| 摘要 |
<p>In a device for accurate time control of a locking means (14) in a vehicle safety belt having an extractable band which causes a rotatably mounted shaft (10) to rotate during the extraction, the shaft is provided with a sequence of marks (21) arranged to be read by a reading head (23) during the rotation of the shaft. The shaft (10) is provided with a number of stop teeth (13) adapted to co-operate with the locking means (14) to lock the shaft, so that the band of the safety belt cannot be extracted. The reading head (23) is connected to an electric circuit (18) arranged to enable activation of the locking means (14) only at the times when the point where the locking means is to be entered into the travelling path of the stop teeth (13) is situated in a space between two stop teeth. In this way, the locking means will always be entered into a space between two teeth, so that the risk that the locking means during the entering will hit a tooth and bounce outwardly is eliminated. This will make the operation of the locking device more reliable and faster. The shaft is also provided with further marks (24) arranged to be read by a reading head (26) which is also connected to the electric circuit (18) and intended to make it possible to determine the rotary speed or acceleration of the shaft (10). The marks (21, 24) are provided on a disk (11) attached to the shaft (10) or directly on the shaft, and the electric circuit controls the locking means (14) over a control means (16) depending upon the signals from the reading heads (23, 26).</p> |
