Riving knife drive mechanims for a portable circular saw

摘要

A portable circular saw (10) includes motor-and-gear case (20) pivotally supported on a guide shoe (12) by a rear pivot mechanism (26) for rotation about a transverse rear pivot axis, thus allowing for selective adjustment of the blade cutting depth on the opposite side of the shoe. In such an arrangement, the depth of cut setting is increased and decreased when the motor-and-gear case is rotated relative to the shoe in respective first and second directions, while an upper pivotal blade guard (30), which is mounted on the motor-and-gear case for rotation about the spindle (24), rotates in opposite rotational directions in response to respective increases and decreases in the depth of cut setting. Cam and cam follower mechanisms (35, 52, 53, 66, 84, 86) maintain the riving knife (62), the blade (19) and shoe (12) in the same relative angular orientation in a fore-and-aft cutting plane regardless of the depth of cut setting. Such riving knife actuation is accomplished by such mechanisms in response to the rotation of the rear-pivoted motor-and-gear case and the corresponding opposite rotation of the front-pivoted upper gear case.