Patent ID: 8757914

Claim:
An apparatus for dispensing a fluid, the fluid dispensing apparatus comprising: a housing defining an open interior; a resilient liner adapted to hold the fluid, the liner configured to be at least partially disposed in the interior of the housing; an applicator assembly for dispensing the fluid on the user's skin, the applicator assembly mounted on the housing, the applicator assembly including an actuator movable relative to the housing in a first direction and a second direction, and a fluid delivery element which is held in contact against skin of a user for applying the fluid onto the skin, the fluid delivery element supported on the actuator to be movable together with the actuator by varying contact pressure with the skin; and a pump assembly at least partially disposed in the housing, the pump assembly comprising a pump chamber having an inner surface defining an interior cavity for accommodating fluid, an end of the pump chamber configured to be in fluid communication with the liner and having at least one opening for receiving the fluid, and a piston member in fluid communication with the applicator assembly, the piston member operatively connected to the actuator of the applicator assembly and reciprocably disposed in the pump chamber for movement in a first direction toward the end of the housing and in a second opposite direction, the piston member including a hollow piston rod closed at an inner end and open at an outer end, the piston rod having a port intermediate the length of the piston rod opening into the interior of the piston rod, and a piston head mounted on the piston rod such that the port is between the piston head and the inner end of the piston rod, the piston head sealing against the inner surface of the pump chamber and defining a variable volume chamber between the piston head and the end of the pump chamber, wherein each movement of the actuator in the first direction reduces the volume of the variable volume chamber for generating positive pressure in the pump chamber and forcing fluid through the port in the piston member and to the applicator assembly for dispensing the fluid, and each movement of the piston member in the second direction increases the volume of the variable volume chamber and generates continuous negative pressure within the pump chamber for drawing fluid through the at least one opening in the end of the pump chamber and collapsing the liner.