Fecha de publicación: 08/06/2011 Fuente: WIPO "bee" The chamber (1) has closure elements (10, 20) i.e. sliders, connected with toothed racks (12, 22) and brought into opening and closing positions by a toothed wheel and a rotary handle (46). The closure elements are brought into the opening position against a force of a spring (15) by the handle. A fixing lever (32) is provided with lever arms (31, 35). One of the lever arms cooperates with the racks in the opening position. The other arm has a bearing plate (34) on which a weight (30) i.e. sphere, rests so that the former arm holds the racks against force of the spring in the opening position.