Abstract: The apparatus is adapted to be attached to a self-propelled vehicle and includes a rock raking unit with a toothed rotor and a rock collector bucket connected to one end of the raking unit by double articulated pivot bars to swing between open and closed positions relative to the raking unit. Rocks are raked into the bucket during rotation of the rotor in one direction and, by reversing the rotor when the apparatus is raised to a dump position, the raking unit may be pivoted to an open position relative to the bucket. The apparatus includes an easy-to-fabricate rotor, a power-rotated brush for clearing rocks from the rotor, and a bucket with a perforated bottom.

Abstract: Rear view mirrors for a tractor are mounted on elongated arms which may be adjusted laterally to change the lateral spacing between the mirrors and the tractor, which automatically swing rearwardly or forwardly upon striking an obstruction, and which may be quickly and easily folded to and held in a compact storage position extending longitudinally of the tractor.

Abstract: An audio full range speaker which achieves the propogation of a peaked wavefront from the diaphragm instead of generating a substantially planar wavefront as in the case of the common speaker construction utilizing a diaphragm driven as a piston. The speaker has a substantially planar, thin, flexible film forming the diaphragm mounted within a frame. The diaphragm is driven by a driver which imparts motion to the diaphragm at a small source area, the motion being imparted in a direction normal to the plane of the diaphragm so that ripples radiate from the drive area and travel at the same time across the flexible diaphragm, one behind the other, towards the frame. The rest of the diaphragm is driven by the central moving portion, endowing it with a built-in time delay. Because of the time delay involved in spreading the energy across the diaphragm, the wavefront radiated by the speaker ges a head start at the center and lags towards the edges.

Abstract: Apparatus for varying the nozzle area in the turbine section of a gas turbine engine is disclosed. Nozzle guide vanes extend across the flow path for the working medium gases and are rotatable to alter the area of the nozzle. In one embodiment the rotatable vanes are cantilevered from the outer engine case and are opposed at their radially inner ends by a shroud which is affixed to the inner engine case.