Pump provided with diaphragms and an eccentric rotation shaft

The present invention relates to a pump provided with diaphragms, and more particularly to a compact pump which is used for a sphygmomanometer or the like. In a pump, a plurality of pump chambers are defined by a plurality of diaphragms. A pivotable member is attached to the diaphragms. A rotator is formed with a first hole having a first diameter, which is arranged eccentrically from a rotation center of the rotator, and a second hole having a second diameter smaller than the first diameter, which is formed in a bottom of the first hole. A shaft member connects the rotator and the pivotable member so as to convert a rotation of the rotator into a pivotal movement of the pivotable member for sequentially deforming each diaphragm to vary a volume of each pressure chamber. One end of the shaft member is fitted into the second hole.