The present invention relates to tuning pin blocks for instruments, and more particularly, though not exclusively, to tuning pin blocks in pianos.

In this connection, the tuning pins of pianos have historically been inserted in one or more wooden blocks set into the cast iron frame of the piano, across the width of the registers of the instrument.

Stability of tuning is critically dependent on the firmness of location of the wood in the frame. In some instances for grand pianos, the wood is exposed through an aperture in the upper surface of the frame extending over a plurality of tuning pins and in other instances each pin is situated in a clearance hole in the frame, sized so the pin can be inserted without touching the encapsulating cast iron frame. The former concept with an aperture, called the open plank system, permits the height of the string above the wood block to be minimal and thus the bending moment on the pin to be minimal . The latter concept called closed plank system provides a more rigid encapsulation of the block in the cast frame and usually is combined with a collar between the pin and the casting to take some of the bending moment applied to the pin by the string .

Piano tuners have developed skills with both these concepts of tuning pin installation and are adept at knowing how to achieve the correct and uniform tension in the full length of each string required to tune the instrument optimally.

However, in order to ensure stability of tuning and quality of sound, conventional tuning blocks in their associated castings tend to be large, heavy and unwieldy components which restrict portability of the instrument as a whole and which have a limited lifespan due to the tuning block material losing its properties. As such, their replacement within the instrument is often so difficult or so costly as not to be commercially viable, meaning the whole instrument has a shortened lifespan. Furthermore the requirements of the tuning pin block can place constraints on the design of instruments incorporating them .

The present invention seeks to alleviate problems with such known tuning pin blocks.

According to a first aspect of the present invention there is provided a tuning pin block assembly for a piano, the assembly comprising :- one or more elements formed of wood based material, plastic or other material suitable for holding a tuning pin, the one or more elements having multiple bores for receiving tuning pins, said elements being provided within a fibre composite material. In this manner, a tuning block having reduced weight and optimised strength but conventional tuning characteristics can be achieved .

Preferably, said fibre composite material is carbon fibre or another stiff and strong fibre composite material.

Conveniently, each of said one or more elements is formed of any one of multiply maple, resin bonded or impregnated plywood, or any other suitable tuning pin block wood .

Preferably, a plurality of said wood material elements are substantially encapsulated within said fibre composite material .

To reduce any deflection caused by tension from the strings, the assembly may take the form of a block having reinforced or stiffened front and rear faces, with respect to the line, direction, plane of the strings. Conveniently, the block is provided with a front reinforcing plate fibre composite member along its front face, with respect to the approximate string alignment.

The block may be provided with a rear reinforcing plate fibre composite member along its rear face.

The tuning block assembly may further comprise a block of wood material encapsulated within a membrane of fibre composite material . This may comprise a single block.

Preferably, the fibre composite material membrane is between 2 and 1 2 mm thick.

Alternatively, the tuning block assembly may comprise a block of fibre composite material plugged with a plurality of wood material dowels each located to receive a tuning pin.

Preferably, said dowels each have a diameter of between 1 0 to 30 mm.

The present invention further encompasses a method of forming a tuning pin block assembly as defined above, comprising the steps of :- forming a block of fibre composite material having a plurality of apertures; curing said block; and plugging each of said apertures with wood based material, plastic or other material suitable for holding a tuning pin.

Preferably, said apertures are cylindrical bores and the plugging material is provided as a plurality of dowels of wood based, plastic or other material suitable for holding a tuning pin. Conveniently, the plurality of dowels each have a diameter in the range 1 0 to 30 mm .

The dowel material is preferably bonded within the plurality of apertures.

The method conveniently further comprises bonding one or more front and/or rear reinforcing plate members to front and rear faces of the tuning pin block.

Conveniently, the method further comprises the steps of :- encapsulating a block of wood material within a membrane of fibre composite material .

Preferably, the membrane is cured in a vacuum furnace at a temperature of 1 00 to 1 60 degrees Celsius.

The membrane assembly may be cured for a period of 1 to 20 hours.

The method may further comprise bonding front and/or rear reinforcing plate members to front and rear faces of the encapsulated block.

The present invention furthermore encompasses a piano having a tuning pin block assembly as defined above.

Examples of the present invention will now be described by way of example and with reference to the accompanying drawings, of which:-

Figure 1 shows a perspective view of certain main components of a piano according to the present invention; and

Figure 2 shows a vertical cross-sectional view through the tuning block assembly of the piano of Figure 1 along lines X-X. As shown in Figure 1 , a piano 1 includes a case 2 having top and sides, a key bed 3 for housing a keyboard and action (not shown) and a tuning pin block assembly 4.

The tuning pin block assembly is shown in more detail in Figure 2. In this connection, the tuning block assembly includes one or more elements 5 for receiving tuning pins (not shown), the one or more elements being formed of a material having wood-like properties. These one or more elements are provided within a fibre composite material 6, such as carbon fibre.

In this regard, the present invention concerns a carbon fibre or other composite material pin block concept that offers the tuner virtually conventional feel on the pins when tuning, yet enables a tuning pin block of high strength to be made using comparatively light composite fibre material such as but not exclusively carbon fibre.

Pianos made in this manner with such composite fibre material, by virtue of its stiffer and stronger material properties, offer piano designers the option to eliminate or reduce certain frame reinforcing bars that necessarily separate zones of strings into three or more groups called breaks in conventional pianos.

It is well known that at the ends of such breaks the sound quality of the notes may vary. A piano without such reinforcing bars will not suffer this defect but does require a very strong member in the tuning pin block region of the casting to retain the tuning pin block without it being bent or deflected by the string tension loads. That extra strength has hitherto carried with it a weight penalty for the piano that has generally been found unacceptable.

With a first embodiment of the present invention as shown in Figure 2, a tuning pin block construction is used in which one or more pieces of multiply maple wood or of resin impregnated plywood or any conventional tuning pin wood material is encapsulated in a membrane 6 of carbon fibre approximately 2 to 1 2mm thick. The carbon fibre material must be cured after application to the wood . The temperature and time for which curing is done must not degrade the wood material . 1 25 to 1 50 degrees Celsius for a period of 1 to 6 hours is typically but not exclusively found to be satisfactory.

The encapsulated block assembly is further reinforced on its front and rear vertical faces by bonding thick carbon fibre bar material 7, 8, 9 to these faces in a manner to form the double web section of a box girder of high strength. The web material in such girder is little stressed by bending load application and therefore any minor lack of material properties resulting from curing as above at perhaps below optimum temperature for the carbon fibre material is of little significance.

In an alternative embodiment, for example for use but not exclusive use with grand pianos that have high tension stringing or which have extended register keyboards, the strength of the tuning pin block assembly in bending may be greatly enhanced by forming the pin block from a solid member of fibre composite material such as carbon fibre and providing it with suitably sized holes at each position for a tuning pin . After curing, each hole is plugged with a geometrically identical wood or fibre dowel typically for circular dowels twice the diameter of the tuning pin and usually but not exclusively in the size range 1 0 to 30mm diameter bonded to the carbon fibre cylindrical surface of the hole. The material and orientation of the plies of the dowel being substantially the same as that conventionally used in pin blocks. The finish formed plugged board is bonded to front and rear carbon fibre plate material of substantial thickness to form a stiff box girder spanning the registers of the piano. This concept of a piano tuning pin block assembly ensures that the tuner will experience the same or very similar feel to the pins as if he/she were tuning conventional instruments with the pins inserted directly into a one or two piece conventional wooden tuning pin block.

The present invention hence concerns a piano tuning pin block of carbon or other fibre composite material, that offers the tuner conventional feel for the movement and adjustment of the tuning pins.

The tuning pin block can be made by encapsulating multiply wood block material of the type normally used in piano tuning pin blocks in a carbon fibre membrane.

The encapsulated block can be further strengthened by bonding on additional carbon fibre bar material to form a box girder structure of great stiffness orientated to carry tensile forces from the piano strings.

Further additional carbon fibre material can be attached by bonding to form attachments and mountings etc. for other features and parts of the piano.

Alternatively, the tuning pin block may be formed of solid carbon or other fibre composite material and in which holes are formed to receive dowels of plastic or ply wood or fibre material so that tuning pins may be mounted in a manner in which each pin is central in a hole in the carbon fibre block and is surrounded and held by a collar of appropriate tuning pin material encapsulated and bonded into the carbon fibre.

The block membrane assembly together with the multiply wood material may be cured in a vacuum furnace at a temperature of 1 25 to 1 60 degrees Celsius for a period of 1 to 6 hours.