Gripper head and method of operating a gripper head

Abstract

The present invention relates to a gripper head (1) adapted to clamp, hold and release a cloth piece (2), the gripper head (1) comprising a first part (11) and a second part (33) with respective conveyor belts (6, 6'), an actuator (100), such as a hydraulic, pneumatic or motor, connected with the second part (33) and configured to rotate the second part (33) relative to the first part (11) to exert a first clamping force on the cloth piece (2) in a cloth clamping position, and a controller (C) connected with the actuator (100) and configured to control the actuator (100) for the second part (33) to selectively exert a second, higher clamping force in the cloth clamping position when the conveyor belts (6, 6') are temporarily stopped with a portion of the cloth piece (2) filling the clamping area Z.

Description

Technical Field

[0001] The present invention relates to a gripper including an improved gripper head adapted to clamp, hold and release cloth slabs, particularly for use in industrial laundry facilities where individual cloth slabs need to be picked up and pulled away from a pile of cloth slabs. Background Technology

[0002] WO2019 / 137585 discloses a gripper head comprising a pair of opposing conveyor belts in Figures 14 and 15. An elongated fabric clamping area is defined between the two conveyor belts, at a position where they face each other. A spring is used to rotate one of the two conveyor belts and bias it toward the fabric clamping position, thereby allowing the fabric to remain clamped in the fabric clamping area between the two conveyor belts.

[0003] A gripper with such a gripper head may preferably include a robotic arm having a gripper head mounted to its end. This gripper is adapted to move the gripper head between a receiving position and a conveying position, in which a conveyor belt contacts the fabric piece to be picked up, and in the conveying position, the picked-up fabric piece is conveyed to, for example, a conveyor or another gripper. (WO2019 / 137585) Figure 1 An example of a robotic arm with a gripper head is shown in the image.

[0004] For existing gripper heads, when in the receiving position, a fabric block is received by activating a conveyor belt to move in one direction. The portion of the fabric block in contact with the conveyor belt is then extracted from the fabric block pile through friction and enters the clamping area. Once the clamping area has been filled along its length, the conveyor belt stops and remains stationary, and the gripper head, along with the portion of the fabric block held between the conveyor belt by clamping force, moves away from the pile toward the conveyor position. In the conveyor position, the conveyor belt is activated to move in the opposite direction, thereby releasing the fabric block from the clamping area.

[0005] A spring that provides the aforementioned clamping force must be selected to reduce or eliminate the risk of the fabric piece falling off the gripper head as it is being removed from the stack and moved toward the conveyor position. A sensor mounted to the gripper head can preferably be used to determine when the clamping area is filled, such that the clamping force applied by the spring produces a relatively low clamping pressure applied to the fabric piece along the length of the clamping area.

[0006] Another example of a gripper head for clamping, holding and releasing cloth blocks is disclosed in WO94 / 27900.

[0007] In industrial laundries, there is a need to process batches of fabric made of delicate materials such as silk without leaving clamping marks, and to handle large and / or heavy wads of fabric using gripper heads of the type described above. Therefore, the present invention aims to provide an improved gripper head and a method of operating the gripper head, thereby at least partially eliminating the problems associated with processing wads of fabric of different materials and weights using one or the same gripper head. Summary of the Invention

[0008] According to a first aspect of the invention, the gripper head of the type mentioned above has further characteristic features of the first aspect of the invention.

[0009] According to a second aspect of the invention, a method of operating a gripper head of the type mentioned in the first aspect of the invention includes the steps of: activating an actuator of the gripper head to selectively apply a first clamping force to a piece of fabric in a clamping region and / or apply a second, higher clamping force to a piece of fabric in the clamping region.

[0010] Further preferred embodiments of the invention are defined in the appended aspects of the invention.

[0011] It should be noted that this invention can be used in conjunction with many types of fabrics, such as one or more of the following: textiles, clothing, towels, sheets, pillowcases, bed sheets, tablecloths, rags, kitchen towels, mops, dust mats, work clothes, robes, uniforms, shirts, socks, personal clothing, industrial work clothes, healthcare work clothes, food industry work clothes, baby fabrics, diapers, blankets, napkins, washing gloves, and other single-piece flexible articles. Whenever the term "fabric" is used hereinafter, it should be understood to mean one of the foregoing elements or elements of a similar nature. Attached Figure Description

[0012] Figure 1 The gripper head of the present invention is shown in its intended working environment.

[0013] Figure 2a These are front and rear views of an embodiment of the gripper head of the present invention, with and without a housing. The actuator arranged in the gripper head is not shown.

[0014] Figure 2b It shows the relationship with Figure 2a An exploded view of the gripper head of the present invention, similar to the gripper head shown, including a spring; the actuator arranged in the gripper head is not shown; and

[0015] Figure 3a and Figure 3b It shows the relationship with Figure 2aThe gripper head is similar to the gripper head of the present invention, which is rotated to two positions by an actuator, as seen in the front view and the front perspective view, respectively. Detailed Implementation

[0016] The invention will now be explained in more detail with reference to two embodiments.

[0017] Figure 1 A gripper with a robotic arm 26 bearing a gripper head 1 is shown, the gripper head 1 being in the process of transferring a piece of cloth 2 from a pile of similar cloth 4 to a conveyor or another gripper 5, wherein the gripper head 1 grasps a portion of the piece of cloth 2.

[0018] In handling large pieces of fabric 2, such as linen, it is desirable to raise the gripper head 1 by the robotic arm 26 to an elevated position such that approximately half or + / - 10% of the portion P of the fabric 2 between the portion held by the gripper head 1 and the suspended end E of the fabric 2 can be gripped by the gripper head of the gripper 5. This can be accomplished by first determining the size of the fabric 2 held by or to be held by the gripper head 1 and then moving the robotic arm 26 with the fabric 2 to an elevated position above the gripper 5 to which the fabric 2 will be transferred, wherein the elevated position for larger fabric 2 above the stack 4 is higher than the elevated position for smaller fabric 2. The size can be determined by a controller (not shown), for example, a camera, or visually or otherwise by an operator on a batch basis or relative to each fabric 2 placed in the stack 4. In this way, large pieces of fabric are conveyed forward in a folded form by the gripper 5, thereby reducing the length of the tail of the fabric 2, which is then held by the gripper 5 from the tail.

[0019] Figure 2a The invention illustrates a gripper head 1 having a first portion 11, which can be mounted to a robotic arm, such as... Figure 1 The end of the robotic arm 26 shown is used to move the gripper head 1 back and forth in three-dimensional space.

[0020] Figure 2a Corresponding to Figure 14 of WO19137585, but the gripper head 1 shown additionally includes an actuator disposed inside the first part 11 (in Figure 2a (Not found in the text), and its purpose will be discussed below.

[0021] Typically, the first part 11 carries two opposing conveyor belts 6, 6', which define a clamping area Z between them, i.e., at the position where they face each other (see...). Figure 3aThe fabric slab 2 in contact with the conveyor belts 6, 6' can be drawn into the clamping area Z by friction as the conveyor belts 6, 6'—which have been immersed in the pile 4 of fabric slab 2—move in a first direction. As shown, the first conveyor belt 6 of the two conveyor belts 6, 6' is a loop pulled around the first pair of rollers 8, 18, and the second conveyor belt 6' of the conveyor belts is a loop pulled around the second pair of rollers 8', 18'. A driver, preferably in the form of a motor 17, is configured to move the opposing surfaces of the two conveyor belts 6, 6' in a first upward direction, thereby stopping the movement of the conveyor belts 6, 6'—and holding them—when the clamping area Z is partially filled with fabric slab 2, and the driver is configured to then move the opposing surfaces of the two conveyor belts 6, 6' in opposite downward directions to release the fabric slab 2 from the clamping area Z.

[0022] Typically, the second part 33 of the gripper head 1 carries the second roller 18' of the second pair of rollers 8', 18' and is pivotally mounted to the first part 11. Therefore, the second part 33 can rotate relative to the first part 11 about the rotation axis 35 of the first (upper) roller 8' of the second pair of rollers 8', 18'. Figure 2b Neutralization is similar to that in Figure 3a The fabric clamping position shown is rotated from this position. In this position, the second roller 18' of the second pair of rollers 8', 18' and the second roller 18' of the first pair of rollers 8, 18' are close to each other, wherein the conveyor belts 6, 6' define a clamping area Z between them. When rotating away from the fabric clamping position, i.e., rotating to what can be called... Figure 2a and Figure 3b When the gripper head 1 is in the open configuration shown, it becomes more reliable to capture the cloth 2 in the pile 4 and extract it into the position that becomes the clamping area Z once the second part 33 has been rotated to its cloth clamping position, and may even be necessary if the cloth 2 is relatively hard.

[0023] exist Figure 2a In a slightly modified version of the gripper head 1 shown, the spring 34 is arranged to bias the second portion 33 toward the fabric clamping position, see [reference]. Figure 2b The advantage of this implementation is that the second part 33 can be deflected slightly away from the clamping position if necessary when the cloth piece 2 is picked up.

[0024] An actuator 100 connected to the first portion 11, such as—but not limited to—a hydraulic actuator, pneumatic actuator, or motor, is also connected to the second portion 33 at an extension of the second portion 33 located horizontally above the upper roller 8'. The actuator 100 is configured to rotate the second portion 33 relative to the first portion 11 about the axis of rotation 35 of the upper roller 8', and to hold the second portion 33 in a selected position, such as at… Figure 2b and Figure 3aIn the fabric clamping position shown, a portion of the fabric block can be held clamped in the clamping area Z between the two conveyor belts 6, 6'. Figure 2a and Figure 3b The second part 33 is shown as being rotated away from the clamping position by actuator 100. Controller C is used to control actuator 100.

[0025] In the first operating mode, the gripper head 1 is configured such that it is in the position of Figure 3a The second portion 33 in the aforementioned clamping position, as shown, applies a first, relatively low clamping force to the fabric block 2 held by the gripper head 1. This lower force can preferably be applied when the fabric block 2 is a) drawn into the clamping area Z by moving conveyor belts 6, 6', b) held in the clamping area Z, and c) moved to the conveying position by the robotic arm 26. This would be in the case where the fabric block 2 is considered to be made of a delicate material, thus requiring the use of a lower clamping pressure for processing. The first lower clamping force can be applied by the actuator 100, by the aforementioned spring 34, or by the actuator 100 and spring 34 acting together.

[0026] In another operating mode, actuator 100 can be operated such that second part 33 applies a selected second and higher clamping force when this alternative mode is selected, for example, i) only after the fabric 2 has been completely drawn into the clamping area Z and until the fabric 2 is released from the gripper head 1 in its transfer position, or ii) from the start of the process of drawing the fabric 2 into the clamping area Z until the fabric 2 is finally released from the gripper head 1 in its transfer position; in the latter case, controller C of gripper head 1 is configured to apply the second higher clamping force at an appropriate time. The second higher clamping force can preferably be applied by actuator 100. This operating mode can preferably be selected when heavy fabric lumps of non-fragile nature need to be drawn from the stack 4.

[0027] In an alternative implementation, the aforementioned spring 34 provides a higher clamping force, and the actuator 100 is configured to reduce this clamping force when the gripper head 1 is operating in the aforementioned first mode.

[0028] Controller C can connect to sensors to identify the type of cloth in stack 4, and—and thus—determine whether gripper head 1 should operate in a first mode or a second mode. Alternatively, the operator can manually select when gripper head 1 operates in one mode or another.

[0029] If necessary, controller C can be configured to control actuator 100 to rotate the second part 33 away from the clamping position, such as Figure 2a and Figure 3bAs shown, this may be desirable at the beginning of the stage when the fabric is drawn into the space between the two conveyor belts 6, 6'.

[0030] Note that the clamping force can be changed as needed by using a controller to properly set the actuator and / or by replacing any springs mentioned.

Claims

1. A gripper head (1) suitable for gripping, holding and releasing a piece of fabric (2), said gripper head (1) comprising: - A first part (11) carries two conveyor belts (6, 6'), the conveyor belts (6, 6') being configured to define a clamping area (Z) between the conveyor belts (6, 6'), the portion of the fabric piece (2) in contact with the conveyor belts (6, 6') being able to be drawn into the clamping area (Z) as the conveyor belts (6, 6') move in a first direction. - The first conveyor belt (6) of the conveyor belt is pulled around a rotatable first pair of rollers (8, 18), and the second conveyor belt (6') of the conveyor belt is pulled around a rotatable second pair of rollers (8', 18'). - At least one driver (17), said at least one driver (17) configured to: i) move the conveyor belt (6, 6') along the first direction; ii) temporarily stop moving the conveyor belt (6, 6') when the clamping area (Z) is filled by said portion of the cloth block (2); and iii) move the conveyor belt (6, 6') along the opposite second direction, and - Second part (33), the second part (33) carries the second roller (18') of the second pair of rollers (8', 18') and is pivotally mounted to the first part (11) for rotation relative to the first part (11) about the rotation axis of the first roller (8') of the second pair of rollers (8', 18') to and from the fabric clamping position, in which the clamping area (Z) is defined between the two conveyor belts (6, 6'). - The gripper head (1) is configured to apply a first clamping force to the fabric piece (2) in the clamping area (Z) at the fabric clamping position. Its features are, - An actuator (100), which is connected to the second part (33) and configured to rotate the second part (33) relative to the first part (11), and - A controller (C) connected to the actuator (100) and configured to control the actuator (100) for the second part (33) to apply a second higher clamping force to the cloth block (2) in the clamping area (Z) in the cloth clamping position.

2. The gripper head (1) according to claim 1, the spring (34) biases the second part (33) toward the cloth clamping position.

3. The gripper head (1) according to claim 2, wherein the spring (34) provides the first clamping force.

4. The gripper head (1) according to claim 2, wherein the controller (C) is configured to control the actuator (100) to apply the first clamping force together with the spring (34).

5. The gripper head (1) according to claim 1, wherein the controller (C) is configured to control the actuator (100) to apply the first clamping force to the cloth (2) when the cloth (2) is drawn into the clamping area (Z).

6. The gripper head (1) according to any one of claims 1 to 5, wherein the controller (C) is configured to control the actuator (100) to rotate the second portion (33) from the fabric clamping position to a position spaced apart by the conveyor belts (6, 6') for capturing the fabric piece (2) in the pile (4), and once the second portion (33) has been rotated to the fabric clamping position of the second portion (33), the fabric piece (2) is extracted into a position that becomes the clamping area (Z).

7. The gripper head (1) according to claim 1, wherein the first roller (8) of the first pair of rollers (8, 18) and the first roller (8') of the second pair of rollers (8', 18') are interconnected by toothed wheels (16, 16') for rotating the first roller (8) of the first pair of rollers (8, 18) and the first roller (8') of the second pair of rollers (8', 18') about their respective rotation axes, wherein at least one of the toothed wheels (16) is driven by a motor for clockwise and counterclockwise rotation.

8. The gripper head (1) according to claim 1, wherein the actuator (100) is a hydraulic actuator, a pneumatic actuator or a motor.

9. A gripper comprising a gripper head (1) according to any one of claims 1 to 8, the gripper head (1) being mounted to the end of a robotic arm (26) for reciprocating movement of the gripper head (1) in three-dimensional space.

10. A method of operating a gripper head (1) adapted to clamp, hold and release a piece of fabric (2), the gripper head (1) comprising: - A first part (11) carries two conveyor belts (6, 6'), the conveyor belts (6, 6') being configured to define a clamping area (Z) between the conveyor belts (6, 6'), the portion of the fabric piece (2) in contact with the conveyor belts (6, 6') being able to be drawn into the clamping area (Z) as the conveyor belts (6, 6') move in a first direction. - The first conveyor belt (6) of the conveyor belt is pulled around a rotatable first pair of rollers (8, 18), and the second conveyor belt (6') of the conveyor belt is pulled around a rotatable second pair of rollers (8', 18'). - At least one driver (17), said at least one driver (17) configured to: i) move the conveyor belt (6, 6') along the first direction; ii) temporarily stop moving the conveyor belt (6, 6') when the clamping area (Z) is filled by said portion of the cloth block (2); and iii) move the conveyor belt (6, 6') along the opposite second direction, and - Second part (33), the second part (33) carries the second roller (18') of the second pair of rollers (8', 18') and is pivotally mounted to the first part (11) for rotation relative to the first part (11) about the rotation axis of the first roller (8') of the second pair of rollers (8', 18') to and from the fabric clamping position, wherein the conveyor belts (6, 6') define the clamping area (Z) between the conveyor belts (6, 6'). - The second part (33) is configured to apply a first clamping force to the fabric block (2) in the fabric clamping position during the process of the fabric block (2) being drawn from the conveyor belt (6, 6') moving along the first direction into the clamping area (Z), and - An actuator (100) connected to the second part (33) and configured to rotate the second part (33) and hold the second part (33) in the fabric clamping position. The method includes the following steps: - Activate the actuator (100) to apply a first clamping force to the cloth block (2) in the clamping area (Z) and / or apply a second higher clamping force to the cloth block (2) in the clamping area (Z).

11. The method of claim 10, comprising the step of rotating the second portion (33) into the fabric clamping position by means of the actuator (100) before or after the fabric piece (2) is extracted into the clamping area (Z).

12. The method according to claim 10 or 11, wherein, The second part (33) rotates away from the cloth clamping position to a position spaced apart from the conveyor belts (6, 6') for capturing cloth pieces (2) in the pile (4), such that once the second part (33) has rotated to the cloth clamping position, the cloth piece (2) is extracted into the position that becomes the clamping area (Z).

13. The method according to claim 12, wherein, The gripper head (1) is mounted to the end of the robotic arm (26) for moving the gripper head (1) back and forth in three-dimensional space. The method includes the following steps: i) determining the size of the cloth block (2) held or to be held by the gripper head (1), and ii) then moving the robotic arm (26) with the cloth block (2) to an elevated position above the gripper (5) to which the cloth block (2) will be transferred, wherein the elevated position for a large cloth block (2) is higher than the elevated position for a smaller cloth block (2).

14. The method of claim 10, wherein, The actuator (100) is a hydraulic actuator, a pneumatic actuator, or a motor.

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