| 摘要 |
<p>ADJUSTABLE MAST STEP A mast step is mounted on a traveler having two parallel linear bearings which ride in lateral grooves on a central track. The central track has downward enlarged vertical holes on 2-inch centers which hold detent balls. The detent balls are locked in their upper active position with a contact and lock the traveler in a preselected position. Depressing an operator pedal moves a slider bar within the track to align detent receivers with the openings in the track. As the detent balls drop into the receivers in the slider bar, the platform is released to move toward a new location. When the pedal is released, a spring tends to return the slider bar to misalign the receivers with the track openings. The detent balls are ramped upward out of the receivers into their upper operative position in contact with the downward opening locking recesses in the traveler.</p> |
