A draper platform (100) has a knife drive (250) for driving a knife assembly (140) that is supported on and between two adjacent support arms (246) that pivot with respect to each other and with respect to the frame (102, 104, 106) of the draper platform (100) to which the two adjacent support arms (246) are pivotally connected. The two adjacent support arms support a sub-frame (258) of the knife drive, the sub-frame supporting a pivoting drive member (254) on a vertical pivot axis (264).
