JPH03210923A - Manufacture of rib lath - Google Patents

Abstract

PURPOSE:To easily obtain a rib lath which is large in strength and is not broken easily by bending and tensile stresses by giving bent shapes to both end parts of each slit in such an extent that they turn inward on the top side, outward on the bottom side and make an acute angle respectively to the lengthwise direction of a sheet. CONSTITUTION:Since both end parts 18a, 18b of the slit 18 are bent, the bottom part 22 of a side piece 20a branched from a vertical rib 19 is large in width and in strength and, further, since the slit cuts into the vertical rib 19, when the sheet 17 is stretched in a width direction, bending and tensile strengths disperse and no crack is generated in the bottom part 22. Since the bent directions of both end parts 18a, 18b of slit 18 make an acute angle theta to the lengthwise direction (h) of the sheet 17, though the rib lath obtained is bent to the side of a projecting face of the vertical rib 19, the slit cannot be expanded and though the slit is expanded to some extent, the vertical rib 19 is not broken because a distance for short circuit is long.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing metal lath, particularly rib lath having longitudinal ribs at appropriate intervals, used as weir plates of formwork in the construction of concrete structures.

Conventional technology and its problems In general, this type of re-brass is made by slitting a strip-shaped thin metal plate, and then roll-forming it into cross-sections U at appropriate intervals.
It is manufactured by forming vertical ribs in the shape of a letter, and then stretching the thin plate in the width direction to widen the slits to form a mesh.

The above-mentioned slit processing is usually performed by forming a zigzag-shaped blade portion (
By intermittent movement of the thin metal plate between an upper mold (2) having a blade part 2a) and a lower mold (3) having a similar blade part (3a) that fits into the blade part (2a), The fitted trapezoidal teeth (1) (1) are sheared at both sides (la) (1a), and a convex slit (4) is cut into the thin plate (5) as shown in Figure 6.
) are formed densely at regular intervals along the longitudinal direction. In addition, the top part (1b) of the trapezoidal tooth (1) (1) to be fitted
A gap t is set between the trough and the trough (1c), and since the thin plate (5) is not sheared in this part, a continuous non-slit area (5a) is created in the longitudinal direction, and the area (5a) is This will form the vertical rib. In addition, the upper and lower molds (2) and (3) are usually provided with a plurality of grooves (6) (three in the figure) that cross the blade parts (2a) and (3a), and these grooves (6) and The thin plate (
5) is not sheared and each slit (4) becomes discontinuous at each groove (6), so the stretching described above creates ribs with a wide mesh consisting of horizontal sides and vertical pieces between the vertical ribs. can get.

However, in the conventional general-purpose Librass mentioned above, thin plates (
5), as shown in Figure 7, bending and tensile stress concentrates on the base of the horizontal side (8), which is the branching point from the vertical rib (7), causing cracks (9) and crystallization. However, there was a problem in that it easily broke at the crack (9) portion during handling and use.

Therefore, as a means to deal with this, both ends of each slit (4) formed in the thin plate (5) are rounded (4a) as shown in Fig. 8, and the width of the base of the horizontal piece branching from the vertical rib is widened. Therefore, a method has been proposed to prevent the above-mentioned breakage by increasing the strength (Japanese Patent Laid-Open No. 180623/1983).
Publication No.).

However, with the above proposed method, as shown in Figure 9,
Due to the rounded shape (4a), opposing notches are formed on both sides of the vertical rib (7) along the transverse direction, so when the rib brass is bent toward the convex side of the vertical rib (7), the notches on both sides are formed. A new problem has arisen in that the longitudinal ribs (7) are likely to open and elongate, shorting each other and causing the longitudinal ribs (7) to break.

Means for Solving the Problems The present invention has been made to solve the problems of the conventional art, and it has been developed to use ribrass that has high strength and does not break when subjected to bending and tensile stress in any direction. The purpose is to provide a simple manufacturing method.

That is, in order to achieve the above-mentioned object, the method for manufacturing Ribrass according to the present invention includes forming convex-shaped slits (18) in a band-shaped metal thin plate (17) at regular intervals along the longitudinal direction of the thin plate, and then , the non-slit region (17a) continuous in the longitudinal direction of the thin plate (17) is curved into a groove shape to form a longitudinal rib (
19) and stretching the thin plate (17) in the width direction to form a mesh (20).
a) (18b) to the top side (18a) of the above convex shape
The thin plate is bent inward, and the bottom side (18b) is bent outward at an acute angle (θ) with respect to the longitudinal direction of the thin plate.

Both ends (18a) (18b) of the working slit (18)
) is bent, the base (22) of the horizontal piece (20a) branching from the vertical rib (19) becomes wider and stronger, and has a shape cut into the vertical rib (19). Therefore, the bending and tensile stresses caused by stretching the thin plate (17) in the width direction are dispersed, and the root portion (2
2) No cracks will occur.

Therefore, both ends (18a) (18) of the slit (18)
Since the refraction direction of b) is at an acute angle (θ) with respect to the longitudinal direction (h) of the thin plate (17), the obtained replus (2
Even if 1) is bent toward the convex side of the vertical rib (19), the notch will not extend <<, and even if it stretches to a certain extent, the distance to short circuit is long, so it will almost never lead to breakage of the vertical rib (19). .

EXAMPLE Hereinafter, an example of the present invention will be explained with reference to the drawings.

FIG. 1 shows an example of a press mold used in the method of this invention. This mold (11) has a zigzag-shaped blade portion (1
an upper die (12) having a blade 2a) and a lower die (13) having a similar blade (13a) that fits into the blade (12a);
It is made up of. However, the double-edged part (12a)
The teeth (14) of (13a) are formed into a substantially trapezoidal shape, and the side portions (14a) of (14a) that come into contact with each other when mating are engaged.
The space between the upper and lower molds (12) and (13) is set to a clearance that can shear a thin metal plate such as a thin steel plate sandwiched between the upper and lower molds (12) and (13), and the space between the top part (14b) and the valley part (14c) when mated is set. constitutes a gap (1) that does not shear the thin plate, but
A gently sloped part (15) in which the vicinity of the top and the vicinity of the valley of each side part (14a) are bent in a dogleg shape with respect to the main ridgeline (f).
is doing. In addition, three grooves (16) are formed on the lower surface side of the blade part (12a) of the upper mold (12) and on the upper surface side of the blade part (13a) of the lower mold (13), which extend in the direction across the teeth (14). , so as to connect in a straight line across the double edge portions (12a) (13a) when fitted, and the top portion (1) of each tooth (14).
4b) and the valley part (14c) are formed in parallel so as to divide the space into four equal parts.

In the slitting process, a thin metal plate such as a strip-shaped foil steel plate is first
The upper and lower molds (12) are moved intermittently so as to pass along the vertical direction in the figure, and the mold (11) is operated during each stop period.
(13) This is done by pressing the thin plate between. As a result, as shown in FIG. 2, the thin plate (17) has both sides (14a) of the tooth (14)
Convex-shaped slits (18) corresponding to the slits are formed densely at regular intervals along the longitudinal direction. However, each slit (
Both ends (18a) (18a) of 18) have teeth (
Corresponding to the gently sloped part (15) of 14), the convex top side end (18a) faces inward, and the hemline end (18b)
), the shape is bent outward and at an acute angle (θ) with respect to the longitudinal direction (h) of the thin plate. Moreover, each slit (18) is connected to the valley groove (1) of the press die (11).
Since the thin plate (17) is not sheared at position 6), it becomes discontinuous and is divided into four parts.

After forming the slits (18) in this way, a continuous non-slit area (
17a) is bent into a groove shape by rolling or the like to continuously form vertical ribs such as a U-shaped cross section, and then the thin plate (17) is stretched in the width direction. As a result, each slit (18) is expanded and the vertical rib (19) is expanded, as shown in FIG.
(19) The slit (18) between the horizontal piece (20a) and the vertical piece (20b) due to the deformation of the band-like part between (18).
) and a ribrus (21) having a mesh (20) consisting of
is obtained.

As shown in Fig. 4, the obtained replus (2
The horizontal piece (20a) branching from the vertical rib (19) of 1) has a root part (22) that is wide at the end and has great strength, and one edge of the horizontal piece (20a) branches from the vertical rib (19) of the slit (18).
Vertical rib (19) is formed by refraction of (8a) (18b)
), the bending and tensile stress is applied to the root part (22
) As a result, the root part (
22) The entire structure is curved and extends laterally, and no cracks occur at all. Further, when this rib brass (21) is bent toward the convex side of the vertical rib (19), the cuts made by both ends (18a) and (18b) of the slit (18) open to some extent, but the direction is not the same as that of the vertical rib (19). 19), so it is difficult to elongate as it deviates from the transverse direction of the vertical rib (
19) will not result in rupture.

In addition, in the above embodiment, three grooves (
16) is formed to divide the slit (18) into four, but the number of divisions can be changed in various ways, and it may be a continuous slit without division. Further, a roll mold can be used instead of a press mold to form the slit (18). Furthermore, the angle (θ) of both ends (18a) (18b) of the slit (18) with respect to the longitudinal direction of the thin plate is an acute angle, but especially 6
The angle is preferably 0° or less.

Effects of the Invention According to the method of the present invention, both ends of the convex slit formed by slitting are bent in a specific direction and within a predetermined angle range with respect to the longitudinal direction of the thin metal sheet. Ribrass with high strength that does not easily break the mesh or longitudinal ribs even when subjected to bending and tensile stress can be easily manufactured at low cost.

[Brief explanation of drawings]

Fig. 1 is a plan view of a press mold used in an embodiment of the method for manufacturing Ribrass according to the present invention, Fig. 2 is a plan view of a thin metal plate with slits formed in the same mold, and Fig. 3 is a plan view of the same method. FIG. 4 is an enlarged perspective view of the circle in FIG. 3, FIG. 5 is a plan view of a press mold used in a conventional method, and FIG. Fig. 7 is a plan view of a thin metal plate with slits formed using the same mold, Fig. 7 is a perspective view of the main part of librus obtained by the same conventional method, and Fig. 8 is a plan view of a thin metal plate with slits formed using another conventional method. The plan view and FIG. 9 are perspective views of the main parts of the librus obtained by the conventional method. (17)...Metal thin plate, (18)...Slit, (
18a)...End of top side, (18b)...End of hem, (19)...Vertical rib, (20)...Mesh, (
21)...Ribrass, (h)...Longitudinal direction of thin plate, (
θ)...Acute angle. that's all

Claims (1)

[Claims] After forming V-shaped slits in a band-shaped thin metal plate at regular intervals along the longitudinal direction of the thin plate, the non-slit areas continuous in the longitudinal direction of the thin plate are curved into a groove shape to form vertical ribs. In the manufacturing method of replus in which the thin plate is stretched in the width direction to form a mesh, both ends of each slit are turned inward on the top side of the V-shape and outward on the hem side, respectively, in the longitudinal direction of the thin plate. A method for producing a replus, which is characterized by forming a refracted shape within an acute angle range.