| 摘要 |
An improved trailer tongue jack including an outer tube and an inner tube which is slidable within the outer tube. The lower end of the inner tube carries a terrain engaging member, such as a caster wheel or sand shoe. A nut is mounted within the inner tube and is threaded on a screw and the upper end of the screw carries a bevel gear which meshes with a second bevel gear mounted on a handle. The bevel gears are supported within a polymeric cup mounted in the upper end of the outer tube and the cup also serves to rotatably support the handle as well as the upper end of the screw and further functions, along with a thrust washer, as a thrust bearing for the screw. The jack also includes an improved locking mechanism for locking the jack in either a vertical or horizontal position. A U-shaped swivel bracket is secured to the outer surface of the outer tube and the lower end portion of a locking member is mounted for movement within aligned openings in flanges of the swivel bracket. The upper end of the locking member is engageable with a hole in a mounting bracket secured to the trailer tongue to lock the jack in position relative to the tongue. A torsion spring associated with the lower end portion of the locking member serves to bias the locking member to the locking position.
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