| 摘要 |
An automatic rail clamp is provided with an indicator for visibly showing the extent of wear of the replaceable clamping jaw inserts together with a fulcrum shaft having opposed eccentrics about which the jaws rock. As wear of the inserts develops, rotation of the fulcrum shaft is effected in measured increments which, in turn, progressively shifts the eccentrics relative to the axis of rotation of the fulcrum shaft to thereby move the centers about which the jaws pivot. This operates to maintain the arc through which the jaws rock within a constant range, thus allowing the rail clamp mechanism to operate at smaller, more efficient toggle angles by keeping the toggle angle safe. A differential hand screw is provided for moving the jaws in the event of failure of the automatic mechanism for opening and closing the jaws to ease the manual effort required to turn the hand screw, particularly to release the jaws when the clamp is set by spring pressure into clamping engagement with the rail.
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