A conveyor apparatus comprising a base frame and an extendable frame, where the extendable frame is supported within the base frame and a drive assembly. The drive assembly comprises a rotatable drive mechanism which has a plurality of frame engaging portions which are arranged to engage with a plurality of drive engaging portions disposed upon a first one of the base or extendable frames such that when the drive mechanism rotates, the drive assembly is configured to displace the first one of the base or extendable frames with respect to the first between an extended state and a retracted state.