Patent Grant
7268285
1. Field of the Invention
The present invention relates to a key structure which is applied to a key having a wood part, and a keyboard apparatus including the key structure.
2. Description of the Related Art
Conventionally, key structures are known which function as a key pivotally moved by key depression and for which wood or the like is used, as disclosed in Japanese Utility Model Registration Publication No. 2514485 and Japanese Laid-Open Patent Publication (Kokai) No. 2903959. In such a woody key structure, a woody material is used at least for a so-called “visible part” which is visible from the outside during both performance and non-performance, the key structure presents a woody appearance and hence a high-quality appearance.
In the woody key structure, the wood part is supportedly fixed e.g. using an adhesive to the lower surface of an upper plate member having a depressing surface, or to the upper surface of a key base body as a lower plate member. The support members, such as the upper plate member and the key base body, have elongated shapes corresponding to the shape of the key, and these support members and the wood part form the key structure.
Differently from synthetic resin which can be accurately shaped by molding, wood, which cannot be molded, is formed into a desired shape basically by cutting or machining. For example, to make the width of the key structure equal to a predetermined width set for each key of the keyboard apparatus, it is necessary to cut or machine the left and right sides of the key structure which includes the wood part. In this operation, generally, the key structure is cut for width adjustment using a cutting tool, such as a rotary tool, which is moved in the longitudinal direction along the key structure, so as to make the width of the key structure uniform along the length thereof.
However, the key structure may include a region in the longitudinal direction where no wood part exists, e.g. as in the case where the key structure has a rear end part formed of only resin without any wood part. When the cutting tool moves along such a region of the key structure as the above-mentioned rear end part where only a resin part exists without any wood part, the cutting blade of the cutting tool is brought into contact with a wide region of the resin part. Machining conditions suited to resin parts are different from those suited to wood parts, and therefore the edge of the cutting blade tends to cut undesirably deep into the resin part to cause damage, such as cracking or chipping, to the resin part.
Further, depending on the shape of a bonded part between the wood part and the support member, the rigidity of the key structure itself can be low or the rigidity can vary along the length of the key structure, so that stress can be concentrated on parts low in rigidity, i.e. weak parts, which can cause a deformed or damaged key structure. For example, when an appropriate clearance having a longitudinal component is provided between the wood part and the support member so as to accommodate variations in the longitudinal dimensions of the two parts, the clearance can produce the least rigid part of the key structure. Such a discontinuity in rigidity of the key structure is undesirable since it brings about the reduced rigidity of the key. In spite of these circumstances, there is a constant demand for the reduction of sizes and weights of keys and keyboard apparatuses.
It is a first object of the present invention to provide a key structure which has a key formed by a wood part so as to present a woody appearance and which makes it possible to prevent support members thereof that support the wood part from being damaged during machining of the wood part for width adjustment, and a keyboard apparatus having the key structure.
It is a second object of the present invention to provide a key structure which has a key formed by a wood part so as to present a woody appearance and which makes it possible not only to reduce the longitudinal size of the key structure, but also to achieve enhancement and uniformity of rigidity of the key structure in the longitudinal direction, and a keyboard apparatus having the key structure.
To attain the above first object, in a first aspect of the present invention, there is provided a key structure (600, 700) that is mounted in a keyboard apparatus, for functioning as a key pivotally moved by key depression, comprising a wood part (111, 115) that includes a narrow part (111M, 115M) having opposite lateral sides (111a, 111b, 115a, 115b), and an elongated support member (110, 116) that has opposite lateral sides (110c, 110d, 116c, 116d), and fixedly supports the wood part, and the support member has recessed parts (110a, 110b, 116a, 116b) formed in the respective lateral sides thereof at least in a substantial entirety of a region (AR1, AR3) of the support member in a longitudinal direction where the wood part does not exist, the recessed parts being recessed laterally inward of the respective lateral sides of the narrow part of the wood part.
With the arrangement of the first aspect of the present invention, the key presents a woody appearance due to the wood part. Further, the recessed parts are formed in the opposite lateral sides of the support member in the substantial entirety of the region where the wood part does not exist, in a manner being recessed laterally inward of the narrow part of the wood part, which makes it possible to prevent the blade of the cutting tool from being brought into contact with the support member during machining of the wood part for width adjustment.
Preferably, the wood part includes an upper part, and the support member comprises an upper plate part that has a top surface used as a depressing surface, and is disposed on the upper part of the wood part, and a key base body that supports the wood part from below, the key base body having a shape in plan view such that the key base body is applicable to any of keys for a pitch A, a pitch C, a pitch E, and a pitch G, as non-dash keys which are disposed in positions other than opposite ends of the keyboard apparatus, the key base body being configured for use in both any of dash keys for the pitch A, the pitch C, the pitch E, and the pitch G, disposed at the opposite ends of the keyboard apparatus, and any of the non-dash keys, in a manner such that the key base body selectively supports the wood part and the upper plate part that are configured for the dash keys, and the wood part and the upper plate part that are configured for the non-dash keys.
To attain the above second object, in a second aspect of the present invention, there is provided a key structure (600, 700, 800) that is mounted in a keyboard apparatus, for functioning as a key pivotally moved by key depression, comprising a wood part, an elongated support member that has a rear part, and fixedly supports the wood part, and a rib (112, 117, 217) that has opposite lateral side surfaces vertically in substantial parallel relationship with each other and extends from the rear part of the support member toward a player side and the wood part, and the wood part has a recess (113, 118, 218) formed therein, in which the rib is fitted or received.
With the arrangement of the second aspect of the present invention, the key presents a woody appearance due to the wood part. Further, the support member is formed with the rib, and therefore the rigidity of the support member in the longitudinal direction is enhanced and made more uniform. Furthermore, the rib is received in the recess of the wood part, which enables space saving mainly in the longitudinal direction of the key structure, compared with a structure in which the rib is not received in the wood part.
To attain the above second object, in a third aspect of the present invention, there is provided a key structure (600, 700, 800) that is mounted in a keyboard apparatus, for functioning as a key pivotally moved by key depression, comprising an elongated support member that has a rear part, a wood part that is fixedly supported by the support member, the wood part being disposed at a location forward of the rear part of the support member such that the wood part extends toward a player side, with a clearance (CL1, CL3, CL5) provided between the rear part of the support member and the wood part, the clearance having a longitudinal component, and a rib (112, 117, 217) that has opposite lateral side surfaces vertically in substantial parallel relationship with each other and extends from the rear part of the support member, toward the player side and the wood part at least in the clearance, and the wood part has a recess (113, 118, 218) formed therein, in which the rib is fitted or received.
With the arrangement of the third aspect of the present invention, the key presents a woody appearance due to the wood part. Further, the support member is formed with the rib, and therefore the rigidity of the support member in the longitudinal direction is enhanced and made more uniform. Furthermore, the rib is received in the recess of the wood part, which enables space saving mainly in the longitudinal direction of the key structure, compared with a structure in which the rib is not received in the wood part. Moreover, the rib extends at least in the clearance between the wood part and the support member, the weakest part of the key structure can be effectively reinforced.
Preferably, at least one of thickness of the rib in a vertical direction thereof and thickness of the rib in a transverse direction of the key increases toward a rear end of the rib.
With the arrangement of the preferred embodiment, it is possible to disperse stress in the longitudinal direction, thereby making the key structure further uniform in rigidity. Also, when the thickness of the rib in the transverse direction of the key (in the transverse direction) is increased toward the rear end of the rib, it is possible to enhance torsional rigidity of the key structure, thereby increasing rolling resistance of the same. For example, the rib is formed into a trapezoidal shape in plan view with a base side in the rear of the key, and a shape in side view, in which the lower and upper ends of the rib are sloped downwardly and upwardly toward the rear end, respectively. Furthermore, this key structure makes it possible to minimize the recess of the wood part, thereby reducing the amount of machining of the recess.
Preferably, thickness of the rib in a transverse direction of the key increases toward the support member.
With the arrangement of the preferred embodiment, it is possible to prevent concentration of distortion due to a load in a rolling direction on a particular part of the key structure, thereby making uniform the rolling resistance of the same.
More preferably, the support member comprises an upper plate part that includes a top surface for use as a depressing surface, and is disposed on the upper part of the wood part, and a key base body that supports the wood part from below, and the rib is formed such that the rib extends from the key base body, but does not reach the upper plate part.
With the arrangement of the preferred embodiment, as is distinct from the case where the rib is continuous with the upper plate part, a sink mark formed at the root of the rib appears not on the top surface of the key structure, but on the lower surface of the key base body. Therefore, it is possible to prevent a sink mark from being formed on the visible portion visible from the outside to thereby avoid degradation of the appearance of the visible part.
To attain the above first object, in a fourth aspect of the present invention, there is provided a keyboard apparatus comprising keys having a key structure according to the first aspect of the invention.
To attain the above second object, in a fifth aspect of the present invention, there is provided a keyboard apparatus comprising keys having a key structure according to the second aspect of the invention.
To attain the above second object, in a sixth aspect of the present invention, there is provided a keyboard apparatus comprising keys having a key structure according to the third aspect of the invention.
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 key structure 600 according to the first embodiment functions as one of a plurality of keys of a keyboard apparatus used mainly as a musical instrument (musical keyboard instrument), which are pivotally moved by key depression. The key structure 600 is applied to a B key (white key for a pitch B) of the keyboard apparatus, for example. The construction of the key structure 600 may be applied not only to a white key but also to a black key. In the following description, a side of the key structure 600 toward the player will be referred to as “the front side” and a right side of the same as viewed from the player will be referred to as “the right side”.
The key structure 600 is comprised of an upper plate body (support member) 110 made of synthetic resin and formed in one piece by molding, and a wood part 111 made of wood. As shown in
The wood part 111, which has approximately the same length as a front part of the upper plate body 110, extends forward of the rear end part 110B, and is fixedly bonded to the underside surface of the front part of the upper plate body 110 such that a longitudinal clearance CL1 is provided between the wood part 111 and the rear end part 110B. The clearance CL1 serves mainly to accommodate variations in the longitudinal dimensions of the wood part 111 and the rear end part 110B, and also to prevent expansion and contraction or deformation of the wood part 111 due to changes in the environment from causing degradation of the bonded status of the wood part 111 and the upper plate body 110. The wood part 111 is made of an elongated wood block, and has the same width as that of the upper plate body 110 with the same side profiles as those of the latter, such that the wood part 11 is exposed to opposite side surfaces of the key structure 600.
The wood part 111 plays the role of making the key structure 600 present a woody appearance. When an adjacent key is depressed, a side surface of the key structure 600 is exposed to the view of the player. The wood part 111 made of wood is disposed such that it is visually recognized as part of a side of the key structure 600 when the adjacent key is depressed, so that the key structure 600 appears as if it were made of wood except for its upper and front surfaces. This makes the key structure 600 present a woody appearance and hence a high-quality appearance.
As shown in
On the other hand, the narrow part 111M of the wood part 111 is formed by machining, i.e. cutting. Before machining, the width of the wood part 111 is set to be larger than a predetermined width thereof. For example, the wood part 111 is initially formed such that it has the same width set to the width of the wide player-side end thereof along the length thereof from the front end to the rear end. Then, after the wood part 111 is fixedly bonded to the upper plate body 110, the narrow part 111M is machined such that it has the same width as that of the B key of the keyboard apparatus, and thus the narrow part 111M forms a narrowest part of the wood part 111. The machining for width adjustment is performed by cutting the wood part 111 using a cutting tool, such as a rotary tool, which is moved longitudinally.
The above-mentioned recessed parts 110a and 110b formed in the rear end part 110B of the upper plate body 110 makes it possible to avoid interference of the blade of the cutting tool with the rear end part 110B. More specifically, while the rear end part 110B has a wide part thereof formed of synthetic resin in side view, the machining is carried out under machining conditions (cutting conditions including feeding speed, cutting speed, and so forth) suitable for the wood part 111. Further, the machining is generally performed by clamping the region including the wood part 111 but without clamping the rear end part 110B.
On the other hand, if the recessed parts 110a and 110b were not formed, the blade of the cutting tool interferes with the rear end part 110B. Therefore, the provision of the recessed parts 110a and 110b makes it possible to prevent the rear end part 110B in the region AR2 from being cracked, chipped, or damaged. Further, since the rear end part 110B is not a visible part which can be seen from the outside during performance, the appearance of the key structure 600 cannot be adversely affected by the rear end part 110B. The recessed parts 110a and 110b may be formed so as to extend along the entirety of the region AR1 where the wood part 111 does not exist, or beyond the region AR1.
As shown in
According to the present embodiment, when an adjacent key is depressed, the wood part 111 of the key is viewed as part of a side of the key by the player, which gives a woody appearance and hence a high-quality appearance to the key. Further, in the substantial entirety (region AR2) of the region AR1 where the wood part 111 does not exist, the recessed parts 110a and 110b are formed in the rear end part 110B, which makes it possible to avoid interference of the cutting tool with the rear end part 110B during the machining of the wood part 111 for width adjustment, to thereby prevent damage to the upper plate body 110.
Further, according to the present embodiment, since the upper plate body 110 is formed with the rib 112, the upper plate body 110 itself has enhanced rigidity and enhanced uniformity of rigidity. Furthermore, since the rib 112 is formed in a manner connecting between the rear end part 110B and the wood part 111 through the clearance CL1, the weakest part of the key structure 600 is effectively reinforced, which enhances the rigidity and uniformity-thereof in the entire key structure 600 in the longitudinal direction. Moreover, the thickness of the rib 112 progressively increases from a front end of the rib 112, where the rib 112 has no thickness, toward a rear end thereof and continues to the rear end part 110B, which prevents stress caused by key depression from being concentrated on a particular part of the key structure in the longitudinal direction, thereby dispersing the stress to make the rigidity of the key structure 600 further uniform, leading to enhanced durability of the key structure 600. In addition, since the rib 112 is received in the groove 113 of the wood part 111, the overlap of the two components mainly in the longitudinal direction promotes space saving, compared with a structure in which the rib 112 is not received in the wood part 111, which contributes to reduction of the size of the key structure 600.
The rib 112 may have a rectangular shape in side view instead of a triangular shape in side view, which also makes it possible to obtain enhanced rigidity of the key structure 600. However, considering the fact that the key structure 600 has a sufficient degree of rigidity in the region where the rib 112 is fitted in the groove 113 of the wood part 111, but a lowest degree of rigidity in the region of the clearance CL1, the rib 112 is formed in the present embodiment such that the vertical thickness (height) thereof is maximized in the region of the clearance CL1 and progressively decreased toward the front end of the rib 112, whereby discontinuous variations in the rigidity of the key structure 600 in the longitudinal direction are minimized to thereby make the rigidity as uniform as possible, and at the same time, the region of the wood part 111, where the groove 113 is formed, is minimized in area and volume to thereby reduce the amount of groove machining.
The term “substantial parallel relationship” between the opposite side surfaces of the rib 112 in the vertical direction includes tolerances of an angle between the opposite side surfaces of the rib 112, which may be 1 to 10 times as large as the draft angle of the mold (i.e. an angle of not larger than eight degrees).
Next, a description will be given of a second embodiment of the present invention, which is distinguished from the first embodiment in which the upper plate body 110 is used as a support member that fixedly supports the wood part 111, in that a key base body is used as a support member.
The key structure 700 of the second embodiment is also applied to a B key, for example. The construction of the key structure 700 may be applied not only to a white key but also to a black key. In the following description, a side of the key structure 700 toward the player will be referred to as “the front side” and a right side of the same as viewed from the player will be referred to as “the right side”.
The key structure 700 is comprised of an upper plate body 114 and a key base body (support member) 116, each of which is formed of synthetic resin and formed by the mold, and a wood part 115 made of wood. As shown in
The wood part 115 has approximately the same length as the wood part 111 in the first embodiment, and is fixedly bonded to the lower surface of the upper plate body 114 and the upper surface of a part of the key base body 116 extending forward of a rear end part 116B of the same, such that a clearance CL3 having a longitudinal component is provided between the wood part 115 and the rear end part 116B. The clearance CL3 plays the same role as the clearance CL1 (see
As shown in
Further, as shown in
In association therewith, the wood part 115 has a groove 118 having a width large enough to have the rib 117 fitted therein, formed at a location corresponding to the rib 117. Further, a clearance CL4 is formed between the groove 118 and a sloped player-side upper end (a sloped surface facing obliquely forward and upward). The fitting and receiving relationship between the rib 117 and the groove 118 is similar to that between the rib 112 and the groove 113 in the first embodiment, and the clearance CL4 plays the same role as the clearance CL2.
According to the present embodiment, it is possible not only to provide the same advantageous effects as provided by the first embodiment, but also to prevent generation of a sink mark on the upper surface of the upper plate body 114, thereby ensuring excellent appearance of the upper plate body 114.
In the present embodiment, the key base body 116 is has the uniform width J2 except the wide player-side end part. However, from the viewpoint of prevention of damage to the rear end part 116B of the key base body 116 during machining of the wood part 115 for width adjustment, it suffices to make the width of the rear end part 116B smaller than the width W2 of the narrow part 115M of the wood part 115 only in the substantially entire region of the region AR3 where the wood part 115 does not exist, so as to provide the rear end part 116B with recesses which are indented transversely inward with respect to the narrow part 115M.
The third embodiment is distinguished from the second embodiment in which the rib 117 is in the form of a thin plate having the opposite side surfaces thereof longitudinally and vertically in substantial parallel relationship, in that a rib 217 of the key structure 800 according to the third embodiment has a trapezoidal shape in plan view. The key structure 800 is comprised of an upper plate body 214, a wood part 215, a key base body (support member) 216, a rear end part 216B of the key base body 216, and a pivot 219, which are slightly different in shape but basically identical in construction to the upper plate body 114, the wood part 115, the key base body 116, the rear end part 116B of the key base body 116, and the pivot 119, of the key structure 700, respectively, of the second embodiment.
As shown in
On the other hand, the wood part 215 has a recess 218 where the rib 217 is loosely fitted, formed at a location corresponding to the recess 218. Further, as shown in
According to the present embodiment, it is possible to provide the same advantageous effects as provided by the second embodiment. Further, since the thickness of the rib 217 in the transverse direction progressively increases toward the rear end thereof, it is possible to enhance torsional rigidity of the key structure 800, thereby increasing rolling resistance of the same. Particularly in B, C, E, and F keys, the difference in position between the center of the wide player-side front half of the key in the transverse direction and that of the narrow rear half of the same in the same direction is large (i.e. the degree of transverse asymmetry is high), and therefore the key tends to undergo a large load in the rolling direction during performance. An oblique component of the rib 217 produced with respect to the center of the key in the transverse direction due to the trapezoidal shape of the lib 217 in plan view can act effectively against the torsional load to suppress rolling.
In the first and second embodiments as well, with a view to suppressing the rolling, the rib 112 (117) may be formed such that the opposite side surfaces thereof longitudinally extend not in parallel relationship but slightly obliquely with respect to the center in the transverse direction (the longitudinal axis), or a pair of ribs 112 (117) may be formed such that they form the same angle as formed by the opposite side surfaces of the rib 217. Alternatively, another rib having an oblique component may be formed in addition to the rib 112 (117).
Although in the third embodiment, the opposite side surfaces of the rib 217 vertically extend in parallel relationship, this is not limitative, but the opposite side surfaces may extend vertically at an angle 1 to 10 times as large as the draft angle of the mold (i.e. an angle of not larger than eight degrees), for example, such that the thickness of the rib 217 in the transverse direction increases toward a lower end of the rib 217. This configuration makes it possible to prevent distortion or stress caused by the load in the rolling direction from being concentrated on a specific part of the key structure, whereby the rolling resistance can also be made uniform. When this configuration is reflected in the key structure 800 in
Although in the first to third embodiments described hereinabove, the upper plate body or the key base body is used as a support member that fixedly supports the wood part, this is not limitative, but the present invention is applicable to a case where the upper plate body and the key base body are formed in one piece so as to serve as the support member. Alternatively, the present invention can be applied to a configuration in which the upper plate body and the key base body are formed in separate bodies, with the rear end parts of the two members lying at a location corresponding to the rear end part of the key structure but the wood part not existing there, and the rear end parts of the two members are both formed in a fashion being recessed laterally inward of the narrow part of the wood part, whereby damage to the rear end parts can be prevented.
In the first to third embodiments described hereinabove, insofar as the presentation of the woody appearance is concerned, the wood part need not be formed of wood, but it can be formed of a woody material. For example, a woodgrain decorative panel (a printed panel, a coated panel, a painted panel, sliced veneer), plywood, a medium density fiberboard (MDF), or the like may be employed.
Although the key base body 116 in the second embodiment is used for the B key, if the key base body 116 is formed into such a shape that it can be applied to any of an A key, a C key, an E key, and a G key, the key base body 116 can also be used for the key structure of a corresponding dash key.
Dash keys are white keys which are disposed at the left and right ends of a keyboard, with no black keys provided outward thereof. For example, in an 88-key keyboard, the pitch of the lowest-pitch key is “A” and that of the highest-pitch key is “C”. In a 76-key keyboard, the pitch-of the lowest-pitch key is “E” and that of the highest-pitch key is “G”. Now, taking as an example the lowest-pitch key (A key) as the left-end dash key in the 88-key keyboard, each of the other A keys than the dash key has a left side part thereof formed with an recessed part to avoid interference with a left adjacent black key of the pitch “G#”, but the A dash key, which need not be formed with a recessed part, is different in shape in plan view from the non-dash keys.
However, since the dash key has a shape in plan view which is larger in thickness than the corresponding non-dash key, if only a key base body for the dash key is formed into the same shape as that of the key base body 116 of the key structure shown in
As described above, the key base body for a non-dash key of any of the pitches A, C, E and G can be used for both a non-dash key and a dash key, by being selectively combined with the upper plate body and the wood part for the non-dash key and those for the dash key, which contributes to reduction of the number of component parts and elements. This is the same with the key base body 216 of the key structure 800 of the third embodiment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-320965 | Sep 2003 | JP | national |
| 2004-121734 | Apr 2004 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2844065 | Corwin | Jul 1958 | A |
| 3120146 | Stiles | Feb 1964 | A |
| 3417649 | Wood | Dec 1968 | A |
| 3756113 | Suzuki et al. | Sep 1973 | A |
| 4512234 | Kumano | Apr 1985 | A |
| 4840104 | Ishida et al. | Jun 1989 | A |
| 5559297 | Yoshikawa et al. | Sep 1996 | A |
| 6693235 | Ookubo | Feb 2004 | B2 |
| 20050145093 | Nishida et al. | Jul 2005 | A1 |
| Number | Date | Country |
|---|---|---|
| 2514485 | Jul 1996 | JP |
| 2903959 | Mar 1999 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20050056136 A1 | Mar 2005 | US |
