1352627 Cutting a web into tiles REDLAND TILES CO 29 Sept 1972 [25 Oct 1971] 49541/71 Heading B5A Apparatus for cutting a continuously moving ribbon 8 of tile forming material, e.g. concrete into discrete tiles 9, 10 of equal length and subsequently trimming the leading edge of each tile comprises a conveyer 11, an extruder 13, a cutting unit 23 and a trimming unit 24, at least one of the units being provided with a knife holder which is reciprocated longitudinally of the ribbon 8 by mechanism including a crank 45 which is rotated once every tile length and which has a throw that results in the forward linear speed of the knife being initially less than, then greater than and finally less than the speed of the ribbon 8 during its cutting action. The throw required may be obtained by arranging that the circumference of the circle described by the crank 45 is between 1 and 3% greater than the length of a tile. The crank 45 may be connected as shown to a knife holder carrying the cutting knife 25 and the trimming knife 26 by a single rod 46 or to a pair of knife holders by a pair of respective rods. The common knife holder may comprise a carriage 21 supported on two crosshead slides 22. The trimming knife unit 24 may be mounted on a sub-frame (35, Fig. 4) so that the distance between the two units may be varied by adjusting a pair of frusto-conical nuts (39, 40) attached to the carriage 21. The knives 25, 26 are actuated by pneumatic cylinders 29, 30. Commencement and length of stroke of the knives may be varied by altering the relative positions of an arm attached to a micro-switch and a cam rotating at the same speed as the crank-shaft 47. The trimming knife may be inclined with respect to the tiles 9, 10. The phase relationship between the knife unit 23 and pallets 12 supporting the ribbon 8 and tiles 9, 10 may be varied by adjusting a slidable frame (70, Fig. 3) acting on a chain (54) of a gear train (51-62, Fig. 3) driving the crank 45 from the drive sprocket wheel 16 of the conveyer 11. A take-off conveyer 19 driven at a higher speed than that of the conveyer 11 is provided.