Screw connection

A method of transferring a negative image formation of a transfer element arranged on an annular face of a ring surface, located on a sealing ring, to an end face of a connecting piece, said method comprising the steps of:

• locating said sealing ring inside a union nut, said union nut having an internal threaded portion;
• inserting a cylindrical tube into said sealing ring;
• tightening said union nut onto said connecting piece a predetermined amount, with the internal threaded portion of said union nut interengaging an external threaded portion of said connecting piece, such that a narrow ring portion at one end of said sealing ring is received in a conical bore of said connecting piece and is radially squeezed thereby, such that an at least one cutting edge located along an interior surface of said sealing ring cuts into a jacket of said tube;
• and
• contacting said annular face of said ring surface, located at a transition from said narrow ring portion of said sealing ring to an enlarged annular reinforcement at an opposite end of said sealing ring, with the end face of said connecting piece such that said transfer element is embossed into the end face of said connecting piece.

A screw joint comprised of:

• a sealing ring having:
• i). a nut side portion at a first axial end with an enlarged annular reinforcement, ii). a narrow ring portion at an opposite axial end, and iii). a ring surface having an annular face with transfer elements arranged thereupon located at a transition from said narrow ring portion to said enlarged annular reinforcement, said annular face having an inclination between 45° and 90° relative to a longitudinal axis of the sealing ring, and at least one cutting edge on an interior surface of the sealing ring;
• a union nut receiving and locating said sealing ring;
• a connecting piece adjoined to said union nut, said connecting piece having a conical bore at one end receiving said narrow ring portion, and an end face located at the one end in contact with the ring surface of said sealing ring, the connecting piece having a negative image formation of said transfer elements embossed on its end face;
• and
• a tube, having an outer jacket, located within said sealing ring, said union nut and said connecting piece cooperating and forcing the at least one cutting edge of the sealing ring into the outer jacket of the tube.

A screw joint comprised of a sealing ring, a connecting piece and a union nut;

• said sealing ring having:
• i). a nut side portion at a first axial end with an enlarged annular reinforcement, ii). a narrow ring portion at an opposite axial end, and iii). a ring surface having an annular face with transfer elements arranged thereupon located at a transition from said narrow ring portion to said enlarged annular reinforcement, said annular face having an inclination between 45° and 90° relative to a longitudinal axis of said sealing ring, and at least one cutting edge on an interior surface of said sealing ring;
• said connecting piece having a conical bore at one end, and an end face located at the one end of the connecting piece, the sealing ring located in the conical bore of the connecting piece, and the union nut threaded onto the connecting piece to capture the sealing ring between the union nut and the connecting piece, the annular reinforcement having a predetermined length such that upon proper tightening of the union nut onto the connecting piece, the ring surface annular face is spaced from the end face of the connecting piece, and
• upon over-tightening of the union nut on the connecting piece, the ring surface annular face contacts said connecting piece end face causing said transfer elements of said ring surface annular face to transfer a negative image formation onto said connecting piece end face.

A screw joint comprised of, in combination:

• a sealing ring having:
• i). a nut side portion located at a first axial end with an enlarged annular reinforcement, ii). a narrow ring portion at an opposite axial end, and iii). a ring surface having an annular face located at a transition from said narrow ring portion to said enlarged annular reinforcement, said annular face having an inclination between 45° and 90° relative to a longitudinal axis of said sealing ring, and at least one cutting edge on an interior surface of said sealing ring;
• a union nut receiving and locating said sealing ring;
• a connecting piece threadably connected to said union nut, said connecting piece having a conical bore at one end receiving the narrow ring portion, and an end face located at the one end in contact with said ring surface of said sealing ring;
• a tube, having an outer jacket, located within said sealing ring, said union nut and said connecting piece, in sealing contact with said at least one cutting edge on said sealing ring interior surface;
• and
• transfer means on said ring surface annular face for transferring an image onto the connecting piece end face when the union nut is tightened to a predetermined amount onto said connecting piece.