Patent EA-000161-B1 (EA)
Title: Anti-cross threading fastener
IPC: F16B33/02
Filed: 1996-07-19
Abstract: 1. An anti-cross threading fastener (10, 36) having first and second ends and r plurality of threads (20, 30) having first minor and major diameters, is characterized by at least one transitional thread (24, 34) having second major and minor diameters, wherein the difference between the first major and minor diameters is greater than the difference between the second major and minor diameters, said transitional thread (24, 34) being proximate the first end of said fastener (10, 36) and having a transitional surface (54) from the second minor diameter to the second major diameter, wherein the transitional surface (54) of the at least one transitional thread (24, 34) is adapted to cam over mating threads (20, 30) of a mating member (10, 36) whereby the longitudinal axes of said fastener (10, 36) and said mating member (10, 36) become substantially collinearly aligned. 2. The anti-cross threading fastener of Claim 1, wherein the at least one transitional thread (24) having a transitional surface (54) is a plurality of threads (24) having transitional surfaces (54) from the second minor diameter to the second major diameter. 3. The anti-cross threading fastener of Claim 1, further comprising at least one other transitional thread (24, 44) proximate the second end of said fastener (10, 46), wherein said at least one other transitional thread (24, 44) lias third minor and major diameters and the difference between the first major and minor diameters is greater than the difference between the third major and minor diameters, and wherein said at least one other transitional thread (24, 44) has a transitional surface (54) from the third minor diameter to the third major diameter, wherein the transitional surface (54) of the at least one other transitional thread (24, 44) is adapted to cam over mating threads of another mating member (10, 46) whereby the longitudinal axis of said fastener (10, 46) and said another mating member (10, 46) become substantially collinearly aligned. 4. The anti-cross threading fastener of Claim 1, characterized by a circular opening (32) inside the fastener (36), the opening (32) running longitudinally to the length; and wherein said plurality of threads (30) and said at least one transitional thread (34) arc inside said circular opening (32). 5. The anti-cross threading fastener of Claim 1, wherein said plurality of threads (20) and said at least one transitional thread (24) are external threads. 6. The anti-cross threading fastener of Claim 5, further characterized by a protruding diameter member (18) attached to and collinear with the first end of said fastener (10), said protruding diameter member (18) restricting the presentation angle between said fastener (10) and said mating member (36). 7. The anti-cross threading fastener of Claim 6, wherein the diameter of said protruding diameter member (18) is about 90 percent of the inside diameter of said mating member (36) and about one diameter of said fastener (10) in length. 8. The anti-cross threading fastener of Claim 1, wherein the transitional surface (54) of the at least one transitional thread (24, 34) has a smoothly curved shape. 9. The anti-cross threading fastener of Claim 1, wherein the transitional surface (54) of the at least one transitional thread (24, 34) has an angled crest Hat shape. 10. The anti-cross threading fastener of Claim 1, wherein the transitional surface (54) of the at least one transitional thread (24, 34) has a flat truncated crest shape. 11. The anti-cross threading fastener of Claim 1, wherein the transitional surface (54) of the at least one transitional thread (24, 34) has a curved shape approximated by a plurality of flat and curved surfaces. 12. The anti-cross threading fastener of Claim 1, further comprising a head (12) adapted for the transmission of rotational torque to said fastener (10, 36). 13. The anti-cross threading fastener of Claim 4, wherein the fastener (36) is a nut and the mating member (10) is a bolt. 14. The anti-cross threading fastener of Claim 4, wherein the fastener (36) is a coupling and the mating member (10) is a rod. 15. The anti-cross threading fastener of Claim 4, wherein the fastener (36) is a block of material and the circular opening (32) is counter sunk therein. 16. The anti-cross threading fastener of Claim 5, wherein the fastener (10) is a boll and the mating member (36) is a nut. 17. The anti-cross threading fastener of Claim 1, characterized in that fastener further comprises the mating member (10, 36) and the mating member (10, 36) is at least one mating transitional thread (24, 34) having fourth major and minor diameters, wherein the difference between the first major and minor diameters is greater than the difference between the fourth major and minor diameters. 18. A method of correcting misalignment between the fastener and mating member to prevent cross threading, comprising the steps of: inserting a first end of the fastener (10) into the mating member (36) at a non-collinear angle; characterized by rotating the fastener (10) in relation to the mating member (36), wherein at least one transitional thread (24) proximate the first end of the fastener (10) has a transitional surface from a second minor diameter to a second major diameter of the fastener (10) and is adapted to cam over mating threads (30) of the mating member (36), whereby the longitudinal axis of the fastener (10) and mating member (36) become substantially collinearly aligned. 19. A method of manufacturing the anti-cross threading fastener (10, 36) said method comprising the step of: rolling threads (20, 30) on said fastener with at least one thread forming tap and/or die in a thread forming machine, characterized by said at least one thread forming tap and/or die being adapted to form said plurality of threads (20, 30) and said at least one transitional thread (24, 34).