Claims for Patent: 5,349,945

Summary for Patent: 5,349,945

Title:	Aerosol dispenser comprising an indicator assembly
Abstract:	An aerosol dispenser for use with an aerosol vial. The dispenser contains an assembly that indicates the quantity of doses dispensed from or remaining in the aerosol vial. The assembly comprises a rotatable indicator comprising a circumferential rack that is engaged by a worm-gear. Reciprocal movement of an aerosol vial within the dispenser causes rotation of the worm-gear which in turn causes rotation of the rack.
Inventor(s):	Wass; Anthony C. L. (Lincs, GB), Law; Brian R. (Leicester, GB)
Assignee:	Minnesota Mining and Manufacturing Company (St. Paul, MN)
Application Number:	07/790,373
Patent Claims:	1. An aerosol dispenser comprising a housing having a patient port, the housing being adapted to accommodate an aerosol vial equipped with a metered-dose dispensing valve that comprises a valve stem movable between closed and discharge positions, the dispenser further comprising a support block having a socket adapted to receive a valve stem and an orifice having open communication with the socket and the patient port, the support block being reciprocally movable relative to an aerosol vial accommodated within the housing, the dispenser having an indicator assembly comprising a rotatable indicator, the indicator comprising a circumferential rack and being mounted for rotation about an axis parallel to said reciprocal movement of the support block relative to an aerosol vial accommodated within the housing; a worm-gear engaging said circumferential rack, and a movement detecting member movable in response to said reciprocal movement, wherein movement of the movement detecting member in response to said reciprocal movement causes rotation of said worm gear and indicator. 2. An aerosol dispenser according to claim 1 in which the indicator comprises an annular rack. 3. An aerosol dispenser according to claim 2 in which the indicator comprises an annular rack mounted for rotation about the support block. 4. An aerosol dispenser according to claim 2 in which the rack comprises teeth, a spacer gap, and a spacer block to prevent more than one full rotation of the rack. 5. An aerosol dispenser according to claim 2 in which the rack comprises teeth and the worm-gear comprises a shaft bearing a worm mounted for rotation about an axis transverse to said reciprocal movement, the shaft further comprising an integral ratchet wheel which is selectively engageable by said movement detecting member to rotate the worm-gear, the worm meshing with the teeth of the rack to drive the rack upon said rotation. 6. An aerosol dispenser according to claim 5 in which the worm and ratchet wheel are integral. 7. An aerosol dispenser according to claim 1 in which the movement detecting member comprises a projecting finger fixed relative to one of an aerosol vial accommodated within the housing and said support block and selectively engageable with said worm-gear. 8. An aerosol dispenser according to claim 7 in which the projecting finger is fixed relative to the aerosol vial and said vial is movable relative to the support block. 9. An aerosol dispenser according to claim 7 in which the projecting finger is fixed relative to the support block and said vial is movable relative to the support block to selectively engage the projecting finger. 10. An aerosol dispenser according to claim 1 in which the movement detecting member comprises an aerosol vial accommodated within the housing. 11. An aerosol dispenser according to claim 1 in which the housing is provided with a viewing port through which the indicator is visible. 12. An aerosol dispenser according to claim 1 in which the indicator is visible through the patient port. 13. An aerosol dispenser according to claim 1 in which the indicator assembly further comprises means to prevent unwanted movement of the indicator means. 14. An aerosol dispenser according to claim 1 further comprising means to prevent actuation of an aerosol vial accommodated within the chamber prior to inhalation through the dispenser. 15. An aerosol dispenser according to claim 1 in combination with an aerosol vial. 16. An aerosol dispenser according to claim 1 in combination with an aerosol vial, said aerosol vial containing a self-propelled pharmaceutical formulation comprising a medicament.