SEALING MATERIAL, PRESSING RING, COUPLING, AND VALVE

摘要

A first projection is formed on the outer periphery of a bulb part, a second projection is formed on the socket rear end of the bulb part, a tapered part is formed with a decreasing diameter from the inner periphery of a heel part to the inner periphery of the second projection, and a third projection is formed on the tapered part. A first dimension B from the first projection to the third projection in an inclination direction opposite to an inclination direction G of the tapered part is smaller than a second dimension C from the first projection to the second projection in a radial direction A.

主权项

1. An annular sealing member made of an elastic material used for a joint in which a spigot formed on an end of a pipe lies in a socket formed on an end of a pipe to be connected to the other pipe,
the sealing member having a heel part fit into a fitting part formed in the socket, and a bulb part disposed between an inner circumference of the socket and an outer circumference of the spigot, the bulb part having first to third projections, the first projection being formed on an outer periphery of the bulb part so as to protrude outward in a radial direction, the second projection being formed on a socket rear end of the bulb part, the bulb part having a tapered part that decreases in diameter from an inner periphery of the heel part to an inner periphery of the second projection, the third projection being formed on the tapered part so as to protrude inward in the radial direction, the third projection being disposed between the heel part and the second projection in a tube axial direction, the third projection having an inside diameter smaller than an outside diameter of the spigot and larger than an inside diameter of the second projection, the sealing member having a first dimension from the first projection to the third projection in an inclination direction opposite to an inclination direction of the tapered part, the first dimension being smaller than a second dimension from an outer periphery of the first projection to the inner periphery of the second projection in the radial direction, wherein if the bulb part is held between the inner circumference of the socket and the outer circumference of the spigot lying in the socket, the second projection increases in diameter and a portion between the first projection and the third projection is compressed in the radial direction so as to keep watertightness between the socket and the spigot.