Advanceable Shield Support

Abstract

An advanceable shield support apparatus suitable for use in long-wall mine workings using peeling techniques. The apparatus comprises a bottom sill, an overhead fall shield which is articulated to the goaf side of the bottom sill. The fall shield is supported by hydraulic props and, at its seam-facing front end, is coupled to a roof cap. The roof cap is longitudinally displaceable relative to the overhead fall shield by means of a sliding guide mechanism arranged on the top of a cradle-like bed. The bed is articulatedly mounted at the leading end of the overhead fall shield.

Description

This invention relates to an advanceable shield support unit for use in mining, preferably, but not exclusively, for use in long-wall workings using peeling techniques with a bottom sill and an overhead fall shield articulated to the goaf side of the bottom sill and supported by hydraulic props and which at its seam-facing front end is coupled with a roof cap. Such support units are known but do not always meet the requirements posed in view of the circumstances described in what follows.

With long-wall supporting, falls arise in general before working in the lower region of the coal seam is complete and the shield support units can be advanced. With the known shield support units, it is not possible to support substantial portions of the roof before the units are moved forward. An additional exposed roof area arises because the leading edge of the roof shield moves away during its upward pivoting relative to the roof as a result of the pivoting radius which obtains. To safeguard the parts of the roof which cannot be supported by the shield until the latter is moved forward, the only solutions applied hitherto have been the use of temporary props. However, the use of such temporary props is uneconomic and moreover does not give an entirely stable support.

In addition, in workings using peeling techniques, further problems arise in respect of the supporting of the roof. Only small relative advancing is used for each plough cut, so that the roof areas exposed as a result are generally small. Moving the shield support of the type mentioned above forward in each case at once in correspondence with the small cuts would have to take place in very small steps, would lead to an exceptionally disadvantageous unsettling of the roof and would no longer ensure safe control of the rock formation. If, by contrast, the moving is performed only after several cutting steps, then each cut exposes a considerable roof area that is not supported for considerable periods of time, whereby once more temporary shoring necessary until the shield supports are advanced.

An aim of this invention is to seek to provide a shield support unit of the type mentioned above which avoids or substantially reduces the above mentioned drawbacks, i.e., in which the supporting of a temporarily exposed roof area of considerable magnitude is effected without temporary auxiliary solutions but is carried out solely by the shield support unit of the invention.

According to the invention, there is provided an advanceable shield support apparatus suitable for use in long-wall mine workings using peeling techniques, comprising a bottom sill, an overhead fall shield which is articulated to the goaf side of the bottom sill, is supported by hydraulic props and, at its seam-facing front end, is coupled to a roof cap, the roof cap being longitudinally displaceable relative to the overhead fall shield along a sliding guide mechanism arranged on the top of a cradle-like bed which is articulatedly mounted at the leading end of the overhead fall shield.

With the support unit of this invention as described with reference to the attached drawings, see below, the entire cap supporting the roof may be advanced relative to the remaining parts of the unit in the direction of the seam; the total resistance of the support given to the individual shield always remains the same and remains intact. No additional supporting elements such as, for example, forepoling caps are necessary, because the supported roof area is generally of the same magnitude in all positions of the cap. The advancing of the roof cap relative to the overhead fall shield corresponding to the progress of the work can take place under full load. As a result, even partial or brief reduction of the area supporting the roof during working is avoided in an advantageous manner. The forces required for the advancing of the cap, which act substantially in the backward direction, are led into the overhead fall shield in advantageous fashion, with the shaping of the shield ensuring the advantageous concentration of forces to the bottom.

Preferably, the roof cap is displaceable along the cradle-like bed by means of an hydraulic cylinder. Either the hydraulic cylinder may be pivoted to one end of the roof cap, while its piston rod is pivoted to the cradle-like bed, or vice versa. The advancing of the roof cap may take place in several small steps or in one substantial step. As a result, displacement of the roof cap is possible at any support height substanntially independently of the angle between the roof and the overhead fall shield.

In a preferred embodiment of this invention, the bottom sill can be displaced relative to an abutment serving as a guide for the mining tool by means of an advancing means. Control of the hydraulic cylinders displacing the roof cap may be coupled with that of the advancing means moving the conveyor forward by the appropriate amount following each mining operation. The roof cap follows the progress of mining automatically and can always support the newly exposed roof areas. It is possible also to provide sensing elements which along or together with the conveyor moving means ensure an appropriate following-up displacement of the roof cap.

The drawing illustrates, by way of example only, a preferred embodiment of the invention.

FIG. 1 shows a side view of the preferred embodiment of a shield support unit, showing also a conveyor and a plough serving as a mining tool.

FIG. 2 shows a vertical section, on an enlarged scale, of the support unit of FIG. 1, in the region of the roof cap, and

FIG. 3 shows a vertical section taken on line III--III of FIG.. 2.

Referring to the drawing, a support unit 1 has a bottom size 2 with an upright end 3 on the goaf side to which an overhead fall shield 4 is articulated so as to be vertically pivotable. The shield 4 is angularly or arch shaped and includes an upright portion 4a and a generally horizontal shielding portion 4b. On its leading end 5, the overhead fall shield 4 carries a pivotably articulated, one piece roof cap 6. The support unit 1 is pivoted to a long-wall conveyor 8 via a backing means 7, which conveyor serves for guiding a plough-like mining tool 9. The bottom sill 2 and the portion 4b of the overhead fall shield 4 are supported by hydraulic props or rams 10.

The overhead fall shield 4 is bifurcated to have a double tongue at its leading end 5 facing the seam 11, with each tongue possessing an articulated bearing with a pivot pin 12. A cradle-like bed 13 is mounted on these two pins so as to be vertically pivotable. The bed 13 has a central portion 14 engaging in a recess 15 of the overhead fall shield 4 formed by the tongues 5.

On its top, the cradle-like bed 13 has a slidable guide mechanism 16' comprising guide sections 16 above its tongue 5 slidable in the longitudinal direction of the support unit 1, which are surrounded by corresponding, substantially U-shaped cut-away portions 17 of the one piece roof cap 6. The cap 6 is secured against lifting in the direction of the roof 18 by the provision of lateral strip-like extensions 19 cooperating with the guide sections 16.

Over its front region the cradle-like bed 13 carries a lug 20 to which is pivoted the piston rod 21 of a generally horizontally operable hydraulic cylinder or ram 22. The ram 22 is secured in position at its rearward end by means of a vertical joint pin 24 located in the rearward end of the roof cap 6.

In operation, the cylinder or ram 22 provides means for generally horizontally moving the roof cap 6 toward the seam 11 while the remainder of the support unit 1 including the bottom sill 2 remain stationary. Thus, as the roof cap 6 is moved toward the seam 11, the piston rod 21 is caused to be telescoped with respect to the remaining portion of the cylinder 22.

The hydraulic cylinder 22 serves for advancing the roof cap 6 in correspondence with the roof areas exposed by the mining tool. The total support resistance of the individual support units remains intact, because the area supported only by the cap does not change. As the roof cap is advanced under load, no unsettling of the roof will take place either. The support forces arising are taken up by the overhead fall shield extending approximately in the direction of the line of action of the forces.

Following full emerging of the roof cap, the props 10 are retracted somewhat and the roof cap is then driven backwards. Subsequently, the entire unit 1 is drawn toward the conveyor 8 by the backing means 7. This approaching can be synchronized with the return movement of the roof cap in such a way that the approaching and the return movement ensure simultaneously and at the same speed. As a result, a temporary safeguarding of the roof 18 over the region at greatest risk is ensured also during this workstage.

Claims

We claim:

1. Advanceable shield support apparatus, comprising a bottom sill, an overhead fall shield which is articulated to the goaf side of the bottom sill, hydraulic props supporting the overhead fall shield, a cradle-like bed supported by said props, a sliding guide mechanism being supported by said cradle-like bed, a roof cap coupled to the overhead fall shield at its seam-facing front end and supported by said sliding guide mechanism, the roof cap being longitudinally displaceable in its entirety on the cradle-like bed relative to the overhead fall shield leaving the shield free of engagement with the ceiling of the mine, the sliding guide mechanism being articulatedly supported by the overhead fall shield, and means for advancing the roof cap in its entirety relative to said cradle-like bed.

2. The apparatus of claim 1 where said roof cap comprises a one piece generally horizontally extending member suppported at its underside on said sliding guide mechanism.

3. Apparatus as claimed in claim 1, wherein the said means comprises a cylinder that is pivoted to the roof cap and its piston rod is pivoted to the cradle-like bed via a lug.

4. Apparatus as claimed in claim 3 wherein the cradle-like bed has a central portion engaging with a forked end section, formed by tongues, of the overhead fall shield.

5. Apparatus as claimed in claim 3, wherein the bottom sill is displaceable relative to an abutment serving as a guide for the mining tool by means of a movement-effecting device.

6. Apparatus as claimed in claim 1, wherein the cradle-like bed has a central portion engaging with a forked end section, formed by tongues, of the overhead fall shield.

7. Apparatus as claimed in claim 1, wherein the bottom sill is displaceable relative to an abutment serving as a guide for the mining tool by means of a movement-effecting device.

8. Apparatus as claimed in claim 1, wherein the cradle-like bed has a central portion engaging with a forked end section, formed by tongues, of the overhead fall shield.

9. Apparatus as claimed in claim 1, wherein the bottom sill is displaceable relative to an abutment serving as a guide for the mining tool by means of a movement-effecting device.

10. Advanceable shield support apparatus suitable for use in long-wall mine workings using peeling techniques, comprising a bottom sill, an overhead fall shield, means for pivotally supporting the overhead fall shield in overlying relation to the bottom sill, power operated ram means supporting the overhead fall shield for adjusting its vertical position and, a roof cap, an articulatedly mounted mechanism including a powered cylinder providing means for relatively moving the roof cap with respect to the bottom sill and forward into contact with the long-wall of the mine being worked upon, the overhead fall shield being coupled by coupling means to a roof cap at its seam-facing front end, a cradle-like bed, a sliding guide mechanism being carried on the cradle-like bed, and cylinder means for advancing the roof cap with the roof cap thereby being longitudinally displaceable relative to the overhead fall shield, the sliding guide mechanism being articulated mounted at the leading end of the overhead fall shield.