Thread grinder

A machine for grinding workpieces comprising a base, a wheelhead carried by said base for reciprocation in a straight line path and constructed and arranged to drive a grinding wheel with its axis of rotation extending essentially transversely to said straight line path of reciprocation, a workhead adapted to releasably receive and rotate a workpiece and constructed and arranged to position the workpiece so that the point of contact between such workpiece and the grinding wheel is on one side of the centerline which intersects the axis of rotation of the wheel and extends parallel to such straight line path of reciprocation of said wheelhead, a grinding wheel dresser adapted to receive a dressing tool and constructed and arranged so that the point of contact between the dressing tool and the grinding wheel is located on the same side of the grinding wheel as the point of contact between the grinding wheel and the workpiece, on the other side of such centerline intersecting the axis of rotation of the grinding wheel and extending parallel to such straight line path of reciprocation of the wheelhead, and symmetrical about said centerline with the point of contact between the grinding wheel and the workpiece, a programmer for feeding the grinding wheel toward the workpiece carried by the workhead for making successively deeper material removal cuts along the same path through the workpiece having a first element carried by said base, a second element operably connected with said wheelhead for movement therewith, one of said elements having a threaded portion thereof engaging a mating portion of said other element and constructed and arranged so that relative rotation of said elements in one direction advances the grinding wheel carried by said wheelhead toward the workpiece carried by said workhead and relative rotation in the opposite direction retracts the grinding wheel away from the workpiece, a positive stop associated with one of said elements to limit the extent to which it can be rotated to feed the grinding wheel toward the workpiece, a dial associated with said one element for rotation in synchronization with said one element, a driver operably associated with said dial and said one element for rotating them in synchronization with each other and rotating said one element in one direction to move the grinding wheel toward the workpiece, at least one switch constructed and arranged to change states when actuated by a dog carried by said dial, a first dog carried by said dial and being positioned on said dial to actuate one of said switches when said drive has rotated said one element to the full extent permitted by said positive stop, at least one second dog releasably carried by said dial with each of said second dogs being carried on said dial in angularly spaced apart relation to each other and said first dog to successively actuate one of said switches as said drive rotates said one element to advance the grinding wheel toward the workpiece, control means responsive to actuation of said switches and operatively associated with said drive to stop rotation of said one element and dial in response to actuation of said switches by each of said dogs so that the number of increments in which the grinding wheel is advanced toward the workpiece is a function of the number of said dogs carried by said dial and the extent of the advancement of the grinding wheel toward the workpiece for each increment is a function of the angular spacing of said dogs on said dial, and a second drive constructed and arranged to rotate said other element of said programmer without rotating said one element thereof in one direction to advance the grinding wheel toward the workpiece and in the opposite direction to retract the grinding wheel from the workpiece.

A machine for grinding workpieces comprising a base, a wheelhead carried by said base for reciprocation in a straight line path and constructed and arranged to drive a grinding wheel with its axis of rotation extending essentially transversely to said straight line path of reciprocation, a workhead adapted to releasably receive and rotate a workpiece and constructed and arranged to position the workpiece so that the point of contact between such workpiece and the grinding wheel is on one side of the centerline which intersects the axis of rotation of the wheel and extends parallel to such straight line path of reciprocation of said wheelhead, a grinding wheel dresser adapted to receive a dressing tool and constructed and arranged so that the point of contact between the dressing tool and the grinding wheel is located on the same side of the grinding wheel as the point of contact between the grinding wheel and the workpiece, on the other side of such centerline intersecting the axis of rotation of the grinding wheel and extending parallel to such straight line path of reciprocation of the wheelhead, and symmetrical about said centerline with the point of contact between the grinding wheel and the workpiece, a table carrying said workhead and carried by said base for reciprocating the workpiece carried by said workhead generally longitudinally with respect to the grinding wheel carried by said wheelhead, a drive constructed and arranged to move the table so that the workpiece is moved generally longitudinally under the grinding wheel in timed relation with rotation of the workpiece by the workhead, an a relief mechanism having a cam carried by said table and constructed and arranged to rotated in timed relation with rotation of the workpiece carried by the workhead, a fulcrum carried by said table, a lever arm received on said fulcrum, a follower carried by said lever arm and engagable with said cam, said lever arm being operatively associated with said workhead and constructed and arranged to move the workpiece carried by said workhead generally radially with respect to the wheel in response to rotary motion of said cam, said fulcrum being constructed and arranged to permit the point at which said arm pivots thereon to be shifted generally longitudinally of the arm, and an actuator constructed and arranged to move said fulcrum with respect to said arm to vary and adjust the extent to which the workpiece is moved generally radially toward and away from the grinding wheel by rotation of said cam.

A machine for grinding workpieces comprising a base, a wheelhead carried by said base for reciprocation in a straight line path and constructed and arranged to drive a grinding wheel with its axis of rotation extending essentially transversely to said straight line path of reciprocation, a workhead adapted to releasably receive and rotate a workpiece and constructed and arranged to position the workpiece so that the point of contact between such workpiece and the grinding wheel is on one side of the centerline which intersects the axis of rotation of the wheel and extends parallel to such straight line path of reciprocation of said wheelhead, a grinding wheel dresser adapted to receive a dressing tool and constructed and arranged so that the point of contact between the dressing tool and the grinding wheel is located on the same side of the grinding wheel as the point of contact between the grinding wheel and the workpiece, on the other side of such centerline intersecting the axis of rotation of the grinding wheel and extending parallel to such straight line path of reciprocation of the wheelhead, and symmetrical about said centerline with the point of contact between the grinding wheel and the workpiece, a table carrying said workhead and carried by said base for reciprocating the workpiece carried by said workhead generally longitudinally with respect to the grinding wheel carried by said wheelhead, a threaded lead screw carried by one of said table and said base, a nut threadily engaging said lead screw and carried by the other of said table and said base, a driven metric gear fixed to one of said lead screw and nut for rotation therewith, a driven English gear fixed to said one of said lead screw and nut for rotation therewith, a first drive disposed radially outward of said driven gears and in fixed circumferential and radial relationship to the axis of rotation of said driven gears, said first drive being constructed and arranged to releasably mount and journal for rotation a ratio gear driven in timed relationship with rotation of the workpiece carried by said workhead, a second drive spaced from said first drive and disposed radially outward of said driven gears and in fixed circumferential and radial relationship to the axis of rotation of said driven gears, said second drive being constructed and arranged to releasably mount and journal for rotation a first ratio gear driven in timed relationship with the rotation of the workpiece carried by said workhead, a metric coupler disposed generally radially between said first drive and said metric driven gear and constructed and arranged to be releasably secured in a range of circumferentially spaced positions about said metric driven gear, said metric coupler having a gear continuously meshed with said metric driven gear and being constructed and arranged to releasably mount and journal for rotation a second ratio gear to mesh with a first ratio gear received on said first drive and to rotate in unison with said gear continuously meshed with said metric driven gear, and an English coupler disposed generally radially between said English driven gear and said second drive and constructed and arranged to be releasably retained in a range of circumferentially spaced positions about said English driven gear, said English coupler having a gear continuously meshed with said English driven gear and being constructed and arranged to releasably mount and journal for rotation a second ratio gear to mesh with a first ratio gear received on said second drive and to rotate in unison with said gear continuously meshed with said English driven gear, whereby a selected pair of a first and a second ratio gears may be mounted respectively on one of said drives and one of said couplers and said one coupler moved circumferentially to mesh such ratio gears to drive said table in a predetermined timed relationship with rotation of the workpiece carried by said workhead to produce a desired pitch of threads grounds on the workpiece by the grinding wheel.

A machine for grinding workpieces comprising a base, a wheelhead carried by said base for reciprocation in a straight line path and constructed and arranged to drive a grinding wheel with its axis of rotation extending essentially transversely to said straight line path of reciprocation, and a programmer for feeding the grinding wheel toward a workpiece for making successively deeper material removal cuts along the same path through the workpiece, said programmer having a first element carried by said base, a second element operatively connected with said wheelhead for movement therewith, one of said elements having a threaded portion thereof engaging a mating portion of the other of said elements with said portions being constructed and arranged so that relative rotation of said elements in one direction advances the grinding wheel carried by said wheelhead toward the workpiece and relative rotation in the opposite direction retracts the grinding wheel away from the workpiece, a positive stop associated with one of said elements to limit the extent to which said one element can be rotated to feed the grinding wheel toward the workpiece, a dial associated with said one element for rotation in synchronization with said one element, a drive operably associated with said dial and said one element for rotating them in synchronization with each other and said one element in one direction to advance the grinding wheel toward the workpiece and in the opposite direction to retract the grinding wheel from the workpiece, at least one switch constructed and arranged to change states when actuated by at least one dog carried by said dial, a first dog carried by said dial and positioned thereon to actuate one of said switches when said drive has rotated said one element to feed the grinding wheel toward the workpiece to the full extent permitted by said positive stop, at least one second dog releasably carried by said dial with said second dogs being carried by said dial in angularly spaced apart relationship to each other and said first dog to successively actuate one of said switches as said drive rotates said one element to advance the grinding wheel toward the workpiece, and control means responsive to actuation of said switches and operatively associated with said drive to stop rotation of said one element and said dial in response to actuation of said switches by each of said dogs so that the number of increments in which the grinding wheel is advanced toward the workpiece is a function of the number of said dogs carried by said dial and the extent of the advancement of the grinding wheel towards the workpiece for each increment is a function of the angular spacing of said dogs on said dial, a grinding wheel dresser adapted to receive a dressing tool and constructed and arranged to advance the dressing tool into engagement with the grinding wheel and to retract and disengage the dressing tool from the grinding wheel, and a second drive constructed and arranged to rotate said second element of said programmer without rotating said first element thereof to advance the grinding wheel toward the workpiece in an amount equal to the decrease in the radius of the grinding wheel produced by operation of said grinding wheel dresser to thereby compensate the infeed of the grinding wheel for dressing of the grinding wheel.