Designing the crane industry

17 July 2019

As Hans-Dieter Willim retires from his position as head of design at Liebherr Ehingen, Stuart Anderson interviews the man who has for forty years played a key role in shaping the modern mobile crane industry.

Without doubt, over a career spanning 40-years—all spent at Liebherr Werk Ehingen (LWE)— Dipl. Ing. Hans Dieter Willim has established a well-deserved reputation as perhaps the mostaccomplished mobile crane design engineer in the industry. He is a unique likeable individual— youthful, light-hearted and approachable—with a smile and a joke never far away. But you will never meet anyone more passionate or knowledgeable about cranes.

Officially Hans-Dieter retired from design responsibilities in LWE in April 2017, but he agreed to stay on for a year to continue his work with the trade associations ESTA, FEM, and ICSA. Predictably, such a wealth of experience and knowledge could not easily be taken over by one man: so Dipl. Ing. Roland Bohnacker has taken over design responsibilities for crawler cranes and Dipl. Ing. Bernd Boos for telescopic cranes. From October 2018 to October 2019 he will be serving as a consultant to LWE responsible for the relationships with the FEM, ESTA and ICSA.

On May 20 and 21 2019, Stuart Anderson visited Liebherr Werk Ehingen to interview Hans-Dieter Willim. These meetings were arranged in recognition of the imminent retirement of Willim after 40-years’ service with Liebherr.

SA: Hans-Dieter could you tell us about your early life.

H-DW: I was born in Reutlingen, a medium-sized city about 50- 60km North of Ehingen. From 1969 to 1972 I attended the Technical Gymnasium (German academy preparatory for University education). From 1972 to 1973 I served in the German Army and then until 1978 I attended Stuttgart University where I graduated as Master of Engineering. As part of my education I spend three months at the Demag plant in Benrath, Dusseldorf working on shovel excavators where I met Alexander Knecht who, as you know, later became a managing director at Demag/Terex-Demag. We have remained friends ever since.

SA: Was there any family history in cranes or engineering?

H-DW: Not really. But when I was a young boy, I had made several crane models with a Maerklin metal modular (famous German metal modular and train model manufacturer) and that got me interested in cranes.

SA: Please tell us about your early years at Liebherr.

H-DW: I started at Liebherr Werk Ehingen in October 1978, joining the design department. At that time, Liebherr Werk Ehingen had been established about ten years and was manufacturing a broad variety of cranes including the LI series of industrial yard cranes, LT series of telescopic truck cranes, LG series of lattice truck cranes, LR series of lattice crawler cranes and LGM series of harbour mobile cranes (soon afterwards renamed LHM). In addition, a big part of the factory’s business was in ship cranes and offshore cranes. Dr Rudolf Becker had been recruited as managing director of engineering and together with Hr. Friedrich Bar, managing director of sales, had a great influence on Liebherr’s future development. These two men established Liebherr’s course focussed on new technologies and industry-leading crane sizes and types.

SA: What were the first projects on which you worked?

H-DW: The first was the development of an improved four-section boom for the 30t LTM 1030 two-axle all terrain. Liebherr’s first LTM had been introduced a couple of years earlier and had already started to sell very well. Unlike some competitors, the LTM 1030 and its predecessors featured separate cabs on the chassis and crane upper that would become the industry norm. My next project was on our successful 55t telescopic truck crane—the LT 1055. I designed a counterweight handling system controlled from the crane cab that employed the counterweight telescoping system to pick-up the additional counterweight slab that was carried on the front chassis deck for highway travel. At that time counterweights, including extra counterweights, began to be an increasingly important design consideration.

SA: And how did your responsibilities develop?

H-DW: In 1986 I was named as a technical expert by the German Berufsgenossenschaft (trade association). I was appointed General Manager of the Design Department for telescopic cranes and crawler cranes.

SA: When did you get involved in lattice crane engineering?

H-DW: By the 1980s, lattice truck cranes were being challenged by larger telescopic cranes, especially by our 200t LT 1200 introduced in 1980. In those days, crawler cranes were not a big part of Liebherr’s business but in 1982 we were awarded a contract by Ontario Hydro for what would— at that time— become the largest crawler ever built. This Canadian utility company needed a crane of enormous capabilities for the construction of nuclear power plants. The most critical specifications were a lifting radius of 50m to lift heat exchangers with unit weights of 356t into a reactor building 46m high. This resulted in a crane with a working weight of 1,700t including 700t of free-floating rope-suspended counterweight and with a maximum load moment of 18,000tm. This was the only derrick crane without a derrick mast: the 700t counterweight was directly suspended from the rearmost guy mast mounted off the main boom tip for the luffing jib. The crane’s main boom was 3m x 3.5m cross-section and elevated to a very steep angle - almost vertical – topped by a very powerful luffing jib and was named the LR 1600.

Unfortunately, when lifting a total load of approximately 400t to a height of 100m, the crane operator started to slew the crane carefully, but the electronic plug in cards were damaged by high voltage, therefore the slewing movement was not controllable. As the crane operator noticed that the slewing speed was much too high, he turned the lever smoothly to neutral but according to the damaged plug in cards the slewing movement was stopped immediately. This caused the load and the derrick counterweight to swing resulting in the boom to cork screw extremely. As I was on site to train the operators, it was my task to bring the load safely to the ground. The crane was officially given back to me and the area around the crane was blocked off. This was a diesel-electric crane and all hoist functions had been crashed too. With the crane in this precarious position on a nuclear power plant I had to calculate the required hydraulic pressure for the hoist drums to release the brakes manually. This was the first of several very ‘hairy’ situations in which I would find myself!

SA: How about mobile harbour cranes?

H-DW: I really enjoyed working on these cranes. Our first machines were diesel-hydraulic while our competitors were well-established with their diesel-electric machines. But we began to make headway with our cranes, which in those days could lower their towers for traveling under low bridges, etc., in the port. Of course, a few years later, in 1986, production of these cranes as well as the ship cranes and offshore cranes was transferred to our sister company in Nenzing, Austria.

SA: What about other developments in telescopic cranes?

H-DW: In 1983 we developed our first 300t telescopic, the LT 1300 truck crane using 2-D technology. We had also just developed our first range of (twoaxle) conventional rough terrain cranes of 60t and 80t capacity. Of course, we were a late-comer to this market and faced many well-established players with much higher production output and lower prices. So at first we didn’t succeed but now we are trying again.

SA: And by the mid-1980s, the all terrain crane was really gathering market acceptance.

H-DW: That’s right but in those days almost all of them were small two-axle cranes. But then, in 1981 came our big break-through when Herr Bar negotiated the contract for 333 cranes with Maschinoimport of the USSR valued at €188m. In many ways, that contract was a huge challenge for us. Firstly it carried massive penalty clauses for late delivery. The cranes were for use on the new gas pipeline involving working in very-soft, muddy conditions as well as at temperatures as low as minus 50°C! Fortunately, the company had already gained valuable experience of designing cranes for low temperature operation from our first major Soviet contract back in 1971. However, the customer’s delivery terms were viewed by many as ‘impossible’ and to achieve the schedule required the manufacturing support of several sister companies within the Liebherr Group. Critical to fulfilling the customer’s needs was the development of an entirely new concept a 55t capacity four-axle all terrain equipped with special tyre equipment and also with a ‘shaved’ crane cab to facilitate safe clearance during rail transport through tunnels. That crane, the LTM 1055, looked like nothing ever built before but it set LWE on a course on which we committed 100% to the all terrain concept. The following year, at Bauma 1983, we introduced a commercial market version of this crane rated at 60t capacity—the LTM 1060— which became a huge success and changed the face of the crane market. I was also deeply involved in the development of the 160t capacity, six-axle LTM 1160 all terrain introduced in 1984 which, at the time, was by far the largest capacity all terrain developed to date.

SA: And then came the Chernobyl disaster!

H-DW: Yes, another againstthe- clock critical challenge for the company. Following the reactor disaster of April 1986, we were asked to develop lifting solutions. The site was already home to several very high-capacity crawler and tower cranes (not of Liebherr manufacture) that had been massively contaminated and unfit for further service for the immediate future. The key machine that we supplied ended up being a specially-developed version of the LTM 1160 all terrain crane. Given the radioactive nature of the site, the LTM 1160s had to be equipped with radio remote control for all travel and crane motions. In addition, six television cameras were installed on the cranes, the electronic components had to be lead screened and the cranes were equipped with grapples. Liebherr also supplied remote-controlled drivable mini manipulators on crawler chassis that the cranes hoisted into position into the contaminated areas.

SA: But you were also advancing your crawler crane designs.

HD-W: Yes, also in 1986, Mediaco, a very good customer of ours in France, asked for a 400t crawler crane which had a crawler undercarriage that could double as a heavy-lift transporter for use in Cherbourg. This demanded that we design our first slewing ring quick connection for removing and installing the crane to and from its undercarriage. We also developed a new superlift wagon that was equipped with a single-axle line offering improved manoeuvrability compared to the two-line designs of the competition. The following year, I had to fly to Korea when the main boom erection winch at Hyundai’s 800t capacity LR 1800 crawler got ‘stuck’ leaving 112m main boom with 56m luffer in the air. I designed a special clamp to connect the luffing rope with one of the hoist rope. By winding up the hoist winch we could unload the damaged luffing winch. To change the winch (we had sent a spare winch by air freight to Korea) the remaining rope had to be unwinded from the damaged winch. As the rope was spooled during erection of the boom with extreme rope pull, a lot of twist was stored in the rope. Suddenly the rope jumped up and twisted several times. Now on one end of the rope the crane booms were hanging, the other end was looking like braided hair. I was going back to the hotel with a rope of the anti-two block and tried how to get the twist out. Next day we used a large forklift where we put all of the loose rope. By passing under and over the rope we could create eliminate the twist in the rope. After two weeks of hard work the crane boom was safely back to the ground.

SA: Liebherr has always pioneered the use of CanBus and electronics on cranes.

H-DW: Over the years these technologies have developed into one of our group strengths. Of course, not too many years ago, electronics and computers were far from as reliable as they are today, but Liebherr recognized their benefits and committed early. A big step forward, was the development of the LICCON control system, which was introduced in 1989. That set a course for us to optimise the broad range of functions and benefits available via electronics and computerisation.

SA: Meanwhile Liebherr continued to push the boundaries of crawler crane design.

H-DW: Yes. Again, it was Japan that required something extraordinary. I had spent quite a bit of time in Japan during the mid-1980s when Nippon Kokan ordered a 650t LR 1650. But in 1994 we were asked for a crane almost twice its capacity – 1,200t! This time it was our very good customer MIC and it resulted in the LR 11200. The customer required cranes to replace filter systems in tall chimneys calling for a height of lift of 224m! That was by far the tallest in the industry to date. We designed the crane in Ehingen but our sister company in Nenzing built both units.

SA: In addition, Liebherr Werk Ehingen has never confined itself purely to mobile cranes.

H-DW: That’s right. I’m fortunate that the company has often allowed me to ‘take holidays’ away from my crane duties. For example, I was deeply-involved for three years in the famous ‘Cargolifter’ project in 1996. The plan of the company that devised this project was to build a huge airship for long-distance transportation of heavy and large loads. Significant design work was completed on the first model – the CL 160 with a lifting capacity of 160t airship – but it was never built. However a giant hanger was designed and built on the former Soviet Airforce base at Brand- Brieson Airfield. This hanger alone represented an exceptional design challenge. It measured 360m long x 220m wide x 106m high. That was a very interesting ‘diversion’.

SA: And the sunshades!

H-DW: Yes, but this time designed and assembled here in Ehingen. The famous 12 giant sunshades ordered for the inner courts of the Mosque of the Prophet in Medina, Saudi Arabia. The first contract was placed in 1991 and they stood 13m high and provided shade over 300 square metres. They used high tensile steel for the structures and Teflon fabric for the membrane. Since then we’ve supplied many more. Another Japanese ‘diversion’ came in 1998 when LWE developed dieselhydraulic heavy-lift winches for the construction of the Kurushima suspension bridges. These were used to raise concrete bridge segments weighing up to 540t each and 30m width. Eight winches each with 2,800m long 60mm diameter cables were employed. Quite an adventure working at height over water!

SA: Meanwhile big developments in telescopic crane design!

H-DW: Yes. One of my favourites, and I feel most important, design developments – the new Oviform profile boom with Telematic telescoping system. We introduced this in 1996 on the new 160t capacity LTM 1160/2 all terrain. This new design allowed a six-section 60m boom using the electronicallycontrolled ‘Telematik’ singlecylinder system that reduced boom weight and increased lift capacities as well as increasing boom length. At first it was thought, by some, that such systems would only be suitable for larger-sized cranes and I had to work very hard to convince management of its merits. Of Course, now this design can be found across our entire range. By then my mentor, Dr. Becker had retired. He was ‘a real engineer’ who I truly admired. But I had refused to take-over from him as managing director of technology and consequently Dr Hamme was appointed.

SA: And your all terrain cranes continued to get bigger.

H-DW: You refer of course to the famous 500t LTM 1500 introduced in 1998. That was a most-exacting design challenge. In order to meet axle loads we had to get the centre-of-gravity within 2cm. As you know, our friends in China tried to develop cranes looking very similar to the LTM 1500, but failed to meet axle load parameters. Over the years we’ve continued to develop this great crane with its 84m boom and to date we’ve sold over 600 worldwide.

SA: You have a great reputation with customers around the world. How did you develop these relationships?

H-DW: I’m a strong believer in spending personal time, eyeballto- eyeball with customers. This is where ideas for patents come from. It is also where you discover the real problems that customers have and how cranes can be improved. Back in 1998, our good customer Thomen based in Hamburg had their 550t LG 1550 lattice truck crane stuck in a most precarious position on a jobsite in Dortmund. Mr Thomen called me and during the night I drove to the site to see what I could do. En-route to the site I saw another LG 1550 belonging to another local customer. To extricate Mr. Thomen’s crane another crane of similar size was required. I called the owner of the other LG 1550 I had seen on my journey and out of friendship, he stopped doing the job it was working on and sent it over and saved the day. That’s what makes our industry special and why personal relationships are so important.

SA: What about developments in the engineering tools and techniques at your disposal?

H-DW: A big breakthrough came in 2000 when we introduced 3-D design. That has really helped our design and manufacturing processes. The first crane to really benefit was the 750t LG 1750 lattice truck crane introduced in 2002. That crane also resulted from close customer contacts. This time it was Mr Nolte based in Hanover who came to us with a challenge for wind turbine work. The result was this crane which has a special carrier with its X-Type outriggers as a single roadable unit and the separately-transported crane upper. So far we’ve sold nearly 100 worldwide.

SA: Then came telecrawler cranes.

H-DW: Yes - one of my personal favourite types. In 2005 a good Czech customer came to us requiring a crane in the 100t class that could travel under low bridges. These bridges were too low for a wheel-mounted crane in this class so we suggested a crawler. He agreed on the basis that he would also order several regular all terrain cranes to help defray development costs. The project was not too much of a design challenge – we already had the 100t upper and boom from our all terrain crane and our colleagues in Nenzing were producing lattice crawler cranes with the right size of undercarriage. That year a customer in Japan wanted six such machines but also needed to haul the nacelle, etc., up a very steel hill. We developed a system where the LTR 1100s could transport these turbine components up the hill and it worked out perfectly. Another case of customer-driven crane development.

SA: Meanwhile, the 1,000t barrier lay ahead!

H-DW: Yes, for our all terrains that milestone was passed in 2007 with the 1,200t LTM 11200-9.1 – the first crane to feature a 100m long telescopic boom.

SA: And wind work continued to create new challenges.

H-DW: Indeed. This has become such a major application for large mobile and crawler cranes – especially here in Germany. As I have mentioned the 750t LG 1750 lattice truck crane and 1,200t LTM 11200 became major players in this theatre. We tried a crawler version of the LTR 11200 but that proved less popular. Large lattice crawlers continue to be the more popular option and we have developed a series of specialized machines to meet these needs dating back to 2006 with the 400t LR 1400/2-W and 2009 with the 600t LR 1600/2-W. However, where these narrow track cranes are not necessary, we’ve found our conventional crawler cranes are the most popular – led by the LR 1600/2 of which we’ve sold over 100 and the 750t LR 1750/2.

SA: You’ve also found great success with your compact all terrain cranes.

H-DW: Yes, although we were rather late entering this field, we’ve now found a very successful formula. The 45t LTC 1045-3.1. laid the foundations but since we introduced its up-date, the 50t LTC 1050-3.1, we’ve really found a winner. People really like its compact dimensions and power elevating cab. But there is another area of development that is not so closely tied to individual models but available across the line and also as retrofits. Developments such as our Vario-Ballast (counterweighting system) and especially the Vario-Base (Outrigger system) have proven really popular with customers. Where job site space may be tight and elements of the project not fully-disclosed, Vario- Base allows customers to take on projects with increased confidence that a particular crane can get in and get the job done.

SA: And what of your monster – the 3,000t LR 13000?

H-DW: After a slowish start, sales are becoming more regular. Of course, since the Fukushima disaster nuclear power plant work has all-but evaporated. But to date we have four in service and you’ll see a fifth in construction in the factory. We don’t yet have a customer but with a machine like this, that takes many months to manufacture, one has to build for stock in order to offer shorter delivery terms.

SA: And finally, on your career. how many patents do you have to your name?

H-DW: I don’t know. I lost count after 100. Of course there are the occasional cases of patent infringement but, for the most part, these can be resolved amicably.

SA: So, what do you plan for your future?

H-DW: I will continue to live and breathe my passion for cranes of course. I have my wonderful family and I love to travel. At weekends some friends and I offer help on our local area to fix old domestic appliances such as toasters, radios, etc. It’s fun.

SA: Hans-Dieter. Its been a real pleasure. All the very best.

Hans-Dieter Willim says telecrawlers are one of his personal favourite crane types. Like so many of his innovations, the LTR 1100 was developed based on specific customer requirements.
When Willim started at Ehingen, Liebherr built a line of industrial cranes, designated LI.
One of Willim’s first design tasks was developing an improved foursection boom for the LTM 1030.
The LTM 1055, designed as part of a 333 crane order from the Soviet Union's Maschinoimport 'looked like nothing ever built before', and marked Liebherr’s 100% commitment to the all terrain concept.
The LTM 1060, launched at Bauma 1983, was based on the LTM 1055, and 'changed the face of the crane market'.
The LT 1300 was Liebherr’s first 300t telescopic crane.
To help with the Chernobyl disaster, Willim designed a special version of the LTM 1160 with radio remote control for all travel and crane motions, and crawler mounted manipulators, designed to be lifted into the most dangerous areas of the site.
The wind industry demanded a range of high capacity, high reach cranes, such as this LR 1400 W.
Willim’s ‘monster’ crawler, the 3,000t LR 13000. While a downturn in nuclear construction has hit demand for cranes of such huge capacities, the company has already sold four and—with long construction times an issue for cranes this size—is building a fifth without a customer order in place.
Willim designed these folding sunshades for the Mosque of the Prophet in Medina. They were one of a number of ‘diversions’ from his day job at Liebherr, which the company was very supportive of.