Keyboard mechanism of a keyboard instrument

Abstract

The present invention provides a keyboard mechanism for a keyboard instrument that ensures proper operation of the action unit even if the action unit holder is misaligned in the front-to-back direction during manufacturing, thereby providing a good touch feel and appropriate timing for sound production when pressing keys. [Solution] The keyboard device 1 comprises a swingable key 2, an action unit 6 that performs a predetermined operation in conjunction with pressing the key, a hammer support 4 positioned behind the key, and a hammer 5 that is rotatably supported by the hammer support and mounted on the action unit. The action unit comprises a holder 51 fixed to the rear end of the key, and a repetition lever 52 and a jack 53 that are rotatably attached to the holder 51. The jack stopper 36 of the hammer support is inclined downwards and has a contact surface 36a that the rear end of the jack 53 contacts from below when the key is pressed.

Description

Technical Field

[0001] The present invention relates to a keyboard device of a keyboard instrument such as an electronic piano, and particularly to a keyboard device of a keyboard instrument that realizes an action similar to that of a grand piano.

Background Art

[0002] Conventionally, as this type of keyboard device, for example, the one described in Patent Document 1 already filed by the applicant is known. This keyboard device has a key that extends in the front-rear direction and is swingable about a fulcrum at the center in the length direction. An action unit that executes a predetermined operation in conjunction with the key depression is attached to the rear part of this key. This action unit has a holder attached to the key, and a repetition lever and a jack rotatably supported by this holder. The repetition lever is formed in a predetermined shape extending in the front-rear direction, and is rotatably supported by the holder through a fitting hole provided in the front part, and a jack guide hole is provided behind the fitting hole. On the other hand, the jack is rotatably supported by the holder through a fitting hole provided in the lower part, and has a hammer lifting part and a rear arm extending upward and rearward from the fitting hole respectively. The hammer lifting part is engaged in a state of being inserted downward into the jack guide hole of the repetition lever.

[0003] Also, a hammer support is arranged on the rear side of the key, and a hammer extending in the front-rear direction is rotatably supported by the hammer support at its rear end. Further, the hammer has a hammer protrusion protruding downward at its rear part, and the hammer protrusion is placed above the jack guide hole on the upper surface of the repetition lever.

[0004] In the keyboard mechanism configured as described above, when a key is pressed, the holder at the rear end of the key rises, and the repetition lever and jack move upward together with it. Consequently, the repetition lever first pushes up the hammer via the hammer projection, causing it to rotate upward. Next, the rear end of the repetition lever locks into place by contacting the horizontal repetition stopper of the hammer support from below, causing the jack to push up the hammer projection via the hammer thrusting part, causing the hammer to rotate upward. Just before the hammer rotates to press the key switch, the rear end of the jack's rear arm contacts the horizontal jack stopper of the hammer support from below, causing the hammer thrusting part of the jack to disengage from the hammer projection (escapement). This escapement of the jack releases the hammer from the action unit, allowing it to rotate freely, press the key switch, and produce a piano sound. Furthermore, when the jack escapes, a click sensation is produced due to the change in the touch weight of the key, which provides a sense of let-off in the player's touch when playing a keyboard instrument. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2024-93320 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The above keyboard mechanism may experience the following malfunctions due to manufacturing issues. Specifically, when the action unit is attached to the rear end of a key during manufacturing, the holder may be misaligned in the front-to-back direction relative to the key. For example, if the holder is attached further back than the correct position, the rear end of the rear arm of the jack will also be positioned further back. In this case, the rear end of the rear arm, which rises with each key press, will rise earlier and higher. As a result, the timing at which the rear end of the rear arm contacts the jack stopper from below becomes earlier, and the subsequent amount of rotation of the jack increases. Consequently, the hammer thrust portion of the jack rotates earlier and further back, causing the let-off timing (when the hammer escapes from the hammer projection) to be earlier, and the height to which the hammer reaches when it is pushed up to be lower.

[0007] On the other hand, if the holder is mounted further forward than the correct position, the opposite will occur: the timing at which the rear end of the rear arm contacts the jack stopper from below will be delayed, resulting in a delayed let-off timing.

[0008] As described above, if the mounting position of the action unit holder is shifted in the front-to-back direction from the correct position, the touch feel and sound timing when pressing the key may also be affected.

[0009] The present invention was made to solve the above-mentioned problems, and aims to provide a keyboard device for a keyboard instrument that can ensure the proper operation of the action unit even when the holder of the action unit attached to the rear end of the key is mounted misaligned in the front-rear direction from the proper position during the manufacturing of the keyboard device, thereby providing a good touch feel and appropriate sound timing when pressing the key. [Means for solving the problem]

[0010] To achieve the above objective, the invention according to claim 1 comprises: a key extending a predetermined length in the front-rear direction and pivotable with a pivot point near the center in the longitudinal direction; an action unit provided at the rear of the key and performing a predetermined operation in conjunction with the pressing of the key; a hammer support positioned at the rear of the key; and a hammer extending a predetermined length in the front-rear direction and rotatably supported at its rear end via a hammer support shaft extending in the left-right direction of the hammer support, and mounted on the action unit via a hammer projection provided so as to protrude downward immediately in front of the hammer support shaft, and driven upward via the action unit in conjunction with the pressing of the key, wherein the action unit comprises a holder fixed to the rear end of the key, and an upper surface formed in a predetermined shape extending in the front-rear direction and rotatably attached to the holder, with a hammer projection mounted on the upper surface having a jack guide hole that penetrates in the vertical direction and extends in the front-rear direction, and as the key is pressed it rises, the hammer is pushed up via the hammer projection. The hammer support has a jack that rotates upward, a hammer thrusting portion that extends vertically, and a rear arm that extends rearward from near the lower end of the hammer thrusting portion, and is rotatably mounted on a holder, the upper end of the hammer thrusting portion is inserted from below into the jack guide hole of the repetition lever and engages so as to be movable in the front-rear direction, and a jack that thrusts the hammer upward via the hammer projection portion by the hammer thrusting portion as the repetition lever rises in conjunction with the pressing of the key, and rotates the hammer upward, and the hammer support has a jack stopper that locks the jack when the rear end of the rear arm abuts against it from below as the hammer is thrust upward by the jack, and rotates the jack using the abutting rear end of the rear arm as a pivot point, thereby disengaging the hammer thrusting portion of the jack from the hammer projection portion of the hammer, and the jack stopper is characterized by being inclined downwards and having a contact surface that the rear end of the rear arm can abut against from below.

[0011] In this configuration, an action unit is provided at the rear of the key, and a hammer, whose rear end is rotatably supported on the hammer support shaft of the hammer support, is mounted on the action unit via a hammer projection immediately in front of the hammer support shaft. This action unit comprises a holder fixed to the rear end of the key, and a repetition lever and a jack rotatably attached to this holder. The hammer thrust portion of the jack is inserted from below into the jack guide hole of the repetition lever and engages with it so as to be movable in the front-rear direction, and the hammer is mounted on the upper surface of the repetition lever, where the jack guide hole is provided, via a hammer projection.

[0012] When the key is pressed, the front end of the key is pushed down, causing the rear end of the key to move upward together with the holder of the action unit. Consequently, the repetition lever of the action unit rises, pushing up the hammer via the hammer projection and rotating it upward. Also, as the repetition lever rises, the hammer-pushing part of the jack pushes up the hammer via the hammer projection and rotates it further upward. While the hammer is being pushed up by the jack, the rear end of the jack's rear arm contacts the jack stopper of the hammer support from below, locking the jack in place and causing the jack to rotate using the contacting rear end of the rear arm as a pivot point, thereby disengaging the hammer-pushing part of the jack from the hammer projection. In other words, the jack escapes from the hammer. This escape of the jack releases the hammer from the action unit and the key, allowing it to rotate freely upward. During this escape of the jack, a click sensation is created due to the abrupt increase or decrease in the touch weight of the key, thereby providing the player with a let-off sensation.

[0013] As described above, in the operation of the action unit when a key is pressed, the rear end of the rear arm of the jack contacts the contact surface of the jack stopper on the hammer support from below. The contact surface of this jack stopper is configured to be inclined downwards towards the front. If the contact surface of the jack stopper is configured to be horizontal, and the holder of the action unit attached to the rear end of the key is mounted further back than the correct position during the manufacturing of the keyboard device, the timing at which the rear end of the rear arm of the jack contacts the contact surface of the jack stopper will be earlier. Conversely, if the holder is mounted further forward than the correct position, the timing will be delayed. Therefore, according to the present invention, since the contact surface of the jack stopper is configured to be inclined downwards towards the front, even if the holder of the action unit attached to the rear end of the key is mounted shifted in the front-rear direction relative to the correct position during the manufacturing of the keyboard device, the rear end of the rear arm of the jack can contact the contact surface of the jack stopper at the appropriate timing, thereby providing a good touch and appropriate sound timing when pressing the key. [Brief explanation of the drawing]

[0014] [Figure 1] The image shows a part of the keyboard mechanism of an electronic piano to which a keyboard mechanism according to one embodiment of the present invention is applied, where (a) is a perspective view and (b) is a right side view. [Figure 2] (a) is a perspective view showing the action unit assembled to the key and the hammer mounted on top thereof, and (b) is a perspective view showing the key, action unit, and hammer disassembled. [Figure 3] This is a perspective view showing the hammer support; (a) is an external view, and (b) is a view showing a portion of it cut out. [Figure 4] This diagram shows a hammer support, with (a) being a front view and (b) being a cross-sectional view along line AA. [Figure 5] This is a magnified perspective view of the hammer and action unit, with (a) showing the action unit with all its components assembled and (b) showing the action unit with all its components disassembled. [Figure 6] It is a right side view showing a hammer. [Figure 7] It is a right side view showing a holder. [Figure 8] (a) is a right side view showing a repetition lever, and (b) is a right side view showing a repetition lever of a modified example. [Figure 9] (a) is a right side view showing a jack, and (b) is a right side view showing a jack of a modified example. [Figure 10] It is an explanatory diagram for sequentially explaining the operations of the action unit and the hammer when pressing a key. (a) shows the key-released state, and (b) shows the state where the repetition lever abuts against the repetition stopper when pressing the key. [Figure 11] It is an explanatory diagram following FIG. 10. (a) shows the state where the jack abuts against the jack stopper, and (b) shows the state where the jack has come out from the hammer protrusion. [Figure 12] It is an explanatory diagram following FIG. 11. (a) shows the state where the hammer abuts against the hammer stopper, and (b) shows the state where the hammer bounces back from the hammer stopper and abuts against the back check. [Figure 13] It is an explanatory diagram following FIG. 12. (a) shows the state where the jack has rotated under the hammer protrusion as the pressed key is slightly returned, and (b) shows the state where the key has returned to the original key-released state.

Mode for Carrying Out the Invention

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a part of the keyboard device of an electronic piano to which the keyboard device according to an embodiment of the present invention is applied, in the key-released state. (a) is a perspective view, and (b) is a right side view.

[0016] As shown in the figure, the keyboard device 1 includes a large number of keys 2 arranged in the left - right direction of an electronic piano (only one white key is shown in FIG. 1), a keyboard chassis 3 that supports these keys 2, a hammer support 4 connected to the rear end portion of this keyboard chassis 3, a hammer 5 provided for each key 2 and rotatably supported by the hammer support 4, an action unit 6 provided at the rear end portion of the key 2 that drives the hammer 5 upward as the key is pressed, a key switch 7 for detecting key - pressing information of the key 2, and the like.

[0017] As shown in FIG. 1, the keyboard chassis 3 is composed of three support rails 10 including a front rail 11, a middle rail 12, and a rear rail 13 that all extend in the left - right direction and are arranged at a predetermined interval in the front - rear direction (the left - right direction in FIG. 1(b)), and a plurality (for example, five) of reinforcing ribs 14 (only one is shown in FIG. 1) that extend in the front - rear direction and are arranged at a predetermined interval in the left - right direction. These support rails 10 and ribs 14 are assembled in a grid - like shape. These support rails 10 and ribs 14 are composed of iron plates formed into a predetermined shape by punching and bending processes, for example, by pressing, and are connected to each other by screwing.

[0018] The front rail 11 has a horizontal top plate portion 11a, a front plate portion 11b that bends downward at a right angle from the front end portion of this top plate portion 11a, and a bottom plate portion 11c that bends backward at a right angle from the lower end portion of this front plate portion 11b. On the lower surface of the top plate portion 11a, a front guide 15 is fixed by screwing or the like. The front guide 15 is formed in a thick plate shape made of synthetic resin and extends in the left - right direction over the entire front rail 11. A large number of front pins 16 are erected at front - rear positions corresponding to the white keys 2 and black keys (not shown) in a state of passing through the top plate portion 11a of the front rail 11 and arranged in the left - right direction.

[0019] The central rail 12 has a horizontal reed mounting section 12a, the front and rear ends of which are bent upward at right angles. The reed 17 is mounted on the reed mounting section 12a and fixed in place by screws or the like. The reed 17 is formed in the shape of a thick plate made of synthetic resin and extends in the left-right direction across the entire central rail 12. Numerous balance pins 18 are erected on the reed 17 in a left-right direction at front and rear positions corresponding to the white keys 2 and black keys.

[0020] The rear rail 13 has a receiving recess 13a that opens upward and engages with the lower part of the hammer support 4 while it is housed there, a cushion mounting portion 13b that bends at a right angle from the upper end of the front plate portion of the receiving recess 13a and extends horizontally forward, with a cushion 19 that extends in the left-right direction placed on it, and a connecting portion 13c that drops down one step from the front end of the cushion mounting portion 13b and extends horizontally further forward. Multiple mounting holes that penetrate in the front-rear direction are formed in the front plate portion of the receiving recess 13a, and the lower end of the hammer support 4 is screwed to the rear rail 13 through these mounting holes. The receiving recess 13a and the connecting portion 13c are also screwed to the rear end of each rib 14.

[0021] Figure 2(a) shows the action unit 6 assembled to the key 2 and the hammer 5 placed on top of it, and Figure 2(b) shows the key 2, action unit 6 and hammer 5 disassembled. As shown in the figure, the key 2 has a wooden key body 21 that extends a predetermined length in the front-rear direction and has a rectangular cross-section, and a synthetic resin key cover 22 that is bonded to the upper surface and front of the front half of the key body 21. A balance pin hole 23 that penetrates vertically is formed near the center of the length of the key body 21, and the key 2 is pivotably supported by a balance pin 18 erected in the reed 17 via this balance pin hole 23.

[0022] The balance pin hole 23 described above is formed as a nearly circular hole near the bottom surface of the key body 21, and the entire upper part connected to the hole is formed as an elongated hole extending in the longitudinal direction of the key body 21. Furthermore, felt 23a is provided on the left and right inner surfaces of the balance pin hole 23 to allow smooth sliding against the balance pin 18 when the key 2 swings. In addition, a cushion 20 is attached to the rear side of the balance pin hole 23 on the top surface of the key body 21, and this cushion 20 prevents the front end of the hammer 5 from directly hitting the key 2 during maintenance, etc.

[0023] Furthermore, a front pin hole 24 (see Figure 1(b)) that opens downward is formed at a predetermined position on the front of the key body 21. This front pin hole 24 engages with a front pin 16 erected on the reed front 15, thereby preventing the key 2 from swinging in the left-right direction.

[0024] Furthermore, as shown in Figure 2(b), a guide groove 21a is formed at the rear end of the key body 21, which penetrates vertically and opens to the rear. This guide groove 21a has a predetermined width in the left-right direction and, in a plan view, is formed to extend a predetermined length in the front-rear direction parallel to the left side surface of the key body 21. The guide groove 21a formed in this way is used to attach the holder 51 of the action unit 6, which will be described later, to the rear end of the key body 21 in the correct position.

[0025] Figures 3 and 4 show the hammer support 4. As shown in both figures, the hammer support 4 is made of molded parts made of synthetic resin, and multiple molded parts for, for example, one octave worth are connected to each other in the left-right direction and screwed to the rear rail 13 of the keyboard chassis 3. The hammer support 4 consists of a hammer support part 31 that rises upright from near the rear rail 13 and a switch mounting part 32 that extends diagonally upward from its upper end. A hammer support shaft 33 is provided at the upper end of the hammer support part 31 to rotatably support each hammer 5.

[0026] Furthermore, the hammer support 4 has multiple partition walls 34 that separate adjacent hammers 5 at predetermined intervals from each other in the left-right direction, and the hammer support shaft 33 extends in the left-right direction between adjacent partition walls 34, 34. As shown in the enlarged view in Figure 4(b), the hammer support shaft 33 has a so-called oval cross-sectional shape, with two cutouts at the front and back of a circle centered on the axis of the hammer support shaft 33.

[0027] Specifically, the outer surface of the hammer shaft 33 is composed of a pair of upper and lower curved portions 33a, 33a and a pair of front and rear flat portions 33b, 33b extending between these curved portions 33a, 33a. In the hammer shaft 33 configured in this way, the upper and lower curved portions 33a, 33a are set in the shape of an arc with a diameter of length L1, while the distance between the front and rear flat portions 33b, 33b is set to a length L2 that is shorter than the aforementioned length L1.

[0028] Furthermore, as shown in Figure 1, a key switch 7 is attached to the switch mounting portion 32 of the hammer support 4. This key switch 7 consists of a switch board 7a made of a printed circuit board and a switch body 7b made of a rubber switch attached to the hammer 5 side of the switch board 7a for each key 2.

[0029] Furthermore, as shown in Figures 3 and 4, a repetition stopper 35 is provided on the rear side of the hammer support 4, diagonally below and behind the hammer pivot shaft 33, to which the repetition lever 52 of the action unit 6 (described later) will strike and lock when pressed. This repetition stopper 35 is inclined downwards and forwards and has a contact surface 35a against which the repetition lever 52 strikes. A cushion such as felt may be attached to this contact surface 35a to suppress noise and vibration when the repetition lever 52 strikes.

[0030] Furthermore, on the rear side of the hammer support 4, below the repetition stopper 35, there is a jack stopper 36 that the jack 53 of the action unit 6 (described later) contacts and locks when pressed. Similar to the repetition stopper 35 described above, this jack stopper 36 is inclined downwards and has a contact surface 36a that the jack 53 contacts. A cushion such as felt may also be attached to this contact surface 36a to suppress noise and vibration when the jack 53 contacts it.

[0031] Furthermore, as shown in Figure 1, a hammer stopper 38 is provided at the upper front end of the hammer support 4. When the hammer 5 rotates upward, the hammer stopper 38 makes contact with it from below, preventing it from rotating any further.

[0032] Figure 5 shows the hammer 5 and the action unit 6, where (a) shows the action unit 6 assembled and (b) shows the action unit 6 disassembled. Figure 6 is also a right side view of the hammer 5. As shown in these figures, the hammer 5 has an arm-shaped hammer body 41 that extends a predetermined length in the front-rear direction, and two weight plates 42, 42 attached to the front ends of its left and right sides. The hammer body 41 is made of synthetic resin, and the weight plates 42 are made of a metal material such as iron with a relatively high specific gravity.

[0033] The rear end of the hammer body 41 is provided with an engaging portion 43 that engages with the hammer support shaft 33 of the hammer support 4. This engaging portion 43 has an arc-shaped shaft hole 44 that penetrates in the left-right direction and has a C-shaped side profile, and its opening is formed to widen outward. The shaft hole 44 has a diameter slightly larger than the diameter (length L1) of the upper and lower curved portions 33a, 33a of the hammer support shaft 33, and the width L3 of the opening is slightly larger than the length L2 between the front and rear flat portions 33b, 33b of the hammer support shaft 33 and smaller than the aforementioned length L1. The hammer 5 is detachably attached to the hammer support shaft 33 of the hammer support 4 through the opening of the shaft hole 44, and is rotatably supported by the hammer support 4 when the shaft hole 44 fits onto the hammer support shaft 33.

[0034] Furthermore, a switch pressing portion 45 and a hammer protrusion portion 46 are provided above and below the shaft hole 44 at the rear of the hammer 5. The upper surface of the switch pressing portion 45 is formed flat, and when the hammer 5 rotates upward, it presses the switch body 7b of the key switch 7, thereby detecting the key press information of the key 2 corresponding to the hammer 5.

[0035] On the other hand, the hammer projection 46 corresponds to the shank roller in the hammer of a grand piano. This hammer projection 46 is constructed by attaching a roller bush 49 made of an elastic material to a projection body 48 which is molded integrally with the hammer body 41.

[0036] Then, in the unlocked state, the hammer projection 46 is placed on the hammer mounting portion 74 of the repetition lever 52 of the action unit 6, which will be described later.

[0037] Furthermore, as shown in Figures 5 and 6, a backcheck engaging portion 47 is provided at a predetermined position on the front of the hammer 5. This backcheck engaging portion 47 is integrally molded with the hammer body 41, protrudes downward, and can engage with the backcheck 62 of the action unit 6, which will be described later. As shown in Figure 6, the backcheck engaging portion 47 has a vertically elongated side shape, a flat front surface, and a gently curved back surface.

[0038] Next, the action unit 6 will be described. As shown in Figure 5, the action unit 6 comprises a holder 51 fixed to the rear end of the key 2, a repetition lever 52 and a jack 53 rotatably attached thereto, and a repetition spring 54 and a jack spring 55, both made of coil springs, which bias these to rotate in a predetermined direction.

[0039] Figure 7 shows a right side view of the holder 51. As shown in Figure 7 and Figure 5, the holder 51 is made of synthetic resin and is a molded product of a predetermined shape that extends in the front-rear direction. The holder 51 includes a key mounting portion 61 provided at the front and fixed to the rear end of the key 2, a back check 62 provided above it, a repetition support shaft 63 provided at the upper end near the center in the front-rear direction and rotatably supporting the repetition lever 52, and a jack support shaft 64 provided at the rear end and rotatably supporting the jack 53.

[0040] The key mounting section 61 has a U-shaped side profile formed by an upper wall 61a, a rear wall 61b, and a lower wall 61c, with the left ends of these walls connected by a left side wall 61d. The key mounting section 61 is also provided with a guide rib 60 that protrudes forward from the rear wall 61b for a predetermined length. This guide rib 60 is formed in a flat plate shape with a predetermined thickness, has a gap between it and the upper wall 61a and the lower wall 61c, and is positioned parallel to the left side wall 61d at a predetermined distance.

[0041] When the holder 51 is attached to the rear end of the key 2, the guide rib 60 of the holder 51 is inserted from the rear into the guide groove 21a of the key body 21 (see Figure 2(b)), and the upper wall 61a and left side wall 61d of the holder 51 are fixed by adhesive in contact with the upper and left sides of the rear end of the key body 21, respectively. In addition, staples (not shown) are driven in from above the upper wall 61a and to the left of the left side wall 61d of the holder 51. As a result, the holder 51 is firmly fixed to the rear end of the key body 21.

[0042] The back check 62 has a predetermined length in the vertical direction and is formed in a gentle arc shape, facing diagonally upward and forward. Furthermore, the back check 62 is configured to lock into the back check engagement portion 47 of the hammer 5 by sliding it against it when the hammer 5 engages with the back check engagement portion 47.

[0043] Both the repetition shaft 63 and the jack shaft 64 are formed in a cylindrical shape with a predetermined diameter and protrude to the right by a predetermined length. Furthermore, the repetition shaft 63 is formed at a predetermined position higher than the jack shaft 64.

[0044] Furthermore, the holder 51 is provided with a repetition spring locking portion 65 that locks the upper end of the repetition spring 54 at a predetermined position in front of the repetition shaft 63, between the back check 62 and the repetition shaft 63. In addition, the holder 51 is provided with a jack spring locking portion 66 that locks the upper end of the jack spring 55 at a predetermined position in front of the jack shaft 64, between the repetition shaft 63 and the jack shaft 64.

[0045] Figure 8(a) shows a right side view of the repetition lever 52. As shown in Figures 8(a) and 5, the repetition lever 52 is made of synthetic resin and is a molded product of a predetermined shape that extends in the front-rear direction. The repetition lever 52 includes a fitting hole 71 that penetrates in the left-right direction and is rotatably fitted onto the repetition support shaft 63 of the holder 51, a front arm 72 that extends forward from near the fitting hole 71, and a hammer mounting arm 73 that is formed to extend rearward from near the fitting hole 71 and on which the hammer 5 is mounted and which the jack 53 engages.

[0046] The hammer mounting arm 73 of the repetition lever 52 has a side shape that includes a hammer mounting portion 74 that extends a predetermined length diagonally upward and rearward from the fitting hole 71, and an extension portion 75 that extends diagonally downward and rearward from the rear end of the hammer mounting portion 74 and further rearward. In addition, the hammer mounting arm 73 has a jack guide hole 73a that penetrates in the vertical direction and extends in the front-rear direction across the hammer mounting portion 74 and the extension portion 75.

[0047] Furthermore, the rear end of the repetition lever 52 is provided with a projection 76 that protrudes upward. When the repetition lever 52 rotates, the upper part of the projection 76 contacts the repetition stopper 35 from below. In Figure 8(a), the upper part of the projection 76 is shown to have a flat surface 76a, but for example, as shown in Figure 8(b), the upper part of the projection 76 may be formed to have an inclined surface 76b that slopes downwards at the front, similar to the contact surface 35a of the repetition stopper 35. In this case, when the repetition lever 52 rotates and contacts the repetition stopper 35, the entire inclined surface 76b contacts the contact surface 35a.

[0048] Figure 9(a) shows a right side view of the jack 53. As shown in Figures 9(a) and 5, the jack 53 is made of synthetic resin and is composed of a molded product of a predetermined shape. The jack 53 has a fitting hole 81 that penetrates in the left-right direction and is rotatably fitted onto the jack support shaft 64 of the holder 51, a front arm 82 that extends forward from near the fitting hole 81, a hammer thrusting portion 83 that extends upward for a predetermined length from near the fitting hole 81, and a rear arm 84 that extends backward from near the fitting hole 81.

[0049] The hammer thrust portion 83 extends diagonally upward and forward at a predetermined angle, relative to the front arm 82 and rear arm 84, which extend almost horizontally in the front-rear direction. The upper end of the hammer thrust portion 83 is formed to be narrower in the front-rear direction than the lower portion. The rear end of the rear arm 84 is provided with a projection portion 84a that protrudes upward. When the jack 53 rotates, the projection portion 84a contacts the jack stopper 36 from below. In Figure 9(a), the side shape of the projection portion 84a is shown to be arc-shaped, but for example, as shown in Figure 9(b), the rear end of the rear arm 84 may be formed to have an inclined surface 84b that slopes downward forward, similar to the contact surface 36a of the jack stopper 36. In this case, when the jack 53 rotates and contacts the jack stopper 36, the entire inclined surface 84b contacts the contact surface 36a.

[0050] Furthermore, in the jack 53, plate-shaped reinforcing ribs 85a, 85b, and 85c are provided between the front arm 82 and the hammer thrusting section 83, between the hammer thrusting section 83 and the rear arm 84, and between the rear arm 84 and the front arm 82, respectively. These reinforcing ribs 85a to 85c enhance the strength of the jack 53.

[0051] In the action unit 6 formed as described above, as shown in Figure 5(a), the hammer thrust portion 83 of the jack 53 is engaged with the jack guide hole 73a of the repetition lever 52 when inserted from below. Also, as shown in the same figure, the front arm 72 of the repetition lever 52 is biased downward by the repetition spring 54, while the front arm 82 of the jack 53 is biased downward by the jack spring 55. As a result, the repetition lever 52 and the jack 53 are biased in a counterclockwise direction as shown in Figure 5(a), around the repetition support shaft 63 and the jack support shaft 64, respectively.

[0052] Next, referring to Figures 10 to 13, the operation of the action unit 6 and the hammer 5 when key 2 is pressed will be explained.

[0053] Figure 10(a) shows the keyboard device 1 in the unlocked state. In this unlocked state, the hammer 5 is placed on the hammer mounting portion 74 of the repetition lever 52 via the hammer projection 46, and the upper end of the hammer thrust portion 83 of the jack 53 faces the hammer projection 46 with a gap between them. Also, in the unlocked state, a gap is provided between the back check engaging portion 47 of the hammer 5 and the back check 62 of the holder 51.

[0054] When the front end of key 2 is pushed down from the unlocked state described above, key 2 swings downward and forward around the balance pin 18, and the rear end of key 2 moves upward. Consequently, the action unit 6 also moves upward together with the rear end of key 2, and the hammer 5 is pushed up by the repetition lever 52 via the hammer projection 46. As a result, the hammer 5 rotates upward (clockwise in Figure 10) around the hammer pivot shaft 33.

[0055] Next, as the key is pushed forward and the action unit 6 moves upward, as shown in Figure 10(b), the projection 76 at the rear end of the repetition lever 52 contacts the downward-sloping contact surface 35a of the repetition stopper 35 on the hammer support 4 from below. As a result, the rear end of the repetition lever 52 is locked, while the upper end of the hammer thrusting portion 83 of the jack 53 contacts the hammer projection 46 from below. As a result, the hammer 5 is thrust upward by the hammer thrusting portion 83 of the jack 53 and rotates further upward.

[0056] Next, as the key is pushed further and the action unit 6 moves further upward, as shown in Figure 11(a), the projection 84a at the rear end of the rear arm 84 of the jack 53 contacts the downward-sloping contact surface 36a of the jack stopper 36 on the hammer support 4 from below. As a result, with the rear end of the rear arm 84 locked, the jack 53 rotates clockwise in Figure 11(a) as the jack pivot shaft 64 moves upward, pivoting around the rear end of the rear arm 84. Consequently, as shown in Figure 11(b), the upper end of the hammer thrust portion 83 of the jack 53 moves backward and disengages from the hammer projection 46 of the hammer 5. This disengagement of the jack 53 releases the hammer 5 from the action unit 6 and the key 2, allowing it to rotate further upward in a state of free rotation.

[0057] Furthermore, when jack 53 escapes, a click sensation is produced due to the abrupt increase or decrease in the touch weight of key 2, thereby providing a let-off sensation to the player's touch.

[0058] Figure 12(a) shows the hammer 5, which has rotated upward, in contact with the hammer stopper 38 at the upper front end of the hammer support 4. In this case, the front part of the hammer body 41 of the hammer 5 contacts the hammer stopper 38 from below, preventing the hammer 5 from rotating any further. Also in this case, the switch pressing part 45 of the hammer 5 presses the switch body 7b of the key switch 7 from below, turning the key switch 7 ON. This detects key press information corresponding to the rotation speed of the hammer 5, and outputs it to a sound production control device (not shown). Based on this key press information, the sound production control device outputs piano sound from the speaker (not shown) of the electronic piano.

[0059] Figure 12(b) shows the state immediately after the hammer 5 contacts the hammer stopper 38, specifically, the state in which the hammer 5 bounces back from the hammer stopper 38 and rotates downward (counterclockwise) toward its original position before the key was pressed, and the back check engaging portion 47 of the hammer 5 is locked to the back check 62 of the holder 51. In this case, the hammer 5 is stopped as the back check engaging portion 47 slides against the back check 62, preventing it from rotating any further downward, and thus preventing rebound and vibration of the hammer 5.

[0060] Figure 13(a) shows the state in which the pressed-down key 2 has been released and returned slightly (for example, 1 / 3 of the key depth). When the key is released from the state shown in Figure 12(b) above, as shown in Figure 13(a), the front end of the key 2 moves upward while the rear end moves downward, and consequently the action unit 6 moves downward together with the rear end of the key 2. In this case, the back check 62 moves diagonally downward and backward, releasing the hammer 5 from its engagement with the back check 62 and freeing it from its stopped state. In addition, the repetition lever 52 has its front arm 72 pushed down by the biasing force of the repetition spring 54, thereby rotating counterclockwise around the repetition pivot shaft 63 as shown in Figure 13(a). Similarly, the jack 53 has its front arm 82 pushed down by the biasing force of the jack spring 55, thereby rotating counterclockwise around the jack pivot shaft 64 as shown in Figure 13(a). As a result, as shown in Figure 13(a), the upper end of the hammer thrust portion 83 of the jack 53 wraps around to the underside of the hammer projection portion 46 of the hammer 5, and consequently, the hammer 5 can be driven by the action unit 6 even if the key 2 has not completely returned to the unlocked position.

[0061] When key 2 is fully released, as shown in Figure 13(b), key 2, hammer 5, and the repetition lever 52 and jack 53 of the action unit 6 each return to their original released positions.

[0062] As described in detail above, according to this embodiment, the keyboard device 1 equipped with the aforementioned keys 2, action unit 6, and hammers 5 can achieve operation similar to that of a grand piano, thereby providing a touch and playability equivalent to that of a grand piano during performance.

[0063] Furthermore, in the hammer support 4 of the keyboard device 1, the contact surfaces 35a and 36a of the repetition stopper 35 and jack stopper 36, which the rear ends of the repetition lever 52 and jack 53 rear arm 84 of the action unit 6 contact when a key is pressed, are both inclined downwards towards the front. As a result, even if the holder 51 of the action unit 6 attached to the rear end of the key 2 is mounted misaligned in the front-to-back direction from the correct position during the manufacturing of the keyboard device 1, the rear ends of the repetition lever 52 and jack 53 rear arm 84 can contact the contact surfaces 35a and 36a of the repetition stopper 35 and jack stopper 36, respectively, at the appropriate timing. This allows for a good touch feel and appropriate sound production timing when pressing a key.

[0064] Furthermore, in the keyboard device 1, a guide groove 21a is formed at the rear end of the key 2, while a guide rib 60 is provided on the holder 51 of the action unit 6. Therefore, during the manufacturing of the keyboard device 1, the holder 51 is attached to the rear end of the key 2 with the guide rib 60 inserted into the guide groove 21a from the rear. As a result, the holder 51 is immobile in the left-right direction relative to the rear end of the key 2 by the left side wall 61d and the guide rib 60. Therefore, even when staples are driven into the holder 51 to attach it to the key 2 during the manufacturing of the keyboard device 1, the holder 51 attached to the key 2 will not be tilted in the left-right direction, and the holder 51 can be attached in the correct position. Consequently, since the holder 51 is attached in the correct position during the manufacturing of the keyboard device 1, the holder 54 does not come into contact with the hammer support 4 when the key is pressed, thereby providing stable key operation and good playing sound.

[0065] It should be noted that the present invention is not limited to the embodiments described above and can be implemented in various forms. Furthermore, the detailed configurations of the keyboard device 1, keys 2, hammer support 4, hammers 5, action unit 6, holder 51, repetition lever 52, and jack 53 shown in the embodiments are merely illustrative and can be modified as appropriate within the scope of the spirit of the present invention. [Explanation of Symbols]

[0066] 1 Keyboard device 2 keys 3-keyboard chassis 4 Hammer Support 5 Hammers 6 Action Units 21 Key body 33 Hammer support shaft 35 Repetition Stopper 35a Contact surface 36 Jack Stopper 36a Contact surface 51 Holder 52 Repetition Lever 53 Jack 73 Hammer mounting arm 73a Jack guide hole 83 Hammer thrust section 84 Rear arm

Claims

[Claim 1] A key that extends a predetermined length in the front-to-back direction and is pivotable with a pivot point near the center in the length direction, An action unit is provided at the rear of the key and performs a predetermined operation in conjunction with the pressing of the key, A hammer support positioned behind the aforementioned key, A hammer extends a predetermined length in the front-rear direction, is rotatably supported at its rear end via a hammer support shaft that extends in the left-right direction of the hammer support, and is mounted on the action unit via a hammer projection that protrudes downward immediately in front of the hammer support shaft, and is driven upward via the action unit when the key is pressed, Equipped with, The aforementioned action unit is A holder fixed to the rear end of the key, A repetition lever is formed in a predetermined shape extending in the front-rear direction and is rotatably mounted on the holder. The hammer projection is placed on the upper surface of the lever, which has a jack guide hole that penetrates in the vertical direction and extends in the front-rear direction. The repetition lever rises in response to the pressing of the key, thereby pushing up the hammer via the hammer projection and rotating it upward. The jack has a hammer thrusting portion extending vertically and a rear arm extending rearward from near the lower end of the hammer thrusting portion, is rotatably mounted on the holder, the upper end of the hammer thrusting portion is inserted from below into the jack guide hole of the repetition lever and engages with it so as to be movable in the front-rear direction, and the hammer thrusting portion thrusts the hammer upward via the hammer projection portion from the repetition lever as it rises in conjunction with the pressing of the key, causing the hammer to rotate upward. It is equipped with, The hammer support has a jack stopper that, while the hammer is being thrust upward by the jack, the rear end of the rear arm contacts it from below, thereby locking the jack in place and rotating the jack using the contacting rear end of the rear arm as a pivot point, thereby disengaging the hammer thrust portion of the jack from the hammer projection of the hammer. The jack stopper is inclined downwards toward the front and has a contact surface toward which the rear end of the rear arm can contact from below, characterized in that it is a keyboard device for a keyboard instrument.

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