METHOD FOR BENDING BENDABLE ELONGATE METAL PROFILES, ESPECIALLY STEEL RODS FOR CONCRETE ENFORCEMENT, BY A MOVABLE BENDING UNIT AND MACHINE THEREFORE

Abstract

 A machine (1) and method for bending a long bendable elongate metal profile (2), for example a steel rod, particularly a concrete reinforcing steel rod. The machine (1) comprising a frame (3) and a bending unit (4) mounted on the frame (3) for bending the metal profile while it is guided through the bending unit (4). The frame (3) is provided movable on a support (9). When the metal profile (2) is inserted into the bending unit (4), and the metal profile (2) is fixed with respect to its longitudinal direction, the roller bending causes a dragging of the frame (3) along the metal profile (2) through pulling or pushing force exerted on the metal profile (2) by the bending unit (4).

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a method for bending bendable elongate metal profiles with a machine for bending bendable elongate metal profiles, especially steel rods for concrete enforcement. The invention also comprises a use of such a machine.

BACKGROUND OF THE INVENTION

[0002] Machines for bending that are used for concrete enforcement are disclosed in European patent applications EP0715907, EP0900602, and EP1494825. Such machines comprise a stationary bending mechanism supported on a frame. Although such machines are useful for bending in factories, problems arise when the metal profiles are very long because the profiles are difficult, if not impossible, to transport after bending. The stationary machines imply some tight constraints on the maximum size for such metal profiles. In case of the desire to bend large metal profiles, it is necessary to perform at least part of the bending on site, for example at the construction site of a bridge, a tunnel, or a wind turbine. However, even with a stationary bending machine on site, there is a disadvantageous requirement of space, because a long metal profile, for example with a length of 20 meters, would have to be guided manually into the machine and received manually on the opposite side of the machine during the bending phase, which is demanding manpower and is heavy manual work.

[0003] European patent application EP0416223 discloses a bending machine with a bending wagon that is moving along a metal profile which has one end fixed in a frame such that the metal profile is bent along its length due to the motion of the bending wagon. The bending wagon is pulled by a chain and guided on rails along the frame. EP1468756 discloses a bending machine with two movable bending heads provided on carriages on a frame. The carriages are moved by actuators, for example screw-nut or pinion-rack connections. The rotation of the bending means and the movement of the bending heads along the base are combined by electronic control. Although, these systems imply improvements in the art, the transport of the bending head and the speed of rotation of the bending means imply a requirements of careful adjustment of relative speeds and therefore makes the system relatively complicated.

[0004] Therefore, it would be desirable to find a better solution for concrete enforcement by metal profiles. Thus, there is a general need for improvements in the art.

DESCRIPTION / SUMMARY OF THE INVENTION

[0005] It is the objective of the invention to provide an improvement in the art. Especially, it is an objective to provide an improved method and machine suitable for bending long metal profiles, for example metal profiles having a length of more than 10 meters, more than 15 meters or even more than 20 meters. It is another objective to provide an embodiment of the machine that is easy to produce, easy to transport and flexible in use.

[0006] This objective is achieved with a method for bending elongate profiles, for example steel rods, particularly concrete reinforcing steel rods, and an apparatus as described in the following.

[0007] The term elongate is used, as the metal profile is more than 10 times, typically more than 100 times, longer than wide. The term "longitudinally fixed" means that the profile is prevented from movement in the longitudinal direction of the metal profile, seeing that the metal profile is elongate, and, therefore, has a longitudinal direction and a transverse direction.

[0008] The machine comprises a frame on which a bending unit for roll bending is mounted. The bending unit comprises a number of rollers for positioning the metal profile between the rollers such that pressure is exerted on the metal profile by the rollers at different locations on opposite sides of the metal profile. By displacing the rollers relatively to each other, variable pressure is exerted on the metal profile such that it is bent into a desired curved metal profile. The bending unit causes bending of the metal profile while the metal is guided through the rollers of the bending unit. The guidance is caused by a pulling or pushing force exerted on the metal profile along the longitudinal direction of the profile by the machine during the operation of the machine for bending the profile.

[0009] This is an advantage relatively to the bending machines according to the prior art in that a precise synchronization of the movement of the bending unit along the profile and the rotation of the bending rollers is not necessary. The dragging of the bending unit on the metal profile automatically and inherently adjusts the speed along the profile and the rotation of the bending rollers.

[0010] The frame is provided movable on a support. The metal profile is positioned in the bending between the rollers with a first section of the metal profile on one side of the bending unit and a second section of the metal profile on the opposite side of the bending unit. While the metal profile is longitudinally fixed against longitudinal movement, the frame with the bending unit is moved on the support along the metal profile towards the first or second section, depending on the conditions, thereby causing bending of the metal profile. For example the machine is dragged along the metal profile due to the driven rotation of the rollers in the bending unit which exerts a pushing or pulling force on the metal profile. Although, additional forces can be acting on the profile in the longitudinal direction, preferably, the dragging by the rollers is the only force, or the substantial force along the longitudinal direction, that is causing the bending unit to move along the profile.

[0011] Typically, the metal profile is fixed at one or two fixtures remote from the bending unit, and the frame with the bending unit is driven towards such fixture.

[0012] For example, the bending unit comprises a rotational bending disc and two rotational bending rollers arranged in triangular configuration for taking up the metal profile between the bending disc and the two bending rollers such that the bending disc is on one side of the metal profile and the two bending rollers on the opposite side of the metal profile. The bending disc and the two bending rollers are configured for mutually relative movement; that is, the bending disc is movable and the bending rollers are stationary, or one or two of the bending rollers are movable and the bending disc is stationary, or the bending disc as well as one or two of the bending rollers are movable. For example, one or two of the bending rollers are different from the bending disc in size by having a smaller diameter.

[0013] For example each of the bending disc and the bending rollers is arranged rotational about a vertical axis, and the metal profile is bent in a horizontal plane or substantially horizontal plane.

[0014] Although, the orientation of the machine can be varied, for example during transport for delivery, or during repair, where is may even be oriented upside down, it is reasonable to denote one side as the underside and one side as the top side, because there is a natural orientation of the machine for proper functioning. Likewise, also the terms horizontal and vertical makes sense not only with respect to executing the method but also for the machine.

[0015] In some embodiments, the relative movement of the bending disc with respect to the bending rollers is in a direction towards a straight line connecting the two bending rollers in order to exert pressure by the bending disc on the metal profile while it is abutting the bending rollers on the opposite side of the metal profile. For example, the relative movement of the bending disc with respect to the bending rollers is in a direction normal to a straight line connecting the two bending rollers, although, this is not necessary and depends on the situation and configuration.

[0016] In operation, the metal profile is placed on the frame in tangential abutment to the bending disc and the two bending rollers and the bending disc is relatively displaced towards the straight line for thereby exerting pressure laterally onto the metal profile and pressing the metal profile into a bent towards a smaller bending radius. By rotating the bending disc, the bending unit on the frame is driving, such as dragged, along the metal profile while exerting bending pressure on the metal profile by the bending disc and the bending rollers.

[0017] In some embodiments, the frame is provided rolling or sliding on rails. In this case, a section, for example an end, of the metal profile is fixed for preventing longitudinal movement of the metal profile; the metal profile is positioned in the bending unit between the rollers, and the frame is moved with the bending unit along the profile towards the fixed section, by which operation the metal profile is bent by the bending unit. Typically, although not strictly necessary, the rails are straight for a linear motion of the frame along the rails. Advantageously, the metal profile comprises a free section that is on an opposite of the bending unit relatively to the fixed section, wherein that free section is arranged for freely bending away from the bending unit during the bending operation of the bending unit while moved by the frame on rails.

[0018] In other embodiment, the frame is provided with at least three wheels, for example four wheels, for rolling on a support, for example flat ground support. Each of the wheels is mounted on a castor-swivel axis on an underside of the frame for free rolling and unhindered change of rolling direction of the machine on the support. Thus, all the wheels on the machine by which it is configured for rolling on a support comprise a castor-swivel axis. The wheels are spanning a plane that coincides with the support, for example flat ground support, when the machine is placed on such support. The machine is configured roll on the support while being dragged along the metal profile during bending of the metal profile when the metal profile is fixed with respect to its longitudinal direction.

[0019] For example, the frame is moved with wheels rolling on a flat, horizontal or substantially horizontal ground surface. Thus, this embodiment of the machine with the swivelling wheels is not intended to be mounted with the wheels rolling on a vertical wall; also, the wheels are not fastened to a rail that would prevent a lifting off the ground of the machine. Such rail mounting would be necessary when rolling on a vertical wall but would impede free rolling and would hinder a free change of rolling direction. Thus, instead, for this embodiment, the wheels are freely rolling on the ground only by the weight of the machine and can be lifted off the ground when lifting the weight of the machine.

[0020] Optionally, the metal profile may be guided through the bending unit a number of times back and forth in order to gradually decrease the bending radius of the metal profile.

[0021] For example, the bending unit is provided on a top side of the frame, the top side being opposite to the underside. Optionally, the bending disc is arranged rotational about an axis that is normal to the plane and, thus, normal to the flat ground support when the machine is placed on such flat ground support.

[0022] In some operational embodiment, the first section of the metal profile, for example the first end of the metal profile, is fixed in a first fixture that is stationary in position and turnable for following an induced bend in the profile. The second section, for example the second end, of the metal profile is fixed in a second fixture which is turnable and, in addition, translational in order to compensate for a changing distance between the two fixtures and when the metal profile is bent. Bending of the metal profile is done while the frame with the bending unit is moving towards the first or second fixture, typically towards the second fixture. It is implicitly understood that the first and the second fixture are remote from the bending unit.

[0023] For example, in some embodiments, the machine is be provided as an apparatus comprising the bending unit, where the apparatus is mounted onto a cart, also called trolley. This is an easy and low cost production principle, as carts with castor-swivelling wheels are standard products, available off shelve in various sizes.

[0024] Advantageously, in such case, the frame comprises a handle for manual movement by push or pull of the machine on the flat ground support, the handle being provided at a distance of between 0.6 m and 1.6 m from the plane. In case that the frame is positioned at a distance from the metal profile, for example at a distance that is at least an order of magnitude larger than the largest of width or length of the machine; the machine can be moved to the metal profile by manually pushing or pulling the machine by the handle and thereby causing rolling of the machine on the flat ground support towards the metal profile. A typical dimension of the machine and the frame is between 0.5 and 2 meter in width and between 0.8 m and 3 m in length.

[0025] It is within the scope of the invention that more than one bending unit is used for bending a single metal profile. For example, two or more bending units on two or more movable frames are provided in the machine. For example, two bending units move in opposite directions in order to increase the bending speed.

[0026] Such a machine and method are especially useful for bending a concrete-reinforcing steel rod prior to moulding the bent steel rod into the concrete construction

SHORT DESCRIPTION OF THE DRAWINGS

[0027] The invention will be explained in more detail with reference to the drawing, where

FIG. 1

is a sketch of one embodiment of the apparatus, in a) top view and b) side view;

FIG. 2

is a sketch of a possible use of the machine in a) start position and b) after bending;

FIG. 3

is a drawing of a second embodiment, where the frame with the bending unit is rolling on straight rails, in a) top view and b) side view.

DETAILED DESCRIPTION / PREFERRED EMBODIMENT

[0028] FIG. 1 illustrates a machine 1 for bending a bendable elongate metal profile 2, for example a steel rod, particularly a concrete reinforcing steel rod. The machine 1 comprises a frame 3 upon which a bending unit 4 is mounted.

[0029] The bending unit 4 comprises a rotational bending disc 5 and two rotational bending rollers 6 with their centres arranged in triangular configuration for taking up the metal profile 2 between the bending disc 5 and the two bending rollers 6 such that the bending disc 5 is on one side of the metal profile 2 and the two bending rollers 6 on the opposite side of the metal profile 2.

[0030] Further, a guiding disc 15 is, optionally, used for pressing the metal profile 2 against the bending disc 5. As illustrated, the metal profile 2 is provided between the bending disc 5 and the guiding disc 15, such that the bending disc 5 is on one side of the metal profile 2 and the guiding disc 15 and the bending rollers 6 on the opposite side. The guiding disc 15 is optional and can be avoided; on the shown embodiment, the centre of the guiding disc 15 and the centre of the bending disc are on a line 16 perpendicular to the straight line 11 that connects the centres of the bending rollers 6. However, this configuration is not necessary can deviate therefrom dependent on the use of the machine 1. In the situation as illustrated, the linear transverse movement of the bending disc 5 and/or the guiding disc 15 is centrally between the two bending rollers 6, although in other embodiments, the movement need not be centrally in this way. This line 16 is also the direction for the relative movement 19 of the bending disc 5 with respect to the bending rollers 6. The term "relative movement" is used here because the pressure of the disc 5, 15 and rollers 6 against the metal profile 2 for the bending can be accomplished by moving the bending disc 5 or the bending rollers 6 or both in the direction as indicated by arrows 17, 18 and 19. Depending on whether the bending disc 5 can be moved and/or the bending rollers 6, the translational movement 20 of the guiding disc 15 is also optional. Due to the optional movements of the bending disc 5 or the bending rollers 6, and the resulting optional movement of the guiding disc 15, the movements are illustrated by dashed arrows 17-20 in the figure and not solid arrows. Thus, the machine 1 may function without movement 17-20 of all four discs and rollers; for example, the bending disc 5 may be stationary. However, it is advantageous to have the possibility to adjust both discs 5, 15 and rollers 6. The rotation of the discs 5, 15 and rollers 6 as compared to the approximate moving direction 23 of the frame 3 is indicated by bent arrows.

[0031] The bending rollers 6 are provided on rails 22 for continuous displacement, for example by an actuator, along the rail 22. This situation would allow the bending disc 5 to be stationary. Alternatively, the rollers 6 may be manually mounted in a set of a plurality of equidistant holes provided in the rails 22; the latter situation would require a movable bending disc 5 in order to adjust the bending radius continuously.

[0032] The bending disc 5 comprises an upper disc part 5' and a lower disc part 5" with a larger diameter in order for the metal profile 2 to rest on the lower disc part 5" when abutting the upper disc part 5' tangentially.

[0033] In contrast to stationary machines, the machine 1 as illustrated comprises at least three wheels 8 under the frame 3 for rolling of the frame 3 on a ground support 9, such as a floor in a building. Each of the wheels 8 is mounted on a castor-swivel axis 10 on the underside of the frame 3 for free rolling and unhindered change of rolling direction of the frame 3 on the flat ground support 9. Such wheels 8 are known from typical trolleys or carts. The castor-swivel mounting 10 of all wheels 8 allows an easy change of direction of the frame 3. Typically, there is mounted one of such wheels 8 in each corner of the frame 3, although 3 wheels would be sufficient in principle.

[0034] The bending disc 5 is mounted on a rotational axis 14 which is driven by a motor 21, typically electrical motor, such that the metal profile 2 is pulled by the periphery of the bending disc 5, potentially assisted by the guiding disc 15, between which the metal profile 2 is provided. The guiding disc 15 can be a free running disc or potentially also being driven by a motor in order to assist and smooth the transport of the metal profile 2 in the gap between the bending disc 5 and the guiding disc 15, both of which are abutting the metal profile 2. The bending rollers 6 are potentially provided free running, such that the bending disc 5, optionally in cooperation with the guiding disc 15, is the element that is driving frame 3 along the metal profile 2. Optionally, also the bending rollers 6 are motor driven for transport of the frame 3 along the metal profile 2. Alternatively, the bending rollers 6 are driven by the motor and the bending disc 5 is not driven but a passively rolling element.

[0035] In contrast to stationary machines, where the metal profile 2 is moving and the machine is stationary, the frame 3 of the bending machine 1 as illustrated in FIG. 1 is a fully mobile vehicle with swivelling wheels 8, such that the metal profile 2 can be fixed with respect to its longitudinal direction, for example fixed in one or two sections, such as one or two ends or, and the frame 3 with the bending unit 4 is caused to move along the metal profile 2 instead of the metal profile 2 moving through the bending unit 4. The rotation of the bending disc 5 causes the frame 3 to be dragged along the metal profile 2 which is brought into an increasingly bent state as a result of the bending action from the bending unit 4. The unhindered movement of the frame 3 along the metal profile 2 is possible due to the wheels 9 being mounted on castor-swivels with a vertical swivel axle 10. The wheeled frame 3 is adjusting its orientation and velocity freely by the force exerted on the metal profile 2 and the counter force from the metal profile 2 which is fixed in the longitudinal direction, for example fixed in one end at a distance from the frame 3.

[0036] In order to perform the bending, the metal profile 2 is placed in the bending unit 4 on top of the frame 3, typically on top of a working platform 7, and in tangential abutment to the bending disc 5 and the two bending rollers 6. The bending disc 5 is displaced relatively to the bending rollers 6 towards the straight line 11 for thereby, during rotation of the bending disc 5, exerting pressure laterally onto the metal profile 2 and pressing the metal profile 2 into a bend towards a smaller bending radius. For example, the frame 3 is dragged only once along the metal profile 2, which typically is enough for the bending. However, in principle, the frame 3 can be dragged back and forth along the metal profile 2 a number of times in order to gradually decrease the bending radius of the metal profile 2; this is possible due to the free rolling of the frame 3.

[0037] As shown, the bending disc 5 and bending rollers 6 are arranged rotational about vertical axes 14, 12, which are normal to the flat ground support 9. This implies that the bending of the metal profile 2 is in a horizontal plane or substantially horizontal plane parallel to the ground support 9.

[0038] Prior to the placement of the metal profile 2 in the bending unit 4, the frame is moved to the fixed metal profile 2. In case that the frame 3 is not too large, the movement can be accomplished by manpower. For manual push and pull of the frame 3 on the flat ground support 9, a handle 13 is provided on the frame 3. Typically, the height of the handle 13 is between 0.6 m and 1.6 m, for example between 0.8 m and 1.2 m from the flat ground support 9, such as a plane floor in a building, in order to be convenient for manual push and pull. In case that the frame 3 is too heavy, the movement of the frame 3 to the metal profile 2 prior to insertion of the metal profile 2 in the bending unit 4 can be assisted by motor driven wheels and steering wheels.

[0039] As an example, which is illustrated in the figure, the machine 1 can be provided as an apparatus 24 comprising the bending unit 4, where the apparatus 24 is mounted onto a cart 25. This is an easy and low cost production principle.

[0040] The machine as illustrated in FIG. 1 can be used on metal profiles 2 that are fixed in the longitudinal direction, for example fixed at one end or the other or both, depending on the situation and the conditions. The longitudinal fixation need not be done at a first or second end of the metal profile, but can be done at any section of the metal profile 2. The frame 3 would move away from the fixed section or towards the fixed section for the bending of that part of the metal profile 2 that is remote from the fixed section.

[0041] FIG. 2 illustrates one possible working principle of the machine 1. FIG. 2a illustrates a starting position, where the frame 3 with the bending unit is positioned near the first end 2a of the metal profile 2. FIG. 2b illustrates the final bending situation, where the frame 3 with the bending unit has moved from the first end 2a of the profile 2 to the opposite, second end 2b of the metal profile 2 while bending the metal profile 2 during its travel along the metal profile 2. The metal profile 2 has its first end 2a fixed in a first fixture 27a, for example a clamp. This first fixture 27a is stationary in position but can turn which is indicated by bent double arrow in the figure. The turning of the first clamp 27a is used for following the angular change by the bending of the metal profile 2 during the bending process. The second end 2b of the metal profile 2 is fixed in a second fixture 27b, which is also turnable, as indicated by the bent double arrow; and the second fixture 27b is also translational in order to compensate for the changing distance between the two fixtures 27a and 27b when the metal profile 2 is bent, as illustrated in FIG. 2b. During the bending from the start situation in FIG. 2a to the final situation, as illustrated in FIG. 2b, the bending rollers 6 are adjusted for exerting the necessary bending pressure during the travel of the frame 3 along the longitudinally fixed metal profile 2.

[0042] For example, the metal profile 2 could extend through the fixture 27b and continue on the opposite side of the fixture 27b, which is illustrated by the hatched line 2'. As illustrated, the movement of the frame 3 along the metal profile 2 is towards the second fixture 27b, although this is not strictly necessary, because the machine 1 would also work by driving the frame 3 with the bending unit 4 in the opposite direction towards the first fixture 27a.

[0043] FIG. 3 is a further embodiment. Like elements as in FIG. 1 have the same numbers and are not repeated for convenience. The frame 3 comprises rollers 8 on the underside, where the rollers 8 are rolling on straight rails 26, such that the frame 3 with the bending unit 4 can only be moved along a straight line. In this case, the second end 2b of the profile is fixed to a fixation 27b. The first end 2a could be fixed in a movable fixture, but is here illustrated as not being fixed, as this is not strictly necessary, and the first end 2a and the free section 2" opposite to the fixed second end 2b can freely bend away from the frame 3 on the straight rails 26. It is pointed out that in this setup, the relative movement of the bending disc 5 and the guiding disc 15 along line 16 is not perpendicular to a line 11 that connects the centres of the bending rollers 6a and 6b.This is so, because the frame 3 is moving on straight rails 26 in parallel to the straight part of the metal profile towards the fixed second end 2b of the metal profile 2.

[0044] It is pointed out that the longitudinal fixation of the metal profile 2 need not to be done at the end 2b of the metal profile 2 but just some section of the metal profile. For example, the metal profile 2 could extend through the fixture 27b and continue on the opposite side of the fixture 27b, similarly to the illustration with the hatched line 2' in FIG. 2b.

[0045] Although, all the embodiments have been illustrated with a single frame 3 and bending unit 4, it is within the scope of the invention that more than one bending unit 4 is used. For example, two or more bending units 4 on movable frames 3 are provided in the machine 1. For example, two bending units move in opposite directions in order to increase the bending speed.

[0046] In another embodiment, two or more bending units are moving in the same direction on a single frame or on separate frames, one bending unit behind the other, in order to achieve a two-step bending of the metal profile, where the front bending unit is bending the metal profile into a bend with a first bending radius, and the second subsequent bending unit decreases the bending radius by bending the metal profile 2 even further.

1 machine

2 metal profile

2a first end of metal profile 2

2b second end of metal profile 2

3 frame

4 bending unit

5 bending disc, 5' upper part, 5" lower part

6 bending rollers

6a first bending roller

6b second bending roller

7 working platform

8 wheels

9 ground support

10 castor-swivel axis

11 line connecting the centres of the two bending rollers 6

12 rotational axle of bending roller 6

13 handle of frame

14 rotational axle of bending disc 5

15 guiding disc

16 line connecting centres of bending disc 5 and guiding disc 15

17 direction for potential lateral displacement of first bending roller 6

18 direction for potential lateral displacement of second bending roller 6

19 direction for potential lateral displacement movement of bending disc 5

20 direction for potential lateral displacement movement of guiding disc 15

21 motor

22 rails for bending rollers 6

23 direction of movement of the machine in the shown bending situation

24 bending apparatus

25 cart

26 rails

27a fixation of first end 2a at fixed position

27b fixation of second end 2b at movable position

Claims

1. A method for roll bending a bendable elongate metal profile (2) particularly a concrete reinforcing steel rod; the method comprising providing a machine (1); the machine (1) comprising a frame (3) and a bending unit (4) mounted on the frame (3); the bending unit (4) comprising a number of rollers (5, 15, 6) for positioning the metal profile between the rollers (5, 15, 6) such that pressure is exerted on the metal profile (2) by the rollers (5, 15, 6) at different locations on opposite sides of the metal profile (2), thereby causing bending of the metal profile (2) while the metal profile (2) is guided through the bending unit (4) by rotation of the rollers; wherein the frame (3) is provided movable on a support (9, 26); wherein the method comprises positioning the metal profile (2) between the rollers (5, 15, 6), longitudinally fixing the metal profile (2) against longitudinal movement and subsequently, while longitudinally fixed, moving the bending unit (4) on the support along the metal profile (2) and thereby causing bending of the metal profile (2), characterised in that the moving of the bending unit (4) along the profile (2) is caused by exerting a pushing or pulling force on the metal profile (2) along its longitudinal direction by the bending rollers (5, 15, 6) and thereby dragging the bending unit (4) along the metal profile (2).

2. A method according to claim 1, wherein the bending unit (4) comprising a bending disc (5) and two bending rollers (6) arranged in triangular configuration for taking up the metal profile (2) between the bending disc (5) and the two bending rollers (6) such that the bending disc (5) is on one side of the metal profile (2) and the two bending rollers (6) on the opposite side of the metal profile; wherein the bending disc (5) and the two bending rollers (6) are configured for mutually relative movement, the relative movement of the bending disc (5) being in a direction towards a straight line (11) connecting the two bending rollers (6); wherein the method further comprises placing the metal profile (2) on the frame (3) in tangential abutment to the bending disc (5) and the two bending rollers (6) and relatively displacing the bending disc (5) towards the straight line (11) for thereby exerting pressure laterally onto the metal profile (2) and pressing the metal profile (2) into a bent towards a smaller bending radius; by rotation the bending disc (5), driving the frame (3) with the bending unit (4) along the metal profile (2) while exerting bending pressure on the metal profile (2) by the bending disc (5) and the bending rollers (6).

3. A method according to claim 2, wherein each of the bending disc (5) and the bending rollers (6) is arranged rotational about a vertical axis (12); wherein the method comprises bending the metal profile (2) in a horizontal plane or substantially horizontal plane.

4. A method according to any preceding claim, wherein the frame (3) is provided on rails (26), and the method comprises fixing a section (2b) of the metal profile for preventing longitudinal movement of the metal profile (2); positioning the metal profile (2) in the bending unit (4) between the rollers (5, 15,6) and moving the frame (3) with the bending unit (4) along the profile (2) towards the fixed section (2b) and thereby bending the metal profile (2) by the bending unit (4).

5. A method according to claim 4, wherein the rails (26) are straight for a linear motion of the frame (3) along the rails (26); wherein the metal profile (2) comprises a free section (2") that is on an opposite side of the bending unit (4) relatively to the fixed section (2b), wherein that free section (2") is arranged for freely bending away from the bending unit (4).

6. A method according to claim 1, 2, or 3, wherein the frame (3) is provided with at least three wheels (8) for rolling on a flat, horizontal ground support (9) and each of the wheels (8) is mounted on a castor-swivel axis (10) on an underside of the frame (3) for free rolling and unhindered change of rolling direction of the frame (3) while on the ground support (9); wherein the method comprises providing the frame (3) with its wheels (6) in abutment to the ground support (9); causing unhindered rolling of the frame (3) on the ground support (9) and dragging of the frame (3) along the metal profile (2) through pushing or pulling force exerted on the metal profile (2) along its longitudinal direction by the bending unit (4) while the metal profile (2) is simultaneously bent in and by the bending unit (4).

7. A method according claims 6, wherein the metal profile (2) when positioned in the bending unit (4) has a first section (2a) on one side of the bending unit (4) and a second section (2b) on the opposite side of the bending unit(4); wherein first section (2a) is fixed in a first fixture (27a) that is stationary in position and turnable for following an induced bend in the profile (2); wherein the second section (2b) is fixed in a second fixture (27b) which is turnable and also translational in order to compensate for a changing distance between the two fixtures (27a) and (27b) when the metal profile (2) is bent; the method comprising bending the metal profile (2) while the frame (3) with the bending unit (4) is moving along the metal profile (2) towards the first fixture (27a) or the second fixture (27b).

8. A method according to claim 7, wherein the first section is a first end (2a) of the metal profile (2) and the second section is a second end (2b) of the metal profile.

9. A method according to any one of the claims 6, 7 or 8, wherein the method comprises providing the frame (3) at a distance from the metal profile (2), the distance being at least an order of magnitude larger than the largest of width or length of the frame (3); moving the frame (3) to the metal profile (2) by manually pushing or pulling the frame (3) and thereby causing rolling of the frame (3) on the flat ground support (9) towards the metal profile (2).

10. A method according to claim 9, wherein the frame (3) comprises a handle (13) for manual movement by push or pull of the machine (1) on the flat ground support (9), the handle being provided at a distance of between 0.6 m and 1.6 m from the plane.

11. A method according to any one of the preceding claims, wherein the bending unit (4) is provided on a top side of the frame (3).

12. A machine (1) for roll bending a bendable elongate metal profile (2), for example a steel rod, particularly a concrete reinforcing steel rod; the machine (1) comprising a frame (3) and a bending unit (4) mounted on the frame (3); the bending unit (4) comprising a number of rollers configured for positioning the metal profile between the rollers such that pressure exerted by the rollers (5, 15, 6) at different locations on opposite sides of the metal profile (2) causes bending of the metal profile (2) while the metal profile (2) is guided through the bending unit (4); wherein the frame (3) is provided with at least three wheels (8) for rolling on a support (9); characterised in that each of the wheels (8) is mounted on a castor-swivel axis (10) on an underside of the frame (3) for free rolling and unhindered change of rolling direction of the machine (3) on a flat, horizontal ground support (9) during bending of the metal profile in the bending unit when the metal profile is guided longitudinally through the bending unit by rotation of the rollers, causing the machine to be dragged along the metal profile by the force exerted on the metal profile (2) in its longitudinal direction by the rotation of the roller (5, 15, 6)s in case that the metal profile (2) is fixed with respect to its longitudinal direction; the wheels (8) spanning a plane that coincides with the ground support (9) when the machine is placed on such flat ground support (9).

13. A machine according to claim 12, wherein the bending unit (4) comprises a rotational bending disc (5) and two rotational bending rollers (6) arranged in triangular configuration for taking up the metal profile (2) between the bending disc (5) and the two bending rollers (6) such that the bending disc (5) is on one side of the metal profile (2) and the two bending rollers (6) on the opposite side of the metal profile; wherein the bending disc (5) and the two bending rollers (6) are configured for mutually relative movement, the relative movement of the bending disc (5) being in a direction towards a straight line (11) connecting the two bending rollers (6).

14. A machine according to claim 12 or 13, wherein the bending unit (4) is provided on a top side of the frame (3), the top side being opposite to the underside, and wherein the bending disc (5) is arranged rotational about an axis (14) that is normal to the plane and, thus, normal to the ground support (9) when the machine is placed on such ground support (9).

15. Use of a method or a machine according to any preceding claim for reinforcing a concrete construction by bending a concrete-reinforcing steel rod by the machine or method and moulding the bent steel rod into the concrete construction.

Drawing