# Patent

## Title
Wind instrument and pipe structure thereof and a method of operating the wind instrument

## Abstract

A wind instrument is constituted of a mouthpiece and a pipe structure including tapered/straight pipes. The pipe structure is constituted of a blow member and a branch pipe. The branch pipe is branched into a main pipe and an auxiliary pipe, which are straight pipes having openings and connected together in a branch shape. The blow member is connected to a branch point of the branch pipe. The branch pipe simulates resonance characteristic of a tapered pipe having a predetermined length, a predetermined distance between the upper base and the vertex, and a predetermined sectional area of the upper base commensurate with the sectional area of the main pipe.

## Background
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to pipe structures of wind instruments.
The present application claims priority on Japanese Patent Application No. 2010-29311 (filing date: Feb. 12, 2010), the content of which is incorporated herein by reference.
2. Description of the Related Art
Various types of music synthesizer technologies simulating sound-producing mechanisms of acoustic instruments have been developed and disclosed in various documents such as Patent Document 1, namely Japanese Patent No. 2707913. Patent Document 1 discloses a music synthesizer device which simulates and reproduces resonance characteristics of a resonance pipe having a conical surface by way of a branch joint of two straight pipes.
FIGS. 1A-1C illustrate an approximation of resonance characteristics of a resonance pipe having a conical surface. FIG. 1A is a longitudinal sectional view of a resonance pipe 200 having a conical surface 204. The resonance pipe 200 is made of a hollow circular cone having a rotation axis X1 and a vertex V, which is truncated at a position of a distance R (measured from the vertex V) and at another position of a distance (R+L) in a direction indicated by an arrow D1. An opening 201 is formed at the position of the distance (R+L) from the vertex V, whilst another opening 202 is formed at the position of the distance R from the vertex V. S denotes a hollow area of the opening 202, and S2 denotes a hollow area of the opening 201. The area S differs from the area S2 in the resonance pipe 200. That is, the resonance pipe 200 is a tapered pipe having different sectional areas at opposite ends. In this connection, the rotation axis X1 refers to a rotation axis of a tapered pipe; the opening 201 having a large sectional area refers to a lower base; the opening 202 having a small sectional area refers to an upper base; a length L between the upper base and the lower base refers to a height; and a truncated length R refers to a distance between the vertex and the upper base.
An air column 203 inside the resonance pipe 200 resonates to sound input to the opening 202. Herein, c denotes a sound velocity of input sound; p denotes an air density of the air column 203; and k denotes the wave number of sound. In the case of a perfect reflection of sound at the opening 201 without considering attenuation due to friction of air inside the resonance pipe 200, an input acoustic impedance of the resonance pipe 200 viewed in the direction D1 is expressed by Equation (1).




  
    
      
        
          
            
              Z
              =
              
              ⁢
              
                
                  j
                  ·
                  ρ
                  ·
                  c
                  ·
                  k
                  ·
                  R
                  ·
                  
                    sin
                    ⁡
                    
                      (
                      
                        k
                        ·
                        L
                      
                      )
                    
                  
                
                
                  S
                  ⁢
                  
                    {
                    
                      
                        sin
                        ⁡
                        
                          (
                          
                            k
                            ·
                            L
                          
                          )
                        
                      
                      +
                      
                        k
                        ·
                        R
                        ·
                        
                          cos
                          ⁡
                          
                            (
                            
                              k
                              ·
                              L
                            
                            )
                          
                        
                      
                    
                    }
                  
                
              
            
          
        
        
          
            
              =
              
              ⁢
              
                1
                
                  
                    S
                    
                      j
                      ·
                      ρ
                      ·
                      c
                      ·
                      k
                      ·
                      R
                    
                  
                  +
                  
                    S
                    
                      j
                      ·
                      ρ
                      ·
                      c
                      ·
                      
                        tan
                        ⁡
                        
                          (
                          
                            k
                            ·
                            L
                          
                          )
                        
                      
                    
                  
                
              
            
          
        
      
    
    
      
        (
        1
        )
      
    
  




Upon substituting counterpart terms of Equation (1) with Equations (2) and (3), it is possible to produce Equation (4).




  
    
      
        
          Z
          R
        
        =
        
          
            j
            ·
            ρ
            ·
            c
            ·
            k
            ·
            R
          
          S
        
      
    
    
      
        (
        2
        )
      
    
  
  
    
      
        
          Z
          L
        
        =
        
          
            j
            ·
            ρ
            ·
            c
            ·
            
              tan
              ⁡
              
                (
                
                  k
                  ·
                  L
                
                )
              
            
          
          S
        
      
    
    
      
        (
        3
        )
      
    
  
  
    
      
        
          1
          Z
        
        =
        
          
            1
            
              Z
              R
            
          
          +
          
            1
            
              Z
              L
            
          
        
      
    
    
      
        (
        4
        )
      
    
  




Equation (4) shows that Z is produced via a parallel connection of ZR and ZL. Herein, ZR can be approximated to Equation (5) when kR is adequately small.




  
    
      
        
          Z
          R
        
        =
        
          
            
              j
              ·
              ρ
              ·
              c
              ·
              k
              ·
              R
            
            S
          
          ≈
          
            
              j
              ·
              ρ
              ·
              c
              ·
              
                tan
                ⁡
                
                  (
                  
                    k
                    ·
                    R
                  
                  )
                
              
            
            S
          
        
      
    
    
      
        (
        5
        )
      
    
  




In Equation (5), ZL denotes an acoustic impedance of a straight pipe having the length L at an open end having the sectional area S. When kR is adequately small, ZR denotes an acoustic impedance of another straight pipe having the length R at an open end having the sectional area S. As described above, an acoustic impedance of the resonance pipe 200 is approximated by an acoustic impedance of the joint structure constituted of two straight pipes. In the following description, two pipes may approximate each other when they have similar acoustic impedances.
FIG. 1B is a longitudinal sectional view of a pipe unit 210 which approximates the resonance pipe 200. The pipe unit 210 is made of a hollow cylindrical pipe having a rotation axis X2, which are vertically cut at opposite positions. The pipe unit 210 has two openings 211 and 216, which are distanced from each other and positioned opposite to each other. Both the openings 211 and 216 have the same hollow area S. The same sectional area S is secured at any position of the pipe unit 210 perpendicular to the rotation axis X2. That is, the pipe unit 210 is a straight pipe whose sectional area is not varied at any position in the length direction. In this connection, the rotation axis X2 refers to a rotation axis of a straight pipe, and the distance between opposite openings refers to the length of a straight pipe.
Specifically, the pipe unit 210 has a joint structure constituted of a straight pipe 214 having a length L and another straight pipe 215 having a length R. The straight pipe 214 has the opening 211, whilst the straight pipe 215 has the opening 216. The same sectional area is secured in both of the straight pipes 214 and 215. In actuality, it is difficult to produce a completely straight pipe whose sectional area is not varied at any position in the length direction. Practically, pipes having very small variations of sectional areas within an allowable range of significant digits of Approximate Equation (5) can be assumed to be straight pipes. The following description is made on an assumption that the sectional area of each straight pipe is not practically varied.
The straight pipe 214 embraces an air column 213 therein. The air column 213 has the length L along the rotation axis X2 of the straight pipe 214. For the sake of convenience, the length of an air column inside a straight pipe is deemed equivalent to the length along the rotation axis of the straight pipe. In addition, the length of an air column inside a tapered pipe is deemed equivalent to the length along the rotation axis of the tapered pipe. Sound is input to a joint portion of the pipe unit 210 (indicated by an arrow D2) between the straight pipes 214 and 215. Equation (6) is created by applying a positive constant H to Equation (5).




  
    
      
        
          Z
          R
        
        =
        
          
            
              j
              ·
              ρ
              ·
              c
              ·
              k
              ·
              R
            
            S
          
          =
          
            
              
                j
                ·
                ρ
                ·
                c
                ·
                H
                ·
                k
                ·
                R
              
              HS
            
            ≈
            
              
                j
                ·
                ρ
                ·
                c
                ·
                
                  tan
                  ⁡
                  
                    (
                    
                      k
                      ·
                      H
                      ·
                      R
                    
                    )
                  
                
              
              HS
            
          
        
      
    
    
      
        (
        6
        )
      
    
  




Herein, kR is multiplied by H (which is adequately smaller than “1”) and converted into kHR so as to produce tan(kHR), thus improving an approximation precision. When kHR is adequately small, Equation (6) shows an acoustic impedance of a straight pipe having an open end with a sectional area HS and a length HR. This indicates an approximation of the resonance pipe 200 by use of two straight pipes having different thicknesses. FIG. 1C is a longitudinal sectional view of a pipe unit 220 which approximates the resonance pipe 200. The pipe unit 220 has a joint structure constituting of a straight pipe 224 having a sectional area S and a length L and a straight pipe 225 having a sectional area HS and a length HR. An air column 223 having the length L is formed inside the straight pipe 224. Sound is input to a joint portion of the pipe unit 220 (indicated by an arrow D2) between the straight pipes 224 and 225.
FIG. 2 is a graph showing impedance curves of pipe units. Herein, IC210 denotes an impedance curve of the pipe unit 210, and IC220 denotes an impedance curve of the pipe unit 220. As shown in FIG. 2, the pipe units 210, 220 differ from each other in terms of a degree of harmony (or consonance) at peak frequencies of the impedance curves IC210, IC220. Herein, the pipe unit 220 deviates in consonance more than the pipe unit 210; hence, the pipe unit 220 may approximate the property of a tapered pipe. Patent Document 1 discloses an approximation of the resonance pipe 200 by use of a straight pipe applied to an acoustic instrument.
FIG. 3A shows an example of a wind instrument 100 in which a mouthpiece 300 is attached to an input portion of the resonance pipe 200 having the conical surface 204. A cork member is attached to the input portion of the resonance pipe 200. The input portion of the resonance pipe 200 is inserted into the mouthpiece 300 via the cork member.
FIG. 3B shows another example of a wind instrument having a branch joint, which may serve as a saxophone. This wind instrument approximates the pipe structure of the wind instrument 100 shown in FIG. 3A in which the resonance pipe 200 extends from the inside of the mouthpiece 300. Specifically, a straight pipe 231 is inserted into and mouthpiece 300 such that an opening 800 (which runs through the straight pipe 231 and the mouthpiece 300) is formed at a joint portion therebetween, wherein an attachment 801 is engaged with the opening 800. The attachment 801 implements the functionality of the foregoing straight pipe having a length HR and a sectional area HS. For the sake of convenience, the straight pipe 231 refers to a main pipe; the attachment 801 refers to an auxiliary pipe; and a branch pipe is interposed between the main pipe and the auxiliary pipe. The auxiliary pipe differs from sound holes (which will be discussed later) whose open ends are opened or closed to produce a desired pitch of sound. In contrast, an open end of the auxiliary pipe is normally opened to produce a desired pitch of sound.
Since the auxiliary pipe is disposed at the position of the mouthpiece, a small hole needs to be pierced through the mouthpiece to communicate with the auxiliary pipe. This mechanism leads to a positional fixation of the mouthpiece, which prevents a player from replacing the mouthpiece with a preferred mouthpiece.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a pipe structure of a wind instrument equipped with a branch pipe, which allows users to detachably attach desired mouthpieces to a resonance pipe.
A pipe structure of a wind instrument of the present invention includes a blow member which is connected with a mouthpiece, and a branch pipe which is branched into a main pipe and an auxiliary pipe. The blow member is connected to a branch point of the branch pipe. The main pipe or the auxiliary pipe is equipped with a pitch adjusting means which is able to produce a desired pitch in connection with an open end of the auxiliary pipe or a partial opening of the auxiliary pipe. The auxiliary pipe is equipped with an auxiliary pipe varying means which varies the length or amplitude of an air column resonating inside the auxiliary pipe. Thus, the branch pipe allows an air blown into the blow member to flow through the main pipe and the auxiliary pipe.
Preferably, the pitch adjusting means is configured of a sound hole, a bypass pipe or a slide pipe. The main pipe and the auxiliary pipe are configured of straight pipes having different lengths. The auxiliary pipe varying means includes an open/close hole formed on a side wall of the auxiliary pipe, so that the length of an air column resonating inside the auxiliary pipe is varied in response to an open/close operation of the open/close hole. In addition, the auxiliary pipe varying means includes a slide pipe attached to the auxiliary pipe, so that the length of an air column resonating inside the auxiliary pipe is varied in response to a sliding operation of the slide pipe. Furthermore, the auxiliary pipe varying means includes a bypass pipe attached to the auxiliary pipe, so that the length of an air column resonating inside the auxiliary pipe is varied in response to a pass-through which is switched over from an internal path of the auxiliary pipe to the bypass pipe.
The present invention allows a wind instrument having a branch pipe to suppress variations of tone colors.



BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, aspects, and embodiments of the present invention will be described in more detail with reference to the following drawings.
FIG. 1A is a longitudinal sectional view of a resonance pipe having a conical surface.
FIG. 1B is a longitudinal sectional view of a pipe unit having a joint structure constituted of two straight pipes both having the same sectional area.
FIG. 1C is a longitudinal sectional view of a pipe unit having a joint structure constituted of two straight pipes having different sectional areas.
FIG. 2 is a graph showing impedance curves representing the properties of pipe units shown in FIGS. 1B and 1C.
FIG. 3A is a longitudinal sectional view showing an example of a wind instrument using the conically-shaped resonance pipe shown in FIG. 1A together with a mouthpiece.
FIG. 3B is a longitudinal sectional view showing another example of a wind instrument using a straight pipe together with a mouthpiece.
FIG. 4 is a longitudinal sectional view of a wind instrument constituted of a tapered pipe unit and a mouthpiece.
FIG. 5 is a perspective view showing the exterior appearance of a pipe structure according to a first embodiment of the present invention.
FIG. 6A is a longitudinal sectional view of the pipe structure, which is constituted of a main pipe, an auxiliary pipe and a blow member.
FIG. 6B is a longitudinal sectional view of a wind instrument adopting the pipe structure of FIG. 6A, which is combined with a mouthpiece via a cork member.
FIG. 7 is a longitudinal sectional view of a wind instrument constituted of a mouthpiece and a pipe unit including tapered pipes having different taper ratios.
FIG. 8 is a longitudinal sectional view of a wind instrument having a pipe structure according to a second embodiment of the present invention.
FIG. 9 is a longitudinal sectional view of a wind instrument having a pipe structure according to a third embodiment of the present invention.
FIG. 10 is a longitudinal sectional view of a wind instrument having a pipe structure according to a fourth embodiment of the present invention.
FIG. 11 is a longitudinal sectional view of a wind instrument according to a first variation.
FIG. 12 is a longitudinal sectional view of a wind instrument adopting a lip-reed mouthpiece.
FIG. 13 is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a second variation.
FIG. 14 is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a third variation.
FIG. 15 is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a fourth variation.
FIG. 16A is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a fifth variation.
FIG. 16B is a longitudinal sectional view of the wind instrument shown in FIG. 16A, in which an auxiliary pipe is shortened in length.
FIG. 17 is a plan view of a wind instrument including a mouthpiece and a pipe structure according to a sixth variation.
FIG. 18A is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a seventh variation.
FIG. 18B is a longitudinal sectional view of the wind instrument shown in FIG. 18A, in which a main pipe is increased in length.
FIG. 19 is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to an eighth variation.
FIG. 20A is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a ninth variation.
FIG. 20B is a cross-sectional view showing a circular shape in which a main pipe and an auxiliary pipe juxtapose with each other.
FIG. 21A is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a tenth variation, wherein the pipe structure is connected to a bell.
FIG. 21B is a longitudinal sectional view of the wind instrument shown in FIG. 21A, wherein the pipe structure is connected to a tapered pipe.
FIG. 22 is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to an eleventh variation.
FIG. 23 is a longitudinal sectional view of a wind instrument including a mouthpiece, a pipe structure and a bell.
FIG. 24 is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a seventeenth variation, which is commensurate with the wind instrument shown in FIG. 23.
FIG. 25 is a longitudinal sectional view of a wind instrument including a mouthpiece, a bell and a pipe structure equipped with bypass members.
FIG. 26 is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to an eighteenth variation, which is commensurate with the wind instrument shown in FIG. 25.
FIG. 27A is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a twenty-first variation.
FIG. 27B is a cross-sectional view of the wind instrument taken along line C-C in FIG. 27A.
FIG. 28A is a longitudinal sectional view of a wind instrument including a mouthpiece and a pipe structure according to a twenty-second variation.
FIG. 28B is a cross-sectional view of the wind instrument taken along line D-D in FIG. 28A.
FIG. 29 is a graph showing acoustic characteristics of the wind instrument of the first embodiment shown in FIG. 5 in comparison with other wind instruments.
FIG. 30 is a graph showing acoustic characteristics of the wind instrument of the first variation shown in FIG. 11 in comparison with other wind instruments.
FIG. 31 is a graph showing acoustic characteristics of the wind instrument of the twenty-first variation shown in FIGS. 27A and 27B in comparison with other wind instruments.
FIG. 32 is a graph showing acoustic characteristics of the wind instrument of the twenty-second variation shown in FIGS. 28A and 28B in comparison with other wind instruments.



DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in further detail by way of examples with reference to the accompanying drawings.
1. First Embodiment
FIG. 4 illustrates a wind instrument 100a including a tapered pipe 122a. The overall shape of the wind instrument 100a is identical to that of the wind instrument 100 shown in FIG. 3A, whereas for the sake of illustration, the tapered pipe 120a is slightly modified in dimensions and divided into two sections assigned with new reference numerals. That is, reference numeral S2a corresponds to S in FIG. 3A; the total length of Ra and La is identical to the total length of R and L in FIG. 3A. FIG. 4 is a longitudinal sectional view of the wind instrument 10a which is constituted of a pipe unit 120a and a mouthpiece 130a. The pipe unit 120a is composed of a plastic or a metal such as a brass. The pipe unit 120a is constituted of tapered pipes 122a, 124a, wherein the tapered pipe 124a is formed continuously with the tapered pipe 122a. Herein, a taper ratio TR denotes an expanse per unit length along the rotation axis of a tapered shape (or a conical shape). The taper ratio TR serves as a measure representing a degree of expanse of a conical shape. Both the tapered pipes 122a, 124a have the same taper ratio TR. The tapered pipe 122a has a length La and a sectional area Sa at the upper base, wherein Ra denotes a length from the upper base to the vertex of the tapered pipe 122a. The tapered pipe 124a has a sectional area Sa at the lower base and a sectional area S2a at the upper base. The tapered pipe 124a is inserted into the mouthpiece 130a such that the upper base and its associate portion thereof are covered with the mouthpiece 130a. 
FIG. 5 shows an exterior appearance of a pipe structure 20a according to a first embodiment of the present invention. In FIG. 5 and its associate drawings, constituent parts are modified in dimensions in an easy-to-comprehend manner so that the dimensions thereof differ from dimensions of actual products. For the sake of clarification, sectional areas are illustrated with net-like paints. The pipe structure 20a is composed of a plastic or a metal such as a brass. The pipe structure 20a is constituted of a main pipe 22a (i.e. a straight pipe which is linearly extended in an axial direction), an auxiliary pipe 23a (i.e. a straight pipe which is linearly extended in an axial direction), and a blow member 24a (i.e. a tapered pipe). The main pipe 22a and the auxiliary pipe 23a are interconnected to form a branch pipe 21a (which is branched into the main pipe 22a and the auxiliary pipe 23a).
FIGS. 6A and 6B illustrate a wind instrument 10a equipped with the pipe structure 20a of the first embodiment, wherein parts identical to those shown in FIG. 5 are designated by the same reference numerals; hence, the description thereof will be omitted. FIG. 6A is a longitudinal sectional view of the pipe structure 20a taken along line A-A in FIG. 5. The blow member 24a has a tapered shape having upper and lower bases, wherein a hollow joint 24a1 is formed at the lower base whilst an opening 24a2 is formed at the upper base. The hollow joint 24a1 of the blow member 24 has an internal sectional area of Sa whilst opening 24a2 has an internal sectional area of S2a where Sa is greater than S2a. 
The main pipe 22a has an opening 22a1 at the terminal end thereof, whilst a hollow joint 22a2 is formed at the opposite end. The main pipe 22a is connected to the blow member 24a with the hollow joint 22a2. The hollow joint 22a2 of the main pipe 22a has an internal sectional area of Sa. The main pipe 22a is connected to the auxiliary pipe 23a at the side face of the hollow joint 22a2. The auxiliary pipe 23a is connected to the main pipe 22a with the lower end thereof, whilst an opening is formed at the upper end. The internal space of the main pipe 22a is interconnected with the internal space of the auxiliary pipe 23a. That is, the hollow joint 22a2 of the main pipe 22a is disposed at a branch point at which the branch pipe 21a is branched into the main pipe 22a and the auxiliary pipe 23a. The branch pipe 21a is connected to the blow member 24 such that the hollow joint 22a2 is coupled with the hollow joint 24a1. According to this structure, a gas (e.g. an air) blown into a single blow member 24a flows into the main pipe 22a and the auxiliary pipe 23a. 
FIG. 6B is a longitudinal sectional view of a wind instrument 10a including the pipe structure 20a shown in FIG. 6A. The wind instrument 10a is constituted of the pipe structure 20a and a mouthpiece 30a. The mouthpiece 30a is a part of the wind instrument 10a which allows a player to blow his/her breath into the pipe structure 20a while placing his/her lips thereon. The mouthpiece 30a is composed of ebonite or the like. The mouthpiece 30a is equipped with a flake-shaped reed 31a composed of a cane or the like. The mouthpiece 30a corresponds to conventional mouthpieces normally applied to acoustic instrument such as woodwind instruments. The mouthpiece 30a transmits air vibration, which occurs when a player vibrates the reed 31a with his/her breath, to the pipe structure 20a. 
The blow member 24a is inserted into the mouthpiece 30a such that the opening 24a2 is covered with the mouthpiece 30a. The blow member 24a has a detachable-connect portion 24a3 which allows the mouthpiece 30a to attach thereto or detach therefrom. A cork member 40a is attached to the exterior of the blow member 24a. When the mouthpiece 30a is engaged with the blow member 24a, the cork member 40 is covered with the mouthpiece 30a. The mouthpiece 30a is fixed to the blow member 24a at a desired position while the insertion length of the mouthpiece 30a is adjusted to finely adjust pitches of sound produced by the wind instrument 10a. The mouthpiece 30a can be detached from the blow member 24a via the cork member 40a. Since the detachable-connect portion 24a3 is positioned differently from the auxiliary pie 23a, the wind instrument 10a does not need to form an opening in the mouthpiece 30a, which is thus different from the foregoing mouthpiece 300 shown in FIGS. 3A and 3B. For this reason, the detachable-connect portion 24a3 of the blow member 24a is able to detachably attach thereto conventional mouthpieces used in saxophones.
La denotes a distance ranged from the opening 22a1 of the main pipe 22a to a center line Da of the auxiliary pipe 23a. Only one terminal end of the main pipe 22a is opened by way of the opening 22a1. The auxiliary pipe 23a has a length H×Ra and a sectional area H×Sa. That is, the branch pipe 21a approximates an imaginable tapered pipe with the distance Ra from the upper base to the vertex and the distance La from the upper base to the lower base. In this connection, H denotes a positive constant smaller than “1” in Equation (6).
FIG. 29 illustrates acoustic characteristics of the wind instrument 10a of the first embodiment. In FIG. 29A, A denotes an input impedance curve representative of the wind instrument 100a of FIG. 4 in which the mouthpiece 130a is connected to conical pipe (i.e. the pipe unit 120a); B denotes an input impedance curve representative of the wind instrument 100a of FIG. 4 approximating the structure of FIG. 3B in which the auxiliary pipe (i.e. the attachment 801) is branched inside the mouthpiece 300, in which the sectional area S of the main pipe (i.e. the straight pipe 231) is equal to the sectional area S2a of the upper base of the conical pipe (i.e. the pipe unit 120a) shown in FIG. 4 and in which all the sound holes (not shown) are closed; and C denotes an input impedance curve representative of the wind instrument 10a of the first embodiment of FIG. 6B in which the branch pipe 21a approximates the blow member 24a and onwards and in which all the sound holes (i.e. sound holes 25a) are closed. FIG. 29 shows that compared to the input impedance curve B of the conventional branch-type wind instrument in which the auxiliary pipe is branched inside the mouthpiece, the input impedance curve C of the first embodiment is closer to the input impedance curve A of the wind instrument 100a of FIG. 4 particularly in terms of the peak value of a low-frequency input impedance. This proves that the present embodiment has good acoustic characteristics.
As described above, the branch pipe 21a approximates the tapered pipe 122a; hence, the tone color of the wind instrument 10a approximates the tone color of the wind instrument 100a. For the sake of clarification, two wind instruments approximate to each other when they are able to produce similar tone colors. In this connection, the branch pipe 21a is not necessarily limited to the foregoing shape approximating the tapered pipe 122a. 
Referring back to FIG. 6B, the main pipe 22a has seven sound hones 25a (namely, 25a1, 25a2, 25a3, 25a4, 25a5, 25a6 and 25a7) which are formed on the side wall and aligned from the opening 22a1. A player can preferably open or close the sound holes 25a with his/her fingers. The length of an air column resonating in the main pipe 22a is varied in response to each combination of sound holes 25a being opened or closed, thus producing a desired pitch. These sound holes 25a may collectively serve as a pitch adjusting means installed in a pipe structure of a wind instrument. When a player plays the wind instrument 10a while opening/closing the sound holes 25a, the wavelength of sound resonating in the branch pipe 21a is varied so that sound of the wind instrument 10a is varied in pitches.
The wind instrument 10a is designed to produce sound with preset pitches corresponding to combinations sound holes 25a being opened/closed. When a player plays the wind instrument 10a with the sound holes 25a4-25a7 being closed while the sound holes 25a1-25a3 being opened, for example, the wind instrument 10a produces sound F. This state is expressed such that the wind instrument 10a is played with sound holes being opened up to 25a3, whereby the preset pitch of the sound hole 25a3 is set to F. That is, sounds D, E, F, G, A, B and C are preset to the sound holes 25a1, 25a2, 25a3, 25a4, 25a5, 25a6 and 25a7 respectively. The sound holes 25a are formed at predetermined positions with predetermined sizes to produce respective preset pitches on condition that the upper end of the auxiliary pipe 23a is opened. These preset pitches are illustrative and not restrictive; hence, other pitches can be set to the sound holes 25a; alternatively, the present pitches can be assigned to other combinations of the sound holes 25a being opened or closed. The number of the sound holes 25a formed in the main pipe 22a, their arrangements and sizes can be determined in light of sounds and registers of wind instruments.
2. Second Embodiment
FIG. 7 is a longitudinal sectional view of a wind instrument 100b including tapered pipes having different taper ratios. The wind instrument 100b is constituted of a pipe unit 120b and a mouthpiece 130b. The pipe unit 120b is composed of a plastic or a metal such as a brass. The pipe unit 120b is constituted of tapered pipes 122b and 124b, which are interconnected. The tapered pipe 122b has a tapered shape having upper and lower bases with a length Lb, wherein Sb denotes a sectional area at the upper base, and Rb denotes a length ranging from the upper base to the vertex. The tapered pipe 124b has a tapered shape having upper and lower bases with a length L2b, wherein Sb denotes a sectional area at the lower base; S2b denotes a sectional area at the upper base; and R2b denotes a length ranging from the upper base to the vertex. The tapered pipe 124b is partially inserted into the mouthpiece 130b such that the upper base and its associate portion are covered with the mouthpiece 130b. 
The tapered pipes 122b and 124b differ from each other in terms of an expanse of a tapered shape (or a conical shape). Specifically, the taper ratio of the tapered pipe 122b is smaller than the taper ratio of the tapered pipe 124b. The taper ratio of the tapered pipe 124b is calculated by dividing the diameter of the upper base by the length R2b (ranging from the upper base to the vertex). The taper ratio of the tapered pipe 122b is calculated by dividing the diameter of the upper base by the length Rb (ranging from the upper base to the vertex).
FIG. 8 illustrates a pipe structure 20b of a wind instrument 10b according to a second embodiment of the present invention, wherein parts equivalent to those of the wind instrument 10a shown in FIG. 6B are designated by counterpart reference numbers suffixed with “b” instead of “a”. The following description refers to only the differences between the wind instruments 10a and 10b while omitting the similarity therebetween. FIG. 8 is a longitudinal sectional view of the wind instrument 10b, which is constituted of the pipe structure 20b (i.e. a joint structure of a tapered pipe and a straight pipe) and a mouthpiece 30b (corresponding to the mouthpiece 30a). The pipe structure 20b is constituted of a branch pipe 21b (corresponding to the branch pipe 21a) and a blow member 24b. The branch pipe 21b is constituted of a main pipe 22b and an auxiliary pipe 23b. 
The blow member 24b has a tapered shape having upper and lower bases, wherein a hollow joint 24b1 is formed at the lower base whilst an opening 24b2 is formed at the upper base. The hollow joint 24b1 has a sectional area Sb whilst the opening 24b2 has a sectional area S2b. The sectional Sb is larger than the sectional area S2b; hence, the radius of the hollow joint 24b1 is larger than the radius of the opening 24b2. The blow member 24b is connected to the branch pipe 21b with the hollow joint 24b1 having the large sectional area Sb. The mouthpiece 30b is attached to the blow member 24b to cover the opening 24b2 having the small sectional area 24b2. A cork member 40b is inserted into a gap between the blow member 24b and the mouthpiece 30b. The mouthpiece 30b can be attached to or detached from the blow member 24b. The blow member 24b has a detachable-connect portion 24b3 which the mouthpiece 30b is detachably attached to. This constitution allows air blown into a single blow member 24b to flow through the main pipe 22b and the auxiliary pipe 23b. 
The wind instrument 10b includes the “tapered” blow member 24b, which provides a player with a blowing sensation, similar to that of an acoustic wind instrument having a tapered blow member, rather than another wind instrument having a “straight” blow member. By adjusting the length of the blow member 24b, it is possible to adjust a sensation of resistance which a player may feel when blowing his/her breath into the pipe structure 20b. The wind instrument 10b can be modified using tapered pipes having different taper ratios as follows.
In FIG. 8, Lb denotes a length ranging from the opening 22b1 of the main pipe 22b to a center line Db of the auxiliary pipe 23b. Only one terminal end of the main pipe 22b is opened by way of the opening 22b1, wherein the auxiliary pipe 23b has a length of H×Rb and a sectional area of H×Sb. In this case, the branch pipe 21b can be approximated to an imaginable tapered pipe with the length Rb ranging from the upper base to the vertex, the sectional area Sb at the upper base, and the length Lb ranging from the upper base to the lower base. Herein, H denotes a positive constant in Equation (6). The blow member 24b has the same shape as the tapered pipe 124b. The wind instrument 10b having this constitution is able to reproduce sound of the wind instrument 100b including tapered pipes of different taper ratios. In this connection, the branch pipe 21b is not necessarily limited to an approximate shape of the tapered pipe 122b. 
3. Third Embodiment
FIG. 9 illustrates a pipe structure 20c of a wind instrument 10c according to a third embodiment of the present invention. FIG. 9 is a longitudinal sectional view of the wind instrument 10c, wherein parts identical to those of the wind instrument 10a will be designated by the same reference numerals; hence, the description thereof will be omitted. The wind instrument 10c differs from the wind instrument 10a in terms of some parts, dimensions and quantity; hence, the following description will be made with respect to only the differences therebetween while omitting the counterpart components therebetween by use of the same reference numerals suffixed with “c” instead of “a”. An octave hole 26c is formed in proximity to a hollow joint 22c2 of a main pipe 22c in the wind instrument 10c. When a player plays the wind instrument 10c while closing the octave hole 26c, standing waves whose wavelengths are consummate with the preset pitches of the sound holes 25a occur inside the pipe structure 20c. When a player plays the wind instrument 10c while opening the octave hole 26c, standing waves are affected and converted into other standing waves with half the wavelengths, producing sounds whose pitches are one-octave higher than the preset pitches of the sound holes 25a. 
4. Fourth Embodiment
FIG. 10 illustrates a pipe structure 20d of a wind instrument according to a fourth embodiment of the present invention. FIG. 10 is a longitudinal sectional view of the wind instrument 10d, wherein parts identical to those of the wind instrument 10a are designated by the same reference numerals; hence, the description thereof will be omitted. The wind instrument 10d differs from the wind instrument 10a in terms of the shape, dimensions and quantity; hence, the following description will be given with respect to only the differences therebetween while omitting the counterpart components therebetween by use of the same reference numerals suffixed with “d” instead of “a”. The pipe structure 20d is constituted of the main pipe 22a and the blow member 24a as well as an auxiliary pipe 23d. An octave hole 26d is formed in proximity to the hollow joint 22a2 of the main pipe 22a. The auxiliary pipe 23d is a straight pipe in which the lower end thereof is connected to the main pipe 22a while the upper end is opened, so that the internal space of the main pipe 22a is interconnected to the internal space of the auxiliary pipe 23d. An open/close hole 27d, which is opened or closed upon a player's operation, is formed on the side wall of the auxiliary pipe 23d. The open/close hole 27d is positioned at a height Ld above the lower end of the auxiliary pipe 23d connected to the main pipe 22a. Herein, Lt denotes an interval of distance (namely, a sound-hole distance) from a center line Dd of the auxiliary pipe 23d to each sound hole 25a. For instance, Lt7 denotes a sound-hole distance of the sound hole 25a7 from the center line Dd. The sound-hole distance Lt represents the length of an air column resonating inside the main pipe 22a. 
When a player plays the wind instrument 10d while opening the sound hole(s) 25a, the pipe structure 20d undergoes an intense state or a weak state in an even-number mode of resonance. For instance, the sound holes 25a1 through 25a5 cause the pipe structure 20d to undergo the intense state in an even-number mode of resonance. In an open state of the octave hole 26d, it is possible to easily produce sound one octave higher than the preset pitches of the sound holes 25a1-25a5. In contrast, the sound holes 25a6 and 25a7 cause the pipe structure 20d to undergo the weak state in an even-number mode of resonance because the sound-hole distances Lt thereof are shorter than the length of the auxiliary pipe 23d. In addition, the second-mode resonance frequency becomes higher than twice the first-mode resonance frequency which is commensurate with a register one octave higher than the first-mode resonance frequency. For this reason, when a player plays the wind instrument 10d while opening the sound holes up to the sound hole 25a6 or 25a7 in the open state of the octave hole 26d, it is difficult to produce sound one octave higher than the preset pitches. In addition, the sound in this state unexpectedly increases in pitch so as to cause a difference of tone color compared to sound in another register.
In order to produce sound one octave higher than the preset pitch of the sound hole 25a6 or 25a7, a player needs to play the wind instrument 10d in the open state of the octave hole 26d and the open/close hole 27d. Compared to the performance of the wind instrument 10d in the close state of the open/close hole 27d, it is possible to reduce the length of an air column resonating in the auxiliary pipe 23d in the open state of the open/close hole 27d. Thus, it is possible to change the length of an air column resonating in the auxiliary pipe 23d in response to the open/close state of the open/close hole 27d. In this connection, the open/close hole 27d may serve as an auxiliary pipe varying means. At this time, the auxiliary pipe 23d functions as an auxiliary pipe having the fixed length Ld, which may be longer than the sound-hole distance Lt, thus intensifying the even-number mode of resonance in the pipe structure 20d. Thus, the wind instrument 10d is able to easily produce sound one octave higher than all the preset pitches of the sound holes 25a in the overall register; hence, it is possible to produce sound with preferable pitches and tone colors.
When a player plays the wind instrument 10d in the close state of the octave hole 26d, the wind instrument 10d produces sound with the preset pitches of the sound holes 25a. In this state, the tone color is varied in response to the open/close state of the open/close hole 27d. This constitution allows a player to change pitches and/or tone colors during performance of the wind instrument 10d in progress by operating the open/close hole 27d of the auxiliary pipe 23d. The wind instrument 10d is equipped with an indicator means indicating production of sound one octave higher than the preset pitches. In addition, the wind instrument 10d can be further equipped with an open/close mechanism for opening/closing one of or both of the octave hole 26d and the open/close hole 27d in response to the content of the indicator means and the open/close state of the sound holes 25a. In this connection, it is possible to form a plurality of open/close holes 27d in the wind instrument 10d, whereby a player is able to adjust the length of an air column resonating in the auxiliary pipe 23d by opening/closing the open/close holes 27d in response to the open/close states of the sound holes 25a. Alternatively, the same effect can be achieved by opening at least one of the open/close holes 27d, which are aligned along the auxiliary pipe 23d, while closing the terminal end of the auxiliary pipe 23d. It is preferable that a partial opening be formed in the auxiliary pipe 23d or that the terminal end be opened.
5. Variations
The present invention is not necessarily limited to the foregoing embodiments, which can be further modified in various ways.
(1) First Variation
The first, third and fourth embodiments are designed to use the “tapered” blow member 24a, whereas they can be modified to use a “straight” blow member. In this case, all the main pipe, auxiliary pipe and blow member are configured of straight pipes. This wind instrument employing straight pipes is designed to approximate the property of the wind instrument 100a including the tapered pipes 122a and 124a shown in FIG. 4.
FIG. 11 is a longitudinal sectional view of a wind instrument 10e according to a first variation, wherein parts identical to those of the wind instrument 10a are designated by the same reference numerals suffixed with “e” instead of “a”; hence, the description thereof will be omitted. The following description refers to only the difference between the wind instruments 10a and 10e while omitting the similarity therebetween. The wind instrument 10e is constituted of a pipe structure 20e and a mouthpiece 30e, wherein the pipe structure 20e includes the main pipe 22a, the auxiliary pipe 23a, and a blow member 24e, all of which are straight pipes. The pipe structure 20e is composed of a metal such as a brass. The pipe structure 20e includes a “straight” blow member 24e, the exterior surface of which is covered with a cork member 40e. The blow member 24e is inserted into the mouthpiece 30e via the cork member 40e. The blow member 24e has an opening 24e2 in the side of the mouthpiece 30e. The mouthpiece 30e is detachably attached to the blow member 24e on which exterior surface the cork member 40e is adhered. The mouthpiece 30e is attached to or detached from a detachable-connect portion 24e3 of the blow member 24e. In this connection, the mouthpiece 30e can be fixed to the pipe structure 20e. 
A hollow joint 24e1 having a sectional area Sa is formed opposite to the opening 24e2 of the blow member 24e. The blow member 24e is connected to the branch pipe 21a such that the hollow joint 24e1 is coupled with the hollow joint 22a2 of the main pipe 22. According to this constitution, the wind instrument 10e approximates an imaginary wind instrument in which the blow member 24e is connected to the tapered pipe 122a shown in FIG. 4. As blow members, wind instruments can adopt any types of pipes such as tapered pipes and straight pipes. In this connection, blow members can be modified such that certain portions thereof serve as tapered pipes while other portions serve as straight pipes.
FIG. 30 illustrates acoustic characteristics of the wind instrument 10e of the first variation. In FIG. 30, D denotes an input impedance curve of the wind instrument 10a of the first embodiment shown in FIG. 6B in which the branch pipe 21a approximates the blow member 24a and onwards and in which all the sound holes 25a are closed; and E denotes an input impedance curve of the wind instrument 10e of the first variation shown in FIG. 11 in which the blow member 24a is replaced with a straight pipe (i.e. the blow member 24e) and in which all the sound holes are closed.
Through comparison between the input impedance curves D and E, even though the wind instrument 10e of the first variation has a simple constitution including the straight blow member 24e, the wind instrument 10e has the same input impedance curve as the wind instrument 10a; hence, the wind instrument 10e has good acoustic characteristics as the wind instrument 10a. That is, the first variation is able to satisfy preferable acoustic characteristics while simplifying the manufacturing process because of the straight shape of the blow member 24e including the detachable-connect portion 24e3.
(2) Second Variation
The foregoing embodiments adopt a single-reed mouthpiece (i.e. a mouthpiece using a single flake-shaped reed) in wind instruments; however, the present invention is applicable to wind instruments adopting double-reed mouthpieces or lip-reed mouthpieces.
FIG. 12 illustrates a wind instrument adopting a lip-reed mouthpiece. FIG. 12 is a longitudinal sectional view of a wind instrument 100f, which is constituted of a pipe unit 120f, a mouthpiece 130f and a mouthpiece attachment 132f. The mouthpiece attachment 132f is adhered to the pipe unit 120f. All the pipe unit 120f, the mouthpiece 130f and the mouthpiece attachment 132f are composed of a metal such as a brass. The pipe unit 120f is constituted of tapered pipes 122f and 124f, which are continuously connected with each other. The tapered pipes 122f and 124f are portions of the pipe unit 120f. The tapered pipe 122f has a tapered shape having upper and lower bases with a length Lf, wherein Sf denote a sectional area of the upper base, and Rf denotes the length ranging from the upper base to the vertex. The tapered pipe 124f has a tapered shape having upper and lower bases with a length L2f, wherein S2f denotes a sectional area of the upper base, Sf denotes a sectional area of the lower base, and R2f denotes a length ranging from the upper base to the vertex. In this illustration, the taper ratio of the tapered pipe 122f is larger than the taper ratio of the tapered pipe 124f. 
FIG. 13 illustrates a wind instrument 10f including a pipe structure 20f according to a second variation, wherein parts equivalent to those of the wind instrument 100f are designated by the two-digit reference numerals precluding hundredth places from three-digit reference numerals shown in FIG. 12; hence, the description thereof will be omitted. FIG. 13 is a longitudinal sectional view of the wind instrument 10f, which is constituted of the pipe structure 20f (including a straight pipe and a tapered pipe) and a mouthpiece 30f. The pipe unit 20f is composed of a metal such as a brass. The pipe unit 20f includes a tapered blow member 24f including a hollow joint 24f1 (disposed at the lower base) and an opening 24f2 (disposed at the upper base), wherein Sf denotes a sectional area of the hollow joint 24f1, and S2f denotes a sectional area of the opening 24f2 (where Sf>S2f).
The blow member 24f has a detachable-connect portion 24f3 at the opening 24f2, allowing the mouthpiece 30f to be detachably attached thereto. A mouthpiece attachment 32f is attached to the detachable-connect portion 24f3 of the blow member 24f. The mouthpiece 30f is engaged with the mouthpiece attachment 32f and thereby fixed in position. The mouthpiece 30f is a component of a wind instrument which comes in contact with player's lips and which player's breath is blown into. The mouthpiece 30f is composed of a brass or the like. A player vibrates his/her lips placed on the mouthpiece 30f so as to cause an air vibration which serves as a sound source of the wind instrument 10f. The mouthpiece 30f inputs an air vibration into the blow member 24f. Since the detachable-connect portion 24f3 of the blow member 24f is positioned differently from an auxiliary pipe 23f, the wind instrument 10f does not need to form an opening in the mouthpiece 30f, which is thus different from the mouthpiece 300 shown in FIGS. 3A and 3B. That is, it is possible to detachably attach conventional mouthpieces adopted in trumpets to the detachable-connect portion 24f3 of the blow member 24f. 
The pipe structure 20f includes a branch pipe 21f constituted of the main pipe 22f and the auxiliary pipe 23f, both of which are straight pipes. The main pipe 22f has an opening 22f1 at one end thereof, whilst a hollow joint 22f2 is formed at the other end. The main pipe 22f is connected to the auxiliary pipe 23f with the side portion of the hollow joint 22f2. The lower end of the auxiliary pipe 23f is connected to the main pipe 22f, whilst the upper end is opened. The internal space of the main pipe 22f is interconnected to the internal space of the auxiliary pipe 23f. That is, the hollow joint 22f2 is disposed at a branch point at which the branch pipe 21f is branched into the main pipe 22f and the auxiliary pipe 23f. The branch pipe 21f is connected to the blow member 24f such that the hollow joint 22f2 is coupled with the hollow joint 24f1. Herein, Lf denotes a distance ranging from the opening 22f1 of the main pipe 22f to a center line Df of the auxiliary pipe 23f. In order to approximate the tapered pipe 122f with the length Rf ranging from the upper base to the vertex and the sectional area Sf at the upper base (see FIG. 12), the auxiliary pipe 23f of the branch pipe 21f is designed with a length of H×Rf and a cross section of H×Sf, where H denotes a positive constant in Equation (6).
According to this constitution, the wind instrument 10f is able to produce preferable sound with the tone color approximating the wind instrument 100f including a lip-reed mouthpiece and a resonance pipe continuously connecting two conical shapes of different taper ratios. The second variation is designed to use the tapered blow member 24f, which can be replaced with a straight blow member. The branch pipe 21f of the second variation is constituted of the main pipe 22f and the auxiliary pipe 23f, one of which or both of which can be configured of tapered pipes.
(3) Third Variation
In the wind instrument 10c of the third embodiment shown in FIG. 9, the octave hole 26c is formed in the main pipe 22c; but this is not a restriction. The octave hole 26c can be formed at another position. When the sound-hole distance Lt7 is shorter than the length of the auxiliary pipe 23a, for example, a node of a second-mode standing wave emerges inside the auxiliary pipe 23a. In this case, it is impossible to produce sound one octave higher than the preset pitch of the sound hole 25a7 in the open state of the octave hole 26c disposed in proximity to the hollow joint 22c2. To solve this drawback, it is possible to form an octave hole in the auxiliary pipe 23a. Alternatively, it is possible to form octave holes in both the main pipe 22c and the auxiliary pipe 23a. 
FIG. 14 illustrates a wind instrument 10g having a pipe structure 20g according to a third variation. FIG. 14 is a longitudinal sectional view of the wind instrument 10g which is constituted of the main pipe 22a, the blow member 24a and the mouthpiece 30a, wherein parts identical to those of the wind instrument 10c shown in FIG. 9 are designated by the same reference numerals. In the wind instrument 10g, an octave hole 26g is formed on the side wall of the blow member 24a connected with the main pipe 22a. In addition, a secondary octave hole 26g2 is formed on the side wall of an auxiliary pipe 23g (which replaces the auxiliary pipe 23a shown in FIG. 9). When a player plays the wind instrument 10g in the close state of the octave holes 26g and 26g2, a standing wave whose wavelength is commensurate with the preset pitches of the sound holes 25a occurs inside the pipe structure 20g. When a player plays the wind instrument 10g with the octave hole 26g being opened while the secondary octave holes 26g2 being closed, the wind instrument 10g produces sound one octave higher than the preset pitches of the sound holes 25a1-25a7. In contrast, when a player plays the wind instrument 10g with the octave hole 26g being closed and the octave hole 26g2 being opened, the wind instrument 10g produces sound one octave higher than the preset pitch of the sound hole 25a7. According to this structure, even when the sound-hole distance is shorter than the length of the auxiliary pipe 23g, the wind instrument 10g is able to produce sound one octave higher than the preset pitch with the octave holes 26g and 26g2 being properly operated.
(4) Fourth Variation
The octave hole 26c is formed in the main pipe 22c in the wind instrument 10c of the third embodiment, whilst the octave holes 26g and 26g2 are formed in the main pipe 22a and the auxiliary pipe 23g in the wind instrument 10g of the third variation. Octave holes can be formed at other positions of the pipe structure 20c/20g. When the sound-hole distance Lt7 is shorter than the length of the blow member 24a, for example, a node of a second-mode standing wave occurs inside the blow member 24a. In this case, the wind instrument 10c is unable to produce the preset pitch C of the sound hole 25a7 in the open state of the octave hole 26c disposed in proximate to the hollow joint 22c2 of the main pipe 22c. To solve this drawback, it is possible to form an octave hole in the blow member 24a. Alternatively, octave holes can be formed in the main pipe 22c and the blow member 24a; or octave holes can be formed in the main pipe 22c, the auxiliary pipe 23a and the blow member 24a. 
FIG. 15 illustrates a wind instrument 10h having a pipe structure 20h according to a fourth variation. FIG. 15 is a longitudinal sectional view of the wind instrument 10h, which is constituted of the pipe structure 20h (including a tapered pipe and a straight pipe) and a mouthpiece 30h. The pipe structure 20h is composed of a metal such as a brass. The pipe structure 20h includes a blow member 24h which is a tapered pipe. The blow member 24h has a hollow joint 24h1 at the lower base and an opening 24h2 at the upper base, wherein Sh denotes a sectional area of the hollow joint 24h1, and S2h denotes a sectional area of the opening 24h2 (where Sh>S2h). The radius of the hollow joint 24h1 is larger than the radius of the opening 24h2. The mouthpiece 30h is attached to the blow member 24h at the opening 24h2 having a small radius.
A cork member 40h is inserted into a gap between the blow member 24h and the mouthpiece 30h. The mouthpiece 30h and the cork member 40h are detachably attached to the blow member 24h. The blow member 24h has a detachable-connect portion 24h3, which allows the mouthpiece 30h to be attached thereto. In this connection, the mouthpiece 30h can be fixed to the pipe structure 20h. The sectional area Sh of the lower base of the blow member 24h (which commensurate with the cross section of the main pipe 22h) is larger than the sectional area Sa of the lower base of the blow member 24a adapted to the wind instrument 10a shown in FIG. 6A. Through comparison between the wind instrument 10a of FIG. 6A and the wind instrument 10h of FIG. 15, the blow member 24h is larger than the blow member 24a; the mouthpiece 30h is larger than the mouthpiece 30a; and the distance between the hollow joint 24h1 and the opening 24h2 of the blow member 24 is larger than the distance between the hollow joint 24a1 and the opening 24a2 of the blow member 24a. That is, the distance between the tip end of the mouthpiece 30h (which is apart from the blow member 24h) and the hollow joint 24h1 of the blow member 24h is larger than the distance between the tip end of the mouthpiece 30a and the hollow joint 24a1. An octave hole 26h is formed in the blow member 24h in proximity to the hollow joint 24h1 rather than the detachable-connect portion 24h3.
The pipe structure 20h has a branch pipe 21h which is branched into a main pipe 22h and an auxiliary pipe 23h, both of which are straight pipes. The main pipe 22h has an opening 22h1 at one end thereof, whilst a hollow joint 22h2 is formed at the other end. The main pipe 22h is connected to the auxiliary pipe 23h with the side portion of the hollow joint 22h2. The lower end of the auxiliary pipe 23h is connected to the main pipe 22h, whilst the upper end is opened. The internal space of the main pipe 22h is interconnected to the internal space of the auxiliary pipe 23h. That is, the hollow joint 22h2 of the main pipe 22h is disposed at a branch point at which the branch pipe 21h is branched into the main pipe 22h and the auxiliary pipe 23h. The branch pipe 21h is connected to the blow member 24h such that the hollow joint 22h2 is coupled with the hollow joint 24h1. Herein, Lh denotes a distance ranging from the opening 22h1 of the main pipe 22h to a center line Dh of the auxiliary pipe 23h. In order to approximate an imaginary tapered pipe with a length Rh ranging from the upper base to the vertex and a sectional area Sh of the upper base, the auxiliary pipe 23h of the branch pipe 21h is formed with a length of H×Rh and a sectional area of H×Sh, wherein H denotes a positive constant in Equation (6).
According to this constitution, when a player plays the wind instrument 10h in the open state of an octave hole 26h which is formed on the side wall of the blow member 24h, the wind instrument 10h is able to produce sound one octave higher than preset pitches of sound holes 25h (i.e. sound holes 25h1 through 25h7). As described above, an octave hole needs to be disposed at a position commensurate with the length of an air column resonating in a main pipe, an auxiliary pipe or a blow member in a wind instrument. In addition, when the length of a resonating air column, which is varied in response to the sound holes 25h (or a pitch adjusting means), is shorter than the predetermined length, an octave hole needs to be disposed in the auxiliary pipe 23h or the blow member 24h. It is possible to arrange a plurality of octave holes whose open/close states are indicated by an indicator means. In this case, the wind instrument 10h is further equipped with an open/close mechanism for opening/closing octave holes in response to the content of the indicator means and the open/close states of the sound holes 25h. 
(5) Fifth Variation
The wind instrument 10d of the fourth embodiment shown in FIG. 10 allows a player to change pitches and tone colors during performance in progress by operating the open/close hole 27d. Instead, it is possible to change pitches and tone colors of the wind instrument 10d by changing the length of the auxiliary pipe 23d. 
FIGS. 16A and 16B illustrate a wind instrument 10i having a pipe structure 20i according to a fifth variation, wherein parts identical to those of the wind instrument 10a are designated by the same reference numerals; hence, the description thereof will be omitted. In the pipe structure 20i, an octave hole 26i is formed in proximity to the hollow joint 22a2 of the main pipe 22a. An auxiliary pipe 23i has a fixed portion 23i1 which is fixed to the main pipe 22a. The fixed portion 23i1 of the auxiliary pipe 23i is configured of a straight pipe composed of a brass or the like. The auxiliary pipe 23i includes a slide pipe 23i2 which is a straight pipe composed of a brass or the like. The slide pipe 23i2 is inserted into the fixed portion 23i1 such that it can vertically move within a predetermined range. In FIG. 16A, the slide pipe 23i2 is disposed at an upper position indicating a length H×Ra of the auxiliary pipe 23i. In FIG. 16B, the slide pipe 23i2 moves downward to a lower position indicating a length Li of the auxiliary pipe 23i. Vertical movement of the slide pipe 23i2 changes the length of an air column resonating inside the auxiliary pipe 23i. The fixed portion 23i1 and the slide pipe 23i2 according to the fifth variation may serve as an auxiliary pipe varying means.
In the state of FIG. 16A, a player plays the wind instrument 10i with the octave hole 26i being opened. In a register of the preset pitch of the sound hole 25a6 or 25a7, an even-number mode of resonance is weakened in the pipe structure 20i, so that the second-mode resonance frequency becomes significantly higher than twice the first-mode resonance frequency which is commensurate with a register one octave higher than the first-mode resonance frequency. In the state of FIG. 16B, a player depresses the slide pipe 23i2 so that the length of an air column resonating inside the auxiliary pipe 23i is shortened compared to that shown in FIG. 16A. In this state, the sound-hole distance Lt becomes adequately longer than the length Li of the auxiliary pipe 23i so as to intensify an even-number mode of resonance in the pipe structure 20i. This makes it possible to produce sound one octave higher than all the registers of the preset pitches of the sound holes 25a; hence, the wind instrument 10i is able to produce sound with preferable pitches and tone colors. According to this constitution, the wind instrument 10i allows players to adjust pitches and tone colors during performance in progress by operating the slide pipe 23i2 of the auxiliary pipe 23i. 
The auxiliary pipe 23i of the wind instrument 10i can be further equipped with a bypass member (or a bypass pipe), which will be described in a sixth variation. The bypass member is able to switch over whether or not an internal path of the auxiliary pipe 23i passes through the bypass pipe. That is, the bypass member changes a pass-through of an air flow so as to change the length of an air column resonating inside the auxiliary pipe 23i. This prevents the length of an air column resonating inside the main pipe 22a from being shortened than the length of an air column resonating inside the auxiliary pipe 23i. Thus, the wind instrument 10i is able to produce sound one octave higher than all the registers of the preset pitches of the sound holes 25a; hence, it is possible to produce sound with preferable pitches and tone colors.
Alternatively, the wind instrument 10i of the fifth variation can be modified to change an internal diameter of the auxiliary pipe 23i, thus changing an amplitude of an air column resonating inside the auxiliary pipe 23i. As a means of changing an internal diameter, it is possible to employ an inner tube which is engaged inside the auxiliary pipe 23i so as to reduce the internal diameter, thus adjusting the tone color of the wind instrument 10i. 
(6) Sixth Variation
The foregoing embodiments are designed to change pitches by use of sound holes, whereas it is possible to employ bypass members for changing pitches. For instance, it is possible to employ bypass members which are conventionally used in trumpets.
FIG. 17 is a plan view of a wind instrument 10j according to a sixth variation, wherein parts equivalent to those of the wind instrument 10a are designated by the corresponding reference numerals suffixed with “j” instead of “a”. The wind instrument 10j differs from the wind instrument 10a in terms of dimensions and quantity; hence, the following description refers to only the differences between the wind instruments 10a and 10j while omitting the similarity therebetween. The wind instrument 10j is constituted of a pipe structure 20j (constituted of straight pipes) and a mouthpiece 30a. The pipe structure 20j includes a main pipe 22j, an auxiliary pipe 23j (commensurate with the auxiliary pipe 23a) and a blow member 24j (commensurate with the blow member 24a), all of which are configured of straight pipes. The main pipe 22j of the wind instrument 10j is longer than the main pipe 22a of the wind instrument 10a, whist the sectional area of the main pipe 22j is smaller than the sectional area of the main pipe 22a. That is, the wind instrument 10j approximates a tapered wind instrument (having a slender upper base) rather than the wind instrument 10a. 
The main pipe 22j is equipped with seven bypass members 28j (i.e. 28j1 through 28j7). The bypass members 28j include bypass pipes having bypass paths which are longer than a main-pipe path corresponding to an internal space of the main pipe 22j. In addition, the bypass members 28j include bypass keys (which allow players to perform bypass operations) and valves (e.g. rotary valves which are interlocked with bypass operations to switch over paths). Upon an operation of the bypass key, the bypass valve moves (or rotates) to switch a pass-through to the bypass path leading to the main-pipe path. With the bypass members 28j being operated, the wind instrument 10j changes the length of an air column resonating inside the main pipe 22j, thus producing sound with desired pitches. The bypass members 28j according to the sixth variation may serve as a pitch adjusting means. When a player operate the bypass member 28j so as to switch the main-pipe path and the bypass path during performance in progress, the wind instrument 10j varies the wavelength of sound resonating inside a branch pipe 21j so as to change pitches. The bypass means 28j are set up in connection with the preset pitches which are determined in advance. The main pipe 22j of the wind instrument 10j is further equipped with trill keys TC, namely a whole-tone trill key TC1 and a semitone trill key TC2. When a player operates the trill key TC while operating any one of the bypass members 28j, the wind instrument 10j changes sound by a whole tone or a semitone.
In order to secure consistency with fingering operations of conventional wood wind instruments, the wind instrument 10j is modified such that the internal space of the main pipe 22j can pass through the bypass path when none of the bypass members 28j is operated. In this state, when a player operates the bypass member 28j, the “bypassed” internal space of the main pipe 22j is shortened so as to reduce the length of an air column, thus increasing pitches. Alternatively, the wind instrument 10j is modified such that the bypass member 28j is installed in the auxiliary pipe 23j so as to change the length of an air column resonating inside the auxiliary pipe 23j during performance in progress. In this connection, this bypass member 28j may serve as an auxiliary pipe varying means.
No sound holes need to be opened during performance of the wind instrument 10j adopting the bypass members 28j for controlling pitches. Therefore, it is possible to achieve silence performance or mute performance by applying mutes to openings 22j1 and 23j1. Of course, the foregoing embodiments and variations can adopt mutes. The wind instrument 10j of FIG. 17 adopts path switches using rotary valves which are conventionally used in French horns or the like. Instead of these path switches using rotary valves, it is possible to employ other path switches using piston valves which are conventionally used in trumpets or the like.
(7) Seventh Variation
The foregoing embodiments are designed to change pitches by use of sound holes of main pipes. Instead, it is possible to change pitches by use of a straight pipe which slides along a main pipe. For instance, it is possible to employ slide pipes which are conventionally used in trombones or the like.
FIGS. 18A and 18B illustrate a wind instrument 10k having a pipe structure 20k according to a seventh variation, wherein parts equivalent to those of the wind instrument 10a are designated by the reference numerals suffixed with “k” instead of “a”; hence, a description thereof will be omitted. The pipe structure 20k of the wind instrument 10k is constituted of the blow member 24a and a branch pipe 21k including the auxiliary pipe 23a and a main pipe 22k. The main pipe 22k has a fixed portion 2k3 which is connected to the auxiliary pipe 23a and the blow member 24a. The fixed portion 22k3 of the main pipe 22k is configured of a straight pipe composed of brass or the like. The main pipe 22k is equipped with a slide pipe 22k4 which is a straight pipe composed of brass or the like. The slide pipe 22k4 is inserted into the fixed portion 22k3 of the main pipe 22k and movable in a certain range of length. The slide pipe 22k4 has an opening 22k1 which is positioned opposite to the fixed portion 22k3. In the pipe structure 20k, an octave hole 26k is formed in proximity to a hollow joint 22k2 of the main pipe 22k. 
In the state of FIG. 18A, the slide pipe 22k4 is disposed at a position indicating a length La of the main pipe 22k. In the state of FIG. 18B, the slide pipe 22k4 moves horizontally to a position indicating a length Lk of the main pipe 22k. According to this constitution, the slide pipe 22k4 attached to the fixed portion 22k3 changes the overall length of the main pipe 22k so as to change the length of an air column resonating inside the main pipe 22k, thus producing desired pitches. When a player operates the slide pipe 22k4 so as to change the length of the main pipe 22k during performance in progress, the wind instrument 10k varies the wavelength of sound resonating inside the branch pipe 21k so as to vary pitches. The slide pipe 22k4 and the fixed portion 22k3 of the main pipe 22k according to the seventh variation may serve as a pitch adjusting means. Compared to conventional wood wind instruments such as saxophones which are able to change pitches in a discrete manner, the wind instrument 10k of the seventh variation can act like trombones to cope with portamento techniques for continuously and smoothly varying pitches.
(8) Eighth Variation
The foregoing embodiments employ linear pipes (e.g. straight pipes) having linear axial directions; but it is possible to employ curved/bent pipes which are partially curved in axial directions. For instance, it is possible to use a single curved/bent pipe as a main pipe, an auxiliary pipe or a blow member. Alternatively, it is possible to use a plurality of curved/bent pipes as a main pipe, an auxiliary pipe and a blow member.
FIG. 19 illustrates a wind instrument 10m having a pipe structure 20m according to an eight variation, wherein parts equivalent to those of the wind instrument 10a are designated by the reference numerals suffixed with “m” instead of “a”; hence, a description thereof will be omitted. The pipe structure 20m is constituted of a main pipe 22m and an auxiliary pipe 23m as well as the blow member 24a. A branch pipe 21m is constituted of the main pipe 22m and the auxiliary pipe 23m, both of which are curved/bent pipes. An opening 22m1 is formed at one end of the main pipe 22m, whilst a hollow joint 22m2 is formed at the other end. The main pipe 22m is connected to the blow member 24a with the hollow joint 22m2, wherein Sa denotes a sectional area of the hollow joint 22m2 which is commensurate with a sectional area of the main pipe 22m. The main pipe 22m is connected to the auxiliary pipe 23m with the side portion of the hollow joint 22m2. Herein, La denotes the length of a center line 22Lm (which is partially meandered or curved) connecting between the center of the sectional area of the opening 22m1 and the center of the sectional area of the hollow joint 22m2.
An opening 23m1 is formed at the upper end of the auxiliary pipe 23m (which is bend and directed horizontally), whilst a hollow joint 23m2 is formed at the lower end of the auxiliary pipe 23m. The auxiliary pipe 23m is connected to the main pipe 22m with the hollow joint 23m2. The internal space of the main pipe 22m is interconnected with the internal space of the auxiliary pipe 23m. That is, the hollow joint 22m2 is disposed at a branch point at which the branch pipe 21m is branched into the main pipe 22m and the auxiliary pipe 23m. Herein, H×Ra denotes the length of a center line 23Lm (which is partially bent) of the auxiliary pipe 23m connecting between the center of a sectional area of the opening 23m1 and the center of a sectional area of the hollow joint 23m2; and H×Sa denotes the sectional area of the opening 23m1 of the auxiliary pipe 23m. The branch pipe 21m is connected to the blow member 24a such that the hollow joint 22m2 is coupled with the hollow joint 24a1. According to this constitution, the wind instrument 10m is designed in a compact size but is able to reproduce pitches and tone colors of the wind instrument 100a shown in FIG. 4.
(9) Ninth Variation
The foregoing embodiments and variations are designed such that auxiliary pipes are connected to the side walls of main pipes, but it is possible to juxtapose openings of main pipes (disposed close to mouthpieces) and openings of auxiliary pipes. In this case, main pipes and auxiliary pipes are not necessarily formed in cylindrical shapes.
The foregoing wind instrument as shown in FIG. 3B, in which an auxiliary pipe is branched inside a mouthpiece, is designed to approximate the original wind instrument 200 shown in FIG. 3A such that the sectional area S of the blow-input portion (i.e. the upper base area of the conical pipe 204) is approximately equal to the sectional area S of the main pipe (i.e. the straight pipe 231); hence, the sum of the sectional area S of the main pipe and the sectional area HS of the auxiliary pipe (i.e. the attachment 801) becomes larger than the sectional area S of the blow-input portion, so that a blowing resistance of the approximate wind instrument of FIG. 3B is smaller than that of the original wind instrument of FIG. 3A. Such a small blowing resistance may disturb a player's long-horn operation for continuing his/her breath to sustain sound, wherein a player may experience difficulty to continuously blowing his/her breaths. A ninth variation is designed to solve this drawback.
FIGS. 20A and 20B illustrate a wind instrument 10n having a pipe structure 20n according to the ninth variation. FIG. 20A is a longitudinal sectional view of the wind instrument 10n. The wind instrument 10n is constituted of a mouthpiece 30n and the pipe structure 20n (including two cylindrical pipes connected together). The pipe structure 20n is composed of a metal such as brass. The pipe structure 20n is constituted of a main pipe 22n and an auxiliary pipe 23n. The main pipe 22n is a cylindrical pipe with a length L and a sectional area Sn, whilst the auxiliary pipe 23n is a cylindrical pipe with a length H×R and a sectional area H×Sn. Openings 22n1 and 22n2 are formed at the opposite ends of the main pipe 22n in the length direction. Openings 23n1 and 23n2 are formed at the opposite ends of the auxiliary pipe 23n in the length direction. The openings 22n2 and 23n2 juxtapose in the same vertical plane so that they are collectively directed to the mouthpiece 30n. The main pipe 22n and the auxiliary pipe 23n are collectively inserted into the mouthpiece 30n via a cork member 40n. 
FIG. 20B is a cross-sectional view taken along line B-B in FIG. 20A. As shown in FIG. 20B, the sectional areas of the main pipe 22n and the auxiliary pipe 23n serve as constituent parts of a circular shape so that the total of these sectional areas is approximately equal to the circular shape having the sectional area S. According to this constitution, the wind instrument 10n approximates an imaginable tapered pipe with a sectional area S at the upper base and a length R ranging from the upper base to the vertex. Since the sum of the sectional area Sn of the main pipe 22n and the sectional area H×Sn of the auxiliary pipe 23n is approximately equal to the sectional area S of the blow-input portion (i.e. the upper base area of the conical pipe 204) of the original wind instrument 200 shown in FIG. 3A, the wind instrument 10n of the ninth variation is able to demonstrate a good blowing sensation comparable to acoustic instruments in addition to the effects of the foregoing embodiments.
The wind instrument 10n is not bulky in shape but has an adequate capacity since the main pipe 22n juxtapose with the auxiliary pipe 23n. In order to form a seamless circular shape by juxtaposing the main pipe 22n and the auxiliary pipe 23n, it is possible to fill gaps, which may be formed between them, with filing materials such as corks and rubbers, thus preventing a player's breath from escaping from gaps.
The wind instrument 10n is designed such that the sum of the sectional area Sn of the main pipe 22n and the sectional area H×Sn of the auxiliary pipe 23n is approximately equal to the sectional area S of the blow-input portion (i.e. the upper base area of the conical pipe 204) of the original wind instrument 200 shown in FIG. 3A; but this is not a restriction. In order to adjust a blowing sensation, it is possible to reduce the sum of the sectional areas Sn and H×Sn to a smaller value than the sectional area S of the blow-input portion of the original wind instrument 200 of FIG. 3A.
(10) Tenth Variation
In the foregoing embodiments, an opening is formed at one end of a main pipe of a wind instrument, but it is possible to attach a pipe member having a specific taper ratio, such as a bell and a tapered pipe, at one end of a main pipe instead of the opening. In the wind instrument 10a, for example, it is possible to additionally attach a bell to the terminal end of the main pipe 22a opposite to the blow member 24a. In this case, the volume of sound is increased by the operation of a bell. Instead of a bell, it is possible to attach a tapered pipe, whose tip end is reduced in size, to the terminal end of the main pipe 22a. According to this constitution in which a main pipe is connected to a pipe member, it is possible to change the volume of sound output from the branch pipe 21a. 
FIGS. 21A and 21B illustrate wind instruments adopting pipe members according to a tenth variation, wherein parts identical to those of the wind instrument 10a are designated by the same reference numerals; hence, the description thereof will be omitted. FIG. 21A is a longitudinal sectional view of a wind instrument 10p adopting a bell 50p. Specifically, the wind instrument 10p is constituted of the pipe structure 20a, the mouthpiece 30a, the cork member 40a and the bell 50p. The bell 50p is a tapered pipe member, composed of a plastic or a metal such as brass, whose taper ratio is continuously varied. The bell 50p is connected to the pipe structure 20a such that the small opening area thereof is coupled with the opening 22a1 of the main pipe 22a. According to this structure, sound resonating inside the pipe structure 20a is amplified and transmitted into the external space.
FIG. 21B is a longitudinal sectional view of a wind instrument 10q adopting a tapered pipe 50q. Specifically, the wind instrument 10q is constituted of the pipe structure 20a, the mouthpiece 30a, the cork member 40a and the tapered pipe 50q. The tapered pipe 50q is a tapered pipe member, composed of a plastic or a metal such as brass, whose taper ratio is continuously varied. The tapered pipe 50q is connected to the pipe structure 20a such that the large sectional area thereof is coupled with the opening 22a1 of the main pipe 22a. According to this constitution, sound resonating inside the pipe structure 20a is attenuated and transmitted into the external space.
(11) Eleventh Variation
In the foregoing embodiments, an auxiliary pipe is connected to the side surface of a main pipe whilst a blow member is connected to a hollow joint opposite to the opening of a main pipe, but it is possible to reverse the positional relationship between the auxiliary pipe and the blow member in connection with the main pipe. In this case, the positional relationship between the main pipe and the auxiliary pipe is similar to that of the pipe unit 220 shown in FIG. 1C.
FIG. 22 illustrates a wind instrument 10r having a pipe structure 20r according to an eleventh variation, wherein parts equivalent to those of the wind instrument 10a are designated by the reference numerals suffixed with “r” instead of “a”; hence, a description thereof will be omitted. FIG. 22 is a longitudinal sectional view of the wind instrument 10r, which is constituted of the pipe structure 20r, a mouthpiece 30r (corresponding to the mouthpiece 30a) and a cork member 40r. The pipe structure 20r is constituted of a main pipe 22r (corresponding to the main pipe 22a), an auxiliary pipe 23r (corresponding to the auxiliary pipe 23a) and a blow member 24r (which is configured of a straight pipe).
The main pipe 22r has an opening 22r1 and a hollow joint 22r2 at opposite ends thereof, wherein the auxiliary pipe 23r is coupled with the hollow joint 22r2. The blow member 24r is connected to the side surface of the main pipe 22r with a hollow joint 22r3. The hollow joint 22r2 is disposed at a branch point at which a branch pipe 21r is branched into the main pipe 22r and the auxiliary pipe 23r. The connected position of the blow member 24r is commensurate with the foregoing position designated by the arrow D2 in FIG. 1C. According to this structure, the wind instrument 10r approximates an imaginary wind instrument including a tapered pipe whose property is realized by the sectional area of the main pipe 22r, the sectional area and length of the auxiliary pipe 23r. 
(12) Twelfth Variation
In the second, third and fourth embodiments, a mouthpiece is detachably attached to a blow member, but it is possible to fix the mouthpiece to the blow member. For instance, a mouthpiece can be fixed to a detachable-connect portion of a blow member via the adhesive. Alternatively, a mouthpiece can be integrally formed together with a blow member.
(13) Thirteenth Variation
The foregoing embodiments are designed to use straight pipes having circular sectional areas, but it is possible to use other types of straight pipes having elliptical sectional shapes or polygonal sectional shapes, wherein these straight pipes are not varied in sectional shapes and sectional areas.
(14) Fourteenth Variation
The foregoing embodiments are designed to use tapered pipes having circular sectional areas, but it is possible to use other types of tapered pipes having elliptical sectional shapes or polygonal sectional shapes, wherein the openings formed at the opposite ends of tapered pipes have similar shapes but the hollow portions of tapered pipes are varied in areas.
(15) Fifteenth Variation
The foregoing embodiments are designed such that main pipes are longer than auxiliary pipes; but this is not a restriction. Both the main pipes and auxiliary pipes may have the same lengths. Alternatively, auxiliary pipes can be longer than main pipes.
(16) Sixteenth Variation
The foregoing embodiments are designed such that branch pipes are constituted of main pipes and auxiliary pipes both of which are configured of straight pipes; but this is not a restriction. One of or both of main pipes and auxiliary pipes can be configured of tapered pipes. In this case, wind instruments are affected by tapered shapes of main/auxiliary pipes so that standing waves occurring inside branch pipes are varied; hence, those wind instruments employing tapered pipes must differ from wind instruments using straight pipes alone in terms of tone colors and pitches.
(17) Seventeenth Variation
In the second embodiment, the wind instrument 10b does not vary the length of an air column resonating inside the blow member 24b, but it is possible to vary the length of an air column resonating inside the blow member 24b by use of a sound hole. In the open state of a sound hole formed in a blow member, an air column of a branch pipe does not resonate. Compared to the closed state of a sound hole of a blow instrument, sound should be significantly varied in tone color and pitch when the sound hole of the blow member is opened. This sound hole formed in a blow member may serve as a pitch adjusting means.
FIG. 23 illustrates a wind instrument 100s (which serves as a basis of a seventeen variation), which is constituted of a pipe structure 120s and a mouthpiece 130s. The pipe structure 120s is constituted of a tapered pipe 124s and a bell 150s. The tapered pipe 124s has a tapered shape having upper and lower bases, wherein S2s denotes a sectional area of the upper base, and S1s denotes a sectional area of the lower base. The mouthpiece 130s is attached to the upper base of the tapered pipe 124s. A plurality of sound holes 125s is formed on the side surface of the tapered pipe 124s. An opening 150s1 is formed at one end of the bell 150s, whilst a hollow joint 150s2 is formed at the other end. Herein, Ls2 denotes a distance between the opening 150s1 and the hollow joint 150s2. The bell 150s is connected to the tapered pipe 124s with the hollow joint 150s2. The bell 150s approximates an imaginary tapered pipe in which S1s denotes the sectional area of the upper base, Ls1 denotes the length, and Rs1 denotes the distance between the upper base to the vertex.
FIG. 24 illustrates a wind instrument 10t according to a seventeenth variation, wherein parts equivalent to those of the wind instrument 100s are designated by the two-digit reference numerals precluding hundredth places. A pipe structure 20t is constituted of a main pipe 22t, an auxiliary pipe 23t and a blow member 24s. The blow member 24s has the same constitution as the tapered pipe 124s of the wind instrument 100s. A branch pipe 21t is constituted of the main pine 22t and the auxiliary pipe 23t, which are configured of straight pipes. An opening 22t1 is formed at one end of the main pipe 22t, whilst a hollow joint 22t2 is formed at the other end. The main pipe 22t, the auxiliary pipe 23t and the blow member 24s are placed in the same positional relationship as the main pipe 22a, the auxiliary pipe 23a and the blow member 24a in the pipe structure 20a of the wind instrument 10a. 
Ls1 denotes a distance ranging from the opening 22t1 of the main pipe 22t to a center line Dt of the auxiliary pipe 23t. When the auxiliary pipe 23t is designed with a length H×Rs1 and a sectional area H×S1s, the branch pipe 21t approximates an imaginary tapered pipe in which Rs1 denotes a distance ranging from the upper base to the vertex, S1s designates the sectional area of the upper base, and Ls1 denotes the length ranging from the upper base to the lower base, wherein H denotes a positive constant in Equation (6). That is, the branch pipe 21t approximates the bell 150s. For this reason, the wind instrument 10t approximates the wind instrument 100s in terms of tone colors and pitches.
(18) Eighteenth Variation
In the second embodiment, the wind instrument 10b does not vary the length of an air column resonating inside the blow member 24b, but it is possible to vary the length of an air column resonating inside the blow member 24b by way of a bypass pipe. A bypass pipe attached to a blow member varies the distance from a mouthpiece to a main pipe or an auxiliary pipe so as to vary a blowing sensation imparted to player's lips, thus varying tone pitches. Such a bypass pipe attached to a blow member may serve as a pitch adjusting means.
FIG. 25 illustrates a wind instrument 100u (which serves as the basis of an eighteenth variation), which is constituted of a pipe structure 120u, a mouthpiece 130u and a mouthpiece attachment 132u. The pipe structure 120u is constituted of a tapered pipe 124u1, a straight pipe 124u2 and a bell 150u. The mouthpiece 130u is attached to the pipe structure 120u via the mouthpiece attachment 132u. A blow member 124u is constituted of the tapered pipe 124u1 and the straight pipe 124u2. The mouthpiece 130u is attached to the upper base of the tapered pipe 124u1. The straight pipe 124u2 is equipped with bypass members 128u (namely, bypass members 128u1, 128u2 and 128u3). The bypass members 128u are used to form bypass paths which elongate a straight-pipe path formed inside the straight pipe 124u2. The bypass members 128u include bypass keys (allowing players to perform bypass operations) and valves (switching paths interlocked with bypass operations). Upon being operated, bypass keys move (or rotate) valves (i.e. rotary valves) so as to switch over pass-through to bypass paths interconnected with the straight-pipe path. That is, the bypass members 128u are used to change the length of an air column resonating inside the straight pipe 124u2, thus producing desired pitches.
An opening 150u1 is formed at one end of the bell 150u, whilst a hollow joint 150u2 is formed at the other end. Herein, Lu2 denotes the distance between the opening 150u1 and the hollow joint 152u2. The bell 150u is connected to the straight pipe 124u2 with the hollow joint 150u2. The bell 150u approximate an imaginary tapered pipe in which S1u denotes the sectional area of the upper base, Lu1 denotes the length, and Ru1 denotes the distance ranging from the upper base to the vertex.
FIG. 26 is a longitudinal sectional view of a wind instrument 10v having a pipe structure 20v according to an eighteenth variation, wherein parts identical to those of the wind instrument 100u are designated by two-digit reference numerals precluding hundredth places from three-digit reference numerals shown in FIG. 25; hence, a description thereof will be omitted. The pipe structure 20v is constituted of a main pipe 22v, an auxiliary pipe 23v and a blow member 24u. The blow member 24u has the same constitution as the blow member 124u of the wind instrument 100u. A branch pipe 21v is constituted of the main pipe 22v and the auxiliary pipe 23v, which are configured of straight pipes. An opening 22v1 is formed at one end of the main pipe 22v, whilst a hollow joint 22v2 is formed at the other end. Herein, the main pipe 22v, the auxiliary pipe 23v and the blow member 24u are placed in the same positional relationship as the main pipe 22a, the auxiliary pipe 23a and the blow member 24a in the pipe structure 20a of the wind instrument 10a. 
Lu1 denotes the distance from the opening 22v1 of the main pipe 22v to a center line Dv of the auxiliary pipe 23v. When the auxiliary pipe 23v is designed with a length H×Ru1 and a sectional area H×S1u, the branch pipe 21v approximates an imaginary tapered pipe in which Ru1 denotes the distance from the upper base to the vertex, S1u denotes the sectional area of the upper base, and Lu1 denotes the length between the upper base and the lower base, wherein H denotes a positive constant in Equation (6). That is, the branch pipe 21v approximates the bell 150s. For this reason, tones color and pitches of the wind instrument are approximate to those of the wind instrument 100s. In FIGS. 25 and 26, the bypass members 28u use rotary valves (which are conventionally used in French horns) as switches, but it is possible to use piston valves (which are conventionally used in trumpets).
(19) Nineteenth Variation
In the second embodiment, the wind instrument 10b does not vary the length of an air column resonating inside the blow member 24b, but it is possible to vary the length of an air column resonating inside the blow member 24b by use of a slide pipe attached to the blow member 24b. A slide pipe attached to a blow member varies the distance between a mouthpiece and an auxiliary pipe so as to vary a blowing sensation imparted to player's lips, thus varying pitches. Such a slide pipe attached to a blow member may serve as a pitch adjusting means.
(20) Twentieth Variation
In the seventeenth, eighteenth and nineteenth variations, a pitch adjusting means is attached to the blow member, but it is possible to attach a pitch adjusting means to both the main pipe and the blow member. In this case, different pitch adjusting means (having different configurations selected from among sound holes, bypass members and slide pipes) can be applied to each of the main pipe and the blow member.
(21) Twenty-First Variation
In the ninth variation, the wind instrument 10n is designed such that the main pipe 22n and the auxiliary pipe 23n vertically juxtapose with the openings 22n2 and 23n2 in proximity to the mouthpiece 30n, but it is possible to combine the main pipe 22n and the auxiliary pipe 23n in a concentric manner.
FIGS. 27A and 27B illustrate a wind instrument 10w having a pipe structure 20w according to a twenty-first variation. FIG. 27A is a longitudinal sectional view of the wind instrument 10w in which a mouthpiece 30w is attached to the pipe structure 20w, which is constituted of a main pipe 22w and an auxiliary pipe 23w. The main pipe 22w is installed inside the auxiliary pipe 23w having a cylindrical shape. The pipe structure 20w is composed of a metal such as a brass. The pipe structure 20w has a concentric cylindrical shape combining the main pipe 22w and the auxiliary pipe 23w. The main pipe 22w is a cylindrical pipe with a length L and a sectional area Sw, whilst the auxiliary pipe 23w is a cylindrical shape with a length H×R and a sectional area H×Sw.
Openings 22w1 and 22w2 are formed at the opposite ends of the main pipe 22w in the length direction, whilst openings 23w1 and 23w2 are formed at the opposite ends of the auxiliary pipe 23w in the length direction. The openings 22w2 and 23w2 are placed in the same plane in connection with the mouthpiece 30w. The mouthpiece 30w is connected to the auxiliary pipe 23w via a cork member 40w. The auxiliary pipe 23w is interconnected with the main pipe 22w via supports 41w. 
FIG. 27B is a cross-sectional view taken along line C-C in FIG. 27A. The internal space of the main pipe 22w is surrounded by the internal wall of the main pipe 22w, wherein it has the sectional area Sw. The internal space of the auxiliary pipe 23w is surrounded by the internal wall of the auxiliary pipe 23w, the external wall of the main pipe 22w and the side walls of the supports 41w, wherein it has the sectional area of H×Sw. In the twenty-first variation as shown in FIG. 27B, the internal space of the auxiliary pipe 23w is partitioned into three divisions by means of three supports 41w, wherein each division has a sectional area of 1⁄3×H×Sw. That is, the internal space of the main pipe 22w and the internal space of the auxiliary pipe 23w constitute parts of a circular shape in a cross section, wherein the total of those internal spaces is approximately equal to the sectional area S of a circular shape (i.e. an interior-wall shape of the auxiliary pipe 23w). According to this constitution, the pipe structure 20w approximates an imaginary tapered pipe in which S denotes the sectional area of the upper base, and R denotes the length between the upper base and the vertex.
FIG. 31 illustrates acoustic characteristics with regard to the wind instrument 10w of the twenty-first variation. In FIG. 31, F denotes an input impedance curve of the wind instrument 100a of FIG. 4 in which the mouthpiece 130a is connected to a conical pipe (i.e. the pipe unit 120a); G denotes an input impedance curve of the wind instrument 100a of FIG. 4 approximating the structure of FIG. 3B in which the auxiliary pipe (i.e. the attachment 801) is branched inside the mouthpiece 300 while the sectional area S of the main pipe (i.e. the straight pipe 231) is equal to the sectional area Sa2 on the upper base of the conical pipe (i.e. the pipe unit 120a) shown in FIG. 4 and in which all the sound holes (not shown) are closed; and H denotes an input impedance curve of the wind instrument 10w of the twenty-first variation in which the sum of the internal space of the main pipe 22w and the internal space of the auxiliary pipe 23w, i.e. Sw+H×Sw, is approximately equal to the sectional area S2a of the upper base of the conical pipe (i.e. the pipe unit 120a) shown in FIG. 4 and in which all the sound holes are closed.
Compared with the conventional branch-type wind instrument (having the input impedance curve G) as shown in FIG. 3B in which the auxiliary pipe is branched inside the mouthpiece and in which the sectional area S of the main pipe (i.e. the straight pipe 231) is equal to the sectional area S2a of the upper base of the conical pipe (i.e. the pipe unit 120a) shown in FIG. 4, the input impedance curve H of the twenty-first variation is close to the input impedance curve F of the original wind instrument 100a of FIG. 4 particularly in terms of the peak value of a low frequency component, proving that the twenty-first variation achieves good acoustic characteristics.
Since the sum of the sectional area Sw of the main pipe 22w and the sectional area H×Sw of the auxiliary pipe 23w is approximately equal to the sectional area S of the blow-input portion of the original wind instrument 200 (i.e. the upper base area of the conical pipe 204) shown in FIG. 3A, the twenty-first variation is advantageous over other embodiments/variations and is able to achieve a good blowing sensation comparable to conventional acoustic instruments in addition to the same effects as the foregoing embodiments/variations.
Since the auxiliary pipe 23w is disposed along and outside the main pipe 22w, the wind instrument 10w is not bulky in size but achieves a high capacity.
Although the wind instrument 10w is designed such that the sum of the sectional area Sw of the main pipe 22w and the sectional area H×Sw of the auxiliary pipe 23w is approximate to the sectional area S of the blow-input portion (i.e. the upper base area of the conical pipe 204) of the original wind instrument 200 shown in FIG. 3A, it is possible to modify the wind instrument 10w such that the sum of the sectional areas Sw and H×Sw is smaller than the sectional area S of the blow-input portion of the original wind instrument 200 in order to adjust a blowing sensation.
(22) Twenty-Second Variation
In the first embodiment of FIGS. 6A and 6B, the wind instrument 10a is designed such that the sectional area of the main pipe 22a is equal to the sectional area of the blow member 24a, so that the sum of the sectional area Sa of the main pipe 22a and the sectional area H×Sa of the auxiliary pipe 23a becomes larger than the sectional area Sa at the terminal end of the blow member 24a. Compared with the wind instrument of FIG. 3B in which the auxiliary pipe is branched inside the mouthpiece, the wind instrument 10a demonstrates a good blowing resistance, which is lower than that of the wind instrument 100a of FIG. 4. Such a low blowing resistance may cause a player to experience a difficulty in sustaining his/her breath which needs to be continuously applied to the wind instrument 10a in a long-horn technique. A twenty-second variation is designed to solve this drawback.
FIGS. 28A and 28B illustrate a wind instrument 10x having a pipe structure 20x according to the twenty-second variation, wherein parts equivalent to those shown in FIGS. 27A and 27B are designated by the reference numerals suffixed with “x” instead of “w”; hence, the description thereof will be omitted. FIG. 28A is a longitudinal sectional view of the wind instrument 10x, which is constituted of a main pipe 22x, an auxiliary pipe 23x, a blow member 24x and a mouthpiece 30x. The main pipe 22x having a cylindrical shape is partially inserted into the auxiliary pipe 23x having a cylindrical shape. The pipe structure 20x is composed of a metal such as brass and constituted such that two cylindrical pipes consisting of the main pipe 22x and the auxiliary pipe 23x are connected to the blow member 24x. The main pipe 22x is a cylindrical pipe having a length La and a sectional area Sx, whilst the auxiliary pipe 23x is a cylindrical pipe having a length H×Ra and an internal sectional area of H×Sx.
Openings 22x1 and 22x2 are formed at the opposite ends of the main pipe 22x in the length direction, whilst openings 23x1 and 23x2 are formed at the opposite ends of the auxiliary pipe 23x in the length direction. The opening 22x2 of the main pipe 22x and the opening 23x2 of the auxiliary pipe 23x3 are placed in the same plane in connection with the blow member 24x in the direction of the mouthpiece 30x. The mouthpiece 30x is connected to the blow member 24x via a cork member 40x. The auxiliary pipe 23x is connected to the main pipe 22x via supports 41x. 
FIG. 28B is a cross-sectional view of the wind instrument 10x along with a line D-D in FIG. 28A. The internal space of the main pipe 22x is surrounded by the internal wall of the main pipe 22x, wherein it has the sectional area Sx. The internal space of the auxiliary pipe 23x is surrounded by the internal wall of the auxiliary pipe 23x, the external wall of the main pipe 22x and the side walls of the supports 41x, wherein it has the sectional area H×Sx. In the twenty-second variation shown in FIG. 28B, the internal space of the auxiliary pipe 23x is divided into three divisions via three supports 41x, wherein each division has a sectional area of 1⁄3×H×Sx. That is, the internal space of the main pipe 22x and the internal space of the auxiliary pipe 23x constitute parts of a circular shape, wherein the sum of those spaces is approximately equal to the sectional area Sa of a circular shape (i.e. an internal-wall shape of the auxiliary pipe 23x). According to this constitution, the wind instrument 10x approximates an imaginary wind instrument having a tapered pipe in which Sa denotes the sectional area of the upper base, and Ra denotes the distance between the upper base and the vertex.
FIG. 32 illustrates acoustic characteristics of the wind instrument 10x of the twenty-second variation. In FIG. 32, I denotes an input impedance curve of the wind instrument 100a of FIG. 4 in which the mouthpiece 130a is connected to the conical pipe (i.e. the pipe unit 120a); J denotes an input impedance curve of the wind instrument 10a of FIG. 6B in which the branch pipe 21a approximates the blow member 24a and onwards so as to approximate the structure of FIG. 4, in which both the sectional area of the terminal end of the blow member (i.e. the tapered pipe 124a) and the sectional area of the main pipe 22a are equal to Sa so that the sum of the sectional area of the main pipe 22a and the sectional area of the auxiliary pipe 23a becomes larger than the sectional area Sa of the terminal end of the blow member, and in which all the sound holes are closed; and K denotes an input impedance curve of the wind instrument 10x of the twenty-second variation in which the sum of the sectional area Sx of the main pipe 22x and the sectional area H×Sx of the auxiliary pipe 23x is approximately equal to the sectional area (i.e. Sa shown in FIG. 4) of the terminal end of the blow member (i.e. the tapered pipe 124a) and in which all the sound holes are closed.
Compared to the wind instrument 10a of the first embodiment (having the input impedance curve J) shown in FIG. 6B in which both the sectional area of the main pipe 22a and the sectional area of the terminal end of the blow member 24a are equal to Sa, the input impedance curve K of the twenty-second variation is close to the input impedance curve I of the original wind instrument 100a shown in FIG. 4 particularly in terms of the peak value of a low frequency component, so that the twenty-second variation achieves good acoustic characteristics.
Since the sum of the sectional area Sx of the main pipe 22x and the sectional area H×Sx of the auxiliary pipe 23x is approximate to the sectional area Sa of the blow-input portion (i.e. the tapered pipe 124a) of the original wind instrument 100a of FIG. 4, the wind instrument 10x is able to demonstrate a good blowing sensation (which is comparable to that of acoustic instruments) and the effects of the foregoing embodiments.
Since the auxiliary pipe 23x is arranged along and outside the main pipe 22x, the wind instrument 10x is not bulky in shape but has an adequate capacity. Instead of the constitution in which the auxiliary pipe 23x is not necessarily arranged outside the main pipe 22x, it is possible to employ another constitution in which the auxiliary pipe 23x is vertically branched from the terminal end of the blow member 24x. In this constitution, the sum of the sectional area Sx of the main pipe 22x and the sectional area H×Sx of the auxiliary pipe 23x does not need to be identified with the sectional area Sa of the blow-input portion of the original wind instrument 100a of FIG. 4, whereas the sum of the sectional areas Sx and H×Sx can be smaller than the sectional area Sa of the blow-input portion of the original wind instrument 100a of FIG. 4 in order to adjust a blowing sensation. That is, it is possible to increase a blowing resistance on the condition that the sum of the input sectional area Sx of the main pipe 22x and the input sectional area H×Sx of the auxiliary pipe 23x remains lower than the terminal sectional area Sa of the blow member 24x. 
Lastly, the present invention is not necessarily limited to the foregoing embodiments and variations, which can be further modified in various ways within the scope of the invention as defined by the appended claims.

## Claims

1. A pipe structure of a wind instrument comprising:
a blow member connectable to a mouthpiece; and
a branch pipe composed of a main pipe and an auxiliary pipe joined to the main pipe, and configured to simulate a tapered pipe,
wherein the blow member is connected to the branch point of the branch pipe at a point where the auxiliary pipe joins the main pipe,
wherein the auxiliary pipe has an open distal end,
wherein the main pipe has a first adjuster that adjusts a pitch sounded by the wind instrument,
wherein the auxiliary pipe has a second adjuster that varies a length of an air column resonating inside the auxiliary pipe, and
wherein the branch pipe is configured to allow an air blown into the blow member to flow through the main pipe and the auxiliary pipe.

2. The pipe structure of a wind instrument according to claim 1, wherein the first adjuster comprises a sound hole, a bypass pipe or a slide pipe.

3. The pipe structure of a wind instrument according to claim 1, wherein the main pipe and the auxiliary pipe are straight pipes having different lengths.

4. The pipe structure of a wind instrument according to claim 1, wherein:
the second adjuster comprises at least one closable open hole formed on a side wall of the auxiliary pipe, and
the length of an air column resonating inside the auxiliary pipe varies in response to closing or opening of the closable open hole.

5. The pipe structure of a wind instrument according to claim 1, wherein:
the second adjuster comprises a slide pipe movable within the auxiliary pipe, and
the length of an air column resonating inside the auxiliary pipe varies in response to a sliding operation of the slide pipe.

6. The pipe structure of a wind instrument according to claim 1, wherein:
the first adjuster comprises a bypass pipe attached to the main pipe, and
a length of an air column resonating inside the main pipe varies in response to a pass-through switched over from an internal path of the main pipe to the bypass pipe.

7. The pipe structure of a wind instrument according to claim 3, wherein the main pipe has a passageway having a constant diameter.

8. The pipe structure of a wind instrument according to claim 1, wherein the blow member has a tapered passageway that is wider toward the branch pipe.

9. The pipe structure of a wind instrument according to claim 1, wherein the length of an air column resonating inside the auxiliary pipe is shortenable with the second adjuster to prevent unexpected variations of a tone color when a high pitch sound is produced.

10. A wind instrument comprising:
a mouth piece; and
a pipe structure comprising:
a blow member connected to the mouthpiece; and
a branch pipe composed of a main pipe and an auxiliary pipe joined to the main pipe, and configured to simulate a tapered pipe,
wherein the blow member is connected to the branch pipe at a point where the auxiliary pipe joins the main pipe,
wherein the auxiliary pipe has an open distal end,
wherein the main pipe has a first adjuster that adjusts a pitch sounded by the wind instrument,
wherein the auxiliary pipe has a second adjuster that varies a length of an air column resonating inside the auxiliary pipe, and
wherein the branch pipe is configured to allow an air blown into the blow member to flow through the main pipe and the auxiliary pipe.

11. The wind instrument according to claim 10, wherein the first adjuster comprises a sound hole, a bypass pipe or a slide pipe.

12. The wind instrument according to claim 10, wherein the main pipe and the auxiliary pipe are straight pipes having different lengths.

13. The wind instrument according to claim 10, wherein:
the second adjuster comprises at least one closable open hole formed on a side wall of the auxiliary pipe, and
the length of an air column resonating inside the auxiliary pipe varies in response to opening or closing of the closable open hole.

14. The wind instrument according to claim 10, wherein:
the second adjuster comprises a slide pipe movable within the auxiliary pipe, and
the length of an air column resonating inside the auxiliary pipe varies in response to a sliding operation of the slide pipe.

15. The wind instrument according to claim 10, wherein:
the first adjuster comprises a bypass pipe attached to the main pipe, and
a length of an air column resonating inside the main pipe varies in response to a pass-through switched over from an internal path of the main pipe to the bypass pipe.

16. The wind instrument according to claim 12, wherein the main pipe has a passageway having a constant diameter.

17. The wind instrument according to claim 10, wherein the blow member has a tapered passageway that is wider toward the branch pipe.

18. The wind instrument according to claim 10, wherein the length of an air column resonating inside the auxiliary pipe is shortenable with the second adjuster to prevent unexpected variations of a tone color when a high pitch sound is produced.

19. A method of operating a wind instrument comprising:
a mouth piece; and
a pipe structure comprising:
a blow member connected to the mouthpiece; and
a branch pipe composed of a main pipe and an auxiliary pipe joined to the main pipe, and configured to simulate a tapered pipe,
wherein the blow member is connected to the branch pipe at a point where the auxiliary pipe joins the main pipe,
wherein the auxiliary pipe has an open distal end,
wherein the main pipe has a first adjuster that adjusts a pitch sounded by the wind instrument,
wherein the auxiliary pipe has a second adjuster that varies a length of an air column resonating inside the auxiliary pipe,
wherein the branch pipe is configured to allow an air blown into the blow member to flow through the main pipe and the auxiliary pipe,
the method comprising the steps of:
blowing air through the mouth piece while maintaining the open distal end of the auxiliary pipe unobstructed; and
operating the second adjuster to vary the length of the air column resonating inside the auxiliary pipe while maintaining the open distal end of the auxiliary pipe unobstructed.

20. The method according to claim 19, wherein the blow member has a tapered passageway that is wider toward the branch pipe.

21. The method according to claim 19, further comprising the step of operating the second adjuster to shorten the length of an air column resonating inside the auxiliary pipe while a high pitch is produced to prevent unexpected variations of a tone color, while maintaining the open distal end of the auxiliary pipe unobstructed.