Electricity: motive power systems – Positional servo systems – Program- or pattern-controlled systems
Reexamination Certificate
2001-06-15
2002-11-19
Masih, Karen (Department: 2837)
Electricity: motive power systems
Positional servo systems
Program- or pattern-controlled systems
C318S568100, C318S568200, C318S567000, C700S172000
Reexamination Certificate
active
06483269
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control apparatus for an automatic lathe, which is used for successively choosing a plurality of tools one by one and machining a workpiece into a desirable form according to a machining program.
2. Related Background Art
With reference to
FIGS. 13 and 14
, the configuration of a conventional automatic lathe, e.g., Swiss type automatic lathe, will be explained. In an automatic lathe L, a workpiece
100
is driven to rotate in the direction of arrow A about a center axis of rotation J, while being movable in the directions of arrow B. An area slightly wider than the outside diameter d of the workpiece
100
is defined as a machining area D. Tools move within the machining area D at a predetermined machining speed, thereby machining the workpiece
100
. A plurality of tools
101
,
102
are disposed perpendicular to the center axis of rotation J. According to machining instructions, the tools
101
,
102
move in the directions of arrows E, F, respectively, from their retracted positions indicated by solid lines in FIG.
13
.
The tools
101
,
102
are rapidly fed until they reach the machining area D (until they reach their respective positions indicated by dash-double-dot lines from the positions indicated by solid lines in FIG.
13
), since they are unrelated to the machining of the workpiece
100
until then. The rapid feeding speed has been set for each of the tools
101
,
102
by a machining program beforehand. The starting timing for rapid feeding is set in the machining program as well. Also, as shown in
FIG. 14
, a tool
103
is disposed near the tool
101
. As with the tools
101
,
102
, the tool
103
moves from its retracted position according to a machining instruction. The tool
103
is rapidly fed until it reaches the machining area D.
As shown in
FIG. 14
, the tool
101
is held by a tool holder
104
. Similarly, the tools
102
,
103
are held by tool holders
105
,
106
, respectively. The tool holders
104
,
105
,
106
move together with their corresponding tools
101
,
102
,
103
.
Now, with reference to
FIG. 15
, a control apparatus for an automatic lathe in a conventional technique will be explained. A control apparatus
110
for the automatic lathe L includes a numerical controller NC. The control apparatus
110
comprises an input device
111
for inputting a machining program expressed by a predetermined language, a readout section
112
for reading out the machining program from the input device
111
and digitizing it, and a machining program storage section
114
for storing the digitized machining program into a timing table form in the order of execution.
Here, an example of mode of storage in a timing table form in the machining program storage section
114
will be explained with reference to FIG.
16
. The machining program storage section
114
memorizes that the tool
101
is located at its retracted position P
0
at the point of timing to indicated by time, is placed at its machining operation starting position P
1
at the point of timing t
1
and maintained there until the point of timing T
1
, and is located at a position P
2
within the machining area D at the point of timing T
2
.
An interference determining section
113
is connected to the readout section
112
. The interference determining section
113
determines whether the inputted machining program is appropriate or not, and further determines whether interference occurs or not among individual movable parts of mechanisms in the automatic lathe when the machining proceeds according to the machining program. The result of determination in the interference determining section
113
is fed back to the input device
111
. Here, data concerning the machining program determined by the interference determining section
113
to generate no interference are stored into the machining program storage section
114
.
The machining program storage section
114
sends out the positional data of tools
101
,
102
,
103
stated in the stored machining program, rotational data and movement data of the workpiece
100
, and the like to an instruction generator
115
according to the order of proceeding of program.
The instruction generator
115
converts thus received positional data of tools
101
,
102
,
103
, rotational data and movement data of the workpiece
100
, and the like into control signals of their corresponding motors. While receiving reference timing signals from a reference timing generator
116
which designates actual driving timings, the instruction generator
115
sends out the control signals to a control circuit
117
in synchronization with the proceeding of reference timing signals. An example of the control signals is a driving pulse signal for a predetermined motor.
While receiving feedback signals from a spindle rotating motor
119
, the control circuit
117
functions to correct deviations from the inputted control signals such as driving pulse signals and outputs driving signals to a driving circuit
118
. The spindle rotating motor
119
drives the workpiece
100
to rotate. Here, feedback signals from a spindle moving motor
120
for moving the workpiece
100
in the directions of arrow B, a first tool moving motor
121
for controlling the advancement and retraction of tool
101
, a second tool moving motor
122
for controlling the advancement and retraction of tool
102
, and a third tool moving motor
123
for controlling the advancement and retraction of tool
103
may be fed into the control circuit
117
, the driving circuit
118
, and the like.
The driving circuit
118
controls exciting currents to the spindle rotating motor
119
, spindle moving motor
120
, first tool moving motor
121
, second tool moving motor
122
, and third tool driving motor
123
, and so forth, thereby actually driving the individual motors
119
,
120
,
121
,
122
,
123
.
Now, with reference to
FIGS. 17
to
24
, machining processes by thus configured automatic lathe L will be explained.
First,
FIG. 17
shows a “cutting-off process” in which the tool
102
severs an article
107
from the workpiece
100
. The tool
102
moves at a predetermined machining speed in the direction of arrow F
11
from the machining operation starting position indicated by dash-double-dot lines. The tool
101
is located at the retracted position P
0
(see
FIG. 13
or
14
). Then, as shown in
FIG. 18
, the tool
102
moves in the direction of arrow F
12
, whereby the article
107
is completely cut off. Here, the tool
101
is still located at the retracted position P
0
without moving.
FIG. 19
shows a state where initial positioning for carrying out the subsequent machining process is effected. The tool
102
moves in the direction of arrow F
13
, so as to be positioned at the edge of machining area D. The tool
101
to be involved with the subsequent machining process moves at a rapid feeding speed in the direction of arrow E
11
, so as to be positioned at the edge P
1
of machining area D (see
FIG. 13
or
14
). The workpiece
100
moves in the direction of arrow B
11
, to a position indicated by a solid line. The completion of such initial positioning is governed by the most time-consuming one, whereas those having arrived earlier would wait at their reached positions.
FIG. 20
shows a state immediately before starting a “rough-cutting process” by the tool
101
. The tool
101
moves in the direction of arrow E
12
, thereby reaching a position immediately before starting an actual machining operation. The workpiece
100
moves in the direction of arrow B
12
, thereby reaching a position immediately before starting the actual machining operation.
FIG. 21
shows a state where the “rough-cutting process” by the tool
101
is completed. The workpiece
100
moves in the direction of arrow B
13
thereby reaching its actual machining operation ending position. The tool
101
moves in the direction of arrow E
13
according to the machining program as the time passes.
FIG. 22
shows a state where initial p
Masih Karen
Morgan & Lewis & Bockius, LLP
Star Micronics Co., LTD
LandOfFree
Control apparatus for automatic lathe does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control apparatus for automatic lathe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control apparatus for automatic lathe will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2924178