KR102311068B1 - Gripper structure of robot arm with push function for workpiece - Google Patents

Abstract

The present invention relates to a gripper structure which is provided on an end of a robot arm including a plurality of joint arms and rotating arms, and grips a workpiece. Provided is a gripper structure of a robot arm having a push function for a workpiece. The gripper structure includes: a body (10) in which a pneumatic cylinder is built; a pair of left and right fingers (20) positioned at the central portion of an upper side of the body (10) to be spaced apart from each other by a certain distance and disposed to face each other; an operation plate (31) located to be spaced apart from an upper side portion of the body (10) by a predetermined distance in a vertical and upward direction; a first mill pin (32) with each lower end portion fixed and coupled to each edge portion at an upper side of the body (10), each upper end portion extending, penetrating and coupled to each edge portion of the operation plate (31); a first coil spring (33) with a spring constant of k1, and having a lower end portion attached to each edge portion at the upper side of the body (10) and each upper end portion attached to each edge portion at the lower surface of the operation plate (31) so as to surround each first mill pin (32); an operation cap (34) positioned to be spaced apart from the central portion at the upper side of the operation plate (31) by a predetermined distance in a vertical and upward direction; a second mill pin (35) with a lower end portion penetrating and coupled to a central portion of the operatin plate (31) and an upper end portion fixed and coupled to a lower surface portion at the center of the operation cap (34); and a second coil spring (36) with a spring constant of k2 (k1 〉k2) and having a lower end portion attached to the central portion at the upper side of the operation plate (31) and an upper end portion attached to a lower surface portion at the center of the operation cap (34) so as to surround the second mill pin (35).

Description

Gripper structure of robot arm with push function for workpiece

The present invention relates to a gripper structure of a robot arm, and more specifically, it is possible to maintain a very stable gripping state even if the workpiece has a diameter in a variety of ranges, and to maximize the gripping force regardless of the state of the cut surface of the workpiece. It relates to a gripper structure of a robot arm that is provided with a push function for a workpiece capable of being processed.

A computer numerical control machine tool is a machine that processes a material into an intended shape according to an input program. The material is fixed to a chuck and then rotates with the chuck as a tool. In most cases, a robot is used to supply a material to such a computer numerically controlled machine tool and to recover the processed material.

A general robot responsible for supply and recovery of material is provided with a plurality of articulation arms 12 and a rotary arm 13 as shown in FIG. 5A, and the rotary arm 13 has a gripper 31 capable of gripping the material; 51) is provided. Among the grippers provided in the rotary arm 13 , a configuration in which a push pin 44 and a coil spring 42 are provided on the movable plate 41 as shown in FIG. 5B has also been proposed.

In this case, when one end of the workpiece is gripped by the finger 34 while pressing the movable plate 41 , and then the workpiece is released from the grip of the finger 34 , the workpiece is generated by the restoring force of the coil spring 42 . is pushed with a certain force, the workpiece is pushed in the direction of the central axis of the chuck (not shown), and the chuck stably grips the other end of the workpiece, so that machining is performed by the tool.

However, since this technology uses a coil spring having a single value of spring constant, if the workpiece is not gripped with a value larger than the spring constant of the coil spring per unit length, restoring force by the coil spring can be expected. can't Therefore, the end of the robot arm must be gripped while pressing one end of the workpiece with a certain force or more. In the case of a workpiece with a small diameter, there is a possibility that one end of the workpiece may be damaged.

In addition, most of the processed materials cut the round bar by a certain length and use it, but in reality, it is very difficult to perform the cutting operation so that the cut surface is accurately vertical. In this case, there is a limit that the push function of the movable plate cannot be used properly because the adhesion between the movable plate or the pressing end and the workpiece provided in the gripper is significantly lowered, especially when the surface of the cut surface is rough and not smooth.

Republic of Korea Patent No. 2055601

The present invention has been proposed to improve the problems of the prior art, and an object of the present invention is a gripper structure of a robot arm that can easily push the workpiece in the direction of the central axis of the chuck regardless of the diameter or state of the cut surface of the workpiece. is to provide.

In order to achieve this object, the present invention provides a gripper structure provided at the end of a robot arm comprising a plurality of articulated arms and a rotating arm to grip a workpiece, the body 10 having a built-in pneumatic cylinder; Fingers 20 located in the upper central portion of the body 10 made of a pair of left and right opposite each other spaced apart from each other; The upper part of the body 10 is a movable plate 31 positioned a certain distance vertically upward, and each lower part is fixedly coupled to each upper edge part of the body 10, and each upper part extending is a movable plate 31 ) has a first mil pin 32 coupled through each of the corners, and has a spring constant k1, and each lower end is in close contact with each of the upper corners of the body 10, and each upper end of the movable plate 31 The first coil spring 33, which is in close contact with each of the lower surface corners and surrounds each of the first push pins 32, the movable cap 34, which is positioned vertically upwardly spaced apart from the upper central portion of the movable plate 31 by a predetermined interval, the lower portion has a second push pin 35, a spring constant k2 (k1 > k2) that is coupled through the central portion of the movable plate 31 and the upper portion is fixedly coupled to the central lower surface of the movable cap 34, and the lower portion is The second coil spring 36 is in close contact with the upper central portion of the movable plate 31 and the upper portion is in close contact with the central lower surface of the movable cap 34 to surround the second push pin 35; have.

A plurality of contact surfaces 341 , 343 , 345 having the same diameter but having different vertical depths may be formed on the upper surface of the movable cap 34 .

In this case, a plurality of concavo-convex portions 342 , 344 , 346 may be formed on each of the contact surfaces 341 , 343 , and 345 .

In the present invention, by arranging coil springs having different spring constant values in the portion where the end of the workpiece contacts in gripping the workpiece, the coil springs can be sequentially compressed by the applied pressing force. Even with a wide range of diameters, it is possible to maintain a very stable gripping state without damaging the ends.

In addition, the present invention can be applied to processed materials having various diameters with one movable cap without a separate replacement operation by forming a plurality of contact surfaces with different depths on the upper surface of the movable cap to which the processed material is closely adhered, By proposing a configuration in which a plurality of concavo-convex portions are formed on each of the contact surfaces, it is possible to maximize the degree of adhesion between one end of the workpiece and the upper surface of the movable cap regardless of the state of the cut surface of the workpiece.

1 is a schematic isometric configuration diagram of a robot arm gripper according to the present invention.
2A and 2B are a schematic front view and a side view of a robot arm gripper according to the present invention.
3A and 3B are schematic isometric and cross-sectional views of the movable cap in the gripper of the robot arm according to the present invention.
4A to 4G are each a schematic operation configuration diagram of a robot arm gripper according to the present invention.
5A is a schematic configuration diagram of a robot provided with a conventional gripper;
Fig. 5B is a schematic configuration diagram of the gripper in Fig. 5A;

A preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings as follows. In the description of the embodiments of the present invention, there is no direct relation to the technical features of the present invention, or it is common in the technical field to which the present invention pertains. For matters that are obvious to those with the knowledge of

The present invention provides a gripper structure provided at the end of a robot arm, including a body 10, a finger 20, a movable plate 31 and a movable cap 34, first and second mil pins 32, 35, first, It is characterized by including two coil springs (33, 36). Hereinafter, each of these configurations will be described in detail.

The robot arm consists of a plurality of articulated arms and a rotating arm. The joint arm is a part that connects the joints to each other, and the rotary arm is provided at the end of the joint arm. In the present invention, the robot arm may be made of any one of the robot arms generally used in the related industry as shown in FIG. 5A.

The body 10 has a built-in pneumatic cylinder and is coupled to a rotating arm (not shown). A separate plate for coupling the body 10 may be provided in the rotary arm. A diaphragm or piston operating in one direction or the other depending on the air supplied to the inlet 13 or discharged to the outlet 11 may be provided inside the pneumatic cylinder. The configuration and operation of such a pneumatic cylinder is widely known in the related art, and detailed description thereof will be omitted.

The fingers 20 are a part for gripping the processed material, and are made of a pair of left and right opposite each other spaced apart from each other at a predetermined distance, and are located in the upper central portion of the body 10 . A gripping groove may be formed in the finger 20 as shown in FIG. 1 , and the finger 20 is operated by the above-described pneumatic cylinder.

The movable plate 31 is positioned vertically upward at a predetermined distance from the upper portion of the body 10, as shown in FIGS. 2A and 2B, respectively. The first push pin 32 is provided at each corner of the movable plate 31 , and each lower end is fixedly coupled to each of the upper corner of the body 10 , and each extending upper end is the movable plate 31 . ) penetrates through each of the corners and is combined.

At this time, it is preferable that the through hole of the movable plate 31 through which the upper end of the first mil pin 32 penetrates is formed to be larger than the diameter of the first mil pin 32 . Accordingly, the movable plate 31 can be vertically raised and lowered by a predetermined distance through the upper portion of the first push pin 32 as shown in FIG. 4C .

The first coil spring 33 has a spring constant k1, and each lower end is in close contact with each of the upper corners of the body 10, and each upper end is in close contact with each of the lower corners of the movable plate 31. Each of the first push pins 32 is wrapped.

The movable cap 34 is a portion to which one end of the processed material is in close contact, and is positioned vertically upward at a predetermined interval from the upper central portion of the movable plate 31 . The lower end of the second push pin 35 is coupled through the central portion of the movable plate 31 , and the upper end thereof is fixedly coupled to the central lower surface of the movable cap 34 .

At this time, it is preferable that the through hole of the movable plate 31 through which the lower end of the second mil pin 35 penetrates is formed to be larger than the diameter of the second mil pin 35 . Accordingly, unlike the movable plate 31 , the movable cap 34 can ascend and descend by a predetermined distance vertically through the lower portion of the second push pin 35 as shown in FIG. 4B .

The second coil spring 36 has a spring constant k2, and its lower end is in close contact with the upper central portion of the movable plate 31, and its upper end is in close contact with the central lower surface of the movable cap 34, so that the second mil pin wrap (35).

At this time, the spring constant k2 of the second coil spring 36 has a smaller value than the spring constant k1 of the first coil spring 33 . That is, in the present invention, each of the first and second coil springs 33 and 36 is configured to have k1 > k2.

As in the present invention, the first and second coil springs 33 and 36 having different spring constants are provided on the movable plate 31, but the spring constant is relatively small to the movable cap 34 to which one end of the workpiece is in close contact. By providing the second coil spring 36 having

Meanwhile, the present invention proposes a case in which a plurality of contact surfaces 341 , 343 , 345 are formed on the upper surface of the movable cap 34 , as disclosed in FIGS. 2A and 2B , respectively. At this time, the contact surfaces 341 , 343 , and 345 are each formed to have the same diameter, each of which has a different vertical depth, and is preferably configured to have a smaller diameter toward the center.

The upper surface portion of the movable cap 34 is a portion to which one end of the processed material is in close contact. When one end of the processed material is in close contact with the upper surface of the movable cap 34 , the central axis of the processed material is moved by the finger 20 . aligned with the central axis of the cap 34 . The central axis of the chuck is not shown by the restoring force of the first coil spring 33 or the first and second coil springs 33 and 36 when the central axis of the workpiece is precisely aligned with the central axis of the movable cap 34 . direction is transmitted accurately.

However, the alignment of the central axis of the workpiece by the finger 20 has a practically certain limit. To this end, in the present invention, by forming different contact surfaces 341, 343, 345 corresponding to the diameter of the workpiece on the upper surface of the movable cap 34, the central axis of each of the workpieces having different diameters is the movable cap. (34) can be more precisely aligned with the central axis.

In addition, if a plurality of contact surfaces having different diameters are formed on the upper surface of the movable cap 34, the single movable cap 34 can be applied to processed materials having various diameters. After preparing a plurality of movable caps 34 corresponding to the diameter of , it is possible to prevent in advance the hassle of having to replace the movable caps 34 one by one whenever the diameter of the workpiece changes.

In this case, a plurality of concavo-convex portions 342 , 344 , 346 may be further formed on each of the contact surfaces 341 , 343 , and 345 . According to the present invention, the concavo-convex portions 342 , 344 , 346 formed on each of the plurality of contact surfaces 341 , 343 , 345 may have an annular groove shape as shown in the drawings.

The processed material is used by cutting the round bar by a certain length, but the cut surface does not form an accurate vertical state and the surface state is also not smooth. not closely adhered to

In this case, when the concave-convex portions 342 , 344 , 346 are formed on the upper surface of the movable cap 34 in contact with one end of the processed material as in the present invention, one end of the processed material and the upper surface of the movable cap 34 . In that the contact area between the areas can be expanded, it is possible to maximize the push function by the restoring force of each of the first and second coil springs 33 and 36 .

The schematic operation of the present invention having such a configuration will be looked at with reference to the above description and the accompanying drawings.

The robot arm is activated to move the arm end to the point where the workpiece is loaded. When the end of the arm moves to the point where the workpiece is loaded, the rotating arm is rotated at a certain angle to align the central axis of the gripper with the central axis of the workpiece, and then, as shown in FIG. ) to descend. At this time, the fingers 20 are opened left and right due to the operation of the pneumatic pressure.

When the gripper descends while the fingers 20 are open, one end of the workpiece P passes through the space between the fingers 20 and comes into contact with the upper surface of the movable cap 34 . In this state, if the gripper descends a little further, the spring constant of each of the first and second coil springs 33 and 36 has a relationship of k1 > k2, ) compresses the second coil spring 36 and moves the movable cap 34 vertically.

When the gripper descends a little while the one end portion of the processed material P moves while compressing the second coil spring 36, the pressing plate 31 is operated by the first coil spring ( 33) and move further vertically. Accordingly, one end portion of the processing material (P) forms a state in close contact with the upper surface portion of the movable cap (34). Of course, when a contact surface or an uneven portion is formed on the upper side of the movable cap 34, the degree of adhesion may be further increased.

When one end of the workpiece (P) is in close contact with the upper surface of the movable cap 34 by the resultant force f1 + f2, the finger 20 is closed as shown in FIG. Grab it. When the workpiece P is gripped by the finger 20, the robot arm operates to move the arm end to the point where the chuck is located inside the computer numerical control machine tool (not shown), and then the central axis of the workpiece P Align it so that it coincides with the central axis of this chuck.

When the central axis of the workpiece P coincides with the central axis of the chuck, the finger 20 is opened as shown in FIG. 4E while the air pressure is operated again. When the finger 20 holding the workpiece P is opened, the restoring force of the first coil spring 33 compressed by the movable plate 31 due to the relative value of the spring constant in the relationship k1 > k2 While -f2 operates, the movable plate 31 is vertically pushed as shown in FIG. 4f.

Then, the restoring force -f1 of the second coil spring 36 compressed by the movable cap 34 then operates to further push the movable cap 34 vertically. Accordingly, the processed material P is pushed in the direction of the central axis of the chuck (not shown) while being pushed by the restoring force (-f1) + (-f2) resultant force of the first and second coil springs 33 and 36 as shown in FIG. 4G . When one end of the workpiece (P) is in close contact with the central axis of the chuck aligned, the chuck is operated to grip the workpiece (P).

After that, when the robot arm operates and the gripper is removed from the computer numerically controlled machine tool, the machine tool performs the work on the workpiece P using the tool according to the input program sequence, and when the work by the tool is completed The robot arm operates again to take out the finished part from the computer numerically controlled machine tool to complete the machining operation on the material.

In the above description, the preferred embodiments of the present invention are limited, but this is only an example, and the present invention is not limited thereto and can be changed and implemented in various ways, and further, separate technical features are provided based on the disclosed technical idea. It will be obvious that it can be implemented in addition.

10: body 20: finger
31: movable plate 32: first mil pin
33: first coil spring 34: movable cap
35: second mil pin 36: second coil spring
341, 343, 345: contact surface 342, 344, 346: uneven part

Claims (3)

A gripper structure provided at an end of a robot arm comprising a plurality of articulated arms and a rotating arm to grip a processed material, the gripper structure comprising:
a body 10 having a built-in pneumatic cylinder;
Fingers 20 located in the upper central portion of the body 10, consisting of a pair of left and right opposite each other spaced apart from each other;
The upper part of the body 10 is a movable plate 31 positioned vertically upward a certain distance apart, and each lower part is fixedly coupled to each upper edge part of the body 10 and each extended upper part is a movable plate 31 . ) has a first mil pin 32 coupled through each of the corners, a spring constant k1, and each lower end is in close contact with each of the upper corners of the body 10, and each upper end of the movable plate 31 The first coil spring 33, which is in close contact with each of the lower surface corners and surrounds each of the first push pins 32, the movable cap 34, which is located vertically upwardly spaced apart from the upper central portion of the movable plate 31 at regular intervals, the lower portion has a second push pin 35, a spring constant k2 (k1 > k2) that is coupled through the central portion of the movable plate 31 and the upper portion is fixedly coupled to the central lower surface of the movable cap 34, and the lower portion is The second coil spring 36 is in close contact with the upper central portion of the movable plate 31 and the upper portion is in close contact with the central lower surface of the movable cap 34 to surround the second push pin 35;
A gripper structure of a robot arm provided with a push function for a workpiece containing it. According to claim 1,
A gripper of a robot arm provided with a push function for a workpiece, characterized in that a plurality of contact surfaces (341, 343, 345) having the same diameter but having different vertical depths are formed on the upper surface of the movable cap (34) structure. 3. The method of claim 2,
A gripper structure of a robot arm provided with a push function for a workpiece, characterized in that a plurality of concavo-convex portions (342, 344, 346) are formed on each of the contact surfaces (341, 343, 345).

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