WO2003101675A1

WO2003101675A1 - Flexible gripper apparatus with multiple gripping points for parts handling

Info

Publication number: WO2003101675A1
Application number: PCT/KR2002/001846
Authority: WO
Inventors: Mun Sang Kim; Yo Ha Hwang; Seung Jong Kim; Hyun Oh Shin; Jong Ryul Shin; Seung Jae Oh; Jeong Chan Lim; Sung Kee Park; Jonk Suk Choi
Original assignee: Korea Institute Of Science And Technologie
Priority date: 2002-06-04
Filing date: 2002-10-04
Publication date: 2003-12-11
Also published as: AU2002353541A1; KR100500974B1; KR20030093662A

Abstract

The present invention presents a flexible gripper apparatus with multiple gripping points for parts handling, installed at loader/unloader of a robot or a press with a state that the gripper locations of the gripping apparatus can be moved into arbitrary three dimensional locations, that changes the locations of gripping points according to the size and the shape of an object part and performs repetitive operations continually with fixing the locations thereat. Consequently, a flexible gripper apparatus with multiple gripping points for parts handling, of which. each gripping point can be operated independently or some gripping points are linked to be operated to control the gripping locations in three-dimensional space, controls the gripper locations by manual operation and/or by a pre-inputted program according to the size and the shape of an object part when an object part is being changed.

Description

FLEXIBLE GRIPPER APPARATUS WITH MULTIPLE GRIPPING POINTS FOR PARTS HANDLING

[Technical Field]

The present invention relates to a flexible gripper apparatus with multiple gripping points for parts handling, and more particularly to a flexible gripper apparatus for parts handling, whose shape is automatically being modified to fit for an object part by an operator control and/or a control signal when the object part is changed, able to handle various shapes of parts in a conventional loader/unloader system. The present invention also relates to a flexible gripper apparatus for parts handling that can modify the shape of jig for fixing parts to fit for various shapes of parts when an operation is finished for a part or waiting for next operation.

[Background Art]

In a press operation for mass production used in automobile factory, it generally uses a loader and a gripping apparatus equipped thereat to grip a part outside of a press, and thereafter moves the part between the upper and lower molds of a press to load it on the lower mold of the press. Then, a press operation is performed while the loader returns to its original position to grip next part, and an unloader and a gripping apparatus equipped thereat unloads the part after being pressed.

Here, the loader/unloader generally shows a two- dimensional movement. That is to say, it moves up/down to grip a part and left /right (or front/back) to load(or unload) the part into(or out of) the press. A main boom is generally equipped at the end of the loader/unloader, and various shapes of attachments are installed at the main boom according to the object parts.

Since the object parts have three-dimensional shapes of various sizes, attachments generally have complex shapes like an antler for gripping these parts. That is, attachments have various structures according to the sizes and shapes of object parts, and in general, numbers of vacuum cups are installed thereat to grip the object parts. In case of a small part, one or two vacuum cups are used, however, in case of a large-size part having a complex shape, a large number of vacuum cups are used. For example, looking into a conventional press operation as described in FIG. 1, a loader(lθ) is equipped with a main boom(12) at an end, and an attachment ( 16) having four vacuum cups (14a, 14b, 14c, 14d) is installed at the boom(12) to move a part to a press .

Here, in case that the part has a large size and a complex shape, the shape of an attachment ( 16 ) becomes to be complicated in three dimension like an antler, and in addition, some of the vacuum cups (14a, 14b, 14c, 14d) installed thereat have angles to the right/left directions while the others to the up/down directions. As mentioned before, only one or two vacuum cups can be used for a case of a small part, however, a large number of vacuum cups have to be used for a case of a large-size part having a complex shape.

Generally, 5~6 presses are serially arranged to perform a press operation in a factory for multi-kind mass production like that of an automobile company, and each press is equipped a separate loader/unloader. Since the shape of a part is being changed as the operation is being carried out by each press, the shape of an attachment installed at each loader/unloader is different from one another. In addition, molds are frequently exchanged during the operation since various kinds of products are to be processed. At this time, an attachment manufactured to fit for each mold is exchanged together. Besides, even the parts for a vehicle of terminated model have to be produced for after-service, and thus the number of attachments to be prepared and maintained near to a press becomes to be largely increased.

By the way, it decreases the overall production efficiency to manufacture, maintain, repair and frequently exchange these various attachments. Besides, the production cost gets increased, and a large storing space is required for storing these attachments near to a press for fast exchange.

It also requires much time and cost to maintain and repair the apparatus, such as to exchange the defective units like damaged vacuum cups frequently occurring in numbers of attachments, to maintain the preset angles of vacuum cups, and so forth.

Meanwhile, a part unloaded from a press by an unloader is moved into a predetermined stand-by location to be gripped by the loader of next press for being loaded into next press, or it is being laid on a transfer device that rotates the part to change the direction for an operation of next press or moves the part into a location where the next loader can grip it easily .

At this time, due to the various sizes and shapes of parts, a jig with an appropriate shape has to be set at each stand-by location or on each transfer device. A jig is usually fixed at a certain location on a base frame having many holes, however, the operation flexibility is degraded due to the fixed hole locations and thus numbers of jigs with various shapes have to be prepared. Besides, these jigs also have to be manually exchanged at the time of mold exchange, and thus it decreases the overall productivity.

[Disclosure of Invention]

The present invention is proposed to solve the problems of the prior art mentioned above. It is therefore the object of the present invention to provide a flexible gripper apparatus with multiple gripping points for parts handling of which each gripping point can be operated independently or some gripping points are linked to be operated to control the gripping locations in three-dimensional space.

It is another object of the present invention to provide a flexible gripper apparatus for parts handling that controls the gripper locations by manual operation and/or automatically controls them by a pre- inputted program according to the size and the shape of an object part when an object part is being changed. To achieve the object mentioned above, the present invention presents a flexible gripper apparatus for parts handling, which requires a separate gripping attachment for each object part to grip the part in a mechanical apparatus performing a large number identical repetitive operations during which the object parts are changed frequently, characterized by comprising at least one gripping apparatus, installed at loader/unloader of a robot or a press with a state that the locations at which the grippers of the gripping apparatus are to be installed can be moved into arbitrary locations set by a program in three- dimensional space, that changes the locations of gripping points according to the size and the shape of an object part and performs repetitive operations continually with fixing the locations thereat. The main design point of the present invention is to reduce the total exchange time by automatically finishing a gripper setting during a mold exchange operation of a press as well as to maintain the overall strength of a loader/unloader with lightening the weight of the loader/unloader as much as possible to reduce the load.

For this purpose, we set a setting time as long as possible within a mold exchange operation time to minimize the motor output by maximizing the overall deceleration ratio and thereby to reduce the size and weight of a motor, and designed the guides, used for actuating the motor, to take an important part in overall strength. In addition, considering that the overall system size has to be smaller than the minimum distance between the upper and lower molds in a press operation and the loader/unloader is frequently moving into the gap between the molds before the upper mold reaches the top position for increasing the operation speed in an actual operation, the height of an overall system needs to be minimized.

[Brief Description of Drawings]

FIG. 1 is a view illustrating an example of a prior press operation. FIG. 2 is a view illustrating the basic structure of a flexible gripper apparatus for parts handling in accordance with the present invention. FIG. 3 ~ FIG. 8 are views illustrating various embodiments of flexible gripper apparatus for parts handling in accordance with the present invention.

FIG. 9 is a view illustrating an example of an actual loading operation for a part in accordance with the present invention.

FIG. 10 is a view illustrating an example of a jig having flanges for fixing parts on an apparatus unit moving on a two-dimensional plane in accordance with the present invention.

FIG. 11 is a view illustrating an example of a jig at which various branches are installed with different angles in accordance with the present invention.

[Best Mode for Carrying Out the Invention^

Hereinafter, referring to appended drawings, the structures 'and the operation procedures of the embodiments of the present invention are described in detail . FIG. 2 is a view illustrating the basic structure of a flexible gripper apparatus for parts handling in accordance with the present invention. FIG. 3 ~ FIG. 8 are views illustrating various embodiments of flexible gripper apparatus for parts handling in accordance with the present invention. FIG. 9 is a view illustrating an example of an actual loading operation for a part in accordance with the present invention. FIG. 10 is a view illustrating an example of a jig having flanges for fixing parts on an apparatus unit moving on a two-dimensional plane in accordance with - the present invention. FIG. 11 is a view illustrating an example of a jig at which various branches are installed with different angles in accordance with the present invention. For improving the prior attachment structure, the present invention adopts an attachment structure whose shape can be changed with numbers of vacuum cups or electromagnets installed thereat. That is to say, it changes the structure flexibly according to the size and shape of an object part into a pre-programmed optimized shape and actuates necessary numbers of vacuum cups (or electromagnets) to carry out a gripping operation for the object part. To perform a gripping operation as described above, vacuum cups are structured to be independent of one another, or some of them are linked together, and located in three-dimensional space. Each Vacuum cup has a structure of manual rotation being possible like a ball-socket structure, and thus it can handle the inclination of an object part surface, when the inclination is not so large, by using ball-socket joint rotation when contacting the part.

Additionally, for the case that the inclination of a gripping surface of an object part is relatively large or for any cases necessary, vacuum cups are designed to have a structure of biaxial rotation being possible. With this structure, one can rotate it using a control signal, fix the rotated shape, and perform an operation thereafter. As described in FIG. 2, a basic structure of an attachment as described above has a structure in which a vacuum cup (26) having a degree of freedom into vertical direction is combined with a horizontally moving axial structure (a first axial unit (20) and a second axial unit (22)) like a three-axis unit (24). Thus, an attachment has a shape of comprising these basic structure units as many as the number of vacuum cups (26), and in addition, a vacuum cup (26) has a structure of rotational movement being possible with 2 degrees of freedom for appropriately handling the surface inclination of an object part.

Based on the basic structure ( FIG . 2) of a flexible gripper apparatus for parts handling as described above, the methods of adding a horizontal movement of 2 degrees of freedom ( e . g . , a first axis and a second axis) can be achieved by various structures.

Hereinafter, various embodiments (embodimentl embodimentδ) of the present invention are described referring to the drawing of FIG. 3 ~ FIG. 8.

[Embodiment 1]

As described in FIG. 3, it has a structure of combining a unit linearly moving along with a first axis with a unit linearly moving along with a second axis. Numbers of second axial units can be combined with a first axial unit for system expansion, and the combining direction can be freely set to the upper or lower direction in the figure.

[Embodiment 2]

For more simplifying the attachment structure by using the basic structure described in FIG 3, a structure in which two second axes are linked to be combined to a first axis as shown in FIG. 4. In this case, the motion of vacuum cup is partially limited due to the limitation in degrees of freedom, however, it can be more efficient in some cases according to the shape of an object part.

[Embodiment 3] As described in FIG. 5, two or more axes of FIG. 3 or FIG. 4 can be connected in parallel^' to expand the operation area.

[Embodiment 4]

Since the structure of using a first and a second axes is moving on a two-dimensional plane, it can be also structured as described in FIG. 6(a) ~ FIG. 6(c) by using two or more rotational joints for setting an arbitrary position on a plane. With this structure, it can be connected to additional booms as many as the number of vertical units as described in the figures, and the connections can be made at one point or at various points.

[Embodiment 5]

As described in FIG. 7, it can be structured to be a linear unit in a first axial direction with being connected to a boom using a rotational joint. In this case, numbers of linear units can be installed in a first axis, or numbers of first axes can also be connected to a boom similar to FIG. 6(b) and FIG. 6(c).

[Embodiment 6] A structure of having a first axis connected to a boom and numbers of second axes connected to the first axis by rotational joints is also possible as described in FIG. 8(a) ~ FIG. 8(c) . In this case, second axes can have either rotational joint structure or linear unit structure for increasing the degree of freedom of an operation.

Here, the movements of the first and second axes are horizontal, however, a general operation of handling parts, rather than a press operation, does not strictly limits using the upper/lower space. And thus, it can be moved up and down by using a rotational joint like an insect leg, and at the same time, it can also be rotated horizontally at the location connected to a main boom.

In an apparatus for loading parts, an object part is laid on a jig(30) of a table as described in FIG. 9, and various jigs (32) are standing by for other operations thereunder. As shown in FIG. 10, the present invention installs a jig with flanges for fixing parts on an apparatus ^• moving two-dimensionally like an X-Y table, and locates the jig to fit for the size of an object part by two-dimensional movement. At this time, the shape adaptation for a part can be easily achieved by moving a jig up and down or using numbers of flanges. Furthermore, by installing various branches with different angles at a jig as described in FIG. 11, for example designing a jig rotating every 90°, it can be adapted more easily for various shapes of object parts. _t

Since those having ordinary knowledge and skill in the art of the present invention will recognize additional modifications and applications within the scope thereof, the present invention is not limited to the embodiments and drawings described above.

[Industrial Applicability]

As mentioned thereinbefore, a flexible gripper apparatus with multiple gripping points for parts handling in accordance with the present invention, of which each gripping point can be operated independently or some gripping points are linked to be operated to control the gripping locations in three- dimensional space, controls the gripper locations by manual operation and/or automatically controls them by a pre-inputted program according to the size and the shape of an object part when an object part is being changed, and thereby makes it possible to use only one gripper system for each loader/unloader to reduce the time and labor cost required for an attachment exchanging operation. In addition, it also reduces the cost for an attachment production/maintenance/repair, minimizes the storing space around a press, and flexibly responds to various products including current products as well as parts of terminated models for after-service.

Besides, even for producing a new-born product, it can increase the overall system efficiency and reduce the 'production cost considerably by providing an immediate response with pre-programming for the product. Moreover, by introducing a jig whose shape is automatically being changed to fit for an object part at stand-by location, a part is laid thereon between press operations, it can handle all the parts with only one system.

Claims

WHAT IS CLAIMED IS:

1. A flexible gripper apparatus for parts handling, which requires a separate gripping attachment for each object part to grip the part in a mechanical apparatus performing a large number of identical repetitive operations during which the object parts are changed frequently, characterized by comprising at least one gripping apparatus, installed at loader/unloader of a robot or a press with a state that the locations at which the grippers of said gripping apparatus are to be installed can be moved into arbitrary locations set by a program in three dimensional space, that changes the locations of gripping points according to the size and the shape of an object part and performs repetitive operations continually with fixing the locations thereat.-

2. A flexible gripper apparatus for parts handling s claimed in claim 1, characterized in that vacuum cups or electromagnets are used for said gripping apparatus.

3. A flexible gripper apparatus for parts handling as claimed in claim 1, characterized in that, when an object part is laid on a jig at stand-by location after an operation, said jig is controlled to be automatically moved on a horizontal plane into an appropriate location to fit for the shape of said object part.

4. A flexible gripper apparatus for parts handling as claimed in claim 3, characterized in that numbers of flanges are installed at said jig in the direction to an object part to control the plane location, where said object part is to be located, according to the size and shape of said object part.

5. A flexible gripper apparatus for parts handling as claimed in claim 3, characterized in that said jig has a rotational degree of freedom and numbers of flanges installed at said jig to various directions can move horizontally and rotationally .

6. A flexible gripper apparatus for parts handling comprising numbers of first, second, and third axial units, wherein said first, second, and third axial units can afford independent linear movements respectively, and at least two gripper units, a vacuum cup is installed at each of said units, are installed at an end of each of said third axial units, and thereby the locations of said vacuum cups can be controlled independently of partially linked in a three-dimensional space.

7. A flexible gripper apparatus for parts handling claimed in claim 6, characterized in that the connecting directions of said units can be freely set to the upper direction or to the lower direction.

8. A flexible gripper apparatus for parts handling claimed in claim 6, characterized in that each of said first axial unit has two or more transfer sectors at each of which two second axial units are installed, and said vacuum cups can be independently located in a three-dimensional space.

9. A flexible gripper apparatus for parts handling claimed in claim 8, characterized in that the numbers of said transfer sectors of said first axial units are different from one another and the end portions of said first axial units are formed to be connectable to one point or more.

10. A flexible gripper apparatus for parts handling claimed in claim 6, characterized by comprising two or more structures, connected in parallel, each of which comprises said first axial unit linearly moving along with a first axis and said second axial unit, connected to said first axial unit, linearly moving along with a second axis .