Apparatus for applying adhesive rider strips to the flattened end edges of tube sections or sacks

An apparatus for applying adhesive rider strips to the flattened end edges of tube sections or sacks, comprising a curved forming plate over the convex outer side of which the rider strip-forming web is guided and which, starting from its rectilinear run-up edge up to the transverse apex line of the curvature, is increasingly curved about its axis lying in the direction of web travel and, behind the apex line up to its run-off edge, is increasingly oppositely curved into the shape of the rider strip framing the edge, characterised in that the groove of the forming plate (5) that embraces the end edges and deforms the web to U shape is disposed in a substantially horizontal plane and the run-up edge is so inclined to the groove that it includes an acute angle with the upper side from its medial plane, and that the hot melt-applying adhesive nozzle (8) is formed by a plate (8.1) which is provided with a slot or bores, is disposed closely above and parallel to the web (6) running up the oblique run-up edge, and is displaceable between its front operative position and a retracted inoperative position.