JP3313770B2 - Manufacturing method of stainless steel grating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a stainless steel grating used for attaching to a gutter or the like.

[0002]

2. Description of the Related Art As shown in FIG. 4, a stainless steel grating A has a side bar E connected to an edge of a lattice frame D formed by crossing a main bar B and a cross bar C.
It is mounted on receiving frames provided on both sides of the side groove, and is arranged in a large number of rows along the side groove, or is attached alone to the opening of the floor, and further, is appropriately combined, and There are various uses such as being used for landings on stairs.

[0003] The conventional method for manufacturing stainless steel grating A shown in FIGS. 4 and 5 includes the following steps. First, a plurality of connection holes b are formed in the main bar B by press working in accordance with the number of crossbars C. Here, the connecting hole b has a horizontal width equal to or larger than the width of the crossbar C and a vertical width equal to or smaller than the width. Further, a plurality of cuts c are formed in the upper edge of the cross bar C at predetermined intervals corresponding to the number of the main bars B by press working. Next, the required number of the main bars B are aligned with an appropriate jig, the cross bar C is laid down, and inserted into each of the connection holes b. Rotate and cut c
The upper end edge of the connection hole b is fitted into the inside. Then, it is welded and fixed at the position of the connection hole b. Such an operation is performed for each of the main bars B, so that the plurality of main bars B and the cross bars C are orthogonally formed to form the lattice frame D. Next, as shown in FIG. 4, side bars E and E are provided on the left and right edges of the lattice frame D ,
End bars F, F are brought into contact with the front and rear, and each edge is welded by means such as gas welding. Thus, stainless steel grating A is manufactured.

[0004]

In the above-mentioned conventional method for manufacturing the stainless steel grating A, it is necessary to form a connecting hole b in the main bar B and a cut c in the cross bar C, respectively. The assembling process such as inserting the crossbar C into the connection hole b and rotating it is troublesome and troublesome.

Therefore, as disclosed in Japanese Patent Publication No. 4-752, a circular insertion hole is formed in the main bar, a welding projection is formed in the circular insertion hole, and a concentrated current is caused to flow through the welding projection to perform projection. Manufacturing methods adapted for welding have been proposed. By the way, in such a means, in order to form a circular fitting hole provided with a welding projection, the mold becomes complicated and expensive, and furthermore, it is easy to wear at the location of the welding projection, has low durability, and does not last long. . SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a stainless steel grating that does not have the above-described problems and that can be efficiently assembled with the stainless steel grating.

[0006]

According to the present invention, there is provided an arcuate rim having an inner diameter substantially equal to the outer diameter of a cross bar having a circular cross section, and a straight side substantially equal to a tangent to an imaginary circle having the arc as a part. A plurality of circular insertion holes are formed, and a plurality of main bars having welding ridges formed at both end edges are arranged in parallel, and a cross bar is closely inserted into the circular insertion holes of each main bar aligned in the orthogonal direction. Then, the main bar and the crossbar are combined in a lattice shape, and the crossbar is brought into contact with the straight side of the circular insertion hole,
Further, at the position of the circular insertion hole, a voltage is applied between the main bar and the crossbar, a concentrated current is generated at a contact portion of the straight side with the crossbar, and the two bars are joined by projection welding to join the bars. The frame is manufactured, and then the side bar is pressed against the edge of the main bar of the lattice frame, and a voltage is applied between the welding ridge formed on the edge and the side bar to melt the ridge. A stainless steel grating, wherein the lattice frame and the side bar are joined by projection welding.

[0007]

According to this method, it is necessary to punch out a circular insertion hole having straight sides only in the main bar. This circular insertion hole has no projection formed on its inner periphery, and therefore, the structure of a die for punching this is simplified,
There are no excessive wear points, and the durability is good.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. As shown in FIG. 1, first, a circular insertion hole 1 is formed in the main bar B at equal intervals by a plurality of punching processes. The insertion hole 1 includes an arc edge x having an inner diameter substantially equal to the outer diameter of the cross bar C having a circular cross section, and a straight side y substantially equal to a tangent to an imaginary circle z having the arc edge x as a part. I have. This straight side y becomes a welding edge as described later.
In addition, since the circular insertion hole 1 has no convex portion, the structure of the mold for manufacturing the circular insertion hole 1 has a simple circular shape, and concentrated stress does not act on a part, the degree of wear is low, and the durability is good. .

As shown in FIG. 1, welding ridges 2 and 2 are formed at both ends of the main bar B.

A plurality of the main bars B are arranged and held in parallel, and the circular insertion holes 1 are aligned in front and rear, and as shown in FIG. Insert the crossbar C and assemble it in a grid. By inserting the crossbar C into the circular insertion hole 1, the crossbar C makes point contact with the straight side y of the circular insertion hole 1.

The cross bar C and the straight side y of the circular insertion hole 1 are held so as to make point contact with each other, and the main bar B is electrically grounded via a mount supporting the main bar B. When an AC power supply is connected by bringing the electrode bar 10 into contact with the cross bar C and an AC voltage of about 200 V is applied from the electrode bar at the position of the insertion hole 1, the cross bar C and the circular shape are formed in the effective voltage band of the cycle. A concentrated voltage is applied to a point contact portion of the insertion hole 1 with the straight side y, an excess current flows and melts, and projection welding is performed as shown in FIG.
Thereby, the crossbar C is resistance-welded in the insertion hole 1. Thus, the crossbar C is firmly connected to the main bar B, and the assembly of the lattice frame a is completed.

When the joining of the lattice frame a is completed, the lattice frame a
Is joined to a side bar E. That is, as shown in FIG. 3A, side bars E, E are arranged opposite to both ends of the lattice frame a, and the electrode rods 11 connected to the pressurized cylinders arranged on both sides thereof are connected to the cylinder rods. By extension, the side bar E is pressed against both end positions of the lattice frame a. The electrode rods 11 are arranged on the sides of the lattice frame a for each contact end of each main bar B, and are synchronized with the contact at a pressure contact position of the side bars E, E with the main bar B of about 210 V. About AC voltage is applied. By applying the voltage, a current flows from the side bar E to the ridge 2 of the main bar B. At this time, an excessive current flows through the ridge 2 to cause melting of the ridge 2, and the side bar E is resistance-welded to the edge of the main bar B of the lattice frame a as shown in FIG.

In this joined state, unlike the means of forming a ridge on the inner surface of the side bar E and performing resistance welding, the ridge does not appear in the assembled state and a good finish is obtained.

Thus, the side bars E are connected to both sides of the lattice frame c, and the production of the stainless steel grating A shown in FIG. 1 is completed.

[0015]

According to the present invention, a plurality of circular insertion holes 1 each having a straight side y serving as a welding edge are formed, and a plurality of main bars B having welding ridges 2 formed at both end edges are arranged in parallel. The crossbar C penetrates the circular insertion hole 1 of each main bar B aligned in the orthogonal direction, and the crossbar C on the straight side y of the circular insertion hole 1
The main bar B and the cross bar C are joined by projection welding to the contact portion between the two bars.
And the connection between the lattice frame a and the side bar E can be continuously performed only by resistance welding, so that the production efficiency of the stainless steel grating A can be significantly improved and the main bar B can be formed. Since the circular insertion hole 1 has a simple shape and has no projection, the structure of a die for punching the circular insertion hole 1 is simplified, and there are excellent effects such as no excessive abrasion and good durability.

[Brief description of the drawings]

FIG. 1 shows a main bar B showing a circular insertion hole 1 and a ridge 2
FIG.

FIG. 2 is a partial front view showing a welding process of a main bar B and a cross bar C;

FIG. 3 is a partial front view showing a welding step of a main bar B and a side bar E;

FIG. 4 is a plan view of a stainless steel grating A according to a conventional method.

FIG. 5 is a perspective view showing a connecting process of a main bar B and a cross bar C according to a conventional method.

[Explanation of symbols]

 Reference Signs List A stainless steel grating B main bar C cross bar D lattice frame E side bar 1 circular insertion hole 2 ridge x arc periphery y straight side

Claims (1)

(57) [Claims] 1. A plurality of circular fitting holes each having a circumference of an arc having an inner diameter substantially equal to the outer diameter of a cross bar having a circular cross section and a straight side substantially equal to a tangent line of an imaginary circle having the arc as a part. A plurality of main bars having welding ridges formed at both end edges are arranged side by side, and a cross bar is closely inserted into the circular insertion hole of each main bar aligned in the orthogonal direction to form a main bar and a cross bar. Are combined in a lattice pattern, and the crossbar is brought into contact with the straight side of the circular insertion hole. Further, at the position of the circular insertion hole, a voltage is applied between the main bar and the crossbar, and The two bars are joined by projection welding by generating a concentrated current in the contact portion to produce a lattice frame. Next, the side bar is pressed against the edge of the main bar of the lattice frame, and Between the welding ridge formed on the edge and the sidebar And pressure applied, method for producing a stainless steel grating, characterized in that joining the lattice frame and a side bar by projection welding by melting of the ridge portion.