Above: Pronal lifting bags and accessories. An airbag jack is made up of one or more inflatable lifting cushions for heavy loads
Irregularly shaped machinery, delicate load surfaces, and problematic site conditions underfoot can all create challenges for conventional lifting technologies used to lift static and mobile machinery for service for service on or off-site.
The OH&S issues exist with both on and off-road vehicles, ranging from forklifts and 4wds through to full-size individual trucks and fleet vehicles.
A simple, safe, and proven alternative solution to such challenges can be provided by light but extraordinarily strong seamless inflatable lifting cushions from the global Pronal elastomer product organisation, distributed in Australia by Air Springs Supply Pty Ltd.
“With such a diversity of applications, comes a range of different safety considerations,” says Simon Agar, General Manager for Air Springs Supply. “It’s important to use these powerful products correctly to ensure the safety of all personnel and the longevity of the product. Pronal and Air Springs have worked on a guide to safe practices, and we encourage anyone to reach out to us for expert advice if they are still unsure,” he says.
The first four steps
Lifting a load is easily achievable if the right safety practices are followed. The following four steps help ensure safety and will prolong the life of the pneumatic lifting bag for multiple tasks.
1. Determine the available footprint and required stroke. The stroke is proportionally linked to the space available. Each lifting bag has its own expansion limit, which is approximately half of its shortest side. Thus, in order for the bag to reach its full intended height, enough space must be provided for it to grow.
2. Determine the required force/thrust. Once the bag is defined in terms of dimensions, it is necessary to calculate the required inflation pressure by using the formula. Lifting force (F in DaN) = Pressure (P in bar) x Surface (S in cm²). Air Springs can assist with guidance, through its national network.
3. Determine the required accessories. The inflation stem/port is the key element to activate the bag. It can be located on the face or the edge (some restrictions may apply for some models). Therefore, it is important to let us know the preferred placement before finalising the design of your application.
4. Verify potential environment issues. Is there anything critical in the environment where the bag will be placed? Including food industry requirements / chemicals in contact with the bag / sharp edges close to the bag / temperature range requirements / and, according to the environment issues, some options will have to be proposed (including FDA (food approved) rubber, high temperature rubber, stainless steel stem/port)
Check the contact surface
With all lifts and shifts – smaller or larger – the contact surface is important. It’s essential to check the surfaces that will be in contact with the air cushion jack. First of all, these surfaces (ground or facing the load) must be clean, and free of protruding parts such as stones, gravel.
Second, if the surface of the load is not rigid enough, the cushion could deform it by inflating. The dimensions of this surface must also be considered. Indeed, if it’s very small (a cross member) or large in length but not very wide, then the force transmission is reduced. You must use wedges or lifting plates.
Remember that the addition of wooden or composite wedges is an advantage for two reasons, in addition to the protection of the airbag jack. First, the wedges transmit all the force of the cushion over the entire area to be lifted. Thus, the stabilisation of the load is enhanced. The second reason is that they increase the lift height.
Factors to consider with larger loads
When you need to lift heavy loads (such as big vehicles, static and mobile machinery, or debris) the load involved may be too heavy for hydraulic jacks, which, moreover, could not be inserted with limited space. Safety and stability are also major considerations, especially with irregular loads (a factor which applies to many maintenance, rescue, and recovery operations).
In these circumstances, an air lifting bag – even several depending on your application – may be selected with inflation accessories to provide a solution that is quick and easy to deploy, but also adapted into small spaces.
For maximum safety, the steps to follow are:
1. Connect your accessories to the air lifting bag for heavy loads
Pronal air lifting bag kits provide:
- a control box, with button or joystick,
- and an inflation line for each airbag.
Accompanying products are selected according to your application and the weight of the load to be lifted.
The first step for the lift is to connect the hose coupler to the end of the air lift bag. Then connect the other end of the inflation line to the top of the control box. To complete the preparation of the equipment, you need to connect the air supply to the nozzle at the bottom of the control box. And there you are, you are ready to go the second step.
2. Position the pneumatic lifting cushion
One question now; how to define the location of your air lifting bag? It’s simple, first check that there is no sharp surface where the product will be in contact. Don’t place it on a surface of your load that would be susceptible to warping with pressure. Then, three scenarios are available to you:
- If the point of gravity is not at the centre of your load, use two pneumatic lifting bags to facilitate lifting and adjusting the pressure;
- If part of the load is to be lifted, position the cushions along the side to be lifted;
- And if the contact area is too small, you have to position the weight above the using a load plate.
3. Lift your load safely
After you’ve linked your accessories to the pneumatic lifting bag and installed it, it’s time to lift! First, taking advantage of your cable length of 5 or 10 m and your control box, back off from the lifting area.
In addition to protecting workers, this distance will allow you to stay safe and also allow good general a general view of your application.
Once away, all you need to do is:
- press the green button on your + button cabinet;
- or open the valve for simplified control;
If you prefer to go on a button or joystick box, you will be able to adjust the pressure of the airbag. Typically your load is lifted off the ground, in less than two minutes without effort when:
- undertaking maintenance of your machine or vehicle,
- changing the wheel of your truck or tractor,
- or the rescue of individuals stranded in the rubble.
But be careful, the airbag is a lifting system, not a wedge. Where work under the load is absolutely essential, safety requires the use of a wedge or a jack stand, for example.
4. Deflate and remove the air lifting bag
When it’s the time to deflate the Pronal lifting bag, always check that there are no tools or other objects under the load. Note also that deflation will take about twice as long as inflation. Stay in the safety zone, outside the lifting zone.
Ready? Press the button on your button cabinet or push the joystick down (if it’s a joystick box). If it’s a simple application, you can simply disconnect the air supply to deflate the air lift bag.
Once the load is completely on the ground, you can remove the deflated lifting bag using the handles. Don’t pull on the hose to retrieve it.
Conclusion
Lifting cushions are a powerful and precise technology, which can be used in situations where traditional lifting equipment like mobile cranes are unable to access the area. In order to optimise the use of lifting cushions, Pronal and Air Springs Supply advocate for an in-depth knowledge of all relevant safety practices.