Spreader frame

A method of using a spreader frame having plural beams connected by corner assemblies, the corner assemblies having joints that permit relative rotation of the plural beams, the plural beams comprising outer bars and corresponding inner bars, each outer bar having a series of apertures and each inner bar having a spring-biased pin shaped and oriented to displaceably engage any aperture of the series of apertures, each inner bar slidably engaging each corresponding outer bar to form one of the plural beams, each beam of the plural beams being expandable, and for each beam of the plural beams each aperture of the series of apertures other than a selected aperture is removably blocked and the inner bar is slidable within the outer bar to bring the spring-biased pin in position to insert into the selected aperture to fix the length of the beam and the size of the spreader frame, wherein the spring-biased pins engage the selected apertures and the spreader frame is in a rectangular or square unfolded position, comprising the steps of:

• removing a fastener of at least one joint of each corner assembly;
• displacing at least one of the spring-biased pins from a corresponding one of the selected apertures;
• and
• allowing the inner bar or outer bar of the at least one beam to slide towards the corresponding outer bar or inner bar under the influence of gravity.

A method of unfolding a spreader frame, the method comprising:

• providing a spreader frame having a first pair of opposing beams and a second pair of opposing beams, each beam of the first pair of opposing beams being connected to both beams of the second pair of opposing beams by first and second pairs of corner assemblies, and each beam of the second pair of opposing beams being connected to both beams of the first pair of opposing beams by the first and second pairs of corner assemblies, each beam of the first and second pairs of opposing beams having selectable extended length settings, each beam of the first and second pairs of beams being in an initially shortened position;
• hoisting the spreader frame into the air so that the first pair of opposing beams is in a near vertical orientation;
• allowing the first pair of opposing beams to move into the selectable extended length setting under influence of gravity;
• lowering the spreader frame to a working height;
• locking the first pair of corner assemblies;
• hoisting the spreader frame into the air so that the second pair of opposing beams is in a near vertical orientation;
• allowing the second pair of opposing beams to move into the selectable extended length setting under the influence of gravity;
• and
• locking the second pair of corner assemblies.