Clamping jaw for grabbing thin object and grabbing method

Abstract

The invention provides a clamping jaw for grabbing a thin object and a grabbing method, and relates to the technical field of robot grabber, the clamping jaw comprises a first clamping part, a second clamping part and a driving mechanism, the bottom of the first clamping part is provided with an adsorption surface, the driving mechanism is in driving connection with the second clamping part, and the second clamping part is arranged on one side of the first clamping part; in an initial state, the adsorption surface is lower than the second clamping part; the driving mechanism can drive the second clamping part to move to the position below the adsorption face of the first clamping part and clamp the adsorption face of the first clamping part, and the driving mechanism can drive the second clamping part to be away from the adsorption face of the first clamping part and return to the initial state. A single-face adsorption and double-face clamping structure is adopted, the generated clamping force remarkably strengthens grabbing, the operation safety is ensured, the clamping jaw is mainly parallel to the orientation of the target object, therefore, any interference or obstruction between the clamping jaw and a potential structure below the target object is avoided, and the application range is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of robot grippers, and in particular to a gripper for gripping thin objects and a gripping method. Background Art

[0002] Thin objects, i.e. sheet-like objects such as flexible printed circuits (FPCs) and flexible foil circuits (FFCs), are frequently handled components on assembly lines. However, the nature of these thin objects often results in a high degree of positional uncertainty as they oscillate in space. In other cases, thin objects can be placed on a platform with only one side exposed for easy picking. Such practices can make precise gripping with clamping-based grippers difficult or impossible. Furthermore, in assembly scenarios, workspace is often limited and traditional grippers with opposing jaws create obstacles.

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

[0004] Due to the low rigidity of thin objects, dexterous manipulation is required to assemble or insert them. However, suction-based grippers, such as vacuum suction grippers, cannot provide sufficient grasping force, resulting in grasping failures when dragging, rotating, or inserting the attracted objects.

[0005] The existing Chinese patent with publication number CN211893857U discloses a packaging film vacuum adsorption clamping mechanism based on a vial film cutting and bottle feeding machine, including a cylinder bracket, a pin C is provided on one side of the top of both ends of the cylinder bracket, a cylinder is provided at the middle position outside the pin C, the cylinder bracket is connected to the cylinder through the pin C, a connecting head is provided at the output end of the cylinder, an upper clamping plate is provided on the side of the bottom of the cylinder bracket away from the cylinder, and a suction cup bracket is provided at the middle position of the side of the cylinder bracket away from the cylinder. Summary of the invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a clamping claw and a method for grasping thin objects, which combines a suction-based and a clamping-based clamping mechanism, and the novel clamping mechanism design minimizes the obstacles caused by the clamping claw.

[0007] According to the present invention, a clamping claw for grasping a thin object comprises a first clamping part, a second clamping part and a driving mechanism, wherein a suction surface is arranged at the bottom of the first clamping part, the driving mechanism is drivingly connected to the second clamping part, the second clamping part is arranged at one side of the first clamping part, the first clamping part realizes single-sided suction, and the first clamping part realizes double-sided clamping through the cooperation of the second clamping part;

[0008] During operation, the driving mechanism can drive the second clamping part to move below the adsorption surface of the first clamping part and clamp the adsorption surface of the first clamping part, and the driving mechanism can drive the second clamping part away from the adsorption surface of the first clamping 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 clamping part, and the other end of the first actuator is connected to the second brake, and the first actuator and the second brake respectively drive the second clamping part to move parallel and perpendicular to the adsorption surface of the first clamping part.

[0010] Preferably, the driving mechanism realizes the transformation of the kinematic relationship of the connecting rod by means of elastic pre-tightening and limiting, thereby realizing the conversion of different motion modes.

[0011] Preferably, the driving mechanism comprises a first rod, a second rod, a third rod, a fourth rod and a fifth rod, the second clamping portion is arranged at one end of the first rod, the first rod and the second rod are a rigidly connected integrated 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 the 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 the fixed end through a fourth joint, and an elastic element is connected between the second joint and the fourth joint;

[0012] A hard stopper is provided on one side of the first clamping portion, and the hard stopper is provided on a moving path of the third rod.

[0013] Preferably, a hard stopper is provided between the fourth rod and the fifth rod for limiting relative rotation therebetween, and a second equivalent rod is formed by cooperation therebetween, and the second equivalent rod is colinear with the elastic element.

[0014] Preferably, the driving mechanism is an integrated flexible mechanical driving mechanism composed of a plurality of connecting rods and a plurality of rotating joints, the connecting rods include a first connecting rod, a second connecting rod, a third connecting rod and a fourth connecting rod, the second clamping portion is arranged at one end of the first connecting rod, the other end of the first connecting rod is connected to the third connecting rod through the second rotating joint, the other end of the third connecting rod is connected to the fourth connecting rod through the fourth rotating joint, and 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 the fixed end through the fifth rotating joint, the first connecting rod is connected to the second connecting rod through the first rotating joint, and the other end of the second connecting rod is mounted on the fixed end through the third rotating joint;

[0015] A hard stop device is provided at one side of the first clamping portion, and the hard stop device is provided on the moving path of the second connecting rod.

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

[0017] The present invention also provides a gripping method for a clamping claw for gripping a thin object, comprising the following steps:

[0018] Step A1, sucking the thin object by the first clamping part;

[0019] Step A2, the second brake drives the second clamping part to move downward to below the thin object;

[0020] Step A3, the first actuator drives the second clamping portion to translate to just below the first clamping portion;

[0021] Step A4: the second brake drives the second clamping part to move upward to clamp the thin object with the first clamping part.

[0022] The present invention also provides a gripping method for a clamping claw for gripping a thin object, comprising the following steps:

[0023] Step B1, the first clamping part absorbs the thin object;

[0024] Step B2, the driving mechanism drives the second clamping portion to approach the first clamping portion until the third rod is restricted by the hard stopper so as to stop just below the first clamping portion;

[0025] Step B3, the driving mechanism continues to approach the first clamping part, so that the first rod rotates around the first joint, driving the second clamping part to move upward and clamp with the first clamping part.

[0026] The present invention also provides a gripping method for a clamping claw for gripping a thin object, comprising the following steps:

[0027] Step C1, the first clamping part absorbs the thin object;

[0028] Step C2, driving the third rotary joint to rotate, driving the other rotary joints to rotate, driving the second clamping part to approach the first clamping part from the side of the first clamping part, until the second clamping part is restricted by the hard stop device so that it stops directly below the first clamping part;

[0029] Step C3, driving the fourth connecting rod to continue rotating along the rotation direction of the fifth rotating joint, driving 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 adopts a driving mechanism of different structures to enable the gripper to have the ability to tolerate high position errors, the ability to pick up objects by only contacting one surface of the gripper based on attraction, and the ability to firmly grasp the gripper based on clamping;

[0032] 2. The present invention adopts the first clamping part to achieve single-sided adsorption, breaking the problem of "small space", and adopts the second clamping part to achieve double-sided clamping, ensuring the stability and safety of subsequent operations; and when the clamping claw is not in use, the second clamping part retracts to the side of the first clamping part and is positioned above it, providing an unobstructed space for the suction tip to freely approach the target object;

[0033] 3. The design of the movement of the gripping part during the gripping process of the present invention ensures that the clamping mechanism mainly operates from the side parallel to the target object, 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. The present invention can adjust the movement of the mechanism to adapt to different thicknesses of thin objects by adjusting the position of the first clamping portion and the position of the hard stopper, thereby expanding the scope of application. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0036] Figure 1 (a)-(d) are diagrams showing the changes in gripping of the gripper in Examples 1 and 2 of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of the clamp in Example 3 of the present invention;

[0038] Figure 3-Figure 6 This is a diagram showing the gripping changes of the clamping jaws in Example 4 of the present invention;

[0039] Figure 7 This is a schematic diagram of the structure of the clamp in Example 5 of the present invention;

[0040] Figure 8-Figure 12 This is a diagram showing the gripping changes of the clamp in Example 6 of the present invention.

[0041] The figure shows:

[0042] DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0044] Example 1

[0045] According to the present invention, a clamping claw for grasping a thin object is provided, such as Figure 1 As shown, 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 connected to the second clamping part 2 by driving. The second clamping part 2 is arranged on one side of the first clamping part 1. The first clamping part 1 realizes single-sided adsorption, and the first clamping part 1 realizes double-sided clamping through the cooperation of the second clamping part 2. And the adsorption surface of the first clamping 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 clamping part 2; the driving mechanism can drive the second clamping part 2 to move below the adsorption surface of the first clamping part 1 and clamp to the adsorption surface of the first clamping part 1, and the driving mechanism can drive the second clamping part 2 away from the adsorption surface of the first clamping part 1 and return to the initial state.

[0046] 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 clamping 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 clamping part 2 to move parallel and perpendicular to the adsorption surface of the first clamping part 1.

[0047] More specifically, single-sided adsorption has little occlusion and interference, can reach a strong line, and has a certain capture ability, that is, it has a certain ability to grab objects in the air. When the suction head cannot completely touch the object, it is still possible to capture the object; the disadvantage is that the grabbing force is limited by atmospheric pressure / magnetic force / electrostatic adsorption force, which is not reliable enough. The advantage of double-sided clamping is that it can be pinched very firmly, but the disadvantage is that it requires double-sided contact, which often brings occlusion and interference. When the present invention is working, it first uses the first clamping part to perform unilateral suction to deal with the interference problem caused by the narrow space, and uses its capture in the air to deal with the problem of inaccurate positioning. After suction, move the object slightly to solve the problem of "small space", and then clamp it with the second clamping part to ensure the stability and safety of subsequent operations, thus utilizing the respective advantages of "single-sided adsorption" and "double-sided clamping".

[0048] Example 2

[0049] The present invention also provides a method for grasping a thin object by using the clamp in Embodiment 1, such as Figure 1 As shown, the following steps are included:

[0050] Step A1, sucking the thin object 6 by the first clamping part 1;

[0051] Step A2, the second brake 12 drives the second clamping part 2 to move downward to below the thin object 6;

[0052] Step A3, the first actuator 11 drives the second clamping part 2 to translate to just below the first clamping part 1;

[0053] Step A4: the second brake 12 drives the second clamping part 2 to move upward to clamp the thin object 6 with the first clamping part 1 .

[0054] Example 3

[0055] According to the present invention, a clamping claw for grasping a thin object is provided, such as Figure 2 As shown, 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 connected to the second clamping part 2 by driving. The second clamping part 2 is arranged on one side of the first clamping part 1. The adsorption surface of the first clamping 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 clamping part 2; the driving mechanism can drive the second clamping part 2 to move below the adsorption surface of the first clamping part 1 and clamp to the adsorption surface of the first clamping part 1, and the driving mechanism can drive the second clamping part 2 away from the adsorption surface of the first clamping part 1 and return to the initial state.

[0056] 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 portion 2 is arranged at one end of the first rod 21. The first rod 21 and the second rod 22 are a rigidly connected integrated structure. The first rod 21 and the second rod 22 are respectively connected to the third rod 23 through a first joint 211, and the other end of the third rod 23 is installed on the 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, and the fifth rod 25 is installed on the fixed end through a fourth joint 214. An elastic element 29 is connected between the second joint 212 and the fourth joint 214; and the fourth rod 24 and the fifth rod 25 are directly provided with a hard stopper 28 for limiting the relative rotation of the two, and cooperate to form a second equivalent rod 27, and the second equivalent rod 27 is collinear with the elastic element 29. A hard stopper 210 is provided on one side of the first clamping part 1, and the hard stopper 210 is provided on the moving path of the third rod 23. A first equivalent rod 26 is provided between the fifth joint 215 and the fourth joint 214 in a coordinated stroke.

[0057] Example 4

[0058] The present invention also provides a method for grasping a thin object by a gripper in Embodiment 3, such as Figure 3-Figure 6 The specific steps are as follows:

[0059] Step B1, the first clamping part 1 absorbs the thin object 6;

[0060] Step B2, the second rod 22, the third rod 23, the first equivalent rod 26 and the second equivalent rod 27 cooperate with the travel four-bar linkage mechanism, and the driving mechanism drives the second clamping part 2 to approach the first clamping part 1 until the second clamping part 2 is limited by the hard stopper 210 so that it stops just below the first clamping part 1;

[0061] In step B3, the driving mechanism continues to approach the first clamping part 1, so that the first rod 21 rotates around the first joint 211, and 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-rod linkage mechanism to drive the second clamping part 2 to move upward and clamp the first clamping part 1.

[0062] In this embodiment, the resulting clamping force significantly enhances the grip and ensures safe operation. More specifically, the release process is the opposite of the above-mentioned capture process (capture and clamping). Similarly, the lateral movement during the release process minimizes potential interference with the structure below the object.

[0063] Example 5

[0064] According to the present invention, a clamping claw for grasping a thin object is provided, such as Figure 7 As shown, 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 connected to the second clamping part 2 by driving. The second clamping part 2 is arranged on one side of the first clamping part 1. The adsorption surface of the first clamping 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 clamping part 2; the driving mechanism can drive the second clamping part 2 to move below the adsorption surface of the first clamping part 1 and clamp to the adsorption surface of the first clamping part 1, and the driving mechanism can drive the second clamping part 2 away from the adsorption surface of the first clamping part 1 and return to the initial state.

[0065] The driving mechanism is an integrated flexible mechanical driving mechanism composed of a plurality of connecting rods and a plurality of rotating joints, and the rigidity of the rotating joint is lower than that of the connecting rod, and the rigidity of the fourth rotating joint 38 is greater than that of other rotating 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 portion 2 is arranged 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 rotating joint 34, the other end of the third connecting rod 36 is connected to the fourth connecting rod 39 through a fourth rotating 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 the fixed end through a fifth rotating joint 310, the first connecting rod 32 is connected to the second connecting rod 35 through a first rotating joint 33, and the other end of the second connecting rod 35 is mounted on the fixed end through a third rotating joint 37; a hard stop device 311 is arranged on one side of the first clamping portion 1, and the hard stop device 311 is arranged on the moving path of the second connecting rod 35.

[0066] Example 6

[0067] The present invention also provides a method for grasping a thin object by a gripper in Embodiment 5, such as Figure 8-Figure 12 The following steps are involved:

[0068] Step C1, the first clamping part 1 absorbs the thin object 6;

[0069] Step C2, driving the third rotary joint 37 to rotate clockwise, driving the other rotary joints to rotate, driving the second clamping part 2 to approach the first clamping part 1 from the side of the first clamping part 1, until the second clamping part 2 is restricted by the hard stop device 311 so that it stops directly below the first clamping part 1;

[0070] Step C3, driving the fourth connecting rod 39 to continue to rotate clockwise along the rotation direction of the fifth rotating joint 310, driving the second clamping part 2 to move upward and clamp with the first clamping part 1.

[0071] In this embodiment, the resulting clamping force significantly enhances the grip and ensures safe operation. More specifically, the release process is the opposite of the above-mentioned capture process (capture and clamping). Similarly, the lateral movement during the release process minimizes potential interference with the structure below the object.

[0072] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0073] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A gripper for grasping thin objects, characterized in that: The invention comprises a first clamping part (1), a second clamping part (2) and a driving mechanism, wherein the bottom of the first clamping part (1) is provided with an adsorption surface, the driving mechanism is connected to the second clamping part (2) by driving, the second clamping part (2) is arranged on one side of the first clamping part (1), the first clamping part (1) realizes single-sided adsorption, and the first clamping part (1) realizes double-sided clamping through the cooperation of the second clamping part (2); When in operation, the driving mechanism drives the second clamping part (2) to move below the adsorption surface of the first clamping part (1) and clamps the adsorption surface of the first clamping part (1), and 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 according to claim 1, characterized in that: The driving mechanism is a biaxial linear actuator, comprising a first actuator (11) and a second actuator (12); one end of the first actuator (11) is connected to the second clamping portion (2); the other end of the first actuator (11) is connected to a second brake (12); the first actuator (11) and the second brake (12) respectively drive the second clamping portion (2) to move parallel to and perpendicular to the adsorption surface of the first clamping portion (1).

3. The gripper for grasping thin objects according to claim 1, characterized in that: The driving mechanism realizes the transformation of the kinematic relationship of the connecting rod by means of elastic preload and limit, thereby realizing the conversion of different motion modes.

4. The gripper for grasping thin objects according to claim 3, characterized in that: The driving mechanism comprises a first rod (21), a second rod (22), a third rod (23), a fourth rod (24) and a fifth rod (25); the second clamping portion (2) is arranged at one end of the first rod (21); the first rod (21) and the second rod (22) are a rigidly connected integrated structure; 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 the 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 stopper (210) is provided on one side of the first clamping portion (1), and the hard stopper (210) is provided on the moving path of the third rod (23).

5. The gripper for grasping thin objects according to claim 4, characterized in that: A hard stopper (28) is provided between the fourth rod (24) and the fifth rod (25) for limiting relative rotation therebetween, and a second equivalent rod (27) is formed in cooperation therewith, wherein the second equivalent rod (27) is colinear with the elastic element (29).

6. The gripper for grasping thin objects according to claim 3, characterized in that: The driving mechanism is an integrated flexible mechanical driving mechanism composed of a plurality of connecting rods and a plurality of rotating 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 portion (2) is arranged 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 rotating joint (34). The other end of the third connecting rod (36) is connected to the fourth connecting rod (39) through a fourth rotating 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 rotating joint (310). The first connecting rod (32) is connected to the second connecting rod (35) through a first rotating joint (33). The other end of the second connecting rod (35) is mounted on a fixed end through a third rotating joint (37). A hard stop device (311) is provided on one side of the first clamping portion (1), and the hard stop device (311) is arranged on the moving path of the second connecting rod (35).

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

8. A method for gripping a thin object with a gripper according to claim 2, characterized in that: The following steps are involved: Step A1, sucking the thin object (6) by the first clamping part (1); Step A2, the second brake (12) drives the second clamping portion (2) to move downward to below the thin object (6); Step A3, the first actuator (11) drives the second clamping portion (2) to translate to just below the first clamping portion (1); Step A4: the second brake (12) drives the second clamping part (2) to move upwards, and clamps the thin object (6) together with the first clamping part (1).

9. A method for gripping a thin object with a gripper according to any one of claims 4 or 5, characterized in that: The following steps are involved: Step B1, the first clamping portion (1) absorbs the thin object (6); Step B2, the driving mechanism drives the second clamping portion (2) to approach the first clamping portion (1) until the third rod (23) is stopped directly below the first clamping portion (1) by the restriction of the hard stopper (210); Step B3, the driving mechanism continues to approach the first clamping part (1), so that the first rod (21) rotates around the first joint (211), driving the second clamping part (2) to move upward and clamp with the first clamping part (1).

10. A method for gripping a thin object with a gripper according to any one of claims 6 or 7, characterized in that: The following steps are involved: Step C1, the first clamping portion (1) absorbs the thin object (6); Step C2, driving the third rotating joint (37) to rotate, driving the other rotating joints to rotate, driving the second clamping part (2) to approach the first clamping part (1) from the side of the first clamping part (1), until the second clamping part (2) is restricted by the hard stop device (311) so that it stops directly below the first clamping part (1); Step C3, driving the fourth connecting rod (39) to continue rotating along the rotation direction of the fifth rotating joint (310), driving the second clamping part (2) to move upward and clamp with the first clamping part (1).

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