Patent ID: 6283141
Filing Date: 2001-09-04
Classification: B25D,F16N,Y10S,Y10T

Abstract:
A liquid metering device for a pneumatic power tool having an air inlet passage and a throttle valve, comprising a closed liquid reservoir with a lower space containing liquid and an upper space containing an air volume, conduit means for communicating pressurized air in alternative flow directions between said inlet passage and said upper space, and a porous filter element within said conduit means and having at least one surface continuously exposed to the liquid in said lower space and an air exposed part in fluid communication with said upper space and said air inlet passage such that liquid absorbed by the at least one surface of the filter is forced into said reservoir by means of in-flowing air when there is a positive relative pressure in the air inlet passage upon start-up of the tool, and liquid absorbed by the filter is pressed out into said air inlet passage by means of out-flowing air when there is a positive relative pressure in the upper space due to shut-down of the tool, a pressure differential being induced at opening and closing of said throttle valve, said filter preventing oil flow in an absence of said pressure differential.