Energized restraining gasket for mechanical joints of pipes
View Patent ↗A gasket for converting a standard mechanical joint into a restrained mechanical joint without the need for altered configuration of the bell, spigot, or gland of the joint, and without the need for additional fittings or devices. In the practice of the present invention, a standard mechanical joint's bell and gland configuration can be employed to connect a spigot end of one pipe length to the bell end of another pipe length in a restrained relationship, with the restraint based on forces superior to rubber-to-pipe friction. In more particular discussion of the embodiments taught, the invention includes forming the gasket to fit within the bell in such a manner that a void, or gutter, exists during rest, into which void the gasket compresses, which in turn influences the rotational motion of the segment. In this manner, the configuration of the gasket influences the timing and extent of rotation throughout the process of securing the gland to the bell.
1. A combination of a restraining gasket together with a gland, for use in a stuffing box assembly when connecting a male pipe portion to a female pipe portion, wherein said gland is adapted to be tightenably connected to the female pipe portion, and said restraining gasket comprises:
a) a deformable body having a spigot-facing surface, a radially outward surface, a gland-facing surface in communication with said gland, and a gutter positioned at or radially inward of the radially outward surface and between the a radially outermost area of the locking member and a surface of the gasket that contacts the female pipe portion when the gland is connected to the female pipe portion with the gasket therein between,
b) a locking member disposed at least partially between the gutter and said gland-facing surface, said member having a tooth portion and an embedded body portion, wherein at least a portion of the tooth portion is positioned to engage the male pipe portion.
2. A method of assembling a restrained mechanical joint, comprising the steps of:
a) urging a portion of a gasket into a sealing relationship between a bell and a spigot, and
b) subsequent to step (a), deforming the gasket by tightening a gland to the bell to at least partially collapse a gutter in the gasket;
c) subsequent to beginning step (b), rotating a locking segment into resistive contact between the bell and the spigot.
3. A method of assembly as in claim 2 , wherein the gutter is a void below a radially outer surface of the gasket.
4. A method of assembly as in claim 2 , wherein the gutter is an annular depression in a radially outer surface of the gasket.
5. A gland in combination with a restraining gasket for use in a stuffing box assembly, wherein the gasket comprises a locking segment and is adapted to change its center of pressure as it deforms in response to tightening of the gland to a bell, in such a manner that, during a stage of deformation, a translation of the locking segment occurs in an axial direction, followed in a later stage of deformation by rotation of the locking member, and wherein the locking segment has at least one tooth facing radially inwardly, and is positioned in the gasket such that collapsing of the gutter provides a greater range of motion to a radially outward end of the segment than to the radially inward end of the segment.
6. A gasket as in claim 5 , wherein said locking segment comprises a plurality of teeth disposed radially inwardly and an area between at least two of said teeth is devoid of gasket material.