there is shown on fig1 and 2 a portion of a grate plate group having grate plate supports 1 and 2 respectively each of which supports a row of grate plates which are alternatingly fixed plates 4 and movable plates 5 and extend transversely to the direction of the grate the grate plate support 1 hereinafter is identified as the fixed support the grate plate support 2 as the reciprocating support the reciprocating support is driven reciprocably back and forth in the direction of arrow 3 the fixed and the movable grate plate supports are capable of supporting grate plates of different shapes and are provided for a grate with a horizontal extension and horizontal direction of movement of the movable plates the invention however is applicable also to inclined or ascending grates and independently of the prevailing shape of the grate plate the grate connector devices cooperating on the grate plate supports and the grate plates for their mutual connections are the same for all types of grate plates and are hereinafter described by reference to the plate with a corresponding grate plate support shown on fig1 and 2 in the center and on fig3 and 4 the grate plate support has two parallel flanges 6 and 7 which are rigidly connected by walls 8 extending perpendicularly to the planes of the flanges wherever a grate plate is to be supported by the grate plate supports flanges 6 and 7 are provided on the.