Abstract: A totally pneumatic crane warning system is disclosed capable of use in oil well environments. The crane warning system utilizes a pneumatic function generator. The pneumatic function generator includes a means for receiving a linear pneumatic signal that may be representative of a boom angle and translating that signal to a non-linear output representative of the maximum load capacity of the crane at that angle. This function is accomplished through the use of a rolling cam machined to represent the functional relationship between the boom angle and the maximum load capacity at that angle. This relationship has been found to be non-linear in nature. A pneumatic control circuit is utilized in conjunction with the rolling cam to effect the pneumatic output signal that is representative of the maximum load capacity at a given boom angle.

Abstract: An overload indication device for a lever hoist comprises an operating lever consisting of a main lever and a handle having one end pivoted to the main lever, a spring for normally holding the handle in an aligned position with the main lever, a magnification lever for deforming the spring by the rocking movement of the handle by a force corresponding to an overloading and a warning device for warning of the overloading, such as a buzzer, whistle or colored indicator adapted to be operated when the handle rocks to assume an angular position relative to the main lever.