Muting device of action machine with journal sticking structure

Abstract

The invention relates to the field of musical instruments, and provides a muting device of a journal sticking structure string striking machine, the string striking machine comprises a hammer head handle and a sound making head screw rod, the muting device comprises a plurality of rotating shaft supports and rotating shafts, the rotating shaft supports are provided with rotating shaft support through holes, a baffle plate profile is arranged between every two adjacent rotating shaft supports, and the baffle plate profile is of a bending structure. A round through groove is formed in the bent position of the baffle profile, an irregular dovetail-shaped clamping groove is formed in the side, close to the hammer head handle, of the upper portion of the baffle profile, a photoelectric scanning circuit board and a thin film flat cable are arranged in the groove, a mute wool mat is arranged on the same side close to the lower portion of the irregular dovetail-shaped clamping groove, and a sound making wool mat is arranged on the side, close to the sound making head lead screw, of the lower portion of the baffle profile. The rotating shaft penetrates through all the through holes and the circular through groove, one end of the rotating shaft is sleeved with a rotating arm, and the rotating shaft is tightly matched with the circular through groove. The section bar and the optical axis are integrated, the included angle between the baffle section bars can be adjusted to adapt to dislocation between planes where different string array groups are located, the scanning circuit board is installed on the upper portion of the section bar, and installation, maintenance and thin film flat cable disassembly and assembly are facilitated.

Description

Technical Field

[0001] The invention relates to the field of musical instruments, and in particular to a silencing device for a string action with an axis-holding structure. Background Art

[0002] In the current piano mute system, an aluminum profile baffle with a cross-section similar to the lowercase letter b is commonly used. The baffle is combined with the shaft to form an integrated cam rotating device. The lower part of this device is designed as a rotatable cylindrical long shaft, and the upper protruding baffle (equipped with a buffer pad) is used to block the hammer handle of the piano action, thereby effectively preventing the hammer from hitting the strings to produce sound. This device is widely used because of its low aluminum profile material cost, simple processing and convenient installation.

[0003] However, the integrated cam rotating device also has significant defects: because the strings of the bass area of ​​the piano are wound with thick copper wire to reduce the frequency, the strings of the thinner steel wires in the middle and treble areas are not in the same plane, which requires that the position of the protrusion that blocks the hammer handle must be adjustable. However, the protrusion of the b-shaped cross-section aluminum profile is fixed and cannot be adjusted, so it can only compromise to meet the blocking function, which will lead to the inappropriate position of the protrusion, blocking the hammer handle too early, thereby shortening the hammer stroke, affecting the key depth and playing feel. In addition, the diameter of the cylindrical part of the aluminum profile baffle is about 6 mm. Although it can replace the same size stop on the hammer, for the hammer that is about 1.3 meters long and traversed by 3 to 4 brackets, the rigidity of its cylindrical long axis is insufficient, the hammer handle is easy to vibrate and produce noise when struck, and the poor coaxiality leads to a large rotation torque. If installed improperly, there is also a risk that the long axis will slip out of the gap of the C-shaped bracket. At the same time, the design of the B-shaped cross-section of the aluminum profile also limits the choice of brackets, and only C-shaped brackets can be used instead of O-shaped brackets.

[0004] Utility model patent 202320769826.9 discloses a technology that combines an infrared photoelectric scanning circuit board with a silent baffle. Although this technology has the advantage of quick installation, it is found in practice that there are still some shortcomings. When replacing the infrared photoelectric scanning circuit board, the action must be removed from the piano, and the silent baffle must be removed from the action. Only then can the infrared photoelectric scanning circuit board and the FPC film cable connected to it be inserted or removed from the dovetail slot of the silent baffle. This method of removing the action and the silent baffle is cumbersome and time-consuming, and the extra-long FPC film cable needs to be specially customized and is costly. Summary of the invention

[0005] In order to help solve the above technical problems, the present invention provides a silent device for a hammer action with an axis-holding structure, which adopts the following technical solutions: A silencing device for a string action with an axis-holding structure, the string action comprising a hammer handle and a mute head screw, wherein the silencing device comprises: A plurality of rotating shaft brackets are provided with rotating shaft bracket through holes, a baffle profile is arranged between two adjacent rotating shaft brackets, the baffle profile is a bent structure, a circular through groove is arranged at the bending part of the baffle profile, an irregular dovetail-shaped slot is arranged on the upper side of the baffle profile close to the hammer handle, the top end is a non-circular right angle, a step is also arranged at each of the two corners of the bottom of the irregular dovetail-shaped slot, an infrared photoelectric scanning circuit board and a thin film wiring are arranged in the slot, a mute pad is also arranged on the side of the circular through groove below the irregular dovetail-shaped slot on the baffle profile, a mute pad is arranged on the side of the lower part of the baffle profile close to the mute head screw rod; the rotating shaft passes through all the through holes and the circular through groove, a rotating arm is sleeved on one end of the rotating shaft, and the rotating shaft is fastened to the circular through groove by screws or colloids.

[0006] Preferably, the cross-section of the circular through groove opened at the bending part of the baffle profile is set to be Ω-shaped, and the notch is provided with a row of threaded holes, and the screws are passed through the threaded holes to clamp the notch and fasten the rotating shaft.

[0007] Preferably, the pivot arm is provided with a pivot arm through hole, one end of the pivot shaft is inserted into the pivot arm circular hole and fixed to the pivot arm by a locking screw, and a first L-shaped positioning hook is connected to the side of the pivot arm away from the pivot bracket.

[0008] Preferably, the mute device further comprises a limiting ring, the other end of the rotating shaft is inserted into the central circular hole of the limiting ring, a limiting rod parallel to the rotating shaft is provided on the limiting ring, and the limiting rod is closely attached to the upper side of the rotating shaft bracket close to the limiting ring.

[0009] Preferably, a buffer ring of the bushing shaft is provided on the inner side of the swing arm, and a torsion spring is surrounded by the outer periphery of the buffer ring. The torsion spring is close to the pin bushing plastic sheath on one side of the swing arm and is stuck in the hook groove formed by the swing arm and the first L-shaped positioning hook.

[0010] Preferably, a second L-shaped positioning hook is provided at the bottom of the shaft bracket near the rotating arm, and the pin bushing plastic sheath of the torsion spring near one side of the shaft bracket is inserted into the hook groove formed by the shaft bracket and the second L-shaped positioning hook.

[0011] Preferably, an L-shaped bracket with ears is provided at the rear end of the upper part of the rotating arm, and metal baffles are bent and drooped on both sides of the lower part of the main body and straddle the rotating arm. The film cable adapter plate is fixed to the threaded holes on the upper part of the L-shaped bracket with ears by screws, and the film cable adapter plate is welded with an FFC film cable socket on the plate surface facing the front end of the rotating arm.

[0012] Preferably, a 0.5mm thin film wiring socket is provided at one end of the infrared photoelectric scanning circuit board, which is on the same surface as all the photoelectric sensors welded on the board, and the head protrudes beyond the irregular dovetail-shaped slot on the upper part of the baffle profile.

[0013] In summary, the present invention has a novel design and a simple device structure. It utilizes the profile and the rotating shaft to form an integral whole, which can not only adjust the angle between the baffle profiles of each section to adapt to the misalignment between the planes where different string arrays are located, but also allows an O-shaped bracket to replace the C-shaped bracket to prevent the rotating shaft from escaping from the bracket gap. The rigidity of the structure is also strengthened, and the infrared photoelectric scanning circuit board can be conveniently replaced directly on the piano without disassembling the hammer and the silent baffle. Conventional FFC film wiring is used instead of special FPC film wiring, which reduces costs, has strong practicality, and is suitable for installation on upright pianos. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a front view of an embodiment of a silent device for a string machine with an axis-holding structure according to the present application; Figure 2 for Figure 1 a right side view of the illustrated embodiment; Figure 3 for Figure 1 a left side view of the illustrated embodiment; Figure 4 for Figure 1 A schematic cross-sectional view of the baffle profile and its sound-damping felt pad and mute felt pad in the illustrated embodiment; Figure 5 A schematic cross-sectional view of a baffle profile and a sound-damping felt pad and a mute felt pad according to another embodiment of the present application; Figure 6 A top view of the rotating arm and its L-shaped positioning hook of the present application; Figure 7 This is a cross-sectional schematic diagram of the L-shaped positioning hook of the present application; Figure 8 A side view of the shaft support and the buffer pad thereof of the present application; Fig. 9 A cross-sectional schematic diagram of a limiting ring and a limiting rod thereof of the present application; Fig.10 It is a schematic diagram of the central section of the L-shaped bracket with ears of the present invention; Fig.11 This is a schematic diagram of the present application installed on an upright piano action.

[0015] Reference numerals: 1-rotating shaft; 2-limiting ring; 3-limiting rod; 4-fixing screw; 5-rotating shaft bracket; 6-silent felt pad; 7-baffle profile; 8.1-first L-shaped positioning hook; 8.2-second L-shaped positioning hook; 9-torsion spring; 10-plastic bushing; 11-rotating arm; 12-locking screw; 13-silent felt pad; 14-buffer felt pad; 15.1-0. 5mm film cable socket; 15.2-main control board cable socket; 16-film cable; 17-infrared photoelectric scanning circuit board; 18-film cable adapter board; 19-L-shaped bracket with ears; 20-photoelectric sensor; 21-reflection block; 22-hammer; 23-string; 24-hammer handle; 25-mute head screw; 26-wire rope end; 27-acting mechanism bracket; 28-hammer back stop; 29-wire rope; 30-mute control box. DETAILED DESCRIPTION

[0016] The present application is further described below in conjunction with the accompanying drawings, and the structure and principle of the present application are very clear to people in the field. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0017] Figure 1 The front view of an embodiment of a silencing device for a string action with a shaft-holding structure of the present application. The string action includes a hammer handle 24 and a mute screw 25. The mute device may include a plurality of shaft brackets 5. The shaft brackets 5 are provided with shaft bracket through holes. A baffle profile 7 is provided between two adjacent shaft brackets 5. The baffle profile 7 is a bent structure. A circular through groove is provided at the bend of the baffle profile 7. An irregular dovetail-shaped slot is provided on the upper side of the baffle profile 7 near the hammer handle 24. The top is an inverted L-shaped right angle. An infrared photoelectric scanning circuit board 17 is provided in the slot. A mute pad 6 is provided on the side near the hammer handle 24 below the irregular dovetail-shaped slot on the upper side of the baffle profile 7. A mute pad 13 is provided on the lower side near the mute screw 25. The shaft 1 passes through all the through holes and the circular through groove. A rotating arm 11 is sleeved on one end of the shaft 1. The shaft 1 is tightly matched with the circular through groove through a colloid.

[0018] In addition, the pivot arm 11 is provided with a pivot through hole, one end of the shaft 5 is inserted into the pivot through hole, and is fixed to the pivot arm 11 by a locking screw 12, and the first L-shaped positioning hook 8.1 is connected to the side of the pivot arm 11 away from the shaft bracket 5. The mute device also includes a limit ring 2, and the other end of the shaft 1 is inserted into the central circular hole of the limit ring 2. The limit ring 2 is provided with a limit rod 3 parallel to the shaft 1, and the limit rod 3 is close to the upper side of the shaft bracket 5 close to the limit ring 3. A buffer ring of the bushing shaft is provided on the inner side of the pivot arm 11, and the outer periphery of the buffer ring surrounds the torsion spring 9. The pin bushing plastic sheath of the torsion spring 9 close to the side of the pivot arm 11 is inserted into the hook groove formed by the pivot arm 11 and the first L-shaped positioning hook 8.1. A second L-shaped positioning hook 8.2 is provided at the bottom of the rotating shaft bracket 5 near the rotating arm 11, and the pin bushing plastic sheath of the torsion spring 9 near the rotating shaft bracket 5 is inserted into the hook groove formed by the rotating shaft bracket 5 and the second L-shaped positioning hook 8.2. The action also includes an action bracket 27, a mute control box 30 and a steel wire 29, the end 26 of the steel wire is connected to the end hook of the rotating arm 11, the action bracket 27 is used to fix the rotating shaft bracket 5, one end of the steel wire 29 is connected to the end hook of the rotating arm 11, and the other end is connected to the wrench of the mute control box 30.

[0019] Specifically, the limiting ring 2 and multiple shaft brackets 5 and multiple baffle profiles 7 in the figure are respectively installed on the shaft 1 together with the torsion spring 9, the plastic bushing 10 and the rotating arm 11; the limiting ring 2 is locked by screws and fixed to one end of the shaft 1; the shaft bracket 5 is set close to the limiting ring 2, usually four shaft brackets 5, which are respectively set at both ends of each baffle profile 7, and the shaft 1 is inserted into the same direction of the circular hole of the shaft bracket 5 for intermittent cooperation, and can rotate smoothly; usually three sections The baffle profiles 7 correspond to the high, medium and low-frequency string groups, respectively, and are spaced apart by a shaft bracket 5. The shaft 1 is inserted into the circular through groove provided in the baffle profile 7 for transition fit and is fixed and combined by anaerobic adhesive; the torsion spring 9 is inserted into the other end of the shaft 1, adjacent to the shaft bracket 5, and a plastic sheath 10 is inserted between the torsion spring 9 and the shaft 1; a rotating arm 11 is provided at the end of the shaft 1 adjacent to the torsion spring 9 and the plastic sheath 10, and is fastened to the shaft 1 by a locking screw 12.

[0020] Figure 2 for Figure 1 A right side view of the embodiment shown, Figure 3 for Figure 1 Left view of the embodiment shown. Both figures indicate that the projections of the baffle profiles 7 and their mute felt pads 6 do not overlap, and there may be an angle between the baffle profiles 7 to accommodate the front-to-back misalignment between the high, medium and low-pitched strings. Due to the transition fit between the shaft 1 and the baffle profiles 7, and the long time required for the anaerobic adhesive to cure from initial solidification to complete solidification, sufficient operating time is left to adjust the angles between the baffle profiles 7 during implementation. The baffle profiles 7 can still rotate around the shaft 1 when appropriate force is applied, and the baffle profiles 7 will not rotate around the shaft 1 when no force is applied.

[0021] Figure 4 for Figure 1 A schematic cross-sectional view of a baffle profile and its sound-damping felt pad 13 and mute felt pad 6. Figure 4 The cross section of the middle baffle profile 7 is shaped like the number 2, and a circular through groove is set inside the arc corner. This embodiment is not an O-shaped closed-loop through groove in order to simplify the profile processing technology and reduce costs. The aluminum profile C-shaped through groove is used to cooperate with the optical axis, and a suitable anaerobic adhesive is selected to utilize its long-term holding characteristics to maintain the long-term stability of the structure. Of course, an O-shaped closed-loop through groove is also feasible, but the mold of the baffle profile 7 is relatively complex and the cost is high.

[0022] Figure 5 The present invention is a cross-sectional schematic diagram of another embodiment of a baffle profile 7 and its sound-damping felt pad 13 and a sound-absorbing felt pad 6, wherein the cross-section of the circular through groove at the bend of the baffle profile 7 is set to be Ω-shaped, and a row of threaded holes are set at the notch. Screws are passed through the threaded holes to clamp the notch and hold the rotating shaft 1 tightly. By loosening the entire row of screws on the baffle profile 7, the inclination angle of the baffle profile 7 and the displacement adjustment on the rotating shaft 1 can be conveniently adjusted.

[0023] Figure 4 and Figure 5 It is also shown that a damper pad 13 is pasted on the outer surface of the through groove at the lower end of the baffle profile 7 on the side close to the piano strings to buffer and limit the rebound of the sound head screw 25 of the string action mechanism; and the reverse side of the damper pad 13, that is, the upper end of the baffle profile 7 on the side close to the piano hammer handle 24 is provided with an irregular dovetail-shaped slot, the top of which is an inverted L-shaped right angle, so that the infrared photoelectric scanning circuit board 17 can be inserted into the slot lying horizontally without being inserted vertically from both ends of the slot; a step is also provided at each corner of the bottom of the irregular dovetail-shaped slot, so that a gap is formed between the infrared photoelectric scanning circuit board 17 arranged in the slot and the baffle profile 7, which is used for the routing of the film wiring 16 and isolates the contact short circuit between the bottom surface of the infrared photoelectric scanning circuit board 17 and the metal baffle profile 7; a mute pad 6 is pasted on the baffle profile 7, close to the bottom of the irregular dovetail-shaped slot, on the same side, to buffer and block the hammer handle 24 of the string action mechanism, reduce the impact noise, and prevent the hammer 22 from hitting the string 23, see Figure 1 to Figure 3 .

[0024] Figure 6 This is a top view of the rotating arm and its L-shaped positioning hook of the present application. Figure 1 , Figure 2 , Figure 3 and Fig.11Schematic diagram, one end of the rotating arm 11 is provided with an open through hole perpendicular to its main body, and the rotating shaft 1 is inserted into the opening to cooperate with each other, and the locking screw 12 is used to lock the opening so that the rotating shaft 1 and the rotating arm 11 are firmly combined; loosening and tightening the locking screw 12 can make the rotating arm 11 shift left and right on the rotating shaft 1 to adapt to the hook set at the other end of the rotating arm 11 and the traction position of the wire rope 21; the hook facilitates the connection or separation of the wire rope end 26 and the rotating arm 11 when the string machine is installed or disassembled; a step is processed on the upper part of the rotating arm 11 near the hook to set a first L-shaped positioning hook 8.1, which is tightened by a screw and relies on the step L-shaped right-angle hook to connect to the pin of a bushing plastic sheath of the adjacent torsion spring 9, and the function of the bushing plastic sheath is to prevent noise caused by vibration between metals.

[0025] Figure 7 The cross-sectional diagram of the L-shaped positioning hook of the present application. The first L-shaped positioning hook 8.1 is used to hook the pin of the plastic sheath of the torsion spring 9 bushing. The L-shaped positioning hook is provided with multiple through holes. By selecting through holes in different positions, the appropriate position can be adjusted by telescopic means. In addition to the first L-shaped positioning hook 8.1 provided on the rotating arm 11, the present invention also provides a second L-shaped positioning hook 8.2 on the rotating shaft bracket 5 at one end of the rotating shaft 1 with a screw, as shown in FIG. Figure 1 , Figure 2 and Figure 3 , used to hook the pin of another bushing plastic sheath of the adjacent torsion spring 9.

[0026] Figure 8 The side view of the shaft bracket and its buffer pad of the present application. The shaft bracket 5 is provided with a waisted circular hole for fixing the screw 4 to connect the hammer bracket 27 to adjust the position up and down. The upper part of the shaft bracket 5 is provided with irregular circular holes with a teardrop-shaped cross section in different directions. The buffer pad 14 is laid in the hole. The protrusion facilitates the overlapping connection of the pad to help reduce structural resonance and reduce noise. The setting of the plastic bushing 10 is also to prevent the metal vibration between the shaft 1 and the torsion spring 9 from emitting noise, which has the same function as the plastic sleeve of the two pin bushings of the torsion spring 9. The groove and concave hole set at the bottom of the shaft bracket 5 are convenient for the setting of the second L-shaped positioning hook 8.2 and the nut. It is only used for installing one end of the torsion spring 9 on the shaft 1, and the shaft bracket 5 at other parts of the shaft 1 may not be provided with the groove and concave hole at the bottom.

[0027] Fig. 9The schematic cross-sectional view of the limit ring and the limit rod of the present application. Usually, the wire rope 29 is fixed on the piano housing near the rotating arm 11, giving the rotating shaft 1 a pulling force in the direction of the housing on this side. The limit ring 2 is locked on the rotating shaft 1 by screws. Due to the obstruction of the rotating shaft bracket 5, the rotating shaft 1 is restricted from being pulled by the wire rope 29 and moving, so that the structure remains stable. On the contrary, if the wire rope 29 is fixed on the inner side of the rotating arm 11 due to the structure of the piano housing, in order to prevent the rotating shaft 1 from being pulled by the wire rope 29 in the direction of the housing on the other side, it is only necessary to unscrew the limit rod 3 on the limit ring 2, which is a screw, and screw it back into the original threaded hole from the other side, and move the limit ring 2 to the inner side of the rotating shaft bracket 5 and lock it on the rotating shaft 1. The limiting rod 3 is provided to prevent the shaft 1 together with the baffle profile 7 from rotating disorderly and significantly when installing and disassembling the structural device of the present invention, thereby preventing damage to the action and inconvenience in installation; since the action bracket 27 and the shaft bracket 5 block the limiting rod 3 rotating with the limiting ring 2, its rotation range is limited. Figure 1 In the figure, the limit ring 2 is arranged at the left end of the rotating shaft 1, and the rotating arm 11 and the torsion spring 9 and the plastic bushing 10 are arranged at the right end of the rotating shaft 1. If the wire rope 29 for controlling the switching between mute and string sound needs to be arranged on the other side of the piano, the limit ring 2 is changed to the right end of the rotating shaft 1, and the rotating arm 11, the torsion spring 9 and the plastic bushing 10 are changed to the left end of the rotating shaft 1 in sequence. The torsion spring 9 must be replaced with a reversely wound spiral, and the two L-shaped positioning hooks also need to loosen the screws and change the direction of installation.

[0028] Fig.10 The L-shaped bracket with ears 19 is fastened to the rear end of the upper part of the rotating arm 11 by the locking screw 12. The contact part between the main body of the metal L-shaped bracket with ears 19 and the upper part of the rotating arm 11 is bent with drooping metal baffles on both sides. The metal baffles prevent the L-shaped bracket with ears 19 straddling the rotating arm 11 from rotating, so that the film cable adapter plate 18 fixed to the threaded hole on the upper part of the L-shaped bracket with ears 19 by screws is parallel to the rotating shaft 1 and perpendicular to the side panel of the piano shell. The film cable adapter plate 18 facing the plate surface of the front end of the rotating arm 11 is welded with a film cable socket 15.2 for connecting the sound source main control board and a film cable socket 15.1 for connecting the infrared photoelectric scanning circuit board 17, so as to facilitate the connection of the film cable 16 in the irregular dovetail groove on the upper part of the baffle profile 7 on the rotating shaft 1. This setting improves the method in utility model patent 202320769826.9 in which the cable adapter plate is perpendicular to the shaft and baffle profile, which requires the film cable to be bent for connection, which not only affects the stability of the connection, but also makes it inconvenient to plug and unplug the film cable, and is not conducive to the wiring of the cable adapter plate along the side panels of the piano shell to connect to the main control board fixed on the piano shell.

[0029] Fig.11The present invention is a schematic diagram of the application installed on the action of an upright piano. The mute device of the present invention is fastened by a fixing screw 4 in a common mute fixing threaded hole on an action bracket 27, and crosses the left and right ends of the piano action. In the figure, the mute control box 30 and the wire rope 29 are arranged on the right side of the piano, and the end 26 of the wire rope is connected to the end hook of the rotating arm 11 on the right side of the piano. When the wrench of the mute control box 30 is tightened, the wire rope 29 is pulled, driving the end of the rotating arm 11 to rotate downward, and then the rotating shaft 1 rotates, the baffle profile 7 and its mute felt pad 6 tilt forward, blocking the hammer handle 24 of the action, so that the hammer 22 cannot hit the string 23, and the mute is achieved. During implementation, the steel wire rope 29 can also be pulled by stepping on the piano pedal, driving the rotating arm 11 and the rotating shaft 1 to rotate, so that the baffle profile 7 and its mute felt pad 6 tilt forward, and the hammer handle 23 is blocked, and the piano is mute.

[0030] Combination Figure 1 and Fig.11 , indicating that one end of the infrared photoelectric scanning circuit board 17 disposed in the irregular dovetail slot on the upper part of each baffle profile 7 is provided with a 0.5mm thin film wiring socket 15.1 on the same surface as all the photoelectric sensors 20 welded on the board, and this end protrudes out of the irregular dovetail slot on the upper part of the baffle profile 7. Usually, the hammer handles 24 of each group of hammers 22 of the piano action are spaced several centimeters apart, and a hammer support 27 supporting the action structure is generally provided therebetween. The hammer support 27 and the adjacent hammer handles 24 on both sides are usually much larger than 1 centimeter, so the distance between each baffle profile 7 that blocks the hammer handles 24 of each group of the action and the adjacent hammer support 27 is generally larger than 1 centimeter, which is enough to accommodate the end of the infrared photoelectric scanning circuit board 17 welded with the 0.5mm thin film wiring socket 15.1 that protrudes less than 1 centimeter from the baffle profile 7, that is, the end of the infrared photoelectric scanning circuit board 17 that protrudes from the baffle profile 7 will not touch or conflict with the hammer support 27. The flexible film cable 16 connected to the 0.5mm film cable socket 15.1 at the end of the infrared photoelectric scanning circuit board 17 may touch the hammer frame 27. To prevent scratches or noise, a buffer felt can be pasted at the touching point. The film cable 16 connected to the infrared photoelectric scanning circuit board 17 close to the film cable adapter board 18 is directly inserted into the 0.5mm film cable socket 15.1 on the film cable adapter board 18, while the film cable 16 connected to other infrared photoelectric scanning circuit boards 17 passes through the gap on the back of the infrared photoelectric scanning circuit board 17 in the irregular dovetail slot on the upper part of the other baffle profile 7, and is connected to the film cable socket 15.1 on the film cable adapter board 18, and then connected to the main control board via the cable connected to the main control board cable socket 15.2 on the film cable adapter board 18.

[0031] The thin film cable adapter plate 18 is provided to facilitate the installation and disassembly of the entire hammer. When installing the hammer equipped with the infrared photoelectric scanning circuit board 17 and the thin film cable 16 on the piano, it is only necessary to connect the cable led out of the main control board to the main control board cable socket 15.2 on the thin film cable adapter plate 18. When disassembling, it is only necessary to disconnect the cable led out of the main control board from the main control board cable socket 15.2 on the thin film cable adapter plate 18.

[0032] Since the infrared photoelectric scanning circuit board 17 is arranged on the upper part of the baffle profile 7, it avoids the obstruction of the piano hammer back 28, and the infrared photoelectric scanning circuit board 17 can be directly installed manually, and it is inserted into the irregular dovetail slot on the upper part of the baffle profile 7 in a horizontal position, and glue is applied to the gap between the upper edge of the infrared photoelectric scanning circuit board 17 and the upper edge of the irregular dovetail slot on the upper part of the baffle profile 7 to fix the infrared photoelectric scanning circuit board 17, and the film cable 16 is inserted into the film cable socket 15.1 at the end of the infrared photoelectric scanning circuit board 17 protruding from the baffle profile 7 and locked. When removing the infrared photoelectric scanning circuit board 17, first manually open the lock of the film cable socket 15.1, unplug the film cable 16, and insert a blade into the gap between the upper edge of the infrared photoelectric scanning circuit board 17 and the upper edge of the irregular dovetail slot on the upper part of the baffle profile 7, cut off the fixed glue, and then the infrared photoelectric scanning circuit board 17 lying horizontally in the irregular dovetail slot on the upper part of the baffle profile 7 can be taken out. The above operation does not require the action to be removed from the piano, which is convenient for maintenance, flexible and time-saving. Of course, this technology of placing the infrared photoelectric scanning circuit board and the mute felt pad together on the mute baffle (or rod) and plugging and unplugging the thin film wiring can also be applied to other piano action mute baffles (or rods) with non-shaft-holding structures. The use of multi-layer printed circuit boards can further narrow the infrared photoelectric scanning circuit board.

[0033] The present invention also forms a piano mute device through the baffle profiles 7, the rotating arm 11 and the limit ring 2 that surround the rotating shaft 1, so that the angles of the baffle profiles 7 can be adjusted during the installation process, so that all the hammers 22 of the entire hammer mechanism can approach the strings 23 more evenly, so as to approach the stroke of the string sound state, thereby reducing the influence of the mute state on the playing feel.

Claims

1. A silencing device for a string action with an axis-holding structure, the string action comprising a hammer handle and a mute head screw, characterized in that: The mute device comprises: A plurality of rotating shaft brackets are provided with rotating shaft bracket through holes, a baffle profile is arranged between two adjacent rotating shaft brackets, the baffle profile is a bent structure, a circular through groove is arranged at the bending part of the baffle profile, an irregular dovetail-shaped slot is arranged on the upper side of the baffle profile close to the hammer handle, the top is an inverted L-shaped right angle, a step is arranged at each of the two corners of the bottom of the irregular dovetail-shaped slot, an infrared photoelectric scanning circuit board and a thin film wiring are arranged in the slot, a mute pad is arranged on the side of the circular through groove below the irregular dovetail-shaped slot on the baffle profile, a mute pad is arranged on the side of the lower part of the baffle profile close to the mute head screw rod; the rotating shaft passes through all the through holes and the circular through groove, a rotating arm is sleeved on one end of the rotating shaft, and the rotating shaft is fastened to the circular through groove by screws or colloids.

2. The mute device according to claim 1, characterized in that: The cross section of the circular through groove opened at the bending part of the baffle profile is set to be Ω-shaped, and the notch is provided with threaded holes, and screws are passed through the threaded holes to clamp the notch and tighten the rotating shaft.

3. The mute device according to claim 1, characterized in that: The pivot arm is provided with a pivot through hole, one end of the pivot shaft is inserted into the pivot through hole and fixed to the pivot arm by a locking screw, and a first L-shaped positioning hook is connected to the side of the pivot arm away from the pivot bracket.

4. The mute device according to claim 3, characterized in that: The mute device also includes a limiting ring, the other end of the rotating shaft is inserted into the central circular hole of the limiting ring, and a limiting rod parallel to the rotating shaft is provided on the limiting ring, and the limiting rod is close to the upper side of the rotating shaft bracket close to the limiting ring.

5. The mute device according to claim 3, characterized in that: A buffer ring of the bushing shaft is arranged inside the rotating arm, and a torsion spring surrounds the outer periphery of the buffer ring. The torsion spring is close to the pin bushing plastic sheath on one side of the rotating arm and is stuck in a hook groove formed by the rotating arm and the first L-shaped positioning hook.

6. The mute device according to claim 5, characterized in that: A second L-shaped positioning hook is arranged at the bottom of the shaft bracket close to the rotating arm, and the pin bushing plastic sheath of the torsion spring close to one side of the shaft bracket is inserted into the hook groove formed by the shaft bracket and the second L-shaped positioning hook.

7. The mute device according to claim 3, characterized in that: An L-shaped bracket with ears is provided at the rear end of the upper part of the rotating arm, and metal baffles are bent and drooped on both sides of the lower part of the main body and straddle the rotating arm. The film cable adapter plate is fixed to the threaded holes on the upper part of the L-shaped bracket with ears by screws, and the FFC film cable adapter plate is welded to the plate surface facing the front end of the rotating arm.

8. The mute device according to claim 1, characterized in that: A 0.5mm thin film wiring socket is arranged at one end of the infrared photoelectric scanning circuit board, which is on the same surface as all the photoelectric sensors welded on the board, and the head protrudes beyond the irregular dovetail-shaped slot on the upper part of the baffle profile.

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