Temperature compensating tangent assembly for a diaphragm gas meter

In a diaphragm gas meter tangent assembly which rotates about an axis to drive the meter valves and includes a tangent wrist connected to the meter flag assembly, a temperature compensating assembly for varying the radius of movement of said tangent wrist from said axis in accordance with variations in the temperature of the metered gas, comprising:

• a first bimetal element having a first end connected to said tangent assembly to rotate with said tangent assembly around said axis;
• and
• a second bimetal element having a first end connected to said first bimetal element second end and a second end connected to said tangent wrist;
• said first and second bimetal elements being configured as circular arcs, together extending less than 360.degree. and oriented with respect to each other to form an open C-shaped loop, and having the relative placements of their high and low expansion sides reversed with respect to each other and so configured that the path of movement of said tangent wrist with respect to said axis in response to temperature variations is along a nonlinear curve so as to maintain the valve timing substantially without change as said radius changes.