GB2512339A

GB2512339A - A capo

Info

Publication number: GB2512339A
Application number: GB1305542.1A
Authority: GB
Inventors: Nicholas John Campling
Original assignee: C7th Ltd
Current assignee: C7th Ltd
Priority date: 2013-03-27
Filing date: 2013-03-27
Publication date: 2014-10-01
Anticipated expiration: 2033-03-27
Also published as: GB201305542D0; GB2512339B

Abstract

A capo, for use with a stringed instrument such as a guitar, comprising a clamping bar 10 to extend across a finger board over the strings and a pliable strap 11 arranged to extend around the neck. In order to join open ends of the clamping bar 10 and strap 11 a fastening means 14 is provided, preferably in the form of a threaded shaft 15 that abuts against a groove or notch 21 in the clamping bar. To reduce friction and thereby enable smooth movement of the strap against the instrument neck an inside surface 20 of the pliable strap is made from or coated with a non-stick material, such as polyurethane or PTFE. Preferably the clamping bar and strap are made substantially in one piece from plastic, such as glass-filled nylon, where the thickness is varied to give rigidity or flexibility/resilience where required. The strap, and any other instrument facing portion of the capo, may include a resilient elastomeric material for providing a cushioning effect against the stringed instrument.

Description

A CAPO

The present invention relates to a capo for a stringed musical instrument, in particular a low cost capo for use with a guitar or banjo.

BACKGROUND TO THE INVENTION

A capo (sometimes referred to as a capodastro, capodaster, capotasto or cejilla) is a well-known device used with a stringed instrunient, for example a guitar or banjo, that has a neck and a set of strings extending along the length of the neck above a fingerboard. The capo, when applied to the instrument, serves to clamp the strings against the finger board of the neck and, in particular, between or against one of the numbers of fret bars disposed along the length of the finger board. In practice a capo serves to reduce the effective length of the strings and therefore raise the pitch of the instrument as the capo is clamped in any suitable position toward a bridge located beyond an end of the finger board.

A large number of different capo types are known, each of which has a different advantage and technical consideration. Players often have a preference for a particular capo type based on its ease of use, effectiveness and cost/availability. Some capo types (e.g. with lever arms and/or clutch mechanisms) become complicated and expensive to manufacture and, hence, there is always a market need for a simple but effective low cost mechanism integrated into a capo.

A particular simple capo design is described by US 6410832. This device utilises a resiliently bendable tensioning strap that connects generally perpendicularly at one end of a bar to be positioned over the strings. The other end of the strap includes a fastening means in the form of a conical nut mounted over a screw thread which abuts a notched end of the bar to result in a clamping mechanism against the strings.

There are problems associated with this type of capo, namely that the spring steel strap is known to break where it is connected to the clamping bar after prolonged use.

Furthermore, the spring steel strap can easily damage the back of the guitar neck because the hard surface of the spring steel, even though coated, is capable of depressing or gouging into the surface lacquer.

SUMMARY OF THE INVENTION

The present invention seeks to provide a capo that will overcome the problems identified

in the prior art.

In one broad aspect of the invention there is provided a capo as described in the accompanying claims.

Particularly, the capo of the invention is for use with a stringed instrument having a neck with a finger board, a back and strings that extend longitudinally over said finger board, the capo being primarily constructed with a clamping bar configured to, in use, extend across the finger board over the strings; a pliable and preferably resilient strap connected with and extending at an angle to the clamping bar and arranged to extend around the neck; and a fastening means provided to removably attach a distal end of the flexible strap with a distal end of the clamping bar; wherein at least an inside surface of the pliable strap is made from or coated with a non-stick material for contacting the back of the neck.

Preferably a substantial portion of the clamping arm and strap are formed in one component from a plastic material, e.g. glass filled nylon. In such a case, the thickness can be varied to give rigidity or flexibility where required. However, while pliable and somewhat resilient in one plane of movement, the strap is preferably not otherwise stretchable such that its length is able to be pulled to extend and thereby provide a biasing force for enabling the clamping action of the capo.

Preferably, at least the strap but also any instrument facing side of the capo, includes a resilient elastomeric material for providing a cushion effect. Accordingly, the combined construction of the invention provides a soft strap which will not cause any damage to the instrument neck, however, the addition of the non-stick coating/material ensures that while there is non-damaging contact, the strap is still able to slip over the back of the neck to allow the force on the strings to even out as the capo is applied.

Preferably, the strap thickness is tapered to a thicker terminal portion where it is connectable via the fastening means to the clamping arm and thinner where it is in contact with the back of the neck and/or where it is integral or connected at an angle with the clamping bar. This construction spreads the stress along the strap as it is flexed backward to allow removal of the capo from the instrument neck so as to reduce the stress at any given point below a level which would cause fatigue and breakage.

Preferably the non-stick coating is a matt polyurethane, e.g. a product or equivalent as supplied by Dongguan City Betterly New Materials Co. Ltd (part no. BT-18O).

Alternatively, the coating or material may be Polytetrafluoroethylene (PTFE).

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates plan, side and end elevation views of a capo according to a preferred embodiment of the invention; Figure 2 illustrates an "open" state of the capo from Figure 1; Figure 3 illustrates a perspective view of a capo from Figures land 2; Figure 4 illustrates a section view of the capo from the preferred embodiment; Figure 5 illustrates a general view of the capo without the complete fastening mechanism;

DETAILED DESCRIPTION OF THE INVENTION

Figures ito 5 illustrate various views of a preferred embodiment of capo according to the invention. As shown, the capo includes a clamping bar 10 that, in use, is to be positioned over the fret board and strings of an instrument (not illustrated). Extending at one end and underneath the clamping arm lOis a strap 11 including a substantially flexible portion 12 that is able to bend around a neck of the instrument (not illustrated). Strap 11 terminates in a thicker portion 13 which receives or otherwise accommodates a fastening mechanism 14.

In the illustrated form fastening mechanism 14 is comprised of a threaded-end shaft 15 to be received by a nut 16 or equivalent internally threaded member, located within the thick end portion 13 of strap 11. An adjusting head 17 atop shaft 15 enables manipulation of the shaft into and out of nut 16 for tightening purposes and also provides an abutment surface 18 against which a notched end 21 (best seen in Figure 5) of clamping bar 11 is abutted.

In the preferred form clamping bar 10 and strap 11 are moulded from a single piece of plastic material that, by virtue of its dimensions, can provide the requisite pliability in the strap 12 and rigidity in clamping bar 11 and thick end portion 13. Preferably the main body material is glass reinforced nylon.

As is visible in the section view, Figure 4, an overmould material (e.g. silicone rubber) 19 is applied over the substantive surface of strap 11, extending to the underside (string contacting) surface of clamping bar 11. This overmould material 19 provides a cushion effect to avoid damage to the neck and strings/finger board. However, dependent on the main body material chosen, a non-damaging surface effect could also/alternatively be inherent in the one piece plastic construction.

A series a small cavities 22 in clamping bar 10 are visible in the cross section view, Figure 4. These are simply openings that, along with a longitudinal slot 23 on the underside of clamping bar 10, provide a receiving structure for the overmould material to flow into and hence create a more secure bond. It will be apparent that the slot and cavities are not visible when the overmould 19 is in place, as seen in all figures except Figure 4.

A non-damaging elastomeric material as used in the overmould 19 usually has a high friction value surface and therefore prevents slippage of the strap relative to the instrument neck. Such a situation, i.e. traction between the strap and back of neck, causes problems for obtaining an even distribution of force and is, hence, undesirable.

Therefore, according to the invention, a non-stick or otherwise slippery material/coating denoted by reference numeral 20 is additionally applied to at least the neck contacting surface of strap 11.

It is apparent that the widened portion 13 at the terminal end of strap 11 is shaped to conform to the arc of an instrument neck. The complimentary opposite side of the neck-accommodating arc is formed by the flexible strap 12 bending around said neck.

However, the strap 11/12 is intended to be moulded in a "closed" position (Figures 1, 3, 4 and 5) as opposed to an "open1' position (Figure 2) such that its general resilience holds it closed and the capo can be temporarily stored behind the nut of the guitar, while still readily available for use. It will be apparent that the resilience/pliability of strap 12 must be at least sufficient to enable the capo to be located onto a guitar neck.

While resilience/pliability in portion 12 allows movement between open and closed positions as illustrated, strap 11 is not intended to be generally stretchable or otherwise extend able.

It will be apparent that the invention enables a relatively simple and low cost capo design to be manufactured using available materials and processes. The non-stick surface coating is preferably polyurethane or equivalent.

Claims

CLAIMS: 1. A capo for use with a stringed instrument having a neck with a finger board, a back and strings that extend longitudinally over said finger board, the capo including: a clamping bar configured to, in use, extend across the finger board over the strings; a strap connected with and extending at an angle to the clamping bar and arranged to extend around the neck; and a fastening means provided to removably attach a distal end of the flexible strap with a distal end of the clamping bar; wherein at least an inside surface of the pliable strap is made from or coated with a non-stick material for contacting the back of the neck.
2. The capo of claim 1 wherein the non-stick material is polyurethane or PTFE.
3. The capo of claim 1 or 2 wherein the clamping arm and strap are substantially formed in a common piece.
4. The capo of claim 3 wherein the common piece is formed from glass filled nylon.
5. The capo of any preceding claim wherein a portion of the strap is pliable and/or resilient, leading to a thicker terminal portion where it is connectable via the fastening means to the clamping arm.
6. The capo of any preceding claim wherein the strap includes a resilient elastomeric material for providing a cushion effect against the instrument.
7. The capo of any preceding claim wherein any instrument facing portion of the capo includes a resilient elastomeric material for providing a cushion effect against the instrument.
8. The capo of claim 5 wherein the thickness of the pliable/resilient portion of the strap is tapered to the thicker terminal portion where it is rigid and connectable via the fastening means to the clamping arm.
9. The capo of claim 8 wherein the pliable/resilient portion of the strap is thin, relative to the thicker terminal portion, at least where it is in contact with the back of the neck and/or where it is integral or connected at an angle with the clamping bar.
10. The capo of any preceding claim wherein the fastening means is comprised of a shaft with a threaded end and a head, received for longitudinal adjustment into a corresponding internal thread set into either the strap or clamping arm.
11. The capo of claim 10 wherein either the clamping arm or strap includes a notch to abut with the shaft and/or head.
12. The capo of any preceding claim wherein the clamping arm and strap are formed in a closed configuration such that resilience in the strap can enable the capo to move to an open position.
13. A capo substantially as herein described with reference to the accompanying drawings.