| 摘要 |
<p>Lift Mast Assembly This invention relates to an improved visibility free lift mast which eliminates the problems of reduced lift height, upright strength and excessive guide bearing loading. The lift mast assembly has a fixed upright and a movable upright mounted on the fixed upright and elevationally movable relative thereto. A lower guide bearing is mounted on a lower end portion of the movable upright and an upper and intermediate guide bearing is mounted on an upper end portion of the fixed upright. The intermediate guide bearing is positioned between the upper and lower guide bearings a preselected distance spaced from the upper guide bearing. The movable upright is elevationally movable a first preselected distance at which the movable upright is contactable with the intermediate guide bearing and free from contact with the upper guide bearing and a second preselected distance at which the movable upright is free from contact with the intermediate guide bearing and contactable with the upper guide bearing. Thus an improved visibility lift mast with free lift has been provided which offers maximum lift height for a given upright length, superior upright strength, and sequenced roller loading for improved roller life. The lift mast assembly is particularly useful in a fork lift truck.</p> |
