自移式液压支架外文文献翻译、中英文翻译

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英文原文（见参考文献[19].P157）

SELF-ADVANCING HYDRAULIC POWERED SUPPORTS

Modern longwall mining employs hydraulic powered supports at the face area.

The support not only holds up the roof, pushes the face chain conveyor, and advances

itself, but also provides a safe environment for all associated mining activities.

Therefore its successful selection and application are the prerequisite for successful

longwall mining. Furthermore, due to the large number of units required, the capital

invested for the powered support usually accounts for more than half of the initial

capital for a longwall face. Therefore both from technical and economic points of

view, the powered support is a very important piece of equipment in a longwall face.

The application of modern powered supports can be traced back to the early

1950’s. Since then, following its adoption in every part of the world, there have been

countless models designed and manufactured in various countries. But unfortunately,

there still is no uniform system of classification.

A simplified classification is used in this section. Since a powered support

consists of four major components (I. e., canopy, caving shield, hydraulic legs or

props, and base plate), the ways by which they are interrelated are used for

classification. In this respect , two factors are most important : (1) presence or absence

of a caving shield - if a caving shield is included , the support is a “ shield ” type ,

otherwise , a frame or a chock ; (2) number and type of arranging the hydraulic legs -

since support capacity is generally proportional to the number of hydraulic legs , it is

important to specify the number of hydraulic legs that a support has . Furthermore, the

way the hydraulic legs are installed is important; for example, a vertical installation

between the base and the canopy has the highest efficiency of application whereas an

inclined installation between the base and the caving shield has the least efficiency in

supporting the roof.

Based on this concept, there are four types of powered support, that is, the frame,

chock, shield, and chock shield, in order of evolution of their development. However,

it must be noted that the trend of development in each type is such that it becomes less

distinguishable in terms of application.

The four types of roof supports can be obtained for either longwall retreating or

advancing systems, and they are available in standard, one-web-back, and immediate

forward support (IFS) versions.

With the standard system, the winning machine takes a cut or a slice, and the

armored face conveyor is pushed over by the hydraulic rams that are fixed to the

support units. The support units then are advanced sequentially to the conveyor. With

the one-web-back system, a support is set back from the conveyor by a device that

automatically keeps the leading edge of the support at a fixed distance from the

conveyor .This allows easy access through the face and employs the standard method

of advancing; I. e., pushing the conveyor first, and then advancing the support.

With the IFS system , the support unit is advanced to the conveyor immediately

after the cutting machine has passed , and the forward canopy of the support unit is

long enough to support both the recently and newly exposed roof sections . After the

supports have been advanced, the conveyor is pushed over.

FRAME

The frame support is an extension of the single hydraulic props conventionally

used underground. Thus it is the first type developed in modern self-advancing

hydraulic powered supports .It involves setting up two hydraulic props or legs

vertically in tandem that are connected at the top by a single or two segmented

canopies .The two segmented canopies can be hinge-jointed at any point between the

legs or in front of the front leg .The base of the two hydraulic legs may be a circular

steel shoe welded at bottom of each leg or a solid base connecting both legs (Fig. 8.8).

Generally, a frame support consists of two or three sets of hydraulic legs. The set

moving first is the secondary set; the set moving later is the primary set .There is a

double-acting ram installed between each set. The piston of the ram is connected to

the secondary set and the cylinder to the primary set. During support advance (Fig. 8.

9), the primary set is set against the roof while the secondary set is lowered and

pushed forward by the piston. Having reached the new position, the secondary set is

set against the roof while the primary set is lowered and pulled forward by the

cylinder. The distance of each advance ranges from 20 to 36 in. (0.50~0.91m).

Fig. 8.8 Frame support

A-primary set b-secondary set

A B C

Fig. 8.9 Method of advancing the frame support

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摘要：

翻译部分英文原文（见参考文献[19].P157）SELF-ADVANCINGHYDRAULICPOWEREDSUPPORTSModernlongwallminingemployshydraulicpoweredsupportsatthefacearea.Thesupportnotonlyholdsuptheroof,pushesthefacechainconveyor,andadvancesitself,butalsoprovidesasafeenvironmentforallassociatedminingactivities.Thereforeitssuccessfulselectiona...

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