| 摘要 |
PURPOSE: To surely prevent falling and to ensure load holding by issuing damage alarm to cause an operator to switch ON an emergency vacuum generator or automatically connecting the emergency vacuum generator when a pressure drops below a load time limit pressure in a vacuum lifter. CONSTITUTION: A vacuum lifter 1 is provided with an additional emergency vacuum generator 60, and connected through a conduit 61 to the inside of a vacuum tank 5. The emergency vacuum generator 60 is driven by a DC motor 63, and connected to a battery 65 by a pressure switch 64. A measured value receiver 67 generates a closing pulse to the pressure switch 64 when vacuum in the vacuum tank 5 is determined to be lower than a specified minimum value. In this way, the DC motor 63 is actuated to operate the emergency vacuum 60, and a vacuum level in the tank 5 is achieved again. If simultaneously generated vacuum is not enough, then damage alarm is issued from a signal generator 69.
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