JP2002036067A - Holder for cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holder for cutting tool allowing an operation to hold a cutting tool therein and an operation to insert the holder in a packaging container to be performed very safely, surely, and easily, and capable of preventing the blade tip part of the cutting tool from being damaged by the disengagement of the cutting tool from the holder by vibration during the transportation. SOLUTION: In this holder for cutting tool having a plurality of holding parts provided on the laterally elongated substrate thereof, a bottom wall part, a holding part, a connection part, and a holding part are provided on the substrate in that order ranging from one end part thereof, and the thickness of the connection part is formed thinner than that of the substrate to form a bent part. The cutting tool is held on the holding part at the one or two positions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool holder, particularly a small-diameter end mill, a drill, etc., which is fixed in a packaging container when shipped and transported in a packaging container. The present invention relates to a holding tool for holding the object.

[0002]

2. Description of the Related Art When shipping manufactured cutting tools, one or more cutting tools are fixed in a packaging container by a holder in the packaging container before shipment. The fixing is performed so that the cutting edge of the cutting tool does not hit the packaging container or the like due to vibration or the like at the time of transportation and is not damaged. In particular, for a tool having a blade diameter of 3 mm or less, the shank diameter is 3 to 6 mm and the shank length is 3
Because the blade edge is thin and the shank is heavy at 0 to 50 mm,
If the fixing is released, the blade tip is likely to be chipped or broken.

A conventional method for holding a cutting tool in a packaging container will be described with reference to FIGS. The holding method shown in FIG. 13 is performed by inserting the shank 18a of the small-diameter cutting tool 18 into the fine hole 31 formed in the upper surface 30a of the synthetic resin substrate 30 so that the cutting tool 18
Was held and fixed. Then, after inserting the opening of the outer case 32 made of transparent synthetic resin into the step portion 30b of the substrate 30, a label on which the product name, model number, etc. are printed on one side including the boundary between the substrate 30 and the outer case 32 is placed. By sticking, the outer case 32 was prevented from coming off the substrate 30.

FIG. 14 is a sectional view of a conventional example in which the substrate 30 shown in FIG. 13 is improved in order to reduce the size and weight of the packaging container shown in FIG. In FIG. 14, a protrusion 34 that protrudes in a cylindrical shape on the upper surface of the substrate 33 and a plurality of thin ribs 35 are formed inside the protrusion 34 so as to protrude in the central axis direction. Then, the plurality of ribs 35
The shank 1 of the cutting tool 18 in the space formed by the end of
The cutting tool 18 was held and fixed to the substrate 33 by inserting the cutting tool 18a. After the cutting tool 18 is fixed to the substrate 33, a transparent synthetic resin outer case is inserted into the step portion of the substrate 33, including the boundary between the substrate 33 and the outer case, as in the conventional example shown in FIG. The product is shipped with a label on which the product name and model number are printed.

[0005]

In the conventional example shown in FIG. 13, the fine holes 31 formed in the upper surface portion 30a of the substrate 30 allow the shank portion 18a of the cutting tool 18 to be easily inserted, and the vibration at the time of conveyance or the like. It is necessary to accurately process the diameter so that it does not come out easily. Shank part 18a
Although the work of inserting into the fine holes 31 can be automated, when inserting manually, it is necessary to pay attention so that the shank portion 18a is inserted to a specified insertion depth. In particular, when the difference between the diameter of the pore 31 and the diameter of the shank 18a is very small, it is necessary to insert the shank 18a into the pore 2 with sufficient force. For this reason, there is also a risk of inadvertently touching the blade edge portion 18b with the hand and causing injury.
Further, when the difference between the diameter of the fine hole portion 31 and the diameter of the shank portion 18a is large, the shank portion 18
There was also a risk that a would fall out of the pores 31. Further, even when the cutting tool 18 is pulled out from the fine hole 31 by a tool user or the like, there is a risk that the cutting edge 18b may be inadvertently touched with the hand and injured. Further, in order to process the pores 31 in the substrate 30 made of a solid synthetic resin, the dimensions of the substrate 1 must be increased, and the processing accuracy of the diameter needs to be increased. There was a drawback of becoming high.

The conventional example shown in FIG. 14 has an effect of cost reduction by downsizing and weight reduction. However, similar to the conventional example shown in FIG. 13, when inserting and removing the shank portion 18a from the substrate 33, the conventional example shown in FIG. It was necessary to insert and remove the shank of the cutting tool in the axial direction of the hole formed in the substrate. For this reason, there is a high risk that a fingertip or the like touches the cutting edge of the cutting tool, and there is also a safety problem.

[0007] An object of the present invention is to solve the above-mentioned conventional drawbacks, and to provide an extremely safe operation when holding a cutting tool in a holder and inserting the holder into a packaging container.
An object of the present invention is to provide a cutting tool holder that can reliably and easily work, and does not cause the cutting edge of the cutting tool to be detached from the holder due to vibration during transportation, thereby causing damage to the cutting edge of the cutting tool.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a cutting tool holder in which a plurality of holding portions are provided on a horizontally long substrate, wherein a bottom wall portion, a holding portion, a connecting portion, and a holding portion are provided from one end of the substrate. A connecting portion, the connecting portion having a thickness smaller than the thickness of the substrate to form a bent portion, and one or two portions of the holding portion.
A cutting tool holder characterized in that the cutting tool is sandwiched and gripped at all locations. Further, the sum of the length of the holding portion, the connecting portion, the holding portion is longer than the shank length of the cutting tool to be held, and the connecting portion has a V shape, an arc shape, a step portion, and the like. A bent portion is provided by reducing the thickness of the substrate.
The width of the opening formed in the holding portion is provided smaller than the shank diameter of the cutting tool, and the entire structure including the holding tool, the holding portion, the connecting portion, and the bottom wall portion is integrally formed of synthetic resin or the like. Cutting tool holder. Less than,
An embodiment of the present invention will be described with reference to the drawings.

[0009]

FIG. 1 is a perspective view showing a first embodiment of the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a top view thereof. As shown in FIGS. 1 to 3, a cutting tool holder 1 of the present invention includes a plurality of holding portions 3, 5, a connecting portion 4 between holding portions, and a bottom wall portion 6 on a horizontally long thin plate-shaped substrate 2. Consists of

First, as shown in FIG. 3, the holding portion 3 (hereinafter, referred to as a first holding portion) is composed of a pair of expandable rising walls 7 and 8 and a shank support portion 9. I have. The pair of rising walls 7 and 8 are erected from both sides in the longitudinal direction of the substrate 2 so as to face each other. And
As shown in the cross-sectional view taken along the line BB in FIG. 4B, the inner walls of the rising walls 7 and 8 facing each other, and the cross-section is lowered in the direction of the inverted C in the direction of the substrate 2 from near the upper end thereof. The slant surface 7a,
8a, a shank grip 10 having an arc-shaped cross section is formed below the inclined surfaces 7a, 8a. The shank grip 10 is formed to have a predetermined length in the longitudinal direction of the substrate 2. Further, an opening is formed such that the width dimension between points where the shank gripping portion 10 having an arc-shaped cross section intersects the inclined surface portions 7a and 8a is a1. This width a1 is formed to be smaller than the shank diameter of the tool. That is, the central angle S of the arc of the shank grip 10
1 is preferably set to about 200 ° to 270 °.

Second, the shank support 9 shown in FIG.
Is provided continuously or near the rising walls 7 and 8,
At the center of the upper surface, a support surface 11 having an arc-shaped cross section is provided.
To form The arc-shaped support surface 11 is formed to have a predetermined length in the longitudinal direction of the substrate 2. The central angle of the arc-shaped support surface 11 is a semicircular shape of about 180 degrees or a central angle of 180 degrees or less, and the diameter is substantially the same as the diameter of the shank diameter to be held. I do.

Third, the structure of the holding portion 5 (hereinafter, referred to as a second holding portion) is substantially the same as the structure of the first holding portion 3 described above, and as shown in FIG. It is composed of a pair of rising walls 12 and 13 that can be opened and a shank support 14. The inner surfaces of the rising walls 12 and 13 are provided with inclined surfaces 12a and 13a whose cross-sectional shape descends in the direction of the substrate 2 in the direction of the substrate 2 from the vicinity of the upper end thereof, and below the inclined surfaces 12a and 13a. The shank grip 15 has a circular cross section. This shank gripper 1
5 is formed to have a predetermined length in the longitudinal direction of the substrate 2. Further, the shank gripping portion 15 having an arc-shaped cross section
Has a width b1 between the points where it intersects the inclined surfaces 12a and 13a.
An opening K2 is formed. The width b1 of the opening K2 is formed so as to be smaller than the diameter b0 of the shank grip 10, and the diameter b0 is formed so as to be substantially the same as the diameter of the shank of the cutting tool to be held. Further, it is preferable that a1 = b1 or a1> b1. That is, as shown in FIG. 5B, the central angle S2 of the arc of the shank grip 15 may be set to be about 200 ° to 360 °.

[0013] The shank support portion 14 includes the rising wall 12,
A support surface 16 having an arc-shaped cross section is formed at the center of the upper surface of the first holding portion 3 in the direction of the first holding portion 3 continuously or in the vicinity of the support portion 13. The arc-shaped support surface 16 is
Is formed so as to have a predetermined length in the longitudinal direction. Also, the center angle of the arc-shaped support surface 16 is set to a semicircular shape of about 180 degrees or an angle of 180 or less, and the diameter is made substantially the same as the diameter of the shank portion to be held. The height of the rising walls 12 and 13 is set to be equal to the height of the rising walls 7 and 8.
It is almost the same as the height.

Fourth, in the present invention, the shank grip 10, the support surface 11, the shank grip 15, the support surface 16
And heights T1, T2, T3, T4 from the extension surface of the substrate 2
Are formed so as to be substantially the same, and the arc-shaped shank grip portion 10, the support surface 11, and the shank grip portion 1
5. The line connecting the centers of the arcs of the support surface 16 is substantially collinear and substantially parallel to the longitudinal direction of the substrate 2.

Fifth, a bottom wall 6 is provided upright at an end of the second holding portion 5 in a direction orthogonal to the longitudinal direction of the substrate 2. The height of the bottom wall portion 6 is substantially the same as or slightly lower than the heights of the rising walls 7, 8 and the rising walls 12, 13, so that when the cutting tool is held on the holder 1, the shank thereof is Ensure that the entire surface of the end of the part has a height that can be securely contacted.

Sixth, the first holding unit 3 and the second holding unit 5
2, has a predetermined length n2 in the longitudinal direction of the substrate 2, and has a thickness t0.
Is smaller than the thickness t1 of the substrate 2,
However, a bent portion that is easily bent in a direction perpendicular to the longitudinal direction of the substrate 2 is formed. Note that the thickness t0 of the connecting portion is preferably set to 10 to 80% of the thickness t1 of the substrate 2.

Seventh, near the other end 2b of the substrate 2,
A grip 17 is formed. This grip 17 is circular,
It can be punched into squares, rectangles, polygons,
Alternatively, minute uneven portions are formed. The material of the cutting tool holder 1 of the present invention described above is made of a synthetic resin having elasticity, preferably polypropylene, using an injection molding machine, and the substrate 2, the first holding portion 3, and the connecting portion. 4, all the components such as the second holding portion 5, the bottom wall portion 6 and the like can be integrally formed.

Eighth, the dimensional relationship of each part of the cutting tool holder 1 described above may be set as follows. That is,
n1 = (length of shank support 9 + shank gripper 10
Length), n2 = length of connecting portion 4 in the longitudinal direction of substrate 2,
n3 = (length of shank support portion 14 + shank holding portion 1)
5 length + thickness of bottom wall 6), n0 = n1 + n2 + n3
Then, it is preferable that n0 ≦ the shank length of the cutting tool to be held (1) n2 + n3 = (0.5 to 0.8) n0 (2)

The reasons for limiting the dimensions as described above are as follows. That is, it is necessary to satisfy the above-mentioned expression (1) in order to firmly hold the two positions of the shank portion 18a. When a cutting tool having a shank length of about 30 to 50 mm is held, the shank portion 18a is inserted into the holding portions 3 and 5 by a manual operation described later, but if the above expression (2) is satisfied, the fingertip of the left hand is used. Of the holding portion 5 can be easily held.

Ninth, FIG. 6 shows a state in which a cutting tool is set.
This will be described with reference to FIG. 6 is a side view when the cutting tool 18 is held by the holder 1, FIG. 7 is a top view of FIG.
8 (a), 8 (b), 9 (a) and 9 (b) are EE, FF, GG and HH sectional views of FIG. 7, respectively.

As shown in FIGS. 6 and 7, the cutting tool 18 having the shank portion 18a and the blade portion 18b is in a state where the end portion 18c of the shank portion 18a is in contact with the bottom wall portion 6.
The shank portion 18a is inserted into the shank grip portion 10 of the first holding portion 3 and the shank grip portion 15 of the second holding portion 5, and is pinched and held by the shank grip portions 10, 15. Further, the shank portion 18a is
And the arc-shaped support surface 16 of the shank support portion 14. Therefore, the blade portion 18b of the cutting tool 18 is at a predetermined height h from the substrate 2 and is in an unsupported state. As described above, in the cutting tool holder 1 of the present invention, the cutting tool 18 is parallel to the longitudinal direction of the substrate 2, and the shank portion 18 a thereof is placed at the two positions of the first holding portion 3 and the second holding portion 5. The blade portion 18b can be firmly held on the substrate 2 in an unsupported state at a predetermined height from the substrate 2.

Tenth, a procedure for holding the cutting tool 18 in the cutting tool holder 1 will be described. Although this procedure can be automated using a handling robot, a procedure for manually holding the procedure will be described below.

1) First, in the state where the cutting tool holder 1 is placed on the work table, the vicinity of the second holding portion 5 is grasped with the fingertip of the left hand, and the shank of the cutting tool 18 grasped by the fingertip of the right hand. With the end 18c of the portion 18a aligned with the bottom surface of the bottom wall 6, the shank portion 18a is placed on the openings K1 and K2. Since the width a1 of the opening K1 and the width b1 of the opening K2 are formed to be smaller than the diameter of the shank 18a, the shank 18a can be placed on the opening K1 and the opening K2. .

2) Subsequently, the shank portion 18 is formed with the fingertip of the right hand.
a is pressed in the direction of the substrate 2. Then the rising wall 7
4a, 8a and the rising walls 12a, 13a are made of an expandable elastic material (polypropylene or the like).
(A), widths a1 of openings K1 and K2 shown in FIG.
b1 expands outward, and the shank portion 18a is inserted into the shank grip portion 10 and the shank grip portion 15. When the shank portion 18a is inserted into the shank grip portions 10, 15, the widths of the openings K1 and K2 return to the original widths a1 and b1. In this manner, the cutting tool 18 can firmly hold the blade portion 18b in the longitudinal direction of the substrate 2 at a predetermined distance h from the upper surface of the substrate 2. Even when the center angle S2 of the shank grip 15 is close to 360 degrees, that is, even when the width b1 of the opening K2 is 0, the strength and elasticity of the cutting tool holder including the rising walls 12 and 13 are appropriate. If a synthetic resin having a certain thickness is selected, the width b1 can be expanded outward by the above-mentioned pressing force, and the shank portion 18a can be inserted into the shank grip portion 15. Further, in the present invention, by supporting the shank portion 18a of the cutting tool by the shank support portions 9 and 14, an effect that the cutting tool 18 can be securely held along the longitudinal center line of the substrate 2 is produced.

In the procedure 1) for holding the cutting tool 18 on the holder 1, the end 18c of the shank 18a of the cutting tool 18 is connected to the shank grip 15 formed by the second holding section 5 and the shank. The shank 18b may be inserted obliquely from the interface with the support 16 in the direction of the bottom wall 6 so that the shank 18b is placed on the opening K1.

Eleventh, a procedure for inserting the cutting tool 18 held by the cutting tool holder 1 into the packaging container will be described with reference to FIG. The packaging container includes an inner case 19 and an outer case 20. Horizontally rectangular parallelepiped inner case 19
Has a bottom 19a at one end and an opening 19 at the other end.
b and the length in the lateral direction is shorter than the length of the cutting tool holder 1. An outer case 20 also having a horizontally long rectangular parallelepiped shape
Has a bottom 20a at one end and an opening 20b at the other end. The cutting tool holder 1 can be inserted into the inner case 19, and the inserted cutting tool holder 1 does not rattle in the inner case 19, and the outer surface of the inner case 19 , The cross-sectional dimension thereof is appropriately formed so that the outer case 20 can be inserted. The inner case 19 and the outer case 20 are preferably made of a transparent or translucent synthetic resin so that a cutting tool inserted from the outside can be checked.

First, as shown in FIG. 10A, the cutting tool holder 1 holding the cutting tool 18 is inserted into the inner case 19 from the opening 19b of the inner case 19. At this time, the cutting tool holder 1 is inserted into the inner case 19 from the bottom wall 6 so that the bottom wall 6 contacts the bottom 19 a of the inner case 19. In this state, the length of the inner case is appropriately formed such that the vicinity of the grip portion 17 formed at the end 2a of the cutting tool holder 1 is exposed at least 15 mm or more from the opening 19b of the inner case 19. deep. Subsequently, the opening 20b of the outer case 20 is inserted from the outer surface of the opening 19b of the inner case 1. In this insertion, as shown in FIG. 10B, the outer case 20 is sufficiently inserted into the outer surface of the inner case 19 until the bottom 20a of the outer case 20 comes into contact with the end 2a of the holder 1 for a cutting tool. . This can prevent the cutting tool holder 1 from rattling in the longitudinal direction in the packaging container. When this insertion operation is completed, the outer case 20
A sticker on which the product name of the cutting tool 18 is printed is attached to the side surface of the packaging container including the opening 20b to prevent the outer case 20 from coming off the inner case 19.

Next, a procedure of taking out the cutting tool 18 inserted into the packaging container by a user of the tool or the like will be described. 1) First, the seal attached to the side surface of the packaging container is peeled off, and the outer case 20 is removed from the inner case 19. Then
Since the grip 17 formed at the end 2a of the cutting tool holder 1 is exposed from the opening 19a of the inner case 19, the grip 17 is gripped by a fingertip, and the cutting tool holder 1 is removed. Take it out of the inner case 19. At this time, since the grip portion 17 is formed with a circular, square, rectangular, or polygonal punch, or has a small uneven portion, even if oil or the like adheres to the fingertip, the grip portion 17 is securely held with the fingertip. Can be grasped. Further, as described above, when the end portion 2a including the grip portion 17 of the cutting tool holder 1 is exposed from the inner case 19 by 15 mm or more, the grip of the grip portion 17 becomes easy with a fingertip.

2) Subsequently, in the state where the vicinity of the second holding portion 5 formed on the holder 1 for the cutting tool is gripped by the fingertip of the left hand, the vicinity of the end 2a of the holder 1 for the cutting tool is used for the fingertip of the right hand. And lightly push down in the direction of arrow Y as shown in FIG. Then, as shown in FIG. 2, since the thickness t0 of the connecting portion 4 is smaller than the thickness t1 of the substrate 2, the connecting portion 4 is moved in the longitudinal direction of the substrate 2 by a slight force by the leverage principle. Simultaneously, the shank 18a is disengaged from the shank grip 10 of the first holding portion 3 as shown in FIG. If the total length L of the cutting tool holder 1 is set to be longer than the total length of the cutting tool 18 by 20 mm or more, the vicinity of the end 2a is gripped by the fingertip of the right hand, and when the blade is lightly pushed down in the arrow Y direction, the cutting edge The portion 18b can be prevented from contacting the fingertip.

3) In the state shown in FIG. 11, the shank portion of the cutting tool 18 is grasped with the fingertip of the right hand, and the cutting tool 18 can be easily removed from the holder 1 for the cutting tool. Further, since the cutting tool holder 1 from which the cutting tool 18 has been removed is formed of a synthetic resin made of an elastic material such as polypropylene, the connecting portion 4 is bent from the state shown in FIG. It returns to a flat state as shown in FIG. Thus, the operation of holding the used cutting tool 18 again in the cutting tool holder 1 and storing it in the tool storage tool or the like can be performed without any trouble.

As described above, in the present invention, even when the cutting tool 18 held by the cutting tool holder 1 is removed, it is ensured that the cutting edge 18b of the cutting tool 18 contacts the hand or the fingertip. Can be prevented.

In the embodiment of the present invention described above, the shape of the connecting portion 4 may be V-shaped as shown in FIG. 12A, arcuate as shown in FIG. By providing the step portion as shown in FIG. 3C, the thickness of the connecting portion 4 can be made smaller than the thickness t0 of the substrate 2 to form a bent portion that can be easily bent.

In the present invention, the shank grip 1
The shank support portions 9 and 14 formed continuously or in the vicinity of the end portions 0 and 15 may be formed at the left and right ends of the shank grip portions 10 and 15 or at one end thereof. further,
The shank supports 9, 14 may be omitted.

[0034]

The cutting tool holder of the present invention described above has the following effects. 1) Since the injection molding machine can be formed into an integrated structure into a miniaturized shape and the packaging container for storing the cutting tool holder can be miniaturized, the manufacturing cost is lower than that of the conventional cutting tool holder. Can be reduced to 1/4 or less. 2) Since the two locations of the shank portion of the cutting tool are firmly held, it is possible to prevent the cutting tool from coming out of the cutting tool holder due to vibrations during transportation at the time of shipping. This allows
It is possible to eliminate the risk of damaging the blade. 3) When the cutting tool is held by the holder for the cutting tool and when the cutting tool is removed, it is possible to prevent the blade portion of the cutting tool from touching a hand, a finger, or the like and being injured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a holder for a cutting tool of the present invention.

FIG. 2 is a side view of the cutting tool holder shown in FIG. 1;

FIG. 3 is a top view of the cutting tool holder shown in FIG. 1;

FIG. 4A is a sectional view taken along line AA of FIG. 3, FIG.
(B) shows the BB sectional view of FIG.

FIG. 5A is a cross-sectional view taken along line CC of FIG. 3;
(B) shows the DD sectional view of FIG.

6 is a side view showing a state in which the cutting tool is held and held by the holder for the cutting tool shown in FIG. 1;

FIG. 7 is a top view showing a state when the cutting tool is sandwiched and held by the cutting tool holder shown in FIG. 1;

8A is a sectional view taken along line EE of FIG. 7, FIG.
(B) shows an FF sectional view of FIG. 7.

9A is a sectional view taken along line GG of FIG. 7, FIG.
(B) shows an HH sectional view of FIG. 7.

10A and 10B are diagrams showing a procedure for storing the cutting tool holder shown in FIG. 6 in a packaging container, and FIG. 10A is an explanatory view showing a state where the cutting tool holder is inserted into an inner case; FIG. 4 is an explanatory view showing a state where an outer case is inserted into an inner case.

FIG. 11 is an explanatory diagram for explaining a procedure for removing a cutting tool held by the cutting tool holder shown in FIG. 6;

12 is an enlarged sectional view of a main part showing another embodiment of the connecting portion of the holder for the cutting tool shown in FIG. 2;

FIG. 13 is an explanatory view showing an example of a conventional cutting tool holder.

FIG. 14 is a cross-sectional view showing an example of a conventional holder for a cutting tool.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holder 2 Substrate 2a End part 3 1st holding part 4 Connecting part 5 2nd holding part 6 Bottom wall part 7 Rise wall 7a Slant surface part 8 Rise wall 8a Slant surface part 9 Shank support part 10 Shank grip part 11 Support surface 12 rising wall 12a inclined surface 13 rising wall 13a inclined surface 14 shank support 15 shank grip 16 support surface 17 grip 18 cutting tool 18a shank 18b blade tip 19 inner case 19a bottom 19b opening 20 outer case 20a bottom 20 Part K1 Opening K2 Opening

Claims (5)

[Claims] A cutting tool holder comprising a horizontally long substrate provided with a plurality of holding portions, wherein one end of the substrate has a bottom wall portion,
A holding portion, a connecting portion, and a holding portion, wherein the thickness of the connecting portion is provided to be smaller than the thickness of the substrate to form a bent portion, and the cutting tool is gripped at one or two positions of the holding portion. A holder for a cutting tool, characterized in that: 2. The cutting tool holder according to claim 1, wherein a sum of lengths of the holding portion, the connecting portion, and the holding portion is longer than a shank length of the cutting tool to be held. Holder. 3. The holder for a cutting tool according to claim 1, wherein the connecting portion has a V-shape, an arc shape, a step portion, or the like, thereby reducing the thickness of the substrate. Cutting tool holder. 4. The holding tool for a cutting tool according to claim 1, wherein in the holding, the width of an opening formed in the second holding portion is smaller than a shank diameter of the cutting tool. Characteristic cutting tool holder. 5. The cutting tool holder according to claim 1, wherein the entire structure including the holder, the holding portion, the connecting portion, and the bottom wall portion is integrally formed of synthetic resin or the like. Holder for cutting tools.