| 摘要 |
A liftarm assembly having: i) a mounting socket and base assembly for attachment to a support; ii) a vertically extending mounting tube non-rotatably but pivotably secured to the mounting socket and base assembly; iii) a sheave mounted in the mounting tube for rotation about a horizontal axis wherein the sheave projects laterally out of the mounting tube; iv) a tubular metal liftarm mounting in the mounted tube for rotation about a vertical axis wherein the tubular liftarm is devoid of internal pulleys and external braces and other protuberances; v) the tubular liftarm including a lower vertically extending linear portion for insertion into the mounting tube, a laterally extending cantilevered upper portion, and an intermediate portion joined to the upper and lower portions by smooth curves; vi) a fitting coupled to the outboard end of the cantilevered upper portion and including a sheave journaled for rotation about a horizontal axis; vii) a load line having its outboard free end secured to the cantilevered upper portion of the liftarm and it opposite inboard free end reeved about the sheave in the fitting, through the tubular metal liftarm and mounting tube, about the sheave in the mounting tube, and laterally out of the mounting tube for attachment to a suitable winch with the portion of the load line intermediate its point of attachment to the upper portion of the liftarm and the fitting sheave defining a bight; and viii), a sheave block and support hook suspended from the lower end of the bight.
|
