Abstract: An air powered rocket sled game which includes a body member having at least one and preferably two separate elongated air passageways, the ends of each passageway terminating in close proximity to form a substantial loop pattern. A pair of continuous loop intersecting tracks are provided, one along the upper surface of each passageway. The tracks are grooved and are in communication with the interior of the passageways by a plurality of inclined bores for slidably moving rocket sled projectiles along each track in a single direction. The body member includes a centrifugal blower having separate isolated outlets for each passageway and a valve for each passageway to selectively provide a flow of air along the passageway in a direction opposite to the direction of travel of the projectiles. Also included is a method of manufacturing the inclined bores to provide communication between the grooved tracks and the interior air passageways.

Abstract: An ore classifier adaptable for separating coal from inter-mixed heavy material and which performs a washing operation for the coal. The classifier has an elongated inclined trough, the floor of which is provided with transverse corrugations constructed to resist the movement of particles down the incline. A pair of side panels are provided in the trough to form elongated passageways along the inside sides of the trough, the lower ends of the passageways being closed. The trough is mounted on a frame and is vibrated as water and coal mixed with other ore is introduced into the trough whereby the coal is washed out of the lower end of the trough and the coarse and fine heavies are forced out of the upper end of the trough and passageways, respectively.