Heat cycle indicating device
AssigneeUltimate Medical Pty Ltd
InventorPhilip Stuart Esnouf
Life of this patent
Estimating the term…
Abstract
An indicating device for indicating the number of times in which a surgical fitting has been autoclaved, the device including a body which includes first and second sets of teeth and a bimetallic indexing ring having teeth thereon, the arrangement being such that on thermal expansion and contraction of the indexing ring, its teeth engage those of the body so as to rotate the ring in a step wise manner relative to the body so as to thereby indicate the number of heat cycles to which the indicating device has been subjected, the indexing ring being the only movable part of the device.
Claims12
An indicating device for indicating heat cycling, said device including:
- a body including projections in the form of first and second sets of teeth;
- an indexing element having indexing means for engagement with the first and second sets of teeth, the element being mounted for rotation relative to the body, such that on thermal expansion and contraction of the indexing element, the indexing means thereof engages said projections to cause a step rotation of the indexing element in one sense only relative to the body;
- wherein the first and second sets of teeth are located in spaced planes which are perpendicular to an axis of rotation of the indexing element and the indexing means includes a trailing edge tooth and a leading edge tooth which are respectively engagable with the first and second sets of teeth, the trailing edge tooth including an inclined edge and an axial edge, each tooth of the first set of teeth including an inclined face and a radial face, the leading edge tooth including an inclined edge and an axial edge and each tooth of the second set of teeth including an inclined face and a radial face, arranged whereby:
- (i) on thermal expansion of the indexing element, the axial edge of the leading edge tooth abuts the radial face of one of the teeth of the second set of teeth and the inclined edge of the trailing edge tooth fully slides over the inclined face of one of the teeth of the first set of teeth until the axial face of the trailing edge tooth at least partly lies adjacent to the radial face of said one tooth of the first set of teeth;
- and
- (ii) on thermal contraction of the indexing element the axial face of the trailing edge tooth abuts the radial face of said one tooth of the first set of teeth and the inclined edge of the leading edge tooth fully slides over the inclined face of a next upstream tooth, relative to the sense of rotation of the indexing element of the second set of teeth, until the axial face of the leading edge tooth at least partly lies adjacent to the radial face of said next upstream tooth,
- such that on thermal expansion and contraction, the indexing element is rotated by an amount corresponding to a pitch of the first and second sets of teeth.
Dependencies are inferred from the claim text.