US 4,613,260 AGranted

Thread cutting die head for power driven threading machines

AssigneeEmerson Electric Co.

InventorsRobert J. Hayes, Ronald M. Mahl

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Abstract

An annular thread cutting die head for a power driven threading machine is comprised of an annular support plate supporting a plurality of radially displacable thread cutting dies spaced apart about the axis of the die head, and an annular cam plate assembly coaxial with and pivotal relative to the support plate to radially displace the cutting dies. The cam plate assembly is spring biased to pivot relative to the support plate in the direction to radially retract the cutting dies, and is selectively operable relative to the support plate to achieve the cutting of a straight thread or to achieve the cutting of a tapered thread. In connection with the cutting of a tapered thread, receding replacement of the cutting tools is controlled by a unique cam arrangement on the machine carriage engaged by the cam plate assembly under the spring bias and independent of torque imposed on the die head during the threading operation.

Claims41

Dependent claims

An annular thread cutting die head for a power driven threading machine, said die head having an axis and an entrance end with respect to a workpiece to be threaded and comprising a plurality of thread cutting dies inwardly of said entrance end with respect to the direction of threading a workpiece, annular support plate means supporting said cutting dies for displacement radially inwardly and outwardly of said axis, annular cam plate means coaxial with said support plate means, said support plate means and cam plate means being interengaged for relative pivotal displacement in opposite directions about said axis, said cam plate means including means to displace said cutting dies radially inwardly and outwardly relative to said axis in response to said pivotal displacement in opposite directions about said axis, cam plate biasing interengaging said support plate means and said cam plate means and biasing said cam plate means to pivot about said axis in the direction to displace said cutting dies radially outwardly of said axis, said cutting dies having radially outwardmost positions relative to said axis, first latch means pivotally mounted on one of said support plate means and cam plate means, first keeper means on the other of said plate means, said latch means and keeper means releaseably interengaging said support plate means and cam plate means in a fixed relative angular position therebetween against the bias of said cam plate biasing means and in which angular position said cutting dies are positioned radially inwardly of said outwardmost positions, and said first latch means including actuator means adjacent said entrance end and engaged by a workpiece to disengage said first latch means from said first keeper means as said workpiece approaches said cutting dies in said direction of threading.

Threading apparatus for a threading machine having an axis, comprising a pair of support rails parallel to and laterally spaced from said axis, carriage means supported on said rails for movement in axially opposite directions therealong, one of said directions being a threading direction, die head means mounted on said carriage means for movement therewith in said opposite directions, said die head means including thread cutting dies and plate means pivotal relative to said axis to radially displace said cutting dies to cut a thread of predetermined length and taper on an end of a workpiece during movement of said carriage means in said threading direction, ramp means for controlling said length and taper, said ramp means being mounted on said carriage means adjacent one of said support rails for vertical displacement relative to said carriage means between upper and lower positions and for axial displacement with and relative to said carriage means, said plate means including actuator means for displacing said ramp means from said upper to said lower position, and ramp drive means on said carriage means engaging said ramp means in said lower position thereof to displace said ramp means axially relative to said carriage means during movement of said carriage means in said threading direction.

Dependencies are inferred from the claim text.