Patent ID: 8079787

Claim:
A hole saw comprising: an arbor having a body portion and a coupling end connected with said body portion and provided with an indentation, a center hole in communication with said indentation, and two opposite first coupling portions at a boundary of said indentation; a saw blade assembly having a saw blade and an adapter connected with said saw blade and provided with a through hole aligned with said center hole of said arbor and a protrusion received in said indentation of said arbor with two opposite second coupling portions; a lid provided with at least one block portion and movably mounted on said body portion of said arbor and movable relative to said arbor between a first position where said second coupling portions of said adapter are blocked by said block portion and coupled to said first coupling portions of said arbor such that said saw blade assembly can't be rotatable relative to said arbor, and a second position where said second coupling portions of said adapter and said block portion are staggered such that said second coupling portions of said adapter are uncoupled from said first coupling portions of said arbor through the rotation of said saw blade assembly; and a drill having one end passing through said through hole of said adapter and inserted in said center hole of said arbor.