JPH04752B2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to gratings, which are formed by bonding plate-shaped or rod-shaped metal members and forming them into a lattice shape, and are used as covers for grooves, manholes, sewage basins, etc. This relates to a molding method.

``Prior art'' In general, gratings, for example, in the case of a rectangular grating, two band-shaped end plates 1, which serve as frames on two sides, are placed opposite each other in the long side direction, as shown in Fig. 3. Between the end plates 1, two groups of bearing bars of the required pitch are arranged in parallel, and the inner surface of the end plate 1 and both end surfaces of the bearing bars 2 are individually welded, and at the middle of the bearing bars 2 arranged in parallel. , connecting bars 3, which are separate members, are arranged and coupled in parallel with the end plate 1 to form a lattice shape. The connecting structure of the connecting bar 3 is as shown in FIG. A horizontally elongated insertion window 5 is formed in the body, and the connecting bar 3 is flattened and inserted into the insertion window 5, rotated 90 degrees, and the bearing bar 2 is fitted into the fitting groove 4A4B to connect it. Alternatively, in the case of a bearing bar 2 having a T-shaped cross section, a spacer tube 6 is installed between adjacent bearing bars 2 as shown in FIG. The connecting bar 3 is inserted through the connecting hole 7 and connects the connecting bar 3 and two groups of bearing bars.

``Problems to be Solved by the Invention'' In the conventional grating shown in FIG. 3, after forming the fitting groove 4A4B of the connecting bar 3 and the insertion window 5 of the bearing bar 2, Since the connecting bars 3 are inserted and rotated and fitted, an increase in process and man-hours is unavoidable, and in the case shown in Figure 4, the work of attaching the spacer tubes 6 to the adjacent bearing bars 2 is extremely complicated. However, both have processing difficulties and the problem that the process of connecting the connecting bar 3 cannot be automated.

According to the forming means shown in the third and fourth figures above, the connecting bar 3 and the bearing bar 2 can be welded and fixed only every few pieces in practical terms (from the viewpoint of processing cost). There is a quality problem in that the fixing performance between the bearing bar 2 and the bearing bar 2 is poor.

An object of the present invention is to provide a new molding method that solves the problems of the prior art described above.

``Means for Solving the Problems'' The present invention achieves the above-mentioned objects by ``a group of bearing bars arranged in parallel at a required pitch, connecting connecting bars to form a lattice-like grating. At the same time as forming the hole-like insertion portion of the bar, a welding protrusion is formed on the inner edge of the hole-like insertion portion, and then, the hole-like insertion portion is provided with a welding protrusion. A grating characterized in that a connecting bar is inserted and attached, the welding protrusion and the connecting bar are brought into pressure contact, and a concentrated current is generated in the contact area to perform spot welding, thereby connecting and connecting the bearing bar and the connecting bar. The molding method.

"Operation" According to the above-described molding method of the present invention, when forming an insertion part by, for example, press working, a welding protrusion is simultaneously formed on the insertion part, and the connecting bar and the welding protrusion are pressed into contact with each other in an instant. Since spot welding can be performed, the construction method is simplified and made more efficient, and the process of connecting the bearing bar 2 and the connecting bar 3 can be automated.Furthermore, the bearing bar 2 and the connecting bar 3 can be individually welded. This has the effect of improving connection quality.

"Example" Hereinafter, a detailed explanation will be given based on an example. First, referring to FIG. 1 showing the first embodiment, the figure shows a grid in which a large number of bearing bars 2 each consisting of a flat bar with a rectangular cross section are arranged in parallel, and a rectangular connecting bar 3 is connected to the upper end of the bearing bars 2. This is an example in which the present invention is applied to molding of shaped gratings. That is, when the bearing bars 2 arranged in parallel at a required pitch are connected in a lattice shape using the connecting bars 3, cutout-shaped insertion portions are provided at required positions on the upper edge of the bearing bars 2, into which the connecting bars 3 are fitted from above. 8 is formed, and a welding protrusion 9 is formed at the bottom of the insertion portion 8 at the same time as the insertion portion 8 is formed.

This welding protrusion 9 is formed as a welding point when welding and joining the fitted connecting bars 3, and is formed and provided at the same time as the notch processing of the insertion portion 8 by pressing. In order to make the welding point effective, the welding protrusion 9 has a trapezoidal cross section, and the upper bottom surface 10, which is the top, continues in the direction of the pressing process. The width of the upper base 10 of the welding protrusion 8 in this embodiment is approximately 0.5 mm, and the width of the lower base 1 is approximately 0.5 mm.
The width of 1 is approximately 3.0mm and the height is 1.0mm.

The connecting bar 3 is inserted into the insertion portion 8 of the bearing bar 2 described above, and the lower surface of the connecting bar 3 is brought into contact with the upper bottom surface 10 of the welding protrusion 8.

After that, as shown in Fig. 1B, the bearing bar 2
At the same time, attach a clamp-shaped energizing terminal 13 to the
The energizing terminal 12 is pressed into contact with the upper surface of the connecting bar 3, and the connecting bar 3 and the bearing bar 2 into which the insertion portion 8 is inserted are pressed and clamped by the two energizing terminals 12 and 13. Electricity is applied between the current-carrying terminals 12 and 13 to spot-weld and connect the connecting bar 3 and the bearing bar 2.

At this time, a high current is applied for an extremely short time period of 1 to 2 cycles of the primary power supply for spot welding to achieve instant bonding.

Next, FIG. 2 shows a second embodiment of the present invention in which a connecting bar 3 is passed through and connected to the body of a bearing bar 2 having a T-shaped cross section. In the figure, a hole-shaped insertion portion 8 that passes through the connecting bar 3 of the tubular body is formed in the body of the bearing bar 2 at a predetermined position (in the middle position of the width), and an inner edge of the insertion portion 8 is formed. The same welding protrusion 9 as in the embodiment of FIG. 1 is simultaneously molded on the upper part of the holder. That is, the welding protrusion 9 is formed simultaneously with the drilling of the insertion part 8 using a press, and the connecting bar 3 is brought into contact with the upper bottom surface 10 of the insertion protrusion 9 and inserted.

Then, as in the embodiment shown in FIG.
A high current is instantaneously applied between the bearing bars 3 and 3 to weld the connecting bar 3 to the bearing bar 2 via the welding protrusion 9, thereby forming a connection between the two.

According to the above-described molding method of the present invention, the welding protrusion 9 is formed and provided on the insertion portion 8 of the bearing bar 2, and the top of the welding protrusion 9 and the connecting bar 3 are pressed into contact and spot welded. , insertion projection 9
A concentrated current is generated between the top of the bar 3 and the connecting bar 3, and the welding protrusion 9 is instantaneously melted to firmly weld the contact surfaces of the two.

Therefore, at the joint between the bearing bar 2 and the connecting bar 2, as shown in FIG. 1D and FIG. 2C, a thin layer 14 consisting of melted welding protrusions 9 is spread out and interposed to firmly connect the two. Fixed and bonded. Since the welding protrusion 9 is molded simultaneously with the insertion part 8, the welding protrusion 9
There is no need for a special forming means for this purpose, and bonding and forming can be accomplished by simply inserting the connecting bar 3 into the insertion portion 8, attaching the current-carrying terminal, and energizing it. Therefore, compared to the conventional means shown in the third and fourth figures, the steps and man-hours required for molding are significantly simplified and reduced. If the above-described method of connecting the bearing bars 2 and the connecting bars 3 is repeated in sequence, there is an advantage that the process of connecting a large number of bearing bar groups and the connecting bars 3 can be automated.

Furthermore, according to the molding method of the present invention, the bearing bar 2 and the connecting bar 3 of each set are individually spot welded, so there is no risk of welding distortion, the appearance is beautiful, and the bond is strong and stable. can improve grating quality.

"Effects of the Invention" As described above, the grating forming method of the present invention significantly improves the molding productivity of the joint molding of the bearing bar and the connecting bar, and also enables automation of the joint molding. This has many effects such as improving grating quality.

[Brief explanation of drawings]

Figure 1: Shows the molding method of the first embodiment of the present invention,
A is a perspective view thereof, B is a front view thereof, C is an enlarged front view of the insertion part of A, D is a front view showing the connected state, FIG. 2: shows the molding method of the second embodiment of the present invention, A is a perspective view thereof, B is a front view thereof, C is a front view showing the combined state, FIG. 3A: a perspective view showing a forming method by conventional means, FIG. 3B: a plan view of grating by conventional means, FIG. 4: A front view showing another molding method using conventional means. Main symbols: 1: End plate, 2: Bearing bar, 3: Connection bar, 8: Insertion part, 9: Welding protrusion, 10: Upper bottom surface of welding protrusion, 11: Lower bottom surface of welding protrusion, 12, 13: Current-carrying terminal.

Claims (1)

[Claims] 1. In forming a lattice-like grating by connecting connecting bars to a group of bearing bars arranged in parallel at a required pitch, a hole-like insertion portion for the connecting bars is formed in the bearing bar, and a hole-like insertion portion is formed in the bearing bar. At the same time as forming, a welding protrusion is provided on the inner edge of the hole-shaped insertion part, and then the connecting bar is inserted into the hole-shaped insertion part, and the welding protrusion and the connecting bar are pressed into contact with each other. A method for forming a grating, characterized in that the bearing bar and the connecting bar are connected and bonded by spot welding by generating a concentrated current at the contact area.