Patent ID: 7628101

Claim:
A saw of the type which has a top with an opening in the top through which a saw blade can extend, the height and angular orientation of which can be adjusted, and also configured to be retracted in response to an activation signal being applied, the saw comprising: a plate structure configured to be mounted to the saw below the top; an arm pivotally mounted to the plate structure about a first shaft; a rotatable circular blade having an arbor mounted to the arm at a location spaced from the first shaft, and being configured so that at least a portion of the blade can extend through the top opening and be in a position to cut a work piece when the blade is in its normal operating position; a drive motor with an output shaft operatively connected to power the blade; a firing mechanism having a barrel end portion with a cylindrical bore mounted to the plate structure and an extendable piston positioned in the bore, the extendable piston engaging the arm during its extension and causing the arm to pivot about the first shaft when the firing mechanism is activated by the activation signal being applied, the pivoting of the arm causing the blade to be moved downwardly below the top toward its retracted position; wherein a lower portion of the arm has a curved outer surface at a curvature that is defined by a constant radius about the first shaft that extends from the arbor through an arc of about 90 degrees, the outer surface having a plurality of teeth configured to engage a ratchet member; and a ratchet assembly having a ratchet member biased toward the teeth and being configured to engage the teeth to counter kick back of the arm.