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Zorluk: OrtaLifting and Supporting Loads

When an engine hoist (shop crane) with an adjustable telescoping boom is extended from its shortest position to its longest reach position, what effect does this extension have on the maximum safe lifting capacity of the crane?

  1. The safe lifting capacity decreases because extending the boom increases the leverage arm and tipping moment on the crane frame.Cevap
  2. B
    The safe lifting capacity remains identical because the capacity is determined exclusively by the internal hydraulic pressure rating of the ram.
  3. C
    The safe lifting capacity increases because a longer boom arm provides greater mechanical advantage over the load.
  4. D
    The safe lifting capacity increases because extending the boom disperses the downward force over a wider base footprint.

Cevap

The safe lifting capacity decreases because extending the boom increases the leverage arm and tipping moment on the crane frame.
Engine hoists utilize telescoping boom arms marked with distinct weight ratings at each pin position. Extending the boom increases the horizontal distance between the suspended load and the front pivot wheels. Because torque equals load force multiplied by horizontal distance, the longer lever arm exerts greater bending stress on the boom and increases tipping risk, requiring the crane's safe working load to decrease accordingly.

Adım Adım Çözüm

1
Analyze the mechanical configuration of a telescoping shop crane boom.
Extending the boom moves the load attachment hook farther away horizontally from the vertical mast and front support wheels.
Lifting capacity depends on structural strength and torque principles where torque equals force multiplied by distance.
2
Determine how the increased moment arm affects the safe working load limit.
Greater reach magnifies bending forces on the steel boom and increases the overturning moment toward the front wheels.
To maintain safety margins against tipping and structural failure, manufacturers de-rate the safe working load at each extension setting (such as reducing a 2-ton rating at minimum extension to 1/2-ton at maximum extension).

Anahtar Kavram

Engine crane boom extension and load capacity de-rating principles
Tahmini Süre:1m 0s
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Konular

Lifting and Supporting Loads

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