Stone guard door for harvesters

A harvester having a threshing head pivotally mounted at the front end for raising and lowering movement between a lower operative position and an upper inoperative position, said threshing head comprising a rotatable threshing cylinder, a concave adjacent to and spaced from the threshing cylinder, means for feeding crop along a flow path to the space between the threshing cylinder and the concave, a stone guard door in the flow path, latch means normally retaining the door in a closed position, and operable by a stone above a predetermined size to cause opening of the door and discharge of the stone from the flow path before the stone enters the space between the threshing cylinder and the concave, and door closing means connected between the door and the front end of the harvester and operable by movement of the threshing head to a raised position to effect closing of the door, said door closing means comprises spring means tensioned by initial raising movement of the threshing head, and catch means operable to prevent closing movement of the door during initial raising movement of the head and released by raising movement of the threshing head beyond an initial raised position to cause the door to be shut by energy provided by said tensioned spring means.