Some Pointers to German Design Thinking
Page 42
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WHEN in Germany, recently. 1 took the opportunity of visiting the various Daimler-Benz production plants in Gaggenau, Mannheim and Sindellingen where Mercedes-Benz commercial vehicles are produced. The West German manufacturers take on a new significance, of course, in this country if Britain joins the Common Market, I was most impressed with the modern production methods in these various plants, and particularly the care and attention that go into the manufacture of all types of vehicle—despite which Mercedes-Benz products are the mest competitively priced to Western Germany.
The Sindelfingen plant is mainly concerned with car production and steel presswork, but a section of the extensive factory there is devoted to building L319 and L319D 1+-ton light commercials.
Heavies and .Uniniogs
At the Gaggenau plant, where 7,600 people are employed. Mercedes-Benz heavy models and Unimogs are produced, the daily production of he-tvies being about 40 in addition to 35,40 Unimogs. The heavies are assembled on a moving line, one of the many interesting features of which is the assembly jig employed at the start of the line for mounting the front and rear axles to the chassis frame, which arrives in the assembly shop with springs already fitted.
This has two movable beds on which the axles are positioned, following which the frame assembly is dropped on to the axles, U-bolts and nuts are applied by hand, and then electric torque wrenches mounted on the beds tighten all 16 nuts simultaneously to a predetermined degree.
At the Mannheim plant there are at present 11,600 employees, and 65 r4 goods vehicles of from to 6-ton capacity are assembled there daily, in addition to 20 c.k.d. kits and 10 fully integral passenger vehicles. There large Daimler-Benz foundry in Mannheim, employing 1,300 men and producing 2,000 tons of castings per month, the whole process being highly mechanized except in the case of the molybdenum-iron-alloy cylinder-head castings, production of which has only started recently. The use of this alloy, which is fairly expensive to produce, has been adopted to prevent the cylinder-head cracking which had been causing some trouble over the past few years.
In addition to the goods and passenger vehicles and castings, some 2,800 diesel engines are produced each month by the Mannheim factory, both for use in Mercedes-Benz vehicles and for sale as separate units. These engines range in output from 100 to 126 b.h,p., and extensive use is made of transfer machinery in the cylinder-block and head machining processes.
While at Gaggenau, I spoke to Dr. Jahr, technical director of the Gaggenau plant, who explained that Daimler-Benz commercial-vehicle production had been made flexible to allow for customers' special needs, even to the extent of offering different axle tracks for the same vehicles to meet the varying legal requirements of countries to which their products are
exported. Several different types of braking-system have had to be adopted also for the same reason.
Questioned about future plans, Dr. Jahr said that, whilst they would even
tually test experimental air-suspension installations on their goads vehicles, he did not necessarily feel that air springs would be the best alternative to current laminated-steel-spring systems, which, he said, "were not all that bad, after all."
Similarly, he did not t there was any need to deN independent front7susper layout for goods vehicles pointed out, however, tha position was different regard to buses and coa. cer t a i n Mercedes examples of which haw suspension and indeper front suspension, but explained this by saying that large-capacity vehicles were desi more like cars.
Dr. Jahr revealed that Daimlerhad carried out fairly extensive with disc brakes on their h vehicles, but these had not pr satisfactory because of heat-dissip difficulties. He felt that, whilst ii future disc brakes might be appli. to light commercials, they are uni to be a satisfactorypropositior heavies and that in any cast German vehicles had exhaust b as standard equipment to relievi drum brakes of excessive heat bui on tong descents with a full load In the same light, Dr. Jahr 4 not see the advent of automatic 1 missions on heavy goods vel because he considered them too 1 and too complicated. Buses, del vans and cars, yes, but not on designs of above about 3-ton cap Turbochargers Regarding turbocharging, Dai Benz have already used a turboch an a 100-b.h.p. diesel, this install giving a power-output increas about 26 per cent. Dr. Jahr saic at present there was DO neet Daimler-Benz to apply turbocha to their larger engines as their malty aspirated 200 b.h.p. diesel sufficient power to meet the ret ments, of the German regul; which demand 6 b.h.p. per ton weight (the German gross-weight is 32 tons).
However, he considered that was a pretty good chance tha German regulations might be am. to demand 8 or even 10 b.h.p. pi gross weight, which would necei the use of considerably more pol engines. Under these circurnst he considered the use of turboch: would be justified.