Apparatus and method for dressing grinding wheels

Claim 2

In combination with a grinding machine having a grinding wheel with a peripheral grinding face rotatably supported for rotation about an axis of rotation; means for rotating and progressively changing angular velocity of the grinding wheel in accordance with changing grinding wheel diameter to maintain a substantially constant peripheral surface speed of the grinding face; means for dressing the grinding face including a tool carrier movable toward and away from the axis of rotation, a dressing tool on and movable with the tool carrier, tool carrier means for supporting the tool carrier and the dressing tool movable relative to and into operative relation to dress and peripheral grinding face of the grinding wheel to a predetermined shape, means for feeding the tool carrier and the dressing tool a predetermined increment relative to the tool carrier means, the grinding face, and toward the axis of rotation to dress and thereby reduce the diameter of the grinding wheel accordingly, means for traversing the tool carrier means and the dressing tool across the grinding face in a longitudinal direction of the axis of rotation of the grinding wheel; wherein the improvement comprises: variable drive means operatively connected to the means for traversing the dressing tool; and speed control means operatively connected to the variable drive means and responsive to radial movement and distance of the dressing tool from the axis of rotation of the grinding wheel for determining a speed And varying the speed of the variable means for traversing the truing tool as an inverse function of changes in the radial distance of the truing tool from the axis of rotation of the grinding wheel.

Claim 3

The combination according to claim 1 wherein the variable drive means for traversing the dressing tool comprises: a reversible fluid motor operatively connected to the tool carrier means; means for supplying and conveying fluid under pressure to drive the fluid motor; and directional control means for selectively directing the fluid under pressure to drive the reversible fluid motor in opposite directions.

Claim 4

The combination according to claim 1 wherein the variable drive means comprises: a reversible variable speed electric motor having a drive shaft operatively connected to the tool carrier means; means for supplying and conveying electrical energy to drive the electric motor; and directional control means for selectively directing the electrical energy to drive the reversible electric motor in opposite directions of rotation.

Claim 5

In combination with a grinding machine having a grinding wheel with a peripheral grinding face rotatably supported for rotation about an axis of rotation; means for rotating and progressively changing angular velocity of the grinding wheel in accordance with changing grinding wheel diameter to maintain a substantially constant peripheral surface speed of the grinding face; means for dressing the grinding face including a tool carrier movable toward and away from the axis of rotation, a dressing tool on and movable with the tool carrier, tool carrier means for supporting the tool carrier and the dressing tool movable relative to and into operative relation to dress the peripheral grinding face of the grinding wheel to a predetermined shape, means for feeding the tool carrier and the dressing tool a predetermined increment relative to the tool carrier means, the grinding face, and toward the axis of rotation to dress and thereby reduce the diameter of the grinding wheel accordingly, means for traversing the tool carrier means and the dressing tool across the grinding face in a longitudinal direction of the axis of rotation of the grinding wheel; wherein the improvement comprises: variable drive means operatively connected to the means for traversing the dressing tool; speed control means operatively connected to the variable drive means and responsive to radial movement and distance of the dressing tool from the axis of rotation of the grinding wheel for determining a speed and varying the speed of the variable means for traversing the truing tool to maintain and repeatedly produce a substantially constant uniformly dressed surface finish on the grinding face during the life of the wheel in accordance with the changes in the radial distance of the truing tool from the axis of rotation and diameter of the grinding wheel; said variable drive means for traversing the dressing tool comprises: a reversible fluid motor operatively connected to the tool carrier means; means for supplying and conveying fluid under pressure to drive the fluid motor; and directional control means for selectively directing the fluid under pressure to drive the reversible fluid motor in opposite directions; and said speed control means comprises: a fluid flow control valve having a valve housing, an inlet port, and an outlet port spaced from the inlet port; a speed control member in and movable relative to the housing and having an orifice of constantly varing area extending between the inlet and the outlet ports; and actuating means connected to and responsive to radial movement and position of the tool carrier and the dressing tool relative to the axis of rotation for causing relative movement between the housing and the speed control member and changing the area of the orifice, flow of fluid through the orifice, and tHe speed of the fluid motor in response to the radial movement and position of the dressing tool relative to the axis of rotation.

Claim 6

In combination with a grinding machine having a grinding wheel with a peripheral grinding face rotatably supported for rotation about an axis of rotation; means for rotating and progressively changing angular velocity of the grinding wheel in accordance with changing grinding wheel diameter to maintain a substantially constant peripheral surface speed of the grinding face; means for dressing the grinding face including a tool carrier movable toward and away from the axis of rotation, a dressing tool on and movable with the tool carrier, tool carrier means for supporting the tool carrier and the dressing tool movable relative to and into operative relation to dress the peripheral grinding face of the grinding wheel to a predetermined shape, means for feeding the tool carrier and the dressing tool a predetermined increment relative to the tool carrier means, the grinding face, and toward the axis of rotation to dress and thereby reduce the diameter of the grinding wheel accordingly, means for traversing the tool carrier means and the dressing tool across the grinding face in a longitudinal direction of the axis of rotation of the grinding wheel; wherein the improvement comprises: variable drive means operatively connected to the means for traversing the dressing tool; speed control means operatively connected to the variable drive means and responsive to radial movement and distance of the dressing tool from the axis of rotation of the grinding wheel for determining a speed and varying the speed of the variable means for traversing the truing tool to maintain and repeatedly produce a substantially constant uniformly dressed surface finish on the grinding face during the life of the wheel in accordance with the changes in the radial distance of the truing tool from the axis of rotation and diameter of the grinding wheel; said variable drive means for traversing the dressing tool comprises: a reversible fluid motor operatively connected to the tool carrier means; means for supplying and conveying fluid under pressure to drive the fluid motor; and directional control means for selectively directing the fluid under pressure to drive the reversible fluid motor in opposite directions; and said speed control means comprises: a fluid flow control valve having a valve housing, an inlet port, and an outlet port spaced from the inlet port; a speed control member in and movable relative to the housing and having an orifice of constantly varing area extending between the inlet and the outlet ports; and actuating means connected to and responsive to radial movement and position of the tool carrier and the dressing tool relative to the axis of rotation for causing relative movement between the housing and the speed control member and changing the area of the orifice, flow of fluid through the orifice, and tHe speed of the fluid motor in response to the radial movement and position of the dressing tool relative to the axis of rotation.

Claim 7

In combination with a grinding machine having a grinding wheel with a peripheral grinding face rotatably supported for rotation about an axis of rotation; means for rotating and progressively changing angular velocity of the grinding wheel in accordance with changing grinding wheel diameter to maintain a substantially constant peripheral surface speed of the grinding face; means for dressing the grinding face including a tool carrier movable toward and away from the axis of rotation, a dressing tool on and movable with the tool carrier, tool carrier means for supporting the tool carrier and the dressing tool movable relative to and into operative relation to dress the peripheral grinding face of the grinding wheel to a predetermined shape, means for feeding the tool carrier and the dressing tool a predetermined increment relative to the tool carrier means, the grinding face, and toward the axis of rotation to dress and thereby reduce the diameter of the grinding wheel accordingly, means for traversing the tool carrier means and the dressing tool across the grinding face in a longitudinal direction of the axis of rotation of the grinding wheel; wherein the improvement comprises: variable drive means operatively connected to the means for traversing the dressing tool; speed control means operatively connected to the variable drive means and responsive to radial movement and distance of the dressing tool from the axis of rotation of the grinding wheel for determining a speed and varying the speed of the variable means for traversing the truing tool to maintain and repeatedly produce a substantially constant uniformly dressed surface finish on the grinding face during the life of the wheel in accordance with the changes in the radial distance of the truing tool from the axis of rotation and diameter of the grinding wheel, said variable drive means for traversing the dressing tool comprises: a reversible fluid motor operatively connected to the tool carrier means; means for supplying and conveying fluid under pressure to drive the fluid motor; and directional control means for selectively directing the fluid under pressure to drive the reversible fluid motor in opposite directions; and said speed control means comprises: a fluid flow control valve having a valve housing, fixed against radial movement relative to the axis of rotation, attached to and movable with the tool carrier means in the longitudinal direction having a bore in the housing, an inlet port in the housing leading into the bore, an outlet port in the housing leading from the bore; a speed control member movable in the bore relative to the housing and having a slot of constantly varying depth extending between the inlet and outlet ports in the housing; a needle member in the valve housing having an end portion extending into the slot and providing an orifice between the speed control member and the needle of a size determined by the position of the speed control member relative to the needle and through which the fluid flows at a rate determining the speed of the fluid motor and the dressing tool across the grinding face; and actuating means connected to the tool carrier and the speed control member for shifting the speed control member relative to the needle and changing the size of the orifice in response to the radial movement and position of the tool carrier and dressing tool relative to the axis of rotation.

Claim 8

In combination with a grinding machine having a grinding wheel with a peripheral grinding face rotatably supported for rotation about an axis of rotation; means for rotating and progressively changing angular velocity of the grinding wheel in accordance with changing grinding wheel diameter to maintain a substantially constant peripheral surface speed of the grinding face; means for dressing the grinding face including a tool carrier movable toward and away from the axis of rotation, a dressing tool on and movable with the tool carrier, tool carrier means for supporting the tool carrier and the dressing tool movable relative to and into operative relation to dress the peripheral grinding face of the grinding wheel to a predetermined shape, means for feeding the tool carrier and the dressing tool a predetermined increment relative to the tool carrier means, the grinding face, and toward the axis of rotation to dress and thereby reduce the diameter of the grinding wheel accordingly, means for traversing the tool carrier means and the dressing tool across the grinding face in a longitudinal direction of the axis of rotation of the grinding wheel; wherein the improvement comprises: variable drive means operatively connected to the means for traversing the dressing tool; speed control means operatively connected to the variable drive means and responsive to radial movement and distance of the dressing tool from the axis of rotation of the grinding wheel for determining a speed and varying the speed of the variable means for traversing the truing tool to maintain and repeatedly produce a substantially constant uniformly dressed surface finish on the grinding face during the life of the wheel in accordance with the changes in the radial distance of the truing tool from the axis of rotation and diameter of the grinding wheel, said variable drive means for traversing the dressing tool comprises: a reversible fluid motor operatively connected to the tool carrier means; means for supplying and conveying fluid under pressure to drive the fluid motor; and directional control means for selectively directing the fluid under pressure to drive the reversible fluid motor in opposite directions; and said speed control means comprises: a fluid flow control valve having a valve housing, fixed against radial movement relative to the axis of rotation, attached to and movable with the tool carrier means in the longitudinal direction having a bore in the housing, an inlet port in the housing leading into the bore, an outlet port in the housing leading from the bore; a speed control member movable in the bore relative to the housing and having a slot of constantly varying depth extending between the inlet and outlet ports in the housing; a needle member in the valve housing having an end portion extending into the slot and providing an orifice between the speed control member and the needle of a size determined by the position of the speed control member relative to the needle and through which the fluid flows at a rate determining the speed of the fluid motor and the dressing tool across the grinding face; and actuating means connected to the tool carrier and the speed control member for shifting the speed control member relative to the needle and changing the size of the orifice in response to the radial movement and position of the tool carrier and dressing tool relative to the axis of rotation.

Claim 9

The combination according to claim 5 wherein the actuating means comprises: a rack bar with gear teeth thereon fixed to and movable with the tool carrier relative to the axis of rotation of the grinding wheel; a drive gear with gear teeth meshing with the gear teeth on the rack bar and rotatably mounted on the housing; and a driven gear fixed to and rotatably driven by the drive gear and having gear teeth meshing with rack teeth on the speed control member.

Claim 10

The combination according to claim 6 wherein the reversible fluid motor is a linear fluid motor comprising: a cylinder, a piston slideable in the cylinder; and a piston rod connected to the piston and the tool carrier means.

Claim 11

The combination according to claim 6 wherein the variable drive means comprises: a reversible rotary fluid motor having a rotatable drive shaft; and a rotatable feed screw coupled to the drive shaft and threadedly engaging tool carrier means for traversing the dressing tool across the grinding face.

Claim 12

The combination according to claim 8 wherein the variable drive means further comprises: a gear reduction mechanism coupled to the drive shaft and the feed screw.

Claim 13

In combination with a grinding machine having a grinding wheel with a peripheral grinding face rotatably supported for rotation about an axis of rotation; means for rotating and progressively changing angular velocity of the grinding wheel in accordance with changing grinding wheel diameter to maintain a substantially constant peripheral surface speed of the grinding face; means for dressing the grinding face including a tool carrier movable toward and away from the axis of rotation, a dressing tool on and movable with the tool carrier, tool carrier means for supporting the tool carrier and the dressing tool movable relative to and into operative relation to dress the peripheral grinding face of the grinding wheel to a predetermined shape, means for feeding the tool carrier and the dressing tool a predetermined increment relative to the tool carrier means, the grinding face, and toward the axis of rotation to dress and thereby reduce the diameter of the grinding wheel accordingly, means for traversing the tool carrier means and the dressing tool across the grinding face in a longitudinal direction of the axis of rotation of the grinding wheel; wherein the improvement comprises: variable drive means operatively connected to the means for traversing the dressing tool; speed control means operatively connected to the variable drive means and responsive to raidal movement and distance of the dressing tool from the axis of rotation of the grinding wheel for determining a speed and varying the speed of the variable means for traversing the truing tool to maintain and repeatedly produce a substantially constant uniformly dressed surface finish on the grinding face during the life of the wheel in accordance with the changes in the radial distance of the truing tool from the axis of rotation and diameter of the grinding wheel; said variable drive means comprises: a reversible variable speed electric motor having a drive shaft operatively connected to the tool carrier means; means for supplying and conveying electrical energy to drive the electric motor; and directional control means for selectively directing the electrical energy to drive the reversible electric motor in opposite directions of rotation; and said speed control means comprises: an electrical control circuit; a rheostat connected to the electrical circuit and having a variable resistance element connected electrically to the electrical motor, and a movable contact element engaging and movable relative to the resistance element; actuating means connected to the tool carrier and the movable contact element for shifting the movable contact element relative to the resistance element to vary the resistance and rotational speed of the electric motor and the dressing tool across the grinding face in response to the radial movement and position of the tool carrier and dressing tool relative to the axis of rotation.

Claim 14

In combination with a grinding machine having a grinding wheel with a peripheral grinding face rotatably supported for rotation about an axis of rotation; means for rotating and progressively changing angular velocity of the grinding wheel in accordance with changing grinding wheel diameter to maintain a substantially constant peripheral surface speed of the grinding face; means for dressing the grinding face including a tool carrier movable toward and away from the axis of rotation, a dressing tool on and movable with the tool carrier, tool carrier means for supporting the tool carrier and the dressing tool movable relative to and into operative relation to dress the peripheral grinding face of the grinding wheel to a predetermined shape, means for feeding the tool carrier and the dressing tool a predetermined increment relative to the tool carrier means, the grinding face, and toward the axis of rotation to dress and thereby reduce the diameter of the grinding wheel accordingly, means for traversing the tool carrier means and the dressing tool across the grinding face in a longitudinal direction of the axis of rotation of the grinding wheel; wherein the improvement comprises: variable drive means operatively connected to the means for traversing the dressing tool; speed control means operatively connected to the variable drive means and responsive to raidal movement and distance of the dressing tool from the axis of rotation of the grinding wheel for determining a speed and varying the speed of the variable means for traversing the truing tool to maintain and repeatedly produce a substantially constant uniformly dressed surface finish on the grinding face during the life of the wheel in accordance with the changes in the radial distance of the truing tool from the axis of rotation and diameter of the grinding wheel; said variable drive means comprises: a reversible variable speed electric motor having a drive shaft operatively connected to the tool carrier means; means for supplying and conveying electrical energy to drive the electric motor; and directional control means for selectively directing the electrical energy to drive the reversible electric motor in opposite directions of rotation; and said speed control means comprises: an electrical control circuit; a rheostat connected to the electrical circuit and having a variable resistance element connected electrically to the electrical motor, and a movable contact element engaging and movable relative to the resistance element; actuating means connected to the tool carrier and the movable contact element for shifting the movable contact element relative to the resistance element to vary the resistance and rotational speed of the electric motor and the dressing tool across the grinding face in response to the radial movement and position of the tool carrier and dressing tool relative to the axis of rotation.

Claim 15

The combination according to claim 10 wherein the variable drive means further comprises: a rotatable feed screw coupled to the drive shaft of The electric motor and threadedly engaging the tool carrier means for traversing the dressing tool across the grinding face.

Claim 16

The combination according to claim 11 wherein the variable drive means further comprises: a gear reduction mechanism coupled to and situated between the drive shaft of the electric motor and the feed screw.

Claim 19

An apparatus as set forth in claim 13 wherein said motor means includes a fluid motor, and said control means includes conduit means for conducting fluid to and from said fluid motor and means for varying the rate of fluid flow through said conduit means as a function of variations in the distance between the dressing tool and the axis of rotation of the grinding wheel.

Claim 24

An apparatus as set forth in claim 16 wherein said means for varying the rate at which electrical energy is conducted to said electrical motor includes a rheostat and means for actuating said rheostat to an extent which varies as a function of variations in the distance between the dressing tool and the axis of rotation of the grinding wheel.