The invention relates to agriculture mechanical engineering and can be used for hay-harvesting machines. The inventive device comprises means for forming a layer from treated vegetation and means for forming a bolt from said layer. Said bolt-forming means consists of at least one pair of endless chains which interact with motion specification means and motion trajectory targeting means. An actuating mechanism connected to the opposite sections of the chains by means of a connecting unit is arranged between the chains. Means for joining said connecting unit to a chain elements embodied in the form of two holes for axial elements and one slot for connecting elements of the adjacent chain elements. Said connecting unit can be provided with means for mechanically cleaning the motion defining means. The bolt-forming device makes it possible to reduce mowed vegetation loss and improve the removing of the particles thereof from the elements of a pressing mechanism.
