AT528152A1 - Device for holding wires and method for welding wires - Google Patents

Abstract

The invention relates to a device (1) for holding wires, in particular for holding wires during welding, for example during welding of longitudinal wires of a mesh mat to transverse wires thereof, wherein the device (1) comprises a pair of tongs (2) for holding the wires. In order to bring a wire, in particular a longitudinal wire, into a starting position favorable for welding to another wire such as a transverse wire, the invention provides that the tongs (2) comprise pivotable tong elements (3) and at least one driver (4) for the tong elements (3). The tong elements (3) can be moved essentially linearly with the at least one driver (4) from a starting position into a holding position and, in this position, can be pivoted relative to one another, in particular in a positively guided manner, with the at least one driver (4), in order to hold a wire. The invention further relates to a method for welding wires, in particular using a device (1) according to the invention.

Description

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Device for holding wires and method for welding wires

The invention relates to a device for holding wires, in particular for holding wires during welding, for example during welding of longitudinal wires of a grid mat with transverse wires of the same, wherein the device comprises a

Includes pliers for holding the wires.

Furthermore, the invention relates to a method for welding wires, for example longitudinal wires and transverse wires of a grid mat such as a reinforcement mat, in particular with a device of the type mentioned above,

wherein at least one wire is held with pliers during welding.

When producing mesh mats with longitudinal wires and transverse wires, each made of a single steel, the state of the art involves feeding the longitudinal wires in the direction of production and welding them to transverse wires fed transversely to the direction of production. For welding, welding heads are provided in corresponding devices that are designed to be movable, so that a bundle of longitudinal wires at the same height can be welded to a single transverse wire at different positions. A single welding head that can be moved linearly along a transverse wire may be sufficient for this purpose. A group of welding heads may also be used.

of welding heads, which can only be moved in height.

During the production of mesh mats, the longitudinal wires are provided at an inlet side with a specified pitch, i.e., at a specific distance from each other. However, it may happen that this inlet-side pitch does not correspond to the pitch in the mesh mat, for example, because a different pitch is required on an outlet side or in the mesh mat to optimize static properties.

is desired.

In order to hold the supplied longitudinal wires in a suitable position when welding with a cross wire, it is known from the prior art to use V-shaped components such as angle plates, which are usually arranged on the welding head. Due to the V-shape, the longitudinal wires can be positioned in a suitable position, regardless of their diameter.

a specific position before the welding process begins. The V-shaped

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Components are usually actuated via pneumatic cylinders. Although angle plates, for example, allow flexibility in terms of diameter, a disadvantage is that this results in a relative movement of the longitudinal wires relative to the V-shaped component, which can lead to friction and damage to the cross wire. Another disadvantage is that without an additional position measuring system, a translation can be initiated, which is detrimental to the product geometry. Finally, the pneumatic cylinders used have a high failure rate, since the forces resulting from the

impact on the product is introduced directly into the pneumatic cylinders.

Devices of the type mentioned above are also known from the state of the art, in which longitudinal wires are gripped and handled with pliers, for example,

However, damage may also occur.

This is where the invention comes in. The object of the invention is to develop a device of the type mentioned at the outset in such a way that a wire, in particular for welding, can be held securely and in a precisely positioned manner, whereby the risk of damage

individual wires is reduced.

A further aim of the invention is to develop a method of the type mentioned in the introduction in such a way that a safe and precise welding of wires is possible,

whereby the risk of damage to individual wires is reduced.

The object of the invention is achieved if, in a device of the type mentioned at the outset, the pliers comprise pivotable pliers elements and at least one driver for the pliers elements, wherein the pliers elements with the at least one driver can be moved essentially linearly from a starting position into a holding position and in this position can be pivoted relative to one another in particular in a positively guided manner in order to

to hold a wire.

According to the invention, the pliers comprise pivotable pliers elements and a driver designed to pivot the pliers elements relative to each other. The device is designed such that the pliers elements, together with the driver, can be moved from a starting position to a holding position.

wherein the movability is at least substantially along a straight line.

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Advantageously, the linear movement of the gripper elements is first completed, after which the gripper elements are moved toward each other to grip and hold a wire, in particular a fed longitudinal wire. Through the sequence of linear movement of the gripper elements and subsequent pivoting of the same, the gripped wire can be gripped safely and precisely and welded. The pivoting of the gripper elements is achieved by at least one driver, which initially moves passively with the gripper elements into the holding position and is then actuated. A risk of damage

of wires is also at least reduced.

In principle, it is also possible for the clamp elements to already pivot or be initiated when the clamp elements are moved linearly. However, for design reasons, performing these steps of moving and pivoting the clamp elements discretely one after the other is preferred. The device is therefore advantageously designed so that the clamp elements can only pivot in the holding position. This ensures that the wire is reliably grasped and can also be released again. An introduced force can be used to first effect the translational movement up to the holding position and then, when the clamp elements can no longer be moved translationally, to initiate and complete the pivoting process. The actuating elements are therefore

protected, as the force introduced into them is low.

Advantageously, the clamp elements are essentially linearly movable, especially vertically, up to a stop. The stop ensures that the clamp elements cannot be moved beyond the holding position. For this purpose, the clamp elements can be connected to a flange, which is to lie against the stop in the holding position.

This blocks further linear movement beyond the stop position.

Although the invention is not limited thereto, the gripper elements generally grip a supplied longitudinal wire, which is, for example, placed on a cross wire and welded to this cross wire, particularly to produce a grid mat from longitudinal wires and cross wires in a horizontal plane. For linear movement, the gripper elements are suitably mounted in the device.

for example, on a block that is on one or more associated

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Guide rods are slidably mounted and carry the flange mentioned.

Pliers elements can be mounted on this block so that they can be pivoted laterally.

To perform the movements of the gripper elements, the device can comprise an actuator with which the gripper elements and/or the driver can be moved and/or with which the gripper elements can be pivoted. The actuator can be an electric or hydraulic actuator, for example, but a pneumatic actuator is preferably provided. A single actuator is sufficient for all movements. When the gripper elements can be moved up to a stop, they are in the holding position. The at least one driver moves along and is mounted between the gripper elements for further movement. Once the stop is reached, the pivoting movement can then follow the vertical movement by the at least one driver being moved further linearly, thus initiating the pivoting movement of the gripper elements. In principle, however, several separately operating actuators can also be provided for different movements.

although this is more complex.

It can be provided, in particular, that the pliers elements have guides which run obliquely with respect to a vertical axis and in which a driver engages, wherein the guides are designed to move the pliers elements towards each other when the driver is moved in the holding position. Preferably, the guides are designed so that pivoting of the pliers elements is achieved by a further linear movement of the driver in the holding position. One driver is then sufficient for one pair of pliers elements. When two or possibly more pairs of pliers elements are arranged, a single driver can actuate several pairs of pliers elements or, in other words, when several

Pliers activate a grip.

It can also be provided that the guides have a length and/or an angle relative to the vertical axis, so that in the holding position, when the clamp elements are pivoted towards each other, the contact surfaces of the clamp elements hold the wire only by friction. In this particularly preferred variant, the wire to be welded can first be clamped by the clamp elements with a clamping force.

be gripped, but during welding only by friction

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held. For this purpose, the clamp elements can be designed with an opening angle downwards relative to the vertical axis, i.e. form a downwardly open V. The clamp elements then remain in position on the wire through friction. Due to the open angle of the clamp elements and the given self-locking, the clamp formed by the clamp elements acts like a guide during welding when the actuator is depressurized, and a change in the longitudinal wire in the direction of gravity (welding depth) can be compensated for during the welding process. This results in welded joints of particularly high quality. In this context, it is particularly preferably provided that the device comprises a preferably pneumatic actuator and a control device, wherein the control device optionally depressurizes the actuator in the holding position when the clamp elements are pivoted towards each other. This makes it possible to initially grip a wire with a predetermined clamping force. For example, the actuator can be subjected to a pressure of several bar. As soon as the wire is grasped in the holding position and ready for welding, the actuator can be depressurized. The clamp elements cannot move due to friction and, in this situation, act as a clamp for the wire to be welded.

as mentioned as a guide without additional force application.

It is also particularly preferred that a single driver is provided for pairs of cooperating pliers elements. In particular, several pairs of cooperating pliers elements can be provided. For example, if two pairs of cooperating pliers elements are provided, a single driver can pivot four pliers elements, so that a total of four pliers elements can be pivoted with one driver and thus two pliers can be actuated. An arrangement of two or possibly more pliers has the advantage that a torque can be introduced into the wire. This allows, in particular,

Nodes crossing at an angle of 90° can be created precisely.

The device can comprise at least one spring that presses the clamp elements into the holding position. The clamp elements can be pivotally mounted on a movable block with a flange. The flange, in turn, can be moved along one or more guide rods from a rest position to the stop.

A spring can be mounted on one of these guide rods, so that when

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This additional spring force ensures that the pincer elements move linearly from the rest position to the stop. This additional spring force ensures that, particularly with pneumatic actuation, the driver does not initiate the pivoting movement before the stop or holding position is reached. Conversely, when opening, the driver is activated first, before the pincer elements move to the starting position by overcoming the opposing spring force.

can be.

The device can further comprise a linearly movable, particularly vertically movable, hold-down clamp. This makes it possible to easily perform double-wire welds with individual, movable welding heads, although double-wire welds are also possible without a hold-down clamp. It should be ensured that a wire to be welded on is not pushed over an already welded wire. Suitable means can be used for this purpose, if necessary, for example, suitably designed guides for the wire to be welded on.

The device can be mounted on a freely moving welding carriage or on a dedicated chassis of a welding system and preferably picks up longitudinal wire transversely to the production direction before welding. The clamp elements are generally designed to handle wires with a diameter of 2 mm to 26 mm.

preferably 4 mm to 20 mm.

However, the use of a device according to the invention is not limited to the welding of wires. Rather, the device according to the invention can also be used, for example, for feeding wires to mesh welding systems or other systems, for example for the inlet-side feeding of longitudinal wires for

Production of mesh mats using a welding device.

Furthermore, a device according to the invention can comprise, for example, a position measuring system for fed longitudinal wires, so that the quality of a weld can be determined. This can also be achieved with other measuring systems, for example a measuring system for

Side currents during welding, which also indicate the quality of the weld.

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In a further aspect, the invention comprises a welding device with a plurality of devices according to the invention, wherein the devices are separated

can be operated from each other.

The further aim of the invention is achieved if, in a method of the type mentioned at the outset, pivotable pliers elements of the pliers are moved from a starting position essentially linearly to a holding position and pivoted in this position,

to hold at least one wire.

A method according to the invention is particularly advantageous in that a wire can be gripped and held in a defined manner during welding. A discrete sequence of linear, particularly vertical, movement of the tong elements and subsequent pivoting of the tong elements ensures a high level of process reliability and allows for safe and precise welding of wires, whereby the risk of damaging a wire is significantly reduced compared to V-shaped

Angle plates are significantly reduced.

A movement of the gripper elements and/or drivers, which are designed to pivot the gripper elements, can be carried out, for example, electrically or hydraulically. Particularly preferably, the gripper elements and/or drivers are initially moved together linearly pneumatically. Once a holding position of the gripper elements has been reached, the drivers can be moved further linearly in order to initiate a pivoting movement of the gripper elements relative to one another. For this purpose, the elongated gripper elements can have lateral guides into which the drivers engage. These lateral guides have an angle relative to the plane along which the driver is moved, in particular pneumatically. This results in a positive guide, which leads to the gripper elements pivoting towards one another and thus gripping a wire when the driver is moved further linearly. The lateral guides of the gripper elements are in this case

Wire diameter and a desired clamping force. Especially if both the clamp elements and the driver(s)

pneumatically operated, it is advantageous if the clamp elements are

linear movement from the starting position to the holding position with a spring force

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The additionally applied spring force ensures that the gripper elements are first moved into the holding position before the driver(s) are actuated. This makes it possible to initiate the pivoting movement only when the holding position for the gripper elements is reached. This can be the case in particular when the holding elements have moved to a stop, against which, for example, a flange connected to the gripper elements strikes. The at least one driver is mounted between the gripper elements and only moves relative to them when the gripper elements no longer move linearly to the

Gripping a wire can be moved.

It is also particularly preferred, and within the scope of the method with a device according to the invention, for the wire to be gripped in the holding position with a clamping force, after which the clamping force is reduced, in particular set to essentially zero, and the wire is held by friction during welding. Thus, the wire to be welded can initially be gripped in the holding position or in a desired welding plane and brought into position. A specific clamping force is provided for this purpose. Once the wire is in this position, the clamping force can be omitted. If the tongs elements form a predetermined angle of less than approximately 5° in relation to the wire diameter when pivoted relative to one another, which results from the pivotability of the tongs elements about a common pivot axis, even when a pneumatic system is depressurized, there is no mobility of the tongs elements due to a self-locking or wedge effect. As a result, the function of the tongs elements during welding with a welding head changes to merely guiding the wire. This results in a particularly high quality of welded joints, since the wire

is welded virtually without additional force.

The sequence of a movement of the linear movement of the gripper elements and the closing takes approximately 200 ms. Due to the provided mechanical positive guidance, position switches and the associated position processing between the two movements can be omitted if the gripper elements and the driver(s) are mechanically positively guided. For this purpose, in particular, a

Device for carrying out the method may be used.

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The method according to the invention can also be used for producing double wire welds, if, for example, a first longitudinal wire is welded to a cross wire in the manner explained, after which another longitudinal wire is grasped with the pliers and placed on the cross wire, after which the pliers elements are closed so that both longitudinal wires are held, after which a hold-down device is lowered onto the longitudinal wires, after which the second

Longitudinal wire is welded to the transverse wire.

Further features, advantages, and effects of the invention will become apparent from the following exemplary embodiments. Reference is made to the drawings, which show:

Fig. 1 is a schematic representation of a device according to the invention and of a welding process;

Fig. 2 is a schematic representation of a method for producing double wire welds;

Fig. 3 is a perspective view of a device according to the invention;

Fig. 4 shows a section through a device according to the invention;

Fig. 5 to Fig. 7 different states when operating a device according to the invention

device.

Fig. 1 shows a highly schematic representation of a device 1 according to the invention and a method using the same. The device 1 comprises a pair of pliers 2 with two

Pliers elements 3. Furthermore, a driver 4 is provided for the two pliers elements 3. The pliers elements 3 are pivotally mounted relative to one another about a pivot axis $S. The pliers elements 3, like the driver 4, are mounted for linear movement along a vertical axis V. As a rule, linear movement along a vertical axis is provided, in particular when a grid mat is produced in a horizontal plane. The pliers elements 3 are connected to the driver 4, wherein the driver 4 engages in the pliers elements 3 such that they are pivotable upon linear movement of the driver 4. Furthermore, an actuator 14 (not shown) is provided, which is designed for the pneumatic actuation of the pliers elements 3 and the driver 4. In addition, a spring 7 is provided, which moves the pliers elements 3 along the arrow shown in Fig. 1.

a stop 5.

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In the starting position A shown in Fig. 1 top left, the actuator 14 initially holds the tongs elements 3 in a starting position A against the spring force by applying a corresponding force. In order to grasp a longitudinal wire L to be welded, a force is applied in the opposite direction via the actuator 14, so that according to the second position in the top row in Fig. 1, an excitation force is produced which acts in the same direction as the spring force. As a result, the tongs elements 3 are moved linearly until they reach a holding position H, because a part connected to the tongs elements 3 rests against a stop 5. The tongs elements 3 cannot then be moved any further. Due to the pneumatic excitation force which is still present, the driver 4 can now be moved linearly and, due to the positively guided connection with the tongs elements 3, closes them or positions the tongs elements 3 towards each other so that they grasp the longitudinal wire L. Thus, the translatory extension of the

Pliers elements 3 a rotational closing of the same by the driver 4.

The spring force exerted by the spring 7 is necessary in this context to prevent that the actuation with the actuator 14 simultaneously initiates a closing movement by the driver 4. The spring force is a

Closing is only possible when stop 5 or holding position H is reached.

The position shown in Fig. 1 in the top row on the far right corresponds to a situation in which the longitudinal wire L is gripped with a clamping force and brought into a welding position. For this purpose, the actuator 14 can be pneumatically pressurized with a pressure of, for example, a few bar. The longitudinal wire L is then in the welding position corresponding to the bottom row, on the far left. In this situation, the actuator 14 can be depressurized. The spring force still acts to hold the tong elements 3 in the welding position. Furthermore, the tong elements 3, in interaction with the driver 4, can be configured in such a way, in particular by a downwardly opening angle, that the tong elements 3 cannot move in this pressure-free situation. The longitudinal wire L is then held only by friction. This is an optimal situation for the subsequent welding process, indicated by the arrow pointing to the longitudinal wire and indicating the pressure from a welding head, which enables the production of

Welded joints of very high quality are permitted. The process then runs

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11

The excitation force of the actuator 14 initially ensures that the driver 4 is moved linearly in the opposite direction, which, due to the positive guidance, leads to an opening of the clamp elements 3. Only when this opening has taken place can the clamp elements 3 be moved back into a

Starting position A must be moved.

Fig. 2 schematically shows an analogous method for producing double-wire welds, comprising steps 1 to 7. In this case, a hold-down device 9 is also required. A longitudinal wire L is placed on a cross wire in the manner explained above and welded to it by means of a movable welding head 10. After the first longitudinal wire L has been welded to the cross wire, the tongs 2 are opened, the welding head 10 is raised and the tongs 2 are raised, and an additional tong takes over a second longitudinal wire L. This second longitudinal wire L is placed on the cross wire next to the first longitudinal wire L. A hold-down device 9 is then lowered onto the two longitudinal wires L so that the second longitudinal wire L cannot be pushed over the first longitudinal wire L. The tongs 2 are then positioned so that both longitudinal wires L are gripped from one side each, and a

Welding of the second longitudinal wire L with the cross wire.

In Fig. 3 and the cross-section according to Fig. 4, a practical embodiment of a device 1 according to the invention can be seen. The device 1 comprises two tongs 2, each with two pairs of tong elements 3. The tong elements 3 are pivotally mounted about a pivot axis S and can be moved linearly between a starting position A and a holding position H. Usually, the device 1 is installed in a welding system such that the tong elements 3 can be moved vertically in order to grasp a longitudinal wire L as explained in Fig. 1 or Fig. 2 and to hold it during welding. The tong elements 3 are connected to a block with a flange 11. The block with the flange 11 can be moved linearly on guide rods 12, up to a stop 5. In the opposite direction, springs 7 are mounted on the guide rods 12, which springs are arranged between the flange 11 and a

Counterpart 13 is clamped.

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The clamp elements 3 are actuated by a pneumatic actuator 14. In the initial position A, the excitation force of the actuator 14 acts against the spring force

by the springs 7, so that the starting position A is maintained.

As can be seen in particular from Fig. 4, the tongs elements 3 are connected to the drivers 4. When two tongs 2 are formed in pairs, each with two tongs elements 3, a single driver 4 is preferably provided for all tongs elements 3. The driver 4 then actuates four tongs elements 3. The tongs elements 3 have lateral guides 6 for this purpose. The guides 6 can be designed as elongated holes as shown, although other types of guides 6 are also possible. Extensions of the driver 4 engage in the guides 6. This means that during a linear movement of the driver 4, due to the positive guidance, the tongs elements 3 are only mechanically pivoted about the pivot axis S

be swiveled.

5 to 7 show various operating states, as explained with reference to the schematic representation in Fig. 1. Fig. 5 corresponds to a situation in which the tongs elements 3 are in a starting position A. A force applied by the actuator 14 counteracts a spring force of the springs 7. If the actuator 14 is now actuated in such a way that a force acts in the other direction, the force of the actuator 14 together with the spring force of the springs 7 ensure that the tongs elements 3 are moved linearly until the flange 11 comes to rest on the stop 5. The drivers 4 are not actuated during this linear movement, but rather the state according to Fig. 6, thus the holding position H, is reached first. Only when this holding position H is reached can the drivers 4 move linearly and, due to the positive guidance in the guides 6 of the tongs elements 3, ensure the desired pivoting of the same and thus the gripping of a longitudinal wire L. The longitudinal wire L is then grasped and is in a suitable welding position. In this welding position, the actuator 14 can then be depressurized, so that, with a suitable design of the guides 6, the longitudinal wire L is held against the contact surfaces 8 of the gripper elements 3 only by friction, preventing movement of the gripper elements 3. A downwardly open angle formed by the contact surfaces 8

of less than 5° is indicated by dashed lines in Fig. 7. The longitudinal wire L is then

in an optimal starting situation A for the production of high-quality

Welded joints.

A device 1 according to the invention has, among other things, the advantage that it is very simply designed with only a single actuator 14 and, due to the provided forced guidance between the pliers elements 3 and the driver 4 as well as the spring forces by the springs 7 and a discrete sequence of linear movements and pivoting movements in the application, a high-quality production of

Welded joints are possible.

Claims (15)

15 20 25 30 14 patent claims 1. Device (1) for holding wires, in particular for holding wires during welding, for example during welding of longitudinal wires (L) of a grid mat with transverse wires thereof, wherein the device (1) comprises a pair of pliers (2) for holding the wires, characterized in that the pliers (2) comprise pivotable pliers elements (3) and at least one driver (4) for the pliers elements (3), wherein the pliers elements (3) with the at least one driver (4) can be moved essentially linearly from a starting position (A) into a holding position (H) and in this with the at least one driver (4) in particular are forcibly pivoted towards each other in order to hold a wire. 2. Device (1) according to claim 1, characterized in that the Pliers elements (3) can only be pivoted in the holding position (H). 3. Device (1) according to claim 1 or 2, characterized in that the pliers elements (3) are substantially linear, in particular vertical, up to a stop (5) are movable. 4. Device (1) according to one of claims 1 to 3, characterized in that the device (1) comprises an actuator with which the pliers elements (3) and/or the driver (4) can be moved and/or with which the pliers elements (3) are pivotable. 5. Device (1) according to one of claims 1 to 4, characterized in that the pliers elements (3) have guides (6) which run obliquely with respect to a vertical axis (V) and in which a driver (4) engages, wherein the guides (6) are arranged, when the driver (4) is moved in the holding position (H) To move the pliers elements (3) towards each other. 6. Device (1) according to claim 5, characterized in that the guides (6) have a length and/or an angle relative to the vertical axis (V) such that in the holding position (H) with the pliers elements (3) pivoted towards each other Contact surfaces (8) of the pliers elements (3) hold the wire by friction. 15 20 25 30 15 7. Device (1) according to one of claims 1 to 6, characterized in that the device (1) comprises a preferably pneumatic actuator (14) and a control device, wherein the control device controls the actuator (14) and wherein the control device holds the actuator (14) in the holding position (H) at pivoted pliers elements (3) can be switched off optionally without pressure. 8. Device (1) according to one of claims 1 to 7, characterized in that a single driver (4) for pairwise cooperating pliers elements (3) is intended. 9. Device (1) according to one of claims 1 to 8, characterized in that several pairs of cooperating pliers elements (3) are provided. 10. Device (1) according to one of claims 1 to 9, characterized in that the device (1) comprises at least one spring (7) which urges the pliers elements (3) in presses the hold position (H). 11. Device (1) according to one of claims 1 to 10, characterized in that the device (1) has a linearly movable, in particular vertically movable, Hold-down device (7). 12. Device (1) according to one of claims 1 to 11, characterized in that the pliers elements (3) are arranged to clamp wires with a wire diameter from 2 mm to 26 mm, preferably 4 mm to 20 mm. 13. Welding device with a plurality of devices (1) according to one of the Claims 1 to 12, wherein the devices (1) can be operated separately from one another. 14. Method for welding wires, for example longitudinal wires (L) and transverse wires of a mesh mat such as a reinforcement mat, in particular with a Device (1) according to one of claims 1 to 12, wherein at least one wire is held during welding with a pair of pliers (2), characterized in that pivoting pliers elements (3) of the pliers (2) from a starting position (A) in Essentially linearly moved to a holding position (H) and swiveled in this to hold at least one wire. 15. Method according to claim 14, characterized in that the pliers elements 5 (3) and/or drivers (4) for pivoting the pliers elements (3) are pneumatically linear be processed. 16. Method according to claim 14 or 15, characterized in that the clamp elements (3) during the linear movement from the starting position (A) in 10 the holding position (H) is subjected to a spring force. 17. Method according to one of claims 14 to 16, characterized in that the wire is gripped in the holding position (H) with a clamping force, after which the clamping force is reduced and the wire is held by friction during welding 15 will be.