being fixed to one of the two cross members 69 which also carry the guides 63 in fig1 the rod 65 of the cylinder piston system 67 is completely retracted and the carriage 59 is positioned towards the left in this situation the blade 53 is at the maximum distance from the blade 51 of which the hinge 52 is fixed allowed by sliding the carriage 59 by means of the system 67 by moving the carriage 59 the blade 53 can be made to assume the most suitable position for making the transverse folds at the required distance the carriage 59 can assume either one of only two positions or more than two positions either by means of a system 67 constructed for the purpose or by using a number of cylinder piston systems operating in series and or in parallel in such a manner as to obtain a number of adjustable positions for the transverse fold made by the blade 53 relative to that made by the blade 51 depending on the dimensions of the fabric to be folded the positioning can also be carried out in other ways and with more adjustments including by hand when the carriage 59 is moved its upright 57 causes the projecting plates 520 slidably mounted thereon to also move in the same manner together with the hinges 55 of the two parts 53a and 53b of the blade 53 and the suction tube portions.