Registers – Single axis – Concentric disk
Reexamination Certificate
1999-04-08
2001-09-04
Frech, Karl D. (Department: 2876)
Registers
Single axis
Concentric disk
C235S11700R
Reexamination Certificate
active
06283365
ABSTRACT:
THIS INVENTION concerns an indicator device, and particularly, though not exclusively, such a device adapted to serve as a dose counter for metered dose inhalers (MDI's).
MDI's include pressurised canisters containing drugs to be inhaled for the relief of, for example, the symptoms of asthma. Typically each canister contains 200 doses but conventionally provides no indication to the user as to how many doses remain available for use at a particular time. This results in considerable inconvenience and risk to the user who must, inevitably, carry a fresh replacement MDI in addition to the one currently in use thus to ensure that if the current one becomes empty there is a spare supply.
Thus there is a need for a dose counter for an MDI to indicate the number of times the pressurised canister is depressed to dispense a dose of the drug. Such a counter must count down, typically from 200 to zero, progressively as doses are administered so that the user can readily see how many doses remain.
According to the present invention there is provided an indicator device to provide a count of a series of like linear movements of a first part of the device with respect to a second part thereof; the first part comprising first and second rotational rings carrying indicia progressively visible on the first part; the first and second parts having inter-engaging spaced projections such that upon each linear movement of the first part the first rotational ring is indexed in rotation, and such that a upon a predetermined number of linear movements of the first part, the second rotational ring is indexed in rotation.
Preferably, the second part is adapted to be affixed to the base of a pressurised canister of an MDI, and the first part is captive on the second part and spring-loaded thus to be capable of depression relative to the second part and to the canister.
Still further, the rotational rings are concentrically arranged, and the first rotational ring includes an annular array of spaced projections engageable successively with two further annular sets of projections fixed with respect to the second part of the device such that the projections on the first rotational ring successively engage the fixed projections to cause the first rotational ring to index in rotation twice for each depression and release thereof.
Furthermore, the second rotational ring comprises a further set of projections engageable successively by a pawl attached to the first rotational ring upon each complete revolution thereof thus to index the second rotational ring by one increment for each revolution of the first ring.
Still further, the first part of the device comprises a cap adapted for linear movement but prevented from rotational movement in relation to the second part of the device, the cap including a profiled channel in which the pawl is adapted to travel during rotation of the first rotational ring, the profile of said channel causing the pawl to engage the projections of the second rotational ring once for each revolution of the first rotational ring, the cap including a window through which respective surfaces of the first and second rotational rings are visible in one radial location thereof whereby numeric indicia on said surfaces are progressively visible through said window.
REFERENCES:
patent: 3792242 (1974-02-01), Hanson
patent: 4599508 (1986-07-01), Smetaniuk
patent: 5482030 (1996-01-01), Klein
patent: 5505192 (1996-04-01), Samiotes et al.
patent: 5622163 (1997-04-01), Jewett et al.
patent: 5957896 (1997-08-01), Bendek et al.
Frech Karl D.
Samuels Gauthier & Stevens
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