Conventional type of DK pipe jack shield machine is completely dismantled into small pieces of part upon reaching to existing pipe or duct. We Daiho developed new type of machine of which major parts (cutter head & thrust driving part) are lifted on the ground without dismantling from tunnel to make it re-usable for next pipe jack tunneling project.

1) A shield machine consists of exterior steel pipe armor, and cutter head(spoke type) and thrust driving part which are accommodated in inner steel pipe.

2) Cutter head (spoke type) is combination of fixed portion which is collected as it is and flexible portion which can be contracted for collection after completion of tunneling work.

3) Since flexible cutter spoke is installed eccentrically to turning axis, long stroke jack can be installed.

4) Collected cutter head and thrust driving part can re-used for different diameter machine. For example, machine ( ø 2,350mm) can be converted into ø 2,580mm machine. We consider that this principle can be applied to machine diameter ranging from 1,300mm to 5,000mm.



5) Cutter diameter contraction can be done by remote control from machine inside. Since parts collection is done through tunnel inside, no dangerous dismantling work in the narrow shaft or duct is required.

6) Re-usablity of major and key parts of machine brings about excellent cost performance compared with conventional non-reusable type. At the same time, smaller shaft and easier works at connection with existing pipe cut cost as well.