FINISHING SECTION OF A MACHINE FOR PRODUCING SQUARE PIPES

Abstract

 Finishing section (10) of a machine for continuously producing square pipes, comprising at least one finishing station (11a, 11b, 11c, 11d) suitable for bringing further together the upper edges of a bent sheet strip (1) exiting a forming section, said at least one finishing station comprising a lower roller (20) with substantially horizontal axis, acting as a support for the square pipe being formed, two lateral rollers (21), placed at the sides of the square pipe being formed, mounted with the possibility of horizontal movement, i.e. parallel to the plane of the sheet strip (1), and two upper rollers (22), placed above the square pipe being formed, mounted with the possibility of vertical movement, i.e. orthogonal to the plane of the pipe, said horizontal and vertical movements being provided for adjusting the position of the lateral rollers (21) and of the upper rollers (22) according to the size of the pipe to be produced, wherein said lateral rollers (21) and said upper rollers (22) have variable inclination.

Description

[0001] The object of the present invention is a finishing section of a machine for continuously producing square pipes, i.e. with square or rectangular section.

[0002] A machine for the continuous forming of square pipes comprises a plurality of forming stations which progressively bend a strip of sheet metal, followed by a finishing section which comprises at least one station which brings further together, in view of final welding, the edges of the sheet metal strip bent by the forming stations, and at least one station for the final welding of the square pipe.

[0003] Machines for forming square pipes by means of continuous bending of strips of sheet metal are well known in the art and comprise, in series one with the other, a plurality of stations wherein the strip of sheet metal is progressively deformed by pairs of joined rollers, i.e. having grooves with complementary profiles.

[0004] These known machines have the disadvantage of making necessary the replacement of the pairs of rollers when the sizes of the pipe produced have to be changed, which entails machine down times of varying length which reduce the productivity of the line.

[0005] The need for maximum production flexibility linked to the reduction in production batches has led to the need for machines for production of the pipe with very short size change times.

[0006] These machines have some special features which distinguish them from others: in particular they do not need a tool change in the change from production of one size to another in the production range of the same machine.

[0007] Such a machine, defined as machine with variable linear geometry, is described for example in the European patent application EP 2279807, in the name of the same Applicant OLIMPIA 80 S.R.L., and provides a variable number of so-called "pipe forming" steps wherein the originally flat sheet metal is deformed, creating the lower and upper edges of a square or rectangular profile by means of adjustable rollers, and therefore adaptable to several sizes of pipes to be produced, which press on the sheet metal both from the outside and from the inside of the profile of the pipe being formed until the latter is sufficiently open. The pipe forming section is followed by a "pipe finishing" section wherein, it no longer being possible to act with rollers inside the profile of the pipe, rollers are provided which act from the outside to confer the final profile of the pipe before welding.

[0008] According to the aforementioned European patent the finishing section comprises a plurality of stations, each of which comprises a lower roller placed under the square pipe being formed, a pair of rollers with vertical axis, adjustable horizontally, placed at the sides of the square pipe being formed and a pair of rollers with horizontal axes, distanced longitudinally and adjustable vertically, placed above the square pipe being formed.

[0009] The lateral rollers with vertical axes are conical rollers in order to adapt to the lateral profile of the square pipe being formed and are placed in line with the lower roller.

[0010] The upper rollers are instead biconical rollers, again in order to adapt to the upper profile of the square pipe being formed and, as mentioned, are staggered longitudinally in order not to interfere with the lateral conical rollers.

[0011] The Applicant has noted that this arrangement of the rollers in the stations of the finishing section created problems which the present invention aims to solve.

[0012] In fact the lateral conical rollers have greater dimensions with respect to corresponding cylindrical rollers, which increases the transverse dimension of the machine.

[0013] The longitudinally staggered arrangement of the upper biconical rollers, imposed by the presence of the lateral conical rollers in line with the lower roller, generates a torque on the pipe being formed, determining an undulation of the same, with possible displacements and imperfect finishing.

[0014] The object of the invention is that of eliminating the disadvantages mentioned above. More particularly an object of the invention is that of providing a finishing section of a machine for the continuous production of square pipes, comprising at least one finishing station with an arrangement of the rollers such as to avoid any displacement or twisting or undulation of the square pipe being formed.

[0015] Another object of the invention is that of providing an arrangement and configuration of the rollers such as to make the corresponding finishing station compact.

[0016] These and other objects are achieved by the finishing section according to the invention which has the features of the annexed independent claim 1.

[0017] Advantageous embodiments of the invention are disclosed by the dependent claims. Substantially, each station of the finishing section according to the invention comprises:

• a lower roller which acts as support for the pipe being formed;
• two lateral rollers with adjustable inclination with the possibility of horizontal movement of opening/closure in order to cover the production range;
• two upper rollers with variable inclination with the possibility of vertical movement of rise/descent in order to cover the production range.

[0018] Conveniently the rollers are all cylindrical and of limited width, but they could also be slightly conical without departing from the scope of the invention.

[0019] The upper rollers are arranged in line with the lower roller, while the lateral rollers are staggered longitudinally with respect thereto.

[0020] The inclination of the lateral rollers can be adjusted manually by means of a trapezoidal screw, as also the horizontal movement of opening/closure of the lateral rollers is obtained by means of a trapezoidal screw moved by a gear motor and controlled by means of an encoder placed on the gear motor.

[0021] Likewise the inclination of the two upper rollers can be adjusted manually by means of a trapezoidal screw and the vertical movement of these rollers is obtained by means of a jack moved by a motor.

[0022] Further features of the invention will be made clearer by the following detailed description, referred to a purely non-limiting example thereof, illustrated in the accompanying drawings in which:

Figures 1A and 1B represent schematically the profile of a square pipe respectively through the steps of forming (Figure 1A) and through the steps of finishing (Figure 1B);

Figures 2A and 2B show schematically a side view and a view from above of the arrangement of the rollers in a finishing section according to the invention, made up of four successive stations;

Figure 2C is a perspective view of the finishing station of Figures 2A and 2B during work on a square pipe, wherein the arrows indicate the direction of forward movement of the pipe and the movements of the various rollers;

Figures 3A to 3H are section views taken respectively along the planes from A-A to H-H of Figure 2A;

Figures 4A, 4B and 4C are respectively a perspective view, a view from above and a side view in a finishing section with four stations, according to the invention;

Figures 5A and 5B are respectively a perspective view and a front view of the assembly carrying the lateral rollers of a finishing section according to the invention;

Figures 6A and 6B are respectively a perspective view and a front view of the assembly carrying the lower rollers and the upper rollers of a finishing section according to the invention.

The annexed Figures 1A and 1B show schematically the profile of a strip of sheet metal, denoted by reference numeral 1, respectively after the passage through a forming section and a finishing section of a machine for the continuous production of square pipes. Here below reference numeral 1 will also denote the square pipe being formed or formed.

[0023] The invention is aimed specifically at the finishing section which will be described here below with reference to Figures 2 to 6, while the forming station, to be considered in itself known, will not be described further.

[0024] The finishing section, denoted overall by reference numeral 10, is shown schematically in Figures 2 and 3, and comprises four finishing stations 11 a, 11b, 11c and 11d consecutive in the direction of forward movement of the sheet metal, i.e. the pipe being formed, from right to left in the example shown.

[0025] Obviously the finishing stations 11 can be in a number different from that illustrated, and in theory even only one can be provided.

[0026] Each finishing station comprises a fixed lower roller 20 with strictly cylindrical or slightly convex profile in order to avoid a convexity of the lower face of the pipe being formed, two lateral rollers 21 with variable inclination and with the possibility of horizontal movement of opening/closure in order to adapt to the range of pipes to be produced, and two upper rollers 22, also with variable inclination and with the possibility of vertical movement of rise/descent in order to adapt to the dimensions of the pipes to be produced.

[0027] The movements of the pairs of lateral rollers 21 and upper rollers 22 will be described here below with reference respectively to Figures 5 and 6.

[0028] As can be seen in Figures 2A-2C, the two upper rollers 22 are placed in line, i.e. on the vertical line of the lower roller 20, while the lateral rollers 21 are placed in a longitudinally staggered position with respect to the lower roller 20 and to the upper rollers 22, in particular they are placed upstream of these rollers in the direction of forward movement of the square pipe being formed 1.

[0029] As can be seen in Figures 2A-2C, and even better in Figures 3A-3H, the lateral rollers 21 and the upper rollers 22 have a different inclination according to the position of the corresponding station 11 in the finishing section 10.

[0030] More particularly Figures 3 A to 3H show how, moving from the first station 11a to the last station 11d, the angle of inclination α shown in the drawings, which corresponds to the inclination of the axis of the lateral rollers with respect to the vertical line, decreases from 20° to 6° in the example given, while the angle of inclination of the axis of the upper rollers 22 with respect to the horizontal line decreases from 23.5° to 4.5° in the example given.

[0031] Both the rollers 21 and the rollers 22 are cylindrical rollers, which makes the machine compact, above all in the transverse direction.

[0032] Figures 4A, 4B and 4C are overall views, respectively perspective, from above and side of a finishing section with four stations, according to the invention.

[0033] Figures 5 and 6 show the assemblies carrying respectively the lateral rollers 21 and the upper rollers 22 with the lower roller 20, illustrating the mechanisms which allow the movements of these rollers, which have been set to be arranged in the first finishing station 11a.

[0034] More particularly Figures 5A and 5B are respectively a perspective view and a front view of an assembly 11a' carrying the lateral rollers 21.

[0035] As can be seen from these drawings, the rollers 21 are mounted rotating on respective supports 30 with circular profile, so as to be able to slide in respective circular guides 31, so as to allow a rotation of the rollers around centres of rotation C1, C2 corresponding to the lower edges of the profile of the pipe 1 being formed, against which the lower edges of the rollers 21 are arranged.

[0036] In the example given the regulation of the inclination of the lateral rollers 21, i.e. their calibration as a function of the position which the corresponding station occupies in the finishing section, is performed manually by means of a trapezoidal screw whereof in Figures 5A and 5B the hexagonal head 32 is visible.

[0037] Naturally this regulation can be performed with any other type of actuator, for example of the hydraulic or electric type.

[0038] Figure 5 also shows locking screws 33 inserted in corresponding slots 34 to firmly block the supports 30 of the rollers 21, in the calibration position, with respect to the respective guides 31.

[0039] On the guides 31 a graduated scale 35 is also provided where it is possible to read with precision the angle of inclination of the rollers 21.

[0040] The circular guides 31 carrying the lateral rollers 21 are mounted on respective slides 36 sliding on respective guide blocks 37 attached to the plinth 40 of the finishing section.

[0041] The movement of the slides 36, which determines the opening/closure of the lateral rollers 21 in order to adapt them to the dimension of the square pipe to be formed is obtained, in the example shown, by means of a pair of trapezoidal screws 38 actuated by gear motor 39.

[0042] Referring to Figures 6A and 6B a description is now given of the setting of the upper rollers 22.

[0043] These rollers, like the lateral rollers 21, are carried by the respective supports 50 with circular profile, sliding in respective circular guides 51, so as to rotate around a centre of rotation corresponding to the intersection point of the extensions of the upper edges of the pipe 1 being formed, in order to be able to perform the calibration of these rollers on the basis of the position of the corresponding station in the finishing section.

[0044] This movement of the rollers 22, in the example given, is performed by means of respective trapezoidal screws 52, but it is clear that it can take place by means of any other type of actuator.

[0045] On the circular guides 51 graduated scales 55 are provided for a precise reading of the angle of inclination of the corresponding upper roller 22.

[0046] The circular guides 51 are mounted on vertical slides 56 sliding on uprights 57 attached to the plinth 40.

[0047] The slides 56 are joined above by a crosspiece 58 actuated to move vertically up and down in order to adapt the rollers 22 to the dimension of the square pipes to be produced, by means of a jack 59 moved by a motor 60.

[0048] In Figures 6A and 6B the lower roller 20 is shown with convex profile in order to avoid the possible convexity of the lower face of the square pipe 1, which could occur during the bending of its side walls, as mentioned previously.

[0049] However it is clear that the profile of the lower roller 20 can be perfectly cylindrical. The lower roller 20 is mounted on a support 70 with the possibility of a slight adjustment vertically, should the need arise.

[0050] All the rollers 20, 21, 22 of each finishing station are normally mounted idle around the relevant axes.

[0051] Naturally the invention is not limited to the particular embodiment previously described and illustrated in the accompanying drawings, but numerous detailed changes may be made thereto, within the reach of the person skilled in the art, without thereby departing from the scope of the invention itself as defined by the appended claims.

Claims

1. Finishing section (10) of a machine for continuously producing square pipes, adapted to be placed downstream of a forming section suitable for progressively bending a sheet strip (1), and upstream of a section for welding the formed square pipe, said finishing section (10) comprising at least one finishing station (11a, 11b, 11c, 11d) suitable for bringing further together the upper edges of the bent sheet strip exiting said forming section, said at least one finishing station comprising a lower roller (20) having a substantially horizontal axis, acting as a support for the square pipe being formed, two lateral rollers (21), placed at the sides of the square pipe being formed, mounted with the possibility of horizontal movement, i.e. parallel to the plane of the sheet strip (1), and two upper rollers (22), placed above the square pipe being formed, mounted with the possibility of vertical movement, i.e. orthogonal to the plane of the sheet strip (1), said horizontal and vertical movements being provided for adjusting the position of the lateral rollers (21) and of the upper rollers (22) according to the size of the pipe to be produced, characterised in that said lateral rollers (21) and said upper rollers (22) have adjustable inclination.

2. Finishing section according to claim 1, characterised in that said upper rollers (22) with adjustable inclination of said at least one finishing station (11) are aligned with, i.e. on the vertical line of, said lower roller (20), while said lateral rollers (21) are longitudinally staggered, in the direction of forward movement of the square pipe being formed, with respect to said rollers (20, 22).

3. Finishing section according to claim 2, characterised in that said lateral rollers (21) are placed upstream of said upper rollers (22).

4. Finishing section according to any one of the preceding claims, characterised in that said lateral rollers (21).are mounted on respective supports (30) sliding on corresponding circular guides (31), such as to be able to rotate around rotation centres (C1, C2) corresponding to the lower edges of the profile of the square pipe (1) being formed, at which the lower edges of the rollers (21) are placed.

5. Finishing section according to claim 4, wherein said lateral rollers (21) with relative supports (30) and circular guides (31) are mounted on respective slides (36) sliding horizontally and symmetrically on guide blocks (37) attached to a plinth (40) of the finishing section.

6. Finishing section according to any one of the preceding claims, characterised in that said upper rollers (22).are mounted on respective supports (50) sliding in respective circular guides (51), such as to be able to rotate around a rotation centre (C) corresponding to the intersection point of the extensions of the upper edges of the profile of the square pipe (1) being formed.

7. Finishing section according to claim 6, characterised in that said upper rollers (22) with the relative supports (50) and circular guides (51) are mounted on respective slides (56) sliding vertically on uprights (57) attached to the plinth of the finishing section.

8. Finishing section according to claim 7, wherein said vertical slides (56) are joined above by a crosspiece (58) actuated by a jack (59) by means of a motor (60).

9. Finishing section according to at least one of claims 4 to 7, wherein said movements for adjusting the inclination of said lateral rollers (21) and of said upper rollers (22) are performed by means of trapezoidal screws, and also the horizontal movement of the lateral rollers (21) is obtained by means of trapezoidal screws.

10. Machine for continuously forming square pipes comprising, in series one with the other, a forming section suitable for progressively bending a sheet strip (1), a finishing section (10) suitable for bringing further together the upper edges of the bent sheet strip and a section for welding the formed square pipe, characterised in that said finishing section (10) comprises at least one finishing station (11 a, 11b, 11c, 11d) according to any one of the preceding claims.

Drawing