Abstract:
A musical instrument valve having two flexible, movable sound tubes in a casing is disclosed. By actuating a finger button, a musician can reposition the tubes to include a slide loop in the instrument&#39;s sound path.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a flexible tube switch, and more specifically, to a flexible tube valve for use in a musical wind instrument. 
     Simple flexible tube switches have been used in musical instruments previously. For example, U.S. Pat. No. 3,933,078 to Veneklasen at FIGS. 11a and 11b, shows the use of such a switch in a French horn of unique design. Such prior art uses incorporate a single tube having one end fixed and the other end free to move between two positions. These switches are not suitable to replace the standard valves of a normal French horn, trumpet or similar brass instrument because they can only change the course of a single air passageway. 
     Standard brass wind instrument valves are either piston or rotary type valves which include a piston or rotor with multiple passages extending therethrough. When activated such valves interrupt the passage of sound waves from an instrument&#39;s lead pipe to its main bore by routing the waves from the lead pipe, through a slide loop, then back into the main bore. The pistons or rotors of such valves are typically machined from solid blocks of metal and include a variety of tortuous passages which are difficult to produce. Such standard valves require frequent lubrication and other maintenance. 
     SUMMARY OF THE INVENTION 
     The present invention is a valve which includes two flexible tubes within a single valve body. This new flexible tube valve performs the same task as a standard brass wind instrument valve, but may be constructed at lower cost and requires less maintenance. 
     It is an object of the present invention to provide a valve of simple design which can be made from a variety of materials, including synthetic plastics. 
     A further object is to provide a valve which is essentially maintenance free and which requires lubrication only infrequently. 
     An additional object is to provide a valve having flexible tubes which extend in a substantially straight path through the valve body. 
     Other advantages and objects of this invention will become apparent to those skilled in the art upon reading the specification. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a partially broken away side view of a valve according to the present invention with its slide plate in a first or raised position; 
     FIG. 2 is a partially broken away side view of the valve shown in FIG. 1 with its slide plate in a second or lowered position; 
     FIG. 3 is a top view of the valve shown in FIG. 1; 
     FIG. 4 is a sectional view taken along lines 4--4 of FIG. 1; 
     FIG. 5 is a sectional view taken along lines 5--5 of FIG. 2; 
     FIG. 6 is a sectional view taken along lines 6--6 of FIG. 2; 
     FIG. 7 is an enlarged, partial view of one of the flexible tubes shown in FIG. 2; 
     FIG. 8 is a plan view of a B-flat bass trumpet incorporating three valves of the type shown in FIG. 1; 
     FIG. 9 is an enlarged view of the valve assembly, including slide loops, of the trumpet shown in FIG. 7; 
     FIG. 10 is a top view of the valve assembly shown in FIG. 8; and 
     FIG. 11 is a back view of the valve assembly shown in FIG. 8. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The valves of a brass wind musical instrument are adapted to selectively insert or remove a slide loop from the instrument&#39;s sound path. Each such valve includes a casing to which is connected a lead pipe which extends from a mouthpiece, a main bore which terminates in the instrument&#39;s bell, and both ends of the slide loop. Inside the casing is located a finger-actuated valve mechanism which can, alternately, connect the lead pipe directly to the main bore or connect opposite ends of the slide loop to the lead pipe and main bore respectively. 
     Interior details of the novel valve according to the present invention are shown in FIGS. 1 through 6. This valve has a casing 20 which includes a first end plate 22, the interior face of which defines an elongated contact surface 24. Primary and secondary contact surface apertures 28, 30 extend through the plate 22. 
     At the opposite side of the casing 20 is located a second flat end plate 34 which is parallel to the first end plate but spaced therefrom so that a valve chamber is formed between the two end plates. The second end plate 34 defines primary and secondary tube-anchoring apertures 36, 38. 
     Inside the casing is a primary flexible tube 42 which connects a primary slide plate aperture 50 defined by a slide plate 56 to the primary anchoring aperture 36. Also included inside the casing is a secondary flexible tube 46 which connects a secondary slide plate aperture 52 defined by the plate 56 to the secondary anchoring aperture 38. 
     The slide plate 56 has an elongated contact face 58 which is slidably positioned against the contact surface 24 in such a manner that the plate apertures at the contact face 58 and the surface apertures at the contact surface 24 are always located in a common plane. A shaft 66 extends upwardly from the slide plate 56 and terminates in a button 68 so that the slide plate can be manually moved between first and second playing positions. 
     As shown in FIG. 1, the slide plate 56 normally rests in a first or raised position wherein the primary slide plate aperture 50 registers with the primary surface aperture 28. When the button 68 is depressed, the slide plate moves to a second or lowered position wherein the primary slide plate aperture 50 registers with the secondary surface aperture 30 and the secondary slide plate aperture 52 registers with the primary surface aperture 28. Stops 69 at the top and bottom of the casing limit the travel of the slide plate 56 so that the appropriate slide plate apertures will exactly register with surface apertures when the button 68 is fully depressed and the primary plate aperture will exactly register the primary surface aperture when the button is released. Springs 70, inside the casing, urge the slide plate upwardly toward the first position and also horizontally toward the first end plate 22 so that the contact face 58 remains against the contact surface 24. 
     Flexible tubes for use with the aforesaid valve must easily compress longitudinally as the slide plate moves between its two positions. Suitable tubes, as shown in FIG. 7, comprise helical springs bound to a tubular elastomeric substrate. Such a tube may be formed by wrapping a mandrel with a layer of nylon mesh 72 of the type used in women&#39;s stockings, winding a nylon or glass filament 73 around the mesh to form a helix, and then coating the filament and mesh with a layer 74 of silicone cement which is flexible when set. After the cement sets and the mandrel is removed, to leave a tube that is radially firm, but highly longitudinally compressible. 
     Referring now to FIGS. 8 through 11, it can be seen how the previously described valve can be incorporated into a brass wind instrument. The instrument specifically shown is a B-flat bass trumpet which includes a lead pipe 76 extending from a mouthpiece 78 to a first of the three valves 82a, 82b and 82c. The lead pipe 76 joins the valve 82a at that valve&#39;s primary surface aperture 28a defined by an end plate 22a. 
     A connecting loop 90 extends from a primary anchoring aperture 36a of a second end plate 34a to a primary anchoring aperture 36b defined by a second end plate 34b of the second valve 82b, see FIGS. 9 and 10. A second connecting loop 96 extends from a primary surface aperture 28b through a first end plate 22b of the second valve 82b to a primary surface aperture 28c in a first end plate 22c of the third valve 82c. From a primary anchoring aperture 36c through a second end plate 34c extends the instrument&#39;s main bore 104 which terminates at the instrument&#39;s bell 106. All three valves have slide loops 86a, 86b and 86c which connect their secondary surface apertures 30a, 30b and 30c to their secondary anchoring apertures 38a, 38b and 38c respectively. 
     OPERATION 
     As was previously mentioned, the slide plate 56 of each valve may be moved between two alternate positions by moving that valve&#39;s finger button 68. When the plate 56 is in the first or raised position, a direct path is formed through tube 42 between primary anchoring and surface apertures 36 and 28 so that the most direct possible path exists between the main bore and the lead pipe of the musical instrument. 
     The sound path is lengthened by moving the valve slide plate 56 to the lowered or second position so that a slide loop 86 is included in the circuit between the lead pipe and the main bore. This predetermined increase in the sound path length allows the instrument to produce a note of a lower pitch. When the finger button 68 is released, the spring 70 pushes the slide plate 56 back up against the upper stop 69 so that the instrument returns to its higher pitch. 
     The efficient operation of valves according to the present invention is not affected by reversing the direction in which air flows through the valves. Of the valves shown in FIGS. 8-11, only the second valve 82b employs the air flow direction shown in FIGS. 1 and 2. Valves 82a and 82c use reverse flow patterns. In other words, sound waves flow into valves 82a and 82c through their primary surface apertures 82a, 28c and leave those valves through their primary anchoring apertures 36a, 36c. 
     While I have shown and described preferred embodiments of my invention, it will be apparent to those skilled in the art that changes and modifications may be made without departing from my invention in its broader aspects. Therefore the scope of the present invention should only be determined by the following claims.