Engine tachometer indicator with two pointers - has engine temp. controlled pointer to indicate max. permitted speed for that temp.

摘要

An engine tachometer has a scale (1) with the usual revolutions counter pointer (2). A second pointer (3) varies according to the engine temp. This second pointer indicates the max. permitted engine speed, which increases as the engine warms up. The second pointer has a movement of up to 180 deg.. Instead of a needle-shape, the second pointer may be in the form of a double segment in two distinctive colours to indicate a short-term max. speed and a lower limit for sustained speed.