Angle bar inward bending device

Abstract

To provide an inward bending device for angle bars, which can improve bending accuracy by preventing unexpected deformation due to stress applied during bending between nips of rollers while eliminating the need for complex control of each roller. [Solution] The premise is an inner bending device X that inwardly bends an angle bar L into a highly circular body by passing it through a nip between upstream and downstream rollers 12, 13 that face a top roller 11 driven in a forward rotation direction and drive in reverse rotation directions. A gap is provided between the upper and lower large-diameter and small-diameter rollers of the top roller 11 to fit a horizontal piece of the angle bar L. Meanwhile, when inwardly bending the angle bar L along the circumferential surface of the top roller 11, the upper small-diameter roller presses the vertical piece of the angle bar L from the outside toward the tapered surface of the lower small-diameter roller of the top roller 11, with the lower end of the vertical piece abutting against the upper edge of the lower large-diameter roller.

Description

[Technical Field]

[0001] The present invention involves inward bending an angle bar having an L-shaped cross section into a circular body with high circularity. Inner bending device Regarding. [Background technology]

[0002] Conventionally, angle bars with an L-shaped cross section are bent inward. Inner bending device One known example of such a method is to pass an L-shaped cross-section angle bar, which is fed in a strip shape from the tip, through a nip between one of three rollers, a top roller, and two bottom rollers, which face each other in order from the upstream side in the feeding direction of the angle bar, to perform an inward bending process (see Patent Document 1).

[0003] Also, Inner bending device is provided with a pressure roller disposed between the two bottom rollers facing the top roller, and which presses the angle bar passing through the top roller. This pressure roller and the three rollers are supported on the base plate so as to be rotatable about axes extending in the vertical direction.

[0004] Furthermore, the top roller is supported so as to be rotatable about its axis, while the two bottom rollers and pressure roller are supported so as to be movable toward and away from the top roller, and by moving each of the bottom rollers and pressure rollers toward and away from the top roller, the angle bar passing through the nip between each of the bottom rollers and pressure rollers is bent inward to form a highly circular body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-66644 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional bending device, when bending an angle bar to form a circular body with high circularity, it is necessary to move each roller back and forth in accordance with the angle bar passing through the nip between the top roller and two bottom rollers and the pressure roller, which makes the control of the movement of each roller very complicated.

[0007] Furthermore, when the angle bar passes between the nips of the top roller and each roller, both ends of the angle bar, i.e., the open ends of the horizontal and vertical pieces, are open and do not come into contact with either roller, so there is a risk that the angle bar may be accidentally deformed by the stress applied during bending between the nips of the rollers, which poses a risk to the accuracy of bending the angle bar.

[0008] The present invention has been made in view of the above points, and its object is to provide an angle bar that can improve bending accuracy by preventing accidental deformation due to stress applied during bending between the nip between rollers while eliminating the need for complex control of each roller. Inner bending device The purpose is to provide [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the present invention is based on an inner bending device that passes an angle bar with an L-shaped cross section, which is fed in a strip-like shape, through a nip between one of three rollers and the remaining two rollers that face each other in order from the upstream side in the feeding direction of the angle bar, to inner bend the angle bar into a circular body with high circularity. Furthermore, the three rollers include a top roller that is driven in a forward rotation direction around an axis extending in the vertical direction on the substrate, an upstream bottom roller that is driven in a reverse rotation direction around an axis extending in the vertical direction on the upstream side of the substrate in the feed direction of the angle iron, and bends the fed angle iron inward along the circumferential surface of the Top roller between the nip with the Top roller, and a downstream bottom roller that is driven in a reverse rotation direction around an axis extending in the vertical direction on the downstream side of the upstream bottom roller on the substrate in the feed direction of the angle iron, and bends the angle iron that has been bent inward between the nip between the upstream bottom roller and the top roller, further inward along the circumferential surface of the Top roller between the nip with the Top roller.

[0010] The top roller has upper and lower large-diameter and small-diameter rollers with different diameters, and a gap is formed between the large-diameter and small-diameter rollers into which the substantially horizontal horizontal piece of the angle bar is inserted. On the other hand, the upstream and downstream bottom rollers have upper and lower small-diameter and large-diameter rollers with different diameters, and when the angle bar is bent inward along the circumferential surface of the top roller, the substantially vertical vertical piece of the angle bar is pressed from the outside by the upper small-diameter roller toward the lower small-diameter roller of the top roller with its lower end abutting the upper edge of the lower large-diameter roller. pressure are.

[0011] In addition, The outer peripheral surface of the small diameter roller of the top roller is formed into a tapered surface that is inclined so that the diameter increases as it goes downward. It is characterized by:

[0012] It is also preferable to provide a straightening roller that rotates about an axis extending vertically downstream of the downstream bottom roller on the substrate in the angle iron feed direction, and that straightens the angle iron, which has been bent further inward between the nip between the top roller and the downstream bottom roller, by pressing outward on the inner end of the horizontal piece or the inner side of the vertical piece of the angle iron, so that the angle iron becomes approximately circular.

[0013] It is also preferable to have an upstream auxiliary roller that rotates about an axis extending vertically upstream of the upstream bottom roller on the base plate in the direction of feeding of the angle iron, and guides the inner end of the horizontal piece or the inside of the vertical piece of the fed-out angle iron, and an upstream attachment roller that rotates about an axis extending vertically immediately upstream of the upstream bottom roller on the base plate in the direction of feeding of the angle iron, and presses the vertical piece of the angle iron, the inner end of which is guided by the upstream auxiliary roller, against the upstream bottom roller by abutting it from the inside.

[0014] It is also preferable to provide a downstream attachment roller that rotates about an axis extending in the vertical direction immediately downstream of the top roller on the substrate in the direction of feeding of the angle iron, and presses the vertical piece of the angle iron from the inside outward while maintaining the horizontality of the horizontal piece that is bent further inward between the nip between the upstream bottom roller and the top roller.

[0015] It is preferable to provide a downstream auxiliary roller that rotates about an axis extending in the vertical direction downstream of the top roller on the base plate in the direction of feeding of the angle iron, and that guides the angle iron, whose center point moves downstream when the end of the angle iron reaches the nip between the top roller and the downstream bottom roller, by abutting against its vertical part.

[0016] Furthermore, an upstream guide roller is provided laterally between the upstream auxiliary roller and the upstream attachment roller on the base plate, for guiding the angle bar substantially horizontally in the feed direction by contacting the lower end of its vertical piece between the two rollers, and a downstream guide roller is provided laterally between the downstream auxiliary roller and the downstream attachment roller, for guiding the angle bar in the feed direction by contacting the lower end of its vertical piece between the two rollers. It is preferable that the rotation axes of the upstream and downstream guide rollers are each substantially perpendicular to the feed direction of the angle bar, which is guided substantially horizontally by the two guide rollers.

[0017] It is also preferable that the correction roller, the downstream auxiliary roller and the downstream guide roller are supported on a downstream rotating table that rotates around an axis extending in the vertical direction near the downstream guide roller on the base plate, and that when the angle bar is bent inward, the angle bar is rotated around the axis of the downstream rotating table depending on the diameter of the angle bar.

[0018] Furthermore, it is preferable that the upstream auxiliary roller and the upstream guide roller are supported on an upstream rotating table that rotates around an axis extending vertically near the upstream guide roller on the base plate, and that when the angle bar is bent inward, the angle bar is rotated around the axis of the upstream rotating table in accordance with the diameter of the angle bar. [Effects of the Invention]

[0019] In summary, when bending an angle bar inward along the circumferential surface of the top roller, the horizontal piece of the angle bar is inserted into the gap between the upper and lower large-diameter and small-diameter rollers of the top roller, while the vertical piece of the angle bar is pressed from the outside toward the lower small-diameter roller of the top roller by the upper small-diameter roller, with its lower end abutting the upper edge of the lower large-diameter roller of each bottom roller. Therefore, when bending the angle bar inward, the horizontal piece of the angle bar is inserted into the gap between the large-diameter and small-diameter rollers of the top roller, and the lower end of the vertical piece, which is pressed from the outside toward the lower small-diameter roller of the top roller by the upper small-diameter roller, abuts the upper edge of the lower large-diameter roller of each bottom roller. This eliminates the need to move the bottom rollers back and forth when bending the angle bar to form a highly circular body, thereby eliminating the need for complex control of the bottom rollers.

[0020] Furthermore, when the angle bar passes through the nip between the top roller and each bottom roller, the horizontal piece of the angle bar is inserted into the gap between the large-diameter and small-diameter rollers of the top roller, restraining it from above and below, and the lower end of the vertical piece is abutted against the upper edge of the large-diameter roller of each bottom roller and restrained, thereby preventing accidental deformation due to stress applied during bending between the nip between the rollers and improving the bending accuracy of the angle bar.

[0021] In addition, by forming the outer surface of the small-diameter roller of the top roller into a tapered surface that slopes so that the diameter increases as it goes downward, it is possible to suppress deformation in which the vertical piece bends to a narrow angle of less than 90° relative to the horizontal piece due to the stress acting when inwardly bending an angle bar with an L-shaped cross section, thereby further improving the bending accuracy of the angle bar.

[0022] Furthermore, by using a straightening roller located downstream of the downstream bottom roller on the substrate in the angle bar feeding direction, the inner end of the horizontal piece or the inner side of the vertical piece of the angle bar that has been bent further inward between the top roller and the downstream bottom roller is pressed outward, thereby expanding the diameter of the angle bar and straightening it to a nearly perfect circle, thereby effectively improving the bending accuracy of the angle bar.

[0023] Furthermore, the inside edge of the horizontal piece or the inside of the vertical piece of the angle bar is guided by an upstream auxiliary roller that is located upstream of the upstream bottom roller on the base plate in the angle bar feed direction, and the vertical piece of the angle bar, whose inside edge has been guided by the upstream auxiliary roller, is pressed against the upstream bottom roller by an upstream attachment roller that is located immediately upstream of the upstream bottom roller on the base plate in the angle bar feed direction. This allows the horizontal piece of the fed angle bar to be smoothly inserted into the gap between the large-diameter and small-diameter rollers of the top roller, and the vertical piece of the angle bar to be smoothly guided into the nip between the top roller and the upstream bottom roller, more effectively improving the bending accuracy of the angle bar.

[0024] In addition, the downstream attachment roller, located immediately downstream of the top roller on the substrate in the angle bar feed direction, presses the vertical piece of the angle bar, which has been bent further inward between the nip between the upstream bottom roller and the top roller, from the inside out, causing the horizontal piece of the angle bar to separate from the gap between the large and small diameter rollers of the top roller. This allows the horizontal piece of the angle bar to smoothly separate without getting caught in the gap between the large and small diameter rollers of the top roller, further effectively improving the bending accuracy of the angle bar.

[0025] In addition, when the end of the angle iron reaches the nip between the top roller and the downstream bottom roller, the center point of the angle iron moves downstream, but the angle iron is guided in a state where it is held down by the vertical piece abutting against the downstream auxiliary roller.As a result, when the end of the angle iron reaches the nip between the top roller and the downstream bottom roller, the center point of the angle iron moves downstream, but the downstream auxiliary roller holds it down, making it possible to guide the angle iron with high processing accuracy in a stable state.

[0026] Furthermore, the rotation axes of the upstream and downstream guide rollers are aligned approximately perpendicular to the feed direction of the angle bar, which is guided approximately horizontally by both guide rollers. This minimizes the sliding resistance when the angle bar is fed by both guide rollers, allowing the angle bar to be fed smoothly.

[0027] The straightening roller, downstream auxiliary roller, and downstream guide roller are supported on a downstream turntable that rotates about its axis near the downstream guide roller on the base, and each of the rollers is rotated about the axis of the downstream turntable according to the diameter of the angle bar when it is inwardly bent. As a result, by simply rotating the downstream turntable about its axis, the downstream guide roller can be quickly rotated so as to be approximately perpendicular to the direction in which the angle bar is fed, while also rotating the straightening roller and downstream auxiliary roller at the same time, and each of the rollers can be easily and quickly rotated according to the diameter of the angle bar when it is inwardly bent.

[0028] Furthermore, the upstream auxiliary roller and the upstream guide roller are supported on an upstream turntable that rotates about an axis near the upstream guide roller on the base, and when the angle bar is inwardly bent, each of the rollers is rotated about the axis of the upstream turntable according to the diameter of the angle bar. As a result, simply by rotating the upstream turntable about its axis, the upstream guide roller can be quickly rotated so as to be approximately perpendicular to the direction in which the angle bar is fed out, while simultaneously rotating the upstream auxiliary roller, allowing each of the rollers to be easily and quickly rotated according to the diameter of the angle bar to be inwardly bent. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a plan view showing a state immediately before the start of inward bending of an angle bar between a nip between a top roller and an upstream bottom roller by an inward bending device according to an embodiment of the present invention. FIG. [Figure 2] 2 is a plan view showing a state in which the inward bending device of FIG. 1 has started to inwardly bend an angle material between a nip between a top roller and an upstream bottom roller. FIG. [Figure 3] 3 is a partially cutaway cross-sectional view showing a state in which the angle material has been subjected to inward bending processing between a nip between a top roller and an upstream bottom roller by the inward bending device of FIG. 2. FIG. [Figure 4] FIG. 2 is a plan view showing the state in which the inward bending device of FIG. 1 has completed inward bending processing up to the rear end of one circular angle bar between the nip between the top roller and the downstream bottom roller to produce a circular body with high circularity. [Figure 5] 5 is a side view of the angle bar after it has been inwardly bent between the nip between the top roller and the downstream bottom roller by the inward bending device of FIG. 4, viewed from the downstream auxiliary roller side. [Figure 6] FIG. 5 is a cross-sectional view taken along line AA in FIG. [Figure 7] FIG. 5 is a cross-sectional view taken along line BB in FIG. [Figure 8]2 is a plan view showing a state in which the inward bending process has been completed up to the rear end of the band-shaped angle bar between the nip between the top roller and the downstream bottom roller so as to form a circular body with high circularity by the inward bending device of FIG. 1. [Figure 9] FIG. 9 is a cross-sectional view taken along line CC in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0031] FIG. 1 is a diagram illustrating an embodiment of the present invention. Inner bending device 2 is a plan view showing the state immediately before the angle material starts to be bent inward between the nip between the top roller and the bottom roller on the upstream side. Inner bending device 3 is a plan view showing the state in which the angle material starts to be inwardly bent between the nip between the top roller and the upstream bottom roller. Inner bending device 1 is a partially cutaway cross-sectional view showing the state after the angle material has been inwardly bent between the nip between the top roller and the upstream bottom roller.

[0032] As shown in Figures 1 to 3, X is an inward bending device for inward bending an angle bar L, and is equipped with three rollers 11 to 13 that rotate around vertically extending shafts 11a to 13a that are erected at approximately the center of a base 1. The angle bar L has a substantially horizontal horizontal piece La and a substantially vertical vertical piece Lb, and is formed with an L-shaped cross section, and is fed out in a strip shape.

[0033] Of the three rollers 11 to 13, roller 11 is a top roller that is driven to rotate around axis 11a (clockwise in Figs. 1 and 2). Meanwhile, the remaining two rollers 12 and 13 are an upstream bottom roller 12 and a downstream bottom roller 13 that are driven to rotate around axes 12a and 13a (counterclockwise in Figs. 1 and 2), and face the top roller 11 in that order from the upstream side in the feed direction of the angle bar L. Each of the rollers 11 to 13 is driven by an electric motor (not shown) equipped with a reducer.

[0034] Figure 4 is a diagram of Figure 1. Inner bending device 5 is a plan view showing the state in which the angle bar L has been inwardly bent up to the rear end of one circular body between the nip between the top roller 11 and the downstream bottom roller 13 so as to form a circular body with high circularity by X. Inner bending device 1 is a side view showing the state after the angle material L has been inwardly bent by X between the nip of the top roller 11 and the downstream bottom roller 13, as viewed from the downstream auxiliary roller side.

[0035] 4 and 5, the angle bar L that has been fed is passed through the nip between the top roller 11 and the upstream bottom roller 12 and the downstream bottom roller 13, and is subjected to inward bending. That is, the angle bar L is passed through the nip between the top roller 11 and the upstream bottom roller 12 and the downstream bottom roller 13 in that order, with the vertical piece Lb extending downward from the outer end of the horizontal piece La, and is subjected to inward bending.

[0036] The upstream bottom roller 12 is supported rotatably about a shaft 12a extending in the vertical direction on the upstream side of the substrate 1 in the feed direction of the angle iron L (left side in Figures 1 to 3), and bends the fed angle iron L inward along the circumferential surface of the top roller 11 between the nip with the top roller 11. The downstream bottom roller 13 is supported rotatably about a shaft 13a extending in the vertical direction on the substrate 1 downstream of the upstream bottom roller 12 in the feed direction of the angle iron L, and bends the angle iron L bent inward between the nip with the top roller 11 further along the circumferential surface of the top roller 11.

[0037] Fig. 6 is a cross-sectional view taken along line AA in Fig. 4, and Fig. 7 is a cross-sectional view taken along line BB in Fig. 4. As shown in Figs. 6 and 7, the top roller 11 has upper and lower large-diameter and small-diameter rollers 111 and 112, each with a different diameter. A liner 113 having a thickness of approximately 9 mm is interposed between the large-diameter and small-diameter rollers 111 and 112, leaving a gap S into which a horizontal piece La of an angle iron L can be inserted. The outer peripheral surface of the small-diameter roller 112 below the top roller 11 is formed into a tapered surface 114 that slopes downward so that the diameter increases. In this case, a horizontal piece La of an angle iron L having a thickness of approximately 8.7 mm is inserted into the gap S.

[0038] The upstream bottom roller 12 has upper and lower small-diameter and large-diameter rollers 121, 122 with different diameters, while the downstream bottom roller 13 has upper and lower small-diameter and large-diameter rollers 131, 132 with different diameters. When the angle bar L is bent inward along the circumferential surface of the top roller 11, the upstream and downstream bottom rollers 12, 13 press the vertical piece Lb of the angle bar L from the outside toward the lower small-diameter roller 112 of the top roller 11 with the lower end of the vertical piece Lb abutting the upper edge of the lower large-diameter rollers 122, 132.

[0039] A straightening roller 14 is provided on the substrate 1 downstream of the downstream bottom roller 13 in the direction of feeding of the angle iron L, which rotates around an axis 14a extending in the vertical direction on a downstream turntable 21, which will be described later. This straightening roller 14 presses outward the inner end of the horizontal piece La of the angle iron L so that the angle iron L, which has been bent further inward between the nip between the top roller 11 and the downstream bottom roller 13, becomes a nearly perfect circle, thereby forming a circular body with high circularity.

[0040] The center point O (shown in FIG. 4) of the angle iron L, which becomes a highly circular body when the inner end of the horizontal piece La is pressed outward by the straightening roller 14 and straightened, is located on an extension line m formed by extending the axis 11a of the top roller 11 toward the counter-upstream and downstream bottom rollers 12, 13 (downward in FIG. 4). At this time, the angle iron L continues to be fed even after it has become a highly circular body, so the leading end of the circular body that is rotating is lifted and placed on the top surface of the large-diameter roller 111 of the top roller 11, allowing it to continue rotating.

[0041] Furthermore, upstream of the upstream bottom roller 12 on the substrate 1 in the feeding direction of the angle iron L, an upstream auxiliary roller 15 is provided which rotates around a shaft 15a extending in the vertical direction on an upstream turntable 22 described below. This upstream auxiliary roller 15 guides the inner end of the horizontal piece La of the angle iron L that has been fed out.

[0042] Furthermore, an upstream attachment roller 16 that rotates about a vertically extending axis 16a is provided immediately upstream of the upstream bottom roller 12 on the substrate 1 in the direction in which the angle iron L is fed out. The upstream attachment roller 16 presses the vertical piece Lb of the angle iron L, the inner end of which is guided by the upstream auxiliary roller 15, against the small diameter roller 121 of the upstream bottom roller 12 by abutting it from the inside, so that the horizontal piece La of the angle iron L is fitted into the gap S between the large diameter and small diameter rollers 111, 112 of the top roller 11.

[0043] Furthermore, a downstream attachment roller 17 that rotates about a vertically extending shaft 17a is provided immediately downstream of the top roller 11 on the substrate 1 in the direction in which the angle iron L is fed. This downstream attachment roller 17 presses the vertical piece Lb of the angle iron L from the inside outward while maintaining the horizontality of the horizontal piece La of the angle iron L that has been bent further inward between the nip between the upstream bottom roller 12 and the top roller 11. When the lower end of the vertical piece Lb of the angle iron L is pressed from the inside outward by the downstream attachment roller 17, the horizontal piece La of the angle iron L is smoothly released from the gap S between the large-diameter and small-diameter rollers 111, 112 of the top roller 11.

[0044] Figure 8 is a diagram of Figure 1. Inner bending device 8 is a plan view showing the state in which the inward bending process has been completed up to the rear end of the strip-shaped angle bar L between the nip between the top roller 11 and the downstream bottom roller 13 so as to form a highly circular body by X. Also, FIG. 9 is a cross-sectional view taken along the line CC in FIG. 8.

[0045] 8 and 9, downstream of the top roller 11 on the substrate 1 in the direction in which the angle iron L is fed, there is provided a downstream auxiliary roller 18 that rotates on a downstream turntable 21 (described later) about an axis 18a extending in the vertical direction. When the end of the strip-shaped angle iron L reaches the nip between the top roller 11 and the downstream bottom roller 13, the downstream auxiliary roller 18 guides the angle iron L in the feeding direction while holding it down by contacting the vertical piece Lb. At this time, when the inner end of the horizontal piece La is being pressed outward by the straightening roller 14 and straightened, the center point O of the angle iron L becomes a center point O' (shown in FIG. 8) moved downstream on an orthogonal line n perpendicular to the extension line m when the vertical piece Lb comes into contact with the downstream auxiliary roller 18.

[0046] An upstream guide roller 19 is disposed laterally on the substrate 1 between the upstream auxiliary roller 15 and the upstream attachment roller 16. This upstream guide roller 19 is supported via a rotation shaft 19a on a fourth fixture 37 fixed to an upstream turntable 22 that rotates about a shaft 22a extending vertically above the substrate 1. The shaft 22a of the upstream turntable 22 is disposed near the approximate center of the upstream guide roller 19 on the substrate 1 in the direction of the rotation shaft.

[0047] The upstream guide roller 19 guides the angle bar L in the feeding direction by contacting the lower end of its vertical piece Lb on the upstream turntable 22 between the upstream auxiliary roller 15 and the upstream attachment roller 16. At this time, the rotation axis 19a of the upstream guide roller 19 is arranged to be approximately perpendicular to the feeding direction of the angle bar L guided by the upstream guide roller 19.

[0048] Meanwhile, downstream guide roller 20 is disposed laterally on substrate 1 between downstream auxiliary roller 18 and downstream attachment roller 17. This downstream guide roller 20 is supported via rotation shaft 20a on fourth fixture 41 fixed on upstream turntable 21 which rotates around shaft 21a extending vertically above substrate 1. Shaft 21a of downstream turntable 21 is provided near approximately the center position on substrate 1 in the direction of rotation shaft 20a of downstream guide roller 20.

[0049] The downstream guide roller 20 guides the angle bar L in the feeding direction by contacting the lower end of its vertical piece Lb on the downstream turntable 21 between the downstream auxiliary roller 18 and the downstream attachment roller 17. At this time, the rotation axis 20a of the downstream guide roller 20 is approximately perpendicular to the feeding direction of the angle bar L guided by the downstream guide roller 20.

[0050] Furthermore, a circular arc edge 211 having an arc shape centered on the axis 21a is provided on a portion of the periphery of the downstream turntable 21, and a plurality of holes 212, 212, ... are provided at equal intervals along this circular arc edge 211. Each hole 212 is selected according to the diameter of the angle bar L when the angle bar L is inwardly bent, and a bayonet pin 213 inserted into the base 1 through the selected hole 212 restricts rotation of the downstream turntable 21 around the axis 21a. The straightening roller 14, downstream auxiliary roller 18, and downstream guide roller 20 are configured to rotate around the axis 21a of the downstream turntable 21 according to the diameter of the angle bar L when the angle bar L is inwardly bent. Specifically, when bending the angle bar L inward to a larger diameter, the downstream turntable 21 rotates around the axis 21a (counterclockwise in Figure 8), while when bending the angle bar L inward to a smaller diameter, the downstream turntable 21 rotates around the axis 21a (clockwise in Figure 8).

[0051] Meanwhile, an arc-shaped edge 221 having an arc shape centered on the axis 22a is provided on part of the periphery of the upstream turntable 22, and a plurality of holes 222, 222, ... are provided at equal intervals along this arc edge 221. Each hole 222 is selected according to the diameter of the angle bar L when the angle bar L is inwardly bent, and a bayonet pin 223 inserted into the base 1 through the selected hole 222 restricts rotation of the upstream turntable 22 around the axis 22a. The upstream auxiliary roller 15, the upstream attachment roller 16, and the upstream guide roller 19 are configured to rotate around the axis 22a of the upstream turntable 22 according to the diameter of the angle bar L when the angle bar L is inwardly bent. Specifically, when the angle bar L is inwardly bent to a larger diameter, the upstream turntable 22 is rotated around the axis 22a (clockwise in Figure 8), whereas when the angle bar L is inwardly bent to a smaller diameter, the upstream turntable 22 is rotated around the axis 22a (counterclockwise in Figure 8).

[0052] The upstream attachment roller 16 is rotatably supported via a shaft 16a on a first support base 30, which is movable on the base 1 in a direction toward and away from the upstream bottom roller 12 (up and down in FIG. 8 ). This first support base 30 can move slightly toward and away from the upstream bottom roller 12 by advancing and retreating a first trapezoidal screw 32, which is threadedly attached to a first fixture 31 fixed to the base 1. This allows the amount of pressure applied by the upstream attachment roller 16 to press the vertical piece Lb of the angle bar L against the small-diameter roller 121 of the upstream bottom roller 12 to be slightly changed. In this case, when inward bending the angle bar L to a larger diameter, the upstream attachment roller 16 is advanced in a direction slightly approaching the upstream bottom roller 12. On the other hand, when inward bending the angle bar L to a smaller diameter, the upstream attachment roller 16 is retreated in a direction slightly separating it from the upstream bottom roller 12.

[0053] Meanwhile, the downstream attachment roller 17 is rotatably supported via a shaft 17a on a second support base 33 that is movable on the base 1 in a direction toward and away from the downstream bottom roller 13 (up and down in FIG. 8 ). This second support base 33 can move slightly toward and away from the downstream bottom roller 13 by advancing and retreating a second trapezoidal screw 35 that is threaded into a second fixture 34 fixed to the base 1. This allows for a slight change in the amount of pressure applied by the downstream attachment roller 17 to press the vertical piece Lb of the angle bar L against the small-diameter roller 131 of the downstream bottom roller 13. In this case, when inward bending the angle bar L to a larger diameter, the downstream attachment roller 17 is advanced in a direction that brings it slightly closer to the downstream bottom roller 13. On the other hand, when inward bending the angle bar L to a smaller diameter, the downstream attachment roller 17 is retreated in a direction that moves it slightly away from the downstream bottom roller 13.

[0054] The upstream auxiliary roller 15 is rotatably supported via shaft 15a on a third support base 36 that is movable on the upstream turntable 22 in parallel to the rotation shaft 19a of the upstream guide roller 19. A third trapezoidal screw 38 extending parallel to the rotation shaft 19a of the upstream guide roller 19 is threadedly attached to a third fixture 37 that supports the rotation shaft 19a of the upstream guide roller 19. A substantially rectangular parallelepiped upstream spacer block 39 is detachably interposed between the tip (the upper end in FIG. 8 ) of the third trapezoidal screw 38 and the third support base 36. In this case, by removing the upstream spacer block 39, the third trapezoidal screw 38 can be smoothly advanced and advanced.

[0055] Furthermore, the downstream-side auxiliary roller 18 is rotatably supported via a shaft 18a on a fourth support base 40 that is movable on the downstream-side turntable 21 in parallel to the rotation axis 20a of the downstream-side guide roller 20. A fourth trapezoidal screw 42 that extends parallel to the rotation axis 20a of the downstream-side guide roller 20 is threadedly attached to a fourth fixture 41 that supports the rotation axis 20a of the downstream-side guide roller 20. Furthermore, the straightening roller 14 is rotatably supported via a shaft 14a on a fifth support base 43 that is movable on the screw axis of the fourth trapezoidal screw 42 on the downstream-side turntable 21.

[0056] The tip of the fourth trapezoidal screw 42 abuts against one end (the left end in FIG. 8 ) of the fifth support base 43. A downstream spacer block 44 having a substantially rectangular parallelepiped shape is detachably interposed between the other end (the right end in FIG. 8 ) of the fifth support base 43 and the fourth support base 40. By removing the downstream spacer block 44, the distance between the fifth support base 43 and the fourth support base 40 can be changed by replacing it with another downstream spacer block of a different length, and the fourth trapezoidal screw 42 can be smoothly advanced and advanced. In this case, the length of the downstream spacer block 44 in the direction of the fourth trapezoidal screw 42 is set so that the distance between the straightening roller 14 and the downstream auxiliary roller 18 is maintained at 50 mm.

[0057] Therefore, in this embodiment, when the angle iron L is bent inward along the peripheral surface of the top roller 11, the horizontal piece La of the angle iron L is inserted into the gap S between the upper and lower large-diameter and small-diameter rollers 111, 112 of the top roller 11, while the vertical piece Lb of the angle iron L is pressed from the outside toward the lower small-diameter roller 112 of the top roller 11 by the upper small-diameter rollers 121, 131 with its lower end abutting the upper edge of the lower large-diameter rollers 122, 132 of each bottom roller 12, 13. For this reason, when the angle iron L is bent inward, the horizontal piece La of the angle iron L is inserted into the gap S between the large-diameter and small-diameter rollers 111, 112 of the top roller 11, and is constrained from the top and bottom directions, and the lower end, which is the open end of the vertical piece Lb, which is pressed from the outside by the upper small-diameter rollers 121, 131 toward the lower small-diameter roller 112 of the top roller 11, abuts against the upper edges of the lower large-diameter rollers 122, 132 of each bottom roller 12, 13. As a result, when bending the angle iron L to form a circular body with high circularity, it is not necessary to move the bottom rollers 12, 13 back and forth, and complicated control of the bottom rollers 12, 13 can be eliminated.

[0058] Furthermore, when the angle iron L passes through the nip between the top roller 11 and each bottom roller 12, 13, the horizontal piece La of the angle iron L is inserted into the gap S between the large-diameter and small-diameter rollers 111, 112 of the top roller 11 and is restrained from the top and bottom directions, and the lower end of the vertical piece Lb abuts against the upper edges of the large-diameter rollers 122, 132 of each bottom roller 12, 13 and is restrained.This prevents accidental deformation due to stress applied during bending between the nip between the top roller 11 and the upstream and downstream bottom rollers 12, 13, thereby improving the bending accuracy of the angle iron L.

[0059] Furthermore, the outer peripheral surface of the small diameter roller 112 of the top roller 11 is formed into a tapered surface 114 that slopes downward so that the diameter increases. This suppresses deformation of the vertical piece Lb to a narrow angle of 90° or less relative to the horizontal piece La due to stress acting when inwardly bending the angle bar L having an L-shaped cross section, thereby further improving the bending accuracy of the angle bar L.

[0060] Furthermore, by using a correction roller 14 located downstream of the downstream bottom roller 13 on the substrate 1 in the direction of feeding of the angle iron L, the inner end of the horizontal piece La of the angle iron L, which has been bent further inward between the nip between the top roller 11 and the downstream bottom roller 13, is pressed outward, thereby expanding the diameter of the angle iron L and correcting it so that it becomes a nearly perfect circle. This effectively improves the bending accuracy of the angle iron L.

[0061] Furthermore, the inner end of the horizontal piece La of the angle iron L is guided by the upstream auxiliary roller 15, which is located upstream of the upstream bottom roller 12 on the substrate 1 in the feed-out direction of the angle iron L, and the vertical piece Lb of the angle iron L, whose inner end has been guided by the upstream auxiliary roller 15, is pressed against the small diameter roller 121 of the upstream bottom roller 12 by the upstream attachment roller 16, which is located immediately upstream of the upstream bottom roller 12 on the substrate 1 in the feed-out direction of the angle iron L, by contact from the inside. This allows the horizontal piece La of the fed angle iron L to be smoothly inserted into the gap S between the large diameter and small diameter rollers 111, 112 of the top roller 11, and the vertical piece Lb of the angle iron L to be smoothly guided into the nip between the top roller 11 and the upstream bottom roller 12, thereby more effectively improving the bending accuracy of the angle iron L.

[0062] Furthermore, the downstream attachment roller 17, which is located immediately downstream of the top roller 11 on the substrate 1 in the feeding direction of the angle iron L, presses the vertical piece Lb of the angle iron L from the inside outward while maintaining the horizontality of the horizontal piece La of the angle iron L, which has been bent further inward between the nip between the upstream bottom roller 12 and the top roller 11. Therefore, when the lower end of the vertical piece Lb of the angle iron L is pressed outward from the inside by the downstream attachment roller 17, the horizontal piece La is smoothly released from the gap S between the large-diameter and small-diameter rollers 111, 112 of the top roller 11. This allows the horizontal piece La of the angle iron L to be smoothly released without being caught in the gap S between the large-diameter and small-diameter rollers 111, 112 of the top roller 11, and further effectively improves the bending accuracy of the angle iron L.

[0063] Furthermore, when the end of the angle iron L reaches the nip between the top roller 11 and the downstream bottom roller 13, the center point O of the angle iron L moves to the downstream center point O', but the angle iron L is guided in a restrained state by the vertical piece Lb abutting against the downstream auxiliary roller 18. As a result, when the end of the angle iron L reaches the nip between the top roller 11 and the downstream bottom roller 13, the center point O of the angle iron L moves to the downstream center point O', but the angle iron L is restrained by the downstream auxiliary roller 18, making it possible to guide the angle iron L with high processing accuracy in a stable state.

[0064] Furthermore, the rotation axis 19a of the upstream guide roller 19 and the rotation axis 20a of the downstream guide roller 20 are made to be approximately perpendicular to the feeding direction of the angle iron L guided by both guide rollers 19, 20. This minimizes the sliding resistance when the angle iron L is fed by both guide rollers 19, 20, allowing the angle iron L to be fed smoothly.

[0065] In addition, the straightening roller 14, downstream auxiliary roller 18, and downstream guide roller 20 are supported on a downstream turntable 21 that rotates around an axis 21a near the approximate center position of the substrate 1 in the direction of the rotation axis 20a of the downstream guide roller 20, and each of the rollers 14, 18, and 20 is rotated around the axis 21a of the downstream turntable 21 according to the size of the diameter when the angle bar L is inwardly bent. As a result, simply by rotating the downstream turntable 21 about the axis 21a, the downstream guide roller 20 can be quickly rotated so as to be approximately perpendicular to the feed direction of the angle bar L, while simultaneously rotating the straightening roller 14 and downstream auxiliary roller 18, and each of the rollers 14, 18, and 20 can be easily and quickly rotated according to the size of the diameter when the angle bar L is inwardly bent.

[0066] Furthermore, the upstream auxiliary roller 15 and the upstream guide roller 19 are supported on an upstream turntable 22 that rotates around an axis 22a near the approximate center position of the substrate 1 in the direction of the rotation axis 19a of the upstream guide roller 19, and when inward bending the angle bar L, the rollers 15, 19 are rotated around the axis 22a of the upstream turntable 22 in accordance with the diameter of the angle bar L. As a result, simply by rotating the upstream turntable 22 around the axis 22a, the upstream guide roller 19 can be quickly rotated so as to be approximately perpendicular to the feed direction of the angle bar L, while simultaneously rotating the upstream auxiliary roller 15, and the rollers 15, 19 can be easily and quickly rotated in accordance with the diameter of the angle bar L to be inward bent.

[0067] The present invention is not limited to the above-described embodiment, and includes various other modified examples. For example, in this embodiment, the length of the downstream spacer block 44 in the direction of the fourth trapezoidal thread 42 is set so that the distance between the straightening roller 14 and the downstream auxiliary roller 18 is maintained at 50 mm, but the length of the downstream spacer block in the direction of the fourth trapezoidal thread 42 may be set so that the distance between the straightening roller and the downstream auxiliary roller is 30 mm to less than 50 mm.

[0068] In addition, in this embodiment, the correction roller 14 corrects the inner end of the horizontal piece La of the angle iron L by pressing it outward so that the angle iron L has an approximately perfect circular shape, but it is also possible to correct the inner side of the vertical piece of the angle iron by pressing it outward with the correction roller.

[0069] In addition, in this embodiment, the inner end of the horizontal piece La of the fed angle iron L is guided by the upstream auxiliary roller 15, but the inner side of the vertical piece of the fed angle iron may also be guided by the upstream auxiliary roller.

[0070] In addition, in this embodiment, the straightening roller 14, downstream auxiliary roller 18, and downstream guide roller 20 are supported on a downstream turntable 21 that rotates around axis 21a on the substrate 1, but the straightening roller, downstream auxiliary roller, and downstream guide roller may also be supported on the substrate so as not to be rotatable.

[0071] In addition, in this embodiment, the upstream auxiliary roller 15 and the upstream guide roller 19 are supported on an upstream turntable 22 that rotates around an axis 22a on the substrate 1, but the upstream auxiliary roller and the upstream guide roller may also be supported on the substrate so that they cannot rotate.

[0072] Furthermore, in this embodiment, the top roller 11 is driven to rotate clockwise, and the upstream and downstream bottom rollers 12, 13 are each driven to rotate counterclockwise, but it is also possible to drive the top roller to rotate counterclockwise, and the upstream and downstream bottom rollers to rotate clockwise, in which case the layout of the upstream and downstream rollers must be reversed. [Explanation of symbols]

[0073] 1 board 11 Top Roller 11a Top roller shaft 111 Large diameter roller of top roller 114 Tapered surface 12 Upstream bottom roller 12a Shaft of upstream bottom roller 121 Small diameter roller of the upstream bottom roller 122 Large diameter roller of the upstream bottom roller 13 Downstream bottom roller 13a Downstream bottom roller shaft 131 Small diameter roller of downstream bottom roller 132 Large diameter roller of downstream bottom roller 14 Correction roller 14a Shaft of straightening roller 15 Upstream auxiliary roller 15a Shaft of upstream auxiliary roller 16 Upstream attachment roller 16a Upstream attachment roller shaft 17 Downstream attachment roller 17a Downstream attachment roller shaft 18 Downstream auxiliary roller 18a Downstream auxiliary roller shaft 19 Upstream guide roller 19a Rotation shaft of the upstream guide roller 20 Downstream guide roller 20a Rotation shaft of downstream guide roller 21 Downstream turntable 21a Downstream turntable 22 Upstream turntable 22a Upstream turntable L angle material La horizontal piece Lb vertical piece O,O´ Center point of angle bar S Gap X-inside bending device

Claims

1. An inward bending device for inward bending an angle bar having an L-shaped cross section, which is fed out in a strip shape, by passing it through a nip between one of three rollers and two other rollers which face each other in order from the upstream side in the feeding direction of the angle bar, to form a circular body with high circularity, The three rollers are: a top roller that rotates in a forward direction around an axis extending vertically on the substrate; an upstream bottom roller that is driven in a reverse rotation direction about an axis extending in a vertical direction on the upstream side of the angle bar feed direction on the substrate, and bends the fed angle bar inward along the circumferential surface of the top roller between the nip between the upstream bottom roller and the top roller; a downstream bottom roller that is driven in a reverse rotation direction about an axis extending in a vertical direction on the substrate downstream of the upstream bottom roller in the angle bar feed direction, and that bends the angle bar bent inward between the nip between the upstream bottom roller and the top roller further inward along the circumferential surface of the top roller between the nip between the upstream bottom roller and the top roller; is applied, The top roller has a large diameter roller and a small diameter roller on top and bottom, which have different diameters, and a gap is formed between the large diameter roller and the small diameter roller, into which the substantially horizontal horizontal piece of the angle iron is inserted; The upstream and downstream bottom rollers have small-diameter and large-diameter rollers on top and bottom, each having a different diameter, and when the angle bar is bent inward along the circumferential surface of the top roller, the lower end of the substantially vertical vertical part of the angle bar is in contact with the upper edge of the lower large-diameter roller, and the upper small-diameter roller presses the vertical part of the angle bar from the outside toward the lower small-diameter roller of the top roller; The angle bar inward bending device is characterized in that the outer peripheral surface of the small diameter roller of the top roller is formed into a tapered surface that inclines so that the diameter increases as it goes downward.

2. An inward bending device for angle iron as described in claim 1, which is provided with a straightening roller that rotates around an axis extending vertically downstream of the downstream bottom roller on the base plate in the direction of feeding of the angle iron, and that straightens the angle iron by pressing outward the inner end of the horizontal piece or the inside of the vertical piece of the angle iron so that the angle iron bent further inward between the nip between the top roller and the downstream bottom roller becomes approximately circular.

3. An upstream auxiliary roller that rotates about an axis extending in the vertical direction on the upstream side of the upstream bottom roller on the base plate in the angle bar feed direction and that guides the inner end of the horizontal piece or the inside of the vertical piece of the angle bar that has been fed out; an upstream attachment roller that rotates about an axis extending in the vertical direction immediately upstream of the upstream bottom roller on the base plate in the direction of feeding of the angle iron, and that presses the vertical piece of the angle iron, the inner end of which is guided by the upstream auxiliary roller, against the upstream bottom roller by abutting from the inside; 3. The angle member inward bending device according to claim 2, further comprising:

4. An inward bending device for angle iron as described in Claim 3, comprising a downstream attachment roller which rotates around an axis extending in the vertical direction immediately downstream of the top roller on the base plate in the direction of feeding of the angle iron, and which presses the vertical piece of the angle iron from the inside outward while maintaining the horizontality of the horizontal piece of the angle iron bent further inward between the nip between the upstream bottom roller and the top roller.

5. An inward bending device for angle iron as described in Claim 4, which is provided with a downstream auxiliary roller that rotates around an axis extending in the vertical direction downstream of the top roller on the base plate in the direction of feeding of the angle iron, and guides the angle iron, whose center point moves downstream when the end of the angle iron reaches the nip between the top roller and the downstream bottom roller, while holding it down by abutting against its vertical part.

6. Between the upstream auxiliary roller and the upstream attachment roller on the base plate, an upstream guide roller is provided horizontally to guide the angle bar approximately horizontally in the sending direction by contacting the lower end of the vertical piece between the two rollers, and A downstream guide roller is provided between the downstream auxiliary roller and the downstream attachment roller to guide the angle bar substantially horizontally in the feed direction by contacting the lower end of the vertical piece of the downstream guide roller between the two rollers, 6. The apparatus for bending an angle bar inward according to claim 5, wherein the rotation axes of the upstream and downstream guide rollers are each substantially perpendicular to the direction in which the angle bar is fed out by the guide rollers.

7. An angle bar inward bending device as described in Claim 6, wherein the correction roller, the downstream auxiliary roller and the downstream guide roller are supported on a downstream turntable which rotates around an axis extending vertically near the downstream guide roller on the base, and when the angle bar is inwardly bent, it is rotated around the axis of the downstream turntable depending on the diameter of the angle bar.

8. An angle bar inward bending device as described in Claim 7, wherein the upstream auxiliary roller and the upstream guide roller are supported on an upstream turntable which rotates around an axis extending vertically near the upstream guide roller on the base, and when the angle bar is inwardly bent, the angle bar is rotated around the axis of the upstream turntable depending on the diameter of the angle bar.

Images