Abstract: A shuttleless loom including a pair of lance bands operative to insert weft threads through a shed of warp threads is constructed with a driving crankshaft which operates to synchronously drive both the lance bands and the reciprocating sley of the loom. A sector gear is mounted upon the sley for reciprocal pivotal movement whereby the lance bands are driven through a gear train meshing with the sector gear. The sector gear is driven through a connecting rod mounted eccentrically upon a drive wheel which is driven by the crankshaft. Because of the eccentric mounting of the connecting rod upon the crankshaft, the reciprocating pivotal motion of the sector gear imparts increased acceleration to the lance bands midway through their travel and a decreased acceleration at the ends of the lance band stroke.