Patent ID: 8197237

Claim:
A metering pump, comprising a pump sleeve comprising a liquid-inlet hole and a liquid-outlet hole; a pump body comprising a cavity and a diversion outlet; a plunger; and a drive device, comprising a housing; a rod; a limiting device; a sliding block; a rotating block; a pair of springs; a pair of first grooves; and a second groove; wherein said pump body is movably disposed in said pump sleeve; said plunger is disposed in said cavity of said pump body; said diversion outlet is disposed on a side wall of said pump body and connected to said cavity; said liquid-inlet hole and said liquid-outlet hole are opposite to said diversion outlet; said diversion outlet is alternatively aligned with said liquid-inlet hole and said liquid-outlet hole; said housing is fixedly connected to said pump sleeve; said rod is fixed to said pump body; said limiting device operates to limit travel distance of said pump body; said sliding block is movably disposed in said housing; said plunger is fixedly connected to said sliding block; said rod passes through said sliding block; an axis is disposed on said sliding block; said rotating block is disposed on said axis; said springs are disposed on both sides of said rotating block; the top of said spring is contacted with one side of said rotating block; said first grooves are disposed on one side of said rod opposite to said housing; said second groove is disposed on inner side of said housing opposite to; a middle part of said second groove is located radially outward from the centerline of the plunger; one end of said rotating block slides in said second groove; and the other end of said rotating block slides in and between said first grooves.