FR2474112A1 - LONG-HOLE CYLINDER THAT CAN SERVE MINE ROOF SUPPORT - Google Patents

Abstract

CYLINDER CAPABLE OF DEPLOYING OVER A GREAT LENGTH. IT INCLUDES A CYLINDER 12 CAPABLE OF SLIDING ON A PISTON 10 AND CAN BE PUT IN THE EXTENSION POSITION AND UNDER PRESSURE WITH WATER OR OTHER FLUIDS THROUGH A CHECK VALVE MOUNTED IN THE HEAD 13 FROM THE CYLINDER, A PREVIOUSLY SET PRESSURE DISCHARGE DEVICE IS MOUNTED ON THE CYLINDER HEAD AND DISCHARGES FLUID EACH TIME THE PRESSURE IN THIS CYLINDER AND ON THE PISTON EXCEEDS THE PREVIOUSLY SET LEVEL, A SECOND DEVICE DELETS WITH A CONTROL ELEMENT 31, 34 ALLOWING TO ELIMINATE THE PRESSURE IN THE CYLINDER AND TO RELEASE THE CYLINDER BY REMOTE CONTROL. APPLICATION TO MINE ROOF SUPPORT CYLINDERS.

Description

The invention relates to long-wall cylinders and more

  particularly to hydraulic cylinders of this kind which drop and yield under a predetermined pressure while maintaining this predetermined pressure continuously at the time they yield. It has been suggested previously to replace in the mines wooden wedges and the like by long-walled cylinders. This type of jacks raised different problems in the prior art. Many of them were expensive and had a complicated structure. They were usually heavy and required an oil pump for their placement. Moreover, they were ill-adapted to yield, bend or warp instead of giving in and he was

  difficult to recover for reuse.

  The cylinder with long partition, able to yield, according to the invention, is lightweight, its structure is very simple, it operates under the effect of a pressure of water or other fluid, it gives in to a pressure predetermined while continuously maintaining this pressure and it can be

  easily recovered and reused.

  The long-wall jack according to the invention comprises a piston comprising a base at one end, a cylinder surrounding this piston from the other end, this cylinder comprising a head of the opposite side to that of the base, said head comprising an intake equipped with a retaining device and communicating with the inside of the cylinder above the surface of the piston, said head further comprising a first evacuation which communicates

  with the inside of the cylinder above the piston, a

  pre-set pressure relief device being mounted in said evacuation and being adapted to discharge fluid from the cylinder each time the pressure prevailing therein

  exceeds said preset pressure, an elongated lever sensi-

  parallel to the axis of the cylinder, being articulated at one end on said head and having at the other end a hole into which a cable may be passed, the head comprising a second discharge in which is mounted a valve and a connection between the latter and the first end

2.2474112

  said lever being intended to open the valve when the lever undergoes a pivoting movement placing it transversely to the axis of the cylinder. The valve preferably consists of a ball subjected to the force of a spring and the connection is a rod movable in a channel of said head so that one of its ends is applied against the ball and the other against a control cam being at the

  first mentioned end of the lever. Admission to

  The retaining device is preferably of the "Alemiten" type, the base located at the end of the piston is preferably slightly hemispherical, and the cylinder is preferably under pressure.

  with water or emulsion in water.

  The invention will be described in more detail with reference to the accompanying drawing by way of non-limiting example and in which: - Figure 1 is an axial section of the long-wall cylinder according to the invention; - Figure 2 is a plan view of the cylinder head of Figure 1; - Figure 3 is a section along the line III-III of Figure 2; - Figure 4 is a section along the line IV-IV of Figure 2; and - Figure 5 is a partial elevation of the cylinder of the

figure 1.

  The jack shown comprises a piston 10

  having a base 11 at one end. An outer cylinder

  12 end surrounds the piston 10 above the base 11 and supports a head 13 at the end facing away from the base 11. The end 14 of the cylinder 12 located on the opposite side to that of the head 13 supports a ring 15 which closes the end and in which is housed a scraper ring 16 which slides on the piston 10. A stop ring 17 is placed on the piston away from the base 11 so as to limit the displacement relative to the cylinder 12. The end 10a of the piston 10 which is on the side opposite to that of the base 11 supports an annular seal 18, a bearing ring 19 and a lining 20 which bear 2.

2.2474112

  against the surface of the cylinder 12 and provide tight mounting of the piston in the latter. The head 13 of the cylinder comprises an intake channel 21 which communicates the outer side of this head with the inside of the cylinder 12, above the piston 10. A fitting 22 with a check valve of the "Alemite" type is mounted in the intake channel to allow the introduction of hydraulic fluid from the outside into the cylinder 12, above the piston 10. A first discharge channel 23 is formed in the head 13, away from the duct. intake 21, approximately parallel to the latter, and communicates the interior of the cylinder 12,

  above the piston 10, with the outside. A decompression valve

  pressure 24, which is mounted in the first discharge channel, is preset to the pressure at which it is necessary for the cylinder to yield, for example under a load of 22.5 tons. A second discharge channel 25 made in the head 13 communicates the inside of the cylinder 12, above the piston 10, with the outside of this head via a check valve 26, mounted in a transverse channel 26a, and a deflector 27. A manually operated valve 28, which is mounted in the channel 25, is constituted by a ball 29 loaded by a spring which applies it against a seat 30 situated at the connection of the channels 25 and 26a. A lever 31 is articulated at one end 31a inside a yoke 32 secured to the head 13 and normally is placed parallel to the cylinder 12. The other end 31b of the lever comprises a transverse bar 31c intended to be drawn by hand or on which can be fixed a rope or cable (not shown) to exert traction. The end 31a of the lever 31 forms a cam surface 34 which bears against a pin 35 housed in a channel 36 at the alignment of the ball 29. When the lever 31 is pulled outwards and rotates around its pivot to be placed in a position perpendicular to the cylinder 12, the cam surface 34 pushes the pin 35 which pushes the ball 29 against the force of the

  spring 29a thus allowing the fluid of the

cylinder 12.

3.

2.2474112

  When the jack of the invention has been placed in place, it is placed in position of extension and under pressure by the introduction of pressurized water by the connection 22 of type NAlemite 'so as to fill with water. space included inside the cylinder 12 between the head 13 and the piston 10 in order to cause the relative movement of the cylinder 12 and the piston 10 and to put the supports 13a of the head 13 in abutment

  against the roof of the mine to be supported.

  Water or an emulsion in the water is introduced into the cylinder until the cylinder is put to the desired pressure. When the pressure that the roof exerts on the cylinder exceeds the preselected decompression value corresponding for example to a load of 22.5 tons, the cylinder automatically leaves the water or emulsion into the water through the first channel of the cylinder. 23 and the decompression valve 24 so as to oppose a continuous resistance under the preselected pressure of decompression, the cylinder not bending and not deforming or not being

  destroyed as were many cylinders of the prior art.

  When it is necessary to remove the jack and remove it, it is necessary to pull on the transverse bar 31c or to attach a rope or a cable around this bar passing in the lever 31 and a worker exerting a traction on the cable by putting himself in position of safety raises the lever 31 to the position in which it is perpendicular to the cylinder 12 with the result that the cam surface 34 pushes the pin 35 against the ball 29 by moving away from its seat and letting escape water or an emulsion in the water of the interior of the cylinder 12 through the channels 25 and 26a, the check valve 26 and the deflector 27. As a result, the cylinder

  12 slides on the piston 10 away from the roof supported.

  When the pull on the rope or cable continues, the jack falls to the side and can be pulled by the worker. It goes without saying that the invention has only been described by way of example and that various modifications can be made to it.

  brought without leaving his domain.

4.

2.2474112

Claims (7)

  1. - Long-wall jack, characterized in that it comprises a piston (10) having at one end a base (11) and wrapped at the other end by a cylinder (12) sliding on it and comprising the end turned away from said base a head (13) in which is   realized an admission (21) on which is mounted a   retaining device (22) and which communicates with the inside of the cylinder, above the piston, a first discharge (23) formed in said head communicating with the inside of said cylinder, above the piston, a discharge device (24). ) under preset pressure being mounted in said discharge (23) so as to discharge fluid from said cylinder each time the pressure prevailing therein exceeds said pressure previously. set, a second evacuation (25) made in said head (13) communicating with the inside of the cylinder, above the piston, a pressure lowering valve (28) being mounted in said second evacuation and a control device (31) mounted on said cylinder engaged with said pressure lowering valve (28) such that traction exerted on said control device opens said pressure lowering valve which is mounted in the second discharge (25). ) in order to evacuate fluid from the cylinder and to allow the cylinder to slide on the piston.   2. - Jack with long partition according to the claim   1, characterized in that said control device consists of a lever (31) pivotally mounted at one end (31a) on said head (13) and normally occupying a position in which it is parallel to the axis of the cylinder (12). ), the other end (31b) of the lever having a member (31c) on which a rope or a pulling rope can be attached, a cam (34) being formed on the first mentioned end of the lever and a cam follower ( 35) mounted in said head (13) for engagement with said pressure lowering valve (28), said cam surface (34) acting on the follower to open said valve when the lever is moved. 5. Swiveling from the normal position to a position in which   it is transverse to the axis of the cylinder.   3. - Jack with long partition according to one of the   1 and 2, characterized in that said base (11) of the piston comprises a hemispherical bottom surface. 4. - Long-wall jack according to any one   Claims 1 to 3, characterized in that said   retainer consists of an intake channel (21) at the outer end of which is mounted a coupling (22) of the type "Alemite".   5. - Long-wall cylinder according to one of   Claims 1 and 2, characterized in that the device for   pre-set pressure discharge consists of a valve or a relief valve (24) subjected to the force of a spring.   6. - Jack with long partition according to the claim   5, characterized in that the valve or the relief valve (24) is set to cause the discharge when undergoing a thrust corresponding to a load. about 22.5 tonnes.   7. - Long-wall cylinder according to one of   Claims 1 and 2, characterized in that said head (13)   has a deflector (27) mounted on the second outlet (25) to deflect the fluid discharged from the discharge approximately parallel to the axis of the   cylinder and towards the piston base. 6.