Nicotine delivery system

1. A nicotine delivery system comprising:

a housing that has a longitudinal axis and which defines a chamber that is configured to receive a plunger and has an outlet for the passage of a formulation out of the chamber;

an actuating mechanism comprising an actuator and an actuation member, wherein the actuator cooperates with the actuation member such that when the plunger is received in the chamber the plunger and the chamber slide relative to each other, parallel to the longitudinal axis, by a predetermined incremental distance in response to each operation of the actuator by a user to displace a predetermined volume of formulation from the chamber through said outlet;

a first biasing means that is configured to urge the actuation member in a first axial direction that is parallel to the longitudinal axis; and

a protrusion and a first track, the first track having a plurality of stopper surfaces,

wherein, in response to each operation of the actuator by a user, the protrusion is brought out of engagement with a corresponding one of the plurality of stopper surfaces, with the first biasing means consequently causing displacement of the protrusion relative to the first track in the first axial direction, bringing the protrusion into engagement with a consecutive one of the plurality of stopper surfaces, which holds the protrusion against urging by the first biasing means in the first axial direction, until a subsequent operation of the actuator by a user.

2. A nicotine delivery system according to claim 1 , wherein the actuator is moveable in a direction transverse to the longitudinal axis to cause the plunger and the chamber to slide relative to each other.

3. A nicotine delivery system according to claim 2 , wherein the actuator is mounted to the housing and comprises a button that is depressible inwardly towards the axis to displace the actuation member;

wherein the actuator is slidably received in an aperture in the housing, or wherein the actuator is pivotally mounted to the housing.

4. A nicotine delivery system according to claim 1 , wherein one of the actuator and actuation member comprises the protrusion and the other of the actuator and actuation member comprises the first track and wherein the actuator is moveable relative to the actuation member to displace the first track relative to the protrusion.

5. A nicotine delivery system according to claim 1 , wherein the actuation member comprises one of the protrusion and first track and the other of the protrusion and first track is held in a fixed position relative to the housing, and wherein the actuator is configured to rotate the actuation member relative to the protrusion to urge the protrusion away from the corresponding one of the plurality of stopper surfaces;

wherein the first track comprises a plurality of guide channels that each extends in the first axial direction and are arranged in a stepped formation; and

wherein one of each of the plurality of stopper surfaces is disposed at a first end of each of the plurality of guide channels.

6. A nicotine delivery system according to claim 1 , wherein the actuator is configured such that force exerted on the actuator upon actuation by the user is translated into a force that urges the actuation member in the first axial direction.

7. A nicotine delivery system according to claim 6 , wherein one of the actuator and actuation member comprises a protrusion and the other of the actuator and actuation member comprises a track that is configured to translate displacement of the actuator in a direction transverse the longitudinal axis into displacement of the actuation member in the first axial direction;

wherein the track comprises a guide channel that is angled with respect to the first axial direction and is configured to receive the protrusion; and

wherein the guide channel is formed between first and second guide members, a flexible member and a receiving member of the track.

8. A nicotine delivery system according to claim 7 , wherein the flexible member comprises a sloping portion that protrudes from a surface of the track and has a guide surface at an end thereof that is angled with respect to the first axial direction and is configured so that when the actuator is urged towards the actuation member in response to actuation by the user the protrusion is urged against the angled guide surface and is displaced relative to the track at an angle to the first axial direction;

wherein the protrusion is urged against the sloped portion of the flexible member when the actuator is urged away from the actuation member so that the flexible member flexes to facilitate movement of the protrusion relative to the track in a direction transverse the longitudinal axis.

9. A nicotine delivery system according to claim 1 , wherein the chamber is integrally formed with the housing, or wherein the chamber comprises a canister that is removably received in the housing; wherein the canister comprises the plunger.

10. A nicotine delivery system according to claim 1 , comprising a mouthpiece with an outlet channel fluidly communicated with the chamber of the housing to expel formulation therefrom;

wherein the nicotine delivery system comprises a pressure relief valve that opens to fluidly communicate the housing chamber with the outlet channel when the pressure in the chamber reaches a pressure set-point, the nicotine delivery system being configured so that the pressure set-point is reached when the plunger is slid relative to the chamber upon actuation of the actuator by the user.

11. A nicotine delivery system according to claim 1 , comprising the formulation in the chamber, wherein the formulation contains nicotine.

12. A nicotine delivery system according to claim 11 , wherein the formulation comprises tobacco.

13. A nicotine delivery system comprising:

a housing that has a longitudinal axis and which defines a chamber that is configured to receive a plunger and has an outlet for the passage of a formulation out of the chamber;

an actuation member that is configured such that when a plunger is received in the chamber the actuation member slides the plunger in a first axial direction that is parallel to the longitudinal axis into the chamber to displace formulation from the outlet in response to rotation of the actuation member relative to the housing;

a first biasing means configured to urge the actuation member in a first rotational direction; and

an actuator to hold the actuation member against urging by the first biasing means until actuation of the actuator by a user, whereupon the first biasing means causes the actuation member to rotate in the first rotational direction.