Multi-wire machine for cutting blocks of stone and wire tensioning device

Multi-wire machine for cutting blocks of natural or artificial stone comprising: rings of diamond wire (2) driven in their cutting motion (M) by a driving drum; a pair of wire-guiding rollers (5), upstream and downstream of the cutting section (7), for determining in the cutting section the correct position of the single wire on the block of stone being processed; a tensioning device of the rings of diamond wire with at least one movable support (18) of a single tensioning member (12) for each ring of diamond wire; and having the tensioning device (9) subdivided into a first tensioning means (10) for large movements, that is to say, intended to put in tension the rings of diamond wire (2) in assembly-maintenance, and a second tensioning means, single for each wire, for the fine tensioning of each diamond wire (2) closed in a ring; both the first and second tensioning means being made oscillating on respective oscillation pins (11, 13, 14) connected to the supporting structure (4); the second tensioning means (12,18) being subdivided into groups (15, 16) in an alternated way, corresponding to the wires they support, even (22) in one group and odd (21) in the other group; finally, said second fine tensioning means are spatially alternated in the groups (15, 16) and those of one group (15, 16) penetrates each other, in the space present between adjacent tensioning means (12, 18) of the other group (15, 16), and between adjacent diamond wires (21, 22) of the other group, in the various tensioning positions which each of the second means (12, 18) assumes in tensioning.