JPH0232344Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a circular saw used for cutting solid dry ice. The circular saw of the present invention is used as a large cutting machine in a dry ice manufacturing factory or as a cutting machine for obtaining thin pieces of dry ice. [Prior Art] Generally, solid dry ice is shipped from a manufacturing factory as a cube of about 25 cm on a side, and is used by cutting it into a desired size such as a thin plate shape depending on the purpose. A band saw is usually used to cut dry ice, but recently attempts have been made to develop an efficient and safe cutting device using a circular saw. Conventionally, circular saws have been widely used for woodworking, metal processing, etc., but when these circular saws are used, the saw blade elongates in the outer circumferential direction due to the centrifugal force generated by the rotation of the circular saw, and the saw blade expands due to cutting heat and frictional heat. Due to expansion, the saw blade deforms and becomes difficult to work with. Therefore, a process called ``Koshiiri'', in which the saw blade is slightly expanded and curved by hammering, is applied to the circular saw from the center to about 1/6 of the radius.
It is applied in advance to the saw blades that reach the tips of the teeth, especially the saw blades from 1/3 to 2/3. On the other hand, in the case of cutting dry ice, although elongation due to centrifugal force occurs in the same way, dry ice is at a low temperature of approximately -79°C, so the amount of cooling energy is much greater than the amount of heat generated by cutting and friction.
Deformation occurs due to contraction of the saw blade. Therefore, when cutting dry ice with a circular saw used for woodworking, etc., the circular saw gradually deforms, the cutting path meandering, and the dry ice gets stuck, making it difficult to cut satisfactorily. It was hot. Although means for preventing deformation of circular saws due to thermal expansion have been considered in the past, deformation due to cooling contraction has not been taken into account, and no countermeasures have been known. [Problems to be solved by the invention] The inventors of the present invention have studied how to deal with the deformation of a circular saw due to cooling shrinkage by so-called waist tightening, and have developed a method that focuses mainly on the outer periphery of the circular saw. Through this work, he learned that a circular saw that can withstand low temperatures can be obtained if it is made into a specific shape. In other words, the gist of the present invention is that the part of the saw blade of a circular saw from the center of rotation to a position approximately 2/3 of the radius is curved into a shallow dish shape centered on the center of rotation. The circular saw for cutting dry ice is characterized in that a portion from the to the tip of the tooth is curved in the opposite direction to the above portion with the apex at this position. The circular saw of this invention usually stretches the saw blade by hammering,
It can be manufactured by so-called waist-fitting. In other words, in order to deal with the elongation of the saw blade mainly due to centrifugal force during rotation, it is approximately 1/6 of the radius from the center of rotation.
Extend the saw blade from the position to the tooth tip, then extend the saw blade sufficiently from about 2/3 of the radius to the tooth tip to cope with shrinkage due to cooling. It is important to apply the hammering evenly on both sides of the specified circumferential surface. Hereinafter, the circular saw of the present invention will be explained with reference to the drawings. FIG. 1 is a sectional view of the circular saw of the present invention, and FIG. 2 is a plan view showing an example of the circular saw of the present invention. In the figure, 0 is the rotation center of the circular saw, and a, b, and c are points that divide the distance from the rotation center of the circular saw to the tip of the tooth (circular saw radius) into three equal parts. As the cross section of the circular saw of the present invention is shown in Fig. 1,
The saw blade begins to curve slightly from 1/6 on the plane from the center of rotation to a position about 1/6 of the radius (midway between 0 and c), and from the center of rotation to a position of about 2/3 of the radius, the saw blade curves around 0. It is shaped like a watch glass. From about 2/3 of the radius onwards, it curves in the opposite direction. Therefore, a horizontal plane A that touches a point about 2/3 of the radius and an imaginary surface with a rotation center 0 opposite to the plane (the rotation center is a hole for mounting a circular saw, but it is assumed that there is no mounting hole) distance t from the surface)
varies depending on the diameter of the circular saw. That is, t is in the range of 24/1000 to 26/1000 of the diameter of the circular saw. Also, the distance ε between the surface of the tooth tip and the horizontal plane A is 0.2
~0.4 mm, preferably 0.3 mm. In addition, in this invention, it means the tip of a tooth and the tip of a tooth which does not include a set. In this way, the degree of saw blade is adjusted so that t and ε are set to predetermined values. Table 1 shows examples of the values of t and ε at appropriate rotational speeds for various sizes of circular saws according to the present invention.

[Effect of idea]

The circular saw of this invention is manufactured by a simple operation of mainly extending the saw blade from about 1/6 of the radius from the center of rotation to the tip of the tooth, especially the outer periphery from about 2/3 of the radius. It has excellent performance in that it can continuously cut large amounts of dry ice for a long time without being affected by low temperatures.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a circular saw according to the present invention, and FIG. 2 is a plan view showing an example of the circular saw of the present invention. Symbols in the diagram: 0...Rotation center of the circular saw, 1...Tooth tip, 2...Tooth bottom, 3...Slit, 4...Round hole,
5...Mounting hole, A...Horizontal surface in contact with the circular saw.

Claims (1)

[Scope of claim for utility model registration] (1) Approximately 2/2 of the radius from the center of rotation of the saw blade of a circular saw
The part up to position 3 is curved into a shallow dish shape centered on the rotation center, and the part from this position to the tooth tip is curved in the opposite direction to the above part with this position as the apex. A circular saw for cutting dry ice. (2) When the saw blade is placed on a horizontal plane so as to be in contact with the saw at this position, the distance from the virtual surface of the rotation center opposite to the plane to the plane is 24/1000 to 24/1000 of the diameter of the circular saw. 26/1000, and the distance from the surface of the tooth tip to the plane is in the range of 0.2 to 0.4 mm. (3) A claim for utility model registration characterized in that the part of the saw blade from the center of rotation to about 1/6 of the radius is flat, and from about 1/6 onwards it is curved. The circular saw according to item 1 or 2. (4) Claims 1 to 3 for utility model registration, characterized in that a slit is provided from the bottom of the tooth of a circular saw.
Circular saw described in any of the paragraphs.