Abstract: In a header having a movably mounted knife and a guard for shielding the moving and rotating components operating the knife, the guard preferably comprising two interconnected parts of which the first part is mounted on the header so as not to move with the knife and the second part is coupled for movement with the knife. In this way, the area shielded by the guard automatically expands and contracts with movement of the knife.

Abstract: A belt drive is described for connecting a stationary pulley to a relatively movable pulley. The belt drive comprises a first guide pulley mounted in a fixed position in relation to the stationary pulley and a second guide pulley mounted for movement with the movable pulley. In the invention, the second guide pulley is mounted in such a manner as to be capable of a limited degree of movement relative to the movable pulley and is spring biased in a direction to maintain the belt in tension.