| 摘要 |
<p>1476525 Load-monitoring device EATON CORP 25 Sept 1974 [23 Oct 1973] 41648/74 Heading G1N [ Also in Division B8] A load monitoring and warning device for a crane includes a load cell 10 in one cable of a main lifting system, an alternative cell 11 in an auxiliary system can be selected by switch 12. The output from the load cell is compared with a reference signal so that when the load on the cable falls to a set proportion of the static load an output signal operates alarms such as a warning light 34 or an audible alarm 36. Thus warning is given if a load catches on an obstacle while being lowered. The reference signal is set by a digital switch 37 and is supplied to a switch 23 at input 24 and in a first position of the switch 23 is connected to input 28 of a differential amplifier 31, the signal from the load cell being connected to input 27. The warning device will then be operated if the load exceeds a value corresponding to the setting of switch 37. This position of the switch is used in lifting after which the reference signal is adjusted by operation of switch 37 to equal the actual load signal on lead 29. Switch 23 is then moved to connect lead 26 to input 27 and lead 29 to input 28. The alarm will then be energized if the load falls below the static load by a fraction determined by resistors R8, R9. The output of the load cell may also be used to provide a continuous display of the load on an indicator 19, and may be fed to another differential amplifier 22 which gives a warning if the load exceeds the maximum allowable value.</p> |
