The coupling (10) is fabricated from a hardened, hollow cylindrical coupling blank (12).

The second flow pipe includes a cylindrical connector plug (50) adapted for mating with the connector skirt.

The axial outer end part of the fitting cylindrical part (61) is positioned in a resin (22).

A hollow cylindrical connector (3) is introduced into the receiving part (2) in an axial direction.

In the cylindric part of the body (1), right before the borderline with the lower hemispherical bottom (2), there is a cylindric flange port (5).

Each hollow cylindrical connecting member (108A, 108B) is coupled to the end of an arm (106A, 106B), respectively.

In a second embodiment, the bearing hub is simply bolted directly to a cylindrical connector member of the vessel.

An oil supply hole (60) connecting from the inner surface (32b) of a piston (32) to a cylindrical fitting section (32a) is formed.

The coupling (10) is fabricated from a hardened, hollow cylindrical coupling blank (12).

The connector (2) has an inner cylinder member (10) and an outer cylinder member (40).

The reinforcing bar coupler includes a cylindrical sleeve.

The threaded connection comprises at least one substantially cylindrical external thread and a substantially cylindrical internal thread.

The present invention relates to a thread joint of steel for percussive drilling wherein flushing water is used, comprising at least one substantially cylindrical external thread as well as a substantially cylindrical internal thread (12).

The crosslink includes a male connector with a cylindrical cross rod received by a cavity in a female connector.

The second flow pipe includes a cylindrical connector plug (50) adapted for mating with the connector skirt.