Mini air pump

Abstract

A mini air pump which includes a diaphragm, a bladder base provided with penetrating bladder holes and air inlet channels, a pump body having a valve seat and a pump cover, an air inlet valve, an air outlet valve, a relief valve and a preload member is revealed. The valve seat is stacked over the diaphragm. An exhaust chamber and a spring chamber are constructed by the valve seat and the pump cover. The valve seat has exhaust channels communicating with the bladder cavity. A communicating return channel is constructed by the diaphragm, the bladder base and the valve seat. The return channel is communicating with the air inlet channel but not communicating with the spring chamber. A spring of the preload member applies a preload to the relief valve. Thereby the relief valve acts more accurately and the mini air pump is more stable in use.

What is claimed is: 
     
         1 . A mini air pump comprising:
 a diaphragm which includes a plurality of bladders on one side of the diaphragm and each of the bladders having a bladder cavity with an opening toward the other side of the diaphragm;   a bladder base which includes a plurality of air inlet channels and a plurality of bladder holes penetrating the bladder base in thickness direction while the diaphragm is attached to the bladder base and the bladders are passed through the bladder holes correspondingly;   a pump body which includes a valve seat provided with a plurality of exhaust channels and stacked over the diaphragm, a pump cover stacked on the valve sea, an exhaust chamber and a spring chamber separated from each other and constructed by the valve seat and the pump cover, and a return channel constructed by the valve seat, the diaphragm, and the bladder base and communicating the valve seat, the diaphragm, and the bladder base with one another; the exhaust channels communicating with the bladder cavity while return channel communicating with the air inlet channel but not communicating with the spring chamber;   an air inlet valve disposed in flowing direction of air in the air inlet channel and used for communicating the bladder cavity with the air inlet channel in one-way manner;   an air outlet valve arranged in flowing direction of air in the exhaust channel and used for communicating the exhaust chamber with the bladder cavity in one-way manner;   a relief valve mounted in the exhaust chamber for selectively communicating the return channel with the exhaust chamber; and   a preload member mounted in the spring chamber and having at least one spring which applies a preload to the relief valve.   
     
     
         2 . The mini air pump as claimed in  claim 1 , wherein the air outlet valve and the relief valve are integrally formed on a valve membrane while the relief valve is formed on one side of the valve membrane facing the valve seat; a groove is mounted on the valve seat and the valve membrane is provided with at least one communication hole by which the groove and the exhaust chamber are communicating with each other. 
     
     
         3 . The mini air pump as claimed in  claim 2 , wherein the relief valve is a circular flange which is arranged around an entrance of the return channel and is directly abutting against the valve seat. 
     
     
         4 . The mini air pump as claimed in  claim 2 , wherein the groove includes a circular groove and a plurality of long grooves which are arranged around and radiated from the circular groove while a free end of the long groove is arranged corresponding to the communication hole. 
     
     
         5 . The mini air pump as claimed in  claim 2 , wherein a positioning rod is mounted on the other side of the valve membrane while the preload member further includes a spring seat and the positioning rod is inserted through the spring seat; one end of the spring is abutting against and mounted in a limit slot defined in the spring seat. 
     
     
         6 . The mini air pump as claimed in  claim 5 , wherein a guiding chamber communicating with the spring chamber is formed in the pump cover and the other end of the spring is extended into the guiding chamber while a stopper which applies a pre-tension to the other end of the spring is mounted in the guiding chamber. 
     
     
         7 . The mini air pump as claimed in  claim 1 , wherein the bladder base is further provided with a plurality of sink slots each of which is communicating with the air inlet channel and the return channel correspondingly. 
     
     
         8 . The mini air pump as claimed in  claim 1 , wherein a valve cap is disposed over the pump cover and a buffer chamber is constructed by the pump cover and the valve cap; the buffer chamber is communicating with the exhaust chamber. 
     
     
         9 . The mini air pump as claimed in  claim 8 , wherein a one-way valve is arranged at an air vent of the valve cap or the pump cover. 
     
     
         10 . The mini air pump as claimed in  claim 1 , wherein the air inlet valve is integrally formed on the diaphragm and arranged corresponding to an outlet of the air inlet channel.