JPH0149864B2 - - Google Patents

Abstract

The invention discloses a method of forming gratings suitable for use as walkways etc. The method includes the steps of forming transverse bearer bars (1) from strips of flat plate by punching a series of transverse slots across the central axis of each plate, then folding the plates to form U-sections with the slots located in the apices of the U-sections. Longitudinal bars, which are lengths of flat bar, are then inserted as tight press-fits into the slots, and the undersides of the longitudinal bars are deformed laterally between the legs of each U-section to prevent their removal from the slots. A strong lightweight grating results.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a floor grid suitable for supporting substantial loads off the ground and to a method for making the same, and in particular to floor grids extending at right angles to each other to form a load-bearing grid array. It concerns a type of grid having two sets of parallel bars. Such grids are commonly used in elevated passageways and the like.

In this specification, the two sets of bars are referred to as vertical bars and horizontal bars, respectively, but this does not limit the direction in which either set of bars extends within the assembled lattice.

It has already been proposed to use an inverted U-shaped member as the horizontal bar and to cut a slot in the apex of these horizontal bars to accommodate the vertical bar section (U.S. Pat. No. 1,620,846).
(see issue). In the '846 patent, the preferred shape of the vertical bars is square. According to this US patent:
After a series of horizontal bars are arranged in parallel with their slots aligned, the vertical bars are loosely dropped into the slots to form a grid. Make these slots deep enough to accommodate the full height of the vertical bar.

Placing the vertical bar in position within the slot and then deforming the vertical bar outward in the area between the legs of the U-shaped horizontal bar to prevent the vertical bar from exiting the slot. .
The horizontal bar is also deformed above the vertical bar to further ensure that the vertical bar does not slip out of the slot.

There are a number of problems associated with making grids of the type disclosed in US Pat. No. 1,620,846. In this patent, an inverted U-shaped member is formed by forcing the legs of the chevron members closer together. Most standard angle-shaped members available have considerable strength;
This task is not easily accomplished. This difficulty is increased because standard angle members have a finite radius or radius in their fillets, and this radius provides some resistance to bending the legs of the member closer together.

Another problem arises when slotting the apex of the cross member. US Pat. No. 1,620,846 proposes providing the slots by lateral punching or cutting. It is clear that the fillet of the chevron member resists this operation as well. The inherent properties of the angle members make the punching operation at the apex a difficult task.

Also, the vertical bar is deformed by a press operation. The bed plate of the press used is formed in such a way that the crossbars are deformed in the area of the edges of the transverse holes, and these edges overlap the longitudinal bars accommodated in the slots. However, such deformation has the effect of reducing the compressive strength of the upper edge of the crossbar. Furthermore, the fact that the entire height of the vertical bar is accommodated within the slot formed in the crossbar means that the uppermost edge of the steel crossbar cannot carry any compressive loads. This is because the material is not continuous above the level of the vertical bars.

Another drawback of the grid described in US Pat. No. 1,620,846 is the protection of the grid against corrosion once manufactured. If plating or painting operations are attempted, sharp curves should be avoided to ensure uniform coating. The deformation operation employed in the grid shown in this patent produces sharp edges on the sides of the slots, thus making it difficult to apply the necessary coating to these critical areas of the steel to protect the grid. Make it.

Nevertheless, the use of U-shaped cross members has been shown to have certain benefits in terms of weight savings. SUMMARY OF THE INVENTION It is therefore an object of the present invention to eliminate the above-mentioned drawbacks of known gratings and to provide a method for manufacturing gratings employing such elements.

The method of the present invention comprises a plurality of inverted U-shaped horizontal pillow bars and a plurality of pillow bars that are fitted into slots formed at the apex of the U-shaped pillow bars and are deformed within an area within the U-shaped portion. In manufacturing a floor lattice comprising longitudinal bars, a flat plate is bent to form said horizontal pillow bars, and then said longitudinal bars in an area on the outside and in an area on the inside of said U-shaped part. The vertical bars are formed by deforming the vertical bar material without cutting so that the heights of the vertical bars are substantially the same.

Preferably, the vertical bar is press fit into the slot.

A slot can be formed at the apex of the crossbar by punching before folding the plate.

The vertical bars are deformed by applying a lateral force to the material of each vertical bar in an area within the U-shaped section, creating a bulge on one side of the vertical bar's plane.

Advantageously, a press head having an effective width greater than the spacing apart between the longitudinal bars is forced between the longitudinal bars to simultaneously deform adjacent longitudinal bars within each U-shaped section.

The floor lattice of the present invention includes a plurality of inverted U-shaped horizontal pillow bars, and a plurality of horizontal pillow bars that are fitted into slots formed at the apexes of the U-shaped pillow bars and deform within an area within the U-shaped portion. in the floor lattice comprising vertical bars, the horizontal pillow bars are formed by bending a flat plate;
It is characterized in that the vertical bar material is deformed without cutting so that the height of the vertical bar is approximately the same in the area on the outside of the U-shaped part and in the area on the inside of the U-shaped part. do.

A portion of each vertical bar projects above the level of the apex of the horizontal bar.

The invention will be explained with reference to the drawings.

The portion of the finished lattice shown in FIG. 1 consists of horizontal pillow bars 1 and vertical bars 2. As clearly shown in FIGS. 3 and 5, each side pillow bar has a U-shaped cross section. This U-shape is actually similar to a V-shape, but since the apex portion of the cross section always has a certain radius, this cross section is referred to as a U-shape. Furthermore, it is preferable to have a slightly rounded apex. This is because it is obvious that if the apex of the horizontal pillow bar 1 is too sharp, it will cause discomfort to the feet of the person walking on the grid.

It is also clear from the drawing that the vertical bar 2 has an uneven upper edge in the style of a castle. This helps prevent slipping on the grate. This type of grid is often used at considerable heights;
It is clear that if a person walks on this grid and slips, the consequences will be dire.

Form the horizontal pillow bar 1 as follows. A strip of flat plate is passed under a punch and the punch is activated to punch a series of spaced transverse slots 5 from the plates across the central axis of the plates. FIG. 4 shows such a board after the punching operation.

This plate is then bent around its central axis into the shape shown in FIG. The resulting U-shaped cross-section member has a series of spaced slots 5 along its apex.

The horizontal pillow bars 1 are then arranged in spaced apart parallel relationship so that the corresponding upwardly oriented slots of each of the horizontal pillow bars 1 are aligned with each other, and the vertical bars 2 are received in the slots. to form a grid.

The vertical bar 2 is a long flat bar. Before inserting the rod into the slot, make a castle-like unevenness along the upper edge of the rod.
This lattice allows the user's feet to be held better.

Next, each vertical bar 2 is forced into one row of the arranged slots so as to form a tight press fit. When folding the plates to form the horizontal pillow bars 1, the slots are dimensioned so that they are not deep enough to completely accommodate the vertical bars 2. As is clear from FIG. 3, the uneven portion of each vertical bar is made to protrude above the level of the apex of the horizontal pillow bar. As the vertical bars are forced into the slots in the horizontal pillow bars, this tight fit results in compressive forces on the upper edges of the steel horizontal pillow bars. In other words, this upper edge is in a state where "prestress" is applied. The horizontal pillow bar is slightly warped. This obviously acts to increase the overall strength of the assembled grid.
Compared to the grid disclosed in U.S. Pat. No. 1,620,846,
The continuousness of the material at the level of the apex of the cross pillow bars of the present invention increases the compressive strength along the upper edge of the cross pillow bars, rather than the lack of continuity of the material as in the above-mentioned US patents. I understand.

Once all the vertical bars have been pushed into the slots, the lower portions of these vertical bars are deformed to prevent them from becoming dislodged from the slots. As shown in FIG. 2, the vertical bars are deformed and bulged laterally (see numerals 3 and 4).
In practice, a single pressure head with an effective thickness greater than the spacing of the vertical bars acts between a pair of adjacent vertical bars in the space between the legs of each U-shaped, pushing the vertical bars in both directions. Inflate. In view of the speed and simplicity of the deformation operation, it is preferred to deform the vertical bars between the legs of each horizontal pillow bar in order to provide greater rigidity to the overall structure.

It has been found that the gratings produced by the method of the invention are approximately 30% lighter in weight than gratings of comparable strength. This is mainly due to the way the horizontal pillow bars are formed. The appropriate thickness of the flat plate used for the horizontal pillow bars is 3 mm, which is suitable for most uses. A flat plate of this thickness is not very heavy and easy to punch and handle.

During actual manufacturing, it was found that it was necessary to bend the legs of the horizontal pillow bars so that they were almost parallel to each other. If they are made parallel like this, lumps of coal etc. will fall freely between the pillow bars without becoming clogged. If a horizontal sleeper bar is made from a rectangular steel material, that is, an angle iron, as shown in U.S. Patent No. 1,620,846, it is difficult to bend the legs of the angle iron so that they approach each other. It is obvious that it is difficult to make the legs parallel.

The application of a protective coating to the finished grid is also much better than that of the prior art grid of the US patent. Since no creasing operations are performed on the apex of the sleeper bar, no sharp edges are created, which allows for a very uniform coating, such as a very uniform coating of zinc by galvanizing. The tight fit in the slots reduces the likelihood of relative movement between the two sets of horizontal pillow bars and longitudinal bars, resulting in reduced wear between the bars and damage to the applied coating. . A further readily discernible advantage of the present invention over the method known in the US patent lies in the punching operation for forming the slot at the apex of the cross pillow bar. It is clear that it is easier to punch a slot out of a flat plate than to punch or cut out a slot laterally from the apex of the angle iron.

Furthermore, the invention is applicable to grids with almost any span. When using shaped steel, the designer is limited by the available square cross-sections. When attempting to increase the size of the square timber, the difficulty in manufacturing increases accordingly. A lattice constructed according to the invention can optionally be designed to suit a wide range of spans, for example by increasing or decreasing the height of the legs of the side sleepers.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a lattice constructed according to the invention;
Figure 2 is a bottom view of the grid shown in Figure 1;
The figure is a side view of the lattice shown in Figure 1, Figure 4 is a plan view of the plate after punching out slots across the center axis of the plate, and Figure 5 is a view of the plate folded along the center axis after punching. FIG. 3 is a side view of the ivy horizontal pillow bar and the vertical bar having a castellated pattern along its upper end before being inserted into the slot of the horizontal pillow bar; 1...Horizontal pillow bar, 2...Vertical bar, 5...Slot hole.

Claims (1)

[Scope of Claims] 1. A plurality of inverted U-shaped horizontal pillow bars, which are fitted into slots formed at the apex of the U-shaped pillow bars and deformed within an area within the U-shaped portion. In a floor lattice comprising a plurality of vertical bars, the horizontal pillow bars are formed by bending a flat plate, and the vertical bars are arranged in an area outside the U-shaped portion and in an area inside the U-shaped portion. A floor lattice characterized in that the vertical bar material is deformed without cutting so that the heights are substantially the same. 2. The grid according to claim 1, wherein the vertical bars are press-fitted into the slots. 3. Claim 1 or 2, wherein each of the vertical bars has a bulge formed on one side of the plane of the vertical bar within an area within the U-shaped horizontal pillow bar. A lattice as described in any one of the sections. 4. A grid according to claim 3, characterized in that adjacent pairs of said vertical bars have oppositely directed bulges formed by a single pressing operation. 5 a plurality of inverted U-shaped horizontal pillow bars and a plurality of vertical bars that fit into slots formed at the apex of the U-shaped pillow bars and deform within an area within the U-shaped portion; In manufacturing a floor lattice comprising: bending a flat plate to form the horizontal pillow bars, and then determining the height of the vertical bars in the area outside and in the area inside the U-shaped part; A manufacturing method characterized in that the vertical bars are formed by deforming the vertical bar material without cutting so that the vertical bars are substantially the same. 6. The manufacturing method according to claim 5, wherein the vertical bar is press-fitted into the slot. 7. The manufacturing method according to claim 5 or 6, wherein the slot is formed at the apex of the horizontal pillow bar by punching before bending the flat plate. 8 deforming said longitudinal bars by applying a lateral force to the material of each said longitudinal bar in an area within said U-shaped portion, creating a bulge on one side of the plane of said longitudinal bar; Claim 5 characterized by
The manufacturing method according to any one of Items 7 to 7. 9 A patent characterized in that a press head having an effective width greater than the spacing between the vertical bars is forced between the vertical bars to simultaneously deform adjacent vertical bars in each U-shaped section. The manufacturing method according to claim 8. 10. The slot hole is formed so that when the vertical bar is accommodated in the groove structure, a portion of the vertical bar projects above the level of the apex of the horizontal pillow bar. The manufacturing method according to any one of the ranges 5 to 9.