Patent ID: 8305226

Claim:
A drinking-water level alarm lamp comprising: a watertight casing of an elongated capsule shape including cup shaped upper and lower ends of generally equal size and shape interconnected by a generally cylindrical body; a lamp located inside the cup shaped upper end; a rolling ball tilt switch including electrically spaced first and second cup shaped portions having a gap therebetween and movably mounted in the generally cylindrical body between positions parallel to and perpendicular to the generally cylindrical body, with the rolling ball tilt switch further including a ball rollable in the first and second cup shaped portions and providing an electrical connection across the gap and between the first and second cup portions; a battery; and a weight located inside the cup shaped lower end, with the battery located intermediate the weight and the rolling ball tilt switch; wherein the watertight casing configured to be placed in a water feeder so that when the water feeder contains drinking water, the watertight casing half floats above the drinking water in virtue of an inner space of the watertight casing and the weight, and when the water feeder that does not contain drinking water, the watertight casing lies horizontally at a bottom of the water feeder; wherein presence and absence of the drinking water in and from the water feeder change a position of the watertight easing, wherein the rolling ball tilt switch in the watertight casing is accordingly switched to turn on or off the lamp in a preset manner, thereby informing a rearer of whether the water feeder contains the drinking water or not.