| 摘要 |
An automatic speed sensitive speed bump having a base plate, a front plate hingedly connected to the base plate, and a torsion spring that biases the front plate upwardly. A rear plate is hingedly connected at its upper end to the front plate. The lower end of the rear plate is beveled and rests on a friction plate, which is hingedly connected at one end to the base plate and is biased upwardly at its other end by a friction plate spring. A strike plate having a reverse beveled end is connected to the base plate. When a vehicle exceeds a predetermined speed, the force of the tires on the front plate causes the rear plate to be driven downwardly rapidly enough and with enough force to depress the friction plate downwardly against the friction plate spring as the lower beveled end of the rear plate is received in the reverse beveled end of the strike plate, which prevents any further rearward movement of the rear plate and therefore locks the speed bump in place. However, when the vehicle is traveling below the predetermined speed, the force on the front plate causes the rear plate to be driven downwardly to a lesser degree and more slowly as the rear plate slides over the friction plate and onto the top surface of the strike plate. In this manner, the front plate and rear plate collapse to a horizontal position such that the vehicle does not experience a bump.
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