JPS6039912Y2 - Upright piano fall prevention device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an overturn prevention device that can prevent an applied piano from overturning in the event of an earthquake.

Applied pianos generally have a side profile as shown in Figure 1, with a height H of about 1,100 to 30 mm, a front-rear depth of 500 to 700 mm, and a horizontal width of 1 when viewed from the front.
．． It is about 500771771 and weighs 200kg.
There is a before and after.

In addition, the center of gravity O is located almost at the center when viewed from the front, but it is slightly rearward in the front-rear direction, slightly above the center in the height direction, and the forward overturning angle φ1 (from the center of gravity O to both sides of the front The angle between an imaginary line crossed perpendicularly to the line connecting the center of caster C and the vertical line varies depending on the model, but is approximately 250, and the rear tipping angle φ2 does not vary depending on the model, but is constant at approximately 13°. are doing.

In order to prevent damage to the floor surface and movement of the piano body P, an insulator a or floor plate made of wood or hard synthetic resin is placed on the floor surface, and the piano body P is placed on top of it by placing casters C or preparations. It is normal to install

By the way, speaking of the problem of shaking of the piano body P during an earthquake, etc., the floor acceleration is A.

In this case, if the coefficient of friction between the floor surface and the piano body P is μ, then
The frictional force F that the piano body P receives from the floor is F≦μW, where gravity is W, and this couple is a force F in the opposite direction.
acts on the center of gravity O.

Then, gravity O acts vertically downward on the center of gravity O.

In this case, Fcosφ)Wsinφ, i.e.);')
If tanφ, the piano main body P will float and swing with one end as a fulcrum.

If F=μW, then μ)tanφ, and therefore,
In order for the piano body P not to swing or fall over, μ(t
It must be anφ.

However, as mentioned above, applied pianos generally have small backward overturning angles φ2 and forward overturning angles φ1, and the insulators a and floor plates that conventionally support the piano body P have a relatively large coefficient of friction, so that the peripheral corners touch the floor. Because they are easily caught and difficult to move, they tend to sway during earthquakes, and there is a risk of them falling backwards or forwards in the event of a large earthquake like the Miyagi earthquake.

Therefore, in order to prevent the piano body P from tipping over due to the horizontal shaking of the floor surface, (1) Enlarge the tipping angle...lengthen the base or lower the center of gravity.

(2) Weaken the force received from the floor ...Makes it slippery and reduces the coefficient of friction with the floor.

...Provide a dynamic vibration absorbing structure using springs, etc.

(3) Fix to another strong object ...Fix to a wall, pillar, or floor.

etc. are considered to be effective means.

On the other hand, pianos now have an established image as high-class furniture, and their designs generally remain the same, so even if the above measures are taken, the image as high-class furniture will be damaged. It must be inexpensive, without causing any damage to the piano body.

This idea was devised in view of the above circumstances, and was designed to expand the falling angle and reduce the force received from the floor without damaging the appearance of the piano body and preventing scratches. The present invention provides a fall prevention device.

To explain the embodiment with reference to the drawings, in Fig. 2, reference numeral 1 denotes a bottom plate, which is longer than the depth of the piano main body P and has a width that allows the front and rear casters C to be placed on it. The portion 1a and the lower edge are arcuate and curved, and a friction reducing member 2 with a small friction coefficient such as tetrafluoroethylene resin is provided on the lower surface of both arcuate ends 1a.
It's stuck on so it's slippery.

On one end, there is a horizontal piece 3a and an upright piece 3 of the required height.
A stay 3 consisting of a side piece 3b and a side piece 3c is fixed thereto, and a plurality of screw insertion holes 4 are provided in the upper and lower parts of the upright piece 3b.

Two of these bottom plates 1 are used as a pair, and casters C on both sides of the piano body P are placed on the bottom plates 1 as shown in FIGS. 4 to 6, and the upright pieces 3 of each stay 3 are
b are brought into contact with both side supports 5 and base 6 on the back side of the piano main body P, respectively, and wood screws are inserted into these screw insertion holes 4 to fix the bottom plate 1 integrally with the piano main body P as shown.

By doing this, the bottom plate 1 does not get caught on the floor surface f due to the arcuate lower surfaces at both ends, and the friction reducing member 2 with lubricity provided thereon makes it easy to slip, so it can be easily used in the event of an earthquake. The force received from the floor surface f can be reduced, and since the length of the floor plate 1 is longer than the depth of the piano body P, the overturning angle φ1 with respect to the center of gravity O can be reduced.
．． φ2 becomes larger, and the piano main body P can be placed in a state where it is difficult to fall over.

In addition, although the front side of the piano body P is usually coated with high-quality paint such as polyester or polyurethane, since the bottom plate 1 is not attached to the front side and is fixed on the back side where no paint is applied, the piano body P Since it does not damage the piano in any way and has the same appearance as a conventional floor plate, it has the effect of detracting from the image of the piano and being inexpensive.

Note that even if rollers 2' are used as friction reducing members at both ends 1a of the bottom plate 1 as shown in FIG. 3, the function remains the same.

[Brief explanation of the drawing]

Figure 1 is a side view of the conventional installed state of an applied piano. FIG. 2 is a perspective view of an example of a floor plate according to this invention. FIG. 3 is a perspective view of a modification thereof. Figure 4 is a side view of the piano with the bottom plate attached. Figure 5 is its back view. Figure 6 is its front view. In the diagram, 1... Bottom plate, 1a
...Both ends, 2...Friction reducing member, 3
...Stay, 3a...Horizontal piece, 3b.
...Upright piece, 4...Screw insertion hole, 5...
... Support, 6 ... Base, P ... Piano body.

Claims (1)

[Scope of utility model registration request] The lower surface of both ends 1a of the bottom plate 1, which is longer than the depth of the piano main body P and has a required width, is made into an arc shape, and friction reducing members 2, 2' are provided, and the upper surface of one end is provided with a horizontal piece 3a and an upright piece 3 of the required height.
This overturn prevention device for an applied piano is constructed by attaching a stay 3 consisting of a side piece 3b and a side piece 3c, and fixing the upright piece 3b of the stay 3 to a support 5 and a base 6 on both sides of the back surface of the piano body P.