This story is not an exhaustive history of Hitachi’s excavators, but more of an overview of how things progressed from their first steps after WW2, through to the mid-1970s when things really began to take off into what is now a huge market for Hitachi hydraulic excavators. By Richard Campbell.
What was to become the Hitachi Construction Machinery Company was originally founded in 1910.
The company was mainly selling domestically, manufacturing smaller pieces of construction equipment, and even an electrically operated face shovel (introduced 1939) before WW2 put an end to domestic production and all company output became of a military nature. Following the War, Japan had been devastated by mass area bombing and it was quite remarkable that by 1949 the Hitachi company had begun to produce its first post-war excavator – the model U05.
While not a runaway success, this machine led to the model U06 in 1950 which was exported to several countries, and then in 1958, the model U106A cable operated excavator was released.
The U106A was a successful, conventional, cable-controlled excavator with a one cubic yard bucket (in face shovel mode), powered by a 98 flywheel horsepower, four cylinder Hitachi B40 diesel engine.
The machine featured a ‘universal’ front, meaning it could be set up in several different configurations depending on customer preference: face shovel, backhoe, dragline, earth drill, crane, piledriver, etc.
It was also the first excavator in the world to have a torque converter between the engine and working winches to help cut down on shock loading. Examples of the U106 were imported into New Zealand by agent CablePrice Corporation (still the distributor), making the U106 the first Japanese-manufactured excavator to arrive in this country.
However, by the early 1960s, the writing was on the wall for cable operated excavators.
It took several years to train a cable excavator operator to a good level of proficiency, and something more efficient was now called for.
Hitachi engineers had been studiously working away to develop something new and, in 1965, released the model UH03, the first hydraulically operated excavator to be manufactured in Japan.
Looking remarkably like the excavators of today (although a little more austere), the UH03 weighed just over eight tons, wielded a 0.35 cubic metre bucket, and was powered by an Isuzu 4DA220 four-cylinder diesel engine which produced around 50 flywheel horsepower.
Easy to operate, even for a novice, the UH03 was an immediate success, both domestically and as an export earner.
Following the release of the model UH03, it did not take Hitachi long to realise that hydraulic operation was indeed the way to go, and so the company embarked upon an intensive manufacturing campaign to produce a wider range of these machines. While the UH03 did not enjoy a particularly long production run, its successors most certainly did.
Next to appear was the slightly smaller (6.2 tonne) model UH02 which had a 0.3 cubic metre bucket and was powered by a 48 horsepower, four-cylinder Isuzu C330 diesel.
The UH02 met immediate success and was exported worldwide. Like the UH03, the UH02 did not remain in production for very many years and was replaced by the model UH031 around 1982.
One machine deserving special mention was the model UH04 that first appeared in the mid-1970s and sold very well, establishing a good export market.
An extremely popular little unit, the 12-tonne UH04 had a 0.5 cubic metre bucket and was available in several different versions (including a swamp model with a wider track frame and extended grousers). Usual power for the UH04 was an 80 horsepower Isuzu 6BB1 diesel.
Other significant machines for the company were the model UH06 (introduced in 1968), its successor the model UH07 (introduced in 1973) and model UH09 that appeared around the same time.
The UH06 weighed just over 12 tonnes and was powered by an Isuzu 6BDI six-cylinder diesel. Standard bucket was 0.5 cubic metre bucket.
The machine was reasonably popular and underwent several series upgrades including UH06D and UH06DT variants before it was replaced by the UH07.
The UH07 was a huge success, and, like its predecessor the UH06, underwent several upgrades during its production life including UH07-3 and UH07-5 versions. Powered by a 100 horsepower Hino DS50 sixcylinder diesel, usual standard bucket size was one cubic metre.
UH07s saw extensive use here as more and more users switched from cable excavators to hydraulically operated machines.
Also using the Hino DS50 engine (at a slightly higher 125 horsepower rating) was the UH07’s larger stablemate, the model UH09.
Designed for bulk excavation across a wide range of scenarios, the UH09 tipped the scales at 22 tonnes and was normally equipped with a 1.1 cubic metre bucket.
UH09s also saw widespread use in New Zealand.
In 1973 the largest Hitachi excavator built up to that time, the model UH20, was launched. It was designed from the outset as a hydraulic face shovel for quarry and mine use, and it was a real biggie for the day, weighing some 53 tonnes.
Featuring a parallel crowding mechanism, the UH20’s bucket could scoop up 4.5 cubic metres in a pass.
The machine was powered by two Isuzu E120 s-cylinder engines with a combined output of 300 horsepower. While this may not sound much compared to some of today’s machines, the UH20 was a big deal in 1973!
Hitachi also built a small number of backhoe models of the UH20, but these were never as popular as the face shovel variant.
Near the end of the 1970s, Hitachi produced an up-scaled version of the UH20 designated the UH30. Again, targeting the quarry and mining customer, the UH30 excavator featured the same twin Isuzu engine setup of the UH20 (but with more horsepower) and weighed 73 tonnes. Usual face shovel bucket was a 12 cubic metre clamshell type.
Not a great many of this machine were manufactured by Hitachi.
This ends our look at the early development of the Hitachi hydraulic excavator. I will be researching later developments and will publish a continuation of this story in a future issue of Q&M.
For the model collector
There are several models of early, pre-1980 Hitachi excavators available including the UH03, UH04 and the UH20. Unfortunately they are poorly detailed and not to a constant scale as most of these unusual sized items being to 1/64 or 1/70 scale which does not always fit comfortably within a 1:50 ‘fleet’. Try Buffalo Road Imports in the USA to see its extensive collection of older (and newer) Hitachi excavators.
