JP7061789B2 - Saw blade - Google Patents

Description

The present invention relates to an anti-shake structure in a saw blade of a type that cuts by installing and fixing to a drive source that makes a reciprocating rotary motion with a small amplitude (rotation angle).
In the following specification, the term "reciprocating arc vibration" is used, but it refers to this "reciprocating rotational motion with a small amplitude (rotation angle)".

The saw blade is often either a reciprocating type (typically a hand-grinding saw) or a rotary-moving type (typically a circular saw). Both of them have a large cutting ability, but there is a problem in safety, and there are also chips flying, loud noise, etc., so they are not ideal tools.

Under such circumstances, the following are present as special power tools for cutting.
That is, as shown in FIG. 6, the dedicated saw blade B is installed and fixed to the drive shaft A provided on the tool body. (The tool in the example of FIG. 6 is a tool that can also be used as an electric file or polisher by attaching, for example, a polishing member instead of a saw blade.)
To fix the saw blade to the main body, use a one-touch method in which an elastic claw is provided on the main body side, and the saw blade is locked by the restoring force of the claw by inserting it into the hole provided on the saw blade side in a contracted state and passing it through. There may be various methods such as a method in which a female screw is arranged on the main body side and a saw blade is sandwiched between separate male screws, a method in which a magnet is used in combination, and the like.

This drive shaft A does not rotate in one direction, but has a vibration form in which a reciprocating arc motion (arc vibration) having a very small vibration angle (mostly about 4.0 degrees or less) is performed. When the tool is operated, the entire dedicated saw blade B reciprocates at a small central angle. Strictly speaking, each cutting tooth at the tip of the saw blade B makes a reciprocating circular motion, but since the angle is small, it looks like a linear reciprocating motion in a pseudo manner. In addition, because the amplitude is small, it is completely different from the behavior of a general powered reciprocating saw, and is similar to the vibration of a vibrating electric shaver.
The cutting work using this tool simply presses the saw blade straight against the wood, which results in the formation of slit holes in the board. The saw blade found in Japanese Patent Publication No. 2000-512561, which is shown as a prior art document, basically has a structure similar to that of the dedicated saw blade B.

By the way, it is possible to form a slit hole even by using a conventional hand-held round blade saw. However, since the saw blade tries to cut by continuing to rotate in one direction, the saw blade basically tries to roll on the wood to be machined. Therefore, while withstanding this rolling force, a narrow through hole is first created, and the width is widened to obtain a predetermined dimension. Unlike this tool, which only requires pressing straight in the thickness direction of the wood, it is of course necessary to learn the work procedure. In the case of a circular saw, chips are ejected from the slit hole during cutting at a considerable initial speed and scattered, which has been pointed out as a problem of deterioration of the working environment. That is, it can be said that it has various problems other than the high risk.

Special Table 2000-512561 Gazette

The method of cutting by utilizing "arc vibration" has such an advantage, but when the cutting work is actually performed using the dedicated saw blade B, the vibrating saw blade cannot be controlled and is covered. It is not uncommon for the surface of the work piece to become rough or to start cutting at the wrong position by dancing on the work piece (wood).

Therefore, the present inventor has finally made the present invention as a result of diligent research in view of this point, and the feature thereof is a saw blade for an electric saw tool having a drive shaft that vibrates in a reciprocating arc. The front end is provided with a tooth row of cutting teeth, and the rear portion is provided with a connecting hole for connecting to the center of the drive shaft. Only for 1 to 3 cut teeth in the center of the dentition, the height of the cut teeth at the distance between the tooth bottom and the tooth tip is designed to be high, and 1 to 3 cut teeth in the center of these dentitions are designed. It is in the point that it exists in the foremost position.

In the case of a saw blade that vibrates in a reciprocating arc, the angle of rotation is usually about 3 degrees (that is, 1.5 degrees to the left and right) or less, so the amplitude of the cutting teeth is only about 4 mm. That is, it can be said that it is a very safe saw when compared with a general rotary saw (so-called circular saw) or a powered reciprocating saw.

In such a vibration type saw blade, if only 1 to 3 cutting teeth (hereinafter referred to as central cutting teeth) in the center of the dentition of the cutting teeth are designed to be higher than other cutting teeth, the tooth bottom line. If is a straight line or a curved line or a folded curve that bulges toward the work piece, the central cutting tooth will pierce the work piece (wood) first.

The "height of the cut tooth" is defined as the distance from the root of the cut tooth to the tip of the tooth. The tooth bottom refers to a portion corresponding to the valley bottom of a V-shaped (some have a rounded valley bottom and a U-shaped shape) cut by sharpening. Apart from this sharpening work, there is also a saw blade that intermittently provides a slit groove to help discharge sawdust, but for the present invention, the bottom of this slit groove is used when calculating the "height of the cutting tooth". It shall not be a standard.

On the other hand, it is also common to express the cut tooth that first comes into contact with the work piece as the "tallest cut tooth", and the "height" in this expression is the "height of the cut tooth" in the present specification. The concept is different from. Therefore, in order to clarify these differences, the direction of digging by cutting is called "forward", and the direction in the opposite direction is called "rear". Therefore, if the central cutting tooth is in the foremost position, the central cutting tooth first touches the work piece.

In other words, the height of the central cutting tooth is higher than that of other cutting teeth, and it is not synonymous with the central cutting tooth that first comes into contact with the object to be cut during the cutting operation.
Further, in the present invention, it is an essential requirement that the central cutting tooth first comes into contact with the object to be cut during the cutting operation, so that the central cutting tooth needs to be located in the foremost position.
Therefore, in reality, the central cutting tooth is positioned in the foremost position by making the tooth bottom of each cutting tooth bulging forward or horizontal.

In the case of the saw blade according to the present invention, the cutting is not started from the state where a large number of cutting teeth are in contact with the workpiece all at once, but the cutting is started after the central cutting teeth are pierced first. Compared to the case where the tooth is pierced, the phenomenon called saw blade dance that occurs when the object is first hit with the work piece is almost eliminated. Perhaps the reason is that if the number of cutting teeth is very small, 1 to 3, all the force that presses the saw against the object to be cut is concentrated on these 1 to 3, and compared to the case where a large number of teeth are used, 1 This is probably because the force received by the book increases and it becomes easier to pierce. In addition, when another cut tooth hits the surface of the material after one or three cut teeth have previously entered the material, these already inserted cut teeth support the lateral force of the dentition, thereby supporting the other. It seems that the unfavorable behavior of the cut teeth can be regulated.

If the height difference between the central cutting tooth and the other cutting teeth is too small, for example, if the surface smoothness of the work piece is low, both the central cutting tooth and other normal cutting teeth can come into contact with the work piece. It is sexual and ineffective. In addition, the central cutting tooth is to prevent the tooth from dancing in the initial stage of cutting work, but it is also present even when the cutting operation is in full swing after the initial stage, so the height is high. If the difference is too large, the cutting hole will precede only the central part, and the load on the central cutting tooth will increase, causing wear and breakage to concentrate here.
In consideration of these, it is preferable that the height difference is 0.5 mm or more and 2.0 mm or less.

The present invention is not particularly limited to the method of changing the height of the central cutting tooth and the other cutting teeth. For example, the "pitch" (described later) of the cutting tooth may be designed to be large only in the central cutting tooth portion, or the upper grain processing of the central cutting tooth portion may be reduced or omitted. In particular, when the central cut tooth is formed by sharpening the cut tooth at a large pitch, it is effective because it is easy to maintain the strength.

In the saw blade, the "pitch of cutting teeth" is often expressed by "the number of tooth tips existing in one inch" or "the length of the dentition formed by the reference number of cutting teeth".
However, in the present invention, the cutting tooth height is increased only for one to three central cutting teeth, and as a structure for increasing the cutting tooth height, a method of increasing the entire central cutting tooth at the initial stage of sharpening is used. , It includes both a method of increasing the cutting tooth height by reducing the cutting amount at the time of upper stitch processing without increasing it at the initial stage, and it cannot be described by the conventional pitch expression method. ..
Therefore, in the present specification, the “cutting tooth pitch” is the distance between the midpoint C of the tooth bottom of the cutting tooth and the midpoint C of the tooth bottom of the adjacent cutting tooth (this is the midpoint) as shown in FIG. (Called the distance).

Further, although the saw blade is usually provided with a "saw blade", it is not essential in the present invention. Therefore, it is not necessary to provide the asari.

It should be noted that the present invention relates to the structure of the saw blade, and the details of the structure of the tool body for driving the saw blade are not limited. However, the drive form transmitted by the tool body to the saw blade of the present invention is limited to "arc vibration". Therefore, it is inappropriate to apply it to a power tool having a drive form such as a linear reciprocating motion such as a hand saw or a unidirectional rotary motion such as a circular saw.

The saw blade according to the present invention is a saw blade for an electric saw tool having a drive shaft that vibrates in a reciprocating arc, and is for connecting to the tooth row of cutting teeth at the front end and to the center of the drive shaft at the rear end. A connecting hole is provided, and for the 1 to 3 cut teeth in the center of the tooth row at the front end, only the 1 to 3 cut teeth in the center of the tooth row at the front end are the distance between the tooth bottom and the tooth tip. It is characterized by the fact that the height of the cutting teeth is designed to be high, and that 1 to 3 cutting teeth in the center of the tooth row are present at the frontmost position, and the number of teeth is small immediately after the start of cutting work. This is an extremely advanced invention that has the effect of being able to cut as desired without the teeth dancing because the central cutting tooth pierces the work piece in advance and this causes a reciprocating arc movement within the work piece.

It is a schematic plan view which shows an example of the saw blade which concerns on this invention. (A) and (b) are schematic plan views which show an example of the saw blade which concerns on this invention. (A), (b), and (c) are schematic plan views showing the outline shape of the cutting tooth of an example of the saw blade according to the present invention. (A) and (b) are schematic plan views which show the outline shape of the blade part of the saw blade which concerns on this invention. It is a schematic plan view which shows the other example about the cutting tooth shape of the saw blade which concerns on this invention. It is a top view which shows the electric saw tool which installs the saw blade which concerns on this invention, and the conventional example of the saw blade which was attached to this. It is a schematic plan view for demonstrating the pitch of a cutting tooth.

FIG. 1 is a plan view showing an example of a saw blade 1 according to the present invention (hereinafter referred to as “the saw blade 1 of the present invention”). The saw blade 1 of the present invention is a saw blade attached to a tool having a drive shaft having a property of arc-vibrating (for example, the tool shown in FIG. 6), and is connected and fixed to the drive shaft of the tool by a connecting portion 2. .. Further, the blade 3 composed of a large number of cutting teeth 31 is provided at the end portion on the opposite side to the connecting portion 2.
In the case of this example, the central angle of the arc vibration is 1.6 degrees.

2 (a) and 2 (b) show two examples of the blade portion of the saw blade 1 of the present invention. The figure (a) shows an example in which the Higaki sharpening is applied, and the figure (b) shows an example in which the Higaki sharpening is not performed and the blade has a chevron shape. The cutting teeth 31 are provided in a row, but their heights are not constant, and only one in the center protrudes. In this example, the protruding central cutting tooth 311 has a cutting tooth pitch larger than that of the other cutting teeth 31.
In this example, the number of central cutting teeth 311 is only one, but two or three may be used.

The general shape of the cutting tooth 31 of the blade 3 is not limited to the horizontal (straight line) shape as shown so far, and may have various forms. FIG. 3 shows an example other than horizontal, in which FIG. 3A is an arc-shaped example, FIG. 3B is a V-shaped example, and FIG. 3C is almost horizontal and left and right. An example in which only the vicinity of the edge is lowered is shown. And there may be other forms.

Further, the shape of each cutting tooth 31 may be directional (asymmetrical) like a normal saw-tooth, but may be non-directional (symmetrical). .. FIG. 4 shows this, and FIG. 4A shows an example with directionality, and FIG. 4B shows an example without the same. Further, the present invention does not limit whether or not each of the cut teeth 31 has a structure called Edo-me, in which an upper eye (a tooth tip cut with a file) is provided. That is, the processing of the upper stitch may be omitted (not shown).

FIG. 5 is an example in which the distance (pitch) between the midpoints of the central cutting tooth 311 is the same as that of the other cutting teeth. In this example, in order to increase the cutting tooth height (separation distance between the tooth bottom and the tooth tip) of the central cutting tooth 311, the upper grain processing applied to the cutting tooth tip is made different in the central cutting tooth 311 part. It is a thing. As a result, the cut portion 4 due to the superorder processing is extremely small in the central cutting tooth 311. This method has the effect of being easy to manufacture because most of the dressing process can be performed by the conventional method (only the upper grain processing is different).

1 Saw blade according to the present invention 3 Blade 31 Cutting tooth 311 Long large cutting tooth 2 Connecting part 4 Cutting part by upper grain processing A Drive shaft B Dedicated saw blade (conventional product)
Midpoint of the root of the C cut tooth

Claims (3)

A saw blade for electric saw tools that has a drive shaft that vibrates in a reciprocating arc.
At the front end is a dentition formed by multiple cut teeth ,
The rear part is provided with a connecting hole for connecting to the center of the drive shaft.
The roots of all the cutting teeth provided on the saw blade are provided so as to be located on a straight line.
Of the plurality of cut teeth, for 1 to 3 cut teeth in the center of the front end tooth row, only the 1 to 3 cut teeth in the center of the front end tooth row are the distances between the tooth bottom and the tooth tip. The height of the cut teeth is designed to be high, and 1 to 3 cut teeth in the center of these dentitions are located in the foremost position.
A saw blade characterized in that the difference between the cutting tooth heights of 1 to 3 cutting teeth in the center of the dentition and the cutting tooth heights of other cutting teeth is 0.5 mm or more and 2.0 mm or less . The pitch of the cutting teeth, which is the tooth tip spacing from the adjacent cutting teeth, is large only for the central 1 to 3 cutting teeth, and the pitches of the cutting teeth other than the central 1 to 3 are evenly spaced. The saw blade according to claim 1. The saw blade according to claim 1, wherein the pitches of all the cutting teeth are evenly spaced with respect to the pitch of the cutting teeth at the tooth tip spacing from the adjacent cutting teeth.

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