A joint is connected to a tube and includes a joint body, nut, and ring. The joint body has a tube coupling part and a main body thread part. The nut has a nut thread part and a constricted diameter part. The ring is arranged in a space radially inward of the nut thread part. The ring abuts an abutted part of the nut. The ring has a Young's modulus greater than the tube. The ring has a curved surface part at least at a radially inward portion of the ring axially on the joint body side, the curved surface part bulging radially inward of the ring and axially toward the joint body side. A maximum thickness of the ring in a radial direction is defined as 2r, an axial length of the curved surface part of the ring is defined as h, and =h/r being 0.5 to 1.2.

The present application discloses methods and apparatus for installing fitting components, such as a conduit gripping device, on a conduit to form an assembly. The assembly is joinable with at least one other fitting component to form a fitting. The present application also discloses methods and apparatus for evaluating characteristics of components of a mechanically attached connection. Characteristics that may be evaluated include, but are not limited to, the position of a conduit gripping device on a conduit, an amount of axial compression or stroke of the conduit gripping device, an amount of clamping force applied to the conduit gripping device as the conduit gripping device is compressed, and an amount of torque applied to members that compresses the conduit gripping device.

A fitting for a tube or pipe capable of functioning a high pressures having a first fitting component adapted to receive the conduit end; a conduit gripping device such as a ferrule or ferrules and a second fitting component that can be joined to the first fitting component to cause the conduit gripping device to grip the conduit and seal when assembled. In one aspect of the invention, the first fitting component is constructed from a material that is softer than the material used to construct the second fitting component. An additional aspect of the invention include a retaining portion on the second fitting component that constrains the tube gripping device against pressure. The retaining portion can also be configured to retain the tube gripping device to the second fitting component prior to installation and in a finger-tight condition. A further aspect of the invention includes a first fitting component in which an exterior portion of the component is work hardened radially outward from the tube gripping device. The fitting may optionally be provided with a structure to effect the pull-up by torque functionality.

A fitting for a tube or pipe capable of functioning a high pressures having a first fitting component adapted to receive the conduit end; a conduit gripping device such as a ferrule or ferrules and a second fitting component that can be joined to the first fitting component to cause the conduit gripping device to grip the conduit and seal when assembled. In one aspect of the invention, the first fitting component is constructed from a material that is softer than the material used to construct the second fitting component. An additional aspect of the invention include a retaining portion on the second fitting component that constrains the tube gripping device against pressure. The retaining portion can also be configured to retain the tube gripping device to the second fitting component prior to installation and in a finger-tight condition. A further aspect of the invention includes a first fitting component in which an exterior portion of the component is work hardened radially outward from the tube gripping device. The fitting may optionally be provided with a structure to effect the pull-up by torque functionality.

A conduit fitting of the type having first and second threaded fitting components and at least one conduit gripping device, further includes a stroke limiting member that allows the fitting to be pulled up by applying a predetermined torque. In one embodiment, the stroke limiting member may be a non-integral torque collar. Alternatively, the fitting may also be pulled up by turns or may have an integral torque collar. In still another embodiment, a stroke limiting member is provided that may be used to enable a fitting that is designed to be pulled up by turns to also be pulled up by torque. In other embodiments, the non-integral torque collar may be installed onto one of the fitting components, and then deformed so as to prevent or make it more difficult to remove the torque collar after installation onto the fitting component.

Methods and apparatus for evaluating characteristics of components of a mechanically attached connection are disclosed. Characteristics that may be evaluated include, but are not limited to, the position of a conduit gripping device on a conduit, an amount of axial compression or stroke of the conduit gripping device, and an amount of clamping force applied to the conduit gripping device as the conduit gripping device is axially compressed or stroked.

The present application discloses methods and apparatus for installing fitting components, such as a conduit gripping device, on a conduit to form an assembly. The assembly is joinable with at least one other fitting component to form a fitting. The present application also discloses methods and apparatus for evaluating characteristics of components of a mechanically attached connection. Characteristics that may be evaluated include, but are not limited to, the position of a conduit gripping device on a conduit, an amount of axial compression or stroke of the conduit gripping device, an amount of clamping force applied to the conduit gripping device as the conduit gripping device is compressed, and an amount of torque applied to members that compresses the conduit gripping device.

The present application discloses methods and apparatus for installing fitting components, such as a conduit gripping device, on a conduit to form an assembly. The assembly is joinable with at least one other fitting component to form a fitting. The present application also discloses methods and apparatus for evaluating characteristics of components of a mechanically attached connection. Characteristics that may be evaluated include, but are not limited to, the position of a conduit gripping device on a conduit, an amount of axial compression or stroke of the conduit gripping device, an amount of clamping force applied to the conduit gripping device as the conduit gripping device is compressed, and an amount of torque applied to members that compresses the conduit gripping device.