Electromagnetic flexible clamp

Abstract

The utility model relates to the technical field of the fixture for grabbing workpiece, and electromagnetic flexible fixture includes the base for connecting with manipulator, and the base is connected with the grab lever through four connecting rod mechanisms, and the end of grab lever is equipped with electromagnet, and reset spring is equipped between four connecting rod mechanisms and base. Directly absorb workpiece by electromagnet, it is more convenient, and the posture of workpiece is not limited, compact, small and light in weight, can adapt to the collaborative robot of light load, the clever structure design can reduce processing expense and cost, four connecting rod mechanisms cooperate with spring, and can effectively and reliably buffer in the process of grabbing workpiece, still have the characteristics of low resistance and low shaking in the use process.

Description

Technical Field

[0001] This utility model relates to the field of clamping fixtures for gripping workpieces, and specifically to an electromagnetic flexible clamp. Background Technology

[0002] Vibratory feeder loading is the first key process in automated assembly, transforming disordered parts into an ordered supply, such as the common loading of bolts. Utility model patent CN113695905B discloses an assembly machine for automotive seatbelt locking bolts. It first uses a vibratory feeder to sort the disordered bolts, then uses a gripper mechanism to grasp them and place them at the appropriate workstation for assembly. This method is relatively conventional. With the development of robot vision technology, vision camera-based gripping systems are becoming the trend. Vision camera-based gripping systems no longer require a vibratory feeder; instead, a gripper, guided by a vision camera, directly grasps workpieces from a pile. Grippers often use electric parallel grippers, which sometimes lack suitable gripping gaps in a pile of workpieces, making successful grasping difficult. Furthermore, existing electric parallel grippers are heavy and prone to collisions with workpieces during the gripping process. Utility Model Content

[0003] The purpose of this invention is to provide an electromagnetic flexible gripper suitable for vision camera-based grasping systems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An electromagnetic flexible gripper includes a base for connection with a robotic arm, the base being connected to a gripper via a four-bar linkage, the gripper having an electromagnet at its end; and a return spring between the four-bar linkage and the base.

[0006] Furthermore, the four-bar linkage includes a first link, a second link, a third link, and a fourth link. One end of the first link is connected to the base, the second link is connected to the grab bar, the third link has a hinge point with the first link and the second link, and the fourth link has a hinge point with the first link and the second link.

[0007] Furthermore, the fourth link has a hook-on portion for connecting one end of the return spring.

[0008] Furthermore, the fourth link includes a pair of fourth connecting plates arranged in parallel, with a first hanging shaft connecting the two fourth connecting plates. The first hanging shaft forms the hanging part, and a second hanging shaft is provided on the base for connecting the other end of the return spring.

[0009] Furthermore, the first link is formed by a first connecting plate, the second link is formed by a second connecting plate, the third link includes two parallel third connecting plates located on both sides of the first link, and the fourth link includes two parallel fourth connecting plates located on both sides of the first link.

[0010] Furthermore, each of the aforementioned hinge points is provided with a bearing.

[0011] Furthermore, the gripping rod is provided with a number of sequentially spaced connecting holes, and the second connecting rod is connected to the gripping rod by bolts and can selectively use the connecting holes therein.

[0012] Furthermore, a positioning groove is provided on one side of the grab rod for the second connecting rod to slide and engage.

[0013] Furthermore, the electromagnet has an arc-shaped groove adapted to the shape of the workpiece to be gripped.

[0014] Furthermore, the grab bar is an L-shaped bar, and the electromagnet is bolted to the bent section of the L-shaped bar.

[0015] The beneficial effects of this utility model are:

[0016] (1) Compared with the existing electric parallel grippers, the problem of grippers not having a suitable gripping gap in the workpiece pile is avoided, and the workpiece can be directly adsorbed by electromagnet.

[0017] (2) The connecting rod, base, gripper and other components are all made of aluminum alloy, which is compact, small and lightweight, and can be adapted to collaborative robots with light loads.

[0018] (3) The structure is ingeniously designed. The upper and lower limits are directly utilized by the corresponding parts of the connecting rod and the base. No additional limiting parts are needed, which reduces the number of parts, facilitates processing and manufacturing, and reduces processing costs and expenses.

[0019] (4) The four-bar linkage, in conjunction with the spring, can effectively and reliably buffer the workpiece during the gripping process, preventing collisions between the electromagnet and the workpiece.

[0020] (5) The hinge joint of the linkage mechanism is equipped with a bearing to ensure low resistance and low sway, and improve service life. Attached Figure Description

[0021] Figure 1 This is a structural schematic diagram of the electromagnetic flexible clamp of this utility model (in a stretched state);

[0022] Figure 2 This is a schematic diagram of the structure of the electromagnetic flexible clamp of this utility model (in a compressed state);

[0023] Figure 3 This is a schematic diagram illustrating the application scenario of the electromagnetic flexible clamp of this utility model.

[0024] 1. Base; 2. Four-bar linkage; 21. First link; 22. Second link; 23. Third link; 24. Fourth link; 3. Grab bar; 31. Connecting hole; 4. Electromagnet; 41. Arc groove; 5. Hinge pin; 6. Return spring; 71. First hanger; 72. Second hanger; 81. First limit point; 82. Second limit point; 91. Robot; 92. 3D camera. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art are within the protection scope of the present utility model.

[0026] Embodiments of this utility model:

[0027] like Figures 1-3 As shown, the electromagnetic flexible gripper includes a base 1 for connection with a robotic arm. The base 1 is connected to a gripping rod 3 via a four-bar linkage 2, which acts as a buffer. An electromagnet 4 is located at the end of the gripping rod 3. When energized, it generates an attractive force to grip the workpiece, replacing the existing parallel gripper method. A return spring 6 is provided between the four-bar linkage 2 and the base 1 to maintain the flexibility and resettlement of the overall movement. This is the basic structure. In this embodiment, the workpiece gripped is a bolt. The specific structure and working principle are described below.

[0028] The four-bar linkage 2 includes a first link 21, a second link 22, a third link 23, and a fourth link 24. It adopts the principle of a four-bar linkage and does not limit the shape of the specific components. For example, the links are not necessarily rod-shaped structures.

[0029] The four-bar linkage 2 is a parallelogram linkage mechanism. One end of the first link 21 is connected to the base 1, the second link 22 is connected to the gripper 3, the third link 23 has a hinge point with each of the first and second links 22, and the fourth link 24 has a hinge point with each of the first and second links 22. It can be understood that the third and fourth links 23 and 24 are transverse, while the first and second links 21 and 22 are longitudinal. The base 1 is a plate-like structure with through holes for connection, and is connected to the end of the robot arm by bolts. The first link 21 is formed from the first connecting plate and can be integrally formed with the base 1. The first link 21 can also be welded to the base 1, bolted, etc.

[0030] The second link 22 is formed by the second connecting plate. The third link 23 includes two parallel third connecting plates, which are located on both sides of the first link 21. The fourth link 24 includes two parallel fourth connecting plates, which are located on both sides of the first link 21. The use of paired connecting plates improves the stability of the linkage mechanism during operation. The four links form four hinge points, and a hinge pin 5 passes through each hinge point.

[0031] Each of the hinge points is provided with a bearing (inside, not shown), which is a miniature bearing, and each hinge pin 5 is provided with a pair of bearings, so that the rotation of the third link 23 relative to the first link 21 and the second link 22 is more flexible, more stable, and has low resistance and low wobbling.

[0032] The fourth link 24 has a connecting part for one end of the return spring 6 to be connected (the attached diagram is schematic; the two ends of the spring are not actually connected to the corresponding positions). A first hanging shaft 71 connects the two fourth connecting plates, forming the connecting part. A second hanging shaft 72 is provided on the base 1 for the other end of the return spring 6 to be connected. The return spring 6 is a tension spring. The first hanging shaft 71 and the second hanging shaft 72 can also be the hinge pins 5 described above.

[0033] The two extreme positions of the return spring 6 are defined as the first limit point 81 and the second limit point 82, respectively, at one end of the second link 22 and one end of the third link 23. During workpiece gripping, if a force is generated between the gripping rod 3 and the workpiece, the linkage mechanism activates, the return spring 6 is stretched, and the linkage mechanism moves to the first limit point 81, touching the base 1, at which point it cannot continue to compress upwards. After workpiece gripping is completed, the return spring 6 can return to its original position. During the return process, the maximum stroke is also limited; the linkage mechanism moves to the second limit point 82, touching the base 1, at which point it cannot continue to extend. Therefore, the relative range of motion between the gripping rod 3 and the base 1 is limited, sufficient to satisfy the buffering purpose during workpiece gripping. In actual use, not every workpiece experiences significant force with the gripping rod 3 during gripping. If the 3D camera 92 has high accuracy in recognizing the workpiece posture, the electromagnet 4 can be used to directly hold the workpiece. This linkage mechanism with buffering function also reduces the requirements for the 3D camera 92 to recognize the workpiece posture (allowing for a certain error in dimensional recognition in the Z-axis direction).

[0034] The electromagnet 4 has an arc-shaped groove 41 that adapts to the shape of the workpiece to be gripped and to the rod shape of the bolt to be gripped. The specific size of the arc-shaped groove 41 can be determined according to the bolt in the application scenario. The gripping rod 3 is an L-shaped rod, and the electromagnet 4 is bolted to the bend of the L-shaped rod, allowing for replacement of the gripping blocks. The cable of the electromagnet 4 can be routed along the gripping rod 3, running upwards.

[0035] The gripping rod 3 has several sequentially spaced connecting holes 31. The second connecting rod 22 is bolted to the gripping rod 3 and can selectively use the connecting holes 31 to adjust the distance between the electromagnet 4 and the base 1. A positioning groove is provided on one side of the gripping rod 3 for the second connecting rod 22 to slide and engage, ensuring the relative position of the second connecting rod 22 and the gripping rod 3 during assembly. In other embodiments, it can also be designed to be non-adjustable. In this case, the second connecting rod 22 and the gripping rod 3 can be bolted or welded together, or the second connecting rod 22 can be designed as part of the gripping rod 3, with both integrally formed.

[0036] When using the electromagnetic flexible clamp of this utility model:

[0037] Figure 3 As shown, the base 1 is connected to the robotic arm via bolts; in this embodiment, it is primarily mounted on the collaborative robot 91. The collaborative robot 91 is equipped with a 3D camera 92, which photographs the workpieces in the workpiece basket, identifies their posture and other parameters, and guides the robotic arm to grasp the workpiece at a designated coordinate point. The arc-shaped groove 41 of the electromagnet 4 is above the workpiece, moving downwards to contact and attract it, and then, under the action of the robotic arm, moves it to the designated position. Because it uses magnetic attraction, it avoids the problem of existing grippers lacking suitable gripping gaps in a pile of workpieces. During the gripping process, the four-bar linkage 2, in conjunction with the return spring 6, provides a certain degree of buffering, preventing hard collisions.

[0038] This novel electromagnetic flexible clamp has the following characteristics:

[0039] (1) Compared with the existing electric parallel gripper scheme, it avoids the problem that the gripper has no suitable gripping gap in the workpiece pile (the workpiece is in a disordered stacking state), which makes it convenient to grip.

[0040] (2) Lightweight, the connecting rod, base and gripper are all made of aluminum alloy, the structure is compact and small, the overall weight can be less than 0.5 kg, which can be adapted to collaborative robots with light loads;

[0041] (3) The structure is ingeniously designed. The upper and lower limits are directly utilized by the connecting rod and the base, without the need for additional limit components, which reduces the number of parts, facilitates processing and manufacturing, and reduces processing costs.

[0042] (4) The four-bar linkage, in conjunction with the spring, can effectively and reliably buffer the workpiece during the gripping process;

[0043] (5) When the base is in a horizontal state, the main body of the gripper (the longer section) has a certain tilt angle, which is more conducive to the robot arm gripping the workpiece.

[0044] (6) The hinge of the linkage mechanism is equipped with a high-precision bearing to ensure low resistance and low sway, and improve service life.

Claims

1. An electromagnetic flexible clamp, characterized in that: It includes a base for connecting to a robotic arm, the base being connected to a gripper via a four-bar linkage, the gripper having an electromagnet at its end; and a return spring between the four-bar linkage and the base.

2. The electromagnetic flexible clamp according to claim 1, characterized in that: The four-bar linkage includes a first link, a second link, a third link, and a fourth link. One end of the first link is connected to the base, the second link is connected to the grab bar, the third link has a hinge point with the first link and the second link, and the fourth link has a hinge point with the first link and the second link.

3. The electromagnetic flexible clamp according to claim 2, characterized in that: The fourth link has a connecting part for one end of the return spring to be connected.

4. The electromagnetic flexible clamp according to claim 3, characterized in that: The fourth link includes a pair of parallel fourth connecting plates, with a first hanging shaft connecting the two fourth connecting plates. The first hanging shaft forms the hanging part, and a second hanging shaft is provided on the base for connecting the other end of the return spring.

5. The electromagnetic flexible clamp according to claim 2, characterized in that: The first link is formed by a first connecting plate, the second link is formed by a second connecting plate, the third link includes two parallel third connecting plates, which are respectively located on both sides of the first link, and the fourth link includes two parallel fourth connecting plates, which are respectively located on both sides of the first link.

6. The electromagnetic flexible clamp according to claim 2, characterized in that: Each of the aforementioned hinge points is equipped with a bearing.

7. The electromagnetic flexible clamp according to claim 2, characterized in that: The gripper has several sequentially spaced connection holes. The second link is connected to the gripper by bolts and can selectively use the connection holes.

8. The electromagnetic flexible clamp according to claim 7, characterized in that: The gripper bar has a positioning groove on one side for the second link to slide and engage.

9. The electromagnetic flexible clamp according to claim 1, characterized in that: The electromagnet has an arc-shaped groove that is adapted to the shape of the workpiece to be gripped.

10. The electromagnetic flexible clamp according to claim 9, characterized in that: The gripper is an L-shaped rod, and the electromagnet is bolted to the bent section of the L-shaped rod.

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