AUTOMATIC FABRIC CUTTING MACHINE

Abstract

Machine (100) for automatic fabric cutting, comprising: - a plurality of actuated components (11, 5, 6, 7, 4); - a plurality of actuation systems (30), in which each actuation system (30) is structured to actuate a respective actuated member (11, 5, 6, 7, 4) and comprises a respective control element (41, 42', 42'', 43, 44', 44'', 45) and a respective drive element (51, 52', 52'', 53, 54', 54'', 55) functionally connected, on the one hand, to the respective control element (41, 42', 42'', 43, 44', 44'', 45) and, on the other hand, to the respective actuated member (11, 5, 6, 7, 4); - a DC bus (31) connected to each control element (41, 42', 42'', 43, 44', 44'', 45) of each actuation system (11, 5, 6, 7, 4). See diagram: FIG. 2

Description

Title of the invention: AUTOMATIC FABRIC CUTTING MACHINE Technical field of the invention

[0001] The present invention relates to a machine for automatically cutting one or more superimposed pieces of fabric or other material into flexible sheets (for example, leather, synthetic leather, polymer sheets, etc.). State of the art

[0002] The term "pile" (in jargon "mattress" or "layer") designates a piece (in the case of a single layer) or several pieces of fabric superimposed, regardless of whether the piece is separated (for example by cutting) from the pieces located above and / or below, or whether it is continuous with them.

[0003] We know of automatic cutting machines for fabrics (or other flexible sheet material) which cut a stack of fabric pieces to typically obtain a plurality of fabric templates (each in number equal to the number of superimposed fabric layers) according to a pre-established cutting pattern (in the jargon "layout"), for example contained in a processing unit forming part of the machine. These templates are then used to manufacture various products, such as, for example, clothing, furniture or car interior coverings, etc.

[0004] Typically, cutting machines comprise a sliding conveyor belt, for moving the stack, which defines a cutting plane. These machines also comprise a cutting head, comprising a fabric cutting member, such as, for example, a blade (or a system of blades), movable along, and around, a direction perpendicular to the cutting plane. The cutting head is mounted on a movable bridge above the cutting plane and is movable over the entire cutting plane.

[0005] During the cutting operation, the fabric (or other flexible sheet material) may be spread over the cutting plane and secured thereto by applying a vacuum to the space beneath the cutting plane. The cutting operation may be performed stepwise (e.g., by discontinuous advancement of the conveyor belt on which the fabric is spread) or continuously (by continuous advancement of the conveyor belt). Summary of the Invention

[0006] For the purposes of the present invention, the term "actuated member" means any mechanical member of the automatic cutting machine subjected to physical movement in space (of the translation and / or rotation type), this movement comprising at least one acceleration phase and one braking phase, possibly interspersed and / or followed and / or preceded by a phase of uniform movement. Examples of actuated organs are the rotary suction fan (to create the vacuum), the cutting head, the moving bridge, the cutting organ, the conveyor belt.

[0007] In the field of automatic cutting of fabrics or other materials into flexible sheets, the Applicant raised the following points.

[0008] Generally, the cutting machine comprises a plurality of actuation systems structured to actuate the various actuated members of the machine according to a control logic. Each actuation system comprises, for example, a respective control element (for example, a servo-driver) and a motor element (for example, a servo-motor), the latter being connected, on the one hand, to the control element, and, on the other hand, to the respective actuated member (or, in other words, electrically interposed between the respective control element and the respective actuated member).

[0009] For example, the control elements are directly connected to the power supply network (e.g., the 400 V three-phase alternating current, AC, power network) and, during operation of the cutting machine, receive (e.g., from the processing unit of the machine) a control signal according to which they supply current to the motor element (usually, maintaining the alternating current, in English "alternated current" or "AC", i.e. the control element behaves like an AC / AC transformer) which produces energy for the actuation of the respective actuated member. During operation of the cutting machine, the motor element, via a suitable sensor, provides feedback to the control element in order to modulate the current supply (i.e. a closed feedback loop).

[0010] The Applicant observed that the control element alternately absorbs current from the supply network to supply current to the motor element, or receives current generated by the motor element.The current absorption occurs during the acceleration of the actuated member (for example, during the ignition phase or the increase in suction, and / or the phase of setting in motion one or more members among the cutting head, the moving bridge, the cutting member and the conveyor belt, and / or the acceleration of the cutting member in correspondence of the exit section of a curvilinear part before a rectilinear part of a template) and / or the maintenance of the state of movement of the actuated member by overcoming friction (for example, maintaining the suction flow rate at a determined value, and / or maintaining the cutting head, the moving bridge, the cutting member and / or the conveyor belt in a uniform movement), while the generation of current by the motor element occurs during the braking of the actuated member (for example, during the braking of the actuated member. example, during the phase of stopping or reducing the suction, and / or the phase of stopping the movement of one or more members among the cutting head, the mobile bridge, the cutting member and the conveyor belt, and / or the slowing down of the cutting member in correspondence with the entry into curved parts of the templates to be cut).

[0011] In known machines, the current generated by the motor element is sent by the control element to a braking resistor (generally dedicated to each actuation system and integrated in the respective control element) which dissipates the current by producing heat (Joule effect) which is dispersed into the environment. The Applicant has realized that, in known automatic cutting machines, the quantities of current dissipated in the braking resistors can be relatively large, which results in wasted energy (and related costs) and / or discomfort for the operator, for example due to the heat produced during the braking phases.

[0012] The Applicant therefore posed the problem of reducing energy consumption and / or inconvenience for the operator of the automatic cutting machine.

[0013] According to the Applicant, this problem is solved by an automatic fabric cutting machine according to the present invention.

[0014] According to one aspect, the invention relates to an automatic fabric cutting machine, comprising:

[0015] - a plurality of actuated members;

[0016] - a plurality of actuation systems, where each actuation system is structured to actuate a respective actuated member and comprises a respective control element and a respective motor element operatively connected, on the one hand, to the respective control element and, on the other hand, to the respective actuated member.

[0017] Preferably, said machine comprises a direct current bus connected to each control element of each actuation system.

[0018] The term "direct current bus" or "DC bus" means a power distribution system (or a power sub-network) in direct current (in English "direct current" or "DC") to said actuation systems of the machine.

[0019] The Applicant has realized that the introduction of a direct current bus into the automatic fabric cutting machine, connected to the control elements of the actuation systems, is particularly advantageous for reducing energy consumption in the automatic cutting cycles of fabric or any other flexible sheet material.

[0020] During a cutting cycle, the actuated members are subjected to continuous phases of acceleration, maintenance of the state of movement and deceleration / braking, these phases being able to be different between the various members at any time. For example, it may happen that one actuated member accelerates or moves with a uniform movement and that another actuated member brakes. The direct current bus connected to the actuation systems of the machine makes it possible to reuse (in real time and / or delayed) the electrical energy generated by the motor elements connected to the actuated members in the braking phase to supply (with current) the motor elements connected to the actuated members in the acceleration / uniform movement phase (which require energy).

[0021] In this way, according to the Applicant, it is possible, on the one hand, to reduce (or eliminate) the demand for absorption of electrical energy from the supply network (with obvious economic and environmental advantages) since the control elements absorb the energy distributed by the direct current bus, and, on the other hand, to reduce (or eliminate) the amount of current that must be dissipated by the braking resistors, with the consequent reduction (or elimination) of energy waste and / or heat produced.

[0022] The present invention therefore envisages the sharing and reuse of the electrical energy generated by the motor elements during the braking phases of the actuated members. This contrasts with what happens in the absence of a direct current bus, where each actuating system operates independently of the others with its control element which, if necessary, absorbs the electrical energy from the supply network (using the current from the supply network) and dissipates the current generated during the braking phases of the actuated member in a dedicated braking resistor.

[0023] The present invention, in one or more of the aforementioned aspects, may have one or more of the following preferred features.

[0024] Typically, said machine comprises a direct current electrical energy distributor connected, on the one hand, to said direct current bus and, on the other hand, to a power supply network (said distributor typically being an AC / DC transformer because the power supply network of industrial applications is typically in alternating current and the direct current bus operates in direct current mode).

[0025] Typically, each control element is a servo-driver and each motor element is a servo-motor•

[0026] Preferably, each control element is structured to supply the respective motor element with alternating current. For example, the control element acts as a DC / AC transformer so that the DC bus is compatible with normal AC-operated motors.

[0027] Preferably, said machine comprises a (single) capacitor (possibly consisting of a set of capacitors) connected (preferably in series) to said DC bus (said capacitor being an additional component compared to the capacitors normally integrated in the control elements to balance current peaks coming from the motor or the power supply). The Applicant has observed that, in certain circumstances, the current generated by a motor element connected to a first actuated member during the braking phase may be greater than the current absorbed at the same time by the motor elements connected to the actuated members which are in the acceleration phase. Consequently, in the absence of the above-mentioned capacitor, the excess current would be dissipated.The provision of a capacitor connected to the DC bus allows this possible excess current to be accumulated (like a battery), which can be used in the successive phases of the cutting operation (for example, by bringing the voltage at the DC bus terminals to the maximum value during the phases of high current absorption), with a further reduction in the demand for electrical energy (and therefore current) to be absorbed by the power supply network. Furthermore, in the event of a power failure on the network (for example, a general blackout), the capacitor allows a safe and / or controlled shutdown of the motors (for example, by limiting any voltage deviations).

[0028] In one embodiment, said machine comprises a (single) braking resistor (possibly composed of a set of braking resistors) connected (preferably in series) to said direct current bus, for example integrated in one of said control elements. In this way, by appropriately dimensioning the resistor, it is advantageously possible to share this (single) resistor between all the control elements and thus reduce the number (or capacity) of braking resistors integrated individually in the control elements, this providing advantages in terms of structural simplicity and / or reliability of the machine.

[0029] In one embodiment, said machine comprises a transistor (or a system of transistors) interposed between said direct current bus and said braking resistor. In this way, a switch is produced in a simple manner, allowing (or preventing) the passage of current from the direct current bus to the resistor.

[0030] Preferably, said machine comprises a cutting plane. Preferably, said machine comprises a suction system, comprising a fan and structured to generate a depression under said cutting plane (to keep said sheet of fabric pushed onto said cutting plane).

[0031] Preferably, said plurality of actuated members comprises said fan, for example integral with a motor shaft of the respective motor element.

[0032] The Applicant has realized that the fan motor element generates a high amount of energy during the braking phase (i.e., when stopping or decreasing the vacuum) of the fan (i.e., when slowing down the rotation of the fan), and that it is therefore advantageous to connect the fan actuation system to the direct current bus.

[0033] Preferably, said machine comprises a conveyor belt defining said cutting plane.

[0034] Preferably, said machine comprises a cutting head above said cutting plane. Preferably, said cutting head comprises a cutting member (for example, a blade).

[0035] Preferably, said machine comprises a handling bridge (supporting said cutting head and) movable along a first axis parallel to a main development direction of said cutting plane.

[0036] Preferably, said plurality of actuated members comprises said handling bridge. Preferably, the respective actuation system of the handling bridge comprises two respective drive elements (arranged on opposite parts of said cutting plane) comprising a respective drive shaft secured to a respective wheel sliding on a respective guide. The Applicant has realized that the handling bridge may have a relatively high mass and / or move at a relatively high speed while having to travel relatively large distances (the length defined by the main direction of development of the cutting plane), which results in a strong reduction in kinetic energy during the braking phases of the bridge. This results in the production of a relatively high amount of energy from the drive elements connected to the handling bridge.

[0037] Preferably, said plurality of actuated members comprises one or more of the following members: said cutting head, said conveyor belt and said cutting member. The Applicant has realized that connecting the actuation system of one or more of these actuated members to the direct current bus is advantageous in terms of energy savings.

[0038] Preferably, the respective actuation system of the cutting head is (integral to said bridge and) structured to move said cutting head along a second axis parallel to said cutting plane and perpendicular to a main development direction of said cutting plane (i.e., said first axis).

[0039] Preferably, the respective actuation system of the cutting member (is integral with said cutting head and) comprises two respective motor elements structured to move said cutting member respectively along a third axis perpendicular to said cutting plane, and around said third axis.

[0040] Preferably, the respective actuating system of the conveyor belt is structured to slide said conveyor belt along a direction of advancement (parallel to said main direction of development of said cutting plane), and comprises, for example, a respective motor element for rotating a roller. Brief description of the figures

[0041] [Fig.l] schematically and partially illustrates a perspective view of an automatic cutting machine according to the present invention;

[0042] [Fig. 2] illustrates in a purely conceptual manner, using a logic block diagram, an embodiment of the machine according to the present invention.

[0043] Detailed description of certain embodiments of the invention

[0044] The characteristics and advantages of the present invention will be clarified later by the following detailed description of certain embodiments of the present invention, presented by way of example and without limitation, with reference to the attached figures.

[0045] In [Fig.l], reference numeral 100 illustrates a machine for automatically cutting, typically, a piece of fabric, for example a cloth, or other material into flexible sheets (for example leather, synthetic leather, polymer sheets). To simplify the representation, a single piece is shown, but a stack of superimposed pieces of fabric may be provided.

[0046] The machine 100 comprises, by way of example, a cutting plane 3 (typically horizontal) capable of supporting the part 2, from which the templates 2' are cut. In [Fig.l], the templates 2' are shown with the cutting contours highlighted for illustration purposes only. In [Fig.l], the part 2 is illustrated in a rectangular plane, although the present invention finds application to any shape of plane of the part 2.

[0047] The machine 100 comprises a cutting head 6, located above the cutting plane 3, which comprises, by way of example, a cutting member 7, such as, for example, a blade (or a system of blades).

[0048] The machine 100 also comprises a handling bridge 5 supporting the cutting head 6.

[0049] By way of example, the machine 100 comprises a conveyor belt 4 (indicated only schematically and partially), the upper surface of which defines the cutting plane 3.

[0050] By way of example, the machine 100 comprises a suction system 8 structured to generate a depression under the cutting plane 3 (breathing air) in order to keep the part 2 pushed onto the cutting plane 3, to advantageously avoid the formation of folds or grimaces which would cause errors in the cutting of the templates 2'. By way of example, the suction system 8 comprises a fan 11 (illustrated purely schematically) and a hollow box 9 inside which the fan creates the depression.

[0051] The fan 11, the handling bridge 5, the cutting head 6, the cutting member 7 and the conveyor belt 4 are all actuated members.

[0052] As schematically shown in the figures, the machine 100 comprises a plurality of actuation systems 30 structured to actuate a respective actuated member. For example, the machine 100 comprises seven actuation systems 30.

[0053] Each actuation system 30 comprises a respective control element, for example a servo control, and a respective motor element, for example a servo motor (for example of rotary type). Each servo motor is operatively connected on the one hand to the respective control element and on the other hand (for example, via a respective motor shaft and, possibly, a respective transmission system) to the respective actuated member. By way of example, each actuation system 30 comprises a sensor (for example, an encoder) connected to the respective servo motor and structured to measure an output quantity (for example, the angular position) of the servo motor and provide feedback to the servo control on this output quantity of the servo motor for modulation of the current supply (i.e., the closed feedback loop).

[0054] By way of example, the respective actuation system 30 of the fan 11 comprises a single servomotor 51 and an associated servocontrol 41. The servomotor 51 comprises, for example, a respective motor shaft on which the fan 11 is fitted to rotate. In this way, the desired depression under the cutting plane 3 is obtained.

[0055] By way of example, the respective actuation system 30 of the handling bridge 5 comprises two respective motor elements 52' and 52" (arranged on opposite parts of the cutting plane 3) and two corresponding servocontrols 42' and 42". By way of example, the two motor elements 52' and 52" comprise a respective motor shaft secured to a respective wheel to rotate and slide it on a respective guide. In this way, the actuation system of the handling bridge 5 allows the forward and backward movement of the bridge 5 (and therefore of the cutting head 6) along a first horizontal axis (X) and parallel to a main development direction of the cutting plane 3. Advantageously, the actuation system of the handling bridge 5 comprises two separate actuation subsystems (and typically synchronized by a virtual axis) which allow a smooth, balanced and stable translation of the bridge 5 (and therefore of the cutting head 6) along the first axis (X).

[0056] By way of example, the respective actuation system of the cutting head 6 comprises a single servomotor 53 and a respective servocontrol 43. The servomotor 53 is, for example, integral with the bridge 5 and comprises, for example, (not shown) a respective motor shaft integral with a respective roller which rotates a belt to which the cutting head is fixed. In this way, it is possible to move the cutting head 6 back and forth along a second axis (Y) parallel to the cutting plane 3 and perpendicular to the first axis (X).

[0057] In this way, the cutting head 6 can be moved globally over the entire cutting plane 3.

[0058] By way of example, the respective actuation system of the cutting member 7 comprises two respective motor elements 54' and 54" and two respective servocontrols 44' and 44". By way of example, the two servomotors 54' and 54" are integral with the cutting head 7 and comprise a respective motor shaft for moving the cutting member up and down (for example, with a high-frequency alternating movement) along a third axis (Z) perpendicular to the cutting plane 3. By way of example, the motor shaft of the servomotor 54" engages with the cutting member 7 to rotate it around the third axis.

[0059] By way of example, the respective actuation system of the conveyor belt 4 comprises a single servomotor 55 and an associated servocontrol 45. By way of example, the servomotor 55 comprises (not shown) a respective motor shaft and a roller secured to the respective motor shaft of the servomotor 55, so as to rotate the roller to slide the conveyor belt 4 along a direction of advancement 200 (parallel to the main development direction of the cutting plane 3), separately or continuously depending on the requirements of the process.

[0060] In order to allow the machine 100 to operate correctly, the latter is connected to a power supply network 70, for example the power supply network with a network voltage of 400 V alternating current.

[0061] Advantageously, the machine 100 comprises a direct current bus 31 connected to each servo control 41-45 of the actuation systems 30. The direct current bus 31 creates a DC sub-network isolated from the power supply network 70. The current bus is created by means of an appropriate electrical connection architecture.

[0062] As mentioned above, during operation of the machine 100, the direct current bus 31 connected to the servocontrols 41-45 makes it possible to reuse the electrical energy generated by the servomotors 51-55 connected to the members actuated in the braking phase, for the power supply of the servomotors connected to the actuated organs in the acceleration / uniform motion phase (which require energy). In fact, the bus 31 is able to use the energy produced during the braking phase of the actuated organs in order to balance the voltage drop due to the absorption of energy by the actuated organs during the acceleration phase and / or the maintenance of the motion state. In other words, the bus 31 is able to maintain the voltage at its terminals always at the same value (for example, 750 VDC), thus allowing a lower energy demand from the 400 VAC network.

[0063] For example, during the entire cutting operation, the servomotor 51 of the fan 11 is controlled on the basis of the power required at each instant and therefore absorbs or generates electrical energy as required. Similarly, the handling bridge 5, and / or the cutting head 6 and / or the cutting member 7, are subjected to alternating phases of acceleration and braking, during which the respective servomotors 52', 52", 53, 54', 54" absorb and generate electrical energy respectively. The electrical energy generated is redistributed by the bus 31 to power the servomotors which absorb current.

[0064] The machine 100 also comprises, for example, a direct current electrical energy distributor 34 connected, on the one hand, to the direct current bus 31 and, on the other hand, to the power supply network 70. This distributor 34 makes it possible to take electrical energy from the power supply network 70 and to convert the network voltage (in alternating current) into a voltage, for example 750 V, in direct current, adapted to the operation of the direct current bus 31.

[0065] In one embodiment, a single device integrates both the AC / DC converter and a first control element (closest to the network 70), where the remaining control elements are connected in parallel to the first control element by means of the DC bus. For example, this single integrated device may be the model XCD2-W2323ARN and the remaining control elements may be the models XMD2-W1616ANN and / or XMD2-W1010ANN, all marketed by Bosch Rexroth AG.

[0066] Typically, servomotors 51-55 operate on alternating current, and therefore servodrives 41-45 may be structured to act as a DC / AC transformer to make the DC bus compatible with servomotors 51-55.

[0067] By way of example, the machine 100 comprises a single capacitor 35 connected, for example in series, to the direct current bus 31. In fact, the Applicant has advantageously realized that by enriching the bus 31 with a capacitor (or alternatively, or in combination, with intelligent power supply modules), it is possible to create a redundancy of components capable of storing energy in order to further limit energy waste.

[0068] By way of example, the machine 100 comprises a single braking resistor 32 connected, for example in series, to the direct current bus 31 and a transistor 33 (for example of the MOSFET type), for example, interposed between the direct current bus 31 and the resistor 32. This resistor 32 makes it possible to dissipate any excess electrical energy, for example beyond the capacity of the bus 31 and / or the capacitor 35 and / or beyond the demand of the actuated members in the acceleration phase. In addition, the resistor 32 makes it possible to eliminate the braking resistors integrated individually in the actuation systems 30, this providing advantages in terms of structural simplicity and / or reliability of the machine.

Claims

Claims

1. Machine (100) for automatic cutting of fabric, comprising: - a plurality of actuated members (11, 5, 6, 7, 4); - a plurality of actuation systems (30), wherein each actuation system (30) is structured to actuate a respective actuated member (11, 5, 6, 7, 4) and comprises a respective control element (41, 42', 42”, 43, 44', 44”, 45) and a respective motor element (51, 52', 52”, 53, 54', 54”, 55) operatively connected, on the one hand, to the respective control element (41, 42', 42”, 43, 44', 44”, 45) and, on the other hand, to the respective actuated member (11, 5, 6, 7, 4); and - a direct current bus (31) connected to each control element (41, 42', 42", 43, 44', 44", 45) of each actuation system (11, 5, 6, 7, 4).

2. Machine (100) according to claim 1, comprising a direct current electrical energy distributor (34) connected, on the one hand, to said direct current bus (31) and, on the other hand, to a power supply network (70).

3. Machine (100) according to any one of the preceding claims, wherein each control element (41, 42', 42", 43, 44', 44", 45) is a servo control and each motor element (51, 52', 52", 53, 54', 54", 55) is a servo motor.

4. A machine (100) according to any preceding claim, wherein each control element (41, 42', 42", 43, 44', 44", 45) is structured to supply the respective motor element (51, 52', 52", 53, 54', 54", 55) with alternating current.

5. Machine (100) according to any one of the preceding claims, comprising a capacitor (35) connected to said direct current bus (31).

6. The machine (100) of claim 5, wherein said capacitor (35) is connected in series with said direct current bus (31).

7. Machine (100) according to any one of the preceding claims, comprising a braking resistor (32) connected to said direct current bus (31).

8. A machine (100) according to claim 7, wherein said braking resistor (32) is connected in series with said direct current bus (31).

9. Machine (100) according to claim 7 or 8, comprising a transistor (33) interposed between said direct current bus (31) and said braking resistor (32).

10. Machine (100) according to any one of the preceding claims, comprising a suction system (8) comprising a fan (11) and structured to generate a depression under a cutting plane (3).

11. A machine (100) according to claim 10, wherein said plurality of actuated members (11, 5, 6, 7, 4) comprises said fan (11).

12. Machine (100) according to any one of the preceding claims, comprising a conveyor belt (4) defining a cutting plane (3).

13. A machine (100) according to claim 12, wherein said plurality of actuated members (11, 5, 6, 7, 4) comprises said conveyor belt (4).

14. Machine (100) according to claim 12 or 13, wherein said conveyor belt (4) actuating system is structured to slide said conveyor belt (4) along a direction of advancement (200).

15. Machine (100) according to any one of the preceding claims, comprising a cutting head (6) located above a cutting plane, wherein said cutting head (6) comprises a cutting member (7).

16. Machine (100) according to claim 15, wherein said plurality of actuated members (11, 5, 6, 7, 4) comprises said cutting head (6) and / or said cutting member.

17. Machine (100) according to claim 15 or 16, wherein said cutting head (6) actuation system is structured to move said cutting head (6) along a second axis (Y) parallel to a cutting plane (3) and perpendicular to a main development direction of said cutting plane (3).

18. Machine (100) according to claim 15 or 16 or 17, wherein the respective actuation system of the cutting member (7) comprises two respective motor elements (54', 54") structured to moving said cutting member (7) respectively along a third axis (Z) perpendicular to a cutting plane (3), and around said third axis (Z).

19. Machine (100) according to any one of the preceding claims, comprising a handling bridge (5) movable along a first axis (X) parallel to a main development direction of a cutting plane (3).

20. Machine (100) according to claim 19, wherein said plurality of actuated members (11, 5, 6, 7, 4) comprises said handling bridge (5).

21. Machine (100) according to claim 19 or 20, wherein the respective actuation system of the handling bridge (5) comprises two respective motor elements (52', 52") comprising a respective motor shaft secured to a respective wheel sliding on a respective guide.

Images