1. Field of the Invention
The invention relates to a keyboard apparatus used in electronic keyboard instruments such as an electronic organ, an electronic piano, and a synthesizer, or in electric keyboard instruments.
2. Description of the Related Art
As a keyboard apparatus used in electronic keyboard instruments such as electronic organs and electronic pianos, there has conventionally been provided a comb-teeth shaped keyboard apparatus such as that disclosed in, for example, JP H06-342281 A. This keyboard apparatus is structured such that a plurality of key main bodies to which a key depression operation is performed are coupled via thin coupling parts to a common key support part extending in a key arrangement direction and are supported to be pivotable in a key depression direction, and they are integrally formed of resin to form a comb-teeth shaped key unit. For example, in each one octave key range, a white key unit consisting of four alternate white keys, a white key unit consisting of the remaining three white keys, and a black key unit consisting of five black keys are separately formed, the respective common key support parts are integrally stacked, and the integrated key unit is fixed to a key mounting part of a keyboard frame with screws. Such integrated key units in number corresponding to a necessary key range are connected, whereby a keyboard apparatus is structured.
With this structure, since it is not necessary to provide fulcrum parts in the keyboard frame and the plural keys are integrated as a unit, the less number of components are required and the assembly maintenance are easy, which is extremely effective for reducing manufacturing cost.
However, it has been necessary to provide a key guide for each key in order to restrict the key arrangement direction position of each key and to prevent yawing at the time of key depression.
Therefore, there has been proposed a comb-teeth shaped keyboard apparatus requiring no key guide as disclosed in JP H07-92963 A. In the keyboard apparatus, a total width in a key width direction of a coupling part in each key unit as described above is larger than a width of a rear end of a key main body, thereby realizing sufficient flexibility in a key depression/release direction yet increasing a sectional secondary moment against a force in the key width direction (lateral direction). Accordingly, it is possible to restrict yawing in the key width direction of the key main bodies without using any key guide, resulting in reduced manufacturing cost of the keyboard apparatus.
Further, a keyboard apparatus of an electronic musical instrument as disclosed in, for example, U.S. Pat. No. 5,834,668 B has been conventionally in use. In this keyboard apparatus, in order to provide a heavy key touch feeling comparable to a key touch feeling of an acoustic musical instrument such as a piano, mass members such as hammers are provided for respective keys. Each of these hammers pivots in linkage with a depression operation of each key to produce a force depending on its movement, and the force works as a counter force against a key depression force, thereby providing a desired key depression touch feeling.
However, the comb-teeth shaped keyboard apparatus as disclosed in JP H06-342281 A requires the key guides for the respective keys, which has posed a problem that the structure of the whole keyboard apparatus cannot be sufficiently simplified and it takes time to adjust the positions of the key units and the key guides.
Here, structuring the key units as disclosed in JP H07-92963 A maybe disuse the key guides. However, it is necessary to make the coupling parts sufficiently wide in the key width direction so that the coupling part of each key partly overlap in plane with the coupling parts of the adjacent keys when the keyboard apparatus is assembled by stacking the common key support parts of the plural key units. Otherwise, key guides need to be provided on a key free end side. Therefore, the shape of the key units and the structure of the keyboard become complicated, resulting in increased molding cost and design restrictions.
Moreover, in a case of a mini keyboard whose keys are shorter than keys in a standard keyboard, such a structure with the wide coupling parts can sufficiently restrict yawing of key main bodies, but in a case of a standard keyboard, it is difficult to sufficiently restrict yawing of key main bodies (especially, white keys) only by the wide coupling parts since the key main bodies are long, which poses a problem of bad performability such as difficulty in playing glissando.
Further, in the keyboard apparatus having the mass members operating in linkage with the respective keys as disclosed in U.S. Pat. No. 5,834,668 B, a large number of members such as key guides and key switches for the respective keys, mechanisms for linking the keys and the mass members (hammers), and upper/lower limit stoppers of the mass members have to be provided under the keys, which imposes many restrictions on the shape, arrangement, movable range, and so on of the mass members, and therefore it has been extremely difficult to design the keyboard apparatus providing a desired touch feeling and being low cost.