Abstract: Rigid cover panels of the cover for grain storage tubes on combines, harvesting machine, are preferably fabricated of double-wall plastic to limit weight of the cover while providing desired strength and rigidity. The rigid cover panels can be pivoted about top edges of an underlying grain tank whereby the cover panels function as a height extension of the underlying tank, thus to increase the grain-carrying capacity of the tank. Flexible transition panels are preferably mounted to the rigid cover panels to bridge spaces between edge regions of the rigid cover panels when the rigid cover panels are raised to their upright, tank-extending orientations. A preferably single underlying actuator in the tank, in combination with mechanical linkages, can simultaneously raise all the rigid cover panels, all the flexible transition panels, and the discharge end of a clean grain elevator which discharges grain into the tank.

Abstract: A grain tank extension having side panels that are rotatably mounted to the grain tank to lower the extension by pivoting the side panels into the tank for storage. Corner panels are provided between adjacent side panels and are integrally formed with the stud at each end for coupling the corner panels to the side panels. Flanges extend beyond the ends of the side panels and overlap abutting ends of adjacent comer panels. The flanges each have an aperture that receives the stud from the adjacent corner panel. The stud is held therein by a retaining pin to avoid the need for hand tools to lower the extension for storage. The corner panels are molded of plastic as a single piece plastic body with the studs integrally formed therein.