EP1039060A2

EP1039060A2 - Method and system for making prefabricated structural grid-like panels for making buildings

Info

Publication number: EP1039060A2
Application number: EP99110462A
Authority: EP
Inventors: Riccardo Frigerio
Original assignee: FROMA Srl
Current assignee: FROMA Srl
Priority date: 1999-03-25
Filing date: 1999-05-31
Publication date: 2000-09-27
Also published as: ITMI990620A1; IT1312155B1; EP1039060A3

Abstract

A system for making prefabricated structural grid-like panels for making buildings provides to use a pair of rollers which can be moved toward one another in order to press therebetween a preformed panel comprising a top net sheet and a bottom net sheet, therebetween an insulating material is arranged. As the net sheets are pressed, cross members of said sheets penetrate the insulating material to project from the opposite side thereof, thereby the cross members can be welded on wires of the corresponding net sheet.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a method and system for making prefabricated structural grid-like panels for making buildings.
The panels to which the invention relates, in particular, comprise a substantially sandwich construction, constituted by two adjoining grid-like elements therebetween a thermally or acoustically insulating material thickness or cushion is arranged.
Are already known structural grid-like panels in which the mutual positioning of the surface grid-like elements and the middle insulating material layer or thickness is performed by rectilinear wire cross-portions which are arranged at a slanted or perpendicular position in the interspace between the grid-like elements, by causing said wire cross-portions to pass through the layer of thickness of insulating material, to be cut according to a set length.
A main drawback of such a prior panel is constituted by the very complex method for making said panels, which provides to form the panel construction directly as the cross wires are entrained through the thickness of the insulating material. Thus, in such a method, it would be very difficult to hold the sheet nets properly located, with a consequent generation of a great unevenness in the arrangement of their facing surfaces. In particular, said sheet nets tend to be deformed as the cross wires are fed, and, consequently, the wires themselves are located in offset positions.
To the above it should be added that the wires, which are usually provided in a high number (i.e. twenty) are frequently offset as they are caused to pass through the thickness of the insulating material, mainly due to a resistance of said insulating material to the penetration and sliding of the wire, in combination with a poor strength of said wire against to the operating stresses. Accordingly, said wires tend to be deformed, thereby their end portions are frequently offset from a proper arrangement at the welding points, as defined by the positions of the electrodes of the welding grippers. Thus, the strength of the panel will be weakened, specifically at the unwelded portions.
Further welding defects can derive from the insulating material being removed from the wire end portions during the penetrating movements of the latter, entraining the insulating material to the electrodes of the welding grippers. In such a condition, the insulating material will prevent a proper weld current from passing through, thereby the cross stiffening elements cannot be properly welded to the panel nets.
In order to prevent this latter drawback from occurring, in the prior art the end portions of the wires entrained through the insulating material layer are frequently heated to facilitate the penetration of said wires while preventing them from changing their set entrainment paths. This heating operation, however, presents a further drawback of melting the insulating material on the wire passing therethrough, thereby said insulating material will be brought again in contact with the net welding electrodes.

SUMMARY OF THE INVENTION

Accordingly, the aim of the present invention is to provide a novel method and system for making prefabricated structural grid-like panels which method and system are much simpler and reliable than prior like methods and systems.
Within the scope of the above mentioned aim, a main object of the present invention is to provide such a method and system which are specifically designed to overcome the above mentioned drawbacks and, in particular, the drawback of an uneven welding of the cross members provided for cross connecting the mentioned net sheets.
A further object of the present invention is to provide such a method and system allowing to fully overcome any offsets of the panel stiffening cross-elements, as well as the insulating material entrainment phenomena, susceptible to negatively affect a proper operation of the welding gripper electrodes.
Yet another object of the present invention is to provide such a method and system adapted to make a grid-like panel devoid of any defects and having an even and homogeneous construction.
The above aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by the inventive method and system, as respectively defined in the independent claims 1 and 8.
Preferred embodiments of the invention being defined in the depending claims.
With respect to the prior art in this field, the method and system according to the invention are much more simple and reliable.
In fact, and more specifically, the pre-arrangement of a preformed panel and the welding thereof at an operating stage following the preforming stage, would allow to fully eliminate any possible portions of insulating material susceptible to be entrained by the panel stiffening cross-elements caused to pass through the insulating material.
Moreover, the assembling of the panel including stiffening cross-elements having stiffening properties much greater than those of simple rectilinear wires, would allow the net welding grippers to be easily centered, thereby overcoming any drawbacks related to an uneven welding of the net cross coupling elements.
As stated, the panel made by the method and system according to the present invention is efficiently devoid of any unevenness in the arrangement of the stiffening cross-elements, is provided with very even net welding spots and, moreover, is devoid of any constructional defects.
In particular, the invention would allow to easily make a standard panel having a width of 1,200 mm, and including 100 stiffening cross-elements for each m² of panel, by using, instead of 40 wire rolls and 20 welding units, as are necessary in the prior art, only 25 wire rolls and 10 welding units.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and further features and advantages of the present invention will become more apparent hereinafter, from the following disclosure of a preferred embodiment of the inventive method and system, with reference to the accompanying drawings, in which a preferred embodiment of the invention is illustrated by way of a not limitative example thereof.
In the drawings:
Figure 1 is a side view illustrating a net forming station included in the system according to the invention;
Figure 2 illustrates a detail A of the forming station of Figure 1;
Figure 3 illustrates the detail A of Figure 2 by a schematic view taken substantially along a longitudinal axis;
Figure 4 is a top plan view illustrating the net forming station of Figure 1;
Figure 5 is a side view illustrating the assembling stations for assembling the panels, as provided in the system according to the invention;
Figure 6 is a detail view illustrating a detail B of Figure 5;
Figure 7 is a front detail view illustrating a detail C of Figure 5;
Figure 8 is a top plan view illustrating the panel assembling stations of Figure 5;
Figure 9 is a detail view illustrating a detail of a unit for cutting the net sheet elements; and
Figures 10 to 20 illustrate several operating steps of the inventive method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The system shown in Figure 1 comprises a plurality of reels or bobbins 11 for supplying a corresponding number of longitudinal wires 1, to be used for making the panel forming nets.
A welding station 12 is provided for welding the longitudinal wires 1, the cross-wires 2 supplied either by a reel 13 (Figure 4) or a bar loader 14 (Figure 1). Thus, a continuous net 3 is obtained, which is conveyed, in the direction of the arrow F2 of Figure 1, by a conveyor or feeding device 15.
This feeding device 15, in particular, drives the net 3 to a forming station 16 for forming V-shaped cross-elements 5, specifically designed for cross stiffenings the panel being formed. The cross-elements 5 are made starting from corresponding wires 17, also supplied from the reels 11, and driven toward the station 16 and cut by a cutter 18 (Figure 2), into rectilinear wire portions 4. Said wire portions 4 being successively bent in a bending station 16, by punch element 19 caused to be lowered on the wire portion 4, as indicated by the arrow F1 of Figure 2, and being counter-biassed by a tool 20 reproducing the V-shape to be imparted to the cross-element 5.
The open end portions of the cross-element 5 are then caused to locate adjoining a corresponding longitudinal wire 1, to be welded on the latter by welding grippers 21 (see Figures 2 and 3). The system is supplied in the direction of the arrow F4 of Figures 5 and 6. In the shown embodiment the rollers 27 is accordingly rotatably driven in the clockwise direction, whereas the roller 28 is anticlockwise driven (see the arrows F5 and F6 of Figure 6, respectively). Advantageously, the cross-elements 5 are welded on the wires 1, in a position thereof bridging the crossings or "knots" with the cross wires 2, at an offset position from the net 3 longitudinal axis 25 (Figure 4).
The welding grippers 21 can moreover be driven either vertically toward or away from the wires 1, thereby allowing to perform a quick and easy welding operation while disengaging the net being formed to allow it to be driven step-by-step in the direction of the arrow F2.
At the outlet of the forming station 16, the net 3, including the cross-element 5 all arranged on a same side or face of said net, will be laterally trimmed by two cutting units 22 (Figure 1), to remove any cross wire 2 projecting portions.
After this cutting or trimming operation, from the continuous net 3, sheet elements 6 are cut, by a further cutter 23 (see also Figure 9). The reference number 24 of Figure 1 illustrates a automatic stacking device for automatically stacking the net sheets 6 and driving said stacked net sheets to the assembling station shown in Figure 5.
Said assembly station, in particular, is loaded by a bottom horizontal sheet 62 having the stiffening cross-elements 5 thereof facing upwardly, with a plate or layer of insulating material 7 arranged above the apex portions 31 of the cross-elements 5 of said net sheet 62, and with a top horizontal sheet 61 reversely arranged on the insulating layer 7, thereby arranging the stiffening cross-elements 5 thereof with the apex portions 31 abutting against the surface of said insulating layer 7 (see Figure 15).
Owing to the offset arrangement of the stiffening cross-elements 5 from the longitudinal axis 25 of said net sheets 6 (Figures 4 and 15), the reversing of the top net sheet 61 on the bottom net sheet 62 will cause an offset between the vertical projections of the respective cross-elements 5, which will be consequently arranged with an alternating arrangement, with respect to one another, in the cross direction of the panel (Figure 15).
Then (Figure 6), guiding elements 26 will drive the thus obtained assembly to an inter-space or gap between a pair of rollers 27 and 28, which can be vertically driven to be mutually moved toward one another or away from one another (see the arrows F3 of Figure 6).
As shown, said rollers 27, 28 are moreover provided with toothed inserts 29, provided for engaging the net sheets 61 and 62.
At a starting step, the rollers 27 and 28 are arranged spaced from one another, thereby allowing the sheets 61, 62 and layer 7 to be introduced into their gap 30. Then, said rollers will be driven toward one another (Figure 6), thereby also causing the net sheets 61 and 62 to be mutually driven toward one another. Thus, the cross-elements 5 will be pressed so as to cause them to penetrate the insulating material 7 so as to bring the apex portions 31 of the cross-elements 5 of the bottom net sheet 62 to project from the top surface of said layer, at the height of a respective longitudinal wire 1 of the top net sheet 61 (Figure 20).
Likewise, the pressing by the rollers 27, 28 will cause the apex portions 31 of the cross-elements of the top net sheet 61 to be downward driven, thereby projecting from the bottom side of the insulating layer 7, and at the longitudinal wires 1 of the net sheet 62.
Thus, the rotary driving toward one another of said rollers 27, 28 will provide a preformed panel, having a substantially sandwich construction, and comprising the opposite net sheets 61 and 62, provided with respective stiffening cross-elements 5 fully entrained through the thickness of the insulating material or layer 7, so as to project therefrom for an amount required to engage the wires of the other net sheet.
Two guides 32 arranged at the outlet of said rollers 27, 28 will cause the inserts 38 to be disengaged from the net sheets and the preformed panel to be withdrawn from said rollers, a conveyor 33 conveying said preformed panel toward the welding station 34 (see the detail C of Figure 5 and Figure 7).
The welding station 34, as shown, is provided with welding grippers 35, arranged on both sides of the panel and designed for welding the apex portions 31 of the stiffening cross-elements 5 on the longitudinal wire 1 of the net sheet thereagainst said welding grippers are caused to abut. The welding grippers 35, as the mentioned grippers 21, can be vertically driven as shown by the arrows F7 and F8 of Figure 5.
Thus, a structural grid-like panel 37, in a finished, welded and even arrangement is provided, said panel being driven step-by-step by a driving device 36 (Figure 5). In such a condition, the panel 37 can be manually removed, or it can be automatically removed by an automatic removing and stacking system 38 (Figure 8).
The method carried out in the above disclosed system essentially comprises the following steps:

Figure 10

A plurality of longitudinal wires 1 are supplied, and then cross-wires 2 are welded thereon, thereby forming a continuous net 3.

Figure 11

Starting from a corresponding number of wires 17, rectilinear wire portions 4 are cut therefrom, to be bent so as to form V-shape cross-elements 5. Then, said cross-elements 5 are welded on the longitudinal wires 1 of the net 3 bridging the cross-points with the cross wires 2 and being offset from the longitudinal axis 25 of said net. Finally, the welded end portions of the cross-wires 2 are trimmed.

Figure 12

Then, the net 3 is cut into net sheets 6, having a set length, and bearing thereon the stiffening cross-elements 5 welded on the wires 1, on a same side of said sheets.

Figure 13

The net sheets 6 are stacked with a separated arrangement.

Figures 14 and 15

A sandwich arrangement is then formed, which comprises by arranging an insulating material layer 7 between two sheets 6, i.e. a top sheet 61 and a bottom sheet 62, each of one is reversed with respect to the other. In such a mutually reversed arrangement of the net sheets, and owing to the cross offset of the respective cross-elements 5, the latter will be located with an offset arrangement on the panel being formed (Figure 15).

Figure 16

The thus assembled construction is driven into the gap between two opposite rollers 27 and 28 which are held in a mutually spaced condition.

Figure 17

The rollers 27, 28 are driven toward one another and against the end portions of the net sheets 61, 62 being fed between the rollers. This driving of said rollers will cause the front end portions of the net sheets to be abutted against the insulating material or layer 7 with a consequent pressing and penetration of the corresponding cross-elements 5 through the thickness of the insulating layer or material.

Figure 18

Then, the rollers 27 and 28 are rotatively driven in order to preform the overall panel, which is then fed into the interspace or gap between said rollers. This operation is carried out simultaneously with a calibration or setting of the spacing of the net sheets 61 and 62, thereby causing the apex portions 31 of the respective cross-elements 5 to perforate the thickness of the insulating material, to project from the opposite net, at a position suitable for welding (Figure 20).

Figure 19

Then, the apex portions 31 of the V-shape cross-elements 5 are welded to the longitudinal wires of the opposite net.

Figure 20

The finished panel 37 is finally unloaded from the machine.
According to a main feature of the present invention, the welding of the apex portions 31 of the cross-elements 5 of said panels (Figure 19) is carried out in a separated unit which is separated from that making the preformed panel (Figure 17). Thus, possible insulating material traces 7 entrained by the cross-elements 5 can be removed before welding.
The invention, as disclosed and illustrated, is susceptible to several modifications and variations all of which will come within the spirit and scope of the invention.
Thus, for example, the panel making method could also provide to supply two continuous nets 6, instead of two separated net sheets 61 and 62. In this case, the method would cause the two nets 6 to continuously pass, in a mutual overlapped arrangement, respectively above and under the insulating material layers 7, between the rollers 27 and 28. Said rollers, in particular, could also be replaced by other suitable pressing elements, of a not rotary type (for example movable plates). According such a modified embodiment, moreover, the cutting of the nets to provide the panels having a set length, would be performed after the welding of the nets, at their cross-elements. In this connection it should be moreover pointed out that all the disclosed apparatus could be replaced by other devices having a like operation, and specifically designed to provide a panel having the claimed features.

Claims

A method for making prefabricated structural grid-like panels for making buildings, said panels comprising a framework including two facing metal nets arranged spaced from one another and coupled to one another by V-shape cross-elements (5), the base end portions of said cross-elements being welded to the wires of a corresponding net sheets and an apex portion (31) thereof being welded to the wires of the opposite net sheet, at least an insulating material layer (7) being arranged between said net sheets (61, 62), characterized in that said method comprises the step of preforming a preformed grid-like panel and welding said metal nets at said apex portions (31) of said cross-elements (5).
A method according to Claim 1, characterized in that said method comprises the step of arranging said insulating material layer (7) between a bottom metal net and a top metal net reversed with respect to said bottom metal net, the cross-elements (5) of each said net having their apex portions (31) abutting against a corresponding surface of said layer (7) and at a cross position offset from the cross-elements (5) of the other opposite metal net.
A method according to Claim 2, characterized in that said method comprises moreover the step of driving toward one another said metal nets by pressing said metal nets, said pressing causing said cross-elements (5) to pass through said insulating material layer (7) and causing said apex portions (31) of said cross-elements (5) to exit the bottom metal net from the top surface of said layer (7), and further causing said apex portions (31) of said cross-elements (5) of said top metal net to exit the bottom surface of said insulating material layer (7).
A method according to Claim 3, characterized in that said method comprises moreover the step of welding said apex portions (31) of said cross-elements (5) on the respective metal net in the projecting direction of said apex portions, and cutting the nets to provide a panel having a set length.
A method according to one or more of the preceding claims, characterized in that said method comprises moreover the step of cutting and bending to a V-shape rectilinear wire portions (4), to provide said cross-elements (5).
A method according to Claims 4 or 5, characterized in that said method further comprises the step of welding the base end portions of said cross-elements (5) on the longitudinal wires (1) of said metal nets, bridging the cross-points with the cross wires (2) and at a position offset from the longitudinal axis of said nets.
A method according to one or more of the preceding claims, characterized in that said method comprises the steps of:

supplying a plurality of longitudinal wires (1) and welding thereon cross-wires (2) thereby providing a continuous net (3);

welding, on said longitudinal wires (1), a plurality of V-shape cross-elements (5);

cutting said net (3) into net sheets (6) having a set length and provided with said cross-elements (5) all arranged on a same surface of said sheets (6) and

arranging an insulating material layer (7) between a bottom net sheet (62) and a top net sheet (61).
A system for making prefabricated structural grid-like panels for making buildings by a method according to one or more of the preceding claims, characterized in that said system comprises preforming means for preforming a preformed grid-like panel and for welding said metal nets at said apex portions (31) of said cross-elements (5).
A system according to Claim 8, characterized in that said forming means comprise:

a cross-element forming station (16) for forming said cross-elements (5) and welding base end portions of said cross-elements (5) on the wires of the metal nets forming said panel;

a loading station for loading an insulating material layer (7) between said metal nets, the apex portions (31) of said cross-elements (5) being oriented toward respective surfaces of said insulating material layer (7) and at offset positions on the cross plane of said panel;

a driving station for mutually driving said nets toward one another, by pressing said nets against said insulating material layer (7), thereby causing the apex portions (31) of said cross-elements (5) to pass through said insulating material layer (7), to project from a respective opposite surface of said panel; and

a welding station (34) for welding said apex portions (31) of said cross-elements of a net on the corresponding wires of the opposite net, above a surface of the insulating material layer (7) supporting it.
A system according to Claim 9, characterized in that said forming station (16) comprises:

cutters (18) for cutting wire portions (4) from corresponding rectilinear wires (17);

punch (19) and die (20) units cooperating for bending said wire portions (4) to form V-shape cross-elements (5)
and

welding grippers (21) for welding said cross-elements (5) to respective wires of said metal net, said welding grippers being provided with driving means for driving said welding grippers toward and away from said net.
A system according to Claim 9, characterized in that said driving station, provided for pressing said metal nets against said insulating material layer (7), comprises a first pressing element operating on the top net of said panel and a second pressing element, opposite to the first pressing element, operating on the bottom net, said first and second pressing elements including driving means for driving toward one another and away from one another said nets with respect to the plane of said panel.
A system according to Claim 11, characterized in that said first and second pressing elements comprise pressing rollers (27, 28) provided, on an outer surface thereof, with a plurality of toothed inserts (29) facilitating the gripping of said pressing rollers on said panel nets, said pressing station being moreover provided with guides (26, 32) for guiding said panel upstream and downstream of said pressing rollers (27, 28).
A system according to Claim 9, characterized in that said welding station (34) is provided with welding grippers (35) for welding said apex portions (31) of said cross-elements (5) of a net on the wires of the opposite net, further driving means for driving said grippers (35) in a cross direction of said panel being moreover provided.
A system according to one or more of the preceding claims, characterized in that said system comprises moreover:

a plurality of supplying reels (11) for supplying said longitudinal wires (1);

a bobbin (13) or a bar loader (14) for supplying a wire (2) transversely of said longitudinal wires (1);

a wire welding station (12) for welding said wires (1, 2) thereby providing a continuous net (3);

a net feeding device (15) for feeding said net;

a cutter (22) for cutting said wire (2) on said net (3);

a further cutter for cutting the continuous welded construction, thereby providing individual panels, or a cutting unit (23) for cutting said continuous net (3) into net sheets (6) having a set length;
and

a preformed panel conveyor (33) for conveying the preformed panel from the outlet of said pressing rollers (27, 28) as well as a finished panel feeding device (37).
A system according to Claim 14, characterized in that said system comprises moreover an automatic stacking device (24) for stacking said net sheets (6) and an automatic taking device (38) for automatically removing the finished panels (37).
A system according to one or more of the preceding claims, for making a standard panel having a width of 1,200 mm and provided with 100 cross-elements (5) for each m² of panel surface, characterized in that said system comprises 25 wire (1, 2) supplying reels and 10 net welding grippers (35).
A prefabricated structural grid-like panel for making buildings, characterized in that said panel is made by a method and a system according to one or more of the preceding claims.