US3798845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Grinding wheel truing control apparatus
Assignee: Pratt and Whitney Co Inc
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Filing: 1971-09-24
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Granted: 1974-03-26
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Expires: 1991-09-24
Abstract
Abstract Apparatus and method for automatically increasing and determining the frequency of truing a grinding wheel in a grinding machine having means for compensating for the reduction in radius of the grinding wheel and to advance the grinding wheel to maintain the retracted position of the cutting face of the grinding wheel at a predetermined substantially constant distance from the work support means. Truing control means are provided for counting the workpieces being ground and initiating the truing means, and sensing means responsive to the amount of compensating movement to periodically produce and send an additional count to the counting means whereby the predetermined number of counts for which the counting means has been preset to initiate a truing cycle is reached prior to grinding the preset number of workpieces. Thus the number of workpieces ground by the wheel is periodically decreased in direct proportion to the reduction in the radius of the grinding wheel.
Inventors
- 👤 T Stevens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:28
CPC Classifications
B; B24; B24B; B24B49/00; B24B49/18
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
487 words
In a grinding machine having a base, a movable support on the base, a grinding wheel rotatably supported on the movable support and having a cutting face rotatable about and at a predetermined radius from an axis of rotation, drive means for rotating the grinding wheel on the movable support, work support means for supporting a workpiece opposite the cutting face of the grinding wheel, feed means for moving the movable support relative to the base and the cutting face of the grinding wheel toward the work support means to grind the workpiece to finish size and thereafter away from the work support means to a retracted position, truing means for dressing the cutting face on the grinding wheel whereby the radius and circumference of the grinding wheel is reduced a predetermined amount, compensating means for advancing the movable support and the grinding wheel relative to the base and toward the work support means the predetermined amount the radius of the grinding wheel is reduced by the truing means whereby an initial position of the cutting face of the wheel is reestablished at a substantially constant distance from the work support means and the finish size of the workpiece, wherein the improvement comprises: truing control means, responsive to changes in the retracted position and compensating movement of the movable support relative to the base by the compensating means, for periodically actuating the truing means at progressively increasing frequency in accordance with the reduction in the radius and circumference of the grinding wheel and determining the number of workpieces to be ground thereby between dressings of the cutting face by the truing means, said truing control means comprises: counting means, operatively connected to the truing means and preset for counting a desired number of impulses which represents an initial number of workpieces to be ground by the cutting surface of the wheel at the beginning of a grinding operation when the radius and circumference of the wheel is largest and for actuating the truing means for dressing the grinding wheel when the preset number of impulses are received; signal means, operatively connected to the counting means, for sending an impulse thereto each time a workpiece has been ground by the grinding wheel; sensing means, actuated each time the movable support is returned to the retracted position for determining the amount of compensating movement of the movable support relative to the base and reducting in the radius of the wheels; switch means, operatively connected to and periodically actuated by the sensing means at progressively increasing frequency as the compensating movement increases in response to reductions in the radius of the wheel, for periodically sending an additional impulse, not representing a ground workpiece, to the counting means; whereby the counting means is periodically advanced and reduces the number of workpieces ground by the grinding wheel in direct proportion to the reduction in the radius and circumference of the grinding wheel.
Claim 2
Dependent Claim
487 words
In a grinding machine having a base, a movable support on the base, a grinding wheel rotatably supported on the movable support and having a cutting face rotatable about and at a predetermined radius from an axis of rotation, drive means for rotating the grinding wheel on the movable support, work support means for supporting a workpiece opposite the cutting face of the grinding wheel, feed means for moving the movable support relative to the base and the cutting face of the grinding wheel toward the work support means to grind the workpiece to finish size and thereafter away from the work support means to a retracted position, truing means for dressing the cutting face on the grinding wheel whereby the radius and circumference of the grinding wheel is reduced a predetermined amount, compensating means for advancing the movable support and the grinding wheel relative to the base and toward the work support means the predetermined amount the radius of the grinding wheel is reduced by the truing means whereby an initial position of the cutting face of the wheel is reestablished at a substantially constant distance from the work support means and the finish size of the workpiece, wherein the improvement comprises: truing control means, responsive to changes in the retracted position and compensating movement of the movable support relative to the base by the compensating means, for periodically actuating the truing means at progressively increasing frequency in accordance with the reduction in the radius and circumference of the grinding wheel and determining the number of workpieces to be ground thereby between dressings of the cutting face by the truing means, said truing control means comprises: counting means, operatively connected to the truing means and preset for counting a desired number of impulses which represents an initial number of workpieces to be ground by the cutting surface of the wheel at the beginning of a grinding operation when the radius and circumference of the wheel is largest and for actuating the truing means for dressing the grinding wheel when the preset number of impulses are received; signal means, operatively connected to the counting means, for sending an impulse thereto each time a workpiece has been ground by the grinding wheel; sensing means, actuated each time the movable support is returned to the retracted position for determining the amount of compensating movement of the movable support relative to the base and reducting in the radius of the wheels; switch means, operatively connected to and periodically actuated by the sensing means at progressively increasing frequency as the compensating movement increases in response to reductions in the radius of the wheel, for periodically sending an additional impulse, not representing a ground workpiece, to the counting means; whereby the counting means is periodically advanced and reduces the number of workpieces ground by the grinding wheel in direct proportion to the reduction in the radius and circumference of the grinding wheel.
Claim 3
Dependent Claim
377 words
In a grinding machine according to claim 1 wherein the sensing means comprises: a cYlinder mounted on the base adjacent the movable support; a rack piston with rack teeth thereon slidably mounted in the cylinder and having a stroke of movement relative to the cylinder of a length at least equal to a usable radial portion between a maximum radius of the grinding wheel and a minimum radius at which the grinding wheel is to be replaced; a piston rod extending from the rack piston and out through one end of the cylinder and movable into engagement with the movable support in the retracted position; a gear rotatably mounted on the cylinder and having gear teeth meshing with the rack teeth on the rack piston and a pitch circle of a circumference equal to the length of the usable radial portion of the grinding wheel; a one way over running clutch operatively connected to and driven by the gear; a cam operatively connected to and rotatably driven in one direction by the over running clutch relative to the switch means; actuating means operatively connected to the cylinder for moving the rack piston relative to the cylinder and the piston rod into and out of engagement with the movable support in the retracted position; whereby when the grinding wheel is at the minimum radius and the distance between the movable support and the piston rod is equal to the length of the usual radial portion a single stroke of the piston rotates the gear and the cam one complete revolution which actuates the switch means sending the additional impulse to the counting means, and when the radius of the wheel is between the maximum radius and the minimum radius and the distance between the movable support and the piston rod is less than the length of the usable radial portion a single stroke of the rack piston rotates the cam a part of a revolution each time the movable support is moved to the retracted position and the length of the stroke determines the number of retractions of the movable support, the number of strokes of the piston, and the number of parts of a revolution required to rotate the cam one revolution to actuate the switch means.
Claim 4
Dependent Claim
40 words
In a grinding machine according to claim 2 wherein the signal means comprises: a limit switch actuated each time a movable support is moved to the retracted position sending the impulse to the counting means and energizing the actuating means.
Claim 5
Dependent Claim
37 words
In a grinding machine according to claim 2 wherein the actuating means comprises: a solenoid operated fluid directional control valve for directing fluid under pressure to and from opposite ends of the cylinder and the rack piston.
Claim 6
Dependent Claim
47 words
In a grinding machine according to claim 4 wherein the actuating means further comprises: a time delay switch connected to and energized by the limit switch and operatively connected to first energize and then de-energize the solenoid operated valve after a predetermined interval of time has elasped.
Claim 7
Dependent Claim
187 words
In a grinding machine for sequentially grinding each of a plurality of workpieces and having a base, a movable support on the base, a circular grinding wheel rotatably supported on the movable support and having a cutting face, drive means for rotating the grinding wheel, work support means for supporting each of the workpieces in turn, feed means for moving the movable support relative to the base and the cutting face of the grinding wheel toward the work support means to grind a workpiece held by said work support means; truing means operable through a wheel dressing cycle to dress the cutting face on the grinding wheel with a resulting reduction in the radius and circumference of the grinding wheel, wherein the improvement comprises: truing control means for effecting operation of said truing means through a wheel dressing cycle in response to the grinding of a predetermined number of workpieces by said grinding machine and for reducing the predetermined number of workpieces ground by said grinding machine between successive wheel dressing cycles as a function of A reduction in the radius and circumference of the grinding wheel.
Claim 8
Dependent Claim
187 words
In a grinding machine for sequentially grinding each of a plurality of workpieces and having a base, a movable support on the base, a circular grinding wheel rotatably supported on the movable support and having a cutting face, drive means for rotating the grinding wheel, work support means for supporting each of the workpieces in turn, feed means for moving the movable support relative to the base and the cutting face of the grinding wheel toward the work support means to grind a workpiece held by said work support means; truing means operable through a wheel dressing cycle to dress the cutting face on the grinding wheel with a resulting reduction in the radius and circumference of the grinding wheel, wherein the improvement comprises: truing control means for effecting operation of said truing means through a wheel dressing cycle in response to the grinding of a predetermined number of workpieces by said grinding machine and for reducing the predetermined number of workpieces ground by said grinding machine between successive wheel dressing cycles as a function of A reduction in the radius and circumference of the grinding wheel.
Claim 9
Dependent Claim
403 words
In a grinding machine as set forth in claim 6 wherein said truing control means includes detector means for detecting the grinding of successive workpieces and providing an output signal in response to the grinding of each of the workpieces, signal generator means for providing an output signal upon operation of said grinding machine to grind a number of workpieces which varies as a function of variations in the radius and circumference of the grinding wheel, and counter means for receiving output signals from said detector means and signal generator means and for effecting the initiation of a wheel dressing cycle in response to the receiving of a predetermined number of output signals. 8 In a grinding machine having a base, a movable support on the base, a grinding wheel rotatably supported on the movable support and having a cutting face rotatable about and at a predetermined radius from an axis of rotation, drive means for rotating the grinding wheel on the movable support, work support means for supporting a workpiece opposite the cutting face of the grinding wheel, feed means for moving the movable support and grinding wheel toward the work support means to a finish grind position at which the workpiece is ground to a finish size and thereafter away from the work support means to a retracted position, truing means for dressing the cutting face on the movable support whereby the radius and circumference of the grinding wheel is reduced a predetermined amount with a resulting change in the finish grind position of the grinding wheel during the subsequent grinding of workpieces, wherein the improvement comprises: truing control means for effecting periodic operation of said truing means with a frequency which varies as a function of the number of workpieces ground and variations in the finish grind position of said grinding wheel, said truing control means including first means for providing an output signal in response to the grinding of each of the workpieces in turn, second means for providing an output signal in response to the grinding of a number of workpieces which varies as a function of changes in the finish grind position of the grinding wheel, and third means for receiving output signals from said first and second means and for effecting the initiation of a wheel dressing cycle in response to the receipt of a predetermined number of output signals from said first and second means.
Claim 10
Dependent Claim
118 words
In a grinding machine according to claim 8 further including compensating means for advancing the grinding wheel relative to the base and toward the work support means by an amount equal to the amount the radius of the grinding wheel is reduced by the truing means during dressing of the grinding wheel whereby an initial position of the cutting face of the wheel is reestablished at a substantially constant distance from work support means and the finish size of the workpiece, said second means including means for providing an output signal in response to the grinding of a number of workpieces which decreases as the distance through which the grinding wheel is advanced by said compensating means increases.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |