Clamping jaw for grabbing thin object and grabbing method

Abstract

The present invention provides a clamping jaw for grabbing a thin object and a grabbing method, relating to the technical field of robotic grabbers. The clamping jaw comprises a first clamping portion, a second clamping portion, and a driving mechanism, wherein the bottom of the first clamping portion is provided with a suctioning surface, the driving mechanism is drivingly connected to the second clamping portion, and the second clamping portion is provided on one side of the first clamping portion; in an initial state, the height of the suctioning surface is lower than that of the second clamping portion; and the driving mechanism can drive the second clamping portion to move to a position below the suctioning surface of the first clamping portion and clamp toward the suctioning surface of the first clamping portion, and the driving mechanism can drive the second clamping portion to move away from the suctioning surface of the first clamping portion and return to the initial state. The present invention uses a structure featuring single-side suctioning and double-side clamping, and the resulting clamping force significantly enhances grabbing and ensures operational safety. The clamping jaw is oriented substantially parallel to a target object, thereby avoiding any interference or obstruction between the clamping jaw and potential structures located below the target object. The present invention has broad applicability.

Description

Grippers and gripping methods for grasping thin objects Technical Field

[0001] This invention relates to the field of robotic gripper technology, specifically to a gripper and gripping method for grasping thin objects. Background Technology

[0002] Thin objects, i.e., sheet-like objects such as flexible printed circuits (FPCs) and flexible foil circuits (FFCs), are frequently handled on assembly lines. However, the nature of these thin objects, when oscillating in space, often leads to significant positional uncertainty. In other cases, thin objects may be placed on a platform with only one side exposed for easy pickup. This makes precise clamping with clamp-based fixtures difficult or impossible. Furthermore, in assembly scenarios, workspace is often limited, and traditional fixtures with opposing jaws can create obstacles.

[0003] To address this problem, attractive grippers are used to capture these objects. For example, vacuum suction cups can capture thin, suspended objects, thus explaining some of the uncertainty in the object's position.

[0004] Because thin objects have low rigidity, they require dexterity to assemble or insert. However, attraction-based grippers (such as vacuum grippers) cannot provide sufficient gripping force, causing gripping failure when dragging, rotating, or inserting the attracted object.

[0005] A Chinese patent with publication number CN211893857U discloses a vacuum adsorption clamping mechanism for packaging film based on a vial cutting and feeding machine. The mechanism includes a cylinder support, with pins C on one side of the top of both ends of the cylinder support. A cylinder is located at the middle position outside the pins C. The cylinder support is connected to the cylinder via pins C. A connector is provided at the output end of the cylinder. An upper clamping plate is provided on the bottom side of the cylinder support away from the cylinder. A suction cup is provided at the middle position on the side of the cylinder support away from the cylinder. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the purpose of this invention is to provide a gripper and gripping method for grasping thin objects, which combines attraction-based and clamping-based clamping mechanisms, and the novel clamping mechanism design minimizes the obstacles generated by the gripper.

[0007] According to the present invention, a gripper for gripping thin objects includes a first gripping part, a second gripping part, and a driving mechanism. The bottom of the first gripping part is provided with an adsorption surface. The driving mechanism is drivenly connected to the second gripping part. The second gripping part is disposed on one side of the first gripping part. The first gripping part achieves single-sided adsorption, and the first gripping part achieves double-sided clamping through the cooperation of the second gripping part.

[0008] During operation, the drive mechanism can drive the second gripping part to move below the adsorption surface of the first gripping part and clamp it to the adsorption surface of the first gripping part. In addition, the drive mechanism can drive the second gripping part away from the adsorption surface of the first gripping part.

[0009] Preferably, the driving mechanism is a biaxial linear actuator, including a first actuator and a second brake. One end of the first actuator is connected to the second gripping part, and the other end of the first actuator is connected to the second brake. The first actuator and the second brake respectively drive the second gripping part to move parallel to and perpendicular to the adsorption surface of the first gripping part.

[0010] Preferably, the drive mechanism achieves the transformation of the kinematic relationship of the linkage through elastic preload and limiting, thereby realizing the conversion of different motion modes.

[0011] Preferably, the drive mechanism includes a first rod, a second rod, a third rod, a fourth rod, and a fifth rod. The second clamping part is disposed at one end of the first rod. The first rod and the second rod are a rigidly connected integral structure. The first rod and the second rod are respectively connected to the third rod through a first joint. The other end of the third rod is mounted on a fixed end through a fifth joint. The other end of the second rod is connected to the fourth rod through a second joint. The fourth rod is connected to the fifth rod through a third joint. The fifth rod is mounted on a fixed end through a fourth joint. An elastic element is connected between the second joint and the fourth joint.

[0012] A hard stop is provided on one side of the first gripping part, and the hard stop is located on the movement path of the third rod.

[0013] Preferably, a rigid stop is provided between the fourth and fifth rods to limit their relative rotation, which cooperates to form a second equivalent rod, which is collinear with the elastic element.

[0014] Preferably, the drive mechanism is an integrated flexible mechanical drive mechanism composed of multiple connecting rods and multiple rotary joints. The connecting rods include a first connecting rod, a second connecting rod, a third connecting rod, and a fourth connecting rod. A second clamping part is disposed at one end of the first connecting rod. The other end of the first connecting rod is connected to the third connecting rod through a second rotary joint. The other end of the third connecting rod is connected to the fourth connecting rod through a fourth rotary joint. An angle is formed between the third connecting rod and the fourth connecting rod. The other end of the fourth connecting rod is mounted on a fixed end through a fifth rotary joint. The first connecting rod is connected to the second connecting rod through a first rotary joint. The other end of the second connecting rod is mounted on a fixed end through a third rotary joint.

[0015] A hard stop device is provided on one side of the first gripping part, and the hard stop device is located on the movement path of the second link.

[0016] Preferably, the stiffness of the rotary joint is lower than that of the connecting rod, and the stiffness of the fourth rotary joint is greater than that of the other rotary joints.

[0017] The present invention also provides a gripping method for a gripper used to grasp thin objects, comprising the following steps:

[0018] Step A1: Adsorb a thin object through the first gripping part;

[0019] Step A2: The second brake drives the second gripping part to move downwards until it is below the thin object;

[0020] Step A3: The first actuator drives the second gripping part to translate directly below the first gripping part;

[0021] In step A4, the second brake drives the second gripping part to move upward and clamp the thin object with the first gripping part.

[0022] The present invention also provides a gripping method for a gripper used to grasp thin objects, comprising the following steps:

[0023] Step B1: The first gripping part adsorbs a thin object;

[0024] Step B2: The drive mechanism drives the second gripping part to approach the first gripping part until the third rod stops directly below the first gripping part due to the restriction of the hard stop.

[0025] In step B3, the drive mechanism continues to approach the first gripping part, causing the first rod to rotate around the first joint, which in turn drives the second gripping part to move upward and clamp with the first gripping part.

[0026] The present invention also provides a gripping method for a gripper used to grasp thin objects, comprising the following steps:

[0027] Step C1: The first gripping part adsorbs a thin object;

[0028] Step C2: Drive the third rotary joint to rotate, which in turn drives the other rotary joints to rotate, causing the second gripping part to move from the side of the first gripping part toward the first gripping part until the second gripping part stops directly below the first gripping part due to the restriction of the hard stop device.

[0029] Step C3: Drive the fourth link to continue rotating along the rotation direction of the fifth rotary joint, causing the second clamping part to move upward and clamp with the first clamping part.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention employs a drive mechanism with different structures, enabling the gripper to tolerate high positional errors and to pick up objects by contacting only one surface of the attraction-based gripper, and to firmly grasp the gripper-based object.

[0032] 2. The present invention uses a first gripping part to achieve single-sided adsorption, overcoming the problem of 'limited space', and uses a second gripping part to achieve double-sided clamping, ensuring the stability and safety of subsequent operations; and when the gripper is not in use, the second gripping part retracts to the side of the first gripping part and is positioned above it, providing unobstructed space for the attracting tip to freely approach the target object;

[0033] 3. During the gripping process, the design of the gripping part ensures that the clamping mechanism mainly runs parallel to the target object from the side, preventing interference or obstruction between the gripping part and any potential structure, and is located below the target object during the gripping process.

[0034] 4. By adjusting the position of the first clamping part and the position of the hard stop, the movement of the mechanism can be adjusted to adapt to different thicknesses of thin objects, thus expanding the scope of application. Attached Figure Description

[0035] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0036] Figure 1(a)-(d) shows the changes in gripper gripping in Embodiment 1 and Embodiment 2 of the present invention;

[0037] Figure 2 is a schematic diagram of the gripper structure in Embodiment 3 of the present invention;

[0038] Figures 3-6 are diagrams showing the gripping variations of the gripper in Embodiment 4 of the present invention;

[0039] Figure 7 is a schematic diagram of the gripper structure in Embodiment 5 of the present invention;

[0040] Figures 8-12 are diagrams showing the changes in gripping action of the gripper in Embodiment 6 of the present invention.

[0041] The diagram shows: Detailed Implementation

[0042] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0043] Example 1

[0044] According to the present invention, a gripper for grasping thin objects, as shown in FIG1, includes a first gripping part 1, a second gripping part 2, and a driving mechanism. The bottom of the first gripping part 1 is provided with an adsorption surface. The driving mechanism is drivenly connected to the second gripping part 2. The second gripping part 2 is disposed on one side of the first gripping part 1. The first gripping part 1 achieves single-sided adsorption, and the first gripping part 1 achieves double-sided clamping through the cooperation of the second gripping part 2. The adsorption surface of the first gripping part 1 includes a vacuum suction cup, a magnetic tip, or an electrostatic tip. In the initial state, the height of the adsorption surface is lower than that of the second gripping part 2. The driving mechanism can drive the second gripping part 2 to move below the adsorption surface of the first gripping part 1 and clamp it against the adsorption surface of the first gripping part 1. Furthermore, the driving mechanism can drive the second gripping part 2 away from the adsorption surface of the first gripping part 1 and return to the initial state.

[0045] The driving mechanism is a biaxial linear actuator, including a first actuator 11 and a second brake 12. One end of the first actuator 11 is connected to the second gripping part 2, and the other end of the first actuator 11 is connected to the second brake 12. The first actuator 11 and the second brake 12 respectively drive the second gripping part 2 to move parallel to and perpendicular to the adsorption surface of the first gripping part 1.

[0046] More specifically, single-sided adsorption has minimal obstruction and interference, achieving high strength, and possesses a certain capture capability, meaning it can grasp objects even when the suction head cannot fully reach them. The disadvantage is that the grasping force is limited by atmospheric pressure, magnetic force, and electrostatic attraction, making it less reliable. Double-sided clamping has the advantage of a very firm grip, but requires contact from both sides, often leading to obstruction and interference. In this invention, the first gripping part performs single-sided suction to address interference issues caused by confined spaces and to overcome the problem of inaccurate positioning due to its air-to-air capture capability. After suction, the object is slightly moved to overcome the 'confined space' problem, and then the second gripping part clamps it securely, ensuring stability and safety for subsequent operations. This utilizes the advantages of both 'single-sided adsorption' and 'double-sided clamping'.

[0047] Example 2

[0048] The present invention also provides a gripping method for a gripper used to grasp thin objects in Embodiment 1, as shown in Figure 1, including the following steps:

[0049] Step A1: The thin object 6 is adsorbed by the first gripping part 1;

[0050] Step A2, the second brake 12 drives the second gripping part 2 to move downwards to below the thin object 6;

[0051] Step A3: The first actuator 11 drives the second gripping part 2 to translate directly below the first gripping part 1;

[0052] In step A4, the second brake 12 drives the second gripping part 2 to move upward and clamp the thin object 6 with the first gripping part 1.

[0053] Example 3

[0054] According to the present invention, a gripper for grasping thin objects, as shown in FIG2, includes a first gripping part 1, a second gripping part 2, and a driving mechanism. The bottom of the first gripping part 1 is provided with an adsorption surface. The driving mechanism is drivenly connected to the second gripping part 2, which is located on one side of the first gripping part 1. The adsorption surface of the first gripping part 1 includes a vacuum suction cup, a magnetic tip, or an electrostatic tip. In the initial state, the height of the adsorption surface is lower than that of the second gripping part 2. The driving mechanism can drive the second gripping part 2 to move below the adsorption surface of the first gripping part 1 and clamp it against the adsorption surface. Furthermore, the driving mechanism can drive the second gripping part 2 away from the adsorption surface of the first gripping part 1 and return it to the initial state.

[0055] The driving mechanism includes a first rod 21, a second rod 22, a third rod 23, a fourth rod 24, and a fifth rod 25. The second clamping part 2 is disposed at one end of the first rod 21. The first rod 21 and the second rod 22 are integral structures with rigid connection. The first rod 21 and the second rod 22 are respectively connected to the third rod 23 through the first joint 211. The other end of the third rod 23 is mounted on the fixed end through the fifth joint 215. The other end of the second rod 22 is connected to the fourth rod 24 through the second joint 212. The fourth rod 24 is connected to the fifth rod 25 through the third joint 213. The fifth rod 25 is mounted on the fixed end through the fourth joint 214. An elastic element 29 is connected between the second joint 212 and the fourth joint 214. Furthermore, the fourth rod 24 and the fifth rod 25 are directly provided with a rigid stop 28 for limiting their relative rotation, which cooperates to form a second equivalent rod 27. The second equivalent rod 27 and the elastic element 29 are collinear. A rigid stop 210 is provided on one side of the first gripping part 1, and the rigid stop 210 is located on the movement path of the third rod 23. A first equivalent rod 26 is provided between the fifth joint 215 and the fourth joint 214 for their cooperative stroke.

[0056] Example 4

[0057] The present invention also provides a gripping method for a gripper used to grasp thin objects in Embodiment 3, as shown in Figures 3-6. The specific operation steps are as follows:

[0058] Step B1, the first gripping part 1 adsorbs the thin object 6;

[0059] In step B2, the second lever 22, the third lever 23, the first equivalent lever 26, and the second equivalent lever 27 work together in a four-bar linkage mechanism to drive the second gripping part 2 to approach the first gripping part 1 until the second gripping part 2 is stopped directly below the first gripping part 1 by the hard stop 210.

[0060] In step B3, the drive mechanism continues to approach the first clamping part 1, causing the first rod 21 to rotate around the first joint 211. The second rod 22, the third rod 23, the fourth rod 24, the fifth rod 25, and the first equivalent rod 26 cooperate with the five-bar linkage mechanism to drive the second clamping part 2 to move upward and clamp the first clamping part 1.

[0061] In this embodiment, the resulting clamping force significantly enhances the grip, ensuring operational safety. More specifically, the release process is the reverse of the grasping process (capture and clamping) described above. Similarly, the lateral movement during the release process minimizes potential interference with the structure beneath the object.

[0062] Example 5

[0063] A gripper for grasping thin objects according to the present invention, as shown in FIG7, includes a first gripping part 1, a second gripping part 2, and a driving mechanism. The bottom of the first gripping part 1 is provided with an adsorption surface. The driving mechanism is drivenly connected to the second gripping part 2, which is disposed on one side of the first gripping part 1. The adsorption surface of the first gripping part 1 includes a vacuum suction cup, a magnetic tip, or an electrostatic tip. In the initial state, the height of the adsorption surface is lower than that of the second gripping part 2. The driving mechanism can drive the second gripping part 2 to move below the adsorption surface of the first gripping part 1 and clamp it against the adsorption surface. Furthermore, the driving mechanism can drive the second gripping part 2 away from the adsorption surface of the first gripping part 1 and return it to the initial state.

[0064] The drive mechanism is an integrated flexible mechanical drive mechanism composed of multiple connecting rods and multiple rotary joints. The stiffness of the rotary joints is lower than that of the connecting rods, and the stiffness of the fourth rotary joint 38 is greater than that of the other rotary joints. The connecting rods include a first connecting rod 32, a second connecting rod 35, a third connecting rod 36, and a fourth connecting rod 39. The second clamping part 2 is disposed at one end of the first connecting rod 32. The other end of the first connecting rod 32 is connected to the third connecting rod 36 through the second rotary joint 34. The other end of the third connecting rod 36 is connected to the fourth connecting rod 39 through the fourth rotary joint 38, and an angle is formed between the third connecting rod 36 and the fourth connecting rod 39. The other end of the fourth connecting rod 39 is mounted on a fixed end through a fifth rotary joint 310. The first connecting rod 32 is connected to the second connecting rod 35 through the first rotary joint 33. The other end of the second connecting rod 35 is mounted on a fixed end through a third rotary joint 37. A hard stop device 311 is disposed on one side of the first clamping part 1, and the hard stop device 311 is disposed on the moving path of the second connecting rod 35.

[0065] Example 6

[0066] The present invention also provides a gripping method for a gripper used to grasp thin objects in Embodiment 5, as shown in Figures 8-12, including the following steps:

[0067] Step C1: The first gripping part 1 adsorbs the thin object 6;

[0068] Step C2: Drive the third rotary joint 37 to rotate clockwise, which will cause the other rotary joints to rotate and drive the second clamping part 2 to move from the side of the first clamping part 1 toward the first clamping part 1 until the hard stop device 311 restricts the second clamping part 2 to stop directly below the first clamping part 1.

[0069] Step C3: Drive the fourth link 39 to continue rotating clockwise along the rotation direction of the fifth rotary joint 310, causing the second clamping part 2 to move upward and clamp with the first clamping part 1.

[0070] In this embodiment, the resulting clamping force significantly enhances the grip, ensuring operational safety. More specifically, the release process is the reverse of the grasping process (capture and clamping) described above. Similarly, the lateral movement during the release process minimizes potential interference with the structure beneath the object.

[0071] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0072] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A gripper for grasping thin objects, characterized in that, It includes a first clamping part (1), a second clamping part (2) and a driving mechanism. The bottom of the first clamping part (1) is provided with an adsorption surface. The driving mechanism is driven to connect with the second clamping part (2). The second clamping part (2) is located on one side of the first clamping part (1). The first clamping part (1) realizes single-sided adsorption. The first clamping part (1) achieves double-sided clamping through the cooperation of the second clamping part (2). During operation, the driving mechanism drives the second clamping part (2) to move below the adsorption surface of the first clamping part (1) and clamps it to the adsorption surface of the first clamping part (1). Furthermore, the driving mechanism can drive the second clamping part (2) away from the adsorption surface of the first clamping part (1).

2. The gripper for grasping thin objects as described in claim 1, characterized in that, The driving mechanism is a biaxial linear actuator, including a first actuator (11) and a second actuator (12). One end of the first actuator (11) is connected to the second gripping part (2), and the other end of the first actuator (11) is connected to the second brake (12). The first actuator (11) and the second brake (12) respectively drive the second gripping part (2) to move parallel to and perpendicular to the adsorption surface of the first gripping part (1).

3. The gripper for grasping thin objects as described in claim 1, characterized in that, The drive mechanism achieves the transformation of the kinematic relationship of the linkage through elastic preload and limiting, thereby realizing the conversion of different motion modes.

4. The gripper for grasping thin objects as described in claim 3, characterized in that, The driving mechanism includes a first rod (21), a second rod (22), a third rod (23), a fourth rod (24), and a fifth rod (25). The second clamping part (2) is disposed at one end of the first rod (21). The first rod (21) and the second rod (22) are rigidly connected integral structures. The first rod (21) and the second rod (22) are respectively connected to the third rod (23) through a first joint (211). The other end of the third rod (23) is mounted on a fixed end through a fifth joint (215). The other end of the second rod (22) is connected to the fourth rod (24) through a second joint (212). The fourth rod (24) is connected to the fifth rod (25) through a third joint (213). The fifth rod (25) is mounted on a fixed end through a fourth joint (214). An elastic element (29) is connected between the second joint (212) and the fourth joint (214). A hard stop (210) is provided on one side of the first clamping part (1), and the hard stop (210) is provided on the moving path of the third rod (23).

5. The gripper for grasping thin objects as described in claim 4, characterized in that, A rigid stop (28) for limiting the relative rotation of the fourth rod (24) and the fifth rod (25) is provided between them, and a second equivalent rod (27) is formed in cooperation with it. The second equivalent rod (27) is collinear with the elastic element (29).

6. The gripper for grasping thin objects as described in claim 3, characterized in that, The drive mechanism is an integrated flexible mechanical drive mechanism composed of multiple connecting rods and multiple rotary joints. The connecting rods include a first connecting rod (32), a second connecting rod (35), a third connecting rod (36), and a fourth connecting rod (39). The second clamping part (2) is disposed at one end of the first connecting rod (32). The other end of the first connecting rod (32) is connected to the third connecting rod (36) through a second rotary joint (34). The other end of the third connecting rod (36) is connected to the fourth connecting rod (39) through a fourth rotary joint (38). An angle is formed between the third connecting rod (36) and the fourth connecting rod (39). The other end of the fourth connecting rod (39) is mounted on a fixed end through a fifth rotary joint (310). The first connecting rod (32) is connected to the second connecting rod (35) through a first rotary joint (33). The other end of the second connecting rod (35) is mounted on a fixed end through a third rotary joint (37). A hard stop device (311) is provided on one side of the first clamping part (1), and the hard stop device (311) is provided on the moving path of the second connecting rod (35).

7. The gripper for grasping thin objects as described in claim 6, characterized in that, The stiffness of the rotary joint is lower than that of the connecting rod, and the stiffness of the fourth rotary joint (38) is greater than that of the other rotary joints.

8. A gripping method for a gripper for grasping thin objects as described in claim 2, characterized in that, Includes the following steps: Step A1: The thin object (6) is adsorbed by the first gripping part (1); In step A2, the second brake (12) drives the second gripping part (2) to move downwards below the thin object (6); Step A3, the first actuator (11) drives the second gripping part (2) to translate directly below the first gripping part (1); In step A4, the second brake (12) drives the second clamping part (2) to move upward and clamp the thin object (6) with the first clamping part (1).

9. A gripping method for a gripper for grasping a thin object as described in claim 4 or 5, characterized in that, Includes the following steps: Step B1, the first gripping part (1) adsorbs the thin object (6); Step B2, the drive mechanism drives the second gripping part (2) to approach the first gripping part (1) until the third rod (23) stops directly below the first gripping part (1) due to the restriction by the hard stop (210); In step B3, the driving mechanism continues to approach the first clamping part (1), causing the first rod (21) to rotate around the first joint (211), thereby driving the second clamping part (2) to move upward and clamp with the first clamping part (1).

10. A gripping method for a gripper for grasping a thin object as described in claim 6 or 7, characterized in that, Includes the following steps: Step C1, the first gripping part (1) adsorbs the thin object (6); Step C2, drive the third rotary joint (37) to rotate, drive the other rotary joints to rotate, and drive the second clamping part (2) to move from the side of the first clamping part (1) toward the first clamping part (1) until the second clamping part (2) stops directly below the first clamping part (1) due to the restriction of the hard stop device (311); Step C3: Drive the fourth link (39) to continue rotating along the rotation direction of the fifth rotary joint (310), causing the second clamping part (2) to move upward and clamp with the first clamping part (1).

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