IT201800009727A1 - Four-roller calender and its method of use - Google Patents

Description

Four-roller calender and its method of use

Technical sector

The present invention refers to a four-roller calender for bending metal sheets, profiles and the like.

The present invention also relates to a method of using the aforementioned calender for bending metal sheets, profiles and the like.

Note Art

In the industrial production of metal products, the use of four-roller calenders used to bend metal sheets into cylindrical, conical or oblong shapes is known.

For example, document US2018133772 A1 describes a calender comprising a fixed upper roller, a vertically movable lower roller and two side rollers, also movable. The use of this calender for the bending of a sheet involves a phase, called invitation, in which one end of the sheet is clamped between the upper roller and the lower roller and in which a side roller, the one on the side where it was once the sheet is inserted, it is raised, approaching the upper roller, so as to bend a portion of the sheet close to its end.

The Applicant has noted that four-roller calenders such as the one described in the aforementioned document have the problem of not being able to bend the ends of the sheets in an optimal way since, following the bending step, the sheet has an excessively long straight section adjacent to it. at the end of the sheet. In particular, the Applicant has observed that the aforesaid straight section is equal to at least twice the thickness of the sheet to be bent.

The object of the present invention is to overcome the problems and limitations of the known art by providing a calender with four rollers which allows to bend metal sheets and the like in an optimal way, reducing the length of the straight sections adjacent to the ends of the sheet.

A further object of the present invention is to provide a versatile four-roller calender, capable of assuming different configurations according to requirements.

These and other purposes are achieved with the four-roller calender as claimed in the attached claims.

Description of the Invention

The calender according to the present invention comprises an upper roller, a lower roller, a rear side roller, a front side roller and a support frame on which the aforesaid upper roller, lower roller, rear side roller and front side roller are mounted.

At least one of the upper roller and the lower roller is a motorized roller, that is a roller associated with a motor in order to be made to rotate around its own longitudinal axis. Preferably, the upper and lower rollers and the front and rear side rollers are all motorized.

The upper roller is mounted vertically movable, so as to be able to translate, moving away from or approaching the lower roller, and the lower roller is mounted horizontally movable, so as to be able to translate with respect to the upper roller. In particular, the lower roller is configured to be able to be moved at least anteriorly or posteriorly with respect to a vertical rectilinear translation direction of the upper roller.

The rear and front side rollers are movably mounted on the frame so that they can move away from or approaching the upper roll. In particular, the side rollers can translate along straight or curved trajectories.

The translational motions of said upper roller, lower roller, rear side roller and front side roller are imparted by respective hydraulic actuators and are preferably guided by means of suitable straight or curved guides.

In accordance with the present invention, a method of using the calender provides for the steps of:

- insert the sheet to be bent between the lower roller and the upper roller of the calender;

- make the lower roller move horizontally front / rear with respect to a position in which its longitudinal axis is aligned vertically with respect to the longitudinal axis of the upper roller;

- lower the upper roller vertically, so as to bend a portion of the sheet while the sheet rests on the rear / front side roller, respectively.

The aforementioned phases of horizontal translation of the lower roller front / rear and vertical lowering of the upper roller are performed after the phase of:

- vertically lower the upper roller in order to clamp the sheet between the upper roller and the lower roller which is with its longitudinal axis aligned vertically with respect to the longitudinal axis of the upper roller.

Advantageously, the aforementioned stages of horizontal translation of the lower roller front / rear and vertical lowering of the upper roller are performed when the front / rear end, respectively, of the sheet is clamped between the upper roller and the lower roller. This allows you to bend the ends of the sheet by limiting the length of the sections adjacent to the ends that cannot be bent and therefore remain straight. In particular, the Applicant has observed that with the calender and the method of use according to the present invention it is possible to obtain rectilinear portions adjacent to the ends of length up to about one and a half times the thickness of the sheet to be bent.

In accordance with another method of using the calender, the lower roller is maintained with its longitudinal axis always aligned vertically with respect to the longitudinal axis of the upper roller.

In accordance with a further method of using the calender, it is envisaged that the upper roller is always kept raised and that, to bend the sheet, only three rollers are used, i.e. the upper roller (motorized) and the two side rollers (motorized or idle). ). This configuration is, for example, advantageous for obtaining bends with a large diameter.

Furthermore, by acting on the reciprocal inclination of the rollers, the calender can be used to perform truncated conical bends.

The calender object of the invention is therefore highly versatile, as it is able to assume different configurations according to needs.

Brief Description of the Figures

These and other characteristics and advantages of the present invention will become more evident from the following description of preferred embodiments given by way of non-limiting example with the aid of the attached figures, in which elements indicated with the same or a similar numerical reference indicate elements that they have the same or similar functionality and construction and in which: - Figure 1 is a schematic front view of a calender according to the invention;

- Figures 2a-2o are schematic views of the phases of a first bending method using the calender according to the invention;

- Figures 3a-3h are schematic views of the phases of a second bending method using the calender according to the invention;

- Figures 4a-4e are schematic views of the steps of a third bending method using the calender according to the invention.

Description of some Preferred Forms of Realization of the Invention

With reference to Figure 1, a preferred embodiment of a calender 10 according to the invention is described below, for bending metal sheets, profiles and the like (in the following, to simplify, reference will be made to a sheet 30) .

The calender 10 comprises a support frame 11 on which an upper roller 12, a lower roller 13 and a first 14 and a second side roller 15 are mounted movably, each independently of the other.

The upper roller 12 is a motorized roller, for example driven by a hydraulic motor (not shown) preferably associated with one of the ends of the roller, for example by means of a suitable gearmotor, in order to transmit to the upper roller 12 a rotary motion around its own. longitudinal axis X.

In accordance with the present invention, the upper roller 12 is vertically movable, i.e. it can be made to translate along a vertical rectilinear direction, so that it can be moved away from or approached the lower roller 13. The translational movement of the upper roller 12 is preferably given , by means of two hydraulic actuators 16 (of which only one is shown), each associated with a respective end of the roller 12. Furthermore, preferably, the translational motion is guided by vertical rectilinear guides 21.

The lower roller 13 is also preferably a motorized roller, associated, in a similar way to what has been described above for the upper roller 12, to a respective motor, for example by means of a gearmotor, in order to transmit to the lower roller 13 a rotational motion around its own longitudinal axis Y.

In accordance with the present invention, the lower roller 13 is horizontally movable, that is, it can be made to translate along a horizontal rectilinear direction, so as to be able to be moved forward or backward with respect to the vertical rectilinear translation direction of the upper roller 12. The translational movement of the lower roller 13 is preferably imparted by means of two pairs of hydraulic actuators 17, 18 (of which only one is shown), each associated with a respective end of the roller 13, and is preferably guided by horizontal rectilinear guides 22.

The first side roller 14 is arranged at the rear with respect to the lower roller 13, that is, by convention, on the insertion side of the sheet to be bent into the calender. The second side roller is arranged in front of the lower roller, that is, on the side opposite to the side where the sheet to be bent 30 is inserted into the calender.

Both side rollers 14, 15 are preferably motorized rollers, each associated, in a similar way to what was previously described for the upper roller 12, to a respective motor, for example by means of a gearmotor, in order to transmit to each side roller 14 , 15 a rotary motion about the respective longitudinal axis Z, W.

In accordance with the present embodiment of the calender 10, the side rollers 14, 15 are movable along respective rectilinear, oblique directions, directed towards the upper roll 12, so as to be able to be moved away from or approached to the upper roll 12. The movement translation of each side roller 14, 15 is preferably imparted by means of two respective hydraulic actuators 19, 20 (of which only one per roller is shown) associated with the ends of the respective side roller 14, 15. Furthermore, the translational movement of each side roller 14, 15 is preferably guided by respective oblique rectilinear guides 23, 24.

In accordance with further embodiments of the invention (not shown), the side rollers translate along curved trajectories. For example, the rollers can translate guided by planetary guides or be supported by respective oscillating arms pivoted to lateral pins.

Furthermore, in accordance with further embodiments, the lower roller and / or the side rollers can be idle rather than motorized.

The rollers 12, 13, 14, 15 of the calender 10 are preferably supported by bearings (not shown) to allow their rotary motion.

The calender 10 according to the invention is preferably managed by numerical control systems and is equipped with electronic control of the parallelism of the side rollers 14, 15 and the upper roll 12.

With reference to Figures 2a-2o, a method of using the calender 10 as described above for bending a metal sheet 30 is described below.

In a first step (Figure 2a), the rear side roller 14 is lowered and the upper roller 12 is raised so as to allow the sheet metal to be bent 30 to be inserted between the lower roller 13 and the upper roller 12, from the insertion side (by convention, the back side). The front side roller 15 is located at the insertion height of the sheet 30 and is used as an abutment for the front end 31 of the sheet 30, allowing it to be aligned.

Subsequently, the upper roller 12 is lowered so as to clamp the sheet 30 between the upper roller 12 and the lower roller 13, which is with its longitudinal axis Y aligned vertically with respect to the longitudinal axis X of the upper roller 12 (Figure 2b) . The sheet 30 is advantageously kept clamped during all the subsequent steps, thus avoiding possible slippage thereof and therefore keeping it aligned.

The upper 12 and lower 13 rollers are then made to rotate, so as to make the metal sheet 30 retract until its front end 31 is pinched between the upper 12 and lower 13 rollers, while the front side roller 15 is lowered ( Figure 2c).

The lower roller 13 is then made to move forward (Figure 2d) and the upper roller 12 is lowered (Figure 2e), so as to bend a portion 30a of the sheet 30 close to its front end 31 while the sheet 30 rests on the rear side roller 14. The aforesaid step of bending the portion 30a of the sheet 30 close to its front end 31 is called the bending (first opening).

In Figure 2e, as well as in all subsequent figures, the portion of curved sheet metal is depicted in gray.

After the first invitation, the rollers 12, 13, 14, 15 are made to rotate so as to advance the sheet metal 30 until its rear end 32 is clamped between the upper rollers 12 and lower 13 (Figure 2f).

The lower roller 13 is then made to move forward (Figure 2g) and the upper roller 12 is lowered (Figure 2h), so as to bend a portion 30b of the sheet 30 close to its rear end 32 while the sheet 30 rests on the front side roller 15. The aforesaid step of bending the portion 30b of the sheet 30 close to its rear end 32 is called the lead (second lead).

After the second lead-in, the lower roller 13 is made to move forward, so as to bring it back with its longitudinal axis Y aligned vertically with respect to the longitudinal axis X of the upper roller 12, and the front side roller 15 is raised, bending a portion 30c of sheet metal 30 between the upper 12 and lower 13 rollers and the front side roller 15 (Figure 2i).

The upper 12 and lower 13 rollers are then made to rotate so as to make the sheet 30 retract until the portion 30c of sheet 30 bent in the previous step is posterior to the upper 12 and lower 13 rollers (Figure 2l). In this phase, preferably, the front side roller supports the sheet, without bending it further.

The front side roller 15 is then lowered while the rear side roller 14 is raised, until it comes into contact with the sheet metal 30 (Figure 2m).

Continuing the rotation of the upper 12 and lower 13 rollers, causing the sheet metal 30 to move backward, it continues to be curved (Figure 2n) until it obtains a cylindrical shape, called ferrule 33 (Figure 2o).

As an alternative to the sequence of steps illustrated above, it is possible to proceed with the bending of central portions of the sheet 30 after the first bending and carrying out the second bending as the final step.

The calender 10 according to the present invention can also be used by keeping the lower roller 13 with its longitudinal axis Y always aligned vertically with respect to the longitudinal axis X of the upper roller 12.

A method of using the calender 10 in the aforementioned configuration with non-translating lower roller 13 is described below with reference to Figures 3a-3h.

In a first step (Figure 3a), the rear side roller 14 is lowered and the upper roller 12 is raised so as to allow the sheet metal to be bent 30 to be inserted between the lower roller 13 and the upper roller 12, from the insertion side (by convention, the back side). The rear side roller 14 is located at the insertion height of the sheet 30 and is used as an abutment for the front end 31 of the sheet 30, allowing it to be aligned.

Subsequently, the upper roller 12 is lowered so as to clamp the sheet 30 between the upper roller 12 and the lower roller 13 (Figure 3b). The sheet 30 is advantageously kept clamped during all the subsequent steps, thus avoiding possible slippage thereof and therefore keeping it aligned.

The upper 12 and lower 13 rollers are then made to rotate, so as to make the metal sheet 30 retract until its front end 31 is clamped between the upper 12 and lower 13 rollers, while the front side roller 15 is lowered ( Figure 3c).

The rear side roller 14 is then raised, bending a portion of sheet metal 30d comprised between the upper 12 and lower 13 rollers and the rear side roller 14 (Figure 3d). The aforesaid step of bending the sheet 30 is called the first bite.

The upper 12 and lower 13 rollers are then made to rotate so as to advance the sheet 30 until the portion 30d of sheet 30 bent in the previous step is located in front of the upper 12 and lower rollers 13 (Figure 3e). In this phase, preferably, the front side roller supports the sheet, without bending it further.

The rear side roller 14 is then lowered while the front side roller 15 is raised, until it comes into contact with the metal sheet 30 (Figure 3f).

Continuing the rotation of the upper 12 and lower 13 rollers, making the sheet 30 advance, it continues to be curved (Figure 3g) until obtaining a cylindrical shape, called ferrule 33 (Figure 3h).

The calender 10 according to the present invention can also be used keeping the upper roller 12 always raised, using only three rollers to bend the sheet, that is the upper roller 12 and the two side rollers 14, 15.

A method of using the calender 10 in the aforementioned three-roller configuration is described below, with reference to Figures 4a-4e.

In a first step (Figure 4a), the rear side roller 14 is lowered so as to allow the sheet metal to be bent 30 to be inserted horizontally between the upper roller 12 and the rear side roller 14, from the insertion side (by convention, the rear side). The front side roller 15 is located at the insertion height of the sheet 30 and is used as an abutment for the front end 31 of the sheet 30, allowing it to be aligned.

Subsequently, the rollers 12, 14, 15 are made to rotate by advancing the sheet metal 30 and by bending a front portion 30e of the same, thus making the first indentation (Figure 4b).

After bringing the side rollers 14, 15 to the same height, the rollers 12, 14, 15 are rotated by bringing the rear end 32 of the sheet 30 between the rear side roller 14 and the upper roller 12.

The rear side roller 14 is then raised and the rollers 12, 14, 15 are made to rotate by retracting the sheet 30 and bending a rear portion 30f thereof, thus making the second opening (Figure 4c).

The front side roller 15 is then raised and the rollers 12, 14, 15 are made to rotate by moving back the sheet 30 and bending a central portion 30g of the same (Figure 4d) until a cylindrical shape is obtained, called ferrule 33 (Figure 4e) .

As will be clear to those skilled in the art, the methods of operation described above are given for illustrative purposes only and do not represent the only possible methods.

For example, when the calender 10 operates in the configuration with a non-translating lower roller 13, after the first bending it is possible to advance the sheet 30 without bending it and to bend a portion of the sheet close to its rear end 32 (i.e. perform the second bending), and only subsequently bend the central portion of the sheet 30.

Furthermore, by acting on the reciprocal inclination of the rollers, the calender 10 can be used to perform truncated conical bends of the sheet.

Claims (10)

Claims 1. Calender (10) comprising: - an upper roller (12), a lower roller (13), a rear side roller (14) and a front side roller (15), - a support frame (11) on which said upper roller (12), lower roller (13), rear side roller (14) and front side roller (15) are mounted, in which at least one of the upper roller (12) and the lower roller (13) is a motorized roller and in which the rear (14) and front (15) side rollers are mounted movably on the frame (11) so as to be able to translate moving away from / approaching the upper roller (12), characterized by the fact that the upper roller (12) is mounted vertically movable, so as to be able to translate, moving away from or approaching the lower roller (13), and the lower roller (13) is mounted horizontally movable, so as to be able to translate with respect to the upper roller (12) ). Calender (10) according to claim 1, wherein the lower roller (13) mounted horizontally movable is configured to be able to be moved forward and / or rearward with respect to a vertical rectilinear translation direction of the upper roller (12). Calender (10) according to claim 1 or 2, in which the front (15) and rear (14) side rollers are motorized. Calender (10) according to any one of the preceding claims, in which the side rollers (14, 15) translate along straight or curved trajectories. Calender (10) according to any one of the preceding claims, managed by numerical control systems. 6. Calender (10) according to any one of the preceding claims, in which the translational motions of said upper roller (12), lower roller (13), rear side roller (14) and front side roller (15) are imparted by means of respective actuators plumbers (16, 17, 18, 19, 20). 7. Calender (10) according to any one of the preceding claims, further comprising guides (21, 22, 23, 24) suitable for guiding the translational motions of said upper roller (12), lower roller (13), rear side roller (14) ) and front side roller (15), respectively. Method of using a calender (10) according to any one of claims 1 to 7, comprising the steps of: - insert the sheet to be bent (30) between the lower roller (13) and the upper roller (12); - translate the lower roller (13) horizontally front / rear with respect to a position in which the longitudinal axis (Y) of the lower roller (13) is aligned vertically with respect to the longitudinal axis (X) of the upper roller (12); - lower the upper roller (12) vertically, so as to bend a portion (30a, 30b) of the sheet (30) while the sheet (30) rests on the rear (14) / front (15) side roller, respectively. Method according to claim 8, in which said steps of horizontally translating the lower roller (13) front / rear and lowering the upper roller (12) vertically are performed after the step of: - vertically lower the upper roller (12) so as to clamp the sheet (30) between the upper roller (12) and the lower roller (13) which is with its longitudinal axis (Y) aligned vertically with respect to the longitudinal axis ( X) of the upper roller (12). Method according to claim 9, wherein said steps of horizontally translating the lower roller (13) front / rear and lowering the upper roller (12) vertically are performed when the front (31) / rear (32) end, respectively, some sheet metal (30) is clamped between the upper roller (12) and the lower roller (13).