| 摘要 |
The apparatus has first, outer (12) and second, inner (14) telescoping tubular sections, a housing (30) attached to the outer section, a pinion gear (40) and actuating ratchet handle (46), which has a spring-biased ratchet mounted on it,rotatably and pivotally mounted on the housing, and a gear rack (32) attached at one end to the inner section and slidably disposed on the outer section at its other. An angle bracket (56) is mounted upon the housing, and a spring-biased pawl (80) is slidably disposed upon the gear rack and operatively associated with the angle bracket. The pawl and ratchet are normally engaged with the pinion gear to achieve the ratcheting extension of the gear rack and inner portion with respect to the outer portion. However, the ratchet may be disengaged from the pinion gear to permit the ratchet handle to be moved to a collapsed position parallel to the outer section and both the ratchet and the pawl may be disengaged from the pinion gear to permit the pinion gear to freely rotate, allowing the rack and inner portion to undergo free longitudinal movement. |
