EP2897744B1 - Device and method for automatically twisting metal wires, in particular for connecting adjacent, preferably mutually intersecting structure elements - Google Patents

Description

The present invention relates to a device for automatically twisting metal wires, in particular for connecting adjacent, preferably crossing, structural elements. In the context of the invention, a structural element is understood to mean an elongate body which has a round or polygonal, for example quadrangular, cross section. Examples of such structural elements are, for example, tubes, rods or carriers, as they are widely used in all sectors of industry. Also covered by the term structural element are wire rope bundles, so-called strands, or prestressing strands, which are used inter alia for the production of reinforcing baskets for prestressed concrete elements.

A typical application for devices of the type mentioned is the production of such reinforcing cages, for example. For prestressed concrete elements. Reinforcing baskets have a latticed structure of (steel) strands. The lattice-like structure is achieved by interposing strands in a first direction and strands in a second direction crossing each other. In the area in which they intersect, the so-called twisting area, the position of the strands is fixed to each other by means of a metal wire. The metal wire is wrapped around the twist portion of the strands, forming a loop. The two ends of the Wires are then twisted against each other several times until the loop of the wire is sufficiently narrow to fix the two crossing strands or generally the intersecting structural elements to each other.

As an alternative to a crossing arrangement of a plurality of structural elements, generally adjacent structural elements are often fastened by means of twisting wires around the adjacent structural elements. The procedure, with the exception of the other orientation of the structural elements, essentially takes place as described above.

For example, since reinforcing baskets consist of a plurality of strands and consequently a large number of twisting areas is present, many wires have to be twisted for the production of a reinforcing basket. So far, this is done exclusively in manual work. Since the wires to be used for twisting must also have a certain stability, this action is exhausting for the corresponding persons and also very time-consuming. Due to the manual nature of the twist, unevenly twisted wires also occur. Although this is not serious from the point of view of quality assurance due to the large number of twists made, a higher repeatability in twisting wires over adjacent, preferably crossing structural elements would be desirable.

Out WO 96/00135 A1 a device according to the preamble of claim 1 is known.

Accordingly, the present invention has the object to provide an apparatus and a method which overcome the disadvantages described above.

The invention solves the underlying object in a device of the type mentioned in that it is designed according to the features of claim 1. The invention solves the problem in particular by providing a device for automatic twisting of metal wires, in particular for connecting adjacent, preferably crossing structural elements, with a wire feeder for feeding wire, preferably endless wire, into the device, a wire guide arc which selectively releases one and closable opening and is adapted to guide the supplied wire in the closed position along the wire guide arc from a first side of the wire guide arc to a relative to the opening opposite second side of the wire guide arc, a Zugschlitten, which is adapted to the supplied Detecting wire on the first side of the wire guide arc and with the wire guide bow closed along the wire guide arc to the second side of the wire guide arc pull and a twisting unit, which is adapted to detect the supplied wire on both sides of the wire guide arc and to twist by means of a rotary motion.

Advantageous embodiments and preferred embodiments and embodiment of the invention will become apparent from the dependent claims and the description below.

The invention makes use, in particular, of the finding that an automation of twisting contributes significantly to fatigue-free work, since in particular twisting is cumbersome.

However, the invention goes further still further by providing a device which also allows the wire to be passed around the twisting area of two or more adjacent, preferably intersecting structural elements, thereby achieving a significant acceleration of the overall operation. The interplay of automated wire-routing and automated twisting is based on the following guiding principles: The wire is moved along a wire guide arc to ensure a high repeat accuracy with regard to looping through the wire. In order to be able to arrange the wire guide arc, which is formed on the device in the twisting area enclosing manner, an opening of the wire guide arc is provided. This allows even in difficult to access Verdrillungsbereichen, as can be found, for example, reinforcement cages for prestressed concrete components, a simple approximation of the device to the Verdrillungsbereich, embracing the Verdrillungsbereiches with an open wire guide arc and enclosing the Verdrillungsbereiches by closing the opening. The operation is similar to a pair of pliers, for example. Furthermore, the invention is characterized in that the wire along the wire guide arc is pulled by the Zugschlitten. The inventive design of a pulling guide the wire along the wire guide arc is applicable to soft wires that allow better twisting than wires made of hard material .. The device of the invention thus allows by opening and closing the wire guide arc, the wire guide arc to the twisting region of two structural elements The movable pulling carriage then makes it possible to guide the wire fed on one side of the wire guide arc around the twisting area along the wire guide arc with the wire guide bow closed. Finally, the twisting unit can then handle the wire wound around the twisting area of the pulling carriage detect both sides of the twisting region or on both sides of the wire guide arc and, for example by means of a rotary drive, perform the twisting.

Preferably, the wire guide arc is tongs-like, and the selectively releasable and closable opening is proximal to the device. In this case, "proximal" is understood - with reference to the operating orientation of the device - to be the end of the device facing the structural elements to be connected.

The invention is advantageously further developed in that the twisting unit has a first wire feedthrough hole and a second wire feedthrough hole, wherein the wire feed is adapted to feed the supplied wire through the first wire feedthrough hole. Thus, even when feeding the wire in the direction of the wire guide arc, the later detection of the wire by the twisting unit can be prepared. By passing through the feedthrough hole, the wire is already detectable by the twisting unit.

More preferably, the pulling carriage is configured to pass the wire drawn toward the second side of the wire guide arc through the second wire passing hole such that the wire forms a loop from the first to the second through hole. The advantage of this embodiment is in particular the preparation of the detection by the twisting unit on the second side of the wire guide arc in one operation by means of the pull slide in guiding the wire along the wire guide arc. As soon as the loop is formed by the wire, it is immediately inserted and guided into the second wire feed-through hole of the twisting unit.

In a preferred embodiment, the device according to the invention comprises a clamping device, which is preferably arranged on the first or second side of the wire guide arc and which is arranged for holding the wire passed through the first wire feedthrough hole or for holding the wire passed through the second wire feedthrough hole. In particular, the clamping device is adapted to fix the wire after forming the loop over the twisting region of the two structural elements, so that the twisting can be further prepared by the twisting unit.

Further preferably, the device according to the invention comprises a drive means for wire conveying, wherein the drive means is adapted to promote the carried out by the second wire feedthrough hole, held by the clamping device wire to shorten the loop formed to a predetermined extent. When twisting the detected wire by means of the twisting unit, the distance between the constriction produced by the twist and the structural elements to be twisted decreases with each revolution. In order to achieve a sufficient fixation of the structural elements, a certain minimum number of twists is required. On the other hand, in order to achieve as little wire consumption as possible, the number of twists carried out should not exceed a maximum amount. Therefore, it is preferable to limit and define the distance between the twisting unit and the structural members by shortening the wire loop before twisting. It has been found to be particularly preferable to set a loop length which leaves a clearance between the twisting unit and the structural members to be connected which corresponds to the gauge between the first wire penetrating hole and the second wire penetrating hole.

As a reference point for the twisting unit, in determining the distance, the plane in which the points at which the wire on the first and second sides of the wire guide arc is grasped by the twisting unit is assumed. This plane is preferably perpendicular to the axis of rotation of the twisting unit.

It is alternatively preferred to assign the drive means of the wire feed, wherein the drive means is adapted to promote the wire either in the feed direction or counter to the feed direction. The conveying direction is primarily dependent on which of the two sides of the wire guide arc, the clamping device is arranged and holds the wire.

According to a further preferred embodiment, the drive means on a drive member which is driven by a motor and is coupled to the Zugschlitten such that the Zugschlitten selectively from the first side of the wire guide arc to the second side of the wire guide arc out and from the second side of the wire guide arc to the first side of the wire guide bow is movable. According to a further preferred embodiment, the twisting unit has two gear wheels arranged coaxially with one another through which the first and second feedthrough holes extend completely through each other and wherein the two gear wheels can be driven both in opposite directions and in the same direction. Preferably, the two coaxially arranged gears are arranged directly adjacent to each other. An opposite driving of the two gears preferably causes jamming of the wire passing through the first and second wire penetrating holes. This allows the detection of the wire by the twisting unit. The drive is preferably realized by means of a servo motor.

As soon as a sufficient clamping of the wire has been achieved by the counter drive of the gears, the two gears are preferably drivable in the same direction, in such a way that the clamping is maintained while the gears rotate in synchronism to the twist by means of a rotation of the two Wire feedthrough holes around a common axis of rotation bring about.

Further preferably, the device according to the invention comprises a cutting body, which is arranged for separating the wire within the device and adapted to separate the wire on the first side of the wire guide arc and / or on the second side of the wire guide arc. In this way, the separation of the wire is made possible before twisting, without having to carry separate cutting tools with him. The device according to the invention thus permits, in a single, continuous operation, the feeding of wire, wrapping of the wire around a composite of structural elements to be twisted, separation of the twisted wire section from a feed-side wire section, and finally twisting of the wire.

The cutting body is preferably formed as a sharp-edged cutting edge within the device, which is arranged adjacent to the wire passed through the device. Preferably, one or both of the gears of the twisting unit have the cutting edge (s) which is or are formed on the one or more gears such that the separation takes place when the twisting movement begins.

• Bereitstellen von zwei oder mehreren benachbarten, vorzugsweise sich überkreuzenden Strukturelementen,
• Zuführen des Drahtes in eine Vorrichtung nach einer der weiter oben beschriebenen bevorzugten Ausführungsformen,
• Durchführen eines Kreuzungsbereichs der Strukturelemente durch die freigegebene Öffnung des Drahtführungsbogens der Vorrichtung,
• Schließen der Öffnung des Drahtführungsbogens, so dass der Verdrillungsbereich der Strukturelemente von dem Drahtführungsbogen eingeschlossen ist,
• Erfassen des zugeführten Drahtes mittels des Zugschlittens
• Ziehen des zugeführten Drahtes mittels des Zugschlittens bei geschlossenem Drahtführungsbogen entlang des Drahtführungsbogens von der ersten Seite des Drahtführungsbogens zu der bezogen auf die Öffnung gegenüberliegenden zweiten Seite des Drahtführungsbogens,
• Erfassen des zugeführten Drahtes auf beiden Seiten des Drahtführungsbogens mittels der Verdrilleinheit, und
• Verdrillen des erfassten Drahtes mittels einer Rotationsbewegung der Verdrilleinheit.

The invention further relates to a method for automatically twisting a metal wire for connecting two or more adjacent, preferably themselves crossing structural elements. The invention solves the underlying task mentioned in such a method with the following steps:

• Providing two or more adjacent, preferably crossing, structural elements,
• Feeding the wire into a device according to one of the preferred embodiments described above,
• Passing a crossing region of the structural elements through the released opening of the wire guide arc of the device,
• Closing the opening of the wire guide arc so that the twist region of the structural elements is enclosed by the wire guide arc,
• Detecting the supplied wire by means of the Zugschlittens
• Pulling the supplied wire by means of the pulling carriage with the wire guide bow closed along the wire guide arc from the first side of the wire guide arc to the opposite side of the wire guide arc relative to the opening
• Detecting the supplied wire on both sides of the wire guide sheet by means of the twisting unit, and
• Twisting the detected wire by means of a rotational movement of the twisting unit.

With regard to the underlying findings and advantages according to the invention, reference is made to what has been said above with reference to the device according to the invention.

• Durchführen des zugeführten Drahtes durch ein erstes Drahtdurchführungsloch der Verdrilleinheit, vorzugsweise mittels der Drahtzuführung der Vorrichtung,
• Durchführen des zu der zweiten Seite des Drahtführungsbogens hingezogenen Drahtes durch ein zweites Drahtdurchführungsloch der Verdrilleinheit derart, dass der Draht eine Schlaufe von dem ersten zu dem zweiten Drahtdurchführungsloch um die Strukturelemente herum bildet.

The method according to the invention is preferably developed by the detection of the supplied wire by means of a twisting unit comprising one or both of the steps:

• Passing the supplied wire through a first wire feedthrough hole of the twisting unit, preferably by means of the wire feed of the device,
• Passing the wire drawn toward the second side of the wire guide arc through a second wire feedthrough hole of the twisting unit such that the wire forms a loop around the structural members from the first to the second wire feedthrough hole.

• Festhalten des durch das erste Drahtdurchführungsloch durchgeführten Drahtes oder des durch das zweite Drahtdurchführungsloch durchgeführten Drahtes mittels einer Klemmeinrichtung der Vorrichtung.

Further preferably, the method comprises the step:

• Holding the wire passed through the first wire feed-through hole or the wire passed through the second wire feed-through hole by means of a clamping device of the device.

• Fördern des durch das zweite Drahtdurchführungsloch durchgeführten, von der Klemmeinrichtung festgehaltenen Drahtes derart, dass die gebildete Schlaufe auf ein vorbestimmtes Maß zu verkürzt wird.

According to a preferred embodiment of the method, this further comprises the step:

• Conveying the wire passed through the second wire feed-through hole and held by the clamper such that the loop formed is shortened to a predetermined extent.

• ein gegenläufiges Antreiben von zwei koaxial angeordneten Zahnrädern, durch welche sich das erste und zweite Drahtdurchführungsloch jeweils vollständig hindurch erstrecken, derart, dass der durchgeführte Draht geklemmt wird, und

wobei der Schritt des Verdrillens des erfassten Drahtes mittels einer Rotationsbewegung der Verdrilleinheit umfasst:

• ein gleichläufiges Antreiben der beiden Zahnräder mit geklemmtem Draht.

Further preferably, in the method according to the invention, the step of detecting the supplied wire on both sides of the wire guide arc by means of the twisting unit comprises:

• oppositely driving two coaxially arranged gears through which the first and second wire penetrating holes respectively extend completely therethrough such that the passed wire is clamped, and

wherein the step of twisting the detected wire by means of a rotational movement of the twisting unit comprises:

• a co-driving of the two gears with clamped wire.

• Trennen des verdrillten Drahtes auf der ersten und/oder auf der zweiten Seite des Drahtführungsbogens mittels eines Schneidkörpers innerhalb der Vorrichtung.

Further preferably, the method according to the invention comprises the step:

• Separating the twisted wire on the first and / or on the second side of the wire guide arc by means of a cutting body within the device.

The invention further relates to the use of a device according to one of the preferred embodiments described above for the automatic twisting of metal wires, in particular for connecting adjacent, preferably crossing structural elements, for producing a reinforcement cage for a tower element of a wind turbine. The device has in particular:
a wire feed for feeding wire, preferably endless wire, into the apparatus, a wire guide sheet having a selectively openable and closable opening and adapted to move the supplied wire in the closed position along the wire guide arc from a first side of the wire guide sheet to a wire guide arc; relative to the opening opposite the second side of the wire guide arc, a pulling carriage adapted to catch the supplied wire on the first side of the wire guide arc and pull it towards the second side of the wire guide arc, and a twisting unit adapted thereto is to detect the supplied wire on both sides of the wire guide arc and to twist by means of a rotary motion. In this case, the reinforcing cage has, as the first and second structural elements, a plurality of first and second prestressing strands which are arranged to cross one another. The tension strands can optionally be intertwined, which is the Positioning the tensioning strands before twisting the wire facilitates and increases the stability of the basket.

The advantages of the above developments and preferred embodiments of the device according to the invention also apply to the developments and preferred embodiments of the method according to the invention and the development of the use according to the invention.

• Fig. 1 eine räumliche Ansicht einer erfindungsgemäßen Vorrichtung zum Verdrillen von Metalldrähten,
• Fig. 2 eine Seitenansicht der Vorrichtung gemäß Fig. 1 in einem anderen Betriebszustand,
• Fig. 3 eine Seitenansicht der Vorrichtung gemäß Fig. 1 in teilweiser Schnittdarstellung und
• Fig. 4 eine teilweise transparente räumliche Darstellung eines Ausschnitts der Vorrichtung gemäß Fig. 1.

The invention will be described in more detail below with reference to the accompanying figures and with reference to an embodiment. Hereby show:

• Fig. 1 a spatial view of a device according to the invention for twisting metal wires,
• Fig. 2 a side view of the device according to Fig. 1 in another operating state,
• Fig. 3 a side view of the device according to Fig. 1 in partial sectional view and
• Fig. 4 a partially transparent spatial representation of a section of the device according to Fig. 1 ,

In Fig. 1 a device 1 for automatically twisting metal wires is shown. The device 1 has a base body 3. On the main body 3, a wire guide sheet 5 is arranged at a proximal end of the device 1. The wire guide sheet 5 has a substantially centrally disposed between a first side 9 of the wire guide sheet 5 and a second side 11 of the wire guide sheet 5 closable and releasable opening 7.

In the embodiment shown, the first side 9 of the wire guide arc is fixed relative to the base body 3, while the second side 11 of the wire guide arc 5 is deflectable by means of a lever kinematics 15 such that the opening 7 of the in Fig. 1 shown closure position is moved to a release position ( Fig. 2 ). The lever kinematics 15 is driven by a pneumatic cylinder 17 in the embodiment shown.

The wire guide arc 5 is formed substantially like a pliers and has in the interior of the two sides 9, 11 of the wire guide arc a region 27 for receiving adjacent, preferably crossing structural elements.

The wire guide arc 5 has a substantially 13 extending along the entire arc slot. The slot 13 divides the first side 9 of the wire guide arc into two partial arches 9a, 9b. in an analogous manner, the slot 13 divides the second side 11 of the wire guide arc 5 into two partial arcs 11a, 11b.

The slot 13 is adapted to receive a pull slide 23 which is movable along the wire guide arc and guided by a guide groove 29 disposed inside the wire guide arc.

At a wire guide arc 5 opposite end of the region 27, a twisting unit 25 is arranged. The twisting unit 25 is adapted to receive and grasp the wire guided along the wire guide arc 5 and is further adapted to twist it by rotation about a rotation axis X.

At a wire guide arc 5 opposite, distal end of the base body 3, a drive chain 19 is arranged, which extends partially from the housing or base 3 of the device 1 out. The drive chain has a plurality of guide pins 21 which are adapted to stabilize and guide the drive chain 19 under shear load.

With respect to the other figures, the same reference numerals are given for similar or identical elements. With regard to the description of these elements, reference is therefore made to the other figures in each figure. In the in Fig. 2 shown state, the wire guide arc 5 is brought by lateral pivoting of the second side 11 of the wire guide arc in a position in which the opening 7 of the wire guide arc 5 is released. The opening allows embracing two or more adjacent, preferably crossing structural elements, for example two or more tension strands to twist them.

In the in Fig. 2 shown operating state is also the Zugschlitten 23 a piece along the first side 9 of the wire guide arc 5 method towards the second side 11 of the wire guide arc 5 out.

Fig. 3 allows a view of the interior of the device 1. The wire to be twisted is fed in a plurality of supply channels 31a, 31b by means of a drive means 49 in the direction of the wire guide sheet 5. The drive means 49 has a piston 50, which deflects a first coupling member 52 and a second coupling member 53 in such a way that a clamping member 51, through which the wire is also passed, clamps it to the drive means 49. As a result, a promotion of the wire in the feed direction and counter to the feed direction is possible.

The pulling carriage 23 is coupled to the drive chain 19. The movement of the drive chain 19 in both drive directions is ensured by means of a drive pinion 33, which is arranged drivable on the base body 3 of the device. By appropriate drive of the drive chain 19 of the pull slide 23 is guided by means of the groove 29 and from the in Fig. 3 shown position along the wire guide arc on the opposite second side 11 of the wire guide arc 5 moves. This is preferably done when the pull slide 23 has detected the wire in a clamping device 41 and clamped.

The twisting unit 25 ( Figures 3 . 4 ) has two coaxial with each other and immediately adjacent gears 37, 39, through which in each case completely a first wire feedthrough hole 43 and a second wire feedthrough hole 45 extends completely therethrough. The first and second wire feedthrough hole 43, 45 are preferably arranged diametrically opposite to the axis of rotation of the two gears 37, 39 and adapted to receive the wire. The wire is passed through the first wire feedthrough hole 43 on the first side 9 of the wire guide sheet 5 by means of the drive means 49 and passed through the second wire feedthrough hole 45 by the pull slide 23 on the second side 11 of the wire guide sheet 5. In a completed state (through the second wire feedthrough hole 45), a second clamping device 46 is adapted to clamp the wire, thereby shortening the loop by conveying the wire back through the drive means 49 when moving back from the second side 11 of the wire guide sheet 5 in the direction of the first Page 9 can be done. The drive and further details of the twisting unit 25 are also in Fig. 4 shown.

The clamping device 41 of the pulling carriage 23 is preferably designed such that a first slide 36 for detecting and clamping the wire by the pulling carriage 23 deflects a second slide 38 when deflected from a release position, softer causes a jamming of the wire. The coupling of the first slider 36 with the second slider is preferably carried out by means of two matched slated planes, which allow sliding of the slides 36, 38 together and define the direction of movement of the slide.

The first slider 36 is preferably arranged in such a way on the pull slide that it is moved towards a shoulder 40 when the pull slide 23 moves from the first side to the second side. The heel 40 and the slider 36 are first brought into contact with each other as the traction carriage 23 approaches its end position on the second side. Upon further approach of the traction slide 23 to its final position on the second side of the paragraph 40 presses against the slide and displaces it from its relative position on the Zugschlitten 23 in the direction of his (in FIG. 3 shown) release position. As a result, a transfer of the wire to the second clamping device and a return of the pulling carriage 23 is made possible without wire entrainment. Fig. 4 shows the arrangement of the two gears 37, 39 relative to the Zugschlitten and the wire guide sheet 9 in a spatial representation. The first gear 37 of the twisting unit 25 is driven by means of a first gear 47. The second gear 39 of the twisting unit 25 is driven by means of a second gear 48. Gear 47 and 48 are connected by torsion shafts 55, 57 each having a servomotor. The first gear 37 and the second gear 39 are by means of the gears 47, 48 either opposite or can be driven in the same direction. By driving the gears 37, 39 in opposite directions, the respective portions of the wire through holes 43, 45 are slightly rotated relative to each other, resulting in jamming of the wire passed through the wire penetrating holes 43, 45. In the clamped state, the motors are preferably driven so that a co-driving of the gears 37, 38 takes place, such that the clamping of the wire is maintained.

Preferably, the wire feedthrough holes 43,45 are formed as elongated holes, wherein the elongated holes extend along curved paths. Preferably, the cam tracks in the first gear 37 are not congruent with the cam tracks in the second gear 47. Particularly preferably, the curved paths are formed as circular arc sections, wherein the circular arc sections associated circle centers are arranged eccentrically with respect to the respective gear. This ensures that the clamping is made particularly gentle against each other in relative movement of the gears, since the slots formed as wire guide holes only gradually from their congruent position with each of the other gear associated portion of the wire feedthrough hole are brought.

According to a preferred embodiment, the gears 37,47 each have a plurality of holes sets of wire feedthrough holes. It is expected that over time, wear will occur at the hole edges due to the clamping force application. Gears with several sets of holes then have the advantage that no complete change is necessary, but only the "advancing" the gears to the next set of holes.

Also in Fig. 4 shown is a possible embodiment of a clamping device 41 within the traction slide 23. This is in accordance with Fig. 4 performed by a rotatable pin that can taper or close the passage for the supplied wire.

With reference to the FIGS. 1 to 4 Below is a brief outline of the operation of the device 1 according to the invention. After two or more structural elements, such as tension strands, have been provided adjacent to each other, preferably crossing each other, if attachment of the two structural elements in the area of the crossing (hereinafter: twisting area) is desired, the device 1 approximated to the twist area. To encompass the twist region of the two structural elements, the second side 11 of the wire guide arc 5 is opened by actuation of the lever kinematics 15 such that the opening 7 is released. The adjacent, preferably crossing, structural elements are introduced into the inner region 27 of the wire guide arc or are guided around it like a pair of tongs.

In preparation for looping, the wire is fed in the direction of the draw slot 23 either manually or by means of a drive means such as the drive means 49. The wire is grasped by the pull slide 23 by means of a clamping device 41 and guided from the first side 9 of the wire guide bend 5 in the direction of the second side 11 of the wire guide bend. Optionally, the pull slide 23 is already partially moved along the first side 9 of the wire guide arc 5 before the wire guide arc 5 has completely settled around the structural elements and the opening 7 is closed again. When the opening 7 is closed, the pulling slide 23 is completely on the second side 11 of the wire guide bow method, where a transfer of the detected by the Zugschlitten 23 wire to the second feedthrough opening 45 of the twisting unit 25 takes place. Even before feeding the wire, it has also been passed through the first wire guide opening 43 of the twisting unit 25.

Subsequently, the wire forming a loop is clamped by means of a wire clamp 46. The pulling carriage 23 is released from the wire and moves partially or completely back to its original position on the first side of the wire guide sheet 5 (for example, according to FIG Fig. 1 ) back.

Before the twisting unit 25 carries out the twisting of the wire by rotating the two wire lead-through openings 43, 45, the length of the formed wire loop is preferably shortened to a predetermined extent, which depends on the distance between the two wire lead-through openings 43, 45 and the required minimum loop length again according to the thickness of the structural elements.

The shortening of the loop is preferably carried out by means of the drive means 49 or by re-detecting the wire by the pulling slide 23, if this is not yet completely in the position on the first side 9 of the wire guide arc 5 Fig. 1 ), and subsequent return transport by means of the pull slide.

When the loop has reached the predetermined length, the gears 37, 39 are first driven in opposite directions by means of the gears 47, 48 and the motors connected to them, until a sufficient clamping within the twisting unit 25 is obtained. In this locked state, the gears 37, 39 are then driven in the same direction, and the wire is preferably separated within the device 1 by means of a cutting body, for example by means of one or more cutting edges on the gears. the twisting unit 25 performs a twisting movement about the axis X following the separation. After the desired number of revolutions, the opening 7 is released again and the device 1 is removed from the twisting area, for example to perform a next twisting operation.

As can be seen from the above descriptions, the whole process of looping and twisting is automated, which is a significant labor hassle for operators.

Claims (17)

1. An apparatus (1) for automatically twisting metal wires, in particular for connecting adjacent, preferably mutually crossing structural elements, comprising

   a wire feed means for feeding wire, preferably endless wire, into the apparatus,

   an arcuate wire guide (5) which has a selectively openable and closable opening (7) and which is adapted to guide the fed wire in the closed position along the arcuate wire guide from a first side (9) of the arcuate wire guide to a second side (11) of the arcuate wire guide, that is in opposite relationship with respect to the opening, and

   a twisting unit (25) adapted to engage the fed wire on both sides of the arcuate wire guide and to twist it by means of a rotational movement
   characterized by a pulling slider (23) adapted to engage the fed wire on the first side (9) of the arcuate wire guide and to pull it, when the arcuate wire guide is closed, towards the second side of the arcuate wire guide along the arcuate wire guide.
2. An apparatus according to claim 1 wherein the arcuate wire guide (5) is of a tongs-like configuration and the selectively openable and closable opening (7) is arranged proximally on the apparatus (1).
3. An apparatus according to claim 1 or claim 2 wherein the twisting unit (25) has a first wire guide passage hole (43) and a second wire guide passage hole (45) and wherein the wire feed means is adapted to pass the fed wire through the first wire guide passage hole.
4. An apparatus according to claim 3 wherein the pulling slider (23) is adapted to pass the wire pulled to the second side (11) of the arcuate wire guide through the second wire guide passage hole (45) in such a way that the wire forms a loop from the first to the second wire guide passage hole.
5. An apparatus according to claim 3 or claim 4 comprising a clamping device (41, 46) which is preferably arranged on the first or the second side of the arcuate wire guide and which is adapted to hold fast the wire passed through the first wire guide passage hole or is adapted to hold fast the wire passed through the second wire guide passage hole.
6. An apparatus according to claim 5 comprising a drive means (31, 49) for wire conveyance, wherein the drive means is adapted to convey the wire passed through the second wire guide passage hole (45) and held fast by the clamping device (46) to shorten the formed loop to a predetermined size.
7. An apparatus according to claim 6 wherein the drive means (49) is associated with the wire feed means and is adapted to convey the wire selectively in the feed direction or in opposite relationship to the feed direction.
8. An apparatus according to claim 6 wherein the drive means (33) has a drive member which is motor-drivable and is coupled to the pulling slider in such a way that the pulling slider is displaceable selectively from the first side of the arcuate wire guide towards the second side of the arcuate wire guide and from the second side of the arcuate wire guide towards the first side of the arcuate wire guide.
9. An apparatus according to one of claims 3 to 8 wherein the twisting unit has two coaxially arranged gears (37, 39) through which the first and second wire guide passage holes respectively completely extend and wherein the two gears are drivable both in opposite directions and also in the same direction.
10. An apparatus according to one of the preceding claims comprising a cutting body which is arranged to sever the wire within the apparatus and is adapted to sever the wire on the first side of the arcuate wire guide and/or on the second side of the arcuate wire guide.
11. A method of automatically twisting a metal wire for connecting two or more adjacent, preferably mutually crossing structural elements, comprising the steps:

    - providing two adjacent, preferably mutually crossing structural elements,

    - feeding the wire into an apparatus according to one of claims 1 to 10,

    - passing a crossing region of the structural elements through the opened opening of the arcuate wire guide of the apparatus,

    - closing the opening of the arcuate wire guide so that the crossing region of the structural elements is enclosed by the arcuate wire guide,

    - engaging the fed wire by means of the pulling slider,

    - pulling the fed wire by means of the pulling slider, with the arcuate wire guide closed, along the arcuate wire guide from the first side of the arcuate wire guide to the second side of the arcuate wire guide, that is in opposite relationship with respect to the opening,

    - engaging the fed wire on both sides of the arcuate wire guide by means of the twisting unit, and

    - twisting the engaged wire by means of a rotational movement of the twisting unit.
12. A method according to claim 11 wherein the step of engaging the fed wire by means of the twisting unit includes one or both of the steps:

    - passing the fed wire through a first wire guide passage hole of the twisting unit, preferably by means of the wire feed means of the apparatus, and

    - passing the wire which has been pulled to the second side of the arcuate wire guide trough a second wire guide passage hole of the twisting unit in such a way that the wire forms a loop from the first to the second wire guide passage hole around the structural elements.
13. A method according to claim 12 including:

    - holding fast the wire passed through the first wire guide passage hole or the wire passed through the second wire guide passage hole by means of a clamping device of the apparatus.
14. A method according to claim 13 including:

    - conveying the wire passed through the second wire guide passage hole and held fast by the clamping device in such a way that the formed loop is reduced to a predetermined size.
15. A method according to one of claims 11 to 14 wherein the step of engaging the fed wire on both sides of the arcuate wire guide by means of the twisting unit includes:

    - driving in opposite directions two coaxially arranged gears, through which the first and second wire guide passage holes respectively completely extend, in such a way that the wire passed therethrough is clamped, and

    wherein the step of twisting the engaged wire by means of rotational movement of the twisting unit includes:

    - driving in the same direction the two gears with the clamped wire.
16. A method according to one of claims 11 to 15 including the step:

    - severing the wire on the first and/or on the second side of the arcuate wire guide by means of a cutting body within the apparatus prior to the twisting step.
17. Use of an apparatus (1) for automatically twisting metal wires, in particular for connecting adjacent, preferably mutually crossing structural elements, for the production of a reinforcing cage for a pylon element of a wind power installation, wherein the apparatus is designed in accordance of one of claims 1 to 10, wherein
    the reinforcing cage as first structural elements has a plurality of first and second prestressing cables arranged in mutually crossing relationship.

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