US2973682A

US2973682A - String tension controlling means for lute-type instrument

Info

Publication number: US2973682A
Application number: US673309A
Authority: US
Inventors: Clarence L Fender
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-07-22
Filing date: 1957-07-22
Publication date: 1961-03-07
Anticipated expiration: 1978-03-07

Description

March 7, 1961 2,973,682

' STRING TENSION CONTROLLING MEANS FOR LUTE-TYPE INSTRUMENT Filed July 22, 1957 C-LFENDER 3 Sheets-Sheet 1 QAea/c'Z l. t/0.5a

INVENTOR.

March 7, 1961 c. L. FENDER STRING TENSION CONTROLLING MEANS FOR LUTE-TYPE INSTRUMENT Filed July 22, 1957 5 Sheets-Sheet 2 March 7, 1961 c. L- FENDER 2,973,682

STRING TENSION CONTROLLING MEANS FOR LUTE-TYPE INSTRUMENT Filed July 22, 1957 I 3 Sheets-Sheet 3 INVENTOR.

United States Patent LUTE-TYPE INSTRUMENT Clarence L. Fender, 2212 E. Revere, Fullerton, Calif.

, Filed July 22, 1957, Ser. No. 673,309

25 Claims. (Cl. 84-312) STRING TENSION CONTROLLING MEANS FOR operation, in that they may only adjust the tension of a,

few strings and then only' in a restricted manner. Such device's, and-also those devices adapted to adjust the tension of a substantialvnumber of strings, are frequently characterized by the mere use of balanced springs (with: out fixed stops) -'to maintain the strings in a neutral position, in combination with-means for tensioning or rehiring the strings relative tothe neutral position. Such use of balanced resilient means to maintain the strings in a neutral position, in the .absenceof fixed stops, is not accurate-in that such neutral positonfrequently varies from the true pitch because of variations in the character istics of the resilient means; I I

In attempting to overcome-the above defects, certain prior art workers have-devised mechanisms in. which the neutral string positions are relatively fixed, and;in which separate foot pedals or other means are employed toincrease and decrease the tension of a particular string.

Such mechanisms,-howe'ver, are complicated in construetion in that they incorporate large numbers of levers and pivot points. Such levers are pivoted by pivot pins'to the frame of the instrument, are relatively intricate in shape, and are formed as castings. This complicated construction has the effect of greatly increasing the expense and bulk of the instrument. Furthermore, and very importantly, the large number of pivot points, the use of set'screws for actuating the pivot levers, and other factors, has the effect of increasing the etiects of wear at all points in the lever system. Such wear necessarily results in variations in the musical characteristics of the instrument.

In view of the above and other factors characteristic of conventional musical instruments of the lute. type, and string tension adjusting means therefor, it is an object of the present invention toprovide an improved lute-type instrument and string tension controlling means which is extremely simple in construction, assembly and operation, yet which will produce all of the desirable results achieved by prior art instruments and will also achieve new results.

A further object is to provide a lute-type instrument andstring tension controlling means in which the effects of wear are'minimized or substantially eliminated, so that the musical characteristics of the instrument will remain substantially constant with the passage of time.

' A further object is to provide a string tension controlling means in which the neutral string positons are positively fixed for maintenance of musical accuracy and pitch perfection, and in which note slurrying may be accomplished while the strings are active.

, An additional objectis to provide a string tension con- Patented Mar. 7, 1961 2 trolling apparatus making use'of simple stamped parts stead of expensive castings, I

A further object is to provide a string tension controlling mechanism in which only one pivot pin is required for each string yet in which the string may be either tensioned or relaxed relative to a fixed neutral position, such pivot pin being employed to connect two simple levers which may be sub-assembled together by such pin and without the necessity of employing an additional pin to connect the levers to the frame-of the instrument during final assembly.

A further object is to provide string tension adjusting means in which the components at the string ends are constructed as hardened steel stampings for maximum wear resistance.

Another object is to provide string tension adjusting means incorporating novel stop and actuating means, and in which set screw abrasion is not a factor in wear.

A further object is to provide string tension adjusting means incorporating novel adjustable pedals which may be regulated in elevation relative to other pedals in the instrument, and in which there is no play between the pedals and the strings.

Another object is to provide string tension controlling means in which the degree of sharping or fiatting of each string, from a fixed'neutral position, may be adjusted in a simplemanner and with extreme accuracy.

An additional object is to'provide an instrument in which the cables from the foot pedals to the string tension levers may be shifted from one lever to another with extreme ease, in which a number of such cables may be connected to the tension lever for a single string, and in which the shifting of a single foot pedal may operate to effect sharping of one string and flatting of another.

An additional object is to provide a lute-type instrument in which the fulcrum of a lever for each string operates as a knife edge for simplicity of construction and assembly, and forminimum wear.

Another object is to provide a lute-type instrument in which-the pull for adjusting string tension is longitudinal combination with equalizing means to insure that the levers for such several strings are shifted by desired amounts'controlled only by the adjustable stop means associated with such strings.

These and other objects and advantages of the invention will be more fully set forth in the following specification and claims, which are to be considered in connection with the attached drawings to which they relate.

In the drawings:

Figure l is a perspective illustration of an electric steel guitar constructed in accordance with the present invention;

Figure 2 is an enlarged, fragmentary vertical sectional view taken on line 2-2 of Figure 1 and illustrating a foot pedal mechanism;

Figure '3 is a fragmentary horizontal section taken on line 3 3 of Figure 2;

Figure 4 isan enlarged plan view of one tail portion of the instrument, a part of the cover plate being broken Figure 5 is a verticalsectional viewon line 5--5 of Figure. 4, the string tension controlling levers being illustrated in their normal positons assumed when the pedals are not operated;

Figure .6 is a fragmentary horiz'ontalsection on line 6-6 of Figure 5, illustrating certain of the adjustable stop elements which control the. amount by which the strings may be sharped or flatted; Figure 7 is a fragmentary view which corresponds to a portion of Figure but illustrates the rotated position of a string tension controlling lever assumed when the associated string has been sharped; I

Figure 8 is a similar view except that itv illustrates the positions of the levers assumed when the associated string has been flatted:

Figure 9 is a fragmentary vertical transverse sectional view on line 9-9 of Figure 5, illustrating one pair'of string tension controlling levers;

Figure 10 is a greatly enlarged fragmentary longitudinal sectional view illustrating the knife-edge action between ogre tension controlling lever and the associated fulcrum B Figure 11 is aschematic view illustrating the connecting means between one foot pedal and several stringtension controllingv levers; and.

Figure 12 is a schematic view taken generally on line 1212 of Figure 1 and illustrating the cable means and sheaves which connect the bell crank levers .to the string tension controlling levers.

Referring to the drawings, and particularly to Figure 1, the illustrated instrument isv a dual-type electric steel guitar, and may be seen to. comprise generally a rigid metal frame 10 whichis rectangular in shape and is .sup-

ported at itscorners by adjustable and removable legs 11. Frame 10, which has downwardly extending flanges 12 adapted to mount and conceal sheave and cable connecting elements to bedescribed hereinafter, supports-or mounts two corresponding body elements .13 and 14 a e I ,97356,83

which comprise blocksof hardwood. Each body block is provided longitudinally thereof with a finger board 16 over which eight strings 17 are mounted in a horizontal plane and in parallel.relationship. .The stringsn17for each body block are tensionedacross bridges 18 and .19. .BridgeIS, disposedfto. the left as viewed .in Figure. 1, is mounted adjacent the tuning pegs. 21 which may be of conventional construction. Bridge 19 is disposed at the other end of the instrument, to therig'ht as. viewed. in Figure 1, and is adjustable in construction aswill beldescribed hereinafter. The strings 17 are .slid. for slight distances over the bridge 19 during operation of the string tension controlling means, which forms the essence of the present invention and which will be described in detail below. i

Although the illustrated instrument of -the dual or double type, it is to be understood that a majority of the elements of the present invention are operable on a semblies 26 for operating the same, and foot pedal means 28 for operating the connector means 27.

It is. emphasized that there is one lever assembly' 26 for each of the body blocks 13' and 14, andthat the connector means 27 and foot pedal means 28 serve both such lever assemblies. blocks 13 and 14 are identical, only one (associated with body block 14) will be illustrated and described in detail.

I Construction lever assemblies. 26 I The lever assembly '26 for each body bl ck 3 nd Since the lever assemblies 26 for the body.

14. is best illustrated in Figures 4-10, and comprises upper and

lower plates

31 and 32, respectively, a set of

levers

33 and 34 associated with each of the strings 17 and mounted in cooperating relation with the plates, a spring 36 associated with the levers in each set, and adjustable stop means 37 and 38 associated, respectively, with the levers 33 and Min each set.

The upper plate 31 is formed of hardened steel and is relatively thin, being preferably chrome plated for purposes of appearance. Plate 31 is secured by means of screws 39 to the upper horizontal surface of body block 14 at the tail portion of the instrument, and serves as the cover for a rectangular opening 41 through the body block. The adjustable bridge 19. is mounted on the upper surface of plate 31 by means of horizontal screws 42 which are threaded through the ends thereof and rotate in ears 43' bent up from the plate. Helical compression springs 44 are provided around the screws 42 to maintain the bridge 19 spaced away from the ears, the arrangement being such that rotation of the screws changes the bridge. location and thus the pitch of the strings '17. A metal cover plate 46, preferably chrome plated, is pivoted at 4'7 (Figured) on the pointed ends of bridge 19, which is cylindrical in shape, so that the cover plate may pivot upwardly (counterclockwise in FigureS). when it is desired to expose the upper ends of

thelevers

33 and 34 01 to rotate the adjustment screws 42.

Lowerplate 32, also formed of hardened steel, is mounted parallel to upper plate '31 onthe lower surface of the body block and bymeans of screws 48 (Figure 5).. Plate 32 covers the lower end of openingj41, and also covers a recess or channel 4 9 which is formed in the lower portion of body .block 14 from the opening 41 .to the extreme outer endof the body block. The recess. 49 serves to receive the adjustable stop .means .37 and 38, as will be described in detail hereinafter. Ears 5 1 are formed on' the right edge of lower plate 32, as viewed in Figure 5, to provide supports .or. connectors for one end of the spring 36 associated'with each set of levers 33 and34.' m

Tl1e levers'33 and 34 are generally rectangular hardened steel starnpings and, as .above indicated, are provided one" set for each of the'strings 17. The upper portions of the levers '33 and 34 in each set are in flatwise engagement with each iother (Figure 9), and extend upwardly through a slot 52 in upper plate .31. The lower endsof the levers are spaced apart and extend through

separate slots

53 and 54 in the lower plate 32. vSuch spacing between the lower-portions of the levers in each set takes place at a break 56 between the upper-and lower lever portions. The sides of the levers are in Close but sliding engagement with the slot walls, so that the slots serve in an accurate manner to guide the movement of the levers.

' From the above it will be understood that there are eight parallel and corresponding slots 52 in the upper plate 31, one for each set of levers-33 and 3d. There are 16 parallel and corresponding slots in lower plate 32, eight slots 53 for the levers 33 and eight slots 54 for the levers 34 The set .of

levers

33 and 34 for each string 17. is

identical with the set of levers for each other string. This being the case, the following detailed description will relatei to only one .set of levers for only one string 17, and'will' also relate to the associated three slots 52-54 stop means 37' and 3.8,.spring 3.6, etc., for such one string.

The first lever 33 in each set is formed at its upper end with a notch 57 which-fits against the inner or front end :wall of slot 52. As illustrated in the greatly enlarged Figure '10, notch 57 has walls which .come together at an angle somewhat greater than degrees, so that the apex of the notch rocks around the'lower or fulcrum portion 58 of the inner end wall of the slot 52. This knife-edge actionbetween the apex of notch 57 and the" fulcrum portion'58 provides extreme accuracy with minimized wear, so that the musical characteristics of the instrument do not alter appreciably with time.

. To the rear, or outwardly, of notch 57 the first lever 33 curves upwardly at 59 to form a head, the latter serving to add strength and rigidity to the end of the lever. The outer, vertical edge of the first lever 33, and also second lever 34, is spaced away from the outer or rear end wall of slot 52 so that there is no interference therebetween.

' The lower end of the first lever 33 is formed with a notch 61 adapted to receive in removable relationship a connecting loop portion 62 of the connector means 27. A retaining portion 63 is integrally provided on the lever below the connecting loop portion 62, to prevent the latter fromslipping downwardly out of place. To the rear of the retaining portion 63 is provided a depending ear 64 which is apertured to receive one end of the spring 36. Spring 36 is a helical tension spring and extends to the associated car 51 (Figure 5) previously indicated.

The second lever 34 in each set comprises a head portion 66 which curves upwardly and forwardly and is apertured to receive the end of string 17, the latter being held in position by an eyelet 67 around which the string is looped. Below head portion 66, the second lever 34 is provided with a notch 68 which is sufliciently deep that the second lever never comes into interfering engagement with the inner or forward end wall of slot 52, Le, with the fulcrum portion 58. The lower end of the second lever 34 corresponds to the lower end of the first lever 33 and is correspondingly numbered, except that there is no depending ear 64 and associated spring.

The first and

second levers

33 and 34 are pivotally connected to each other by means of a rivet 69, formed of steel, and located below the fulcrum portion 58 but relatively adjacent upper plate 31. In the illustrated form, the eyelet connection between head portion 66 and string 17 is spaced above the upper plate 31 by a distance slightly less'than the spacing of pivot connection 69 below such plate. The pivot connection or rivet 69 is, however, spaced a very much greater distance above the lower-plate 32, which distance is shown as being on the order of seven times the distance between the rivet and the upper plate.

Referring to Figure 5, the levers are shown in their normal positions, assumed when no tension is applied to the connector means 27 by the foot pedal means 28. The tension of string 17 then operates through second lever 34 and rivet 69 to hold the apex of notch 57 of first lever 33 against the fulcrum portion 58 (Figure of plate 31. Such string tension also operates to maintain the rear edge of the lower portion of the second lever 34 against the wall .at the outer end of its slot 54, at point 70, which acts as a positive stop. The spring 36 operates through ear 64 to maintain the lower rear portion of the first lever 33 against the wall at the end of its slot 53, such slot wall also acting as a stop. The tension on the string 17, when in neutral position, is thus positively and accurately determined by the hardened steel

elements comprising plates

31 and 32 and the levers, and does not vary with the tension of spring 36 or other factors. It follows that a perfect pitch may be achieved, by adjustment of the tuning pegs 21, and that such pitch will be maintained at all times when the string tension controlling means is not operated. This pitch may be referred to as the neutral pitch.

When it is desired to tension the string 17 by an increased amount, to thus raise its pitch, the second lever 34 is pivoted clockwise from the position shown in Figure 5 to that shown in Figure 7. Such pivoting is effected by application of tension to the looped portion 62, as will be described below, and may continue until the stop means 38 is engaged. The eyelet 67 then moves to the right from the position shown in Figure 5 to that shown in Figure 7, to increase the tension on string 17, and raise accessible portion of the instrument.

its pitch by an amount determined by the adjustable stop means 38, such amount normally being a half tone. Dur ing this movement the first lever 33 remains absolutely stationary since the tension of string 17 is sufficient to maintain notch 57 against fulcrum portion 58, and since there is nothing to overcome the tension of spring 36.

When it is desired to lower the pitch of string 17, the

levers

33 and 34 are shifted from the positions shown in Figure 5 to those shown in Figure 8. This is accom-' plished by rotating the first lever 33 clockwise (by pulling its loop 62) for a distance determined by its adjustable stop 37. Such clockwise movement of the first lever 33 has the effect of moving the rivet 69 forwardly, to the position shown in phantom in Figure 10, since the rivet 69 is between the fulcrum 58 and the lower end of the lever 33 to which force is applied. When the rivet 69 moves forwardly, the head 66 of the second lever 34 also moves forwardly to relax the tension on string 17 and thus lower its pitch as desired. It is pointed out that although the first lever 33 pivots clockwise due to application of tension to its connecting loop 62, the second lever 34, to which string 17 is directly connected, pivots counterclockwise about a point at the lower end thereof. The

levers

33 and 34 thus rotate in opposite directions when the string 17 is relaxed.

To summarize the above, it is pointed out that the lever 34 operates as a first class lever during tcnsioning of the string from the Figure 5 position to the position shown in Figure 7. The resistance is present at 17, the fulcrum is at 69 and the force is applied at the lower end of lever 34 by means of a loop 62. The lever 33, on the other hand, operates as a second class lever in that the fulcrum is at 58 (Figure 10), the resistance at 69 and the force at the lower end of lever 33 applied by another loop 62. Such second class lever action of lever 33 takes place during the lessening of the tension on the string 17, as the parts are shifted from the Figure 5 positions to the positions shown in Figure 8. During such shifting to the Figure 8 positions the lever 34 acts as a third class lever in that the resistance is present at the string 17, the force is applied at rivet 69 by the lever 33, and the fulcrum is located at the lower portion of the lever 34 at the outer rear end wall 70 of slot 54. The fulcrum 70 is a sliding one, the actual pivot axis of the lever 34 during shifting of the components from the Figure 5 positions to the Figure 8 positions being in the region of the intersection of slot 54 with the forward or inner vertical edge of lever 34.

The adjustable stop means 37 and 38 are mounted in the previously described recess or channel 49 and in the lower end of opening 41, being supported by the downwardly extending flange 71 of an angle bracket 72 secured at the outer end of channel 49. Each adjustable stop means comprises a metal sleeve 73 in which is secured, for example by soldering, an elongated loop 74 formed of hardened steel. The arms of the loop extend forwardly from sleeve 73 on opposite sides of the associated

lever

33 or 34, so that the base of the loop is disposed inwardly or forwardly of the inner edge of the lever and serves as a stop therefor. An adjustment screw 76 is rotatably mounted in flange 71 and extends inwardly for threading into the outer end of sleeve 73, there being a helical compression spring 77 mounted around the screw 76 to maintain the sleeve 73 and loop 74 in the innermost positions permitted by the screw adjustment. The frame flange 12 at the tail portion of the instrument is provided with slots 78 (Figure l) for access to the adjustment screws 76.

The tuner or player may adjust any of the stop means 37 or 38 by merely rotating the associated screw 76.

The amount of raising or lowering of the pitch of each string is thus positively determined in a simple manner, by means of an adjustment which is performed at a highly The screws 76 may be colored alternately black and white, so that the tuner may readily determine Whether the screw is associated with a first lever 33 or a second lever 34. p o o Thedescribed construction of each lever assembly 26 is simple and economicahyet musically accurate and long lasting. In assembling the unit, the upper cover plate 31 may first be mounted in position by means of the screws 39. Thereafter, the first and

second levers

33 and 34, having been previously sub-assembled by means of the rivet 69, are merely moved into position with their head portions 59 and 66 extending through slots 52. The stop means 38 and 37 are then mounted over the lower ends of the levers, and the lower plate 32 is mounted in position. Springs 36 are then connected, and the loops 62 are mounted in notches 61. Strings 17 are, of course, mounted and tightened at a suitable point in the operation.

It is emphasized that only one pivot pin need be provided, in the form of the rivet 69 which connects the two

levers

33 and 34 for each string. There is no need for a pivot pin to connect the lever assemblies to the body block 14 or other fixed portion of the instrument, which greatly facilitates the assembly operation and reduces the amount of wear caused by operation of the levers. The

levers

33 and 34 are, in effect, held in a floating condition by means of the strings 17 and springs 36, being accurately guided by the

slots

53 and 54 and by certain ends thereof which serve as stops or fulcrum points.

Construction of the connector means 27 between lever assemblies 26 and foot pedal means 28 Referring particularly to Figures 11 and 12, the connector means 27 comprises lever means 79 mounted on frame flange 12 above foot pedal means 28, stationary sheaves or pulleys 30 mounted on flange 1-2 at the end of the instrument remote from the lever assemblies 26, and movable sheaves or pulleys 82 disposed between stationary sheaves 8t and the lever assemblies. Cables 83 extend from the levers 79 around stationary sheaves 80 to movable sheaves 82, and cable yokes 84 connect the movable sheaves to the

levers

33 and 34.

In greater detail, the levers 79 are bell cranks mounted in a row on flange 12 above the individual pedal portions of foot pedal means 28, there being eight levers 79 in the present illustration. In the illustrated embodiment, each lever 79 is pivoted at 85 in a bracket 87 which is suitably mounted on the interior surface of the flange 12. A stop 88 is mounted on bracket 87 to limit the permitted counter clockwise movement of lever 79, as viewed in Figure ll.

The stationary sheaves or pulleys 8b are eight in number, one for each lever 79, and are rotatably mounted on a vertical shaft 89 which is supported by a bracket 91 on flange 12. The pulleys 39 are independently rotatable relative to each other and are located at the center of the instrument so that they may be operated in connection with the lever assemblies 26 for both body blocks 13 and 14.

Each cable 83 is connectedthrough a turnbuckle 92 to an associated lever 79 above the pivot 85, for example by a hook indicated. at 93. The cable 83 extends from the turnbuckle 92 around an associated sheave or pulley 8d and is connected to the frame of a corresponding. movable pulley 82. The associated flexible cableyoke 84 is provided at each end with a previously de scribed connecting loop portion 62 which fits into the notch 61 in a

lever

33 or 34. The central portion of the cable-yoke 84 rides inthe groove'o-f the rotating element of movable pulley -82.

, With the described construction of connector means 27, the loops 62-atthe ends of each cable-yoke 84 may be hooked over the-lower'ends of selected levers 33 and '34; Alternatively-both loops 62 of a single cable 84 be hooked over a

single'lever

33 or 34. Furthermoreft he' loops 62-for 'a-nuniber of cables 84 may be hooked over a single lever, so that such lever will pivot upon pressing of different ones of the foot pedal por tions of the foot pedal means. This results in great flexibility of operation, since by simply hooking the loops 62 over different levers the player or tuner may achieve awide variety of chord formations. Because of the central location of the stationary pulleys 80, the loops 62 on a single cable 34 may, if desired, be associated with the lever assemblies 26 of bot-h body blocks 13 and 14.

After the loops 62 for each cable 84 have been booked around the desired

levers

33 or 3 turnbuckle 92 is adjusted in such manner that there is no slack in the cables when lever 79 is pivoted against stop 88. This insures that upon actuation of the foot pedal means 28 there will immediately be movement of the associated

levers

33 or 34. Of course, turnbuckle 92 is not tightened sufficiently to pull the levers from the neutral post tions shown in Figure 5.

It is emphasized that the floating or movable pulleys 82 permit full movement of the associated

levers

33 or 34 until they engage their corresponding stop means 37 and 38. Thus, the actuated positions of the levers 33. and 34 are determined solely by the settings of the stop means 37 and 38, regardless of the

levers

33 or 34 with which the loops 62 are associated.

Construction of the foot pedal means 28 Referring particularly to Figures 1-3, the foot pedal means comprises a plurality of foot pedals 94 each of which is located directly beneath an associated lever 79. Each foot pedal is preferably channel shaped, as illustrated in Figure 2, and. is pivotedby a pin 96 to the ears or lugs 97 of a. bracket 93 which is mounted on a crossbar 99 at the front of the instrument; Cross bar 99 is secured by connector elements 191 (Figure l) to the lower ends of the front legs 11 of the instrument.

A slot 102 is formed in the upper or web portion of each foot pedal, being of suflicient size to receive a cylindrical sleeve 103 which is internally threaded to receive the lower threaded end of a pull rod 104. The upper end of each pull rod 104 is hooked at 106 for connection to the associated lever 79.

Mounted at the lower end of each sleeve 193 is a ball 1ti7 adaptedv to be inserted through around opening 108 at one end of the slot 192 of each pedal. The ball 107 is inserted through opening 108 during assembly of the instrument, and is then slid to the illustrated position (Figures 2 and 3) at which the ball prevents the sleeve 1193 from moving upwardly out of slot 102. This key arrangement greatly facilitates assembly of the instrument after it is taken out of its carrying cases. When in mounted condition, ball 107 is socketcd in a second ands'm'aller hole at the other end of slot 102 from opening 108.

An adjustable stop is provided on each foot pedal 94 and comprises a lug 109 (Figure 2) secured on the web of the pedal adjacent the upwardly extending base portion of bracket 98. A screw 111 is threaded horizon= tally through each lug 109 and is adapted to bear against the bracket base, there being a helical compression spring 112 provided around the screw between its head and the lug 109 to prevent shifting of the screw except when it is intentionally adjusted.

In adjusting the pedal means, each pedal 94' is first pivoted to the desired elevation, after which the stop screw 111 is adjusted so that it bears against the base of bracket 98 when the pedal is' at such desired elevation. It is to be understood that the pedal elevation for various pull rods 104 may be different, so that the operator may slide his feet from one pedal to another and comprehend, because'of theipedal elevation, which pedal is being depressed.

Ass'oon as each pedal 94 and sto'phas been adjusted, it is merely necessary to'rotate sleeve 103 until the-as;

sociated pull rod 104 is pulled tight, but not so tight that the corresponding lever 79 comes out of engagement with its stop 88. It follows that when the pedal 94 is depressed, there will immediately be rotation of the lever 79 and consequent operation of the

cables

83 and 84, and levers 33 and 34, without slack or play. The lowermost position of any pedal 94 is determined solely by the adjustment of the stop means 37 and 38 associated with the

levers

33 or 34 to which the corresponding cable 84 is connected.

Brief summary of operation The instrument is assembled, after being carried, by merely mounting the legs 11 onto the frame 10, connecting the cross bar 99 between the two front legs 11, hooking the hooks 106 through the levers 79 (Figure 2), inserting balls 107 in key slots 102108, and rotating the sleeves 103 to tighten the pull rods 104. It is not necessary to adjust the

cables

83 and 84, etc., each time the instrument is disassembled and reassembled, since the stops 88 operate to maintain the cables tight even when the pull rods '104 are not connected to levers 79.

When it is desired to change the chord pattern of the instrument, it is merely necessary to loosen the turnbuckles 92 (Figure 11) and then mount the loops 62 over the desired

levers

33 and 34. Turnbuckles 92 are then retightened, but not sufliciently tight to pull the outer edges of

levers

33 and 34 away from the right ends

of'the slots

53 and 54, as viewed in Figures 5 and 6.

The instrument is then played in the conventional manner, various ones of the foot pedals 94 being pressed when his desired to change chords. For example, and referringparticularly to Figure 11, let it be assumed that the illustrated pedal 94 is depressed. This operates the pull rod'104 to rotate bell crank lever 79 clockwise. The

cable 83 is then tensioned to rotate the illustrated sheave 80 and effect movement of the movable pulley 82 to the left. This causes movement of the illustrated cable-yoke 84 to the left with consequent clockwise movement of the

levers

33 and 34 to which the loops 62 on cable 84 are connected. This'movement continues until the inner edges of the

levers

33 and 34 engage the base portions of theloops 74 (Figure 6) 'of

adjustable stops

37 and 38. This movement is normally accompanied by a slight rotation of the rotating part of pulley 82, especially when the

adjustable stops

37 and 38 for the illustrated

levers

33 and 34 are not at the same settings.

Clockwise rotation of the lever 34 from the position shown in Figure 5 to that shown in Figure 7- causes operation thereof as a first class lever around the pivot 69. This, as described above in detail, effects tensioning of the associated string 17 to raise its pitch, it being understood that the lever 33 associated with the operated lever 34 does not then rotate and that pivot 69 remains fixed. Of course, the loops 62 for a particular cable 84 are not normally associated with

levers

33 and 34 of a single set, i.e. with levers connected by a rivet 69, this being because actuation of the levers of a single set at the same time would cause them to more or less neutralize each other.

Clockwise rotation of the lever 33 from the position shown in Figure 5 to that shown in Figure 8 causes the lever 33 to operate as a second class lever, as above described, which shifts the pivot 69 to the left. The knifeedge pivoting action as illustrated inFigure l0 and, as

previously described, results in shifting of the pivot from the solid line position to the phantom line position in Figure 10. Shifting of pivot 69 to the left causes the at edge 70.

The amount of rotation of the

levers

33 and 34 to which loops 62 are connected is determined solely by the settings of the adjustable stop means 37 and 38, which may be altered by rotating the screws 76 as de scribed above in detail.

Upon release of the foot pedal 94, all the parts return to their original positions, the levers 33 being rotated counterclockwise by springs 36, and the levers 34 being rotated counterclockwise by the tension of strings 17.

Various embodiments of the present invention, in addition to what has been illustrated and described in detail, may be employed without departing from the scope of the accompanying claims.

I claim:

1. In a tension-controlling means for a tensioned string of a musical-instrument of the lute type, a plate mounted on said instrument and having slot means formed therein, and a lever assembly having at least a portion extended through said slot means and connected with said string, said lever assembly having side regions disposed adjacent the walls of said slot means for guiding of at least said portion of said lever assembly during movement thereof in said slot means, said lever assembly having a notched fulcrum-engaging portion engaged with said plate at an end of said slot means.

2. In a tension-controlling means for a tensioned string of a musical instrument of the lute type, first and second plates fixedly mounted on said musical instrument in spaced relationship, said first and second plates having slots therein, a lever plate extended through said slots for guiding thereby, one end of said lever plate being connected with said string, and means associated with the other end of said lever plate for effecting movement'thereof, said lever plate having a fulcrum-engaging portion pivotally engaged with said plate at one end of said slot.

3. In a tension-controlling means for a string of a musical instrument of the lute type, a plate mounted on said instrument at one end of said string, said plate having slot means formed therein, first and second levers extended through said slot means and guided thereby, said levers being generally parallel to each other and transverse tosaid string, means to connect said second lever to said string on one side of said plate, pivot means to connect said first and second levers to each other at a point on the other side of said plate, a notch formed in said first lever for rocking on a fulcrum means adjacent said slot means, and means connected to said levers to effect selective rotation thereof and consequent lowering or raising of the tension on said string.

4. The invention as claimed in claim 3, in which said fulcrum means comprises a portion of said plate at one end of a slot therein, said slot forming a part of said slot means, and in which said notch in said first lever has edges disposed at more than a degree angle with relation to each other for rocking of the apex of said notch relative to said plate in a knife-edge action.

5. The invention as claimed in claim 3, in which said slot means comprises a single slot in said plate, in which said first and second levers at points adjacent said slot are in fiatwise engagement with each other, and in which the surfaces of said first and second levers remote from each other are in rubbing engagement with the walls of said slot.

6. In a string-tension controlling means for a string of a musical instrument of the lute type, first and second plates fixedly mounted on said musical instrument adjacent one end of said string, a slot provided in said first plate, slot means provided in said second plate generally parallel to said slot, first and second lever plates extended through said first plate slot and through said slot means insaid second plate, means to connect said second lever to said end of said string on oneside of said first plate remote from said second plate, means to pivotally connect said first lever to said second lever on the other side of fag-9783882 l1 said firstplate relatively adjacent said second plate, notch means provided in said first lever to efi'ect'rocking thereof on said first plate at one end of said slot therein, and actuating means to effect rotation of said levers-and'c'onsequent change in the tension on said string.

7. The invention as claimed in claim 6, in which said second plate is provided with fixed stop means adapted to be "engaged by said levers, said second lever being maintained against said fixed stop means by the tension of said string except during operation of said actuating means, and in which means are provided to resiliently maintain said first lever in engagement with 'said fixed stop means except during operation of said actuating means.

8, The invention as claimed in claim 6, in which adjustable stop means are associated with said levers to limit the amount of rotation thereof by said actuating means.

9. A tension-controlli-ng lever assembly for a string of a musicalinstrumentof the lute type, said string extending under tension over a bridge at the tail portion of the instrument, which-lever assembly comprises first and second generally parallel metal plates mounted in spaced relationship on said musical instrument at said tail portion thereof, said plates being generally parallel to said-string, a slot formed in said first plate generally parallel to said string, slot means formed in said second plate generally parallel to said string and in a location corresponding generally to the location of said slot' in said first plate,

first and second metal lever plates extending parallel to each other and. transversely of said string through said slot and said slot means, said levers being in fiatwise engagement with each other in the region of said slot in 'said first plate, notch means formed in said first lever for engagement with said first plate at the end of said slot therein relatively adjacent said bridge for effecting rocking of said first lever on said first plate at said slot end, means to connect said second lever to the end of said string at a point spaced from said first plate on one side thereof remote from said second plate, pivot means connected to said first and second levers to pivotally connect said first lever to said second lever at a point disposed between said first and second plates and relativelyadjacent said first plate, said second lever being shaped to prevent interfering engagement thereof with'the end of said slot in said first plate, spring means connected to said first lever on the side of said second plate remote from said first plate to pivot said first lever against a portion of said second plate relatively remote from said bridge, the corresponding portionof 'said second lever being maintained in stopping engagement with said second plate due to the tension of said string, means to engage the end of said second lever remote from said string to effect pivoting of said second lever about said pivot means in a given direction effecting te'nsioning ofsaid string in a first class lever action, and means to engage said first lever remote from said notch means to pivot the same about said end of said first plate slot in said given direction in a second class lever action, said second'class lever action operating to efiect pivoting ofsaid second lever in a direction opposite to said given direction in a third class lever action to effect lessening of the tension on said string.

10. The invention as claimed in claim 9, in which a loop is mounted around each of said levers, and adjustmerit elements are connected to each of said loops to vary the position thereof, said loops being adapted to be engaged by said levers upon pivoting thereof 'to thereby determine the degree of tensioning or relaxation of said string.

ll. The invention as claimed in claim 9, in which said 7 means to pivot said levers includes cable means, andfoot pedal-operated means connected to said cable means.

12. A guitar, which comprises an elongated body a plurality'ofstrings stretched oversaid body in parallel I2 I relationship, a plurality of levers mounted on said body adjacent the ends of said strings and operatively associated therewith, pedal means adapted to be operated by the feet of the player ofthe instrument, and connector means to associate said foot pedal means with said levers, said connector means comprising a plurality of stationary sheaves mounted on said body at the end thereof remote from said levers, a cable mounted around each sheave and having one end thereof associated with a selected foot pedal portion of said foot pedal means, a movable pulley having its frame or yoke mounted at the other end of each cable, and a flexible cable yoke mounted around the rotatable portion of each movable pulley, said cable yokes each having removable connector elements on each end thereof, said connector elements being adapted to be associated in a readily removable manner with selected ones of said levers.

13. The invention as claimed in claim 12, in which said levers are each provided with a notch in the lower end thereof, andin which said connector elements on said cable yokes comprise loops adapted to fit in said notches.

14. A guitar, which comprises an elongated horizontal body, leg means to mount said body, a plurality of strings mounted in parallel relationship and in a horizontal plane over said body, upperand lower metal plates fixedly mounted on said body in vertically spaced parallel relationship at one end of said body, said plates being formed with slots extending longitudinally of said strings, a set of lever plates provided in said slots for each of said strings, pivot means disposed between said plates for pivotally connecting to each other the lever plates for each string, means to pivot one lever for each string to said upper plate at the inner end of the slot therein, means fio connect theother lever for each string to said string and at a point spaced above said upper plate, resilient "means to pivotsaid'onellever to a neutral position except during actuation thereof, said other lever being held in neutral position by the tension of its associated string, .a'plu'rality'"of'flexible cableyokes adapted at their ends to removably connect to the lower ends of levers assocL 'ate'dI-with different strings of said guitar, the central portion'of 'each'cableyoke being mounted around the rotating componentjof'a movable pulley, a plurality of cables connected to the fixed components of said movable pulleys, stationary sheave means mounted at the end of said body remote from said levers and adapted to receive said last-named cables,'a plurality of bell crank levers mounted on said body at horizontally spaced positionsand connected to said last-named cables, pull rods connected to said bell cra'nl; levers and extending downwardly, and ,foot pedals connected to said pull rods.

1-5. A portable pedaliguitar, which comprises an elongated rigid horizontal body, a plurality of parallel strings dlsposed over said body and connected thereto at one end thereof, a plurality of legs removably secured to said body, across bar connected horizontally between two of said legs in spaced relation from said body, a plurality of pedals pivotally mounted on said cross bar, a first set of levers pivotally mounted on said body one above each of said pedals, a plurality of connectors respectively connecting said pedals to said levers in said first set to result in pivoting of said levers in response to depressing of said pedals, said connectors being removable from said levers, a secondset of levers pivotally mounted on said body at the other end thereof and respectively connected to said strings, a plurality'of cables respectively connected between said levers in said second set and said levers in said first set, a plurality of stops provided on said body to limit the pivotal movement ofsaid levers in said first set-in response to pulling'thereon by said cables, and means to vary the tension on each of said cables to cause the same to be taut when the associated lever in said first set is eng aged with said stop therefor.

16. The invention as claimed in claim 1, in which said lever assembly comprises first and second levers, and in which means are provided to pivotally connect said first and second levers to each other.

17. The invention as claimed in claim 16, in which each of said levers comprises a plate-like member, and in which side surface portions of said plate-like members are engaged with each other in the vicinity of said pivotalconnector means.

18. The invention as claimed in claim 1, in which foot-operated actuator means are connected to said lever assembly for pivoting of at least a portion thereof to effect variation in the tension of said string.

19. The invention as claimed in claim 1, in which a second plate is mounted on said instrument in spaced relationship relative to said first-mentioned plate, said second plate having a slot therein, and in which at least a portion of said lever assembly extends through said slot in said second plate for guiding thereby.

20. The invention as claimed in claim 1, in which said lever assembly comprises first and second levers, in which said first lever extends through said slot means and is connected to said string on one side of said plate, in which means are provided to pivotally connect said levers to each other on the other side of said plate, in which said notched fulcrum-engaging portion is formed in said second lever, and in which actuating means are connected to said levers for selective rotationthereof to vary the pitch of said string selectively in opposite directions.

21. The invention as claimed in claim 20, in which said slot means is a single slot having parallel walls, in which said first and second levers comprise plate-like stampings having portions in fiatwise engagement with each other in the vicinity of said pivotal-connector means, and in which said engaged portions of said stampings are disposed in said slot and have outer surfaces in rubbing engagement with said walls for guiding thereby.

22. The invention as claimed in claim 20, in which a second plate is mounted on said instrument in spaced and generally parallel relationship relative to said first-mentioned plate and on said other side thereof, said second plate also having slot means therein parallel to said slot means in said first-mentioned plate, and in which portions of said levers extend through said slot means in said second plate.

23. The invention as claimed in claim 22, in which spring means are provided to bias said second lever to a predetermined position against an end of said slot means in said second plate, said predetermined position corresponding to a predetermined position against an end of said slot means on said second plate assumed by said first lever due to the tension of said string, and in which adjustable stop means are associated with each of said levers to limit the degree of pivoting thereof away from said predetermined positions due to operation of said actuating means.

24. The invention as claimed in claim 1, in which a lever assembly is provided for each of a plurality of strings of said instrument, each of said lever assemblies including first and second levers, in which pedal means are provided on said instrument and adapted to be operated by the feet of the player, in which a plurality of stationary sheaves are mounted on said instrument remote from said levers, in which a cable is mounted around each sheave and has one end associated with a selected foot pedal portion of said pedal means, in which a movable pulley is provided with its frame or yoke mounted at the other end of each cable, in which a flexible cable yoke is mounted around the rotatable portion of each movable pulley, and in which said cable yokes each have connector elements at each end thereof and adapted to be associated in a readily removable manner with selected ones of said levers.

25. The invention as claimed in claim 24, in which said levers each have notches at the ends thereof remote from the strings, and in which said connector elements on said cable yokes comprise loops adapted to fit into said notches.

References Cited in the file of this patent UNITED STATES PATENTS 1,259,062 Wilber Mar. 12, 1918 2,458,263 Harlin Jan. 4, 1949 2,467,086 Hise et al. Apr. 12, 1949 2,519,044 Hise Aug. 15, 1950 2,531,569 Hise et al. Nov. 28, 1950 2,573,963 Gaut Nov. 6, 1951 2,610,536 Cousineau Sept. 16, 1952 2,662,439 Snodgrass Dec. 15, 1953 2,828,660 Paulsen Apr. 1, 1958