| 摘要 |
<p>In a load system which involves a powdered chain hoist wherein raising or lowering of a load is effected by a rotating drive sprocket over which the chain is trained, the amplitude of motion due to resonant response of the load system as a consequence of coincidence between the natural frequency of the load system and the frequency of oscillatory excitation produced by the chain/sprocket drive is significantly reduced by providing an energy dissipation device in series with the load. This device involves a spring mechanism which permits a limited motion at the resonant condition, in combination with a controlled damping factor. The spring compliance of the device normally will lie in the range of about 1/2-3 timethe spring compliance of the active length of the chain at the resonant condition and the relation between the spring rate of the device and the effective damping factor is preferably such that the spring rate divided by the damping factor will be at least about .006 seconds. The device so tuned is also effective in rapidly attenuating the amplitude of the transient motion induced when the hoist is suddenly stopped or started.</p> |
