Above: A Pronal lifting bag employed on tracked vehicle for maintenance
The wet weather that has disrupted work on building, construction, infrastructure, and mining sites in recent times has resulted in many machines and plant becoming mired in mud and debris from which it is difficult and expensive to extract them.
Trucks, cranes, civil engineering machinery and mobile mining machinery have been stuck in places where conventional overhead cranes can’t always operate alone, without getting bogged themselves. Similarly, pipeline work and installing construction fabrications can be hampered by difficulties in delivering stable fine movement on uneven or soggy ground.
Sometimes too, difficulties have been encountered in rescue, recovery, or maintenance situations where conventional hydraulic or pneumatic jacks with high point loads cannot be safely used on unsteady surfaces (or where they would just disappear into the ground if they were actuated).
“Sometimes there is insufficient room overhead to employ suitable cranes, even if they can be brought overland to a remote site. Sometimes also there is insufficient stability underfoot to employ lifters that produce high point loads, both on the ground and on the object being lifted,” says Pronal pneumatic lifting cushion Australian supplier Air Springs Supply, which offers this guide to their correct use for applications such as:
- Lifting heavy vehicles for recovery, inspection, and maintenance
- Levelling machines
- Levelling pipes
- Releasing trapped people
Guide to correct use
In circumstances requiring maximum controlled lift with minimum damage and no point forces, one solution may be Pronal inflatable lifting bags so powerful and durable they have been used to hoist damaged aircraft and lift derailed locomotives and rolling stock. The ultra-thin versions of these lifters are engineered to fit easily underneath tracked vehicles, trucks, forklifts and essential machinery for on-site recovery and repair, or for emergency rescue operations on soft ground or irregular surfaces. As well as straight lifting, they can be used for pressing, clamping, tilting, and guiding, exerting tons for force with kid glove delicacy.
Pronal is one of the world’s leading producers of lifting cushions, which have hoisted loads as diverse as aircraft on soggy fields, through to artefacts from the liner Titanic, 4km down in the Atlantic. The seamless inflatable range of CLP lifting cushions – available from Australian distributor Air Springs Supply Pty Ltd – are easily transported to remote areas by helicopters, light aircraft and 4WD service vehicles. They are actuated by compressed air cylinders or standard portable compressors (sometimes even vehicle’s own exhausts) to rapidly but delicately raise loads ranging from heavy vehicles and civil engineering machinery, to pipelines and plant, generators, construction beams, bridge components, building components, machinery, and resource development structures.
CLP cushions range from ultra-thin bags (just 20mm thick deflated) that can lift weights of more than 65 tonnes each, to powerful spreading cushions that can exert hundreds of tonnes of force to part plant and machinery components for servicing. Complementary low-pressure CPB Maxi-Lift cushions can be used on land and under water, offering greater strokes of up to 700mm (or 1400mm where a pair are employed).
Their durability in aggressive and remote conditions, where safety and reliability are paramount, is reinforced by construction with threaded layers coated with chemical-resistant elastomer, hot vulcanised under pressure in one operation,” says Simon Agar, General Manager for Air Springs Supply.
Advantages of airbag jacking
Once placed under the heavy load to be lifted, the airbag jacks are quickly inflated. If the stroke to be reached is substantial, they can be stacked in units of three cushions each. Whatever the size of the cushion chosen, even the largest capacity, the deflated thickness remains low (a maximum of 25mm, so it is a practical and realistic solution across a wide spectrum of lifts).
The large contact surface of the bags provides stability and evenly distributed thrust. Its flexible rubber surfaces provide protection for the load (frame, body, etc.) so that the structure does not deteriorate or is damaged by point forces during the lifting or placement. In addition, the remote-control box allows the user to stay away from the lifting area. Thus, the operator can work in complete safety. The load is lifted smoothly and controllably.
Smoothness and control are major advantages for lifts of both mobile plant and static infrastructure, such as lifting or shifting pipelines, where the movement required may only be millimetres – but the precision required is very high.
For example, while CLP 67 cushions can each provide up to 67 tons of lifting capacity (enough for each cushion to hoist a decent size truck) they spread this force evenly over a broad area of the pipeline being lifted, to give minute control and stability.
This fine lifting capability – already employed on Australian pipeline projects – gives absolute control of the lift and therefore great safety even in less favourable conditions. One Australian project involved 238 metres of pipeline passing through a gully, so there was considerable weight involved in a restricted space. Using a diesel 180cfm compressor, load sensors, and the gauges and valving provided with the bags, the pipeline was repositioned to obviate the effects of slope and ground.
With them, the vertical lifts and sideways shifts became a relatively straightforward two-person job, one each side of the pipe. The bags were easy to position and extremely robust.
Conclusion
The features listed identify the ideal airbag jack for particular needs. These adapt to all kinds of lifting applications whether for vehicles, machines, or any other load.
Features of the Pronal product include:
- Strokes from 70-585smm (CLP), with longer strokes provided by combinations of cushions
- In addition to standard sizes, specific sizes and shapes can be made to order to suit particular applications.
- Ease of use, with inflation either by compressor or simple air cylinders
- Inflation pressures up to eight bar, regardless of stroke (CLP models – CPB pressures vary from under one bar, depending on model)
- Non-slip surface providing maximum friction when stacking two cushions
- Control systems tailored to particular uses
- Compliance with Standard NF EN 13731 lifting bag systems for fire and rescue service use – Safety and performance.
Pronal equipment, such as lifting cushions, can be supplied with trailers, lifting bases and control systems developed to the demanding standards of Pronal’s world-wide customer base, including military and civil aviation applications.
For a visual guide, Pronal has developed a video, how to use a lifting airbag.