Twist Top Hole Saw

The locking device consists of a metal plate with diametrically opposed increasing radii along 180 degrees swing on each side. This plate rests on the surface of the aforementioned ring and rotates into place between a set of arched metal strips placed on that ring. For the purpose of this claim the strips are designed so that the lower portion (plate contacting surface) is slightly indented. This creates an overhang that will hold the plate, when in the locked position, against the ring. The strips are located on top of and on opposite sides of the ring. The strips are arched and set in such a manner that their total plate connecting surfaces will press, with equal force, against the two diametrically opposed sections of the plate's edge, as that plate is rotated into the locked position. Due to the off center design of the plate and strips, the plate is held in place by torque, and the overhang feature of the strips, while the saw is cutting. At other times, the plate is prevented from rotating out of position by friction provided by rubber washers attached to the top of the plate that press against the upper (overhanging) part of the strips. The limited projection of the overhang is such that it will allow the plate to clear its confines when rotated to the unlocked position. The locking torque translates into the driving force for the hole saw to perform its cutting action.