Patent ID: 7913864
Filing Date: 2011-03-29
Classification: B66C,Y10T

Abstract:
1. A load lifting assembly comprising: a load lifting support structure including a first horizontal beam and a second horizontal beam spaced apart from the first horizontal beam; a first main hoist mechanism coupled to the first horizontal beam; a second main hoist mechanism coupled to the second horizontal beam; a first hydraulic circuit configured to operate the first main hoist mechanism; a second hydraulic circuit configured to operate the second main hoist mechanism; a first equalization valve system configured to selectively connect the first hydraulic circuit and the second hydraulic circuit, such that the first hydraulic circuit is independent from the second hydraulic circuit when the first equalization valve system is not energized, and the first hydraulic circuit and the second hydraulic circuit are connected to a common hydraulic line when the first equalization valve system is energized; and a control element having a first control position to allow for independent operation of the first hydraulic circuit and the second hydraulic circuit and a second control position for energizing the first equalization valve, wherein the control element comprises a first joystick actuator.