TAKING UP THE SLACK
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Haldex derives most of its income from automatic slack adjusters for brakes; in five years' time its well-established product will account for only half of its revenue. Tim Blakemore looks at the Swedish company's plans to diversify within the brake technology field T11E SAFETY arguments or automatic drum brake adjustment on any commercial vehicle are difficult to refute. No matter how frequently manual adjustment is carried out, it cannot possibly maintain the correct lining-to-drum clearance (and thus peak foundation brake
performance) as consistently as can a correctly functioning, reliable, automatic adjuster.
The words "correctly functioning" and "reliable" are key ones. If the automatic adjuster cannot be relied upon not to get up to tricks like winding off brakes or adjusting them too far so that they drag, then the arguments in its favour soon weaken.
No manufacturer recognises this better than Haldex, the maker of the world's best-selling automatic slack adjuster for S-cam brakes, the one with the initials SA B on its housing. These initials stand for the Swedish for Swedish Brake Regulator Company, and they have been appearing on adjusters made at Landskrona, near Malmo in southern Sweden since 1916.
The first SAB automatic slack adjusters were designed not for any road-going vehicle, but for rail cars. Nevertheless; they shared two fundamental design principles with the most modern truck and bus adjusters built at Landskrona: they adjusted only on the return stroke of the brake chamber and they had a mechanism which enabled them to recognise how much lever movement was due to the clearance between lining and drum and how much was caused by the elasticity, or free play, in the foundation brake mechanism.
It is important for an automatic adjuster to distinguish between these two causes of excessive lever movement. If thc elasticity, which varies considerably from one type of S-cam to another as well as with the brake's condition, is not taken into account the result is likely to be over-adjustment and brake drag. This is one of the problems which plagued some early designs of car and truck automatic adjuster and helped to give them a long standing poor reputation.
With 70 years' experience of snaking an automatic slack adjuster which overcomes this particular difficulty, Haldex may be expected to be looking forward to many more years of simply building on this success.
Design of the SAB adjuster is protected by patent. The unit has a widespread reputation for quality. Next month will see a celebration in Landskrona of the 5 millionth SAB adjuster to be made there. Annual production at that plant is now running close to the 500,000 mark, and a North American plant in Kansas is now adding about 75,000 to the figure.
Why, then, does Haldex's marketing directors Ake Nclander, confidently predict that within five years from now the product mix of his company will have changed to such an extent that at least 50 per cent of its revenue will come from companents other than the automatic adjuster for S-cams? Currently, hardly any does. After all, the trend among vehicle manufacturers is firmly towards automatic brake adjustment, not away from it, and the signs are that trailer manufacturers will soon follow suit.
Certainly, the company does not expect to lose up to 50 per cent of its world market share over the next five years to competitors such as Rockwell and Wabco. Nelander is evidently confident that the Haldex automatic adjuster will stand comparison with any rival product, old or new, and a team of engineers at Landskrona spends a good deal of time conducting durability rig tests to confirm that this is so.
What lies behind the company's rather surprising forecast are some of the radical changes currently taking place in the field of truck and bus braking and Haldex's strategy for responding to them. It is a strategy which promises to produce several innovative, air-brake related products from Haldex over the next few years.
As the demand for better, safer truck and bus braking systems intensifies, so automatic brake adjustment becomes more popular. But while this has been happening there has been a proncunced swing away from S-cam brakes — the only type for which the Haldex adjuster is suitable — to wedge or fixed cam sliding shoe brakes which both have their own integral automatic adjustment. Iveco's move to wedge brakes, for example, lost Haldex an annual order for around 60,000 adjusters.
Volvo's more recent abandoning of its own S-catn brakes on trucks in favour of Lucas C;irling's latest fixedcam sliding-shoe design, which Volvo calls the Z-cam, cost Haldex another 60,000 units a year. There have been some gains to partly offset these losses, including an important new order from Renault Vehicules IndustrieIs, but there seems little doubt that the general popularity of S-cam brakes for trucks and buses is on the wane. Disc brakes for heavy vehicles, promised for so long and now, at last, probably only just around the corner, may finally see them off.
Then there is the trend noted by the president of Haldex's parent group, Garphyttan HesseLilian, in the group's most recent report (1984), towards a "growing demand to deliver systems as opposed to single components." I le may have had systems such as anti-lock brakes in mind fur which demand is certainly set to increase. There is no doubt that electronic control of many commercial vehicle systems, including brakes, is going to be much more common in the near future.
The bout of mergers and takeovers in which the maker of SAB slack adjusters has been involved in recent years has put the company in a stronger position from which to respond to such market changes. In 1972 SAIl became part of a rich Swedish trading company called Sonnesons. By the late 1970s further mergers had led to SAB becoming a subsidiary of Volvo, which did not appeal one bit to SAB's two major customers, Daimler-Benz and MAN. They soon made it clear that buy important brake components and in the process reveal new model development plans to a subsidiary of on of their main rivals.
In 1983 Incentive AB, a Swedish conglomerate, stepped in to take control of SAB, and a subsequent restructuring led to SAB and Haldex, makers of electronic and mechanical instruments including taximeters and the Halda road computer used by rally drivers, being brought together as Haldex AB, a subsidiary of the Garphyttan Hesselman group. The two other main divisions of the group are Garphyttan, the leading supplier of valve spings, and Hesselman Elhydraulic, whose primary product is the electro-hydraulic power pack used by most European tail-lift manufacturers.
With partners whose expertise is in electronics and electrohydraulics, Haldex is in a better position to compete with major rivals Bendix and Wabco (Clayton Dewandre), which are both part of very large groups. Nevertheless, Haldex remains small compared with these and Nelander says it has no intention of trying to compete on a high-volume, low-price basis. Instead it is on the lookout for good ideas in the general area of brake technology.
Two of the company's most recently introduced products are good examples of the kind of idea which Haldex is keen to take through to the production stage in the future.
The Haldex twin-chamber air drier was tailored to meet the needs of PSV manufacturers and operators who have to keep platform height low.
The idea for the heated automatic air reservoir drain valve, which Daf now uses, came from a Haldex employee. Because it is powered via the stop-light circuit, this valve operates at a higher frequency than other types which are dependent upon air pressure build-up.
Haldex promises to reveal a lot more innovation in air brake technology quite soon.