JP2013125235A - Hammer device of electronic keyboard instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hammer device of an electronic keyboard instrument capable of reducing a manhour in manufacturing, reducing the manufacturing cost, and improving workability in maintenance.SOLUTION: The hammer device of an electronic piano having a key swinging along with depression of the key includes: a hammer support consisting of a synthetic resin and having a support shaft 21; and a hammer 5 having a shaft hole part 24 fitted around the support shaft 21, and rotationally turning about the support shaft 21 in conjunction with the swinging key. The outer peripheral face of the support shaft 21 includes: a pair of curved surface parts 21a formed into an arcuate shape and facing each other; and a pair of plane parts 21b extending between the pair of curved surfaces 21a respectively and being parallel to each other. The hammer 5 rotationally turns in a state where a shaft hole 24a of the shaft hole part 24 comes into surface contact with the pair of curved surface parts 21a of the support shaft 21.

Description

  The present invention relates to a hammer device for an electronic keyboard instrument used for an electronic keyboard instrument such as an electronic piano.

  2. Description of the Related Art Conventionally, as a hammer device for an electronic keyboard instrument, for example, a device described in Patent Document 1 is known. This electronic keyboard instrument includes a chassis, a plurality of keys swingably provided on the chassis, a whippen provided for each key, a center rail to which a hammer device is attached, and the like. The hammer device includes a plurality of hammers, and each of the plurality of hammers is made of a synthetic resin. Each hammer is disposed so as to correspond to each of the plurality of keys, and a rotating shaft is integrally formed at the front end portion of each hammer.

  On the other hand, the center rail includes a bearing member and a bearing member fixing plate, and a U-shaped hole is formed in the bearing member. The bearing member fixing plate is screwed to the bearing member with the rotation shaft 51 of the hammer fitted in the hole of the bearing member, so that the hammer is rotated by the bearing member and the bearing member fixing plate. The shaft 51 is supported so as to be rotatable. In this electronic keyboard instrument, when any one of a plurality of keys is depressed, the whippen corresponding to the depressed key is rotated, and the hammer is rotated in conjunction with the rotation of the whippen. It is configured.

Japanese Patent No. 3270693

  According to the hammer device of the electronic keyboard instrument of Patent Document 1, since the hammer is made of synthetic resin, when the hammer is manufactured by, for example, an injection molding method, as shown in FIG. It is necessary to use two molds B1 and B2 so that the center of the axis A1 is located on the parting line (parting line). There is a risk of occurrence at the left and right ends of the outer peripheral surface.

  If such a parting line mark or burr is left with a hammer left behind, it will interfere with the peripheral surface of the hole in the bearing member when the hammer rotates, hindering the smooth rotation of the hammer. End up. For this reason, when the hammer is manufactured, cutting work is required to remove parting line marks and burrs, which leads to an increase in man-hours and an increase in manufacturing cost.

  Further, in the case of the hammer device of Patent Document 1, since the hammer is supported by the bearing member and the bearing member fixing plate screwed to the bearing member, when the hammer is detached from the center rail during maintenance or the like, It is necessary to perform the attaching / detaching operation, resulting in a problem that workability is low.

  The present invention has been made to solve the above problems, and provides a hammer device for an electronic keyboard instrument that can reduce man-hours during manufacturing, reduce manufacturing costs, and improve workability during maintenance. The purpose is to do.

  In order to achieve the above object, the invention according to claim 1 is a hammer device for an electronic keyboard instrument having a key that swings when the key is pressed, and is composed of a synthetic resin and has a fulcrum shaft. And a hammer that has a fitting portion that fits to the fulcrum shaft, interlocks with the rocking key, and rotates about the fulcrum shaft. The outer peripheral surface of the fulcrum shaft is formed in an arc shape. The hammer is configured by a pair of curved surface portions facing each other and a pair of flat surface portions extending between the pair of curved surface portions and parallel to each other. The hammer has a fitting portion that faces the pair of curved surface portions of the fulcrum shaft. It is comprised so that it may rotate in the state which contacted.

  According to the hammer device of the electronic keyboard instrument, the hammer support portion has the fulcrum shaft, and the outer peripheral surface of the fulcrum shaft is formed in an arc shape, and the pair of curved portions and the pair of curved portions facing each other. It is comprised by a pair of plane part respectively extended between and parallel to each other. The hammer has a fitting portion that fits on the fulcrum shaft, and rotates around the fulcrum shaft in conjunction with the rocking key. In this case, since the hammer support portion is made of a synthetic resin, when the hammer support portion is manufactured by a technique using a mold such as an injection molding method, the mold parting line is a pair of fulcrum shafts. If it is set so that it passes through the boundary between one of the curved surface portions and one of the pair of flat surface portions and the boundary between the other of the pair of curved surface portions and the other of the pair of flat surface portions (see FIG. 5), etc. Even if this occurs, the occurrence location can be set at two locations at the boundary between the curved surface portion and the flat surface portion. Further, since the hammer is configured to rotate in a state where the fitting portion is in surface contact with the pair of curved surfaces of the fulcrum shaft, even if a parting line mark or the like is generated on the fulcrum shaft, During the rotation, the parting line trace is elastically deformed so as to escape to the flat portion side, and does not hinder the smooth rotation of the hammer. Thereby, the cutting process for removing parting line marks and the like is not required, so that the number of man-hours for manufacturing can be reduced and the manufacturing cost can be reduced.

  According to a second aspect of the present invention, in the hammer device for an electronic keyboard instrument according to the first aspect, the fitting portion has an arcuate inner peripheral surface, and has a shaft hole that opens upward, and a fulcrum. The pair of curved surface portions of the shaft are respectively arranged on the upper side and the lower side of the shaft center of the fulcrum shaft, and are fitted in the shaft holes of the fitting portion. It is shorter than the interval between the vertices of the curved surface portion and longer than the interval between the pair of plane portions, and the hammer has an abutting portion that abuts against the upper surface of the key, and the key swings In some cases, the contact portion is configured to rotate about a fulcrum shaft by being pushed upward by a key.

  According to the hammer device of this electronic keyboard instrument, the fitting portion has an arc-shaped inner peripheral surface and has a shaft hole that opens upward, and the pair of curved surface portions of the fulcrum shaft are respectively fulcrum shafts. It is arrange | positioned at the upper side and the lower side of this shaft center, and is fitted in the shaft hole of the fitting part. And since the width of the opening of the shaft hole of the fitting portion is set to be shorter than the interval between the vertices of the pair of curved surface portions and longer than the interval between the pair of flat surface portions, By rotating the hammer so that one curved surface portion is located at the opening portion of the shaft hole, the hammer can be removed from the hammer support portion by moving downward, and by the reverse operation to the above The hammer can be attached to the hammer support. That is, the hammer can be attached to and detached from the hammer support portion by simply turning the hammer by hand without executing the screw attaching / detaching operation, and the workability during maintenance can be improved. In addition, the hammer has an abutting portion that abuts against the upper surface of the key, and when the key swings, the abutting portion is pushed upward by the key to rotate around the fulcrum shaft. Since it is configured to move, the upward force acting on the fulcrum shaft can be appropriately supported by the lower curved surface portion of the fulcrum shaft when the key starts to swing.

1 is a side view showing a configuration around a keyboard of a hammer device according to an embodiment of the present invention and an electronic keyboard instrument to which the hammer device is applied, with a part thereof broken; (A) The perspective view which shows the structure of the hammer support for 1 octave, (b) The perspective view which shows the structure of the state which fractured | ruptured a part of hammer support. It is a top view which shows the structure of a hammer support. It is a figure which shows the cross-sectional shape of the fulcrum shaft of a hammer support. It is sectional drawing which shows the positional relationship of the parting line of a metal mold | die, and a fulcrum axis | shaft in the case of manufacturing a hammer support by the injection molding method. It is the (a) top view and (b) side view which show the structure of a hammer. (A) The figure for demonstrating operation | movement of the hammer at the time of key pressing, (b) The figure for demonstrating the operation | movement at the time of removing a hammer. (A) It is a figure which shows the state in which a hammer exists in an origin position for demonstrating operation | movement of a hammer, (b) It is a figure which shows a state when a hammer rotates to a rotation limit position. It is sectional drawing which shows the positional relationship of the parting line of a metal mold | die, and a rotating shaft when manufacturing the rotating shaft in the hammer apparatus of patent document 1 by the injection molding method.

  Hereinafter, a hammer device for an electronic keyboard instrument according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the hammer device 1 is applied to an electronic piano P as an electronic keyboard instrument, and the electronic piano P includes a keyboard device.

  This keyboard device includes a large number of keys 2 (only one white key 2a and one black key 2b are shown) arranged in the horizontal direction of the electronic piano P (the front and back sides in FIG. 1), and a keyboard that supports these keys 2. A chassis 3, a hammer support 4 connected to the rear end portion (right end portion in FIG. 1) of the keyboard chassis 3, and a plurality of keys provided for each key 2 and rotating in conjunction with the pressed key 2. A hammer 5 (only one shown), a number of let-off components 6 (only one shown) provided for each hammer 5 to give a let-off feeling when the key 2 is pressed, and key pressing information of the key 2 The key switch 7 is used for detection.

  The keyboard chassis 3 is composed of three support rails 9 including a front rail 9a, a middle rail 9b, and a rear rail 9c extending in the left-right direction, and five reinforcing ribs 10 extending in the front-rear direction, in a cross-beam shape. It is fixed on a shelf board (not shown). Each of these support rails 9 and ribs 10 is composed of an iron plate formed into a predetermined shape by stamping and bending with a press. The plate thickness of the support rail 9 is set to be thinner (for example, 1.0 mm) for weight reduction, and the plate thickness of the rib 10 is set to be thicker (for example, 1.6 mm) for reinforcement.

  A saddle front 11 and a saddle center 12 are fixed to the lower surface of the front rail 9a and the upper surface of the middle rail 9b, respectively. The saddle front 11 and the saddle center 12 are thick plate-shaped members made of synthetic resin, and extend in the left-right direction over the entire front rail 9a and middle rail 9b. A large number of balance pins 13 are erected in a state where the balance 12 is arranged in the left-right direction at the front and rear positions corresponding to the white key 2a and the black key 2b. A large number of front pins 14 are erected on the front 11 in front and rear positions corresponding to the white key 2a and the black key 2b in a state where the front pins 14 are arranged in the left-right direction.

  The key 2 includes a wooden key body 15 extending in the front-rear direction and having a rectangular cross section, and a key cover 16 made of synthetic resin bonded to the upper surface and the front surface of the front portion. A balance pin hole 17 is formed behind the center of the key body 15, and the key 2 is swingably supported by the balance pin 13 through the balance pin hole 17. Further, a front pin hole 18 is formed at the front end portion of the key body 15, and the front pin hole 18 engages with the front pin 14, thereby causing a lateral shake when the key 2 rotates. Is prevented.

  The hammer support 4 is formed by connecting resin molded products for one octave to each other, extends in the left-right direction so as to cover all the hammers 5, and is screwed to the rear rail 9 c of the keyboard chassis 3. The hammer support 4 is composed of a hammer support portion 19 standing upright from the vicinity of the rail 9c and a switch mounting portion 20 extending obliquely upward from the upper end portion. A horizontal pin-shaped fulcrum shaft 21 for supporting each hammer 5 is formed at the upper end portion of the hammer support portion 19.

  The hammer 5 has an arm-shaped hammer body 22 extending in the front-rear direction and a weight plate 23 (only one is shown) attached to the front end portions of the left and right side surfaces thereof. The hammer body 22 is made of a synthetic resin, and the weight plate 23 is made of a metal material such as iron having a relatively large specific gravity. A rear end portion of the hammer body 22 is a shaft hole portion 24, and an arc-shaped shaft hole 24 a (see FIGS. 6 and 8) is formed in the shaft hole portion 24. The hammer 5 is rotatably supported by the hammer support 4 by being fitted to the fulcrum shaft 21 through the shaft hole 24 a of the shaft hole portion 24.

  Further, a capstan screw 25 is screwed into the lower surface of the hammer body 22 at a position immediately in front of the shaft hole portion 24 so as to freely advance and retract. The hammer 5 is placed on the rear end portion of the key 2 via the capstan screw 25. Further, a portion between the shaft hole portion 24 and the capstan screw 25 on the upper surface of the hammer body 22 is an actuator portion 26 for operating the key switch 7 when the key is depressed. Furthermore, a plate-like engagement protrusion 27 that engages with the let-off component 6 when a key is pressed is provided at the center of the upper surface of the hammer body 22 in the front-rear direction.

  The let-off component 6 is formed of a molded product of a predetermined elastic material (for example, a styrene-based thermoplastic elastomer) and is attached to the switch attachment portion 20 of the hammer support 4. The let-off component 6 obliquely extends rearward and downward from the switch mounting portion 20, and a head portion 28 is formed at a tip portion thereof via a constricted portion. The head portion 28 faces the engaging protrusion 27 of the hammer 5 in the key release state.

  The key switch 7 includes a switch board 29 made of a printed circuit board and a switch body 30 made of a rubber switch provided for each key 2 on the lower surface of the switch board 29. The switch board 29 has a rear end portion inserted into the switch mounting portion 20 and a front end portion and a central portion screwed to the switch mounting portion 20. In addition, the switch body 30 faces the actuator portion 26 of the hammer 5 with a slight gap in the key release state. Furthermore, a hammer stopper 31 made of foamed urethane or the like that restricts the upward rotation of the hammer 5 is provided at the front end of the lower surface of the switch mounting portion 20.

  Next, the operation of the above keyboard device will be described. When the key 2 is pressed from the key release state shown in FIG. 1, the key 2 rotates about the balance pin 13 in the counterclockwise direction in FIG. 1, and accordingly, the hammer 5 moves the capstan screw 25. And pivoted about the fulcrum shaft 21 in the clockwise direction in FIG.

  During the rotation of the hammer 5, the engaging projection 27 engages with the head 28 of the let-off component 6 and presses the let-off component 6 while compressing the let-off component 6 through the head 28. The reaction force acting on the hammer 5 increases. As the rotation of the hammer 5 progresses, the engagement protrusion 27 is disengaged from the head 28, so that the reaction force from the let-off component 6 disappears rapidly. Due to the increase and disappearance of the reaction force of the let-off component 6, a let-off feeling similar to that of an acoustic piano can be obtained.

  Thereafter, the hammer 5 comes into contact with the hammer stopper 31 to complete the upward rotation of the hammer 5. During the upward rotation of the hammer 5, the actuator portion 26 presses the switch body 30 of the key switch 7 and turns on the key switch 7, thereby pressing the key 2 according to the rotation amount of the hammer 5. Key information is detected and output to a sound generation control device (not shown). The sound generation control device controls the sound generation of the electronic piano based on the detected key press information.

  After that, when the key 2 is released, the key 2 rotates in the opposite direction to that when the key is pressed, and returns to the key release state shown in FIG. 1, and the hammer 5 is also rotated downward and released. Return to the key state.

  Next, the hammer device 1 according to the present embodiment will be described in detail with reference to the example for the white key 2a with reference to FIGS. The hammer device 1 includes the hammer support 4 and the hammer 5 described above. The hammer support 4 is made of a synthetic resin, and a resin molded product for one octave shown in FIGS. 2A and 3 is manufactured by an injection molding method.

  The hammer support 4 has a plurality of partition walls 51 that partition adjacent hammers 5 in a state where they are spaced apart from each other in the left-right direction, and the fulcrum described above is provided between the adjacent partition walls 51, 51. The shaft 21 extends in the left-right direction. As shown in FIG. 4, the fulcrum shaft 21 has a so-called oval cross-sectional shape in which two portions of a circle centered on the axis of the fulcrum shaft 21 are cut out. The outer peripheral surface of the fulcrum shaft 21 includes a pair of curved surface portions 21a and 21a and a pair of flat surface portions 21b and 21b extending between the pair of curved surfaces 21a and 21a.

  The pair of curved surface portions 21 a and 21 a face each other and are arranged symmetrically with respect to the axis of the fulcrum shaft 21, and the pair of plane portions 21 b and 21 b are parallel to each other and on the axis of the fulcrum shaft 21. They are arranged symmetrically with respect to the point. With the above configuration, in this fulcrum shaft 21, the distance L1 between the vertices of the pair of curved surface portions 21a, 21a is set to a value larger than the distance L2 between the pair of flat surface portions 21b, 21b.

  Further, when the hammer support 4 is manufactured, as shown in FIG. 5, two molds 100 and 101 are used for the portion of the fulcrum shaft 21, and both parting lines have four curved surfaces. Of the boundary between the portion 21a and the flat portion 21b (hereinafter referred to as “boundary portion”), it coincides with two boundary portions (hereinafter referred to as “line boundary portions”) facing each other with the axis of the fulcrum shaft 21 therebetween. Is set as follows. The reason for this will be described later.

  On the other hand, the hammer 5 is for the white key 2a. As shown in FIGS. 6 (a) and 6 (b), the hammer body 22 is basically symmetrical and has a front end. The portion is a plate-like weight attaching portion 41 having a relatively thin predetermined thickness, and plate-like weight plates 23 and 23 are riveted to the left and right side surfaces of the weight attaching portion 41. .

  Further, the shaft hole 24a of the shaft hole portion 24 of the hammer body 22 is formed in a C-shape with an inner peripheral surface having an arc shape and a side surface opening upward. In the case of this shaft hole 24a, the width L3 of the opening (see FIG. 6B) is slightly smaller than the distance L1 between the vertices of the curved surface portions 21a and 21a and is smaller than the distance L2 between the flat surface portions 21b and 21b. The diameter of the arc on the inner peripheral surface is set slightly larger than the distance L1 between the vertices of the curved surface portions 21a and 21a. With the above configuration, the hammer 5 can be attached to and detached from the fulcrum shaft 21 through the opening of the shaft hole 24 a of the hammer body 22.

  Further, the hammer 5 is held at the origin position indicated by a solid line in FIG. 7A in the key-released state, and in this state, as shown in FIGS. 7A and 8A, the fulcrum shaft 21 is held. Is held in a state in which a part of the upper curved surface portion 21a and the entire lower curved surface portion 21a are in surface contact with the inner peripheral surface of the shaft hole 24a. When the key is depressed, the hammer 5 is rotated from the origin position to the rotation limit position indicated by a two-dot chain line in FIG. 7A and then returned to the origin position. At this time, in a state where the hammer 5 is at the rotation limit position, as shown by a solid line in FIG. 8B, the fulcrum shaft 21 is formed by a part of the upper curved surface portion 21a and the lower curved surface portion 21a. Is held in surface contact with the inner peripheral surface of the shaft hole 24a. With the above configuration, the hammer 5 is held in a retaining state with respect to the fulcrum shaft 21 during both rotation and stop.

  On the other hand, when the hammer 5 is removed from the hammer support 4, the hammer 5 is removed from the keyboard device after the key 5 on which the hammer 5 is placed via the capstan screw 25 is removed. From the origin position indicated by the two-dot chain line to the removal position indicated by the solid line in FIG. Accordingly, the hammer 5 has a posture in which the opening portion of the shaft hole 24a faces upward. Therefore, the hammer 5 can be detached from the fulcrum shaft 21 by moving the shaft hole portion 24 of the hammer 5 downward. .

  As described above in detail, according to the hammer device 1 of the present embodiment, the hammer 5 rotates about the fulcrum shaft 21 of the hammer support 4, and the outer peripheral surface of the fulcrum shaft 21 is a pair of curved surface portions 21a. , 21a and a pair of flat portions 21b, 21b. In this case, as described above, when the hammer support 4 is manufactured by the injection molding method, the parting lines of the two molds 100 and 101 are set so as to coincide with the boundary between the two lines. Even if a parting line mark is generated on the shaft 21, the generated part is a boundary between two lines. The hammer 5 rotates in a state where the inner peripheral surface of the shaft hole 24a is in surface contact with the curved surface portions 21a, 21a. Therefore, during the rotation of the hammer 5, the parting line trace on the two line boundary portions is The elastic deformation is performed so as to escape to the flat portion 21b side, and the smooth rotation of the hammer 5 is not hindered. Thereby, the cutting process for removing parting line marks and the like is not required, so that the number of man-hours for manufacturing can be reduced and the manufacturing cost can be reduced.

  Further, the width L3 of the opening of the shaft hole 24a is set to be slightly smaller than the interval L1 between the apexes of the curved surface portions 21a and 21a and slightly larger than the interval L2 between the plane portions 21b and 21b. The diameter of the circular arc on the peripheral surface is set slightly larger than the distance L1 between the vertices of the curved surface portions 21a and 21a. Therefore, after removing the key 2 during maintenance, the operator rotates the hammer 5 so that the center of one curved surface portion 21a is at the center of the opening of the shaft hole 24a, and then moves the hammer 5 downward. The hammer 5 can be removed from the hammer support 4, and the hammer 5 can be attached to the hammer support 4 by the reverse operation. In other words, the hammer 5 can be attached to and detached from the hammer support 4 by simply turning the hammer 5 by hand without executing the screw attaching / detaching operation, and the workability during maintenance can be improved.

  In addition, the hammer 5 is in contact with the upper surface of the key 2 via the capstan screw 25, and the capstan screw 25 is pushed upward by the key 2 when the key 2 swings by the key depression. Therefore, when the key 2 starts to swing, the upward force acting on the fulcrum shaft 21 is appropriately applied to the entire curved surface portion 21a below the fulcrum shaft 21. Can support you.

  As is apparent from FIG. 8, one of the four boundary portions is configured to be located in the opening of the shaft hole 24a both when the hammer 5 is stopped and during rotation. Therefore, when this one boundary portion is set as a line boundary portion, only one of the parting line traces on the two line boundary portions is rotated during the rotation of the hammer 5 in the shaft hole 24a. It will be in contact with the inner peripheral surface. Thereby, the hammer 5 can be rotated more smoothly.

  The embodiment is an example in which the hammer device is applied to an electronic piano as an electronic keyboard instrument. However, the electronic keyboard instrument to which the hammer device of the present invention is applied is not limited to this, and a key that swings by pressing a key is used. Anything provided is sufficient. For example, the hammer device of the present invention may be applied to an organ type electronic keyboard instrument.

P Electronic piano (electronic keyboard instrument)
1 Hammer device 2 Key 4 Hammer support (Hammer support)
5 hammer 21 fulcrum shaft 21a curved surface portion 21b flat surface portion 24 shaft hole portion (fitting portion)
24a Shaft hole 25 Capstan screw (contact part)
L1 Spacing between a pair of curved surface portions L2 Spacing between a pair of flat surface portions L3 Width of shaft hole opening

Claims (2)

A hammer device for an electronic keyboard instrument having a key that swings as the key is pressed,
A hammer support made of synthetic resin and having a fulcrum shaft;
A hammer having a fitting portion fitted to the fulcrum shaft, interlocked with the rocking key, and rotated around the fulcrum shaft;
With
The outer peripheral surface of the fulcrum shaft is
A pair of curved surface portions formed in an arc shape and facing each other;
It extends between the pair of curved surface portions, and is composed of a pair of plane portions parallel to each other.
The hammer device for an electronic keyboard instrument, wherein the hammer is configured to rotate in a state where the fitting portion is in surface contact with the pair of curved surface portions of the fulcrum shaft. The fitting portion has an arcuate inner peripheral surface, and has a shaft hole that opens upward,
The pair of curved surface portions of the fulcrum shaft are respectively disposed on the upper side and the lower side of the shaft center of the fulcrum shaft, and are fitted in the shaft hole of the fitting portion
The width of the opening of the shaft hole of the fitting portion is set shorter than the interval between the vertices of the pair of curved surface portions and longer than the interval between the pair of plane portions,
The hammer has an abutting portion that abuts on the upper surface of the key, and when the key swings, the abutting portion is pushed upward by the key, thereby centering on the fulcrum shaft. The hammer device for an electronic keyboard instrument according to claim 1, wherein the hammer device is configured to rotate.

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