Inflator

An inflator comprising:

• a mouthpiece;
• an air cylinder mechanism including
• a connecting tube that extends axially in a front-rear direction,
• a small-diameter cylinder that extends axially, that sleeves around said connecting tube and that has a front end fixedly connected to said mouthpiece,
• a large-diameter cylinder that extends axially and that sleeves around said small-diameter cylinder
• a unidirectional intake plug that is fixedly mounted to a front end of said large-diameter cylinder and that sleevedly abuts against an outer surrounding surface of said small-diameter cylinder,
• a piston that is fixedly mounted to a rear end of said small-diameter cylinder and that airtightly abuts against an inner surrounding surface of said large-diameter cylinder and an outer surrounding surface of said connecting tube,
• a unidirectional communication plug that fluidly communicates said connecting tube and said small-diameter cylinder, that is fixedly mounted to a front end of said connecting tube and that abuts against an inner surrounding surface of said small-diameter cylinder,
• a first check valve set that is mounted between said connecting tube and said communication plug, and
• a second check valve set that removably seals said front end of said small-diameter cylinder;
• and
• an adjustment mechanism fixedly mounted to a rear end of said large-diameter cylinder and a rear end of said connecting tube, cooperating with said piston to define a first space therebetween, and including
• an adjustment seat that is fixedly mounted between said rear ends of said large-diameter cylinder and said connecting tube, and that has an intake hole and an exhaust hole both of which fluidly communicates said first space to external environment,
• a unidirectional valve that is mounted to said adjustment seat, and that openably seals said intake hole, and
• an exhaust valve set that is mounted to said adjustment seat, and that is operable to openably seal said exhaust hole;
• wherein, said piston and said intake plug cooperatively define a second space therebetween, said communication plug and said piston cooperatively define a third space therebetween that is in fluid communication with said second space, and said communication plug and said second check valve set cooperatively define a fourth space therebetween;
• wherein, while said adjustment mechanism is in a pressure relief state, said exhaust valve set does not seal said exhaust hole, so that said exhaust hole may release air from said first space to the external environment;
• wherein, while said adjustment mechanism is in a sealed state, said exhaust valve set seals said exhaust hole;
• wherein, when said large-diameter cylinder is moved away from said mouthpiece, air from the external environment is sucked into said first space via said unidirectional valve of said adjustment mechanism, air in said second space and said third space is pushed to flow into said fourth space via said communication plug, and said second check valve set is capable of being driven by air pressure of said fourth space to open;
• wherein, when said large-diameter cylinder is moved toward said mouthpiece, the air from the external environment is sucked into said second space via said intake plug and flows into said third space, air in said first space is pushed to flow into said connecting tube and air in said connecting tube is pushed to open said first check valve set while said adjustment mechanism is in the sealed state, and the air in said first space is released via said exhaust hole of said adjustment seat while said adjustment mechanism is in the pressure relief state.