| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable a proximity sensor to be detected certainly even if a wheel touches a detection head by holding the proximity sensor by means of a spring in such a state that the detection surface thereof may be positioned at an interval below the wheels running on rails. SOLUTION: In a supporter plate 17, a cylindrical supporting barrel 19 having its one end opened, and making the other end thereof to posses a bottom plate with holes, is installed sideways, with its open end upward, to the front end part of the plate body 18. A proximity sensor 23 is formed in such a structure as having its top end surface to act as a detection surface and having its other end side provided with a cord 26. In the proximity sensor 23, the detection surface of its detection head is inserted freely slidably upward. The flange 29 of a lower cover 28 is arranged on the bottom plate outside of the supporting barrel 19 as a slipping-off stopper, and it is always elastically jumping upward with its detection head projecting upward from the supporting barrel 19. In this way, even if the wheel (s) W may touch the detection head owing to heavy vibration, the proximity sensor 23 vertically descends elastically inside of the supporting barrel.</p> |
