A linear actuator comprises a pair of chains. Each chain has a first link and a second link. The second link of each chain is adjacent to the first link of the chain. A pivotal connection pivotally connects the first and second links. The first link is pivotable about a pivot axis which is non-perpendicular to a longitudinal axis of the first link. A chain connecting member connects the chains at distal ends thereof. A drive mechanism moves the chains between an extended position and a retracted position. At least a portion of each chain is helically wound when the chains are in the retracted position.