| 摘要 |
A manual air pump includes a cylinder having a first chamber and a head provided to the second end of the cylinder. The head includes an outlet passage communicated with the first chamber for supplying air to an object to be inflated. A first piston rod has a first end with a first piston slidably received in the first chamber. The first piston separates the first chamber into a first chamber section adjacent to the head and a second chamber section distal to the head. The first piston rod defines a second chamber therein. A second piston rod has a first end with a second piston slidably received in the second chamber. The second piston separates the second chamber into a third chamber section adjacent to the first piston and a fourth chamber section distal to the first piston. A handle is secured to the second end of the second piston rod to move therewith. Reciprocating movement of the handle causes high volume/low pressure inflation when the handle is engaged with the first piston rod to allow joint sliding movement of the first piston rod and the second piston rod. Reciprocating movement of the handle causes low volume/high pressure inflation when the handle is disengaged from the first piston rod and the first piston rod is retained in the second end of the first chamber.
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