JP2004151663A - Shifting device for piano - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make lightly and smoothly shiftable a keyboard and an action assembly. <P>SOLUTION: In the piano shifting device in which a frame to which the keyboard 1 and the action device body are fitted is slidably set on a keybed 3, permanent magnets 23, 24 are respectively embedded in the keybed 3 and a back rail 6 of the frame so that both poles are faced each other on the same surface as the opposite surfaces of both the members 3, 6. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piano shift device which can be applied to either a vertical or flat piano and is improved so that a keyboard and an action device body can be smoothly shifted.
[0002]
[Prior art]
As shown in FIGS. 1 and 2, the conventional general piano has a keyboard 1 and an action device body (string-striking device) in which only the action base 2 is shown on the shelf 3.・ A push-up bar 8 and a bell-crank-shaped lever 9 mounted on a frame (keyboard か ら) composed of three rails (筬) 4, 5, 6 and Tsumaki 7 etc. Thus, the frame is slid in the left-right direction, and a required shift is achieved. In this structure, the middle rail 5 is supported by a contact 11 at a plurality of locations and slightly lifted from the upper surface of the shelf board 3, but the front rail 4 and the back rail 6 are respectively supported by the guide rollers 12 on the opposite surface side. It floats slightly from the upper surface of the shelf board 3, and the opposite side portions are in contact with the upper surface of the shelf board 3.
[0003]
The guide roller 12 is supported on the free end side of the adjustment plate 15 mounted on the shelf plate 3 using a pair of wood screws 13 and 14, and is lifted on the opposite surface portion side of the front rail 4 and the back rail 6 (shelf plate 3 Can be adjusted. That is, the adjusting plate 15 is curved in a shallow concave shape between the wood screw 13 and the wood screw 14, and the lower surface of the curved portion 15 a is applied to the head of the receiving screw 16 embedded in the shelf plate 3, and the head (shelf plate 3 The free end side of the adjustment plate 15 is raised and lowered by a loosening operation of the wood screws 13 and 14 with the 16a (which is flush with the upper surface of the plate) as a fulcrum. By adjusting, the front rail 4 and the back rail 6 can slide smoothly.
[0004]
In the figure, 17 is a shift roller attached to the driven side end of the lever 9 with respect to the pivot 18 of the lever 9, and the shift roller 17 can rotate on the fitting portion 19 provided on the side surface of the back rail 6. Is attached to. Reference numeral 21 denotes a return spring that acts on the push rod 8 side, and 22 is a return spring that acts on the back rail 5 side. In the illustrated case, the action base 2 is mounted on the back rail 6, but depending on the type of piano, there are some that are provided across the middle rail 5 and the back rail 6.
[0005]
[Problems to be solved by the invention]
In such a conventional device, since the weight of the action device body is borne by the back rail or the back rail and the middle rail to which the action device body is assembled, the back rail, which is partially in contact with the shelf, The frictional force with the plate is large, causing heavy resistance to pedal operation and causing a sense of resistance, as well as causing factors such as rattling and deviation between related members. The present invention solves such a problem, and its purpose is to provide an apparent buoyancy to the back rail by utilizing the repulsive force between the permanent magnets so that the shift operation is light and smooth. An object of the present invention is to provide a piano shift device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a piano shift device characterized by the present invention is a piano shift device in which a frame in which a keyboard and an action device body are assembled is slidably set on a shelf board. Permanent magnets are embedded in the rear plate of the shelf and the frame so that the same poles face each other on the opposite surfaces of the two members. In this configuration, the permanent magnets are preferably embedded at a plurality of positions on the shelf board and the back rail (preferably at equal intervals) from the viewpoint of the stability of the shift operation.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the following, an embodiment of the present invention will be described with reference to FIGS. In addition, the previous description by FIG.1, 2 is used and this invention is demonstrated using the same code | symbol about the same member as the member in the description. In a piano shift device in which a frame to which a keyboard 1 and an action base 2 of an action device body are attached is slidably set on a shelf 3, the shelf 3 and the rear rail 6 of the framework have Permanent magnets 23 and 24 are embedded in a plurality of positions so that the same poles (S and S or N and N) face each other in a state where the opposite surfaces of both members 3 and 6 are flush with each other. The present invention is carried out in such a manner that an apparent buoyancy is given to 6 by the repulsive force of both permanent magnets 23 and 24.
[0008]
In the illustrated case, the permanent magnets 23 and 24 are disk-shaped and are embedded at five positions on the shelf 3 and the back rail 6 at equal intervals, but the shape may be rectangular. Since the apparent buoyancy is given to the back rail 6 in this way, the back rail 6 can reduce the frictional force with the shelf 3 during the shift operation, and the keyboard and the action device body can be shifted lightly and smoothly. it can.
[Brief description of the drawings]
FIG. 1 is a plan view showing a principal part of a piano embodying the present invention with a part cut away.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a cross-sectional view taken along line BB in FIG.
[Explanation of symbols]
1 is a keyboard, 2 is an action base which is a part of the action device body, 3 is a shelf board, 6 is a back rail, and 23 and 24 are permanent magnets.

Claims (2)

In a piano shift device in which a frame to which a keyboard and an action device body are attached is slidably set on a shelf, the shelf and the rear rail of the framework are respectively opposite to the opposing surfaces of the two members. A piano shift device, wherein permanent magnets are embedded so that the same poles face each other in a flush state. 2. The piano shift device according to claim 1, wherein the permanent magnets are embedded at a plurality of positions on the shelf board and the back rail at intervals.

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