| 摘要 |
A module is provided for use with a drive mechanism particularly suited for plug-type railcar doors to prevent "overspinning" and "drifting." The mechanism disclosed is a double brake-type mechanism and includes a first rotatably mounted member. The first member is arranged to transmit force in either direction of rotation and is connected with an input drive mechanism. The drive mechanism includes a rotatable pinion gear carried on a rotatable input shaft extending generally parallel to the axis of rotation of the first member. The pinion gear is connected with the shaft by means which cause it to move longitudinally of the shaft to a first or a second spaced point depending upon the direction the shaft is rotated. At each of the points, there are ratchets which are freely rotatable relative to the shaft except when the pinion gear moves to engage them at their respective points. When engaged, the ratchets permit movement of the shaft only in one direction. The arrangement is such that should the driven mechanism being moving the member at a rate greater than the pinion, the pinion will move longitudinally of the shaft to engage the other ratchet wheel and prevent movement of the shaft in response to force input from the driven mechanism. One of the ratchets has an even number of teeth and one of the ratchets has an odd number of teeth. The profiles of the ratchet teeth on the ratchets are different.
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