Keyboard mechanism of a keyboard instrument

Abstract

This invention provides a keyboard mechanism for a keyboard instrument that allows the holder of the action unit, which is attached to the rear end of the key, to be mounted in the correct position during the manufacturing of the keyboard mechanism, thereby achieving stable key operation and good playing sound when the key is pressed. [Solution] The keyboard device 1 comprises a pivotable 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 key has a guide groove 21a at its rear end that extends in the front-rear direction and opens to the rear. The holder 51 of the action unit, which is fixed to the rear end of the key, has a left side wall 61d that is adhered to the left side of the key, an upper wall 61a that is adhered to the upper surface of the key, a rear wall 61b that is located behind the rear surface of the key, and a guide rib 60 that extends forward from the rear wall and is inserted into the guide groove.

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 previously filed by the present 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, and an action unit that executes a predetermined operation in conjunction with the key depression is attached to the rear portion 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.

[0003] [[ID=1's]] The holder of the action unit is composed of a molded product made of synthetic resin, and has a key attachment portion fixed to the rear end portion of the key at the front portion. This key attachment portion is formed in a U-shaped side surface shape by an upper wall, a rear wall, and a lower wall, and these left end portions are formed so as to be continuous with a left side wall. When attaching the holder formed as described above to the rear end portion of the key during the manufacture of the keyboard device, an adhesive is applied to the left side surface and the upper surface of the key, and the key attachment portion of the holder is adhered to the key in a state where the entire left side wall thereof is in close contact with the left side surface of the key. Also, in this case, in order to fix the holder more firmly to the key, staples are driven into the rear end portion of the key from above the upper wall of the key attachment portion of the holder.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, as described above, when staples are driven into the key mounting portion of the holder, vibrations during this process may cause the key mounting portion of the holder to be attached to the key in a tilted position in the left-right direction in a plan view, rather than in the correct orientation along the length of the key. For example, if the rear of the left wall of the key mounting portion of the holder is lifted away from the left side of the rear end of the key, the holder will tilt to the left in a plan view, and the deviation from the correct position will be particularly large in the rear part of the holder. If such a large deviation occurs in a holder attached to the rear end of a key, the holder, which moves up and down in conjunction with the key's operation when pressed, may come into contact with the hammer support. In that case, the key's operation may be hindered, noise may be generated, and stable key operation and a good playing sound may not be obtained when the key is pressed.

[0006] The present invention was made to solve the above-mentioned problems, and aims to provide a keyboard device for a keyboard instrument in which the holder of the action unit attached to the rear end of the key can be attached in the correct position during the manufacturing of the keyboard device, thereby enabling stable key operation and good playing sound when the key is pressed. [Means for solving the problem]

[0007] To achieve the above objective, the invention according to claim 1 comprises a key that extends a predetermined length in the front-rear direction and is 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; a hammer that extends a predetermined length in the front-rear direction and is rotatably supported at its rear end via a hammer support shaft extending in the left-right direction of the hammer support, and is mounted on the action unit via a hammer projection provided so as to protrude downward immediately in front of the hammer support shaft, and is driven upward via the action unit in conjunction with the pressing of the key, wherein a guide groove extending in the front-rear direction and opening to the rear is formed at the rear end of the key, the action unit comprises a holder fixed to the rear end of the key, the holder having a side wall adhered to one side in the left-right direction of the rear end of the key, an upper wall adhered to the upper surface of the rear end of the key, a rear wall located on the rear side of the rear surface of the rear end of the key, and a guide rib extending forward from the rear wall and inserted into the guide groove.

[0008] 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. When the front end of the key is pushed down during keying, the rear end of the key moves upward together with the holder of the action unit, and as a result, the action unit performs a predetermined operation, driving the hammer upward.

[0009] A guide groove is formed at the rear end of the key, extending in the front-to-back direction and opening to the rear. The holder of the action unit, which is fixed to the rear end of the key, has the aforementioned side wall, top wall, rear wall, and guide rib. When attaching the action unit holder to the rear end of the key during the manufacturing of the keyboard device, the side wall and top wall of the holder are bonded to the side and top surfaces of the rear end of the key, respectively. The rear wall of the holder is positioned behind the rear surface of the rear end of the key, and the guide rib of the holder is inserted into the guide groove of the rear end of the key. By attaching the holder to the rear end of the key in this manner, the holder becomes immobile in the left-to-right direction relative to the rear end of the key due to its side wall and guide rib. Therefore, even when attaching the holder to the key by driving staples into it during the manufacturing of the keyboard device, as in the conventional method, the holder attached to the key will not be installed at an angle in the left-to-right direction, and the holder can be installed in the correct orientation. Therefore, according to the present invention, when manufacturing the keyboard device, the holder of the action unit attached to the rear end of the key can be mounted in the correct position, thereby enabling stable key operation and good playing sound when the key is pressed.

[0010] The invention according to claim 2 is a keyboard device for a keyboard instrument described in claim 1, characterized in that the guide groove is formed to penetrate vertically at the rear end of the key.

[0011] With this configuration, the guide groove provided at the rear end of the key is formed to penetrate vertically, making it relatively easy to form a guide groove that penetrates vertically compared to forming a hole-shaped guide groove that opens to the rear at the rear end of the key.

[0012] The invention according to claim 3 is a keyboard device for a keyboard instrument described in claim 1 or 2, characterized in that the guide ribs are formed in a flat plate shape having a predetermined thickness.

[0013] With this configuration, since the guide ribs are formed in a flat shape, the holder is attached to the rear end of the key by firmly gripping a portion of the key's rear end from both sides between the guide ribs and the side walls of the holder. As a result, even when stapling into the holder, the holder does not tilt from side to side, and the holder can be firmly fixed in the correct position on the rear end of 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, with (a) being a perspective view and (b) being 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] This is a right side view of the hammer. [Figure 7] This is a right side view showing the holder. [Figure 8] (a) is a right side view showing the repetition lever, and (b) is a right side view showing a modified repetition lever. [Figure 9] (a) is a right side view of Jack, and (b) is a right side view of a modified version of Jack. [Figure 10]This is an explanatory diagram for sequentially explaining the operations of the action unit and the hammer when the key is pressed. (a) shows the key-released state, and (b) shows the state where the repetition lever abuts against the repetition stopper when the key is pressed. [Figure 11] This 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 of the hammer projection. [Figure 12] This 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] This is an explanatory diagram following FIG. 12. (a) shows the state where the pushed key is slightly retracted and the jack has rotated under the hammer projection, and (b) shows the state where the key has returned to the original key-released state.

Best 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 number of keys 2 arranged in the left-right direction of the 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 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 of the key 2 that drives the hammer 5 upward as the key is pressed, a key switch 7 for detecting the 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, 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 such as 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 the top plate portion 11a, and a bottom plate portion 11c that bends backward at a right angle from the lower end portion of the front plate portion 11b. On the lower surface of the top plate portion 11a, a front rail cover 15 is fixed by screwing or the like. The front rail cover 15 is formed into a thick plate shape made of synthetic resin and extends in the left - right direction over the entire front rail 11. A number of front pins 16 are erected at the 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 middle rail 12 has a horizontal middle rail mounting portion 12a, and its front end portion and rear end portion are bent upward at a right angle. The middle rail 17 is fixed by screwing or the like in a state of being placed on the above - mentioned middle rail mounting portion 12a. The middle rail 17 is formed into a thick plate shape made of synthetic resin and extends in the left - right direction over the entire middle rail 12. A number of balance pins 18 are erected at the front - rear positions corresponding to the white keys 2 and black keys in a state of being arranged in the left - right direction.

[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 21a Guide groove 33 Hammer shaft 51 Holder 52 Repetition Lever 53 Jack 60 Guide Ribs 61 Key mounting section 61a Upper wall of the key mounting section 61b Rear wall of the lock mounting section 61c Lower wall of the lock mounting section 61d Left side wall of the key mounting area

Claims

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 rear end of the key has a guide groove that extends in the front-rear direction and opens to the rear. The action unit includes a holder fixed to the rear end of the key, The holder in question is, A side wall is bonded to one side in the left-right direction at the rear end of the key, An upper wall that is adhered to the upper surface of the rear end of the key, The rear wall located on the rear side of the rear end of the key, A guide rib extending forward from the rear wall and inserted into the guide groove, A keyboard device for a keyboard instrument, characterized by having the following features.

2. The keyboard device for a keyboard instrument according to claim 1, characterized in that the guide groove is formed to penetrate vertically at the rear end of the key.

3. The keyboard device for a keyboard instrument according to claim 1 or 2, characterized in that the guide rib is formed in the shape of a flat plate having a predetermined thickness.

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