US3654800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-pointing thread rolling dies
Assignee: Pratt and Whitney Co Inc
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Filing: 1969-11-24
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Granted: 1972-04-11
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Expires: 1989-11-24
Abstract
Abstract A pair of self-pointing thread rolling dies is illustrated for forming a threaded and pointed screw from an unpointed blank having excess material in the shank. During the rolling operation the excess material is formed into a slug which is separated from the finished screw. Each die includes a slug forming surface formed with driving serrations thereon. The projections of the serrations into the plane of movement of the axis of the blank are inclined with respect to a referenced plane perpendicular to the direction of relative die movement. The inclined serrations provide a smoother drive for the slug and improve the uniformity of location of slug separation so that the uniformity of the screws formed by the dies is improved. The point burning of the screw is also reduced and die life is improved. In one embodiment the serrations are inclined in the same general direction with respect to the referenced plane and in another embodiment, they are inclined in opposite directions with respect thereto.
Inventors
- 👤 Herbert L Yankee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:55
CPC Classifications
B; B21; B21H; B21H3/00; B21H3/02; B21H3/06
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
166 words
A pair of thread rolling dies for forming a threaded and pointed screw from a blank having a generally cylindrical shank with excess material therein comprising a pair of die members adapted to be positioned opposite each other and moved relative to each other in a first direction to roll a blank therebetween with the axis of said blank in a first plane substantially parallel to said one direction, said dies each being formed with thread and point forming surfaces operable to point said shank and form threads therealong, each of said dies also being formed with slug forming surfaces operable to form said excess material into a slug and separate said slug from said screw, said slug forming surfaces each being formed with serrations therein which are spaced therealong in said first direction, said serrations of at least one die being angulated so that their projections in said first plane extend at an angle with respect to a referenced plane perpendicular to said first direction.
Claim 2
Dependent Claim
166 words
A pair of thread rolling dies for forming a threaded and pointed screw from a blank having a generally cylindrical shank with excess material therein comprising a pair of die members adapted to be positioned opposite each other and moved relative to each other in a first direction to roll a blank therebetween with the axis of said blank in a first plane substantially parallel to said one direction, said dies each being formed with thread and point forming surfaces operable to point said shank and form threads therealong, each of said dies also being formed with slug forming surfaces operable to form said excess material into a slug and separate said slug from said screw, said slug forming surfaces each being formed with serrations therein which are spaced therealong in said first direction, said serrations of at least one die being angulated so that their projections in said first plane extend at an angle with respect to a referenced plane perpendicular to said first direction.
Claim 3
Dependent Claim
40 words
A pair of thread rolling dies as set forth in claim 1 wherein said serrations on both of said dies are angulated so that their projections in said first plane extend at an angle with respect to said referenced plane.
Claim 4
Dependent Claim
27 words
A pair of thread rolling dies as set forth in claim 1 wherein said angle of said serrations on said one die is between 15* and 45*.
Claim 5
Dependent Claim
26 words
A pair of thread rolling dies as set forth in claim 3 wherein said angle of said serrations of said one die is at least 20*.
Claim 6
Dependent Claim
27 words
A pair of thread rolling dies as set forth in claim 1 wherein said one die is longer than the other die of said pair of dies.
Claim 7
Dependent Claim
44 words
A pair of thread rolling dies as set forth in claim 5 wherein said thread and point forming surfaces are provided with thread forming grooves inclined with respect to said referenced plane in the same general direction as said serrations on said one die.
Claim 8
Dependent Claim
171 words
A pair of thread rolling dies for forming a threadeD and pointed screw from a blank having a generally cylindrical shank with excess material therein comprising a pair of die members adapted to be positioned opposite each other and moved relative to each other in a first direction to roll a blank therebetween with the axis of said blank in a first plane substantially parallel to said one direction, said dies each being formed with thread and point forming surfaces operable to point said shank and form threads therealong, each of said dies also being formed with slug forming surfaces operable to form said excess material into a slug and separate said slug from said screw, said slug forming surfaces each being formed with serrations therein which are spaced therealong in said first direction, said serrations being angulated so that their projections in said first plane extend at angles with respect to a referenced plane perpendicular to said first direction and are inclined in the same general direction with respect thereto.
Claim 9
Dependent Claim
171 words
A pair of thread rolling dies for forming a threadeD and pointed screw from a blank having a generally cylindrical shank with excess material therein comprising a pair of die members adapted to be positioned opposite each other and moved relative to each other in a first direction to roll a blank therebetween with the axis of said blank in a first plane substantially parallel to said one direction, said dies each being formed with thread and point forming surfaces operable to point said shank and form threads therealong, each of said dies also being formed with slug forming surfaces operable to form said excess material into a slug and separate said slug from said screw, said slug forming surfaces each being formed with serrations therein which are spaced therealong in said first direction, said serrations being angulated so that their projections in said first plane extend at angles with respect to a referenced plane perpendicular to said first direction and are inclined in the same general direction with respect thereto.
Claim 10
Dependent Claim
35 words
A pair of thread rolling dies as set forth in claim 7 wherein said angle of said serrations of one die is equal to said angle of said serrations on the other of said dies.
Claim 11
Dependent Claim
28 words
A pair of thread rolling dies as set forth in claim 8 wherein said angle of said serrations on both of said dies is between 15* and 45*.
Claim 12
Dependent Claim
27 words
A pair of thread rolling dies as set forth in claim 9 wherein said angle of said serrations is at least 20* on both of said dies.
Claim 13
Dependent Claim
26 words
A pair of thread rolling dies as set forth in claim 7 wherein said angle of said serrations on one die is between 15* and 45*.
Claim 14
Dependent Claim
27 words
A pair of thread rolling dies as set forth in claim 11 wherein said angle of said serrations on said one die is at least 20* .
Claim 15
Dependent Claim
170 words
A pair of thread rolling dies for forming a threaded and pointed screw from a blank having a generally cylindrical shank with excess material therein comprising a pair of die members adapted to be positioned opposite each other and moved relative to each other in a first direction to roll a blank therebetween with the axis of said blank in a first plane substantially parallel to said one direction, said dies each being formed with thread and point forming surfaces operable to point said shank and form threads therealong, each of said dies also being formed with slug forming surfaces operable to form said excess material into a slug and separate said slug from said screw, said slug forming surfaces each being formed with serrations therein which are spaced therealong in said first direction, said serrations being angulated to that their projections in said first plane extend at angles with respect to a referenced plane perpendicular to said first direction and are inclined in generally opposite directions with respect thereto.
Claim 16
Dependent Claim
170 words
A pair of thread rolling dies for forming a threaded and pointed screw from a blank having a generally cylindrical shank with excess material therein comprising a pair of die members adapted to be positioned opposite each other and moved relative to each other in a first direction to roll a blank therebetween with the axis of said blank in a first plane substantially parallel to said one direction, said dies each being formed with thread and point forming surfaces operable to point said shank and form threads therealong, each of said dies also being formed with slug forming surfaces operable to form said excess material into a slug and separate said slug from said screw, said slug forming surfaces each being formed with serrations therein which are spaced therealong in said first direction, said serrations being angulated to that their projections in said first plane extend at angles with respect to a referenced plane perpendicular to said first direction and are inclined in generally opposite directions with respect thereto.
Claim 17
Dependent Claim
34 words
A pair of thread rolling dies as set forth in claim 13 wherein said angle of said serrations on one die is substantially equal to said angle of said serrations on the other die.
Claim 18
Dependent Claim
23 words
A pair of thread rolling dies as set forth in claim 14 wherein said angle of said serrations is between 15* and 45*.
Claim 19
Dependent Claim
22 words
A pair of thread rolling dies as set forth in claim 15 wherein said angle of said serrations is at least 20*.
Claim 20
Dependent Claim
26 words
A pair of thread rolling dies as set forth in claim 13 wherein said angle of said serrations on one die is between 15* and 45*.
Claim 21
Dependent Claim
29 words
A pair of thread rolling dies as set forth in claim 17 wherein said angle of said serrations on said one die is at least equal to 20* .
Claim 22
Dependent Claim
158 words
A pair of thread rolling dies for forming a threaded and pointed screw from a blank having a generally cylindrical shank with excess material therein comprising a pair of die members adapted to be positioned opposite each other and moved relative to each other in a first direction to roll a blank therebetween, said dies each being formed with thread and point forming surfaces operable to point said shank and form threads therealong, each of said dies also being formeD with slug forming surfaces operable to form said excess material into a slug and separate said slug from said screw, said slug forming surfaces each being formed with surface irregularities shaped and located along said slug forming surface to provide a sufficient drive with the slug portion of said blank to cause said slug portion to be driven along said dies with the remainder of said blank without inducing sufficiently abrupt stresses to cause nonuniformity in slug separation.
Claim 23
Dependent Claim
158 words
A pair of thread rolling dies for forming a threaded and pointed screw from a blank having a generally cylindrical shank with excess material therein comprising a pair of die members adapted to be positioned opposite each other and moved relative to each other in a first direction to roll a blank therebetween, said dies each being formed with thread and point forming surfaces operable to point said shank and form threads therealong, each of said dies also being formeD with slug forming surfaces operable to form said excess material into a slug and separate said slug from said screw, said slug forming surfaces each being formed with surface irregularities shaped and located along said slug forming surface to provide a sufficient drive with the slug portion of said blank to cause said slug portion to be driven along said dies with the remainder of said blank without inducing sufficiently abrupt stresses to cause nonuniformity in slug separation.
Claim 24
Dependent Claim
42 words
A pair of thread rolling dies as set forth in claim 19 wherein said surface irregularities are serrations which are angulated to engage the slug first at one end and thereafter progressively engage said slug along its length from said one end.
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) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |