| 摘要 |
<p>GRADE CROSSING ASSEMBLY This disclosure relates to a railroad-highway crossing gate and signal arrangement having an elongated aluminum gate arm movable between a vertical clear position and a horizontal traffic blocking position. The elongated aluminum gate arm is attached by a breakaway connector to a gate arm bracket which is connected to one end of a pair of gate arm support members. A pair of adjustable counterweights are securely attached to the other end of the gate arm support members. A power operating mechanism including a permanent magnet d.c. motor and a gear train rotatably drives an output shaft which has its respective ends attached to the pair of gate arm support members for moving the aluminum gate arm between its horizontal and vertical positions. The d.c. motor is provided with at least one shaft extension portion for receiving ratchet wrenches for manually moving the gate between its clear and blocking positions and for receiving a torque measuring device for determining the torque that is required to lift the gate arm from its horizontal position to its vertical position and for estasblishing torque that freely moves the gate arm from its vertical position toward its horizontal position.</p> |
