Patent ID: 8009282

Claim:
An attachment angle measuring device measuring an attachment angle between an axle carrier rotatably supporting a wheel and an absorber comprising an absorber main body attached to the axle carrier and an absorber rod slidably inserted into the absorber main body, comprising: a first light projecting part projecting a light to a first reflection position on an outer peripheral surface of the absorber rod when the axle carrier is fixed at a predetermined measurement position, the absorber is attached to the axle carrier and the absorber rod does not contact any member except the axle carrier; a first light receiving part receiving the reflected light from the first reflection position; a second light projecting part projecting a light to a second reflection position different from the first reflection position on the outer peripheral surface of the absorber rod when the axle carrier is fixed at the predetermined measurement position, the absorber is attached to the axle carrier and the absorber rod does not contact any member except the axle carrier; a second light receiving part receiving the reflected light from the second reflection position; a first optical path distance calculating part calculating a first optical path distance between the first light projecting part and the first reflection position based on the reflected light received by the first light receiving part; a second optical path distance calculating part calculating a second optical path distance between the second light projecting part and the second reflection position based on the reflected light received by the second light receiving part; and an attachment angle calculation part calculating the attachment angle between the axle carrier and the absorber based on the first optical path distance and the second optical path distance.