All-metal tube of multi-sound-window convertible tube and string integrated Erhu

Abstract

The utility model relates to a Chinese national musical instrument Erhu, in particular to an all-metal tube of a multi-sound-window convertible tube and string integrated Erhu, which mainly comprises a rod sleeve, a semi-hexagonal frame, a simple body with skin (film), an inner column and an outer column for fixing a support, convertible multifunctional sound windows and other metal parts which are all made of the same metal material. The metal wall of the inner cavity of the cylinder is integrally complete and smooth without any mounting gap, the inner cavity is not provided with a rod, and the volume of an air column in the inner cavity is most complete and maximized; the functional sound window is mainly composed of a plurality of metal tube sound windows with different structural characteristics such as length, thickness, horizontal and vertical directions and curved and straight directions of a cylindrical tube body of a wind instrument, and the functional sound windows matched with music emotion or range can be selected by a user independently and can be combined and installed with the Erhu simply and conveniently. The tube and string integrated Erhu all-metal tube with the convertible multiple sound windows is mainly composed of Erhu string music and is assisted by wind music, and the string music and the wind music are compatible in form and durable in use.

Description

Technical Field

[0001] The utility model relates to a traditional Chinese national stringed instrument, an erhu, in particular to an erhu full-metal sound box with a multi-tone window and a changeable integrated string instrument.

[0002] The purpose of the utility model is to keep the main structure of the appearance of the traditional Chinese folk musical instrument Erhu basically unchanged, and at the same time, ensure that the user's personal playing skills and operating habits originally possessed will not be negatively affected when the user operates the Erhu product manufactured by applying the technology of the utility model. Under the premise, the sound box, sound skin, sound window, a specially matched sound bar cover and a semi-hexagonal frame of a semi-hexagonal shape of the traditional musical instrument Erhu are all made of the same metal material with excellent strength, flexibility, sound absorption and chemical stability, etc., and are organically combined to produce a full metal sound box with independent functional sound windows that can be conveniently adjusted and changed with each other, a sound box cavity that is completely empty, a metal wall surface of the sound box cavity that is complete and smooth without any defects, a sound box cavity that has the most complete and maximized air column volume, and a sound box resonance box in which the oscillation and conduction of the harmonics of the piano sound are particularly sufficient and smooth.

[0003] At the same time, the multi-tone window at the rear end of the all-metal sound box that can be conveniently adjusted, transformed, connected and installed, except for retaining a type of sound window with a main structure that is basically the same as the traditional erhu sound box sound window, all other multi-tone windows are composed of a variety of metal pipe sound windows with the main structural modeling characteristics of wind instruments, so that the main structure of the erhu all-metal sound box of the utility model stringed instrument is organically integrated with a variety of metal pipe sound windows with the main structural modeling characteristics of wind instruments, and organically combined into a full-metal sound box of the erhu with integrated string and string. In addition, it has the dual-purpose functional characteristics of being used as both an erhu with integrated string and string and a traditional erhu. Therefore, an independent functional sound window is produced, by which users can independently select an independent functional sound window that matches the emotion or range of the music from a variety of adjustable and transformable independent functional sound windows, especially from a variety of adjustable and transformable metal tube sound windows, and is conveniently adjusted and transformed and connected and installed on the back end of the erhu sound box. This is a new type of structure with multiple sound windows and transformable orchestral erhu all-metal sound box, which is mainly erhu string instruments and supplemented by wind instruments, and is compatible with both string and wind instruments in form and durable. Background Art

[0004] For many years, the sound box and sound window of the erhu, a traditional Chinese string instrument, have been basically made of wood. In recent years, a very small number of erhu products have appeared with erhu sound boxes made of metal or other materials alone. However, no matter what material is used to make the erhu sound box, the product structure is basically the same as the traditional wooden erhu sound box. That is, the mutual connection and installation between the erhu sound box and the erhu bar are first processed by drilling holes in the specific upper and lower vertical parts of the sound box, and then the bar is inserted into the drilled hole and passed through the entire sound box for combined and fixed installation. Therefore, the finished erhu products currently on the market all have a vertical neck that passes vertically through the entire sound box at a close distance to the vertical part of the inner cavity of the sound box close to the central source of the sound wave vibration of the sound box skin. Even for a metal sound box, it is difficult to make the inner cavity wall of the sound box complete and smooth without any surface defects. The volume of the air column in the inner cavity of the sound box cannot be the most complete and maximized, and the oscillation and conduction of the resonance harmonics of the sound in the resonance box of the sound box cannot always be the most complete and smooth.

[0005] At the same time, the skin used for the sound box of the erhu, a traditional Chinese stringed instrument, is made of natural leather membranes such as python skin or snake skin, or artificial leather membranes that have appeared in recent years. The skin and sound box are also independent accessories of traditional erhu products.

[0006] In addition, for many years, the sound window located at the rear end of the traditional erhu sound box has been a permanently fixed installation structure for each individual erhu product. That is, except for the possible differences in the hollow carved patterns of the sound windows between individual erhu products, the main structure of all traditional erhu sound windows and their permanent fixed connection and installation methods with the rear end of the erhu sound box are all the same.

[0007] In summary, the multi-tone window changeable orchestral erhu full metal sound box which can be made into one with the following four functional features has not yet appeared in the domestic erhu product field and is still blank:

[0008] 1. The sound box and the sound skin of the erhu are made of the same piece of metal material to form an integrated independent part of the erhu sound box, so that the transition area between the entire sound skin at the front end of the erhu sound box and the inner and outer edges of the circumference of the front end of the sound box does not need to be connected with a skin, and there is no connection or installation gap, and the whole is integrated and smooth.

[0009] Second, the erhu's sound box, sound skin, sound window, and special accessories such as the neck sleeve and semi-hexagonal frame are all made of the same metal material and organically combined to form an erhu full metal sound box. Among them, the setting of the neck sleeve and the semi-hexagonal frame, which are two parts of the erhu sound box, can not only completely eliminate the original vertical upright neck that originally blocked the sound wave vibration center of the sound skin at a close distance in the traditional erhu sound box, and passed through the entire sound box and was fixedly connected and installed with the sound box, but also make the metal inner wall of the full metal sound box cavity present an overall complete and smooth surface without any wall defects, and the air column volume of the sound box cavity is also the most complete and maximized, and the oscillation and conduction of the resonance harmonics of the sound in the sound box resonance box are also particularly full and smooth. At the same time, for users who are accustomed to using hexagonal or octagonal erhu sound boxes, when bowing on a round full metal sound box, it has an automatic conversion function to still bow on a hexagonal or octagonal erhu sound box.

[0010] 3. The sound window at the rear end of the erhu sound box is changed from the traditional permanently fixed installation structure to a structure in which the user can independently match and select any independent function sound window among multiple sound windows with their own independent functions according to the emotion of the music or the requirements of the sound range, and the structure is conveniently installed, adjusted and transformed with the rear end of the erhu sound box.

[0011] Fourth, among the polyphonic windows that can be conveniently adjusted and changed at the back end of the erhu sound box, except for some polyphonic windows that retain the same main structure as the traditional erhu sound box sound window, all other polyphonic windows are made into metal tube sound windows with the main structural characteristics of wind instruments. In the main structure of the erhu sound box of the stringed instrument, the various structural characteristics of the cylindrical tube body of the metal tube sound window are organically integrated, so that the air column in the inner cavity of the erhu sound box and the air column in the inner cavity of the metal tube sound window pipe are interconnected and integrated, and organically combined into an all-metal sound box of the string-and-string erhu. At the same time, it has the dual-purpose functional characteristics of being used as both a string-and-string erhu and a traditional erhu. Thus, an independent functional sound window is produced, by which users can independently select an independent functional sound window that matches the emotion or range of the music from a variety of adjustable and transformable independent functional sound windows, especially from a variety of adjustable and transformable metal tube sound windows, and is conveniently adjusted and transformed and connected and installed on the back end of the erhu sound box. This is a new type of structure with multiple sound windows and transformable orchestral erhu all-metal sound box that is mainly composed of string instruments and supplemented by wind instruments, and is compatible with both string and wind instruments in form and durable. Summary of the invention

[0012] The utility model discloses a multi-tone window changeable orchestral integrated erhu full metal sound box, wherein the full metal sound box includes two structural modes: a sound box structure with a self-attached sound box skin and a sound box structure with a through hole sound box. The through hole sound box structure includes two types of full metal sound boxes: a full metal sound box with a through hole frame sound box structure and a full metal sound box with a hexagonal through hole sound box structure. All components of the full metal sound boxes with the two structural modes are all made of the same metal material, such as stainless steel, copper or silver. The full metal sound boxes with the two structural modes are different from each other in terms of the main structure and functional characteristics, except for the difference in the structure in which the sound box and the sound box skin are connected to each other and the shape of the sound box.

[0013] The all-metal sound box with a self-contained sound skin frame sound box structure is assembled and installed by a sound bar sleeve, a first half hexagonal frame, a sound box with a self-contained sound skin frame, a sound support fixing inner column, a sound support fixing outer column and a metal sound window. A sound bar that does not extend into the sound box with the self-contained sound skin frame is inserted into the sound bar sleeve. The sound bar sleeve is welded and fixed to the first half hexagonal frame. The first half hexagonal frame is arranged on the upper part of the sound box with the self-contained sound skin frame. The sound box with the self-contained sound skin frame and the sound box with its own sound skin are single independent components of an integral integrated sound box made of the same piece of metal material. There are multiple types of metal sound windows, and the user can choose any one of them to connect and install it with the rear end of the sound box in a convenient way.

[0014] The all-metal sound box of the through-hole frame sound box structure is assembled and installed by a neck sleeve, a second half-hexagonal frame, a through-hole frame sound box, a sound box skin, a half-hexagonal pressing plate, a sound box support fixing inner column, a sound box support fixing outer column and a metal sound window. A neck sleeve is inserted with a sound box rod that does not extend into the through-hole frame sound box. The neck sleeve is arranged on the second half-hexagonal frame, and the second half-hexagonal frame is arranged on the upper part of the through-hole frame sound box. The sound box skin is fixed to one end of the through-hole frame sound box, and the half-hexagonal pressing plate presses the upper part of the sound box skin. The sound box support fixing inner column and the sound box support fixing outer column are both arranged at the bottom of the through-hole frame sound box. Similarly, there are multiple types of metal sound windows, and the user can choose any one of them to be conveniently adjusted, transformed, connected and installed with the back end of the sound box.

[0015] The all-metal sound box with a through-hole frame sound box structure is composed of a neck sleeve, a sound box skin, a sound box skin edging, a hexagonal through-hole sound box, a sound box support fixed inner column, a sound box support fixed outer column and a metal sound window. A neck that does not extend into the hexagonal through-hole sound box is inserted into the neck sleeve, the neck sleeve is arranged on the top of the hexagonal through-hole sound box, the sound box skin edging presses the sound box against one end of the hexagonal through-hole sound box, the sound box support fixed inner column and the sound box support fixed outer column are both arranged on the bottom of the hexagonal through-hole sound box. Similarly, there are multiple types of metal sound windows, and the user can choose any one of them to connect and install it with the rear end of the sound box in a convenient way.

[0016] As a further improvement of the present invention, the structural features and functional characteristics of the neck sleeve, the first half hexagonal frame and the second half hexagonal frame are completely the same.

[0017] As a further improvement of the present invention, there are three types of metal sound windows that can be conveniently transformed, combined, connected and installed with the rear end of the all-metal sound box, namely, tube sound windows, flat cover sound windows and flat cover tube sound windows. Among them, the metal tube sound window composed of the tube sound window and the flat cover tube sound window, the tube fittings of its components are all composed of cylindrical through-hole metal tubes, or cylindrical through-hole metal tubes and a number of through-hole metal tube elbows with the same tube diameter as the tube, and all have the main structural modeling characteristics of the cylindrical tube body of a wind instrument, and respectively include the following tube fittings: short thin straight tube fittings, long thin straight Pipe fittings, short and thick straight pipe fittings, long and thick straight pipe fittings, short and thin single-bend pipe fittings, long and thin single-bend pipe fittings, short and thick single-bend pipe fittings, long and thick single-bend pipe fittings, short and thin double-bend vertical pipe fittings, long and thin double-bend vertical pipe fittings, short and thick double-bend vertical pipe fittings, long and thick double-bend vertical pipe fittings. According to the different lengths and thicknesses of the pipe fittings and the horizontal, vertical and curved characteristics of the pipeline path, the pipe fittings correspond to various types of metal pipe sound windows with different lengths, thicknesses and curved structures of the cylindrical pipe body, for users to choose and install independently according to the emotion or range of the musical instrument.

[0018] As a further improvement of the present invention, the flat cover sound window, in addition to its connection method with the rear end of the erhu sound box and the hollow engraved pattern of the sound window, the four-ring treble pressure-leveling sound window, the four-ring treble threaded flat cover sound window, the three-ring treble pressure-leveling sound window, the bass flat cover sound window and the sub-bass flat cover sound window have the same main structure as the traditional erhu sound window. When the all-metal sound boxes of the two structural types are respectively matched, combined, connected and installed with the flat cover sound windows, they can both be used as traditional erhu.

[0019] The all-metal sound box of the Erhu with multi-tone windows and transformable orchestral structure mainly includes the following five invention contents:

[0020] 1. The erhu full metal sound box of the utility model is a erhu full metal sound box in which the sound box, sound skin and sound window as well as special accessories such as the sound bar cover and the semi-hexagonal frame with a semi-hexagonal shape are all made of the same metal material (or stainless steel, copper, silver, etc.) with excellent properties such as strength, flexibility, sound absorption and chemical stability, and are made through organic combination.

[0021] 2. The erhu all-metal sound box of the utility model has two structural modes, one of which is a sound box with a built-in sound skin and a frame sound box, that is, the cylindrical sound box with a built-in sound skin and its built-in sound skin are single independent components of an integrated sound box made of the same metal material, and the transition between the entire sound skin at the front end of the sound box and the inner and outer circumferential edges of the sound box are integrated into one, without any connection and installation gaps, and the whole is complete and smooth, and the front end of the sound box with the built-in sound skin is fully closed; the other is a through-hole sound box structure, that is, the through-hole sound box and the sound skin are independent components made of the same metal material, and the inner cavity of the sound box is an overall through-hole shape. Among them, the through-hole sound box structure is divided into two types, one is a cylindrical through-hole frame sound box structure, and the sound box is a circular through-hole sound box, and the other is a hexagonal through-hole sound box structure, and the sound box is a hexagonal through-hole sound box.

[0022] 3. Two special parts, the neck sleeve and the semi-hexagonal frame, are organically combined with the full metal sound box. Among them, a small section of the neck sleeve with a through hole, which is similar in shape to the traditional erhu neck, is fixedly installed on the semi-hexagonal frame, which is approximately semi-hexagonal in shape. The semi-hexagonal frame is also fixedly installed horizontally on the round metal sound box as a whole, so that the upper part of the full metal sound box is basically similar in structure to the upper part of the traditional hexagonal erhu sound box. As a result, not only does the erhu neck no longer need to pass through the entire erhu sound box for fixed installation, but only a small section of the root neck of the original traditional erhu neck that is connected to the sound box needs to be cut off, and the rest of the traditional erhu neck is kept in its original state. Then, the root of the erhu neck that has been cut off and retained is directly inserted into the neck sleeve for tight fitting and fixed installation. Therefore, the inner cavity of the all-metal sound box completely eradicates the entire vertical upright neck that originally blocked the center source of the sound wave vibration of the sound box skin in the inner cavity of the traditional erhu sound box and passed through the entire sound box and was fixedly connected to the sound box. At the same time, due to the setting of the special parts of the semi-hexagonal frame with a semi-hexagonal shape, for users who are accustomed to using hexagonal or octagonal erhu sound boxes, when operating the bow on the cylindrical all-metal sound box, it has the automatic conversion function to still operate the bow on the hexagonal or octagonal erhu sound box.

[0023] 4. The finished all-metal sound box products made by the above two structural methods have the same main structure and main functions except for the structure of the sound box and the sound box skin connected to each other and the shape of the sound box. That is, all the components of the all-metal sound box are made of the same metal material, there is no sound bar in the sound box cavity, there are no connection holes and installation gaps in the sound box cavity wall, the sound box cavity metal wall surface is complete and smooth without any defects, the sound box cavity air column volume is the most complete and maximized, the oscillation and conduction of the sound resonance harmonics in the sound box resonance box are particularly full and smooth, and when bowing on the cylindrical all-metal sound box, it has the automatic conversion function of bowing on the hexagonal or octagonal erhu sound box, and all other structural features and functional characteristics are exactly the same.

[0024] 5. The sound window located at the rear end of the all-metal sound box is changed from the traditional permanently fixed installation structure to a convenient installation structure that can be adjusted and transformed between multiple sound windows with independent functions. That is, the user can match, transform and select any independent sound window among the multiple sound windows with independent functions according to the needs of the music emotion or range, and conveniently connect and combine them with the rear end of the all-metal sound box. After the metal sound box is closely matched and combined with each independent sound window, each independent sound window presents its own unique oscillation characteristics and conduction paths for the resonance harmonics of the sound in the sound box cavity. The multi-sound windows of the utility model are divided into three types: tube sound windows, flat cover sound windows and flat cover tube sound windows. Among them, tube sound windows and flat cover tube sound windows are collectively referred to as metal tube sound windows.

[0025] The metal tube sound windows all have the main structural modeling characteristics of the cylindrical tube body of a wind instrument. The tube body is an overall fully enclosed structure. The length, thickness, and straightness of the tube body can all be improved and processed accordingly based on the sound effects actually transmitted by the metal tube sound windows. This allows the production of various types of metal tube sound windows with the structural modeling characteristics of wind instruments and in various shapes for users to adjust, change, and select for use. When the metal tube sound window with an overall fully enclosed structure is tightly connected and assembled with the rear end of the all-metal sound box, the air column in the inner cavity of the all-metal sound box and the air column in the inner cavity of the metal tube sound window pipeline are interconnected and integrated. At the same time, the sound outlet of the fully enclosed metal tube sound window becomes the only common air outlet and sound outlet for the inner cavity of the all-metal sound box and the inner cavity of the metal tube sound window pipeline and the outside world. The resonant harmonics of the piano sound in the resonance box of the all-metal sound box naturally follow the guidance of the inner cavity path of the metal tube sound window, which may be thick, thin, long, short, straight, curved, horizontal or vertical, etc., of each independent functional metal tube sound window, and are concentratedly conducted to the outside world through the only sound outlet of the metal tube sound window. Thus, the main structure of the erhu sound box of the stringed instrument is organically integrated with the cylindrical tubular structure characteristics of the wind instrument. When the resonance harmonics of the sound appear in the inner cavity of the sound box, the oscillation and conduction of the resonance harmonics are also changed along with the changes in the pipe conduction paths of the metal tube sound windows of different shapes. This makes the resonance box of the all-metal sound box, while transmitting the unique sound of the erhu stringed instrument, naturally integrate the partial range characteristics of the wind instrument, which are either slight or obvious, along with the pipe conduction paths of the metal tube sound windows of different shapes. Therefore, when the all-metal sound box of the present invention is matched, combined, connected and installed with the various types of metal tube sound windows of the present invention, it is organically combined into a new type of structure with multiple sound windows and transformable erhu sound box with erhu stringed instruments as the main instrument and wind instruments as the auxiliary instrument, and the string instruments and wind instruments are compatible and durable.

[0026] In addition, the utility model has a flat cover sound window among the independent multi-sound windows. Except for the combination connection installation method with the rear end of the full metal sound box and the partial hollow carved pattern of the sound window, which is different from the traditional erhu sound window, the main structure of the traditional erhu sound window is basically retained, so that the full metal sound box of the utility model can not only be used as an integrated string and string erhu, but also can be used as a traditional erhu after changing and selecting the combination installation of the flat cover sound window. Therefore, the full metal sound box of the multi-sound window of the utility model with a transformable integrated string and string erhu has the dual-purpose functional characteristics of taking both the integrated string and string erhu and the traditional erhu into consideration.

[0027] The structural features and functional characteristics of the three types of metal sound windows of the utility model, namely, the tube sound window, the flat cover sound window and the flat cover tube sound window, which have independent functions, are as follows:

[0028] (1) Tube Sound Window

[0029] The pipe sound window is composed of two parts: the sound window base and the pipe fitting. The middle part of the sound window base is a conical arc tube, and its front and rear ends are cylindrical tubular bodies with significantly different thicknesses. The combination connection and installation methods of the front end of the sound window base and the all-metal sound box are divided into two connection and installation methods: press fitting and threaded connection and installation methods, while the combination connection and installation method of the rear end of the sound window base and the pipe fitting is only a press fitting connection and installation method. According to the length, thickness, and the straightness of the pipe path of the main structural modeling characteristics of the cylindrical tube body of the wind instrument possessed by the pipe fitting, there are 12 types of pipe fittings:

[0030] 1. Short and thin straight pipe accessories 2. Long and thin straight pipe accessories

[0031] 3. Short thick straight pipe accessories 4. Long thick straight pipe accessories

[0032] 5. Short thin single elbow pipe accessories 6. Long thin single elbow pipe accessories

[0033] 7. Short and thick single elbow pipe accessories 8. Long and thick single elbow pipe accessories

[0034] 9. Short and thin double-bend vertical pipe accessories 10. Long and thin double-bend vertical pipe accessories

[0035] 11. Short thick double bend vertical pipe accessories 12. Long thick double bend vertical pipe accessories

[0036] If we ignore the press-fit and threaded connection installation methods of the tube sound window and the rear port of the all-metal sound box and the factors such as the short and thin, long and thin, short and thick, and long and thick tube accessories, the tube sound window can be combined and simplified into the following 4 types:

[0037] 1. Straight tube sound window: a straight tube fitting that is connected and installed in combination with the center of the outside of the sound window base (towards the external space of the all-metal sound box). Its cylindrical tube body is composed of a section of straight tube. The piano sound resonance harmonics generated in the resonance box of the all-metal sound box travel parallel to the inner cavity of the straight tube fitting installed parallel to the horizontal center line of the all-metal sound box, and are directed toward the only terminal sound outlet in the inner cavity of the straight tube fitting, and are concentratedly conducted to the external space.

[0038] 2. Single-bend vertical pipe sound window: a single-bend pipe accessory that is connected and installed in combination with the center of the outer side of the sound window base. It is composed of a pipe elbow and a straight pipe connected to it. At the same time, the pipe elbow end of the single-bend pipe accessory is directly connected and installed in combination with the sound window base. The piano sound resonant harmonics in the resonance box of the all-metal piano sound box first turn in an arc shape in the pipe cavity of the single-bend vertical pipe sound window, then go straight vertically through the path of the straight pipe cavity perpendicular to the horizontal center line of the all-metal piano sound box, and then head toward the only terminal sound outlet of the single-bend pipe accessory cavity, and are concentratedly conducted to the outside space.

[0039] 3. Single-bend horizontal tube sound window: Its composition is exactly the same as that of the single-bend vertical tube sound window. The only difference is that the straight tube end of the single-bend tube accessory is directly connected and installed horizontally with the sound window base to form a single-bend horizontal tube sound window. The piano sound resonant harmonics in the resonance box of the all-metal sound box first go straight through a straight tube cavity parallel to the horizontal center line of the all-metal sound box in the pipe cavity of the single-bend horizontal tube sound window, and then make a circular arc turn, and pass through the only terminal sound outlet in the cavity of the single-bend tube accessory, and are concentratedly transmitted to the outside space.

[0040] 4. Double-bend vertical pipe sound window: a double-bend vertical pipe accessory that is connected and installed in combination with the center of the outer side of the sound window base. It consists of three parts: two pipe elbows and a straight pipe connected between the two pipe elbows. One of the pipe elbows is directly connected and installed in combination with the sound window base. The resonant harmonics of the piano sound in the resonance box of the all-metal piano sound box first make an arc-shaped turn in the inner cavity of the double-bend vertical pipe sound window, then go vertically through a straight pipe inner cavity perpendicular to the horizontal center line of the all-metal piano sound box, and finally make another arc-shaped turn, and pass through the only terminal sound outlet in the inner cavity of the double-bend vertical pipe accessory, and are concentratedly transmitted to the outside space.

[0041] (2) Flat soundproof window

[0042] The flat cover sound window is basically the same as the main structure of the traditional erhu sound window, except for the connection method with the rear end of the erhu sound tube and the hollow carved pattern of the sound window. The main purpose of setting the flat cover sound window is to retain the basic structural characteristics of the appearance of the traditional erhu sound window. That is, when the rear end of the all-metal sound tube of the utility model is replaced with the flat cover sound window, it can still be used as a traditional erhu, so that the utility model has the dual-purpose functional characteristics of being used as both an orchestral erhu and a traditional erhu.

[0043] According to the connection mode between the flat cover sound window and the rear port of the erhu all-metal sound box of the utility model and the hollow carved patterns of the sound windows, the flat cover sound windows are mainly divided into the following 8 types:

[0044] 1. Four-ring treble pressure-balanced sound cover window 2. Four-ring treble thread-fastened sound cover window

[0045] 3. Three-ring treble pressure-balanced sound cover window 4. Three-ring treble thread-fastened sound cover window

[0046] 5. Bass pressure leveling sound cover window 6. Bass thread leveling sound cover window

[0047] 7. Subwoofer pressure-matched sound cover window 8. Subwoofer threaded flat sound cover window

[0048] If we ignore the press-fit and threaded connection between the flat cover sound window and the rear port of the erhu all-metal sound box, the flat cover sound window can be combined and simplified into the following 4 types:

[0049] 1. Four-ring treble flat cover sound window: that is, the hollow carved pattern on the central circumference of the sound window is composed of four similar geometric figures with successively smaller areas, and four evenly distributed circular hollow carved patterns.

[0050] 2. Three-ring treble pressure-balancing sound cover window: It is composed of three circular hollow carved patterns with three different geometric shapes evenly distributed.

[0051] The above-mentioned four-ring or three-ring flat cover sound windows are all treble sound windows made by appropriately increasing the carved hollow area of ​​the center and circumference of the flat cover sound window in order to enhance the conduction characteristics of the harmonics of the piano sound in the resonance box of the metal sound box.

[0052] 3. Bass flat-cover sound window: A bass sound window made by appropriately reducing the carved and hollowed-out area of ​​the center and circumference of the sound window to meet the special needs of transmitting deep and rich musical sounds, or by reducing the carved and hollowed-out area of ​​the circumferential edge of the sound window while completely closing the center of the sound window.

[0053] 4. Subwoofer flat sound window: a fully enclosed flat sound window without any hollow carved patterns. The sound of the all-metal erhu with a subwoofer flat sound window can be significantly reduced, while at the same time, it can clearly transmit the real sound of the erhu without any distortion of the timbre, which is better than the erhu mute commonly used at present.

[0054] (3) Flat cover pipe sound window

[0055] The flat-covered tube sound window is the third type of sound window in the utility model of convertible multi-sound windows, which is made by combining the structural features of the above two types of tube sound windows and flat-covered sound windows. The flat-covered tube sound window is composed of two parts: the flat-covered tube sound window base and the tube fittings. The tube fittings are exactly the same as the various types of tube fittings that make up the components of the aforementioned tube sound window. Compared with the sound window base in the tube sound window, the flat-covered tube sound window base has no essential difference from the tube sound window base, except that it completely lacks the conical arc tubular structural features of the sound window base, and after being tightly connected to the rear end of the all-metal sound box, the resonant harmonics of the inner cavity of the all-metal sound box are slightly different in the conduction level and path toward the entrance of the tube fitting pipeline from the tube sound window.

[0056] If we ignore the two combined connection installation methods of press-fit and threaded connection between the front end of the flat cover pipe sound window base and the rear end of the all-metal sound box, there are 4 types of flat cover pipe sound window bases:

[0057] 1. Press the capillary tube to level the cover tube sound window base.

[0058] 2. Press the thick pipe to level the cover pipe sound window base.

[0059] 3. Thick tube threaded flat cover tube sound window base.

[0060] 3. Thin tube threaded flat cover tube sound window base.

[0061] When the above four types of flat-covered pipe sound window bases are matched and connected with various pipe fittings with different structural characteristics such as thickness, length, single bend and double bend, the flat-covered pipe sound window also has various types similar to the pipe sound window, such as:

[0062] 1. Short thin pressure leveling cover double curved vertical pipe sound window. It is composed of short thin double curved vertical pipe accessories and thin pipe pressure leveling cover pipe sound window base press fitting connection installation combination.

[0063] 2. Long and thick pressure-matched straight pipe sound window. It is composed of a long and thick straight pipe fitting and a thick pipe pressure-matched cover pipe sound window base.

[0064] 3. Short thick threaded flat cover single bend vertical pipe sound window. It is composed of short thick single bend pipe fittings and thick pipe threaded flat cover pipe sound window base vertically pressed and connected.

[0065] 4. Short thin thread flat cover single bend horizontal pipe sound window. It is composed of short thin single bend pipe fittings and thin tube thread flat cover pipe sound window base horizontally press-fitted and installed.

[0066] Therefore, there is no essential difference between the flat-covered tube sound window and the aforementioned tube sound window, except for the shape structure of the sound window base and the slightly different conduction characteristics of the piano sound resonance harmonics in the inner cavity of each sound box toward the entrance of the tube fitting pipe after the two are respectively connected to the rear end of the all-metal sound box. When the flat-covered tube sound window with a fully enclosed structure is tightly connected and installed in combination with the rear end of the all-metal sound box, the cylindrical tubular structural features of the wind instrument are also organically integrated into the main structure of the sound box of the string instrument erhu, and the air column in the inner cavity of the all-metal sound box and the air column in the inner cavity of the flat-covered tube sound window pipe are also interconnected and integrated, and the sound outlet of the fully enclosed flat-covered tube sound window becomes the only common connection between the inner cavity of the all-metal sound box and the inner cavity of the flat-covered tube sound window pipe and the outside space. With one air outlet and a single sound outlet, when the resonance harmonics of the piano sound appear in the resonance box of the all-metal sound box, the oscillation and conduction characteristics of the resonance harmonics will also change with the changes in the conduction paths of the flat-covered tube sound windows, such as thick, thin, long, short, straight, curved, horizontal, vertical, etc., in the inner cavity of the pipe. Similarly, after the flat-covered tube sound windows are matched, combined, connected and installed with the all-metal sound box of the utility model, they also form the multi-tone window, transformable orchestral-integrated erhu all-metal sound box of the utility model.

[0067] In summary, the two structural forms of the all-metal sound box of the utility model, except for the transitional connection between the sound box and the sound skin and the different sound box shapes, all its components are made of the same metal material, there is no neck in the sound box cavity, there are no connecting holes and installation gaps in the inner wall of the sound box cavity, the metal wall surface of the inner wall of the sound box cavity is smooth and flawless, the volume of the air column in the sound box cavity is the most complete and maximized, the oscillation and conduction of the resonance harmonics of the sound of the piano in the resonance box of the sound box cavity are particularly sufficient and smooth, and when bowing on the round metal sound box, it has the automatic conversion function of still bowing on the hexagonal or octagonal erhu sound box, and the metal sound window at the rear end of the sound box and the various types of functional metal sound windows of the utility model, and the convenient connection and installation that can realize independent adjustment and transformation with each other, all of which are exactly the same. At the same time, the two structural types of all-metal sound boxes, when matched, combined, connected and installed with various types of metal tube sound windows, are organically combined into an integrated string and orchestra erhu; and when the two structural types of all-metal sound boxes, when matched, combined, connected and installed with various types of metal flat-cover sound windows, can also be used as a traditional erhu, so that the utility model has the dual functional characteristics of being used as an integrated string and orchestra erhu and as a traditional erhu.

[0068] Thus, the utility model is produced, which is mainly composed of erhu string instruments and supplemented by wind instruments, and the new structure of string instruments and wind instruments is compatible with each other and durable, with multi-tone windows and transformable orchestral integrated erhu full-metal sound box. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a front view of the utility model when the structure of the piano tube 7 with its own piano skin frame is selected.

[0070] Figure 2 yes Figure 1 Left view of .

[0071] Figure 3 yes Figure 1 Top view of the .

[0072] Figure 4 yes Figure 2 AA cross-section diagram.

[0073] Figure 5 It is a front view of the utility model when the through-hole frame piano tube 8 structure is selected.

[0074] Figure 6 yes Figure 5 Left view of .

[0075] Figure 7 yes Figure 5 Top view of the .

[0076] Figure 8 yes Figure 6 BB cross-section diagram.

[0077] Fig. 9 It is a front view of the utility model when the hexagonal through-hole piano tube 31 structure is selected.

[0078] Fig.10 yes Fig. 9 Left view of .

[0079] Fig.11 yes Fig. 9 Top view of the .

[0080] Fig.12 yes Fig.10 CC cross-section diagram.

[0081] Fig.13 yes Figure 1 A single-row front view of the assembly of the piano rod sleeve 1 and the first half hexagonal frame 5 and other two components.

[0082] Fig.14 yes Fig.13 Left view of .

[0083] Fig.15 yes Fig.13 Top view of the .

[0084] Fig.16 yes Fig.14 DD cross-section diagram.

[0085] Fig.17 Is to be inserted Fig.18 The piano bar cover 1 must be matched with the single-row front view of the erhu piano bar 26 before being connected and installed.

[0086] Fig.18 yes Figure 1 A single-row front view of the piano bar cover 1.

[0087] Fig.19 yes Fig.17 EE cross-section diagram.

[0088] Fig. 20 yes Fig.18 FF cross-section diagram.

[0089] Fig.21 The erhu pole 26, the pole sleeve 1 and the first half hexagonal frame 5 are assembled and installed together with the Figure 4 The corresponding exploded single-column AA section view.

[0090] Fig. 22 yes Fig.21 Top view of the .

[0091] Fig.23 yes Figure 5A single-row front view of the combined installation of the three components including the neck cover 1, the second semi-hexagonal frame 6 and the semi-hexagonal pressing plate 11.

[0092] Fig.24 yes Fig.23 Left view of .

[0093] Fig.25 yes Fig.23 Top view of the .

[0094] Fig.26 yes Fig.24 GG cross-section diagram.

[0095] Fig. 27 yes Figure 5 Figure, 6 Figure, Figure 7 and Figure 8 A single row front view of the middle half hexagonal pressing piece 11.

[0096] Fig.28 yes Fig. 27 Left view of .

[0097] Fig.29 yes Fig. 27 Top view of the .

[0098] Fig.30 yes Fig. 27 HH cross-section diagram.

[0099] Fig.31 yes Figure 4 The exploded single-row AA cross-sectional view of the piano tube 7 with its own piano skin frame, the thin tube threaded sound window base 20 and the short thin double curved vertical pipe fitting 21, etc., which are matched and connected and installed. Among them, the thin tube threaded sound window base 20 and the short thin double curved vertical pipe fitting 21 are combined into a short thin double curved vertical pipe sub-sound window after matching, connecting and installing.

[0100] Fig.32 When the utility model adopts a through-hole frame sound box 8, the through-hole frame sound box 8 is matched with the thin tube pressure dubbing window base 24 and the short thin double-bend vertical pipe fitting 21 and other three parts to be connected and installed, and correspond to Figure 8 The single row exploded BB cross-sectional view of the embodiment of the present invention. Among them, the thin tube pressure dubbing window base 24 and the short thin double curved vertical pipe fitting 21 are matched, connected and installed to form a short thin double curved vertical pipe sub-sound window.

[0101] Fig.33 is with Figure 4 The corresponding self-skin frame sound box 7 is an exploded single-row AA cross-sectional view when it is matched, connected and installed with the four-ring treble threaded flat cover sound window 25.

[0102] Fig.34 is with Figure 8The corresponding through-hole frame sound box 8 is an exploded single-row BB cross-sectional view when it is connected and installed in conjunction with the four-ring high-pitched pressure-balancing sound cover window 23.

[0103] Fig.35 It is a front view of the short and thin double-bend vertical pipe fitting 21.

[0104] Fig.36 yes Fig.35 Left view of .

[0105] Fig.37 It is a front view of the slender double-bend vertical pipe fitting 28.

[0106] Fig.38 yes Fig.37 Left view of .

[0107] Fig.39 The present invention is a schematic diagram of the structure of a short thin single curved vertical pipe sound window, which is composed of a short thin single curved pipe fitting 29 and a thin pipe threaded sound window base 20 which are vertically connected and installed.

[0108] Fig.40 The present invention is a schematic diagram of the structure of a short thin single curved transverse tube sound window, which is composed of a short thin single curved tube fitting 29 and a thin tube threaded sound window base 20 which are horizontally connected and installed.

[0109] Fig.41 It is a front view of the short thin single elbow pipe fitting 29 when placed horizontally.

[0110] Fig.42 yes Fig.41 Left view of .

[0111] Fig.43 The invention is a schematic diagram of the structure of a long thin single curved vertical tube sound window, which is composed of a long thin single curved tube fitting 30 and a thin tube threaded sound window base 20 which are vertically connected and installed.

[0112] Fig.44 The invention is a schematic diagram of the composition structure of a long and thin single curved horizontal tube sound window, wherein the tube sound window is composed of a long and thin single curved tube fitting 30 and a thin tube threaded sound window base 20 which are horizontally connected and installed.

[0113] Fig.45 It is a front view of the slender single elbow pipe fitting 30 when placed horizontally.

[0114] Fig.46 yes Fig.45 Left view of .

[0115] Fig.47 It is a single-row front view of a short, thick, single-bend vertical pipe sound window, which is composed of a thick pipe threaded sound window base 32 and a short, thick, single-bend pipe fitting 33 connected and installed.

[0116] Fig.48 yes Fig.47 Right view of .

[0117] Fig.49 yes Fig.47 Left view of .

[0118] Fig.50 yes Fig.47 Top view of the .

[0119] Fig.51 yes Fig.49 KK cross-section diagram.

[0120] Fig.52 It is a single-row front view of a long thick double-bend vertical pipe sound window, which is composed of a thick pipe pressure dubbing window base 35 and a long thick double-bend vertical pipe fitting 36 connected and installed.

[0121] Fig.53 yes Fig.52 Left view of .

[0122] Fig.54 yes Fig.53 Exploded single row MM cross-section of the medium thick tube dubbing window base 35.

[0123] Fig.55 It is a single-row front view of a long thick straight tube sound window, which is composed of a thick tube pressure dubbing window base 35 and a long thick straight tube fitting 37 connected and installed.

[0124] Fig.56 yes Fig.55 Left view of .

[0125] Fig.57 It is a single-row front view of the four-ring high-frequency pressure-balancing sound-covering window 23.

[0126] Fig.58 yes Fig.57 Left view of .

[0127] Fig.59 yes Fig.57 NN profile diagram.

[0128] Fig.60 yes Fig.57 Schematic diagram of the sound window carving and hollowing processing, among which, all the blank areas in the hollow carving geometric figures are the areas that are removed during the hollow carving processing.

[0129] Fig.61 It is a front view of the three-ring high pitch flat cover sound window 38 (Special note: whether it is a threaded flat cover sound window or a press-fit flat cover sound window, the front view of the three-ring high pitch flat cover sound window is the same as Fig.61 are exactly the same).

[0130] Fig.62 yes Fig.61 Schematic diagram of the hollow carving processing of the sound window. In the figure, all the blank areas in the hollow carving geometric figures are the areas that are removed during the hollow carving processing.

[0131] Fig.63 It is a front view of the bass flat cover sound window 39 (Special note: Whether it is a threaded flat cover sound window or a press-fit flat cover sound window, the front view of the bass flat cover sound window is the same as Fig.63 are exactly the same).

[0132] Fig.64 yes Fig.63 Schematic diagram of the hollow carving processing of the sound window. In the figure, all the blank areas in the hollow carving geometric figures are the areas that are removed during the hollow carving processing.

[0133] Fig.65 It is a front view of the subwoofer flat cover sound window 40 (Special note: Whether it is a threaded flat cover sound window or a press-fit flat cover sound window, the front view of the subwoofer flat cover sound window is the same as Fig.65 are exactly the same).

[0134] Fig.66 It is a schematic diagram of the fully enclosed structure of the subwoofer flat cover sound window 40 without any hollowing and carving processing or removal of the part.

[0135] Fig.67 The short thin pressure leveling cover double curved vertical pipe sound window is formed by connecting and combining the thin tube pressure leveling cover pipe sound window base 41 and the short thin double curved vertical pipe fitting 21, and corresponds to Fig.57 NN profile diagram.

[0136] Fig.68 It is a plan view of a long thick pressure-balanced cover straight pipe sound window which is formed by connecting and assembling a thick pipe pressure-balanced cover pipe sound window base 42 and a long thick straight pipe fitting 37 .

[0137] Fig.69 The short thick threaded flat cover single bend vertical pipe sound window is composed of a thick tube threaded flat cover pipe sound window base 43 and a short thick single bend pipe fitting 33 connected and combined, and corresponds to Fig.49 KK cross-section diagram.

[0138] Fig.70 The schematic plan view of a short thin thread flat cover single bend horizontal tube sound window is formed by connecting and assembling a thin tube thread flat cover tube sound window base 44 and a short thin single bend tube fitting 29.

[0139] In the figure: 1. Piano neck sleeve 2. Piano neck sleeve upper fixing hole 3. Piano neck sleeve lower fixing hole 4. Piano neck sleeve base weld 5. Semi-hexagonal frame 6. Semi-hexagonal frame (for through-hole frame piano sound box 8) 7. Self-contained piano skin frame piano sound box (a single independent component of an integrated metal piano sound box made of the same metal material as the piano skin a) 8. Through-hole frame piano sound box (an independent component of each piano skin 9) 9. Piano skin 10. Piano skin edging 11. Semi-hexagonal pressing piece 12. Semi-hexagonal frame outer weld 13. Semi-hexagonal frame inner weld 14. Piano support fixing inner column 15. Piano support fixing inner column weld 16. Piano support fixing outer column 17. Piano support fixing outer column weld 18. Metal The outer thread of the rear port of the piano tube 19, the inner thread of the sound window connecting port 20, the thin tube thread sound window base 21, the short thin double-bend vertical pipe accessories (matched and connected with the thin tube thread sound window base 20 or the thin tube pressure dubbing window base 24, both can be combined into a short thin double-bend vertical pipe sub-sound window) 22, the tube sound window outlet 23, the four-ring treble pressure leveling cover sound window 24, the thin tube pressure dubbing window base 25, the four-ring treble thread flat cover sound window 26, the erhu pole 27, the root of the erhu pole 28, the long thin double-bend vertical pipe accessories (matched and connected with the thin tube thread sound window base 20 or the thin tube pressure dubbing window base 24, both can be combined into a long thin double-bend vertical pipe sub-sound window) 29, the short Thin single curved tube accessories (connected and installed with the thin tube threaded sound window base 20 or the thin tube pressure dubbing window base 24, both can be combined into a short thin single curved vertical tube sub-sound window or a short thin single curved horizontal tube sub-sound window) 30, long thin single curved tube accessories (connected and installed with the thin tube threaded sound window base 20 or the thin tube pressure dubbing window base 24, both can be combined into a long thin single curved vertical tube sub-sound window or a long thin single curved horizontal tube sound window) 31, hexagonal through-hole piano tube 32, thick tube threaded sound window base 33, short thick single curved tube accessories (connected and installed with the thick tube threaded sound window base 32 or the thick tube pressure dubbing window base 35, both can be combined into a short thick single curved vertical tube sub-sound window) 34, rear end of metal piano tube Mouth connection sleeve 35, thick tube pressure dubbing window base 36, long thick double-bend vertical pipe accessories (matched and connected with the thick tube threaded sound window base 32 or the thick tube pressure dubbing window base 35, both can be combined into a long thick double-bend vertical pipe sub-sound window 37, long thick straight pipe accessories (matched and connected with the thick tube threaded sound window base 32 or the thick tube pressure dubbing window base 35, both can be combined into a long thick straight tube sub-sound window) 38, three-ring treble flat cover sound window 39, bass flat cover sound window 40, sub-bass flat cover sound window 41, thin tube pressure matching cover pipe sub-sound window base 42, thick tube pressure matching cover pipe sound window base 43, thick tube threaded flat cover pipe sound window base 44, thin tube threaded flat cover pipe sound window base

[0140] Special note:

[0141] a. Piano skin: The piano skin a and the piano body 7 with its own piano skin frame are made of the same piece of metal material and are a single independent component of the overall integrated piano body. DETAILED DESCRIPTION

[0142] The specific implementation of the utility model is now described as follows in conjunction with the accompanying drawings:

[0143] The utility model has two structural modes of the all-metal sound box. One is the sound box structure with its own sound skin frame. Figure 4 As shown in the figure, the self-skin frame sound box 7 and its self-skin a are made of the same piece of metal material to form a single independent component of the whole integrated sound box; the other is a through-hole frame sound box structure. Among them, the through-hole frame sound box structure is divided into two types, one is as follows Figure 8 The through-hole frame sound box 8 shown in the figure, the other is as shown in the figure Fig.12 The hexagonal through-hole sound box 31 shown. The finished all-metal sound box made by the above two structural methods has basically the same main structure and functional characteristics, except for the structure of the connection between the sound box and the sound skin and the shape of the sound box. All the components of the all-metal sound box are made of the same metal material with excellent strength, flexibility, sound absorption and chemical stability. According to the characteristics of the above-mentioned all-metal sound box with two different structural methods, the specific implementation methods of the utility model have the following five items:

[0144] 1. If the Erhu full metal sound box of the utility model adopts the sound box structure with its own sound skin frame, then Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown (Note: they are respectively the front view, left view, top view and AA cross-sectional view of the utility model of the multi-tone window transformable orchestral erhu full metal sound box when the self-attached sound box frame sound box 7 is selected), it is mainly composed of a neck sleeve 1, a first semi-hexagonal frame 5, a self-attached sound box frame sound box 7, a sound box support fixed inner column 14, a sound box support fixed outer column 16 and a metal sound window (here is a short and thin double-bend vertical tube sound window, composed of a thin tube threaded sound window base 20 and a short and thin double-bend vertical tube accessory 21) and other components in combination and installation, wherein the metal sound window short and thin double-bend vertical tube sound window can be conveniently adjusted and transformed with other types of metal sound windows equipped with the utility model. All of the above components are made of the same metal material such as stainless steel, copper, silver, etc. Among them, the self-attached sound box frame sound box 7 and its own sound box a, as shown Figure 4 AA section diagram and Fig.31 and Fig.33 As shown in the single-row AA cross-section, it is a single independent component of the integral integrated sound box made of the same piece of metal material.

[0145] Second, select the piano rod cover 1 and the first half hexagonal frame 5 in the structure of the piano skin frame 7, such as Fig.13 , Fig.14 , Fig.15 and Fig.16 As shown, they are respectively from Figure 1 , Figure 2 , Figure 3 and Figure 4 The front view, left view, top view and the left view of the piano rod cover 1 and the first half hexagonal frame 5 are shown in the figure. Figure 4 The AA profile corresponds to a single column Fig.14 DD cross-sectional view, in which the base of the piano neck cover 1 and the first half hexagonal frame 5 are directly welded and connected according to the position shown by the weld 4 of the piano neck cover base.

[0146] In addition, the erhu pole connected and installed with the pole sleeve 1 is completely the same as the traditional erhu pole except for the shape and length of its root. Fig.17 , Fig.18 , Fig.19 , Fig. 20 , Fig.21 ,and Fig. 22 As shown, the elliptical outer diameter of the erhu pole 26 used in the present invention is exactly the same as the elliptical outer diameter of the pole sleeve 1, and the elliptical outer diameter of the erhu pole root 27 is slightly smaller than the elliptical inner diameter of the pole sleeve 1, so that the erhu pole root 27 can be adjusted according to the Fig.17 and Fig.19 Direction shown, smooth insertion with tight fit throughout Fig.18 and Fig. 20 The erhu pole root 27 is firmly connected and installed with the pole sleeve 1 through the upper fixing hole 2 and the lower fixing hole 3 of the pole sleeve. Fig.21 As shown in the figure, the erhu pole root 27 is completely inserted into the pole sleeve 1 and assembled and connected with the first half hexagonal frame 5, corresponding to Figure 4 The exploded single-row AA section view of the three-component combined connection installation, Fig. 22 yes Fig.21 The erhu pole 26 shown in the above figure is completely identical to the traditional erhu pole except for the length and outer diameter of the pole root 27.

[0147] In summary, due to the installation combination of the neck sleeve 1 and the first semi-hexagonal frame 5, the erhu neck used in the utility model no longer needs to be fixedly installed through the built-in sound skin frame sound box 7, and the specific upper and lower vertical parts of the full metal sound box no longer need to be drilled. The traditional erhu sound box cavity originally blocked the central source of the sound wave vibration of the sound skin at a close distance, and the entire vertical upright neck that passed through the entire sound box and was fixedly connected and installed with the sound box, has also been completely eradicated in the full metal sound box cavity of the utility model. Therefore, the utility model adopts the all-metal sound box with its own sound box skin frame sound box 7 structure. The metal sound box inner cavity has no sound bar. The whole metal inner wall of the inner cavity, including the transition part where the whole sound box skin at the front end of the sound box is integrated with the inner and outer edges of the sound box circumference, does not have any connecting installation gaps, installation holes or any other wall defects. The whole is complete and smooth. The volume of the air column in the resonance box of the metal sound box reaches the most complete and maximized level, and the oscillation and conduction of the resonance harmonics of the piano sound in the resonance box of the metal sound box are more complete and smooth.

[0148] Among them, the setting of the first semi-hexagonal frame 5 not only facilitates the firm positioning and installation of the neck cover 1, so that the erhu neck no longer needs to pass through the erhu sound box for fixed installation, but also makes the top of the circular self-skin frame sound box 7 have the structural characteristics of the hexagonal sound box. Therefore, for users who are accustomed to using hexagonal or octagonal sound boxes, when operating the erhu product using the circular self-skin frame sound box 7, all the user's original operating skills and operating habits on the hexagonal or octagonal sound box can still be fully retained.

[0149] 3. If the erhu full metal sound box of the utility model adopts the circular through-hole frame sound box 8 structure, then, Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown (Note: they are the front view, left view, top view and BB cross-section view of the utility model of the multi-tone window transformable orchestral erhu full metal sound box when the through-hole frame sound box 8 is selected), it is mainly composed of the neck sleeve 1, the second semi-hexagonal frame 6, the through-hole frame sound box 8, the sound box skin 9, the semi-hexagonal pressing plate 11, the inner column 14 of the sound box support, the outer column 16 of the sound box support and the metal sound window (here is the four-ring high-pitched pressure-leveling sound window cover 23) and other components. Similarly, the metal sound window four-ring high-pitched pressure-leveling sound window cover 23 can be conveniently adjusted and transformed with other types of metal sound windows equipped in the utility model.

[0150] At the same time, the above components are all made of the same metal material such as stainless steel, copper, silver, etc. in the same way as the structure of the built-in piano skin frame and piano box 7 (Note: the semi-hexagonal pressing piece 11 can be made of plastic material in addition to metal material).

[0151] Compared with the embodiment of the through-hole frame sound box 8 selected in the present invention and the embodiment of the self-skinned frame sound box 7, the main structures, assembly and installation methods and functions of the two embodiments are basically the same, and the differences between the two are the following two points:

[0152] 1. If Figure 8 As shown, the through-hole frame sound box 8 and the sound skin 9 are independent components respectively. Among them, the sound skin 9, in addition to being made of the same metal material as the metal sound box, can also be made of traditional natural leather membrane or artificial leather membrane.

[0153] 2. If Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, the semi-hexagonal pressing plate 11 is press-fitted on the through-hole frame sound box 8 in parallel with the second semi-hexagonal frame 6. At the same time, it is also press-fitted separately on the part of the sound box skin 9 at the edge 10. This part is also the support point for the bow hair and the strings to rub against each other at the front end of the sound box when the bow is moving. Therefore, the edge section of the sound box skin edge 10 at this part can be effectively protected by the semi-hexagonal pressing plate 11. The single-row front view, left view, top view and GG cross-sectional view of the semi-hexagonal pressing plate 11, the second semi-hexagonal frame 6 and the sound box neck cover 1 and other three parts are connected and installed as a whole, as shown in FIG. Fig.23 , Fig.24 , Fig.25 and Fig.26 As shown (can also refer to Figure 5 , Figure 6 , Figure 7 and Figure 8 ). Among them, the single-row front view, left view, top view and HH cross-sectional view of the semi-hexagonal pressing sheet 11 are as follows: Fig. 27 , Fig.28 , Fig.29 and Fig.30 As shown. Due to the arrangement of the semi-hexagonal pressing sheet 11, the horizontal length dimension of the second semi-hexagonal frame 6 is slightly smaller than the horizontal length dimension of the first semi-hexagonal frame 5 equipped in the embodiment of the self-contained piano skin frame piano tube 7. In addition, the basic structure and function of the second semi-hexagonal frame 6 and the first semi-hexagonal frame 5 are exactly the same, as shown. Figure 5 , Figure 6 , Figure 7 and Figure 8As shown, the semi-hexagonal pressing plate 11 and the second semi-hexagonal frame 6 are installed in parallel on the through-hole frame sound box 8. Therefore, the top of the circular through-hole frame sound box 8 also has the structural characteristics of a hexagonal sound box. For users who are accustomed to using hexagonal or octagonal sound boxes, when operating an erhu product using a circular through-hole frame sound box 8, it is exactly the same as when operating an erhu product using a circular self-skin frame sound box 7. All the user's original operating skills and operating habits on the hexagonal or octagonal sound box can still be fully retained.

[0154] In summary, except for the above two differences, the full metal sound box with a through-hole frame sound box 8 structure selected by the present invention has no neck in the inner cavity of the metal sound box, and the inner wall of the sound box is free of any connecting and installing holes and installing gaps. The metal wall surface of the inner cavity of the sound box is complete and smooth without any defects, the volume of the air column in the inner cavity of the sound box is the most complete and maximized, the oscillation and conduction of the resonance harmonics of the sound of the piano in the resonance box of the sound box are particularly sufficient and smooth, and when the bow is operated on the round metal sound box, it has an automatic conversion function that can still be performed on the hexagonal or octagonal erhu sound box, and the metal sound window at the rear end of the metal sound box and other types of functional metal sound windows equipped in the present invention can be adjusted and transformed with each other for convenient connection and installation, and other structural features and functions are exactly the same as the structure of the frame sound box 7 with its own sound box skin.

[0155] 4. If the all-metal sound box of the Erhu of the present invention adopts the structure of the hexagonal through-hole sound box 31 embodiment, then, Fig. 9 , Fig.10 , Fig.11 and Fig.12 As shown (Note: they are the front view, left view, top view and CC cross-sectional view of the utility model of the multi-tone window transformable orchestral erhu all-metal sound box when the hexagonal through-hole sound box 31 is used), it is mainly composed of a neck sleeve 1, a sound box skin 9, a sound box skin edging 10, a hexagonal through-hole sound box 31, a sound box support fixed inner column 14, a sound box support fixed outer column 16 and a metal sound window (here it is a short and thick single-bend vertical tube sub-sound window, which is composed of a thick tube threaded sound window base 32 and a short and thick single-bend tube fitting 33) and other components. Among them, the short and thick single-bend vertical tube sub-sound window of the metal sound window, like the other various types of metal sound windows equipped in the utility model, can be conveniently adjusted, transformed and installed with each other. The above components are also all made of the same metal material such as stainless steel, copper, or silver.

[0156] In the figure, the base of the piano rod cover 1 is according to Fig. 9 , Fig.10 , Fig.11 and Fig.12 The position shown in the weld 4 of the piano rod sleeve base is directly connected to the hexagonal through-hole piano tube 31 for welding and installation; the metal piano tube rear port connection sleeve 34 is connected according to Fig.12The part shown is directly connected and welded to the rear end of the hexagonal through-hole sound box 31. In addition, other combined installations, including the skin of the sound box 9, the welding installation of the inner column 14 and the outer column 16 of the sound box, the installation of the sound window, and the connection and fixing installation with the erhu bar, are all exactly the same as the combined connection installation when the circular through-hole frame sound box 8 is selected in the present invention. Therefore, if the hexagonal through-hole sound box 31 embodiment is selected, the inner cavity of the metal sound box has no sound bar, the inner cavity wall of the sound box has no connection and installation holes and installation gaps, the metal wall surface of the inner cavity of the sound box is smooth and complete without any defects, the volume of the air column in the inner cavity of the sound box is the most complete and maximized, the oscillation and conduction of the resonance harmonics of the sound in the sound box resonance box are particularly sufficient and smooth, and the metal sound window at the rear end of the metal sound box and other types of functional metal sound windows equipped in the present invention can realize the convenient connection and installation of adjustment and transformation with each other, etc., which are all exactly the same as the embodiment of the through-hole frame sound box 8.

[0157] 5. The sound window located at the rear end of the metal sound box of the utility model is changed from the traditional permanently fixed installation structure to a convenient installation structure that can be adjusted and transformed between multiple sound windows with independent functions by humans. After the metal sound windows with independent functions are matched and combined with the metal sound box and installed tightly connected, the metal sound windows have their own unique oscillation characteristics and conduction paths for the resonance harmonics of the sound in the metal sound box cavity. The metal sound windows of the utility model that can adjust and transform multiple sound windows are composed of the following three types of metal sound windows: tube sound windows, flat cover sound windows, and flat cover tube sound windows. The three types of metal sound windows are all made of the same metal materials as the metal sound box. The following are the specific implementation methods of the three types of metal sound windows: tube sound windows, flat cover sound windows, and flat cover tube sound windows:

[0158] (1) Tube Sound Window

[0159] The pipe sound window is composed of two parts: the sound window base and the pipe accessories:

[0160] 1. Sound window base

[0161] like Fig.31 and Fig.32 As shown (can also refer to Figure 1 , Figure 3 and Figure 4 and Fig. 9 , Fig.11 and Fig.12 ), the area between the front and rear ends of the sound window base is in a conical arc tube shape, and the front and rear ends are cylindrical tubes with significantly different thicknesses. When the front end of the sound window base is connected and installed with the rear end of the full metal sound box, there are two connection installation methods: threaded and press-fit. That is, when connected with a metal sound box with an external thread 18 at the rear end of the metal sound box, Fig.31 As shown, a thin tube threaded sound window base 20 with an internal thread 19 of a sound window connection port is selected, or as Fig.51 As shown, a thick tube threaded sound window base 32 with an internal thread 19 of the sound window connection port is selected and combined with its threaded combination for connection and installation; and when connected to the straight cylindrical rear end of the metal piano tube, as shown Fig.32 As shown, a thin tube without an inner thread 19 of the sound window connection port is selected to press the sound window base 24, or as Fig.54 As shown, a thick tube pressure dubbing window base 35 is selected and connected with the pressure-fit combination. Among them, no matter whether the pressure dubbing window base is a thin tube or a thick tube, the tubular inner diameter size of the front end is slightly larger than the outer diameter size of the straight cylindrical rear end of the metal sound box, that is, when the front end of the pressure dubbing window base is completely wrapped and pressed into the straight cylindrical rear end of the metal sound box, and the pressure-fit combination connection and installation are implemented, the overall contact parts of the two must all be in a compressed and sealed state.

[0162] At the same time, when the rear end of the sound window base is connected to the pipe fittings, for pipe fittings with only two specifications of thin pipe and thick pipe, all use the press-fit connection installation combination method. That is, when the rear end of the sound window base is connected to the pipe fittings with a thin pipe diameter, the following is selected: Fig.31 The thin tube thread sound window base 20 shown or as Fig.32 The thin tube pressure dubbing window base 24 shown is installed with its press-fit connection combination; and when the rear end of the sound window base is connected to the pipe fitting of the thick tubular body, then, it is necessary to select Fig.51 The thick tube threaded sound window base 32 shown or as Fig.54 The thick tube dubbing window base 35 shown is installed in combination with the press-fit connection.

[0163] In summary, there are 4 types of sound window bases:

[0164] 1) A thin tube threaded sound window base 20, such as Fig.31 shown.

[0165] 2) A capillary pressure dubbing window base 24, such as Fig.32 shown.

[0166] 3) Thick tube threaded sound window base 32, such as Fig.51 shown.

[0167] 4) Thick tube pressure dubbing window base 35, such as Fig.54 shown.

[0168] 2. Pipe fittings

[0169] The pipe fittings are all composed of a through-hole cylindrical metal pipe, or a through-hole cylindrical metal pipe and several through-hole metal pipe elbows of the same diameter. When the pipe fittings are connected and installed with the rear ends of the four types of sound window bases, the inner diameter of the pipe fittings is slightly larger than the outer diameter of the circular tubular body at the rear end of the sound window base of the same thickness level, that is, the connection and installation method of the pipe fittings and the sound window base is a press-fit tight connection combination installation method. According to the different lengths, thicknesses, horizontal and vertical directions of the cylindrical metal pipes and the number of metal elbows connected with them, there are a total of 3 types of pipe fittings:

[0170] 1) Straight pipe fittings: They are all composed of a single section of through-hole metal straight pipe. There are 4 types of straight pipe fittings:

[0171] (1) Short and thin straight pipe fittings are composed of a short and thin straight pipe.

[0172] (2) Long and thin straight pipe fittings are composed solely of a long and thin straight pipe.

[0173] (3) Short and thick straight pipe fittings are composed of a short and thick straight pipe.

[0174] (4) Long and thick straight pipe fittings, which are composed of a long and thick straight pipe, such as Fig.55 and Fig.56 The long thick straight pipe fitting 37 is shown. Fig.55 It is a front view of a long thick straight tube sub-sound window formed by matching, connecting, installing and assembling a long thick straight tube fitting 37 and a thick tube pressure dubbing window base 35. Fig.56 yes Fig.55 Left view of .

[0175] 2) Single elbow fittings: They are composed of a through-hole metal straight pipe and a through-hole metal pipe elbow with the same diameter as the pipe, which are connected and installed together. The two ends of the combined single elbow fittings can be press-fitted and connected with the rear end of the sound window base. There are 4 types of single elbow fittings:

[0176] (1) Short and thin single elbow pipe fittings are composed of a short and thin straight pipe and a metal pipe elbow with the same diameter as the straight pipe, which are connected and installed together. Fig.41 and Fig.42 The short thin single elbow fitting 29 shown, Fig.41 This is the front view of a short, thin single elbow fitting. Fig.42 yes Fig.41 Left view of .

[0177] (2) Long and thin single elbow pipe fittings are composed of a long and thin straight pipe and a metal pipe elbow with the same diameter as the pipe, which are connected and installed together. Fig.45 and Fig.46 The slender single elbow fitting 30 shown, Fig.45 This is the front view of a slender single elbow fitting. Fig.46 yes Fig.45 Left view of .

[0178] (3) Short and thick single elbow pipe fittings are composed of a short and thick straight pipe and a metal pipe elbow with the same diameter as the pipe, which are connected and installed together. Fig.47 , Fig.48 , Fig.49 , Fig.50 and Fig.51 (See also Fig. 9 , Fig.10 , Fig.11 and Fig.12 ) shown in the figure a short and thick single curved pipe fitting 33 (the sound window outlet 22 of the pipe is a special case of an oblique mouth shape).

[0179] (4) Long and thick single elbow pipe fittings are composed of a long and thick straight pipe and a metal pipe elbow with the same diameter as the straight pipe, which are connected and installed together.

[0180] 3) Double-bend vertical pipe fittings: They are composed of three parts with exactly the same pipe diameter, namely two through-hole metal pipe elbows and a through-hole metal straight pipe connected between the two pipe elbows, which are connected and installed together, and one of the pipe elbow ends is directly press-fitted and installed with the sound window base. Double-bend vertical pipe fittings are divided into the following four types according to their respective structural characteristics of length, shortness, thickness and thinness:

[0181] (1) Short and thin double-bend vertical pipe fittings are composed of a short and thin metal straight pipe and two metal pipe elbows with the same diameter as the pipe, which are connected and installed together. Fig.35 and Fig.36 (See also Figure 1 , Figure 2 , Figure 3 and Figure 4 as well as Fig.31 and Fig.32 ) shown in the short thin double bend vertical pipe fitting 21, Fig.35 It is a front view of a short and thin double-bend vertical pipe fitting 21, Fig.36 yes Fig.35 Left view of .

[0182] (2) Long and thin double-bend vertical pipe fittings are composed of a long and thin metal straight pipe and two metal pipe elbows with exactly the same diameter connected and installed together, such as Fig.37 and Fig.38 The long and thin double-bend vertical pipe fitting 28 shown, Fig.37 is a front view of a slender double-bend vertical pipe fitting 28, Fig.38 yes Fig.37 Left view of .

[0183] (3) The short and thick double-bend vertical pipe fitting is composed of a short and thick metal straight pipe and two metal pipe elbows with exactly the same diameter connected and installed together.

[0184] (4) Long and thick double-bend vertical pipe fittings are composed of a long and thick metal straight pipe and two metal pipe elbows with the same diameter as the pipe, which are connected and installed together. Fig.52 and Fig.53 The long thick double bent vertical pipe fitting 36 shown, Fig.52 The front view of the long thick double curved vertical pipe sub-sound window is formed by connecting and combining the long thick double curved vertical pipe fitting 36 and the thick pipe pressure dubbing window base 35. Fig.53 yes Fig.52 Left view of .

[0185] In summary, after the sound window base and the pipe accessories are assembled and installed, there are 16 types of pipe sound windows, according to the different lengths, thicknesses, and horizontal, vertical, and curved directions of the pipe accessories. If the press-fit and threaded connection between the pipe sound window and the rear end of the metal sound box, as well as the structural characteristics of the pipe accessories such as short and thin, long and thin, short and thick, and long and thick, are ignored, the pipe sound windows can be comprehensively simplified into the following 4 types (including the subdivisions of the 4 types):

[0186] 1. Straight tube sound window: It is composed of straight tube accessories and sound window base. Fig.55 and Fig.56 The long thick straight tube sub-sound window shown is composed of a long thick straight tube fitting 37 and a thick tube pressure dubbing window base 35 which are matched, connected and installed. Fig.55 This is the front view of the sound window of the long thick straight tube. Fig.56 yes Fig.55 Left view. According to this combination method, after the straight tube accessories of different lengths and thicknesses are connected and installed with the threaded sound window base or the pressed sound window base, the following 4 types of straight tube sub-sound windows can be formed:

[0187] 1) Short and thin straight tube sound window 2) Long and thin straight tube sound window

[0188] 3) Short thick straight tube sound window 4) Long thick straight tube sound window

[0189] 2. Single-bend vertical pipe sub-sound window: It is composed of a single-bend pipe fitting vertically connected to the sound window base. Fig.39 As shown, a short thin single curved vertical tube sub-sound window is formed by vertically connecting and assembling a short thin single curved tube fitting 29 and a thin tube threaded sound window base 20; and as shown Fig.43 As shown, a long and thin single curved vertical tube sub-sound window is formed by vertically connecting and assembling a long and thin single curved tube fitting 30 and a thin tube threaded sound window base 20; Fig.47 , Fig.48 , Fig.49 , Fig.50 and Fig.51 As shown, a short and thick single curved pipe fitting 33 and a thick pipe threaded sound window base 32 are vertically connected and installed to form a short and thick single curved vertical pipe sound window (the sound outlet 22 of the pipe sound window is a special case: an oblique mouth shape), wherein, Fig.47 This is the front view of the short, thick, single-bend vertical pipe sub-sound window. Fig.48 yes Fig.47 Right view of Fig.49 yes Fig.47 The left view of Fig.50 yes Fig.47 A top view of Fig.51 yes Fig.49 According to this combination method, after the single-bend pipe accessories of different lengths and thicknesses are vertically connected and installed with the threaded sound window base or the pressed sound window base, the following 4 types of single-bend vertical pipe sub-sound windows can be formed:

[0190] 1) Short thin single curved vertical tube sound window 2) Long thin single curved vertical tube sound window

[0191] 3) Short and thick single curved vertical tube sound window 4) Long and thick single curved vertical tube sound window

[0192] 3. Single-bend horizontal pipe sound window: It is composed of single-bend pipe accessories horizontally connected to the sound window base. Fig.40 As shown, a short thin single curved tube fitting 29 and a thin tube threaded sound window base 20 are connected and installed horizontally to form a short thin single curved horizontal tube sound window; Fig.44 As shown, a long and thin single curved horizontal pipe sub-sound window is formed by horizontally connecting and installing a long and thin single curved pipe fitting 30 and a thin pipe threaded sound window base 20. According to this combination mode, after the single curved pipe fittings of different lengths, thicknesses and thicknesses are horizontally connected and installed with the threaded sound window base or the pressed sound window base, the following four types of single curved horizontal pipe sub-sound windows can be formed:

[0193] 1) Short thin single curved horizontal tube sound window 2) Long thin single curved horizontal tube sound window

[0194] 3) Short and thick single curved horizontal pipe sound window 4) Long and thick single curved horizontal pipe sound window

[0195] 4. Double-bend vertical pipe sound window: It is composed of double-bend vertical pipe accessories and sound window base. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a short thin double curved vertical tube sub-sound window is formed by connecting and installing a short thin double curved vertical tube fitting 21 and a thin tube threaded sound window base 20; Fig.52 and Fig.53As shown, a long thick double curved vertical pipe sub-sound window is formed by connecting and assembling a long thick double curved vertical pipe fitting 36 and a thick pipe pressure dubbing window base 35, wherein: Fig.52 This is the front view of the long, thick, double-bent vertical pipe sub-sound window. Fig.53 yes Fig.52 In this way, after the double-bend vertical pipe accessories of different lengths and thicknesses are connected and installed with the threaded sound window base or the pressed sound window base, the following 4 types of double-bend vertical pipe sub-sound windows can be formed:

[0196] 1) Short thin double curved vertical tube sound window 2) Long thin double curved vertical tube sound window

[0197] 3) Short thick double curved vertical tube sound window 4) Long thick double curved vertical tube sound window

[0198] (2) Flat soundproof window

[0199] The flat cover sound window, except for its connection with the rear end of the erhu sound box and the hollow carved pattern of the sound window, has basically the same main structure as the traditional erhu sound window. The connection between the flat cover sound window and the rear end of the all-metal sound box of the utility model also has the following two types: press fit and threaded:

[0200] 1. Press and level the sound-covering window. Figure 8 and Fig.34 The connection method implemented by the four-ring treble pressure-balancing sound cover window 23 and the straight-cylindrical rear port of the through-hole frame sound box 8 is a press-fit connection installation.

[0201] 2. Threaded flat cover sound window. Fig.33 The four-ring treble threaded flat cover sound window 25 shown is connected by the internal thread 19 of its sound window connecting port and the external thread 18 of the rear port of the metal sound box 7 with its own sound box skin frame, that is, a threaded connection installation.

[0202] If we ignore the press-fit and threaded connection installation methods between the flat cover sound window and the rear port of the erhu all-metal sound box, the flat cover sound window can be combined and simplified into the following 4 types (each type has two connection installation methods: press-fit and threaded):

[0203] 1. Four-ring treble flat cover sound window:

[0204] like Figure 5 , Figure 7 and Figure 8 As shown, the combination connection installation of the four-ring treble pressure-leveling sound window 23 and the through-hole metal sound box 8 is to directly press the four-ring treble pressure-leveling sound window 23, whose circular tubular inner diameter of the flat sound window is slightly larger than the circular tubular outer diameter of the rear port of the through-hole metal sound box 8, into the straight rear port of the metal sound box to implement a press-fit tight connection combination installation. The single-row front view, left view, and NN cross-sectional view of the four-ring treble pressure-leveling sound window 23 are shown in FIG. Fig.57 , Fig.58 and Fig.59 As shown, Fig.57 The hollow carved pattern at the central circumference of the sound window of the four-ring treble pressure-balancing sound window cover 23 shown in the single-row front view is composed of four annular hollow carved patterns evenly distributed in four groups of similar geometric figures with successively smaller areas. Fig.60 It is a schematic diagram of the engraved hollowing of the sound window of the four-ring treble pressure-balancing cover sound window 23. In the figure, all the blank areas of the geometric figures of the engraved patterns are processed and hollowed out.

[0205] 2. Three-ring treble pressure balancing sound cover window:

[0206] like Fig.61 and Fig.62 As shown, Fig.61 It is a single-row front view of a three-ring treble pressure-balanced sound window 38. The hollow carved pattern on the central circumference of the sound window is composed of three groups of three evenly distributed circular hollow carved patterns with different geometric shapes. Fig.62 It is a schematic diagram of the engraved hollowing of the sound window of the three-ring treble pressure-balancing cover sound window 38. In the figure, all the blank areas of the geometric figures of the engraved patterns are processed and hollowed out.

[0207] 3. Bass flat cover sound window:

[0208] like Fig.63 and Fig.64 As shown, Fig.63 It is a single row front view of the bass flat cover sound window 39, Fig.64 It is a schematic diagram of the sound window engraving and hollowing of the bass flat cover sound window 39. In the figure, all the blank parts of the geometric figures of the engraved patterns are processed and hollowed out.

[0209] 4. Subwoofer flat cover sound window:

[0210] like Fig.65 and Fig.66 As shown, Fig.65 It is a single-row front view of the subwoofer flat cover sound window 40. Fig.66 It is a schematic diagram of the carved and hollowed-out sound window of the subwoofer flat cover sound window 40. In the figure, there are no hollow carved patterns, nor any processed hollowed-out and removed parts of the blank parts of the geometric figures, that is, the subwoofer flat cover sound window 40 is a fully enclosed flat cover sound window without any hollow carved patterns.

[0211] (3) Flat cover pipe sound window

[0212] The flat-covered tube sound window is the third type of sound window in the utility model of convertible multi-sound windows, which is made by combining the structural features of the above two types of tube sound windows and flat-covered sound windows. The flat-covered tube sound windows are composed of two parts: a flat-covered tube sound window base and tube accessories. The tube accessories are exactly the same as the various types of tube accessories that make up the aforementioned tube sound windows. The rear end of the flat-covered tube sound window base is exactly the same as the size and specifications of the short cylinder at the rear end of the sound window base of the tube sound window component, and the outer diameter of the short cylinder also has different thicknesses. When the rear end of the flat-covered tube sound window base is combined and connected with the tube accessories, they are all press-fit connection and installation methods, which is exactly the same as the combination and installation method when the rear end of the sound window base of the tube sound window component is connected to the tube accessories. When the front end of the flat-covered tube sound window base is combined and connected with the rear end of the all-metal sound box of the utility model, there are also two combination connection and installation methods: press-fit and threaded. The flat cover pipe sound window base is a fully enclosed structure except for its front and rear ports. Similar to the four types of sound window base components in the aforementioned pipe sound window, the flat cover pipe sound window base also has the following four types:

[0213] 1. The capillary pressure leveling cover tube sound window base 41, such as Fig.67 shown.

[0214] 2. The thick pipe is pressed to level the cover pipe sound window base 42, such as Fig.68 shown.

[0215] 3. Thick tube threaded flat cover tube sound window base 43, such as Fig.69 shown.

[0216] 4. Thin tube threaded flat cover tube sound window base 44, such as Fig.70 shown.

[0217] When the above four types of flat-covered pipe sound window bases are matched, combined, connected and installed with pipe accessories of various structural characteristics such as thickness, length, single bend and double bend, the flat-covered pipe sound window also has various types similar to the pipe sound window, such as the four flat-covered pipe sound windows in the following embodiments:

[0218] 1. Short and thin pressure-balanced cover double-bend vertical pipe sound window. Fig.67 As shown, it corresponds to Fig.57 The NN cross-sectional view of the short and thin pressure-matched cover double-bend vertical tube sound window, in which the short and thin double-bend vertical tube fitting 21 is press-fitted and installed with the thin tube pressure-matched cover tube sound window base 41, that is, it is combined into a short and thin pressure-matched cover double-bend vertical tube sound window.

[0219] 2. Long and thick pressure leveling cover straight pipe sound window. Fig.68 As shown, the long thick straight tube fitting 37 is press-fitted and connected with the thick tube pressure-matched cover tube sound window base 42 to form a long thick pressure-matched cover straight tube sound window.

[0220] 3. Short thick threaded flat cover single curved vertical pipe sound window. Fig.69 As shown, it corresponds to Fig.49 The KK cross-sectional view of the short thick threaded flat cover single curved vertical tube sound window, in which the short thick single curved tube fitting 33 is vertically press-fitted and installed with the thick tube threaded flat cover tube sound window base 43 to form a short thick threaded flat cover single curved vertical tube sound window.

[0221] 4. Short thin thread flat cover single curved horizontal pipe sound window. Fig.70 As shown, the short thin single bend pipe fitting 29 is installed by being horizontally pressed and connected with the thin tube thread flat cover pipe sound window base 44, so as to be combined into a short thin thread flat cover single bend horizontal pipe sound window.

[0222] In summary, the multi-tone window-changeable orchestral erhu all-metal sound box of the utility model mainly has the following three structural features and functional characteristics:

[0223] 1. The two structural forms of the all-metal sound box of the utility model, the sound box, sound skin, sound window and the special parts such as the sound bar cover and the semi-hexagonal frame (Note: the hexagonal through-hole sound box does not need to be equipped with a semi-hexagonal frame) are all made of the same metal material such as stainless steel, copper, or silver. Among them, the sound box and the sound skin can be made of the same piece of metal material to form a single independent component of the overall integrated sound box with the sound skin frame.

[0224] At the same time, the combination of the two special components of the full metal sound box and the semi-hexagonal frame, or the separate setting of the special component of the neck cover in the hexagonal through-hole sound box, makes it possible to completely eradicate the entire vertical upright neck that originally directly and vertically blocks the sound wave vibration center source part of the traditional erhu sound box, which passes through the entire sound box. After the eradication of this section of the neck, the metal wall of the full metal sound box is complete and smooth without any wall defects, the air column volume in the sound box is the most complete and maximized, and the oscillation and conduction of the resonance harmonics of the piano sound generated in the metal sound box resonance box are particularly full and smooth. At the same time, due to the setting of special components such as the neck cover and semi-hexagonal frame, not only the inner cavity of the full metal sound box completely eliminates the entire vertical upright neck that originally existed in the inner cavity of the traditional erhu sound box, but also, for users who are accustomed to using hexagonal or octagonal erhu sound boxes, when operating the round full metal sound box erhu with special combination components such as the neck cover and semi-hexagonal frame, they can still naturally retain all the bow operation skills and operating habits they originally had on the hexagonal or octagonal sound boxes.

[0225] 2. The two structural types of all-metal sound boxes of the present invention change the sound window located at the rear end of the metal sound box from the traditional permanently fixed installation structure to a connection and installation structure in which the user can independently select the metal sound window that matches the emotion or range of the music among the various types of metal sound windows with independent functions of the present invention, and the metal sound window can be conveniently adjusted and transformed with the rear end of the sound box.

[0226] 3. The two structural forms of the all-metal sound box of the utility model have multiple sound windows that can be conveniently adjusted and changed at the rear end and connected and installed. In addition to setting a number of flat-cover sound windows that are basically the same as the main structure of the sound windows of the traditional erhu sound box, all of them are composed of metal pipe sound windows with the main structural modeling characteristics of pipe wind instruments. According to the different lengths, thicknesses, horizontal and vertical directions of the pipe paths, and other characteristics, 16 kinds of pipe accessories can be formed. The 16 kinds of pipe accessories correspond to the sound window base or the flat-cover pipe sound window base to form a sound window. There are various types of metal tube sound windows with different structural shapes such as the length, thickness, straightness and curvature of the cylindrical tube body. When the metal tube sound window with a fully enclosed structure is tightly connected and assembled with the rear end of the all-metal sound box, the air column in the inner cavity of the all-metal sound box and the air column in the inner cavity of the metal tube sound window pipe are interconnected and integrated. At the same time, the sound outlet of the fully enclosed metal tube sound window becomes the only air outlet and the only sound outlet shared by the inner cavity of the all-metal sound box and the inner cavity of the metal tube sound window pipe and the outside space. Therefore, when the two structural types of all-metal sound boxes of the utility model are matched, combined, connected and installed with the various types of metal tube sound windows of the utility model, the main structure of the all-metal sound box of the erhu, a stringed instrument, is organically integrated with the metal tube sound window having the main structural characteristics of the tube instrument, and is organically combined into an integrated string and pipe erhu; and when the two structural types of all-metal sound boxes are matched, combined, connected and installed with the various types of flat cover sound windows of the utility model, it can also be used as a traditional erhu, so that the utility model has the dual functional characteristics of being able to be used as an integrated string and pipe erhu and as a traditional erhu.

[0227] Thus, the utility model is produced, which is mainly composed of erhu string instruments and supplemented by wind instruments, and the new structure of string instruments and wind instruments is compatible with each other and durable, with multi-tone windows and transformable orchestral integrated erhu full-metal sound box.

Claims

1. A multi-tone window changeable orchestral erhu full metal sound box, characterized by: Its all-metal sound box includes two structural types: a sound box with a self-attached sound box frame and a sound box with a through hole structure. The sound box with a through hole structure includes two types: a sound box with a through hole frame structure and a sound box with a hexagonal through hole structure. All components of the all-metal sound boxes with the two structural types are made of the same metal material, such as stainless steel, copper or silver. The main structure and functional characteristics of the two structural types of all-metal sound boxes are the same, except for the structure in which the sound box and the sound box are connected and the shape of the sound box. The all-metal sound box with a self-attached sound box frame structure is assembled and installed by a sound box rod sleeve (1), a first half hexagonal frame (5), a sound box with a self-attached sound box frame (7), a sound box support fixing inner column (14), a sound box support fixing outer column (16) and a metal sound window. A sound box rod that does not extend into the sound box with a self-attached sound box frame (7) is inserted into the sound box rod sleeve (1). The sound box rod sleeve (1) is welded and fixed to the first half hexagonal frame (5). The first half hexagonal frame (5) is arranged on the upper part of the sound box with a self-attached sound box frame (7). The sound box with a self-attached sound box frame (7) and the sound box with its own sound box body are single independent components of an integral integrated sound box made of the same piece of metal material. The metal sound window has multiple types, and the user can choose any one of them to connect and install it with the rear end of the sound box in a convenient way. The all-metal sound box of the through-hole frame sound box structure is assembled and installed by a sound box rod sleeve (1), a second semi-hexagonal frame (6), a through-hole frame sound box (8), a sound box skin (9), a semi-hexagonal pressing plate (11), a sound box support fixing inner column (14), a sound box support fixing outer column (16) and a metal sound window. The sound box rod sleeve (1) is inserted with a sound box rod that does not extend into the through-hole frame sound box (8). The sound box rod sleeve (1) is arranged on the second semi-hexagonal frame (6), and the second semi-hexagonal frame (6) is arranged on the upper part of the through-hole frame sound box (8). The sound box skin (9) is fixed to one end of the through-hole frame sound box (8). The semi-hexagonal pressing plate (11) presses the upper part of the sound box skin (9). The sound box support fixing inner column (14) and the sound box support fixing outer column (16) are both arranged at the bottom of the through-hole frame sound box (8). Similarly, the metal sound window has multiple types, and the user can choose any type to connect and install it with the rear end of the sound box in a convenient way. The all-metal sound box of the through-hole frame sound box structure is assembled and installed by a sound box rod sleeve (1), a sound box skin (9), a sound box skin covering (10), a hexagonal through-hole sound box (31), a sound box support fixing inner column (14), a sound box support fixing outer column (16) and a metal sound window. The sound box rod sleeve (1) is inserted with a sound box rod that does not extend into the hexagonal through-hole sound box (31). The sound box rod sleeve (1) is arranged at the top of the hexagonal through-hole sound box (31). The sound box skin covering (10) presses the sound box skin (9) against one end of the hexagonal through-hole sound box (31). The sound box support fixing inner column (14) and the sound box support fixing outer column (16) are both arranged at the bottom of the hexagonal through-hole sound box (31). Similarly, there are multiple types of metal sound windows, and the user can choose any one of them to be conveniently adjusted and connected to the rear end of the sound box.

2. The multi-tone window changeable orchestral erhu full metal sound box according to claim 1 is characterized by: The structural features and functional characteristics of the piano neck sleeve (1), the first semi-hexagonal frame (5) and the second semi-hexagonal frame (6) are completely the same.

3. The multi-tone window changeable orchestral erhu full metal sound box according to claim 1 is characterized by: The metal sound window that can be conveniently transformed and combined with the rear end of the all-metal sound box for connection and installation has three types: tube sound window, flat cover sound window and flat cover tube sound window. Among them, the metal tube sound window composed of the tube sound window and the flat cover tube sound window, the tube fittings of its components are all composed of cylindrical through-hole metal tubes, or cylindrical through-hole metal tubes and a number of through-hole metal tube elbows with the same diameter as the tube, and all have the main structural modeling characteristics of the cylindrical tube body of the wind instrument, and the following tube fittings are respectively included: short thin straight tube fittings, long thin straight tube fittings, short thick straight tube fittings, long thick straight tube fittings (37) , short and thin single-bend pipe accessories (29), long and thin single-bend pipe accessories (30), short and thick single-bend pipe accessories (33), long and thick single-bend pipe accessories, short and thin double-bend vertical pipe accessories (21), long and thin double-bend vertical pipe accessories (28), short and thick double-bend vertical pipe accessories, long and thick double-bend vertical pipe accessories (36). According to the different lengths and thicknesses of the pipe accessories and the horizontal, vertical and curved characteristics of the pipeline path, the pipe accessories correspond to various types of metal pipe sound windows with different lengths, thicknesses and curved structures of the cylindrical pipe body, so that users can choose and install them according to the emotion or range of the musical instrument.

4. The multi-tone window changeable orchestral erhu full metal sound box according to claim 3 is characterized by: Except for the connection method between the flat cover sound window and the rear end of the erhu sound tube and the hollow carved pattern of the sound window, the four-ring treble pressure-balancing sound window (23), the four-ring treble thread-locked flat cover sound window (25), the three-ring treble pressure-balancing sound window (38), the bass flat cover sound window (39) and the sub-bass flat cover sound window (40) of the flat cover sound window are the same as the main structure of the traditional erhu sound window. When the all-metal sound tubes of the two structural methods are matched, combined, connected and installed with the flat cover sound windows, they can both be used as traditional erhu.

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