KR20010098436A - Keyboard instrument - Google Patents

Abstract

A keyboard instrument, such as an upright piano, basically consists of a keyboard 2, an action 4, a pole assembly 8, a back hollow assembly 12 and an upper door assembly 14. The pawl assembly here has a pawl cover 20, 18, 24 covering the keyboard and an upper door assembly 14 having an open top door 38 connected to the pawl assembly via the back hollow assembly. . The upper door rotates according to the operation of the pole cover of the pawl assembly, which is closed or opened, and when the pawl cover is opened, the top door is opened to form a small gap 52 near the bottom thereof. The small gap 52 causes piano notes to leak out of the casing, increasing the intensity of the piano notes, and sharpening the piano tones. The keyboard musical instrument further includes damping mechanisms 112, 120, and 213 for distributing the resistive load to the closed or open pole cover. That is, the damping mechanism uses rotating dampers 120 and 213 that include viscous fluids 122 and 213z that flow to generate torque that automatically distributes the increased load to the closed pole cover.

Description

Keyboard instrument

The present invention relates to a keyboard instrument such as an upright piano having a structure in which the intensity of sound is increased.

In general, the upright piano is configured to realize the opening function of the top cover hinged to the upper side of the case so that the user or the player can open the top cover to increase the volume of the piano sound. However, since a general user tends to place an object or an object on the top cover, an upright piano may not always show an opening function for increasing the volume of the piano sound.

It is an object of the present invention to provide a keyboard instrument such as an upright piano which realizes an opening function for increasing the volume of the piano without being blocked by an object or object placed on the top cover.

Keyboard instruments, such as upright pianos, are basically composed of a keyboard, action, case assembly, fall assembly, back hollow assembly, and upper door assembly. Here, the pole assembly is provided with a pole cover covering the keyboard, and the upper door assembly is connected to the pole assembly by the back hollow assembly. The upper door pivots in response to the closing or opening operation of the pawl cover of the pawl assembly, and when the pawl cover is opened, the top door opens to form a small gap close to the bottom thereof. The small gap causes the piano sound to partially leak out of the casing, increasing the intensity of the piano sound, and improving the clarity in the timbre of the piano sound. Since the keyboard is provided with the upper door so that a user or a player may not be blocked by an object or an object placed on the top cover, it is possible to ensure the opening function of opening the upper door in relation to the opening of the pole cover. Thus, the keyboard musical instrument can show the effect of improving the strength of the sound.

The keyboard musical instrument further includes a damping mechanism for distributing the resistive load to the closed or open pole cover. That is, the damping mechanism uses a rotary damper that includes a viscous fluid that moves in response to the pivoting movement of the pole cover to generate torque that automatically increases the load applied to the closed pole cover. Therefore, it is possible to prevent an accident which occurs due to the closing of the pole cover of the piano.

1 is a cross-sectional view showing selected components in the configuration of an upright piano with the pawl assembly in a closed position;

Fig. 2 is a sectional view showing a part selected in the configuration of the upright piano in which the pawl assembly is in the open state;

3 is a perspective view showing the appearance of a damping mechanism applicable to an upright piano;

4 is a cross-sectional view showing that the internal structure of the rotary damper of the damping mechanism is closed in relation to the pawl assembly;

Fig. 5 is a cross sectional view showing that the internal structure of the rotary damper of the damping mechanism is opened in relation to the pawl assembly;

Fig. 6 is a perspective view showing partly rupture of selected parts to realize an example of a damping mechanism for a pole assembly;

FIG. 7A is a cross sectional view showing the internal structure of a rotary damper which is a major part of the damping mechanism shown in FIG. 6 when the pawl assembly is in the closed position; FIG.

Fig. 7B is a cross sectional view showing the internal structure of the rotary damper when the pawl assembly is in the intermediate position;

Fig. 7C is a cross sectional view showing the internal structure of the rotary damper when the pawl assembly is in the open position.

<Description of Symbols for Main Parts of Drawings>

2: Keyboard 4: Action

6 case assembly 8 pole assembly

12 Back Hollow Assembly 14 Upper Door Assembly

23: pivot mechanism 36: upper upper door

38: lower upper door 42: strap hinge

46: connecting member 48: tab board

52: gap 112: damping mechanism

These and other objects, features and embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

1 and 2 show a top cross-sectional view of an upright piano according to a preferred embodiment of the present invention. The upper part of the upright piano is provided with a keyboard 2, an action 4 and a case assembly 6, and Figs. 1 and 2 only show selected parts of the upper part of the case assembly 6. The lower part of the case assembly 6 is provided with a string and tuning keys, which are typical components of an upright piano, and will not be described. Similarly, since the keyboard 2 and the action 4 are also typical components of the upright piano, detailed description thereof will be omitted.

The case assembly 6 includes a pawl assembly 8 hinged to side arms 10 located at both ends of the keyboard 2, a back hollow assembly 12 connected to the pawl assembly 8, and the case. An upper door assembly 14 is provided which connects both ends to the side 16 of the assembly 6. The upper door assembly 14 functions like a closed front panel to hide the action 4 inside the case assembly 6.

The case assembly 6 also includes a lower door assembly, a top cover, a base and a rear panel, all of which are not shown in the drawings as a typical part of an upright piano.

The pawl assembly 8 provides an open cover for covering the keyboard 2, comprising a top cover 18 and a front cover 20. The top cover 18 is attached to the pivot mechanism 23 by two thin metal arms (ie, pivot arms) 22. The pivot mechanism 23 is fixed to the side arm 10 located at the side end of the keyboard 2. It is possible to provide a damping mechanism so that the pawl cover is not closed by the user or the player. The damping mechanism can be constructed similarly to that disclosed in European patent application publication EP 0697541 A1. It is also possible to employ a pole mechanism similar to that disclosed in European patent application publication EP 0901117 A2. In addition, the details of the foregoing announcement will be described later.

FIG. 1 shows the pawl assembly 8 closed, while FIG. 2 shows the pawl assembly 8 open. In order to realize the distance or angle of spacing between the closed position and the open position of the pawl assembly 8, the pivot arm 22 undergoes a limited rotation about the pivot mechanism 23, ie a rotation of approximately 130 °. in need.

The back hollow assembly 12 includes a rear cover (or panel) 24 extending across the width of the keyboard 2. The front end of the rear cover 24 is connected to the rear end of the top cover 18 by a strap hinge 28. Two pins 32 are arranged close to the rear end 30 of the rear cover 24 to be in contact with the lower side of the rear cover 24. Specifically, the two pins 32 are respectively provided at the side ends of the rear cover 24, and are coupled to the guide slot 34 elongated along the inner surface of the side arm 10 in an inclined manner. Is placed.

In the closed state of the pawl assembly 8 as shown in FIG. 1, the rear cover 24 is supported horizontally and maintains approximately the same height as the top cover 18, which is the rear cover 24. This is because the front end 26 of is supported by the strap hinge 28, and the rear end 30 thereof is supported by the pin 32. In the closed state, the user or performer gradually opens the pole cover to place the pole assembly 8 in the open state as shown in FIG. According to the operation of the open pole cover, the pin 32 originally located close to the rear end 30 of the rear cover 24 slides to the rear side of the guide slot 34 to be slid. In addition, the front end 26 of the rear cover 24 moves together with the rear end of the upper cover 18 to rotate about the pivot mechanism 23 along a predetermined trajectory. In the open state of the pawl assembly 8 as shown in FIG. 2, the front end 26 of the rear cover 24 moves backwards with a lower height as compared to its original position. Thus, the rear cover 24 is inclined slightly forward.

The upper door assembly 14 includes an upper upper door 36 and a lower upper door 38. Usually, the upper upper door 36 is fixed at the position of the side portion 16 of the case assembly 6 so that an upright piano can be used. An upper end of the lower upper door 38 is connected to a lower end of the upper upper door 36 by a strap hinge 42, and the lower upper door 38 is rearwardly around the strap hinge 42. Since it is possible to rotate, it enters the inside of the case assembly 6 of the upright piano. For example, in order to tune the upright piano, the upper upper door 36 can be removed by a conventional method.

The lower end 44 of the lower upper door 38 is connected to the rear end 30 of the rear cover 24 by a plurality of connecting members 46, and the connecting member 46 is connected to the lower upper part. It is provided in the both ends of the lower end 44 of the door 38. It is also possible to install additional connecting members 46 along the middle of the tab board 48. Each connecting member 46 is very simple in configuration and consists of, for example, only one tab board 48. The tab board 48 is installed to extend in the downward direction from the lower end 44 of the lower upper door 38, each bolt 50 consisting of a shaft and a head is a tap hole of the tab board 48 It is positioned to engage with. Here, the bolt 50 extends rearward from the rear end 30 of the rear cover 24. In the closed state of the pawl assembly 8 as shown in FIG. 1, the bolt 50 and the tab board 48 are fixed so that the lower upper door 38 in the closed state (ie, vertically closed state). It is possible to reliably stop. When the lower upper door 38 is stopped in the closed state, the rear cover 24 is firmly fixed together with the lower upper door 38 so that the rear end 30 and the lower upper part of the rear cover 24 are fixed. Substantially no gap is formed between the bottom 44 of the door 38.

In the open state of the pawl assembly 8 as shown in FIG. 2, as the rear end 30 of the rear cover 24 moves rearward, the lower upper door 38 is vertical in a vertical stationary state. The rear cover 24 pushes the lower end 44 of the lower upper door 38 by the tab board 48 and the bolt 50 so as to be inclined about the center. Due to the operation mentioned above, a small gap 52 is formed between the rear end 30 of the rear cover 24 and the lower end 44 of the lower upper door 38. This small gap 52 allows piano notes to leak out of the casing of the upright piano. This increases the volume of the piano. In accordance with the opening operation of the pole cover, the bolt 50 is not detached from the tab hole of the tab board 48, so that the rear cover 24 and the lower upper door 38 only move inside the casing of the upright piano.

In order to play the upright piano, when the user opens or closes the pole cover of the pole assembly 8, the lower upper door 38 opens or closes in response. In the open state of the pawl assembly 8, the small gap 52 is formed between the rear end 30 of the rear cover 24 and the lower end 44 of the lower upper door 38 and the pawl assembly ( The gap 52 disappears when 8) is closed.

Next, an example of a damping mechanism as disclosed in the above-mentioned European patent application EP 0697541 A1 will be described.

3 shows a selected component in the configuration of the damping mechanism 112, which includes a rotary damper 120, an arm 140 and a support base 142. As shown in FIG. The arm 140 may be rotatable about the rotary damper 120, and the rotary damper 120 is integrally formed with the support base 142. The lower surface of the support base 142 is fixed to the wooden part 152 of the piano by suitable fixing means such as double-sided tape or wood screws. The roller 146 attached to the tip of the arm 140 is freely rotatable with respect to the arm 140. The roller 146 is usually in contact with the inner surface of the upper cover 18 of the pole cover of the piano, the lower end of the arm 140 is a pair of arm support (rotationally supported by the rotary damper 120 ( 148). The rotary damper 120 is formed with a shaft 124 having a square end, which is fixed to the arm support 148, respectively. As the arm 140 rotates, the square shaft 124 of the rotary damper 120 is rotated.

In FIG. 3, a detailed description of the leaf spring hooked to the back of the arm 140 at the bottom of the support base 142 is omitted. The leaf spring (not shown) is elastic, which forces the arm 140 to move normally in the open direction. Due to the restoring force of the leaf spring, when a user or player starts to open the pole cover of the pole assembly 8, the arm 140 pushes the top cover 18 upwards to help the pole cover open. When the user or player closes the pole cover of the pole assembly 8, the leaf spring applies a load to the arm 140 with resistance to the closure of the pole cover, allowing the pole cover to close slowly and gently.

4 shows a detailed configuration of a rotary damper 120 with a shaft 124 including a cylindrical casing 123. The center O of the cross section of the shaft 124 coincides with the center of the cylinder of the casing 123. The casing 123 has an inner space filled with a viscous fluid 122 having a high viscosity such as grease. A casing blade 123a is integrally formed in the casing 123, and the casing blade 123a protrudes inwardly from the casing 123 and is formed to extend in the longitudinal direction of the casing 123. have. The casing blade 123a functions as a stopper for keeping the rotation of the rotating member 125 having the shaft 124 constant.

The shaft 124 is formed with a support protrusion 126 for supporting the moving valve 127 to rotate freely, the support protrusion 126 is formed to extend in the longitudinal direction of the shaft 124. In general terms, the support protrusion 126 has a circular cross-sectional shape. 4 only shows a single support protrusion 126 integrally formed with the shaft 124, it is possible to form a plurality of support protrusions with respect to the shaft 124.

The moving valve 127 carries a fluid passage 134 through which the viscous fluid 122 can move in response to the rotation of the rotating member 125, which is shown in FIG. 5. 4 shows that the flow valve 127 is positioned in tight contact with the inner wall of the casing 123 so that the fluid passage 134 does not perform its function. In response to the action of the pole cover of the open or closed pole assembly 8, the rotating member 125 rotates about its axis, so that the transfer valve 127 resists the resistance generated by the viscous fluid 122. And slide around the support protrusion 126 along a predetermined circular trajectory.

When the user or player closes the pole cover of the pole assembly 8, the shaft 124 rotates in the counterclockwise direction A inside the casing 123, as shown in FIG. In this case, the viscous fluid 122 supplies resistance to the transfer valve 127. Because of this resistance, the moving valve 127 moves and rotates clockwise so as to be in tight contact with the inner wall of the casing 123. Here, the viscous fluid 122 flows through the narrow gap 130 between the tip of the casing blade 123a and the outer wall of the shaft 124. The flow rate of the viscous fluid 122 is low, resulting in high rotational torque. In short, when the user or player closes the pole cover, the damping effect acts on the pole assembly 8.

On the contrary, when the rotating member 125 is rotated in the clockwise direction B inside the casing 123 as shown in FIG. 5, the moving valve 127 is subjected to the resistance generated by the viscous fluid 122. It rotates and moves about the support protrusion 126 counterclockwise. In this case, the moving valve 127 is separated from the inner wall of the casing 123 so that the fluid passage 134 forms a gap at a predetermined distance from the inner wall of the casing 123. This gap allows the viscous fluid 122 to flow smoothly into the casing 123. In short, the damping effect on the pawl assembly 8 is weakened when the user or player opens the pawl cover.

In the above-mentioned damping mechanism, the moving valve 127 slides on the support protrusion 126 having a circular cross-sectional shape along a predetermined circular trajectory. Since the cross-sectional shape of the support protrusion does not need to be circular, it is also possible to design a support protrusion having a rectangular cross-sectional shape. That is, it is also possible to modify the damping mechanism such that the moving valve 127 slides over the rotating member 125 in its radial direction in response to the movement of the fluid inside the casing 123.

Next, an example of a pole mechanism as disclosed in the above-mentioned European patent application EP 0901117 A2 will be described. FIG. 6 shows a part constituting the rear end of the pawl assembly 8, the pawl cover being rotatably connected to the rear cover 24 by a strap hinge 28. Close to the strap hinge 28, the rotary damper 213 is provided to prevent the pole cover of the pole assembly 8 from being closed coarse, and the damper case 213m of the rotary damper 213 is a piano. Is embedded in the inner wall of the side arm 4, and is fixed with a screw 215.

The rotary damper 213 is operated using the viscous resistance of the fluid therein, that is, the rotary damper 213 includes a rotary shaft 213n rotatably freely inside the damper case 213m having a cylindrical shape. This is illustrated in Figs. 7A to 7C. The cross-sectional shape of the rotary shaft 213n does not coincide with a complete circle, but is partially cut by a sector, and an incompressible damping oil 213z is enclosed therein. The sector space inside the damper case 213 is divided into two chambers, that is, the damping chambers 213v and 213w, by the partition wall 213u protruding inward from the inner wall of the damper case 213m.

The first damping chamber 213v and the second damping chamber 213w communicate with each other by a communication hole 213xa formed in a selected portion of the partition wall 213u. The partition wall 213u is provided with a check valve 213y for closing the communication hole 213xa. Further, a projection 213t having an arcuate cross section is formed on the rotation shaft 213n. When the rotation shaft 213n rotates about the central axis AX2 in the clockwise direction from the inside of the damper case 213m, the check valve 213y moves the communication hole 213xa as shown in FIGS. 7A to 7C. To open. The check valve 213y allows the damping oil 213z to smoothly flow between the first and second damping chambers 213v and 213w through the communication hole 213xa. On the contrary, when the rotation shaft 213n rotates in the counterclockwise direction, the check valve 213y moves in the communication hole 213xa in response to the flow of the damping oil 213z generated by the counterclockwise rotation of the rotation shaft 213n. To close.

In this case, the damping oil 213z is disposed between the first and second damping chambers 213v and 213w through a gap 213xb formed between the arc-shaped outer surface of the protrusion 213t and the tip of the dividing wall 213u. Will flow. Due to the small flow rate of the damping oil 213z flowing through the gap 213xb, a relatively high rotational torque is generated in the rotation damper 213. Based on the operating principle of the rotary damper 213, the damping effect acts on the pole cover of the pole assembly 8 to be closed, which dampens when the user or player opens the pole cover of the piano.

The above-mentioned technique is a so-called deviation absorbing structure that is made to suppress noise in FIG. 6 or to prevent the occurrence of abrasion or damage due to the positional deviation between the strap hinge 28 and the rotational center of the rotary damper 213. To provide. Specifically, this deviation absorbing structure is embodied as the deviation absorbing member 218 which engages with the engaging member 217 fixed to the side wall of the rear end of the pawl assembly 8. Therefore, the rotation shaft 213n of the rotary damper 213 is engaged with the deviation absorbing member 218.

A pair of through holes 219 are formed through the coupling member 217, and the through holes 219 are positioned to coincide with a pair of tap holes 220 formed on the side wall of each pole cover. . It is possible to securely fasten the coupling member 217 to the side wall of the pawl assembly 8 using the fixing screw 216 inserted into the tab hole 220 through the through hole 219. The coupling member 217 is provided with a cylinder portion 217e having an inner space 217h into which the deviation absorbing member 218 is engaged to be inserted into the inner space 217h. Two projections 217j protruding from the inner circumferential wall of the inner space 217h are arranged in a straight line in opposite directions to each other. The central axis of the cylinder portion 217e approximately coincides with the center of rotation AX1 of the strap hinge 28 of the pawl assembly 8.

The deviation absorbing member 218 is formed such that the outer diameter of the cylinder shape is smaller than the inner diameter of the cylinder portion 217e of the coupling member 217, and one end of the deviation absorbing member 218 is formed at a position opposite to each other. The pair of grooves 218ra are partially cut out. When the deviation absorbing member 218 is engaged with the inner space 217h of the cylinder portion 217e, the grooves 218ra coincide with the projections 217j, respectively. Comparing the projection 217j, the groove 218ra is formed to extend slightly longer along the projection 217j in the inner space 217h so that the deviation absorbing member 218 slightly slides.

A passage (not shown) formed at the other end of the deviation absorbing member 218 extends in a direction perpendicular to the linear arrangement of the grooves 218ra. The protruding member 213a formed integrally with the rotation shaft 213n of the rotation damper 213 is formed to extend in a straight line to match the diameter of the rotation shaft 213n. When the rotary damper 213 is assembled to the deviation absorbing member 218, the protruding member 213a is engaged to allow the sliding motion freely in the passage mentioned above. That is, relative movement is realized along the direction in which the passage is formed long between the rotation shaft 213n of the rotary damper 213 and the deviation absorbing member 218. As described above, the assembly of the coupling member 217, the deviation absorbing member 218, and the rotation shaft 213n function as an oldham coupling.

Corresponding to the rotational operation of the pawl cover of the pawl assembly 8, which is opened or closed, the engagement member 217 moves with the pawl assembly 8. This mainly causes the deviation absorbing member 218 to move in the inner space 217h of the cylinder portion 217e, so that the rotation torque is transmitted to the rotation shaft 213n of the rotation damper 213. Therefore, the rotation shaft 213n rotates inside the damper case 213m fixed to the side arm of the piano. Thus, it is possible to obtain the damping effect described above with reference to FIGS. 7A to 7C. With the operation of the Oldham coupling, a positional deviation occurs between the rotation center AX1 of the strap hinge 28 of the pawl assembly 8 and the rotation center AX2 of the rotation damper 213n, but the attenuation effect is assured. Operate the mentioned parts smoothly. As a result, it is possible to suppress noise or to prevent abrasion or damage from occurring.

It goes without saying that various modifications to the upright piano of the present invention can be proposed within the scope of the invention. That is, the damping mechanism need not be limited in position as described in the embodiment of the present invention. For example, it is possible to include a damping mechanism for preventing the pole cover in contact with the bottom of the rear cover 24 from widening, and it is also possible to use various structures for the connecting member 46. This embodiment describes an upper door assembly comprising a fixed upper top door and an open lower top door. Instead of this configuration, it is also possible to construct the upper door assembly with one upper door which opens in conjunction with the opening of the pole cover of the piano.

This invention can be implemented in other various forms, without deviating from the mind or main characteristic. For this reason, the present embodiment is merely a mere example in all respects and should not be interpreted limitedly. The scope of the present invention is shown by the claims, and the present specification is not limited thereto. In addition, all the modifications and changes which belong to the equal range of a claim are within the scope of the present invention.

Claims (14)

Keyboard (2); A pole assembly (8) having a pole cover (20, 18, 24) for covering the keyboard; A keyboard musical instrument, characterized in that it consists of an upper door assembly (14) having an upper door (36, 38) to be opened. Keyboard (2); A pole assembly (8) having a pole cover (20, 18, 24) for covering the keyboard; And an upper door assembly (14) having an upper door (36, 38) and connected to said pole assembly (8) to automatically open said upper door according to the operation of the pole cover being opened. Keyboard (2); A pole assembly (8) having a pole cover (20, 18, 24) for covering the keyboard; Keyboard instrument characterized in that the upper door (36, 38) is provided, consisting of an upper door assembly (14) connected to the pole assembly (8) such that the upper door is stopped in a closed state in accordance with the operation of the closed pole cover. . The keyboard musical instrument as claimed in claim 1, wherein the upper door assembly is connected to the pawl assembly via a bag hollow assembly. A back hole according to any one of the preceding claims, wherein the upper door assembly is provided with a rear cover (24) connected to the pawl assembly (8) by a pivot mechanism (23) while simultaneously sliding in a sliding manner. Keyboard instrument, characterized in that connected to the pole assembly (8) via the right assembly (12). A back hole according to any one of the preceding claims, wherein the upper door assembly is provided with a rear cover (24) connected to the pawl assembly (8) by a pivot mechanism (23) while simultaneously sliding in a sliding manner. Keyboard assembly characterized in that connected to the pole assembly (8) via the right assembly (12), by the connecting member (46). 4. The keyboard musical instrument as claimed in claim 1, wherein the upper door of the upper door assembly is level and rotates about a rotation axis arranged on the upper part of the case assembly. 6. 4. The predetermined distance according to any one of claims 1 to 3, wherein the upper door of the upper door assembly is horizontal and is defined between the closed position and the open position with respect to the rotational axis disposed on the upper part of the case assembly (6). And, wherein the top door is positioned vertically in the closed position while inclined backward in the open position. 4. The predetermined distance according to any one of claims 1 to 3, wherein the upper door of the upper door assembly is horizontal and is defined between the closed position and the open position with respect to the rotational axis disposed on the upper part of the case assembly (6). Keyboard instrument characterized in that it has a small gap 52 which rotates within the range and is formed near the bottom of the upper door when the upper door is inclined backward in the open state and closed when the upper door is closed in the closed position. . 4. The upper door assembly according to any one of the preceding claims, wherein the upper door assembly has a fixed upper upper door (36) and a lower side that is horizontal and rotates about a rotation axis disposed on the upper part of the case assembly (6). Keyboard instrument, characterized in that consisting of an upper door (38). 4. The upper door assembly of claim 1, wherein the upper door assembly comprises a lower upper door 38 that operates with a fixed upper upper door 36, wherein the lower upper door is in contact with an upper upper door. The keyboard musical instrument, characterized in that it rotates relative to the strap hinge 42 provided between. 4. A damping mechanism (112, 120, 213) according to any one of the preceding claims, further comprising a damping mechanism (112, 120, 213) for attenuating the operation of the pole cover of the closed or open pole assembly (8). Keyboard musical instrument. Keyboard (2); Pole assembly (8) having pole covers (20, 18, 24) to cover the keyboard; The pawl assembly 8 is provided with upper doors 36 and 38, and through the bag hollow assembly 12, which rotates in accordance with the operation of the pawl cover of the pawl assembly 8, in which the upper door is closed or opened. An upper door assembly 14 connected to the pawl cover to open a small gap 52 near the bottom of the upper door; A keyboard musical instrument comprising a damping mechanism (112, 120, 213) for distributing a resistive load to a closed or open pole cover. 14. The damping mechanism according to claim 13, wherein the damping mechanism includes a rotary damper (120, 213) containing a viscous fluid (122, 213z) flowing to generate torque to automatically distribute the increased load to the closed pole cover. Key musical instrument characterized by.