Kubota Corporation

Toshio Toshima

Takahiro Ishihara

Takashi Yokomizo

Atsushi Maki

Atsuichi Namariyama

Takeshi Hara

A pipe joint with earthquake-proof function is provided. A lock ring engages with an accommodating groove of a socket. A tapered surface converging toward the opening side of the socket is formed on at least one of a portion of the lock ring engaging the accommodating groove and a portion of the accommodating groove engaging the lock ring. When a disengagement prevention force in a pipe axial direction for preventing a spigot from being disengaged from the socket by the engagement is transmitted from an accommodating groove to the lock ring through the tapered surface, a line of action of a component force of the disengagement prevention force in a direction perpendicular to the tapered surface passes the opening side of the socket of a contacting point between a socket bottom end part of the lock ring and the outer periphery of the spigot along the outer surface of the spigot.

Pipe joint with earthquake-proof function

A pipe having a ridge on the spigot and a method of producing such ridge. A ring having a circumferentially disposed split or splits is fitted in an annular groove formed in the outer periphery of the spigot, with the diameter of said ring being adjusted according to the tolerance of the outer diameter of the pipe. A pair of thin-walled portions formed on the circumferentially opposite ends of the ring defining the split are connected together by a connector or connectors operated from the outer peripheral side of the ring.

Pipe having ridge on spigot and method of forming the ridge

A separation preventive pipe joint is provided. A locking ring provided on an inner periphery of a socket is engaged with a projection formed on an outer periphery of an end portion of a spigot to prevent the spigot from being separated from the socket. When the spigot is to move deeper in the socket, a sleeve provided inside the socket abuts the end of the spigot to prevent the movement of the spigot. The movement of the spigot may otherwise be prevented by locating a deeper end face of the socket adjacent to the projection of the spigot. The projection fills up a clearance between the outer periphery of the spigot and the inner periphery of an open end portion of the socket, thereby preventing the spigot and the socket from bending relative to each other. The clearance may otherwise be filled up by means of a ring disposed on the inner periphery of the socket and bolts to be screwed into the socket from the outer periphery thereof to press the ring against the outer periphery of the spigot.

Separation-preventive pipe joint

A separation preventive pipe joint is provided, in which a locking ring is held by an elastic ring with its axis centered in a locking ring receiving groove. An outer peripheral projection is formed on an end portion of the spigot, the outer peripheral projection being engageable with the locking ring from a location deeper than the locking ring. An inner peripheral projection is formed in an inner peripheral portion of the socket which is located deeper than the locking ring receiving groove for backing up the locking ring. A first inner peripheral surface having a larger diameter than the inner peripheral projection is formed in an inner peripheral portion of the socket which is located deeper than the inner peripheral projection. A second inner peripheral surface is formed between the first inner peripheral surface and the inner peripheral projection, the second inner peripheral surface being larger than the inner peripheral projection and smaller than the first inner peripheral surface in diameter.

Growing community of inventors

Amagasaki, Japan

Toshio Toshima