Compression set limiting gravity conveyor

Abstract

An undriven gravity roller conveyor is disclosed in which a first plurality of idler conveyor rollers having a rigid outer annular wheel surface and an annular tire of an elastomeric material with an inner annular bearing surface of complementary shape, mounted on each rigid outer annular wheel surface, are arranged in successive rows for conveying loads of cargo. The elastomeric tires, as mounted on the wheel surfaces, have substantially equal radial thicknesses providing outer annular bearing surfaces with a first radial dimension and a first circumferential surface area, and are made of a material having an elastic limit by which each of the tires acquires a permanent deformation known as compression set when radially depressed. Support structure having rigid outer annular bearing surfaces concentric with and rotatable about corresponding axes of rotation with the elastomeric tires, have rigid outer annular bearing surfaces characterized by a second and lesser radial dimension and a second circumferential surface area not less than one-half of the first circumferential surface area, receive and directly engage concurrently with one or more of the tires disposed about the corresponding axes a load being simultaneously supported and conveyed by one or more of the tires before the elastomeric material is subjected to an amount of radial deformation which will result in an undesirable amount of compression set.