Patent ID: 7448259

Claim:
An indicator device for sensing an angular position of a rotatable element of a machine, the rotatable element including a cam shaft having a central axis and being pivotable about the axis between first and second angular positions, the shaft being configured to displace a valve between an open position and a closed position as the shaft moves between the shaft first and second positions, the indicator device including: a first indicator member coupled with the rotatable element such that angular movement of the rotatable element angularly displaces the first member, the first member including a drive pinion gear connected with the cam shaft such that shaft rotation angularly displaces the gear generally about the shaft axis; a second indicator member coupled with the first member such that the angular movement of the first member linearly displaces the second member, the second member including a rack gear engaged with the pinion gear such that rotation of the cam shaft linearly displaces the rack gear between a first position and a second position; and a sensor configured to sense at least one of linear position and linear displacement of the second indicator member so as to sense the angular position of the rotatable element.