Equipment for track cutting and calibration of tubes

Abstract

A device (14) for orbital cutting and calibration of tubes (T) is described, comprising: a rotor (18) having a central hole (20) through which the tube (T) to be cut can be moved along its longitudinal axis, the rotor (18) being drivable to rotate about a first rotation axis (x1) which, in use, coincides with the longitudinal axis of the tube (T) fed to the device (14); a cutting device (22, 24) comprising a first support (22) mounted so as to be radially movable on the rotor (18) and a cutting tool (24) carried by the first support (22); and a calibration device (34, 36) comprising a second support (34) mounted so as to be radially movable on the rotor (18) and a calibration tool (36) carried by the second support (34).

Description

Technical Field

[0001] The invention relates to an apparatus for orbital cutting of tubes and for aligning the tubes themselves after cutting. Background Art

[0002] The so-called orbital cutting process is known for cutting tubes having a circular cross section, such as tubes which are subjected to bending on a tube bending machine or tubes which are subjected to end deformation on a tube end forming machine.

[0003] Orbital cutting of circular cross-section tubes is an operation without chip removal, which is performed by operating a circular cutter, usually called a cutting roll, to make a number of revolutions around the tube, gradually scoring the tube to allow the tube segments to be separated from the starting rod or coil. The tube segments are thus separated from the rod or coil in one of the following known ways:

[0004] - through-cutting, according to which the cutting rollers gradually score the pipe completely through its thickness;

[0005] - scoring and breaking, whereby the cutting rollers gradually score the tube without penetrating the thickness of the tube, and the separation of the tube sections is carried out by the action of a tension force applied during or immediately after the advancement of the cutting rollers; and

[0006] Scoring and breaking, according to which cutting rollers gradually notch the tube without penetrating its thickness and separate the tube sections by flexing action.

[0007] In the attached figure Figure 1 An example of a known line for feeding and cutting tubes is shown, comprising a feeding unit 10 for feeding the tube T (possibly originating from a turned and straightened tube coil), a clamping unit 12 for clamping the tube T, a cutting unit 14 for orbital cutting of the tube T, and a breaking unit 16 for breaking the segments of the tube T after being cut by the cutting unit 14. The breaking unit 16 may also not be provided or used if the separation of the tube segments is carried out by the aforementioned through-cutting method.

[0008] In the attached figure Figure 2 and Figure 3 The cutting unit 14 is specifically shown in FIG. Figure 3 Shown on an enlarged scale Figure 2 Details of A.

[0009] Reference Figure 2 and Figure 3, the cutting unit 14 comprises a rotor 18 having a central hole 20, through which the tube T for cutting passes. The rotor 18 is equipped with a support 22 carrying a cutting roller 24. The rotor 18 is driven in rotation about a first rotation axis x1 coinciding with the longitudinal axis of the tube T, for example by a gear motor unit comprising an electric motor 26. The support 22 is movable in a radial direction (indicated by y) relative to the rotor 18. The cutting roller 24 is freely rotatable relative to the support 22 about a second rotation axis x2 parallel to the first rotation axis x1.

[0010] Referring to the attached drawings Figures 4 to 7 , by cutting units (such as Figure 2 and Figure 3 The cutting process of the tube T performed by the cutting unit shown in FIG. 1 is performed according to the following steps (for simplicity, a through-cutting technique for separating the tube segments from the tube stick fed by the feeding unit 10 is considered).

[0011] first( Figure 4 ), the tube T is moved axially (ie, in the direction of the longitudinal axis of the tube, which direction coincides with the axis of rotation x1 of the rotor 18 as described above) until the portion of the tube T to be cut is located at the cutting roller 24.

[0012] at this time( Figure 5 ), the cutting roller 24 is moved into contact with the surface of the tube T, causing the support body 22 to radially translate toward the longitudinal axis of the tube T, and the rotor 18 is driven to rotate around the first rotation axis x1, so that the cutting roller 24 performs a series of rotations around the tube T.

[0013] like Figure 6 As shown, during the rotational movement of the rotor 18, the support body 22 and the cutting rollers 24 carried by it are radially translated toward the longitudinal axis of the tube T, so that the cutting rollers 24 produce a gradually deepening circumferential groove C in the thickness of the tube until it causes the separation of the tube section (indicated by P).

[0014] Finally, if Figure 7 As shown, the rotation of the rotor 18 is interrupted and the cutting rollers 24 return to the radial starting position, away from the surface of the tube T.

[0015] The orbital cutting process suffers from the disadvantage that the thrust of the cutting rollers from the outside of the tube inwards produces a displacement of the material in the radial direction towards the inside of the tube, resulting in a reduction in the inner diameter of the tube. In addition to the reduction in the inner diameter of the tube due to the reduction in the outer diameter of the tube, the reduction in the inner diameter of the tube due to the formation of burrs must also be taken into account.

[0016] Reduction in the internal diameter of the tube is an undesirable effect of cutting because it may affect subsequent operations on the tube, particularly any bending of the tube using a core (reduction in the internal diameter of the tube in the area surrounding the cut requires the use of a core with a diameter smaller than the internal diameter of the tube, with the resulting risk of bending defects) and because it may affect the properties of the final product.

[0017] The extent to which the inner diameter of a tube is reduced as a result of orbital cutting is closely related to many factors, including the geometry of the tool (such as size, rake angle, sharpness - the latter however tends to decrease with use), the cutting parameters (such as penetration speed) and the mechanical and metallurgical characteristics of the tube being processed.

[0018] Because many factors are involved, it is not always possible to maintain the reduction in the inner diameter of the tube within acceptable limits during operation.

[0019] It is therefore known to perform, after orbital cutting, in a specific unit arranged downstream of the cutting unit, a calibration operation on the cut pipe section in order to bring the internal diameter of the pipe back to a nominal value. The calibration operation may for example comprise a trimming or deburring operation.

[0020] However, this solution is not optimal, since it increases the cost, size and complexity of the installation, since specific processing units need to be provided, since the tubes must be properly handled between the cutting unit and the calibration unit, and since the waste generated by the calibration operation needs to be properly disposed of. Moreover, the performance of this additional operation involves an increase in the cycle time, which is therefore detrimental to the productivity of the tube processing plant (for example bending).

[0021] It is also known to carry out the calibration operation according to the so-called "push" technique, i.e. using a special punch coaxially positioned relative to the tube and pushed a certain distance (for example a few millimeters) inside the tube, so as to achieve a calibrated enlargement of the internal diameter of the tube. Although some of the negative effects of calibration are overcome by means of squaring, push calibration has the disadvantage of causing the burr to move inside the tube, which may cause problems in subsequent processing steps of the tube or in the final use of the tube itself. Summary of the invention

[0022] The object of the present invention is therefore to provide an apparatus for orbital cutting of tubes and their calibration after cutting which does not suffer from the above-mentioned disadvantages of the prior art.

[0023] According to the invention, this and other objects are fully achieved by a device having the following characteristics.

[0024] Advantageous embodiments of the invention are defined in the following embodiments, the contents of which are to be understood as an integral part of the following description.

[0025] In brief, the invention is based on the idea of ​​creating an apparatus for cutting and calibrating tubes, comprising:

[0026] a rotor having a central aperture through which the tube to be cut is moved, the rotor being drivable to rotate about a first axis of rotation;

[0027] a cutting device comprising a first support body mounted to be radially movable on the rotor and a cutting tool carried by said first support body; and

[0028] a calibration device comprising a second support mounted to be radially movable on the rotor and a calibration tool carried by said second support;

[0029] The calibration tool can be moved radially outward to expand the inner diameter of the pipe section.

[0030] Due to the fact that the device comprises a cutting device and a calibration device mounted on the same rotor, the use of an additional processing unit downstream of the cutting unit to perform the calibration of the tube after cutting is avoided, thus avoiding all the aforementioned disadvantages associated with the presence of such an additional processing unit. Moreover, since the calibration tool is mounted on a support that is radially movable relative to the rotor (and therefore relative to the tube being processed), the calibration of the tube is carried out by radial movement of the tool relative to the tube, and not by axial movement (i.e. direct movement along the longitudinal axis of the tube) as occurs in push calibration, thus avoiding the disadvantage of moving the burr inside the tube typical of push calibration.

[0031] Preferably, the first support body and the second support body are distinct bodies and are both mounted on the rotor such that they are movable in the same radial direction.However, alternatively, a single support body may be provided that carries both the cutting tool and the calibration tool.

[0032] According to one embodiment, in order to drive the radial movement of the first and second supports (and thus the cutting tool and the calibration tool) relative to the rotor (and thus relative to the tube), the device comprises a single drive device paired with the first and second supports to control the radial movement of the supports symmetrically relative to the axis of rotation of the rotor (i.e. relative to the longitudinal axis of the tube). Alternatively, a first drive device and a second drive device may be provided, each drive device being paired with a respective support, so that the radial movement of the first and second supports can be driven independently of each other.

[0033] Preferably, the cutting tool is formed by a roller mounted on said first support so as to be freely rotatable about a second axis of rotation parallel to said first axis of rotation and which has a circumferential cutting edge.

[0034] As for the calibration tool, it may be configured to enlarge the tube by plastic deformation or alternatively by chip removal.In the second case, the calibration tool will be equipped with a cutting edge suitably shaped to machine the free end of the tube.

[0035] Another subject of the invention is a machine for processing tubes, such as a machine for straightening and cutting tubes from coils, comprising a device for cutting and calibrating tubes having the characteristics previously described.

[0036] According to one embodiment, the machine is configured to perform the following steps:

[0037] While the rotor is rotating, a pipe section is cut from the pipe by a cutting tool;

[0038] moving the pipe section axially away from the remainder of the pipe;

[0039] moving the calibration tool radially toward the longitudinal axis of the tube until it reaches a predetermined position within the radial dimension of the tube;

[0040] axially moving the pipe section toward a calibration tool;

[0041] As the rotor rotates, the calibration tool is moved radially outward to expand the inside diameter of the pipe section. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Other features and advantages of the present invention will become more apparent from the following detailed description, which is provided by way of non-limiting example only with reference to the accompanying drawings, in which:

[0043] Figure 1 is a perspective view showing a line for feeding and cutting tubes according to the prior art;

[0044] Figure 2 Yes Display Figure 1 A perspective view of the cutting unit of the feeding and cutting line;

[0045] Figure 3 Shown at an enlarged scale Figure 2 Details of A;

[0046] Figures 4 to 7 The use of Figure 2 and Figure 3 Some steps in the process of cutting the tube by the cutting unit;

[0047] Figure 8 is a perspective view of an apparatus for cutting tubes and aligning them after cutting according to an embodiment of the present invention;

[0048] Fig. 9 It is shown in detail Figure 8A perspective view of a cutting device and a calibration device of the apparatus in FIG. 1 ; and

[0049] Figures 10 to 16 The use of Figure 8 Some steps in the process of calibrating the device tube. DETAILED DESCRIPTION

[0050] First reference Figure 8 and Fig. 9 , where Figures 1 to 7 Parts and elements identical or corresponding to those in (the prior art) are given the same reference numerals, and a cutting and calibration device (hereinafter referred to as "device" for convenience) is collectively designated 14, which is suitable for successively performing the cutting of the tube T and the calibration of the tube section P thus cut so as to return the inner diameter of the tube section P to its initial value (nominal diameter).

[0051] The device 14 comprises a rotor 18 having a central hole 20, through which the tube T to be cut passes through a feed unit (not shown here, but of a type known per se, see for example Figure 1 The feed unit 10 in FIG. 1 is moved through the central hole 20 along its longitudinal axis. The rotor 18 is supported to rotate about a first rotation axis x1 that coincides with the longitudinal axis of the tube T. The device 14 further comprises a first drive device 26 (e.g., an electric gear motor) to drive the rotor 18 to rotate about the first rotation axis x1.

[0052] The rotor 18 is equipped with a support body 22 carrying a cutting tool 24. The cutting tool 24 is configured, for example, as a roller with a sharp circumferential edge. The cutting tool 24 is freely rotatable relative to the support body 22 about a second rotation axis x2 parallel to the first rotation axis x1.

[0053] The support body 22 is movable in the radial direction y relative to the rotor 18. In this respect, the support body 22 is, for example, rigidly connected to a slide 28 which is slidably mounted in a slot extending in the radial direction y of the rotor 18. A second drive device 32, for example an electric gear motor, is paired with the support body 22, or more precisely with the slide 28, to drive the translational movement of the slide 28 and therefore of the support body 22 in the radial direction y.

[0054] According to the invention, in addition to the cutting means formed by the cutting tool 24 and its support 22 , the device 14 also comprises a calibration device comprising a support 34 and a calibration tool 36 carried by the support 34 .

[0055] The support 34 is mounted radially movably on the rotor 18, preferably in the same radial direction y in which the support 22 carrying the cutting tool 24 is movable. Preferably, the support 34 is rigidly connected to a slide 38. The slide 38 is slidably mounted in a slot 40 of the rotor 18. The slot 40 extends in the radial direction y on the side opposite to the slot with respect to the axis of rotation x1 of the rotor 18.

[0056] The support 34, or more precisely the slide 38, is also paired with drive means to drive the translational movement of the slide 38 and therefore of the support 34 along the radial direction y. Preferably, the slide 38 is driven by the same drive means 32 that also drives the slide 28, so that the two slides 28 and 38 and the associated supports 22 and 34 move together with them exactly symmetrically relative to the axis of rotation x1 of the rotor 18, i.e. relative to the longitudinal axis of the tube T.

[0057] The cutting tool 24 is used in the same manner as explained above with reference to the prior art (see Figures 4 to 7 and related description) cutting tube T.

[0058] refer to Figures 10 to 16 A possible way of carrying out an operation of calibrating a newly cut pipe section using the device according to the invention will now be described, as the operation is used to restore the inner diameter of the pipe section at the cutting zone to the initial value (nominal diameter) in order to compensate for the effect of reducing the inner diameter of the pipe due to the cutting operation.

[0059] When the calibration tool 36 is in the general starting position ( Fig.10 ) and the newly cut pipe section P has been axially moved (if necessary, by a special breaking unit) away from the rest of the pipe stick T ( Fig.11 ) Afterwards, the tube T is retracted by a feed unit (not shown here) to emerge from the axial dimension of the cutting and calibration device ( Fig.12 ).

[0060] At this time, if Fig.13 As shown, the calibration tool 36 moves radially towards the longitudinal axis of the tube until it reaches a predetermined position. In the example shown, only one drive unit is provided for both the cutting device and the calibration device, so the cutting tool 24 also moves in the radial direction towards the longitudinal axis of the tube, but in the case of two independently moving tools, the cutting tool can of course remain stationary in the starting position, since it does not intervene during the calibration operation.

[0061] The pipe section P is then moved axially towards the calibration tool 36 until it reaches a position for operating the tool ( Fig.14 ).

[0062] At this point, the rotor 18 is caused to rotate (even though the rotor may have been kept rotating continuously in the previous steps described above, possibly at a speed different from the speed used during the actual calibration operation), while the calibration tool 36 is suitably moved outwardly in the radial direction to a predetermined position (or with a predetermined force) in order to produce the necessary enlargement of the inner diameter of the pipe section P ( Fig.15 ). As previously mentioned, the calibration tool 36 may be arranged to perform calibration by plastic deformation of the tube, as in the example shown here, or alternatively it may be arranged to perform calibration by chip removal.

[0063] Finally, if Fig.16 As shown, once the calibration operation is completed, the newly machined tube section is unloaded and the calibration tool 36 is moved radially outwardly beyond the radial dimensions of the tube T until it reaches the starting position.

[0064] As is evident from the description given above, with the device according to the invention, the calibration operation can be carried out immediately after the cutting of the tube, thus reducing the cycle time to a minimum. In fact, it is no longer necessary to transfer the newly cut tube section to another workstation dedicated to calibrating the tube. Moreover, the integration of the calibration tool and the cutting tool in the same device greatly simplifies the installation and reduces the manufacturing costs and the space requirements.

[0065] Naturally, without altering the principle of the invention and without departing from the scope of the invention as defined in the appended claims, the embodiments and details of implementation may vary widely with respect to those described and illustrated purely by way of non-limiting example.

Claims

1. A device for track cutting and calibration of a tube (T), comprising: a rotor (18) having a central hole (20) through which the tube (T) to be cut can be moved along its longitudinal axis, the rotor (18) being drivable in rotation about a first axis of rotation (x1) which, in use, coincides with the longitudinal axis of the tube (T) supplied to the apparatus (14); a cutting device (22, 24) comprising a first support (22) mounted on the rotor (18) so as to be radially movable and a cutting tool (24) carried by the first support (22); as well as a calibration device (34, 36) comprising a second support (34) mounted on the rotor (18) so as to be radially movable thereon, and a calibration tool (36) carried by the second support (34); wherein the calibration tool (36) is capable of moving outward in a radial direction to achieve an expansion of the inner diameter of the pipe section (P) of the pipe (T), wherein the first support body (22) and the second support body (34) are independent of each other and are both mounted on the rotor (18) so as to be able to move along the same radial direction (y), wherein the device also includes a single drive device (32) paired with both the first support body (22) and the second support body (34) so ​​as to drive the first support body (22) and the second support body (34) to move along the radial direction (y) in a manner symmetrical with respect to the first rotation axis (x1).

2. The device according to claim 1, wherein: The cutting tool (24) is formed by a roller which is mounted on the first support (22) so as to be freely rotatable about a second rotation axis (x2) parallel to the first rotation axis (x1) and which has a circumferential cutting edge.

3. The device according to any one of the preceding claims, wherein: The calibration tool (36) is configured to widen a pipe section (P) of the pipe (T) by plastic deformation.

4. The device according to any one of claims 1 to 2, wherein: The calibration tool (36) is provided with a cutting edge which is suitably shaped to widen the tube section (P) of the tube (T) by chip removal.

5. A machine for processing tubes (T), in particular for straightening and cutting tubes coming from coils, comprising a device for orbital cutting and calibration of tubes according to any one of the preceding claims.

6. The machine according to claim 5, configured to perform the following steps: While the rotor (18) is rotating, a pipe section (P) is cut from the pipe (T) by a cutting tool (24); axially moving the pipe section (P) away from the remainder of the pipe (T); displacing the calibration tool (36) radially towards the longitudinal axis of the tube (T) until it reaches a predetermined position within the radial dimension of the tube (T); axially moving the pipe section (P) towards a calibration tool (36); As the rotor (18) rotates, a calibration tool (36) is moved radially outward to produce an enlargement of the inner diameter of the pipe section (P).

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