A Pneumatic Lifting bag is an inflatable envelope-type device placed between the ground and an object to lift the object; it may also be used to separate objects and can have lifting capabilities in excess of 75 tons.

• A. Hydraulic jack
• B. Pneumatic lifting bag
• C. Air bag
• D. Chain hoist

Answer: (B)

Pneumatic lifting bags are inflatable envelopes placed between the ground and the object to lift or separate heavy loads. They operate by supplying compressed air into the bag, causing it to expand and raise the load. Because the load is spread over the bag’s surface, a relatively large force can be applied with controlled, rapid action, and multiple bags can be used together to share the weight. This setup also allows rescuers or operators to create space under or between objects, which is essential for placing cribbing, shoring, or other supports. Lifting capacities for these bags can exceed 75 tons, making them suitable for very heavy tasks.

This differs from a hydraulic jack, which uses fluid under pressure in a piston to lift—no inflatable envelope involved. A chain hoist relies on mechanical leverage and chains rather than inflation. Sometimes people refer to inflatable devices as air bags, but the specialized term for high-load, rapid lifting and separating in this context is a pneumatic lifting bag.