Time recorder for orthopaedic harness wearing - uses temp. and humidity sensors in harness to trigger mercury-filled capsule as time recorder

摘要

An electronic circuit with temp. and humidity sensor inputs provides a means of measuring the time that a neck-head harness for orthopaedic treatment, is in use. This enables the orthopaedic doctor to quantify the results of a course of treatment. A miniature thermostat with upper and lower temp. contacts responds to body temp. Humidity changes across terminals cause a Schmitt trigger stage consisting of transistors and resistors to respond. The thermostat and humidity trigger stage are combined in an AND function with the output recording stage. The latter is a graduated capsule containing mercury. When the output transistor is switched the electrolyte level changes.