EP0371960A2 - Method for bending bar-shaped materials - Google Patents

Abstract

The machine is capable of bending reinforcing steel rod (142) accurately in either direction by using just two bending slides (144) and (146). The two bending slides hold the material (142) in alternating sequence i.e. when one slide holds the material, the other carries out the bending. The holding of the material in a particular section is effected by bending crank (152) swinging around bending mandrel (154) and bending the rod by a specified angle alpha which, for the material in question is within the elasticity limit of the rod. Actual bending takes place, but the elastically deformed section of the rod produces the clamping effect between the bending roll and mandrel.

Description

The invention relates to a method and an apparatus for bending rod-shaped materials such as reinforcing steels comprising bending slides, each with a bending mandrel and a bending crank arranged rotatably around the latter, the rod-shaped material being gripped and bent by the bending slides in such a way that a section of the material alternately is immovably fixed by one of the bending slides, during which the bending sled not holding the material bends the material or is displaced along it.

EP-A-0 121 896 describes a device for bending rod-shaped materials, which comprises two bending slides, each with a mandrel with an associated bending crank. A section of material is held by a bending slide during the bending process. The other bending slide is used to bend. So that the material is not displaced during bending, so that the non-bending bending slide firmly holds the material, it is necessary that the material is already plastically deformed in this section.

The object of the present invention is to develop a method of the type described in the introduction in such a way that a bending process is possible in which any desired bending shapes are possible with high accuracy, with other bending slides in addition to the bending slides facilities holding the material are not required. Furthermore, the invention is based on the object of developing a device in such a way that the movement of the bent material section is not impeded by the bending slide. Finally, the possibility of a problem-free material supply and dispensing should be possible.

The object is achieved on the one hand in that, for the immovable fixing of the material, a section which interacts with a bending slide and is not bent is bent by an angle which leads exclusively to an elastic deformation. In other words, it is proposed according to the invention that the bending slide can also hold rod material when it is still undeformed. This is not possible according to the state of the art. This has the particular advantage of using materials to e.g. To form Z-shapes or modifications of these.

According to the invention, the elastic deformability of the material is taken into account. Accordingly, if the material is bent by an angle that does not yet lead to permanent deformation, it is ensured that the material is held securely by the bending slide, so that the other bending slide can be displaced to the required extent and, if necessary, can carry out the plastic deformation. In particular, the angle, which can also be referred to as the spring-back angle, is added to each nominal angle, that is to say the angle to be bent, in order to ensure that the plastically deformed section also has the desired geometry when the bending carriage no longer acts. Accordingly, the angle should be the angle by which the material is maximally bendable without plastic deformation. The angle is therefore also the spring-back angle.

A further embodiment of the invention is characterized in that when a closed bending mold is bent in, the material present in the region of a bending mandrel is bent over the bending mandrel via material to be bent, for example via a transfer plate. As a result, the further bending process is not hindered.
Further details, advantages and features emerge both from the claims, the features to be extracted from them - individually and / or in combination -, the following description and exemplary embodiments shown in the drawing, the drawing without any further explanations being required. essential features of the teaching according to the invention can be seen, even if they are not described in more detail.

• Fig. 1 eine erfindungsgemäße Vorrichtung in Draufsicht,
• Fig. 2 a-c Hydraulikschaltpläne,
• Fig. 3 einen Einsatz der Vorrichtung nach Fig. 1 in einer Arbeitsstraße,
• Fig. 4 eine Detaildarstellung eines Antriebs einer Biegekurbel,
• Fig. 5 einen Ausschnitt einer ersten Ausführungsform eines Biegeschlittens,
• Fig. 6 bis 8 schematische Darstellungen von Biegevorgängen,
• Fig. 9 ein im Bereich eines Biegedorns angeordneten Überleit­blechs und
• Fig. 10 und 11 Biegeformen von Rundstahl, die mit der erfindungsgemäßen Vorrichtung hergestellt werden können.

Show it:

• 1 shows a device according to the invention in plan view,
• 2 ac hydraulic circuit diagrams,
• 3 shows an application of the device according to FIG. 1 in a work street,
• 4 shows a detailed illustration of a drive of a bending crank,
• 5 shows a detail of a first embodiment of a bending slide,
• 6 to 8 are schematic representations of bending processes,
• 9 shows a transfer plate arranged in the region of a bending mandrel and
• 10 and 11 bending shapes of round steel, which can be produced with the device according to the invention.

In Fig. 1, a bending machine (10) is schematically shown in plan view, which comprises a horizontally lying processing table. In the exemplary embodiment, two bending slides (14) and (16) are displaceably arranged in the longitudinal direction of the processing table, by means of which the preferably rod-shaped steel materials (18) to be introduced into the bending machine (10) are to be bent, as described in more detail below. These bars (18) enter the machine from a material store (20), it being possible for a plurality of bars (18) to be bent simultaneously by means of the bending slides (14) and (16). The material store (20) can be part of a processing line shown schematically in FIG. 3, which is arranged between the bending machine (10) and a bar cutting machine (22). The rod cutting machine can obey a principle as described in German patent application 32 06 673 by the same applicant. The material store (20), which can be a bending carriage runway, also serves as a buffer. The use of the machine (10) in a processing line has the advantage that there is a high throughput without the need for further explanations. The bending machine (10) can be programmed via a keyboard (24) in order to cold-deform the materials (18) to the desired extent. It should also be mentioned that the work surface (12) has a vertical or almost vertical slot for receiving several round materials to be arranged one above the other, which is laterally delimited by the bending slides (14) and (16). In addition to the machine (10), a container (26) is also indicated, into which the bent materials (29) are thrown by hand can. Of course, there is also the possibility that an automatic ejection device is integrated in the machine (10).

Finally, counterholders (136) are drawn in in FIG. 1, which prevent bending when the material (18) is bent.

Each bending slide (14) or (16) consists of a bending crank (28), a bending mandrel (30) and a drive (32), (34), (36) or (38). The bending crank (28) moves at a distance around the bending mandrel (30). The materials to be deformed are then located between the bending crank (28) and the bending mandrel (30). As indicated in Fig. 5, the bending crank (28) comprises an eccentrically mounted roller mandrel (40), which may be rotatable about its axis, and which is in the desired position via two opposing threads (42) and (44) (infinitely adjustable axis distance bending roller (40), Bending mandrel (30)) is fixed immovably, so that the bending mandrel (40) cannot be released regardless of the direction of rotation of the bending crank (28). The bending crank (28) is also received eccentrically by a shaft (46) which is connected to one of the hydraulic cylinders (36) or (38). The longitudinal movement of the hydraulic cylinder (36) or (38) is converted into the desired rotary movement via a chain (48). The chain (48) interacting with the shaft (46) is connected at one end to the hydraulic cylinder (36) or (38) and at the other end via a spring-loaded element (50). The exact structure and the mode of operation can easily be seen from FIG. 4.

If the rotary movement of the bending crank (28) is preferably brought about by means of hydraulic cylinders (36) and (38), the translational movement of the bending slide (14) or (16) itself preferably takes place via hydraulic motors (32) and (34) with a rotary output movement. Both the hydraulic cylinders (36) and (38) and the hydraulic motors (32) and (34) can be located in a hydraulic circuit (52), one motor M two pumps (56) actuated, which are connected in parallel. If the elements (36), (38), (32) and (34) are arranged in a single circuit (52), there is the advantage that all drive means can be operated with a single unit, so that complex monitoring and Control devices are not required. But even if only a single hydraulic circuit is required, it is nevertheless ensured that all drive means (32) to (38) can be operated completely independently of one another. According to the invention, the individual drive means (32), (34), (36), (38) in the circuit (52) are now arranged as follows. The first hydraulic motor (32) is located behind the pump (56) conveying the operating medium (54). The second hydraulic motor (34) is arranged in the circuit behind the first hydraulic motor (32). Then the hydraulic cylinders (38) and (36) follow to close the circuit. In the exemplary embodiment, the connection between the circuit (52) and the drive elements (32) to (38) is established via solenoid valves (58), (60), (62) and (64). If all valves (58) to (64) are closed, the equipment (54) runs freely in the circuit (52). Now z. B. the valve (60) activated in such a way that a connection to the hydraulic motor (32) is carried out - consequently a connection PB / AT or PA / BT is established - so can otherwise not activated valves (62), (64) and (58) the equipment continues to flow back immediately without pressure. However, if the valve (62) is also actuated, i.e. if both bending slides (14) and (16) are to be displaced at the same time, the hydraulic motor (34) is acted upon by the return fluid of the motor (32) without the independence of the actuation being canceled thereby becomes. Accordingly, the return fluid of the engine (34) can act on the hydraulic cylinders (38/36). The same can of course also take place if only one of the hydraulic motors (32) or (34) or none of these is acted upon by the operating means (54). From the description given above it follows that the drive means (32) to (38) for actuating the bending slide (14) and (16) are arranged in a single hydraulic circuit (52) and can be activated completely independently of one another, but also together.

The advantage of the tandem pump arrangement according to FIG. 2a is that, with different delivery volumes of the pumps (56), a change in speed can easily be achieved by optionally switching one of the pumps on and off. According to FIG. 2b, the individual pumps (56) with the elements (36) and (38) or (32) and (34) and according to FIG. 2c with the elements (32) and (36) or (34) and (38) arranged in a circuit. Nevertheless, despite the division of the hydraulic circuits, it can be said that all elements are actuated by a single unit, namely the motor M and the pumps (56).

An essential feature of the invention is that during the bending process, a section of the material is held between the mandrel and the bending crank in such a way that when the other bending slide is moved along the material, it cannot move. A corresponding bending process will now be explained in more detail with reference to FIGS. 6 to 8. The individual parts of the bending slide shown are not described in detail. Rather, the bending slide can have a structure as described in more detail in connection with FIGS. 4, 5.

6 and 7, a rod-shaped material such as reinforcing steel (142) is to be bent on both sides with respect to its longitudinal axis. For this purpose, two bending slides (144) and (146) are used, which alternately hold the material (142) precisely in position and bend to the desired extent. First, the bending slide (144) holds the material (142) in position A. Since the material is not yet to be bent, it is first bent at an angle. The angle depends on the rod material. The angle is like this great that the material is only elastically and not plastically deformed. However, since the material is bent by the angle - there is a clamping between the bending mandrel (148) and the bending crank (150), namely in the broken line of position A. The bending slide (146), which can also be referred to as a bending stick , is in position Z. If the end of the material (142) is now to be bent by the angle -, the bending crank (152) is rotated around the bending mandrel (154) of the bending block (146) by the angle +, the The angle corresponds to the angle by which the material springs back when the bending crank (152) no longer acts on the material (142) in the region of the end. If the first bending process (position Z) has previously been described in such a way that the material (142) has bent by the angle during the bending of the bending carriage (144), the elastic deformation can of course be canceled by the bending carriage (146) after the beginning of the bending process are, ie the bending crank (150) returns to the basic position (solid line). It is important, however, that at least when moving one of the bending slides, the other clamps the material.

In order to bend the left end of the material (142) again in a position Y to the desired extent, the material (142) is clamped again by the bending stick (144) (that is to say bending by the angle). As soon as the position Y is reached, the bending stick (144) can open again to release the clamping. The bending stick (146) then bends the material (142) again in the Y position. The bending stick (144) should only finally release the clamping when the bending stick (146) has already initiated the bending process to ensure that the material (142) cannot be moved along its longitudinal axis during the bending. In order to initiate a further bending process, in such a way that the end gripped by the bending slide (144) is bent in the opposite direction than the opposite end, the bending slide (146) in the position X shifted. Here, the bending carriage (144) clamps the material (142) again. The rod (142) is then turned through 180 °. The bending slides (146) and (144) must release the material. Now the bending slide (144) should bend the associated end. As a result, the bending stick (146) is clamped by elastic deformation of the material (142) (bending by the angle), in order then to rotate the bending crank (150) around the bending mandrel (148) to the desired extent. The angle of rotation is equal to the desired angle, which corresponds to the angle at which there is only an elastic but no plastic deformation of the material. As soon as the bending process in position A is complete, the bending slide (146) clamps the material (142) in position X. Then the bending slide (144) is moved to position B. As soon as the bending process begins in position B, the bending slide (146) can release the clamping.

6 and 7 has therefore made it clear that, without the material having to be deformed, each bending slide (144) or (146) can clamp the rod material (142) by utilizing the elastic property of the material. The clamping takes place at least when one of the bending slides (144) or (146) moves along the material (142).

A further bending process can be seen from FIG. 8, which is carried out via bending slides or bending sticks (156) and (158). Here, too, at least when a bending slide (156) or (158) is moved, the other bending slide (158) or (156) is in a clamping position. The material (160) to be deformed is bent between the bending slides (156) and (158) (dashed line). This shows that, in order to rule out any distortion of the length, the clamping is only to be carried out during the process, whereas the clamping position is canceled during the bending, so that the slide carrying out the bending process the Material can bend at the point corresponding to the actual length. Otherwise it would be necessary to arrange counterholders along the length of the material (160), but this would prevent free movement of the bending slides (156) and (158). 8, the bending process takes place as follows. The rod material (160) is first plastically deformed in position C of the bending slide (156) and in position W of the bending slide (158). The bending carriage (158) then clamps the rod material (160) so that the bending carriage (156) can move into position D. The material (160) is bent during the process. During the bending process in position D, however, the clamping action of the bending slide (158) is released, so that the material (160) assumes the position that is indicated by the solid line. After bending in position D, the material (160) is clamped again by the bending slide (158). The bending slide (156) is then moved to position E. A bending process also takes place in this position. Finally, the carriage (156) is moved to position F with material (160) clamped by the bending carriage (158) to allow the final bending operation. All bending processes take place at an actual angle = target angle (the angle by which the end material should be bent) minus the angle (the angle at which the material is not yet plastically deformable). (The angle can be programmed into a bending machine, depending on the materials to be bent and their dimensions.

The filled or open rectangles drawn in the bending slide (156) and (158) above the material (160) represent the counterholders (136) shown in FIG. 1, which are intended to prevent the material (160) from bending during bending. These counterholders are attached to the bending slide so that they cannot represent any hindrance when they are moved.





Any bends can be made, the material itself can optionally be rotated about its longitudinal axis. This ensures that when moving a bending slide, the material itself is held firmly and can still be rotated as desired after the process.

It is illustrated with reference to FIG. 6 that the rod material (142) can no longer be displaced in length in its elastic deformation due to the interaction between the bending roller (150) and the bending mandrel (148). As soon as the rod material (142) has been bent by the angle, the counterforces caused by the bending roller (150) and the bending mandrel (148) together with the coefficient of friction of the rod material (142) are sufficient to prevent the material from being displaceable in length; Otherwise, the force acting in the longitudinal direction would not only have to overcome the forces and frictional forces caused by the above-mentioned elements, but also continuously bend the material so that it can slide out of the area between the bending crank (150) and bending mandrel (148), in both Directions. The angle (clamping angle) is selected such that the material is only elastically and not plastically deformed, ie that when the bending crank (150) is moved back, the material is moved back to its starting position.

It should also be mentioned again that the rectangles shown in the figures in the area of the bending slide (146) or (144) above the material (142) are completely filled (in the area of the bending slide (144), in the area of the two right-hand bending slides (146 ) not filled) serve as counter bearings, which ensure that when the material is bent, the rod (142) cannot be bent between the bending slides.

10 and 11 show various bending shapes of round steel, which can be achieved using the teaching according to the invention. A great variety can be seen, although it should be noted that the accuracy of the end products is very high, so that the ejection of the cold-formed materials which are not to be used is extremely low.

Claims (8)

1. A method for bending rod-shaped materials such as reinforcing steels comprising bending carriages each with a bending mandrel and a bending crank arranged rotatably around the latter, the rod-shaped material being gripped and bent by the bending carriages in such a way that a section of the material is alternately immovably fixed by one of the bending carriages , during which the bending carriage, which is not holding the material, bends the material or is moved along it,
characterized by
that for the immovable fixing of the material, a section which interacts with a bending slide and is not bent is bent at an angle which leads exclusively to an elastic deformation. 2. The method according to claim 1,
characterized by
that the angle is added to the desired bending angle determining the final shape of the material with each bending operation. 3. The method according to claim 1,
characterized by
that the angle is the angle through which the material is maximally bendable without plastic deformation taking place. 4. The method according to claim 1,
characterized by
that the bending by the angle is released during the bending of the material with the other bending slide. 5. The method according to claim 2,
characterized by
that the bending carriage holding the material is turned back by the angle to the bending angle along the material during the movement of the other bending carriage. 6. The method according to claim 1,
characterized by
that in the area of a bending slide, curved material sections are raised above material sections to be bent. 7. The device comprising a bending slide with a bending mandrel and a bending crank which is rotatably arranged around it for clamping or bending rod-shaped materials such as reinforcing steels according to claim 1,
characterized by
that the bending slide (158) is assigned a transfer plate (166) through which bent material (164) can be guided over the bending mandrel (168) of the bending slide. 8. The device according to claim 7,
characterized by
that the transfer plate (166) acts as a ramp with respect to the material (164), and that preferably the transfer plate (166) can be rotated about a point (170) remote from the bending mandrel.

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