JPH0631940B2 - Keyboard lid open / close device for keyboard instruments - Google Patents

Description

The present invention relates to a rotary damper for opening and closing a keyboard lid of a keyboard instrument, and in particular, a viscous fluid and a spring are provided in the rotary damper,
The restoring force by the spring in the initial stage and the braking force by the viscous resistance in the final stage are generated.

<Prior Art> A conventional keyboard lid opening / closing device of this type is, for example, 1987
As proposed in Japanese Utility Model Registration Application No. 67993, the keyboard lid opening / closing device according to this prior application has a case 1 and a uniform diameter rotatably supported by the case 1, as shown in FIG. 2 and a coil spring 3 which is wound in close contact with the shaft 2. One end of this coil spring 3 is movably inserted in a groove 4 formed in the case 1, and the other end of the coil spring 3 is not fixed to the shaft 2 but simply the shaft 2
It is free just to be supported by winding.

When installing the keyboard lid, between the two sides of the keyboard lid and the two arms of the keyboard instrument body, the rotary damper shown in FIG. 2 (the winding direction of the coil spring 3 is different between the left and the right dampers). , Respectively, and the case 1 and the engaging end 5 of the shaft 2 are fixed to the keyboard lid and the arm member, respectively. The winding direction of the coil spring 3 is a direction in which the shaft 2 is tightened when the free end of the coil spring 3 is dragged in the rotating direction of the shaft 2 when the keyboard lid is changed from the open state to the closed state. Therefore, when the keyboard lid is rotated so as to be in the closed state, one end of the coil spring 3 moves in the winding direction as the case 1 rotates, and the coil spring 3 is initially slid on the outer surface of the shaft 2 while the coil spring 3 is being rotated. The diameter of each of the constituent coil elements is reduced. As a result, eventually the coil spring 3 tightens the shaft 2,
The frictional resistance imparts strong braking to the case 1.

<Problems to be Solved by the Invention> However, in the rotary damper according to the above configuration, since the coil spring 3 slides on the outer surface of the shaft 2, noise due to friction is generated, and the performer or the owner of the keyboard device is caused. There was a problem of giving an unpleasant feeling.

Further, there is a problem that the braking force becomes unstable because the value of the generated frictional resistance is unstable.

Therefore, an object of the present invention is to provide a keyboard lid opening / closing device that is quiet and has stable braking force.

<Means for Solving the Problems> According to the present invention, a braking force is generated by viscous resistance between a case and a shaft, and if a restoring force is generated by springs having both ends fixed, noise caused by the generation of the braking force is prevented. The present invention has been made in view of the fact that it is possible, and its gist is a keyboard lid opening / closing device for a keyboard instrument, and this keyboard lid opening / closing device has a rotary damper (15), and the rotary damper (15) is a keyboard lid. A resistance force is generated against the rotation of (13) in the closing direction, and the case (21) and the shaft (25).
And a viscous body (29) and a coil spring (33), and the case (21) is fixedly attached to either the keyboard lid (13) or the keyboard instrument body (12). , Having an internal space (24) and an axis (25)
Is rotatably supported in the internal space (24) and has a large diameter portion (26) and a small diameter portion (27) smaller in diameter than the large diameter portion (26).
And an engaging portion (28) protruding from the case (21), and the engaging portion (28) is fixedly attached to the other of the keyboard lid (13) and the keyboard instrument body (12). The viscous body (29) is interposed between the case (21) and the large diameter portion (26) and imparts viscous resistance force to the rotation of the shaft (25). The spring (33) is freely wound around the small diameter portion (27), and both ends thereof are fixedly attached to the case (21) and the shaft (25), respectively.

<Operation> When the keyboard lid opening / closing device of the keyboard instrument according to the above configuration is rotated to move the keyboard lid from the open state to the closed state, the coil spring has a restoring force that gradually increases as the rotation angle of the keyboard lid increases. Generate. At the initial stage of rotation of the keyboard lid, the relative speed between the case and the shaft is relatively small, so the braking force due to viscous resistance is also relatively small, but at the end of the rotation, the relative speed between the case and shaft is large. As a result, the braking force due to the viscous resistance also increases, and the keyboard lid quietly reaches the closed state. Therefore, the keyboard lid starts to rotate with a relatively small force in the initial stage of rotation, and as the keyboard lid approaches the closed state in time, the keyboard lid does not need to be supported by a player or the like with a large force. Without hitting the instrument body,
Quietly closed. Moreover, since both ends of the coil spring are fixed, a restoring force corresponding to the rotation angle can be stably generated.

At the same time, since the coil spring is wound around the outer peripheral surface of the shaft with some play, it is possible to substantially eliminate the generation of noise due to these frictions.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 3 is an exploded perspective view of an embodiment of the present invention, in which 11 is a keyboard, 12 is one of the arms provided on both sides of the keyboard,
Reference numerals 13 denote keyboard lids, respectively. Rotary dampers 14 and 15 which will be described later in detail are embedded in the keyboard lid 13, and the rotary damper 14 (15) is inserted into a pivot plate 16 fixed to the arm 12 and its rotation is restricted.
As shown in FIG. 4, the keyboard lid 13 is placed at a position deviated from the center of rotation of the rotary dampers 14 and 15 so that the weight 1
7, for example, a lead plate is embedded, and these weights 17
Urges the keyboard lid 13 to the open state.

Since the rotary dampers 14 and 15 have the same structure but only the acting directions of the springs are different, only the rotary damper 15 will be described with reference to FIGS. 1 and 5. In the figure, 21 is a cylindrical case having a semi-circular plate-shaped flange 22, and the side opposite to the flange of the case 21 is the lid body 2.
It is closed at 3. Therefore, the internal space 24 is defined in the case 21, and the shaft 2 is formed in the internal space 24.
5 is rotatably supported by the case 21 and the lid 23. The shaft 25 has a large diameter portion 26, a small diameter portion 27, and an engaging portion 28 protruding from the case 21, and grease 29 as a viscous body is applied between the large diameter portion 26 and the case 21. ing. Since the O-rings 31 and 32 are attached to the large diameter portion 26 so that the grease 29 does not flow out from the large diameter portion 26, the grease 29 stays between the large diameter portion 26 and the case 21 and will be described later. Generates braking force due to viscous resistance. On the other hand, a coil spring 33 is wound and inserted in an internal space defined between the small-diameter portion 27 and the case 21, and the coil spring 33 is fixed to the shaft body 25 at one end and at the other end. It is fixed to the lid 23. As a result, when the lid body 23, and thus the case 21 and the shaft body 25 rotate relative to each other, the coil spring 33 twists to generate a restoring force. On the other hand, the engagement portion 28 is chamfered as shown in detail in FIG. 5, and the chamfered engagement portion 28 is clamped by the pivot plate 16 described above. Further, a mounting hole 34 is formed in the flange 22, and a rotary screw 15 (1) is inserted by a wood screw or the like (not shown) inserted into the mounting hole 34.
4) is fixed to the keyboard lid 13.

Next, the operation will be described. When the keyboard lid 13 is in the open state, it is stably retained in the open position by the restoring force generated by the weight body 17. Next, when the keyboard lid 13 is rotated toward the closed position, the restoring force of the weight body 17 continues to work in the initial stage, so that even if the operator does not support the entire weight of the keyboard lid 13, a relatively small force is applied. The lid can be rotated with.

Eventually, when the keyboard lid 13 reaches an intermediate position between the open position and the closed position, the torsion of the coil spring 33 increases, the restoring force resulting from the elastic force increases, and the force (rotational moment) resulting from the weight of the keyboard lid 13 increases. ) Is canceled out, the force that the keyboard lid 13 tends to close can be relaxed.

Eventually, when the keyboard lid 13 approaches the closed position, the rotational moment of the keyboard lid 13 increases, and the rotational speed of the keyboard lid 13 increases. As a result, the relative speed between the case 21 of the rotary dampers 14 and 15 and the shaft body 25 increases, and the viscous resistance generated by the grease 29 also increases. Therefore, the keyboard lid 13 is decelerated by the braking force caused by the viscous resistance, and gently abuts on the mouth stick (not shown) that constitutes the musical instrument body.

<Effects> As described above, in the keyboard lid opening / closing device according to the present invention, the spring generates a restoring force to support the weight of the keyboard lid at the beginning of the rotation of the keyboard lid, and at the end of the rotation. , The braking force caused by the viscous resistance of the viscous body gently contacts the keyboard instrument body. As described above, in the keyboard lid opening / closing device according to the present invention, the friction between the solids is not used for generating the braking force,
Friction noise does not occur during braking (closed), enabling smooth and quiet operation. As a result, it is possible to obtain the effect that the performer or the owner does not feel the noise uncomfortable.

Further, since both ends of the coil spring are fixed, there is an effect that a restoring force corresponding to the turning angle of the keyboard lid can be stably generated. For example, if the opening angle of the keyboard lid is 30 degrees, a predetermined elastic restoring force corresponding thereto is generated, and if the opening angle is 60 degrees, a predetermined elastic restoring force corresponding thereto is always generated by the coil spring.

[Brief description of drawings]

1 is a sectional view of a rotary damper used in an embodiment of the present invention, FIG. 2 is a sectional view of a rotary damper proposed in the prior application, and FIG. 3 is an exploded perspective view of the embodiment of the present invention. 4 is a perspective view of a keyboard lid used in one embodiment of the present invention, and FIG. 5 is a perspective view of a rotary damper used in one embodiment of the present invention. 11 ... keyboard, 13 ... keyboard lid, 14,15 ... rotary damper, 21 ... case, 24 ... internal space, 25 ... shaft (shaft body), 26 ... large diameter part, 27 ... small diameter Part, 29 ... Viscous material (grease), 33 ... Spring (coil spring).

Claims (1)

[Claims] 1. A keyboard lid opening / closing device for a keyboard instrument, wherein the keyboard lid opening / closing device has a rotary damper (15), and the rotary damper (15) extends in a direction of closing the keyboard lid (13). A resistance force is generated against rotation, and the case (21), the shaft (25), and the viscous body (29).
And a coil spring (33), the case (21) is fixedly attached to either the keyboard lid (13) or the keyboard instrument body (12), and has an internal space (24), The shaft (25) is rotatably supported in the internal space (24), and protrudes from the large diameter portion (26), the small diameter portion (27) smaller than the large diameter portion (26), and the case (21). Engagement part (2
8), and the engaging portion (28) is fixedly attached to the other of the keyboard lid (13) and the keyboard musical instrument body (12), and the viscous body (29) includes a case (21). The coil spring (33) is interposed between the large diameter portion (26) and imparts viscous resistance to the rotation of the shaft (25), and the coil spring (33) is freely wound around the small diameter portion (27). Both ends are case (21) and shaft (25)
A keyboard lid opening / closing device for a keyboard instrument, which is fixedly attached to each.