Patent ID: 7484642

Claim:
A dispenser for dispensing a metered volume of a fluid product having: (a) a storage chamber for storing the fluid product; (b) an outlet orifice through which the fluid product is dispensable from the dispenser; (c) a metering chamber having: (i) an outlet opening which places the metering chamber in fluid communication with the outlet orifice; (ii) a transfer opening through which the fluid product is transferable between the storage and metering chambers; and (iii) a boundary wall structure which is cyclically movable between a first configuration, in which the transfer opening is opened, and a second configuration, in which the transfer opening is closed, each cycle of movement which commences at, and ends in, the second configuration resulting, when the fluid product is stored in the storage chamber, in a metered volume of the fluid product being transferred from the storage chamber to the metering chamber via the transfer opening and dispensed from the outlet orifice via the outlet opening; and (d) an actuation mechanism actuable by a user of the dispenser to cause a cycle of movement of the boundary wall structure, the actuation mechanism having a biasing structure which biases the boundary wall structure to the second configuration so that the boundary wall structure is disposed in the second configuration at the end of each cycle of movement caused by the actuation mechanism; wherein the dispenser is adapted such that, when the fluid product is in the storage chamber, movement of the boundary wall structure in a first phase of the cycle of movement from the second configuration to the first configuration results in an excess volume of the fluid product, comprising the metered volume and a surplus volume, to be transferred from the storage chamber to the metering chamber and return movement of the boundary wall structure from the first configuration to the second configuration in a second phase of the cycle results in a bleed arrangement bleeding the surplus volume from the metering chamber and the metered volume being dispensed from the outlet orifice via the outlet opening; wherein the actuation mechanism is manually operable; wherein the actuation mechanism has an operating member which is engagable by a user to actuate the actuation mechanism; and wherein the actuation mechanism is actuated in response to depression of the operating member into the dispenser.