JPH07108481B2 - Shearing machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shearing machine, and more particularly to a shearing machine for cutting a steel bar, which prevents abrasion of the blade and hardly causes burrs on the cut surface of the steel bar. is there.

[0002]

2. Description of the Related Art A steel material shearing machine that cuts or punches a steel material is used in a steel material processing operation in construction work or machine fabrication. This type of shearing machine is configured to mainly shear a steel bar such as a reinforcing bar by a pair of fixed blades and movable blades, or to punch a plate material such as a steel plate mainly by a die and a punch. , A portable rebar cutter, a portable puncher, and the like (see, for example, JP-A-3-189022).

The applicant of the present invention, in such a shearing machine, forms a concave portion provided with an internal thread in each of a fixed blade fixed to a casing and a movable blade attached to a tip of a piston rod, and a full screw bolt or the like. Has proposed a hydraulically operated cutter for cutting a threaded steel bar, which is configured so that the threaded steel bar can be smoothly sheared (Japanese Patent Application No. 1-93035 (Japanese Utility Model Publication No. 3-33019). According to
When shearing a steel bar with a thread, the entire outer ring of the steel bar engages with the recesses of the fixed blade and the movable blade that have a shape complementary to this, and the male screw of the steel bar matches the female screw of the fixed blade and the movable blade. To do. Therefore, the cutter can shear and cut the threaded steel bar without crushing the male thread of the steel bar.

[0004]

However, it has been found that in such a cutter, when the threaded steel bar or the like is repeatedly cut, the blade is worn out relatively early.
Further, so-called burr is likely to occur on the cut surface of the steel bar, which is a problem in securing a smooth and accurate end surface of the steel bar.

The present invention has been made in view of the above points, and an object of the present invention is to prevent a blade from being worn and to prevent a burr on a surface to be cut of a steel bar. To provide.

[0006]

Means and Actions for Solving the Problems The present inventor has found that the abrasion of the blade and the occurrence of burrs on the surface to be cut have a shearing structure in a conventional steel bar shear cutter, that is, a steel bar cantilevered by a fixed blade. As a result of intensive research and development efforts, the following shearing machine was developed based on the knowledge that it has a shearing structure that presses the movable blade.

That is, the present invention has a movable blade attached to the front end portion of the piston rod and a fixed blade attached to the main body, and the fixed blade substantially has the outer shape of the threaded steel bar to be cut. with a recess having a shape complementary, concave portion, about the shearing machine having a corresponding internal thread and external thread of said bars
It Basically, according to the present invention, the movable blade has a cutting edge portion whose front end portion is pressed against the steel bar when the movable blade is advanced, and the fixed blade includes left and right fixed blade portions. And a slit disposed between the fixed blade portions, the slit is opposed to the cutting blade portion, and is positioned at a position to accommodate the cutting blade portion when the cutting blade portion advances, The fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions to cut the steel bar .

According to the shearing machine having the above construction, the fixed blade portion constitutes a fulcrum for supporting the steel bar at two points, and the movable blade presses the steel bar between the fulcrums. The steel bar is supported in a very stable state, and the steel bar does not have the axial clearance as seen in the case of cantilever support. Therefore, since it is formed on the fixed blade portion, unnecessary lateral force does not act on the screw, and the wear of the threads of the female screw is prevented. Moreover, since the escape of the steel bar does not occur, burrs do not occur on the cut surface of the steel bar. Furthermore, since female screws are provided in the recesses on the left and right fixed blades,
It is possible to position the threaded steel bar on the female screw of the fixed blade and to position the steel bar at a predetermined position of the shearing machine body, and then cut the steel bar with the movable blade. Furthermore, the present invention
The center axis of the concave part of each fixed blade is the width of the fixed blade.
It is inclined at a certain angle to the adaxial line.
Allows the threads of the female thread in the recess to
It has sufficient wall thickness at the adjacent screw ends. Therefore,
The threads near the inner surface of the slit are not
Durable and able to withstand repeated shearing work
It

According to another feature of the present invention, the recess
Female threads have flat tops on each thread, which
Therefore, damage or crushing of the thread crest is prevented. Moreover,
The sidewall defining the slit is located at the top of the thread.
This causes burrs on the cut surface and slippage.
The wear of the threads of the recess adjacent to the
It

In a preferred embodiment of the present invention,
The cutting edge portion has an inner peripheral surface that abuts the outer periphery of the steel bar.
Has an arc-shaped recess, and the slit faces the recess.
To do. According to the shearing machine having such a configuration, the recess of the movable blade abuts the outer circumference of the steel bar on the side opposite to the fixed blade and presses it toward the fixed blade. Therefore, the pressing force for shearing is applied to the steel bar relatively evenly, so that large shear strain is unlikely to occur in the steel bar. Further, since female screws are provided in the recesses of the left and right fixed blade portions, the steel bar with a screw is positioned on the female screw of the fixed blade and the steel bar is positioned at a predetermined position of the shearing machine body, and then the movable blade Steel bars can be cut.
Thus, a good threaded steel bar can be cut with a shearing machine. In one embodiment of the present invention, a female thread corresponding to the male thread of the steel bar is formed in the recess of the movable blade. In the movable blade having such a structure, the male screw of the steel bar and the recess of the movable blade are smoothly engaged with each other in a form complementary to each other and maintain a stable relative position. Thus, the movable blade contributes to prevention of axial displacement of the steel bar and prevention of burr on the cut surface.

According to the present invention, the slit is
A screw thread that is inclined with respect to the fixed blade at an angle that is set to be substantially the same as the lead angle of the female screw of the recess and that is close to the side wall of the slit extends substantially parallel to the slit. Further, the side wall portion located between the exposed end surface of the fixed blade and the bottom portion of the recess is not tapered and extends substantially parallel to each other. Thus, the threads proximate to the side wall can ensure a uniform and sufficient thickness over the entire circumference of the recess, have the desired durability against wear and withstand repeated shearing operations.

From another point of view, in the present invention, a broken material passage is formed in the fixed blade supporting portion of the main body which supports the fixed blade, the broken material passage communicates with the slit, and the slit is The first left and right adjacent to the exposed end surface of the fixed blade
It is defined by a side wall and left and right second side walls arranged between the first side wall and the broken material passage, and a distance between the second side walls is a distance between the first side walls. the atmosphere than
Yes. From still another aspect, according to the present invention, the fixed blade includes a hollow portion that communicates with a breakage hole for a broken material disposed in the shearing machine body, and the hollow portion communicates with a bottom portion of the slit. The side wall that defines the slit is tapered, and the side wall forms a broken material discharge path that expands toward the hollow portion. According to this structure, the broken material generated by the shearing work can smoothly pass through the slit into the broken material passage or the hollow portion and the pit, so that the conventional broken material can be reliably prevented from remaining in the slit. Thus, the residual breaking material spreads the slit by the subsequent shearing work, thereby avoiding the occurrence of cracks near the bottom of the slit. More preferably, a curved portion having a small diameter is provided at the intersection of the side wall and the bottom wall of the slit, whereby the induction of such cracks is reliably prevented.

Further , according to the present invention, the base portion of the fixed blade is formed into a cylindrical shape as a whole, and an end surface of the base portion abuts on a shoulder portion formed in the drop hole, so that the fixed blade is subjected to shearing work. Substantially all of the load acting on is supported by the reaction forces exerted on the end faces of the shoulder and the base. With such a configuration, breakage or damage of the collar or the collar provided on the fixed blade can be avoided in advance.

From another aspect, according to the present invention, the concave portion
The central axis line of the pair is perpendicular to the central line of the slit.
And tilt at a predetermined angle, and the center line of the slit
The angle between the center axis of the recess and the central axis is less than 90 degrees.
The slit is the lead angle of the male thread of the steel bar.
Oriented to form a directional cutting surface in the steel bar. Further
Preferably, the axis of the recess and the perpendicular of the slit are
The predetermined angle to be formed is set to 3 to 5 degrees.

In another embodiment of the present invention, the clearance between the width of the slit and the cutting edge portion of the fixed blade is 0.3 to 0.8 mm, more preferably 0.4 m.
It is set to m to 0.7 mm. As a result, distortion or a step on the cut surface of the steel bar to be cut and generation of burrs on the cut surface are prevented. It has been found that this clearance value can be preferably adopted regardless of the material of the steel bar to be cut.

More preferably, the distance between the center line of the screw thread adjacent to the side wall and the side wall is 0 to 0.3 m.
It is set to a value within the range of m. Thereby, it is possible to avoid the occurrence of burrs on the cut surface of the steel bar to be cut, and to prevent the damage or crushing of the top of the screw thread adjacent to the side wall, while cutting the steel bar to be cut having different diameters by the common movable blade. It will be possible.

From another point of view, the present invention has a movable blade attached to the front end portion of the piston rod and a fixed blade attached to the main body, and the fixed blade substantially has the outer shape of the threaded steel bar to be cut. In a cutting tool of a shearing machine, which has a recess having a shape complementary to that of the steel bar, the movable blade is pressed against the steel bar when the movable blade advances. The fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, and the slit is in the direction of the lead angle of the female screw of the recess. The side wall extending and defining the slit is located at or near the top of the thread of the internal thread of the recess, and the slit defines a cutting edge portion of the movable blade when the movable blade advances. Width that can accommodate the cutting edge portion to accommodate In use, the fixed blade portion supports the steel bar on both sides of the movable blade, the movable blade presses the steel bar between the left and right fixed blade portions to cut the steel bar. A cutting tool for a shearing machine is provided.

The cutting tool constructed as described above is used in a shearing machine.
Cutting work for steel bars that are mounted and have threads such as full-thread bolts
When it is used for, it is possible to prevent the blade from being worn away, to prevent distortion or steps on the cut surface of the steel bar, and to eliminate the occurrence of burrs on the cut surface. In a preferred embodiment of the present invention, the cutting edge portion abuts on the outer circumference of the steel bar.
Has an arcuate depression with an inner peripheral surface
The diameter is set larger than the radius of the steel bar, and the
Is substantially aligned with the direction of the lead angle of the female thread of the recess.
Extend in parallel.

In a preferred embodiment from the practical point of view of the present invention, the shearing machine is a shearing machine mainly for punching a steel material, and the movable blade and the fixed blade are punches and dies. Is replaced with a movable blade and a fixed blade.
Such a shearing machine makes it possible to carry out two related operations with the same model, and in view of its practicality, it has an extremely high added value and brings great convenience.

[0020]

The preferred embodiments of the shearing machine according to the present invention will be described in detail below with reference to the accompanying drawings. Figure 1
FIG. 3 is a vertical sectional view of a shearing machine according to an embodiment of the present invention. The shearing machine shown in FIG. 1 is mainly configured as a so-called portable puncher for punching a steel plate. The shearing machine 1 includes a portable handle 2, an electric motor 3 supported by the portable handle 2, a pump unit 4 connected to the electric motor 3, and a hydraulic cylinder unit 5 that constitutes a hydraulic operating mechanism together with the pump unit 4. And a jaw-shaped head or jaw 6 extending forward from the hydraulic cylinder portion 5.

The portable handle 2 is provided with a trigger switch 21 for manually controlling the operation of the electric motor 3 and a grip portion 22 held by an operator with his / her fingers. The electric motor 3 includes an output shaft 30 extending into the pump unit 4, and the output shaft 30 has a cam shaft 31 at its front end portion. The center axis of the cam shaft 31 is slightly eccentric with respect to the rotation axis of the output shaft 30. A needle bearing 32 is arranged on the outer periphery of the cam shaft 31 concentrically with the cam shaft 31.

A housing 40 of the pump portion 4 is connected to the electric motor 3, and an oil tank 42 for containing hydraulic oil is formed in the pump housing 40. A supply port 48 penetrating the housing 40 is formed above the oil tank 42, and a plug 49 is screwed into the supply port 48. The pump piston 41 that constitutes each pump unit 4 a of the pump unit 4 is in sliding contact with the outer peripheral surface of the needle bearing 32.
The pump piston 41 is constantly operated by the spring 44.
It is biased upward in the figure, that is, toward the needle bearing 32. An oil passage 43 communicating with the oil tank 42 is arranged adjacent to the lower end of the pump piston 41, and an on-off valve 45 is arranged in an oil passage 47 between the pump unit 4 and the hydraulic cylinder device 5. The on-off valve 45 is biased toward the pump piston 41 by the spring 46, and normally closes the oil passage 47.

The hydraulic cylinder device 5 includes a cylinder case 5
0, a piston 51 reciprocally arranged in the cylinder case, and hydraulic chambers 52 and 53 defined on both sides of the piston 51, respectively. The hydraulic chamber 52 has an oil passage 47.
And when the release valve device 55 is opened,
It can communicate with the release oil passage 54. Release valve device 55
Is opened when the piston 51 moves forward by a predetermined distance, and connects the hydraulic chamber 52 and the release oil passage 54.
As a result, the hydraulic oil in the hydraulic chamber 52 is released into the release oil passage 5
The oil is returned to the oil tank 42 via 4.

Further, an oil storage device is provided in the auxiliary handle 2a for absorbing or supplementing excess hydraulic oil or insufficient hydraulic oil caused by the difference in volume change rate between the hydraulic chamber 52 and the hydraulic chamber 53. The oil system includes an oil storage chamber 55a that communicates with the hydraulic chamber 53 via an oil passage 56, and an air chamber 55b that is separated from the oil storage chamber 55a by a flexible film 55c. The air chamber 55b is open to the atmosphere.

A return spring 57 for urging the piston 51 backward and a piston rod 58 extending forward from the piston 51 are arranged in the hydraulic chamber 53. The return spring 57 always holds the piston 51 in the most retracted position. Also, the piston rod 58
Penetrates the hydraulic chamber 53, and also penetrates the cylinder connecting portion 60 of the jaw 6 that defines the front end of the hydraulic chamber 53. The jaw 6 extends downward from the cylinder connecting portion 60 and extends forward in a substantially hook shape.

The shearing machine 1 is generally used for punching a steel plate. In this case, a punch is attached to the tip of the piston rod 58, and a fixed die is provided at the front end of the jaw 6 so as to face the punch. Mounted as you would. However, the shearing machine 1 is capable of cutting a steel bar, in particular a threaded steel bar W, in which case a movable blade 10 is attached to the front end of the piston rod 58, as shown in FIG. A fixed blade 7 facing the blade 10 is attached to the front end portion of the jaw 6. When the movable blade 10 advances due to the extension of the piston rod 58, the fixed blade 7 cooperates with the movable blade 10 to shear the steel bar W inserted between the movable blade 10 and the fixed blade 7, and the steel bar W. Is cut substantially perpendicular to its axis.

2, 3 and 4 are a perspective view, a plan view and a side view showing the front end portion of the shears 1. Also, FIG.
FIG. 4 is an elevation view of the fixed blade 7. As shown in FIGS. 2 to 4, the cutting edge portion 11 of the movable blade 10 protruding from the piston rod 58 has a substantially rectangular parallelepiped shape having a flat rectangular front end surface, and is embedded in the piston rod 58. 10
Is integrally supported by the base portion 12. The base 12
Is of the same form as the base of a punch used for punching a steel plate or the like, and the movable blade 10 is compatible with the punch. The base 12 is fixed to the piston rod 58 by the fixing screw 13.

The fixed blade 7 is arranged on the opposite side of the movable blade 10, and the base portion 74 of the fixed blade 7 is embedded in the jaw 6.
The base portion 74 has the same shape as the base portion of the die used for punching a steel plate or the like, and the fixed blade 7 is compatible with the die. The base 74 is fixed to the jaw 6 by a fixing screw 75. The fixed blade 7 includes a pair of left and right fixed blade portions 71, 71 integrally supported by the base portion 74.
The fixed blade portions 71, 71 are spaced apart from each other by a predetermined distance, and the slits 72 extending in the vertical direction have fixed blade portions 71, 71.
It is formed between 71. The slit 72 is positioned at a position that exactly faces the cutting blade portion 11, and accommodates the cutting blade portion 11 when the cutting blade portion 11 advances. The slit 72 has substantially the same width as the cutting edge portion 11 of the movable blade 10, and the left and right inner side surfaces that define the slit 72 slide-contact with each side surface of the cutting edge portion 11 when the cutting edge portion 11 advances. Close.

Each fixed blade portion 71 is provided with a substantially semicircular concave portion 73, and the concave portion 73 has a form complementary to the outer shape of the bar steel W with a screw and also has a female screw corresponding to the external thread of the steel bar W. As shown in FIG. 5, the axes of the recesses 73, 73 are inclined at a predetermined angle α with respect to a vertical line with respect to the slit 72, that is, the widthwise axis of the fixed blade 7.
The angle α is preferably set to be substantially the same as the lead angle of the female screw, for example, set to an angle of 3 ° to 5 °.

FIG. 6 is a partially enlarged sectional view of the screw formed in the recess 73. The female thread of the recess 73 has a flat top at each thread, and each thread has a trapezoidal cross section. The cross-sectional property of such a screw thread is formed by setting the prepared hole borering diameter before tapping to be slightly larger in the female screw manufacturing process. Next, the operation of the shearing machine 1 will be described.

By pulling the trigger switch 21 of the portable handle 2 with fingers, the shears 1 is started. The electric motor 3 is operated and the output shaft 30 and the cam shaft 31 are rotated. Needle bearing 3 located on the outer periphery of the cam shaft 31
2 rolls to reciprocate the pump piston 41 which is in sliding contact with the outer periphery of the needle bearing 32. Thus, the pump unit 4 feeds the hydraulic oil of a predetermined pressure to the hydraulic chamber 52 of the hydraulic cylinder device 5.

As the pressure in the hydraulic chamber 52 increases, the piston 51
Is moved forward (to the left in FIG. 1) while resisting the elastic force of the return spring 57. As a result, the piston rod 58 and the movable blade 10 are moved forward, and the movable blade 10
Cooperates with the fixed blade 7 to shear the steel bar W. Piston 5
When 1 is moved forward by a predetermined distance, the release valve device 55 is opened, and the hydraulic chamber 52 communicates with the release oil passage 54.
The hydraulic oil in the hydraulic chamber 52 passes through the release oil passage 54 and then the oil tank 4
2, the piston 51 is retracted to the initial position shown in FIG. 1 by the return spring 57, and the release valve device 55 is closed. The basic operation mode of the shearing machine is disclosed in detail in Japanese Patent Laid-Open No. 3-189022, etc., and therefore, by citing the publication, further detailed description will be omitted, and the following description will be omitted. The operation of the blade 10 and the fixed blade 7 will be described in detail.

About half of the steel bar W has a fixed blade portion 71
The male screw portion which is housed in the concave portion 73 and is formed in this half portion is screwed into the female screw of the concave portion 73. By the forward movement of the movable blade 10, the front end surface of the movable blade 10 is pressed against the surface of the steel bar W facing the movable blade 10. Left and right fixed blade parts 71,
71 supports the pressing force of the movable blade 10 on both sides of the movable blade 10. Therefore, the steel bar W is supported by the symmetric fulcrums formed by the fixed blade portions 71, 71, and the movable blade 10 presses the part of the steel bar W located between the fulcrums toward the fixed blade 7. The movable blade 10 and each fixed blade portion 71 are
The steel bar W is sheared together in cooperation with each other, that is, between the fulcrums of the steel bar W, that is,
The portion of the steel bar W located in the slit 72 is punched out. Thus, the steel bar W is cut along the left and right inner surfaces of the slit 72, and the steel bar portions located on both sides of the movable blade 10 are
A cut surface is formed that is substantially parallel to the lead of the male screw. The punched portion between the steel bar portions is discharged through the slit 72 and the hollow portion of the base portion 74.

The male thread of the steel bar W is pressed by the fixed blade 7 during shearing, but since it is accurately screwed into the female thread of the recess 73, the thread of the steel bar W is not damaged. Further, the external thread of the steel bar W is pressed against the front end surface of the movable blade 10 during shearing, but since this part is punched out, it does not remain in each bar steel part after cutting, and therefore there is substantially no hindrance. . in this way,
The shearing machine 1 includes a movable blade 10 compatible with a punch,
A fixed blade 7 compatible with the die, and the cutting edge portion 11 of the movable blade 10 has a flat rectangular front end face.
Is a pair of left and right fixed blade portions 71, 71 and the fixed blade portion 7
1 and 71, and the slit 72 is positioned at a position that exactly faces the cutting edge portion 11, and the slit 72 and the cutting edge portion 11 move forward when the cutting edge portion 11 advances. It has substantially the same width as the cutting edge portion 11 so as to accommodate the sliding contact or the proximity thereof.

According to such a shearing machine 1, the fixed blade portion 7
Reference numerals 1 and 71 form fulcrums that support the steel bar W at two points, and the movable blade 10 is pressed by the steel bar W between the fulcrums. The steel bar W is supported in an extremely stable state, and the steel bar W does not have the axial clearance as seen in the case of the cantilever support structure. Therefore, unnecessary lateral force does not act on the internal thread of the fixed blade portion 71, and the wear of the threads of the internal thread is prevented. Moreover, since the escape of the steel bar W does not occur, burrs do not occur on the cut surface of the steel bar W.

Further, in the shearing machine 1 of the above-mentioned embodiment, since the axis of the concave portion 73 of each fixed blade portion 71 is inclined at a predetermined angle α with respect to the widthwise axis of the fixed blade 7, the concave portion is formed. The thread of the female thread 73 has a sufficient thickness at the thread end adjacent to the inner surface of the slit 72. Therefore, the threads near the inner surface of the slit 72 have sufficient durability against abrasion and can withstand repeated shearing work. Moreover, in the female thread of the recess 73, since the tops of the threads are formed flat, damage or crushing of the tops of the threads is prevented.

Further, in actual work, shearing of a steel bar with a thread is often required in a work associated with so-called punching with a so-called puncher (for example, after drilling a steel material, the steel material is In the shearing machine 1 of the above embodiment, the punch and die of the puncher are replaced with the movable blade 10 and the fixed blade 7, and therefore, the actual work at the site can be handled very well. That is, in the above embodiment, by using the puncher for cutting the steel bar, it is possible to perform two related works by the same model, and in view of its practicality, it has a very high added value and brings great convenience.

7 and 8 are a perspective view and a side view showing a second embodiment of the present invention. 7 and 8,
The same reference numerals are attached to the same members or parts as those in the above-described embodiment. The overall structure of the shears of this example is basically the same as the overall structure of the shears of the above examples,
Description of the entire structure is omitted, and the fixed blade 7 and the movable blade 1
The structure of 0 will be described.

The base portion 74 of the fixed blade 7 is embedded in the jaw 6. The base portion 74 has the same shape as the base portion of the die used for punching a steel plate or the like, and the fixed blade 7 is compatible with the die. The base 74 is fixed to the jaw 6 by a fixing screw 75. The fixed blade 7 includes a pair of left and right fixed blade portions 71, 71 integrally supported by the base portion 74, and the fixed blade portions 71, 71 are separated from each other by a predetermined distance. The slit 72 extending in the vertical direction has a fixed blade portion 7.
It is formed between 1 and 71.

Each fixed blade portion 71 is provided with a substantially semicircular concave portion 73, and the concave portion 73 has a form complementary to the outer shape of the threaded steel bar W, and also has a female thread corresponding to the male thread of the steel bar W. The axes of the recesses 73, 73 are inclined at a predetermined angle with respect to the widthwise axis of the fixed blade 7, for example, the same angle of 3 ° to 5 ° as the lead angle of the female screw.

Movable blade 1 protruding from the piston rod 58
The cutting edge portion 0 of 0 is integrally supported by the base portion 12 of the movable blade 10 embedded in the piston rod 58, and the slit 7
It is facing 2. The base 12 has the same shape as the base of a punch used for punching a steel plate or the like, and the movable blade 10 is compatible with the punch. The base 12 is fixed to the piston rod 58 by the fixing screw 13.

An arc-shaped recess 1 is formed on the front end face of the cutting edge portion 11.
0a is formed. The recess 10a has a radius of curvature equal to or slightly larger than the radius of the steel bar W, and is arranged at a position facing the steel bar W. In use, each fixed blade part 7
The movable blade 10 comes into contact with the steel bar W having a substantially half portion accommodated in the concave portion 73 of No. 1 from the side opposite to the slit 72. The inner peripheral surface of the recess 10a of the movable blade 10 is pressed by the steel bar W,
The left and right fixed blade portions 71, 71 support the pressing force of the movable blade 10 on both sides of the movable blade 10. The movable blade 10 and each fixed blade portion 71 cooperate to shear the steel bar W and punch out the portion of the steel bar W located in the slit 72.

Thus, according to the shearing machine of this embodiment, the steel bar W
The movable blade 10 is formed with an arcuate recess 10a having a radius of curvature equal to or slightly larger than the radius of the bar. The inner peripheral surface of the recess 10a contacts the outer periphery of the steel bar W and presses it toward the slit 72. Therefore, since the pressing force applied by the movable blade 10 is relatively evenly applied to the steel bar W, a large shear strain is unlikely to occur in the steel bar W. Thus, according to the shearing machine of the present example, not only the occurrence of burrs on the cut surface of the steel bar W can be prevented, but also a good finish of the cut surface can be realized.

9 to 14 are views showing a third embodiment of the present invention. FIGS. 9 and 10 are plan views and longitudinal sectional views of a fixed blade and a movable blade around a shearing machine, and FIG. 12 is an elevation view of the fixed blade, FIG. 12 is a partially enlarged view showing the structure of the fixed blade female screw and the slit surroundings, and FIGS. 13 and 14 are partially enlarged views showing the structure of the fixed blade female screw and the slit surroundings. FIG. 9 to 14, the same members or parts as those in the first and second embodiments are designated by the same reference numerals.

As shown in FIGS. 9 and 10, the movable blade 10
Is attached to the tip of the piston rod 58 of the shears,
The fixed blade 7 is attached to the front end portion of the jaw 6 by the movable blade 10
It is attached so as to face with. When the movable blade 10 advances due to the extension of the piston rod 58, the fixed blade 7
In cooperation with the movable blade 10, the threaded steel bar inserted between the movable blade 10 and the fixed blade is sheared, and the steel bar is cut at a substantially right angle to its axis.

As shown in FIGS. 9 and 10, the movable blade 10
The base portion 12 is inserted into the piston rod 58, and is integrally supported by the tip portion of the piston rod 58 by a fixing screw (not shown). The cutting blade portion 11 of the movable blade 10 protruding from the piston rod 58 has an arc-shaped recess 1 on the front end face.
0a is formed, and the radius of curvature R'of the depression 10a is
It has a size equal to or slightly larger than the radius of steel bar W.
It is located at a position facing. More specifically, the radius of curvature R'of the recess 10a is set to be slightly larger than the radius of the 1/2 inch full threaded bolt, and not only the shearing of the 1/2 inch full threaded bolt but also the 3/8 inch. It can also be used for shearing of all screw bolts, and also for shearing of steel bars having a standard diameter of mm. Further, the width T of the cutting edge portion 11 of this example
Is set to 5.3 mm.

Fixed blade 7 arranged on the opposite side of the movable blade 10.
Includes a base portion 74 formed in a generally cylindrical shape, and the base portion 74 is inserted into a drop hole 62 formed in the jaw 6. The end surface of the base portion 74 is in contact with the shoulder portion 64 formed in the drop hole 62. A peripheral groove 75 is formed on the outer surface of the base portion 74. The tip of a fixing screw (not shown) screwed into the jaw 6 engages with the circumferential groove 75, and the fixed blade 7 is held at a predetermined position of the jaw 6.

A hollow portion 76 is bored in the center of the base portion 74, and the hollow portion 76 is open to the drop hole 62 and communicates with the slit 72 that divides the fixed blade 7 into right and left. The drop hole 62 and the hollow portion 76 constitute a broken material discharge path for discharging the broken material punched by the movable blade 10 and the fixed blade 7. Slit 72 extending in the vertical direction
A pair of left and right fixed blade portions 71, 71 integrally supported by the base 74 are disposed on both sides of the fixed blade portions 71, 7 respectively.
The slits 1 are spaced apart from each other by a predetermined distance. The slit 72 is the cutting edge portion 1 of the movable blade 10.
It is positioned at a position that exactly faces 1 and accommodates the cutting edge portion 11 when the cutting edge portion 11 advances.

As shown in FIG. 10, a concave portion 73 is formed in each fixed blade portion 71, and the concave portion 73 is formed in a substantially semicircular shape so as to substantially complement the outer shape of the threaded steel bar. A female thread corresponding to the male thread of the steel bar W is provided on the inner peripheral portion. Both sides of the slit 72 have first side walls 77, 7
7 and second side walls 78, 78. The first side walls 77, 77 extend from the exposed end surface of the fixed blade 7 to the recess 73.
The second sidewalls 78, 78 extending substantially parallel to the bottom of the
Extends from the end portions 79, 79 of the first side walls 77, 77 to the hollow portion 76. The second side wall 78 forms an angle β with the first side wall 77, and the debris discharge passage formed by the second side walls 78, 78 is slightly expanded toward the hollow portion 76. The end portion of the second side wall 78 has a radius of 1 mm.
A small radius of curvature R is attached to the second side wall 78.
Moves smoothly to the bottom wall 78a.

As shown in FIG. 11, the perpendicular line of the recesses 73, 73 to the axis is a predetermined angle γ with respect to the slit 72.
And is inclined. The angle γ is preferably set to be substantially the same as the lead angle of the female screw, and for example, the angle 3 ° 5
It is set to 0 '. As shown in FIG. 12, the first side wall 77 of the slit 72 is close to the thread portion of the female screw,
The thread portion of the portion adjacent to the side wall surface 77 has a wall thickness of about half (t / 2) of the thread width t.

As shown in FIGS. 13 and 14, the recess 73
In the internal thread, each top portion of the thread 80 is formed flat, and each thread 80 has a trapezoidal cross section. In FIG. 13, 1/2
A partially enlarged cross section of a fixed blade 7 suitable for cutting an inch full threaded bolt is shown, and FIG. 14 shows a partially enlarged cross section of a fixed blade 7 suitable for cutting a 3/8 inch full threaded bolt. Has been done.

The pitch P of the thread 80 in FIG. 13 is
Set to 2.1167 mm, thread 8 in FIG.
The pitch P ′ of 0 is set to 1.5875 mm. In addition, the width S of the slit 72 in FIG.
9 mm (2.79 × pitch P), the width S ′ of the slit 72 in FIG. 14 is 5.8 mm (3.65 ×
The pitch P ') is set. Therefore, the slit 72 of the fixed blade 7 and the cutting edge portion 11 of the movable blade 10 shown in FIG.
The clearance (ST = 5.9−5.3) with
6 mm, the slit 72 of the fixed blade 7 shown in FIG.
And the clearance between the cutting edge portion 11 (S'-T = 5.8)
-5.3) is 0.5 mm.

In the female thread formed by the thread 80 and the thread groove 81, the slit 72 is interrupted over the widths S and S ', as shown by the phantom line, and the first part of the slit 72 is formed.
In the portion of the female thread adjacent to the side walls 77, 77, threads 8
0 is located. In FIG. 13, the distance D between the center line of the thread 80 adjacent to the first side wall 77 and the first side wall 77 is preferably set to 0.225 mm.
, The distance D ′ between the center line of the thread 80 adjacent to the first side wall 77 and the first side wall 77 is preferably 0.
It is set to 275 mm.

In the shearing machine of this embodiment having the above-described structure, the second side wall 78 defining the slit 72 is tapered, and the second side walls 78 and 78 are slightly expanded toward the hollow portion 76. Since the broken material discharge path is formed, the broken material generated by shearing can smoothly pass from the slit 72 to the hollow portion 76 and the drop hole 62. Thus, it is possible to surely prevent the conventional fractured material from remaining in the slit 72, and therefore the residual fractured material expands the slit 72 by the subsequent shearing work, thereby cracking near the bottom wall 78a of the slit 72. It is possible to avoid the situation that causes

Further, since a small-diameter R-shaped portion is provided at the intersection of the second side wall 78 and the bottom wall 78a, it is possible to reliably prevent the occurrence of such cracks. Further, the base portion 74 of the fixed blade 7 formed in a generally cylindrical shape does not include a collar or a collar, and the end face is in contact with the shoulder portion 64 of the drop hole 62, which acts on the fixed blade 7 during shearing work. Substantially all of the load exerted is supported by the reaction force generated on the end surfaces of the shoulder portion 64 and the base portion 74. According to the fixed blade 7, it is possible to avoid a situation where the collar or the collar is damaged or damaged due to the shear stress acting on the collar or the collar.

Further, the perpendicular line to the axis of the recesses 73, 73 is inclined with respect to the slit 72 at an angle γ set to be substantially the same as the lead angle of the female screw, and the slit 72
The thread 80 near the first side wall 77 of the slit 72
And extend substantially parallel to. Moreover, the first side wall 77 located between the exposed end surface of the fixed blade 7 and the bottom of the recess 73,
77 extend substantially parallel to each other. Therefore, the thread 80 close to the first side wall 77 can secure a uniform and sufficient thickness over the entire circumference of the recess 73, has a desired durability against abrasion, and withstands repeated shearing work. be able to. Moreover, since the tops of the screw threads 80 are formed flat, damage or crushing of the screw thread tops is reliably prevented.

Further, in the fixed blade 7 (FIG. 13) suitable for cutting all 1/2 inch screw bolts, the slit 72
And the clearance between the movable blade 10 and the cutting edge portion 11 (S-
T) is set to 0.6 mm and the fixed blade 7 (FIG. 14) suitable for cutting 3/8 inch full threaded bolts,
Clearance (S ′ between slit 72 and cutting edge portion 11)
-T) is set to 0.5 mm. According to the knowledge of the present inventor, in the shearing machine having the structure of this example, generally, if the clearance is too small, a distortion or a step is formed on the cut surface of the whole screw bolt, while the clearance is too large. Then, burr will occur on the cut surface of all screw bolts. The present inventor sets the value of the clearance to 0.3 to 0.8 mm, preferably 0.4 mm to 0.7 mm so that the cut surface of the whole screw bolt does not have a distortion or a step, and the cutting is performed. It was found that no burr was generated on the surface. The inventor further has such a clearance value irrespective of the material of the steel bar to be cut, as long as the material of the steel bar to be cut is a stainless steel or a mild steel as long as it is within the above range. Therefore, it was found that the distortion or step of the cut surface and the burr of the cut surface did not occur. Thus, the clearance between the slit 72 and the cutting edge portion 11 of the movable blade 10 is set to 0.3 to 0.8 mm, preferably 0.4 mm to 0.7 mm, whereby the steel bar to be cut is cut. The surface distortion or step and the burr on the cut surface are eliminated. Further, in the above embodiment, the thread 8 adjacent to the first side wall 77.
The distance D between the center line of 0 and the first side wall 77 (see FIG.
3) and D '(Fig. 14) are 0.225mm, 0.275
It is set to mm respectively. A common movable blade 1 for all 1/2 inch screw bolts and 3/8 inch screw bolts
In order to shear with 0, the widths S and S'of the slit 72 should be set to the same width, but the present inventor found a range in which the distances D and D'can be set to substantially the same value. On the other hand, it is in the range of 0 to 0.3 mm. That is, if the value is in the range of 0 to 0.3 mm, the values of the distances D and D'can be preferably set to substantially the same value. When the value exceeding the range, for example, the value of the distances D and D'is set to 0.4 mm, burrs are apt to occur on the cut surface of all screw bolts.
On the other hand, when the values of the distances D and D'are set to a value below the above range, for example, -0.1 mm (that is, the first side is closer to the thread groove 81 than the center of the thread 80 adjacent to the first side wall 77). If the sidewalls 77 are located), repeated shearing operations are likely to cause damage or crushing of the tops of the threads 80. Thus, the first
The center line of the thread 80 adjacent to the side wall 77 and the first side wall 7
The distances D (FIG. 13) and D ′ (FIG. 14) from 7 are set to values in the range of 0 to 0.3 mm, which causes burrs on the cut surface and the top of the thread 80. 1/2 inch full screw bolt and 3/8 while preventing damage or crushing
It becomes possible to cut all inch screw bolts by the common movable blade 10. The present inventors have found that the range of 0 to 0.3 mm is 1/2, 3 /
The same can be applied to the shearing of a full-threaded bolt having a diameter other than 8 inches, or the shearing of a steel bar with a screw (mm unit) having another diameter standard.

Although the preferred embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments, and various modifications or changes can be made within the scope of the invention described in the claims. Needless to say, these are also included in the scope of the present invention. For example, in the above embodiment, the present invention is applied to a so-called puncher, but the present invention can be applied to a cutter or a cutting machine that is a concept including a puncher. For example, the present invention may be applied to a rebar cutter, and the normal movable blade and fixed blade of the rebar cutter may be replaced with the movable blade and fixed blade according to the present invention, respectively.

Further, the recess of the movable blade in the second and third embodiments may be provided with an internal thread corresponding to the external thread of the steel bar with a thread. As a result, the recess of the movable blade and the male screw of the steel bar can be smoothly engaged with each other in a complementary form and can be positioned relative to each other, and the two secure a stable relative position during shearing. Thus, the movable blade will contribute to the prevention of axial displacement of the steel bar and the prevention of burrs on the cut surface, and will realize a better cut surface of the steel bar.

[0060]

According to the basic constitution of the present invention , it is possible to provide a shearing machine for cutting a steel bar with a screw which prevents abrasion of the blade and hardly causes burrs on the surface to be cut of the steel bar. . Further , according to such a shearing machine, since female screws are provided in the recesses of the left and right fixed blade portions, the threaded steel bar is positioned on the female threads of the fixed blade and the steel bar is fixed at a predetermined position of the shearing machine body. The steel bar can be cut by the movable blade after being positioned at. Therefore, without crushing the male thread of steel bar, it is possible to reliably cut the threaded steel bars
It

According to the configuration of the present invention described in claim 1 ,
The thread of the screw formed in the concave portion of the fixed blade portion has a sufficient wall thickness in the vicinity of the inner surface of the slit and has excellent durability against abrasion. Therefore, the fixed blade can withstand repeated shearing operations. Claim 2 or 1
According to the configuration of the present invention described in No. 0 , since each top of the thread of the screw is formed flat because it is formed in the recess of the fixed blade portion, damage or collapse of the thread top is prevented, and The occurrence of burrs on the surface to be cut and the wear of the threads of the recess adjacent to the slit are more reliably prevented.

According to the structure of the present invention described in claim 3 , the screw thread near the side wall can secure a uniform and sufficient thickness over the entire circumference of the concave portion, and has a desired durability against abrasion. It has the property of being capable of withstanding repeated shearing operations. According to the configuration of the present invention described in claim 11 , the distance between the center line of the screw thread adjacent to the side wall and the side wall is 0 to 0.3.
It is set to a value in the range of mm, which avoids the occurrence of burrs on the cut surface of the steel bar to be cut and prevents the damage or crushing of the top of the thread adjacent to the side wall, while cutting the steel bar of different diameters. Can be cut by a common movable blade.

According to the structure of the present invention as set forth in claim 4 or 5 , the side wall defining the slit constitutes a broken material discharge passage in which the side wall is expanded toward the broken material passage of the main body or the hollow portion of the fixed blade. Therefore, it is possible to surely prevent the conventional broken material from remaining in the slit, and thus it is possible to prevent the occurrence of a crack near the bottom of the slit.

According to the twelfth aspect of the present invention, a curved portion having a small diameter is provided at the intersection of the side wall and the bottom wall of the slit, and the occurrence of such cracks is reliably prevented. According to the configuration of the present invention described in claim 6 , since the base portion of the fixed blade does not include the collar or the collar and is formed in a cylindrical shape as a whole, damage or damage to the collar or the collar is avoided in advance. To be done.

According to the configuration of the present invention as set forth in claim 13 , the width of the slit and the clearance between the fixed blade and the cutting edge portion are set to 0.3 to 0.8 mm. Distortion or a step of the cut surface of the steel bar and generation of burrs on the cut surface are prevented. According to the configuration of the present invention as set forth in claim 7 or 14, the thread close to the side wall can secure a uniform and sufficient thickness over the entire circumference of the recess, and has desired durability against abrasion. And can withstand repeated shearing operations. Further, the shearing machine can more reliably prevent burrs on the cut surface of the steel bar. The invention according to claim 8
According to the configuration, the wear of the blade is prevented and the surface to be cut of the steel bar is
A surface to be cut that is resistant to tearing and is good for shearing.
Providing a shearing machine for cutting threaded steel bars that can achieve the finishing of
It becomes possible to serve. The structure of the present invention according to claim 9.
According to the composition, the male thread of the steel bar and the depression of the movable blade are
Engages smoothly in complementary form and maintains a stable relative position
To do. Therefore, the movable blade of the shearing machine is used for axial displacement of the steel bar.
Can be prevented and burr on the cut surface can be prevented.

According to the structure of the present invention described in claim 15, the shearing machine of the present invention enables compatibility between the shearing machine for cutting a threaded steel bar and the shearing machine for drilling a steel material, and the shearing machine for actual work. Since it can be adapted to the process very well, it brings great convenience. The cutting tool according to claim 16 or 18.
Protects the blade from abrasion when used in the above shears.
In addition to causing distortion or steps on the cut surface of the steel bar.
With a screw that can eliminate the occurrence of burrs on the cut surface
Can it to provide a cutting tool for bar steel cutting. Claim 1
According to the cutting tool described in No. 9, a threaded steel bar cutting shear
Allows compatibility between shears and shears for drilling steel
A cutting tool for the shears can be provided.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a shearing machine according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a front end portion of the shears shown in FIG.

3 is a plan view showing a front end portion of the shears shown in FIG. 1. FIG.

4 is a side view showing a front end portion of the shears shown in FIG. 1. FIG.

FIG. 5 is an elevational view of a fixed blade.

FIG. 6 is a partially enlarged cross-sectional view of a screw formed in the concave portion of the fixed blade.

FIG. 7 is a perspective view showing a second embodiment of the present invention.

FIG. 8 is a side view of the embodiment shown in FIG.

FIG. 9 is a plan view around a fixed blade and a movable blade of a shearing machine according to a third embodiment of the present invention.

FIG. 10 is a vertical cross-sectional view around a fixed blade and a movable blade of the shears shown in FIG.

11 is an elevational view of the fixed blade shown in FIGS. 9 and 10. FIG.

12 is a partially enlarged elevational view showing a structure around a female screw and a slit of the fixed blade shown in FIGS. 9 to 11. FIG.

13 is a partially enlarged cross-sectional view showing a structure around a female screw and a slit of the fixed blade shown in FIGS. 9 to 12. FIG.

FIG. 14 is a partial enlarged cross-sectional view showing the structure around the female screw and the slit of the fixed blade shown in FIGS. 9 to 12.

[Explanation of symbols]

 1 Shearing Machine 6 Jaw 7 Fixed Blade 10 Movable Blade 10a Dimple 11 Cutting Edge Part 12 Base 13 Fixing Screw 58 Piston Rod 71 Fixed Blade Part 72 Slit 73 Female Thread 74 Base 75 Fixing Screw W Steel Bar

Claims (19)

[Claims] 1. A movable blade attached to a front end portion of a piston rod, and a fixed blade attached to a main body, wherein the fixed blade has a shape substantially complementary to an outer shape of a threaded steel bar to be cut. A shearing machine having a recessed portion having a female thread corresponding to the male thread of the steel bar, wherein the movable blade has a cutting edge portion whose front end is pressed against the steel bar when the movable blade is advanced. And the fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, the slit is opposed to the cutting blade portion, and the cutting blade portion is advanced. In this case, the fixed blade portion is positioned to accommodate the cutting blade portion, the fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions. , cutting the rod steel, the central axis of the recess, the width axis of the fixed blade For
A shearing machine characterized by being inclined at a predetermined angle . 2. A movable blade attached to the front end portion of the piston rod, and a fixed blade attached to the main body, the fixed blade having a shape substantially complementary to the outer shape of the threaded steel bar to be cut. A shearing machine having a recessed portion having a female thread corresponding to the male thread of the steel bar, wherein the movable blade has a cutting edge portion whose front end is pressed against the steel bar when the movable blade is advanced. And the fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, the slit is opposed to the cutting blade portion, and the cutting blade portion is advanced. In this case, the fixed blade portion is positioned to accommodate the cutting blade portion, the fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions. , cutting the rod steel, internal thread of the recess, the flat apexes of thread Made
The side wall defining the slit is located at the top of the thread.
A shearing machine characterized by being placed . 3. A movable blade attached to the front end portion of the piston rod and a fixed blade attached to the main body, the fixed blade having a shape substantially complementary to the outer shape of the threaded steel bar to be cut. A shearing machine having a recessed portion having a female thread corresponding to the male thread of the steel bar, wherein the movable blade has a cutting edge portion whose front end is pressed against the steel bar when the movable blade is advanced. And the fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, the slit is opposed to the cutting blade portion, and the cutting blade portion is advanced. In this case, the fixed blade portion is positioned to accommodate the cutting blade portion, the fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions. , cutting the rod steel, the slits relative to the fixed blade, the recess Female thread
Tilted at an angle set to be almost the same as the lead angle of
The screw thread near the side wall of the slit is generally called a slit.
Extends in parallel between the exposed end surface of the fixed blade and the bottom of the recess
A shearing machine, characterized in that the portions of the side walls located at the positions extend substantially parallel to each other . 4. A movable blade attached to the front end portion of the piston rod, and a fixed blade attached to the main body, the fixed blade having a shape substantially complementary to the outer shape of the threaded steel bar to be cut. A shearing machine having a recessed portion having a female thread corresponding to the male thread of the steel bar, wherein the movable blade has a cutting edge portion whose front end is pressed against the steel bar when the movable blade is advanced. And the fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, the slit is opposed to the cutting blade portion, and the cutting blade portion is advanced. In this case, the fixed blade portion is positioned to accommodate the cutting blade portion, the fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions. , cutting the rod steel, fixed blade support shear machine body for supporting the fixed blade To the minute
Is formed with a broken material passage, and the broken material passage is formed in the slit.
And the slit is adjacent to the exposed end surface of the fixed blade.
The left and right first side walls, and the first side wall and the broken material passage
The second side walls are disposed between the left and right second side walls, and the distance between the second side walls is equal to the distance between the first side walls.
A shearing machine characterized by being larger than the distance of . 5. A movable blade attached to the front end portion of the piston rod and a fixed blade attached to the main body, the fixed blade having a shape substantially complementary to the outer shape of the threaded steel bar to be cut. A shearing machine having a recessed portion having a female thread corresponding to the male thread of the steel bar, wherein the movable blade has a cutting edge portion whose front end is pressed against the steel bar when the movable blade is advanced. And the fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, the slit is opposed to the cutting blade portion, and the cutting blade portion is advanced. In this case, the fixed blade portion is positioned to accommodate the cutting blade portion, the fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions. , cutting the rod steel, the fixed blade, the Yabuzai disposed shearing machine body And the hole
A hollow portion that communicates with the bottom of the slit;
And a side wall that communicates with the section and defines the slit.
And the side wall expands toward the hollow.
A shearing machine characterized by forming a broken material discharge path . 6. A movable blade attached to a front end portion of a piston rod and a fixed blade attached to a main body, the fixed blade having a shape substantially complementary to an outer shape of a threaded steel bar to be cut. A shearing machine having a recessed portion having a female thread corresponding to the male thread of the steel bar, wherein the movable blade has a cutting edge portion whose front end is pressed against the steel bar when the movable blade is advanced. And the fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, the slit is opposed to the cutting blade portion, and the cutting blade portion is advanced. In this case, the fixed blade portion is positioned to accommodate the cutting blade portion, the fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions. , cutting the rod steel, the base of the fixed blade, the formation of generally cylindrical , The base
The end face of the part is a shoulder part formed in the breakage hole of the shearing machine body
Abutting against, and acting on the fixed blade during shearing work
Load on the reaction force generated on the end faces of the shoulder and the base.
Therefore , a shearing machine characterized by being supported . 7. A movable blade attached to the front end portion of the piston rod and a fixed blade attached to the main body, the fixed blade having a shape substantially complementary to the outer shape of the threaded steel bar to be cut. A shearing machine having a recessed portion having a female thread corresponding to the male thread of the steel bar, wherein the movable blade has a cutting edge portion whose front end is pressed against the steel bar when the movable blade is advanced. And the fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, the slit is opposed to the cutting blade portion, and the cutting blade portion is advanced. In this case, the fixed blade portion is positioned to accommodate the cutting blade portion, the fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions. , cutting the rod steel, the central axis of the recess, the center line of the slit Against
The slit is inclined at a predetermined angle with respect to the perpendicular
The angle between the center line of the groove and the center axis of the recess is 90 degrees.
Smaller than the slit, the slit is
Oriented so as to form a cutting plane in the angle direction of the steel bar.
Shears, characterized in that that. 8. The cutting edge portion abuts on the outer circumference of the steel bar.
Has an arcuate depression with an inner peripheral surface
Are opposed to the depressions.
The shearing machine according to any one of 7 above. 9. The method of claim 8, female thread corresponding to the external thread of the steel bar is being formed in the recess of the movable blade
The shearing machine described in. 10. internal thread of the recess, the apex of the screw thread is formed flat, the side walls defining said slit claim 1 or請, characterized in that located at the top of the screw thread
The shearing machine according to any one of claims 3 to 9. 11. The distance between a center line of the thread adjacent to the sidewall defining the slit and the sidewall is 0 to 0.3.
claim characterized in that it is set to a value in the range of mm 1
The shearing machine according to any one of 1 to 10. 12. The shearing machine according to claim 5 , wherein a curved portion having a small diameter is provided at an intersection of the side wall and the bottom wall of the slit. 13. The clearance between the width of the slit and the cutting edge portion of the fixed blade is set to 0.3 to 0.8 mm, according to any one of claims 1 to 12.
The shearing machine according to the item. 14. The shearing machine according to claim 7, wherein the predetermined angle formed by the central axis of the recess and the perpendicular of the slit is set to 3 to 5 degrees . 15. The movable blade and the fixed blade are provided with a base that is compatible with a punch and a die for punching a steel material. Shears. 16. A recess having a movable blade attached to the front end portion of the piston rod and a fixed blade attached to the main body, the fixed blade having a shape substantially complementary to the outer shape of the threaded steel bar to be cut. In the cutting tool of the shearing machine, wherein the recess has a female thread corresponding to the male thread of the steel bar, the movable blade has a cutting edge portion that is pressed by the steel bar when the movable blade advances. The fixed blade has left and right fixed blade portions and a slit arranged between the fixed blade portions, and the slit extends in the direction of the lead angle of the female screw of the recess to define the slit. The side wall is located at or near the top of the thread of the internal thread of the recess, and the slit is configured to accommodate the cutting edge portion of the movable blade when the movable blade advances. With a width that can receive the blade part, The fixed blade portion supports the steel bar on both sides of the movable blade, and the movable blade presses the steel bar between the left and right fixed blade portions to cut the steel bar. A cutting tool for a shearing machine. 17. The cutting edge portion has an arcuate recess having an inner peripheral surface that abuts the outer periphery of the steel bar, and the radius of curvature of the inner peripheral surface is set to be larger than the radius of the steel bar. The cutting tool for a shearing machine according to claim 16, wherein: 18. The cutting tool for a shearing machine according to claim 16, wherein the slit extends substantially parallel to the lead angle direction of the female screw of the recess. 19. The movable blade and the fixed blade each have a base portion compatible with a punch and a die for punching a steel material, respectively. Shears cutting tools.