Feed control apparatus for a machine tool carriage
First Claim
1. A feed control apparatus for a carriage which is drivingly connected to a servomotor through a feed screw for slide movement on a guide base of a machine tool, comprising:
- a numerical controller responsive to numerical control information for outputting feed pulses sselectively at a first frequency for rapid feed, a second frequency for slow-down feed and a third frequency for machining feed;
servomotor control means connected to said numerical controller and said servomotor for controlling rotation of said servomotor in response to said feed pulses output from said numerical controller;
detection means for detecting whether or not said carriage has reached a velocity checking point defined within a slow-down feed range of said carriage, so as to emit a velocity checking signal when the reaching of said carriage to said velocity checking point is detected;
abnormality confirmation circuit means capable of confirming whether or not the actual feed rate of said carriage has been reduced below a reference feed rate, which is lower by a predetermined value than a rapid feed rate, and responsive to said velocity checking signal for outputting an abnormality signal when it is confirmed that the actual feed rate of said carriage still exceeds said reference feed rate; and
emergency stop circuit means connected to said servomotor control means and said abnormality confirmation circuit means and responsive to said abnormality signal for causing said servomotor control means to immediately discontinue rotation of said servomotor.
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Accused Products
Abstract
A feed control apparatus wherein a servomotor control device responsive to feed pulses distributed from a numerical controller controls a d.c. servomotor to advance a grinding wheel carriage of a grinding machine through the rotation of a feed screw successsively at a speed-up feed rate, a rapid feed rate, a slow-down feed rate and a grinding feed rate. A detection device is provided, which outputs a velocity checking signal to an abnormality confirmation device when the carriage reaches a velocity checking point defined within a slow-down feed range. When confirming that the feed rate of the carriage has exceeded a reference feed rate lower than the rapid feed rate, the abnormality confirmation device applies a stop signal to an emergency stop control circuit in response to the velocity checking signal, so that the rotation of the servomotor is immediately discontinued.
17 Citations
7 Claims
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1. A feed control apparatus for a carriage which is drivingly connected to a servomotor through a feed screw for slide movement on a guide base of a machine tool, comprising:
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a numerical controller responsive to numerical control information for outputting feed pulses sselectively at a first frequency for rapid feed, a second frequency for slow-down feed and a third frequency for machining feed; servomotor control means connected to said numerical controller and said servomotor for controlling rotation of said servomotor in response to said feed pulses output from said numerical controller; detection means for detecting whether or not said carriage has reached a velocity checking point defined within a slow-down feed range of said carriage, so as to emit a velocity checking signal when the reaching of said carriage to said velocity checking point is detected; abnormality confirmation circuit means capable of confirming whether or not the actual feed rate of said carriage has been reduced below a reference feed rate, which is lower by a predetermined value than a rapid feed rate, and responsive to said velocity checking signal for outputting an abnormality signal when it is confirmed that the actual feed rate of said carriage still exceeds said reference feed rate; and emergency stop circuit means connected to said servomotor control means and said abnormality confirmation circuit means and responsive to said abnormality signal for causing said servomotor control means to immediately discontinue rotation of said servomotor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification