Manitowoc’s new generation Grove all terrains are stronger, lighter and feature an emissions compliant single engine. John Stewart walks Cranes and Lifting through the range and highlights how well it has been received.
As a crane manufacturer on the global stage Manitowoc has to ensure that new product releases comply with various and differing regulations found in the major markets. This seems to be what happened with its Grove all terrain line-up.
John Stewart, VP and General Manager of the Manitowoc Australian operation, provides an insight into his company’s work on new products, the engineering involved and how the local market has received them.
Crane manufacturers must comply with the wide range of European and American road regulations and emission standards to sell cranes. This includes Manitowoc and the Grove mobile crane products. These increasingly strict requirements has meant a redesign of the all terrain range seen in Australia.
“To fit a new engine into an existing range might sound straight forward, but it isn’t,” Stewart said. “Not all new, low emission engines fit into the cranes existing envelop which leads to major redesigns which can lead to a lull in terms of product releases. But in 2015, shipments of the GMK 5250L – a completely new five-axle 250t machine – began arriving in Australia. Today we have over 20 in the country.”
The GMK5250L was the first of the new generation of cranes with the single engine and it allowed for a much stronger and lighter crane with an efficient engine.
“At Manitowoc we like to think we take the lead with innovative technology and the Megatrak suspension system is a good example. It’s an independent suspension without a solid axle underneath. Independent suspension is a much better system, it’s lighter and you don’t have a dead weight hanging beneath the crane,” Stewart said. “We can add more weight where it is needed versus having the axle dead weight which allows for our frames to be deeper as we don’t have the differential moving up and down underneath the crane. Our frames can be deeper which means you have a stronger crane with less material.
“We keep enhancing the Megatrak system by moving to ‘top steering’ and making weight saving measures so the cranes are getting more compact and lighter, but also stronger. The GMK5250L was the first big step in this direction.”
Manitowoc also ‘wrap’ or bend chassis frames from one piece of plate versus welding six or seven pieces of plate together. This saves weight and also strengthens the frame, as every weld could be viewed as a possible weak link.
The new designs had to take into account the Tier 4 interim as well as Tier 4 final engines but the engineers also had to plan for Tier 5, due in 2020, and ensure the engines will fit into the new design packages. “We use Mercedes engines almost exclusively in our all terrain range,” commented Stewart. “When you consider all the emissions technology for engines, you’d probably concede that Cummins is leading the way. That’s why a lot of the components in the Mercedes emissions package feature Cummins parts.”
The GMK5250L, like all the new generation all terrains from Grove, features a single engine concept that uses one angle drive going through the centre of the cranes swivel and directly into the variable pumps. The Grove single engine design ensures the most efficient use of the engines power with only one angle drive that reduces fuel consumption and noise. There is no oil flow or second drive sapping the performance of the crane functions. As a point of reference, competitive manufacturers’ one engine design see either a second angle drive with its additional mechanical linkages in the super or oil pumping through the swivel, so we feel our design is the quietest and most efficient,” Stewart said.
The GMK4100L-1 succeeded the GMK 4100L model, a two-engine machine with 60 metres of boom but it was just too heavy on the road to make an impact in Australia. So, Manitowoc sold a ‘non L version’ with a 52m versus a 60m boom, which was successful, but, according to Stewart, it was in a very competitive segment. “It was a strong crane but most manufacturers had a 50m-plus boom on a four-axle 100t or 90t machine. When we launched the GMK4100L-1, a single engine machine on a lighter, stronger four-axle chassis, we again maximise the capacity with the frame,” Stewart said.
“With the top steer Megatrak system you steer through the chassis frame and are maximising the weight savings with the independent suspension.”
The original design allowed enough room beneath the chassis frame for steering arms. The new design repositions the steering to allow differentials to be mounted directly to the frames, providing a deeper, stronger frame with less weight.
“In terms of weight, the European standard is 12t per axle, but realistically that’s difficult to achieve. The Europeans have been much more stringent with the enforcement of weights,” Stewart added.
“So, starting with the GMK5250L, we reduced the target from 12t per axle to 11.8t per axle which has really helped dramatically in Australia. Now all the cranes are extremely road-able, the weights fit Australia very nicely. In fact, the last six or seven cranes have just driven onto the weighbridge and straight off again in less than a minute. Before, it would take 30-40 minutes to move weights around to get the weights right.
“All the cranes are extremely easy to get on the road including the GMK4100L-1 which features 60m of boom. This model has been on the market since 2017 and we have over 25 cranes in the country.”
The latest crane in the new generation of Grove all terrains is the five-axle GMK5150L. This is a direct replacement for the GMK5130L-2, and introduces a new class of crane at 150t.
“The GMK5150-L is another brand new crane from the tyres up and improves capacity, has a 15 per cent to 20 per cent better load chart with the same counterweight, the single engine design and a little less overall gross vehicle weight. So we’re getting 150t capacity from the same package with 15 per cent to 20 per cent better load charts by maximising the weight saving and strength features,” Stewart said.
“The GMK 5150L arrived in Australia last September and we now have over 25 cranes operating with customers or on the water. With the weight targets of 11.8 per axle, the machines have been well received even in Queensland, which was typically the hardest of states to get a boom over the front five-axle machine on the road.
The GMK 6400 was the first modern big crane with the single engine in the industry and Manitowoc recognised that with the amount of engineering advantages involved and the efficiencies obtained from electronically controlled engines, having one engine was the way to go. This provided an opportunity to consolidate the extra weight savings and put it where it would do the most good. Making the structure of the crane much stronger was a real game changer.
“Grove started the single engine conceptual idea back in 2009 and launched the GMK 6400 in 2012. To be honest, we weren’t 100 per cent convinced that this concept would be accepted so we simultaneously launched the GMK 6300L, the smaller brother to the GMK6400 which featured a traditional two-engine configuration. But, the single engine concept was well received and worked perfectly and now we are extremely confident that all the future cranes are going to be single engine design.”