US Patent 9866000 Cable ladder

A cable ladder formed by two side rails and crosspieces, all formed of extruded polymer material. The side rails have a channel receiving a corresponding end of the crosspieces. The channel has a lower rib and an upper rib. A projection of the lower rib or upper rib has openings along a longitudinal direction of the side rail. The ends of the crosspieces go through the opening of the projection and have a recess in which a corresponding portion of the channel is snap-fitted. The lower rib of the side rails is bent over itself along a bending line, such that a final section of the lower rib experiences downward expansion by elastic bending when the end of the crosspiece is introduced.