Black Decker Inc.

Stefan Nock

Michael Lester O'Banion

John R Curtsinger

Stephen C Dassoulas

Dean R Edwards

Laura Lindberg, Legal Representative

Steve McClaskey

An improved circular saw blade designed for cutting fiber cement workpieces, which are becoming more and more prevalent on the construction site, includes a PCD/carbide tip () mounted in the rim () of the saw blade () at six, rather than the usual for locations, equally spaced around the blade. The tips are mounted adjacent a relatively large-diameter, semi-circular gullet (), which itself is preceded by a chip and dust minimizer (). The minimizer includes several alternating hills () and valleys () formed in the rim of the saw blade, each hill and valley having the same radius, producing a sinuous array essentially centered on the rim of the blade. It has been discovered that such a dust and chip minimizer reduces the level of dust and chips produced by the blade and clears the same from the kerf generated in the blade-workpiece interface. Ideally, all of the parameters and relief angles for the surfaces on the saw blade tip can be generated by cutting an array of such tips from a large-diameter blank () of PCD fused to a layer of tungsten carbide (), and by mounting the tips onto the blade in such an orientation as to present, preferably, a negative hook or rake angle () to the workpiece.

Saw blade for cutting fiber cement

As system for clamping an rotary tool accessory disc or blade to an output shaft of a rotary tool comprising a cam clamping mechanism and a clutch assembly wherein the cam clamping mechanism comprises: a head element threadably engageable with the output shaft at a location axially outward of the accessory disc; a cam rotatably connected to the head element and rotatable between a clamped and unclamped position, wherein the clamped position the cam exerts a compression force axially inward against the accessory disc or blade; and wherein the clutch assembly comprises: at least one first type of disc located coaxially on and keyed to the output shaft; at least one second type of disc located coaxially on the output shaft and in planar parallel contact with the first type disc; and an inner washer having an internal bore, the inner washer located coaxially on the output shaft, axially outward of and surrounding the first type disc and the second type disc, the inner washer keyed at the internal bore to the second type of disc such that rotation of the second type of disc imparts rotation to the inner washer.

Clutch assembly and clamp mechanism for rotary tool disc

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Baltimore, MD, United States of America

Stefan Nock