Historical Errors in Equipment Design

Tom Berry, Contributing Editor | July 5, 2018
Euclid's first, utterly unique motor scraper loads its rear bowl.

Things do not always work out as anticipated, and errors can creep into just about anything. There have been several errors in judgment in the design and manufacture of construction equipment. Let’s look at some examples.  

Above: With a partial load visible in its front bowl, Euclid's first, utterly unique motor scraper loads its rear bowl. The maze of hoses hints at the full hydraulic control.

First, the it-seemed-like-a-good-idea-at-the-time error. Euclid’s first motor scraper was wildly unconventional, a 6½-cubic yard, two-bowl affair on a powered front and rear steering axle, with one bowl ahead of the front axle and the other between the two axles. The operator sat above the rear bowl, with the engine behind. A test bed was built in 1939, and the twin-bowl scraper was recognized as an utter failure.

The next year, Euclid introduced the MDT and MGT series motor scrapers. At first glance, they looked very much like a typical, over-hung design with a single-axle tractor. But appearances can be deceiving. Whereas all other over-hung scrapers steered at the gooseneck between the tractor and scraper, the gooseneck on these machines was rigid, and steering was accomplished with the scraper axle. Only a handful of these overly complex machines, including one bottom dump, were built.

Then there is the never-mind-the-bugs-roll-it-out-now error. In 1947, International Harvester introduced the TD24. It was billed as the world’s most powerful crawler tractor and the first to use two-speed planetary steering. The TD24 was marketed as being faster, more maneuverable, more stable on slopes, and a more powerful puller than its competitors. In the haste to bring the machine to market in answer to the Allis-Chalmers HD19, however, IH overlooked critical flaws in the TD24’s drive train and steering system, while also failing to adequately test the new designs. By the end of 1948, all TD24s in the field were recalled and scrapped, because the flaws were beyond repair. Fortunately, the redesigned TD24 earned respect and good sales starting in 1949.

Finally, the it’s-always-worked-so-why-change?” error. In 1885, J.D. Adams revolutionized grader design by inventing the leaning wheel, which allowed the weight of the grader to rest more heavily on the blade so as to keep the blade from pushing away from its load, while also allowing the machine to work more productively in ditches and on slopes.

But 40 years later, C.D. Edwards Manufacturing rejected the concept. Edwards claimed that leaning wheels were needed only to correct for an imbalanced design and that they added up to wasted money for extra parts and maintenance. The “perfect balance” of the Edwards’ rigid-wheel graders, said the company, held these machines against the load. Edwards went so far as to say that the perfectly balanced straight-wheel grader was “the greatest development and stride forward over the adjustable wheel.” Almost a century later, Adams’ principle lives on.

The Historical Construction Equipment Association (HCEA) is a 501(c)3 non-profit organization dedicated to preserving the history of the construction, dredging and surface-mining equipment industries. With more than 4,000 members in 25 countries, HCEA’s activities include publication of a quarterly educational magazine, Equipment Echoes, from which this article is adapted; operation of the National Construction Equipment Museum and archives in Bowling Green, Ohio; and hosting an annual working exhibition of restored construction equipment. HCEA’s 2018 show will be August 24-26 at the Le Sueur Pioneer Power Show in Le Surer, Minn. Individual memberships within the U.S. and Canada are $35 for one year, $66.95 for two years, and $99.95 for three years. Membership elsewhere is $45 U.S. per year HCEA seeks to develop relationships in the equipment manufacturing industry and offers a college scholarship for engineering and construction-management students. Information is available at www.hcea.net, by calling 419.352.5616, or e-mailing info@hcea.net.

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