Demountable gantry, boom hoist and counterweight

  • US 4,081,081 A
  • Filed: 10/26/1976
  • Issued: 03/28/1978
  • Est. Priority Date: 10/23/1975
  • Status: Expired due to Term
First Claim
Patent Images

1. A demountable counterweight and back hitch assembly for a lift crane having a supporting bed with horizontally apertured mounting plates on the rear end thereof, a gantry pivotally mounted on the bed and a hydraulic cylinder connected between the rear end of the bed and the free end of the gantry, comprising, in combination, a counterweight having vertical web means with horizontal apertures therein for registry with said mounting plate apertures, locking pins for insertion through said apertures, linkage means interconnecting the counterweight and gantry for lifting the counterweight when the hydraulic cylinder is extended, said linkage means including a lift arm on the counterweight pinned forward of the center of gravity of the counterweight to a toggle link which is, in turn, pinned to a lift link connected to the gantry, said toggle link and lift link having intermediate end portions butted together adjacent the front edges thereof when the counterweight is being lifted, and adjusting means interposed between the toggle link and the front edge of the lift arm to prevent tipping of the counterweight as it is lifted, to maintain the toggle link and lift link in abutting relation and to facilitate registry of said apertures in said web and mounting plates.

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