A boom assembly for a hoist may include a flat surface configured to elastically deform in response to a load on the hoist, and a strain sensor coupled to the flat surface and configured to generate an electronic signal.

This disclosure provides a system and method for limiting a swing angle of a jib crane, the jib crane having a jib rotatably mounted to a mast. The device can have a collar having a collar height and a collar width, the collar being configured to be fit to the mast at a stop height. The device can also have one or more stopping tabs enagagable with the collar and configured to be positioned on the collar at one or more points about a circumference of the mast. The stop height can place the one or more stopping tabs in a position coincident with the jib to interfere with the swing angle of the jib. The method can use the device to limit the angle through which the jibe crane can swing unimpeded.

A tower crane has a control unit which operates a rotating mechanism, a hoisting mechanism, and a trolley in dependence on at least one angle of rotation, in dependence on at least one first angle of deflection, in dependence on the at least one second angle of deflection, and in dependence on a difference in angle of rotation.

A lifting rigging is provided including a yoke adapted for connection between a load and a suspension point; and a weight-bearing assembly mounted on the yoke, which weight-bearing assembly includes a spring module including a number of constant torque springs, and a yoke wire with a first end adapted for connection to the suspension point and a second end connected to the spring module and adapted to wind the constant torque springs when the yoke wire is subject to a pulling force, and wherein the weight-bearing assembly is configured such that the yoke wire bears the weight of the yoke when the lifting rigging is suspended from the suspension point.