Patent ID: 7070038

Claim:
An escalator having a twin chain drive system, each chain comprising links consisting of two side plates interconnected by hollow sleeves on which are mounted load bearing rollers, said links being pivotally connected together to form a chain by linking plates and pins that are inserted through holes in the linking plates, and through the bores of the sleeves, characterised in that the hollow sleeves of pairs of selected sleeves spaced at intervals along the length of the chains, each have a bore that is provided with a double tapered surface that converges at a radial plane midway between the side plates of the respective link, and means for carrying a lateral constraint wheel, there being provided an axle comprising a spindle located in the tapered bores of the sleeves of each pair of sleeves of each chain, a spacer assembly located between the sleeves of each pair of sleeves, and means for clamping the chains and said spacer together axially thereby to hold the chains a predetermined distance apart, abutting surfaces of each sleeve of each pair of sleeves and the spacer assembly being of complementary curved shapes that permit relative movement between the spacer assembly and each sleeve of each pair of sleeves whilst maintaining the alignment of the axis of each sleeve of each pair of sleeves orthogonal to the sides of the links of the chain, there being further provided on one end of each axle a rotatable guide wheel that in use engages a guide rail adjacent only one side of one of the chains.