Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
2002-09-25
2004-06-22
Picard, Leo (Department: 2125)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S255000
Reexamination Certificate
active
06754555
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an interference preventing apparatus and, more specifically, to an apparatus for preventing a movable member and a structural member of an NC machine tool from interfering with each other in any of plural interfering relationships.
2. Description of Related Art
An interference preventing apparatus as shown in
FIG. 8
is conventionally known as the interference preventing apparatus of the aforesaid type. As shown in
FIG. 8
, the interference preventing apparatus
50
is accommodated in a numerical controller
60
of an NC machine tool, and includes an interference area defining section
51
, an interference area data storage section
52
, an interference checking section
53
and an alarm section
54
.
In the following description, it is assumed that an NC lathe is employed which includes a tool post for holding a tool, a headstock for rotatably supporting a spindle, and a tailstock disposed in opposed relation to the headstock for rotatably supporting a tailstock spindle, and the interference preventing apparatus
50
is adapted to prevent interference between the tool and a spindle portion (including the spindle and a chuck attached to the spindle) and interference between the tool and a tailstock portion (including the tailstock and the tailstock spindle) in the NC lathe.
The numerical controller
60
further includes an NC program storage section
61
, a program analyzing section
62
, a tool offset amount storage section
63
and a drive controlling section
64
. The interference area defining section
51
, the interference checking section
53
, the alarm section
54
and the drive controlling section
64
are connected to an input/output device
71
including an operating panel and a CRT. The drive controlling section
64
is connected to driving means
72
including a servo motor and a spindle motor for moving the tool post.
The NC program storage section
61
stores therein preliminarily generated NC programs. The tool offset amount storage section
63
stores therein a tool offset amount for each tool held by the tool post.
The program analyzing section
62
sequentially analyzes the NC programs stored in the NC program storage section
61
, extracts a command related to a movement position of the tool post, and outputs the extracted command to the drive controlling section
64
.
The drive controlling section
64
controls the movement of the tool post and the rotation of the spindle. For the movement of the tool post, for example, the drive controlling section
64
generates target movement position data for the tool post on the basis of the command signal outputted from the program analyzing section
62
and the tool offset amount of the tool stored in the tool offset amount storage section
63
, and then properly processes the target movement position data for generation of a control signal, which is in turn outputted to the driving means
72
for controlling the driving means
72
.
Where a pulse handle provided on the operation panel of the input/output device
71
is operated for manual operation, for example, a pulse signal is outputted to the drive controlling section
64
from the pulse handle. Then, the drive controlling section
64
generates target movement position data on the basis of the number of pulses of the received pulse signal, and properly processes the target movement position data for generation of a control signal, which is in turn outputted to the driving means
72
for controlling the driving means
72
.
The tool post target movement position data generated by the drive controlling section
64
is outputted to the interference checking section
53
.
The interference area defining section
51
defines interference areas where the tool is likely to interfere with the spindle portion and the tailstock portion within a area where the tool held by the tool post is movable. For example, the interference areas are interactively defined by means of the input/output device
71
, and data indicative of the interference areas is stored in the interference area data storage section
52
. The interference areas are represented by position coordinate data which defines the contours of the spindle portion and the tailstock portion in a machine coordinate system, and areas within the contours are regarded as the interference areas.
The interference checking section
53
checks for a possibility of the interference between the tool and the spindle portion and a possibility of the interference between the tool and the tailstock portion upon reception of a process implementation signal from the program analyzing section
62
in an automatic operation or upon reception of a process implementation signal from the input/output device
71
in the manual operation.
More specifically, the interference area data is read out of the interference area data storage section
52
, and a tool offset amount of a tool indexed in a machining position is read out of the tool offset amount storage section
63
. Then, movement target positions of an edge of the tool in the machine coordinate system are sequentially calculated on the basis of the tool offset amount thus read out and the tool post target movement position data outputted from the drive controlling section
64
. The movement target position data thus calculated is compared with the interference area data for determining whether or not the movement target positions are located within the interference areas. If any of the movement target positions is located within the interference areas, the possibility of the interference is confirmed.
Where the possibility of the interference between the tool and the spindle portion or the tailstock portion is confirmed, the interference checking section
53
outputs a drive stopping signal (interference confirming signal) to the drive controlling section
64
, and outputs an alarm display signal (interference confirming signal) to the alarm section
54
.
The alarm section
54
displays an alarm on the CRT of the input/output device
71
upon reception of the alarm display signal from the interference checking section
53
.
In the interference preventing apparatus
50
having the aforesaid construction, the interference checking section
53
determines whether or not the tool has a possibility to interfere with the spindle portion and the tailstock portion in the automatic operation or in the manual operation. If the possibility of the interference is confirmed, the drive stopping signal is outputted to the drive controlling section
64
from the interference checking section
53
for stopping the movement of the tool post. Thus, the interference between the tool and the spindle portion and the interference between the tool and the tailstock portion are prevented. Further, the alarm display signal is outputted to the alarm section
54
from the interference checking section
53
, and the alarm is displayed on the CRT.
However, the conventional interference preventing apparatus
50
described above is given an option to perform or not to perform the interference checking operation for all of the interference areas at a time. In other words, the interference preventing apparatus
50
is not given an option to perform or not to perform the interference checking operation for each of the interference areas and, therefore, suffers from the following drawbacks.
After exchange of the tool attached to the tool post, for example, the tool offset amount should be reset for a tool newly attached to the tool post. A tool offset amount setting operation is performed by employing a preseter or by actually machining a workpiece. In either case, the tool post should be moved toward the spindle for the setting of the tool offset amount.
If the interference checking section
53
is permitted to perform the interference checking operation when the tool offset amount setting operation is performed, the interference checking section
53
calculates the target movement positions of the edge of the tool on the basis o
Frank Elliot L
Mori Seiki Co. Ltd.
Picard Leo
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