228,925. Anderson, N. R. Dec. 8, 1924, [Convention date]. Grates.-A travelling grate is formed by transversely disposed overlapping fuel-supporting elements supported on transverse bars secured to endless driving-chains, air passages being provided between the overlapping elements inclining downwards towards depressions formed in the upper surfaces of the elements, the forward end of each element being to the rear of the bottom of the depression in the next ahead element. Figs. 3 and 4 show one form of the grate in which the grate elements 24<a>, 24<b> are provided with flanges 26<a>, 26<b> having elongated holes 25 for the supporting- bars 27a which engage with driving-chains of the form shown in Figs. 6 and 8 adapted to engage with sprockets 21 on the front drum 5. Transverse rollers 7<a> supported in the side frames of the grate support and agitate grate elements in the upper run between the front and rear drums 5, 13<a>. The air passages 35 between the overlapping grate elements are closed during the passage of the grate elements around the rear drum 13<a> by contact of the flanges of the grate elements with the drum and the overlapping of the grate elements is decreased as shown. An alternative form of rear drum is shown at 13b, Fig. 9, in which the flanges of the grate elements engage with projections 40<a> on the drum, similar projections being provided for the driving-chains. A modified form of grate is shown in Figs. 15 and 16, in which the grate elements 24d are arranged to slide laterally on their supporting bars ber.eath other grate elements 24<e>, 24<c> for the purpose of agitating the fuel and clearing the gas passages 35. The lateral movememt of the elements is effected by staggered rollers 44 supported on vertical axles 43 attached to supports 42 on cross-bars fixed to the side frames of the grate. The side grate elements 24<e> are sealed by bars 46<b> supported on the grate frame 8<a> and by bars or blocks 45 bearing against the bars 46b and directly or through packing 47 against, the side walls of the furnace. In the modification shown in Figs. 10 and 12, the grate elements 24f are provided with projections 60 adapted to engage with slotted supporting-bars 50. The sides of the elements may be provided with grooves and projections to form joints between adjacent elements and so prevent the passage of fuel. The supporting bars 50 are provided at their ends with inclined rollers 54 adapted to engage with inclined bars 55 at the sides of the grate to effect a reciprocating movement of the bars 50 and agitation of the fuel. The grate elements may be provided with ranges having recesses adapted to engage with bulbous flanges on the supporting- bars in such a manner that the elements may pivot about the supporting-bars and hang down on the return run of the grate. The upper run of the grate may be supported by rollers adapted to cause the grate to take a curved or undulating course through the furnace. Fig. 22 shows an alternative method of agitating the fuel bed by providing the supporting bars 64b with projections 74 carrying rollers 73 engaging with an undulating track 70. Various arrangements of projections on the rear drum adapted to engage with the grate elements are also described and shown.