JP2013076817A - Method for manufacturing hammer of electronic keyboard instrument, and hammer of electronic keyboard instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a hammer of an electronic keyboard instrument, which allows fine adjustment of the position of the center of gravity of a hammer and can provide a good touch feeling, and a hammer of an electronic keyboard instrument.SOLUTION: A hammer is manufactured which includes: an arm-shaped hammer body which has a plurality of recesses juxtaposed on a side surface thereof in a lengthwise direction of the side surface and is made of a synthetic resin; and a weight plate attached to the hammer body. First to third nests 60a to 60c having shapes complementary to the plurality of recesses of the hammer body are attached to at least one of a fixed die plate and a movable die plate so as to freely move forward and backward relative to cavities 58a and 58b, and a molten synthetic resin is injected to the cavities 58a and 58b in a state where forward/backward movement positions of the nests 60a to 60c relative to the cavities 58a and 58b are adjusted independently of one another, whereby the hammer body is molded.

Description

  The present invention relates to a method for manufacturing a hammer for an electronic keyboard instrument that is used in an electronic keyboard instrument such as an electronic piano and rotates in conjunction with a pressed key, and a hammer for an electronic keyboard instrument.

  As a conventional hammer of an electronic keyboard instrument, for example, a hammer disclosed in Patent Document 1 is known. This hammer is composed of a resin portion and a metal rod as a mass body, and is rotatably attached to a support member via the resin portion. The metal bar is made of iron or the like, is formed integrally with the resin portion by outsert molding, and extends from the resin portion so as to be away from the fulcrum of the hammer. The tip portion of the metal bar is folded back, and the turning portion increases the mass of the tip portion of the metal rod, thereby increasing the rotational moment of the hammer. Further, by changing the length and angle of the folded portion for each key or for each predetermined sound range by cutting or bending the metal bar, a touch feeling corresponding to the key or the sound range is obtained.

Japanese Patent No. 2917863

  For example, in a grand piano, the weight of the hammer and the position of the center of gravity differ for each key. Specifically, the lower the sound side, the heavier the hammer and the farther the center of gravity position is from the fulcrum, and a touch feeling corresponding to the difference can be obtained. Therefore, in order to obtain a good touch feeling similar to that of a grand piano in an electronic keyboard instrument such as an electronic piano, it is preferable to change the position of the center of gravity of the hammer according to the key and the sound range.

  On the other hand, in the conventional hammer described above, the position of the center of gravity of the hammer is adjusted by changing the length and angle of the folded portion by cutting or bending the metal rod. However, since the accuracy of both cutting and bending of the metal bar is low, the center of gravity of the hammer can only be roughly adjusted, and fine adjustment cannot be performed. In addition, since the center of gravity of the hammer is adjusted only with a metal bar, the number of metal bars of the same number (type) as the number of adjustment stages, for example, the same number of bars as the key if the center of gravity is adjusted for each key Must be produced, and its production and management become very complicated.

  The present invention has been made to solve the above-described problems, and can adjust the center of gravity of the hammer finely, thereby obtaining a good touch feeling. And to provide an electronic keyboard instrument hammer.

  In order to achieve the above object, the invention according to claim 1 is an arm-shaped hammer body made of a synthetic resin having a plurality of recesses arranged side by side along the length direction thereof, and attached to the hammer body. A method for manufacturing a hammer of an electronic keyboard instrument that rotates in conjunction with a depressed key, each having a cavity that has a shape complementary to the side shape of the hammer body A template and a movable side template are prepared, and a plurality of nestings each having a shape complementary to the plurality of recesses of the hammer body are placed in a predetermined position on at least one of the fixed side template and the movable side template with respect to the cavity. Attached so that it can move forward and backward, and adjusts the position of multiple nestings in relation to the cavity independently of each other. With the fixed mold plate and movable mold plate clamped, melted synthetic resin into the cavity By leaving, characterized by molding the hammer body.

  According to this manufacturing method, a plurality of concave portions corresponding to a plurality of nestings are provided side by side along the length direction of the side surface, having a side shape corresponding to the cavities of the fixed side mold plate and the movable side mold plate. A synthetic resin hammer body is formed. Further, during the molding, the thicknesses of the plurality of recesses are individually changed by independently adjusting the advancing and retreating positions of the plurality of nests with respect to the cavity. In addition, the accuracy of injection molding is much higher than the accuracy of cutting and bending of metal bars that have been used to adjust the center of gravity of a conventional hammer. Therefore, a hammer body having a desired weight and / or center of gravity can be obtained with high accuracy. And by combining the hammer body with weight and / or center of gravity accurately adjusted in this way with the weight, the center of gravity of the entire hammer determined by both is adjusted, so the center of gravity of the hammer can be finely adjusted, Therefore, a good touch feeling can be obtained.

  The invention according to claim 2 is the method of manufacturing the hammer of the electronic keyboard instrument according to claim 1, wherein the adjustment of the advance / retreat position of the plurality of nesting is performed by a plurality of combination patterns having different combinations of the advance / retreat positions. A plurality of types of hammer bodies having different weights and / or center-of-gravity positions are formed.

  According to this configuration, when the hammer body is molded, the advance and retreat positions of the plurality of nestings with respect to the cavity are adjusted by the plurality of combination patterns, respectively, so that the weight and / or the center of gravity according to the combination pattern are adjusted. Multiple types of hammer bodies with different positions can be easily obtained. Then, by selecting a hammer body from these multiple types of hammer bodies according to the sound range or key, it is possible to easily realize an appropriate hammer center of gravity position according to the sound range or key.

  According to a third aspect of the present invention, in the method for manufacturing a hammer for an electronic keyboard instrument according to the second aspect, a plurality of types of weights having different weights are prepared as weights, and the hammers are selected from a plurality of types of hammer bodies. A weight selected from a plurality of types of weights is attached to the main body.

  According to this configuration, a combination of a hammer body selected from a plurality of types of hammer bodies having different weights and / or positions of the center of gravity and a weight selected from a plurality of types of weights having different weights is possible. Different center of gravity positions of the hammers can be realized, so that the center of gravity position of the hammers can be finely adjusted over a wide range. Also, since the center of gravity of the hammer is adjusted by the combination of the hammer body and the weight, the number of parts to be prepared is reduced compared to the conventional case where this adjustment is performed only with a metal rod, By simplifying the management, the position of the center of gravity can be adjusted more easily.

  The invention according to claim 4 is the method of manufacturing a hammer for an electronic keyboard instrument according to claim 3, wherein one type of weight is selected for each of a plurality of predetermined sound ranges, and a plurality of types of weights are selected in each of the plurality of sound ranges. The hammer body is selected.

  According to this configuration, the range of the electronic piano is divided into a plurality of predetermined ranges, and one type of weight having the same weight is selected for each of the divided ranges. Further, a plurality of types of hammer bodies are selected within each sound range. Thereby, the gravity center position of the hammer can be coarsely adjusted for each sound range by a weight having a larger specific gravity, and fine adjustment can be made by the hammer body in each sound range. As a result, for example, it is possible to realize a distribution of the center of gravity position close to the grand piano so that the center of gravity position gradually shifts to the tip side of the hammer as it goes toward the bass side over the entire sound range, and a good touch feeling that is very close to the grand piano Can be obtained.

  The invention according to claim 5 is a hammer for an electronic keyboard instrument, comprising a hammer body manufactured by the method for manufacturing a hammer for an electronic keyboard instrument according to any one of claims 1 to 4.

  According to this configuration, the above-described effects according to claims 1 to 4 can be similarly obtained in the hammer of the electronic keyboard instrument.

It is a side view which shows the keyboard apparatus of the electronic piano provided with the hammer manufactured by the manufacturing method by one Embodiment of this invention in the state which partly notched. It is a perspective view of a hammer It is (a) top view and (b) side view of a hammer. It is a front view which shows roughly the metal mold | die for shape | molding a hammer main body. It is a figure which shows the modeling part of the metal mold | die of FIG. It is a figure which shows the molding condition of the hammer main body by a metal mold | die. It is a figure which shows the shaping | molding condition of the hammer main body different from FIG. 6 by a metal mold | die.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a keyboard device of an electronic piano equipped with a hammer manufactured by the manufacturing method according to the present invention in a key release state.

  As shown in the figure, the keyboard device 1 includes a large number of keys 2 (only one white key 2a and one black key 2b are shown) arranged in the left-right direction (front and back direction in FIG. 1) of the electronic piano, A keyboard chassis 3 that supports the key 2, a hammer support 4 connected to the rear end (right end in FIG. 1) of the keyboard chassis 3, and provided for each key 2. A number of hammers 5 (only one shown), a number of let-off parts 6 (only one shown) provided for each hammer 5 to give a let-off feeling when the key 2 is depressed, and a key The key switch 7 is used to detect the key depression information 2.

  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 at the center of the key body 15 in the front-rear direction, 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 made of a synthetic resin, and is formed by connecting a plurality of molded products for one octave, for example, and extends in the left-right direction so as to cover all the hammers 5, and is attached to the rear rail 9 c of the keyboard chassis 3. It is screwed. 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 portion 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 molded product, and the weight plate 23 is made of a metal material such as iron having a relatively large specific gravity. An arc-shaped shaft hole 24 is formed at the rear end portion of the hammer body 22, and the hammer 5 is rotatable to the hammer support 4 by engaging the shaft hole 24 with the fulcrum shaft portion 21. It is supported.

  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 24 so as to be able to 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 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 extends obliquely backward 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 inserted into the switch mounting portion 20 and is screwed to the switch mounting portion 20 at a central portion. The switch body 30 is attached to the lower surface of the switch substrate 29 and 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 keyboard apparatus 1 having the above configuration 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 pivots upward (clockwise in the figure) around the fulcrum shaft 21.

  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 configuration and manufacturing method of the hammer 5 according to the present invention will be described in detail. As described above, the hammer 5 is composed of a synthetic resin molded product, and is composed of an arm-shaped hammer body 22 extending in the front-rear direction and a metal material, and is attached to the front ends of the left and right side surfaces of the hammer body 22. It consists of a weight plate 23 and the like.

  As shown in FIGS. 2 and 3, the hammer body 22 is basically configured symmetrically and has a predetermined side shape as shown in FIG. The front end portion of the hammer body 22 is a weight plate attachment portion 41, and weight plates 23 and 23 are attached to the left and right side surfaces of the weight plate attachment portion 41 by rivets 42. Although not shown, a plurality of types of weight plates 23 (for example, four types for each of the white key 2a and the black key 2b) are prepared as the weight plate 23. These four types of weight plates 23 are different in size and have different weights. The weight plates 23 are selected for each predetermined sound range, and heavier weight plates 23 are arranged in the lower sound range.

  Further, three concave portions 43 including a front concave portion 43a, a middle concave portion 43b, and a rear concave portion 43c are arranged in parallel along the length direction of the hammer main body 22 in a portion on the rear side of the weight attaching portion 41 of the hammer main body 22. Has been. The front concave portion 43a, the middle concave portion 43b, and the rear concave portion 43c are formed on the left and right side surfaces of the hammer main body 22, and are provided on almost the entire side surface except for the respective peripheral edge portions. The capstan screw 25 described above is provided on the wall of the rear recess 43c.

  Also, as the hammer body 22, a plurality of types (for example, four types) of hammer bodies 22 are prepared. These four types of hammer bodies 22 have different center of gravity positions due to the different thicknesses of the recesses 43. In each of the predetermined sound ranges, the center of gravity position is closer to the tip side as the bass side is increased. A near hammer body 22 is selected and placed.

  As a result of the hammer body 22 and the weight plate 23 being selected and combined as described above, the center of gravity position of the hammer 5 gradually shifts to the tip side of the hammer 5 toward the bass side over the entire sound range of the electronic piano. The distribution is set close to that of a grand piano.

  4 and 5 show a mold for molding the hammer body 22. As shown in FIG. 4, the mold 50 is attached to an upper fixed side mold plate 52 attached to the fixed side attachment plate 51 and a movable side attachment plate 53 via a spacer block 54 and a receiving plate 55. A lower movable side mold plate 56 is provided.

  As shown in FIG. 5, the fixed-side mold plate 52 and the movable-side mold plate 56 are respectively provided with a fixed-side modeling portion 57a and a movable-side modeling portion 57b. Cavities 58a and 58b having shapes complementary to the side surface shape of the hammer body 22 are formed in the fixed side modeling portion 57a and the movable side modeling portion 57b, respectively.

  Further, the fixed side modeling portion 57a and the movable side modeling portion 57b have first to third nestings 60a to 60c at predetermined positions respectively corresponding to the front concave portion 43a, the middle concave portion 43b, and the rear concave portion 43c of the hammer body 22. Is provided. The first to third nestings 60a to 60c on the fixed-side modeling part 57a side and the movable-side modeling part 57b side are arranged symmetrically in the vertical direction and have the same configuration as each other. The thing of the modeling part 57a side is demonstrated.

  The first nest 60a has a shape complementary to the front recess 43a of the hammer body 22, and is accommodated in a recess 61a formed in the fixed-side modeling portion 57a. The recess 61a has a constant cross section having the same shape as the first nesting 60a, and opens on the lower surface of the fixed-side modeling portion 57a. An adjustment screw 62a is screwed on the upper surface of the first insert 60a. The adjustment screw 62a is provided so as not to move in the vertical direction with respect to the fixed-side modeling portion 57a.

  With the above configuration, when the adjustment screw 62a is turned, the first nest 60a moves in the up-down direction within the recess 61a and advances and retreats with respect to the cavity 58a. Further, the advance / retreat position (projection amount) of the first nest 60a with respect to the cavity 58a is adjusted steplessly according to the rotation amount of the adjustment screw 62a.

  The configuration of the second nesting 60b and the third nesting 60c is basically the same as the configuration of the first nesting 60a described above. Specifically, the second nest 60b has a shape complementary to the middle recess 43b of the hammer body 22, is accommodated in the recess 61b of the fixed-side modeling portion 57a, and is provided on the upper surface of the second nest 60b. By turning the non-movable adjusting screw 62b, the adjustment screw 62b moves up and down in the recess 61b and moves forward and backward with respect to the cavity 58a. Further, the advance / retreat position of the second insert 60b with respect to the cavity 58a is adjusted steplessly according to the rotation amount of the adjustment screw 62b.

  Similarly, the third nest 60c has a shape complementary to the rear recess 43c of the hammer body 22, is accommodated in the recess 61c of the fixed-side modeling portion 57a, and is provided on the upper surface of the third nest 60c. By turning the impossible adjustment screw 62c, the adjustment screw 62c moves up and down in the recess 61c and moves forward and backward with respect to the cavity 58a. Further, the advance / retreat position of the third insert 60c with respect to the cavity 58a is adjusted steplessly according to the rotation amount of the adjustment screw 62c.

  When the hammer body 22 is molded using the above-described mold 50, the movable side mold plate 56 is first lowered, and the fixed side mold plate 52 and the movable side mold plate 56 are opened to each other, and the adjustment screws 62a to 62d. Turn 62c to adjust the advance / retreat position of the first to third inserts 60a-60c relative to the cavities 58a, 58b. Next, the movable side mold plate 56 is raised, and the fixed side mold plate 52 and the movable side mold plate 56 are melted from the injection molding machine via a resin injection port (both not shown) while being clamped. The hammer body 22 is molded by injecting and injecting synthetic resin into the cavities 58a and 58b.

  The hammer body 22 molded as described above has a side surface shape corresponding to the cavities 58 a and 58 b of the fixed side mold plate 52 and the movable side mold plate 56. Further, on both the left and right side surfaces of the hammer body 22, a front recess 43a, an intermediate recess 43b and a rear recess 43c corresponding to the first to third inserts 60a to 60c, respectively, are formed. Moreover, the thickness of the front recessed part 43a, the middle recessed part 43b, and the rear recessed part 43c is decided according to the advance / retreat position of the 1st-3rd nesting 60a-60c adjusted with the adjusting screws 62a-62c.

  6 and 7 show two examples in which the hammer main body 22 is formed by changing the advance and retreat positions of the first to third inserts 60a to 60c. FIG. 6 is an example of the hammer main body 22 for the bass side. In this case, the advancing / retreating positions of the first to third inserts 60a to 60c are adjusted so that the amount of protrusion to the cavities 58a and 58b decreases in the order of the first to third inserts 60a to 60c (FIG. )). Therefore, in this case, the thickness of the concave portion 43 increases in the order of the front concave portion 43a, the middle concave portion 43b, and the rear concave portion 43c, and the hammer main body 22 whose center of gravity is close to the distal end side is obtained ((b) in the figure). .

  On the other hand, FIG. 7 is an example of the hammer main body 22 for the high sound side. In this case, the forward and backward positions of the first to third nestings 60a to 60c are set so that the amount of protrusion to the cavities 58a and 58b increases in the order of the first to third nestings 60a to 60c, contrary to the above. Adjust ((a) in the figure). Therefore, in this case, the thickness of the concave portion 43 becomes smaller in the order of the front concave portion 43a, the middle concave portion 43b, and the rear concave portion 43c. A hammer body 22 having substantially the same length is obtained ((b) in the figure).

  Although not shown, in addition to the low-frequency and high-frequency hammer bodies 22 described above, the advance / retreat position of the second nest 60b is the same as described above, and the advance / retreat positions of the first and third nests 60a, 60c are shown in FIG. Two types of hammer main bodies 22 for medium sound are formed in a state adjusted to two positions in the middle of FIG. As described above, a total of four types of hammer bodies 22 are prepared in which the center of gravity is located closer to the tip side and the weight is substantially the lower the bass side. The hammer 5 is configured by selecting and combining the hammer body 22 and the weight plate 23 as described above from the four types of weight plates 23 having different weights from the four types of hammer main bodies 22. The position of the center of gravity of the hammer 5 is adjusted.

  As described above, according to the present embodiment, when the hammer body 22 is injection-molded, the advance and retreat positions of the first to third inserts 60a to 60c are adjusted, and the front recess 43a, the middle recess 43b, and the rear recess 43c are adjusted. Since the thickness is changed steplessly, the hammer body 22 having a desired center of gravity can be obtained with high accuracy. Then, by combining the hammer body 22 with the center of gravity position adjusted with accuracy with the weight plate 23, the center of gravity position of the hammer 5 can be finely adjusted, and thus a good touch feeling can be obtained.

  Further, by adjusting the advance and retreat positions of the first to third inserts 60a to 60c independently of each other by the adjusting screws 62a to 62c, a plurality of types of hammer bodies 22 having different positions of the center of gravity can be easily obtained, and the plurality of these Since the hammer main body 22 is selected from the types of hammer main bodies 22 according to the sound range and the key 2, an appropriate center of gravity position of the hammer 5 according to the sound range and the key 2 can be easily realized.

  Further, since the hammer body 22 and the weight plate 23 selected from a plurality of types of hammer bodies 22 having different positions of the center of gravity and a plurality of types of weight plates 23 having different weights are combined, the position of the center of gravity of the hammer 5 that is different for each combination. Therefore, the position of the center of gravity of the hammer 5 can be finely adjusted over a wide range. Further, since the position of the center of gravity of the hammer 5 is adjusted by the combination of the hammer body 22 and the weight plate 23, the number of parts to be prepared is reduced as compared with the conventional case where this adjustment is performed only with a metal rod, Since the production and management thereof are simplified, the position of the center of gravity of the hammer 5 can be adjusted more easily.

  In addition, for each predetermined sound range, the heavier weight plate 23 is arranged in the lower sound range, and in each sound range, the hammer body 22 whose center of gravity is closer to the tip side is arranged in the lower sound side. The distribution of the center of gravity of the hammer 5 close to the grand piano can be realized so that the center of gravity gradually shifts toward the tip side of the hammer 5 toward the bass side over the entire sound range, and a good touch feeling similar to a grand piano can be realized. Can be obtained.

  Further, the present invention adjusts the advance / retreat positions of the plurality of nestings independently of each other and individually changes the thickness of the recesses. The present invention can be implemented in various modes other than the embodiment described above.

  For example, in the embodiment, the position of the center of gravity of the hammer body 22 is mainly adjusted by making the advance / retreat position of the second nest 60b constant and adjusting the advance / retreat positions of the first and third nests 60a, 60c in opposite directions. Is adjusted. Instead, the weight of the hammer body 22 is mainly adjusted by changing the advance / retreat positions of the first to third inserts 60a-60c uniformly and increasing / decreasing the thickness of all the recesses 43 uniformly. May be. Even when the weight of the hammer body 22 is adjusted in this way, the position of the center of gravity of the entire hammer 5 to which the weight plate 23 is attached changes. Therefore, the position of the center of gravity of the hammer 5 can be adjusted similarly.

  It is also possible to adjust the advance and retreat positions of the first to third inserts 60a to 60c with an adjustment pattern other than those described above, whereby the hammer body 22 having a different center of gravity position and / or weight according to the adjustment pattern. Thus, the hammer 5 having a desired center of gravity position can be realized.

  In addition, when the adjustment of the center of gravity of the hammer 5 is not performed so finely and the number of adjustment steps such as the center of gravity of the hammer body 22 may be small, a part of the first to third nestings 60a to 60c may be moved forward and backward. Or you may adjust the advance / retreat position of only the 1st-3rd nesting 60a-60c of one of the fixed side mold plate 52 and the movable side mold plate 56. Alternatively, the first to third inserts 60 a to 60 c may be provided only on one of the fixed side mold plate 52 and the movable side mold plate 56. Moreover, instead of the first to third inserts 60a to 60c that can be moved forward and backward, a plurality of fixed inserts having different lengths are adopted, and they are used while being exchanged according to the thickness of the recess 43 to be changed. Also good.

  Furthermore, contrary to the above, when adjusting the position of the center of gravity of the hammer 5 more finely, the types of the hammer body 22 may be increased than in the embodiment. For example, by increasing the number of types of hammer main bodies 22 to the same number as the number of keys 2 in a predetermined sound range, and arranging these hammer main bodies 22 and weight plates 23 in the same manner as in the embodiment, the bass side is spread over the entire sound range. It is possible to realize a distribution of the center of gravity of the hammer 5 that is very close to the grand piano so that the center of gravity gradually changes toward the tip side of the hammer 5 for each key 2 as it goes to. Thereby, a good touch feeling very close to a grand piano can be obtained. In addition, the detailed configuration can be appropriately changed within the scope of the gist of the present invention.

2 key 2a white key 2b black key 5 hammer 22 hammer body 23 weight plate (weight)
43 Hammer body recess 43a Front recess 43b Middle recess 43c Rear recess 52 Fixed mold plate 56 Movable mold plate 58a Cavity 58b Cavity 60a First insert (nesting)
60b Second nesting (nesting)
60c Third nesting (nesting)
62a Adjustment screw 62b Adjustment screw 62c Adjustment screw

Claims (5)

A key that is pressed by a key comprising a synthetic resin arm-shaped hammer body having a plurality of recesses arranged side by side along the length direction thereof, and a weight made of a material having a specific gravity greater than that of the synthetic resin. A method of manufacturing a hammer for an electronic keyboard instrument that rotates in conjunction with
Preparing a fixed mold plate and a movable mold plate each having a cavity having a shape complementary to the side shape of the hammer body;
A plurality of nestings each having a shape complementary to each of the plurality of recesses of the hammer body are attached to a predetermined position of at least one of the fixed side mold plate and the movable side mold plate so as to be movable forward and backward,
Adjusting the advancing and retreating positions of the plurality of nests with respect to the cavity independently of each other;
A method of manufacturing a hammer for an electronic keyboard instrument, wherein the hammer body is molded by injecting molten synthetic resin into the cavity in a state where the fixed side mold plate and the movable side mold plate are clamped. .   A plurality of types of hammer bodies having different weights and / or barycentric positions are formed by adjusting the advancing / retreating positions of the plurality of nestings by a plurality of combination patterns having different combinations of the advancing / retreating positions. A method of manufacturing a hammer for an electronic keyboard instrument according to claim 1. A plurality of types of weights having different weights are prepared as the weights,
3. The method of manufacturing a hammer for an electronic keyboard instrument according to claim 2, wherein a weight selected from the plurality of types of weights is attached to a hammer body selected from the plurality of types of hammer bodies.   The electronic keyboard instrument according to claim 3, wherein one kind of the weight is selected for each of a plurality of predetermined sound ranges, and a plurality of types of the hammer bodies are selected in each of the plurality of sound ranges. A method for manufacturing a hammer.   A hammer for an electronic keyboard instrument, comprising a hammer body manufactured by the method for manufacturing a hammer for an electronic keyboard instrument according to any one of claims 1 to 4.

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