the fabric to be sewn is placed the fabric may be for example formed by a portion of a coat and by the revers which has to be sewn upon it in this case the edge of the coat upon which the revers is sewn is placed upon the tongue 22 and the remaining portion is positioned upon the edge of the coat a clamp 42 is provided for clamping the fabric upon the tongue 22 the clamping and opening movements of the clamp 42 are obtained by the operation of a couple of pneumatic cylinders 44 pivoted on a support bar 46 running over the body 20 and borne by the standards 48 and 50 fixed to the same body the stems 52 of the cylinders 44 are connected to the upper portion of the clamp 42 below the tongue 22 pivoted on the vertical wall of the body 20 is a reference element 54 with its outer contour protruding from the edge of the tongue 22 the element is driven by the cylinder 56 arranged as illustated in fig2 and has the task of helping the operator place the fabric in a correct position upon the tongue 22 to this purpose the element 54 is.