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Operators and suppliers talk tippers

27th April 1985, Page 37
27th April 1985
Page 37
Page 38
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Page 37, 27th April 1985 — Operators and suppliers talk tippers
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Which of the following most accurately describes the problem?

Tipper operators and suppliers reached a closer understanding of one another's problems at CM's panel discussion

EARLIER this year CM invited five people closely involved with tippers to meet around a table at our office in Sutton and discuss some of the problems currently facing tipper operators. The discussion was chaired by Tim Blakernore. Re presenting the operators at the meeting were Sam Dunnico and John Myers.

Mr Dunnico is transport engineering manager for TiIcon's north central area and wears a second hat as a transport man ager at Skipton. He is responsi ble for a fleet of some 150 vehicles, mainly eight-wheelers, but including some tankers and four-wheelers. Products carried by the Tilcon tippers include sand, gravel, stone, tarmacadam and hot rolled asphalt — black top and dry stone.

Additionally, Tilcon has lime hydrate tankers which serve water authorities on reservoirs and their water treatment plants. Mortar is carried in tippers, but the company operates some concrete mixers.

The company's road laying vehicles are currently working on the M62 and M621.

John Myers is managing director of J. H. Myers of Clitheroe, Lancashire, the company he founded more than 30 years ago, and is vice-chairman of the Road Haulage Association's tipping service functional group. His company operates 18 tippers — three rigids, the rest artics — and carries out all its own repairs and maintenance as well as building its own bodies.

Leyland, which holds the lead in the UK rigid vehicle tipper chassis market, sent two representatives. Robin Woolcock is UK operations director of Leyland Trucks, while Paul Wain is the company's chassis engineering manager, heavy trucks.

Mark Rouse came to Sutton to speak on behalf of the tipper body manufacturers. He is group sales marketing director of the Wilcox group, a leading aluminium tipper body supplier based at Peterborough. What follows is a summary of the views expressed at the meeting.

Weight v strength Tim Blakemore opened the discussion by asking each representative what he saw as the main priorities in a modern tipper specification.

John Myers said that weight saving was a priority: "Our profits are so wafer thin at present due to the competition and the depression of the past few years that we are looking for maximum payload on every load we take. I estimate that half a ton saved in tare weight is worth £4,500 over the life of the vehicle, five years."

TB: "Assuming that half a ton is not saved at the expense of durability?"

XVI: "Of course your tipping vehicle and body has to be strong and durable enough to hold the hardest commodity you are going to carry as well as having enough capacity to carry the bulkiest load. You have to consider carefully what you will be carrying when choosing the body specification and, to some extent, the chassis itself. if you are talking about a rigid, for example, has it got to have double drive or can you manage with a single drive axle? If you are carrying grain all day you can probably get away with a single drive which, of course, does cut down tare weight, wear and tear and capital outlay."

Robin Woolcock was not surprised by John Myers' views on how he might increase his earnings, but he wanted to know what tipper operators most wanted chassis manufacturers to do to cut operating costs.

"Is fuel consumption the number one item?" asked Mr Woolcock. "I think we all tend to live in this dream world believing that tipper operators do not do a high annual mileage. Well it isn't true. I looked up some warranty statistics this morning and they show that operators on normal on/off highway operations are covering between 40,000 and 50,000 miles a year. If you are doing more than that then fuel starts to become very important. I think there has been a feeling that fuel was not terribly important on tippers and that certainly isn't true."

JM: "Fuel represents about 30 per cent of my costs. It is the heaviest expense I have."

RW: "So it has to be the number one priority."

Paul Wain: "It is interesting listening to John's priorities. The weight point is something that we have always been. conscious of. Our philosophy for rigid tippers has always been that we should design a chassis frame that would need very little in the way of additional Stelling or bracketing to accept tipping equipment, unlike some other vehicles on the market which might offer a lower ex-factory chassis cab weight, but then do need subframes to carry tippers.

"We are very conscious of making a tipper a vehicle that can go off-road and not something that you have got to mollycoddle. It is a working vehicle that you have got to be able to drive on the road and then straight off-road, and in recognition of this we have made some additional test facilities at the Leyland Technical Centre. We have all our normal onroad, sign-off criteria and then for tippers and similar vehicles we have an off-road sign off, and also a tipping sign-off."

Mark Rouse: "I agree with John when it comes to weight. Unfortunately, there are still to this day some operators who select the chassis cab without considering too much the chassis weight and then come to the bodybuilder and expect him to be able to save the half ton he is looking for, which is not possible.

"Consequently, it has to be a happy compromise to provide a decent payload with acceptable durability built in.

"While at Wilcox we could say 'yes, we will build lighter bodies', it would not be to our benefit or to the customer's long-term benefit to do so. The extra couple of hundredweight saved in the first place could cost more in the long term in downtime and repairs."

Robin Woolcock said the greatest potential for weight saving on the chassis lay in the area of the driveline, He gave one example: "By making smaller engines more powerful you really can take big chunks out of your kerb weight."

But he acknowledged that "some operators like it, some don't. You have to offer them a choice. Now we have an engine a little over six litres giving 170hp, which we are finding for three and two axle vehicles is meeting a lot of operators' requirements. A great deal of weight is being saved because not only is it being taken out of the engine, but out Of the gearbox and rear axle as well.

"We are going down two routes. One of offering a premium specification 11 litre engine which will last forever at the kind of duties and weights we are talking about, and the second for a much smaller engine, the 400 Series, at 170hp which on power-to-weight ratio is fully satisfactory and which will also last the course, but obviously will not give the same kind of premium durability. We are finding that more and more people are going for the lighter weight specification because they find that these engines will run for five years trouble-free."

Robin Woo!cock mentioned the "exotic materials", such as carbon fibre, plastic and aluminium, which Leyland and other manufacturers had experimented with. He summed them up generally as "right now either technically unproven and would not give the kind of life and durability you want or are horrendously expensive.

"I think everybody agrees the subject of weight is a key one," said Mr Woolcock. But Sam Dunnico disagreed: "Over the years it has become more and more apparent to me, operating a large fleet of vehicles, that everybody seems to be discussing and arguing the weight factor and it does seem to be top priority for competitive sales. But as a fleet engineer I find this disastrous.

"It is quite unbelievable that people can be so naive as to expect a light vehicle to withstand the strenuous application and operation of our vehicles. I say to all suppliers of parts, chassis and bodies, 'if you want your product broken bring it to Tilcon — we will break it for you.'

"When I hear people saying we want to take a kilogramme off here, a kilogramme off there, lighter engine, lighter running gear, lighter transmission, lighter chassis and so on it makes me think that in this particular sector of transport the people do not go out into the field enough to understand the operator's problems. Perhaps they ought to look at our vprs (vehicle performance records) which are computerised, though I still use a parallel manual checking system.

"Everything that is made lighter falls to pieces quicker. It is as simple as that. The lighter the application, whether it is the engine, the chassis, the body, the cab, running gear or transmission, the more quickly it fails and I have to put it right, on a daily basis. Our vprs show how tremendously this bumps up repair costs. It is noticeable that older vehicles, with less technology and a more sturdy frame throughout, give lower costs. They will creak and groan, and you may have lost a half ton on payload, but your costs are terrific.

"I sometimes think the people in manufacturing do not know the first thing about the application of our vehicles in the field."

Robin WooIcock defended the manufacturers' position, or at least Leyland's, by restating his company's policy in tipper specifications of offering "horses for courses". He said: "We offer a lightweight chassis and a premium chassis. At this point the premium chassis is still the one that most operators go for, but I can see more and more that the lightweight chassis will become attractive, though probably not for the kind of arduous opera.tions Mr Dunnico is talking about."

SD: "We have had to go through a chassis re-flitching programme on all our B registration vehicles. And we are told the latest chassis are wonderful! It is ridiculous to say that we are making progress on chassis when they are cracking, breaking, stretching and groaning on every vehicle that we have. You can't put a tow rope on, you can't use a chain, you daren't drill, you must not put electricity through it.

"At every inspection — every month we find a crack at a cross member, across the gearbox member, across the wheel arch or the hanger bracket mounting. And the same with every FTA independent inspection we have on our vehicles. A

crack here, a crack there and SO on.

TB: "You are strongly suggesting then that it would serve many manufacturers well to spend a lot more time in the field?"

SD: "Undoubtedly."

Off-road testing Paul Wain explained how Leyland's engineers were striving to match simulated tipper testing with real operating conditions. He described Leyland's off-road circuit at its Technical Centre: "The only thing we have done to it is put some hard core into it. The problem with any off-road circuit is repeatability. You have got to have some level of stability in your track. You can't just let the vehicles plough it up.

"We have used the off-road circuit at MIRA, but it is not very good for trucks. It was not really built foithat sort •of vehicle. Ours is quite a good facility considering how small it is. We have a slurry bath and some undulation for example and it will take tippers, mixers and on/off road machines. It has been a big benefit to us. "One of the problems we had with the off-road circuit was with washing vehicles. We have had problems with some of our bogies, everybody's got problems with their bogies, but these get worse if you leave them dirty for a long time. You can get concrete dust in and water, and that was not the way we planned it."

SD: "We have more water over our vehicles than a boat."

PW: "There we have a problem in testing. We want to inspect the vehicle every day and we want a thorough inspection every week while it is on the off-road circuit but, because we want to make our tests realistic, we do also need to look at mud build-up. With due respect to the industry, tippers are not washed every day. We only completely wash vehicles once a week during the off-road test procedure."

RW: "We would be surprised now if the tests that we use are not representative of what operators do with their vehicles."

SD: "But some of the basics are not accounted for. I went to one experimental lab where parabolic springs were being bent 24 hours a day and they were really excited about this test. They were surprised when I said that I could break the eye end off that spring in one frosty morning with an unladen vehicle! I am not satisfied with the way that people come along and say that they have put five years' research into something and we break it in two months."

RW: "We always do in-fleet tests. We do not base all our results on what we do in our own test centre. But we have to have a test centre where we can do repeatable tests many millions of times on door handles and that sort of thing. However, we find that nobody breaks vehicles like an operator does and for that reason we aiways conduct user trials on anything before we sell it."

MR: "My view as a body supplier on this subject is that it is a case of building up to a standard rather than down to a price. There are in the bodybuilding trade new people who keep popping up fairly regularly with kits available from aluminium companies. They can put bodies together without any testing to any degree. A lot of people will buy on price rather than on specification."

Turning away from durability and towards non-hgv tippers, Robin WooIcock provided some interesting statistics based on last year's registration figures.

"Of the 52,821 trucks registered in the UK in 1984, 7,179 were tippers, that is 13.6 per cent of the total. Of those, 793 were skip carrying vehicles, 446 were mixers, leaving 5,940 outright dumpers and tippers. So about 11 per cent of the total market are rigid tippers. That means it is a very important market for anyone — certainly for us.

"The breakdown of that total by gvw is interesting. Of that 5,940, 2,246 are 7.5 tonne gvw tippers. That must be the likes of local authorities, utilities, small builders merchants, in other words people who are not tipping for a living, but who need a vehicle which will tip."

Sam Dunnico said that Tilcon uses several 7.5 tonne tippers, Fords and Bedfords, on its road laying work and they are not at all troublesome: "I wish I could run a fleet of 150 71/2-tonners. My problems start after that. The 71/2-tonners do not go on site.

"On the M621 today we are laying 2,500 tons of black top. We have got to finish by 6pm. I have 36 eight-leggers on the job. I would not dream of using anything else."

PW: "The engineering signoff criteria for a 71/2-ton tipper can be very different to a big one."

SD: "The most likely way for a 7.5 tonne tipper to be damaged is by overloading."

On-board weighers "I wonder if anyone has any strong views on on-board weighing devices?" asked Tim Blakemore.

MR: "At Wilcox we do fit load indicators, the type based on a load cell in the tipper hinge bracket and the front-end lifting bracket. We have been fitting these now for a couple of years.

"At the moment they are rather expensive. The demand is not as great as we thought it may have been at this stage, but people are obviously put off by the initial cost. You are looking at between £3,000 and £4,000. Very expensive, but on bulk blowing vehicles for animal feed deliveries with com partmented loads to farms it does offer a real advantage because it will register every time a quantity is unloaded, so farmers can see exactly what they have had delivered rather than have to rely on what the driver tells them.

"We have found recently that on air suspended tri-axle semi trailers it is possible to get a reasonably accurate indication of bogie weight by simply tee ing in a valve into the air system, in a similar fashion to the old system of teeing in a gauge to hydraulic tipping gear."

Paul Wain commented on the experience of Leyland Trucks' engineers with the latest gener ation of on-board weighers. "The major problem is reliabil ity and the drift of the equip ment we have used. Air suspensions are not really a problem. You know you are going to maintain constant height so you know what pressure you can modulate. The problem comes with steel

suspensions. We have played.

around with quite a few makes of load cells and we have not yet found a reliable one. There is one that is probably head and shoulders above the others and we and a brake company are testing it.

"The key thing we want to know as a vehicle manufacturer is what load the axle is carrying, both dynamically and statically. Once we know that we can, for example, control the brakes better."

TB: "Why exactly are the current devices not reliable?"

PW: "Most of them are strain gauges and the problem is electrical drift. We have similar difficulty with our own test equipment and neither we nor the strain gauge manufacturers have been clever enough to solve that, let alone when the device is operating in the sort of hostile environment Sam is talking about.

RW: "Surely in the day of the microprocesssor and shuttles to the moon we can come up with something more sophisticated than a strain gauge."

PW: "There is no problem with processing the information. The problem does lie with the gauge, but there is one type which does not use the normal foil construction, which is better than the others. That is the one being tested by us and some brakes people."

Sam Dunnico and John Myers confirmed that they could certainly use a low-cost, reliable accurate on-board weighing device and Mr Dunnico said that the best way he had found of checking weight was teeing an hydraulic gauge into the tipper ram.

He felt strongly that those who are trying to design on-board weighing devices should spend time with vehicles. He invited them to "come on the vehicles with us for a month or two. See where we get stopped and the stupid figures on which some prosecutions are based. Stupid figures down to 60 gallons of dery in the tank and whether the tank was 2in wrong on the chassis."

The best suspension?

The discussion turned naturally towards suspensions. Which was the best type for tippers — steel, rubber or air? Was air suspension likely to become increasingly popular for tippers in this country as it was in other sectors?

Sam Dunnico hoped it would not, "purely and simply from the point of view of maintenance. It certainly will not stand up to it. And on a bad site you will find a driver is a lot happier with a typical standard steel suspension. He is happier with the stability and control over the vehicle.

JM: "I think that rubber suspension is alright on rough sites".

Sam Dunnico disagreed. "You cannot get the same 'feel' with rubber as you can with steel springs, — not on a difficult site."

MR: These comments mirror a lot of response we have had from various operators in the last two or three years about suspensions. I think air suspension on tri-axle trailers will come, but air suspension on rigids is different."

RW: "On rigids we have had a significant demand for rubber over the last couple of years. I think it has come later on Leylands than it has on most vehicles because I think our bogies were better than others. Some people abandoned their steel bogies years ago and went to rubber because they had so many problems with them."

SD: "Eighty per cent of our .fleet is on rubber now."

TB: "Paul, if you were an operator and you were choosing a suspension for a six or eight wheeler, which type would you choose?"

PW: "I would go for steel and choose our T6 bogie. The major reason for my choice is that with a two-spring bogie you are going to get a better cross articulation performance, which is all about keeping your wheels in contact with the ground, and you do not need diff locks if you keep you wheels in contact. You don't need anything clever if you can keep all four wheels on the ground and pushing."

There was a clear consensus from all the speakers that a two-spring steel suspension for rigid tippers was the best choice for good traction off road — though rubber scored on low maintenance costs.

On the question of tipper stability the participants seemed unimpressed by any claims in this area for tipping semi-trailers.

Sam Dunnico was unequivocal. "As far as articulated tipping vehicles are concerned we just do not want to know, not on rough sites. No way will we go articulated in any shape or form. Nobody has come •up with a semi-trailer yet that can be deemed safe in the areas and conditions that we have to work in."

Out of touch The two operators had some strong criticisms of tipping gear manufacturers. Sam Dunnico told of a stormy meeting he had had with a certain, unnamed supplier, whose engineer had said, "you must use outside seals, do not use internal bore."

Mr Dunnico had then taken him to a site where lean-mix concrete was being laid and "the vehicles were working at an angle of seven or eight degrees — one side of the tipper was six or eight inches higher than the other. Hearing his rams screeching and groaning, he had got in his car and driven off in astonishment."

Was there enough liaison between tipping gear suppliers and chassis manufacturers?

PW: "We do talk to them. When we get an order we will get together with the body people and the tipping gear people. We do turn to each other for help on various things. We have an engineer who goes on visits to bodybuilders and makes sure we get involved with them."

John Myers joined in the criticism of some tipping gear suppliers' lack of understanding of what goes on "at the sharp end of the industry."

He said: "The chief manufacturer of tipping gear in this country will not take any notice of what you say to him. They have aluminium collars that split. I've seen the trunnions at the bottom of the rams break away. They will insist on outside seals which allow dirt to get in and they screech when working on a slope. On Barber Greene work you have got a problem when one wheel is down and one wheel up. I have told my drivers not to tip if they don't think it is safe. I would like to see some kind of air levelling system to keep tippers level. All it would need is an air bellows between the axle and the chassis. Once rams begin to screech, they are not going to last long afterwards and then it is going to cost you f'1,000 for a new tube."

"Some tipping gear manufacturers do not even realise that a driver needs a tipping control that will allow him to feather the body down," said Sam Dunnico. He added that it had taken others eight years to realise that, as loads lightened during tipping, feathered control was essential.

JM: "The best control valve was the old Pilot one, which is no longer made and was a screw valve you could control precisely. Now it is just a short lever, the body comes down quickly, and we wonder why we get fractures in the chassis?

SD: "I took an engineer from a tipping gear supplier on site and invited him to climb in a cab and tip the load gradually. He frightened the life out of himself. Why do tipping gear manufacturers seem to think that you go and splurge your load out of the back? Why do they think that is all there is to tipping?"

Horsepower or brakepower?

Two subjects raised 'towards the end of our discussion were relevant to operators in general — braking standards and the problem of wheel fixing failures.

Sam Dunnico thought that vehicle manufacturers today should be more concerned with brake power than they are with brake horsepower. He described the braking problems that many operators were experiencing as "scandalous".

Paul Wain said that Leyland was very conscious of the need to stop vehicles efficiently. He was confident that Roadtrain "probably has the best brake specification of any tractive unit available, it is something we do a lot of work on. The real prob lem is getting the right brakes within the total package, that is the ability to fit all the wheels and tyres you want and stop the vehicle."

RW: "Except for Roadtrain, on which we kept the Girling twin wedge, we effectively abandoned ever being able to find a brake which was acceptable to us from proprietary manufacturers and we went away and designed and made our own. So all our air-brake systems now, except for Roadtrain, come with our own new S-cam type brake.

"When we reverted to S-cam everybody said 'you are not going back to that are you?' But it comes back to what these gentlemen have been talking 'about. Nobody has found a better way of doing it yet. All we went out to do was try and design the best S-cam brake that we could."

Sam Dunnico said that brake maintenance costs on new vehicles over the past five years had increased by 50 per cent. "You either have a lining that wears out too quickly and does not wear the drum, but the drum suffers from heat cracks so you have to discard it anyway. Or you have a lining which is hard and a drum which is soft and you end up throwing the drum away and using the linings for the next year. Then you have brakes that won't come off. We have tried automatic adjusters, but they keep the brakes on and the driver doesn't know they are on half the time."

John Myers said that his brake maintenance costs had not increased so much but he had found that the only way to overcome braking problems was to strip them down every six months and pay close attention to them even more regularly. "We fit a harder lining on the leading shoe than we do on the trailing shoe and we find we get conformity of wear by doing that," he added.

How serious in the tipper sector was the wheel fixing failure problem which has been well publicised and is being researched by the Institute of Road Transport Engineers?

If Sam Dunnico's experience is typical the answer is very serious indeed. He said: "Not one working day goes by that I don't have to change one wheel stud, in a fleet of 50 vehicles."

John Myers talked of replacing at least two wheel studs each week.


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