Electromagnetic pump with simplified construction

Claim 1

An electromagnetic pump comprising: an electrically insulative coil bobbin wound with an excitation coil and disposed around a sleeve member having a plunger therein; a pair of magnetic cylingers axially inserted from two ends of said coil bobin between an inner surface of said coil bobbin and an outer surface of said sleeve member to constitute a magenetic flux path; a printed circuit board arranged at one side of said coil bobbin and mounted with a transistor and various electronic components; and a pump housing consisting of a cup-like housing body and a lid for closing an opening of said housing body, said pump housing being adapted to enclose said coil bobbin, said pair of magnetic cylinders and said printed circuit board and to hold said pair of magnetic cylinders mounted at said two ends of said sleeve member, said pump housing being made of a magnetic material to form the magnetic flux path together with said pair of magnetic cylinder, said housing body and said lid each having a centrally located outwardly extending integrally formed recessed region for securing the respective ends of said sleeve member and said pair of magnetic cylinders, so that said bobbin, said printed circuit board, said sleeve member and said cylinders can be quickly and conveniently mounted in said housing.