EP1804981B1 - Sheet metal bending machine and production line incorporating a machine of this type - Google Patents

Abstract

A roll bender machine for bending metal sheets which includes a roller driven in rotation and about which the sheet metal is rolled and at least two backing rollers adapted to receive and bear against a sheet while it is being bent around the roller. The backing rollers are mounted to rotate on a support that is adjustable. The bending roller and backing rollers are each associated with at least one set of devices for compensating their deflection. An arm is mounted on the machine for receiving coiled sheet metal and is provided with a housing in which the bending roller is at least partially received.

Description

The invention relates to a sheet-bending machine and, more particularly, to a roll-type machine according to the preamble of claim 1. The invention also relates to a machine for manufacturing tubes or rolls by bending sheet metal, this installation incorporating a bending machine. The term "rolling machine" designates all the machines making it possible to produce a tube or a shell from a metal plate of small thickness, in particular of a sheet. The production of tubes or ferrules from sheets is carried out by bending, that is to say by curving the sheet according to a radius of curvature corresponding to that of the tube or ferrule. In particular, the invention relates to rollers for making tubes or ferrules with the smallest possible diameter as a function of the length of the tube and the thickness of its wall; for example tubes 60 mm in diameter for a length of about 1 meter and a thickness of 0.5 mm.

We know, by FR-B-2 750 061 , rollers comprising a bending roller, driven in rotation and around which the sheet is wound, and two support rollers, parallel to the bending roller, which allow to provide an adjustable passage between the different rollers, so as to guide and give the desired radius of curvature to the sheet. The outer diameter of the bending roller governs the minimum diameter of the tube or shell that can be obtained in one revolution with the rolling machine. The internal diameter of the tube or ferrule thus formed varies in particular as a function of the elastic limit of the metal or of the metal alloy of the sheet: the higher this limit, the greater the final diameter of the tube, the sheet metal tending to return to its original form. For example, for ordinary steels, the minimum diameter of the tube is about 1.2 times the diameter of the bending roll. For titanium, which has a high yield strength, the minimum diameter of the tube is about 5 times the diameter of the bending roll. To make a stainless steel tube with an internal diameter of 80 mm, as used for chimney flues, the diameter of the bending roller must be 1.4 times smaller, that is to say close to 55 mm .

Given the constraints it undergoes during a rolling operation, a bending roller of this diameter, a length close to one meter, does not remain rectilinear, but tends to have a large arrow. Likewise, the support rollers tend to have an arrow. This deflection problem can also be accompanied, depending on the stresses exerted by the sheet, a start twisting of the bending roller.

In the case where the bending and support rollers have an arrow, the tube is curved in the middle. We talk about "barrel shape".

FR-B-2 750 061 discloses a solution for resolving the deflection of the support rollers by the use of a plurality of aligned low-length support rollers, or, alternatively, support rollers of length close to that of the bending roll which rely on several small rolls.

EP-A-0477751 describes an upper roll and a lower roll, the latter being flanked by two parallel rollers. Adjustable rollers carried by beams and movable in sliders, come to adjustable support on the rollers located in the lower part to compensate their arrow.

These devices make it possible to compensate for the single arrow of the support rollers. This compensation is not controlled and the arrow of the bending roller is not compensated. Such a system does not allow to obtain really cylindrical tubes with a diameter of about 80 mm for a length of about 1.20 meters.

It is to this disadvantage that the invention more particularly intends to remedy by proposing a rolling machine adapted to the production of tubes of high length / diameter ratio and cylindrical.

To this end, the subject of the invention is a sheet-type bending machine, of roll type, according to claim 1.

Such a roller makes it possible to compensate, in a coordinated manner, the arrows of the different rollers and thus to form cylindrical tubes.

Preferential embodiments are described in the dependent claims.

The invention also relates to a line for manufacturing tubes or cylinders by bending sheet metal comprising at least one sheet bending machine made according to one of the previous embodiments.

• la figure 1 est une vue en perspective, simplifiée, d'une machine conforme à un mode de réalisation de l'invention, une tôle étant représentée avant cintrage, en traits mixtes,
• la figure 2 est une coupe partielle selon le plan Il de la partie supérieure de la machine représentée à la figure 1, pour plus de clarté seul trois jeux de moyens de maintien du rouleau de cintrage et trois jeux de moyens de compensation d'un rouleau d'appui sont représentés,
• la figure 3 est une vue de dessous, partielle et en perspective, du rouleau de cintrage et de certains moyens de compensation de sa flèche,
• la figure 4 est une coupe partielle à plus grande échelle selon la ligne IV-IV à la figure 1,
• la figure 5 est une section longitudinale partielle, à une échelle différente, selon la ligne V-V à la figure 4 d'un système de maintien du rouleau de cintrage dans un organe de compensation de la flèche,
• la figure 6 est une vue en perspective d'un jeu de moyens de compensation de la flèche des rouleaux d'appui, la rainure dans laquelle repose cette pièce étant représenté en traits mixtes et
• les figures 7 à 9 sont des schémas illustrant les différentes phases du cintrage d'une tôle.

The invention will be better understood and other advantages thereof will appear more clearly on reading the following description of an embodiment of a sheet bending machine according to the invention, given only to by way of example and with reference to the appended drawings in which:

• the figure 1 is a perspective view, simplified, of a machine according to an embodiment of the invention, a sheet being shown before bending, in phantom,
• the figure 2 is a partial section along the plane II of the upper part of the machine represented in figure 1 for the sake of clarity only three sets of means for holding the bending roller and three sets of means for compensating a support roller are shown,
• the figure 3 is a bottom view, partial and in perspective, of the bending roller and some means of compensation of its arrow,
• the figure 4 is a partial section on a larger scale along line IV-IV at figure 1 ,
• the figure 5 is a partial longitudinal section, on a different scale, along line VV to figure 4 a system for holding the bending roller in an element for compensating the boom,
• the figure 6 is a perspective view of a set of means for compensating the deflection of the support rollers, the groove in which this piece rests being shown in phantom and
• the Figures 7 to 9 are diagrams illustrating the different phases of the bending of a sheet.

The machine for bending the sheets 1, called the rolling machine, represented in FIG. figure 1 comprises a main body 2 generally configured in H. The spacing between the posts 3, 4 of the H is adapted to the final length of the tube T that is desired to achieve. The crossbar 5 of the body 2 of the machine supports a cross-member 6 fixed held generally horizontal. This crosspiece 6 is provided on its upper face with three notches 7, inclined at about 45 ° with respect to a longitudinal axis A of the crossbar 5. The cross member 6 is movable longitudinally, by a hydraulic device 60, in a direction parallel to the axis A.

A second crosspiece 9, equipped on its underside with at least two shims 8, is placed on the crosspiece 6. Thus, when moving simultaneously from right to left or from left to right at the figure 2 , the crosspiece 6, the shims 8 by sliding on the slope of the notches 7 on which they rest, raise or lower the cross member 9, in a direction generally perpendicular to the axis A and parallel to the plane of the figure 2 . By this device, one transforms a horizontal movement in vertical movement.

The cross member 9 is equipped on its upper face with a longitudinal groove. For clarity, this groove is shown in phantom at the figure 6 . Members 11 of means for compensating the deflection of the support rollers are partially engaged in this groove 10 and are movable therein.

Each of the members 11 or games, comprises a main body 12 generally configured U flat bottom. The inner face 13 of the bottom is inclined. A sloped shim, or "wedge" 14 whose inclined face has a slope substantially identical to that of the face 13, is positioned on the bottom of the main body 12. A frame 15 is placed on the upper face of the shim 14. frame supports three ball bearings 16 juxtaposed and whose axes of rotation X ₁₆ are parallel and oriented in a direction generally perpendicular to the plane of the figure 4 . The ball bearings 16 thus form a raceway generally parallel to the slope of the bottom 13.

A setting device 17 comprising a micrometer screw 17A and equipped with a counter 17B is mounted on a wing of the body 12. The device 17 is not shown in FIG. figure 4 for the clarity of the drawing. The end of the screw 17A is connected to an edge of the sloping wedge 14. Thus, by screwing or unscrewing the screw 17A, the end of the latter penetrates more or less into the space between the wings of the body 12 and pushes the shim 14 towards the other wing of the body 12. This displacement F ₁ of the shim 14 is on the inclined face of the bottom 13, which has the effect of raising or lowering the frame 15 which is placed on the upper face of the wedge 14. This vertical movement is represented by the double arrow F ₂ at the figure 4 .

A relief 18 is projecting on the outer face of the bottom 13A. It is of a form adapted to fit, to play reduced, and to slide in the groove 10 of the cross member 9. The spacing of the members 11 is adjusted so that, when in position in the groove 10, the ball bearings 16 are evenly spaced, parallel to the axis A.

Two cylindrical rods 19 of circular section, solid or hollow, preferably made of a metal or an alloy of stainless metals are disposed on the raceway formed by the ball bearings 16. These two rods constitute the support rollers 19 of the machine. They are mounted free in rotation while being held by their ends in housings formed in vertical uprights secured to the cross member 9. The support rollers 19 are arranged so that, at each member 11, each roller 19 is supported by two ball bearings 16 juxtaposed. In this configuration, the longitudinal axes X ₁₉ of the rollers 19 and the longitudinal axes X ₁₆ of the ball bearings 16 are generally parallel to the axis A of the crosspiece 6. The rollers 19 and the ball bearings 16 are driven by compared to others in rotation by friction.

The upper part of the main body 2 of the machine receives the bending roller 20 around which winds the sheet when bent. The X axis ₂₀ of the roll 20 is disposed in a direction generally parallel to the axis A The roll 20 is kept as straight as possible by means of compensation of its arrow.

These means of compensation of the arrow comprise an arm 21 of cylindrical outer shape, solid, circular section, made of a rigid material. This arm 21 has a high elastic inertia that is to say that it remains generally rectilinear or, at least, it has a low deflection when it is subjected to stress, in particular a bending force. Advantageously, its outer diameter is generally between three and six times that of the bending roller 20.

This arm 21 is provided, over substantially its entire length, with a longitudinal groove 22. The groove 22 is flat-bottomed. The width of this groove 22 is substantially greater than the diameter of the bending roller 20.

This groove 22 is adapted to receive organs providing a bearing contact between the roller 20 and the arm 21.

Several support subassemblies 23 of the roll 20 are distributed along the length of the groove 22. Three subassemblies 23, which is a minimum, are represented in FIG. figure 2 but their number is variable and chosen during the design of the rolling machine 1.

Within each subassembly 23, rollers 23A are mounted on a cradle 23B. This cradle 23B has a generally U-shaped flat bottom. The dimensions and the external shape of the cradle 23B are adapted to those of the groove 22. The shapes and internal dimensions of the cradle 23B are adapted to marry, without contact, the circumference of the roll 20.

The figure 5 is a section in two different planes of the cradle 23B passing, on the one hand in the median plane of the cradle 23B (left part of the figure) and, on the other hand, in the median plane of a support axis 26 of a roller 23A (right part of the figure).

The rollers 23A are mounted, in pairs, on each cradle 23B. A screw 25 passes through the bottom of the cradle 23B and fixes the latter at the bottom of the groove 22. When the cradles 23B are in place in the groove 22, the rollers 23A are each free to rotate about an axis 26 maintained in two bearings 23C formed in the cradle 23B. The axes 26 are oriented in a direction parallel to a longitudinal axis X ₂₂ of the groove 22.

The groove 22 formed in the arm 21 is thus equipped with at least three subassemblies 23 each carrying two rollers 23A. The inner dimensions of each cradle 23B are adapted to partially cap with a minimum clearance, the roller 20. The rollers 23A are mounted on each cradle 23B so as to come into permanent contact with the roller 20, while allowing the free rotation of the roller 20 and rollers 23A resting on the roll 20.

This is maintained in each cradle 23B located in the groove 22 by the ends 200, 201 of the roller 20. An end 200 is connected to a rotary drive member, for example an electric motor M or hydraulic. The other end 201 is provided with a housing 202 in which engages a relief or rod 203 attached to one end of the arm 21. The dimensions of the housing 202 and the rod 203 are adapted to ensure the free rotation of the roll 20, which makes it possible, when the roll 20 is in rotation and put under stress, to preserve as much as possible its straightness.

When the roller 20 is resting on the rollers 23A and in place in the groove 22, part of its circumference, ie about 20%, lies outside the groove 22, thus outside the arm 21. This part of the roll forms the active area of it, suitable for bending a sheet.

The assembly, formed by the roller 20 and the arm 21, is disposed in the upper part of the machine 1, between the free ends of the uprights 3 and 4 of the main body 2. At its end 200, the roller 20 is connected to the motor M driving in rotation through an orifice in the heel 21A of the arm 21.

The arm 21 is fixed to the main body, for example by bolting one of its ends. The other end of the sleeve 21 is provided with a frustoconical mandrel 27. This mandrel is housed, when the roller 20 is rotating, in a movable arm 28. A pivoting movement of the arm 28 about an axis 28A fixed on the body 2, makes it possible to disengage the mandrel 27 and to release the end of the arm 21. This movement is represented by the arrow F ₃ at the figure 2 .

The assembly formed of the roller 20 and the arm 21 is fixedly positioned above the two support rollers 19. These are adjusted in height, so that the space between the rollers 20 and 19 corresponds globally to the thickness of the sheet to be bent.

The adjustment of this space is achieved by the vertical displacement of the cross member 9 under the action of the displacement of the wedges 8 in the notches 7.

One side of the machine, in the upper part, is equipped with several parallel tubes 29, arranged in a direction generally perpendicular to the axis A. These tubes 29 are interconnected by cross members 30 and thus form a plane, or a table 31, feeding machine. The dimensions of this feed table are adapted to the dimensions of the sheets 32. to bend.

The bars 29 are also provided with not shown, adjustable cleats, for maintaining a sheet 32 on the feed plane 31 so that the longitudinal axis of the plate 32 is substantially parallel to the axis A.

Advantageously, the bars forming the feed plane 31 are fixed on the crosspiece 9 equipped with support rollers 19. In this way, the height adjustment of the space between the bending roller 20 and the support rollers 19 as a function of the thickness of the sheet is accompanied by a concomitant movement of the feed plane 31 In this way a sheet 32 presented on the feed plane 31 is always, by one of its edges, facing the space provided between the roll 20 and at least one of the rollers 19.

When a sheet 32 is positioned on the table 31 with a roll 19 in contact with the sheet 32 and the roll 20 is rotated, the sheet 32 is driven between the roll 20 and one of the rollers 19. the sheet 32 between the rollers causes the bending of the sheet, that is to say gives it a curvature corresponding generally to the radius of a circle passing between the three rollers 19 and 20. The bending is carried out over the entire length of the sheet and over its entire width. Thus at the end of bending, the sheet 32 is rolled on itself, all at once, around the arm 21. It is then sufficient to move, according to the arrow F ₃ , the pivoting arm 28 to disengage the arm 21 and slide towards the outside of the machine 1 the tube T thus formed.

It is possible to evacuate the tube T automatically. In this case, the tube T is brought to a welding station which ensures the welding of its two edges.

Advantageously, with such a configuration, for stainless steel sheets 32 having a thickness of 0.4 to 0.6 mm, tubes T 60 mm in diameter and 1 meter long or 75 mm in length are produced. diameter for 1.20 m long.

Indeed, during the bending of the sheet metal the forces experienced by the rollers 19 and 20 to reach the final tube, given their respective ratio diameter / length and the thickness of the sheet, would tend to cause bending of the rollers 19 and 20. These arrows are compensated by the great inertia of the arm 21 and by the support of the rollers 23A on the roll 20 and the support of the ball bearings 16 on the rollers 19.

In particular, the bending roller 20 is held at both ends and the stress exerted by the sheet 32 is directed from bottom to top at the figure 4 . The roller 20 tends to take an arrow whose concavity is open towards The base of the machine 1. In a similar way, the support rollers 19 are made to take a reverse arrow, that is to say an arrow of generally equivalent radius, the concavity of which is directed towards the top of the machine 1. Arrows are controlled and compensated in an adjustable manner by the various means described above.

Indeed, the bending roller 20 is held by the rollers 23A supported by the arm 21 whose outer diameter and mass provide sufficient inertia so that it bends little under the forces incurred during the bending of the sheet 32. The roller 20 thus takes an arrow, called residual, corresponding to the arrow not compensated by the arm 21.

Similarly, the support rollers 19 are supported by the ball bearings 16. With the adjusting device 17, a free support of the bearings 16 is obtained on the rollers 19. This support is distributed locally over the length of the rollers 19 This support makes it possible to give the rollers 19 an inverse arrow, corresponding to the residual arrow of the roll 20, so as to keep the space between the rollers 19 and 20 constant throughout their respective lengths.

This maintenance of a constant space, adjustable between the rollers 19 and 20, makes it possible to obtain cylindrical tubes T with a rectilinear generatrix, whatever the sheet 32 used.

Depending on the length of the rollers 19 and 20 used and the thickness of the sheet 32, so the stress it exerts, it is easy to calculate the setting and the number of compensation means 11 and 23 needed to compensate. the arrows of the rollers 19 and 20.

By way of example, for rollers approximately 1.20 meters long and 20 mm in diameter, twelve compensation members 11 are regularly distributed under the rollers 19. In the sleeve 21 of the roll 20, twelve subassemblies 23B are also regularly distributed. Advantageously, the subsets 23B and the members 11 are arranged in staggered rows. In this way, during their rotation, the various rollers 19 and 20 are perfectly maintained over most of their respective lengths.

Moreover, the presence of an arm 21 partially covering the bending roller 20 makes it possible to reduce the risk of pinching, of driving an Member or a garment of a user by the machine 1. The arm 21 also participates in the safe use of the machine.

The arm 21 and the roller 20 are easily dismountable, for example, to be replaced by another sleeve / roller assembly of different diameter.

In other embodiments not shown, the adjustment of the arrow compensation means of the support rollers 19 is different from that described. It can be an electrical device, hydraulic or threaded rod.

Claims (10)

1. Machine of the roller type for bending metal sheets, said machine comprising, on the one hand, a roller (20) known as a "bending roller" which is driven in rotation and around which the metal sheet (32) is wound and, on the other hand, at least two supporting rollers (19) which are adapted to receive, resting on them, a metal sheet (32) which is in the process of being bent around the said bending roller (20), the said supporting rollers (19) being mounted so as to be free in rotation on a support (11) which can be adjusted in height, in such a way as to adapt the clearance between the said bending roller (20) and the said supporting rollers (19) to the thickness of the said metal sheet (32), the said bending roller (20) being associated with at least one set of means (21, 23) for compensating, at least partially, for its deflection, the said supporting rollers (19) being associated with at least one set (11) of means (12-16) for compensating for their deflection, the said set (11) being adjustable in accordance with the residual deflection of the said bending roller (20), characterised in that the said set of means (21, 23) for compensating for the deflection of the said bending roller (20) comprises an arm (21) provided with a recess (22) in which the said roller (20) is partially received, and also means (23A, 23B, 25, 26) for holding the said roller (20) in position in the said recess (22).
2. Machine according to claim 1, characterised in that the said recess is a groove (22), over the length of which are distributed at least three sets (23) of means (23A, 23B, 25, 26) for holding the said roller (20) in position with minimal deflection, when the said roller is in rotation.
3. Machine according to either of claims 1 or 2, characterised in that each of the sets (23) of holding means comprises two small rollers (23A) which rest on the said roller (20) in a direction which is perpendicular, overall, to a main axis (X₂₂) of the said recess (22).
4. Machine according to one of the preceding claims, characterised in that it comprises at least three sets (11) of means (12-16) for compensating for the deflection of the supporting rollers (19).
5. Machine according to claim 4, characterised in that each of the said sets (11) of compensating means comprises at least three juxtaposed ball bearings (16) fixed onto a support (15) which can be adjusted in height, for example by means of an inclined wedge (14).
6. Machine according to either of claims 4 or 5, characterised in that each of the said sets (11) of compensating means (12-16) can be adjusted in height individually by means of a micrometer screw (17A).
7. Machine according to one of claims 4 to 6, characterised in that all the sets (11) of compensating means are mounted in a sliding manner (10, 18) on a single base (9), which can itself be adjusted in height by means of at least two inclined wedges (8).
8. Machine according to one of the preceding claims, characterised in that the two sets (23) of means (23A, 23B, 25, 26) for holding the bending roller (20) in position are disposed substantially in a staggered arrangement in relation to the sets (11) of compensating means (12-16) for the supporting rollers (19).
9. Machine according to one of the preceding claims, characterised in that the said bending roller (20) is supported by an arm (21), with the aid of which it is mounted in a detachable manner on the said machine (1).
10. Line for producing tubes (T) or cylinders by bending metal sheets (32), said line comprising at least one machine (1) for bending metal sheets (32) which is made in accordance with one of the preceding claims.

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