JPS6026397A - Finishing of jack head for piano action - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing the head of a jack in a piano action.
This made it possible to abolish what had previously been done.

Jack performs a very important movement in piano action. In other words, the jack is rotatably attached to the wippen, and the key presses include J and <.

With the upward movement of the wippen, it moves -V, and in the up lie 1 heavy piano, it pushes up the rose 1~ff'# Q 'l
! , through the hammer shank to the rose 1 of ξ 9
Try to hit the strings with a hammer that has been removed.
There is. In addition, on a grand piano, the jack pushes up the hammer attached to the hammer shank and strikes the strings with the hammer attached to the tip of the hammer shank. (b' 6 a) In this way, Jack is operating at the 1st position of the important device of the action, and it has a crowding effect on the key presses.Jack makes sure that Rose 1~ Push up and rotate!
Therefore, when the key is released, it quickly enters the bottom of the butt (or hammer roller ~) and the next key is pressed.
As shown in the figure, the front of the head of a conventional jack/I (the case of a grand piano is exemplified) has a chamfered edge 1a of approximately 0.5R, and an upper front 1C, a top surface 1b, and a front surface. Graphite (such as graphite) 2 is coated over the upper part] and the abutment 1a, so that the opening [1 part] is moderately smooth so that its coefficient of friction does not change over a long period of time.

However, there is a Sue on the other side that comes into contact with Ji (Tsuku 40 head).
Nin (ba-ntskin for upright pianos,
Grand pianos have roller skins attached to them, so with long-term use the graphite peels off and the wood itself forms on the surface, creating a high coefficient of friction that can cause noise and reduce the feel of the keys when pressed. It is famously declining.

In addition, FIG. 1 is a perspective view of a material board 1 for manufacturing the main body of a jack for a grand piano, and the front side -1 of this material board 1 is
Apply paper to edge 1a and tighten this area by approximately 0.5R.
J: Sea urchin, front side 1 part 1 (not shown in Figure 2)
Apply graphite 2 over the top surface 1b of the paper (J) and part of the edge 1a of the paper (J), then cut it vertically at the required intervals as shown by the chain line P, and jack it as shown in the third figure. Obtain a main body 3, form fiI'i3 a in the lower part thereof,
As shown in FIG. 4, a separately machined heel 4a is attached to the jack main body 3 by inserting /υ to complete the jack 4.

This invention is based on the above-mentioned j:U [Koji I knock 1111
Instead of applying graphite to the part, press the head of the jack (or the cable (corresponding to the head of the jack in the Δ board stage 83) against the rotating metal body to apply graphite to this part. Compression deformation hardens in the shape C1 It exhibits exactly the same performance as a conventional jack that has just been coated with graphite, and this is one thing that can maintain its initial performance for a long period of time compared to the conventional one. An example thereof will be illustrated and explained below.

In FIG. 5, 5 is a metal body that rotates around a shaft 5b and has a constricted portion 5a in the center. The shape of this constricted portion 5a is the shape of the head of the jack 4 to be completed, and is shown in FIG. Of course, after cutting this wood board 1 lengthwise and placing it in the J-jack main body 3 shown in FIG.゜ Fig. 6 is a perspective view of the wood board 1 whose head has been compressed and deformed by the decoy shown in Fig. 5, and is cut into J: sea urchin pieces at required intervals as shown by chain lines 1). In the end, it becomes Ji 1 Knock 4. Like this 67i
Flush 1: The surface of the head compressed and deformed by the rotating metal body 5 over the part 1C (1 part surface 11) and the front part (1 part edge 1a) is the book jff! The string was broken and compressed and hardened, and the rotating metal body 5 made the exterior surface very smooth, so there was no need to apply graphite 2 at all.

According to the present invention, the head of the jack or the head of the raw material plate that will become the jack is pressed against a rotating metal body, and the head is compressively deformed. The surface of the head becomes extremely smooth after being cured under a pressure of 51 ii, and the conventional graphite coating is no longer suitable.
ζThe effect that il[fil: is maintained can be obtained 1).

4, f” in the drawing, !’, Ai TiJ, !
A perspective view of the material board for manufacturing the 7-piece, Figure 2 (, 1) A perspective view of the head of the material board shown in Figure 1 with graphite applied, Figure 3.
The figure is a perspective view of the jack body, FIG. 4 is a perspective view of an example of a completed jack, FIG. 5 is a side view for explaining the press compression deformation process according to the present invention, and FIG. FIG.

1a...Front 1 part edge 1h...Top surface 1C・・・・・・Part on the front ４・・・・・・・・・Jack 5・・・・・・Rotating gold Ji bar body 5a... Constriction patent applicant

Claims (1)

[Claims] Narrow portion 5a of metal body 5 that rotates front upper part 1C, top surface 11) and front edge 1a in the head of jack 40
A method of finishing a jack head in a piano action by pressing, compressing, deforming, and hardening the front upper part 1C, top part 1h, and front upper edge 1a in the head of the jack 4 into a desired shape.