| 摘要 |
PURPOSE:To generate a signal for a long period by fitting a cushion material to the front end surface of a guide path that a sensing mass contacts. CONSTITUTION:A reduced speed sensor 1 is fitted to a vehicle body so that a cap 4 is in the front in the running direction of the vehicle; and the sensing mass 10 is held by a magnet 11 during a normal run in contact with the rear end surface 9 of a guide path 6. If the car body is reduced greatly in speed owing to a collision, etc., an inertial force in the running direction operates on the mass 10, which moves forth when the speed reduction exceeds a specific value. At this time, the gap between the mass 10 and the inner peripheral surface 3a of the guide path 6 is small, so air is compressed in the space in front of the mass 10 and the pressure in the space behind it becomes negative. Consequently, the forward motion of the mass 10 is reduced in speed and when the mass 10 abuts on the cushion material 8, the forward moving speed of the mass 10 decreases. Thus, the time from the contacting of the mass 10 with contacts 15 and 16 to its leaving is held sufficiently long. Therefore, the signal is generated for a long period.
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