EP1579930A1

EP1579930A1 - Bending device for bars

Info

Publication number: EP1579930A1
Application number: EP05101389A
Authority: EP
Inventors: Aldo Silvestri
Original assignee: OMES OFFICINE MECCANICHE Srl
Current assignee: OMES OFFICINE MECCANICHE Srl
Priority date: 2004-02-25
Filing date: 2005-02-24
Publication date: 2005-09-28
Anticipated expiration: 2025-02-24
Also published as: ATE374083T1; ITUD20040032A1; DE602005002579D1; EP1579930B1; ES2297615T3; DE602005002579T2

Abstract

Bending device (10) to bend at least a bar (11), for example metal, comprising fixed contrasting members (13), a bending support (15) mounted rotary around the fixed contrasting members (13) both in a clockwise and anti-clockwise direction, and a bending element (16) mounted radially on the bending support (15) in order to rotate therewith, so as to bend the bar (11), in cooperation with the fixed contrasting members (13). The bending support (15) defines a lying plane (P) on which the bar (11) is positioned. The device (10) also comprises movement elements which move the bending element (16) with respect to the bending support (15) between a first operating position, wherein the bending element (16) is at least partly above the lying plane (P), and a second retracted position wherein the bending element (16) is below the lying plane (P).

Description

FIELD OF THE INVENTION

The present invention concerns a bending device for bars, for example metal, comprising a contrasting element, a bending support or mandrel, mounted coaxial and rotary around the contrasting element, and a bending pin mounted radially on the mandrel and able to rotate with the latter, both in a clockwise and also in an anti-clockwise direction so that, in cooperation with the contrasting element it determines the bending of the bars for an angle of up to 180°, according to a desired geometric configuration.

BACKGROUND OF THE INVENTION

A bending device for metal bars is known, such as for example round pieces, profiles, tubular pieces or other, made for example from shearing methods, rolling, extrusion, profiling or otherwise.
The known bending device is normally mounted on bending machines downstream or upstream of a shearing assembly and/or drawing assembly and/or another bending assembly, and comprises a contrasting element around which a bending support or mandrel rotates, in both a clockwise and anti-clockwise direction. The bending support is generally disk-shaped and provided radially with a bending pin. The combined action of the fixed contrasting element and the bending pin rotating with the mandrel determines the bending of the bar.
It is known, in the state of the art, for example from US-A-3,857,271; US-A-4,456,036; WO-A-99/26739; EP-A-0379043; EP-A-0379030; EP-A-0538595; EP-A-0900602; DE-A-2723846 to bend a bar in a two-directional manner, that is first in one direction and then in the other, to conform it according to a desired geometry, for example S-shaped. In order to perform this operation it is necessary to take the bending pin first to one side, for example to the left, with respect to the longitudinal axis of the bar, in order to bend it to the right, and subsequently to the opposite side, in order to bend it to the left.
This operation entails the need to make the bending pin pass physically from one side of the bar to the other.
To this end it is known to move the mandrel together with the relative bending pin, between an operating position, wherein the latter interferes with the plane on which the bar lies, and a retracted position wherein the bending pin is also below the plane on which the bar lies so that, in this retracted position, a rotation of the mandrel determines the passage of the bending pin from one side of the bar to the other without interfering with the latter.
One of the main disadvantages of the known devices is that they are complex to design, to construct and to maintain, the complexity of the various mechanical members that determine the movement of the mandrel, associated with the fact that in any case it is necessary to guarantee the possibility of applying high torques in order to bend one or more bars at the same time, each one having diameters of as much as some tens of millimeters. This shortcoming entails an increase in the working times and production costs, and also of the dimensions of the bending device and the possible bending machines on which it is installed.
One purpose of the present invention is to achieve a bending device which allows to bend at least a bar, for example metal, with a diameter of as much as some tens of millimeters, both in one direction and also in two directions, without needing to provide complex movement members that allow the bending pin to pass from one side to the other of the bar to be bent.
Applicant has devised, tested and embodied this 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 main claim, while the dependent claims describe other characteristics of the invention, or variants to the main inventive idea.
In accordance with the above purpose, a bending device to bend at least a metal bar according to the present invention comprises fixed contrasting means, a bending support, mounted rotary around the fixed contrasting means, both in a clockwise direction and also in an anti-clockwise direction, and defining a lying plane on which the bar is able to be positioned, and at least a bending element, mounted on a supporting radius of the bending support, in order to rotate together with the latter, so as to bend the bar in cooperation with the contrasting means.
According to a characteristic feature, the bending device according to the present invention also comprises movement means able to move the bending element with respect to the bending support, between a first operating position, wherein it is at least partly above the plane on which the bending support lies, and a second retracted position wherein it is below said plane on which the bending support lies.
In this way, the movement necessary to allow the passage of the bending element below the bar takes place autonomously with respect to the bending support, thus simplifying the steps to design and construct the rotation members of the bending support.
This solution also facilitates a reduction in the maintenance times, and also the space occupied by the bending device when installed, giving benefits also in terms of production times and costs.
Advantageously, the movement means are arranged under the bending support, and comprises actuation means that move the bending element from the first operating position to the second retracted position.
According to a preferential form of embodiment of the bending device according to the present invention, the actuation means comprise a fixed guide and a lever element. In this embodiment, the lever element is hinged with a first end to the bending support and with a second end connected to the bending element, and is provided with sliding means, able to slide along the fixed guide. The latter comprises a circular supporting track, substantially plane, able to guarantee the secure positioning of the bending pin in its first operating position, and a circular sector with variations in height with respect to the lying plane, which functions as a command and return cam for the lever element, so that, when the sliding means meet the circular sector with variations in height, the bending element is moved from the first operating position to the second retracted position.
Advantageously, the circular sector with variations in height is positioned so as to take the bending element to the second retracted position when the latter crosses, in one direction or the other, an axis of feed of the bar.
In another preferential form of embodiment, the movement means of the bending device according to the invention comprise a linear actuator able to move the bending element perpendicularly to the lying plane from the first operating position to the second retracted position. In this embodiment, the bending element can be moved between the two positions, operating and retracted, in whatever angular position it may be in with respect to the bar to be bent.
With the bending device according to the present invention it is also possible to bend the bar both in one direction and in two directions, and particularly, bending in one direction it is possible to adopt mandrels with a diameter of up to about 400 mm, while bending in two directions mandrels of up to about 200 mm can be used.

BRIEF DESCRIPTION OF THE DRAWINGS

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

fig. 1 is a plane schematic view of the bending device according to the present invention;
fig. 2 is a section from II to II of fig. 1;
fig. 3 is a schematic lateral section of the bending device in fig. 1 in a first operating position;
fig. 4 is a schematic lateral section of the bending device in fig. 1 in a second retracted position;
fig. 5 is a schematic lateral section of a second form of embodiment of the bending device in fig. 1 in a first operating position;
fig. 6 is a schematic lateral section of a second form of embodiment of the bending device in fig. 1 in a second retracted position.

DETAILED DESCRIPTION OF SOME PREFERENTIAL FORMS OF EMBODIMENT

With reference to fig. 1, a bending device 10 according to the present invention is able to bend by a desired angle, in this case up to about 180°, one or more metal bars 11, having a diameter of up to about 40 mm.
The metal bar 11 is fed along an axis of feed "X" by a feed assembly, of a known type and not shown in the drawings, arranged upstream of the bending device 10.
The device 10 according to the invention comprises a fixed frame 12, substantially box-like in shape, a contrasting element 13, mounted substantially vertical and in a central position on the frame 12, a bending support, or mandrel 15, mounted axially rotary around the contrasting element 13 on an upper surface 12a of the frame 12, and a bending pin 16 mounted able to slide parallel to the axis of rotation of the mandrel 15 and on a radius of the latter. The bending pin 16 is also mounted rotary together with the mandrel 15 around the contrasting element 13, so that, in cooperation with the latter, it determines the bending of the metal bar 11.
The rotation of the mandrel 15 with respect to the contrasting element 13 is advantageously governed by revolving bearings 14, in this case roller bearings (figs. 3, 4, 5 and 6).
The bending device 10 also comprises, in this case, a temporary clamping gripper 17 (fig. 1), of a substantially known type and not described in detail, mounted on the upper surface 12a of the frame 12, and whose jaws 17a and 17b are arranged on opposite sides with respect to the axis of feed X of the metal bar 11, so as to temporarily clamp the latter during the positioning and bending steps.
To be more exact, the frame 12 comprises a supporting wall 20 (figs. 3 and 4) arranged below the mandrel 15, and to which the lower end of the contrasting element 13 is attached.
On the upper surface of the supporting wall 20 there is a plane track 21, substantially circular and interrupted in a sector underneath the axis of feed X, and a substantially circular command cam 23, arranged in this case inside the plane track 21 and provided, along one arc, with two plane segments 24 and 28 (fig. 2) arranged at different heights and connected by respective inclined planes 22.
On the supporting wall 20 (figs. 3 and 4) a drive member 25 is also mounted, of a known type and not described in detail, able to make the mandrel 15 rotate in one direction or the other around the contrasting element 13 by means of a toothed wheel kinematic mechanism 26.
The contrasting element 13 comprises, at its upper end, a pair of positioning pins 19, substantially cylindrical in shape, arranged on opposite sides with respect to the axis of feed X and separated from each other, so as to allow the positioning inside them, with little play, of the metal bar 11 to be bent. The positioning pins 19 can be selectively interchangeable, in a substantially known manner, with other pins of different size and shape, so as to allow a wide range of metal bars 11 to be located inside them, having different diameters, also arranged stacked vertically.
The mandrel 15 comprises a rotary disk 27 solidly connected to the kinematic mechanism 26 and lying on a plane "P" substantially parallel to the upper surface 12a of the frame 12. The rotary disk 27 comprises a through slot 29 oriented radially and in correspondence with which the bending pin 16 is arranged.
Inside the through slot 29 a supporting block 30 is arranged, able to slide perpendicularly to the plane P. The supporting block 30 is provided on its upper surface with a plurality of housing holes 31, in this case four, aligned radially and able to allow the bending pin 16 to be housed inside them at different radial distances from the contrasting element 13, in order to permit a wide range of bendings to be carried out.
To be more exact, the supporting block 30 slides inside the through slot 29 between a first operating position (figs. 3 and 5), wherein it positions the bending pin 16 above the lying plane P of the rotary disk 27, and a second retracted position (figs. 4 and 6), wherein it positions the bending pin 16 below said plane P.
Advantageously, on at least part of the outer surface of the supporting block 30 an annular wall 32 is arranged, made of a material with low friction coefficient, in order to facilitate the sliding between the two positions.
As shown in figs. 3 and 4, the sliding of the supporting block 30 is commanded by a command lever 33, which has a first end 35 hinged to the lower surface of the rotary disk 27, in a segment diametrically opposite the through slot 29, and a second end 36 connected in articulated manner to the lower surface of the supporting block 30, by means of a lever 37. On the second end 36 a wheel 39 is mounted axially rotary, able to rotate on the plane track 21 of the supporting wall 20 of the frame 12, when the bending pin 16 is above the plane P.
The command lever 33 also comprises a second wheel 40, mounted articulated in correspondence with the first end 35 and able to slide inside the command cam 23, in order to determine, as we shall see, the movement of the supporting block 30 from the first operating position to the second retracted position and vice versa.
The command lever 33 is advantageously shaped so as to be able to oscillate around its hinging point with the rotary disk 27, without interfering with the central part of the mandrel 15 and with the contrasting element 13.
The bending device 10 as described heretofore functions as follows.
Firstly, the supporting block 30 is in its first operating position, and keeps the bending pin 16 above the plane P on which the rotary disk 27 lies (fig. 3). In this first position, the wheel 39 rests on the plane track 21, while the second wheel 40 is released by the command cam 23. Moreover, with particular reference to fig. 1, the bending pin 16 is arranged on the left of the axis of feed X of the metal bar 11.
Once the two jaws 17a and 17b of the gripper 17 have been activated, so as to fix the position of the bar 11, the drive member 25 is activated, so as to make rotate the mandrel 15 and the relative bending pin 16 in a clockwise direction. In this way, the wheel 39 slides on the plane track 21, keeping the bending pin 16 above the plane P.
When the bending pin 16 contacts laterally the terminal part of the metal bar 11, it pushes the latter towards the right, bending it in correspondence with one of the two positioning pins 19. The diameter of the positioning pin 19 determines the radius of curvature of the bend performed.
The rotation of the mandrel 15 and the bending pin 16 is stopped once a terminal bending position is reached, as shown by a dash/double-dotted line and denoted in its entirety by the letter "A".
At this point the direction of rotation of the drive member 25 is inverted, so as to reposition the bending pin 16 in its starting position.
Then the jaws 17a and 17b of the gripper 17 are opened, and another segment of the metal bar 11 is fed.
If it is necessary to effect a new bend towards the left, it is necessary to take the bending pin 16 to the right of the axis of feed X of the metal bar 11.
This operation is carried out simply by rotating the mandrel 15 in an anti-clockwise direction, until the second wheel 40 enters inside the command cam 23. At this point, the second wheel 40 slides along the inclined plane 22 to pass from the plane segment 24 to the plane segment 28 and to draw, by means of the lever 33, the supporting block 30, taking it to its second retracted position. In this way, the bending pin 16 is positioned below the plane P. The bending pin 16 is then in a passage position "B", shown by a dash/double-dotted line, below and astride the metal bar 11.
Continuing the anti-clockwise rotation of the mandrel 15, the second wheel 40 progressively exits from the command cam 23 and, contrary to before, passes from the plane segment 28 to the plane segment 24, returning the supporting block 30 to its first operating position, and consequently the bending pin 16 above the plane P, left of the metal bar 11.
The device 10 according to the present invention thus allows to move the bending pin 16 with respect to the mandrel 15.
The leftward bend is hence performed as in the case of the rightward bend, with the sole difference of the direction of rotation of the mandrel 15 which, in this case, is opposite the previous one.
Figs. 5 and 6 show a second form of embodiment of the bending device 10 according to the present invention.
In this case second, the movement of the supporting block 30 and the relative bending pin 16 occurs by means of a linear actuator 41, while the bending pin 16 is in any case moved with respect to the mandrel 15 according to the characteristic of the present invention.
In this case, the linear actuator 41 is attached on one side to the lower end of the contrasting element 13, and on the other side to a movement plate 42 arranged below the supporting wall 20 of the frame 12.
The movement plate 42 comprises peripherally a plurality of guide and sliding shafts 43, in this case three, of which only two are shown here, arranged substantially vertical and able to slide through respective through holes 45 made on the supporting wall 20.
Advantageously, on the lower surface of the supporting wall 20 there are relative sliding bushings 46, arranged coaxially with said through holes 45, and able to facilitate and guide the sliding of the three shafts.
In the solution shown in figs. 5 and 6 an annular guide 47 is also provided, to which the upper ends of the three shafts 43 are screwed; the annular guide 47 is arranged substantially parallel to the plane P and below the supporting block 30.
Inside, the annular guide 47 defines a sliding seating 49 open towards the outside, and inside which a mating wheel 50 is able to slide, connected to the supporting block 30 by means of a rod 51.
In this way, when the drive member 25 makes the mandrel 15 rotate, the wheel 50 slides inside the sliding seating 49, keeping the position of the bending pin 16 constant with respect to the plane P.
In fact, in this second solution, it is the activation of the linear actuator 41 which determines the vertical movement of the annular guide 47 and consequently the sliding of the supporting block 30 inside the through slot 29, thus determining the positioning of the bending pin 16 interfering with, or below, the plane P.
With this solution it is possible to move the bending pin 16 independently of the mandrel 15, whatever angular position it might be in.
It is clear, however, that modifications and/or additions of parts may be made to the bending device 10 as described heretofore, without departing from the field and scope of the present invention.
It also comes within the field of the present invention to provide that the linear actuator 41 can be associated directly with the supporting block 30.
It also comes within the field of the present invention to provide that the bending pin 16 can be connected directly to the movement means, without needing any supporting block 30.
According to a variant, the plane track 21 and the command cam 23 can be made in a single piece and coinciding on the same diameter. In this embodiment, only one of the two wheels 39 or 40 is sufficient, in order to determine the movement of the pin 16 in its two positions.
According to another variant, instead of being circular the command cam 23 extends only for a limited arc of several tenths of a degree.
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 device for bars, all of which shall come within the field and scope of the present invention.

Claims

Bending device to bend at least a bar (11), for example metal, comprising fixed contrasting means (13), a bending support (15) rotatably mounted around said fixed contrasting means (13) both in a clockwise and anti-clockwise direction, said bending support (15) defining a lying plane (P) on which said bar (11) is able to be positioned, and at least a bending element (16) mounted radially on said bending support (15) in order to rotate therewith, so as to bend said bar (11), in cooperation with said fixed contrasting means (13), movement means able to move said bending element (16) with respect to said bending support (15) between a first operating position, wherein said bending element (16) is at least partly above said lying plane (P), and a second retracted position, wherein said bending element (16) is below said lying plane (P), wherein said movement means are arranged below said bending support (15) and comprise actuation means (33, 41) able to move said bending element (16) from said first operating position to said second retracted position, characterized in that said actuation means comprise fixed guide means (21, 23), and a lever element (33) hinged with one end (35) to said bending support (15) and connected with a second end (36) to said bending element (16, 30), said lever element (33) being provided with sliding means (39, 40) able to slide along said fixed guide means (21, 23).
Device as in claim 1, characterized in that said fixed guide means comprise at least a circular sector (23) provided with variations in height with respect to said lying plane (P), and able to function as a command and return cam, wherein said sliding means (40) are able to slide, in order to move said lever element (33) and said bending element (16) between said first operating position and said second retracted position.
Device as in claim 2, characterized in that said fixed guide means comprise a substantially plane circular track (21) on which said sliding means (39) are able to slide in order to selectively maintain said bending element (16) in said first operating position.
Device as in claim 2 or 3, characterized in that said circular sector (23) is made in correspondence with a longitudinal axis of feed (X) of said bar (11), lying on said lying plane (P) or parallel thereto, so that said bending element (16) moves into said second retracted position when it passes in one direction or the other said axis of feed (X).
Device as in claim 3, characterized in that said sliding means comprise a first wheel (39) connected to said second end (36) of said lever element (33) and able to slide on said circular track (21), and a second wheel (40) connected to said lever element (33) near said first end (35) and able to slide inside said circular sector (23).
Bending device to bend at least a bar (11), for example metal, comprising fixed contrasting means (13), a bending support (15) rotatably mounted around said fixed contrasting means (13) both in a clockwise and anti-clockwise direction, said bending support (15) defining a lying plane (P) on which said bar (11) is able to be positioned, and at least a bending element (16) mounted radially on said bending support (15) in order to rotate therewith, so as to bend said bar (11), in cooperation with said fixed contrasting means (13), movement means able to move said bending element (16) with respect to said bending support (15) between a first operating position, wherein said bending element (16) is at least partly above said lying plane (P), and a second retracted position, wherein said bending element (16) is below said lying plane (P), wherein said movement means are arranged below said bending support (15) and comprise actuation means (33, 41) able to move said bending element (16) from said first operating position to said second retracted position, characterized in that said actuation means comprise a linear actuator (41) able to move, parallel to said bending support (15), an annular guide (47) arranged below the said bending support (15), said annular guide (47) being connected to said bending element (16) by means of connection means (50, 51).
Device as in claim 6, characterized in that said linear actuator (41) comprises a first part fixed to a lower end of said fixed contrasting means (13), and a second part movable parallel with respect to said first part and fixed to said annular guide (47) by means of a movement plate (42), and one or more guide shafts (43) arranged substantially perpendicular to said lying plane (P).
Device as in claim 6 or 7, characterized in that said annular guide (47) comprises a sliding seating (49), and that said connection means comprise a wheel (50) able to slide in said sliding seating (49) and connected to said bending element (16) by means of a rod (51).
Device as in any claim hereinbefore, characterized in that said bending element comprises a bending pin (16) able to be inserted in a supporting block (30) arranged radially on said bending support (15), said supporting block (30) being provided with a plurality of housing holes (31), in each of which said bending pin (16) is able to be removably positioned.
Device as in claim 9, characterized in that said bending support (15) comprises a through radial slot (29), inside which said supporting block (30) is able to slide perpendicularly to said lying plane (P).
Device as in claim 10, characterized in that on at least part of the sides of said supporting block (30) sliding means (32) are arranged, made of a material with a low friction coefficient.
Device as in any claim hereinbefore, characterized in that said fixed contrasting means (13) comprise at least two positioning pins (19) substantially equidistant from the axis of rotation of said bending support (15), so that said metal bar (11) to be bent is able to be positioned between them.
Device as in any claim hereinbefore, characterized in that it also comprises temporary clamping means (17) able to selectively retain said bar (11) during the bending steps.