A floor air pump comprising:
- a base;
- a seat disposed on said base;
- a pressure leaking device disposed in said seat and provided with a receiving compartment in which a pressure leaking slide block is slidably disposed, said pressure leaking slide block provided with a channel capable of being opened or closed by said slide block in motion, said receiving compartment provided with a spring for providing said pressure leaking slide block with a recovery force;
- an outer tube disposed on said base;
- an upper cover disposed on the top end of said outer tube and provided in the center thereof with a through hole;
- an outer cylinder disposed in said outer tube such that said outer cylinder is connected at one end thereof with said seat, and other end thereof with a lower end of said upper cover;
- an inner cylinder received at one end thereof in said outer cylinder such that other end of said inner cylinder is exposed via said through hole of said upper cover and is provided with a handle unabling a user to pull said inner cylinder to move along the longitudinal direction of said outer cylinder;
- an outer cylinder piston disposed in the bottom end of said inner cylinder and fitted into said outer cylinder, said outer cylinder piston and said seat forming therebetween a first pressure space, said outer cylinder piston provided in the outer periphery with a one-way air admission valve enabling air to enter said first pressure space in a one-way manner, said outer cylinder piston provided in a center thereof with a through hole whereby said through hole is provided in the inner wall thereof with at least one leakproof ring;
- an inner cylinder piston disposed in said inner cylinder such that said inner cylinder piston and said handle form therebetween a second pressure space, said inner cylinder piston provided in the outer periphery thereof with a one-way air admission valve enabling air to enter said second pressure space in a one-way manner, said inner cylinder piston provided in a center thereof with a guide hole;
- a check valve disposed in said guide hole of said inner cylinder piston to enable air to enter said guide hole in a one-way manner from said second pressure space;
- a guide tube connected between said seat and said guide hole of said inner cylinder piston such that said guide tube is put through said through hole of said outer cylinder piston;
- an air leaking channel disposed in said seat to connect said receiving compartment of said pressure leaking device with said first pressure space of said outer cylinder;
- a first passageway disposed in said seat to connect said guide tube with said receiving compartment of said pressure leaking device;
- a second passageway disposed in said seat to connect said first passageway with said outer cylinder outer space;
- an output channel disposed in said seat to connect said first pressure space of said outer cylinder with said second passageway;
- a check valve disposed in said output channel to enable air to flow outward in a one-way manner from said first pressure space;
- a pressure gauge disposed in the outer side of said outer tube such that said pressure gauge is in communication with the interior of said outer tube;
- and
- an air discharging tube in communication with said pressure gauge and the air valve of an inflatable object being inflated.