Clinical glass thermometer having a stem and a bulb integrally formed therewith

Abstract

A monocoque clinical glass thermometer which constitutes a glass stem and a bulb formed integrally therewith. The thermometer has a straight opaque background strip embedded therein on the side of the capillary bore opposite from the lens. The strip extends from the upper end of the thermometer stem down into a wall of the bulb. The portion of the strip in the wall of the bulb is a straight continuation of the balance of the strip and is not twisted. The outer surface of the bulb is free from irregularities such as flash and preferably is cylindrical as in a clinical thermometer with a stubby cylindrical bulb or a long cylindrical bulb. The bulb and stem are not only integral, they are formed from a single piece of glass so that residual stress is at a minimum and so that the formulations of the glass for the bulb and stem are the same, thereby lessening the possibility that strain may be created during the lifetime of the thermometer.

Having thus described the invention, there is claimed as new and desired to be secured by Letters Patent: 
     
       1. A clinical glass thermometer having a stem of triangular cross-section, a capillary bore extending lengthwise within said stem, an opaque strip embedded within said stem and extending longitudinally thereof, and a bulb of circular cross-section, said bulb having side walls and a bottom wall formed integrally with said stem from a single piece of glass, a portion of said opaque strip extending into a side wall of said bulb, said portion of said strip in said side wall being a straight continuation of the balance of said strip in said stem, said side walls of said bulb having a thickness approximately equal to the thickness of said bottom wall, said side walls of said bulb joining said stem with no abrupt reduction of wall thickness. .[. 
     
     
       2.  A clinical glass thermometer in accordance with claim 1 wherein said bulb has a diameter equal to or not greater than 20% of the diameter of an imaginary cylinder circumscribing said stem..]..Iadd. 3. A thermometer as set forth in claim 1 wherein the diameter of the bulb is from 20% more to 20% less of the diameter of an imaginary cylinder circumscribing the stem..Iaddend.