GB2297144A - Valves for musical wind instuments - Google Patents

Abstract

A method is for making a movable valve member for a musical wind instrument valve unit of the type having a casing with a plurality of windways extending therefrom and a valve member with passageways therethrough, the valve member being movable within the casing to permit the passageways to make alternative connections between the windways. The method comprises forming a mould having apertures in the wall thereof at positions corresponding to the positions of the windways in the valve casing, locating the casing A1 of the valve member in the mould, locating removable cores to extend between pairs of the apertures, each core defining the shape of the passageway in the valve member, introducing a hardenable liquid into the mould and, after hardening of said liquid, removing the valve member from the mould and removing the cores from the member. Further, a method of making a musical wind instrument valve casing, comprises locating a core in a mould, the core being shaped to form the internal shape of the casing and being provided with recesses at positions corresponding to the positions of the external windway connections, locating in the mould sleeves for connection of the external loops in the completed instrument, positioning between each sleeve and one of the recesses a removable plug to define in the completed casing a passageway between the sleeve and the valve, introducing a hardenable liquid into the mould and, after hardening of the liquid, removing the valve casing from the mould and removing the plugs from the casing.

Description

VALVES FOR MUSICAL WIND INSTRUMENTS Field of the Invention This invention relates to methods of making movable valve members and valve casings for valves for musical wind instruments, for example brass instruments such as trumpets, cornets, horns, baritones, euphoniums, bombardons and valve trombones.

Background to the Invention In brass instruments, the musical notes which can be produced are determined by, amongst other things, the length of the air column in the instrument. The air column extends within the instrument from the mouthpiece to the bell. For a given length of air column, the available notes will be determined by the vibrational modes of the tube, and so the range of notes which can be produced is very limited. The army bugle, for example, being a simple fixed length tube, has a very limited repertoire.

In order to provide the twelve semitone intervals to the octave upon which modern western music is based, the trumpet, and others of the brass instrument family, use valves selectively to add in different extensions to the basic air column by connecting additional loops of tube into the basic length of tube.

Two different types of valve are commonly used in modern instruments. These are the piston valve and the rotary valve, and each includes a movable valve member in a valve casing to which the external loops are connected. The valve member contains passageways ("cockades") to connect alternative pairs of external windways ("knuckles") according to the position of the valve member.

Typically, a piston for a piston valve is manufactured by forming the piston as a hollow tube with apertures in its wall corresponding to the positions of the external windways. It is important in the design of valves to avoid constrictions and sharp changes of direction, since these can adversely affect the tonal quality of the instrument. The connections within the tube between the apertures are formed by appropriately shaped sections of pipe, generally referred to as cockades, which are fixed in position by brazing or silver soldering. This process, and the subsequent finishing process to remove excess metal from the exterior of the piston to provide a smooth valve surface, require considerable precision, and are timeconsuming and so contribute significantly to the cost of the instrument.

Rotary valve members are generally formed by building up in a manner similar to the build up of piston valves, hereinbefore described, but can, for a simple rotary valve, be milled from a solid cylinder of metal.

In either case, the process again requires great precision, and is therefore costly.

Summary of the Invention One aspect of the invention provides a method of making a movable valve member for a musical wind instrument valve unit of the type having a casing or barrel with a plurality of windways extending therefrom and a valve member with passageways therethrough, the valve member being movable within the casing to permit the passageways to make alternative connections between the windways, the method comprising forming a mould having apertures in the wall thereof at positions corresponding to the positions of the windways in the valve casing, locating removable cores in the mould to extend between pairs of the apertures, each core defining the shape of the passageway in the valve member, introducing a hardenable liquid into the mould and, after hardening of said liquid, removing the valve member from the mould and removing the cores from the member.

In one method of the invention, the cores each comprise a bendable rod or cylinder such as to form an even curve between the apertures. The cores are suitably resiliently bendable and are preferably solid. Plastics and rubber materials are preferred, and silicone rubbers are especially preferred, and may be lubricated to facilitate their removal from the valve member.

In an alternative method according to the invention, the cores are formed from a material such as wax which can readily be removed from the hardened valve member by heating to a temperature high enough to melt the wax but low enough to avoid damage to the newly created valve member.

In a second alternative method according to the invention, the cores are formed from a material such as icing sugar which can readily be removed from the hardened valve member by immersing the member in a solvent (warm water, in the case of icing sugar) to dissolve the core.

The valve member may be formed with a metal outer curved surface by first locating in the mould a metal sleeve provided with apertures corresponding to those in the mould, and then locating the cores in the sleeve.

The second aspect of the invention provides a method of making a musical wind instrument valve casing, comprising locating a core in a mould, the core being shaped to form the internal shape of the casing and being provided with recesses at positions corresponding to the positions of the external windway connections, locating in the mould sleeves for connection of the external loops in the completed instrument, positioning between each sleeve and one of the recesses a removable plug to define in the completed casing a passageway between the sleeve and the valve, introducing a hardenable liquid into the mould and, after hardening of the liquid, removing the valve casing from the mould and removing the plugs from the casing.

The mould is preferably a two or more part mould, the core and sleeves being located in one or more parts before assembly of the parts together. The plugs are suitably lengths of flexible silicone rubber rod so as naturally to form a uniform curve between the sleeve and the valve.

The core may be formed from a plurality of separable components assembled together.

Preferably a plurality of valves are moulded together as a single unit, a plurality of separate cores being used. For example, a typical trumpet will have three valves, and these can readily be moulded as a single unit. Connecting knuckles or colundairs between the valves may also be moulded by a plug extending from a recess in one valve and, where appropriate, to a recess in another valve.

The valve casing may be formed with a metal inner liner by first locating in the mould upon the individual valve core a metal sleeve or barrel provided with apertures corresponding to those created in the mould by the mould plugs, and allowing the inner ends of the plugs to enter the said sleeve, in which case only the core will be removed from within the sleeve, requiring only the usual grinding in of the valve member on assembly to ensure a satisfactory seal with sufficient ease of movement.

The hardenable liquid in either of these aspects of the invention is preferably a plastics material, for example an acrylic resin or a polyester resin. Generally, any self-hardening resin will be suitable. Curing may be initiated or accelerated by the application of heat, where the cores are not formed of a readily meltable material such as paraffin wax. In order to minimise weight, the resin may be foamed or filled with an expanded filler, provided that care is taken to render the surface of the passageways in contact with the wind in the instrument smooth and free from any defects or recesses which might adversely affect the tonal quality of the instrument.

Where the resin is such as to shrink slightly in curing, allowance can be made for the shrinkage by decreasing or increasing slightly the dimensions of the components in the mould and its cores, according to the direction of shrinkage.

The methods of the invention are applicable to the manufacture of both piston and rotary valves.

The invention is applicable to all types of valve, including relatively complex structures such as the compensating valve designed by D. J.

Blaikley in 1874 and still employed in instruments manufactured by Boosey and Hawkes. (See P. Bate, "The Trumpet and Trombone", Benn, London, 2nd edn. 1978, page 179) Brief Description of the Drawings In the drawings, which illustrate examples of the valves and methods of manufacture in accordance with the invention: Figure 1 is a sectional elevation of a piston valve member; Figures 2, 3 and 4 are sections on lines X-X, Y-Y and Z-Z respectively in Figure 1; Figure 5 is a sectional elevation of a piston valve casing with the middle valve loop omitted for the sake of clarity; Figure 6 is a sectional plan of the casing shown in Figure 5; Figure 7 is a sectional plan of a rotary valve casing; Figure 8 is a sectional plan of a rotary valve member; Figure 9 is an end view of the valve member shown in Figure 8; and Figures 10-14 are sectional elevations of individual valve casings illustrating five different embodiments of another aspect of the invention; Detailed Description of the Illustrated Embodiments Referring first to Figures 1 to 4, the valve member comprises a cylinder Al, the outer surface of which slides within and forms sealing contact with the valve casing. Contained within the cylinder Al is a solid body of plastics material P through which are moulded the air passageways A2 corresponding to the cockades in conventional valves. The upper end of the cylinder Al is closed off by a top disc A4. A spring shank A5 extends from the upper end of the cylinder, and is surmounted by the neck A6 and touchpiece A7 in conventional manner.As may be seen more clearly from Figures 2, 3 and 4, three cockade passageways A2 pass through the valve member, the openings being indicated by B for those at the back of the member as illustrated in Figure 1, L for those opening to the left, and R for those opening to the right. The openings are conventionally at approximately 1200 separation.

The passageways A2 are formed in the cylinder Al by locating the cylinder in a corresponding cylindrical mould having apertures in the wall thereof corresponding to the openings in the wall of the cylinder. The apertures are angled so that a silicone rubber rod passed through the apertures and through the cylinder is held to form a smooth uniform curve between the openings, and thus the smallest resistance to air flow across the valve. A hardenable plastics resin, for example a resin/hardener (catalyst) mix, is then poured into the cylinder Al to fill it uniformly around the cores, if necessary vibrating and/or applying a vacuum to remove entrained bubbles of air. After the resin has gelled, the cores are removed carefully, and the resin is then allowed to cure fully.A thin metal disc may be inserted into the cylinder after one silicone rubber rod has been inserted, and before the next is inserted, to ensure that there is no risk of "break through" between adjacent cockade tubes.

Figures 5 and 6 show a piston valve unit manufactured in accordance with the invention, comprising the casings for the three valves of a typical modern trumpet. The casings or barrels B1 are provided with sleeves C1 for connection of the external loops or slides providing the additional lengths of air column selectable by the valves, and with sleeves D1 at each end for connection of the tubes leading from the mouthpiece and to the bell. Adjacent barrels are interconnected by short sections of tube known as colundairs B5. The sleeves C1 and D1 are connected to the respective barrels by knuckles B4 moulded within the plastics material.

The barrels B1 are each closed at their ends by caps B2 and B3, which are conventionally screw-threaded on, either by external threads on the barrels, or preferably by internal threads to prevent damage to the threads in use.

The valve unit is formed in accordance with the invention by positioning the barrels B1 in spaced relation in a mould, with removable cores passing through the openings in the walls of the barrels and into the respective sleeves or, in the case of the colundairs B5, in a curve to enter the opening in the adjacent barrel. External locations in the mould walls ensure that the sleeves are all accurately aligned, so that the slides and other parts of the instrument can be correctly connected. The mould is then closed and a hardenable plastics resin is introduced and allowed to gel, as in the formation of the valve piston, described hereinbefore with reference to Figures 1 to 4. The unit can then be removed from the mould and the cores removed from it to yield the completed unit. The plastics resin is allowed to cure fully before the unit is prepared for use in the normal manner.

Figure 7 illustrates a valve unit corresponding to that shown in Figures 5 and 6, but with rotary valves instead of piston valves. Components corresponding to those in the piston valve embodiment have the same reference numerals. The barrels B1 are each provided with four windway entries spaced around the circumference and in the same plane.

Figures 8 and 9 illustrate the rotary valve member, which is formed in a similar manner to the piston illustrated in Figures 1 to 4. A metal cylinder Al is formed with openings through the curved wall thereof corresponding to the entries to the windways. Flexible rods of silicone rubber are inserted through the openings, in pairs, and are shaped to provide a uniform curve between the openings. Plastics resin liquid is then poured into the cylinder to fill it and cover the rods, and is allowed to gel. The rods are then withdrawn. The top plate A4 is provided with a lever connection in conventional manner, to permit the valve member to be rotated in use by a lever action, using a suitably positioned key on the instrument.

The valve member can be used in an identical manner to the conventional metal fabricated or machined valve member.

Claims (14)

1. A method of making a movable valve member for musical wind instrument valve unit of the type having a casing with a plurality of windways extending therefrom and a valve member with passageways therethrough, the valve member being movable within the casing to permit the passageways to make alternative connections between the windways, the method comprising forming a mould having apertures in the wall thereof at positions corresponding to the positions of the windways in the valve casing, locating removable cores in the mould to extend between pairs of the apertures, each core defining the shape of the passageway in the valve member, introducing a hardenable liquid into the mould and, after hardening of said liquid, removing the valve member from the mould and removing the cores from the member.

2. A method according to Claim 1, wherein the cores each comprise a bendable rod or cylinder such as to form an even curve between the apertures.

3. A method according to Claim 2, when the cores are resiliently bendable.

4. A method according to Claim 1, wherein the cores are formed from a material which can be melted at a temperature which will not adversely affect the valve member.

5. A method according to any preceding claim, comprising first locating in the mould a metal sleeve provided with apertures corresponding to those in the mould, and then locating the cores in the sleeve before introducing a hardenable liquid into the sleeve.

6. A method of making a musical wind instrument valve casing, comprising locating a core in a mould, the core being shaped to form the internal shape of the casing and being provided with recesses at positions corresponding to the positions of the external windway connections, locating in the mould sleeves for connection of the external loops in the complete instrument, positioning between each sleeve and one of the recesses a removable plug to define in the complete casing a passageway between the sleeve and the valve, introducing a hardenable liquid into the mould and, after hardening of the liquid, removing the valve casing from the mould and removing the plugs from the casing.

7. A method according to Claim 6, wherein the mould is a two or more part mould, and the core and sleeves are located in one or more parts before assembly of the parts together.

8. A method according to Claim 6 or 7, wherein the plugs are lengths of a resiliently flexible material.

9. A method according to Claim 6, 7 or 8, comprising moulding a plurality of valves together as a single unit.

10. A method according to Claim 9, comprising forming connecting knuckles or colundairs between the valves by first locating a plug in the mould between a recess in one valve and a recess in another valve.

11. A method according to any of Claims 6 to 10, comprising locating in the mould upon the or each individual valve core a metal sleeve provided with apertures corresponding to these created in the mould by the mould plugs, and allowing the inner ends of the plugs to enter the said sleeve, and after hardening of the hardenable liquid, removing the core from within the sleeve.

12. A method according to any preceding claim, wherein the hardenable liquid is an acrylic resin or a polyester resin.

13. A method of making a movable valve member for a musical wind instrument, substantially as described with reference to, or as shown in, the drawings.

14. A method of making a musical wind instrument substantially as described with reference to, or as shown in, the drawings.