six individual chains make up the traveling grate although only two of the chains 26 are shown in fig2 each of the chain links 28 includes cover member 30 that protects the individual links from the heated material being transported on the conveyor grates 20 the tie rods 24 each extend through the chain links 28 and are received within a coaxial spool 32 mounted on the spaced spools 32 are pivotally connected side plates 34 the details of which will be described in greater detail below a plurality of pivotally connected side plates 34 are positioned laterally along the length of the two outermost chains to define a continuous outer edge of the grate conveyor and define a sidewall along the entire length of each outermost chain 26 in this manner the side plates 34 maintain a bed of pellets at a determined depth by preventing the pellets from spilling over the edges of the chains 26 additionally the side plates 34 act to keep the heated air passing through the conveyor within the pre conditioning section 10 referring now to fig3 thereshown is a prior art traveling grate side plate 36 that is positioned along the lateral side of the traveling grate to contain the particles being transferred by the traveling grate as shown in fig3 the side plate 36 includes a front portion 38 and a back portion 40 that are integrally formed as a single monolithic member the front portion 38 includes a series of extended gussets 42 at a thrust button hub 44 the gussets 42 and the thrust button hub 44 extend from a planar front face surface 46 that generally defines.