| 摘要 |
A nozzle assembly allows a metered dose of lubricant to be dispensed. It comprises a housing and a piston assembly. The housing defines a piston bore, a stem bore and a spout, all of which axially aligned. It also defines a lubricant passage, an air inlet, and a channel linked to the inlet. Connectable to a source of lubricant, the passage communicates with the stem bore. Connectable to a source of air, the inlet communicates with the stem bore at a position between the passage and spout. The piston assembly has a piston with stem and a spring. The piston lies in the piston bore, its back communicating with the channel. The protrudent end of the stem protrudes into the stem bore and has a groove defined about its circumference. The spring biases the piston assembly into a charge position wherein the groove aligns with the passage. This enables the groove to fill with lubricant. When the source of air allows air to act upon the back of the piston, the piston assembly moves against the spring through a transfer position. In this position, the stem extends further into the stem bore so that the groove lies between the passage and inlet. When fully moved against the spring, the piston assembly reaches a discharge position. In this position, the groove communicates with both the inlet and spout. This enables the lubricant to be discharged from the groove and out the spout along with the air from the inlet.
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