Apparatus for processing welded joint parts of pipes
AssigneeKawasaki Jukogyo Kabushiki Kaisha
InventorsToshio Yoshida, Toshio Atsuta
Life of this patent
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Abstract
Tensile residual stress in an annular welded joint part joining the ends of unit pipes is mechanically removed by applying repeated hammering strokes against the inner surface of the pipes over the entire joint part, thereby to cause such part to undergo local plastic deformation. The repeated hammering strokes, which have a peening effect, are applied by several automatically operating hammering devices mounted radially on a rotary head secured to and unitarily moving with a shaft which is driveable in rotation about its axis and in translation in its axial direction.
Claims6
An apparatus for mechanically removing residual tensile stress existing in an annular welded joint part joining the ends of unit pipes, said apparatus comprising:
- a shaft mounted for rotation about an axis thereof;
- a cylindrical head secured coaxially to said shaft and rotatable therewith;
- a plurality of hammering means, each including a respective hammering member, mounted on said cylindrical head in a manner such that said hammer members are movable from said cylindrical head toward the inner surfaces of unit pipes when said cylindrical head is inserted therein;
- motive power means for operating said hammering means to cause said hammering members to repeatedly strike the inner surfaces of the unit pipes;
- driving means, coupled to said shaft, for rotating said shaft and said cylindrical head about said axis and for moving said shaft and said cylindrical head along said axis;
- and
- bearing means in the form of ball-and-socket bearings mounted on a cylindrical outer surface of said cylindrical head for bearing on the inner surfaces of the unit pipes when said cylindrical head is inserted therein.
Dependencies are inferred from the claim text.