Machine for automatically cutting cloth

Abstract

A machine (1) for automatically cutting cloth comprises:-a cutting plane (7) at a top face (8) of a housing (3), the cutting plane comprising a plurality of through openings; a suction system (9) for sucking air from the interior (4) of the box; -a turbine (30) located downstream of the suction system and configured to extract energy from the exhaust gas stream produced by the suction system and to convert it into rotary mechanical energy; -a generator (40) mechanically coupled with the turbine (30) and configured to convert the rotational mechanical energy of the turbine into electrical energy.

Description

TECHNICAL FIELD

[0001] The present invention relates to a machine for automatic cutting of cloth or other flexible sheets (e.g. leather, artificial leather, polymeric sheets, etc.). BACKGROUND

[0002] Machines for automatic cutting of cloth are known, which are able to cut cloth arranged, for example, in a single layer or in a stack of superimposed layers (also known as "layon"), so as to cut out pieces of cloth that comply with cutting templates having specific geometrical shapes and dimensions. These pieces of cloth are generally used to manufacture clothing or other items (e.g. car interiors, furniture, etc.).

[0003] Generally, whether the cloth to be cut is in a single layer or in a layon, it is placed on a cutting plane (e.g. realized by a conveyor belt) comprising a plurality of through openings. Generally, the cutting plane is located above a box, which substantially constitutes the top face of the box.

[0004] During the cutting process, the cloth to be cut is fixed in place by means of a negative pressure (i.e. an air pressure lower than atmospheric pressure) generated inside the box, which exerts a holding force on the cloth, perpendicular to the cutting plane, through the openings. The level of negative pressure required can depend on the type of cloth, the number of layers, the type of cutting and / or the way the cutting is performed.

[0005] Patent EP 1951483 B1 describes a known automatic cutting machine. SUMMARY

[0006] In the field of machines for automatic cutting of cloth, the Applicant has found that, in order to generate the above-mentioned negative pressure, it is common to use a suction system comprising at least a fan configured and installed to suck air from inside the box.

[0007] The Applicant has faced the problem of increasing the operating efficiency of machines for automatic cutting of cloth, for example in terms of overall energy efficiency of the cutting machine.

[0008] According to the Applicant's point of view, the above-mentioned problem is solved by a machine for automatic cutting of cloth according to the appended claims and / or having one or more of the following characteristics.

[0009] According to one aspect, the present invention relates to a machine for automatic cutting of cloth, comprising:

[0010] - a box having an open top face;

[0011] - a cutting plane located on the top face of the box, comprising a plurality of through openings;

[0012] - a suction system configured to suck air from inside said tank to create a pressure difference on the opposite face of said cutting plane, said suction system generating an exhaust air flow;

[0013] - a turbomachine downstream of the suction system and configured to extract energy from said exhaust air flow and convert it into rotational mechanical energy;

[0014] - an electric generator coupled with said turbomachine and configured to convert said rotational mechanical energy of said turbomachine into electrical energy.

[0015] The terms "downstream" and "upstream" are to be understood as referring to the direction of the air flow generated by the suction system.

[0016] In the effort to solve the above problems, the Applicant has found that, during the operation of the cutting machine (in particular when the machine is started or it is necessary to increase the negative pressure), as a result of the air sucked by the suction system being discharged, a large air flow is discharged from the cutting machine itself (for example, from the bottom of the machine) and simply dispersed into the environment. However, this exhaust air flow can contain a significant amount of energy potential, which is currently wasted by the known cutting machines.

[0017] Therefore, the Applicant has realized that such an exhaust air flow can be directed to a turbomachine (for example, a turbomachine capable of collecting the energy associated with the movement of a fluid, such as kinetic and / or enthalpy energy, and converting it into rotational mechanical energy) coupled with an electric generator to generate electrical energy. This electrical energy can then be reused, for example, directly for the cutting machine itself and / or fed back into the electrical grid, thus increasing the overall operating efficiency of the machine.

[0018] In the above aspects, the present application can have one or more of the following preferred features.

[0019] Preferably, said machine comprises a load-bearing structure, more preferably at least partially constituting said tank and (additional) compartments (external to said tank) arranged alongside said tank along the main extension direction of the machine (coinciding with the direction of travel of the conveyor belt).

[0020] Preferably, said suction system is housed inside said load-bearing structure.

[0021] Preferably, said machine comprises an exhaust duct in fluid communication with said suction system for conveying said exhaust air flow. In this way, the air flow discharged by the suction system can be conveyed in an orderly and reasonable manner to the desired location, in order to avoid disturbing the operators and / or reducing the noise.

[0022] Preferably, said suction system comprises at least one suction fan, more preferably housed inside said compartments, in fluid communication with the inside of said tank and, more preferably, in fluid communication with said exhaust duct.

[0023] Preferably, said exhaust duct comprises or consists only of a first straight section, more preferably a horizontal first straight section. This helps to stabilize the air flow, for example to achieve a laminar flow regime.

[0024] Preferably, said first section has a length greater than or equal to 30 cm and / or less than or equal to 300 cm, more preferably less than or equal to 250 cm. In this way, the first section can be sufficiently long to stabilize the air flow, while not exceeding the overall dimensions of the machine.

[0025] Preferably, said first section (for example, in its entirety) is located within the footprint of said load-bearing structure, more preferably housed within said compartment. This limits the overall footprint of the machine. This limits the overall footprint of the machine.

[0026] In one embodiment, said exhaust duct comprises a second section, more preferably a straight section, even more preferably a straight section extending vertically (upwardly with respect to the direction of the air flow), located downstream of said first section. Preferably, said exhaust duct comprises a curved connection section connecting said first and second sections in a flow-continuous manner. In large cutting machines, whose typical dimensions can handle large amounts of fabric to be cut, such a second section, which extends beyond the footprint of the machine's load-bearing structure, forms a chimney for expelling large amounts of air flow away from the operators.

[0027] Preferably, said second section has a length greater than or equal to 100 cm and / or less than or equal to 400 cm, more preferably less than or equal to 300 cm. Preferably, said second section has a length greater than or equal to three times the diameter of the cross section of said second section. In this way, at the outlet of the second section, the exhaust air flow is substantially laminar.

[0028] Preferably, said turbine and said electric generator are housed within the footprint of said load-bearing structure, more preferably housed in said compartment. This arrangement provides space for the turbine and the electric generator, without altering the overall footprint of the machine.

[0029] Preferably, said turbine is operatively coupled with said exhaust duct. This enables the turbine to be surrounded by a suitably structured exhaust air flow, to maximize the efficiency of the turbine.

[0030] Preferably, said exhaust duct has a circular cross section. This facilitates the guidance of the air flow and the coupling with the turbine.

[0031] In a preferred embodiment, the turbine is located (immediately) upstream of the exhaust duct (e.g. the first section), more preferably between the suction system (e.g. the fan) and the exhaust duct (e.g. the first section), even more preferably adjacent to the fan. The Applicant has verified that this arrangement enables high energy recovery, since the airflow coming out of the fan has a high flow rate and experiences few, if any, changes in the duct cross section (where the airflow can experience pressure losses). Moreover, this position facilitates access, e.g. without having to dismount the first section of the duct.

[0032] In one embodiment (e.g. as an alternative to the preferred embodiment described above), the turbine is located (e.g. along the exhaust duct) at one end of the first section downstream with respect to the direction of the airflow (and preferably the other end of the first section corresponds to the suction fan). In this position, the airflow passing through the first section is less turbulent than the airflow coming out of the fan, which positively affects the efficiency of the turbine.

[0033] In a further embodiment (e.g. as an alternative or in combination with one of the two embodiments described above), the turbine is located (e.g. along the exhaust duct) at one end of the second section downstream with respect to the direction of the airflow (i.e. at the upper end of the chimney). The Applicant believes that a greater length of the straight section of the exhaust duct upstream of the turbine (achieved by the vertical section of the exhaust duct) enables the airflow to achieve the required laminar state.

[0034] Preferably, the exhaust duct comprises (e.g. is entirely made of) an exhaust silencer. This also simultaneously improves acoustic comfort.

[0035] Preferably, the turbine is an axial turbine (preferably with the turbine axis coinciding with the local axis of the exhaust duct, e.g. the first section or the second section). This makes the turbine particularly suitable for being easily inserted into the exhaust duct.

[0036] Preferably, the turbine is a reaction turbine. This optimizes the energy efficiency. Preferably, the turbine is a single-stage turbine, more preferably comprising a fixed stator (e.g. rigidly attached to the exhaust pipe) and a rotor rotating around the axis. Preferably, the stator comprises a fixed frame and stator elements rigidly attached to the frame, the stator elements comprising a first plurality of fixed radial vanes (typically angularly distributed in a plane perpendicular to the axis). Preferably, the rotor comprises a shaft rotating around the axis and a second plurality of radial vanes (typically angularly distributed in a perpendicular plane) fixed to the shaft. Preferably, the stator elements are located upstream of the rotor with respect to the direction of the gas flow. This helps to achieve the desired energy yield. Preferably, the shape of the first plurality and / or the second plurality of vanes is such that the gas flow exiting the turbine (from the rotor) is substantially axial. In other words, the shape of the stator and rotor vanes is such that the gas flow motion component returning from the velocity triangle of the rotor is substantially axial (e.g. within + / - 15°, more preferably within + / - 10°, with respect to the axial direction). This enables to optimize the discharge while avoiding major modifications to the geometry of the machine. Preferably, the generator comprises a stationary part and a rotating part mechanically coupled with the turbine, more preferably with the (rotor) shaft of the turbine. Preferably, one of the stationary part and the rotating part (together forming a magnetic circuit) is configured to generate a magnetic field, while the other of the stationary part and the rotating part comprises an electrical winding (in which the magnetic field induces an electric current). This enables to efficiently generate electricity.

[0037] In one embodiment, the generator is (completely) located outside the exhaust pipe. Preferably, the rotating part of the generator is mechanically coupled with the rotor shaft via a belt. This enables to make the size of the generator independent of the size of the exhaust pipe, thereby enabling to make the generator of a suitable size.

[0038] In an alternative embodiment, the generator is (completely) located inside the exhaust pipe, more preferably in an axial position. Preferably, the stationary part is firmly attached to the exhaust pipe (e.g. to the stator in an axial position), and the rotating part is firmly attached to the (shaft of the) rotor in a suitable manner. This reduces the footprint occupied by the generator and makes use of the exhaust pipe as a support structure for the generator.

[0039] In one embodiment, the machine comprises an additional turbine (and an additional generator), wherein, as mentioned above, the turbine is positioned upstream of the exhaust pipe (and / or downstream of the lower end of the first section), and wherein, as mentioned above, the additional turbine is positioned at the end of the second section. In other words, in order to obtain a higher percentage of energy that can be recovered, the machine can comprise two (or up to three) turbine-generator assemblies (each as described above) at the two (or three) positions described above.

[0040] Preferably, the machine comprises, in the upper part of the casing and in the case where it is housed inside the casing, a conveyor belt forming the cutting plane (for example, by means of the respective portion of belt currently arranged on top). Typically, this conveyor belt serves as a support for the fabric to be cut during the cutting process, and also as a means of moving the fabric to be cut or already cut before and after the cutting operation.

[0041] Preferably, the cutting plane is formed by the ends of a plurality of flexible elongated elements, which extend orthogonally to the cutting plane (for example, vertically). In this way, the cutting plane can support the fabric to be cut, while allowing the blade to penetrate with minimal or no damage to the cutting plane (possibly limited to a few vertical elements).

[0042] Preferably, the machine comprises a bridge spanning the cutting plane, positioned above the cutting plane and movable along the main extension direction of the machine, and a cutting head supported by the bridge and movable along the bridge. Preferably, the cutting head comprises a cutting device (for example, a blade). This enables the blade to be moved over the entire cutting plane. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 A side view of a machine for automatic cutting of fabric according to the present application is shown, partially and schematically.

[0044] Figure 2 A front view of the machine for automatic cutting of fabric shown in Figure 1

[0045] Figure 3 And Figure 4 A cross-sectional view of the respective parts of the machine shown in Figure 1 DETAILED DESCRIPTION

[0046] The features and advantages of the present application will be further clarified by the following detailed description of some embodiments thereof, given by way of example only, and in no way limitative, with reference to the accompanying drawings, purely by way of example and not to scale.

[0047] Figure 1 ​​A side view of a machine 1 for automatic cutting of cloth (not shown) or other flexible sheet material (e.g. leather, artificial leather, polymeric sheet material) is schematically depicted.

[0048] The machine has a main extension direction 50, coinciding with the direction of travel of the conveyor belt (indicated by dashed arrows).

[0049] Figure 2 A front view of the machine 1 is schematically shown, with the main extension direction 50 perpendicular to the plane of the drawing. For illustrative purposes, the figures show internal elements of the machine structure, which are normally covered by the machine structure itself or by a suitable housing.

[0050] The machine comprises a support structure 2 (only schematically shown) which partly forms a box 3 having an interior 4 and an open top face 8, and an external compartment 5 adjacent to the box along the main extension direction 50.

[0051] Preferably, the machine is provided, in the upper part of the box and in the case housed therein, with a conveyor belt 6, the top face (current surface) of which forms a cutting plane 7 designed to support the cloth during cutting. In alternative embodiments, the cutting plane can be of the static type.

[0052] Preferably, the conveyor belt 6 is covered by a plurality of flexible elongated elements (not shown) whose coplanar ends form the cutting plane. Thanks to a plurality of through holes made in the conveyor belt, the cutting plane (and the entire conveyor belt 6) is air-permeable.

[0053] The machine comprises a bridge suspended above the cutting plane and movable along the main extension direction 50 of the machine, and a cutting head supported by the bridge and movable transversely along the bridge. The cutting head comprises cutting means (e.g. a vertically oscillating blade). These components and their drive systems, electronics and control logic are not shown and further described here, as they can be of the known type.

[0054] The machine 1 comprises a suction system 9 configured to suck air from the interior 4 of the box 3, to create a pressure difference on opposite sides of the cutting plane 7. Typically, suction of air from the box creates a negative pressure below the cutting plane 7, so as to press the cloth against the cutting plane 7, effectively preventing the formation of wrinkles or creases during cutting of the cloth which can cause errors. The suction system 9 exemplarily comprises a fan 10 (only schematically shown, as it is per se widely known), housed in the compartment 5 and in fluid communication (via suitable ducts) with the interior 4 of the box (through openings 11 made in the walls of the box) and with the exhaust ducts described below.

[0055] The machine 1 comprises an exhaust duct 20, of circular cross-section, coupled with the suction system 9, for conveying the exhaust air flow coming from the suction system.

[0056] The machine 1 comprises a turbine 30 arranged upstream and / or along the exhaust duct 20, configured to extract energy from the exhaust air flow and to transform it into rotational mechanical energy, and an electric generator 40 mechanically coupled with the turbine 30, configured to transform the rotational mechanical energy of the turbine into electrical energy.

[0057] Preferably, the turbine 30 is an axial turbine, whose axis coincides with the local axis of the exhaust duct.

[0058] Preferably, the turbine is a single-stage turbine and comprises a stator 31 comprising a fixed frame rigidly attached to the exhaust duct and a stator element 32 rigidly attached to the frame, comprising a first plurality of radial vanes angularly distributed on a plane perpendicular to the axis. Upstream of the turbine (e.g. of the stator) a flow guide 34 (e.g. bell-shaped) can be included, and more preferably downstream a flow guide 35 (e.g. conical axial) can be included.

[0059] The turbine further comprises, downstream of the stator, a rotor 33 comprising a shaft rotatable about the axis and a second plurality of radial vanes fixed to the shaft, angularly distributed on a perpendicular plane.

[0060] The electric generator can be of known type.

[0061] Preferably, the exhaust duct comprises a first section 21, which is straight and horizontal, for example about 50 cm long, entirely contained within the compartment 5.

[0062] In one embodiment, the exhaust duct 20 comprises a second section 22, downstream of the first section, which is straight and vertical, extending upwards, for example about 150 cm long. Preferably, the exhaust duct comprises a curved connection section 23, which fluidically connects the first section and the second section. The second section 22 (and a substantial part of the curved connection section 23) extends outside the occupied space of the load-bearing structure 2. Exemplarily, the first section and the second section have a cross-sectional diameter of about 20 cm.

[0063] Preferably, the first section 21 and / or the second section 22 are entirely made of a respective flow silencer, which is only schematically shown and not further described, as it is per se widely known.

[0064] In one embodiment, not shown, the exhaust duct 20 consists only of the first section 21, optionally in combination with the curved connection section 23.

[0065] In one embodiment (e.g., as shown in solid lines in Figure 2 and as shown in Figure 3 ), the turbine 30 is located immediately upstream of the first section 21 of the exhaust pipe 20, between the fan of the suction system (immediately downstream of the fan) and the first section 21. Preferably, the corresponding generator 40 is located entirely outside the exhaust pipe, with the rotatable part of the generator being mechanically coupled to the rotor shaft of the turbine via a belt 41.

[0066] In one embodiment (as shown in dashed lines in Figure 2 ), the turbine 30 (with the corresponding generator, not shown, e.g., located outside the exhaust pipe) can be located downstream with respect to the exhaust air flow direction, at one end of the first section 21.

[0067] In another embodiment (e.g., as shown in solid lines in Figure 2 and as shown in Figure 4 ), the turbine 30 (and the generator 40) can be located at the upper end of the second section, downstream with respect to the exhaust air flow direction. Preferably, the generator 40 is located entirely inside the exhaust pipe 20, in an axial position in which the stationary part of the generator (e.g., via three mechanical arms) is rigidly attached in axial position to the frame of the stator 31, while the rotatable part is rigidly attached in coaxial manner to the shaft of the rotor 33. In Figure 2 , two turbines and their corresponding generators are shown in solid lines, while the other turbine is shown in dashed lines.

[0068] In a preferred embodiment of the present application (also for cost-effective trade-off considerations), it is envisaged that one and only one turbine and its corresponding generator are provided, and this single-stage turbine can be located in any of the positions described and shown herein, respectively. However, the present application also envisages embodiments involving the simultaneous presence of two (or three) different turbines, each with its corresponding generator, e.g., located in the positions described and shown herein, respectively.

Claims

1. Machine (1) for automatic cutting of fabric, comprising: - a box (3) having an open top face (8); - a cutting plane (7) located on the top face (8) of the box (3), the cutting plane (7) comprising a plurality of through openings; - a suction system (9) configured to suck air from the inside of the box (4) to generate a pressure difference on opposite faces of the cutting plane (7), the suction system generating an exhaust air flow; - a turbomachine (30) located downstream of the suction system (9) and configured to extract energy from the exhaust air flow and convert it into rotational mechanical energy; and - an electric generator (40) mechanically coupled with the turbomachine (30) and configured to convert the rotational mechanical energy of the turbomachine into electrical energy.

2. The machine according to claim 1, comprising an exhaust duct (20) in fluid communication with said suction system (9) for conveying said exhaust air flow; further comprising a load-bearing structure (2) at least partially constituting said cabinet (3) and a compartment (5) located outside said cabinet, said compartment (5) being arranged on one side of said cabinet (3) along a main direction of extension (50) of the machine, wherein, The suction system (9) is housed inside the load-bearing structure (2), the suction system (9) comprising at least one suction fan (10) housed inside the compartment (5) in fluid communication with the inside (4) of the box (3) and with the exhaust duct (20), wherein the exhaust duct (20) has a circular cross section, wherein the exhaust duct (20) comprises a first straight section (21) which is horizontal, having a length greater than or equal to 30 cm and less than or equal to 300 cm, and wherein the turbomachine is operationally coupled with the exhaust duct (20).

3. The machine of claim 2, wherein, The turbomachine (30) is located upstream of the exhaust duct (20), arranged between the suction system (9) and the exhaust duct (20), and wherein the turbomachine (30) and the electric generator (40) are housed inside the compartment (5).

4. The machine of claim 2 or 3, wherein, The exhaust duct (20) comprises a second section (22) located downstream of the first section (21), straight and vertically upwardly extending, wherein the second section (22) has a length greater than or equal to 100 cm and less than or equal to 400 cm, wherein the length of the second section (22) is greater than or equal to three times the diameter of the cross section of the second section, wherein the exhaust duct (20) comprises a curved connection section (23) connecting the first section (21) and the second section (22) in a flow-continuous manner, and wherein each of the first section and / or the second section comprises, or is entirely constituted by, an exhaust silencer.

5. The machine of claim 4, wherein, The turbomachine (30) and the electric generator (40) are arranged downstream of the upper end of the second section (22) with respect to the direction of the exhaust air flow, wherein the electric generator (40) is entirely located inside the exhaust duct (20) in an axial position, wherein the stationary part of the electric generator (40) is rigidly attached to the exhaust duct (20), and wherein the rotating part of the electric generator (40) is rigidly attached to the rotor (33) of the turbomachine (30) in a coaxial manner.

6. The machine of any one of the preceding claims, wherein, The turbine (30) is an axial turbine, the turbine axis coinciding with a local axis of the exhaust pipe (20), wherein the turbine is a reaction turbine, and wherein the turbine (30) is a single-stage turbine, comprising a stator fixed and rigidly attached to the exhaust pipe (20) and a rotor rotatable about the turbine axis.

7. The machine of claim 6, wherein, The stator comprises a fixed frame and a stator element rigidly attached to the frame, the stator element comprising a first plurality of fixed radial vanes angularly distributed in a plane perpendicular to the turbine axis, and wherein the rotor comprises a shaft rotatable about the turbine axis and a second plurality of radial vanes fixed to the shaft, the second plurality of radial vanes angularly distributed in the perpendicular plane, wherein the stator element is located upstream of the rotor with respect to the direction of the gas flow.

8. The machine of claim 7, wherein, The shape of the first and / or second plurality of vanes is configured to produce a substantially axial gas flow from the turbine output.

9. The machine of any one of the preceding claims, wherein, The generator (40) comprises a stationary part and a rotating part mechanically coupled to the rotor (33) of the turbine (30), wherein the stationary part and the rotating part form a magnetic circuit, wherein the generator (40) is entirely located outside the exhaust pipe (20), and wherein the rotating part is mechanically coupled to the rotor (33) of the turbine (30) by a belt (41).

10. The machine according to any one of the preceding claims, comprising, at an upper portion of the casing (3) and housed in the interior (4) of the casing (3), a conveyor belt (6) forming the cutting plane (7), and above the cutting plane (7) a gantry movable along a main extension direction (50) of the machine, and a cutting head supported by and movable along the gantry, wherein, The cutting head comprises a cutting device.

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