Intravenous alarm device

Claim 1

An intravenous alarm device for providing an alarm signal to indicate that a predetermined amount of liquid remains in a liquid dispensing container of the type adapted to be suspended from an arm, the intravenous alarm device comprising: attitude-sensitive transducing means including a mercury switch that defines a reference axis and that has two contacts between which mercury makes electrical connection while the reference axis is within a predetermined tolerance angle relative to horizontal, and including circuit means controlled by the mercury switch for producing such an alarm signal while the mercury makes electrical connection between the contacts; a structure including a casing and support means for supporting the attitude-sensitive transducing means; the support means including a board for supporting the mercury switch, and adjustable means for presetting the orientation of the board relative to the casing to provide tolerance compensation such that the alarm is produced only while the angle between the reference axis and horizontal is less than the tolerance angle; the casing having at a first point thereof a hanger portion to provide for suspending the device from such an arm, having at a second point thereof a holding portion from which such a liquid dispensing container can be suspended, and having defined at a third point thereof a device center of gravity; the hanger portion defining an axis of revolution perpendicular to said reference axis; and the first, second, and third points being spaced relative to each other to define vertices of a triangle such that the structure, while being suspended from such an arm and having suspended from it such a liquid dispensing container that is dispensing liquid, orients the reference axis at a time-varying angle relative to the horizontal with the instantaneous magnitude of the time-varying angle being dependent upon the weight of the liquid remaining in the suspended liquid container.