Torque limiting elastomeric fastener and seal

A reusable self torque limiting elastomeric unthreaded member and threaded member type clamping combination having preselectable screw-induced torque maximum beyond which continued screw-on rotation of said members produces no additional relative axial movement between said members,

• said combination comprising a screw-threaded member and an unthreaded member,
• said unthreaded member comprising a cylindrical screw-thread engaging member of an elastomeric material resiliently deformable without permanent thread formation in said unthreaded member by selectable interference fit engagement between said unthreaded member and the peripheral portions of the thread of said threaded member as screw-on relative rotation of said members produces screw-induced torque forces and axial travel of said members toward each other, said unthreaded elastomeric member having abutment means
• for engaging a part to be clamped and for supplying selectable resistance forces to the relative axial movement of said members during said screw-induced axial travel, said resistance forces and said torque forces combining to provide a limit to said screw-induced axial travel, and
• for achieving preselected radial thread-lock and axial clamping forces at said limit of said screw-induced travel sufficient to maintain said clamping combination of said members in clamping relationship to a member to be clamped, said abutment means comprising a boss dimensioned to effect an abrupt increase in said resistance forces by engagement with a part to be clamped, and flexible sealing means of said elastomeric member extending around the axis of said cylindrical member for effecting sealing engagement around said axis with a part to be clamped prior to the occurrence of said abrupt increase in said resistance forces.