respect to the conveyor 5 the plate 1 is disposed above and in close proximity with the conveyor 5 and is provided with a leading end 11 that is curved upwardly which serves to facilitate the insertion of the workpieces 7 beneath said plate 1 the folding guide 10 is also provided with a third plate element 3 which extends parallel with plates 1 and 2 and includes an edge 13 that is located between said plates 1 and 2 and which extends at an angle oblique to the direction at which the latter extend the forward end of plate element 3 is depicted by numeral 23 and is curved downwardly to a position of operative association with one of the tapes 6 which is effective in causing the workpieces to enter the guide above said plate element 3 to effect the desired cooperation of the workpiece 7 with the plate element 3 the corner forming the connection between the end 23 and the edge 13 is disposed relative to the movement of the tapes 6 behind a notch 21 formed in the first plate element 1 to facilitate correct sewing and cutting of the folded fabric the trailing end of the edge 13 which is depicted by numeral 33 extends in a direction substantially parallel to the sewing axis and the direction of movement of the tapes 6 the plate element 3 is supported by telescopic members 9 which are connected to the first and second plate elements with the length thereof being adjustable in the direction of insertion of the third plate between said.