereof connected to said body, means to connect the other end of said shoulder strap to the other end of said second-class lever and in such manner that pulling on said shoulder strap effects pivotal movement of said second-class lever generally in a plane parallel to said body, said means to connect said other end of said shoulder strap to said other end of said second-class lever comprising a bell crank lever pivotally connected to said body, one arm of said bell crank lever being generally aligned with said second-class lever and being connected thereto, and means to connect an intermediate portion of said second-class lever to at least one of said strings to thus effect changing of the tension in said one string in response to said pivotal movement of said second-class lever.