26 March 2021
26 March 2021, Comments Comments Off on The magnificent mover
The magnificent mover

Most successful inventions

Just once in a while an invention comes along that revolutionises the industry it is aimed at. In our first article of this series, we look at a prime candidate – the chassis mounted caravan mover. It might not be in quite the same class as the iPhone but its effect has proven equally lasting

Words Terry Owen

Years ago, there was a standing joke – what do all caravanners have in common? Well, apart from always getting to the front of the traffic queue, the answer was – a bad back! There was good reason for this since touring caravans had slowly got heavier over the years as manufacturers bowed to customer demands for ever more luxury and convenience.
Of course, in the USA, caravans and trailers had always been big and heavy, so it’s perhaps no surprise that the idea for chassis mounted mover originated there. A patent describing a powered mover driving the wheels of a trailer via friction with its tyres was granted to a ‘D Stevens’ as long ago as 1974.

Early forms of mover
In Europe the problem of manoeuvring heavy caravans was first addressed by motorised hitch trolleys and later, powered jockey wheels. One of the very first motorised trolleys was the so called ‘Mr Shifta’ that first appeared in the UK in 1989. It had a towball to engage with the hitch head and was powered by an on-board traction battery and electric motor. It worked quite well but was really too big and heavy to accompany the caravan on an outing. Nevertheless, for a while, it more or less had the market to itself and quite a few were sold.
The next development came from a UK aerospace company that had a product range in aircraft handling equipment. They saw a gap in the caravan market and launched a powered jockey wheel that temporarily replaced the caravan’s standard jockey wheel. Called the ‘Powrwheel’ it took its power from the caravan’s leisure battery or from a dedicated auxiliary battery. It was launched in February 1991 at the caravan show in Birmingham. Although much lighter than the Mr Shifta, it still weighed in at 20 kg, making it not too practical to carry around.
There was also the issue that chassis manufacturers were none too happy with the strain the mover could put on the jockey wheel mounting bracket which, in Europe at least, was not designed to take such forces. In 1999, a rival UK company launched their ‘Bigfoot’ jockey wheel that came with an optional bracket to allow hitch engagement, but it was clear that a better solution was needed.

Breaking the mould
It was another UK company, Carver, which broke the mould by designing a mover that clamped to the caravan’s chassis and acted directly on the tyres via friction rollers. Carver was already well known in the UK caravan industry for its water and space heating products so the new mover was a natural development. Carver was aware of the US patent, even referencing it in its own patent application.
Initial concerns about the cost of production were put to the test when an early version of Carver’s mover was demonstrated to the caravanning public in 1996. They were asked to write down how much they would pay for such a device if it ever went on sale. The results convinced Carver to go into production without delay!
Carver’s mover sparked a revolution when it launched the following year. People would stare in amazement as caravans moved under their own power, something never seen before. On level ground it was actually possible for the caravan to tow the car backwards, to the even greater astonishment of onlookers. Early versions came with a wired handset but a wireless version – the Mover II – soon followed.
In those days very few UK caravans came with shock absorbers and the mover motors occupied the space where the shock absorbers would have been. However, if Carver was to break into mainland Europe, where shock absorbers were the norm, a solution was needed. The result was to drive the rollers via a chain and sprockets, thus allowing the motors to move out of the way of the shock absorbers. Unsurprisingly, the new mover was called the ‘Euromover’.
In 1999, Carver sold their water and space heating business to Truma in Germany. However, the mover business was just too good to let go, especially with a twin axle version under development.

Dutch interest
At that point Dutch company IVRA was developing its own mover, helped by redundant Carver personnel. The result was the ‘Move Control’, launched at the London show in October 2000. It was novel in that the motors were mounted inboard, away from any muck thrown up by the wheels. The design also avoided any shock absorbers that might be fitted. Long, gritted rollers transmitted drive to the wheels, giving excellent traction. Later versions switched to aluminium.
It was also the first mover to feature soft start electronics – something that has since become standard on virtually all movers. The revolutionary design caught the eye of German manufacturer Reich, who bought the product from IVRA in May 2001.

Twin axle issues
In the meantime, Carver’s twin axle mover development continued to make progress. The problem with a twin axle caravan is that it naturally resists turning. Early experiments using a single axle mover proved less than encouraging.
To overcome the turning problem Carver realised it would have to find a way of releasing the sideways force that builds up on the inside wheels. The answer was to continually pulse the inside drive motor so the wheels moved a short distance in the same direction as the outer wheels. The result was a somewhat ungainly crabbing motion and a very large turning circle, but it worked. At this point, speed control was still some way off.
The other issue to be overcome with twin axle caravans was their sheer size and weight. Carver addressed this with more powerful motors and larger rollers for better grip. However, tests showed that, on a 25-degree slope, a really heavy caravan would tend to creep slightly; despite the worm gearing that might have prevented it. Carver therefore decided to go to the expense and complication of developing brakes for the motors.
The first public demonstration of Carver’s twin axle mover took place in a corner of the Birmingham show in February 2002. It featured an experimental type of metal roller with a special mesh for grip. The roller never made it into production but the mover soon did. Following independent tests in May, Truma finally persuaded Carver to sell. The new mover launched with Truma badging in the summer of 2002, giving a welcome boost to the sales of twin axle caravans.


Powrwheel Ltd formed – sales take off
Meanwhile, back in January 2001, the owners of the Powrwheel jockey mover formed Powrwheel Ltd, and launched a chassis mounted mover, the ‘Powrtouch’. It came in two versions, one for caravans without shock absorbers and a chain driven one for caravans with them.
To help gain market share the Powrwheel optimistically offered a five-year guarantee – this compared to just two for the Carver and Reich products at that time.
The marketing ploy worked and sales took off. So too did warranty claims, but Powrwheel lived up to its promise to get an engineer out to any stranded caravanner in the UK. Caravanners are a tight knit bunch and the word soon went round that, whilst a Powrtouch mover might let you down, the company would not. As a result, sales soared.
Powrwheel too had been experimenting with a twin axle variant of its mover and was keen to beat Carver to market. The new product launched in 2001, ahead of Carver’s version. It was basically the single axle model but with different control electronics. This simplified production and meant that there was no additional weight penalty.
The market was growing at a heady rate and Truma wanted its fair share. Initially, Carver continued production on their behalf, but soon the whole operation transferred to Truma’s HQ in Bavaria. Truma then decided it was time to take the mover to the next level.
Truma’s site at Putzbrunn contains a building with a basement whose access is via a long ramp set at 15 degrees – a commonly adopted gradient on which mover manufacturers do much of their testing. The building soon became home to mover development, with many prototypes being hammered up and down that slope. Its use was eventually replaced by a special test rig.
Up until this point all movers were engaged and disengaged manually, either by operating a bar with an ‘over-centre’ action or winding a nut that slowly moved the rollers in and out. The first could require quite a bit of force, especially if the two sides were linked together with a cross bar. The second could be tedious, with as many as 70 turns being required by some models.
There was a clear need to offer a motorised solution and the race was on to do so. In 2006 Truma introduced the SE (single axle) and TE (twin axle) models with the ‘E’ standing for electric engagement. At the same time Truma dispensed with gritted rollers in favour of aluminium alloy ones. These had a much longer life and had proved themselves over and over on that 15-degree ramp.
Truma’s design was a giant leap forward and it won the much-coveted Red Dot Design Award. Reich and Powrwheel responded with motorised drive attachments that could be retrofitted to their movers.
By now the success of the mover in sales terms was tempting other companies into the market. Dutch company Tradekar Benelux BV launched their Enduro brand in 2007. Produced in collaboration with German partner EAL GmbH, it sold well. Sales were helped by companies like Purpleline, who spearheaded marketing in the UK and other areas. The first design echoed the Carver unit but more advanced products soon followed.
Interestingly, up to this time, several manufacturers used the same motors and gearboxes. These were very similar, if not identical, to the ones from the original Carver mover and were made in the UK by a company called EMD (now part of Parvalux). They proved to be extremely reliable; so good in fact that they’re still in use on some models. Today Parvalux is a key supplier to the caravan mover industry, providing geared motors and even friction rollers.

Truma buys Powrwheel
Despite the competition Powrwheel was doing very well, aided by social media reports of excellent on-site support for those who had problems. The success did not go un-noticed by Truma, who bought the company in 2008, and provided the necessary support to drive its products forwards.
The result was the Powrtouch Evolution, a brand-new design that is more powerful and reliable than previous models. To quote MD Phil Clark, sales remained buoyant but warranty claims “dropped off a cliff”.


Mammut, the AL-KO mover
With all these movers coming to market, two major companies were conspicuous by their absence – chassis and running gear manufacturers AL-KO and BPW. These companies were in the enviable position of being able to modify their chassis to eliminate the need for clamping with its inherent reduction in ground clearance.
The obvious and quick solution would have been to partner with an existing mover manufacturer but instead AL-KO eventually decided to go it alone. This could explain why it was not until 2010 that AL-KO’s Mammut mover appeared.
Recognising the importance of the UK market, the launch took place at the Birmingham caravan show in February 2010. The newly modified chassis rails appeared from April that year, each carrying the letter ‘M’ to denote suitability for the Mammut.
The Mammut is unusual in that the control electronics are carried in the motor housings; there is no separate control box. This makes for a simplified installation and maintains interior locker space.

BPW chooses Reich
Rival manufacturer BPW, decided to partner with Reich. The new mover came to market in 2012, with BPW branding. It bolted to a crossbar running through specially cut holes in the chassis rather than underneath it, as with clamping systems. Following the 2017 DexKo Global takeover of BPW, chassis production ceased, and with it the IMC mover. However, Hobby currently does something very similar on the chassis it makes for its own caravans, with Reich once again providing the mover.

Brushless motors and a second Red Dot award for Truma
The electric motors used up to this point had one thing in common – they were all 12-volt DC motors with carbon brushes carrying current to a central armature. Whilst such motors can be very powerful, they do have a problem in that precise speed control is difficult.
Enter Truma’s XT mover, which launched at Dusseldorf in 2014. It uses three phase brushless motors with feedback such that the control circuitry always knows exactly what the motors are doing. The result is an efficient mover that will track straight despite one or more wheels going over obstacles.
The XT represented another huge leap forward and once again saw Truma win the Red Dot Design Award for one of its movers. That is perhaps why, despite being a premium product, it sold well, reaching 10,000 units by the beginning of 2015. Truma celebrated by producing a special version, all in gold.
A twin axle version of AL-KO’s Mammut launched at the Dusseldorf show in August 2015 but only as a four-wheel drive model. This is because AL-KO believes a two-wheel version can get stuck when climbing a kerb, if a driven wheel becomes lifted from the ground.
The Mammut is a high-end product and AL-KO realised it also needed an entry level offering, if it wanted a larger slice of the market. In 2016 the Ranger was launched at the Dusseldorf show. It features manual engagement and a clamping system to attach to the chassis.
In a further development the ‘Enduro’ brand launched a combined mover and levelling system in 2016. Basically, the mover levels the caravan side to side with the aid of a portable ramp and motorised steadies level it front to back. A crosshair of lights on the handset tells you when it’s level.

Excellent consumer choice
Today the choice of movers has never been greater. Truma offers a range of movers, topped by its ground-breaking XT – still the only mover to offer the efficiency of brushless motors. Truma’s Powrtouch brand is enjoying success with its Freedom and Evolution movers. Reich also offers a range of movers including some of the most powerful on the market. Some movers even have smartphone apps, in case you can’t find the handset.
Purple Line continues to market the Enduro brand along with the Quattro and E-go brands. The latter also offers a ‘plug and play’ mover. With this, the motor drive units are easily detachable and powered from a suitcase containing a lithium battery. The idea is that the suitcase and drive units can be carried in the car, significantly reducing the weight penalty on the caravan. Purple Line operates in several markets including the UK, Australasia, and the USA.
Back in 2009, Danish company Kronings entered the mover market with some nicely engineered products featuring software upgradeable control boxes. However, following bankruptcy and new ownership in 2019, Kronings now just offers the unique ‘Robot Trolley’. This is a motorised unit with a self-contained battery and rubber tracks that engages with a special bracket on the caravan’s ‘A’ frame. This is positioned to give greater down force than would be possible at the hitch, although the latter may be used in some circumstances. Originally launched and manufactured by Mover Technology as the Camper Trolley in 2010, development passed to Kronings when the two companies merged in 2014.
Interestingly, powered jockey wheels remain strong in some markets – Australia for example, where the more rugged chassis are better suited to this type of device. AL-KO even offers one with a hand operated ratchet, so removing the need for a battery.

Future developments
The question is – what next for our beloved chassis mounted caravan mover? There is no doubt it’s here to stay and that strong competition will continue to keep prices down, especially at the entry end of the market. We’ll undoubtedly see more brushless motors and more information passed back to handsets on things like battery voltage, drive engagement and fault diagnosis. Of course, if the idea of the self-propelled caravan ever takes off (e.g. Dethleffs’ e.home Coco), the chassis mounted mover would become redundant for those models.
Weight reduction will also be important as most of today’s movers are no lighter than the first models. We may even see a mover that can learn a parking manoeuvre and repeat it. Whatever happens, it’s going to be interesting!

Whilst all forms of mover have had a positive effect on the market, there is no doubt that the chassis mounted mover, first introduced by Carver, gave the industry a shot in the arm like nothing else. Although primitive by today’s standards, even requiring a connecting cable from the hand controller, it proved an instant hit with end users. But it wasn’t just end users that loved it, the dealers that fitted it did too, for its good profit margin, and the fact the punters could sometimes be persuaded to buy caravans that they might not have otherwise bought.
It’s no wonder that intense competition soon followed, with big players like Truma and Reich able to take the product to new levels of convenience and performance. Today, that competition has driven prices down in real terms, and consumers have a choice like never before. The result is that many people have been able to continue touring when they might otherwise have had to stop.
There is no doubt that caravan sales have benefited greatly, especially those in the heavier, more luxurious bracket. What’s more, bad backs through mauling heavy caravans are now a thing of the past!

Carver - the company that sparked a revolution

Carver is a family-owned business founded by Joseph Carver in Walsall, near Birmingham, in 1776. During its first 100 years the company begun manufacturing metal products and went on to produce munitions during the First World War. In 1959 the first Carver clamps were produced, forming an important part the basis of the business as it is today.
In 1967 the company moved to a new, purpose built, factory in the Brownhills district of Walsall. About this time, they began to manufacture space and water heating systems for touring caravans. It was so successful that Carver became the sole supplier of such products to the UK caravan industry.
In 1996 John Carver, a keen caravanner, saw the need for a chassis mounted mover and produced the first prototype. However, by 2002, Carver had sold all its touring caravan business to German rival Truma.
Today the Carver Group remains involved in the static caravan business, making gas and electric heating appliances under the Widney brand. The Group has also diversified into the heating, ventilation and air conditioning (HVAC) business.

Speed control

In the beginning there was no form of speed control. The drive motors were either on or off. This could make controlling the caravan tricky, especially in confined spaces. From late 2000 the problem began to be eased with the introduction of soft start and soft stop. This made the caravan much easier to control.
In 2010 AL-KO introduced its Mammut with infinitely variable speed control, the first mover to have this feature. The Powrtouch brand introduced a form of speed control in 2012 with the launch of its FM Electronics System. This allows the motors to be driven at 25%, 50% and 75%, as well as full speed.
Extremely precise speed control came with Truma’s XT mover in 2013 and its brushless motor technology. This really is good enough to allow an egg to be trapped without breakage.

Increasing power

As movers have developed, they have been able to cope with ever heavier caravans. There are two ways in which this has been achieved. The first and simplest is to lower the gearing. This has little or no effect on the weight of the mover but of course reduces speed.
The second is to use more powerful drive motors. However, this can mean more weight and this is an issue, as it eats into the caravan’s payload. Carver’s first twin axle mover had larger motors and weighed in at a whopping 42kg compared to just 30kg for the single axle version.
One way of getting more power out of a given size of DC motor is to go for four poles instead of the normal two. In essence this means an extra pair of stationary windings and brushes. The motor consumes twice the current but produces twice the torque. You just need to ensure it doesn’t overheat. This is exactly what Truma did when it brought out the ‘R’ versions of its SE and TE movers in 2009 (shown on the left here below)