Abstract: The invention relates to a tree grille system for covering tree grates. Said system consists of grille sections (1), which are interconnected by couplings (7) to form a self-supporting tree grille. The couplings (7) consist of two fixed coupling parts (8) configured on the grille sections (1) and a coupling part (9) that can be inserted between the other parts and then rotated into a locking position. An arc-shaped rib (18) is configured on the underside of the fixed coupling parts (8), the outer peripheral face (21) of said rib being configured as a ramp-type clamping surface (23). One section of said surface (23) is provided with undulating fluting (24). When the displaceable coupling part (9) is rotated into the locking position, teeth (34) that are formed on said part slide over the fluting (24), causing the displaceable coupling part (9) to be locked by a friction and positive fit in the locking position.

Abstract: The invention relates to a set of components used for producing a load-bearing structure for gratings, comprising pillars and support beams which are removably connected to the pillars via couplings. Flat network-type supporting frames of variable sizes can be formed by using couplings that preferably comprise four connecting elements which are arranged in a cruciform manner for the corresponding connecting elements of the supporting beams. A vertical space can be created between two supporting frames by means of spacers that are disposed on the pillars.

Abstract: A building block for forming a masonry structure comprises at least two stone members disposed one above the other and connected firmly to each other, each of which having a wide section at one end and a narrow section at the opposite end. The sections map into each other via an intermediate section and the stone members are disposed relative to each other in such a manner that, in each case, the wide section of an upwardly disposed stone member seats on the narrow section of the respective stone member lying beneath same and the narrow section of an upwardly disposed stone member seats on the wide section of the stone member lying beneath same.

Abstract: A paving element for the water-permeable reinforcement of surfaces, said paving element comprising a top surface, a bottom surface and a plurality of sides. One or more of the sides have vertical recesses extending from the top surface of the paving element to the bottom surface. The recesses are disposed asymmetrically about the mid points of the sides such that recesses of the adjacent sides of neighboring elements are offset from one another when the neighboring elements are laid in alignment, thereby avoiding alignment of the recesses. Alternatively, an offset of the recesses on neighboring stones is achieved by laying the elements in a displaced or staggered manner.