"BENDING MACHINE FOR OBLONG METAL ELEMENTS, AND RELATIVE METHOD"

FIELD OF THE INVENTION The present invention concerns a bending machine for oblong metal elements to be shaped, such as for example reinforcement bars, sheets, round pieces, sections, tubes or others, made for example from drawing, rolling, extrusion, profiling or other operations, with diameters or thicknesses that range from about 5 mm to about 45 mm. In particular, the bending machine according to the invention comprises at least a bending unit and a contrasting unit around which the bending unit effects the shaping of the oblong metal element.

BACKGROUND OF THE INVENTION

Bending machines are known, for oblong metal elements to be shaped, such as for example reinforcement bars, sheets, round pieces, sections, tubes or others, made for example from drawing, rolling, extrusion, profiling or other operations. Known bending machines essentially consist at least of a bending support, or mandrel, generally disk-shaped, defining a bending plane and provided centrally with a contrasting element. On one radius of the mandrel a bending pin is provided, substantially co-planar with the contrasting element. The bending pin is able to rotate, in both a clockwise and anti-clockwise direction, around the contrasting element, so that the shaping of the oblong metal element occurs due to plastic deformation around the contrasting element.

In the field of shaped bars for reinforcement, and in other fields, there is a known need to make special pieces having a sequence of bends of different diameters and/or shapes.

In order to perform this operation, in any case guaranteeing the quality of the bend and respect for legislative norms, for example in the building trade, it is necessary to replace on each occasion the contrasting element with a different one, suitable for the specific diameter of the bend. It is known to perform this operation using cranes, gantries or similar lifting devices, to remove the contrasting element, or the whole bending plate, and to replace it with another having different sizes and/or shape, according to the type of bend to be made.

This operation, apart from being particularly dangerous and difficult for the workers, requires the intervention of specialized personnel and entails long intervention times with the machine stopped.

In known machines, in order to guarantee the positioning of a large number of different contrasting elements, the mandrel is also very large, with a consequent increase in costs and the installation bulk of the machine.

Furthermore, the various unused contrasting elements must be stored apart, occupying further space for the installation.

One purpose of the present invention is to achieve a bending machine which allows to bend at least a bar, for example metal, with different bending diameters and/or shapes, without needing to provide long and complex steps to replace the contrasting elements, and without using lifting devices such as cranes, gantries or suchlike.

Another purpose of the present invention is to achieve a bending machine in which replacing the contrasting elements does not entail an increase in the overall bulk of the machine, and the need to provide external stores to position the unused contrasting elements.

Another purpose of the present invention is to achieve a bending machine which can perform not only circular bends, but substantially of any shape and size.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purposes, a bending machine according to the present invention is applied to bend oblong metal elements and comprises a contrasting unit, a bending support defining a bending plane "P" on which the oblong metal element is able to be positioned, and at least a bending unit, mounted mobile around the contrasting unit so as to bend the oblong metal element in cooperation with the contrasting unit.

According to a characteristic feature of the present invention, the contrasting unit comprises a plurality of contrasting elements having different shapes and sizes, and support and movement means with which the contrasting elements are associated, and able to position a determinate one of said contrasting elements in correspondence with a determinate operative bending position.

Each contrasting element is selectively positionable between a lowered inactive position, completely below said bending plane, and a raised bending position substantially co-planar with said bending plane.

In this way, each contrasting element can selectively be replaced by another, therefore without requiring the intervention of external lifting devices such as cranes, gantries or suchlike.

With the present invention, the operations to replace the contrasting element occur substantially automatically and do not necessarily require the intervention of specialized manpower. Furthermore, providing the plurality of contrasting elements directly on board the machine allows to reduce the overall installation bulk, since it is no longer necessary to provide an external store to contain the unused contrasting elements.

According to a variant, each contrasting element is selectively movable between said first position and said second position, in an independent manner with respect to said support and movement means.

According to another variant, the contrasting elements are movable between the first position and the second position in a coordinated manner with the support and movement means.

Each contrasting element comprises a pair of contrasting cylinders having equivalent diameter, while the support and movement means comprises one or more mobile support plates on which the contrasting cylinders are mounted.

According to another variant, the support and movement means is conformed so that, in the lowered position, the support plate and the contrasting cylinders are completely below the bending plane "P", and free the bending plane so as to allow the positioning of a different contrasting element.

Furthermore, the support and movement means is conformed so that, in the raised position, the support plate or plates are substantially co-planar with the bending plane "P" and the contrasting cylinders are completely above the

bending plane "P", so as to be able to cooperate with the bending unit and to make the bend on the oblong metal elements.

According to another variant, each contrasting element comprises at least a positioning bushing, while the bending plane comprises at least a positioning pin which, in the raised position, is inserted in the positioning bushing.

In this way, a desired reciprocal positioning is defined between the contrasting element and the bending plane during the bending operations. Advantageously, the coupling of the bushings and the positioning pins is effected with ample play.

According to a variant, the machine also comprises at least a lifting member disposed in correspondence with said determinate operative bending position in order to move said determinate contrasting element between said lowered position and said raised position.

According to another variant, the support and movement means comprises, for every contrasting element, at least a lifting member, to lift it and lower it vertically with respect to the bending plane "P".

According to another variant, the support and movement means also comprises a rotary store in which, angularly offset with respect to each other, the contrasting elements of different sizes and/or shapes are positioned; the rotary store is disposed completely below the bending plane "P" and is able to be rotated so as to selectively position a determinate contrasting element in correspondence with the determinate operative bending position.

According to another variant, the support and movement means comprises a linearly mobile store in which the contrasting elements of different sizes and/or shapes are positioned, in sequence; the mobile store is disposed completely below the bending plane "P" and is able to selectively position a determinate contrasting element in correspondence with the determinate operative bending position.

In a first embodiment, the mobile store is conformed so as to move linearly in a direction substantially parallel to the axis of feed X of the oblong metal elements.

In an alternative embodiment, the mobile store is conformed so as to move transversely with respect to the axis of feed X of the oblong metal elements.

In all said embodiments, the mobile store is conformed to be selectively

extracted laterally from the bulk of the bending plane, so as to facilitate maintenance and cleaning operations.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a schematic view from above of a first form of embodiment of a bending machine according to the invention;

- fig. 2 is a schematic lateral view of the machine in fig. 1 ; - fig. 3 shows an enlarged detail of fig. 2;

- figs. 4a, 4b, 4c and 4d show a sequence of changing the contrasting cylinders of the bending machine according to the present invention;

- figs. 5a, 5b, 5c, 5d, 5e and 5f show a sequence of bending steps made with the bending machine according to the present invention; - fig. 6 is a schematic view from above of a second form of embodiment of a bending machine according to the invention;

- fig. 7 is a schematic lateral view of the machine in fig. 6;

- fig. 8 is a schematic view from above of a third form of embodiment of a bending machine according to the invention; - fig. 9 is a schematic lateral view of the machine in fig. 8.

DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF

EMBODIMENT

With reference to fig. 1, a bending machine 10 according to the present invention is able to bend by a desired angle, up to 180° and more, in this case one or more metal bars 11, with a diameter of up to about 40 mm.

The metal bar 11 is fed along an axis of feed "X" by a feed unit, of a known type and not shown in the drawings, disposed upstream of the bending machine 10.

The machine 10 according to the invention comprises a fixed frame 12 which defines a bending plane "P", a contrasting element 13, mounted substantially vertical on the frame 12, and a bending unit 15 mobile with respect to the contrasting element 13 on a plane substantially parallel to and above the bending plane "P".

The bending unit 15 comprises a bending pin 16 mounted mobile perpendicularly to the bending plane "P", and a pair of movement arms, respectively a first 17 and a second 19, which move the bending pin 16 parallel to the bending plane "P". The movement of the bending pin 16 substantially perpendicular to the bending plane "P" is actuated by a linear actuator 20.

The linear actuator 20 is mounted at one end of the second 19 of the two movement arms, so as to allow the selective positioning of the bending pin 16 between a first bending position, lowered, in which it is substantially co-planar with the contrasting element 13, and a second movement position, raised, in which it is raised with respect to the contrasting element 13.

In this way, in its first bending position and in combination with the contrasting element 13, the bending pin 16 bends the metal bars 11 whereas, in its second movement position, due to the effect of the movement imparted by the movement arms 17 and 19, it passes above the metal bars 11 disposed on the bending plane "P".

The first movement arm 17 is mounted sliding on a raised structure of the frame 12, in this case in a direction substantially parallel to the axis of feed "X" of the metal bars 11. In particular, the first movement arm 17 comprises a first movement plate 22 mounted sliding along a corresponding beam 23 of the raised structure 21.

The beam 23 comprises laterally two sliding guides 25 (fig. 3) with a substantially trapezoid section, on which coordinated sliding blocks 26 slide, solid with the first movement plate 22. The substantially trapezoid and coordinated shape of the sliding guides 25 and the sliding blocks 26 not only allows a precise linear sliding, but also guarantees the stable coupling of the first movement plate 22 and the beam 23, even in the event that the bending requires substantially high torques.

The first movement arm 17 also comprises a first actuator member 27 (figs. 1 and 2) attached on one side to the beam 23 and on the other side to the first movement plate 22.

The second movement arm 19 is mounted sliding on the first movement arm 17, in this case, in a direction substantially parallel to the axis of feed "X" of the

metal bars 11.

In particular, the second movement arm 19 comprises a second movement plate 29 mounted sliding on a lower surface of the first movement plate 22.

The first movement plate 22 comprises laterally two sliding guides 30 with a substantially trapezoid section, on which coordinated sliding blocks 31 slide, solid with the second movement plate 29.

In this case too, the substantially trapezoid and coordinated shape of the sliding guides 30 and the sliding blocks 31 not only allows a precise linear sliding, but also guarantees the stable coupling of the second movement plate 29 and the first movement plate 22, even in the event that the bending requires substantially high torques.

The second movement arm 19 also comprises a second actuator member 32 attached on one side to the first movement plate 22 and on the other side to the second movement plate 29. The bending machine 10 also comprises, in this case, two clamping grippers

33, of a substantially known type and not described in detail here, mounted upstream and downstream of the contrasting element 13, and whose jaws are disposed on opposite sides with respect to the axis of feed "X" of the metal bars 11, so as to clamp the latter temporarily during the positioning and bending steps. In this case, the contrasting element 13 can be selectively replaced by other analogous contrasting elements 13 having different shape and size.

In this way, the metal bars 11 can be bent with different bending radii and shapings.

With particular reference to the embodiment shown in figs. l to 3, each contrasting element 13 comprises a pair of contrasting cylinders 35 having an equivalent diameter.

The two contrasting cylinders 35 are mounted on a support plate 36 so as to be reciprocally distanced to define a housing interspace for the metal bars 11.

Each support plate 36 can be selectively associated with the fixed frame 12 by positioning the support plate 36 in a corresponding positioning aperture 37 made on the frame 12.

Furthermore, each support plate 36 comprises four positioning bushings 39 in which, in a position when the support plate 36 is coupled to the frame 12,

coordinated positioning pins 40 are able to be inserted (figs. 4a-4d).

The positioning pins 40 are advantageously mounted facing downward on a lower surface of the frame 12 and have an ample coupling play, for example 3 mm, with the relative positioning bushings 39. In this way, the possibility of metal slag and/or other impurities depositing on the positioning pin 40 and/or the positioning bushing 39, which would compromise the correct coupling of the two, is reduced to a minimum.

Each support plate 36 is associated at the lower part with a lifting member 41, for example hydraulic, in order to lift it and lower it vertically, with the relative contrasting cylinders 35, with respect to the bending plane "P".

In this way, the support plate 36 is selectively moved between a lowered position, in which both the support plate 36 and the contrasting cylinders 35 are completely below the bending plane "P", and a raised position, in which the support plate 36 is substantially co-planar with the bending plane "P" and the contrasting cylinders 35 are completely above the bending plane "P"

In the raised position, the positioning pins 40 are inserted in the positioning bushings 39.

The bending machine 10 also comprises a store 42, in which the support plates 36 are positioned, each having a relative pair of contrasting cylinders 35 of different size and/or shape.

In particular, the store 42 comprises a rotary cart 43 (figs. 1, 2 and 3) disposed completely below the bending plane "P" and on which all the support plates 36 are mounted, angularly offset with respect to each other, with the relative contrasting cylinders 35 and lifting members 41. In this way, the rotary cart 43 is selectively rotated until it positions a determinate support plate 36 in a position of alignment with the positioning aperture 37 of the frame 12.

From this condition, the lifting member 41 takes the relative support plate 36 directly from the lowered position to the raised position. According to the form of embodiment shown in figs. 6 and 7, the rotary cart

142 is replaced by a mobile cart 143, conformed to move linearly in a direction substantially parallel to the axis of feed "X" of the metal bars 11.

In this case, the mobile cart 143 is moved laterally with respect to the axis of

feed "X" and the lifting member 41 is conformed so as to move the relative support plate 36 laterally into alignment with the positioning aperture 37, before it is lifted to the raised position.

According to the form of embodiment shown in figs. 8 and 9, the mobile cart, denoted generally by the reference number 243, is disposed in a direction substantially transverse to the axis of feed "X" of the metal bars 11.

In this case, the mobile cart 243 moves the support plates 36 directly below the positioning aperture 37, so that the lifting member 41 can lift the relative support plate 36 directly into the raised position. In both embodiments, that is, with the rotary cart 43 and the mobile cart 143 or 243, the whole cart 43, 143, 243 is positioned on the ground sliding on relative rails 44, so that the cart 43, 143, 243 can be removed outside the bulk of the fixed frame 12 and thus intervention and maintenance operations can be performed with greater freedom and safety. The bending machine 10 according to the present invention functions as follows.

Initially, the linear actuator 20 keeps the bending pin 16 in its second movement position, above the metal bars 11.

From this second raised position, depending on the type of bend to be made, the bending pin 16 is selectively moved co-planar to the bending plane "P" and with respect to the contrasting element 13 by means of the reciprocal movement of the two movement arms 17 and 19, until a specific starting position is reached.

With particular reference to figs. 1 and 2, the bending pin 16 is shown in a continuous line, to the right of the axis of feed "X" of the metal bars 11 and, in a line of dashes, to the left of the axis of feed "X" of the metal bars 11.

Once the specific starting position has been reached with respect to the contrasting element 13, the bending pin 16 is taken to its first bending position substantially co-planar to the contrasting element 13.

Once the two jaws of the relative clamping grippers 33 have been activated, so as to fix the position of the bars 11, the two actuator members 27, 32 of the two movement arms 17 and 19 are activated in a coordinated manner, so as to make the bend on the metal bars 11, to the left or to the right, around the relative contrasting element 13.

Furthermore, thanks to the movement made by the two movement arms 17 and 19, the bending pin 16 can be positioned, both before and also during the bending, substantially in any position with respect to the contrasting element 13, and can thus make shapings of the metal bars 11 substantially of any shape. The diameter and/or shape of the contrasting element 13 determines the radius and/or shaping of the bend made.

If it is necessary to change the sizes of the contrasting element 13 in order to make a different bend, the support plate 36 to be replaced is taken by the relative lifting member 41 to its lowered position. Then, the respective rotary cart 43 (figs. 1-3) or mobile cart 143, 243 (figs. 6- 9) is rotated or translated until it takes the support plate 36 with the desired contrasting cylinders 35 into correspondence with the positioning aperture 37.

Once this position has been reached, the relative lifting member 41 lifts the support plate 36 from its lowered position to its raised position, to take the relative contrasting cylinders 35 to an operation condition for bending.

Since it is carried out substantially automatically, this operation does not require an intervention of the workers, nor long downtimes of the equipment of the machine, allowing to bend metal bars 11 with different bending radii as shown for example in the sequence in figs. 5a-5f. It is clear, however, that modifications and/or additions of parts or steps may be made to the bending machine 10 as described heretofore, without departing from the field and scope of the present invention.

For example, it comes within the field of the present invention to provide that the sliding blocks 26 and 31, and the coordinated sliding guides 25 and 30, have a cross section of a different shape, other than trapezoid, but in any case suitable to support high bending torques.

It is also clear that, although the present invention has been described with reference to specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of bending machine for bars, particularly for bars fed from a coil, and the relative method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.