RU69673U1 - BELL - Google Patents

Abstract

The utility model relates to acoustics and can be used in musical instruments, church bells.

The bell contains a housing with slots and a striker, while the slots are made in the form of perforated holes located at a height from the cut of the bell, equal to 0.35-0.9 of the maximum radius of the bell.

A bell may contain at least four holes. The holes are arranged in one or more rows, each of which is parallel to the cut of the bell.

The utility model can be used to improve the acoustic characteristics of percussion musical instruments.

Description

The utility model relates to acoustics and can be used in musical instruments, church bells.

A known construction of a bell used as a percussion sound instrument, comprising a sound generating element in the form of a bell housing and a drummer fixed to the swing body inside the bell housing. In this case, the housing is made hollow with an open inner shell, a hole is made in its upper part (RU 98116322 A).

In addition, a bell is known in which, in order to replace the expensive bell bronze with cheap aluminum alloys, gaps were made in the body of the mantle (US patent No. 4619846).

The closest in technical essence and the achieved effect is the bell of V.F. Pankratov, described in RF patent No. 1794259, published on July 2, 1993. For a pleasant timbre and tonality in the bell case from the flange side (edges of the bell case), shaped slots are made in the form zigzag. Slots in an amount of 2 to 4 have a depth of ¼ of the body height to 2/3. Slots divide the flange into 2-4 parts. Curly slots in their directions extend from the edge of the bell into the hook and go exclusively parallel to the longitudinal axis of the bell.

Known bell has the following disadvantages. Deep zigzag slots significantly reduce the mechanical strength of the bell. A bell of known design cannot be made of cast iron, brittle material, but only, based on the description of the prototype, from steel or brass. In addition, the manufacture of zigzag slots in strict parallel axis

bells on large bells are a technologically laborious operation.

The objective of the utility model is to develop the design of the bell, which has improved acoustic characteristics, made of both steel and non-ferrous metals, and cast iron. Moreover, the design has sufficient mechanical strength and can be made both in the form of small bells, and in the form of large bells.

The problem is solved by the claimed utility model, in which a bell containing a body with slots and a striker has slots made in the form of perforated holes located at a height from the cut of the bell, equal to 0.35-0.9 of the maximum radius of the bell.

In this case, the bell may contain at least four holes.

Perforated holes can be located on the body more than one row parallel to the cut of the bell.

The inventive bell is shown in Fig.1-3.

The bell contains a housing 1, a hammer 2. On the side surface of the housing 1 are perforated holes 3. The bell may contain one row of perforated holes (figure 1) or more than one, for example, two rows (figure 2), three rows (figure 3 )

As a sample, a bell was made of gray cast iron SCh21-40. The main dimensions of the cast-iron bell are as follows:

- maximum diameter (at the cut) - 0.256 m;

- external height - 0.197 m;

- internal height - 0.18 m;

- weight - 6 kg.

On the surface of the bell, holes are made by any known method, for example, drilled or milled. All this is done already on the cast bell.

The height of the perforated holes, comprising 0.35-0.9 of the maximum radius of the bell, was chosen based on the following. The oscillations of the bell in its upper part (at the shoulder) are insignificant, and the effect of perforated holes on the mechanical strength while ensuring good acoustic characteristics of the bell is also small. The location of the holes in the region of the sound ring closer to the cut of the bell will significantly weaken the mechanical strength of the product, because it is in this place that the bell experiences the greatest fluctuations. Therefore, the perforated holes are located in the middle part of the bell at a distance of 0.35-0.9 from the maximum radius of the bell.

The bell contains at least four holes. The number of holes is selected based on the fact that to provide good acoustic characteristics, including large in size, designs. The number of holes should correspond in each particular product to the number of meridian nodal lines of the bell. In this case, the diameter of the holes was chosen so that it was maximum, but at the same time, did not exceed the distance between the holes (jumper width).

To confirm the acoustic characteristics of the bell, some bell sound parameters were taken.

As the main acoustic characteristics were taken:

- the frequency spectrum of the bell at the time of impact;

- the frequency spectrum of the bell with a steady tone;

- frequency diagram of sound attenuation over time in three-dimensional measurement;

- sound attenuation diagram over time for the entire frequency spectrum;

- diagram of sound attenuation over time for the lowest and longer-sounding overtone (non-interton).

Acoustic characteristics were measured using standard equipment. Acoustic data processing was carried out by computer programs. Measurements showed that the number of holes affects the frequency characteristics of the sound of the cast-iron bell, as well as the decay time of the bell. When the holes were arranged in one row, the presence of 24 holes had the greatest influence on the spectrum. For two rows - four holes, and for three rows - also 24 holes. As for the decay time, in all cases, the best influence on the duration of the sound had the presence of 4 holes, 8 holes, 24 holes depending on the row. Thus, the arrangement of the openings with more than one row parallel to the cut of the bell gives the cast iron bell improved acoustic characteristics. This is shown in the diagrams in FIGS. 4-7:

- figure 4 - frequency spectrum of the claimed bell at the time of impact;

- figure 5 is the frequency spectrum of the inventive bell with a steady tone;

- Fig.6 is a diagram of the attenuation of sound over time of the bell without holes;

- Fig.7 is a diagram of the attenuation of sound over time of a bell with holes.

As can be seen from the above diagrams (Fig.6 and 7), the presence of perforated holes located in the middle part of the bell at heights of 0.35 and 0.9 from the maximum radius of the bell (Fig.7) gives the bell sound improved acoustic characteristics.

Compared with the prototype, making holes in the form of perforations is technologically simpler. This is especially important for products of large geometric dimensions, especially from brittle material, such as cast iron.

Claims (3)

1. The bell containing the body with slots and the drummer, characterized in that the slots are made in the form of perforated holes located at a height from the cut of the bell, equal to 0.35-0.9 of the maximum radius of the bell. 2. The bell according to claim 1, characterized in that it contains at least four holes. 3. The bell according to claim 1, characterized in that the perforated holes are located on the body by more than one row parallel to the cut of the bell.