Patent ID: 11959337
Assignee: MINCON NORDIC OY
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 6:
7. A drilling unit for drilling a hole, the drilling unit comprising a drilling head, said drilling head further comprising:
pulling means for pulling a casing into the hole;
a pilot bit for drilling a center hole;
connecting means; and
a ring bit assembly for reaming the center hole for the casing;
wherein said ring bit assembly is connected to said pilot bit by the connecting means and to said casing by the pulling means,
wherein said ring bit assembly comprises:
a carrier comprising carrier coupling means; and
a plurality of ring bit segments movably attached to said carrier coupling means, the pilot bit being connected to the ring bit assembly by the ring bit segments,

wherein the connecting means comprise:
first locking means located on a circumferential outer surface of the pilot bit; and
second locking means located on a surface of the ring bit segment; and

wherein said first locking means are arranged to receive said second locking means for locking the ring bit assembly and the pilot bit together.