Hole saw mandrel assembly

A quick connect/disconnect mechanism for a rotary bit having a central mounting hole at a proximal end thereof, including:

• a shaft assembly extending axially and having a proximal end adapted to be releasably secured in a rotary tool and a distal end having at least one recess extending therein;
• at least one retainer arm received within said at least one recess in limited rotating fashion;
• said retainer arm including a distal end having a catch adapted to engage the central mounting hole of the bit, and a proximal end;
• a support ring received about said shaft assembly adjacent to said distal end thereof and defining therebetween at least one spring recess, and at least one return spring disposed in said spring recess and impinging on said at least one retainer arm to urge said catch to a first position in which it extends radially inwardly from said distal end of said shaft assembly;
• a release sleeve secured concentrically about said shaft assembly and defining therebetween an interior space, said proximal end of said at least one retainer arm being disposed in said interior space, said at least one retainer arm including a bearing surface projecting radially outwardly therefrom;
• said release sleeve including at least one engagement key extending radially inwardly into said interior space and disposed in proximity to a respective bearing surface of said at least one retainer arm, said release sleeve being secured to said shaft in rotatable fashion to rotate and impinge said at least one engagement key on said bearing surface of said at least one retainer arm to rotate said retainer arm and urge said proximal end of said retainer arm radially outwardly and cause said distal ends of said retainer arms to rotate radially inwardly to a second position and release the rotary bit.