Patent ID: 8142393

Claim:
A breast pump comprising: a dome-shaped housing enclosing a pump mechanism operative for reciprocal movement through an inward pump stroke and an outward pump stroke; a breast cup configured to be supported by the housing in engagement with the pump mechanism comprising an interface section configured to form an air-tight seal with an adult human breast received against the interface section; the breast cup and the breast creating a vacuum chamber configured to reduce in volume when compressed during the inward pump stroke and to increase in volume when expanded during the outward pump stroke; the breast cup further comprising an outlet for expelling breast milk expressed from the breast; a one-way valve operative to vent the vacuum chamber to allow the milk to pass through the outlet when the vacuum chamber is compressed during the inward pump stroke to create positive pressure within the vacuum chamber, the one-way valve further operative for sealing the vacuum chamber when the vacuum chamber is expanded during the outward pump stroke to create negative pressure within the vacuum chamber, thereby creating a milking action for causing milk to be expressed from the breast; wherein the pump mechanism comprises a balanced drive system configured to apply force to compress the vacuum chamber during the inward pump stroke and to apply force to expand the vacuum chamber during the outward pump stroke; further comprising a motor and cam gear for translating rotary motion of the motor to linear reciprocating motion of an actuator arm that removably engages with the breast cup to compress the vacuum chamber during the inward pump stroke and to expand the vacuum chamber during the outward pump stroke; and wherein the housing and breast cup are sized and configured to be supported between a breast and a breast cup of a brassier while the breast pump is actively pumping milk from the breast and expelling the milk through the outlet.