| 摘要 |
<p>An automatically opening and closing closure device adapted for use with a container having a liquid, pasty or foamy filling is described which comprises a head body, a discharge duct in the head body and having an orifice in the outside of the latter, the head body having an opening at a side thereof away from the discharge orifice and being destined for being joined to the container the head body comprising a continuous integral wall portion about the discharge duct and orifice, the wall portion comprising an elastically flexible zone extending from part of the circumference of the orifice toward the opening, the remaining part of the wall portion about the discharge duct and orifice being substantially rigid; and beak means comprising an elastically deflectable spring-loaded arm and being associated with the head body so that the free end of the arm is located on the side of the wall portion containing the flexible wall zone, the spring arm being biassed into engagement with the flexible wall zone near the orifice to hold the latter in sealing engagement with the rigid wall part and closing the orifice, the bias of the deflectable arm being so dimensioned as to yield to a determined excess pressure inside the discharge duct, the elastic wall zone to urge the free end of the beak arm away from the rigid wall part, and thereby to open the orifice while the excess pressure prevails in the duct.</p> |
