This application claims priority to Japanese Patent Application Number 2020-153438, filed on Sep. 14, 2020, the entire content of which is incorporated herein by reference.
The present invention relates to a keyboard device for a keyboard instrument including a hammer which is applied to a keyboard instrument, such as an electronic piano, and is configured to be pivotally moved in accordance with depression of a key.
Conventionally, as this kind of a keyboard device for a keyboard instrument, there has been known, for example, one disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2009-75404. In this keyboard device, a key frame as a keyboard chassis is disposed on a key frame bottom board as a keybed. Keys are arranged on an upper side of the key frame, and mass bodies as hammers are arranged inside the key frame. The keys extend in a front-rear direction, and has rear ends thereof pivotally supported on a rear end of an upper surface of the key frame. On the other hand, the mass bodies extend in the front-rear direction and each have an arm having a front portion pivotally supported by the key frame and a main body as a weight mounted to a rear end of the arm. Further, at a predetermined location of the key frame bottom board, there is provided a lower limit stopper for restricting lower limit positions of the mass bodies which vertically pivotally move.
In the above-described keyboard device, when a front end of a key is pressed down for key depression, a front end of an arm of an associated mass body is depressed, accordingly. With this, the mass body is pivotally moved such that the main body at the rear end of the mass body is moved upward, whereby the mass body reaches an upper limit position. Then, when the finger is released from the key being depressed, for key release, the depression of the front end of the arm is released, whereby the mass body pivotally moves such that the main body positioned at the upper limit position moves downward. As a consequence, the main body or the rear end of the arm contacts the lower limit stopper from above, whereby further pivotal motion of the mass body is blocked.
As described above, in the conventional keyboard device, during key release immediately after key depression, a portion of the mass body relatively far away from a pivot thereof, more specifically, the main body of the mass body or the rear end of the arm moves into contact with the lower limit stopper from above. In this case, a height of the main body at the start of the downward movement thereof, that is, a distance between the main body located at the upper limit position and the lower limit stopper is relatively large, and hence the speed of the main body and the impact thereof on the lower limit stopper when the main body or the like moves into contact with the lower limit stopper are large, so that noise is liable to be generated by the contact. Further, since the lower limit stopper is mounted on the key frame bottom board as the keybed, when the main body or the like moves into contact with the lower limit stopper, vibration and noise generated by the contact are directly transmitted to the key frame bottom board, and more widely spread to surroundings via the key frame bottom.
It is an object of the present invention to provide a keyboard device for a keyboard instrument, which is capable of largely reducing noise generated when a hammer contacts a lower limit stopper during key release immediately after key depression.
To attain the above object, the present invention provides a keyboard device for a keyboard instrument, including a keybed, a keyboard chassis disposed on the keybed, a plurality of keys each extending in a front-rear direction and pivotally supported on the keyboard chassis, the keys being arranged side by side in a left-right direction, a plurality of hammers each extending in the front-rear direction and pivotally supported on the keyboard chassis below the plurality of keys, the hammers being arranged side by side in the left-right direction and being vertically pivotally moved in accordance with depression of associated ones of the keys, respectively, an extension rail extending below a rotational shaft of the plurality of hammers and its vicinity along an entirety of the plurality of hammers in the left-right direction, the extension rail being mounted on the keyboard chassis in a state floating from the keybed, and a lower limit stopper which is mounted on the extension rail and on which each of the plurality of hammers is placed via a predetermined placement-contact portion thereof when in a key-released state, the lower limit stopper blocking further pivotal motion of the hammer by having the hammer contact itself from above when the hammer pivotally moved upward by key depression pivotally moves downward in accordance with key release.
With this construction, the plurality of keys each extending in the front-rear direction and the plurality of hammers disposed below the plurality of keys are pivotally supported on the keyboard chassis mounted on the keybed and are arranged side by side in the left-right direction. The hammers are vertically pivotally moved in accordance with depression of associated ones of the keys, respectively. Further, the extension rail, which extends below the rotational shaft of the plurality of hammers and its vicinity along the entirety of the hammers in the left-right direction, is mounted on the keyboard chassis in the state floating from the keybed. Furthermore, the lower limit stopper is mounted on the extension rail. Each hammer is placed on the lower limit stopper via the predetermined placement-contact portion thereof when in the key-released state. Further, when the hammer pivotally moved upward by key depression pivotally moves downward in accordance with key release, the lower limit stopper has the placement-contact portion of the hammer contact itself from above.
The above-described lower limit stopper is mounted on the extension rail, and hence differently from the conventional keyboard device in which a portion far away from a rotational shaft of a hammer moves into contact with a lower limit stopper, the placement-contact portion of the hammer moves into contact with the lower limit stopper disposed at a location relatively close to the rotational shaft of the hammer. With this, when the hammer starts to pivotally move downward at the time of key release immediately after key depression, a distance between the placement-contact portion and the lower limit stopper is relatively short, which reduces the speed of the placement-contact portion of the hammer and the impact thereof on the lower limit stopper when the placement-contact portion of the hammer moves into contact with the lower limit stopper. As a result, compared with the conventional keyboard device, it is possible to reduce noise generated by the contact. Further, the extension rail having the lower limit stopper mounted thereon is mounted on the keyboard chassis in the state floating from the keybed, so that when the hammer pivotally moves downward into contact with the lower limit stopper, vibration and noise generated by the contact cannot be directly transmitted to the keybed. As described above, the lower limit stopper with which the hammer moves into contact is disposed below the rotational shaft of the hammer and its vicinity and is also mounted on the extension rail in the state floating from the keybed, whereby compared with the conventional keyboard device, it is possible to largely reduce noise generated when the hammer contacts the lower limit stopper.
Preferably, the lower limit stopper extends along a longitudinal direction of the extension rail and is disposed along the entirety of the plurality of hammers.
With the construction of this preferred embodiment, since the lower limit stopper of the extension rail extends along the longitudinal direction of the extension rail, and is disposed along the entirety of the plurality of hammers, it is possible to easily form the lower limit stopper associated with all the hammers, by a single member. Further, compared with a case where during manufacturing of a keyboard device, an individual lower limit stopper is mounted on an extension rail on a hammer-by-hammer basis, it is possible to improve manufacturing efficiency.
Preferably, each of the plurality of hammers has a predetermined length from the rotational shaft to a rear end thereof, and the lower limit stopper is disposed on the extension rail such that the placement-contact portion of the hammer is located closer to the rotational shaft than a location corresponding to half of the predetermined length is.
With the construction of this preferred embodiment, the lower limit stopper is disposed on the extension rail such that the placement-contact portion of the hammer having the predetermined length from the rotational shaft to the rear end thereof is located closer to the rotational shaft than the location corresponding to half of the predetermined length (hereinafter referred to as “the center position” in this section) is. As described above, the placement-contact portion, which is located closer to the rotational shaft than the center position of the hammer is, moves into contact with the lower limit stopper, and hence compared with e.g. a case where a portion of the hammer, which is located closer to the rear end than the center position of the hammer is, moves into contact with the lower limit stopper, it is possible to positively reduce the distance between the placement-contact portion and the lower limit stopper at the start of the downward pivotal motion of the hammer. With this, it is possible to reduce the speed of the hammer and the impact thereof on the lower limit stopper when the hammer moves into contact with the lower limit stopper to thereby ensure reduction of noise.
Preferably, the lower limit stopper is formed of an elastic material.
With the construction of this preferred embodiment, since the lower limit stopper is formed of an elastic material, it is possible to reduce the impact of the hammer when the hammer contacts the lower limit stopper to thereby further reduce noise generated by the contact.
The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.
The present invention will now be described in detail with reference to the drawings showing preferred embodiments thereof.
The keyboard chassis 2 is formed by a plurality of molded articles arranged in parallel with each other in a left-right direction (in a depth direction as viewed in
The chassis front 11 has a plurality of pairs of engagement holes 21 provided for each associated one of the white keys 3, each pair being formed by two engagement holes 21 left and right (only one of which is shown in
The chassis intermediate portion 12 has a pivot shaft 12a (rotational shaft) extending in the left-right direction, and the hammers 6 are pivotally supported on the pivot shaft 12a. Further, key switches 27 extending toward the chassis front 11 are mounted on the chassis intermediate portion 12, for each detecting key depression information on an associated one of the keys 5. The key switches 27 are formed by a printed circuit board 27a and switch bodies 27b formed by rubber switches attached to the printed circuit board 27a on a key-by-key basis. The key switches 27 are mounted on the keyboard chassis 2 in a state in which a rear end of the printed circuit board 27a is inserted into the chassis intermediate portion 12 and a front end of the same is screwed to the chassis front 11.
The chassis rear 13 has a key support section 28 that supports a pivot shaft 5a, referred to hereinafter, provided on a rear end of each key 5, to thereby support the key 5 such that the key 5 is pivotally movable about the pivot shaft 5a. Further, an upper limit stopper 29 for restricting the upper limit position of an associated one of the hammers 6 is attached to a rear end of a lower surface of the key support section 28. Furthermore, a front end of the key support section 28 has a rear-side key guide 28a erected therefrom between the rear ends of each adjacent two of the keys 5 and 5. Each two of the rear-side key guides 28a and 28a prevent lateral swing of the rear end of one of the keys 5 located therebetween.
Between the chassis rear 13 and the chassis intermediate portion 12, there is provided a flat plate 31 extending substantially horizontally between the keys 5 and the hammers 6. This flat plate 31 has a plurality of intermediate key guides 32 (only one of which is shown in
Each key 5 is formed e.g. by injection molding of a predetermined resin material (e.g. AS resin) such that it extends in a front-rear direction (in a left-right direction as viewed in
As shown in
On the other hand, the black key 4 has an actuator portion (not shown), which protrudes downward from a front end thereof over a predetermined length. Similar to the actuator portion 3b of the white key 3, the actuator portion of the black key 4 is engaged with the associated engagement recess 36b of the hammer 6 in a state received therein.
As shown in
A weight mounting portion 37 forming a rear half of the hammer body 34 has an opening 37a open rightward (toward the near side as viewed in
On the other hand, the weight 35 is formed of a material (metal such as steel) larger in specific gravity than the hammer body 34. The weight 35 is formed by pressing a metal plate having a smaller thickness than the thickness (thickness in the depth direction as viewed in
Next, the intermediate rail 15 and a lower limit stopper 30 mounted on the keyboard chassis 2 will be described with reference to
The intermediate rail 15 is made of a predetermined metal (e.g. galvanized steel plate (SECC) or aluminum alloy), and is formed in a C shape opening downward in transverse cross-section by a front wall 15a, an upper wall 15b, and a rear wall 15c thereof. Further, the intermediate rail 15 has a front end of the upper wall 15b thereof screwed to the chassis intermediate portion 12 by a mounting screw 38 in a state in which the front wall 15a is in intimate contact with a drooping wall 12b of the chassis intermediate portion 12 from rear. The front wall 15a of the intermediate rail 15 is sandwiched in the front-rear direction between the drooping wall 12b of the chassis intermediate portion 12 and a clip member 39 fitted from below. Note that the clip member 39 is made of rubber or synthetic resin and is configured such that vibration from the chassis intermediate portion 12 toward the keybed 10 can be suppressed. Further, the clip member 39 may be configured such that a nonwoven fabric or a felt is affixed thereto as a buffer.
The intermediate rail 15 mounted on the chassis intermediate portion 12 as described above is disposed in a state floating from the keybed 10 as shown in
Further, the lower limit stopper 30, which extends along the longitudinal direction of the intermediate rail 15 (in the depth direction as viewed in
As described hereinabove, when the keyboard device 1 having the lower limit stopper 30 arranged on the intermediate rail 15 is in the key-released state, as shown in
In the keyboard device 1 constructed as above, when the key 5 is depressed from the key-released state shown in
On the other hand, when the depressed key 5 is released, as shown in
Now, the positional relationship between the hammer 6 and the lower limit stopper 30 will be described in more details with reference to
By setting the positional relationship between the hammer 6 and the lower limit stopper 30 as described above, compared with e.g. a case where a portion 35a, which is located closer to the rear end of the hammer 6 than a center position of the hammer 6 is, moves into contact with a lower limit stopper 40 located below the portion 35a, a distance P between the placement-contact portion 6a of the hammer 6, which is located at the upper limit position of the hammer 6 (when the hammer 6 starts to pivotally move downward), and the lower limit stopper 30, is much shorter than a distance Q between the above-mentioned portion 35a and the lower limit stopper 40.
As described above in detail, according to the present embodiment, the intermediate rail 15 is mounted on the keyboard chassis 2 below the pivot shaft 12a for the plurality of hammers 6 and its vicinity, and the lower limit stopper 30 is mounted on the intermediate rail 15. Differently from the conventional keyboard device, which has a lower limit stopper (e.g. the lower limit stopper 40 in
Further, since the lower limit stopper 30 is formed of an elastic material, it is possible to absorb impact on the lower limit stopper 30 when the hammer 6 is brought into contact therewith, to thereby further reduce noise generated by the contact.
Note that the present invention is not limited to the above-described embodiment, but it can be practiced in various forms. For example, although in the above-described embodiment, the keyboard device 1 of the present invention is applied to an electronic piano, the present invention is not limited to this, but it can be applied to other keyboard instruments. Further, details of the constructions of the keyboard chassis 2, the keys 5, the hammers 6, the intermediate rail 15, and the lower limit stopper 30 shown in the embodiment are given only by way of example, and they can be changed as appropriate within the scope of the subject matter of the present invention.
Number | Date | Country | Kind |
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JP2020-153438 | Sep 2020 | JP | national |
Number | Name | Date | Kind |
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5612502 | Ura | Mar 1997 | A |
8247672 | James | Aug 2012 | B2 |
8927848 | Kaneko | Jan 2015 | B2 |
9082372 | Suzuki | Jul 2015 | B2 |
9613608 | Osuga | Apr 2017 | B2 |
9940916 | Suzuki | Apr 2018 | B2 |
10115382 | Nishimura | Oct 2018 | B2 |
10347223 | Taniguchi | Jul 2019 | B2 |
10418003 | Taniguchi | Sep 2019 | B2 |
10902830 | Nishida | Jan 2021 | B2 |
11037542 | Okamoto | Jun 2021 | B2 |
20220084484 | Suzuki | Mar 2022 | A1 |
Number | Date | Country |
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2009-75404 | Apr 2009 | JP |
Number | Date | Country | |
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20220084484 A1 | Mar 2022 | US |