with reference to fig1 to 9 , an air pump for an air mattress has a housing ( 10 ), a chamber ( 101 ), a first air vent ( 102 ), a second air vent ( 103 ), a mounting rack ( 30 ) and a motor ( 40 ), an air valve ( 20 ). the chamber ( 101 ) is defined inside the housing ( 10 ). the first air vent ( 102 ) is mounted on a top of the housing ( 10 ), communicates with the chamber ( 101 ), and is exposed beyond the air mattress in which the air pump is mounted . the second air vent ( 103 ) is mounted on a bottom of the housing ( 10 ) opposite to the top of the housing ( 10 ), and communicates with the chamber ( 101 ) and an inner space of the air mattress . the first air vent ( 102 ) and the second air vent ( 103 ) may be arranged to directly align to each other . the air valve ( 20 ) is mounted at the second air vent ( 103 ) to block or open the second air vent ( 103 ). the mounting rack ( 30 ) and the motor ( 40 ) are mounted inside the chamber ( 101 ) and located between the first air vent ( 102 ) and the second air vent ( 103 ). the mounting rack ( 30 ) has a grip ( 31 ), a first air compartment ( 32 ) and a second air compartment ( 33 ), a first opening ( 301 ), a second opening ( 302 ), an air outlet ( 34 ), an air inlet ( 35 ), an undulant baffle ( 36 ) and a blocking plate ( 11 ). the grip ( 31 ) is mounted on a top surface of the mounting rack ( 30 ) and extended therefrom . the first air compartment ( 32 ) communicates with the second air compartment ( 33 ) through the first opening ( 301 ) formed through a first partition ( 37 ) between the first air compartment ( 32 ) and the second air compartment ( 33 ), and both air compartments ( 32 , 33 ) are adjoined at one end of the mounting rack ( 30 ). the second air compartment ( 33 ) communicates with the first air vent ( 102 ) through the second opening ( 302 ) formed through a second partition ( 38 ) of the second air compartment ( 33 ). the air outlet ( 34 ) is formed through a bottom side of the first air compartment ( 32 ) to align to the second air vent ( 103 ). the air inlet ( 35 ) is formed through a bottom side of the second air compartment ( 33 ) to align to the second air vent ( 103 ). the air inlet ( 35 ) and the air outlet ( 34 ) are juxtaposed on a circle centered at a pivot axis of a pivot shaft of the mounting rack ( 30 ). the undulant baffle ( 36 ) is formed on the mounting rack ( 30 ) to constantly contact with the air valve ( 20 ). the undulant baffle is preferred to take a form of having two wave crests and one wave trough . the blocking plate ( 11 ) is pivotally mounted on the pivot shaft of the mounting rack ( 30 ). when the mounting rack ( 30 ) is rotated and the air inlet ( 35 ) communicates with the second air vent ( 103 ), the blocking plate ( 11 ) is covered on the second opening ( 302 ) to prevent air from leaking from the second opening . when the mounting rack ( 30 ) is rotated and the air outlet ( 34 ) communicates with the second air vent ( 103 ), the second opening is not covered by the blocking plate ( 11 ), thereby facilitating air flowing into the second air compartment ( 33 ) through the second opening ( 302 ) and forming a gust of intake air flow . the motor ( 40 ) is fixedly mounted at the other end of mounting rack ( 30 ), is located inside the mounting rack ( 30 ), and is synchronously rotated with the mounting rack ( 30 ) when the mounting rack ( 30 ) is rotated . the motor ( 40 ) has an impeller ( 41 ) mounted on a spindle of the motor ( 40 ) and located inside the first air compartment ( 32 ). the air valve ( 20 ) has a yoke ( 21 ), a spring ( 22 ) and a rubber plate ( 23 ). the yoke ( 21 ) has a seat ring ( 211 ) and a stem ( 212 ). the seat ring ( 211 ) has a plurality of arms radially connected with a center and a rim thereof . the stem ( 212 ) is perpendicularly extended from the center of the seat ring ( 211 ). the rubber plate ( 23 ) is fixedly mounted to the seat ring ( 211 ) and accompanies with the seat ring ( 211 ) to hermetically seal the second air vent ( 103 ). a tail end of the stem ( 212 ) penetrates through a positioning hole defined at the second air vent ( 103 ) to prop up a bottom surface ( 414 ) of the sloping partition ( 413 ). the spring ( 22 ) is sleeved around the stem ( 212 ). one end of the spring ( 22 ) is urged against the tail end of the stem ( 212 ) and the other end is urged against an inner surface of the housing ( 10 ) so that the yoke ( 21 ) and the rubber plate ( 23 ) as a whole can elastically seal or open the second air vent ( 103 ). with further reference to fig3 to 7 , operation of the present invention is described as follows . the air pump of the present invention has three types of operating modes , namely , inflation , pressure hold - up and deflation . during the inflation mode , air outside the air mattress is promptly pumped into an inner chamber of the air mattress to inflate the air mattress until it is ready for use . upon inflating , the grip ( 31 ) on the mounting rack ( 30 ) is shifted to rotate the mounting rack ( 30 ) with respect to the axis of the pivot shaft of the mounting rack ( 30 ) so as to let the air outlet ( 34 ) directly communicate with the second air vent ( 103 ). then , the motor ( 31 ) drives the impeller ( 32 ) to rotate with a high speed and generates a gust of intake air flow , and the air valve ( 20 ) is either pushed by the gust of intake air flow or propped up by the undulant baffle ( 36 ) to open the second air vent ( 103 ). air outside the air mattress sequentially flows through the first air vent ( 102 ), the second opening ( 302 ), the second air compartment ( 33 ), the first opening ( 301 ), the first air compartment ( 32 ), the air outlet ( 34 ) and the second air vent ( 103 ) to the inner chamber as marked by arrowheads in fig3 and 4 , to fulfill the function of inflation . during the pressure hold - up mode , the air mattress is fully inflated and the motor ( 40 ) is switched off by shifting the grip ( 31 ) as shown in fig5 . at the time , since the air pressure in the inner chamber of the air mattress is far higher than the atmospheric pressure outside the air mattress , the air valve ( 20 ) tightly seals the second air vent ( 103 ) due to the pressure difference effect , achieving the pressure holding function . during the deflation mode , air inside the inner chamber of the air mattress is evacuated . when the air mattress is no longer in use and needs to be packed up and deflated , the grip ( 31 ) on the mounting rack ( 30 ) is shifted to rotate the mounting rack ( 30 ) with respect to the pivot axis of the mounting rack ( 30 ) so as to let the air inlet ( 35 ) communicate with the second air vent ( 103 ). meanwhile , the air valve is propped up by the undulant baffle ( 36 ) to open the second air vent ( 103 ), and the motor ( 31 ) drives the impeller ( 32 ) to rotate with a high speed and generates a gust of exhaust air flow . after sequentially flowing through the second air vent ( 103 ), the air inlet ( 35 ), the second air compartment ( 33 ), the first opening ( 301 ), the first air compartment ( 32 ), the air outlet ( 34 ) and the first air vent ( 102 ) ( as marked by arrowheads in fig6 and 7 ), air inside the air mattress is evacuated to fulfill the function of deflation . besides , air flowing along the air path inside the air pump also carries away the heat generated by the motor ( 40 ). in sum , the present invention is characterized in that the first and second air compartments are alternately aligned with communicate with the second air vent by rotating the mounting rack , and the air valve is propped up by the undulant baffle on the mounting rack , so as to switch the operating modes of the air pump . in contrast to conventional air pumps using the rod of the solenoid valve to simultaneously drive the slider and the air valve , the arrangement of the first air vent and the second air vent in the present invention is more flexible . given the flexible arrangement , the first air vent and the second air vent can be respectively mounted on a top surface and a bottom surface of the housing . as such , the air path inside the air pump is shortened to result in a direct and fast inflation and deflation of the air mattress . even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description , together with details of the structure and function of the invention , the disclosure is illustrative only . changes may be made in detail , especially in matters of shape , size , and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed .
an air pump manually rotated to inflate and deflate an air mattress has a housing , a first and a second air vents mounted on the housing , an air valve selectively actuated to block or open the second air vent , and a mounting rack in the housing . the mounting rack is rotated so that a first or a second air compartment in the mounting rack is aligned with the second air vent , and the air valve is propped up by an undulant baffle on the mounting rack to switch to one of inflation , deflation and pressure hold - up modes . given the structure of the air pump , the first and second air vents are flexibly arranged and can be respectively mounted on a top and a bottom of the housing and directly aligned with mutually . therefore , the air path is shortened to make the inflation and deflation faster and more efficient .