Improvements in instruments or apparatus used for determining the compression and explosion pressures of internal combustion engines

摘要

203,464. Pearson, J. L. Aug. 2, 1922. Piston and spring pressure gauges with automatic maximum measurements.-A gauge for measuring the compression or explosion pressure in the cylinder of an internal combustion engine has a maximum finger which is raised by the plunger of the indicator and then secured to its maximum position by the sideways pressure of a small spring. The cylindrical body A of the indicator is screwed into the sparking plug hole for compression pressures or in an adapter for explosion pressures, and houses a piston D having an extension I and a shoulder on which rests loosely the maximum finger H, the piston D being acted upon by a spring G inside a barrel B which screws on to the body A. The vertical face of the finger H adjacent the piece I is marked with a scale. When the compression &c. pressure acts upon the piston D the finger H is raised, but when the piston returns to normal position the finger H is retained by the sideways pressure of a small spring E so that the reading on the scale on the finger, level with the top of the extension I, gives the required pressure. In a modification the barrel K screws into the body J and is marked on the outside with a helical scale T. The barrel is screwed down until the pressure just fails to lift the maximum finger N, when the required pressure is read at the point where the scale T disappears into the body J.