JPH0219212Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to bits for routers.

In conventional router bits, as shown in Fig. 1 A and B, a pair of chips c and c are connected to each other so that the cutting edges k of both chips c and the contact point t of k coincide with the rotational axis of both cutting edges k. Because it is attached to the tip of the bit B, it has the disadvantage that the strength near the tip decreases, and the rake surface shrinks near the contact point t, which obstructs the discharge of chips near the contact point t. There was a drawback that the area near t was easily burnt out during cutting.

The purpose of the present invention is to provide a router bit which eliminates the above-mentioned drawbacks, and in which both rake surfaces of a pair of tips attached to the blade part in a substantially rotationally symmetrical manner are aligned with the rotation axis of the blade part. and the contact point between the main cutting edge formed at the leading edge of the rake face of one of the chips and the auxiliary cutting edge formed at the leading edge of the rake face of the other chip. A bit for a router in which the side surface near the tip of the main cutting edge is formed in a mountain shape with the intersection of the main cutting edge and the rotation axis as the apex by deviating the rotation axis toward the sub-cutting edge side. The main points are as follows.

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawing, 1 indicates a pair of conical flanks 1a, 1a at the tip of the router bit B.
and a blade portion formed such that a pair of grooves 1b, 1b are arranged in a row alternately, 2A, 2B are both grooves 1b.
A pair of tips are attached so as to be opposed to each other in a substantially rotationally symmetrical manner with respect to the planar end surfaces 1c and 1c, and both rake faces 7 of both tips 2A and 2B are aligned with the rotation axis J of the blade portion 1. A main cutting edge 3a formed at the tip edge of one chip 2A and a minor cutting edge 3b formed at the tip edge of the other chip 2A are arranged in the same plane passing through the main and minor cutting edges. 3a,
The contact points 8 of 3b are connected linearly in front within a plane passing through the rotation axis J in a state of being deviated from the rotation axis J toward the sub-cutting edge 3b side. The side shape near the tip of the main cutting edge 3a is the main cutting edge 3a and the rotation axis J.
It is formed in a mountain shape with the intersection point 5 as the apex of the tip, and a folded part 6 extending from the intersection point 5 toward the sub-cutting edge 3b side is formed at the tip of the main cutting edge 3a, and one tip 2A Near the tip of the rake face 7, there is a mountain-shaped corner face 7a with the folded part 6 as one side and the intersection 5 as the apex.
It is formed to expand the effective area near the tip.

Next, the operation and effects of the embodiment having the above configuration will be explained.

In this example, both rake faces 7 of a pair of tips 2A and 2B attached to the blade part 1 in a substantially rotationally symmetrical manner are arranged in the same plane passing through the rotation axis J of the blade part 1, and one tip The main cutting edge 3a formed at the tip edge of the rake face 7 of 2A and the other tip 2B
A sub-cutting edge 3b formed on the tip edge of the rake face 7
The contact point 8 with the main cutting edge 3a is deviated from the rotational axis J toward the sub-cutting edge 3b side, so that the side surface shape near the tip of the main cutting edge 3a is shaped like a mountain with the intersection point 5 between the main cutting edge 3a and the rotational axis J as the apex. It is formed in

Therefore, the rake face 7 of the tip 2A on one side is expanded at the folded part 6, and the problem of burnout near the tip of the cutting edge 3 during cutting is suppressed, and the discharge passage for chips cut at the corner part 7a is prevented. This makes it easy to discharge chips, and the strength near the tip of the cutting edge 3 can be increased by the folded portion 6 to maintain cutting performance.

Furthermore, since the main and sub-cutting edges 3a and 3b are connected in a symmetrical mountain shape, the rotational balance during cutting of the bit B is maintained, and unevenness in cutting resistance can be eliminated.

Further, since the side surface near the tip of the main cutting edge 3a is shaped like a mountain and a corner portion 7a shaped like a mountain is formed near the tip of the chip 2A, the cross section becomes V.
It is possible to precisely cut a shaped groove, and also to reduce the cutting resistance when cutting this groove.

Since the router bit of the present invention has a blade apex with a pointed apex formed by one of the tips, it is possible to prevent burnout at the contact point of both tips and increase the effect of discharging cutting waste, and also to This has the effect of reducing cutting resistance and allowing V-shaped grooves to be cut accurately and easily.

[Brief explanation of the drawing]

Figures 1A and 1B show a front and side view of a conventional router bit, and Figures 2 to 4 show an embodiment of the present invention. Figure 2 is a front view, and Figure 3 is a side view. A right side view, and FIG. 4 is a left side view. 2A, 2B...chip, 3...cutting edge, 3a...
...Main cutting edge, 3b...Sub-cutting edge, 5...Point, 6
...Folded part, 8...Contact, J...Rotation axis center, B
...Bits.

Claims (1)

[Scope of utility model registration request] Both rake surfaces of a pair of tips attached to the blade portion in a substantially rotationally symmetrical manner are arranged in the same plane passing through the rotational axis of the blade portion, and a tip is formed on the tip edge of the rake surface of one of the tips. The main cutting edge is
The contact point with the auxiliary cutting edge formed on the tip edge of the rake face of the other tip is shifted from the axis of rotation toward the auxiliary cutting edge side, and the side surface shape near the tip of the main cutting edge is changed to the main cutting edge. A bit for a router, characterized in that the bit is formed into a mountain shape with the apex at the intersection of the cutting edge and the rotation axis.