| 摘要 |
<p>PURPOSE:To eliminate the touble of malfunction caused by the external turbulence of earth magnetism by bringing a plurality of iron piece detection sensors divided into the blocks of approximately an integral submultiple of the length of a log alternately on its outer periphery in the length direction, moving the sensors in the length direction almost per one rotation of the log and having the remaining iron pieces on the remaining undetected sites detect further. CONSTITUTION:Iron piece detection sensors 2a and 2b, divided into a plurality of blocks of an integral submultiple of its length and divided into two pieces of blocks of almost one-quarter of log 1, are mounted on the ends of movable parallel links 4a and 4b movable up and down through oscillating mechanisms 7a and 7b on the log 1. Also, a transversing mechanism 6 consisting of an air pressure cylinder 6a, a side rail 6b and the like is mounted on a bearing body 5 in a manner of being able to make movable parallel links 4a and 4b transverse approximately by an integral submultiple of its length.</p> |
