Music – Instruments – General features
Reexamination Certificate
2001-05-02
2003-03-11
Hsieh, Shih-Yung (Department: 2837)
Music
Instruments
General features
C084S438000, C084S439000, C084S440000, C084S45200P, C084S45200P
Reexamination Certificate
active
06531651
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a key for use in a piano and so on, and more particularly, to a key which has a weight attached thereto to provide a desired touch load.
2. Prior Art
FIG. 1
illustrates a conventional key (white key) for a grand piano. This key
51
is comprised of an elongated key body
52
made of wood and having a rectangular cross section; a white key cover
53
made of plastic covering a front region of the key body; a plurality (three in this example) of weights
54
attached on a side face of the key body
52
; and so on. The key body
52
is swingably supported by a balance pin (not show) at the center thereof, and an action (not shown) is carried thereon in a region behind the balance pin.
FIG. 2
illustrates a conventional black key, the configuration of which is basically identical to that of the white key. A sharp key cover
58
, which is made of plastic, is formed with a recess open to below, and is adhered to a front region of the top face of the key body
52
to cover the same.
The weights
54
are attached to provide a desired touch load (static load) for the key, and are each made of lead of a predetermined size molded into a cylindrical shape. On the other hand, the key body
52
is formed with three circular embedding holes
55
of a predetermined size which laterally extend through the key body
52
at predetermined positions in a front region thereof. The weights
54
are filled in these embedding holes
55
, and then caulked for attachment to the key body
52
. The lead is employed as the weights
54
in this manner because the lead has a high specific gravity (approximately 11.3) among metals, is inexpensive, and exhibits high flexibility and ductility which facilitate works as mentioned above.
Generally, the touch load may be adjusted after the weights
54
have been attached as described above for purposes of eliminating variations in touch load among keys and of matching the touch load for a player's preference. For adjusting the touch load, a side face of a weight
54
is cut away for reducing the touch load since the weight
54
is attached by caulking and therefore removed with difficulties. On the other hand, for increasing the touch load, at least one of previously provided separate adjusting weight
56
, made of lead, is additionally attached to the key body
52
, as indicated by broken lines in
FIG. 1
, for the same reason. In this event, a position for attaching the adjusting weight
56
is first determined such that the moment imparted by the adjusting weight
56
about the balance pin is appropriately produced in accordance with the touch load to be added. Then, an embedding hole
57
is additionally formed at the determined attaching position on the key body
52
, followed by caulking the adjusting weight
56
for attachment. These works are performed for each key
51
.
In the conventional key
51
described above, lead is used as the material for the weights
54
for the reasons mentioned above. However, since lead is an injurious material, it is desirable that lead is used for the weights of the keys as least frequently as possible, so that an alternative material is needed for substitution for lead. Also, since the conventional key
51
involves caulking for attaching the weights
54
to each key body
52
, this work itself is laborious. Also, due to difficulties in removal of the weights
54
attached by caulking, and due to the constant specific gravity of the weights
54
, the adjustment of the touch load involves the works which include cutting away the side face of a weight
54
, forming an embedding hole
57
into the key body
52
while determining a position at which an adjusting weight
56
is attached, and attaching the adjusting weight
56
for each key
51
, as described above. As a result, the adjusting works require significant efforts, resulting in an increase in the manufacturing cost. Further, the attachment of the adjusting weight
56
requires the formation of the embedding hole
57
laterally extending through the key body
52
, in addition to the original embedding holes
55
, thereby giving rise to a problem that the strength of the key body
52
tends to be insufficient.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the problems as mentioned, and specifically to provide a key which is capable of facilitating the attachment of a weight, and adjustments of a touch load, while using an alternative material for substitution for lead as a material for the weight, thereby reducing the manufacturing cost.
To achieve this object, a key according to a first invention is characterized by comprising a swingable key body formed with an embedding hole; and a weight made of a composite material produced by blending a plurality of kinds of materials except for lead in a predetermined blending proportion so as to have a predetermined specific gravity, and removably attached to the embedding hole of the key body.
According to this key, the weight is made of a composite material produced by mutually blending a plurality of kinds of materials except for lead in a predetermined blending proportion, and removably attached to the embedding hole formed in the key body to add a weight to the key body. In this case, the specific gravity of the entire composite material thus blended can be made equivalent to that of lead by using, for example, a suitable high specific gravity metal as one of the materials except for lead. Therefore, the composite material thus composed can be used as an alternative material for the weight for substitution for conventionally used lead. Also, since the weight made of the composite material can be removably attached to the embedding hole, the attachment and removal of the weight can be readily carried out as compared with the conventional one which is caulked for attachment.
In this case, preferably, one of the plurality of kinds of materials comprises an elastic material, so that the weight has elasticity, and is removably attached to the embedding hole of the key body through press fitting.
In this configuration, the weight made to have elasticity given by one of the materials comprising an elastic material can be attached to the embedding hole through simple press fitting, so that the attachment and removal of the weight become more easy than the conventional caulked one, thereby making it possible to reduce the manufacturing cost by simplifying the works involved in attaching the weight.
In this case, preferably, the elastic material comprises rubber, and another one of the plurality of kinds of materials comprises powdered tungsten.
Tungsten is harmless and has a very large specific gravity (approximately 19.3), so that it is particularly suitable for achieving a specific gravity in a required range which includes a specific gravity equivalent to lead, with a blend of rubber. Also, since the rubber, which comprises an elastic material, serves to ensure the elasticity of the weight, and is relatively inexpensive, the material cost can be reduced correspondingly.
In these cases, preferably, the weight comprises a plurality of types of weights made by blending the elastic material and the other one of the plurality of kinds of material in different blending proportions from one another to have different specific gravities from one another.
In this configuration, since the weight comprises a plurality of types of weights having different specific gravities, the weight can be made different without changing the size thereof. Therefore, for example, the touch load can be readily adjusted by previously providing a plurality of weights having the same shape and size as one another and different weights, and selecting one having an appropriate weight from these weights for attachment to the embedding hole. This results in complete elimination of the cutting of the weight for reducing the touch load, and the additional provision and positioning of an embedding hole and a weight for adjustment for increasing t
Abiko Masahiko
Kanemitsu Makoto
Kurita Hiroyuki
Yamashita Mitsuo
Crowell & Moring LLP
Hsieh Shih-Yung
Kabushiki Kaisha Kawai Gakki Seisakusho
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