| 摘要 |
<p>A check valve particularly for molds of plastic molding machines, comprising a valve body (11) that is accommodated in a complementarily shaped seat (12) of a mold (13) for plastic material (14); the valve body (11) is provided with an injection channel (15) inside which a flow control element (16) can float freely between a port (17) for introducing the plastic material (14) and containment means (18) that are suitable to prevent its escape from the valve body (11) and form passage openings (21) for the plastic material (14), the flow control element (16) being adapted to be pushed by the pressure of the plastic material (14) in the injection channel (15). The seat (12) of the valve body (11) has a stroke volume (22) for a reversible translational stroke of the valve body (11) from the inside outward; the valve body (11) has a portion (23) that is suitable to abut against first means (25) for stopping the stroke toward the outside of the mold (13) and against second means (26) for stopping the stroke toward the inside of the mold (13). The translational stroke from the inside outward clears an expansion chamber (24) for the plastic material (14).
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