Claims
- 1. In a grinding assembly for grinding off the molding fin from a rough casting on which the fin extends in a plane substantially at right angles to the surface of the casting, the combination comprising a grinding wheel having a rotary drive for rotating it at a reference speed, means including a carriage for mounting the grinding wheel for bodily relative movement in feed and return directions, means including a jig for mounting the casting in front of the grinding wheel, feed driving means for driving the carriage in the feed direction at a reference feed rate so that the grinding wheel grinds away the fin as it proceeds toward the surface of the casting, means for constantly measuring the load imposed upon the rotary drive and for producing an output signal which is a function of the load and which sharply increases in magnitude as the surface of the casting is encountered at the base of the fin, feed shut-off means for shutting off the feeding movement of the carriage, means responsive to the magnitude of the output signal for triggering the feed shut-off means to the shut-off condition upon sudden increase of the output signal indicating that the engaged portion of the fin has been removed and that the surface of the casting is being encountered, the shut-off means inhibiting the feeding movement of the carriage in the feed direction for a time greater than the response time of the feed driving means and means for imparting relative traversing movement to the casting.
- 2. In a grinding assembly for grinding off the molding fin from a circular casting on which the fin extends in a plane substantially at right angles to the axis of the casting, the combination comprising a grinding wheel having a rotary drive for rotating it at a reference speed, means including a carriage for mounting the grinding wheel for bodily relative movement in feed and return directions, means for chucking the casting in front of the grinding wheel for rotation about axis, feed driving means for driving the carriage in the feed direction at a reference feed rate so that the grinding wheel grinds away the fin as it proceeds toward the surface of the casting, means for constantly measuring the load imposed upon the rotary drive and for producing an output signal which is a function of the load and which sharply increases in magnitude as the surface of the casting is encountered at the base of the fin, feed shut-off means for shutting off the feeding movement of the carriage, means responsive to the magnitude of the output signal for triggering the feed shut-off means to the shut-off condition upon sudden increase of the output signal indicating that the surface of the casting is being encountered, the shut-off means inhibiting the feeding movement of the carriage in the feed direction for a time greater than the response time of the feed driving means and means for rotating the casting about its axis to provide circular traversing movement between the casting and the wheel for grinding off the fin about the entire periphery of the casting.
- 3. In a grinding assembly for grinding off the molding fin from a rough casting in which the fin extends in a plane substantially at right angles to the surface of the casting, the combination comprising a grinding wheel having a rotary drive for rotating it at a reference speed, means including a carriage for mounting the grinding wheel for bodily relative movement in feed and return directions, means including a jig for mounting the casting in front of the grinding wheel, feed driving means for driving the carriage in the feed direction at a reference feed rate so that the grinding wheel grinds away the fin as it proceeds toward the surface of the casting, means for constantly measuring the load imposed upon the rotary drive and for producing an output signal which is a function of the load and which sharply increases in magnitude as the surface of the casting is encountered at the base of the fin, means for shutting off the feeding movement of the carriage, means responsive to the magnitude of the output signal for triggering the shut-off means upon sudden increase of the output signal indicating that the engaged portion of the fin has been removed and that the surface of the casting is being encountered, means for thereafter retracting the carriage so that the wheel is retracted outward from the surface contour of the casting to complete a single feed and retract cycle, means for continuously repeating the cycle, and means for imparting relative traversing movement to the casting as the cycle is repeated.
- 4. In a grinding assembly for grinding off the molding fin from a rough casting in which the fin extends in a plane substantially at right angles to the surface of the casting, the combination comprising a grinding wheel having a rotary drive for rotating it at a reference speed, means including a carriage for mounting the grinding wheel for bodily relative movement in feed and retract directions, means including a jig for mounting the casting in front of the grinding wheel, feed driving means for driving the carriage in the feed direction from a reference position and at a reference feed rate so that the grinding wheel grinds away the fin as it proceeds toward the surface of the casting, means for constantly measuring the load imposed upon the rotary drive and for producing an output signal which is a function of the load and which sharply increases in magnitude as the surface of the casting is encountered at the base of the fin, means for shutting off the feeding movement of the carriage and for causing the carriage to retract through a predetermined distance to a new reference position to complete a single feed and retract cycle, means responsive to the magnitude of the output signal for triggering the feed shut-off means upon sudden increase of the output signal indicating that the engaged portion of the fin has been removed and that the surface of the casting is being encountered, means for imparting relative transversing movement to the casting, and means responsive to the carriage reaching its new reference position for automatically initiating an ensuing cycle of feeding movement, the predetermined distance of retraction being substantially less than the maximum protruding distance of the fin outward from the surface contour of the casting in the carriage retract direction.
- 5. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which the output signal is proportional to the load on the rotary drive.
- 6. The combinaton as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which a differentiating device is provided for responding to the load measuring means to produce an output signal which is a first derivative function of the load.
- 7. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which means are provided for responding to the load measuring means to produce an output signal which is an exponential function of the load and in which the exponent is greater than one.
- 8. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which the rotary drive for the wheel is in the form of an electric motor and in which the means for constantly measuring the load imposed thereon is in the form of motor current measuring means.
- 9. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which the rotary drive for the wheel is in the form of an electric motor and in which the means for constantly measuring the load imposed thereon is in the form of torque measuring means for measuring the reaction torque imposed upon the wheel by the casting.
- 10. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which an adjustable source of reference signal is provided and in which the means responsive to the magnitude of the output signal is in the form of a comparator for comparing the reference signal to the output signal for triggering the feed shut-off means when the output signal bears a predetermined relation to the reference signal.
- 11. The combination as claimed in claim 3 or claim 4 in which the rate of retracting movement of the carriage greatly exceeds the rate of feeding movement.
- 12. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which the plane of the fin substantially intersects the center of the wheel.
- 13. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which the plane of the fin is parallel to the wheel axis.
- 14. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which means are provided for maintaining the speed of traversing movement of the casting substantially constant.
- 15. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which the means for imparting relative traversing movement to the casting is in the form of indexing means so that the casting is traversed in stepped increments.
- 16. The combination as claimed in claim 1 or claim 2 or claim 3 or claim 4 in which the means for imparting relative traversing movement to the casting is in the form of indexing means with means for synchronizing the indexing movements with the feed movements of the carriage.
- 17. The combination as claimed in claim 1 or claim 3 or claim 4 in which the casting is mounted for rotational movement about an axis which is substantially perpendicular to the plane of the fin.
- 18. The combination as claimed in claim 1 or claim 3 or claim 4 in which the means for imparting relative traversing movement to the casting causes the casting to be translated in front of the grinding wheel in the plane of the fin.
- 19. In a grinding assembly for grinding off the molding fin from a rough casting in which the fin extends in a plane substantially at right angles to the surface of the casting, the combination comprising a grinding wheel having a rotary drive for rotating it at a reference speed, means including a carriage for mounting the grinding wheel for bodily relative movement in feed and return directions, means including a jig for mounting the casting in front of the grinding wheel, feed driving means for driving the carriage in the feed direction at a reference feed rate so that the grinding wheel grinds away the fin as it proceeds toward the surface of the casting, means for detecting the contour of the workpiece by engagement of the grinding wheel with the workpiece as the fin is removed and generating an output signal indicating the actual contact area between the grinding wheel and the workpiece so that the output signal sharply increases in magnitude as the surface of the casting is encountered at the base of the fin, means for shutting off the feeding movement of the carriage, means responsive to the magnitude of the output signal for triggering the shut-off means upon adding increase of the output signal indicating that the engaged portion of the fin has been removed and that the surface of the casting is being encountered, means for thereafter retracting the carriage so that the wheel is retracted outward from the surface contour of the casting to complete a single feed and retract cycle, means for continuously repeating the cycle, and means for imparting relative traversing movement to the casting as the cycle is repeated.
- 20. The combination as claimed in claim 19, in which the means for detecting the contour of the workpiece has a differentiating device and wherein the output signal indicates the time rate of change of the actual contact area between the grinding wheel and the workpiece.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2930309 |
Jul 1979 |
DEX |
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RELATED APPLICATIONS
This application is a continuation in part of Feltd, Wolfgang and Bautz, Walter application Ser. No. 6/172,090 filed July 25, 1980 now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (1)
Number |
Date |
Country |
782432 |
Sep 1957 |
GBX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
172090 |
Jul 1980 |
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