Patent ID: 8464598

Claim:
A torque measurement device comprising: a power shaft that transmits rotary torque about an axis; a first wheel carrying angle marks, the first wheel being secured to the power shaft; a reference shaft including a first end fastened to one end of the power shaft and a free second end that includes a second wheel carrying angle marks and that is on a same axis as the first wheel; a sensor disposed facing at least one of the wheels and configured to provide a signal representative of angular variation between the first and second wheels; and a calculation member configured to determine torque transmitted by the power shaft based on the signal provided by the sensor, wherein: the first wheel includes first and second series of angle marks; and the second wheel includes third and fourth series of angle marks, the marks of the first and third series being mutually parallel, while the marks of the second and fourth series are mutually parallel while being inclined relative to a first axial plane containing the axis of the power shaft, the marks of the first series being inclined relative to the marks of the second series, whereby the signal provided by the sensor is also representative of temperature of the power shaft, and when the calculation member is configured to determine the torque transmitted by the power shaft based on a first angular difference variation between the first series of angle marks and the third series of angle marks, and a second angular difference variation between the second series of angle marks and the fourth series of angle marks, and the second angular difference variation differs from the first angular difference variation by an angular variation resulting from thermal expansion.