2.1. Ways of unloading a scoop

Three main ways of an unloading are applied: free (fig.7, a, f), semi-forced (fig. 7, c, d), and forced (fig. 7, b, e).

During the free way of unloading the soil can be unloaded for­ward or back. For this purpose, the scoop is turned around a point lying near to the center of gravity of a scoop with the soil. This way is suitable for activity in free-flowing soils.

It provides enough fine adjustment of the depth of a discharged layer. In such a way, it is possible to execute an unloading downhill (at a single-axle design of a scraper). The scoops with a free unloading are applied for scrapers of very small capacity for by-works.

b

Fig. 7. The schemes of the main types of scoops and ways of their unloading:

a - grab (clamshell) type with a tipping over unloading; b - with a forced unloading by moving out the rear wall; c - with a semi-forced unloading through a knife by the turning the bottom; d - with a forced unloading through the bottom (floor); e - telescopic with a forced unloading by moving out the rear wall; f - with a tipping over unloading back (for a single-axle scraper)

At a semi-forced way the soil is unloaded by turning the bottom or the rear wall together with the bottom concerning the lateral walls of a scoop and thus is partly pushed out at this particular movement. The disadvantage of this way is although it is better emptying than at a free unloading, nevertheless the emptying of a scoop is inexact, especially if there are sticky and humidified soils.

At a forced way the soil is pushed out by sliding the wall horizon­tally migrating on the rollers in guides. This way provides the full unloading of any soils. Its disadvantage is the large efforts and powers which are indispensable for the movement of the rear wall.

Score: 10

Ex.23. Answer the following questions on the text:

1. How many ways of unloading a scoop do you know? Name them.

2. What is the correlation between the type of soil and the way of unloading a scoop?

3. How does the scoop function depending on the way of its unloading?

Score: 3

Ex.24. Look at Fig.7., name a, b, c, d, e, f and describe the figure.

Score: 5

Total score: 230 points.

Список літератури:

1. Баладинський В.Л., Лівінський О.М., Хмара Л.А. Будівельна техніка. - К.: Либідь, 2001. - 368 с.

2. Гальперин М.И., Домбровский Н.Г. Строительные машины. - М.: Машиностроение, 1980. - 344 с.

3. Трофимов А.П., Холодов И.Я. Специальные транспортные машины в строительстве. - К.: Будівельник, 1983. - 152 с.

4. Фиделев А.С., Чубук Ю.Ф. Строительные машины. - К.: Вища школа, 1979. -335 с.

5. Ятель Г.П., Князевський Б.М., Кузик Ф.К. Англійська мова. – Львів: “Світ”, 1990. - 314 с.

6. Learn to speak on your speciality: Учеб. Пособие / A. H. Акмалдинова. - К.: УМК ВО, 1992. - 212 с.

7. The Modern Pictorial English Dictionary/ М.Автайкин, И.Чувелев. -M.: ЛЕО, 1993.-352 с.

61