Grease filling apparatus for manual grease gun

A grease filling apparatus for a manual grease gun, the apparatus comprising:

• a cylindrical charging tank configured to store grease supplied through a check valve at a bottom portion thereof;
• a cover comprising an air passage on one side to supply air into the charging tank and a through hole formed at a center thereof and configured to be screwed onto an upper opening portion of the charging tank;
• a cylinder vertically coupled to the cover in a center of a lower surface of the cover, establishing coaxial passage with the through hole of the cover, and extending adjacent to a bottom portion of the charging tank;
• a piston sealingly coupled to an inner surface of the cylinder via a packing member at a bottom portion thereof and configured to detachably connect to a manual grease gun at a top portion thereof, allowing to ascend and descend within the cylinder by moving up and down the manual grease gun;
• a first valve means installed in a lower part of the piston to open a passage in response to the piston descending to suck the grease inside the cylinder into the piston by a pumping force or to close the passage in response to the piston ascending;
• and
• a second valve means installed in the lower part of the cylinder to close the passage in response to the piston descending or open the passage in response to the piston ascending to suck the grease inside the charging tank into the cylinder by the pumping force.