JP2003103072A - Shearing blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a shearing blade to cut the hair precisely and appropriately. SOLUTION: The shearing blade comprises a stationary blade 12 formed by aligning many comb-shaped blades 15 in the horizontal direction and a movable blade 13 formed by aligning many comb-shaped blades 20 in the horizontal direction. Reciprocal sliding motions in the horizontal direction by the movable blade 13 against the stationary blade 12 cut the hair 9. A dented part 17 to avoid sliding contact with the other part is formed on a sliding surface of at least either the stationary blade 12 or the movable blade 13 formed by etching respectively, and through-holes 45 are made on the dented part 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shear blade in which a fixed blade and a movable blade are in sliding contact with each other in surface contact. The fixed blade and the movable blade are formed by an etching method, and are applied to eyebrow cutters, electric razor's razor blades, downy hair cutters, clipper blades, and the like.

[0002]

2. Description of the Related Art For example, it is known to form a shearing blade by an etching method in a razor blade of an electric razor (Japanese Patent Publication No. 36-19556). Japanese Patent Laid-Open No. 1-25
Japanese Patent No. 9891 describes that a fixed blade and a movable blade are each formed by a photoetching method.

[0003]

The blade formed by the etching method can have a smaller thickness dimension as compared with the blade formed by press working, and high surface accuracy can be obtained because no distortion remains during processing. . Therefore, the blade surfaces of the fixed blade and the movable blade can be brought into close contact with each other to improve the sharpness during shearing. The problem is that when both the fixed blade and the movable blade are formed into a flat plate shape by the etching method, the contact area between the two becomes large and the frictional resistance increases accordingly. In order to avoid such a situation, the applicant has previously proposed to form a concave portion on the sliding surface side of the fixed blade or the movable blade by an etching method.

A plate-shaped steel material, which is an etching material, is preliminarily quenched to ensure hardness. Bending stress acts on the steel material after quenching. there,
When the concave portion is formed by the etching method, the entire fixed blade including a large number of comb-shaped blade portions is curved (see FIG. 16), the sliding contact with the comb-shaped blade portion of the movable blade becomes local, and Shearing cannot be done efficiently. In addition, the heat generated by the local sliding contact may cause the user to feel uncomfortable.

An object of the present invention is to obtain a shearing blade which can surely and appropriately cut the bristles so that the comb-shaped blade portions formed on the fixed blade and the movable blade can be evenly adhered to each other.

[0006]

A shear blade targeted by the present invention comprises a fixed blade 12 having a large number of comb-shaped blades 15 arranged in the left-right direction and a large number of comb-shaped blades 20 arranged in the left-right direction. It has a movable blade 13 that slides back and forth in the left-right direction with respect to the fixed blade 12. The shear blade here is the shear blade of the hair clipper, the razor blade of the electric razor, the downy hair cutter,
The eyebrows cutter etc. correspond.

The present invention is directed to such a shear blade as shown in FIG.
As shown in (a) and (b), the sliding surface 12 of the fixed blade 12 and the movable blade 13 formed by the etching method, respectively.
A recess 17 is formed in at least one of a and 13a to avoid sliding contact with a sliding partner, and the recess 1
A through hole 45 is formed in 7.

More specifically, the through holes 45 are arranged in a row in the left-right direction.

Further, a through hole 12c for inserting the projection 18 is arranged in a recess 17 formed on the sliding surface 12a side of the fixed blade 12, and a guide groove 22a extending in the left-right direction is provided on the movable blade 13. The guide body 22 is fixed, and the projection 18 is fitted into the guide groove 22a, whereby the movable blade 13 is guided so as to reciprocate only in the left-right direction with respect to the fixed blade 12.

The through holes 45 are arranged in rows in the left-right direction with reference to the through holes 12c through which the protrusions 18 are inserted.

The movable blade 13 is curved or bent toward the fixed blade 12 side.

[0012]

In the shear blade according to the present invention, at least one of the sliding surfaces 12a and 13a of the fixed blade 12 and the movable blade 13 formed by the etching method is brought into sliding contact with a sliding partner. By forming the recesses 17 to be avoided and forming the through holes 45 in the recesses 17, it is possible to reduce the bending stress that tends to bend around the axis along the axis line in the direction orthogonal to the left-right direction. The fixed blade 12 and the movable blade 13 can be slidably contacted in the state of evenly adhering in the left-right direction. As a result, since the comb-shaped blades 15 and 20 formed on the fixed blade 12 and the movable blade 13 can evenly contact and slide, it is possible to surely and properly cut the hair, which is an object to be cut.

Further, since the through holes 45 are arranged in a row in the left-right direction, it is possible to efficiently and uniformly prevent bending stress from being applied to the comb-shaped blades 15 and 20 arranged in the left-right direction. .

Further, a through hole 12c through which the projection 18 is inserted is arranged in a recess 17 formed on the sliding surface 12a side of the fixed blade 12, and the movable blade 13 has a guide groove 22a extending in the left-right direction. Since the guide body 22 is fixed and the projection 18 is fitted into the guide groove 22a, the movable blade 13 is guided so as to reciprocate only in the left-right direction with respect to the fixed blade 12. Even if it projects from the movable blade 13 side to the fixed blade 12 side, this is the concave portion 17 of the fixed blade 12.
Since the guide body 22 and the fixed blade 12 are prevented from coming into contact with each other by entering the inside, wear and the like due to these contact can be well prevented. Further, the protrusion 18 is fitted into the guide groove 22a, so that the reciprocating motion of the movable blade 13 in the left-right direction is guided, and the movable blade 13 can accurately reciprocate, thereby improving the sharpness of the shear blade. be able to. Moreover, when the concave portion 17 is formed on the sliding surface 12a side of the fixed blade 12, the contact area between the fixed blade 12 and the movable blade 13 is reduced, so that the fixed blade 12 and the movable blade 13 are pressed into contact with each other. Even if the biasing force of the spring is reduced, a contact pressure that is the same as when the spring pressure for full-surface contact is set can be obtained, so that frictional resistance can be reduced and power consumption can be reduced. Further, the through hole 12c can also function as the through hole 45 for preventing bending stress, which is advantageous in terms of ensuring strength.

Further, by arranging the through holes 45 in a row in the left-right direction based on the through holes 12c through which the protrusions 18 are inserted, the straight through holes 45 including the through holes 12c are formed. It is possible to efficiently and uniformly prevent bending stress with respect to the comb-shaped blades 15 arranged in the direction.

Further, since the movable blade 13 is curved or bent toward the fixed blade 12 side, the strength of the movable blade 13 can be improved and a gap may be formed between the comb-shaped blades 15 and 20. Since it is not present, it is possible to surely and properly cut the hair, which is the object to be cut. Moreover, even if bending stress that tends to bend around an axis along the axis orthogonal to the left-right direction occurs, it can be prevented as much as possible, so The contact can be made uniformly. As a result, uneven wear and defective cutting can be reliably prevented.

[0017]

The drawings show an embodiment of a shear blade according to the present invention. In FIG. 2, a motor 3, a battery 4 and the like are arranged inside a cylindrical body case 1. A shear blade 5, which is a target of the present invention, is arranged on the head portion 2 of the main body case 1. On the front surface of the body case 1, as shown in FIG. 3, there is a starting switch 6 for turning on and off the power supply to the motor 3.

A drive mechanism for converting the rotational driving force of the motor 3 into a reciprocating motion in the left-right direction and transmitting it to the shear blade 5 is provided in the main body case 1. This drive mechanism uses the motor 3
Of the eccentric cam 7 connected to the output shaft of the eccentric cam, the vibrator 8 connected to the shear blade 5, and the like. The vibrator 8 is moved in the left-right direction by the crank pin 7a protruding from the eccentric position of the eccentric cam 7. Reciprocates.

The shearing blade 5 is fixed to the head portion 2 of the main body case 1 via a holder 16 made of synthetic resin or the like, and a movable blade fixing base 21 inside the upper surface of the holder 16 for the shearing blade 5. The movable blade 13 is reciprocally driven by the vibrator 8 in the left-right direction. The movable blade 13 is constantly pressed and biased toward the fixed blade 12 by a pair of left and right torsion coil springs 14. The movable blade fixing base 21 is made of synthetic resin or the like, and is a passive portion 21a that receives the reciprocating motion of the vibrator 8.
Is provided. The holder 16, the fixed blade 12, the torsion coil springs 14, 14, the movable blade fixing base 21 and the movable blade 13 are integrally assembled into a unit, and the unitized shear blade 5 is attached to the head portion 2. Can be detachably attached.

The fixed blade 12 and the movable blade 13 are formed by an etching method using a hardened steel plate material, more preferably a hardened martensitic stainless steel plate material. That is, for example, a film-shaped photosensitive film is baked and developed on the upper and lower surfaces of the above plate material through a photomask, and as shown in FIGS. 7 and 8, a photoetching method using a patterned corrosion-resistant resist film 25 is used. Formed by. As the etching solution in this case, for example, ferric chloride is used. As for the patterned resist film 25, various methods of forming the resist film 25, such as a method of directly irradiating a photosensitive film with a laser beam to cure and form it without using a photomask, can be considered.

The total thickness of the fixed blade 12 is, for example, 0.8.
As shown in FIG. 4, the holder 16 is made of a mm plate, and the four caulking protrusions 16a protruding from the holder 16 are respectively passed through the four through holes 12d provided in the fixed blade 12 to caulk the holder. It is fixed at 16.

In FIGS. 1 (a) (b) to 4, a plurality of comb-shaped blades 15 whose width is gradually narrowed toward the tip side are arranged at the front end of the fixed blade 12 in the left-right direction. The torsion coil spring 14 is attached to a holder 16 to which the fixed blade 12 is fixed. Fixed blade 12
In order to reduce the friction between the movable blade 13 and the movable blade 13, a concave portion 17 is formed on the sliding surface 12a side of the fixed blade 12. The concave portion 17 is formed in parallel with forming the outline of the fixed blade 12. That is, only the sliding surface side is dissolved with the etching liquid in the plate thickness direction of the stainless plate material as the etching material, and the other plate surface is coated with the resist film.
In this way, when the contouring of the fixed blade 12 is completed by performing the touching from one surface, about half of the plate thickness is melted to obtain the concave portion 17 composed of the shallow concave. The depth of the recess 17 in this example was about 0.5 mm. A pair of protrusions 18 projecting from the holder 16 are provided in the recess 17.
Protrudes through the through hole 12c of the fixed blade 12. The through holes 12c are formed on the front and back surfaces of the corresponding portion, the resist film 2
It is formed by touching the pattern portion where 5 does not exist in the plate thickness direction. Note that FIG. 1A is a plan view of the fixed blade 12 of this embodiment as viewed from the sliding surface 12a side.
1B is a sectional view taken along the line BB of FIG.

The recess 17 has a through hole 45 formed by the same method as the through hole 12c. As shown in FIGS. 1 and 4, the through holes 45 are formed in a row in the left-right direction with the through hole 12c as a reference. That is, the through holes 12c and the through holes 45 are arranged in a straight line. As a result, when the concave portion 17 is formed in the fixed blade 12,
Since the bending stress (arrow in FIG. 16) that tends to bend around the axis along the axis orthogonal to the left-right direction can be reduced, the local sliding contact between the fixed blade 12 and the movable blade 13 can be prevented, and this As a result, the hair, which is the object, can be cut reliably and appropriately.

Further, since the through hole 12c is used as the through hole 45 for preventing bending stress, it is advantageous in terms of ensuring strength. In other words, forming the through holes 12c for the protrusions 18 in a region other than the recesses 17 increases the total area of each through hole, which inevitably reduces the strength. However, the through holes 12c are formed in the recesses 17. This is because the total area of each through hole can be reduced. In addition, since the through holes 12c and the through holes 45 are arranged in a straight line, it is possible to efficiently and uniformly prevent bending stress on the comb-shaped blades 15 arranged in the left-right direction.

The movable blade 13 has a total thickness dimension of 0.4, for example.
It consists of a 57 mm plate and its front end is
A plurality of comb-shaped blades 20 whose width is gradually narrowed toward the tip side are arranged in the left-right direction. The movable blade 13 is formed by caulking a caulking projection 21b provided on the movable blade fixed base 21 through a through hole 13c provided in the movable blade 13,
It is fixed to the movable blade fixing base 21. One end of the torsion coil spring 14 is locked to the movable blade fixing base 21 (see FIG. 2). Then, the pressing biasing force of the torsion coil spring 14 is transmitted to the movable blade 13 via the movable blade fixing base 21.

The movable blade 13 is provided with an escape hole 47 for the slide piece (guide body) 22 made of synthetic resin,
The slide piece 22 is formed in the clearance hole 47 by, for example, outsert molding. The slide piece 22 is provided with a pair of laterally long guide grooves 22a into which the tips of the protrusions 18 are fitted. Movable blade 13
Also in the same manner as the fixed blade 12, the outline and the through hole 13
c, the escape hole 47 is formed by an etching method.

The movable groove 13 is guided and supported by the guide groove 22a and the protrusion 18 so as to be reciprocable only in the left-right direction. Further, since the protrusion 18 projects through the through hole 12c of the fixed blade 12, the fixed blade 12 is firmly fixed to the holder 16 by the protrusion 18. Further, the protrusion 18 has an effect of preventing positional displacement when the caulking protrusion 21b is caulked.

The slide piece 22 may be fixed to the movable blade 13 by welding. The guide groove 22a may be a through hole. Instead of providing the slide piece 22, the guide groove 22a may be directly provided on the movable blade fixing base 21, and the protrusion 18 may be fitted into the guide groove 22a through the clearance hole of the movable blade 13. The protrusions 18 may be provided on the fixed blade 12.

The lower surface of the slide piece 22 is, as shown in FIG. 6, a sliding surface 13 of the movable blade 13 with the fixed blade 12.
Although it slightly protrudes from the a side to the fixed blade 12 side, the lower surface of the slide piece 22 is in the recess 17 of the fixed blade 12, and the contact between the slide piece 22 and the fixed blade 12 is prevented.

The through hole 12c and the through hole 45 are the through holes 12
The two may be communicated with each other, without considering the use in crimping. That is more effective in preventing bending stress.

As shown in the above specific numerical values, the movable blade 1
3 is thinner than the fixed blade 12. The reason is,
This is to reduce the vibration during reciprocating movement as much as possible by reducing the weight of the movable member. Further, by forming it thin, the movable blade 13 becomes supple and easily adheres to the fixed blade 12.

After the movable blade 13 is formed by an etching method, a curved portion or a bent portion is formed by pressing at a middle position in the front-rear direction. Specifically, FIG.
As shown in (a), a fixed receiving jig 48 having an arc surface (a receiving jig having a bent surface is used when forming a bent portion on the movable blade 13) is movable in the direction of the arrow. By pressing with a pressing jig 49 having a U-shaped cross section from above and below, the movable blade 13 is processed so that the cross section in the front-rear direction is convex upward. The ridgeline of the receiving jig 48 is located at the one-dot chain line portion in FIG. FIG. 15B is a sectional view schematically showing the movable blade 13 after pressing. In the figure, X is the front-rear length of the movable blade 13, which is about 30 m in the embodiment.
m. In the figure, Y is the maximum bending point (or bending point) of the upward convex portion with respect to the reference line connecting the front end and the rear end of the movable blade 13.
10 μ in the embodiment.
It is set to m to 20 μm.

The problem with the conventional movable blade is that, when the movable blade 13 is mounted on the fixed blade 12 side and the movable blade 13 is pressed by the spring 14, the movable blade 13 is necessarily thin as described above. Since it has to be formed, the movable blade 13 is curved so as to be convex downward due to the pressing biasing force, and there is a slight gap on the side of the comb-shaped blade 15 to reduce the cutting ability. I was there. On the other hand, if the spring pressure is reduced, the downward convex curvature is reduced, but the pressing force applied to the comb-shaped blades 15 and 20 is reduced and the cutting ability is reduced. Therefore, as described above, in the movable blade 13,
By providing an upwardly convex curved portion or a bent portion having a bent line portion (ridge line portion of the one-dot chain line in FIG. 5) in the same direction as the axis along the left-right direction of the movable blade 13, the strength against bending is increased and the spring is used. Even if a pressing biasing force is applied, it is difficult to deform, so that there is no lifting phenomenon on the side of the comb-shaped blade 15 and an appropriate pressing force can always be applied, and a reduction in cutting force can be eliminated. Moreover, since the contact pressure at the comb-shaped blades 15 and 20 can be increased, the cutting ability is further improved. Of course, if the pressing biasing force is applied, it will be slightly deformed, but in that case, the value of the bending in the press working so as to maintain the degree of bending at least to the horizontal position (Fig. 15 (b)).
Y value) or the pressing force of the spring must be set. FIG. 6, which shows a sectional view after the blade unit is assembled, shows a state in which the movable blade 13 is bent by the pressing biasing force of the spring 14 and the movable blade 13 is kept horizontal in the front-rear direction. Of course, it may be curved or bent in a slightly upward convex shape, which is convenient for increasing the contact pressure of the comb-shaped blades 15 and 20.

By the above-mentioned etching method, the left and right side surfaces of each comb-shaped blade 15 of the fixed blade 12 are, as shown in FIG.
Edge portions 27 are formed so as to project at positions where the dimension up to the sliding surface 12a is shorter than the dimension up to 2b. The left and right side surfaces of each comb-shaped blade 15 are formed in a concave shape between the sliding surface 12a and the edge portion 27 and between the edge portion 27 and the open surface 12b.

That is, in the resist film 25 forming the comb-shaped blades 15 of the fixed blade 12, the gap L1 between the adjacent comb-shaped blades 15 on the open surface 12b side is the sliding surface 1 as shown in FIG.
It is 1.5 times the interval L2 between the adjacent comb-shaped blades 15 on the 2a side. When the etching solution is sprayed on the plate material on which the resist film 25 is formed, the open surface 12b side and the sliding surface 12 are formed.
Etching progresses while simultaneously recessing in a mortar shape from both the a side.

At this time, since the distance L1 on the open surface 12b side is larger than the distance L2 on the sliding surface 12a side, the degree of progress of etching on the open surface 12b side becomes larger than that on the sliding surface 12a side. A concave curved surface formed from the open surface 12b side,
The boundary with the concave curved surface formed from the sliding surface 12a side is located closer to the sliding surface 12a. This boundary position is the position where the edge portion 27 is formed.

By this etching, the comb-shaped blades 15 of the fixed blade 12 are formed with sharp-edged cutting edges 28 on the left and right sides on the sliding surface 12a side. In the comb-shaped blade 15, as shown in FIG. 1, the width at the forming position of the edge portion 27 and the width at the forming position of the cutting edge 28 are substantially equal to each other, or the edge portion 2 is formed.
The width of the formation position of the cutting edge 28 is slightly narrower than the width of the formation position of 7.

The resist film 25 forming the comb-shaped blade 20 of the movable blade 13 is, for example, as shown in FIG. 8, the adjacent comb on the open surface 13b side which is the surface opposite to the sliding surface 13a with the fixed blade 12. The distance L3 between the blades 20 is set to be three times the distance L4 between the adjacent comb blades 15 on the sliding surface 13a side. When the etching solution is sprayed on the plate material on which the resist film 25 is formed, the left and right side surfaces of the comb-shaped blade 20 are respectively formed in a concave shape, but the degree of progress of etching on the open surface 13b side is higher than that on the sliding surface 13a side. Since it is considerably large, the boundary between the concave curved surface formed from the open surface 13b side and the concave curved surface formed from the sliding surface 13a side is located substantially on the sliding surface 13a side. However, there is no edge at the boundary here.

By this etching, the comb-shaped blades 20 of the movable blade 13 are formed with sharp-edged cutting edges 29 on the left and right sides on the sliding surface 13a side. As shown in FIG. 9, the angle α of the cutting edge 29 is, for example, 60 °, which is smaller than the angle β of the cutting edge 28 of the comb-shaped blade 15 of the fixed blade 12. Comb blade 15
The angle β of the blade edge 28 is 80 °, for example.

As shown in FIG. 10, the tip of each comb-shaped blade 15 of the fixed blade 12 is polished or etched in an inclined shape from the open surface 12b side to the sliding surface 12a side.
As shown in FIG. 11, the degree of narrowing of the width W1 of the comb-shaped blade 15 on the open surface 12b side is larger than the degree of narrowing of the width W2 at the formation position of the edge portion 27. As a result, the side that comes into contact with the skin, that is, the open surface 12 of the comb-shaped blade 15
Prevent the edge of the tip on the b side from getting caught in the skin,
The hair 9 can be scraped off smoothly, and the hair 9 can be cut more reliably and appropriately.

As shown in FIG. 10, the tip of each comb-shaped blade 20 of the movable blade 13 is polished or etched in an inclined shape from the open surface 13b side toward the sliding surface 13a side. Further, as shown in FIG. 5 and FIG. 12, the left and right widths of the tip portion 20a of the comb-shaped blade 20 on the sliding surface 13a side are equal, and the left and right blade edges 29 are substantially parallel. As a result, the hair that has entered between the adjacent comb-shaped blades 20 will be
It prevents it from coming out diagonally along the.

Each sliding surface 1 of the fixed blade 12 and the movable blade 13
At the base end of the comb-shaped blades 15 and 20 on the side of 2a and 13a, as shown in FIGS.
1 are formed respectively. These oil sump recesses 10
Numeral 11 is formed by an etching method when forming the outline of the fixed blade 12 and the movable blade 13. Further, the fixed blade 12 and the movable blade 13 are formed not only by the comb-shaped blades 15 and 20 but also by the outline method, through-holes, dents and the like by the etching method.
That is, the entire fixed blade 12 and the movable blade 13 are processed by forming a flat plate-shaped stainless steel plate material or the like by the etching method as described above, and can be made thinner than the case where these are formed by press working, Little distortion. As a result, the compact shear blade 5 can be provided.

In FIGS. 1 and 4, minute recesses 50 and 51 (not through holes) scattered on the sliding surface 12a.
Is provided to further reduce the sliding resistance.

As the movable blade 13 reciprocally slides to the left and right with respect to the fixed blade 12, the hair 9 has the tip 28 of the comb-shaped blade 15 of the fixed blade 12 and the movable blade 13 as shown in FIG.
It is cut while being sandwiched by the blade edge 29 of the comb-shaped blade 20. At this time, since the hair 9 is supported in a substantially straight state by the edge 28 and the edge portion 27 of the comb-shaped blade 15 of the fixed blade 12, the movable blade 13 and the fixed blade 12 are fixed to the hair 9.
Bite at almost right angle. Therefore, the hair 9 will not be inclined and will not escape from between the adjacent fixed blades 12, and the hair 9 can be cut reliably.

[Brief description of drawings]

FIG. 1 is a view showing a fixed blade according to the present invention.

FIG. 2 is an overall cross-sectional plan view of a clipper to which the shear blade of the present invention is applied.

FIG. 3 is a vertical side view of the entire hair clipper.

FIG. 4 is a plan view of a state in which a fixed blade is attached to a holder as seen from a sliding surface side.

FIG. 5 is a bottom view seen from the sliding surface side with the movable blade attached to the movable blade fixed base.

FIG. 6 is a longitudinal sectional view mainly showing the relationship between a protrusion on the fixed blade side and a slide piece on the movable blade side.

FIG. 7 is a sectional view for explaining etching processing of a fixed blade.

FIG. 8 is a cross-sectional view for explaining etching processing of a movable blade.

FIG. 9 is a cross-sectional view showing angles of fixed blades and movable blades.

FIG. 10 is a side view showing the tips of the fixed blade and the movable blade.

FIG. 11 is an enlarged view of the comb-shaped blade of the fixed blade as seen from the open surface side.

FIG. 12 is an enlarged view of the comb-shaped blade of the movable blade viewed from the open surface side.

FIG. 13 is a cross-sectional view illustrating a cut state of hair.

14 is a cross-sectional view taken along the line AA in FIG.

FIG. 15 is a schematic view showing a movable blade pressing process.

FIG. 16 is a diagram showing bending stress of a plate blade.

[Explanation of symbols]

5 shear blades 9 hair 12 fixed blades 12a Sliding surface 12b open side 12c through hole 13 movable blades 13a Sliding surface 13b open side 15 Fixed blade comb blade 17 recess 18 protrusions 20 Movable blade comb blade 22 slide pieces 27 Edge 28 Fixed blade edge 29 Blade edge of movable blade 45 through hole

Claims (5)

[Claims] 1. A fixed blade 12 in which a large number of comb-shaped blades 15 are arranged in the left-right direction, and a movable blade in which a large number of comb-shaped blades 20 are arranged in the left-right direction to reciprocally slide in the left-right direction with respect to the fixed blade 12. 1
3, the fixed blade 12 and the movable blade 13 are each formed by an etching method, and at least one of the sliding surfaces of the double blades 12 and 13 is a recess for avoiding sliding contact with a sliding partner. 1
7. A shear blade characterized in that a through hole 45 is formed in the recess 17 while forming 7. 2. The shear blade according to claim 1, wherein the through holes 45 are arranged in a row in the left-right direction. 3. A through hole 12c for inserting a projection 18 is arranged in a recess 17 formed on the sliding surface 12a side of the fixed blade 12, and a movable groove 13 is provided with a guide groove 22a extending in the left-right direction. The guide body 22 has is fixed, and the movable blade 13 is guided so as to reciprocate only in the left-right direction with respect to the fixed blade 12 by fitting the projection 18 into the guide groove 22a. The shear blade according to claim 1 or 2. 4. The shear blade according to claim 1, wherein the through holes 45 are arranged in rows in the left-right direction with reference to the through holes 12c through which the protrusions 18 are inserted. 5. The shear blade according to any one of claims 1 to 4, wherein the movable blade 13 is curved or bent toward the fixed blade 12 side.