ZA200602303B - Method and welding machine for production of mesh products - Google Patents

Description

® 1 PCT/AT2005/000253 ®

Method and welding machine for production of mesh products

The invention relates to a method for producing mesh products from groups of perpendicularly intersecting longitudinal and transverse elements that are welded together at the intersection points by the electric resistance welding method. The invention also relates to a welding machine operating according . to the electric resistance welding method, comprising a device for the transverse distribution of the longitudinal elements, a device for advancing the longitudinal elements in the longitudinal element feeding direction along a horizontal longitudinal element feeding plane and for introducing the longitu- dinal elements into the welding machine, a device for the transverse conveying of cut-to-length transverse elements into the area of the longitudinal element feeding plane, a device for feeding the transverse elements into the welding line of the welding machine extending transversely to the longitudinal element feeding direction, a device for tautening the transverse elements, several welding units arranged in a row transversely to the longitudinal element feeding direction, each of which consists of an upper and a lower welding head, and a conveying device that can be coupled to the welding units for shifting and positioning the welding units transversely to the longitudinal element feeding direction.

From AT-B-404910 a plant is known for feeding longitudinal elements to a welding machine for producing meshes from perpendicularly intersecting longitudinal and transverse wires that are welded together at the intersection points. Cut-to-length longitudinal elements are either first separated in a distributing device and then transferred to a delivering device, or are fed to the delivering device already separated. The delivering device delivers the longitudinal elements separated and the one after the other to a transverse

® 2 PCT/AT2005/000253 conveying device, which with the aid of conveyor chains conveys the longitudinal elements transversely to the longitudinal direction into the longitudinal element feeding plane of the welding machine, wherein by suitable control of the delivering device and the conveyor chains of the transverse conveying device, the longitudinal elements are placed on the conveyor chains approximately in accordance with the desired spacing between the longitudinal elements, the so-called longitudinal element pitch, in the mesh product to be produced. With the aid of several raisable and lowerable lifting-out elements the longitudinal elements are lifted out of the conveyor chains and gripped by several raisable and lowerable gripping tongs arranged above the conveyor chains, wherein the lifting-out elements and the gripping tongs are each shifted so far transversely to the production direction of the welding machine that they are aligned with the positions of the longitudinal elements in the to be produced mesh product. The gripping tongs transfer the longitudinal elements to a push-in carriage, which pushes the longitudinal elements into the welding machine. This plant has the disadvantage that longitudinal elements that have already been delivered must be moved sideways during the transverse distribution, so that an unintentional shifting of the longitudinal elements may occur. The known -plant furthermore has the disadvantage that technically complicated devices are required to lift the longitudinal elements out of the transverse conveying direction and bring them into the exact longitudinal element positions. With the gripping tongs used here the taking over, especially in the case of long, thin longitudinal elements, is very susceptible to problems and often leads to misgripping.

From EP-B1-399 996 a welding machine is known for producing meshes from perpendicularly intersecting longitudinal and transverse wires that are welded together at the crossing points. With this machine two material strands serving

® 3 PCT/AT2005/000253 _ as transverse wires are fed laterally to the welding machine along two shoot-in lines. Two transverse wires are simultaneously separated from these material strands and removed from the two shoot-in lines by two feeder arms arranged outside the outermost longitudinal wires and fed into the welding line of the welding machine. This feeding movement is executed by a feeder carrier which extends over the entire width of the welding machine and carries the feeder arms. For pre-tautening the two transverse wires, at least one of the feeder ) arms can be moved relative to the other feeder arm by means of a power drive with adjustable tautening force. Furthermore, at least one of the feeder arms is arranged on the feeder carrier shiftable relative to the other feeder arm for the positioning along the welding line. This welding machine has the disadvantage that the transverse wires are fed-in laterally in their longitudinal direction, so that it is not possible to position the transverse wires along the welding line in any one position one chooses.

The object of the invention is to avoid the described disadvantages of the known devices and to provide a method and device of the type mentioned at the outset, which permit the producing of a mesh product that has any selectable longitudinal and transverse element pitches, wherein the mesh product is positioned in a selectable place inside the welding machine. Further- more it must be possible to produce several mesh products simultaneously.

The method according to the invention for producing mesh products from groups of perpendicularly intersecting longitudinal and transverse elements that are welded together at the intersection points by the electric resistance welding method is characterised in that firstly at least one group of longitudinal elements assigned to a mesh product is put down in a fixed cycle with predetermined lateral spacing, next a group or groups are jointly moved transversely into the longitudinal element feeding plane of the welding machine, the groups of longitudinal elements are arranged in a predetermined

® 4 PCT/AT2005/000253 position inside the working area of the welding machine, the respective transverse elements are fed individually in the transverse direction to the welding line of the welding machine into the position predetermined by the associated group of longitudinal elements, and welding units that are not required for welding the transverse elements to the longitudinal elements are pushed out of the area of the longitudinal elements parallel to the welding line and fixed outside the outermost longitudinal elements.

The invention furthermore relates to a welding machine of the type indicated in the introduction, with the characteristics that for separating the longitudinal elements and for putting the longitudinal elements down in at least one group, at least one longitudinal element feeding device movable transversely to the longitudinal element feeding direction is provided, for the picking up of the longitudinal elements by the longitudinal element feeding device a shifting device is provided that can be shifted transversely to the longitudinal element feeding direction and can also be raised and lowered in the vertical direction, for the taking-over of the group or groups of longitudinal elements by the shifting device a receiving table is provided, for pushing the longitudinal elements into the welding machine a push-in carriage is provided that can be moved in the longitudinal element feeding direction, for feeding the transverse elements into, for every transverse element of a group, a predetermined welding position along the welding line two positioning devices movable along the welding line are provided, each of which comprises a conveying device for conveying the transverse elements into a transfer position that lies as close as possible in the area of the welding line of the welding machine as well as a swivelling feeding and tautening device for the transverse elements for moving the transverse elements from the transfer position into the welding line of the welding machine, and every upper welding head can be clamped to a stationary upper connecting beam extending above the longitudinal element

® 5 PCT/AT2005/000253 feeding plane transversely to the welding line and every lower welding head can be clamped to a stationary lower connecting beam extending underneath the longitudinal element feeding plane transversely to the welding line, for shifting the welding units transversely to the longitudinal element feeding direction along the welding line the upper welding head of each welding unit can with the aid of a clamping device be docked to an adjusting device movable parallel to the welding line and arranged above the longitudinal element feeding plane and the bottom welding head of the same welding unit can at the same time with the aid of a further clamping device be docked to an adjusting device movable parallel to the welding line and arranged underneath the longitudinal element feeding plane and the two welding heads can be detached from their respective connecting beams, and a control system is provided which, depending on the welding program for the mesh product to be produced, adapts to one another the positioning of the adjusting devices for the welding units, the moving of the positioning devices, the movements of the conveying devices and of the feeding and tautening devices for the transverse elements, the positioning of the longitudinal element feeding devices, the transverse shifting of the shifting carriage, the control of the stop edge as well as the pushing-in movement of the push-in carriage, and issues the corresponding control commands.

Preferably every longitudinal element feeding device comprises at least one storage magazine for cut-to-length longitudinal elements, a device for separating the longitudinal elements as well as an ejection opening open to the bottom that can be closed off with a controllable flap. According to a further characteristic of the invention the shifting device comprises a shifting carriage movable transversely to the longitudinal element feeding direction on two tracks, which is provided with several raisable and lowerable receiving slats distributed in the longitudinal element feeding direction, wherein the upper

® 6 PCT/AT2005/000253 sides of the receiving slats facing the ejection openings are provided with several recesses for accommodating the longitudinal elements.

According to a further development of the invention it is provided that the receiving table comprises several transverse spars running transversely to the longitudinal element feeding direction and extending over the operating width of the welding machine, wherein the distribution is chosen in such a way that the receiving strips can be positioned between the transverse spars and the transverse spars located closest to the welding machine are closer together than in the remaining area of the receiving table.

Other characteristics and advantages of the invention will be explained in more detail hereinafter by means of an exemplified embodiment with reference to the drawings, wherein: Fig. 1 is a diagrammatic side view of a welding machine according to the invention seen in the production direction, Fig. 2 is a diagrammatic side view of a conveying device according to the invention and of a feeding and tautening device for the transverse elements each seen transversely to the production direction, Fig. 3 is a diagrammatic side view of the conveying device and of the feeding and tautening device for the transverse elements each seen in the production direction, Fig. 4 is a diagrammatic vertical projection of a feeding device for the longitudinal elements, and Fig. 5 is a diagrammatic horizontal projection of the feeding device for the longitudinal elements.

The welding machine illustrated diagrammatically in Fig. 1-5 serves to produce mesh products G of a finite length, and which each consist of several longitudinal elements L, L’ spaced from one another and several transverse elements Q also spaced from one another and which intersect the former at a

® 7 PCT/AT2005/000253 right angle, wherein the longitudinal and transverse elements are welded together at their intersection points. Within the framework of the invention the longitudinal and transverse elements may have any cross-sectional shape. The longitudinal and transverse elements may, for example, have round cross- sections with a smooth or ribbed surface, as used for example as wires of reinforcing mats. However, within the framework of the invention the longi- tudinal and transverse elements within a mesh product G may also have different cross-sectional shapes, as is the case for example with grates, where the longitudinal elements consist of flat strips whereas the transverse elements preferably have a round or polygonal cross-section. The welding machine according to the invention makes it possible to produce the mesh product G at any place inside the working area A-A (Fig. 5) of the welding machine. The choice of the production place depends essentially on the optimal distribution of the welding current required to produce the mesh product G over the width of the welding machine.

The longitudinal elements L, L’ are fed to the welding machine, as described later in Fig. 4 and 5, parallel to one another with a mutual selectable spacing, the so-called longitudinal element pitch, along a horizontal longitudinal element feeding plane X-X (Fig. 2) in a feeding direction P1. Longitudinal elements that have already been cut-to-length are fed in so as to produce a mesh product G with predetermined dimensions.

The welding machine illustrated diagrammatically in Fig. 1 comprises at each side an upright 1 and 1’, respectively, arranged outside the working area A-A of the welding machine, and which are connected to one another by a stationary upper connecting beam 2 extending above the longitudinal element feeding plane X-X and a stationary lower connecting beam 3 extending

® 8 PCT/AT2005/000253 ® underneath the longitudinal element feeding plane X-X. To weld the transverse elements Q to the longitudinal elements L, L’, the welding machine comprises several welding units 4, which are arranged in a welding line S-S extending transversely to the longitudinal element feeding plane X-X. Each welding unit 4 has an upper welding head 5 with an upper electrode 6, as well as a lower welding head 7 with a lower electrode 8 which can be moved against the upper electrode 6, the upper and lower electrodes 6, 8 co-operating during the welding of the transverse element QS located in the welding line _S-S to the longitudinal elements L, L’. Depending on the welding program and the mesh product to be produced, to carry out the welding either the upper electrode 6 is moved against the stationary lower electrode 8 or vice-versa. Within the framework of the invention it is also possible, however, that to carry out the welding, both the upper electrode 6 as well as the lower electrode 8 are moved against one another. The number of welding units 4 corresponds at least to the maximum number of longitudinal elements L, L’ in the mesh product G to be produced, but preferably is chosen greater than this. In this case the welding units that are not required for welding the mesh product G are placed in parking positions 4’ and 4” on either side at the edge of the working area A-A of the welding machine outside the outermost longitudinal element L of the mesh product to be product G.

For positioning the welding units 4’, 4” and for positioning the welding units 4 in accordance with the desired longitudinal element pitch in each instance in accordance with the directions of the double arrow P2 along the welding line

S-S, an upper adjusting carriage 9 is provided for the upper welding heads 5 and a lower adjusting carriage 10 for the lower welding heads 7, wherein per positioning operation the adjusting carriages 9, 10 in each instance move only

® 9 PCT/AT2005/000253 ® one welding head 5, 7 into the welding position.

The adjusting carriages 9, 10 are each fixedly connected to the strands 11’ and 11”, respectively, of a toothed belt 11, which with the aid of a drive unit 12 can be driven in the directions of the double arrow P3 and is guided over several guide pulleys 13 in such a way that the strands 11’, 11” are in each instance moved simul- taneously in the same direction of the double arrow P2. Because of this coupling the upper and the lower adjusting carriages 9, 10 always move synchronously in the directions of the double arrow P4, so that the upper and lower welding heads 5, 7 of a welding unit 4, 4’, 4” are positioned jointly.

The drive unit 12 comprises a drive wheel 14 driven by a drive motor 13. Within the framework of the invention it is also possible to use other drive units that ensure a synchronous moving of the adjusting carriages 9, 10. These may, for example, be spindle drives, one each for an adjusting carriage, which outside the welding line are coupled to ensure joint moving, e.g. by way of a belt.

The adjusting carriages 9, 10 move on upper guide rails 16, 16’ and lower guide rails 17, 17’, respectively, extending parallel to the welding line S-S, the guide rails being fastened to the respective connecting beams 2, 3. To position the welding units 4, 4’, 4", the respective upper welding head 5 is detached from the upper connecting beam 9, and the respective lower welding head 7 from the lower connecting beam 10. The coupling of the upper welding head 5 to the upper adjusting carriage 9 takes place by means of diagrammatically indicated clamping cylinders 18, 18’, which engage in correspondingly shaped seats 19, 19’ of the upper welding head 5. The corresponding coupling of the lower welding head 7 to the lower adjusting carriage 10 takes place by means of diagrammatically indicated clamping cylinders 20, 20’, which engage in correspondingly shaped seats 21, 21’ of the lower welding head 7. After the positioning of a welding unit 4 in its welding position, the upper and lower

® 10 PCT/AT2005/000253 _ welding heads 5, 7 are each detached from the respective adjusting carriage 9, 10 and are fixedly connected to the upper and lower connecting beams 2, 3 respectively. A detailed description of the positioning of the welding units can be noted from the Austrian patent application AT - A 533/2004.

The transverse elements are first transported by two conveying devices 22, 22’ into the area of the welding line S-S, from where, as illustrated in Fig. 2 and 3, they are taken over by two feeding and tautening devices 23, 23’ and brought into the welding line S-S. To position the transverse elements transversely to the longitudinal element feeding direction P1 along the welding line S-S, the conveying device 22 and the feeding and tautening device 23 are arranged on a carriage 24 that can be moved along the welding line S-S in accordance with the directions of the double arrow P5 (Fig. 3), and the conveying device 22° and the feeding and tautening device 23’ are ranged on another positioning carriage 24’ (Fig. 3) that can be moved along the welding line S-S in accordance with the directions of the double arrow P5’, in each case outside the outermost longitudinal elements L. The positioning carriage 24 can be moved parallel to the welding line S-S by way of an upper guide block 25 (Fig. 3) on an upper guide track 26 and by way of a lower guide block 27 (Fig. 3) on a lower guide track 28. The positioning carriage 24’ can be moved parallel to the welding line S-S by way of an upper guide block 25’ on an upper guide track 26’ and by way of a lower guide block 27’ on a lower guide track 28’. The guide tracks 26, 26’; 28, 28’ are fastened to a transverse beam 29 extending parallel to the welding line S-S, which by way of two side plates 30, 30’ is connected to the machine uprights 1, 1’. The positioning of the positioning carriages 24, 24' takes place in each case by an adjusting spindle 31, 31’, respectively, which are mounted in spindle mountings 32, 33

® 11 PCT/AT2005/000253 and 32’, 33’ respectively in the transverse beam 29. The moving of the adjusting spindles 31, 31’ takes place in each case by means of a drive 34, 34’ which can be driven in the directions of the double arrow P86, and which are each connected by way of a drive belt 35, 35’ to a drive wheel 36, 36’ of the adjusting spindles 31, 31’. The coupling of the adjusting spindles 31, 31’ to the positioning carriages 24, 24’ takes place in each case by means of spindle nuts 37, 37°.

As illustrated in Fig. 2 and 3, the transverse elements Q are fed from one or several storage magazines 38 (Fig. 4) in the arrow direction P7 transversely to their longitudinal axis to the conveying devices 22, 22’, wherein for the sake of clarity Fig. 2 only shows the conveying device 22 and the feeding and tautening device 23. If there are several storage magazines 38, for reasons of space these are preferably arranged vertically above one another, in which case from every storage magazine 38 the separated transverse elements Q are passed via a guide track into the transfer compartment of a collecting chain. In this case the transverse elements Q are fed by the collecting chain into the conveying devices 22, 22’. The conveying devices 22, 22’ each have a conveyor chain 39, 39’, which are guided over drive pulleys 40, 40’ and deflection pulleys 41, 41’. The conveyor chains 39, 39’ are driven in a fixed cycle in the arrow direction P8 by a drive shaft 42 extending over the operating width of the welding machine and mounted in the side plates 30, 30’, wherein the drive pulleys 40, 40’ are connected to this drive shaft 42 rotationally fixed but movable along the drive shaft 42. The driving of the drive shaft 42 takes place by way of a drive wheel 43 mounted on the side plate 30. The conveying devices 22, 22’ each have a bracket 44, 44’, which carry bearings 45, 45’ for the drive shaft 42 and bearings 46, 46’ for the deflection

® 12 PCT/AT2005/000253 pulleys 41, 41’. The conveyor chains 39, 39’ comprise regularly distributed drivers 46, into which in each instance one individual transverse element is placed and which move the fed-in transverse elements Q on in the arrow direction P8. The conveyor chains 39, 39’ are tensioned with the aid of chain tighteners 48, 48’. Several guide plates 49 and lateral deflector plates 50 hold the transverse elements Q on the conveyor chains 39, 39’ and prevent them from jumping out of the drivers 47.

The conveyor chains 39, 39’ convey the transverse elements Q individually in a fixed-cycle into a transfer position which lies as close as possible in the area of the welding line S-S. This transfer position is in each instance defined by a positioning finger 51, 51’, which with the aid of a drive shaft 52 extending over the operating width of the welding machine, per operating cycle are turned once by 360° in the arrow direction P9, wherein the points of the positioning fingers 51, 51’ describe the movement path B. The positioning fingers 51, 51’ are connected to the drive shaft 52 rotationally rigid but movable along the same. The transverse element Q is taken over from the positioning fingers 51, 51’ by the drivers 47 of the conveyor chain 39, 39’ and fixed in its position, the transverse element Q being pushed by two hold-back fingers 53, 53’, each by a torsion spring 54, 54’, against the positioning fingers 51, 51’. Independent of the dimensions of the transverse element Q, the position of the transverse element Q in the transfer position is defined exactly by the position of the positioning fingers 51, 51’. The drive shaft 52 for the positioning fingers 51, 51’ is driven by a drive belt 55. The drive belt 55 is guided over a drive wheel 56 connected to the drive shaft 52, and is driven in arrow direction P10 with the aid of a driving wheel 57 of a drive 58.

The drive belt 55 is tensioned tightly by a belt tightener 59. After transfer of the transverse elements Q from the conveyor chains 39, 39’ to the positioning

® 13 PCT/AT2005/000253 ® fingers 51, 51’, the conveyor chains 39, 39’ are moved on in a fixed-cycle in arrow direction P8.

Every feeding and tautening device 23, 23’ for the transverse elements Q has a receiver 60, 60’ which is arranged on the associated positioning carriages 24, 24’. Arranged on each receiver 60, 60’ is a feeding cylinder 61, 61’, wherein each piston rod of a feeding cylinder 61, 61’ can in each stance be moved in the directions of the double arrow P11 and is connected to a swivel arm 62, 62’. The swivel arms 62, 62’ are mounted rotatably in the axes of rotation D1, D1’ in the respective seats 60, 60’. The feeding cylinders 61, 61’ each have two end-position dampers 63, 63’, which ensure a quiet, impact- free movement. Attached to each swivel arm 62, 62’ is a tautening cylinder 64, 64’, wherein each piston rod of a tautening cylinder 64, 64’ can in each instance be moved in the directions of the double arrow P12, P12’ and is connected to a tautening lever 65, 65’. Each tautening lever 65, 65 is mounted rotatably in an axis of rotation D2, D2’ in the respective swivel arm 62, 62’. Attached to each tautening lever 65, 65’ is a clamping cylinder 66, 66°’, wherein each piston rod of a clamping cylinder 66, 66’ can in each instance be moved in the directions of the double arrow P13 and is connected to a two-armed clamping lever 67, 67’. Each clamping lever 67, 67’ is mounted rotatably in an axis of rotation D3, D3’ in the respective tautening lever 65, 65’ in accordance with the directions of the double arrow P14, P14’.

The clamping cylinders 66, 66’ each have an end-position damping 68, which ensures a quiet, impact-free movement. Attached to the free end of each clamping lever 67, 67’ is a clamping jaw 69, which cooperates with a clamping jaw 70 mounted stationary on the respective tautening lever 65, 65°.

All clamping jaws 69, 69’, 70, 70’ are mounted in electrically insulated fashion on their fastening levers 67, 67; 65, 65°.

® 14 PCT/AT2005/000253 ®

The feeding of the transverse element Q from the transfer position of the positioning fingers 51, 51’ into the welding line S-S takes place as follows:

By actuating the feeding cylinders 61, 61’ in the relevant direction of the double arrow P11, the associated feeding and tautening devices 23, 23’ are jointly swivelled in the corresponding direction of the double arrow P15 in such a way that the clamping jaws 69, 69’; 70, 70’ move out of the welding line

S-S into the transfer position of the positioning fingers 51, 51’. By next actuating the clamping cylinders 66, 66’ in the corresponding direction of the double arrow P13, the clamping jaws 69, 69’; 70, 70’ close and clamp the transverse element Q held by the positioning fingers 51, 51° and the hold-back fingers 53, 53’ at both its ends. By subsequent actuation of the feeding cylinders 61, 61’ in the opposite direction of the double arrow P11, the associated feeding and tautening devices 23, 23’ are jointly swivelled in the corresponding direction of the double arrow P15 in such a way that the transverse element Q clamped by the clamping jaws 69, 69’; 70, 70’ moves out of the transfer position of the positioning fingers 51, 51’ into the welding line S-S, wherein the transverse element Q is combed out of the hold-back fingers 53, 53’. In doing so, the transverse element Q describes the movement path Z in the arraw direction P16. During this movement the tautening cylinders 64, 64’ are actuated in the corresponding directions of the double arrows P12, P12’, so that the transverse element Q is tautened in its longitudinal direction. After the transfer of the transverse element Q the positioning fingers 51, 51’ are turned by 360° on the movement path B and take a new transverse element from the drivers 47 of the conveyor chains 39, 39°.

Optionally, already after the closing of the electrodes 6,8 or only after the welding of the transverse element QS located in the welding line S-S to the

® 15 PCT/AT2005/000253 longitudinal elements L, L’, the clamping jaws 69, 69’ are opened by the appropriate actuating of the clamping cylinders 66, 66°, and the piston rods of the tautening cylinders 64, 64’ move back into their starting position. The welded transverse element QS together with the longitudinal elements L, L' is moved out of the welding line S-S by a selectable length, the so-called transverse element pitch, so that in a subsequent operating cycle of the welding machine a new transverse element Q can be fed in for welding to the longitudinal elements L, L'. _

The feeding device for the longitudinal elements illustrated diagrammatically in

Fig. 4 and 5 comprises two machine frames 71, 71’, which extend transversely to the longitudinal element feeding direction P1. Arranged in the machine frames 71, 71’ is at least one longitudinal element feeding device 72 movable horizontally in the directions of the double arrow P17. To be able to simultaneously feed longitudinal elements of different dimensions and/or to speed up the feeding of longitudinal elements L, L’, within the framework of the invention a further longitudinal element feeding device 72’, movable in the directions of the double arrow P17’, may be arranged in the machine frames 71, 71’. Each longitudinal element feeding device 72, 72’ has a stock of longitudinal elements L, L’, which are separated in the longitudinal element feeding devices 72, 72’ and fed individually to an ejection opening 73, 73’.

Each ejection opening 73, 73’ can be closed with a movable, controllable flap.

Arranged underneath the ejection openings 73, 73’ is a shifting carriage 74, which can be moved horizontally in the directions of the double arrow P18 from a starting position 74’ into operating positions 74 and into a transfer position 74" transversely to the longitudinal element feeding direction P1. The shifting carriage 74 comprises two uprights 75, 75’ as well as several horizontal receiving slats 77, 77' extending transversely to the longitudinal

® 16 PCT/AT2005/000253 element feeding direction P1, and which on their upper sides facing the ejection openings 73, 73’ have several recesses for receiving the longitudinal elements L, L’, and which receiving slats 77, 77’ can be raised and lowered in the directions of the double arrow P19. Within the framework of the invention the receiving slats 77, 77’ may have different shapes and may, for example, be in the form of toothed slats.

The longitudinal element feeding devices 72, 72’ place individual longitudinal elements L, L' the one after the other on the toothed slats 77, 77’ with a lateral spacing corresponding to the longitudinal element pitch in the mesh product G to be produced, the flaps of the longitudinal element feeding devices 72, 72’ being controlled correspondingly and the longitudinal element feeding devices 72, 72' and/or the shifting carriage 74 being moved in the relevant directions P17, P17’ and P18, respectively. Within the framework of the invention it is possible in this way, if desired, to place several groups of longitudinal elements L, L’ on the toothed slats 77, 77’ and by doing so to supply the welding machine with the longitudinal elements L, L’ of several mesh products G. Within the framework of the invention it is also possible, however, for reasons of space to arrange several longitudinal element feeding devices 72, 72’ above one another in the vertical direction, in which case from each longitudinal element feeding device 72, 72’ the separated longitudinal elements L, L’ are passed via a guide track into the transfer compartments of a distributor chain. In this case the longitudinal elements L, L' are placed on the toothed slats 77, 77’ by the distributor chain with selectable lateral spacing.

The toothed slats 77, 77° are distributed uniformly parallel to the longitudinal element feeding direction P1 in such a way that they can receive the longitudinal elements L, L' if possible without sagging. The toothed slats 77’ that lie closest to the welding machine are made broader and closer together

® 17 PCT/AT2005/000253 than the toothed slats 77 in the remaining area of the shifting carriage 74, so that also short longitudinal elements can be securely deposited on the toothed slats 77, 77’. The toothed slats 77, 77’ are provided on their upper sides facing the ejection openings 73, 73’ with uniformly distributed, saw-tooth shaped recesses, which are designed in such a way that they prevent a lateral slipping of the longitudinal elements L, L’ on the toothed strips 77, 77’. The distances between the recesses correspond to half the smallest possible longitudinal element pitch that can be produced by the welding machine.

After all the longitudinal elements L, L' of the mesh product G or mesh products to be produced have been deposited on the toothed slats 77, 77°, the shifting carriage 74 with the longitudinal elements L, L' moves in the corresponding direction of the double arrow P18 transversely to the longitudinal element feeding direction P1 into its transfer position 74" in the inlet area of the welding machine, so as to be able to transfer the group or groups of longitudinal elements L, L’ jointly to the welding machine. The welding machine is shown diagrammatically in Fig. 4 and 5 by the machine uprights 1, 1’, the upper connecting beam 2 and the welding line S-S.

Arranged in the inlet area of the welding machine is a receiving table 78, which has several side posts 79 as well as several transverse spars 80 extending transversely to the longitudinal element feeding direction P1 across the operating width A-A of the welding machine, wherein the upper sides of the transverse spars 80 define the longitudinal element feeding plane X-X of the welding machine. The transverse spars 80 are distributed in such a way that the toothed slats 77. 77’ can be positioned between the transverse spars 80. To be able to support also short longitudinal elements L, L' without significant sagging, the transverse spars 80 that lie closest to the welding machine are placed closer together than in the remaining area of the receiving

® 18 PCT/AT2005/000253 ® table 78. To deposit the longitudinal elements L, L' on the transverse spars 80, in the transfer position 74” of the shifting carriage 74 the toothed slats 77, 77’ are lowered in the corresponding direction of the double arrow P19. Every group of longitudinal elements L, L’ can be transferred at a selectable place inside the working area A-A of the welding machine to the transverse spars 80, wherein the choice of transfer place is determined by the transverse shifting of the shifting carriage 74. Within the framework of the invention it is also possible, however, to fix the transfer place already during the depositing of the longitudinal elements L, L' on the toothed slats 77, 77 by a corresponding positioning of the longitudinal elements L, L’ on the toothed slats 77, 77’, and to shift always the shifting carriage 74 into its outermost transfer position. Depending on the position of the longitudinal elements L, L’ in the working area A-A, the storage magazine 38 for the transverse elements

Q must also be moved in the directions of the double arrow P20.

Arranged in the inlet area of the welding machine is a push-in carriage 81, which can be moved on two parallel rails 82, 82’ in the directions of the double arrow P21 parallel to the longitudinal element feeding direction P1 from a take-over position for taking over the longitudinal elements L, L' from the toothed slats 77,.77" into a transfer position 81 for transferring the longitudinal elements L, L’ to the welding machine. The push-in carriage 81 has several clamping tong pairs 83, which can be accurately positioned and fixed in the longitudinal element pitch of the mesh product G to be produced.

The number of clamping tong pairs 83 is at least equal to the maximum number of longitudinal elements L, L’ that can be processed with the welding plant according to the invention.

In the take-over position 81’ of the push-in carriage the front ends of the longitudinal elements L, L’ are first held loosely with the aid of the clamping

® 19 PCT/AT2005/000253 tong pairs 83 so as to be able to align them in the longitudinal direction to the same starting position with their ends facing the welding machine. The aligning of the longitudinal elements L, L" takes place by a stop edge 84 extending transversely to the longitudinal element feeding direction P1, which is swivelled in the longitudinal element feeding plane X-X and moved towards the longitudinal element ends in the corresponding direction of the double arrow

P22. After the aligning, the longitudinal elements L, L’ are clamped tight by the clamping tong pairs 83, and the stop edge swivels up so as to free the push-in path into the welding machine. Within the framework of the invention it is possible to carry out the aligning movement of the stop edge 84 by only one shifting of the stop edge 84 obliquely to the longitudinal element feeding plane

X-X.

With the aid of the push-in carriage 81 the longitudinal elements L, L’ are pushed forward in the corresponding direction of the double arrow P21 into the transfer position illustrated in Fig. 5 up to a fixed row of clamping elements 85. The clamping elements 85 are preferably each fastened to the immovable part of the lower welding head 7. By different selectable repeat movements in the corresponding directions of the double arrow P21 of the push-in carriage 81, different longitudinal elements protrusions can be produced in the mesh product G.

The welding machine has a control system which in dependence on the welding program for the mesh product G to be produced adapts to one another the positioning of the adjusting carriages 9, 10 for the welding units 4, 4°, 4”, the moving of the positioning carriages 24, 24’ with the conveying devices 22, 22’ and the feeding and tautening devices 23, 23’ for the transverse elements

Q, as well as the positioning of the longitudinal element feeding devices 72, 72’, the transverse shifting of the shifting carriage 74, the control of the stop

® 20 PCT/AT2005/000253 _ edge 84, and the push-in movement of the push-in carriage 81, and issues the corresponding control commands.

Within the framework of the invention it is possible, by installing a further storage magazine for the transverse elements, two further positioning carriages 24, 24’ each with a conveying device 22, 22’ and each a feeding and tautening device 23, 23’ for the transverse elements Q, to produce two mesh products G simultaneously in the welding machine. In this case the simul- taneously produced mesh products G may have different numbers of longitudinal and transverse elements, different longitudinal and transverse element diameters, different longitudinal element lengths and different longitudinal and transverse element pitches, so that two identical, or also completely different mesh products G can be produced simultaneously in one operation by the welding plant according to the invention. * a»

Claims (12)

® 21 PCT/AT2005/000253 ® Claims:

1. Method for producing mesh products (G) from groups of perpendicularly intersecting longitudinal and transverse elements (L, L'; Q) that are welded together at the intersection points by the electric resistance welding method, characterised in that firstly at least one group of longitudinal elements (L, L') assigned to a mesh product (G) is put down in a fixed cycle with predetermined lateral spacing, next a group or groups are jointly moved transversely into the longitudinal element feeding plane (X-X) of the welding machine, the groups of longitudinal elements (L, L’) are arranged in a predetermined position inside the working area (A-A) of the welding machine, the respective transverse elements (Q) are fed individually in the transverse direction to the welding line (S-S) of the welding machine into the position predetermined by the associated group of longitudinal elements (L, L’), and welding units that are not required for welding the transverse elements (Q) to the longitudinal elements (L, L’) are pushed out of the area of the longitudinal elements (L, L’) parallel to the welding line and fixed outside the outermost longitudinal elements (L, L').

2. Method according to claim 1, characterised in that the transverse elements (Q) are tautened in their longitudinal direction, wherein the tautening preferably takes place during the feeding of the transverse elements (Q) into the welding line (S-S).

3. Welding machine operating according to the electric resistance welding method for implementing the method according to claim 1 or 2, comprising a device for the transverse distribution of the longitudinal elements, a device for advancing the longitudinal elements in the longitudinal element feeding direction along a horizontal longitudinal

® 22 PCT/AT2005/000253 element feeding plane, a device for the transverse conveying of cut-to- length transverse elements into the area of the longitudinal element feeding plane, a device for feeding the transverse elements into the welding line of the welding machine extending transversely to the longitudinal element feeding direction, a device for tautening the transverse elements, several welding units arranged in a row transversely to the longitudinal element feeding direction and each consisting of an upper and lower welding head, and a conveying device that can be coupled to the welding units for shifting and positioning the welding units transversely to the longitudinal element feeding direction, characterised in that for separating the longitudinal elements (L, L’) and for putting the longitudinal elements (L, L’) down in at least one group, at least one longitudinal element feeding device (72, 72°) movable transversely to the longitudinal element feeding direction (P1) is provided, for the picking up of the longitudinal elements (L, L’) by the longitudinal element feeding device (72, 72’) a shifting device (74) is provided that can be shifted transversely to the longitudinal element feeding direction (P1) and can also be raised and lowered in the vertical direction (P19), for the taking- over of the group or groups of longitudinal elements (L, L’) by the shifting device (74) a receiving table (78) is provided, for pushing the longitudinal elements (L, L’) into the welding machine a push-in carriage (81) is provided that can be moved (P21) in the longitudinal element feeding direction (P1), for feeding the transverse elements (Q) into, for every transverse element (Q) of a group, a predetermined welding position along the welding line (S-S) two positioning devices (24, 24’) movable along the welding line (S-S) are provided, each of which comprises a conveying device (22, 22’) for conveying the transverse elements (Q) into a transfer position that lies as close as possible in the area of the welding line (S-S) of the welding machine as well as a swivelling feeding

® 23 PCT/AT2005/000253 and tautening device (23, 23’) for the transverse elements (Q) for moving the transverse elements (Q) from the transfer position into the welding line (S-S) of the welding machine, and every upper welding head (5) can be clamped to a stationary upper connecting beam (2) extending above the longitudinal element feeding plane (X-X) transversely to the welding line (S-S) and every lower welding head (7) can be clamped to a stationary lower connecting beam (3) extending underneath the longitudinal element feeding plane (X-X) transversely to the welding line (S-S), for shifting the welding units (4, 4’, 4”) transversely to the longitudinal element feeding direction (P1) along the welding line (S-S) the upper welding head (5) of each welding unit (4, 4°, 4”) can with the aid of a clamping device (18, 18’) be docked to an adjusting device (9) movable parallel to the welding line (S-S) and arranged above the longitudinal element feeding plane (X-X) and the bottom welding head (7) of the same welding unit (4, 4°, 4”) can at the same time with the aid of a further clamping device (20, 20’) be docked to an adjusting device (10) movable parallel to the welding line (S-S) and arranged underneath the longitudinal element feeding plane (X-X) and the two welding heads (5, 7) can be detached from their respective connecting beams (2, 3), and a control_system is provided which, depending on the welding program for the mesh product (G) to be produced, adapts to one another the positioning of the adjusting devices (9, 10) for the welding units (4, 4’, 4"), the moving of the positioning devices (24, 24’), the movements of the conveying devices (22, 22’) and of the feeding and tautening devices (23, 23’) for the transverse elements (Q), the positioning of the longitudinal element feeding devices (72, 72’), the transverse shifting of the shifting carriage (74), the control of the stop edge (84) as well as the pushing-in movement of the push-in carriage (81), and issues the corresponding control commands.

® 24 PCT/AT2005/000253

4. Welding machine according to claim 3, characterised in that every longitudinal element feeding device (72, 72’) comprises at least one storage magazine for cut-to-length longitudinal elements (L, L’), a device for separating the longitudinal elements (L, L') as well as an ejection opening (73, 73’) open to the bottom that can be closed off with a controllable flap.

5. Welding machine according to claim 3 or 4, characterised in that the shifting device comprises a shifting carriage (74) movable transversely to the longitudinal element feeding direction (P1) on two tracks (76, 76°), which is provided with several raisable and lowerable (P19) receiving slats (77, 77’) distributed in the longitudinal element feeding direction (P1), wherein the upper sides of the receiving slats (77, 77’) facing the ejection openings (73, 73’) are provided with several recesses for accommodating the longitudinal elements (L, L').

6. Welding machine according to claim 5, characterised in that the receiving slats (77, 77’), on their upper sides, have uniformly distributed, saw- tooth shaped recesses, wherein the lateral distances between the recesses correspond to half the smallest possible longitudinal element pitch that can be produced by the welding machine, and the receiving slats (77') that lie closest to the welding machine are made broader and closer together than the receiving slats (77) in the remaining area of the shifting carriage (74).

7. Welding machine according to claims 3 to 6, characterised in that the receiving table (78) comprises several transverse spars (80) running transversely to the longitudinal element feeding direction (P1) and extending over the operating width (A-A) of the welding machine, wherein the distribution is chosen in such a way that the receiving strips (77, 77’) can be positioned between the transverse spars (80) and the transverse spars located closest to the welding machine are closer together than in the remaining area of the receiving table (78).

® 25 PCT/AT2005/000253

8. Welding machine according to any one of claims 3 to 7, characterised in that, for aligning the ends of the longitudinal elements (L, L’} facing the welding machine, a stop edge (84) is provided which can be moved parallel to the longitudinal element feeding direction (P1), and can be moved away from the longitudinal element feeding plane (X-X) of the welding machine.

9. Welding machine according to any one of the claims 3 to 9, characterised in that for clamping at least the front ends of the longitudinal elements (L, L') facing the welding machine the push-in carriage (81) has at least one clamping tong pair (83) each.

10. Welding machine according to any one of the claims 3 to 9, characterised in that each conveying device (22, 22’) for the transverse elements (Q) has at least one conveyor chain (39, 39’) that can be driven in a fixed cycle (P8) and comprises several drivers (47), and in the transfer position the transverse elements (Q) can by a rotating (P9) positioning finger (51, 51’) be combed out of the drivers (47) of the conveyor chain (39, 39’) and together with at least one hold-back finger (53, 53°) be fixed in position.

11. Welding machine according to any one of the claims 3 to 10, characterised in that each feeding and tautening device (23, 23’), for transferring the transverse elements (Q) from the transfer position into the welding line (S-S) of the welding machine, comprises a swivel arm (62, 62’) which can be swivelled with the aid of a working cylinder (61, 61’), in that for tautening the transverse elements (Q) in each instance a tautening lever (65, 65’) is provided, mounted rotatably on the respective swivel arm (62, 62’) and which can be swivelled (P12, P12’) with the aid of a working cylinder (64, 64’), wherein in order to clamp the ends of the transverse elements (Q) to the respective tautening lever (65, 65°) in each instance a clamping jaw (69, 69’) is provided, which can be closed (P14, P14’) with the aid of a working cylinder (66, 66°), as well as a

® 26 PCT/AT2005/000253 ® clamping jaw (70, 70’) which is fastened to the tautening lever (65, 65°) and co-operates with the clamping jaw (69, 69’).

12. Welding machine according to any one of the claims 3 to 11, characterised in that the adjusting device (9) for the upper welding head (5) comprises an upper adjusting carriage (9) movable (P4) along at least one stationary guide rail (16, 16’) arranged on the upper connecting beam (2) and the adjusting device (10) for the lower welding head (7) comprises a lower adjusting carriage (10) movable (P4) along at least one stationary guide rail (17, 17’) arranged on the lower connecting beam (3), wherein both adjusting carriages (9, 10) are fixedly connected to the drive system (11, 11’, 11”, 12, 13, 14, 15) for the simultaneous and joint moving (P4) along the welding line (S-S).