Thread protector

Claim 2

In combination, a fitting member and a thread protector; said fitting member having an end portion, said end portion having external threads and each of said threads defining a crest diameter; said thread protector being a generally tubular, polygonal member of resilient material and being positioned axially over the exterior of the threaded end portion of said member to protect the threads thereof from damage, said thread protector having a polygonal cross section substantially uniform along its length, said polygonal cross section having less than six sides and less than six corners defining interior surfaces of the thread protector, each of said sides being normally concave inwardly toward the interior of the thread protector, each of said corners being convex outwardly away from the interior of the thread protector, the radius of curvature of said sides being substantially greater than the radius of curvature of said corners, said sides normally defining an inscribed circle smaller in diameter than the crest diameter of at least some of said threads, said concave sides each being resiliently deformed radially outward from the interior of said thread protector and the length of each of said sides between their associated corners each being increased to increase the diameter of said inscribed circle and to permit the thread protector to be positioned on the end portion of the threaded fitting member, and said concave sides of said thread protector resiliently engaging the crest of at least some of the threads of said fitting member to retain said thread protector on said fitting member.

Claim 3

The combination defined in claim 1, wherein said fitting member includes a predetermined number of wrench flats axially adjacent said threaded end portion, said wrench flats being disposed radially outward of said threads, said polygonal thread protector includes axially facing finger grip means for receiving an axially applied force to axially remove said thread protector from said threaded end portion, and said axially facing finger grip means includes at least one of said corners disposed radially outward of at least one of said flats.

Claim 4

The combination defined in claim 2, wherein the number of said corners of said polygonal thread protector is less than said predetermined number of wrench flats whereby said corners of said polygonal thread protector cannot be aligned with the junctions of said wrench flats.

Claim 5

The combination defined in claim 3, wherein said predetermined number of wrench flats is six and said number of corners is four.

Claim 6

In combination, a fitting member and a thread protector; said fitting member having an end portion, said end portion having external threads, and each of said threads defining a crest diameter; said thread protector being a generally tubular, polygonal member of resilient material and being positioned axially over the exterior of the threaded end portion of said member to protect the threads thereof from damage, said thread protector having a polygonal cross section substantially uniform along its length, said polygonal cross section having four sides and four corners defining interior surfaces of the thread protector, at least some of said sides being normally concave inwardly toward the interior of the thread protector, each of said corners being convex outwardly away from the interior of the thread protector, the radius of curvature of said sides being substantially greater than the radius of curvature of said concave corners, said sides normally defining an inscribed circle smaller in diameter than the crest diameter of at least some of said threads, said concave sides being resiliently deformed radially outward from the interior of said thread protector to a configuration convex outwardly away from the interior of said thread pRotector and the length of said concave sides between their associated corners being increased to increase the diameter of said inscribed circle and to permit the thread protector to be positioned on the end portion of the threaded fitting member, and said concave sides of said thread protector resiliently engaging the crest of at least some of the threads of said fitting member to retain said thread protector on said fitting member.

Claim 7

In combination, a fitting member and a thread protector; said fitting member having an end portion, said end portion having external threads, and each of said threads defining a crest diameter; said thread protector being a generally tubular, polygonal member of resilient material and being positioned axially over the exterior of the threaded end portion of said member to protect the threads thereof from damage, said thread protector having a polygonal cross section substantially uniform along its length, said polygonal cross section having four sides and four corners defining interior surfaces of the thread protector, at least some of said sides being normally concave inwardly toward the interior of the thread protector, each of said corners being convex outwardly away from the interior of the thread protector, the radius of curvature of said sides being substantially greater than the radius of curvature of said concave corners, said sides normally defining an inscribed circle smaller in diameter than the crest diameter of at least some of said threads, said concave sides being resiliently deformed radially outward from the interior of said thread protector to a configuration convex outwardly away from the interior of said thread pRotector and the length of said concave sides between their associated corners being increased to increase the diameter of said inscribed circle and to permit the thread protector to be positioned on the end portion of the threaded fitting member, and said concave sides of said thread protector resiliently engaging the crest of at least some of the threads of said fitting member to retain said thread protector on said fitting member.

Claim 8

The combination defined in claim 5, wherein said external threads are threads which increase in crest diameter as they wind helically from the end of said fitting member, and said resilient deformation of said sides of said thread protector being greater adjacent the threads of larger crest diameter and being lesser adjacent the threads of smaller crest diameter whereby said thread protector conforms to the taper of said threads by expanding in an axially varying manner.