ACTION OF GRAND PIANO

Abstract

An action of a grand piano, which makes it possible to reduce not only the weight of a jack, but also that of a wippen, to thereby improve string striking repeatability. The action includes a wippen of a synthetic resin configured to pivotally move upward by being pushed up by the depressed key, a jack pivotally mounted to the wippen, for pushing up the hammer in accordance with pivotal motion of the wippen to cause the hammer to pivotally move upward, and a jack angular position-adjusting mechanism provided on the wippen to adjust an angular position of the jack. The mechanism has a support portion integrally formed with the wippen, an adjustment screw screwed into the support portion movably in a front-rear direction, and a jack button provided on an end of the adjustment screw for defining the angular position of the jack by abutment therewith.

Claims

1. An action of a grand piano, which operates in accordance with depression of a key to thereby cause pivotal motion of a hammer, including: a wippen formed by a molded article of a synthetic resin and configured to pivotally move upward by being pushed up by the key subjected to key depression; a jack pivotally mounted to the wippen and configured to push up the hammer in accordance with pivotal motion of the wippen to cause the hammer to pivotally move upward; and a jack angular position-adjusting mechanism provided on the wippen so as to adjust an angular position of the jack, wherein the jack angular position-adjusting mechanism comprises: a support portion integrally formed with the wippen; an adjustment screw extending a predetermined length in a front-rear direction and screwed into the support portion such that the adjustment screw is movable forward and backward in the front-rear direction; and an abutment portion provided on a jack-side end of the adjustment screw, for defining the angular position of the jack by abutment with the jack.

2. The action of a grand piano, according to claim 1, wherein the wippen has a lever flange portion extending upward a predetermined length and pivotally supporting a repetition lever on which the hammer is placed, by an upper end thereof, and wherein the support portion includes: a pair of extension portions extending in parallel with each other from the lever flange portion of the wippen toward the jack, and an adjustment screw-engaging portion provided on tip ends of the pair of extension portions and having a screw hole formed therethrough through which the adjustment screw is screwed in a state extending between the pair of extension portions substantially along a direction of a length thereof.

3. The action of a grand piano, according to claim 1, wherein the abutment portion is mounted to the adjustment screw in a state in which the jack-side end of the adjustment screw faces outside, and wherein a portion, with which the abutment portion comes into abutment, of the jack is formed with an operation hole through which a predetermined tool can be inserted from a front side so as to turn the end of the adjustment screw.

4. The action of a grand piano, according to claim 2, wherein the abutment portion is mounted to the adjustment screw in a state in which the jack-side end of the adjustment screw faces outside, and wherein a portion, with which the abutment portion comes into abutment, of the jack is formed with an operation hole through which a predetermined tool can be inserted from a front side so as to turn the end of the adjustment screw.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1A is a side view of a keyboard device including an action of a grand piano, according to an embodiment of the present invention.

[0017] FIG. 1B is an enlarged perspective view of a jack angular position-adjusting mechanism and component parts associated therewith.

[0018] FIG. 2 is a perspective view of a jack button and an adjustment screw.

[0019] FIG. 3 is an enlarged view of a portion, which is in abutment with the jack, of the jack button, as viewed from the front of the jack.

[0020] FIGS. 4A and 4B are views useful in explaining adjustment of the jack, which is performed by turning the adjustment screw, in which FIG. 4A shows a state before the adjustment, and FIG. 4B shows a state after the adjustment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0021] The present invention will now be described in detail with reference to the drawings showing preferred embodiments thereof. FIG. 1A shows an action of a grand piano, according to an embodiment of the present invention. The action 1 operates in accordance with depression of a key 2 to cause a hammer 3 to pivotally move upward, and when the hammer 3 strikes a string S, a piano tone is generated.

[0022] As shown in FIG. 1A, the action 1 is disposed rearward (leftward as viewed in FIG. 1A) of a pivot (not shown) of the key 2 extending in the front-rear direction (left-right direction as viewed in FIG. 1A) and above the key 2, and is comprised of a wippen 4 pivotally movable about a rear end (left end as viewed in FIG. 1A) thereof, a repetition lever 5 and a jack 6 each pivotally attached to the wippen 4, and a repetition spring 7 for urging the two component parts 5 and 6 in a returning direction (counterclockwise direction as viewed in FIG. 1A). Further, a drop screw 8 and a regulating button 9 for restricting upward movements of the respective repetition lever 5 and the jack 6 are provided on an action-by-action basis.

[0023] The action 1 is disposed between brackets 11 and (only one of which is shown in FIG. 1A) provided respectively at left and right ends of a keyframe (not shown) on which the key 2 is placed. Between the left and right brackets 11 and 11, a wippen rail 12 extends in the left-right direction, and the rear end of the wippen 4 is pivotally mounted to a wippen flange 13 fastened to the wippen rail 12 with a screw.

[0024] The wippen 4 is formed by a molded article of a synthetic resin, such as an ABS resin, which is excellent in impact resistance. The wippen 4 includes a body portion 21 extending in the front-rear direction, a lever flange portion 22 extending upward a predetermined length from a central portion of the body portion 21, a heel portion 23 protruding downward from the central portion of the body portion 21, and a support portion 24 for supporting a jack button 26 of a jack angular position-adjusting mechanism 20, described hereinafter. The wippen 4 is placed on a capstan screw 2a of the key 2 via the heel portion 23. Further, in the wippen 4, a front end portion of the body portion 21 and an upper half portion of the lever flange portion 22 are each formed in a bifurcated shape having left and right prongs.

[0025] The repetition lever 5 extends obliquely forward and upward in the front-rear direction and has a central portion thereof pivotally mounted inside upper ends of the lever flange portion 22 of the wippen 4. At a predetermined location in a front portion of the repetition lever 5, there is formed a jack guide hole 5a vertically extending therethrough and extending a predetermined length in the front-rear direction.

[0026] The jack 6 has an L shape, in side view, which is formed by a base portion 6a, a hammer push-up portion 6b extending upward from the base portion 6a, and a regulating button abutment portion 6c extending forward from the base portion 6a, and has its base portion 6a pivotally mounted inside front ends of the body portion 21 of the wippen 4. An upper end of the hammer push-up portion 6b is engaged in the jack guide hole 5a of the repetition lever 5 in a state inserted from below such that the upper end is movable in the front-rear direction. In a key-released state, the upper end of the hammer push-up portion 6b is opposed to a shank roller 33, referred to hereinafter, of the hammer 3 with a slight space therebetween. Further, the hammer push-up portion 6b is formed with an operation hole 6d through which a predetermined tool T (see FIG. 4A) can be inserted so as to operate an adjustment screw 25, referred to hereinafter, of the jack angular position-adjusting mechanism 20 from the front side.

[0027] Further, the wippen 4 is provided with the jack angular position-adjusting mechanism 20 for adjusting an angular position of the jack 6. The jack angular position-adjusting mechanism 20 is comprised of the support portion 24 integrally formed with the wippen 4, the adjustment screw 25 screwed in the support portion 24 such that the adjustment screw 25 is movable forward and backward in the front-rear direction, and the jack button 26 which is provided at a front end of the adjustment screw 25 and is in abutment with the hammer push-up portion 6b of the jack 6.

[0028] As shown in FIG. 1B, the support portion 24 is comprised of a pair of left and right extension portions 24a and 24a extending a predetermined length in parallel with each other from front surfaces of the respective prongs of the lever flange portion 22 toward the jack 6, and an adjustment screw-engaging portion 24b formed in a plate shape having a predetermined thickness and continuous with front ends of the extension portions 24a and 24a. The adjustment screw-engaging portion 24b is formed in a rectangular shape as viewed from the jack side and has a screw hole formed through a central portion thereof.

[0029] FIG. 2 shows the adjustment screw 25 and the jack button 26. As shown in FIG. 2, the adjustment screw 25 is formed by a metal rod having a predetermined diameter and a predetermined length, and has a front end thereof formed with an operation portion 25a formed in a flat shape. The operation portion 25a is operated for turning the adjustment screw 25. Further, the jack button 26 is fixed to the end of the adjustment screw 25 in a state covering the operation portion 25a, and a portion of the adjustment screw 25 rearward of the jack button 26 is formed with a male screw that screws into the screw hole of adjustment screw-engaging portion 24b.

[0030] The jack button 26 is comprised of a button body portion 26a mounted to the adjustment screw 25 in a state having the adjustment screw 25 inserted therethrough and a cylindrical cushion portion 26b bonded to a front surface of the button body portion 26a. The button body portion 26a is made of a predetermined synthetic resin (e.g. an ABS resin) and is formed in a cylindrical shape having a predetermined outer diameter and a predetermined length. On the other hand, the cushion portion 26b is made of e.g. felt and formed in a thick cylindrical shape. The cushion portion 26b has the same outer diameter as that of the button body portion 26a and an inner diameter larger than a length of the operation portion 25a of the adjustment screw 25 in a diametrical direction.

[0031] Further, the cushion portion 26b is formed to have an axial length longer than the axial length of the operation portion 25a of the adjustment screw 25. Therefore, in a state where the jack button 26 is in abutment with the hammer push-up portion 6b of the jack 6, only the cushion portion 26b is in contact with the hammer push-up portion 6b, and the operation portion 25a of the adjustment screw 25 is prevented from being brought into contact with the same. In this case, as shown in FIG. 3, the operation portion 25a of the adjustment screw 25 faces forward via the operation hole 6d of the hammer push-up portion 6b, so that the adjustment screw 25 can be turned using the tool T from the front side of the jack 6, as will be described below.

[0032] Now, a brief description will be given, with reference to FIGS. 4A and 4B, of how to adjust the angular position of the jack by turning the adjustment screw 25. For this adjustment, for example, the tool T having a slit portion Ts that can be engaged with the operation portion 25a of the adjustment screw 25 is used as illustrated in FIG. 4A. First, the slit portion Ts of the tool T is inserted into the operation hole 6d from the front of the jack 6 so as to be engaged with the operation portion 25a of the adjustment screw 25. Then, the tool T is turned to thereby turn the adjustment screw 25 such that the adjustment screw 25 moves forward or backward in the front-rear direction with respect to the adjustment screw-engaging portion 24b.

[0033] FIG. 4B shows a state where the adjustment screw 25 has been screwed into the adjustment screw-engaging portion 24b whereby the jack button 26 has been moved slightly rearward. In this case, the jack 6 has slightly pivotally moved counterclockwise from the FIG. 4A state before the adjustment, whereby the hammer push-up portion 6b is adjusted to a position where the same can properly push up the shank roller 33, referred to hereinafter, of the hammer 3.

[0034] As shown in FIG. 1A, the hammer 3 includes a hammer shank 31 extending in the front-rear direction, a hammer head 32 mounted to a tip end (rear end) of the hammer shank 31, and the shank roller 33 attached to the hammer shank 31 at a predetermined location in a front portion of the lower surface of the same. The hammer 3 has a base end portion of the hammer shank 31 thereof pivotally mounted to a hammer shank flange 35 fastened to a hammer shank rail 34 with screws. The shank roller 33 has a cylindrical shape formed e.g. by a cloth provided inside and a skin wound around the outer periphery of the cloth, and is placed on the upper surface of the repetition lever 5 at a location close to the jack guide hole 5a in a state straddling the jack guide hole 5a.

[0035] Next, a description will be given, with reference to FIGS. 1A and 1B, of the operation of the action 1 constructed as above. When the key 2 is depressed in the key-released state shown in FIG. 1A, the wippen 4 is pushed up via the capstan screw 2a to pivotally move upward, and the repetition lever 5 and the jack 6 also move upward along with the wippen 4. As a consequence of the movement of these, first, the repetition lever 5 pushes up the hammer 3 via the shank roller 33 in a state held in sliding contact with the shank roller 33, to thereby cause the hammer 3 to pivotally move upward. Then, when the repetition lever 5 is brought into abutment with the drop screw 8 from below and has its upward pivotal motion stopped, the jack 6 pushes up the hammer 3 via the shank roller 33. Thereafter, when the hammer 3 is pivotally moved immediately close to a position for striking a string S horizontally stretched above, the jack 6 is brought into abutment with the regulating button 9 via the regulating button abutment portion 6c to have its pivotal motion stopped, whereby the jack 6 leaves the shank roller 33. This releases the hammer 3 from connection with the action 1 and the key 2 to strike the string 3 in a free rotation state.

[0036] Further, when the key 2 is released after the hammer 3 has struck the string 3, the hammer 3 and the wippen 4 are pivotally returned by their own weights and the repetition lever 5 and the jack 6 are pivotally returned by the spring force of the repetition spring 7, in respective opposite directions to the directions in which they are pivotally moved when the key 2 is depressed. Further, in this case, the jack 6 comes into abutment with the jack button 26 of the jack angular position-adjusting mechanism 20 whereby it returns to the key-released state.

[0037] As described above in detail, according to the present embodiment, the jack angular position-adjusting mechanism 20 is provided in the wippen 4, and the jack 6 itself is not provided with an adjustment mechanism for adjusting the angular position of the jack 6, so that it is possible to maintain reduced weight of the jack 6. Further, by turning the adjustment screw 25 screwed in the support portion 24 provided on the wippen 4, the jack button 26 is moved forward or rearward in unison with the adjustment screw 25 in the front-rear direction, whereby the angular position of the jack 6 in abutment with the jack button 26 can be adjusted with ease. Furthermore, in the jack angular position-adjusting mechanism 20, the support portion 24 in which the adjustment screw 25 is screwed is integrally formed with the wippen 4, and hence it is possible to further reduce the weight of the entire wippen 4 compared with the conventional action. As described above, according to the present embodiment, it is possible to reduce not only the weight of jack 6, but also that of the wippen 4, to thereby improve string striking repeatability.

[0038] Note that the present invention is not limited to the above-described embodiment, but it can be practiced in various forms. Further, details of the construction of each of the action 1, the wippen 4, the repetition lever 5, the jack 6, and the jack angular position-adjusting mechanism 20 in the embodiment are described only by way of example, and they can be changed, as desired, within the scope of the subject matter of the present invention.