| 摘要 |
<p>An overload prevention and indicator system for telescopic boom cranes of the stationary and/or mobile types in which the boom is pivotally raised and lowered in vertical planes by hydraulic lift motor means, the system including first electrical circuit means responsive to complete a selected on of a plurality of circuits corresponding to the length of the boom, the plurality of circuits being respectively connected in series to a corresponding plurality of second electrical circuit means, each representative of a predetermined increment of boom length, responsive to angular position of the telescopic boom in the vertical plane. The plurality of angular position outputs of each second electrical circuit means are connected according to predetermined crane overload information to a plurality of third circuit means representative of pressure range increments, and a pressure switch responsive to fluid pressure in the lift motor means, which is indicative of boom load, is connected to successively operate said third circuit means as the fluid pressure in said lift motor means increases and actuate an indicator and render inoperative selected operations of the crane when the crane approaches an overload or tipping condition at the particular length, angle and load condition at which it is operating at any instant.</p> |
