WO2016111627A1

WO2016111627A1 - Clamping device for a string instrument

Info

Publication number: WO2016111627A1
Application number: PCT/NL2016/050015
Authority: WO
Inventors: Wilhelm Jasper Hagedoorn; Daniël Maarten TER BRAAK; Jacobus Antonius Franciscus Gramser
Original assignee: Gbo Design B.V.
Priority date: 2015-01-09
Filing date: 2016-01-08
Publication date: 2016-07-14
Also published as: NL2014101A; NL2014101B1

Abstract

Clamping device A clamping device for a string instrument, usually referred to as capo d'astro or simply capo, comprises a clamping body (20) and a tensioning device with a tensioning body (36,38) which is connected via a bracket (10) to the clamping body. The tensioning body is convertible between a tensioning position and a release position with an operating member (31, 32) of a locking assembly (30). The operating member is tiltable here about a tilting shaft (33) oriented substantially transversely of the neck of the instrument and the locking assembly (30) is located substantially medially on the bracket (10) on the back of the neck.

Description

Clamping device for a string instrument

The present invention relates to a clamping device for a string instrument comprising a clamping body intended and configured to lie clampingly against a strung neck of the instrument while exerting a clamping tension and comprising a tensioning device with a tensioning body which is connected via a bracket to the clamping body and is intended and configured to lie against the neck on a back thereof remote from the clamping body, wherein the tensioning body is convertible between a tensioning position, in which the neck undergoes the clamping tension between the tensioning body and the clamping body, and a release position in which the clamping tension is released.

Such a clamping device finds widespread application in string instruments with strings running over an elongate neck provided with frets. These are narrow, usually metal bars over a full width of the neck located at regular distances from each other and protruding above a fingerboard of the neck. On a guitar the frets therefore lie for instance a semitone from each other. By clamping a string on the fret it is possible to accurately strike a semitone higher, wherein the position where the string is clamped beyond the associated fret is no longer critical because the resulting string length is set by the position of the fret. A clamping device of the type described in the preamble can advantageously be employed with such a string instrument to raise the minimum pitch of the instrument, and is usually referred to as barre clamp, capo d'astro, capotasto or simply capo. A capo is a clamp used in string instruments with frets to make all strings sound a number of semitones higher. Depending on the construction of the capo and the instrument, this may mean a quint or more higher. This has the great advantage that the fingering remains unchanged when a key which is awkward for the instrument is required.

In order to achieve this the capo is arranged round the neck of the string instrument such that the clamping body touches the strings. Using a clamping mechanism a clamping tension is subsequently applied with which all strings are clamped collectively on the preceding fret in order to raise the basic pitch of the instrument accordingly. The clamping mechanism is formed in a known capo by a clamping strip with a tensioning member with which the capo is tensioned round the neck of the instrument. An alternative existing capo comprises a resilient clamp which is arranged round the neck and which carries the clamping body on the strung fingerboard side of the neck and supports resiliently with another leg on the back of the neck. The bracket is tightened by the spring tension, whereby the clamping body will act clampingly on the set of strings. A drawback or both these known clamping devices is that the clamping force is not very well defined and will depend partly on the local cross-section of the neck, which can vary along the length thereof. Known capos which have this drawback to at least lesser extent comprise a locking assembly and are tightened therewith so as to thus apply a better defined clamping tension. In these known capos the locking assembly lies laterally of the capo outside the neck. An operating member thereof is manipulated in the peripheral direction of the neck, i.e. tilted about a tilting shaft oriented roughly in the axial direction of the neck.

A drawback of these known clamping devices is that a certain de-tuning of the strings is found to occur in practice after the clamping device has been arranged in the prescribed manner, which de-tuning can moreover be of differing extent for the individual strings. The clamping mechanism, and particularly the lock applied therein, is moreover perceived as irksome by musicians because it can get in the way of placing of the thumb on the neck. The present invention has for its object, among others, to provide an improved clamping device which does not have one or more of these drawbacks, or at least does so to considerably lesser extent.

In order to achieve the stated object a clamping device of the type described in the preamble has the feature according to the invention that the tensioning body is convertible by means of a manually controllable locking assembly with an operating member which is tiltable about a tilting shaft oriented substantially transversely of the neck of the instrument between at least a first position, in which there is direct or indirect engagement thereby on the tensioning body in order to urge the tensioning body into the tensioning position, and a second position whereby the tensioning body is brought into the release position, wherein the locking assembly and the first tilting shaft are provided substantially medially on the bracket on the back of the neck.

In the clamping device the clamping force is thus applied by tilting the operating member of the locking assembly at least substantially medially under the neck, particularly about an axis oriented transversely of the neck. The clamping body thus clamps at least substantially uniformly on all strings and exerts a clamping force here on the strings which is particularly oriented almost solely in a direction perpendicularly of the fingerboard. This is a significant difference from the existing clamping devices which are tightened as it were round the neck in the peripheral direction, whereby the strings will also be subject to a shear force to an extent which varies and is not well controlled. The invention is based on the insight that the above-mentioned de-tuning can sometimes occur probably as a result of this latter. The locking assembly is moreover placed about medially on the back according to the invention and so is readily accessible to the musician without impeding his/her thumb placing.

The tensioning body can be urged per se into the tightened second position in diverse ways, for instance by a translation thereof under force. An exceptionally compact and

operationally reliable embodiment of the clamping device is however characterized according to the invention in that the tensioning body comprises a tilting body tiltable about a second tilting shaft oriented substantially transversely of the neck of the instrument, which second tilting shaft extends substantially parallel to the first tilting shaft from the bracket. An accurately defined tilting movement of the operating member is transmitted here onto a likewise accurately defined tilting movement of the tensioning body, this finally resulting in an accurately defined clamping force of the clamping body on the strings. For a balanced distribution of the total clamping force of the clamping body over the strings despite the fact that these can be of individually differing cross-section, a particular embodiment of the clamping device according to the invention has the feature that the clamping body is intended and configured to enter with a contact side into contact with the strung neck and comprises a compressible top layer on the contact side. Because of the compressible top layer the clamping body is thus able to conform to the individual thickness of a string, so that at least substantially the same pressure is applied thereto as to the further strings of the instrument. In order to prevent damage to the neck of the instrument as a result of being clamped in the clamping device, a further particular embodiment of the clamping device according to the invention has the feature that the tensioning body is intended and configured to enter with a contact side into contact with the back of the neck and comprises a compressible top layer on the contact side. The tensioning body thus rests with a relatively soft compressible top layer on the back of the neck, whereby the tensioning force is optimally distributed and transmitted thereover, and damage to the neck is also prevented.

An exceptionally practical particular embodiment of the clamping device is characterized according to the invention in that the clamping body, the bracket, the tensioning body and the operating member are manufactured at least substantially from an at least substantially form-retaining material, in particular a metal or a plastic, and that the top layer of respectively the clamping body and the tensioning body covers a shoe of an optionally natural elastomer provided on the contact side of respectively the tensioning body and the clamping body. Said components, and thereby the device as a whole, thus derive their strength, robustness and durability from the application of a rigid form-retaining material such as a hard plastic or metal, while at the position where the clamping device will enter into contact with the instrument a relatively soft compressible shoe is provided over the associated part so as not to damage the instrument and enhance optimal force transmission thereon. For the purpose of an enhanced user comfort a further particular embodiment of the clamping device according to the invention has the feature that the operating member comprises on a free distal outer end at least a top layer of a plastic, in particular is provided with a shoe of an optionally natural elastomer.

A further particular embodiment of the clamping device has the feature according to the invention that the operating member is in engagement with an transition member and engages therewith on the tensioning body in that the transition member acts on the tensioning body, wherein the transition member is tiltable about a third tilting shaft extending substantially parallel to the first tilting shaft from the bracket. It has been found that such a transmission, wherein the transition member as it were functions as lever between the operating member and the tensioning body, is relatively light in use but nevertheless extremely accurate. In a further particular embodiment the clamping device according to the invention has the feature that at least one of the clamping body, the transition member and the tensioning body is convertible in order to adapt a mutual distance between the clamping body and the tensioning body, at least in the tensioning position, to a thickness of the neck of the instrument. The clamping device can hereby be modified to a thickness of the neck of the instrument and can thereby be utilized for instruments of diverse nature. Furthermore, the clamping force which is finally applied by the device in the tensioning position can thus be accurately set if desired.

The invention will now be further elucidated on the basis of an exemplary embodiment and an accompanying drawing. In the drawing:

figure 1 is a perspective view of an exemplary embodiment of the clamping device according to the invention;

figure 2 shows a cross-section of the clamping device of figure 1 ;

figure 3 is an exploded view of the clamping device of figure 1 ;

figure 4 is a frontal view of the clamping device of figure 1 in a release position; figure 5 is a side view of the clamping device of figure 1 in the release position; figure 6 is a frontal view of the clamping device of figure 1 in a tightened state; and figure 7 is a side view of the clamping device of figure 1 in the tightened state.

The drawings are purely schematic and not always drawn to scale. Some dimensions in particular may be exaggerated to greater or lesser extent for the sake of clarity.

Corresponding parts are designated as far as possible with the same reference numeral.

The clamping device of the exemplary embodiment according to the invention shown here comprises a form -retaining, strong bracket 10 with which the device can grip round a neck of a string instrument such as a guitar in particular. Use is advantageously made for the bracket of a metal or other robust material which resists bending and breaking when a clamping force is applied to the neck of the instrument with the device during use. Opted for here in this respect is aluminium or steel which has been brought into the desired shape by casting or machining. This also applies for the other components of the device, unless explicitly stated otherwise below.

A clamping body 20 extends transversely of bracket 10 on an upper side. The clamping body has sufficient length to span a full width of the neck of the instrument and serves to hold down the strings thereof. Clamping body 20 is provided for this purpose with a top layer 25 of rubber or another optionally natural elastomer at the position where the clamping body will enter into contact with the strung neck of the instrument. Because of the compressible character of the material applied therefor, this layer 25 is able to conform to the surface of the neck and the individual thickness of the strings, whereby a uniform transmission of force onto the strings is achieved. The relatively soft material of top layer 25 moreover provides protection against damage to the neck. A contact surface 15 of rubber or another optionally natural elastomer is also provided for this purpose on an inner side of bracket 10. This contact surface 15 is glued to a surface part formed for this purpose in bracket 15. Top layer 25 of the clamping body on the other hand covers a shoe of rubber which is placed as releasable component over clamping body 10. Top layer 25 or shoe can optionally also be adhered fixedly by being glued to the clamping body. Provided on the bracket is a medallion 40 which serves as decoration and can optionally bear a brand-name. Medallion 40 is fixed in the bracket in a cavity provided for the purpose and with a fitting pin-hole connection. Use can optionally also be made of this position to add another accessory to the device, such as for instance a light source (LED) or a plectrum holder, which can then be connected in similar manner to the bracket.

On a side lying opposite clamping body 10 the clamping device comprises a locking assembly 30 which, during use, will be situated at least substantially medially on the back of the neck of the instrument and which forms a tensioning device for the clamping device. Locking assembly 30 is formed for this purpose on an opposite outer end of bracket 10 and comprises the operating member 31 which is lined on an outer side with a shoe 32 of rubber or another optionally natural elastomer for an improved grip and contact comfort. Operating member 31,32 is tiltable about a tilt shaft 33 which extends from bracket 10 in a direction oriented substantially transversely of a neck direction of the instrument.

Operating member 31,32 can thus be manipulated roughly centrally under the neck substantially in the direction of the neck and is in engagement here, via a cavity of a precisely determined diameter formed therein, with an transition member 34. This transition member 34 is tiltable about a second tilt shaft 35 which likewise extends substantially parallel to first tilt shaft 33 from the outer end of bracket 10.

The transition member protrudes in a cavity of a tensioning member 36 which applies the final clamping tension round the neck with clamping body 20. The operating member thus acts on the tensioning body via transition member 34, which tensioning body is in turn tiltable about a third tilt shaft 37 likewise extending parallel to the first tilting shaft 33 from the outer end of bracket 10. In order to protect the neck of the instrument and for a uniform transmission of force the tensioning body is provided with a shoe or hat 38 of rubber or another optionally natural elastomer. A spring 39 between tensioning body 36,38 and transition member 34 serves to press the hinging components of the locking assembly at all times against each other.

The individual tilt shafts 33,35,37 are defined by pins provided for the purpose, see figure 3, which are designated as such in the figure and protrude into cavities or drilled holes provided for the purpose in the bracket and the associated components. These pins 33,35,37 are also the links which connect the separate main components 32.34,36 of locking assembly 30 to each other. These hinging components are advantageously formed from stainless steel or another more wear-resistant material, in particular by machining, for the purpose of an increased wear resistance and accurate dimensioning.

In figures 4 and 5 the above described clamping device with tensioning body 36,38 is shown in a release position in which no clamping force is exerted on the strings and the device can be easily removed from or placed over the neck of the instrument. Downward manipulation of operating member 31 ,32 by hand in clockwise direction urges tensioning body 36,38 into the tightened state shown in figures 6 and 7. Transition body 34 actuates the tensioning body here via the cavity formed therein, whereby a distance between tensioning member 36,38 and clamping body 20,25 is reduced and the strung neck will be clamped therebetween. By manipulating operating member 31,32 in the opposite direction the clamping device springs loose again, whereby the release position shown in figures 4 and 5 will once again be taken up.

Although the invention has been further elucidated above with reference to only a single embodiment, it will be apparent that the invention is by no means limited thereto. On the contrary, many variations and embodiments are still possible within the scope of the invention for the person with ordinary skill in the art.

A slit or groove can thus advantageously be provided in the bracket for receiving a plectrum therein. At least one of the clamping body, the transition body and the tensioning body can also be provided with an adjusting mechanism so that a distance between the tensioning body and the clamping body can be adapted to a specific thickness of the neck and/or so that the applied clamping force can be precisely adjusted. Additional functions can further be added to the clamping device, such as for instance a light source (LED) for the purpose of thereby illuminating the neck of the instrument equipped therewith, so that a desired fingering can be performed more easily, i.e. is more readily visible.

Claims

1. Clamping device for a string instrument comprising a clamping body intended and configured to lie clampingly against a strung neck of the instrument while exerting a clamping tension and comprising a tensioning device with a tensioning body which is connected via a bracket to the clamping body and is intended and configured to lie against the neck on a back thereof remote from the clamping body, wherein the tensioning body is convertible between a tensioning position, in which the neck undergoes the clamping tension between the tensioning body and the clamping body, and a release position in which the clamping tension is released, characterized in that the tensioning body is convertible by means of a manually controllable locking assembly with an operating member which is tiltable about a tilting shaft oriented substantially transversely of the neck of the instrument between at least a first position, in which there is direct or indirect engagement thereby on the tensioning body in order to urge the tensioning body into the tensioning position, and a second position whereby the tensioning body is brought into the release position, wherein the locking assembly and the first tilting shaft are provided substantially medially on the bracket on the back of the neck.

2. Clamping device as claimed in claim 1, characterized in that the tensioning body comprises a tilting body tiltable about a second tilting shaft oriented substantially transversely of the neck of the instrument, which second tilting shaft extends substantially parallel to the first tilting shaft from the bracket.

3. Clamping device as claimed in claim 1 or 2, characterized in that the clamping body is intended and configured to enter with a contact side into contact with the strung neck and comprises a compressible top layer on the contact side.

4. Clamping device as claimed in claim 1, 2 or 3, characterized in that the tensioning body is intended and configured to enter with a contact side into contact with the back of -l i the neck and comprises a compressible top layer on the contact side.

5. Clamping device as claimed in claim 3 or 4, characterized in that the clamping body, the bracket, the tensioning body and the operating member are manufactured at least substantially from an at least substantially form-retaining material, in particular a metal or a plastic, and that the top layer of respectively the clamping body and the tensioning body covers a shoe of an optionally natural elastomer provided on the contact side of respectively the tensioning body and the clamping body.

6. Clamping device as claimed in one or more of the foregoing claims, characterized in that the operating member is in engagement with an transition member and engages therewith on the tensioning body in that the transition member acts on the tensioning body, wherein the transition member is tiltable about a third tilting shaft extending substantially parallel to the first tilting shaft from the bracket.

7. Clamping device as claimed in claim 6, characterized in that the operating member comprises on a free distal outer end at least a top layer of a plastic, in particular is provided with a shoe of an optionally natural elastomer.

8. Clamping device as claimed in one or more of the foregoing claims, characterized in that at least one of the clamping body, the transition member and the tensioning body is convertible in order to adapt a mutual distance between the clamping body and the tensioning body, at least in the tensioning position, to a thickness of the neck of the instrument.