Boring device for lining material in branched portions of lined conduit

A boring device for removing a lining material applied to the inner surface of a pipeline and which covers a branched portion of said pipeline, said boring device comprising:

• a body member supported by a skid member which is disposed to be slidably movable along the inner surface of the pipeline in the longitudinal direction thereof, said body member having a leading end and a trailing end, defining a cylindrical space which opens at one side of the body member,
• an upstanding piston rod, having a leading end and a trailing end, disposed in said cylindrical space and passing through said body member,
• an actuator means for moving said body member forward or backward relative to the skid member and turning said body member about its axis of rotation which extends in parallel with the central axis of the pipeline,
• a borer means mounted on said body member,
• a means for selectively projecting and withdrawing said borer means radially of the pipeline, and relative to the body member, and
• a television camera mounted on the body member so as to be moved and turned as an integral unit with the body member, said television camera being provided with a lens which is directed toward the leading end of said borer member,
• a cylindrical, bottom spindle, having a base end and a second end, fitted outside the piston rod and slidably movable longitudinally of the piston rod, a clearance between the piston rod and the spindle formed with an airtight seal at both the leading end of the piston rod and the base end of the spindle, the arrangement being such that the spindle may be slidably moved relative to the piston rod by a fluid pressure applied to the space between the leading end of the piston rod and both sealed portions,
• a spindle gear supported on the outer periphery of said spindle for free rotation relative to the spindle, said spindle gear having gear teeth formed on the outer periphery thereof which extend along substantially the entire length thereof in the axial direction,
• wherein said borer being mounted on the leading end of the spindle,
• a gear mounted on one side of said body, and
• a hydraulic motor and associated rotating shaft provided for rotatively driving said gear, said rotating shaft having an axis which runs parallel with the rotational axis of said spindle gear, said gear meshing with the gear teeth of said spindle gear.