JPS6336385Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an electromagnetic plunger for a player piano that has a simple structure and is capable of effectively absorbing shocks when keys are pressed.

[Conventional technology]

Generally, this type of electromagnetic plunger used in player pianos has a coil bobbin 2 fitted and fixed to the outer circumferential surface of a brass guide pipe 1, and a coil wound around the outer circumferential surface of the coil bobbin 2, as shown in FIG. The rotated solenoid coil 3 and the movable iron core 4 passed through the guide pipe 1 with a slight gap maintained.
The yoke 5 is made of a magnetic material such as soft iron and has a cylindrical shape, for example, and provides a magnetic path by housing the solenoid coil 3 therein. When the solenoid coil 3 is excited by an electric signal obtained by reproducing a pre-recorded electric signal,
The magnetic flux generated at this time attracts and raises the movable iron core 4. Therefore, the key 6 is pushed up by the movable iron core 4 and operates as if the key had been pressed. The movable core 4 is elastically supported by a spring 7 and is locked at the initial position.
This spring 7 automatically adjusts the position of the movable core 4 and always biases the movable core 4 upward, thereby improving the startup characteristics during driving, reducing power consumption, and reducing heat generation. There is.

[The problem that the idea aims to solve]

However, in such conventional electromagnetic plungers, although a buffer member 8 made of felt, rubber, etc. is attached to the top end surface of the movable iron core 4, it is not possible to perform a keystroke operation similar to keystroke operation using fingers with this alone. . In other words, when playing a piano, the suppleness and softness of the fingers allows for key operations unique to the piano, thereby enabling subtle performance expression. It was difficult to make them have characteristics similar to those of fingers, and as a result, it was not possible to faithfully reproduce the performer's performance.

Therefore, this invention solves the above-mentioned drawbacks, effectively absorbs the shock when keying is performed by providing an air damping chamber in the movable yoke, and enables keystrokes that are similar to keystrokes with fingers. An object of the present invention is to provide an electromagnetic plunger for a self-playing piano that can perform the following functions.

[Means to solve the problem]

In order to achieve the above object, this invention includes a solenoid coil, a fixed yoke and a movable yoke that are disposed axially opposite to each other in the center hole of the solenoid coil, and a fixed yoke and a movable yoke that are slidably inserted into both of these yokes. A movable core that moves toward the fixed yoke together with the movable yoke to operate the key when the solenoid coil is energized, and a spring that elastically supports the movable core and biases the movable core in the direction of the key. a hole into which one end of the movable iron core is slidably inserted, one end of which communicates with the inner end of the hole, one end of the movable iron core being slidably positioned therein while being prevented from coming off; An air damping chamber is provided which communicates with the outside through a small hole and through which internal air enters and exits as the movable core moves.In this air damping chamber, one end of the movable core is directed toward the key, and the movable yoke is located in the opposite direction from the key. A shock-absorbing spring that biases the body is housed.

[Effect]

When the movable yoke is absorbed during driving, the kinetic energy of the movable iron core is absorbed and consumed by the fluid viscosity of the air flow flowing out from the air damping chamber, thereby absorbing the impact when a key is pressed.

〔Example〕

This invention will be described in detail below based on embodiments shown in the drawings.

FIG. 2 is a longitudinal sectional view showing an embodiment of the electromagnetic plunger for a player piano according to this invention. Components in the figure that are the same as those in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted. Inside the coil bobbin 2, a fixed yoke 10, a movable iron core 4 and a movable yoke 11 constituting movable members are disposed.
are arranged facing each other in the axial direction. The upper end of the fixed yoke 10 is connected to the inner hole 1 of the coil bobbin 2.
2 and a hole 13 provided in the center of the upper surface of the yoke 5, and the lower end thereof forms a tapered portion 14 having an inverted truncated conical shape.

The movable iron core 4 is loosely inserted into the center hole 15 of the fixed yoke 10 with a slight gap, and its upper and lower ends protrude above and below the yoke 5. A push-up button 16 made of rubber or the like is integrally attached to the upper protruding end of the movable core 4.
Further, a buffer member 17 made of felt, rubber, etc. is provided at the center of the upper surface of the button 16. An annular groove 18 having a substantially U-shaped cross section is formed on the lower surface of the push-up button 16, and the upper end of the spring 7 is inserted and held in this groove 18. The lower end of the spring 7 abuts against the upper surface of the yoke 5, thereby constantly urging the movable core 4 upward and causing the buffer member 17 to abut against the lower surface of the rear end of the key 6. In this case, the force of the spring 7 is set to an appropriate value within a range in which the key 6 is not pushed up by the movable iron core 4.

On the other hand, the movable yoke 11 is slidably fitted to the outer peripheral surface of the lower end of the movable core 4, and is prevented from coming off downward by a collar 20 integrally provided at the lower end of the movable core 4. has been done. A tapered hole 21 is formed in the upper end surface of the movable yoke 11 in correspondence with the tapered portion 14 of the fixed yoke 10, and a magnetic gap 22 is formed between the tapered hole 21 and the tapered portion 14. There is. A hole 26 is formed in the center of the interior of the movable yoke 11, the upper end of which opens at the bottom of the tapered hole 21, and into which the lower end of the movable iron core 4 is inserted. An air damping chamber 27 is formed in which a collar 20 provided at the lower end of the movable iron core 4 is slidably inserted.
A spring pressure adjustment screw 3 is provided at the lower end opening of this chamber 27.
0 is screwed in.

The air damping chamber 27 is for absorbing the shock caused by the movable iron core 4 when the key is pressed, and has a hole diameter larger than the hole 26, and the lower end thereof is a small hole formed through the spring pressure adjustment screw 30. It communicates with the outside via 32, and inside there is a movable iron core 4 upwardly.
Shock absorbing springs 28 are housed to urge the movable yoke 11 downward in opposite directions.

By rotating and adjusting the spring pressure adjusting screw 30, the spring force of the spring 28 can be variably set.

Note that 33 is a stopper fixed to the lower surface of the yoke 5, 34 is an O-ring, and 35 is a felt ring.

In the electromagnetic plunger having such a configuration, when a signal current is supplied to the solenoid coil 3 to excite the coil 3, the movable yoke 11 is attracted and raised by the action of the magnetic flux generated in the magnetic gap 22. The movable iron core 4 also rises, and the buffer member 17 of the push-up button 16 pushes up the lower surface of the key 6. At this time, the air damping chamber 27 is configured such that the movable iron core 4, which constitutes a part of the movable member, and the movable yoke 11, which also constitutes a part of the movable member, are movable relative to each other, and these two members brake each other. Since the force acting as shown in FIG. As a result, key 6
is activated as if a key had been pressed by hand.

That is, when the movable yoke 11 begins to absorb and rise, the movable iron core 4 also tries to rise together with it, but the movable iron core 4 receives a reaction force from the key 6 caused by the key 6 and the action mechanism (not shown). Therefore, when a strong force of a predetermined value or more is applied between the movable core 4 and the movable yoke 11, the movable core 4 and the movable yoke 11 can move relative to each other.
The movable iron core 4 does not move integrally with the movable yoke 11, so only the movable yoke 11 begins to rise, and the spring pressure adjustment screw 30 and the collar 20 of the movable iron core 4
As a result, the shock absorbing spring 28 begins to be compressed.
Therefore, in this state, the movable yoke 11 is
It moves while receiving part of the reaction force from the air via the spring 28, and as a result of the relative movement between the movable iron core 4 and the movable yoke 11, it is confined within the air damping chamber 27. Air is small hole 32
At this time, the key 6 escapes more and creates flow resistance, but the remainder of the reaction force from the key 6 is mostly balanced with this flow resistance, and is thus braked. When the force of the spring 28 in the compressed state and the reaction force from the key 6 maintain their engagement, this is also the time when the air flow in the small hole 32 has stopped and flow resistance no longer occurs. For the first time, the movable iron core 4 rises integrally with the movable yoke 11. The amount of compression of this spring 28 increases compared to the rising speed of the movable yoke 11, and after the movable iron core 4 begins to move integrally with the movable yoke 11, it decreases due to a decrease in the reaction force due to the inertia of the key 6. . When the key 6 rises a certain distance, the mounting structure prevents the key 6 from rising any further, so the movement speed becomes zero and the reaction force against the movable member becomes maximum. At this time, the movable member receives a large impact, but part of this force is absorbed by the impact absorbing spring 28.
is absorbed by being compressed by the movable iron core 4. Moreover, the relative movement of the movable iron core 4 and the movable yoke 11 during driving is damped by the action of the air damping chamber 27 as described above, and the kinetic energy is absorbed and consumed by the fluid viscosity of the air flow, so that the buffer member 17 is soft. Press key 6 with the same operating force change pattern as when pressing a key with a finger.
Push up. Therefore, it is possible to perform a keystroke operation that approximates the keystroke force exerted by fingers, and it is possible to more faithfully reproduce the subtle performance expressions of the performer.

When the solenoid coil 3 is de-energized, the movable member returns to its initial position by its own weight. Even at this time, however, the air damping chamber 27 functions to absorb the impact generated when the returning operation is completed.

[Effect of idea]

As described above, the electromagnetic plunger for a player piano according to this invention has a movable yoke movably fitted to a movable iron core, an air damping chamber that communicates with the outside is provided inside the movable yoke, and an air damping chamber that communicates with the outside is provided inside the movable yoke. The structure incorporates a shock-absorbing spring that biases the iron core and movable yoke in opposite directions, so it can effectively absorb the shock when keys are pressed, and the key-pressing operation is similar to that of finger-based keystrokes. As a result, subtle performance expressions can be reproduced more faithfully. In addition, it is possible to prevent vibration due to the recoil of the key when the key is returned, and furthermore, the structure is simple, and its practical effects are very great.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a conventional electromagnetic plunger, and FIG. 2 is a longitudinal sectional view showing an embodiment of the electromagnetic plunger for a self-playing piano according to the invention. 2...Coil bobbin, 3...Solenoid coil, 4...Movable iron core, 6...Key, 7...Spring, 1
0... Fixed yoke, 11... Movable yoke, 26...
... hole, 27 ... air damping chamber, 28 ... shock absorption spring, 32 ... small hole.

Claims (1)

[Scope of utility model registration request] a solenoid coil; a fixed yoke and a movable yoke disposed axially opposite to each other in a center hole of the solenoid coil; and a fixed yoke and a movable yoke that are slidably inserted into both the yokes and are inserted together with the movable yoke when the solenoid coil is energized. A movable iron core that moves in the direction of the fixed yoke to operate the key, and a spring that elastically supports the movable iron core and biases it in the direction of the key, one end of the movable iron core being able to freely slide inside the movable yoke. One end of the movable iron core is inserted into the hole and one end communicates with the inner end of the hole so that one end of the movable iron core is slidably positioned inside to be prevented from coming off, and the other end communicates with the outside through a small hole and the movable core An air damping chamber is provided in which internal air enters and exits as the core moves, and a shock absorbing spring that biases one end of the movable core toward the key and the movable yoke in the opposite direction to the key is housed in the air damping chamber. An electromagnetic plunger for a self-playing piano, which is characterized by: