The main difference between the patent in dispute and the closest prior art is that a convection chamber of the oven according to the invention is formed, on the one hand, by storage elements which are held by means of brackets attached to the outer wall of the combustion chamber and which are in direct planar contact with the outer wall, and, on the other hand, by an outer lining spaced apart from the combustion chamber. This ingenious design allows a simple furnace construction in which a continuous convection air flow is created in the combustion chamber area. If a specialist would like to further develop the well-known furnace “Handöl” under this aspect, he would face the problem that no convection chamber can be found in the area of the combustion chamber of this furnace. In order to use the heat in the area of the combustion chamber for a convection air flow, the known furnace would not only have to be equipped with storage elements in the area of the combustion chamber, but additional convection chambers would have to be formed in this area, which would require a completely new construction of the furnace. Although convection chambers in the area of the combustion chamber are known from other publications, loosely stacked storage bricks are described there in order to avoid stress cracks. In order to exchange a (not coincidentally completely above lying) stone in such a furnace, the stones lying over it would have to be removed first and then stacked up again. On the other hand, each individual stone (each individual storage element) can be exchanged independently for other elements because of its attachment to the outer wall of the fire. In addition, the storage elements must have a minimum thickness (a minimum cross section) for stability because they stand on top of each other without being fastened; such a minimum thickness is irrelevant for the patent in dispute because the plates are fastened (“suspended”) to the outside of the burner. The convection chamber of the patent in dispute thus has a fundamentally different and advantageous structure due to the brackets. The technical solution presented in the patent in dispute is therefore not only new but also inventive compared to the furnaces “Handöl” (Vienna Appeal Court 11.4.2018, 133 R 3/18s).