Cutting – Tool or tool with support – Endless band or belt type
Reexamination Certificate
1997-03-11
2003-03-18
Dexter, Clark F. (Department: 3724)
Cutting
Tool or tool with support
Endless band or belt type
C083S847000, C083S848000, C083S851000
Reexamination Certificate
active
06532852
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a band saw blade, and more particularly to a band saw blade whereby deviation of the cut and noise can be restrained during the cutting of the workpiece.
2. Description of the Related Art
Conventionally, a band saw blade has a left set teeth and right set teeth which are bent to the left and right respectively in the direction of the thickness of the band saw blade (the transverse direction). Hitherto, as one typical example of a band saw blade, there is a band saw blade with a uniform band width and with left set width and right set width which widths are uniform and constant. However, in the conventional band saw blade, cutting resistance increase, so that a deviation of the cut is easily produced. Also, the saw blade will rub against a work-hardening layer formed on the surface of workpiece during the cutting operation, so that noise is produced.
In order to restrain the noise and the deviation during the cutting operation, a variety of band saw blades have been developed which have structures such that the heights, the set width and pitches of the saw teeth are varied.
For example, as disclosed in U.S. Pat. No. 4,195,543, a band saw blade has been disclosed which is formed such that the width of the band portion is constant and a wavy portion is formed in the widthwise direction of the band portion. Another example has been disclosed in U.S. Pat. No. 4,557,172 in which heights of the teeth are made to be different. Other band saw blades have been disclosed in U.S. Pat. No. 4,727,788 and U.S. Pat. No. 4,813,324 in which the heights of the teeth are varied and the set width is enlarged for teeth having low heights. Moreover, a band saw blade has been disclosed in U.S. Pat. No. 5,094,135 in which the back surface is formed into a straight-line shape and a wavy shape is provided such that tooth tips of the saw teeth describe an imaginary curve.
However, when the above-mentioned conventional band saw blades are used to cut workpieces having small diameters which cannot easily be cut, accumulative cut areas are substantially the same even if the band saw blades disclosed in U.S. Pat. No. 4,195,543, U.S. Pat. No. 4,813,324 and U.S. Pat. No. 5,094,135 are used if the material of the tip portion of the teeth of the band saw blade is the same. However, when workpieces having large diameters are cut, the cutting operations using the band saw blades result in remarkable difference.
When the area of workpieces, which have large diameters and which cannot easily be cut, can be cut and the area of workpieces, which have small diameters, can be cut by the band saw blades improved by conventional technology are compared, the areas which can be cut are considerably small in the case where workpieces having large diameters are cut.
Although the back surface and the tooth tip of the band saw blade disclosed in U.S. Pat. No. 4,195,543 are formed into wavy shapes, swarf cannot be fined. Although the band saw blade disclosed in U.S. Pat. No. 4,813,324 is able to fine swarf, the cut length cannot be shortened because the wavy shape is not employed. Although the band saw blade disclosed in U.S. Pat. No. 5,094,135 is able to fine swarf, the structure in which the wavy shape which describes the imaginary curve is formed in only the tooth tip portion attains an unsatisfactory effect to shorten the cut length.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a band saw blade which is capable of realizing similar cut areas regardless of the diameter of the workpieces required to be cut, reducing cutting resistance and restraining deviation of the cut from the cutting line desired and noise generation during the cutting operation.
In order to achieve the foregoing object, according to a first aspect of the invention, there is provided a bad saw blade, comprising: a wavy back surface which is changed periodically or irregularly; and a plurality of tooth groups having tooth tips which substantially describe a plurality of imaginary curves or a plurality of imaginary straight lines running parallel to the back surface.
According to a second aspect of the invention, as it depends from the first aspect, larger set width are provided for tooth groups having tooth tips which substantially describe the imaginary curve or the imaginary straight line near the back surface among the plural tooth groups having the tooth tips which substantially describe the plural imaginary curves or the plural imaginary straight lines far the back surface.
According to a third aspect of the invention, as it depends from the first and the second aspects, tooth groups have tooth tips which substantially describe an imaginary curve or an imaginary straight line farthest from the back surface among the plural tooth groups having the tooth tips which substantially describe the plural imaginary curves or the plural imaginary straight lines running parallel to the back surface are composed of a plurality of straight teeth or a plurality of right and left set teeth or a plurality of straight teeth and a plurality of right and left set teeth, and the tooth groups which substantially describe the other imaginary curves or the imaginary straight lines are composed of a plurality of right and left set teeth.
When a workpiece is cut by the band saw blade according to claims 1 to 3 having the structure such that the back surface which is periodically or irregularly changed is rocked along the backup guide of the band saw blade, the cut length can be shortened even if a workpiece having a large diameter is cut. Since the structure is formed such that the set width is enlarged for the tooth group having the tooth tip which substantially describes the imaginary curve or the imaginary straight line near the back surface, swarf can be fined.
Even if a workpiece having a large diameter is cut, the cut length can be shortened as if a workpiece having a small diameter is cut. Since swarf can be fined, the cutting resistance can be weakened, noise can be prevented, unintentional bending can be prevented during the cutting operation.
According to a forth aspect of the invention, as it depends from the first and the second aspects, tooth groups having tooth tips which substantially describe an imaginary curve or an imaginary straight line farthest from the back surface among the plural tooth groups having the tooth tips which substantially describe the plural imaginary curves or the plural imaginary straight lines running parallel to the back surface are composed of a plurality of straight teeth or a plurality of dovetail set teeth or a plurality of straight teeth and a plurality of dovetail set teeth, and the tooth groups which substantially describe the other imaginary curves or the imaginary straight lines are composed of a plurality of dovetail set teeth.
Since the band saw blade according to the forth aspect of the present invention has the structure such that the right and left set teeth employed in the structure according to the third aspect are changed to dovetail set teeth, basic effects can be obtained similarly to the foregoing structure. However, employment of the dovetail set teeth attains another effect in that the ghost pattern in the cut surface can be reduced significantly and therefore the shape of the cut surface can be improved.
In the construction according to the aspects described above, when a workpiece is cut by the band saw blade, the wavy back surface which is periodically or irregularly changed is rocked along the backup guide. Therefore, the cut length can be shortened even if a workpiece having a large diameter is cut. Since the structure is formed such that the set width of the tooth group is enlarged which has the tooth tip which substantially describes the imaginary curve or the imaginary straight line near the back surface, the swarf can be fined.
The structure in which both of the back surface and the saw tooth portion are formed into the wavy shapes is considered to attain an oscillation-cutting effect when a
Kamiyama Iwao
Tsujimoto Susumu
Amada Company Limited
Dexter Clark F.
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