EP0399996B1 - Machine for welding wire mesh - Google Patents

Abstract

PCT No. PCT/AT90/00049 Sec. 371 Date Jan. 10, 1991 Sec. 102(e) Date Jan. 10, 1991 PCT Filed May 23, 1990 PCT Pub. No. WO90/14181 PCT Pub. Date Nov. 29, 1990.A welding machine for manufacturing wire nets from mutually perpendicular longitudinal and transverse wires welded at the points of intersection comprises a device for feeding the longitudinal wires in a horizontal welding plane, two devices for simultaneously inserting two transverse wires (Q,Q'), arranged at equal distances on either side of insertion lines (K,K'), a welding electrode arrangement for carrying out two-point welding in the direction of the longitudinal wires, and two feeder arms (8,9) for transferring the transverse wires from the insertion lines to the welding lines (S, S'). The feeder arms are fitted with clamping devices (11,12) for the transverse wires and can be moved together back and forth between the insertion lines and the welding lines along predetermined tracks (U, U'; O, O'). At least one of the feeder arms can be moved by means of a mechanical drive (22) in order to prestress both transverse wires relative to the other feeder arm in the direction of the transverse wires, and the transverse wires are positioned precisely in accordance with the predetermined distribution of the transverse wires by means of pivotable positioning elements (17,17' ) provided in the region of the welding lines.

Description

The invention relates to a welding machine for producing grids from longitudinal and transverse wires which cross at right angles and are welded at the crossing points, with a device for feeding the longitudinal wires in a horizontal welding plane, two devices arranged at mutual spacing on the weft lines for simultaneous insertion of two transverse wires, one Welding electrode arrangement for carrying out a double-spot welding in the direction of the longitudinal wires, and two feeder arms for transferring the transverse wires from the weft lines to the weld lines, the feeder arms being arranged outside the outer longitudinal wires and by means of a common feeder arm carrier running perpendicular to the longitudinal wire direction on predetermined movement paths between the weft lines and the Welding lines can be moved back and forth.

In a lattice welding machine known from AT-PS 267.293, two cross wires are simultaneously fed onto two weft lines arranged at a fixed distance, conveyed into the welding lines by means of cross wire feeders and welded to the longitudinal wires with the aid of double-point welding electrodes. A deficiency of this known grid welding machine is that only grids can be produced with a single predetermined and unchangeable cross wire distance, which corresponds to the mutual distance of the cross wire weft lines.

This deficiency is remedied in a mesh welding machine of the type specified in the introduction, known from AT-PS 373.799, in which the fixed shot lines of the two cross wires are arranged at a fixed mutual distance, whereas the two welding lines are variable in position. The transfer of the cross wires from the infeed lines to the weld lines is carried out with a separate feeder for each cross wire, the feeders being attached to a common carrier. The cross wire feeder can be arranged both between the longitudinal wires, ie in the welding area, and outside of the welding area. In this known machine, however, a considerable effort is required to control the cross wire feeder, which is often superfluous, because in most applications standard grids with cross wire spacings are produced which are a multiple of a predetermined smallest basic division. Both of the known mesh welding machines discussed above have the additional disadvantage that the cross wires with more or less good alignment lie loosely in recesses in the cross wire feeder devices. This leads to an asymmetrical structure of the finished grid web, especially in the case of narrow-mesh grids with small cross-wire division and small cross-wire and line-wire diameters.

From SU-837.668 it is known to clamp a cross wire during feeding to the welding line, but the clamping force cannot be adjusted, but depends on the constructionally specified increase in distance of the clamping jaws during the feeding movement and on the spring constant of any relief springs.

The object of the invention is to provide a lattice welding machine of the type specified in the introduction, which makes it possible, using the advantages of double-spot welding, to produce lattices in a structurally simple and reliable manner, the cross-wire spacing of which corresponds to a predetermined smallest possible basic pitch or a multiple of this basic pitch of the transverse wires. The welding machine according to the invention is characterized in that the feeder arms are designed to accommodate both transverse wires and are equipped with clamping devices for the transverse wires, that at least one of the feeder arms for jointly biasing both transverse wires can be moved relative to the other feeder arm in the transverse wire direction by means of a power drive with adjustable clamping force and that in the area of the weld lines pivotable positioning members for exact positioning of the cross wires according to the specified cross wire pitch are provided.

As a result of the simultaneous tensioning of both cross wires before welding with the longitudinal wires with a tension that can be adjusted to the cross wire material, the unevenness in the cross wires caused by the straightening processes is advantageously compensated for and production-related asymmetries in the finished product, for example also due to thermal expansion during welding Avoid grid. The positioning elements ensure that the exact cross wire spacing is maintained and also cause damping of the vibrations that occur in the cross wires when they are transferred. According to the invention, grids with cross wire divisions, each of which is a multiple of a predetermined smallest basic division, in particular also close-mesh grids, can be produced with great accuracy.

It should be mentioned that it is known from DE-AS 1,552,137 and 1,566,526 in welding machines of a different type to design the feeder arms for jointly receiving both cross wires.

According to a preferred embodiment of the invention, at least one of the feeder arms is arranged on the feeder arm carrier so as to be displaceable relative to the other feeder arm for positioning. This enables the machine to be set to different grid widths. The movement paths of the feeder arms for the cross wires from the weft lines to the welding lines and the movement paths for the return movement are preferably each composed of a feed path and a tilting movement path.

According to a further feature of the invention, the welding machine is characterized in that the clamping devices for the transverse wires have openable and closable lower clamping jaws, which interact with associated upper clamping jaws, the upper clamping jaws each being provided with a plurality of latching recesses for receiving the transverse wires, the mutual distance of the given corresponds to the smallest cross wire pitch. In this way, the cross wires for the tensioning process and for transferring are held securely. Furthermore, grids can be produced whose spacing of the cross wires is a multiple of the smallest possible basic pitch of the cross wire pitch.

A further development of the invention has the features that the upper jaw of the supply-side clamping device forms a cutting tool and that at least two cross wire feeds are provided in a supply-side nozzle block, the outlet side of which has a cutting edge for interacting with the upper clamping jaw of the supply-side clamping device forming the cutting tool, around which Disconnect cross wires from the wire supply.

The feeder arm, which is removed from the feed side, can preferably be pivoted in the cross-wire direction by means of the power drive, the power drive preferably having a tensioning lever which can be actuated by a hydraulic cylinder which can be pressurized with adjustable pressure.

• Fig. 1 in perspektivischer Darstellung schematisch die wesentlichen Elemente einer erfindungsgemäßen Schweißmaschine;
• Fig. 2a schematisch die Übernahme- und Übergabepositionen sowie die Bewegungsbahnen der Klemmvorrichtungen für die Querdrähte, gesehen in Richtung der Pfeile IIa-IIa in Fig. 2b,
• Fig. 2b einen Detailschnitt durch die Klemmvorrichtungen nach der Linie IIb-IIb in Fig. 2a, und die
• Fig. 3a und 3b die Anordnungen der Schweißelektroden sowie mögliche Schweißpositionen der Querdrähte in der erfindungsgemäßen Schweißmaschine.

Further features of the invention are explained in more detail below using an exemplary embodiment of the invention with reference to the drawings. Show it:

• 1 schematically shows the essential elements of a welding machine according to the invention in a perspective representation;
• 2a schematically, the transfer and transfer positions and the movement paths of the clamping devices for the transverse wires, seen in the direction of the arrows IIa-IIa in Fig. 2b,
• Fig. 2b shows a detail section through the clamping devices along the line IIb-IIb in Fig. 2a, and
• 3a and 3b, the arrangements of the welding electrodes and possible welding positions of the cross wires in the welding machine according to the invention.

In the lattice welding machine shown in Fig. 1, two cross wires Q, Q 'are simultaneously in two welding lines S, S' with perpendicular to these in the direction of production P₁ advanced longitudinal wires L welded to a grid. The finished grid web is drawn out of the welding lines by means of feed rollers (not shown). The longitudinal wires L are fed to the welding lines S, S 'via a plurality of guide blocks 1 arranged next to one another, of which only one is shown in FIG. 1. Each guide block 1 essentially has a plurality of insertion nozzles arranged next to one another, which expediently consist of wear-resistant material and are loaded with longitudinal wires L depending on the desired line wire division. Each guide block 1 also has a lower and upper, appropriately V-shaped guide prism for each insertion nozzle, the guide prisms each being pressed against the longitudinal wires by means of a spring plate in order to ensure exact guidance of the longitudinal wires L. The guide blocks 1 are arranged on a rail, not shown, adjustable transversely to the direction of production P 1.

From supply spools, not shown, two cross wires Q, Q 'with a desired cross wire pitch in the finished grid corresponding, selectable mutual distance perpendicular to the direction of production P 1 in the direction of arrow P 2 in two by means of feed and straightening devices via a nozzle block 2 provided with a plurality of feed nozzles Weft lines K, K 'introduced. Each weft line K or K 'is determined by recesses which are formed between a plurality of rigid plates 3, 3' arranged transversely to the longitudinal wire array and a plurality of pivoting flaps 4, 4 'located exactly opposite these. The recesses are only roughly adapted to the cross wire diameter; only the recess R furthest away from the nozzle block 2 is provided with a centering piece precisely matched to the cross wire diameter for the purpose of precise fixing of the cross wires Q, Q '. The plates 3, 3 'are attached with their upper end to a plate carrier 5, 5' extending across the machine width. The flaps 4, 4 'are with their upper end at one each also over the Machine width extending, according to the double arrow P₃ pivotable valve shaft 6 and 6 'mounted. The pivoting movement of the flap shafts 6, 6 'is effected by means of a pivoting device 7 formed from a cam disk and rocker arms. As a result, the weft lines K, K 'are released for the transfer of the cross wires Q, Q' to be explained in the welding lines S, S '.

The feed nozzles in the nozzle block 2 have a mutual spacing corresponding to the smallest possible basic pitch a of the cross wire pitch in the grid to be manufactured and their dimensions are also adapted to the cross wire diameter to be processed. The amount of the smallest possible basic division a depends primarily on the type of grid to be produced, for example inch division or metric division.

The transfer of the cross wires Q, Q 'from the weft lines K, K' into the welding lines S, S 'is carried out by means of two pivotable feeder arms 8, 9, which are each arranged on the outer side edge of the lattice web to be produced on the machine frame. The two feeder arms 8, 9 are fastened on a common carrier 10. The feeder arm 9, which is removed from the feed side, is displaceably arranged perpendicular to the production direction P 1 in accordance with the double arrow P₄ on the support 10, so that it can assume any intermediate position Z indicated by dashed lines, which allows grid webs of a selectable width, i.e. selectable cross wire length.

The feed-side feeder arm 8 is provided with a clamping device 11 which is exactly aligned with the feed nozzles of the nozzle block 2 in the takeover position defined by the insertion lines K, K 'and is designed such that it clamps the transverse wires Q, Q' and, as explained below can also disconnect from the wire supply. The other feeder arm 9 is provided with a clamping device 12 which can clamp the cross wires Q, Q '.

After clamping the cross wires Q, Q ', the clamping devices 11, 12 move to that shown in Fig. 2 Trajectories in the direction of arrows U, U 'to separate the cross wires Q, Q' from the wire supply and transfer them from the takeover positions K, K 'to the welding lines S, S'. After welding of the transverse wires to the longitudinal wires, the clamping devices 11, 12 with the aid of the feeder arms 8, 9 perform the movements shown in FIG. 2 in the direction of the arrows O, O 'in order to move from the welding lines S, S' into the takeover positions K. , K 'to arrive and in the weft lines K, K' ready cross wires Q, Q 'to take over.

The movements O, O 'and U, U' consist of two coupled individual movements of the feeder arms 8, 9, etc. an essentially linear feed movement corresponding to the double arrow P₅ and a tilting movement corresponding to the double arrow P₆.

The carrier 10 is pivotally mounted on one end of a rocker arm 13 which is rigidly connected to a rocker shaft 14 at its other end. The feed movement in accordance with the double arrow P₅ is carried out by a feed device 15 consisting of a cam and rocker arm. The rocker arm 13 can be set into a tilting movement by means of a tilting device 16 consisting of a cam disk and rocker arm according to the double arrow P₆.

To maintain an exact cross wire division, the cross wires Q, Q 'by means of positioning arms 17, 17', which project from a swivel drive 18 by means of a swivel drive 18 in accordance with the double arrow P₇ and are provided at their free ends with recesses for the cross wires, in the welding lines S, S 'exactly positioned. The positioning arms 17, 17 'assume an upper working position when taking over the cross wires Q, Q' and during the welding process. The positioning arms 17, 17 'also have the task of damping the vibrations that occur during the transfer movement along the movement paths U, U' in the transverse wires Q, Q 'and completely eliminate them before the welding process. The locking recesses of the positioning arms 17, 17 'have a mutual distance which advantageously corresponds to the smallest possible basic pitch a of the cross wire pitch. The positioning arms 17, 17 'can be adjusted by means of an adjusting device 20 in the direction of production P₁ in order to be adapted precisely to the respective cross wire division.

After the already explained fixing by means of the clamping device 11, 12, the transverse wires Q, Q 'are tensioned during the feed movement on the movement paths U, U' with the aid of a tensioning lever 22 which can be actuated by a tensioning cylinder 21 and is pivotably mounted in the feeder arm 9 and which clamps the clamping device 12 swings outwards in the direction of the cross wire or in the direction of the arrow P₈ in order to eliminate any unevenness and waviness in the cross wires. Pretensioning the cross wires also avoids asymmetries in the finished grid web due to thermal stresses during welding. The clamping force is set according to the respective strength values of the cross wires. When using a hydraulic cylinder as a clamping cylinder 21, this is done, for example, by correspondingly controlling the hydraulic pressure.

As is apparent from Fig. 2, the clamping device 11 consists of an upper jaw 23, 23 'and a lower jaw 24, 24'. The upper jaw 23, 23 'has on its side facing the nozzle block 2 a cutting edge, which makes it possible, in cooperation with a cutting edge on the outlet side of the nozzle block 2 during the feeder movement of the arms 8, 9, to cut off the transverse wires Q, Q' from the wire supply . The clamping device 12 of the feeder arm 9 consists of an upper jaw 25, 25 'and a lower jaw 26, 26'. The upper jaws 23, 23 'and 25, 25' each have a plurality of recesses which are adapted in their dimensions to the cross wire diameter and correspond in their lateral spacing to the smallest possible basic pitch a of the cross wires.

The lower jaws 24, 24 '; 26, 26 'point across to the weft direction P₂ running serrations or knurls to increase the frictional engagement between the jaws and the cross wires Q, Q '.

To avoid shunts when welding the two transverse wires Q, Q 'to the longitudinal wires L, the clamping jaws each consist of a front part 23', 24 ', 25', 26 'in the longitudinal wire feed direction and of a rear part 23, 24, 25, 26, which each take up only one cross wire and are electrically insulated from each other by an insulation 27 and additionally from the holders of the clamping jaws in the feeder arms 8, 9.

The cross wire feed is done after completion of a weld as follows: The clamping device 11 is opened by lowering the lower jaw parts 24, 24 'with the aid of a clamping lever 30 operated by a clamping drive 28 and a clamping cylinder 29 in the direction of arrow P₉. At the same time, the clamping device 12 is opened by lowering the lower jaw parts 26, 26 'in the direction of arrow P₉ with the aid of a clamping lever 32 actuated by a clamping cylinder 31. When the clamping jaws 25, 26 are opened, the clamping lever 22 completes its movement in the direction of the arrow P₈ and brings the clamping jaws 25, 26 into the end position shown in broken lines in FIG. 2. Subsequently, the clamping devices 11, 12 are transferred together into the takeover positions K, K '. The upper jaws move on the trajectories O, O 'shown in Fig. 2, whereas the lower jaws are guided on the trajectories O, O' substantially parallel trajectories, which, however, are not shown in Fig. 2 for clarity .

After reaching the takeover positions K, K ', the clamping devices 11, 12 are closed in order to securely clamp the cross wires Q, Q'. The closing movement in the direction of arrow P₁₀ is caused by the lower jaws 24, 24 'and 26, 26', which is operated by means of the clamping lever 30 actuated by the clamping drive 28 and the clamping cylinder 29 or by means of the clamping cylinder 31 operated clamping lever 32 is executed.

As shown in Fig. 3a, the welding current from transformers and busbars, not shown, is supplied by means of a power supply 33 to a top electrode 34 in the direction of production P 1 and initially flows over the rear welding spot formed by the longitudinal wire L and the rear cross wire Q into a rear lower electrode 35, from there either directly (Fig. 3b) or via electrically conductive electrode spacers 36, 36 '(Fig. 3a) in the front lower electrode 35', then over the front, formed by the longitudinal wire L and the front cross wire Q ' Welding point in a front upper electrode 34 'to finally be derived via a power supply 33' to corresponding busbars.

The lower electrodes 35, 35 'and the electrode spacers 36, 36' are removably attached in a lower electrode holder 37. The two upper electrodes 34, 34 'are electrically separated from one another by insulation 38. The lower electrodes 35, 35 'are fixed during the welding process, while the upper electrodes 34, 34' can be moved with the aid of an electrode bar 39 in accordance with the double arrow P 1 and can thus be acted upon with the required welding pressure. The upper electrodes 34, 34 'can each be individually adjusted with respect to their welding pressure to the dimensions of the longitudinal and transverse wires to be welded by means of an adjusting screw 40 and an electrode spring 41.

3a and 3b schematically possible welding positions AG for the cross wires Q, Q 'are shown, each corresponding to a multiple of the smallest possible basic pitch a. When producing grid tracks with the smallest possible basic pitch a, the welding positions AB are assumed. Here, a slightly modified, front upper electrode 34 'with a dash-dotted cutout is used to avoid re-welding of the already welded cross wire Q' located in position D. Will one Cross wire division with twice the value of the basic pitch a is required, so either the welding positions AD or CB can be adopted. The welding position CD corresponds to three times the value of the basic pitch a.

In the welding positions described above, the two sub-electrodes 35, 35 'are arranged adjacent, as shown in Fig. 3b. The welding positions E-D define four times the smallest possible basic pitch a. If five times the basic pitch a is desired, the welding positions F-D or E-G can be adopted. The welding position F-G allows cross wire division with six times the spacing of the basic pitch a. As shown in Fig. 3a, the lower electrodes 35, 35 'are separated by the electrode spacers 36, 36' in the latter welding positions.

To set the exact orthogonality between the cross wires Q, Q 'and the longitudinal wires L, the tilting shaft 14 can be adjusted on one side in the production direction P 1 by means of an eccentric adjustment 43 which can be adjusted via an adjusting spindle 42. In addition, the positioning bar 19 can also be adjusted with the aid of an adjusting eccentric 44 to the exact orthogonality of the cross wires Q, Q 'to the longitudinal wires L.

When changing the cross wire division to a multiple of the smallest possible basic division a, the corresponding feed nozzles of the nozzle block 2 are loaded, and the plate carriers 5, 5 'and the valve shafts 6, 6' are set in accordance with the double arrow P 12. At the same time, as shown in FIGS. 3a and 3b, the sub-electrodes 35, 35 'and the electrode spacers 36, 36' are to be exchanged in their positions. Should the smallest possible basic division a be changed in principle, i.e. e.g. from a 1-inch basic pitch to a 20-mm basic pitch, for example, both the nozzle block 2, the clamping device 11, the clamping device 12 and the positioning arms 17, 17 'are completely replaced.

Claims (13)

1. Welding machine for producing mesh of longitudinal and cross wires (L,Q,Q′) crossing one another at right angles and welded at the points of intersection, having a device for feeding the longitudinal wires (L) in a horizontal welding plane, two devices arranged at a mutual distance apart on insertion lines (K,K′) and intended for simultaneously inserting two cross wires (Q,Q′), a welding-electrode arrangement (33-37,33′-36′) for carrying out a double spot weld in the direction of the longitudinal wires (L), and two feeder arms (8,9) for transferring the cross wires (Q,Q′) from the insertion lines (K,K′) to the welding lines (S,S′), the feeder arms (8,9) being arranged outside the outer longitudinal wires (L) and being moveable in a reciprocating manner on predetermined paths of movement between the insertion lines (K,K′) and the welding lines (S,S′) by means of a common feeder-arm support (10) running perpendicularly to the longitudinal-wire direction, characterised in that the feeder arms (8, 9) are designed to receive both cross wires (Q, Q′) together and are equipped with clamping devices (11, 12) for the cross wires (Q, Q′), in that at least one of the feeder arms (8, 9), in order to pretension both cross wires (Q, Q′) together relative to the other feeder arm, can be moved with adjustable tension force in the cross-wire direction by means of an actuator (22), and in that positioning members (17, 17′) pivotable in the area of the welding lines (S, S′) are provided for the exact positioning of the cross wires (Q, Q′) in accordance with the preset cross-wire spacing.
2. Welding machine according to Claim 1, characterised in that at least one (9) of the feeder arms is arranged on the feeder-arm support (10) in such a way as to be displaceable relative to the other feeder arm (8) for the positioning.
3. Welding machine according to Claim 1 or 2, characterised in that the positioning members are formed by arms (17, 17′) which project from a pivot member (19) extending over the machine width and are provided in the area of their free ends with catch recesses for the cross wires.
4. Welding machine according to one of Claims 1 to 3, characterised in that the paths (U, U′) of movement of the feeder arms (8, 9) for the cross wires (Q, Q′) from the insertion lines (K, K′) to the welding lines (S, S′) and the paths of movement (O, O′) for the return movement are each composed of a feed stretch (P₅) and a rocking-movement stretch (P₆).
5. Welding machine according to one of Claims 1 to 4, characterised in that the clamping devices (11, 12) for the cross wires (Q, Q′) have bottom clamping jaws (24, 24′; 26, 26′) which can be opened and closed and interact with allocated top clamping jaws (23, 23′; 25, 25′) and in that the top clamping jaws (23, 23′; 25, 25′) are each provided with a plurality of catch recesses for receiving the cross wires, the distance between which corresponds to the preset smallest cross-wire spacing (a).
6. Welding machine according to Claim 5, characterised in that the top clamping jaw (23, 23′) of the clamping device (11) on the feed side forms a cutting tool, and in that at least two cross-wire feeds are provided in a nozzle block (2) on the feed side, the delivery side of which nozzle block (2) has a cutting edge for interacting with the top clamping jaw (23, 23′), forming the cutting tool, of the clamping device (11) on the feed side in order to separate the cross wires (Q, Q′) from the wire supply.
7. Welding machine according to Claim 6, characterised in that the bottom clamping jaw (24, 24′) of the clamping device (11) on the feed side can be actuated by a clamping lever (30) which can be acted upon by means of a clamping cylinder (29) and a clamping drive (28), and in that the bottom clamping jaw (26, 26′) of the clamping device (12) remote from the feed side can be actuated relative to the allocated top clamping jaw (25, 25′) by a clamping lever (32) which can be actuated by means of a clamping cylinder (31).
8. Welding machine according to one of Claims 5 to 7, characterised in that the clamping jaws (23, 23′; 24, 24′; 25, 25′; 26, 26′) of the clamping devices (11, 12) each consist of a front part (23′, 24′; 25′, 26′) in the longitudinal-wire feed direction (P₁) and a rear part (23, 24, 25, 26) which are separated from one another by insulation (27).
9. Welding machine according to one of Claims 6 to 8, characterised in that the distances between the wire feeds in the nozzle block (2) as well as the distances between the catch recesses in the positioning members (17, 17′) and in the top clamping jaws (23, 23′; 25, 25′) correspond to the smallest possible basic spacing (a) of the cross-wire spacing.
10. Welding machine according to one of Claims 1 to 9, characterised in that the feeder arm (9) remote from the feed side can be pivoted in the cross-wire direction (Q, Q′) by means of the actuator (22), the actuator preferably having a tension lever (22) which can be actuated by a hydraulic cylinder (21) which can be loaded with adjustable pressure.
11. Welding machine according to one of Claims 1 to 10, characterised in that the bottom electrodes (35, 35′) can be altered for different welding positions (A-G) of the welding lines (S, S′) (Figs. 3a, 3b).
12. Welding machine according to one of Claims 1 to 11, characterised in that the top electrodes (34, 34′) can be individually set by means of an adjusting screw (40) and an allocated electrode spring (41).
13. Welding machine according to one of Claims 1 to 12, characterised in that the insertion lines (K, K′) are each defined by at least one fixed plate (3, 3′) and a pivotable flap (4, 4′) which define a cross wire guide (R) between them.

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