Tool changing – Tool transfer to or from matrix – Matrix including means to project tool for transfer
Reexamination Certificate
1999-08-09
2001-03-20
Briggs, William (Department: 3722)
Tool changing
Tool transfer to or from matrix
Matrix including means to project tool for transfer
C483S003000, C483S039000, C483S067000
Reexamination Certificate
active
06203479
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, in general, to an automatic tool changing device for NC machine tools and, more particularly, to an automatic tool changing device for machining centers, the device being positioned at a side of the movable table of a machining center and effectively changing tools within the inner diameter circle of a rotary housing, thus shortening the arbor movement stroke and saving tool changing time during a tool changing operation, the device being also effectively protected from the machining part or the spindle stock of such a machining center, thus being almost completely free from any damage caused by chips from the machining part.
2. Description of the Prior Art
As well known to those skilled in the art, machining centers are NC (numerical control) machine tools for shaping, cutting, milling, turning, boring, drilling, grinding, or polishing of solid parts, especially metals, under computer numerical control by making use of several axes and a variety of tools and operations. The construction of a typical machining center is shown in FIG.
7
.
As shown in the drawing, the typical machining center comprises a bed
11
, with a table
111
being carried on the bed
11
to be horizontally movable along an X-axis of the bed
11
. A column
12
is positioned in back of the bed
11
to be vertically movable along a Y-axis of the bed
11
. A spindle stock
13
is positioned in front of the bed
11
to be horizontally movable along a Z-axis of the bed
11
, with a tool carrying arbor
100
being fixed to the stock
13
. An automatic tool changing device (ATC)
9
is set on a side of the column
12
and is used for automatically changing tools for the spindle stock
13
.
The construction of such a typical ATC is shown in
FIGS. 8
a
and
8
b
in detail.
As shown in the drawings, the typical ATC
9
comprises a rotary tool carrier
91
. The rotary tool carrier
91
, set on a side of the column
12
, is designed for being rotatable around its center shaft
911
. An arbor position changer
92
is positioned under the rotary tool carrier
91
and is used for changing the position of a tool carrying arbor
100
from its horizontal position to its vertical position. A tool changer
93
is positioned at a side of the arbor position changer
92
and is used for moving the arbor
100
to the spindle stock
13
prior to changing an existing tool of the stock
13
with a new tool or the tool of the above arbor
100
.
When it is necessary to change an existing tool of the stock
13
with a new tool using the above ATC
9
, the tool carrier
91
is rotated around its center shaft
911
so as to allow the ATC to select a desired arbor
100
from a plurality of arbors
100
provided on the carrier
91
. Of course, the arbors
100
individually carry a tool, so that the number of arbors
100
is determined by the number of tools for the machining center. The selected arbor
100
is, thereafter, horizontally laid on the center under the tool carrier
91
prior to being positioned vertically by the arbor position changer
92
. The ATC
9
moves the vertically positioned arbor
100
to the spindle stock
13
by the tool changer
93
prior to changing the existing tool with the tool of the selected arbor
100
.
However, such an ATC
9
is problematic in that it performs an automatic tool changing operation at the outer diameter circle of the rotary tool carrier
91
, thus rendering the arbors
100
to move in a long stroke during a tool changing operation. This results in consumption of time during such a tool changing operation.
Another problem experienced in the typical ATC
9
resides in that it is positioned above the machining part of the machining center at a side of the column
12
. The ATC
9
may be thus easily damaged or broken by the chips from the machining part.
In the prior art, the ATC
9
, which is set on the column
12
to project outwardly, is covered and protected by an ATC casing. However, in order to effectively protect the ATC
9
, the ATC cover has to be designed for having a large volume and this increases the manufacturing cost of such machining centers.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an ATC for machining centers, which is positioned at a side of the movable table of a machining center and effectively changes tools within the inner diameter circle of a rotary housing, thus shortening the arbor movement stroke and conserving tool changing time during a tool changing operation.
Another object of the present invention is to provide an ATC for machining centers, which is also effectively protected from the machining part or the spindle stock of a machining center, thus being almost completely free from any damage caused by chips from the machining part.
A further object of the present invention is to provide an ATC for machining centers, which is positioned at a side of the movable table in place of the column different from a typical ATC, thus remarkably reducing the volume of the ATC protection cover and saving the manufacturing cost of such machining centers.
In order to accomplish the above object, the present invention provides an automatic tool changing device for machining tools, the machining tools individually comprising a bed movably carrying a table to allow the table to be movable along an X-axis of the bed, a column positioned at a side of the bed to be movable along a Y-axis of the bed, and a spindle stock positioned in front of the column to be movable along a Z-axis of the bed with a tool carrying arbor being held to the spindle stock, comprising: arbor rotation guide means provided on the bed at a position around the table and adapted for guiding a rotating action of a plurality of tool carrying arbors; arbor position changing means positioned above the arbor rotation guide means and adapted for selectively changing a position of a selected one of the arbors from its horizontal position to its vertical position; arbor rotation means installed inside the arbor rotation guide means and adapted for rotating the arbors; and tool changing means positioned between the arbor rotation means and the spindle stock and adapted for changing an existing arbor of the spindle stock with the selected arbor.
REFERENCES:
patent: 4119213 (1978-10-01), Sato et al.
patent: 4335500 (1982-06-01), Munekata et al.
patent: 5322494 (1994-06-01), Holtey et al.
patent: 5649887 (1997-07-01), Taki et al.
patent: 165950 (1983-10-01), None
patent: 123240 (1985-07-01), None
patent: 48438 (1987-03-01), None
patent: 5-33242 (1993-08-01), None
Gengo Ohira
Kim Chang Yong
Kim Ki Tai
Briggs William
Hwacheon Machine Tool Co., Ltd.
Jacobson Price Holman & Stern PLLC
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