| 摘要 |
A valve operating mechanism for use in a fluid dispenser is described, wherein the fluid dispenser includes a reservoir for a fluid to be delivered, and an fluid outlet for the reservoir, and a piston configured to move through the reservoir, and an actuator for the piston, the valve operating mechanism including a valve, wherein the valve has an upstream side and a downstream side, and characterised in that in at least one point of operation of the valve operating mechanism, the valve is inoperable as a consequence of the pressure difference between the upstream side of the valve and the downstream side of the valve. The valve operating mechanism includes a sleeve 11 that can move relative to a piston shaft 12 with relative rearward biasing of the latter by spring 13. On squeezing grips that are pivotally connected at a lower end (only part of front grip shown) the sleeve is moved forwardly by the rear grip to contact the pivoting lever 16 and hold the valve closed despite pressure fluctuations, but allow release of the lever to allow the inlet valve to open when the grips are released for recharging of the gun on the piston moving rearwardly.
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