JPH09144126A - Manufacture of ditch covering structural member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a ditch covering structural member having antislipping projections with prescribed height and prescribed pitch by blanking the top face of a longitudinal projected stripe hot-rolled to be formed on an end on one side across the width of a shape steel. SOLUTION: A shape steel of rectangular cross-section is vertically held and inserted into the first hot rolling rolls, and pressurized in crosswise direction to form a longitudinal stripe 11 on one end side across the width. Then, the shape steel is held horizontally held and inserted into the second rolling rolls, and pressurized in the direction of thickness. Both main central sides of the shape steel are squeezed for the cross-section to be converted into an I-shaped cross-section. Simultaneously with this, the shape steel is squeezed from both sides in order for the height to be increased up to 2.0mm to 4.0mm and the thickness to be thimmed. Successively, the shape steel is horizontally held and inserted into the third rolling rolls to be pressurized and finished to specified dimensional accuracy. Finally, the top face of the projected stripe 11 is blanked by a press die having rugged surface to form anti-slipping projections 12, and thus to form a ditch covering structural member 10. The pitch of the projected parts of the projections 12 is preferably determined to be 10.0, 12.5 or 16.7mm in order for the pitch to conform to the welding position of a twist bar.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural material for a groove lid, which is made of a shaped steel having a rectangular cross section, an inverted trapezoidal shape or an I-shaped shape, and more particularly, a structure having a projection for preventing slippage on a side end surface on one widthwise end side The present invention relates to a method for manufacturing a structural material.

[0002]

2. Description of the Related Art As shown in FIG. 8, when a groove cover is attached to a side groove or a manhole A of a road, a groove cover B having a large load-bearing strength that enables passage of an automobile is composed of an upright strip. A large number of short strips b between the long sides on both sides of the rectangular outer frame a
Are welded at both ends and installed in parallel, and a plurality of twisted wire rods (twist bars) c or round bars formed by twisting a wire rod having a substantially square cross section are arranged in parallel in the direction orthogonal to the short strip plate and welded. By doing so, a lattice-shaped one has been widely used.

[0003] However, although a rectangular section steel or an I-shaped section steel is generally used for the short strip, it is used because both surfaces on the short side of the section are flat. It was dangerous that an automobile tire passing over the groove lid easily slips along the flat upper surface of the mold steel.

Therefore, conventionally, as shown in FIG. 9, a slip preventing projection is punched with a press die at a constant pitch along the longitudinal direction on one surface of the short side of the section of the section steel having a rectangular section. The formed groove lid structural material is used.

[0005]

However, the projecting portion of the structural material is formed by punching out an unnecessary portion of the projecting shape by pressing during cold working to form the above-mentioned one surface of the shape steel, that is, the side end surface on one end in the width direction. Since it is formed by the method of punching into unevenness corresponding to the part, it is 5 at normal punching pressure.
There is a limit to the processing up to a plate thickness of about mm, and if a plate thickness more than that is pushed out, there is a problem that the projection itself deforms the shape and the dimensional accuracy is not obtained.

Therefore, the height 5 used for heavy loads
Steel plate with a rectangular or I-shaped cross section of 0 mm or more has a plate thickness of 5 mm.
However, this method is difficult to process.

[0007]

In view of the above-mentioned circumstances, the present invention provides a groove lid structure material capable of exhibiting a large slip preventing effect even in a die steel having a plate thickness of more than 5 mm. It is intended to provide a manufacturing method.

That is, in order to achieve the above-mentioned object, the groove lid structural material manufacturing method according to the present invention is characterized in that, in hot rolling, a section steel having a rectangular cross section, an inverted trapezoidal shape or an I shape is formed between a pair of rolls. In addition to printing pressure in the direction, a ridge extending along the longitudinal direction of the mold steel is formed on the side end surface on one side in the width direction of the mold steel by the pressure applied by the circumferential groove provided on one of these rolls, and the thickness of the ridge is 5 mm In the following, a structure is adopted in which the tops of the ridges are punched with a press die having an uneven shape to form protrusions on the upper portions of the ridges at predetermined intervals.

Further, according to the present invention, the projection pitch of the projections is set to 10.0, 12.5 or 16.7 mm, and the total height of the projections and the projections is 2.0 to 4. 0.0 m
A preferred embodiment is that it is set to m.

[0010]

According to the method of the present invention, since the ridge formed on the side end surface of the mold steel is thinner than the main body of the mold steel, a protrusion having a sufficient height can be easily formed by a press die.

Further, the protrusions can be punched so that the corners can be processed into acute angles, and a high slip preventing effect can be provided.

Further, since a plurality of twist bars or round bars are arranged in parallel in the direction orthogonal to each other and welded at a pitch of 50 or 100 mm, the protrusion pitch of the protrusions is 10.
By setting it to 0, 12.5 or 16.7 mm, the welding position is always the same position on the protrusion, and stable welding is possible.

Furthermore, it has been proved as a result of experiments that the anti-slip action is improved by setting the total height of the projections and the ridges to 2.0 mm to 4.0 mm.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be specifically described below with reference to the illustrated embodiments. 1 to 4 show an example of a manufacturing process by hot rolling and press punching of the groove lid structural material 10 shown in FIG.

First, in the first step shown in FIGS. 1A and 1B,
A holding circumferential groove 1a having a ridge forming circumferential groove 1b on the groove bottom of the roll R1 and a holding circumferential groove 2 of the roll R2 facing the holding circumferential groove 1a.
A die steel 10a having a rectangular cross-section is inserted between a and a in a vertical shape whose main surface is orthogonal to the roll axis direction, and printing pressure is applied in the die steel width direction. As a result, the mold steel 10a becomes the mold steel 10b having the ridge 11a having the height h1 along the longitudinal direction on the side end surface on the one widthwise side.

Next, in the second step shown in FIGS. 2A and 2B,
Both are narrow convex peripheral surface portions 3a and 4a and wide convex peripheral surface portions 3b and 4b.
Between the rolls R3 and R4 on the same opposing peripheral surface having the annular concave portions 3c and 4c between them, the shape steel 10b is a horizontal shape whose main surface is parallel to the roll axial direction, and the ridge 11a has a narrow convex peripheral surface portion 3a. , 4a so as to be located between them, and printing pressure is applied in the thickness direction. As a result, in the shape steel 10b, the central portions of both main surfaces are narrowed and converted into a sectional view I-shape, and at the same time, the ridges 11 are formed.
a is narrowed down from its both side surfaces to increase the height to h2 and is thinned to be the shaped steel 10c having the ridges 11b.

Subsequently, in a third step shown in FIG. 3, the wide convex peripheral surface portion 5c, between the annular concave portions 5a, 6a and 5b, 6b is formed.
Similarly to the second step, the die steel 10d is horizontally inserted between the rolls R5 and R6 having the same facing peripheral surface and having 6c, and printing pressure is applied. As a result, the mold steel 10d is finished into a mold steel 10e having a predetermined dimensional accuracy.

Finally, in the fourth step shown in FIG. 4, the top surface of the ridge is punched out by a press die having an uneven shape to form protrusions on the upper portion of the ridge at predetermined intervals to form the groove lid structural material 10. Becomes

The structure material for the groove lid manufactured by the method of the present invention is not limited to one in which the main body has an I-shaped cross section, and
A structural member whose main body has a rectangular cross section or an inverted trapezoidal shape as shown in FIGS.

In the structural materials 13 and 14 as described above, the rolls R3, R4, R5 and R6 of the second step and the third step have flat surfaces or tapered contact portions with both main surfaces of the structural materials 13 and 14, respectively. What is a surface may be used.

In order to obtain a sufficient slip effect, the height of the protrusion is optimally in the range of about 2.0 to 4.0 mm, and the height of the ridge forming the bottom thereof is 1.5 to 3. It is good to set it to about 0.5 mm.

Although the pitch interval of the protrusions can be set variously, in order to match the welding position of the twist bar,
0, 12.5 or 16.7 mm is preferred.

On the other hand, the thickness of the structural material is about 5 to 10 mm,
The width is preferably about 25 to 100 mm.

FIG. 7 shows an example of a groove lid using the groove lid structural material 10 obtained by the method of the present invention.

As shown in the figure, the groove lid has a rectangular box shape whose main surface is a lattice, and is surrounded by upright left and right short strips and front and rear long strips made of normal steel, and is surrounded by the front and back. Between the long strips of the above, a short length of upright structural material with the side end surface having the ridges and projections facing up is installed in parallel at a constant interval by welding both ends thereof, and these structural materials and A plurality of orthogonal twisted wire rods or round rods each having a substantially square cross section are fixed at predetermined intervals across the upper edge portions of the structural material by electric resistance welding or the like to form vertical and horizontal lattices.

[0026]

According to the method of the present invention, since the convex strip is provided on the side end surface on the one end side in the width direction of the shape steel and the projecting portion is formed by punching this with a press, the projecting portion is formed even with a thick plate member. Therefore, it is possible to easily manufacture the groove lid structural member having a high protrusion having a large slip prevention effect.

[Brief description of the drawings]

FIG. 1A is a perspective view of a first step in one embodiment of the method of the present invention.

[FIG. 1B] A sectional view of the printing portion in the same process.

FIG. 2A is a perspective view of the second step.

[FIG. 2B] A sectional view of the printing portion in the same step

FIG. 3 is a perspective view of the same third step.

FIG. 4 is a perspective view of the fourth step.

FIG. 5: Structural member for groove lid obtained by the method of the present invention

FIG. 6 shows another example of the same structural material.

FIG. 7 is a perspective view of a groove lid using the same structural material.

FIG. 8 is a vertical cross-sectional view showing how the groove lid is attached.

[FIG. 9] Conventional anti-slip member

[Explanation of symbols]

 R1, R2 Rolls forming ridges R3, R4 Rolls for narrowing ridges R5, R6 Rolls for finishing to predetermined dimensional accuracy 10 Structural material for groove lids 10a to 10e type steel 11, 11a, 11b Convex ridges 12 Protrusions 13 Cross section Rectangular groove lid structural material 14 Reverse trapezoidal groove lid structural material

Claims (3)

[Claims] 1. In hot rolling, a mold steel having a rectangular cross section, an inverted trapezoidal shape or an I-shape is pressed in a width direction of the mold steel between a pair of rolls, and the mold steel is formed by a circumferential groove provided in one of the rolls. A convex strip is formed on the side end surface on one side in the width direction along the longitudinal direction of the shape steel, and the convex top surface is punched with a press die having an uneven shape to form protrusions at predetermined intervals on the convex upper portion. A method for manufacturing a structural material for a groove lid, characterized in that 2. The protrusion pitch of the protrusions is 10.0, 1
The method for manufacturing a groove cover structural material according to claim 1, wherein the groove cover structural material is set to 2.5 or 16.7 mm. 3. The total height of the protrusion and the ridge is 2.0 to
The method for manufacturing a structural material for a groove lid according to claim 1 or 2, wherein the method is set to 4.0 mm.