Self-locking fastener and method of making same

Claim 2

A threaded metal fastening member for screw-threaded cooperation with a mating threaded part having a plating of hard metal localized of the threaded portion thereof, the plating being of a circumferential extent of less than 180* and being of a thickness sufficient to force the opposite side of the threaded portion into pressure contact with the mating part for frictional self-locking cooperation therewith, the metal of the plating being harder than that of the mating threaded part.

Claim 3

A fastening member as set forth in claim 1 in which the plating is a nickel plating.

Claim 4

A fastening member as set forth in claim 1 in which the plating extends over a plurality of turns of the screw thread of the member.

Claim 5

In a metal fastener assembly wherein a first inner fastener member has an external screw thread and a second outer fastener member has an internal screw thread to engage the external screw thread, the improvement for self-locking action of the two screw threads, comprising: plating extending over a minor portion of the circumference of one of the two screw threads to force the two members into eccentric relationship to force the two screw threads into mutual tangential contact in a friction locking zone diametrically opposite from the plating when the tolerance clearance between the two screw threads is maximum; and said plating being of a metal hard enough to be substantially invulnerable to deformation by the screw thread of the other of the two members to cause the outer fastener member to deform elastically to the general configuration of an ellipse to compensate for less than the maximum tolerance clearance.

Claim 6

In a metal fastener assembly wherein a first inner fastener member has an external screw thread and a second outer fastener member has an internal screw thread to engage the external screw thread, the improvement for self-locking action of the two screw threads, comprising: plating extending over a minor portion of the circumference of one of the two screw threads to force the two members into eccentric relationship to force the two screw threads into mutual tangential contact in a friction locking zone diametrically opposite from the plating when the tolerance clearance between the two screw threads is maximum; and said plating being of a metal hard enough to be substantially invulnerable to deformation by the screw thread of the other of the two members to cause the outer fastener member to deform elastically to the general configuration of an ellipse to compensate for less than the maximum tolerance clearance.

Claim 7

An improvement as set forth in claim 4 in which said plating comprises two circumferentially spaced deposits of plating within said minor portion of the circumference.

Claim 8

In a metal screw member having an external screw thread to engage an internal screw thread of a complementary member, the improvement for self-locking action of the two members, comprising: plating extending over a minor portion of the circumference of said external screw thread of a thickness to force the two members into eccentric relationship to force the two screw threads into mutual tangential contact in a friction locking zone diametrically opposite from the plating when the tolerance clearance between the two screw threads is maximum; and said plating being of a metal hard enough to be substantially invulnerable to deformation by the screw thread of the other of the complementary member to cause the complementary member to deform elastically to the general configuration of an ellipse to compensate for less than the maximum tolerance clearance.

Claim 9

In a metal screw member having an external screw thread to engage an internal screw thread of a complementary member, the improvement for self-locking action of the two members, comprising: plating extending over a minor portion of the circumference of said external screw thread of a thickness to force the two members into eccentric relationship to force the two screw threads into mutual tangential contact in a friction locking zone diametrically opposite from the plating when the tolerance clearance between the two screw threads is maximum; and said plating being of a metal hard enough to be substantially invulnerable to deformation by the screw thread of the other of the complementary member to cause the complementary member to deform elastically to the general configuration of an ellipse to compensate for less than the maximum tolerance clearance.

Claim 10

In a metal fastener assembly wherein a screw member has an external screw thread and a complementary nut member has an internal screw thread to engage the external screw thread with a given range of tolerance clearance between the two screw threads, the improvement for self-locking action of the two screw threads, comprising: a plating deposit on one of the two screw threads of a circumferential extent of substantially less than 180* to force the two members into eccentric relationship; said plating deposit being a metal of sufficient hardness to be substantially invulnerable to deformation by the other of the two screw threads; and said plating deposit being of a thickness to compensate for the maximum clearance in said range to force the two screw threads into mutual contact in a frictional locking zone diametrically opposite from the plating deposit when the clearance between the two screw threads is at said maximum, whereby compensation for the clearance being only slightly less than said maximum is provided at least in part by mutual frictional polishing of the two screw threads and compensation for the clearance being greatly less than said maximum is provided in part by elastic deformation of the nut member into the configuration of an ellipse with the major axis of the ellipse intersecting said fricTional locking zone.

Claim 11

In a metal fastener assembly wherein a screw member has an external screw thread and a complementary nut member has an internal screw thread to engage the external screw thread with a given range of tolerance clearance between the two screw threads, the improvement for self-locking action of the two screw threads, comprising: a plating deposit on one of the two screw threads of a circumferential extent of substantially less than 180* to force the two members into eccentric relationship; said plating deposit being a metal of sufficient hardness to be substantially invulnerable to deformation by the other of the two screw threads; and said plating deposit being of a thickness to compensate for the maximum clearance in said range to force the two screw threads into mutual contact in a frictional locking zone diametrically opposite from the plating deposit when the clearance between the two screw threads is at said maximum, whereby compensation for the clearance being only slightly less than said maximum is provided at least in part by mutual frictional polishing of the two screw threads and compensation for the clearance being greatly less than said maximum is provided in part by elastic deformation of the nut member into the configuration of an ellipse with the major axis of the ellipse intersecting said fricTional locking zone.

Claim 12

An improvement as set forth in claim 7 in which the plating is on the external screw thread of the screw member.

Claim 13

An improvement as set forth in claim 7 in which the plating is on the internal screw thread of the nut member.

Claim 14

An improvement as set forth in claim 7: in which the two members are high class threaded members with fine threads; and in which the thickness of the plating is based on the relationship of a thickness of 50-60 percent of said maximum clearance when the effective circumferential extent of the patch is on the order of 20* - 40*, the thickness varying inversely with the circumferential extent of the patch.

Claim 15

An improvement as set forth in claim 7: in which the two members are high class threaded members with coarse threads; and in which the thickness of the plating is based on the relationship of a thickness of 55-65 percent of said maximum clearance when the effective circumferential extent of the patch is on the order of 20*-40*, the thickness varying inversely with the circumferential extent of the patch.