Patent ID: 6227821
Filing Date: 2001-05-08
Classification: F04B

Abstract:
In a pump comprising at least two separate cylinder housings, each cylinder housing defining a cylinder with an axis, the axes being parallel and spaced apart; a pair of pistons, each piston being reciprocable in a corresponding one of the cylinders so as to reciprocate along the axis of the corresponding cylinder to vary a working volume of the cylinder; a motor positioned between the cylinder housings and driving the pistons so as to reciprocate the pistons; a pair of head members, each head member being fastened to a different one of the cylinder housings; and at least one tube spanning the head members, wherein the tube provides fluid communication between the head members;the improvement wherein:the motor is fixed between the cylinder housings with a fastenerless connection joining the motor to the cylinder housings;a head which is common to both of the cylinder housings is rigid so as to assist securing the housings in a fixed orientation relative to one another; andsaid head is monolithically formed in a single piece of continuous material which includes the head members and the tube.