JPH0535435Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention relates to a player piano, which provides uniform noise prevention characteristics and facilitates assembly work.

[Prior Art] Conventionally, an actuator shown in FIG. 2 is known as a key drive actuator used in this type of automatic piano. That is, the actuator 10
A coil bobbin 2 is fitted and fixed to the outer circumference of a brass guide pipe 1, a solenoid coil 3 is wound around the outer circumference of the coil bobbin 2, and a small gap is maintained between the coil bobbin 2 and the solenoid coil 3 wound on the outer circumference of the coil bobbin 2. a plunger 4 that is slidably inserted in the axial direction; and a yoke that is formed of a magnetic material such as soft iron and that provides a magnetic path by housing the solenoid coil 3 therein together with the guide pipe 1 and the coil bobbin 2. 5, etc., and is arranged below the rear end of the key 6. Then, the solenoid coil 3 is excited by the application of the voltage pulse, and the plunger 4 is attracted and raised, so that the key 6 operates as if it were pressed by hand. Note that 7 is a spring that elastically supports the plunger 4 and locks it at the initial position.

[Problem that the invention attempts to solve]

By the way, plunger 4 when pushing up key 6
The acceleration of the keys is quite large, which causes a large impact noise when the keys are pressed. Therefore, in the conventional actuator of this kind, a push-up button 8 made of plastic or the like is provided at the tip of the plunger 4, and a buffer member 9 made of felt or the like is provided on the top surface of this button 8, or a third As shown in the figure, a push-up button 11 made of an elastic material such as rubber is fitted, and a buffer member 9 is provided at the center of the surface of the push-up button 11 to prevent impact noise from occurring.

However, in such a structure, it is not possible to uniformly prevent impact noise from occurring due to variations in the dimensions of the buffer member 9 and the buffer characteristics of the material.
Moreover, the rise characteristics of the keys 6 varied, making it difficult to reproduce the performance faithfully.

[Means for solving problems]

The self-playing piano according to this invention was made to solve the above-mentioned problems, and includes a key, an actuator, a key drive section, and a raised button, and the actuator has a solenoid coil on its outer circumferential surface. A wound bobbin is disposed between an upper yoke and a lower yoke, a plunger is disposed inside the bobbin so as to be movable in the axial direction thereof, and the key drive section is arranged so that the plunger is movable in the axial direction of the bobbin. A button locking portion that penetrates the insertion hole of the yoke and has a head and a neck portion and has a generally T-shaped cross section is formed on the upper end surface of the button locking portion, and the protruding button is made of an elastic body,
The button locking part is removably fitted in the center of the upper surface, forming a substantially T-shaped recess larger than the thickness of the head, and having an outer diameter smaller than the hole diameter of the insertion hole, and the solenoid coil. The key driving section pushes up the lower surface of the rear end of the key by upward movement of the plunger due to excitation.

[Effect]

The raised button has a recess larger than the button locking portion, and the button locking portion is removably fitted into the recess to form an air gap inside. This air gap uniformly absorbs impact energy when keys are pressed, stably preventing impact noise from occurring, and achieving quiet and uniform start-up characteristics. By making it smaller, the push-up button can be attached to the plunger even after the upper yoke is assembled, and the upper yoke can be removed without removing the push-up button from the plunger, improving assembly work efficiency.

〔Example〕

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

FIG. 1 is a cross-sectional view showing an embodiment of a self-playing piano according to this invention. In the figure, the same components as in FIGS. 2 and 3 are indicated by the same reference numerals. In the figure, an actuator 21 is disposed on the upper surface of the rear end of the shelf board 20 in correspondence with the lower surface of the rear end of the key 6.

The actuator 21 includes an upper yoke 22 and a lower yoke 23 that face each other vertically, and a bobbin 2 having a solenoid coil 3 wound around the outer circumferential surface is disposed between the yokes 22 and 23.
The upper yoke 22 and the lower yoke 23 extend long in a direction perpendicular to the longitudinal direction of the keys 6, thereby providing a common magnetic path for the plurality of keys 6. The lower end of the bobbin 2 passes through a through hole 25 provided in the lower yoke 23, and a recess 2 formed on the shelf board 20
6 is fitted. A plunger 4 is fitted into the bobbin 2 so as to be slidable in the axial direction, that is, in the vertical direction, and is elastically supported by a spring 27. A buffer member 28 such as felt is adhesively fixed to the upper surface of the bobbin 2, and a key drive section 30 is integrally provided in the center of the upper surface. A button locking portion 32 is integrally provided at the center of the upper end surface of the key drive portion 30 to protrude through an insertion hole 31 provided in the upper yoke 22 and closely oppose the lower surface of the rear end of the key 6. In part 32, there is a push-up button 3 that characterizes this invention.
3 is removably fitted from above. The button locking portion 32 integrally includes a head portion 32A and a neck portion 32B, and has a substantially T-shaped cross section. The push-up button 33 is formed of an elastic material such as rubber into a cylindrical shape having approximately the same outer diameter as the key drive section 30, and the button locking section 32 is formed at the center of the lower surface of the button 33.
A substantially T-shaped recess 35 into which the holder is fitted is formed. The inside of the recess 35 is formed to be thicker than the head 32A, thereby forming a hollow air gap 37. And push up button 3
The upper end surface of the key 3 lightly contacts the lower surface of the rear end of the key 6.

Note that 39 is a buffer member disposed on the inner bottom surface of the bobbin 2.

In the actuator 21 having such a configuration, when a signal current is supplied to the solenoid coil 3 to excite the coil 3, the plunger 4 moves upward due to the action of magnetic flux generated in the magnetic gap G between the upper yoke 22 and the plunger 4. , the kinetic energy is transmitted to the key 6 via the push-up button 33. As a result, the key 6 is pushed up and operates as if it were pressed by hand.

Here, the push-up button 33 has a hollow air gap 37, which is easily deformed and absorbs impact force as elastic strain energy and also as compression energy of the air within the air gap 37.
In this case, the impact characteristics are very stable because the push-up button can be manufactured by molding, etc., and the dimensions, shape, and elasticity can be made uniform, without causing variations unlike the conventional impact member 9. , also contributes to stabilizing the rise characteristics of the key 6.

Furthermore, the push-up button 33 has an outer diameter that is equal to the insertion hole 31.
Since the diameter of the hole is smaller than that of the hole, it can be attached to the plunger 4 from above the upper yoke 22, and when the upper yoke 22 is removed, the push-up button 33 does not get in the way and can be easily removed. In other words, the installation procedure of the upper yoke 22 and the push-up button 33 is not mutually restricted by these two members.
Excellent assembly workability. Further, since the upper and lower yokes 22 and 23 extend in common to the plurality of keys 6, the number of parts is reduced.

[Effect of idea]

As described above, the automatic performance piano according to the present invention has a simple structure, stably prevents impact noise during keystrokes, and is effective in making the key rise characteristics uniform. Therefore, it is possible to improve the rising characteristics of the keys as they become quieter, and to faithfully reproduce the performance. Additionally, the push-up button and upper yoke can be easily attached and removed, improving assembly workability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of this invention, FIG. 2 is a sectional view showing an example of a conventional actuator, and FIG. 3 is a sectional view showing a conventional example of a push-up button. 2...Bobbin, 3...Solenoid coil, 4...
...Plunger, 6...Key, 22...Upper yoke,
23...Lower yoke, 30...Key drive unit, 31...
...Insertion hole, 33...Push-up button, 37...Air gap.

Claims (1)

[Claims for Utility Model Registration] Key 6, actuator 21, and key drive unit 30
and an uplift button 33, the actuator 21 moves the bobbin 2, around which the solenoid coil 3 is wound, onto the upper yoke 2.
2 and the lower yoke 23, and a plunger 4 is disposed inside the bobbin 2 so as to be movable in the axial direction thereof, and the key driving section 30 is connected to the upper yoke 22 on the upper surface of the plunger 4. passes through the insertion hole 31 of the head 32A and the neck 32B on its upper end surface.
The projecting button 33 is made of an elastic body, and the button locking part 32 is removably fitted in the center of the upper surface of the button locking part 32, and the button locking part 32 is detachably fitted in the center of the upper surface of the button 33. A substantially T-shaped recess 35 having a thickness greater than that of the insertion hole 31 is formed, and the outer diameter is greater than the thickness of the insertion hole 31.
The automatic performance piano is characterized in that the key drive unit 30 pushes up the lower surface of the rear end of the key 6 by upward movement of the plunger 4 by excitation of the solenoid coil 3.