Abstract: A method for dispensing a product from an interior volume of a container to which a power assembly is secured, which includes rotating an actuator sleeve of the power assembly in one direction relative to the container to draw an amount of the product from the interior volume into a pump chamber and to pressurize the pump chamber, and temporarily depressing an actuator of the power assembly to dispense a portion of the product from the pump chamber through a nozzle for a duration of time during which the actuator is temporarily depressed. During the duration when the product is dispensed from the container, the power assembly does not rotate relative to the container, and the power assembly is never rotated in an opposite direction.

Abstract: A power assembly that can obtain duration discharge of product upon a single turn of an actuator sleeve to pressurize product and ready it for dispensing. The assembly includes a piston carried by a piston housing for reciprocation in a cylinder cup having a pump chamber. The actuator sleeve is connected through a clutch disc to a drive screw that is connected to reciprocate the piston housing and piston when the actuator sleeve is rotated. The clutch disc is operative to first disengage the actuator sleeve from the drive screw and then move a stem valve to an open position when an actuator is depressed to dispense product. The power assembly can be used with various energy storage devices such as springs, gases or elastics to exert pressure on product to be dispensed when the actuator is turned.