Apparatus and method for cutting end portions of a shielding foil of a shielded power cable

Abstract

A device (10) for cutting the end portion (3a) of the shielding foil (3) of a shielded power cable (1) is described, which covers at least one conductor (2, 20) having a cover layer (5, 50), wherein the end portion (3a) of the shielding foil (3) is exposed. The device (10) includes: a clamping device (11) for clamping the end portion (1a), the device (11) including an opening (22, 23) for the cable (1) to pass through, and the device (11) being rotatable about a rotation axis (X) passing through the opening (22, 23) to rotate the cable (1) during the cutting operation; and the clamping device is used to... (11) A drive device (52, 53; M2, M3) for rotating relative to the axis of rotation (X); a laser source (18) for performing the operation of cutting the end portion (3a) of the shielding foil (3); a moving device (19) configured to move the laser source (18) at least in the radial direction (Z) relative to the axis of rotation (X) to change the distance (L) from the axis of rotation (X) to the laser source (18) during the cutting operation according to the change in the value of the distance (D) from the axis of rotation (X) to the shielding foil (3), which is measured along a straight line connecting the axis of rotation (X) and the laser source (18).

Description

Technical Field

[0001] This invention relates to an apparatus and method for cutting the end portion of the shielding foil of a shielded power cable.

[0002] The present invention also relates to a clamping device for clamping shielded power cables.

[0003] This invention is applicable to the field of shielded power cables, and particularly to the field of bipolar or multipolar cables. Background Technology

[0004] Known shielded power cables include one or more dielectrically insulated conductors and are provided with one or more shielding layers made of conductive material, which serve as electromagnetic shielding to eliminate or at least limit electromagnetic interference (EMI).

[0005] Known cables (such as coaxial cables) have a single center conductor, typically made of copper, wrapped in an electrical insulation material (dielectric) layer, typically made of polyethylene or PTFE, which separates the center core from one or more outer shielding layers.

[0006] Generally, the shielding layer includes a shielding foil of conductive material (known in the art as the English term "foil"), for example, a thin, preferably multilayered aluminum-based film wrapped around an electrically insulating material layer, and a shielding braid including a foil wrapped around the underlying material.

[0007] There is also an outer cable insulation sheath used to surround the aforementioned layers and components.

[0008] It is also known that a bipolar cable has two adjacent conductors, each of which is individually wrapped in a corresponding electrical insulating material (dielectric) layer, and one or more shielding layers generally comprising a shielding foil covering the two conductors, which are individually wrapped in electrical insulating material layers.

[0009] This bipolar cable also has a shielding braid made of strands that surrounds the shielding foil made of conductive material.

[0010] It is known that the shielding foil can be made of, for example, multiple layers of aluminum-based foil of varying thicknesses (typically between 0.05 mm and 0.3 mm), but is not limited thereto, the shielding foil being arranged around the dielectric of the conductor (or generally one or more conductors) covering the shielded power cable.

[0011] In other words, the foil that forms the additional shield of the cable is typically inserted between the electrical insulation material (dielectric) and the braid.

[0012] As described, the outer layer of the shielding braid has a protective sheath, typically made of electrically insulating material.

[0013] Shielded power cables may further include electrical connectors that connect to the ends of the power cable. For example, in order to constrain the connector to the end portion of a coaxial or bipolar cable, the end portion of the power cable must be prepared by performing a method that typically includes the following steps: Remove a portion of the outer protective sheath, thereby exposing a predetermined length of shielding braid at the end of the power cable; Remove or flip a portion of the exposed shielding braid backward (i.e., in the opposite direction to the free end or end portion of the cable in operation) to shorten the exposed portion of the shielding braid, thereby obtaining the final portion of the cable end portion with exposed shielding foil. A portion of the shielding foil is removed to shorten the exposed portion of the shielding foil, thereby obtaining the final portion of the cable end with exposed dielectric.

[0014] Removing the shielding foil is a crucial step in the process of preparing the end portion of a shielded power cable.

[0015] Some known techniques involve using a laser source to remove the shielding foil.

[0016] The shielded cable is inserted into the support cavity, and the end portion, including the shielding foil to be removed, is cut using a laser source.

[0017] In known systems, a laser source rotates around a cable to perform cutting of the shielding foil, or the laser source remains in a fixed position while the cable rotates around a rotation axis.

[0018] In other words, devices known in the art provide the means to rotate the cable and the laser source relative to each other about the axis of the cable, thereby determining the cutting of the foil and its separation from the cable.

[0019] The removal of the foil formed by means of such known equipment may be non-uniform, that is, the cutting profile of the foil is non-uniform, because it depends on the distance between the shielding foil and the cutting source: in particular, in the case of bipolar cables, that is, those cables that consist of two adjacent conductive cables, the diameter of the cable is variable, and in particular it has an elliptical cross-section with a major axis and a minor axis.

[0020] Furthermore, a drawback of devices known in the art is that the available devices for clamping and locking cables generally comprise a pair of elements movable between an operating position for locking the cable and a non-operating position for releasing the cable, in which the cable is held between the pair of locking elements. For example, such devices are configured as clamps.

[0021] Similar devices create dead angles relative to the laser beam when rotating the cable relative to the laser source to perform foil cutting. Therefore, different operations of rotating the cable and different passes of the laser beam are required to complete the operation of cutting or removing the shielding foil.

[0022] Furthermore, the shape of the cavity of the clamping and locking device is not well-suited for non-circular cables, such as bipolar cables whose cross-section is not perfectly circular.

[0023] The purpose of this invention is to overcome the shortcomings of the prior art, and in particular the aforementioned shortcomings of the method for removing shielding foil using a laser source, and to provide a method and apparatus for preparing the end portion of a shielded power cable, which can cut and remove the end portion of the shielding foil with high precision, thereby forming a clean and uniform cut profile.

[0024] A further object of the present invention is to provide a method and apparatus for preparing the ends of a shielded power cable, which can remove the shielding foil in a uniform manner without the risk of damaging the foil and / or conductors (or multiple conductors) of the shielded power cable.

[0025] A further object of the present invention is to provide a method and apparatus for removing the shielding foil of a shielded power cable, which is versatile and can be used in conjunction with different types of shielded cables, particularly with multipole cables. Summary of the Invention

[0026] These and other objectives are achieved by means of the device for cutting and removing the end portion of the shielding foil of a shielded power cable according to independent claim 1, the method according to independent claim 8, and the cable clamping device according to claim 14.

[0027] Further features / aspects of the invention are described and / or set forth in the dependent claims below. It should be noted first that the content described and / or claimed herein with reference to the method is applicable to the device, and vice versa.

[0028] An apparatus for removing an end portion of a shielding foil from a shielded power cable, wherein the end portion of the cable has at least one layer of shielding foil covering at least one conductor having a layer covering the shielded power cable (in other words, the shielding foil is placed outside the insulating covering layer of at least one conductor), and wherein at least one end portion of the shielding foil is exposed, the apparatus comprising: - A clamping device for clamping the end portion; the device includes an opening through which the cable passes and the device is rotatable about a rotation axis passing through the opening to rotate the cable during a cutting operation; - A drive mechanism for rotating the clamping device relative to the axis of rotation; - A laser source used to perform the operation of cutting the end portion of the shielding foil; - A moving device configured to move the laser source at least radially relative to the axis of rotation to change the distance from the axis of rotation to the laser source during the cutting operation according to a change in the value of the distance from the axis of rotation to the shielding foil, the value being measured along a straight line connecting the axis of rotation and the laser source.

[0029] Advantageously, with the aid of this device, portions of the shielding foil can be cut from cables of any cross-section without damaging the conductor underneath.

[0030] In particular, with the aid of such a device, portions of the shielding foil can be cut from non-coaxial (e.g., bipolar) cables, and thus the cable does not have a circular cross-section but rather an elliptical or any other shape, such that it does not have a uniform and constant radius but has at least one short axis and one long axis.

[0031] In fact, by rotating the cable, in which the conductor (and therefore the shielding foil covering it) is not arranged so that the cable as a whole has a circular cross-section, the distance from the axis of rotation of the cable to the shielding foil and the focal plane of the laser source change during the rotation of the cable.

[0032] It should be noted that the radial direction of the laser source drive is preferably the straight line connecting the rotation axis and the laser source. In other words, the laser source can move along the straight line, taking into account the axis of the laser beam.

[0033] According to a preferred aspect, during the cutting operation, the axis of the laser beam is radial relative to the axis of rotation of the cable. As a result, the thickness of the foil to be laser-cut remains substantially constant.

[0034] In other words, the axis of the laser beam is radial with respect to the cable and always acts on the foil along the thickness direction. Thanks to this, the amount of foil to be laser-cut is essentially constant over time, so the laser does not need to be changed in terms of emission power or different holding times for different cable areas.

[0035] This simplifies the cutting process and provides the further advantage of lower energy consumption.

[0036] It should be noted that the focal plane is a plane that passes through the focal point, is perpendicular to the axis of the laser beam, and is located at a distance equal to the focal length of the laser source.

[0037] With the help of this device, thanks to the combination of the rotational motion of the cable and the translation of the laser source relative to the axis of rotation, uniform cutting of the shielding foil can be achieved, which allows the focal plane of the laser source to remain tangent to the point of the shielding foil to be cut.

[0038] Conversely, devices known in the art achieve non-uniform cutting of the shielding foil.

[0039] According to one aspect, the device includes a detection device configured to monitor in real time the value of the distance from the axis of rotation to the shielding foil, the value being measured along a straight line connecting the axis of rotation and the laser source during the rotation of the cable.

[0040] Advantageously, during the rotation of the cable being cut, the detection device allows the shape, position, and arrangement of the conductors of the machined cable to be known by means of, for example, a camera or other sensors, and thus allows the laser source to be displaced such that it maintains the proper focal length with respect to the cutting point.

[0041] This factor allows for minimizing potential damage to the cable caused by the laser source and the shielding foil being cut being too close, and ensures accurate and sufficient laser power calibration.

[0042] According to one aspect, the moving device of the laser source is configured to move the laser source in a radial direction relative to the axis of rotation whenever the value of the distance detected at a given moment is different from the value of the distance detected at a previous moment.

[0043] It should be noted that the mobile device is suitable for moving the laser source when it is too close to or too far from the shielding foil.

[0044] According to one aspect, the moving device is configured to move the laser source away from the rotation axis whenever the value of the distance detected at a certain moment is greater than the value of the distance detected at a previous moment, and is configured to move the laser source closer to the rotation axis whenever the value of the distance detected at a certain moment is less than the value of the distance detected at a previous moment.

[0045] Advantageously, the detection of the distance from the shielding foil to the laser source occurs in real time because the control of the laser source's movement mechanism occurs in real time during the cable's rotation. This allows for the synchronous movement of the laser source and the clamping device used to hold the cable, thereby allowing the cable to rotate.

[0046] According to one aspect, the moving device for moving the laser source is configured to change the distance such that during the rotation of the cable, the focal plane of the laser source coincides with a cutting plane that is tangent to the end portion at the cutting point of the laser beam.

[0047] According to one aspect, the device includes an air source that is supplied at a temperature between -40°C and -20°C, and preferably equal to -30°C.

[0048] Advantageously, this low-temperature air source allows for the avoidance of damage caused by heat generated by the laser beam during the cutting of the shielding foil.

[0049] According to one aspect, the apparatus includes a removal device for removing the end portion of the shielding foil cut by means of the laser source.

[0050] For example, the removal device may include a clamp or a suction tube for debris.

[0051] Removing the shielding foil means removing the foil portion from the end of the cable, and as described, this removal can be advantageously carried out in a simple and quick manner by moving the removal device or by suctioning the debris or a combination thereof.

[0052] According to one aspect, the device includes a control logic unit that is at least electronically connected to the drive mechanism for the clamping and / or to the laser source and / or to the moving mechanism for the laser source and / or to the detection mechanism.

[0053] The present invention also relates to a method for cutting the end portion of a shielding foil of a shielded power cable, using the apparatus according to any one of the preceding claims, wherein the shielding foil covers at least one conductor having a covering layer, and wherein at least one end portion of the shielding foil is exposed, the method comprising the following steps: a) Insert the end portion of the cable into the clamping device and lock it in the clamping position; b) Determine the value of the distance from the rotation axis to the shielding foil, which is measured along a straight line connecting the rotation axis and the laser source; c) Operate the drive device to rotate the clamping device relative to the rotation axis to rotate the cable; d) Drive the laser source to cut the end portion of the shielding foil during the rotation of the cable; e) Drive the moving device to move the laser source to change the distance from the rotation axis to the laser source during step d) according to the change in the value of the distance from the rotation axis to the shielding foil.

[0054] As described above, during step e), the laser source typically moves radially relative to the axis of rotation of the cable along a straight line connecting the axis of rotation and the laser source, i.e., the laser source is movable along the straight line taking into account the axis of the laser beam.

[0055] Therefore, during step d), the axis of the laser beam is typically maintained in the radial direction relative to the axis of rotation of the cable.

[0056] According to one aspect, step b) is performed by means of a detection device configured to monitor, in real time, the value of the distance from the axis of rotation to the shielding foil during the rotation of the cable.

[0057] According to one aspect, step e is performed whenever the value of the distance detected at a given moment differs from the value of the distance detected at a previous moment.

[0058] According to one aspect, in step e), whenever the value of the distance detected at a certain moment is greater than the value of the distance detected at a previous moment, the laser source is moved away from the rotation axis, and whenever the value of the distance detected at a certain moment is less than the value of the distance detected at a previous moment, the laser source is moved closer to the rotation axis.

[0059] According to one aspect, the device includes a control logic unit that is at least electronically connected to the drive mechanism for driving the clamp and / or to the laser source and / or to the moving mechanism for the laser source and / or to the detection device, and wherein steps b) to e) are performed at least in part by means of the control logic unit.

[0060] The present invention also relates to a clamping device for clamping a cable rotatable about a rotation axis, comprising:

[0061] - At least one first rotatable body having a first opening for the cable to pass through and including a pressurizing element for pressurizing the cable, and

[0062] - A second rotatable body having a second opening for the cable to pass through, the second body having a pushing element adapted to move the pressure unit element between at least one clamping position and at least one position for releasing the cable. - wherein the first body and the second body are arranged facing each other such that the corresponding openings are aligned along the axis of rotation. - and wherein the second body is rotatable relative to the first body about the axis of rotation, or vice versa, such that the pushing element acts on the clamping element which is moved to lock the end portion of the cable in the clamping position.

[0063] Advantageously, similar clamping devices allow for the simultaneous operation of adjusting cable clamping and cable rotation.

[0064] According to one aspect, the pressurizing device for the cable is movable in a radial direction relative to the axis of rotation between at least one clamping position and at least one position for releasing the cable.

[0065] Advantageously, according to this configuration, the device is suitable for machining coaxial cables, and the pressure device is shaped to complement the contour of the outer surface of the shielding foil, thereby optimally surrounding the shielding foil in the closed position.

[0066] Furthermore, the device is suitable for machining cables of the type comprising two preferably adjacent conductors, and the shape of the pressurizer device is configured to be substantially complementary to the profile of the outer surface of the shielding foil covering these preferably adjacent conductors (each conductor being equipped with a cover layer), and / or substantially complementary to the profile of the outer surface of the cover layer of the two conductors.

[0067] Advantageously, according to this configuration, the device is suitable for implementation in a device according to the invention for machining, preferably bipolar, cables.

[0068] However, the application of cables with a greater number of conductors cannot be ruled out.

[0069] According to one aspect, the first and second bodies are integrally rotatable about the axis of rotation to rotate the end portion of the cable.

[0070] According to one aspect, the clamping device includes a first operating device for the first rotatable body and a second operating device for the second rotatable body, which can operate independently or simultaneously.

[0071] According to one aspect, the first rotatable body and the second rotatable body include toothed perimeter profiles, and the first and second operating devices respectively include first and second toothed shafts.

[0072] The present invention also relates to an apparatus according to the invention for cutting the end portion of the shielding foil of a shielded power cable, the apparatus including a clamping device according to the invention. Attached Figure Description

[0073] Other aspects and advantages of the invention will become clearer from the following description, which is by way of example only and is not intended to limit the scope of the invention, referring to the schematic diagrams in the accompanying drawings, wherein: - Figure 1A and 1B A schematic side view of the ends of a bipolar cable and a coaxial cable, which can be machined using the equipment and method according to the invention; - Figure 1C It shows according to Figure 1A The bipolar cable is based on the cross-section of a plane perpendicular to the axis; - Figure 2A and 2B A portion of a cable, including the shielding braid, is schematically shown that can be machined in the apparatus according to the invention; - Figure 3 and Figure 4 Two perspective views of a possible embodiment of an apparatus for cutting the end portion of the shielding foil of a shielded power cable according to the present invention are shown; - Figure 5 A cross-sectional view of a possible embodiment of an apparatus for cutting the end portion of the shielding foil of a shielded power cable according to the present invention is shown; - Figure 6 The possible steps of the method according to the invention are illustrated schematically, wherein a laser source performs a cutting operation on the shielding foil of a cable rotating about a rotation axis; - Figure 7 A view of the transmission device used for transmitting cables is shown; - Figure 8A and 8B A front view of a cable clamping device according to a first embodiment of the present invention is shown; - Figure 9A It shows that according to Figure 8A and 8B A perspective view of the cable clamping device in an embodiment of the present invention; - Figure 9B It shows Figure 9A An exploded perspective view of a cable clamping device according to an embodiment of the present invention; Figures 10a and 10b show front views of a cable clamping device according to a second embodiment of the present invention. Detailed Implementation

[0074] Reference Figure 1A and 1B The shielded power cable 1 typically comprises at least one central conductor 2, 20 separated from the conductor or conductor 2, 20 by a layer of electrically insulating material 5, 50 (or dielectric) covering the conductor. As described, an additional shielding layer (preferably a thin multilayer film made of, for example, aluminum) consisting of shielding foil 3 is arranged between the braid 4 and the dielectric 5, 50.

[0075] For simplicity, this document refers only to conductors 2 and 20 of the cable, a term that also refers to conductors covered with electrical insulating material covering layers 5 and 50. In fact, the expression "foil 3 covering conductors 2 and 20" will be used to indicate that the foil is placed on the outside relative to the insulating covering layer 5 and 50, which has at least one conductor 2 and 20 of the cable 1.

[0076] The outer protective sleeve 6, which is also usually made of electrically insulating material, surrounds the shielding braid 4.

[0077] exist Figure 3-5 In the possible embodiments shown, the device schematically represented by reference numeral 10 throughout the figures is adapted to handle bipolar cables 1, and as... Figure 1C and 6As shown, the assembly includes two adjacent conductors 2, 20, each of which is individually wrapped in its own electrical insulating material layer (e.g., dielectric) 5, 50, and a shielding foil 3 covering the two conductors 2, 20 individually wrapped in their respective electrical insulating material layers 5, 50.

[0078] It should be noted that this type of cable, which includes two adjacent conductors, has an elliptical cross-section and therefore does not have a cross-section with a constant diameter or radius.

[0079] exist Figure 7 In the embodiment shown for illustrative purposes, device 10 includes a conveying device 17 for conveying the cable 1 and adapted to move the cable 1 toward a workstation. The conveying device 17 may include a plurality of elements movable between an operating position for locking the cable and a non-operating position for releasing the cable, in which the cable is held between a plurality of locking elements. Such a conveying device 17 may be configured as a clamp, for example, and the locking / releasing of the cable may be operated using different methods, such as hydraulic, pneumatic, or electric actuators.

[0080] Reference Figure 2A and 2B In a possible embodiment, the end portion 1a of the power cable 1 is typically pre-arranged by removing a portion of the protective sheath 6 of a given length, thereby exposing the shielding braid 4 (if any) of the end portion 1a of the power cable 1.

[0081] Whenever the cable 1 has the shielding braid 4, the cable can be prepared to continuously remove the foil 3, for example by methods known in the art, which flip the shielding braid 4 and are adapted to fold the end portions of the shielding braid so that the end portions of the underlying foil 3 are exposed.

[0082] exist Figure 2B In the illustrated possible embodiment, the exposed portion of the shielding braid 4 is preferably locked by a locking device 133, which is adapted to securely hold a portion of the shielding braid and fold it by a device for flipping the shielding braid 4, which is adapted to fold the end portion 4a of the shielding braid 4 over the locking device 133, thereby exposing the end portion 3a of the underlying shielding foil 3. Thus, the end portion 1a of the shielded power cable 1, thus pre-arranged, is ready for the step of removing the end portion 3a of the shielding foil 3.

[0083] In fact, due to the flipping of the braid, at least one end portion 3a of the shielding foil 3 is exposed for machining and is not covered by the shielding braid 4.

[0084] According to the device 10 of the present invention, suitable for cutting the end portion 3a of the shielding foil 3 of a shielded power cable 1, the device includes a clamping device 11 for clamping the end portion 1a, the clamping device 11 having openings 22, 23 for the cable 1 to pass through, and the clamping device 11 is rotatable about a rotation axis X passing through the openings 22, 23 to rotate the cable 1 during the cutting operation.

[0085] The clamping device 11 will be described in detail below, which is also the purpose of this invention.

[0086] It should be noted that, in the preferred embodiment, the openings 22 and 23 for allowing the cable 1 to pass through and for clamping the cable 1 have a circular cross-section, but embodiments in which the openings 22 and 23 for allowing the cable to pass through and for clamping the cable have an elliptical or polygonal cross-section are not excluded.

[0087] The device 10 according to the invention further includes drive devices 52, 53; M2, M3 for rotating the clamping device 11 relative to the rotation axis X.

[0088] Reference Figure 3 and Figure 4 The drive device may include at least one motor element M2, M3 (e.g., an electric motor or a servo motor) and at least one motion transmission element 52, 53 (e.g., at least one shaft 52, 53 that transmits rotation to the clamping device 11).

[0089] The controllable drive devices 52, 53; M2, M3 cause the operating clamping device 11 to rotate in a clockwise and / or counterclockwise direction and to impart and adjust the required angular velocity to the rotating device.

[0090] In an embodiment, the clamping device 11 can rotate about the rotation axis X in a clockwise and / or counterclockwise direction.

[0091] The device 10 according to the invention further includes a laser source 18 for performing the operation of cutting the end portion 3a of the shielding foil 3.

[0092] Reference Figure 3-5 The laser source 18 is placed above the clamping device 11, and particularly positioned above the clamping device 11 in the radial direction Z, but embodiments in which the laser source 18 is placed below or beside the clamping device 11 are not excluded.

[0093] The device 10 further includes a moving device 19 configured to move the laser source 18 at least along a radial direction Z relative to the rotation axis X, so as to change the distance L from the rotation axis X to the laser source 18 during the cutting operation according to the change in the value of the distance D from the rotation axis X to the shielding foil 3, which is measured along a straight line connecting the rotation axis X and the laser source 18. Figure 6The diagram shown is for illustrative purposes.

[0094] The direction Z typically coincides with the straight line connecting the rotation axis X and the laser source 18. In other words, during the cutting of the shielding foil 3, the laser beam emitted by the laser source 18 has an axis arranged radially relative to the rotation axis. Therefore, the axis of the laser is arranged in direction Z, which is the driving direction of the laser source 18. The cutting of the shielding foil 3 is performed by means of a laser beam having an axis arranged radially relative to the rotation axis X.

[0095] It should be noted that the distance D from the rotation axis X to the shielding foil 3, measured along the straight line connecting the rotation axis X and the laser source 18, corresponds to the precise value of the cross-sectional radius of the cable 1, which is measured at a given moment along the straight line connecting the rotation axis X and the laser source 18.

[0096] Whenever the cable is a coaxial cable (i.e., with a circular cross-section and a constant radius), the value of the distance D from the axis of rotation X to the shielding foil 3 is constant, while whenever the cable 1 is, for example, a bipolar cable (i.e., with an elliptical cross-section and a major axis and a minor axis), the value is non-uniform.

[0097] In a possible embodiment, the moving device 19 for moving the laser source 18 includes, for example, a vertical guide extending in a radial direction Z relative to the axis of rotation, having a motorized slider on which the laser head 18 is mounted.

[0098] As will be referred to below Figure 5 or Figure 6 To explain it better, the value of the distance D from the rotation axis X to the shielding foil 3 can be used to move the laser source 18 closer to and further away from the rotation axis X, which is measured along the straight line connecting the rotation axis X and the laser source 18.

[0099] In an embodiment, device 1 includes a detection device 60 configured to monitor in real time the value of the distance D from the rotation axis X to the shielding foil 3, wherein the value is measured along a straight line connecting the rotation axis and the laser source 18 during the rotation of cable 1.

[0100] For example, detection device 60 may include a camera and / or sensors (e.g., horizontal or position sensors).

[0101] Reference Figure 5 and Figure 6 The moving device 19 of the laser source 18 is configured to move the laser source 18 in the radial direction Z relative to the rotation axis X whenever the value of the distance D detected at a given time t1 is different from the value of the distance D detected at a previous time t0.

[0102] Specifically, refer to Figure 6The moving device 19 of the laser source 18 is configured to move the laser source 18 away from the rotation axis X whenever the value of the distance D detected at a certain time t1 is greater than the value of the distance D detected at the previous time t0, and is configured to move the laser source 18 closer to the rotation axis X whenever the value of the distance D detected at a certain time t1 is less than the value of the distance D detected at the previous time t0.

[0103] In other words, the moving device 19 of the laser source 18 is configured to move the laser source 18 away from the rotation axis X whenever the precise value of the radius r of the cable 1 detected at a certain time t1 is greater than the precise value of the radius r of the cable 1 detected at the previous time t0, and is configured to move the laser source 18 closer to the rotation axis X whenever the precise value of the radius r of the cable 1 detected at a certain time t1 is less than the precise value of the radius r of the cable 1 detected at the previous time t0.

[0104] In a preferred embodiment, the moving device 19 of the laser source 18 is configured to change the distance L such that during the rotation of the cable 1, the focal plane F of the laser source 18 coincides with the cutting plane T, wherein the cutting plane at the cutting point of the laser beam is identified in a plane tangent to the end portion 3a of the shielding foil 3.

[0105] Reference Figure 4 and Figure 5 The device 10 includes an air source 7, which is supplied at a temperature between -40°C and -20°C, and preferably equal to -30°C.

[0106] Preferably, air is supplied only during the cutting operation (i.e., during the step of operating the laser source 18) to cool the surface of the end portion 3a of the shielding foil 3 when cutting.

[0107] exist Figure 3-5 In the embodiment shown for illustrative purposes only, the device 10 includes a removal device 8 for removing the end portion 3a of the shielding foil 3 cut by means of the laser source 18.

[0108] Reference Figure 5 The removal device 8 may include a clamp 81 and / or a suction tube 82.

[0109] In an embodiment, the device includes a control logic unit 100, which is at least electronically connected to drive devices 52, 53 for clamping device 11; M2, M3 and / or to laser source 18, and / or to moving device 19 for laser source 18 and / or to detection device 60 for detecting distance D from rotation axis X to shielding foil 3.

[0110] In particular, the control logic unit 100 is programmed to operate the drive devices 52, 53; M2, M3 for rotating the clamping device 11, so as to rotate the cable 1 and drive the laser source 18 during the cutting operation.

[0111] Furthermore, the control logic unit 100 is programmed to drive the moving device 19 for the laser source 18 based on the value of the distance D detected from the rotation axis X to the shielding foil 3.

[0112] In particular, the detection device 60 is configured to detect the precise value of the distance D from the rotation axis X to the shielding foil 3, and is configured to send a corresponding signal indicating the value of the distance D to the control logic unit 100.

[0113] As described above, whenever the precise value of the distance D from the rotation axis X to the shielding foil 3 detected at a certain moment t1 is greater than or less than the precise value of the distance D from the rotation axis X to the shielding foil 3 detected at a previous moment t0, the logic unit 100 drives the moving device 19 for the laser source 18.

[0114] A method for cutting portions of the shielding foil 3, using the apparatus according to the invention, will now be described.

[0115] The method for cutting the end portion 3a of the shielding foil 3 of the cable 1 according to the present invention includes a first step a of inserting the end portion 1a of the cable 1 into the clamping device 11 to lock it in the clamping position.

[0116] The method according to the invention includes a second step (b) of determining the value of the distance D from the rotation axis X to the shielding foil 3.

[0117] Reference Figure 6 The distance D is measured along the straight line connecting the rotation axis X and the laser source 18.

[0118] It should be noted that, in a possible embodiment, step b) can be performed by means of a detection device 60, which is configured to monitor the value of the distance D from the rotation axis X to the shielding foil 3 in real time during the rotation of the cable 1.

[0119] The method according to the invention further includes step c, which involves operating drive devices 52, 53; M2, M3 to rotate clamping device 11 relative to the rotation axis X to rotate the cable.

[0120] Then, or simultaneously, the method includes step d, driving the laser source 18 to cut the end portion 3a of the shielding foil 3 during the rotation of the cable 1.

[0121] The laser source 18 can be adjusted during the cutting operation, for example, by changing the emitted power.

[0122] The method according to the invention further includes step c): driving the moving device 19 to move the laser source 18 to change the distance L from the rotation axis X to the laser source 18 according to the change in the value of the distance D from the rotation axis X to the shielding foil 3 during the operation step d) of the laser source.

[0123] In this embodiment, whenever the value of the distance D detected at a given time t1 is different from the value of the distance D detected at a previous time t0, step e is performed to drive the moving device 19 to move the laser source 18.

[0124] More specifically, during step e), whenever the value of distance D detected at a certain time t1 is greater than the value of distance D detected at a previous time t0, the laser source 18 is moved away from the rotation axis X, and whenever the value of distance D detected at a certain time t1 is less than the value of distance D detected at a previous time t0, the laser source 18 is moved closer to the rotation axis X.

[0125] In an embodiment, device 1 includes a control logic unit 100, which is at least electronically connected to drive devices 52, 53 for driving clamping device 11; M2, M3 and / or to laser source 18 and / or to moving device 19 for laser source 18 and / or to detection device 60, and steps b) to e) are performed at least in part by means of control logic unit 100.

[0126] At the end of the cutting operation, the removal device 8 is operated to remove the end portion 3a of the shielding foil 3 cut by means of the laser source 18.

[0127] As mentioned above Figure 5 The disclosed removal device 8 may include a clamp 81 and / or a suction tube 82.

[0128] In particular, in a preferred embodiment, a clamp 81 equipped with suitable clamping elements moves toward the cable 1, removes the fragments of the cut portion of the shielding foil 3, pulls them from the end portion of the cable and causes them to fall into a collection container, where they are then sucked out by a suitable conduit 82.

[0129] At the end of the operation, the cable clamping device 11, which remains in the clamping position, rotates in the opposite direction by the same angular distance traveled during the cutting operation, effectively returning the cable 1 to its initial position and thus releasing it.

[0130] To complete the process, the transmission device 17 clamps the cable 1 again, and then only the second rotatable body 13 of the clamping device 11 rotates in the opposite direction to the first body 12 by the same angular distance traveled during the cutting operation, thereby allowing the pressurizer elements 31, 32, 33 to return to the initial position of releasing the cable 1.

[0131] As described above, the device 10 includes a clamping device 11 for the cable 1.

[0132] The invention further relates to a similar clamping device 11, which can be used in conjunction with the device 10 according to the invention, or as a clamping device for cable 1 in conjunction with different devices belonging to the known art for machining cable end portions.

[0133] Reference Figures 8A-8B According to 9A-9B and 10A-10B, the clamping device 11 for cable 1 according to the present invention is rotatable about a rotation axis X and includes at least one first rotatable body 12 and a second rotatable body 13. The first rotatable body 12 is provided with a first opening 22 for cable 1 to pass through and includes pressure elements 31, 32, and 33 for cable 1. The second rotatable body 13 is provided with a second opening 23 for cable 1 to pass through and includes pushing elements 41, 42, and 43. The pushing elements 41, 42, and 43 are adapted to move the pressure elements 31, 32, and 33 between at least one clamping position and at least one position for releasing cable 1.

[0134] The first body 12 and the second body 13 are arranged facing each other, such that the corresponding openings 22 and 23 are aligned along the axis of rotation X.

[0135] The second body 13 is rotatable relative to the first body 12 about the rotation axis X, or vice versa, such that the pushing elements 41, 42, 43 act on the clamping elements 31, 32, 33 that are moved to lock the end portion of the cable 1 in the clamping position.

[0136] exist Figure 8A and 8B In the embodiment shown for illustrative purposes, the clamping elements 31, 32, 33 include a plurality of terminals, preferably three terminals 31, 32, 33, arranged on the first body 12 in a radial direction relative to the axis of rotation X.

[0137] Thus, the pressurizing devices 31, 32, and 33 for cable 1 are movable in the radial direction relative to the rotation axis X between at least one clamping position and at least one position for releasing cable 1.

[0138] Reference Figures 8A-8B In the embodiments shown in 9A-9B, the pushing elements 41, 42, 43 acting on the clamping elements 31, 32, 33 include a plurality of protrusions, preferably three protrusions 41, 42, 43, which protrude toward the center of the second body. Each protrusion is shaped on the inner circumferential surface of the second body 13, thereby having a tapered segment (i.e., having a variable distance relative to the axis of rotation X) to allow the ends of the respective terminals 31, 32, 33 to slide.

[0139] exist Figures 8A-8B In the embodiments shown in 9A-9B, each pressure element 31, 32, 33 has an end with cams 31', 32', 33' that can slide along corresponding protrusions having tapered sections 41, 42, 43.

[0140] Therefore, as described above, the second body 13 is rotatable relative to the first body 12 about the rotation axis X, or vice versa, such that the pushing elements 41, 42, 43 act on the clamping elements 31, 32, 33, which are moved in the radial direction relative to the rotation axis X to lock the end portion of the cable 1 in the clamping position. The pushing action on the terminals 31, 32, 33 is generated by the rotation of the second body 13. By rotating, the second body 13 causes the cams 31', 32', 33' of the terminals 31, 32, 33 to slide along the tapered protrusions of the pushing elements 41, 42, 43 that protrude toward the center of the second body 13.

[0141] It should be noted that in this embodiment, each pressurizer device 31, 32, 33 is provided with a resilient return element 31”, 32”, 33”, which allows the pressurizer device 31, 32, 33 to return to the position of the release cable 1.

[0142] exist Figures 10A-10B In the alternative embodiments shown, the pushing elements 41, 42, 43 acting on the clamping elements 31, 32, 33 include a plurality of guides, preferably three guides 41, 42, 43, which are formed on the surface of the second body 13 and each guide is shaped on the second body 13 to allow the end of the corresponding terminal 31, 32, 33 to slide.

[0143] Also in Figures 10A-10B In the illustrated embodiment, each pressurizer element 31, 32, 33 has an end provided with cams 31', 32', 33', which can slide along corresponding guides 41, 42, 43 formed on the second body 13.

[0144] Therefore, as described above, the second body 13 is rotatable relative to the first body 12 about the rotation axis X, or vice versa, such that the pushing elements 41, 42, 43 act on the clamping elements 31, 32, 33, which are moved in the radial direction relative to the rotation axis X to lock the end portion of the cable 1 in the clamping position. The pushing action on the terminals 31, 32, 33 is generated by the rotation of the second body 13, which causes the cams 31', 32', 33' of the terminals 31, 32, 33 to slide along the forming guide of the pushing elements 41, 42, 43.

[0145] By reversing the rotation direction of the second body 13, the cams 31', 32', and 33' of the terminals 31, 32, and 33 slide in the opposite direction along the forming guides of the pushing elements 41, 42, and 43, thereby returning the device 11 to the position of releasing the cable 1.

[0146] In an embodiment, the first and second bodies 12, 13 are further integrally rotatable about a rotation axis X to rotate the end portion of the cable 1.

[0147] In this respect, the device 11 includes a first operating device 52 for the first rotatable body 12 and a second operating device 53 for the second rotatable body 13, which can operate independently or simultaneously.

[0148] It should be noted that, as described above, because the second body 13 rotates relative to the second body 12, the cable is clamped by operating only the first operating device 52 for rotating the first rotatable body 12, so that the pressurizing devices 31, 32, 33 move toward the cable clamping position.

[0149] By simultaneously operating the first and second operating devices 52 and 53, the two bodies 12 and 13 rotate as a unit (i.e. simultaneously), allowing the cable 1, which is locked in the clamping position, to rotate.

[0150] In the embodiment, the first rotatable body 12 and the second rotatable body 13 include an external toothed perimeter profile, and the first and second operating devices 52 and 53 respectively include the first and second toothed shafts 52 and 53.

[0151] Thus, when the toothed shafts 52 and 53 rotate (e.g. by means of a corresponding electric motor or servo motor), they operate the rotatable bodies 12 and 13 of the clamping device 11.

Claims

1. A device (10) for cutting the end portion (3a) of a shielding foil (3) of a shielded power cable (1), which covers at least one conductor (2, 20) having a cover layer (5, 50), wherein the end portion (3a) of the shielding foil (3) is exposed, the device (10) comprising: - Clamping device (11) for clamping the end portion (1a), the device (11) includes openings (22, 23) for the cable (1) to pass through and the device (11) is rotatable about a rotation axis (X) passing through the openings (22, 23) to rotate the cable (1) during the cutting operation; - Drive devices (52, 53; M2, M3) for rotating the clamping device (11) relative to the rotation axis (X); - A laser source (18) is used to perform the operation of cutting the end portion (3a) of the shielding foil (3); - A moving device (19) configured to move the laser source (18) at least in a radial direction (Z) relative to the rotation axis (X) to change the distance (L) from the rotation axis (X) to the laser source (18) during the cutting operation according to the change in the value of the distance (D) from the rotation axis (X) to the shielding foil (3), which is measured along a straight line connecting the rotation axis (X) and the laser source (18).

2. The device (10) according to claim 1, wherein the radial direction Z coincides with the axis of the laser beam emitted by the laser source (18) under operating conditions.

3. The device (10) according to claim 1 or 2, the device (10) includes a detection device (60) configured to monitor in real time the value of the distance (D) from the rotation axis (X) to the shielding foil (3), the value being measured along a straight line connecting the rotation axis (X) and the laser source (18) during the rotation of the cable (1).

4. The device (10) according to claim 1, 2 or 3, wherein the moving device (19) of the laser source (18) is configured to move the laser source (18) in the radial direction (Z) relative to the rotation axis (X) whenever the value of the distance (D) detected at a given time (t1) is different from the value of the distance (D) detected at a previous time (t0).

5. The device (10) according to any one of the preceding claims, wherein the moving device (19) is configured to move the laser source (18) away from the rotation axis (X) whenever the value of the distance (D) detected at a certain moment (t1) is greater than the value of the distance (D) detected at a previous moment (t0), and is configured to move the laser source (18) closer to the rotation axis (X) whenever the value of the distance (D) detected at a certain moment (t1) is less than the value of the distance (D) detected at a previous moment (t0).

6. The device (10) according to any one of the preceding claims, wherein the moving device (19) for moving the laser source (18) is configured to change the distance (L) such that during the rotation of the cable (1), the focal plane (F) of the laser source (18) coincides with the cutting plane (T) that is tangent to the end portion (3a) at the cutting point of the laser beam.

7. The device (10) according to any one of the preceding claims includes an air source (7) that supplies air at a temperature between -40°C and -20°C and preferably equal to -30°C.

8. The device (10) according to any one of the preceding claims includes a removal device (8) for removing the end portion (3a) of the shielding foil (3) cut by means of the laser source (18).

9. The device (10) according to any one of the preceding claims, the device (10) comprising a control logic unit (100) at least electronically connected to the drive device (52, 53; M2, M3) for the clamping device (11) and / or to the laser source (18) and / or to the moving device (19) for the laser source (18) and / or to the detection device (60).

10. A method for cutting an end portion (3a) of a shielding foil (3) of a shielded power cable (1), using an apparatus (10) according to any one of claims 1 to 8, wherein the shielding foil (3) covers at least one conductor (2, 20) having a cover layer (5, 50), wherein at least one end portion (3a) of the shielding foil (3) is exposed, the method comprising the steps of: a) Insert the end portion (1a) of the cable (1) into the clamping device (11) and lock it in the clamping position; b) Determine the value of the distance (D) from the rotation axis (X) to the shielding foil (3), which is measured along a straight line connecting the rotation axis (X) and the laser source (18); c) Operate the drive device (52, 53; M2, M3) to rotate the clamping device (11) relative to the rotation axis (X) to rotate the cable (1); d) Drive the laser source (18) to cut the end portion (3a) of the shielding foil (3) during the rotation of the cable (1); e) Drive the moving device (19) to move the laser source (18) to change the distance (L) from the rotation axis (X) to the laser source (18) during step d) according to the change in the value of the distance (D) from the rotation axis (X) to the shielding foil (3).

11. The method according to claim 10, wherein, In step d), the axis of the laser beam is radial relative to the axis of rotation (X).

12. The method according to claim 10 or 11, wherein, In step e), the laser source moves along the axis of the laser beam.

13. The method according to any one of claims 10 to 12, wherein step b) is performed by means of a detection device (60) configured to monitor in real time the value of the distance (D) from the axis of rotation (X) to the shielding foil (3) during the rotation of the cable (1).

14. The method according to any one of claims 10 to 13, wherein step e is performed whenever the value of the distance (D) detected at a given time (t1) is different from the value of the distance (D) detected at a previous time (t0).

15. The method according to any one of claims 10 to 14, wherein, In step e), whenever the value of the distance (D) detected at a certain moment (t1) is greater than the value of the distance (D) detected at a previous moment (t0), the laser source (18) is moved away from the rotation axis (X), and whenever the value of the distance (D) detected at a certain moment (t1) is less than the value of the distance (D) detected at a previous moment (t0), the laser source (18) is moved closer to the rotation axis (X).

16. The method according to any one of claims 10 to 15, wherein the device (10) comprises a control logic unit (100) at least electronically connected to the driving device (52, 53; M2, M3) for driving the clamping device (11) and / or to the laser source (18) and / or to the moving device (19) for the laser source (18) and / or to the detection device (60), and wherein steps b) to e) are performed at least in part by means of the control unit logic (100).

17. A clamping device (11) for clamping a cable (1) rotatable about a rotation axis (X), comprising: - At least one first rotatable body (12) having a first opening (22) for the cable (1) to pass through and including pressure-pressurizing elements (31, 32, 33) for pressurizing the cable (1), and - A second rotatable body (13) having a second opening (23) for the cable (1) to pass through, the second body (13) having a pushing element (41, 42, 43) adapted to move the pressure unit element (31, 32, 33) between at least one clamping position and at least one position for releasing the cable (1). The first body (12) and the second body (13) are arranged facing each other, such that the corresponding openings (22, 23) are aligned along the axis of rotation (X). And wherein the second body (13) is rotatable relative to the first body (12) about the rotation axis (X), or vice versa, such that the pushing elements (41, 42, 43) act on the clamping elements (31, 32, 33) which are moved to lock the end portion of the cable (1) in the clamping position.

18. The clamping device (11) according to claim 17, wherein the pressurizing device (31, 32, 33) for the cable (1) is movable in a radial direction relative to the axis of rotation (X) between at least one clamping position and at least one position for releasing the cable (1).

19. The clamping device (11) according to claim 17 or 18, wherein the first and second bodies (12, 13) are integrally rotatable about the rotation axis (X) to rotate the end portion (1a) of the cable (1).

20. The clamping device (11) according to any one of claims 17 to 19, the clamping device (11) comprising a first operating device (52) for the first rotatable body (12) and a second operating device (53) for the second rotatable body (13), which can operate independently or simultaneously.

21. The clamping device (11) according to claim 20, wherein the first rotatable body (12) and the second rotatable body (13) include toothed perimeter profiles, and the first and second operating devices (52, 53) respectively include first and second toothed shafts (52, 53).

22. The clamping device (11) according to any one of claims 17 to 21, wherein the pushing element (41, 42, 43) acting on the clamping element (31, 32, 33) comprises a plurality of protrusions, preferably three protrusions (41, 42, 43), the plurality of protrusions protruding toward the center of the second body, each pressure device (31, 32, 33) having an end portion provided with a cam (31', 32', 33'), the cam (31', 32', 33') being slidable along the corresponding protrusion (41, 42, 43).

23. A device (10) according to any one of claims 1 to 9 for cutting the end portion (3a) of the shielding foil (3) of a shielded power cable (1), the device (10) comprising a clamping device (11) according to any one of claims 17 to 22.

Images