Metal working – Plural diverse manufacturing apparatus including means for... – Binding or covering and cutting
Reexamination Certificate
2002-04-11
2003-11-18
Wellington, A. L. (Department: 3652)
Metal working
Plural diverse manufacturing apparatus including means for...
Binding or covering and cutting
C409S159000, C414S744300, C198S346100
Reexamination Certificate
active
06647605
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a machine tool for machining a workpiece by moving a tool and the workpiece relative to each other and to a pallet changer thereof, and particularly to a machine tool such as a machining center having a pallet changer attached thereto for changing pallets having a workpiece mounted thereon between a table and a pallet stocker, i.e. a pallet loading station and to a pallet changer thereof.
BACKGROUND ART
Generally, a machine tool such as a machining center is provided with a pallet changer, by which a pallet having a machined workpiece mounted thereon and placed on the table of the machine tool is exchanged with a pallet having a set-up workpiece mounted thereon and placed on a pallet loading station. Such a pallet changer is disclosed, for example, in Japanese Unexamined Utility Model Publication No. 2-53335. This pallet changer comprises pallet change arms which are adapted to be able to swivel about a vertical axis and to move up and down (in a vertical direction).
The pallet changer for a machine tool disclosed in Japanese Unexamined Utility Model Publication No. 2-53335 is configured of a frame structure including a beam arranged above the pallet change arms, an arm shaft fixed to the pallet change arms and supported vertically movably and swingably by the beam of the frame structure, and actuators arranged on the beam for vertically moving the arm shaft and swiveling it. In exchanging the pallets, the pallets are released from each of the table and the pallet loading station, and the pallet change arms are then moved up through the arm shaft by a first actuator, thereby to lift up the pallets on the table and on the pallet loading station to an upper pallet changing position. Next, the pallet change arms are swiveled through the arm shaft by a second actuator, so that the pallet on the side of the table (i.e. the machining position) is replaced with the pallet on the side of the pallet loading station (i.e. the standby position). After that, the pallet change arms are moved down to a lower pallet mounting position through the arm shaft by the first actuator, and the pallets are placed and fixed on the table and the pallet loading station, respectively.
In the pallet changer for the machine tool disclosed in Japanese Unexamined Utility Model Publication No. 2-53335, the pallet change arms on the sides of both the table and the pallet loading station can be moved down only to the same vertical position along with each other. In other words, the vertical position of the pallet on the side of the pallet loading station is set to the same vertical position as the pallet mounting position on the table.
While the workpiece on the pallet is being machined on the side of the table, the set-up process is conducted, on the side of the pallet loading station, for mounting on a pallet a next workpiece to be machined and removing the machined workpiece from the pallet, etc. In the case of the pallet changer disclosed in Japanese Unexamined Utility Model Publication No. 2-53335, however, the pallet change arms on the sides of the table and the pallet loading station can be moved down only to the same vertical position. Especially in a large-size machine tool such a machining center, this results in the very high vertical position for the pallet loading station, and therefore a stool or the like is required for the set-up job, thereby posing the problem of a deteriorated working environment and safety.
DISCLOSURE OF THE INVENTION
Accordingly, an object of the present invention is to provide a machine tool, and a pallet changer therefor, in which the vertical position of the working surface for the pallet loading station can be set to a lower level than the upper surface of the machine tool table in carrying out the set-up job for changing the pallets between the pallet loading station for set-up job and the table.
Another object of the invention is to provide a machine tool, and a pallet changer therefor, in which the vertical position of the pallet change arm on the side of the pallet loading station can be freely set independently of the vertical position of the upper surface of the table.
According to a first aspect of the present invention, there is provided a machine tool for machining a workpiece by moving a tool and the workpiece in relation to each other, which includes a spindle for mounting the tool thereon, a table for a pallet having the workpiece mounted thereon to be placed on the table, a pallet loading station for conducting the set-up job thereon including the mounting/demounting of the workpiece on/from the pallet, and a pallet changer including a pair of pallet change arms, each pallet change arm having a pallet holder for holding selected one of a pallet on the table and a pallet on the pallet loading station, the pair of the pallet change arms being swiveled about a vertical axis thereby to exchange the pallets between the table and the pallet loading station, the pair of the pallet change arms arranged to be able move independently of each other in the vertical direction.
According to a second aspect of the present invention, there is provided a machine tool for machining a workpiece by moving a tool and the workpiece in relation to each other, which includes a spindle for mounting the tool thereon, a table for a pallet having the workpiece mounted thereon to be placed on the table, a pallet loading station for conducting the set-up job including the mounting/demounting of the workpiece on/from the pallet, and a pallet changer including a support body interposed between the table and the pallet loading station and able to swivel about a vertical axis, and a pair of pallet change arms mounted on the support body and extending horizontally in opposite directions from the support body, the support body being swiveled thereby to move one of the pallet change arms from the side of the table to the side of the pallet loading station and the other pallet change arm from the side of the pallet load station to the side of the table, the pair of the pallet change arms being able to move independently of each other, in the vertical direction, on the support body.
According to a third aspect of the present invention, there is provided a machine tool for machining a workpiece by moving a tool and the workpiece in relation to each other, which includes a spindle for mounting the tool mounted thereon, a table for a pallet having the workpiece mounted thereon to be placed on the table, a pallet loading station for conducting the set-up job thereon including the mounting/demounting of the workpiece on/from the pallet, a base disposed between the table and the pallet loading station, a support body able to swivel in relation to the base about a vertical axis, swiveling means disposed on the base for swiveling the support body, a pair of pallet change arms, each pallet change arm including a pallet holder for holding a pallet on the table or a pallet on the pallet loading station, the pair of the pallet change arms arranged to swivel integrally with the support body by the swiveling means and to be able to move independently of each other in the vertical direction on the support body and first vertical driving means disposed on the support body for vertically moving one of the pair of the pallet change arms, second vertical driving means disposed on the support body in series with the first vertical driving means for vertically moving the pair of the pallet changer arms in cooperation with the first vertical driving means, and a stopper for restricting the movement of one of the pair of the pallet change arms on the side of the table, when the pair of the pallet change arms are moved downward by the second vertical driving means.
According to a fourth aspect of the present invention, there is provided a machine tool for machining a workpiece by moving a tool and the workpiece in relation to each other, which includes a spindle for mounting the tool mounted thereon, a table for a pallet having the workpiece mounted thereon to be placed
Hiramoto Kazuyuki
Hoshi Takashi
Tada Keigo
Cadugan Erica E
Makino Milling Machine Co., Ltd.
Paul & Paul
Wellington A. L.
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