SU1234648A1 - Hydraulic prop - Google Patents

Description

The invention relates to mining machines and can be used in the hydraulic equipment of the sections of the mechanized roof supports.

The purpose of the invention is to protect the rack from dynamic loads and unloading when clamped by rock pressure in the lower position / stem.

The drawing shows the scheme of the proposed rack.

The hydraulic strut contains a cylinder 1 with a bottom and an inner diameter d, a hollow rod 2 with a diameter dj and a bore diameter d in which plunger 3 is placed, sealed with rings 4. Plunger 3 is supported through a sealing gasket 5 into the bottom of an additional piston 6 having openings 7 , connecting the internal cavity of the additional piston 6 with a diameter of d4 to the piston cavity of the rack. The additional piston 6 is sealed by cuffs 8 and can move within the height h of the internal cavity along the piston 9: stem 2, sealed by a ring 10 and a lateral seal 11. The additional piston 6 is held on the piston 9 of the stem 2 by semirings and retaining ring 12. The rod end cavity is in communication with the hydraulic unit 13, channel 14, and the piston channel 15 - with a safety valve 16 adjusted for operating pressure, and channel 17 with a safety valve 18 adjusted for emergency pressure, and a hydraulic lock 19. To the hydraulic unit 13 are attached along arches 20 and 2b. Compressed gas is injected into the bore of stem 2 through channel 22, normally closed.

Hydraulic rack works as follows.

When connecting the pressure line 20 through the hydraulic lock 19 with the channel 17, the working fluid enters the piston cavity and pushes the stand. After the working pressure is created in the piston cavity with the drawdown of the rack, excess fluid is discharged through channel 15 and safety valve 16. In the lower position, the additional piston 6 is held by plunger 3 under gas pressure in the rod end. This position of the additional piston is provided provided that if P is the working pressure in the piston cavity of the rack;

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P is the gas pressure in the piston, and -Pj, then the inequality must be ensured:

/ yj rt l

Pi () 4 g and “and

.р ZjS j ;: -d

With dynamic loads, the pressure in the piston cavity, the strut increases by P and, when

(P, + yP,) (). the additional piston and plunger will move upwards, while the gas in the rod end is additionally compressed, and the rod’s drawdown is ensured by this at a constant volume of fluid in the piston cavity of the rack. After the safety valve 16 is operated, the pressure in the piston cavity will decrease to PI and the additional piston will return to the lower position.

When the stand subsides. The channel 15 is tightly overlapped by the additional piston and the pressure in the cavity of the additional piston may increase to an emergency one, after which the safety valve 18, which is adjusted to a pressure slightly less destructive, will operate, and therefore the drawdown of the rack will decrease significantly or stop completely.

For additional slump of the stand, which was planted by the Rigidly before moving the section, the channel 1.4 is connected to the head, and the channel 17 - with the drain and the piston 9, overcoming the resistance of the plunger, can be lowered by the amount b, slid along the additional piston.

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- If the pressure of the oil station is P, then this will happen when observing the inequality

), g After moving the section channel

14 is connected to the drain, and the channel 17 is to the pressure and the stand is moved apart, with the piston pressure returning the additional piston to the lower position,

During normal operation, the additional piston does not move, and when adjusting the safety valve 18 to the same operating pressure as valve 16, the rack will have an additional reserve of travel B and be protected from dynamic loads,

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Compiled by V. Ponomarev Editor M. Petrova Tehred O. Gortvay. Proofreader A. T sko

Order 2964/42 Edition 470Subscription

VGOSHPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

ProductionTVeins-printing-enterprise, Uzhgorod, st. Design,

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Claims (1)

A HYDRAULIC RACK, comprising a cylinder with a bottom, a hollow rod, in which a movable plunger is installed, which forms a closed cavity, a piston with a rod, a rack-mounted hydraulic unit with a safety valve configured for operating pressure and a connected channel made in the cylinder wall, with a piston cavity of a hydraulic rack, characterized the fact that, in order to protect the rack from dynamic loads and unloading when clamped by rock pressure in the lower position of the rod, the piston of the rack is equipped with an additional piston, made in the form of a glass with holes in the end part, mounted movably on the piston of the rack and interacting with the inner end with the end face of the plunger and the outer cylindrical surface with the cylinder of the rack, while the valve body is equipped with an emergency safety valve connected by an additional channel to the piston cavity of the hydraulic stand, made in the form of a cylinder, and a closed cavity the rod is filled with gas, and an additional piston in the lower position blocks the channel made in the cylinder wall. SU 1234648 A1 1 1234648