| 主权项 |
1. A power assembly for obtaining duration discharge of a product from a container, the power assembly comprising:
a cylinder cup adapted to be mounted to the container; a piston housing slidably received in the cylinder cup; a rotatable drive screw extending into the piston housing; a piston carried by the piston housing, the piston being in slidingly sealed relationship within the cylinder cup and together with the cylinder cup defining a pump chamber, the piston housing and piston being configured to reciprocate in a first direction to draw the product into the pump chamber when the drive screw is rotated; an actuator sleeve configured to be rotatable relative to the container;
a clutch normally biased into an engaged position wherein the clutch establishes a connection between the actuator sleeve and the drive screw such that rotation of the actuator rotates the drive screw, the clutch being movable from the engaged position to a disengaged position wherein the clutch does not connect the actuator sleeve to the drive screw and thus allows the drive screw to rotate without rotation of the actuator sleeve; an energy storage device configured to store energy upon movement of the piston housing in the first direction, the energy storage device biasing the piston housing and the piston in a second direction that is opposite to the first direction to pressurize the product in the pump chamber; a normally closed valve in fluid communication with the pump chamber that is configured to control a flow of the product from the pump chamber, and; an actuator operatively associated with the valve and the clutch, the actuator being movable to permit opening of the valve to discharge the product from the pump chamber and to move the clutch from the engaged position to the disengaged position. |
