JP5863573B2 - H-section steel cutting method, control device, and horizontal band saw with horizontal band saw - Google Patents

Description

  The present invention relates to a cutting method, a control device, and a horizontal band saw for efficiently cutting H-shaped steel with a horizontal band saw without causing narrowing of the saw blade.

  In the cutting process in which H-shaped steel, especially wide and long H-shaped steel, which is often used in construction, is cut into steel materials of a predetermined length using a band saw or a circular saw, the saw blade is the cutting surface of the shaped steel. “Saw blade constriction” is likely to occur. If the saw blade is narrowed, the saw blade is prevented from traveling and cutting is impossible, so there is a strong demand for its avoidance.

Saw blade stenosis occurs as follows. That is, the H-shaped steel generates a strong internal stress due to the pressure applied by the rolling roller in the manufacturing process. When the groove 22 is formed by cutting with a saw blade as shown in FIG. 8A, the internal stress particularly expands the cutting surface of the web 20b as a stress releasing action. Due to the expansion of the cutting surface, the width of the kerf 22 is narrowed, and the body of the saw blade 21 is sandwiched in the kerf 22. This is the saw blade stenosis.

  In order to avoid the narrowing of the saw blade, the saw blade 21 is generally punched out on both the left and right sides to make the groove 22 wider than the saw thickness, as shown in FIGS. "Clam" has been formed. In the clam, the center blade C and the left and right blades L and R are alternately arranged in the longitudinal direction of the saw blade 21. Thereby, if the cutting surface is somewhat expanded, the saw blade is not narrowed.

As a typical material in which saw blade narrowing easily occurs, there is an H-shaped steel 20 for construction as shown in FIG. The H-beam for construction tends to increase the width of the web 20b in order to increase the load capacity. In cutting such a wide H-shaped steel, but does not occur stenosis in cutting the upper portion and the right portion of the web 20b of the flange 20a, cutting the web 20b at remaining state is uncut portion in the lower portion of the flange 20a Then, the expansion of the cutting surface increases as the center of the web 20b having a high compression internal stress is approached. When the expansion amount is greater than the clearance, the saw blade 21 cannot run due to the body portion being sandwiched between the cutting surfaces, and the saw blade 21 becomes unable to cut.

  Various measures have been proposed in the past to prevent saw blade stenosis. For example, in the technique described in Patent Document 1 (Japanese Patent Laid-Open No. 10-43936), when the narrowing is likely to occur, the saw blade is stopped by stopping the cutting of the saw blade, raising the saw blade by a predetermined amount, and cutting again. This is a method of avoiding stenosis. Whether the saw blade stenosis is likely to occur is determined by detecting an increase in the current of the motor that drives the drive wheel of the saw blade.

  Further, the technique described in Patent Document 2 (Japanese Patent Laid-Open No. 9-70713) is an H-section steel cutting machine having three independent circular saws, and includes right and left flanges and a central web of the H-section steel. Cutting is performed by cooperative control so that the circular saws do not interfere with each other and narrowing does not occur.

JP-A-10-43936 JP-A-9-70713

  In the technique of Patent Document 1, the cutting position where the saw blade stenosis is likely to occur and the current value of the saw wheel drive motor when cutting the cutting position are set and stored in advance, and the stored value and the actual cutting of the saw blade are stored. The position and the current value of the drive motor are compared and determined. If it is determined that the narrowing is likely to occur, the cutting of the saw blade is stopped, the saw blade is raised by a predetermined amount, and then the cut groove is cut and widened by cutting again to avoid the narrowing of the saw blade. The technique of this patent document 1 does not fundamentally solve the saw blade constriction, and the saw blade constriction is avoided by repeated useless movement of the saw blade, so that the cutting efficiency naturally decreases. In addition, since the current value is unstable, the current value is narrowed by erroneous detection, and the saw blade is often damaged.

On the other hand, since the technique of Patent Document 2 uses a plurality of circular saws, it is possible to prevent saw blade constriction depending on the cutting order, but since three circular saws are simultaneously moved along one cutting surface, The mechanical structure and its control are complicated, and there is a problem that the price of a consumable blade is high.
From the above, the current situation is that a radical solution to the saw blade narrowing has not yet been made.

  The present invention relates to a cutting method, a control device, and a horizontal band saw for efficiently cutting H-shaped steel with a horizontal band saw without causing narrowing of the saw blade.

The means for solving the above-described problems according to the present invention will be described below.
As is well known, the H-section steel 20 shown schematically in FIG. 1 is a steel material having a shape in which a pair of left and right flanges 20a are integrated with an intermediate web 20b. The H-shaped steel 20 is manufactured by sequentially rolling an ingot of a primary material shape with a plurality of stages of rolling rolls. At this time, a strong internal stress is generated in the H-section steel 20 by rolling.

FIG. 2 shows the internal stress distribution of the H-section steel. As can be seen from the figure, the internal stress may be 200 N / mm ² or more in the vicinity of each central portion of the web 20b and the flange 20a, and both the web 20b and the flange 20a are high in the central portion and decrease as they go to both sides. Become. As for each internal stress, the web 20b is a compressive stress, and the flange 20a is a tensile stress. Generally, when the compression internal stress becomes 200 N / mm ² or more, it is considered that saw blade narrowing occurs. In the case of a wide H-shaped steel, the saw blade narrowing occurs in a section of about 1/3 of the center of the web 20b. . Since the flange 20a has a tensile stress, the saw blade is not constricted.

As shown in FIG. 9, in the conventional horizontal band saw machine for cutting the H-shaped steel 20, the saw blade 21 has a constant inclination angle θ of about 6 to 10 degrees with respect to the horizontal. The saw frame 7 is moved up and down while maintaining this constant inclination angle θ. The reason why the saw blade 21 is set to be “a constant inclination angle θ” without being close to the horizontal or horizontal is that when the saw blade 21 is close to the horizontal, the cutting length of the saw blade 21 when cutting the flange 20a (parts involved in cutting). This is because the difference in length between the saw blade 21 and the cutting length of the saw blade 21 when cutting the web 20b becomes too large, so that cutting is difficult and cutting efficiency is poor.

  As described above, the “constant inclination angle θ” of 6 to 10 degrees is a device for leveling the cutting length as much as possible. Although it is desirable that the inclination angle θ is large, the height h of the bed 3 cannot be so high in terms of workability and versatility. That is, if the inclination angle θ is too large, the right end portion of the saw frame 20 is held on the ground in FIG. 9 before the cutting is completed. For this reason, the inclination angle θ is suppressed to about 10 degrees.

Here, as shown in FIG. 3, for example, when the H-section steel 20 is cut using a horizontal band saw machine in which the inclination angle θ of the saw blade 21 is constant at about 10 degrees, the body portion of the saw blade 21 is Saw blade narrowing does not occur in the low internal stress section (W / 3 on the right side) before reaching the vicinity of the center of the web 20b. However, the saw blade narrowing occurs when the body of the saw blade 21 advances to the high internal stress section, that is, the vicinity of the center where the internal stress is 200 N / mm ² or more (W / 3 in the center) (see FIG. 3). The position of the two-dot chain line).

As described above, the present invention has been made paying attention to the fact that the saw blade narrowing does not occur in the low internal stress section outside the vicinity of the central portion of the web 20b, and the principle thereof will be described below.
1. The cutting of the web 20b completely cuts one of the flanges on the cutting start side to the bottom during the cutting of the low internal stress section before the high internal stress section near the center, that is, the low internal stress section where the saw blade is not narrowed.
2. Then, due to the internal stress releasing action of the web 20b, the kerf 22 is expanded as shown in FIG. 8B, whereby the high internal stress near the center of the web 20b is released.
3. Thereafter, cutting is performed in a state where the kerf 22 is expanded , that is, in a state where there is no fear of the saw blade narrowing, and the cutting is completed.
That's it.

The following shows how to apply this principle to an actual horizontal band saw.
As shown in FIG. 4B, one side of the saw frame 7 is largely lifted to give the saw blade 21 a steep inclination (for example, 20 ° to 30 °), and in this state, the flange on one side is first completely cut to the lower end. In this process, the web is also partially cut, but the saw blade narrowing does not occur because of the low internal stress section. When the flange on one side is completely cut down to the bottom, the internal stress of the web trying to sandwich the body portion of the saw blade 21 is released, and the groove width of the kerf 22 is changed from b to c as shown in FIG. To spread. Therefore, the remaining web 20b and the flange 20a are cut while returning the saw frame 7 to a gentle inclination (for example, 10 ° to 5 °). In this process, since the internal stress of the web 20b is released, the cutting is completed without causing the saw blade narrowing.

  By adopting the above method, unlike the conventional method, the H-section steel can be cut very efficiently while reliably avoiding the narrowing of the saw blade. Further, since the cutting length of the saw blade with respect to the H-shaped steel section is further leveled, the cutting efficiency of the saw blade is further increased, and the heat generation of the saw blade tip is reduced, so that the life of the saw blade is greatly extended.

It is a perspective view of H section steel under cutting. It is sectional drawing of the H-section steel which attached | subjected the measured value of internal stress distribution. It is sectional drawing of the H-section steel at the time of cutting by a horizontal type band saw. 1 is a schematic perspective view of a horizontal band saw machine according to the present invention. It is a front view of the horizontal type band saw machine concerning the present invention. It is sectional drawing of H-section steel which shows the cutting process by the horizontal type band saw machine concerning this invention in order. It is a flowchart which shows the cutting method by the horizontal band saw machine which concerns on this invention. (A) is a side view of a saw blade, (B) is a bottom view of the blade edge of the saw blade, and (C) is a cross-sectional view taken along line XX of the saw blade of (A). (A) (B) is a top view which shows a kerf when a saw blade is removed in the cutting process of H-section steel, (A) is when the right flange has not been cut to the bottom, (B) Indicates when the right flange has been cut to the bottom. Conventional, is a front view of a lateral band saw machine having a constant inclination angle degree.

  Embodiments of a horizontal band saw machine, a cutting method using the horizontal band saw machine, and a control device according to the present invention will be described below with reference to the drawings.

  As shown in FIGS. 4A and 4B, a horizontal bed 3 is provided on the base 2 of the horizontal band saw 1 for placing an H-shaped steel 20 as a work material. A fixed vise jaw 4 and a movable vise jaw 5 are disposed to clamp them from the left and right directions.

  Further, two guide pillars 14 and 15 constituting a gate shape are arranged on the left and right on the base 2, and linear rails 14 a and 15 a are provided along the inner side surfaces of the respective guide pillars 14 and 15. . A left elevating plate 16 and a right elevating plate 17 are engaged with the linear rails 14a and 15a via linear blocks (not shown), and these elevating plates 16 and 17 are erected along the guide columns 14 and 15, respectively. Are supported at the tips of rods 18a, 19a of left and right hydraulic cylinders 18, 19 as lifting actuators.

In front of the right elevator plate 17 right fulcrum shaft 17a is implanted perpendicular to the drawing, in the right fulcrum shaft 17a, by the metal 17b is fitted, which is provided in the right lower part of the horizontal saw frame 7 The saw frame 7 is supported so as to be swingable in the vertical direction.

On the other hand, a linear rail 7a is provided substantially in the left-right direction on the left rear surface of the saw frame 7, and a saw frame support plate 16a is engaged with the linear rail 7a via a linear block (not shown). Left supporting point shaft 16b is the rear surface of the saw frame support plate 16a is implanted perpendicular to the drawing, the left supporting point shaft 16b is fitted to the left elevator plate 16. Thus, the left portion of the saw frame 7 is supported so as to be swingable in the vertical direction, and the saw frame 7 is prevented from swinging back and forth.

  A drive saw wheel 10 is disposed on the right side of the saw frame 7, and a driven saw wheel 11 is disposed on the left side. Then, an endless saw blade (band saw) 21 is wound around these two saw wheels 10 and 11, and a drive motor (not shown) connected to the rotating shaft of the drive saw wheel 10 is driven in the direction of the arrow in FIG. 4B. The saw blade 21 travels.

  A fixed saw guide 12 is disposed on the right side of the saw frame 7 above the fixed vise jaw 4. In addition, a movable saw guide 13 extending downward is provided at a position above the movable vise jaw 5 of the saw frame 7 so as to be movable along a rail 7b provided in the left-right direction at the lower center of the saw frame 7. Yes. The saw blade 21 is supported by the two fixed and movable saw guides 12 and 13 so that the saw blade 21 can run freely with its blade edge facing downward.

  The horizontal band saw machine 1 of the present invention is configured as described above. A method for cutting H-section steel using the horizontal band saw machine 1 will be described in order with reference to FIGS.

Prior to cutting, as shown in FIG. 4B, the H-shaped steel 20 is sandwiched and fixed between the vice jaws 4 and 5 on the bed 3 from the left and right sides, and the H-shaped steel as shown in FIGS. 5 (A) → (B). The upper half of 20 right flanges 20a is cut. At this time, the left lifting plate 16 is kept at a fixed height, and only the right lifting plate 17 is lowered. That is, the saw frame 7 provided with a saw blade 21 descends while the swing movement around the left supporting point shaft 16b to be fitted to the left elevator plate 16, to cut the top half of the right flange 20a (first step ).

Following the cutting of the upper half of the right flange 20a, the cutting of the lower half of the right flange 20a and the right part of the web 20b is started, as shown in FIGS. Also at this time, only the right lifting plate 17 is lowered while the left lifting plate 16 is kept at a constant height. As a result, the inclination angle of the saw blade 21 immediately before the completion of the cutting of the right flange 20a becomes extremely large, and the right portion of the web 20b that has been cut up to that time is in the low internal stress section, so that the saw blade narrowing does not occur ( Second process).

The right flange 20a is completely cut to the bottom as shown in FIG. 5C, and at the same time, the internal stress of the web 20b is released, and the groove width of the cut groove 22 is widened as shown by the arrow in FIG. 8B. From that point on, the saw frame 7 is returned to a gentle inclination to cut the remaining web 20b and the left flange 20a without fear of constricting the saw blade. At this time , the right lifting plate 17 is stopped and only the left lifting plate 16 is lowered. The saw frame 7 provided with the saw blade 21 is lowered as shown in FIGS. 5D, 5E, and 5F while swinging around a right fulcrum shaft 17a planted on the front surface of the right lifting plate 17. Then, the cutting of the H-section steel 20 is completed (third process).

The cutting process shown in FIG. 5 is executed in detail by steps S1 to S16 in the flowchart of FIG. This flowchart is stored in the form of a computer program in the control device 25 of the horizontal band saw 1 of FIG. 4A. First, in step S1, the material, shape and dimensions of the H-section steel as a workpiece are the horizontal type of FIG. 4A. It is input to the control device 25 of the band saw machine 1. The controller 25, based on pre-material of the H-shaped steel, shape, the control parameters are stored, the input information of the hydraulic cylinders 18, 19 and drive a saw wheel 10 of the right or left in correlation with the size step In S2, optimum cutting conditions are searched.

Next, after the cutting length of the saw blade 21 corresponding to the position of the saw blade tip changing in step S3 is calculated, the right swing motion of the saw frame 7 is started in step S4, and the right hydraulic cylinder 19 is lowered in step S5. The (shortening) control is started. In step S6, the position of the cutting edge of the saw blade 21 is detected. In step S7, the cutting of the right flange 20a is started, the upper half of the right flange 20a is cut (first process), and the lower half of the right flange 20a is continuously cut. Cutting of the web 20b is applied.

  In step S8, it is determined whether or not the cutting of the right flange 20a is completed. If it is determined that the cutting is completed, the lowering control of the right hydraulic cylinder 19 is stopped in step S9 (second process). Then, the left swing movement of the saw frame 7 is started in step S10, and the lowering (shortening) control of the left hydraulic cylinder 18 is started in step S11.

Next, in step S12, the cutting edge position of the saw blade 21 is detected, and in step S13, the web 20b is continuously cut, and the left flange 20a is cut in the middle. In step S14, it is determined whether or not the cutting of the left flange 20a has been completed. If it is determined that "cutting is complete", the lowering control of the left hydraulic cylinder 18 is stopped in step S15 (third process), and the left and right in step S16. The return operation of the hydraulic cylinders 18 and 19 to their original positions is performed.

In the conventional cutting method, generally, the angle of inclination of the saw blade 21 is a constant angle of 10 degrees or less from the beginning to the end, or one end of the saw frame 7 is supported by a hinge shaft and the saw blade 21 is swung by a swing motion. However, in any method, the body of the saw blade 21 reaches the vicinity of the center of the web 20b before the cutting of the H-shaped steel one-side flange 20a is completed. . Also, at an inclination angle of 10 degrees or less, the cutting efficiency of the flange 20a is short and the cutting length of the web 20b is long, so that the cutting efficiency is not good.

According to the present invention, the inclination angle of the saw blade 21 can be made sufficiently large, so that the cutting of the flange 20a is completed before the body portion of the saw blade 21 reaches the vicinity of the central portion where the internal stress of the web 20b is large. Saw blade stenosis can be completely avoided. Further, by increasing the inclination angle of the saw blade 21, reduce the cutting length of the web 20b extended cutting length of the flange 20a, that is, since every case of leveling Cutting length is increased to improve the cutting efficiency, the saw The life of the blade 21 is also extended.

  The inclination angle (maximum inclination angle) of the saw blade 21 when the right flange 20a has been cut is desirably increased to 30 degrees or more, but the number of times is appropriately changed according to the size of the H-section steel. can do.

  As described above, when the right flange 20a is cut, the right elevating plate 17 is stopped, and the left elevating plate 16 is lowered to swing the saw frame 7 to perform the remaining cutting. The height stays the same as before. This ensures workability and versatility.

In the present embodiment, in the process of cutting the right flange 20a, the lowering of the left part of the saw frame 7 is stopped and the "swing motion" is performed to lower the right part. It is self-evident that “a constant inclination angle movement ” in which the saw frame 7 is lowered while maintaining the same angle as that at the time of completion of the cutting 20a.

Further, in the present embodiment uses a hydraulic cylinder as an actuator for elevating the left and right elevating plates 16 and 17 is not limited to hydraulic cylinders, etc. ball screw, the elevating plate 16, 17 in a vertically movable actuator Of course, there is nothing to do.

  Here, the terms in the above sentence are explained. The “central portion” of the web 20b corresponds to a division point that is a half of the entire width of the web 20b, but also includes a portion that extends to some extent on both sides of the half division point. This is the W / 3 section in the center of FIG. This central W / 3 section has a high internal compressive stress and is a portion where saw blade narrowing is likely to occur.

  Since the horizontal band saw of the present invention is a cutting method that fundamentally eliminates the possibility of saw blade narrowing as described above, it is possible to increase the cutting speed to about twice that of the prior art. Further, according to this method, since the cutting action length of the saw blade tip with respect to the H-shaped steel section is leveled by giving a sharp inclination to the saw blade, the cutting efficiency of the saw blade is further increased and the saw blade tip is further improved. Heat generation is suppressed and the life of the saw blade is extended.

1: Horizontal band saw 7: Saw frame 16: Left lifting plate 17: Right lifting plate 20: H-shaped steel 21: Saw blade 25: Control device

Claims (5)

In a cutting method in which a H-shaped steel in which a pair of left and right flanges are integrated by an intermediate web is cut in a transverse direction by a saw blade of a horizontal band saw machine,
A first step of cutting the upper half of one flange with the saw blade tilted by lifting one side of the saw frame of the band saw machine;
A second process in which the saw blade simultaneously cuts the lower half of the one flange and the web, and completes the cutting of the one flange by the time the saw blade reaches the center of the web; and the web A third process of cutting the remaining part of and the other flange;
Cutting method of H-section steel by horizontal band saw machine having   The flange cutting in the first and second processes is advanced by increasing the inclination angle of the saw blade or by lowering the saw blade while maintaining the inclination angle of the saw blade. Cutting method.   2. The cutting method according to claim 1, wherein after the cutting of the one flange is completed in the second process, the third process is performed while bringing the inclination angle of the saw blade close to the horizontal. A control device for a horizontal band saw for executing the cutting method according to any one of claims 1 to 3. A horizontal band saw machine comprising the control device according to claim 4.

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