Data processing: generic control systems or specific application – Specific application – apparatus or process – Robot control
Reexamination Certificate
2000-07-21
2001-12-25
Cuchlinski, Jr., William A (Department: 3661)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Robot control
C414S731000, C414S735000, C414S733000, C249S066100, C249S073000, C074S490030, C901S023000
Reexamination Certificate
active
06334078
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a robot for a production machine which is used as a product removal apparatus for removing products from a production machine such as an injection molding machine, or as an insert-part-loading apparatus for loading an insert part into a mold.
2. Description of the Relevant Art
There has been known a product removal apparatus (robot for a production machine) which is added to an injection molding machine and which removes a product ejected from a mold by an ejector and transports the removed product to a product stocker (shooter) disposed adjacent to the injection molding machine.
A conventionally-used product removal apparatus is a traverse-type product removal apparatus which is designed to move linearly a chuck capable of holding and releasing a product along X, Y, and Z directions. However, one drawback of such a traverse-type product removal apparatus is that since the apparatus must have a size corresponding to the stroke of movement of the chuck along each direction, the apparatus is comparatively large overall, and an installation space corresponding to the stroke of movement is required.
In order to solve the above-described drawback, Japanese Utility Model Publication Nos. 4 (1992)-45861, 5 (1993)-40989, and others propose an improved product removal apparatus in which an articulated robot having a plurality of linked arm portions is used in order to reduce movement area to thereby reduce the size and installation space.
Meanwhile, a mold clamp apparatus of an injection molding machine includes four tie bars, which slidably support a movable platen to which is attached a movable mold. Therefore, a molded product must be removed through a space between the tie bars without causing interference with the tie bars. Accordingly, the chuck of a product removal apparatus must be moved linearly at least along the vertical direction, and the chuck must be maintained in a constant posture (orientation). In the case of the above-described articulated robot, since fundamental motions are produced by means of rotation of respective joint portions, when the chuck is to be moved linearly, two arm portions must be moved in a combined manner through simultaneous control of rotational angles of the two arm portions.
However, when a chuck is secured to a distal end of an articulated arm, the orientation of the chuck changes depending on the rotational angles of the arm portions. Therefore, the conventional product removal apparatus of the articulated robot type which has been provided in injection molding machines requires an additional drive mechanism for correcting the orientation of the chuck. This results in an increase in the number of parts, an increase in difficulty in designing a control system, and an increase in cost stemming from an increased degree of complexity of hardware and software. Further, the overall size and weight of the product removal apparatus increase. In particular, the conventional product removal apparatus requires a large space in the vertical direction and cannot increase the product removal speed.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a robot for a production machine which is advantageously disposed in an injection molding machine and which can stably and smoothly remove a molded product through a space between tie bars without causing interference with the tie bars, even when the molded product is large.
Another object of the present invention is to provide a robot for a production machine which can simplify the mechanical system and the control system to thereby greatly reduce the overall cost of the apparatus, as well as the size and weight of the apparatus.
Still another object of the present invention is to provide a robot for a production machine which can reduce a space required in the vertical direction and increase operation speed such as product removal speed.
To achieve the objects, the present invention provides a robot for a production machine (a product removal apparatus or an insert-part-loading apparatus) comprising: a parallel link mechanism including opposed first and second shorter-side links and opposed first and second longer-side links which form a parallelogram; a chuck supported on the first shorter-side link; a guide rail fixed to a base arm and movably supporting the second shorter-side link; a drive link having a base end rotatably attached to the base arm and a distal end rotatably attached to an intermediate portion of one of the first and second longer-side links; and a drive mechanism for rotating the base end of the drive link.
By virtue of the above-structure, when the base end of the drive link is rotated by the drive mechanism, the second shorter-side link moves along the guide rail, and the first shorter-side link moves in a direction perpendicular to the direction of movement of the second shorter-side link. When the length of the longer-side links is set to two times the length of the drive link, and the distal end of the drive link is coupled to the center portion of one of the longer-side links, the first shorter-side link moves linearly or straight in the direction perpendicular to the direction of movement of the second shorter-side link. Further, since the chuck is supported on the first shorter-side link of the parallel link mechanism, the orientation (posture) of the chuck is maintained constant.
REFERENCES:
patent: 4795124 (1989-01-01), Nagai
patent: 4813846 (1989-03-01), Helms
patent: 4901589 (1990-02-01), Gaigl
patent: 4947702 (1990-08-01), Kato
patent: 5106258 (1992-04-01), Orii
patent: 5197846 (1993-03-01), Uno et al.
patent: Y2-445861 (1992-10-01), None
Carter et al., Applocation of Universal Adaptive Control to a Two Link Robot, 1989, IEEE, pp. 642-645*.
Birch & Stewart Kolasch & Birch, LLP
Cuchlinski, Jr. William A
Marc McDieunel
Nissei Plastic Industrial Co. Ltd.
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