JP5791447B2 - Electronic piano key switch - Google Patents

Description

  The present invention relates to a key switch of an electronic piano that detects movement of a key or a hammer that rotates as the key is depressed as key depression information.

  As a conventional key switch of this type of electronic piano, for example, one disclosed in Patent Document 1 is known. The key switch is of a three-contact type that detects the movement of the key in three stages, and includes a dome-shaped rubber switch fixed to the lower surface of the key and a switch board disposed below the dome-shaped rubber switch. The rubber switch is provided with columnar first to third switch elements that hang from the top wall in a state of being arranged in the front-rear direction (the length direction of the key). Among these first to third switch elements, the first switch element is the longest and the third switch element is the shortest, and the first to third movable contacts are formed at the lower ends thereof. On the other hand, first to third fixed contacts are arranged in parallel on the switch board so as to face the first to third movable contacts, respectively.

  In this key switch, when the key rotates when the key is pressed, the rubber switch is pressed by the key, and the first to third movable contacts sequentially come into contact with the first to third fixed contacts as they are compressed and deformed. Thus, each ON signal is output.

  FIG. 10 shows an arrangement of a conventional general three-contact type fixed contact. As shown in the figure, each of the first to third fixed contacts cs1 to cs3 is different from a common contact (hatched contact) having the same reference potential by grounding to the ground or the like, and a potential different from the reference potential. It is comprised by the non-common contact (white contact) which has. These common contacts and non-common contacts are made of carbon or the like printed on the switch board, and are formed in a rectangular shape extending linearly in the front-rear direction (left-right direction in the figure), and in the left-right direction (up-down direction in the figure). Direction) in close proximity to each other. Further, the three common contacts and the three non-common contacts are juxtaposed in a state of being close to each other in the front-rear direction.

  When the key is depressed, the first to third movable contacts cm1 to cm3 made of carbon or the like come into contact with the common contact and the non-common contact of the first to third fixed contacts cs1 to cs3, and common / non-common. When the contact is conducted, an ON signal is output.

JP 2007-52357 A

  In the conventional key switch having the above-described configuration, the fixed contact when contacting the fixed contact due to variations in the operation (deformation) of the pressed rubber switch or the positional deviation when printing the fixed contact on the switch board. The relative position of the movable contact (hereinafter referred to as “contact position of the movable contact”) tends to shift in the front-rear direction (key length direction). On the other hand, in the conventional key switch, the three rectangular common contacts and non-common contacts of the first to third fixed contacts cs1 to cs3 are arranged in a state of being close to each other in the front-rear direction.

  For this reason, if the contact position of the movable contact is shifted in the front-rear direction, and the movable contact protrudes even slightly from the original fixed contact, the movable contact tends to mistakenly contact the adjacent fixed contact, which may cause erroneous detection. For example, as shown in FIG. 10, when the first movable contact cm1 protrudes from the position corresponding to the original first fixed contact cs1 (solid line position) to the second fixed contact cs2 side (broken line position), By contacting the non-common contact of the two fixed contacts cs2, an ON signal indicating that the second fixed contact cs2 is in an ON state is erroneously output.

  In addition, in order to stabilize the ON signal of the key switch and suppress the amount of heat generation, it is preferable that the electric resistance of the movable contact made of carbon or the like is lower. For that purpose, for example, the diameter of the movable contact is increased. It is effective to do. However, in the conventional key switch, if the diameter of the movable contact increases, the possibility of contacting the adjacent fixed contact increases with the displacement of the contact position, so the diameter of the movable contact must be limited.

  Furthermore, in order to eliminate the above-described problems, for example, it is conceivable to increase the length of the common contact and the non-common contact of each fixed contact, or increase the interval between the fixed contacts. However, since the total length of the three-contact type key switch is originally larger than that of the two-contact type, the above configuration further increases the overall length of the key switch and increases the size.

  The present invention has been made to solve such a problem. When the key switch is a three-contact type, the allowable range of displacement of the movable contact can be expanded without increasing the size of the key switch. Accordingly, it is an object of the present invention to provide a key switch for an electronic piano that can suppress malfunction and detect key press information with higher accuracy.

To this end, the invention is an electronic piano detects the movement of the one in which the rotating body of the hammer which rotates with the key depression and key, as the key depression information according to claim 1 of the present application And a substrate on which first, second, and third fixed contacts are arranged in parallel along the length of the rotating body, and each of the first to third fixed contacts is a rotating body. Consists of a common contact having a predetermined reference potential and a non-common contact having a potential different from the reference potential, which are arranged to face each other at a predetermined interval in an orthogonal direction orthogonal to the length direction of In each of the two fixed contacts, at least one common contact has an extending portion extending in an orthogonal direction so as to enter between the two non-common contacts, and is attached to the substrate. Elastic switch The main body and the switch body are arranged in parallel so as to face the first to third fixed contacts, respectively. It further comprises first, second and third movable contacts for outputting a signal representing key pressing information by sequentially contacting the common contact and the non-common contact of the fixed contact.

  According to the key switch of the electronic piano, the first to third fixed contacts are arranged side by side along the length direction of the rotating body that is one of the key and the hammer. Each of the first to third fixed contacts is constituted by a common contact having a predetermined reference potential and a non-common contact having a potential different from the reference potential, and each common contact and non-common contact has a length of the rotating body. They are opposed to each other at a predetermined interval in an orthogonal direction orthogonal to the direction.

  When the rotary body rotates as the key is pressed, the elastic switch body is pressed by the rotary body and is compressed and deformed. Due to the compression deformation of the switch body, the first to third movable contacts arranged in parallel with the switch body sequentially contact the common contact and the non-common contact of the first to third fixed contacts so as to straddle both. As a result, signals representing key pressing information are output.

  According to the present invention, in each of two adjacent fixed contacts, at least one common contact has an extending portion extending in an orthogonal direction so as to enter between two non-common contacts. Therefore, even if the contact position of the movable contact corresponding to these two fixed contacts is shifted in the length direction of the rotating body, and the movable contact slightly protrudes from the original fixed contact to the other fixed contact side, it is common at that position. The presence of the contact extension part keeps the contact state with the common contact point and prevents the contact with other non-common contact points of the other fixed contact points. To do. In this way, the allowable range of displacement of the movable contact can be expanded without increasing the size of the key switch, so that malfunction can be suppressed and key press information can be detected with higher accuracy.

It is a side view which shows the keyboard apparatus of the electronic piano to which this invention is applied in the state where a part was notched. It is a side view which shows the switch main body of a key switch. It is a perspective view which shows the switch main body unit which integrally molded the several switch main body from diagonally upward. It is a perspective view which shows the switch main body unit of FIG. 3 from diagonally downward. It is a side view which shows the state which attached the switch main body to the switch board | substrate. It is a top view which shows arrangement | positioning of the fixed contact in a switch board. It is a top view for demonstrating the positional relationship of the movable contact and fixed contact at the time of the action | operation of a key switch. It is a top view for demonstrating the positional relationship of a movable contact and a fixed contact at the time of the action | operation of the conventional key switch. It is a top view which shows arrangement | positioning of the fixed contact by a modification. It is a top view which shows arrangement | positioning of the fixed contact in the switch board of the conventional key switch.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an electronic piano keyboard apparatus according to an embodiment of 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 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 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, 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 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 inserted into the switch mounting portion 20 and is screwed to the switch mounting portion 20 at a central portion. 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 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 key switch 7 according to the present invention will be described in detail with reference to FIGS. The switch body 30 of the key switch 7 is made of a very soft rubber such as silicon rubber. As shown in FIGS. 3 and 4, the switch body 30 includes four switch bodies 30 arranged side by side, a base 41 that connects these switch bodies 30, and a plurality of mounting legs that protrude downward from the base 41. It is formed as a switch body unit 43 formed integrally with the portion 42.

  Each switch body 30 has an oval planar shape that is long in the front-rear direction, and is formed in a dome shape as a whole from a thin peripheral wall portion 44 that rises from the base 41 and a movable portion 45 that is connected to the thin peripheral wall portion 44. As shown in FIG. 2, the surface of the movable part 45 is inclined so as to approach the base 41 toward the front side (right side in FIG. 2).

  Three cylindrical concave portions 46 to 48 are formed in the front-rear direction on the surface of the movable portion 45, and the first to third switches are formed from the lower edges of the concave portions 46 to 48 through the thin portion 49. The elements S1 to S3 are suspended. First to third movable contacts CM1 to CM3 made of carbon are provided at lower ends of the first to third switch elements S1 to S3, respectively. The movable portion 45 is provided with a support protrusion 50 on the front side of the first switch element S1. The support protrusion 50 has a block shape and extends to the vicinity of the base 41.

  Further, on the surface of the movable portion 45, two front and rear pressed projections (hereinafter simply referred to as “projections”) 51A and 51B are provided adjacent to each other on the left and right sides of the central recess 47, respectively. . These protrusions 51A and 51B have a substantially semicircular side shape, and their sizes are the same.

  As shown in FIG. 5, the switch body 30 configured as described above has a plurality of leg portions 42 inserted into the corresponding holes 52 of the switch substrate 29 by using its elasticity, so that It is attached to the bottom surface. When the key 2 is released, the actuator portion 26 of the hammer 5 faces the protrusion 51B on the rear side of the switch body 30 in a close state. FIG. 5 shows a state immediately after the actuator portion 26 comes into contact with the protrusion 51B as the key is depressed.

  Further, in the key release state, the support protrusion 50 of the movable portion 45 is opposed to the switch substrate 29 in a close state, and the first to third movable contacts CM1 to CM3 are first to first formed on the switch substrate 29. The three fixed contacts CS1 to CS3 are opposed to each other. The distance between the movable / fixed contacts is shorter in the order of the first movable / fixed contact CM1, CS1, the second movable / fixed contact CM2, CS2, and the third movable / fixed contact CM3, CS3, that is, the shorter the front one. It has become.

  As shown in FIG. 6, the first to third fixed contacts CS1 to CS3 are juxtaposed in the front-rear direction (the left-right direction in the figure), and the first common contact CC1 and the first non-common contact CN1, respectively. The contact pair includes a second common contact CC2 and a second non-common contact CN2, and a third common contact CC3 and a third non-common contact CN3. The first to third common contacts CC1 to CC3 shown with hatching in the figure are grounded and have the same reference potential. On the other hand, the first to third non-common contacts CN1 to CN3 have a predetermined potential different from the reference potential.

  As shown in the figure, the first common contact CC1 and the first non-common contact CN1 are formed in a rectangular shape that is long in the front-rear direction, have the same length and width, and are larger than the diameter of the first movable contact CM1. They are opposed to each other in the left-right direction (vertical direction in the figure) with a small predetermined interval.

  On the other hand, the second and third common contacts CC2 and CC3 and the second and third non-common contacts CN2 and CN3 are both composed of a main body portion and an extending portion extending from one end thereof, and are formed in an L shape. Is formed. The main body parts BC2 and BN2 of the second common contact CC2 and the second non-common contact CN2 are formed in a rectangular shape having the same length and width as the first common contact CC1 and the first non-common contact CN1, respectively. It extends in the front-rear direction on the extension line, and is opposed to each other with a predetermined interval. On the other hand, the extending portion EC2 of the second common contact CC2 extends in the left-right direction so as to enter between the first non-common contact CN1 and the main body BN2 of the second non-common contact CN2 from the front end of the main body BC2. It extends to. Further, the extending portion EN2 of the second non-common contact CN2 enters between the main body portion BC2 of the second common contact C2 and the main body portion BC3 of the third common contact CC3 from the rear end portion of the main body portion BN2. In addition, it extends in the left-right direction.

  Similarly, the body portions BC3 and BN3 of the third common contact CC3 and the third non-common contact CN3 have the same length and width as the body portions BC2 and BN2 of the second common contact CC2 and the second non-common contact CN2, respectively. It has a rectangular shape, and extends in the front-rear direction on these extension lines, and is opposed to each other with a predetermined interval. On the other hand, the extending portion EC3 of the third common contact CC3 enters between the main body portion BN2 of the second non-common contact CN2 and the main body portion BN3 of the third non-common contact CN3 from the front end portion of the main body portion BC3. The extension portion EN3 of the third non-common contact CN3 extends in the left-right direction from the rear end portion of the main body portion BN3 to the rear side of the main body portion BC3 of the third common contact CC3. It extends.

  Next, the operation of the key switch 7 configured as described above will be described in detail with reference to FIGS. When the key 2 is depressed, the hammer 5 rotates in the clockwise direction in FIG. 5, and the actuator portion 26 presses the switch body 30, whereby the switch body 30 is compressed and deformed. As a result of this compression deformation, the first movable contact CM1 first contacts the first common contact CC1 and the first non-common contact CN1 of the first fixed contact CS1 at the same time, so that both the contacts CC1, CN1 The first switch element S1 is turned ON.

  When the rotation of the hammer 5 advances, the second movable contact CM2 contacts the second common contact CC2 and the second non-common contact CN2 of the second fixed contact CS2 at the same time so as to straddle the two contacts CC2. , CN2 are conducted, and the second switch element S2 is turned on. When the hammer 5 further rotates, the third movable contact CM3 contacts the third common contact CC3 and the third non-common contact CN3 of the third fixed contact CS3 at the same time so as to straddle both, so that both the contacts CC3, CN3 Is conducted, and the third switch element S3 is turned ON.

  The ON signals from the first to third switch elements S1 to S3 are sequentially input to the sound generation control device. For example, the sound generation control device determines that the key 2 has been pressed and the key number by the ON operation of the key switch 7, and determines the hammer 5 from the ON time difference between the first to third switch elements S1 to S3. The rotation speed is calculated, and the pronunciation of the electronic piano is controlled based on the result.

  Further, for example, as shown by a broken line in FIG. 7, when the contact position of the first movable contact CM1 is shifted rearward and the first movable contact CM1 protrudes from the first fixed contact CS1, the first movable contact CM1. Is in contact with the first non-common contact CN1 and the extended part EC2 of the second common contact CC2 existing behind the first non-common contact CN1, so that the contact state with the common contact is maintained and the second fixed contact CS1. Contact with the non-common contact CN2. Thereby, the ON state of the first switch element S1 is maintained.

  Although not shown, when the second movable contact CM2 protrudes from the second fixed contact CS2 to the front side, the second non-common contact CN2 and the extending portion EC2 of the second common contact CC2 existing on the front side thereof If the second fixed contact CS2 protrudes rearward from the second fixed contact CS2, the second non-contact contact CN2 and the extended portion EC3 of the third common contact CC3 existing behind the second noncontact contact CN2 come into contact with each other. The ON state of the second switch element S2 is maintained. Similarly, when the third movable contact CM3 protrudes to the front side from the third fixed contact CS3, it contacts the third non-common contact CN3 and the extension EC3 of the third common contact CC3 existing on the front side. As a result, the ON state of the third switch element S3 is maintained.

  Further, as shown in FIG. 7, the limit allowed when the contact position of the first movable contact CM1 is shifted to the rear side is determined by the rear edge of the extending part EC2. Therefore, if the distance between the limit position and the center position of the first fixed contact CS1 is defined as an allowable range of deviation of the first movable contact CM1, the allowable range in this case is L1.

  On the other hand, as shown by a broken line in FIG. 8, in the conventional key switch, when the contact position of the first movable contact cm1 is shifted to the rear side, the limit position is close to the first fixed contact cs1. Since it is determined by the leading edge of the second fixed contact cs2, the allowable range is L1 ′ smaller than L1 according to the present embodiment. That is, according to the present embodiment, it is understood that the allowable range of deviation of the first movable contact CM1 is expanded.

  As described above, according to the present embodiment, the contact positions of the first to third movable contacts CM1 to CM3 are shifted in the length direction of the hammer 5, and the first to third movable contacts CM1 to CM3 are the original fixed contacts. Even when it protrudes, the contact portions with the common contacts of the first to third movable contacts CM1 to CM3 are maintained by the extended portions EC2 and EC3 of the second and third common contacts CC2 and CC3 existing at that position. In addition, contact with the non-common contact of other fixed contacts is prevented. As a result, the allowable range of deviation of the first to third movable contacts CM1 to CM3 can be expanded without increasing the size of the key switch 7, and thus malfunction can be suppressed and key press information can be detected more accurately. it can.

  FIG. 9 shows a modification of the above-described embodiment. This modification differs from the above-described embodiment only in the arrangement pattern of the first to third fixed contacts CS1 to CS3. As shown in the figure, in this modification, the three common contacts CC1 to CC3 and the non-common contacts CN1 to CN3 of the first to third fixed contacts CS1 to CS3 are alternately arranged in the left-right direction.

  The first and second common contacts CC1 and CC2 are provided with an extending part EC12 so as to connect the end parts close to each other, and the extending part EC12 is provided with the first and second non-commons. The contact points CN1 and CN2 extend in the left-right direction. Similarly, the second and third common contacts CC2 and CC3 are provided with an extending portion EC23 so as to connect the end portions close to each other, and the extending portion EC23 is connected to the second and third common contacts CC2 and CC3. 3 It extends in the left-right direction between the non-common contacts CN2 and CN3. Other configurations are the same as those of the embodiment.

  According to this configuration, as indicated by broken lines in FIG. 9, the contact positions of the first to third movable contacts CM1 to CM3 are shifted in the length direction of the hammer 5, and the first to third movable contacts CM1 to CM3 are inherently located. Even when the fixed contact protrudes from the fixed contact, the contact portion with the common contact of the first to third movable contacts CM1 to CM3 is maintained by the extended portion EC12 or the extended portion EC23 of the common contact existing at that position. The contact of the other fixed contact with the non-common contact is prevented. Therefore, the above-described effects according to the embodiment can be obtained similarly.

  In addition, this invention can be implemented in various aspects, without being limited to the embodiment described above. For example, the arrangement pattern of the common contact, the non-common contact, and the extension portion of the fixed contact shown in the embodiment and the modification is merely an example, and the extension portion of the common contact is between two adjacent non-contacts. Any arrangement pattern can be adopted as long as it is arranged to extend.

  In the embodiment, the key switch is configured to be pressed with a hammer. However, the present invention is not limited thereto, and may be applied to a key switch pressed with a key. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

2 key 2a white key 2b black key 5 hammer (rotating body)
7 Key switch 29 Switch board (board)
30 Switch body CM1 First movable contact CM2 Second movable contact CM3 Third movable contact CS1 First fixed contact CS2 Second fixed contact CS3 Third fixed contact CC1 First common contact CC2 Second common contact CC3 Third common contact CN1 First 1 non-common contact CN2 second non-common contact CN3 third non-common contact NC2 second common contact extension NC3 third common contact extension NC12 first and second common contact extension NC23 second and second Extension part of third common contact

Claims (1)

One in which the rotary body movement of the hammer which rotates with the key and the key depression of the key, a key switch of the electronic piano detects the key depression information,
Comprising a substrate on which first, second and third fixed contacts are arranged in parallel along the length direction of the rotating body;
Each of the first to third fixed contacts includes a common contact having a predetermined reference potential and arranged to face each other at a predetermined interval in an orthogonal direction orthogonal to the length direction of the rotating body. Consists of non-common contacts having a potential different from the reference potential,
In each of the two adjacent fixed contacts, at least one of the common contacts has an extending portion extending in the orthogonal direction so as to enter between the two non-common contacts,
An elastic switch body attached to the substrate and facing the rotating body in the key release state;
As the switch body is pressed by the rotating body that is arranged in parallel to the switch body so as to face the first to third fixed contacts and rotates when the key is pressed, the first to first First, second and third movable contacts for outputting a signal representing the key pressing information by sequentially contacting the common contact and the non-common contact of the three fixed contacts;
An electronic piano key switch, further comprising:

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