‘Building mashines’ Text 1. Earth-Moving Machinery

Match the following words and translations.

The annual amount of mechanized earth digging operations comes up to thousands of millions, of cubic meters. It requires the employment of a great plant of powerful earth-moving machines, the excavators being the most important of them.

It is not possible to start on a construction job without a good deal of preliminary leveling the site. To carry out this work one must employ the earth-moving equipment.

Site preparation and excavation are the most fully mechanized of all the operations in building construction. Most excavating machinery is heavy and slow-moving and must be carried from site to site on special transporters. It is clear that the use of expensive mechanical plant requires careful planning and efficient site organization if full advantage is to be taken of its high rate of production.

Plant for site preparation and excavation can be divided into four classes. First, machines which plane off a thin layer of soil and push it in front of them. Second, machines which plane off a thin layer of soil, at the same time picking it up and carrying it where required. Third, machines which: dig out soil by some form of a bucket, and load it for transportation into separate vehicles. Forth, machines designed specially for trenching by means of a number of buckets mounted either on a continuous chain or on a wheel.

In the first class are bulldozers of different types. A bulldozer represents by itself an earth-moving machine which carries out its work with the aid of a blade mounted on a tractor of either crawler or wheel type.

A scraper, which belongs to the second class of earth-moving machines, is simply a large box with an open mouth, dragged along the surface of the ground until it is full. It has a cutting edge that digs. There is a considerable variety of the scrapers, from small units to huge ones made to accommodate 30 cubic yards of soil and to absorb the power of two tractors while at work.

Revolving shovels, which belong to the third-class of earth-moving machines, made their first appearance in 1835 in the form of a part-swing shovel mounted on railroad tracks. It was powered by steam, it was slow and clumsy, but it did the work. Into Great Britain they were introduced from America in 1887 to work on the Manchester Ship Canal. Trey were a source of wonderment to the people of that part of the country and trips were organized to provide a view of the ‘American Devils’ as they were popularly called.