| 摘要 |
<p>The present invention proposes an improved pump that is capable of achieving excellent back suction function with use of characteristics of a depression head, without compromising the ease of depression operations of the head due to the additional function. The pump according to the present invention includes a depression head D5 and an annular piston D4. The depression head D5 is urged upward and also relatively displaceable with respect to the stem D1, and configured such that, when depressed, a lever member D7 of the depression head D5 operates to open a discharge opening 81 by displacing an opening-closing valve member D6 that is urged toward a discharge opening 81, and that a resistive force against the depression of the depression head D5 with respect to the stem is smaller than a resistive force against the depression of the stem itself. The annular piston D4 opens a discharge valve 73, which the annular piston D4 forms in cooperation with a discharge valve seat 40, in an uppermost displacement position and closes the discharge valve 73 in a lowermost displacement position. According to the pump, back suction is caused due to a negative pressure state occurring in the stem D1 until the discharge valve seat 40 is closed by the annular piston D4 during upward displacement of the stem D1.</p> |
