Polar crane and related method
AssigneeHarnischfeger Corporation
InventorGeorge E. Thorsen
Life of this patent
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Abstract
Disclosed is a polar crane supported by a rail and having a bridge and a bridge-supporting end truck at each end of the bridge. Each end truck has, for either direction of revolving bridge motion, a leading wheel contacting the rail. In the improvement, the leading wheel of each end truck has a single flange and the flange is inward of the rail. Skewed crane "lock-up" is thereby substantially prevented. A related method for modifying a polar crane includes raising the first end truck away from the rail, removing a two-flange wheel (the leading wheel) from the first end truck and installing a one-flange wheel in place thereof.
Claims8
In a polar crane supported by a rail and having a bridge and a pair of spaced-apart linear bridge girders and a bridge-supporting end truck at each end of the bridge girders, and wherein each end truck is circumferentially-spaced from the other end truck, each end truck includes first, second and third wheels supporting the weight of the girders on the rail, the improvement wherein:
- the first wheel on each end truck is a leading wheel for a particular direction of revolving bridge motion on the rail;
- each of the leading wheels has a single flange which is inward of the rail;
- and
- as to each end truck, the second wheel is between the first and third wheels and has two flanges.
In a hybrid polar crane supported by a pair of linear, spaced-apart rails and having a bridge and a bridge-supporting end truck at each end of the bridge, the improvement wherein:
- the bridge supports a rotating trolley on a circular rail;
- the trolley includes two trolley end trucks, each trolley end truck is circumferentially-spaced from the other end truck, each trolley end truck is supported on the circular rail and has, for a particular direction of rotation of the trolley on the circular rail, a leading wheel and a second wheel contacting the circular rail;
- the leading wheel of each trolley end truck has a single flange and the flange is inward of the circular rail;
- and
- the second wheel has two flanges.
A method for making a polar crane for handling loads eccentrically-imposed thereon and including the steps of:
- providing a pair of end truck frames for attachment to a pair of linear girders, each frame having an inward side, an outward side and first, second and third wheel mounting positions;
- mounting a first wheel at the first wheel mounting position, such first wheel having a flange only toward the inward side;
- and
- mounting a second wheel at the second wheel mounting position, such second wheel having two flanges.
A method for making a polar crane for handling loads eccentrically-imposed thereon and including the steps of:
- providing an end truck frame having an inward side, an outward side and first, second, third, fourth, fifth and sixth wheel mounting positions;
- mounting first and second wheels at the first and second mounting positions, respectively, such first and second wheels each having a flange only toward the inward side;
- mounting third and fourth wheels at the third and fourth mounting positions, respectively, each of the third and fourth wheels having two flanges;
- and
- mounting fifth and sixth wheels at the fifth and sixth wheel mounting positions, such fifth and sixth wheels each having a flange only toward the inward side.
Dependencies are inferred from the claim text.