HIGHWAY CROSSING GATE MECHANISM CIRCUIT CONTACT

摘要

A rotary switch operated by a cam having a lobe is disclosed. The cam is attached to a mechanism for rotation about the axis of the cam. A first switch contact member is positioned adjacent said cam and selectively makes electrical contact with a second switch contact member. The bracket attached to the first switch contact member contains a roller positioned adjacent to the cam for rotatably engaging the cam as the cam rotates. The roller is positioned with the bracket portion of the first contact such that the axis of the roller is movable from a first position to a second position as the switch changes from an open to closed or from a closed to open position. The bracket may contain an elongated slot which permits the axle of the roller to move within the slot as the switch changes modes. The slot preferably extends linearly and at an angle less than 45 degrees from a tangent line to the surface of said lobe adjacent the slope between said cam and said lobe. In preferred embodiments, 15 degree angles to the tangent are particularly advantageous. The switch is preferably operated in the main shaft in a highway crossing mechanism and is preferably used in the motor control circuit to drive the crossing arm upward.