PROBLEM TO BE SOLVED: To prevent occurrence of such a trouble that grains remaining in a transfer cylinder are held between expanding and contracting screw units and broken or expanding and contracting parts of the screw units are damaged or the like, even when unloading operation is discontinued and the transfer cylinder of an expanding and contracting auger is operated to the contracted side during the unloading operation in which the transfer cylinder thereof is expanded to the longest.SOLUTION: There is provided the expanding and contracting grain unloading auger (4) of a grain tank. In the expanding and contracting grain unloading auger (4) of the grain tank, the transporting cylinder (2) for expansion and contraction is composed so that the position where the total volume of a space (S) which is formed in the transporting cylinder (2), and allows the retention of the grains can be maintained great is the shortest contracted position as compared with the total volume of the grains remaining in the cylinder (2) according to the stop of the expanding and contracting screw (1) when the transporting cylinder (2) for expansion and contraction is operated to the contracted side in the next step in cases where the unloading operation performed by expanding the transporting cylinder (2) for expansion and contraction to the longest is discontinued and driving of the expanding and contracting screw (1) is stopped.COPYRIGHT: (C)2011,JPO&INPIT【課題】伸縮オーガーの移送筒を最長に伸長した排出作業中に、この排出作業を中断して短縮側に操作しても、筒内に残留している穀粒が伸縮螺旋の間に挟まれて破損したり、螺旋の伸縮部分が破損される等の障害が起きないようにする。【解決手段】グレンタンクの伸縮式穀粒排出オーガー(4)において、伸縮用搬送筒(2)を、最長に伸ばして行っていた排出作業を中断して、伸縮螺旋(1)の駆動を停止した場合、伸縮用搬送筒(2)は、次工程で短縮側に操作すると、伸縮螺旋(1)の停止に伴って筒(2)内に残留する穀粒の全容量に対比して、搬送筒(2)内に形成される穀粒の滞留可能な空間(S)の全容積が大きく保てる位置を、最短の短縮位置に構成した。【選択図】 図1
