Patent ID: 8180273

Claim:
A meandering detection device for contacting a subject and following the subject to detect meandering thereof, said device comprising: a tilt sensor disposed in a plane and including an emission part that emits light, and light receiving parts, the light receiving parts including a first light receiving part and a second light receiving part that define a first axis therebetween in said plane; and a contact device including a contact part, and a support part pivotably supporting the contact part, the contact part including a contact end part that contacts the subject, and a reflection part integral with the contact end part, the contact part defining on the reflection part a second axis parallel to the first axis so long as the subject does not meander such that the emission part emits light to the reflection part and the reflection part reflects a first amount of reflected light to the first light receiving device and a second amount, which is equal to the first amount, of reflected light to the second light receiving device to cause each light receiving device to generate an output indicative of the amount of reflected light received thereby, whereby meandering of the subject moves the contact end part and thereby tilts the second axis of the contact part out of parallel alignment with the first axis of the light receiving parts such that each light receiving part receives an amount of reflected light different from the first and second amounts and changes its output accordingly.