Iron-free curtain

Some say the old curtain-sider – a semi-trailer with a tarpaulin superstructure – is somewhat of a dinosaur in the ever-changing world of logistics and just-in-time transport. It has survived many a technological change, and it is still going strong.

Today, however, trailers are being loaded, unloaded, coupled and de-coupled much more often than, say, at the turn of the millennium; and cross-docking, speed docking and just-in-time delivery have become the norm. At the same time, transport companies have to adhere to the strictest load securing regulations in history, so the manufacturing industry had to react to ensure the old curtain-sider can still keep up with the times. 

The result is a vast array of new quick-release curtains that promise to be both strong and easy-to-handle, such as the Speed Curtain from Schmitz Cargobull, Krone’s Easy Tarp system, and the Hybrid System from Kögel.

Schmitz Cargobull arguably led the way in that regard, focusing on the automotive and beverage industry first and foremost. Both industries require numerous stops to load and unload per day, and unsurprisingly, that’s where the Speed Curtain can show its full potential.

Both middle stanchions and support laths are built into the curtain itself, waiving the need for a fixed middle stanchion as we know it from the common European curtain-sider. Curtain tracks at the top and bottom of the trailer guide the actual tarpaulin and allow for pushing away the stanchion as you open it – a unique feature compared to the German competition. The integrated stanchions make sure that the Speed Curtain meets the stringent demands of Germany’s TUV inspectorate, but they also require the cargo to come in a fixed shape, such as crates or boxes.

The driver needs to perform three actions to open or close Schmitz Cargobull’s new curtain completely. After this, they can quickly roll the tarp aside to make way for a forklift to load or unload the trailer. The opening width is exactly 8.75 metres.

However, drivers must be careful to ensure that the cargo doesn´t push the curtain to the outside, which might damage the system. To prevent this from happening, Schmitz also offers a curtain-sider with the Speed Curtain system mounted on only one side, while the other side still has a traditional tarp as a backup.

The Schmitz system can also boast pallet stop rails over the full length of the trailer that comply with the strict load securing requirements of German auto giant Daimler. Should the rim get damaged – for example due to an enthusiastic forklift driver – it can be easily replaced, according to Schmitz Cargobull. Then there´s the option of a sliding roof which can be opened to the front and rear for crane loading – but it has to be supported by extra posts as there are no traditional stanchions left to rely on.

According to Schmitz, there are no special maintenance requirements for this type of trailer. Our test model had a carrying capacity of 29.9 tonnes, including the additional weight of around 200kg that has to be added for the quick release curtain system. Opening the Speed Curtain took one minute and one second, whereas closing the trailer was done in 23 seconds only.

Also inspired by the automotive and beverage industry, Southern German trailer manufacturer Kögel has opted for a ‘hybrid system’ – indicating that opening and closing the curtain is possible both pneumatically and conventionally.

From the outside, Kögel’s quick release model still looks like a regular curtain-sider. Behind the scenes, however, the buckles are kept in place by tensioners to ensure the tarp always remains in the right place, which is important once the pneumatic system begins to tension the curtain. The compressed air needed is provided by the braking system; requiring additional air lines that run along the side of the loading platform.

At the push of a button, 19 clamping units per side turn to tension the curtain. It is, however, important to ensure the curtain is connected to all hooks to avoid damage to the system. When unloading, the hooks simply let go of the curtain again, all at the push of a button. And in case anything goes wrong, the curtain can be opened or closed manually as well. Hence the term ‘hybrid’. 

The Kögel system is clever and quite easy to operate. For instance, the trailer still has the normal set-up so you can lay down the posts in the traditional way. Kögel also developed a version with vertical stanchions, just like Schmitz did, leaving it to the operator to choose just how far they want to secure the load. In addition, the Kögel system can be opened over the full length of 11.4 metres, allowing for more space than the Schmitz model. Opening and closing, however, takes longer – on average 1:20 minutes top open it and 1:06 to close it again. All up, the Kögel trailer weighs in at 6.241 tonnes, resulting in a healthy capacity of 35 tonnes.

Germany’s second largest trailer manufacturer, Krone, also has a quick release system on offer; and with the curved curtain clearly visible on the side of the trailer, the Easy Tarp system certainly has a unique look to it.

Key to the Krone system is a thick and long cable going around the entire trailer, which is fixated in four different spots. Just like the Kögel model, Easy Tarp is based on a pneumatic system that can fixate the curtain at the push of a button. The Krone system also has stanchions in place, but the operator has the option to choose vertical posts mounted in the curtain as well.  The curtain opens and closes quickly and can boast some 11,5 metres of free space to load or unload the trailer. The entire system adds 100kg of weight to the mix, allowing for a load of 32.6 tonnes at a tare weight of 6,350kg. When the trailer is closed and the rope pulled, the trailer seems to be very tightly secured. Opening the curtain took our test driver 1:08 minutes, while closing was done in 1:15 minutes.

All three systems are still new to the European market, and it’s fair to say they  make the trailer heavier and more expensive to run. But for those who have to load and unload a trailer frequently, they turn out to be a real competitive advantage. While the Schmitz Cargobull system has won praise for its clean look, it is also more expensive than the competing solutions and adds more weight, especially if the system is used on both sides of the vehicle. The Kögel system, meanwhile, looks and handles like a traditional trailer. It is also cheaper and faster to use. The Krone system is not just as fast, but also quite simple and straightforward. Plus, the Easy Tarp can boast a very tight fit, which may lead to fuel savings in the long run.

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