The invention relates to a plug connection between two tubular workpieces (1, 2) which are made of concrete and each of which has an inner liner (5) made of plastic, one of which forms a tip end (3) and the other a socket end (4) receiving the tip end (3), wherein the inner liners (5) have circumferential sealing flanges (12) which cover the end face (13) of the tip end (3) or the socket face (14) and wherein a joint seal (16) is provided between the sealing flanges (12). In order to provide advantageous structural conditions, it is proposed that the inner liners (5) are provided with a circumferential elastomer angled profiled section (8, 9) at the end face, which receives the circumferential edge of the inner liner (5) in an end-face profiled groove (11) of its axially parallel limb (10) and whose limb at a right angle to the axis forms the sealing flange (12).

The invention relates to a plug connection between two tubular workpieces (1, 2) which are made of concrete and each of which has an inner liner (5) made of plastic, one of which forms a tip end (3) and the other a socket end (4) receiving the tip end (3), wherein the inner liners (5) have circumferential sealing flanges (12) which cover the end face (13) of the tip end (3) or the socket face (14) and wherein a joint seal (16) is provided between the sealing flanges (12). In order to provide advantageous structural conditions, it is proposed that the inner liners (5) are provided with a circumferential elastomer angled profiled section (8, 9) at the end face, which receives the circumferential edge of the inner liner (5) in an end-face profiled groove (11) of its axially parallel limb (10) and whose limb at a right angle to the axis forms the sealing flange (12).

A mechanical joint restraint includes: a gasket defining an inner surface and an outer surface, the inner surface defining a bore, the bore defining an axis therethrough, the gasket defining a first gasket end and a second gasket end; a gland defining a bore defining an axis and positioned axially outward from the gasket with respect to the first gasket end with the mechanical joint restraint in an assembled condition, the axis of the gland aligned collinearly with the axis of the gasket; a gripping ring positioned between the gasket and the gland, the gripping ring being a split ring defining a pair of circumferential ends and a gap therebetween; and a bridge engaging each of the pair of circumferential ends of the gripping ring and extending in a circumferential direction of the gripping ring across the gap therebetween with the mechanical joint restraint in the assembled condition.

A mechanical joint restraint includes: a gasket defining an inner surface and an outer surface, the inner surface defining a bore, the bore defining an axis therethrough, the gasket defining a first gasket end and a second gasket end; a gland defining a bore defining an axis and positioned axially outward from the gasket with respect to the first gasket end with the mechanical joint restraint in an assembled condition, the axis of the gland aligned collinearly with the axis of the gasket; a gripping ring positioned between the gasket and the gland, the gripping ring being a split ring defining a pair of circumferential ends and a gap therebetween; and a bridge engaging each of the pair of circumferential ends of the gripping ring and extending in a circumferential direction of the gripping ring across the gap therebetween with the mechanical joint restraint in the assembled condition.

Provided is a pipe detachment preventing device, for a union nut pipe fitting, which can omit an inner core and which can prevent detachment of a pipe from a pipe fitting even when a large pulling force which stretches the pipe acts. Connection holding means (7) includes an inclination mechanism (8) configured to incline a retaining ring (4A) in a pipe axis direction (X) with respect to a reference plane (P) orthogonal to a central axis (C) of a retaining ring body (40), such that one of a circumferential center portion (40y) and a circumferential end portion (40x) of a retaining ring body (40A) is caused to be closer to a fitting body (2) and the other is moved away from the fitting body (2), when first protruding portions (41) and first facing portions (55) come into contact with each other and a pipe pulling force which stretches a joint pipe (100) is applied to the joint pipe (100).

Provided is a pipe detachment preventing device, for a union nut pipe fitting, which can omit an inner core and which can prevent detachment of a pipe from a pipe fitting even when a large pulling force which stretches the pipe acts. Connection holding means (7) includes an inclination mechanism (8) configured to incline a retaining ring (4A) in a pipe axis direction (X) with respect to a reference plane (P) orthogonal to a central axis (C) of a retaining ring body (40), such that one of a circumferential center portion (40y) and a circumferential end portion (40x) of a retaining ring body (40A) is caused to be closer to a fitting body (2) and the other is moved away from the fitting body (2), when first protruding portions (41) and first facing portions (55) come into contact with each other and a pipe pulling force which stretches a joint pipe (100) is applied to the joint pipe (100).

A method of coupling a pipe length to a piping element includes sliding a gland over an end of the pipe length, the gland including a joint restraint assembly, the pipe length defining an outer pipe surface; inserting the end of the pipe length into a socket defined by the piping element; fastening the gland to the piping element; and activating the joint restraint assembly to prevent removal of the pipe length from the socket by rotating a gripper in an engagement direction of the joint restraint assembly; and engaging the gripper with the outer pipe surface in an initial engagement position.

A method of coupling a pipe length to a piping element includes sliding a gland over an end of the pipe length, the gland including a joint restraint assembly, the pipe length defining an outer pipe surface; inserting the end of the pipe length into a socket defined by the piping element; fastening the gland to the piping element; and activating the joint restraint assembly to prevent removal of the pipe length from the socket by rotating a gripper in an engagement direction of the joint restraint assembly; and engaging the gripper with the outer pipe surface in an initial engagement position.

A spreader structure for a ring seal for sealing an annular gap, includes a radially inner first component with an inner contact surface, a radially outer second component with an outer contact surface, and a first spreading mechanism formed between these two components that includes a first spreading bevel formed on one of the two components, and a first spreading element formed on the other component, that can be moved along the first spreading bevel. The two components can be displaced in relation to one another, from an assembly state to a spreading state, by means of which the first spreading element is moved from a first section of the first spreading bevel to a second section of the spreading bevel, enlarging a radial spacing between the inner contact surface and the outer contact surface. The spreader structure has a second spreading mechanism.

A pipe joint includes: a sealing member, having an annular shape, which is provided between the outer circumferential surface of a spigot and an inner circumferential surface of a socket; a pushing ring to push the sealing member into the socket, the pushing ring being fitted onto the spigot; and a separation preventive member configured to engage with the spigot protrusion part in a pipe-axial direction to prevent a separation of the spigot from the socket. The separation preventive member is provided between an inner circumferential surface of the pushing ring and the outer circumferential surface of the spigot. The sealing member is provided along an outer circumferential surface of the spigot protrusion part and includes a compression part. The compression part is compressed in a pipe-radial and is located, in the socket, upstream of the spigot protrusion part in an insertion direction in which the spigot is inserted.