Machine for handling limp materials, especially textile articles

Abstract

The present invention relates to a machine (1) for handling a limp material (3), the machine (1) comprising at least first and second gripping devices (10) adapted to simultaneously grip the same piece of the limp material (3), at least one of the gripping devices (10) being connected to a drive system (5) adapted to displace the gripping devices (10) relative to each other, one of the gripping devices (10) being a manipulator (10) having a displacement mechanism (20) adapted to actively displace the limp material (3) in a direction generally in a plane in which the limp material (3) is held in the manipulator (10), the machine (1) further comprising at least one sensor (30) adapted to detect the limp material (3) and / or an area of ​​interest.

Description

[Technical field]

[0001] The present invention relates to a machine for handling limp material, the machine comprising at least first and second gripping devices adapted to simultaneously grip the same piece of limp material. [Background technology]

[0002] A challenge associated with handling limp material, such as textile articles, is that the limp material does not have a defined shape. As a simple example, a tablecloth may have an unfolded rectangular shape, or may exist in the form of a fairly small, crumpled bundle. Attempts to handle limp material in an automated manner require the limp material to be forced into a predetermined shape, or at least to clearly identify certain points of the limp material, such as edges.

[0003] The term "limp material" in this specification refers to textile articles, especially products for human living such as clothing, and industrial products such as panels, covers or textile mats. It further includes paper, sheets of foil material, and knitted fabrics. These examples are not exhaustive.

[0004] An example of a machine for handling limp material can be found in WO 2021 / 001039. The machine includes two grippers that engage the textile article at two points apart from each other. The grippers can give the textile article a predetermined shape for further processing. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to improve the handling capabilities of machines used to handle limp material. [Means for solving the problem]

[0006] To this end, the invention provides a machine for handling limp material, the machine comprising at least a first and a second gripping device adapted to grip the same piece of limp material simultaneously, at least one of the gripping devices being connected to a drive system adapted to displace the gripping devices relative to each other, one of the gripping devices being a manipulator having a displacement mechanism adapted to actively displace the limp material in a direction that is generally in a plane in which the limp material is held in the manipulator, the machine further comprising at least one sensor adapted to detect the limp material and / or an area of ​​interest of the limp material. The invention is based on the idea of ​​adding an additional function to the grippers known from the prior art. In the prior art, the limp material engaged by the gripper can be made to slide in the gripper when a sufficient traction force is applied to the limp material. The displacement mechanism provided in the manipulator according to the invention makes it possible to control the sliding movement of the limp material in the manipulator. In particular, the displacement mechanism makes it possible to actively move the textile article relative to the manipulator. It is thus possible to slide the limp material to a specific position relative to the manipulator. In an improved embodiment, it is possible to make the manipulator follow the non-linear contour of the limp material in order to reach a position or specific point in the limp material which is beneficial for subsequent handling.

[0007] Preferably, the manipulator comprises a base and a pressing part which are displaceable relative to each other, the displacement mechanism being provided at the base. The base and pressing part being displaceable relative to each other allows the limp material to be loaded into the manipulator and clamped therein with a predetermined and / or controllable force. It is also conceivable that the base and pressing part are displaceable relative to each other by a predetermined and / or controllable distance, which makes force measurement unnecessary.

[0008] In a preferred embodiment, the displacement mechanism includes at least one displacement wheel arranged to engage the limp material, the wheel being particularly suited to generating a sliding movement of the limp material relative to the base, with the degree of sliding movement being readily controllable by the amount of rotation of the wheel.

[0009] In a particularly simple embodiment, the displacement wheel is an omni-wheel, which allows the limp material to slide against the base in a direction tangential to the omni-wheel while at the same time allowing low friction displacement in a direction parallel to the axis of rotation of the omni-wheel.

[0010] In order to increase the friction between the wheel and the limp material, the pressing part may be provided with a guide groove associated with the displacement wheel.

[0011] In one embodiment of the present invention, a receiving space is provided between the base and the pressing part, the receiving space is adapted to receive an edge of the limp material, and the sensor is arranged to detect the position of the edge in the receiving space. Assuming that the limp material having an edge could be arranged in the receiving space, the position of the edge in the receiving space is particularly suitable for controlling the sliding displacement of the limp material by the wheel.

[0012] The sensor can be made of separate sensing elements spaced apart from each other. The distance between the separate sensing elements can be considered as a tolerance range within which the edge of the limp material should be. The separate sensing elements make it possible to detect whether the edge is between the sensing elements or not. If not, the limp material can be slid inwards or outwards by appropriately rotating the displacement wheel until the edge returns to the desired position.

[0013] In one embodiment of the present invention, a pair of displacement wheels is provided. The use of a pair of displacement wheels allows for better control of the displacement of the limp material relative to the manipulator.

[0014] The pressing section may include a pair of pressing wheels and pressing elements that are independently movable relative to the displacement wheel, in particular in a direction perpendicular to the plane in which the limp material is held between the displacement wheels. The force with which the limp material is clamped between the displacement wheel and the pressing wheel may be controlled by the displacement of the pressing wheel. Furthermore, the pressing wheel and pressing element may be retracted to allow loading and unloading of the limp material.

[0015] In one embodiment, the base can rotate about an axis perpendicular to the axis of rotation of the displacement wheel, allowing the direction of displacement of the limp material relative to the base to coincide with the direction in which the contour or edge of the limp material extends.

[0016] Preferably, the sensor is configured to detect the presence of the limp material within a detection area extending circumferentially around the base, thereby providing the information necessary to slide the limp material in a desired direction relative to the base.

[0017] Preferably, the sensor is formed from a plurality of separate sensing elements arranged circumferentially around the base. It is not necessary for the sensor to continuously monitor the circumference of the base, rather it is sufficient to obtain information about which sectors of the circumference the limp material is present in and which are not.

[0018] The sensor may also be formed from a camera system associated with an image recognition system adapted to evaluate the information provided by the camera and to extract therefrom the location of the limp material.

[0019] Instead of using wheels to achieve displacement of the limp material, any other element suitable for sliding the limp material relative to the base can be used, examples are belts, translatable pusher elements, reciprocating yaw, etc.

[0020] In one embodiment, the machine has two manipulators with at least one displacement wheel. The use of two manipulators makes it possible to handle limp material with more complex contours and to displace the limp material relative to the manipulators to reach a predetermined point on the limp material.

[0021] In one embodiment, the drive system includes a linear drive to which the grippers are attached, the linear drive adapted to displace the grippers from a loaded position in which the grippers are close to each other to a position in which the grippers are spaced apart from each other and vice versa. The linear drive is a mechanically simple and reliable system for obtaining the desired displacement of the grippers relative to each other.

[0022] In an alternative embodiment, the drive system comprises two robotic arms, each of which is provided with one gripping device, the robotic arms being adapted to displace the gripping devices from a loading position in which they are close to each other to a remote position in which they are spaced apart from each other and vice versa. The robotic arms assist the gripping devices in processing limp material having more complex contours, in particular contours that are not only composed of several straight sections. [Brief description of the drawings]

[0023] The invention will now be described with reference to embodiments illustrated in the accompanying drawings, in which:

[0024] [Figure 1] FIG. 1 shows a first embodiment of a machine having two gripping devices in a loading position. [Diagram 2] FIG. 2 shows the machine of FIG. 1 with the two gripping devices in a spaced apart position. [Diagram 3] FIG. 2 shows a second embodiment of a machine according to the invention with two gripping devices in the loading position. [Figure 4] FIG. 4 shows the machine of FIG. 3 with the gripping device in a spaced position. [Diagram 5] 1 is a schematic cross-sectional view of a manipulator according to a first embodiment. [Figure 6] FIG. 6 is a perspective view of the manipulator of FIG. 5. [Figure 7] FIG. 11 is a side view of a manipulator according to a second embodiment. [Figure 8] FIG. 8 is a perspective view of the manipulator of FIG. 7. [Figure 9] FIG. 8 is a second perspective view of the manipulator of FIG. 7, the manipulator being in a first working position. [Figure 10] FIG. 8 shows the manipulator of FIG. 7 in a second working position. [Figure 11] FIG. 8 is a schematic top view of the base of the manipulator of FIG. 7. [Figure 12] 5A-5D show diagrammatically a machine according to a third embodiment in two different positions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] In figures 1 and 2 a machine 1 for handling limp material 3 is shown diagrammatically. By way of example, the limp material is in the following a textile article. It is noted that the invention is applicable to any kind of limp material.

[0026] The machine 1 comprises two gripping devices 10, each adapted to receive and hold a textile article 3 currently being handled.

[0027] The two gripping devices 10 are attached to a drive system 5 that allows the gripping devices 10 to be displaced relative to one another. As can be seen by comparing Figures 1 and 2, the drive system 5 makes it possible to displace the gripping devices 10 from a loading position shown in Figure 1, in which the gripping devices 10 are arranged close to or in contact with one another, to a position shown in Figure 2, in which the gripping devices 10 are separated from one another.

[0028] The drive system 5 can in particular be a linear drive making it possible to displace the two gripping devices away from each other in the direction of the arrow A, or vice versa. Of course, it is also possible to arrange the gripping devices stationary and to displace only the other gripping device 10.

[0029] In the loading position, the textile article 3 is loaded onto the gripping devices 10. By displacing the gripping devices 10 away from each other, the textile article is stretched and tensioned, with the edges of the textile article 3 received within the gripping devices 10 sliding through the gripping devices.

[0030] In figures 3 and 4 a second embodiment of a machine 1 for handling textile articles 3 is shown.

[0031] The difference between the first embodiment and the second embodiment is that in the second embodiment, a robot arm 7 is used as a drive system for moving the gripping devices 10 relative to one another.

[0032] A variation of the second embodiment may use one gripping device 10 that is stationarily mounted, and only the second gripping device 10 may be displaced relative to the stationary gripping device.

[0033] In yet another variation, one of the gripping devices 10 can be used as a simple gripper that simply clamps a corner of a textile article placed thereon, while the other gripper 10 is displaced away from the first gripper and follows the contour of the edge.

[0034] A first embodiment of a gripping device 10 is shown in Figures 5 and 6. The gripping device of Figures 5 and 6 is referred to as a manipulator because it is capable of actively sliding a textile article relative to the gripping device (in addition to allowing passive sliding motion in response to displacement of the gripping devices relative to one another).

[0035] The manipulator 10 has a base 12 and a pressing portion 14. The base 12 and the pressing portion 14 are displaceable relative to each other between a receiving position in which they are spaced apart from each other and a clamping position in which they are close to each other, as indicated by arrows D, and the textile article 3 is clamped in the gap between the base 12 and the pressing portion 14.

[0036] The gripping device 10 is provided with a displacement mechanism 20 adapted to actively displace the textile article in a direction that is substantially in the plane in which the textile article is held in the manipulator, which, looking at Figure 5, is perpendicular to the plane of the drawing and extends horizontally.

[0037] The displacement mechanism 20 here includes a displacement wheel 22 rotatably mounted on the base 12. As can be seen in Fig. 6, a part of the displacement wheel 22 protrudes above the surface of the base 12 facing the pressing part 14. In the position of the base 12 relative to the pressing part 14 shown in Figs. 5 and 6, the protruding part of the displacement wheel 22 engages with a guide groove 24 formed in the pressing part 14.

[0038] The displacement wheel 22 can be actively rotated in either direction by a motor element 26, shown diagrammatically in FIG.

[0039] The gap between the base 12 and the pressing part 14 inside the displacement wheel 22 forms an accommodation space 28 for the edge of the textile article 3 received between the base 12 and the pressing part 14 (see FIG. 5 where the textile article 3 is shown diagrammatically).

[0040] The gripping device 10 is associated with a sensor 30 adapted to detect the position of the edge of the textile article 3 .

[0041] In the embodiment shown in FIG. 5, the sensor 30 is formed from separate sensing elements spaced apart from one another in the direction of arrow T which indicates the tolerance band in which the edge of the textile article is assumed to lie.

[0042] The detection element 32 may for example be formed in conjunction with a light barrier so as to be able to detect the presence of the textile article 3 .

[0043] The space inside the displacement wheels 22 is called the receiving space for the edge of the textile article 3, but the space can receive any part of the textile article 3, for example the central part, when in a first step the textile article is "thrown" onto the base 12 with the presser 14 and the base 12 separated to receive the textile article 3. After placing the textile article on the base 12, the textile article is manipulated until its edge is detected by the sensor 30.

[0044] Here, the displacement wheel 22 is formed as an omni-wheel, so that by rotating the displacement wheel 22 in a clockwise or counterclockwise direction relative to Fig. 5 it is possible to displace the textile article 3 in the direction of the arrow T, and at the same time it is possible to displace the textile article 3 in a direction perpendicular to the plane of Fig. 5, for example by increasing the distance between the two gripping devices 10.

[0045] With reference to FIG. 2, assuming that each of the gripping devices 10 is provided with a displacement mechanism 20, the edge of the textile article 3 can be controlled by appropriately controlling the displacement mechanism so as to displace the portion of the textile article gripped in the gripping device in the direction of the arrow T during the step of releasing the gripping devices 10. The degree of displacement of the textile article 3 can be very easily controlled by a sensor 30 detecting the position of the edge of the textile article 3. As can be seen in FIG. 5, the information that both pairs of detection elements 32 are blocked by the textile article 3 can be interpreted as the textile article 3 being too far inward in the receiving space 28, resulting in a counterclockwise movement of the displacement wheel 22 until the inner detection element 32 no longer detects the presence of the textile article. The information that both detection elements 32 do not detect the textile article can be interpreted as the textile article is not far enough in the receiving space 28, resulting in a clockwise rotation of the displacement wheel 22 until the outer detection element 32 detects the presence of the textile article again.

[0046] A second embodiment of a gripping device 10 formed as a manipulator is shown in figures 7 to 10. For components known from the first embodiment the same reference numbers are used and reference is made to the above comments.

[0047] Whereas the first embodiment uses a gripping device in the form of two jaws cooperating with each other, the second embodiment has a post- or column-like base 12 with which a pressing part 14 cooperates. A further difference between the first and second embodiment is that the second embodiment uses two displacement wheels 22 instead of a single displacement wheel.

[0048] The displacement wheels 22 are rotatably mounted in the base 12. They can be actively driven by a motor, not shown here. The motor is adapted to rotate both displacement wheels 22 in the same direction and at the same rotational speed. By way of example, both displacement wheels can be fixedly connected to one and the same drive shaft.

[0049] To increase the friction with the textile article to be displaced, the displacement wheels 23 can include a suitable configuration on their circumference. As shown in Figures 7 to 10, the displacement wheels 22 here have a number of teeth.

[0050] As an alternative to teeth, the displacement wheel 22 may be provided with a rubber coating or any other surface that promotes friction between the displacement wheel and the textile article.

[0051] The pressing unit 14 includes two pressing wheels 23 arranged to cooperate with the displacement wheels 22. The pressing wheels 23 have a sawtooth outer periphery.

[0052] The pressure part 14 further comprises a pressure element 25 which can be displaced towards and away from the base 12 independently of the pressure wheel 23. The pressure element 25 here has a spherical surface adapted to cooperate with a guiding recess 27 of the base 12 (see FIG. 9 ).

[0053] The gripping device 10 shown in Figures 7 to 10 is configured to receive and clamp a textile article in a plane P, which is shown diagrammatically in Figure 7. By rotating the displacement wheel 22, the textile article 3 can be displaced in this plane P in a direction tangential to the circumference of the displacement wheel 22. In other words, the textile article 3 can be displaced in a direction perpendicular to the plane of the drawing, as viewed in Figure 7.

[0054] To load the textile article 3 into the gripping device 10, the presser 14 and the presser element 25 are retracted. Once the textile article is placed on the base 12, the presser 14 is lowered to the position shown in Figure 9. In this position, the textile article is clamped between the displacement wheel 22 and the pressure wheel 23. Rotation of the displacement wheel 22 therefore results in a displacement of the textile article relative to the base 12.

[0055] If the orientation of the textile article relative to the base 12 is changed, the pressing element 25 is lowered to clamp the textile article between the pressing part and the guide recess 27 while the pressing part 14 is moved upwards (see FIG. 10). In this state, the textile article can be rotated relative to the base 12 by overcoming the (reduced) frictional force between the pressing element 25 and the guide recess 27. Once the textile article is brought to the desired position, the pressing part 14 is lowered to clamp the textile article again between the displacement wheel and the pressing wheel, and the pressing element 25 can be retracted.

[0056] Changing the orientation of the textile article, for example by displacing the textile article in different directions relative to the base 12, makes it possible to "navigate" to a desired point on the textile article.

[0057] FIG. 11 shows a schematic view of the base 12 and the textile article 3, where for greater clarity the pressing part 14 is not shown.

[0058] Shown on the base 12 are several of a plurality of sensing elements 32 which collectively form a sensor. The sensing elements 32 are arranged circumferentially around the base 12.

[0059] As with the first embodiment, the sensor 30 is formed from a plurality of separate sensing elements 32. These are equally spaced around the base 12.

[0060] The separate detection elements 32 make it possible to detect the position and orientation of the textile article 3, in particular the position of the edge E of the textile article 3. Assuming that the textile article 3 is randomly placed on the base 12 at the start of the handling process, all detection elements 32 are covered. By rotating the displacement wheel 22, the textile article is displaced relative to the base 12 in the direction indicated by the arrow 50 in FIG.

[0061] At some point, the textile article 3 is displaced until some of the sensing elements 32 are exposed. This condition is illustrated in Figure 11, where four of the sensing elements 32 are shown exposed. Assuming edge E is a straight line, the orientation of edge E can be determined to be perpendicular to a line 52 that forms the center of a sector 54 defined by the exposed sensing elements 32.

[0062] It can be seen that the more detection elements provided around the base 12, the higher the detection accuracy.

[0063] Once the orientation of edge E has been determined and it is further intended to displace the textile article 3 along edge E, the direction of displacement of the textile article 3 must be made parallel to edge E. In the situation shown in Figure 11, these two directions are not yet parallel. The actual displacement direction is indicated by arrow 50, but the direction of edge E (indicated by arrow 56) is not parallel to direction 50.

[0064] In a first step, the pressing element 25 is lowered and then the pressing portion 14 is retracted to press the textile article 3 against the base 12. Next, one of the textile articles 3 is rotated in the direction of arrow 58 relative to the base 12 until the orientation of the edge E is parallel to the displacement direction 50. This can be achieved by a second gripping device engaging the textile article 3. Alternatively, the textile article 3 is held stationary and the base 12 is rotated in the direction of arrow 60 relative to the textile article 3.

[0065] Once the orientation of edge E of the textile article 3 is parallel to the displacement direction 50 defined by the displacement wheel 22 of the base 12, the textile article 3 can be further displaced relative to the base 12 while the position of edge E relative to the base 12 is continuously monitored by the sensor 30. A change in the sector of the sensing element 32 that is not covered by the textile article 3 indicates that the textile article 3 is displaced in a direction that is not parallel to its edge E. Further intervention is therefore required.

[0066] Another way of changing the orientation of the textile article 3 relative to the base 12 is to use a drive adapted to rotate the two displacement wheels 22 in opposite directions or independently of each other so that the textile article 3 can rotate around an axis located between the two displacement wheels 22 or around an axis located outside the two displacement wheels.

[0067] To rotate the textile article 3, the displacement wheels 3 are driven in the required manner (eg opposite to each other). In this embodiment, the pressure element 25 can be omitted.

[0068] In yet another variant, the displacement wheel 12 can be formed as an omni-wheel, allowing a displacement of the textile article 3 obliquely or transversely to the advancement direction of the textile article defined by the rotation of the displacement wheel.

[0069] In yet a further embodiment, the base 12 comprises a set of displacement wheels 22 of the type shown in Figures 7 to 10 (driving the textile article in a direction defined by the orientation of the rotation axes of the displacement wheels 22) and an omni-wheel (or two omni-wheels) allowing a lateral displacement of the textile article. The different types of displacement wheels are mounted on the base 14 which is movable between a retracted position and an active position, such that one type of displacement wheel is in an active position and the other type is in a retracted position. This makes it possible to change between two different operating modes, one having a predefined displacement direction of the textile article 3 and the other having the possibility of a lateral displacement of the textile article 3 in addition to the displacement caused by the rotation of the omni-wheel(s).

[0070] Figure 12 shows an embodiment of the machine in which two of the manipulators shown in Figures 7 to 10 are used, here attached to a robot arm 70 each having six degrees of freedom. The robot arm constitutes the drive system 5.

[0071] The starting position is shown by a continuous line on the left side of Fig. 12. Both gripping devices 10 are positioned close to each other and the textile article is gripped between the two gripping devices 10. After the textile article is loaded into the gripping devices 10, the gripping devices 10 are moved away from each other to straighten the textile article. At the same time, the textile article is displaced relative to the base 12 until an edge of the textile article is detected. After that, the textile article is displaced relative to the base 12 along the detected edge until a predetermined point on the textile article is reached.

[0072] When the gripping device 10 is mounted on a robotic arm 70, complex movements are possible that enable the manipulator to follow the complex contours and edges of the textile article.

[0073] Generally speaking, the machine according to the present invention can be thought of as a linear positioning device for spreading and placing limp material by first reaching a straight boundary segment of a textile article and then performing a linear edge trace while stopping upon corner recognition, using two actively controlled manipulators and sensors.

[0074] Although this example shows two gripping devices or manipulators working together, it is possible to use more than two gripping devices to process more complex textile articles or to increase processing speed.

Claims

1. A machine (1) for handling limp material (3), in particular textile articles, said machine (1) comprising at least first and second gripping devices (10) adapted to grip the same piece of limp material (3) simultaneously, at least one of said gripping devices (10) being connected to a drive system (5) adapted to displace said gripping devices (10) relative to one another, one of said gripping devices (10) being a manipulator (10) having a displacement mechanism (20) adapted to actively displace said limp material (3) in a direction generally lying in a plane in which said limp material (3) is held in said manipulator (10), and further comprising at least one sensor (30) adapted to detect said limp material (3) and / or an area of ​​interest.

2. 2. The machine according to claim 1, wherein the manipulator (10) comprises a base (12) and a pressing part (14) displaceable relative to each other, the displacement mechanism (20) being provided on the base (12).

3. 3. The machine of claim 2, wherein the displacement mechanism (20) comprises at least one displacement wheel (22) arranged to engage the limp material (3).

4. 4. The machine of claim 3, wherein the displacement wheel (22) is an omni-wheel.

5. 5. A machine according to claim 3 or 4, characterized in that a guide groove (24) associated with the displacement wheel (22) is provided in the pressing part (14).

6. 6. A machine as claimed in any one of claims 3 to 5, wherein a receiving space (28) is provided between the base (12) and the pressing part (14), the receiving space (28) being adapted to receive an edge (E) of the limp material (3), and the sensor (30) being arranged to detect the position of the edge (E) within the receiving space (28).

7. 7. The machine of claim 6, wherein the sensor (30) is formed from separate sensing elements (32) spaced apart from one another.

8. A machine as claimed in claim 3 or 4, characterized in that a pair of displacement wheels (22) is provided.

9. 9. The machine according to claim 8, wherein the pressing part (14) comprises a pair of a pressing wheel (23) and a pressing element (25), the pressing wheel (23) and the pressing element (25) being movable independently of each other with respect to the displacement wheel (22), in particular in a direction perpendicular to the plane in which the limp material (3) is held between the displacement wheel (22) and the pressing wheel (23).

10. 10. A machine as claimed in claim 8 or 9, in which drives for the displacement wheels are provided adapted to rotate the wheels independently or in opposite directions to one another.

11. 11. A machine as claimed in any one of claims 8 to 10, wherein the sensor (30) is configured to detect the presence of the limp material (3) within a detection area extending circumferentially around the base (12).

12. The machine of claim 11, wherein the sensor (30) is formed from a plurality of separate sensing elements (32) circumferentially disposed about the base (12).

13. 13. A machine according to any one of the preceding claims, wherein the base (12) and / or the pressing part (14) are rotatable about an axis perpendicular to the axis of rotation of the displacement wheel (23).

14. A machine according to any one of the preceding claims, wherein two manipulators (10) are provided.

15. 15. A machine according to any one of claims 1 to 14, wherein the drive system (5) comprises a linear drive to which the gripping devices (10) are mounted, the linear drive being adapted to displace the gripping devices (10) from a loading position in which the gripping devices (10) are close to one another to a position in which the gripping devices (10) are spaced apart from one another and vice versa.

16. 15. A machine according to any one of claims 1 to 14, wherein the drive system (5) comprises two robot arms (7), each of which is provided with one gripping device (10), the robot arms (7) adapted to displace the gripping devices (10) from a loading position in which the gripping devices (10) are close to each other to a position in which the gripping devices (10) are spaced apart from each other and vice versa.

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