Threaded plastic plug for forced screwing

Abstract

A threaded plastic plug ( 1 ) comprises a single-piece structure, having a longitudinal axis ( 2 ) of symmetry, and comprises a head ( 5 ), a body ( 3 ) with an outer thread ( 6 ) and a cylindrical collar ( 17 b), and a tightening flange ( 4 ) interposed between the head ( 5 ) and the body ( 3 ). The head ( 5 ) has the shape of a tubular solid ( 8 ) projecting from the flange ( 4 ) in a direction parallel with the axis ( 2 ) of the plug ( 1 ), and comprises an inner cavity ( 7 ), accessible from the outside through one end of the solid ( 8 ), the cavity ( 7 ) being laterally surrounded by a non-circular surface ( 22 ) of an annular wall ( 9 ). The wall ( 9 ) of the tubular solid ( 8 ) which surrounds the cavity ( 7 ) having a variable thickness, the greater thickness being located close to the flange ( 4 ) and entirely facing towards the inside of the cavity ( 7 ). [FIG. 1]

1 ) A threaded plastic plug ( 1 ) comprising a single-piece structure having a longitudinal axis ( 2 ) of symmetry, and comprising a head ( 5 ), a body ( 3 ) with an outer thread ( 6 ), and a tightening flange ( 4 ) interposed between the head ( 5 ) and the body ( 3 ); a structure in which the head ( 5 ) has the shape of a tubular solid ( 8 ) projecting from the flange ( 4 ) in a direction parallel with the axis ( 2 ) of the plug ( 1 ), and comprising an inner cavity ( 7 ), accessible from the outside through one end of the solid ( 8 ), the cavity ( 7 ) being laterally surrounded by a non-circular surface ( 22 ) of an annular wall ( 9 ); the wall ( 9 ) of the tubular solid ( 8 ) which surrounds the cavity ( 7 ) having a variable thickness, the greater thickness being located close to the flange ( 4 ), the plug ( 1 ) being characterised in that the body ( 3 ) comprises a smooth cylindrical collar ( 17   b ) preceding the start of the outer thread ( 6 ) of the body ( 3 ) and designed to allow automatic engagement of the thread irrespective of the relative position with which the plug ( 1 ) is presented to the receiving thread.