Patent ID: 8156959

Claim:
A branching unit for boring without stopping passage of fluid, which is suitable for forming an opening at a pipe wall by boring a part of the pipe wall of an existing pipe using a drill machine having a hole saw to connect a branch pipe to the existing pipe, comprising: a sealing case including a first separate casing and a second separate casing separated in a circumferential direction of the existing pipe as well as surrounding a part of the existing pipe, and a branch pipe portion formed integrally with the first separate casing as well as projecting and branching off in a radial direction of the existing pipe; a valve body having an arc shape in cross section which opens and closes a branch hole of the branch pipe portion by rotating along the circumferential direction of the existing pipe between an inner circumferential surface of the sealing case and an outer circumferential surface of the existing pipe; a valve seat formed at the inner circumferential surface in the first separate casing, the valve body touching the valve seat in a valve closing state; and a rotation mechanism for rotating the valve body, wherein the rotation mechanism comprises an operation gear rotationally operated from an outside of the sealing case and a driven gear meshed with the operation gear, the driven gear is rotated by the rotation of the operation gear in the circumferential direction, the valve body being reciprocated to open and close the branch hole, and the operation gear is provided at the second separate casing including no branch pipe portion.