JPH04217498A - Drilling tool - Google Patents

Abstract

PURPOSE:To prevent a bore diameter from becoming uneven, in a drilling tool for a rubber plate, etc., by forming a cutting edge in a circular arc shape at the section along one side part of the circumference, and opening the arcuate space inside the blade body toward the other side part of the circumference. CONSTITUTION:A blade body 14 and support part 13 including a cutting edge 15 are formed in a sectional circular arc shape along on the circumference centering around a rotating shaft C, and an arcuate like space 18 surrounded by the internal wall of the blade body 14 is opened toward the other side part of the circumference. This cutting edge 15 is composed of an advancing cutting edge part 19, following cutting edge part 20, and an R-like cutting edge part 21. A shaft part 11 is installed to the chuck of a drill or drilling machine, lowered while rotating a tool, and the cutting edge 15 is advanced to the work of a rubber plate, etc., to execute drilling.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool for making a circular hole in a plate-like body or disk-like body (hereinafter collectively referred to as a plate-like body) such as a rubber plate.

0002

2. Description of the Related Art Conventionally, tools such as those shown in FIGS. 5 and 6 have been used to make circular holes in plate-shaped bodies and the like. This tool is generally referred to as a rotary punch, and includes a shank 1 defining a rotation axis C, a disk portion 2 concentric with the shank 1, and a cylindrical portion extending downward from the outer peripheral edge of the disk portion 2. 3, a cylindrical blade 4 extending further downward from the cylindrical portion 3, and a cutting blade 5 provided at the tip edge of the blade 4. In use, the shank 1 is attached to the chuck of a drill or drilling machine, and the tool is rotated and lowered to allow the cutting blade 5 to enter a workpiece 6 such as a rubber plate.

Since the blade body 4 and the cutting blade 5 enter the workpiece 6 while rotating on the concentric circumference of the rotation axis C, the workpiece 6 is cut into an annular shape corresponding to the shape of the cutting blade 5. A circular hole can be made by passing the blade 4 through the workpiece 6. The punched scraps remaining in the hole are held inside the blade body 4, but by repeatedly performing the drilling work by raising and lowering the tool, a plurality of punched scraps are stacked inside the blade body 4. Therefore, the scraps are gradually pushed up into the cylindrical portion 3 from the top. For this reason, a window hole 7 is formed in the side of the cylindrical portion 3, and after the operator takes out the punched waste from the window hole 7 at a timely manner, the hole-drilling operation is continued.

0004

[Problem to be solved by the invention] Using conventional tools,
When drilling holes in a plate-like material such as an elastic material such as a rubber plate, or a soft material that is easily deformed such as urethane foam or styrofoam, it is not possible to make a perfectly circular hole as expected.

For example, as shown in FIG. 6(B), holes 8 formed in a rubber plate work 6 may have irregular diameters in the thickness direction of the work. The reason for this is that when the tool is lowered and the cutting blade 5 is pressed against the workpiece surface, the elastic plate is compressed and deformed by the pressing force of the cutting blade 5. In particular, the cutting blade 5 is formed into an annular shape. As a result, the rubber material compressed on the inner circumferential side of the cutting blade 5 has no place to escape.
This is because the particles are trapped inside the cutting edge 5. In particular, the amount of compressive deformation of the rubber plate is large at the initial stage of entry of the cutting blade 5, while the amount of compressive deformation of the rubber plate is small at the final stage of entry of the cutting blade 5, so that the elastic material after drilling is In the restored state, the hole diameter is no longer constant in the axial direction.

Furthermore, as shown in FIG. 6(C), when a hole 8 is drilled in a workpiece 6 made of an elastic or soft material, the hole 8 is not perpendicular to the plane of the workpiece 6 and is tilted. There are cases. The reason for this is that the cutting blade 5 is rotated when the annular cutting blade 5 is pressed against the workpiece 6 and enters the workpiece 6.
This is because the cutting edge 5 is not uniformly compressed and deformed over the entire circumference of the cutting edge 5, but is compressed and deformed in a distorted state while being pressed in the rotational direction. In this case as well, the compressively deformed material loses a place to escape due to the annular cutting edge 5, so that the hole 8 becomes tilted and deviated with respect to the restored workpiece 6 after completion of drilling.

[0007] In addition, when drilling holes in elastic or soft materials using conventional tools, it can be seen that holes with various distortions and deviations are made. The problem becomes more pronounced as the wall thickness increases. In order to prevent such compressive deformation of the workpiece, the descending speed of the tool should be extremely low, and the cutting edge 5 should be kept at an extremely low speed.
There is a problem in that the workpiece must be cut gradually, and rapid drilling cannot be expected.

Furthermore, as mentioned above, in conventional tools, the punched scraps generated by drilling are retained inside the cylinder of the blade body 4, and therefore the punched scraps often have to be taken out through the window hole 7. There is a problem in that the work must be interrupted each time. Moreover, if this removal of the punched dregs is neglected, the inner circumferential portion of the cutting blade 5 will become clogged, resulting in a problem in which a hole cannot be drilled.

[0009]

[Means for Solving the Problems] The present invention provides a drilling tool that solves the above-mentioned problems, and the first means thereof consists of a shaft portion defining a rotation axis;
A drilling tool comprising a blade body curved along a circumference centered on the rotation axis, and a cutting blade provided at the tip edge of the blade body, wherein the blade body including the cutting blade is The blade body has an arcuate cross-section along one side of the circumference, and a bay-shaped space surrounded by the inner wall of the blade body is opened toward the other side of the circumference. Further, according to a second means, in addition to the above structure, the cutting blade includes an entry cutting edge portion provided at the tip edge of the blade body along one side of the circumference, and a blade body. and a following cutting edge portion provided on at least one side edge of the open both side edges.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

As shown in FIGS. 1 and 2, the tool includes a shaft portion 11 consisting of a shank defining a rotation axis C;
1, a support portion 13 extending downward from a part of the outer peripheral edge of the disk portion 12, a blade 14 extending further downward from the support portion 13, and at least one of the blades 14. It has a cutting edge 15 provided at the tip edge. In use, as in the past, the shaft portion 11 is attached to the chuck of a drill or drilling machine, and the tool is lowered while rotating.
The cutting blade 15 is inserted into a workpiece 16 such as a rubber plate.

The blade body 14 including the cutting edge 15 and the support portion 13 are curved along a circumference centered on the rotation axis C. At this time, the support portion 13 may be formed in a cylindrical shape, but at least the blade body 14 is not formed in a cylindrical shape as in the conventional example described above, and as shown in FIGS. 2(A) and 2(B). As shown, the cross section is arcuate along one side of a circumference 17 centered on the rotation axis C, and a bay-shaped space 18 surrounded by the inner wall of the blade body 14 is connected to the other side of the circumference 17. It is open towards the side. In addition, as shown in the figure, the support portion 13 is also connected to the blade body 14.
It is preferable to form the cross section into the same arcuate shape.

As shown in FIG. 1, the cutting edge 15 includes an entry cutting edge portion 19 provided at the tip edge of the blade body 14 along one side of the circumference 17, and an entry cutting edge portion 19 provided at the tip edge of the blade body 14, as shown in FIG. a pair of follower cutting blades 20 provided on both side edges of the
. In addition, it is preferable that the following cutting edge parts 20, 20 have an inclination that draws a gentle circular arc toward the approach cutting edge part 19. Incidentally, the reason why the following cutting edge portions 20 are provided on both side edges of the blade body 14 is to enable the tool to be used for both clockwise rotation and counterclockwise rotation. Therefore, if the rotation direction of the tool is limited to one direction,
It is sufficient to provide the following cutting edge portion 20 only on one side edge of the blade body 14 located at least on the front side facing the rotation direction.

The blade body 14 including the cutting edge 15 is shown in FIG.
), it is formed in a substantially semicircular cross section spanning approximately half of the circumference 17 centered on the rotation axis C, that is, approximately 180 degrees around the rotation axis C, and the overall shape is Most preferably, it is approximately semi-cylindrical. However, in an embodiment in which the object of the present invention can be achieved, the cross-sectional shape of the blade body 14 may be an arc of 90 degrees or more and 180 degrees or less, or even if the cross-sectional shape exceeds 180 degrees, the curved space 18 may be Any material that can be opened without substantially clogging is sufficient.

In the illustrated embodiment, the entire cutting edge 15 is a knife-shaped blade, but the entire cutting edge 15, or the approach cutting edge portion 19, the following cutting edge portion 20, which constitute the cutting edge 15,
Saw teeth made of one chevron-shaped blade or a plurality of consecutive chevron-shaped blades may be formed on any part of the rounded cutting edge portion 21.

Further, the flank 22 for forming the sharp edge of the cutting edge 15 can be formed on the outside of the blade body 14 as shown in FIG. 3(A), or on the outside of the blade body as shown in FIG. 3(B). The distortion deformation of the part of the workpiece 16 located inside the rotation locus (circumference 17) of the cutting blade 15, as will be described later, is not limited to the case where the workpiece 16 is formed inside the cutting edge 14. Based on the purpose of preventing this as much as possible, the flank 22 is provided on the outside of the blade body 14 as shown in FIG. It is preferable.

According to the drilling tool based on this embodiment,
When the cutting blade 15 is pressed against the surface of a workpiece 16 such as a rubber plate, the part of the workpiece 16 pressed by the arc-shaped cutting blade 15 is compressively deformed, but other parts are not compressively deformed. do not have. That is, the workpiece 16 to be compressed
Since the portion near the arcuate line is connected to the entire workpiece 16 through the open part of the bay space 18, the arcuate line portion can be compressed without causing large local compressive deformation only in the arcuate line portion. The compressive deformation is distributed throughout the workpiece 16 and relaxed. In other words, unlike the conventional example shown in FIG. 6, the workpiece is not locally compressed and deformed while being enclosed within the annular cutting edge. Since the blade 14 is rotated during the drilling operation, the cutting blade 15 moves along the circumference 17 and repeatedly applies and releases a partial pressing force to the workpiece 16, so it is compressed in a specific part. There is no sustained transformation. Therefore, from when the cutting blade 15 comes into contact with the workpiece 16 until it penetrates the workpiece 16, the portion of the workpiece 16 near the circumference 17 to be cut is
Compared to using the conventional tools mentioned above, the amount of compressive deformation is extremely small, and as a result, it is possible to drill holes with high precision that are extremely close to the desired shape, making it possible to drill holes with irregular diameters unlike conventional tools. This will not cause the hole to deviate in direction.

Further, when drilling a hole, the cutting blade 15 not only has the entry cutting edge part 12 on the leading edge but also the following cutting edge part 2 on both side edges.
0, when the cutting blade 15 enters the workpiece 16 while cutting, it can pass through the annular groove cut by the entering cutting blade part 12 without resistance by the following cutting blade part 20, As a result, the workpiece 16 is not distorted or deformed in the direction of rotation of the cutting blade 15. This resistance can be reduced by giving the trailing cutting edge 20 an inclination angle and by providing the rounded cutting edge 21 from the approach cutting edge 19 to the trailing cutting edge 20, as in the above embodiment. , further improve.

As described above, the tool of the present invention is extremely advantageous when drilling holes in an elastic material such as a rubber plate or a soft material that is easily deformed such as urethane foam or styrene foam. Therefore, a desired perfect circular hole can be made with high precision. In addition to such highly deformable plate-like bodies, the tool of the present invention can also be used when drilling circular holes in plate-like bodies that produce fuzz, so-called hangnails, on the cut surface, such as plywood. This is also advantageous in that the fuzz produced on the cutting surface by the entering cutting edge 12 can be smoothly cut and polished by the following following cutting edge 20, making it possible to drill a circular hole with a good finish.

Further, after drilling is completed, the cutting dregs can be easily removed from the open part of the bay-shaped space 18 by pulling the blade 14 up from the workpiece 16 while rotating it. That is, as described above, the blade body 14 including the cutting edge 15 is formed to have a substantially semicircular cross section over a distance of about 180 degrees or less about the rotation axis C, and the open part of the bay-shaped space 18 is widened. If so, when the cutting blade 15 is pulled up from the workpiece 16, the scraps remain in the hole cut and formed in the workpiece 16 and do not adhere to the cutting blade 15.

On the other hand, when the blade body 14 including the cutting edge 15 is formed over a distance of 180 degrees or more and the open part of the bay-shaped space 18 is formed to be relatively narrow, the punched dregs are formed in the blade body 14 including the cutting edge 15. It is held in the bay-shaped space 18 and pulled out from the workpiece 16 following the cutting blade 15, but the scraps are removed from the bay-shaped space 18.
If the next drilling operation is carried out while the hole is held in place, the punched waste will be pushed upward in the bay-shaped space 18 during the next drilling process, and during this push-up, it will be easily pushed out from the open part of the bay-shaped space 18. . In order to facilitate the extrusion of the removed waste, it is preferable to adopt an additional embodiment as shown in FIG. 4.

That is, in FIG. 4, the blade body 14 has the cutting edge 1
The upper part of the blade 14 and/or the support part 13 is formed in a cross-sectional shape extending over a distance of more than 180 degrees around the rotation axis C in the vicinity of the rotation axis C.
It is formed in a cross-sectional shape spanning a distance of 80 degrees or less. As a result, the bay-shaped space 18 at the lower part of the blade body 14 holds the punched scraps 23, and the width a of the open portion thereof is smaller than the diameter d of the punched scraps 23. On the other hand,
The bay-shaped space 18 in the upper part of the blade body 14 and/or the support part 13 does not enclose the punched scraps 23, and its width b is open to be equal to or exceed the diameter d of the punched scraps 23. Therefore, according to this additional embodiment, the punched scraps 23 are pulled out from the workpiece while being held at the lower part of the blade 14 during drilling, but by repeatedly performing the drilling operation, the punched scraps 23 are pushed upward. When the blade body 14 is closed, the wide open part b of the bay-shaped space 18 at the upper part of the blade body 14
is automatically discharged to the outside.

[0023]

According to the present invention as set forth in claim 1, holes can be formed in a plate-shaped body, especially an elastic material such as a rubber plate, or a soft material that is easily deformed such as urethane foam or polystyrene foam. When using this method, local compressive deformation of the workpiece can be avoided as much as possible, making it possible to drill holes in the desired shape, instead of making holes with irregular diameters or deviating the hole direction as in the past. It does not lead to the opening of a hole in a state of being placed. Moreover, as a result, it becomes possible to increase the descending speed of the tool, which has the effect of shortening the process time of the hole-drilling operation.

According to the second aspect of the present invention, in addition to the above-mentioned effects, it is possible to prevent strain from being applied to the workpiece in the direction of rotation of the blade body including the cutting edge. It becomes possible to make a perfectly circular hole. Moreover, when drilling holes in a plate-like material such as a plywood board, there is an advantage that the cut surface does not become fluffy and the holes can be drilled with an excellent finish.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention.

FIG. 2 shows the state of use of one embodiment of the present invention, in which (A) is a longitudinal cross-sectional view of the entire tool during cutting, and (B) is a cross-sectional view of the blade during cutting.

FIG. 3 shows an embodiment of the cutting blade of the present invention, in which (A) is a vertical cross-sectional view of a so-called inner cutter with a flank provided on the outside, and (B) is a vertical cross-sectional view of a so-called outer cutter with a flank provided on the inside. It is.

FIG. 4 is a perspective view showing an additional embodiment of the invention.

FIG. 5 is a perspective view showing a conventional drilling tool.

FIG. 6 shows the results of using a conventional drilling tool, (A) is a vertical cross-sectional view of the entire tool during cutting, (B) is a vertical cross-sectional view showing an example of a hole drilled in a workpiece, (C ) is a vertical cross-sectional view showing another example of a hole drilled in a workpiece.

[Explanation of symbols]

11 Shaft part 14 Blade body 15 Cutting blade 16 Work 17 Circumference 18 Bay-shaped space 19 Entry cutting edge part 20 Follow-up cutting edge part 21 Rounded cutting edge part 22 Frank

Claims (2)

[Claims] Claim 1: A hole consisting of a shaft defining a rotational axis, a blade body curved along a circumference centered on the rotational axis, and a cutting edge provided at the tip edge of the blade body. In the cutting tool, the blade body including the cutting edge is formed to have an arcuate cross section along one side of the circumference, and a bay-shaped space surrounded by an inner wall of the blade body is formed on the other side of the circumference. A drilling tool characterized by being opened toward the direction of the hole. 2. The cutting edge includes an entry cutting edge provided at the tip edge of the blade body along one side of the circumference, and at least one side edge of the open both sides of the blade body. 2. The drilling tool according to claim 1, further comprising a follow-up cutting edge provided at the bottom of the hole.