Keyboard device for keyboard instrument

Abstract

To provide a keyboard device for a keyboard instrument, which, compared to a grand piano, reduces the number of components and adjustment points, thereby enabling improvement of productivity and maintainability and also obtainment of a favorable back check function.SOLUTION: A keyboard device for a keyboard instrument comprises: a key 2 that extends in a front-rear direction and freely swings; an action unit 6 that performs a predetermined operation in response to depression of the key 2; and a hammer 5 that is rotatably supported via a hammer support shaft 33 on a hammer support 4, and is driven upward via the action unit 6 as the key 2 is depressed. The hammer 5 includes a back check engagement part 47 that protrudes downward in front of the hammer support shaft 33. The key 2 is provided with a back check 62 that stops the hammer 5 by engagement of the back check engagement part 47 when the hammer 5 rebounds and rotates downward.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a keyboard device for a keyboard instrument, and more particularly to a keyboard device for a keyboard instrument having a back check function that prevents a hammer from rebounding when the hammer rotates in response to a key being pressed and returns to its original position. [Background technology]

[0002] Generally, acoustic grand pianos are provided with an action that operates when a key is pressed, rotating a hammer upward to strike the string. An example of such an action is disclosed, for example, in Patent Document 1, previously filed by the present applicant. This action is provided for each key and includes a wippen that is rotatably supported and placed at the rear of the key, a repetition lever and jack rotatably attached to the wippen, a repetition spring that biases these in a predetermined direction, a repetition screw and regulating button that respectively regulate the rotation of the repetition lever and jack, and a back check provided above the rear end of the key.

[0003] The hammer is made up of a hammer shank that extends in the front-to-rear direction and has a shank crawler attached to its base end, and a hammer head attached to its tip. The hammer is supported rotatably at the base end of the hammer shank.

[0004] In the above action, the repetition lever has a jack guide hole that penetrates vertically, and a hammer is placed near this jack guide hole via a shank roller. The jack has an L-shaped side profile, and the tip of the hammer thrust portion that extends vertically is inserted into the jack guide hole of the repetition lever from below, engages with it so that it can move back and forth, and faces the shank roller. The back check has a predetermined shape that extends vertically, and is attached to the top surface of the rear end of the key via a seat plate and a back check wire.

[0005] In a grand piano equipped with the hammer and action configured as described above, when a key is pressed, the wippen, which is thrust up at the rear of the key, rotates upward, causing the repetition lever and jack to move upward. As a result, the repetition lever first slides the shank roller, pushing the hammer upward and rotating it upward. Next, the repetition lever engages with the repetition screw and locks, causing the jack to thrust the hammer upward via the shank roller. Then, just before the hammer rotates to strike the string stretched above, the jack engages the regulating button and disengages from the shank roller (escapement). This escape of the jack releases the hammer from its connection with the action and key, allowing it to freely swing and strike the string. When the jack escapes, the touch weight (static load) of the key changes, specifically, a sudden increase in the touch weight followed immediately by a sudden decrease creates a clicking sensation, which gives the performer a so-called let-off feeling when playing the piano.

[0006] When the key is released and returned about one-third of its depth, the repetition lever begins to operate, and the spring force of the repetition spring causes it to rotate in the specified direction, pushing up the shank roller while sliding it. This causes the jack to rotate in the specified direction and return to its original position, allowing the next string to be struck even if the key has not yet returned completely to its released position.

[0007] The hammer, which rotates upward when the key is pressed, then rotates downward in reaction to the string being struck. Because the key is pressed, the back check at its rear end is positioned higher than when the key is released, and the tail of the hammer, specifically the tail located at the bottom of the hammer head, strikes the back check. The hammer, which makes contact with the back check, is then locked in place and stops without rebounding. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-31284 Summary of the Invention [Problem to be solved by the invention]

[0009] However, grand pianos have many components that make up their actions and hammers, and the rotating parts (hereinafter referred to as "rotating parts" in this section) and the parts that support them (hereinafter referred to as "support parts" in this section) are connected via pins. Specifically, the support parts have a bifurcated portion that supports the rotating parts, and the support parts are set inside the bifurcated portion. By inserting a pin into the connecting holes of both parts, the rotating parts are rotatably connected to the support parts. As such, grand pianos have many components that make up their actions and hammers, and the assembly process during manufacturing is complicated and time-consuming. Furthermore, in grand pianos, the rotation ranges of the various parts of the action and the hammers must be adjusted to operate properly, and this adjustment process is complicated.

[0010] Furthermore, because the back checks located above the rear ends of the keys are attached via back check wires inserted into the rear ends of the keys from above, there can be discrepancies in the position of the back checks for each key and variations in the height at which the hammers are engaged. To resolve these issues, adjustments such as bending the back check wires are required during the manufacture and maintenance of the grand piano, and these adjustments are cumbersome. Additionally, in a grand piano, the tails of the hammers are located behind the hammer pivots, which are the fulcrums for the hammers, and the back checks are attached to the rear ends of the keys, which increases the overall depth of the keyboard assembly. Therefore, it is difficult to achieve a compact design for keyboard instruments equipped with conventional keyboard assembly.

[0011] The present invention has been made to solve the above-mentioned problems, and aims to provide a keyboard device for a keyboard instrument that can improve productivity and maintainability by reducing the number of parts and adjustment points compared to a grand piano, and that can provide a good back check function.Furthermore, the depth dimension of the keyboard device can be reduced, allowing the entire instrument to be configured compactly. [Means for solving the problem]

[0012] In order to achieve the above object, the invention of claim 1 comprises a key that extends a predetermined length in the front-to-rear direction and is freely pivotable around a fulcrum located near the center of the length; an action unit that is provided at the rear of the key and performs a predetermined operation in conjunction with pressing the key; a hammer support that is provided at the rear of the key; and a hammer that extends a predetermined length in the front-to-rear direction and is rotatably supported at its rear end by a hammer spindle that extends in the left-to-right direction of the hammer support, and is driven upward via the action unit when the key is pressed, wherein the hammer has a back check engagement portion that protrudes downward forward of the hammer spindle, and the key is provided with a back check that stops the hammer when the hammer, which is driven upward when the key is pressed, rebounds and rotates downward by engaging the back check engagement portion.

[0013] According to this configuration, an action unit is provided at the rear of the key, and a hammer support is provided at the rear of the key. A hammer extending in the front-to-rear direction is rotatably supported at its rear end on the hammer support's hammer fulcrum. The hammer is provided with a back check engagement portion that protrudes downward and is forward of the hammer fulcrum, while the key is provided with a back check. When a key is pressed, the hammer is driven upward via the action unit, strikes a stopper, and rebounds, rotating downward, i.e., toward its original position. In this case, the hammer's back check engagement portion engages with the key's back check, stopping it. Thus, according to the present invention, the number of parts and adjustment points are reduced compared to a grand piano, thereby improving the productivity and maintainability of the keyboard device. Furthermore, the present invention appropriately prevents rebound when the hammer rebounds and rotates to its original position, thereby achieving an excellent back check function. Furthermore, in the present invention, the back check is located forward of the hammer spindle, so the depth dimension of the keyboard device can be made smaller than that of a grand piano keyboard device, in which the back check is located near the rear end of the key, allowing the entire instrument to be made compact.

[0014] The invention of claim 2 is characterized in that, in the keyboard device of the keyboard instrument described in claim 1, the hammer has a hammer body that extends a predetermined length in the front-to-rear direction and is made of synthetic resin, and the back check engagement portion is molded integrally with the hammer body.

[0015] With this configuration, the hammer has a hammer body made of synthetic resin that extends a predetermined length in the front-to-rear direction, and the back check engagement portion is molded integrally with the hammer body. Therefore, compared to the hammers of a grand piano, the number of parts can be reduced and manufacturing can be done with greater precision, thereby improving the productivity and maintainability of the keyboard device.

[0016] The invention of claim 3 is characterized in that, in the keyboard device of the keyboard instrument described in claim 2, the action unit is fixed to the key and has a holder made of synthetic resin, and the back check is molded integrally with the holder.

[0017] With this configuration, the action unit attached to the rear of the key has a holder made of synthetic resin, which is fixed to the key and the back check is molded integrally with it. This allows the back check to be precisely positioned on the key. This eliminates the need for back check adjustment, and makes maintenance easier than with back checks on grand pianos.

[0018] The invention of claim 4 is characterized in that, in the keyboard device of a keyboard instrument described in any one of claims 1 to 3, the back check is configured to lock the back check engagement portion while sliding it against the back check engagement portion when the back check engagement portion engages.

[0019] According to this configuration, when the back check engagement portion of the hammer engages with the back check of the key, the back check is configured to engage while sliding against the back check engagement portion, thereby reliably preventing the hammer from rebounding and rotating to its original position.

[0020] The invention of claim 5 is characterized in that, in the keyboard device of the keyboard instrument described in claim 4, a friction member for increasing friction is provided on at least one of the surfaces of the back check engagement portion and the back check that slide against each other.

[0021] According to this configuration, the friction member is provided on at least one of the surfaces of the back check engagement portion and the back check that slide against each other, so that when the back check engagement portion engages with the back check, the friction between the two can be used to appropriately stop the hammer at the desired position. [Brief explanation of the drawings]

[0022] [Figure 1] 1A and 1B are diagrams showing a part of a keyboard device of an electronic piano to which a keyboard device according to an embodiment of the present invention is applied, in which (a) is a perspective view and (b) is a right side view. [Figure 2] FIG. 1A is a perspective view showing an action unit attached to a key and a hammer placed on top of it, and FIG. 1B is a perspective view showing the key, action unit, and hammer disassembled. [Figure 3] 1A and 1B are perspective views showing a hammer support, in which FIG. 1A is an external view and FIG. 1B is a partially cutaway view. [Figure 4] 1A and 1B are diagrams showing a hammer support, in which (a) is a front view and (b) is a cross-sectional view taken along line AA. [Figure 5] 1A and 1B are enlarged perspective views showing the hammer and action unit, in which FIG. 1A shows the assembled parts of the action unit, and FIG. 1B shows the disassembled parts of the action unit. [Figure 6] FIG. 2(a) is a right side view of the hammer, and FIG. 2(b) is an enlarged perspective view of the hammer body before the roller bushing is attached. [Figure 7] FIG. [Figure 8] FIG. 4 is a right side view showing the repetition lever. [Figure 9] FIG. [Figure 10] 1A and 1B are explanatory diagrams sequentially illustrating the operation of the action unit and hammer when a key is pressed, in which (a) shows the key-release state, and (b) shows the state in which the repetition lever abuts against the repetition stopper when the key is pressed. [Figure 11] 10A and 10B are explanatory views showing a state in which the jack abuts against the jack stopper, and a state in which the jack has come out of the hammer protrusion. [Figure 12] 12A and 12B are explanatory views following FIG. 11, in which (a) shows the state in which the hammer abuts against the hammer stopper, and (b) shows the state in which the hammer bounces off the hammer stopper and abuts against the back check. [Figure 13]This is an explanatory diagram following Figure 12, in which (a) shows the state in which the depressed key is slightly released, causing the jack to move around below the hammer protrusion, and (b) shows the state in which the key has returned to its original released state. DETAILED DESCRIPTION OF THE INVENTION

[0023] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Figure 1 shows a part of a keyboard device of an electronic piano to which a keyboard device according to one embodiment of the present invention is applied, in a key-released state, with (a) being a perspective view and (b) being a right side view.

[0024] As shown in the figure, the keyboard device 1 comprises a number of keys 2 (only one white key is shown in Figure 1) lined up in the left-right direction of the electronic piano, a keyboard chassis 3 that supports these keys 2, hammer supports 4 connected to the rear end of the keyboard chassis 3, hammers 5 provided for each key 2 and rotatably supported by the hammer supports 4, action units 6 provided at the rear ends of the keys 2 that drive the hammers 5 upward when the keys are pressed, and key switches 7 for detecting key press information for the keys 2.

[0025] As shown in Figure 1, the keyboard chassis 3 is made up of three support rails 10, each extending left and right and consisting of a front rail 11, a middle rail 12, and a rear rail 13, which are spaced a predetermined distance apart in the front-to-rear direction (the left-to-right direction in Figure 1(b)), and a plurality of (e.g., five) reinforcing ribs 14 (only one is shown in Figure 1) which also extend front and back and are spaced a predetermined distance apart in the left-to-right direction. These support rails 10 and ribs 14 are made of steel plates formed into a predetermined shape by, for example, punching and bending with a press, and are connected to each other with screws.

[0026] The front rail 11 has a horizontal top panel 11a, a front panel 11b that bends downward at a right angle from the front end of the top panel 11a, and a bottom panel 11c that bends rearward at a right angle from the lower end of the front panel 11b. A reed front 15 is fixed to the underside of the top panel 11a by screws or the like. The reed front 15 is formed as a thick plate made of synthetic resin and extends in the left-right direction across the entire front rail 11. A number of front pins 16 are installed on the reed front 15 at front and rear positions corresponding to the white keys 2 and black keys (not shown), penetrating the top panel 11a of the front rail 11 and aligned in the left-right direction.

[0027] The middle rail 12 has a horizontal center reed mounting portion 12a, the front and rear ends of which are bent upward at right angles. A center reed 17 is mounted on the center reed mounting portion 12a and secured by screws or the like. The center reed 17 is formed into a thick plate made of synthetic resin and extends left and right across the entire middle rail 12. A number of balance pins 18 are arranged side by side on the center reed 17 at front and rear positions corresponding to the white keys 2 and black keys, respectively.

[0028] The rear rail 13 has an accommodation recess 13a that opens upward and engages with the lower part of the hammer support 4 while accommodating it, a cushion mounting portion 13b that bends at a right angle from the upper end of the front plate portion of the accommodation recess 13a and extends horizontally forward, and on which a cushion 19 extending in the left-right direction is mounted, and a connecting portion 13c that steps down one step from the front end of the cushion mounting portion 13b and further extends horizontally forward. The front plate portion of the accommodation recess 13a is formed with multiple mounting holes that penetrate in the front-to-rear direction, and the lower end of the hammer support 4 is screwed to the rear rail 13 through these mounting holes. The accommodation recess 13a and the connecting portion 13c are screwed to the rear end of each rib 14.

[0029] 2(a) shows the action unit 6 attached to the key 2 and the hammer 5 mounted thereon, while FIG. 2(b) shows the key 2, action unit 6, and hammer 5 in exploded view. As shown in the figure, the key 2 has a wooden key body 21 that extends a predetermined length in the front-to-rear direction and has a rectangular cross section, and a synthetic resin key cover 22 that is adhered to the upper and front surfaces 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 supported via this balance pin hole 23 so that it can swing freely on a balance pin 18 that is erected on a center reed 17.

[0030] The balance pin hole 23 is a substantially circular hole formed near the underside of the key body 21, with the entire upper part connected to the hole formed as an elongated hole extending in the length direction of the key body 21. Felt pads 23a are provided on the left and right inner surfaces of the balance pin hole 23 to allow the balance pin 18 to slide smoothly when the key 2 swings. A cushion 20 is attached to the top surface of the key body 21, behind the balance pin hole 23, and this cushion 20 prevents the front end of the hammer 5 from directly hitting the key 2 during maintenance, etc.

[0031] In addition, 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, and this front pin hole 24 engages with a front pin 16 that is erected on the front reed 15, thereby preventing the key 2 from wobbling left and right when it swings.

[0032] 3 and 4 show the hammer support 4. As shown in both figures, the hammer support 4 is made up of a molded part made of synthetic resin, and multiple molded parts, for example for one octave, 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 is made up of a hammer support section 31 that stands upright near the rear rail 13 and a switch mounting section 32 that extends diagonally upward from the upper end of the hammer support section 31. A hammer support shaft 33 is provided at the upper end of the hammer support section 31 to rotatably support each hammer 5.

[0033] The hammer support 4 has a plurality of partition walls 34 that separate adjacent hammers 5 at predetermined intervals in the left-right direction, and the hammer spindle 33 extends left-right between adjacent partition walls 34, 34. As shown enlarged in Figure 4(b), the hammer spindle 33 has an oval cross section with two notches cut out at the front and rear of a circle centered on the axis of the hammer spindle 33.

[0034] Specifically, the outer circumferential surface of the hammer spindle 33 is made up of a pair of upper and lower curved surfaces 33a, 33a and a pair of front and rear flat surfaces 33b, 33b extending between these curved surfaces 33a, 33a. In the hammer spindle 33 configured in this manner, the upper and lower curved surfaces 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 surfaces 33b, 33b is set to a length L2 that is shorter than the length L1.

[0035] 1, a key switch 7 is attached to the switch mounting portion 32 of the hammer support 4. The key switch 7 is composed of a switch board 7a made of a printed circuit board and a switch body 7b made of a rubber switch attached to each key 2 on the hammer 5 side of the switch board 7a.

[0036] 3 and 4, a repetition stopper 35 is provided on the rear side of the hammer support 4, diagonally rearward and below the hammer spindle 33, against which a repetition lever 52 (described later) of the action unit 6 abuts and locks when a key is pressed. Furthermore, a jack stopper 36 is provided on the rear side of the hammer support 4, below the repetition stopper 35, against which a jack 53 (described later) of the action unit 6 abuts and locks when a key is pressed. A cushion 37 extending in the left-right direction is attached to the underside of the jack stopper 36.

[0037] As shown in FIG. 1, a hammer stopper 38 is provided at the upper front end of the hammer support 4, which contacts the hammer 5 from below when the hammer 5 rotates upward, preventing further rotation.

[0038] Fig. 5 shows the hammer 5 and action unit 6, with (a) showing the assembled parts of the action unit and (b) showing the disassembled parts of the action unit. Also, Fig. 6(a) is 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-to-rear direction, and two weight plates 42, 42 attached to the front ends of the left and right sides of the hammer body 41. The hammer body 41 is made of synthetic resin, and the weight plate 42 is made of a metal material such as iron that has a relatively high specific gravity.

[0039] The rear end of the hammer body 41 is provided with an engagement portion 43 that engages with the hammer spindle 33 of the hammer support 4. This engagement portion 43 is formed with an arc-shaped shaft hole 44 that penetrates in the left-right direction and has a C-shaped side surface, with the opening widening outward. The shaft hole 44 has a diameter slightly larger than the diameter (length L1) of the upper and lower curved surfaces 33a, 33a of the hammer spindle 33, and the width L3 of the opening is slightly larger than the length L2 between the front and rear flat surfaces 33b, 33b of the hammer spindle 33 but smaller than the length L1. The hammer 5 is detachably attached to the hammer spindle 33 of the hammer support 4 via the opening of the shaft hole 44. The hammer 5 is rotatably supported by the hammer support 4 by fitting the shaft hole 44 onto the hammer spindle 33.

[0040] Additionally, a switch pressing portion 45 and a hammer protruding portion 46 are provided at the rear of the hammer 5, respectively, above and below the shaft hole 44, just in front of the shaft hole 44. The switch pressing portion 45 has a flat upper surface, and when the hammer 5 rotates upward, it presses the switch body 7b of the key switch 7, thereby detecting key depression information for the key 2 corresponding to the hammer 5.

[0041] On the other hand, the hammer protrusion 46 corresponds to the shank roller of a grand piano hammer. Figure 6(b) shows an enlarged view of the hammer body 41 before the roller bushing 49 is attached. As shown in the figure, the hammer protrusion 46 is molded integrally with the hammer body 41 and has a protrusion body 48 that protrudes downward, and a roller bushing 49 that is attached to the hammer body 41 and covers the protrusion body 48.

[0042] The protrusion body 48 protrudes downward, and the side surface of the tip is formed in an arc shape. The protrusion body 48 is formed symmetrically, and each side surface (the right side surface is shown in FIG. 6(b)) is provided with a groove 48a that extends in the vertical direction and opens outward, and a locking recess 48b provided at the upper end of the groove 48a.

[0043] On the other hand, the roller bushing 49 is made of a predetermined elastic material (e.g., thermoplastic elastomer) and is a molded product having a predetermined shape. Specifically, as shown in FIG. 6(b), the bushing 49 has an upwardly opening, a bushing body 49a formed so that the protrusion body 48 of the hammer body 41 can be fitted therein and attached to the protrusion body 48, and two left and right hooks 49b, 49b protruding upward from the bushing body 49a and spaced a predetermined distance apart in the left-right direction. The bushing body 49a has a side surface that curves downwardly convexly and has a predetermined curvature, for example, approximately the same curvature as the shank roller of a grand piano. Furthermore, the upper end of each hook 49b is formed like a claw that protrudes inward.

[0044] In the hammer protrusion 46 configured as described above, the roller bushing 49 is attached to the hammer body 41 with the protrusion body 48 of the hammer body 41 fitted into the bushing body 49a of the roller bushing 49 and with both hooks 49b, 49b of the roller bushing 49 fitted into the corresponding left and right grooves 48a and locking recesses 48b of the protrusion body 48. In this case, the upper ends of the hooks 49b of the roller bushing 49 are locked in the locking recesses 48b of the protrusion body 48 in a manner that prevents them from coming off.

[0045] In the key-released state, the hammer protruding portion 46 is placed on a hammer placing portion 74 of a repetition lever 52 of the action unit 6, which will be described later.

[0046] 5 and 6(a), a back check engaging portion 47 is provided at a predetermined position on the front of the hammer 5. The back check engaging portion 47 is molded integrally with the hammer body 41, protrudes downward, and is engageable with a back check 62 (described later) of the action unit 6. As shown in FIG. 6(a), the back check engaging portion 47 has a vertically elongated side shape, with the front surface formed flat and the back surface formed with a gentle curve.

[0047] Next, we will explain the action unit 6. As shown in Figure 5, the action unit 6 includes a holder 51 fixed to the rear end of the key 2, a repetition lever 52 and a jack 53 rotatably attached to the holder 51, and a repetition spring 54 and a jack spring 55, both of which are coil springs, that urge the holder 51 and jack 53 to rotate in predetermined directions.

[0048] Figure 7 shows a right side view of holder 51. As shown in Figure 7 and Figure 5, holder 51 is made of synthetic resin and is a molded product of a predetermined shape formed to extend in the front-to-rear direction. This holder 51 has a key mounting part 61 located at the front and fixed to the rear end of key 2, a back check 62 located above it, a repetition spindle 63 located at the upper end near the center in the front-to-rear direction and rotatably supporting repetition lever 52, and a jack spindle 64 located at the rear end and rotatably supporting jack 53.

[0049] The key mounting portion 61 has a U-shaped side surface formed by an upper wall 61a, a rear wall 61b, and a lower wall 61c, and the left ends of these walls are joined by a left wall 61d. Therefore, when the holder 51 is attached to the rear end of the key 2, the upper wall 61a, the rear wall 61b, the lower wall 61c, and the left wall 61d are firmly fixed by adhesive in contact with the upper, rear, lower, and left sides of the rear end of the key 2.

[0050] 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, when the back check engaging portion 47 of the hammer 5 engages with the back check 62, the back check 62 is configured to engage the back check engaging portion 47 while sliding against the back check engaging portion 47. Note that a friction member such as synthetic leather may be attached to at least one of the surfaces of the back check 62 and the back check engaging portion 47 that come into sliding contact with each other in order to increase friction.

[0051] The repetition support shaft 63 and the jack support shaft 64 are both formed in a cylindrical shape with a predetermined diameter and protruding to the right by a predetermined length. The repetition support shaft 63 is formed at a predetermined position higher than the jack support shaft 64.

[0052] Furthermore, holder 51 is provided with a repetition spring locking portion 65, which locks the upper end of repetition spring 54, between back check 62 and repetition spindle 63, at a predetermined position in front of repetition spindle 63. Furthermore, holder 51 is provided with a jack spring locking portion 66, which locks the upper end of jack spring 55, between repetition spindle 63 and jack spindle 64, at a predetermined position in front of jack spindle 64. Furthermore, holder 51 is provided with a protrusion 67, which protrudes slightly downward, on the rear underside, and holder 51 rests on cushion 19 on rear rail 13 via protrusion 67 in the key-released state.

[0053] Figure 8 shows a right side view of the repetition lever 52. As shown in Figure 8 and Figure 5, the repetition lever 52 is made of synthetic resin and is a molded product of a predetermined shape formed to extend in the front-to-rear direction. The repetition lever 52 has a fitting hole 71 that penetrates in the left-to-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 extends rearward from near the fitting hole 71, on which the hammer 5 is placed and with which the jack 53 engages.

[0054] The hammer mounting arm 73 of the repetition lever 52 has a hammer mounting portion 74 whose side shape extends obliquely upward and rearward by a predetermined distance from the fitting hole 71, and an extension portion 75 that extends obliquely downward and rearward from the rear end of the hammer mounting portion 74 and further rearward. The hammer mounting arm 73 also has a jack guide hole 73a that penetrates vertically and extends in the front-rear direction between the hammer mounting portion 74 and the extension portion 75. The rear end of the extension portion 75 is formed to protrude slightly upward, and a cushion 76 is attached to its upper surface.

[0055] Figure 9 shows a right side view of the jack 53. As shown in Figure 9 and Figure 5, the jack 53 is made of synthetic resin and is 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 spindle 64 of the holder 51, a front arm 82 that extends forward from near the fitting hole 81, a hammer thrust portion 83 that extends upward a predetermined length from near the fitting hole 81, and a rear arm 84 that extends rearward from near the fitting hole 81.

[0056] The hammer thrust-up portion 83 extends diagonally upward and forward at a predetermined angle relative to the front arm 82 and rear arm 84, which extend substantially horizontally in the front-to-rear direction. The upper end of the hammer thrust-up portion 83 is formed to be narrower in the front-to-rear direction than the portion below it. The rear end of the rear arm 84 is formed so that it protrudes slightly upward.

[0057] Furthermore, in the jack 53, plate-shaped reinforcing ribs 85a, 85b, and 85c are provided between the front arm 82 and the hammer thrust portion 83, between the hammer thrust portion 83 and the rear arm 84, and between the rear arm 84 and the front arm 82. These reinforcing ribs 85a to 85c and the like increase the strength of the jack 53.

[0058] In the action unit 6 formed as described above, as shown in FIG. 5(a), the hammer thrust portion 83 of the jack 53 is inserted into the jack guide hole 73a of the repetition lever 52 from below and engaged therewith. Also, as shown in the same figure, the front arm 72 of the repetition lever 52 is urged downward by the repetition spring 54, while the front arm 82 of the jack 53 is urged downward by the jack spring 55. As a result, the repetition lever 52 and the jack 53 are urged counterclockwise in FIG. 5(a) about the repetition spindle 63 and the jack spindle 64, respectively. Note that thin plate-shaped cushions 91 and 92 are attached to the holder 51 of the action unit 6 on the underside of the front arm 72 of the repetition lever 52 and the underside of the front arm 82 of the jack 53.

[0059] Next, the operation of the action unit 6 and the hammer 5 when the key 2 is depressed will be described with reference to FIGS.

[0060] 10(a) shows the keyboard device 1 in the released state. In this released state, the hammer 5 is placed on the hammer placement portion 74 of the repetition lever 52 via the hammer protrusion 46, and the upper end of the hammer thrust portion 83 of the jack 53 faces the hammer protrusion 46 with a gap between them. Also, in the released state, a gap is provided between the back check engagement portion 47 of the hammer 5 and the back check 62 of the holder 51.

[0061] When the front end of the key 2 is pressed down from the above-mentioned key-released state, the key 2 swings downward around the balance pin 18, and the rear end of the key 2 moves upward. Accordingly, the action unit 6 also moves upward together with the rear end of the key 2, and the hammer 5 is pushed up by the repetition lever 52 via the hammer protrusion 46. This causes the hammer 5 to rotate upward (clockwise in FIG. 10 ) around the hammer support shaft 33.

[0062] Next, as the key is pressed further and the action unit 6 moves upward, the rear end of the repetition lever 52 abuts against the repetition stopper 35 of the hammer support 4 from below via the cushion 76, as shown in Figure 10(b). As a result, the rear end of the repetition lever 52 becomes locked, while the upper end of the hammer thrust-up portion 83 of the jack 53 abuts against the hammer protrusion 46 from below. As a result, the hammer 5 is thrust up by the hammer thrust-up portion 83 of the jack 53 and rotates further upward.

[0063] Next, as the key is further depressed and the action unit 6 moves further upward, the rear end of the rear arm 84 of the jack 53 abuts against the jack stopper 36 (cushion 37) from below, as shown in FIG. 11(a). As a result, with the rear end of the rear arm 84 locked, the jack 53 rotates clockwise around the jack spindle 64 as shown in FIG. 11(a) as the jack spindle 64 moves upward. As a result, as shown in FIG. 11(b), the upper end of the hammer thrust portion 83 of the jack 53 moves rearward and disengages from the hammer protrusion 46 of the hammer 5. With this escape of the jack 53, the hammer 5 is released from the connection with the action unit 6 and the key 2 and rotates further upward in a freely rotating state.

[0064] When the jack 53 escapes, a clicking sensation occurs due to a sudden increase or decrease in the touch weight of the key 2, which gives the player a let-off feeling when pressing the key.

[0065] 12(a) shows a state in which the hammer 5, having rotated upward, abuts against the hammer stopper 38 at the upper front end of the hammer support 4. In this case, the front portion of the hammer body 41 of the hammer 5 abuts against the hammer stopper 38 from below, preventing the hammer 5 from rotating any further. In this case, the switch pressing portion 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 depression information for the key 2 according to the rotation speed of the hammer 5, etc., and outputs it to a sound generation control device (not shown). The sound generation control device then outputs piano sounds from the electronic piano's speaker (not shown) based on the key depression information.

[0066] FIG. 12(b) shows the state immediately after the hammer 5 contacts the hammer stopper 38. Specifically, the hammer 5 bounces off the hammer stopper 38 and rotates downward (counterclockwise) toward its original position before the key was pressed, with the back check engagement portion 47 of the hammer 5 locked in the back check 62 of the holder 51. In this case, the back check engagement portion 47 is locked in sliding contact with the back check 62, preventing the hammer 5 from rotating further downward and stopping, thereby preventing rebound and vibration of the hammer 5. In this case, the load caused by the rebound of the hammer 5 is transmitted to the key 2. As a result, the player can clearly feel the key 2 stop when the key 2 is fully depressed.

[0067] FIG. 13(a) shows the state in which the depressed key 2 is slightly returned (e.g., 1 / 3 of the keyboard depth) upon key release. When the key is released from the state shown in FIG. 12(b), as shown in FIG. 13(a), the front end of the key 2 moves upward while the rear end moves downward. Accordingly, 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 rearward, disengaging the hammer 5 from the back check 62 and releasing it from its stopped state. Additionally, the repetition lever 52 has its front arm 72 pressed downward by the biasing force of the repetition spring 54, causing it to rotate counterclockwise in FIG. 13(a) around the repetition spindle 63. Similarly, the jack 53 has its front arm 82 pressed downward by the biasing force of the jack spring 55, causing it to rotate counterclockwise in FIG. 13(a) around the jack spindle 64. 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 protrusion portion 46 of the hammer 5, and as a result, the hammer 5 can be driven by the action unit 6 even if the key 2 does not fully return to the released position.

[0068] When the key 2 is completely released, the key 2, hammer 5, and repetition lever 52 and jack 53 of the action unit 6 each return to their original released positions, as shown in FIG. 13(b).

[0069] As described above in detail, according to this embodiment, the keyboard device 1 equipped with the above-described keys 2, action unit 6, and hammers 5 can achieve the same operation as a grand piano, thereby providing the same touch and playability as a grand piano when playing. Furthermore, the action unit 6 of the keyboard device 1 can reduce the number of parts and the number of adjustment points compared to the action of a grand piano, thereby improving the productivity and maintainability of the keyboard device 1.

[0070] Furthermore, in the keyboard device 1, when the hammer 5 rotates to its original position following the release of the key 2, the back check engagement portion 47 of the hammer 5 is engaged with the back check 62 of the action unit 6, thereby appropriately preventing rebound of the hammer 5 and achieving a good back check function.

[0071] Furthermore, in the keyboard device 1, the back check engagement portion 47 and the back check 62 are located forward of the hammer support shaft 33, so the depth dimension of the keyboard device 1 can be made smaller than that of a grand piano keyboard device, in which the back check is located near the rear end of the key, allowing the entire electronic piano to be configured compactly.

[0072] The present invention is not limited to the above-described embodiment, but can be embodied in various forms. For example, in the embodiment, the present invention is described as being applied to a keyboard device of an electronic piano, but the present invention is not limited to this. Instead of key switches 7, strings similar to those of a grand piano can be stretched above the hammers 5, and the strings can be struck by the hammers 5.

[0073] In addition, in the embodiment, the back check 62 is integrally formed with the holder 51, but the present invention is not limited to this, and a back check of a predetermined shape can also be attached directly to the key 2.

[0074] Furthermore, the detailed configurations of the keyboard device 1, the keys 2, the hammers 5, and the action unit 6 shown in the embodiment are merely examples, and can be modified as appropriate within the scope of the present invention. [Explanation of symbols]

[0075] 1 Keyboard device 2 keys 3-key chassis 4 Hammer Support 5 Hammer 6 Action Unit 7 Key Switch 33 Hammer spindle 41 Hammer body 42 Weight plate 47 Back check engagement part 51 Holder 52 Repetition Lever 53 Jack 62 Back Check

Claims

1. a key that extends a predetermined length in the front-rear direction and is pivotable around a fulcrum located near the center of the length; an action unit provided at the rear of the key and configured to execute a predetermined action in response to depression of the key; The hammer support provided on the rear side of this key, a hammer extending a predetermined length in the front-rear direction, rotatably supported at its rear end by a hammer support shaft extending in the left-right direction of the hammer support, and driven upward via the action unit when the key is pressed; Equipped with The hammer has a back check engagement portion that protrudes downward and is located forward of the hammer spindle, a back check engaging portion that engages with the hammer when the hammer is driven upward as the key is pressed and then rotates downward, thereby stopping the hammer;

2. The hammer has a hammer body that extends a predetermined length in the front-rear direction and is made of synthetic resin, 2. The keyboard device for a keyboard instrument according to claim 1, wherein the back check engaging portion is molded integrally with the hammer body.

3. The action unit has a holder made of synthetic resin and is fixed to the key, 3. The keyboard device for a keyboard instrument according to claim 2, wherein the back check is molded integrally with the holder.

4. 4. The keyboard device for a keyboard instrument according to claim 1, wherein the back check is configured to lock the back check engagement portion while sliding against the back check engagement portion when the back check is engaged.

5. 5. The keyboard device for a keyboard instrument according to claim 4, wherein a friction member for increasing friction is provided on at least one of the surfaces of said back check engagement portion and said back check that slide against each other.

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