초록 ▼

A hammerhead type of crane has a structural tower with opposed structural cantilevers extending horizontally therefrom and there is a horizontal track along which a load carrying trolley may move through the tower between limits near the outer ends of the cantilevers and a second horizontal track al

A hammerhead type of crane has a structural tower with opposed structural cantilevers extending horizontally therefrom and there is a horizontal track along which a load carrying trolley may move through the tower between limits near the outer ends of the cantilevers and a second horizontal track along which a counterweight may travel at the same speed and distance but in the opposite direction and with the load trolley and counterweight passing each other as they move through the tower from one cantilever to the other. The counterweight is moved by means of a cable that has its opposite ends attached to the counterweight and which between its ends is wound about a reversible drum arranged to selectively move the counterweight in one direction or the other. For moving the load trolley in a direction opposite to but at the same speed, a system of cables connected with the counterweight is provided which includes a shuttle trolley on each cantilever arranged to move in the same direction as the load trolley but at half the speed, while other cables transmit motion between the load trolley and the slower-moving shuttle trolleys. This arrangement (a) avoids many long unbroken spans of cables otherwise commonly used and reduces the hazards of an accident, (b) provides the opportunity of direct reeving of the bucket hold and close lines, and (c) reduces sag tension at the bucket, thereby reducing the bucket weight requirements and thus permitting greater payload.

대표청구항 ▼

A hammerhead crane having a vertical tower with a pair of horizontal parallel spaced continuous members extending through said tower near the top thereof, said members defining pairs of cantilevered tracks that extend laterally from the vertical center of said tower, said cantilevered tracks includi

A hammerhead crane having a vertical tower with a pair of horizontal parallel spaced continuous members extending through said tower near the top thereof, said members defining pairs of cantilevered tracks that extend laterally from the vertical center of said tower, said cantilevered tracks including a fixed end structure at each end thereof with a plurality of sheaves mounted thereon comprising: (a) a counterweight movably mounted on a first one of said tracks, a drum, cable means extending from said drum and attached to said counterweight to selectively move same between the ends of said first track; (b) a load trolley movable along a second one of said tracks; (c) a first and second shuttle trolley movably mounted on said second track and movable along said second track between a respective outer end and the middle portion of said second track, the range of travel of each shuttle trolley being one-half the total range of travel of said load trolley, a plurality of sheaves mounted on each of said shuttle trolleys; (d) a first cable attached at one end to said counterweight and reeved about sheaves on one of said fixed end structure and then toward said tower and about a sheave on said first shuttle trolley, and then anchored to one of said fixed end structure; (e) a second cable attached at one end to said counterweight and reeved about sheaves on the other one of said fixed end structure and then toward said tower and about a sheave on said second trolley, and then anchored to said other one of said fixed end structure; (f) compensating cable means attached to said tower and operatively connecting each of said first and second shuttle trolleys with said load trolley, the arrangement of said drum, cable means, compensating cable means, first and second cables being such that when said counterweight is moved in one direction along said first track, said shuttle trolleys will move along said second track in an opposite direction at half the speed of said counterweight and said load trolley will move along said second track at the same speed as said counterweight.