Connection of rung to side rail in a ladder

摘要

Ladder construction in which a relatively thick-walled ferrule blank on sleeve is either press fitted upon, or loosely telescopes on, the end portion of a rung and crimped into engagement with the rung. The run end portion with the blank is then projected through a pierced side rail and formed in die members which move axially w.r.t. the blank and shear an outer portion of the blank wall away from the inner portion. The outer portion is formed into flanges which tightly engage the side rail. The blank is pref. al (alloy). Possible to use a ferrule blank having circular surface and non-circular bore whereby a non-circular rung can mounted in a circular opening in the side rail, as the is the easiest configuration to make and a circular form cavity in the die can readily be made by simple machine.