Abstract: A gyroscopic propulsion device includes a rotatable body in which the center of mass of the rotating body is offset away from a first axis to a second axis. The body rotating around the eccentric second axis of the rotating body generates a propulsion force which moves a vehicle to which the device is attached. In preferred embodiments, the body includes a rotating flywheel or a planar system of spokes along which weights oscillate on springs.

Abstract: A power saw having a stationary, tree-supporting platform disc, a rotatable tree cutting disc and drive means for rotating the cutting disc. The saw cutting elements have circular, conical or concave cutting faces with circumferential cutting edges. The cutting elements are removably attached to the saw by means of holders which absorb forces imparted to the cutting elements and transmit the forces to the cutting disc. The holders facilitate rapid replacement of dulled or damaged cutting elements.

Abstract: A firearm employs a gun recoil apparatus wherein the comb portion of the stock is fixed relative to a butt end plate. The stock includes a base portion movable with respect to the comb portion. The base portion has at least one guide bore therein which extends longitudinally with respect to the base portion. The butt end plate includes at least one guide rod affixed thereto which is received and slidable within the guide bore. Means are included for fixedly securing the comb portion of the stock to the guide rod whereby the base portion can, upon firing, move relative to the comb portion and butt end plate. Means are provided for adjusting the height of the comb portion above the base portion.