GB2349010A - Variable capo tasto - Google Patents

Abstract

A capo tasto or head stop suitable for any stringed instrument is capable of holding notes or chord shapes independent of the player, said note selection being set beforehand by the player for a given piece of music. A bar 1 is held firmly across the neck of the instrument by a collar around the rear of the instrument neck. The bar is positioned by means of two flexible jaws 7 that allow for placement at different positions along the instrument neck. By the provision of a lug or step 8 positioned on each flexible jaw, the bar is maintained clear of the fingerboard to prevent contact between bar and strings. The bar is furnished with arms 4 fitted with pressure pads 5 that can move laterally through the bar to both left and right thus depressing strings across a plurality of semitones, thus making it possible to hold down individual strings across a range of note or fret positions whilst still allowing the musician access to all other possible finger positions on the fingerboard. The present invention is not limited to a fretted instrument, nor is it limited to operating across one fret alone, but is capable of spanning several frets, or intervals in the case of fretless instruments. It is also capable of attachment to stringed instruments fitted with pairs of strings such as twelve-string guitar or mandolin. The invention can be applied to instrument necks of differing shapes and sizes, from e.g. a mandolin to a double bass.

Description

VARIABLE CAPO TASTO This invention relates to a capo tasto suitable for any stringed instrument and capable of holding individual notes or chord shapes independent of the ployer.

There have been many applications that have attempted to widen the scope of music played by various stringed instruments ranging from alternative bridge and heod stock designs to slidoble chord forming machines and selective capo tastos. However, none have proved commercially practicable. In Collins et al. US 4926732 there is proposed a similor device that depends on a bulky mechanical arrangement of levers and cams to select certain strings across a given fret while in US 4195546 spring members are mounted on the head stock Others are limited to fretted instruments or operate only across one fret The present invention is highly compact and is not limited to a fretted instrument, nor is it limited to operating across one fret alone, but is capable of spanning several frets, or note intervals in the case of frettess instruments. It is also capable of attachment to stringed instruments fitted with pairs of strings such as twelvestring guitar or mandolin. The basic concept of this invention is capable of application to instrument necks of differing shapes and sizes, from e. g. a mandolin to a double bass, within a range of different embodiments.

According to the present invention there is provided a bar which is held across the strings of a guitar or other related instrument in a raised position clear of said strings by means of supports or jaws at each end and tensioned by means of a restraining mechanism holding the device to the rear of the neck of the instrument The bar is maintained in place by means of said flexible jaws, the flexibility being either inherent in the material or by means of a sprung connection between said bar and said jaws. Said jaws are flexible in order to allow said bar to be placed at different positions wherever required along the neck of the instrument, which in practice is generally tapered. By the provision of a lug or step positioned on the proximal side of each flexible jaw, the bar is maintained at a required distance clear of the fingerboard in order to prevent contact between the strings and said bar. Said bar is fumished with a plurality of extension arms shaped to press down upon the strings and fitted with pressure pads, capable of moving laterally through the bar to both left and right thus giving the ability to depress strings at both higher and lower frequencies than those at the selected capo position, making it possible for the player mechanically to hold down individual strings across a range of note or fret positions whilst still allowing access to all other possible finger positions on the flngerboard. Said arms may be shaped with any given section but a preferred form is substantially round with a flattened arc of said circle formed at the top in order to co-operate with locking means provided on top of said bar. The proposed capo will be able to span four or more semitones allowing complete flexibility of tuning, and can be provided with extension arms of differing lengths to achieve this end with the minimum of interference to the ployer. This would provide a"universal"means of forming the required chord shape, open tuning or individual notes. Said means of locking said arms into the desired position relative to said bar may be achieved in a variety of ways, e. g. screw threaded pins pressing from the top of the bar upon the arms, lever operated cams bearing down in similor fashion or even a simple interference fit between said arms and said bar. Since said extension arrns are intended to be removable and may be inserted from either side of said bar it will be suitable for rightand left-handed users Said extension arms may be formed integrolly with said bar or some portion thereof being a moulded or shaped item to form a fixed chord shape or open tuning.

However the device is fashioned, each said extension arm will require to press down upon its related string and will be shaped so to do whether by means of a right angle bend or a downward sloping orientation or, in a preferred embodiment, by means of two substantially right angled bends or a semicircular bend together with a short retum portion such that when the extension arm is retracted it will press directly below said bar and not to the side thereof. In any case it will be desirable to provide a flexible terminal or pressure pad at the string contacting end of each extension arm in order to prevent wear upon the strings and to widen the area depressed. In order to operate in conjunction with a twelve-string guitar or similarly tuned instrument each extension arm would be provided with a pressure pad or foot of sufficient width to depress two strings.

In practice, certain in-line chord shapes require additional pressure on the side of the bar away from the selected pressure points in order fully to depress said points and maintain the chord without distortion. Any such support can not impinge upon open strings without altering the chord structure. To facilitate this, said ajustable extension arms may be equipped with a hinge avowing each arm to operate laterally across the fingerboard to depress an adjacent string rather than that directly below the hole in which it is placed. This facility will prove useful in cases where additional pressure is required on the side of the bar away from the selected note positions to balance the device. Altematively, it may be desirable to utilise one of the longer arms provided so that it projects outward from the bar on the distal side, away from the body of the instrument Onto said projecting extension arm may be attached an additional pressure pad of special design which can be slid onto said arm, having a hole therein of corresponding section to that of said arm and being of sufficient height to match the height of the said arm above the string.

The bar is thus suspended clear of the strings and the individua) strings or pairs of strings are held down by means of extensible arms set at the required distance from the bar either higher or lower along the neck, thus allowing a wide variety of notes and chords to be held as a basis for the ployer's own fingering. Optionally, an insert made of some resilient material may be attached to the underside or the rear of the bar to fbnn a barre as in the case of a normal capo tasto with or without the selection of note or chord positions on the neck above the capo, that is, the side nearest the body.

The whole is held firmly against the face of the instrument neck by means of a flexible strap or mechanical latch or combination of both surrounding and bearing forcibly upon the rear of the neck so that the steps or lugs attached to the flexible jaws are clamped to the edges of the fingerboard with the bar forming a transverse bridge across the neck of the instrument In practice it has been found desirable to incorporate a block or pad of material on the inside of said strap or latch to intervene between said strap and the rear of the instrument neck in order to increase the tension applied thereby. Said jaws perform three essential functions ; namely maintaining the bar at the correct height, keeping said bar centrally in position across the neck and by means of their flexibility to allow for the differing width of the neck at different positions along said neck In the following drawings it is not intended to exclude features from another Figure from each specific embodiment but rather to provide a basis for their combination in specific applications.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows the essential features of the invention and the optional provision of a hinge upon an arm.

Figure 2 shows an altemative embodiment of the invention featuring optional details.

Figure 3 shows the invention with the addition of an insert to form a barre.

Figure 4 shows such an insert with integral arms for forming chords.

Figure 5 shows a variation of the invention utilising a pre-formed chord shape that may be rapidly attached and detached from the bar thus allowing instant re tuning.

Figure 6 shows a preferred embodiment suitable for production.

Figure 7 shows an embodiment of the invention equipped with cams for locking the extension arms in the desired position.

Referring to the drawings, Figure 1 shows the bar 1 formed of rigid material provided with a plurality of slots or holes horizontally 2 and vertically 3, the former in order to accommodate rigid adjustable extension arms 4 terminating in resilient pressure pads 5 while the latter are each threaded to co-operate with a locking device 6 being in its simplest form a screw threaded pin fitted into a correspondingly threaded hole 3 and fumished with means of turning by hand or by means of a screwdriver or other tool. At the furthest extremities of said bar 1 flexible jaws or supports 7 are attached in order to locate said bar 1 centrally across the neck of the instrument while at the some time supporting it above the strings of said instrument by the use of balance points 8 in the form of steps or lugs formed on the inward facing sides of said jaws 7 which bear on the edges of the neck of the instrument By forming said jaws 7 with a mounting hole eccentrically displaced on the axis between the inward and outward faces of said jaws 7 and forming said balance points 8 also upon said outward face it is possible to rotate said jaws 7 as necessary to accommodate differing widths of neck Said jaws 7 may be formed either of flexible material as shown or rigid material that is flexibly attached to said bar 1 by means of e. g. a spring or springs that bias said jaws 7 towards each other as shown in Figure 6 in order further to accommodate the widening of said neck towards the instrument body. Said balance points 8 may be faced with resilient material to prevent wear on the instrument and may equally be in the form of an inward projection from said jaws 7 of any form. The whole is attached to the neck by means of a restraining strap hereinafter referred to as the collar 9 being in its simplest form mode of elostic or resilient moteriol and fumished with a plurality of locating holes 10 which locate over pins or studs 11 provided at either end of said bar 1 when said collar 9 is stretched around said neck and placed under tension. Alternative means of holding jaws 7 and bar 1 in place upon the instrument neck or of tightening said restraining strap or collar 9 might equally be used separately or in combination, such devices being well known. In one desired embodiment the jaws 7 are spring biosed together to clamp the device upon the instrument neck before being bghtiy attached by means of a collar 9 or other form of restraint In the desired embodiment said collar 9 attaches to the lower portion of said jaw 7 as shown in Figure 6.

In proctice the ajustable extension arms 4 hereinafter referred to as arms 4 will be ranged to either side of said bar 1 to form the desired chord or selection of notes and locked in place by means of locking pins 6 prior to being attached to said instrument neck with balance points 8 formed on flexible jaws 7 bearing upon the edges of said neck and being compressed thereto by means of the collar 9 attached to said bar 1 by means of holes 10 formed upon said collar 9 being elastically located over the projections hereinafter referred to as studs 11 formed on the extreme ends of the bar 1 as shown or upon the jaws 7. If desired said jaws 7 may be rigid but inwardly biased by means of a spring or other tensioning means, collar 9 being attached to said jaws 7 by means of holes 10 in the collar 9 locating over studs 11 formed at some point on the jaws 7, alternative means of attaching said bar 1 and jaws 7 not being hereby excluded.

Atthough the capo will be fumished with a set of arms 4 suitable in number to the instrument for which it is designed, e. g. six for a guitar, not all will be required at a given time. Said arms 4 are shown rectangular but may be fumished with any form of cross-section although it has proved practicable to form them with a substantially round section having an arc flattened to co-operate with its related locking pin 6 for ease of location. In the case of a dual-stringed instrument e. g. a twelve-string guitar, one arm 4 is provided for each pair of strings, having a laterally extended pressure pad 5 at its tip capable of depressing two adjacent strings at the same time. The length of arms 4 provided may vary according to the specific application. Also illustrated here is the provision of a hinge 21 embodied within a given arm 4 and operating laterally thus enabling said arm to bear upon an adjacent string rather than that directly beneath its location upon the bar 1 in order to balance the capo if required. This improvement also may be of use in forming chords generally in cases where its angular action makes the device more compact Said pressure pads 5 are generally made of resilient material having a flattened tip forming a cap on the end of said arms 4 although other means such as adhering a pad of said resilient material to a flattened section formed at the extremity of said arm 4 are not hereby excluded. However said resilient material is not an essential feature of the invention but in practice will decrease wear upon the instrument to which it is attached.

Said arms 4 may take any shape as herein described above in order effecfively to depress related strings although a preferred embodiment terminates at one extremity in a substonbally semicircular bend and a small retum portion provided with a foot or pressure pad 5 at its extremity in order that when fully retracted said arm may depress said string vertically below said bar 1 rather than to the side thereof. As described above said arms 4 are herein held in place by means of helically threaded locking pins 6 which may be formed with a substantially flat section at their top end forming a key, or have a knurled or similor surface to provide a grip upon its circumference for manual operation. Said locking pin 6 may otherwise be formed with means operable by a particular tool e. g. a spanner, Allen key, Phillips screwdriver or similor. Alternative means of retaining said arms 4 in place such as an interference fit as shown in Fig. 2 are not excluded. Alternative means of holding the capo on to the neck of the instrument as aforementioned may equally be employed.

Figure 2 shows an altemative configuration wherein the ends of the arms 4 are not bent at an acute angle but are fumished with a pressure pad 5 provided with a suitably sized hole into which the end of said arm 4 is slotted thus forming a right angled configuration in order efficiently to depress a string. Furthermore, the balance points 8 are characterised not by lugs as in Figure 1 but as steps formed in the flexible jaws 7 while the collar 9 is depicted as being rigidly attached at one end of the bar 1 and alternative means of tensioning said collar 9 are illustrated in the form of a lug 12 and buckle 13 provided at one end of said bar 1. Said buckle 13 is formed with an interlocking pin 14 to co-operate with said lug 12 for rapid attachment of the capo and a tensioning device wherein the material of said collar 9 is tightly wrapped over on itself and the whole is tightened by the use of an'over-centre'tensioner 15 much in the fashion of a metal watch bracelet although any known means of attachment capable of providing adequate tension may be utilise. Locking pins 6 have been omitted in favour of alternative means in the form of an interference fit between said arms 4 and said bar 1 whether achieved by the insertion of collars 16 within said holes 2 or by means of suitable material forming said bar 1 such that in either case arms 4 may be pulled or pushed into place through holes 2, said arms 4 being tightly maintained in place by the friction generated between said arms 4 and said collars 16 or bar 1. By the use of extension arms 4 shaped as shown in Figure 6 said bar 1 is effectively self-balancing at balance points 8 in most instances. However, the use of a long arm 4 fitted with a removable pressure pad 17 as a means of balancing the capo as hereinbefore mentioned is also shown. In this case a longer arm 4 than is required to hold the specific note is utilise thus allowing a projection on the distal side of bar 1 which when fitted with said pressure pad 17 wil) balance the pivoting action at balance points 8.

Figure 3 shows the bar 1, jaws 7 and balance points 8 as provided with an additional insert 18 of resilient material that is shaped to clip around said bar 1 in the space formed between the underside of the bar 1 and the inner faces of the jaws 7, its lower face roughly at a level with the balance points 8 in order to provide the addition) potential of barring all the strings with or without the use of arms 4 to depress specific strings at higher frequencies. A further variation in the design may be produced by adapting the basic moulding of said insert 18 and extending it laterally to form arms 4 capable of depressing strings higher up the instrument neck in set chord positions while balancing the device around the axis of the balance points 8. In this form said insert 18 may be fashioned more shallowly so as to avoid the strings thus allowing its related arms 4 to depress strings upon the instrument neck both above and below said bar 1.

Figure 4 shows insert 18 equipped with integrally moulded arms 4 as mentioned in Figure 3, as an alternative means of depressing the strings of the instrument In other respects it functions just as in Figure 3 and may or may not be in linear contact with the strings, being mode in a variety of forms for different chords.

Figure 5 shows an embodiment in which the bar 1 is reduced in depth in order to form a chassis upon which an attachment may be removably mounted. Said attachment is a unitary moulded item into which are incorporated arms 4 and bearer 22 such that a musician wishing rapidly to change tuning may remove an attachment forming one chord shape and replace it with another. A variety of known means may be employed to hold said bearer 22 in place upon said bar 1 such as a central key 19 and slot 20 formed upon the bearer 22 and bar 1 respectively, or by means of lugs 24 on one member which co-operate with locating grooves 23 or undercut 25 formed on the other member, e. g. lugs 24 at the extremities of bearer 22 engaging within grooves 23 or undercut 25 formed on bar 1 on the inside faces of its extremities.

Figure 6 shows a preferred embodiment in which a circular bar 1 is formed with hollow cylindrical projections 26 at its extremities and provided with circular holes both vertically 3 and horizontally 2 for the securing of arms 4 as before described using threaded locking pins 6 fumished with knurled heads 27. Said horizontal holes 2 may in this case be formed within said bar 1 in non-liner fashion to allow for the curvature of the instrument's fin er board. Arms 4 as previously described of circular section with a flattened arc to co-operate with locking pins 6 are provided while end pieces 28 of cylindrical section with integral legs 29 bearing jaws 7 are slidably attached to said cylindrical projections 26 upon said bar 1 by means of screws 30 and tensioned by springs 31 housed within said end pieces 28 to provide flexibility of attachment to the instrument as before described. Said screws 30 locate within the threaded hollow core of said cyindricol projections 26 while said springs 31 are housed within a relatively larger intemal section of said end pieces 28 and said cylindrical projections 26 are housed within a relatively narrower intemal section of said end pieces 28 of corresponding diometer. In order to prevent rotation one or more arcs of said cylindrical projections 26 are flattened to co-operate with a similarly flattened section within the relatively narrower portion of said end pieces 28. Said legs 29 project beyond the lowest part of said jaws 7 to form studs 11 for the attachment of a collar 9 bearing a pad 37 to provide additional tension as previously described. Said jaws 7 may be mounted eccentrically on said legs 29 as hereinbefore mentioned in order to accommodate differing widths of instrument neck Figure 7 shows an alternative embodiment wherein the capo is substantially as Figure 6 but with differing detail upon the bar 1 in order to provide an altemative means of holding arms 4 in place upon the bar 1 by means of levers 32 equipped with cams 33. Slots 34 are formed downwards within said bar 1 and means for the pivoting action of said levers 32 is provided e. g. a longitudinal hole 35 bored between the extremities of said bar and fitted with a pin 36 of corresponding diameter and length.

Said levers 32 may be of any appropriate shape notwithstanding that said cams 33 must both depress said arms 4 and lock said levers 32 in the closed position when said levers 32 are operated.

Claims (12)

1. An apparats for depressing strings thereby holding notes on a stringed musical instrument of conventionol layout with or without frets across a plurality of frets or semitones ; comprising a bar held above the strings by means of flexible supports at its extremities which attach to the sides of the instrument neck and bearing a plurality of string stopping means, said plurality of string stopping means being laterolly displayed to engage said strings at any required combination of notes or fret positions, together with means for releasably mounting said bar to the neck of a stringed musical instrument

2. A capo as claimed in Claim 1 wherein said flexible supports are composed of rigid supports which are biased inwardly by means of springs.

3. A capo as claimed in Claim 1 and 2 with string stopping means in the form of arms of ajustable length.

4. A capo as claimed in Claims 1 to 3 which features locking means in the form of screwed pins fumished with heads shaped for ease of tightening.

5. A capo as claimed in Claims 1 to 3 which features locking means in the form of cams formed upon operating levers pivotably mounted upon the bar.

6. A capo as claimed in Claims 1 and 2 where the string stopping means are in the form of a releasably attached unitary moulding set for a given chord structure.

7. A capo as claimed in any preceding Claim where the device is attached by means of a strap attached to the extremities of the bar or supports thereto.

8. A capo as claimed in any preceding Claim where the device is attached by means of a strap fumished with a pad forming a distance piece at the rear of the instrument neck to increase the effective pressure upon said capo.

9. A capo as claimed in any preceding Claim where the bar is attached by a strap releasably attached to one end thereof by means of a lug and buckle as herein described.

10. A capo as claimed in any preceding Claim wherein the arms are mounted upon the bar in non-liner fashion to correspond with the curvoture of the instrument neck

11. A capo as claimed in any preceding Claim wherein an insert is attached between the bar and the strings in order to form a barre.

12. A capo as claimed in any preceding Claim wherein the supports for the bar are arrange to increase the span of said supports when they are rotated.

13 A capo substantially as herein described with reference to Figures 1-7 of the accompanying drawings.

12. A capo as claimed in any preceding Claim wherein the supports for the bar are arrange to increase the span of said supports when they are rotated.

13 A capo substantially as herein described with reference to Figures 1-7 of the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS

1. A capo for depressing strings thereby holding notes on a stringed musical instrument of conventional layout with or without frets across a plurality of frets or semitones ; comprising a bar held above the strings by means of flexible supports at its extremities which'attach directly to the sides of the instrument neck and bearing a plurality of string stopping means, said plurality of string stopping means being laterally extended to engage said strings at any required combination of notes or fret positions, together with means for releasably mounting said bar to the neck of a stringed musical instrument 2. A capo as claimed in Claim 1 wherein said flexible supports are composed of rigid supports which are biased inwardly by means of springs.

3. A capo as claimed in Claim 1 and 2 with string stopping means in the form of arms of ajustable length.

4. A capo as claimed in Claims 1 to 3 which features locking means in the form of screwed pins furnished with heads shaped for ease of tightening.

5. A capo as claimed in Claims 1 to 3 which features locking means in the form of cams formed upon operating levers pivotably mounted upon the bar.

6. A capo as claimed in Claims 1 and 2 where the string stopping means are in the form of a releasably attached unitary moulding set for a given chord structure.

7. A capo as claimed in any preceding Claim where the device is attached by means of a strap attached to the extremities of the bar or supports thereto.

8. A capo as claimed in any preceding Claim where the device is attached by means of a strap fumished with a pad forming a distance piece at the rear of the instrument neck to increase the effective pressure upon said capo.

9. A capo as claimed in any preceding Claim where the bar is attached by a strap releasably attached to one end thereof by means of a lug and buckle as herein described.

10. A capo as claimed in any preceding Claim wherein the arms are mounted upon the bar in non-liner fashion to correspond with the curvature of the instrument neck

11. A capo as claimed in any preceding Claim wherein an insert is attached between the bar and the strings in order to form a barre.