Key unit for construction has an insertion wheel and a key body which is connected to the insertion end

摘要

The key unit has an insertion wheel (20) and a key body (10) which is connected to the insertion end. In the middle of the insertion wheel is a many cornered insert (23) which has many block recesses (23) and evenly distributed clamping blocks and supporting blocks. Each clamping block has at least two teeth cutting angles between 57o and 61o.