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Jost MODUL enjoys happier lanin
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'Text to tyres, trailer-landing legs Lre probably the most neglected :omponent on an artic. Hauliers learly expect them to be naintenance-free—even if they Lren't. Brian Weatherley looks at vhat Jost has been doing to match ts MODUL landing legs to "real vorld" usage, and keep grease off he streets.
According to fifth-wheel and landing ; manufacturer Jost, the average artic riles around some 3kg of grease on —and during the course of a day's )rk inevitably some drips off. vironmentally, that's not good news, ver mind the problem of staying clean )ile coupling and uncoupling a trailer. That's probably why coupling makers far fifth wheel rubbing plates with nonease inserts. But it's not an easy sell, pecially as the typical 1:3 tractor/ iiler ratio means that it's difficult to pi from scratch with a clean truck and Ulu. However, operators could soon ve no choice in the matter.
"It may well be that legislation will ultiitely drive down the reduction in ease," warns Jost GB's outgoing maning director Lionel Morris. With that in nd, Jost has already developed a ige of low lubrication and "maintence-free" products. It's latest MODUL 'ding leg is certainly "greener". More portantly to the average artic opera', it also offers better performance, t least against corrosion. MODUL was launched in 2000 in a bid to rationalise Jost's previous E-series landing leg range that had grown to a bewildering 1,500 variants. The answer was a "one-size-fits-all" range—aka MODUL—which has one common tube for the inner and outer leg, allowing it to be used on a variety of applications but with a choice of different feet, back plates, crank handles and connecting shafts.
Through MODUL, Jost not only saves money on materials, it also saves on build time—with E-series it could take any
thing up to 50mins just to do all the pressing and welding for each leg (not a pair). With MODUL, it's down to 23 minutes. With MODUL we've halved production time," says Kurt Bauer, plant manager at Jost's Wolframs-Eschenbach factory in Bavaria.
Robotics
As there isn't much opportunity to engineer maternal out of a landing leg—you still need a leg, a mounting plate, gears and feet--the application of robotics has allowed Jost to further cut production overheads, "We've removed the problems of producing a previously huge range," says Bauer. "MODUL is designed to offer the same variety as the E-series but within a more sensible product core."
Externally MODUL is a very "clean" design with the winding gear incorporated into the leg tube itself (unlike the old E-series with its external gears). That means: • Fewer parts to deal with, so less maintenance; • The end to problems with sealing around the gears and attendant corrosion and lubricant leakage issues;
II Reduced exposure to gear damage from fork-lifts when loading as gears are well protected within the tube.
With E-series and its external gears there were also problems for trailer builders over whether to build the gearbox as a left or right-hand unit. With MODUL the gear leg's the same, whatever side of the trailer it's fated. The other good news for operators is that MODUL is no heavier than previous designs.
Currently 85% of Jost GB's new OEM landing leg sales are MODUL units. So if you're buying a new Montracon, SDC, GT Fruehauf, Gray & Adams, M&G or Cartwright semi you'll probably end up with them.
Like many new product launches, MODUL's wasn't exactly glitch-free. Early production units suffered problems with reports of gear jamming and excessive noise. The trouble was caused by a flexing plastic bush at the end of the shaft carrying the high gear wheel, which allowed it to lift fractionally leading to less than perfect meshing. The latest version has a welded metal bush that's solved the problem.
Remedy
"The remedy was very quickly brought in," says Morris. "We didn't walk away from the problem, we had a campaign change and helped customers. We got a lot of kudos by the way we addressed it."
However, there were still comments about MODUEs "feel", and noise. In response Jost reduced its original 25mm per turn lift to 15mm lift per turn (still up by 5mm per turn on the old E-Series) and revised the gear profiles. "Drivers did like the high speed bu didn't like the notchy feel of the gears ant the noise," Morris reports. "Our servici people were being called out on war ranty because people thought there wa a problere---in fact it had no effect a functionaliy, but it was not what opera tors had come to expect from Jost."
The revised, smoother-acting leg have been in production since Januar and a retrofit is available for operator who have pre-9009 versions.
As MOGUL comes with a 50% bigge grease reservoir (there are no gran nipples) providing lubrication to the crit cal area, the inner sleeve, and as a resu of the use of high-performance lubr cants, "no maintenance is required fo three years".
If you do have to add any grease t the gear pack it's a simple job of undoin the two screws on the top cover. Goo news for operators, and even bette news for the environmental brigade a the integrated design means less greas will end up on the road.