The invention discloses a protective device for the occurrence of a mine roof fall, which includes a machine body. A load-bearing cavity 72 is provided in the machine body 10, a load-bearing platform 11 is fixedly arranged on the lower side of the machine body 10, and four circumferences of the machine body 10 are evenly distributed on the outside. The cavity 69 and the load-bearing cavity 72 are provided with a weight-bearing device 75 for lifting a weight. The weight-bearing device can withstand the falling top plate, and the hydraulic cylinder therein can make the device bear the pressure of the top plate on the device and fix the device at the same time. The stabilizing device can keep the device in a stable state under the action of pressure, will not fall, and share part of the pressure. The load-bearing device can support the device to support the pressure on the roof of the mine and drill into the ground. The fixing device can effectively Reduce the harm caused by the mine roof accident, reduce the accident casualties and various losses, and increase the safety rate in the mine production.

The invention discloses a protective device for the occurrence of a mine roof fall, which includes a machine body. A load-bearing cavity 72 is provided in the machine body 10, a load-bearing platform 11 is fixedly arranged on the lower side of the machine body 10, and four circumferences of the machine body 10 are evenly distributed on the outside. The cavity 69 and the load-bearing cavity 72 are provided with a weight-bearing device 75 for lifting a weight. The weight-bearing device can withstand the falling top plate, and the hydraulic cylinder therein can make the device bear the pressure of the top plate on the device and fix the device at the same time. The stabilizing device can keep the device in a stable state under the action of pressure, will not fall, and share part of the pressure. The load-bearing device can support the device to support the pressure on the roof of the mine and drill into the ground. The fixing device can effectively Reduce the harm caused by the mine roof accident, reduce the accident casualties and various losses, and increase the safety rate in the mine production.

A hydraulic cylinder is disclosed. The hydraulic cylinder may have an outer cylindrical tube including an open end, a first female threaded portion, and a second female threaded portion. The hydraulic cylinder may also have a movable element received in the outer cylindrical tube through the open end. Further, the hydraulic cylinder may have a sleeve holder engaged with the first female threaded portion to seal an annular space between the outer cylindrical tube and the movable element. The sleeve holder may have a first male threaded portion mating with the first female threaded portion. In addition, the hydraulic cylinder may have a locking ring engaged with the second female threaded portion to secure the sleeve holder to the outer cylindrical tube. The locking ring may have a second male threaded portion mating with the second female threaded portion.

The support 10 of the present invention resembles a conventional Acrow prop which may be used for temporarily supporting a load. In particular, the present invention is arranged to support a surface at a static position. For example, the surface may comprise a ceiling/beam/lintel within a structure wherein the usual permanent supports for the ceiling/beam/lintel are being replaced or deemed temporarily insufficient. However, the present invention can be used in numerous situations where a support 10 is required and for which the support 10 can be quickly and easily installed. The present invention provides (hydraulic) movement means to move the upper end relative to the lower end. In addition, the present invention provides retraction prevention means to prevent the upper end moving towards the lower end while supporting the load and prevents the inner core member 14 being forcibly retracted back into the outer sleeve member 12 due to the compressive force of the load. A hydraulic ram 22 has a maximum extension limit and the present invention uses an adjustable mounting/abutment mechanism which means that a relatively small hydraulic ram 22 can be installed in the outer sleeve member 12. This size of hydraulic ram 22 will then be suitable for all heights and the support is not limited to simply being moveable within a restricted range.

The support 10 of the present invention resembles a conventional Acrow prop which may be used for temporarily supporting a load. In particular, the present invention is arranged to support a surface at a static position. For example, the surface may comprise a ceiling/beam/lintel within a structure wherein the usual permanent supports for the ceiling/beam/lintel are being replaced or deemed temporarily insufficient. However, the present invention can be used in numerous situations where a support 10 is required and for which the support 10 can be quickly and easily installed. The present invention provides (hydraulic) movement means to move the upper end relative to the lower end. In addition, the present invention provides retraction prevention means to prevent the upper end moving towards the lower end while supporting the load and prevents the inner core member 14 being forcibly retracted back into the outer sleeve member 12 due to the compressive force of the load. A hydraulic ram 22 has a maximum extension limit and the present invention uses an adjustable mounting/abutment mechanism which means that a relatively small hydraulic ram 22 can be installed in the outer sleeve member 12. This size of hydraulic ram 22 will then be suitable for all heights and the support is not limited to simply being moveable within a restricted range.

An automatic support device for resisting rock burst in mines is provided, which includes bases symmetrically distributed, sliding frames are slidably connected to the bases, hydraulic rods are fixedly connected to the bases, and telescopic ends of the hydraulic rods are fixedly connected to the adjacent sliding frames. The sliding frames are fixedly connected to brackets, and the brackets symmetrically distributed are provided with a main support plate, on which pushing rods are provided. The device can slow down the impact force of the device when rock burst occurs in the mine, at the same time, it plays a supporting role in the mine, ensuring the stability of the roof of the mine.

An automatic support device for resisting rock burst in mines is provided, which includes bases symmetrically distributed, sliding frames are slidably connected to the bases, hydraulic rods are fixedly connected to the bases, and telescopic ends of the hydraulic rods are fixedly connected to the adjacent sliding frames. The sliding frames are fixedly connected to brackets, and the brackets symmetrically distributed are provided with a main support plate, on which pushing rods are provided. The device can slow down the impact force of the device when rock burst occurs in the mine, at the same time, it plays a supporting role in the mine, ensuring the stability of the roof of the mine.

A support comprising an outer casing having a main axis, the outer casing comprising a first casing part and a second casing part, the first casing part being at least partially receivable within the second casing part to enable relative movement therebetween in the axial direction, the casing parts having a cavity therein at least one of which has a core that includes a compressible medium, the support further including a pressure responsive system configured so that under the influence of pressure it can cause the relative displacement or movement between the first and second casing parts.

A support comprising an outer casing having a main axis, the outer casing comprising a first casing part and a second casing part, the first casing part being at least partially receivable within the second casing part to enable relative movement therebetween in the axial direction, the casing parts having a cavity therein at least one of which has a core that includes a compressible medium, the support further including a pressure responsive system configured so that under the influence of pressure it can cause the relative displacement or movement between the first and second casing parts.

The present disclosure provides an apparatus for forming an underground tunnel. The apparatus comprises a cutting head for removing material from a wall portion of the tunnel and thereby forming a portion of the tunnel. Further, the apparatus comprises a support structure for supporting a previously formed portion of the tunnel. The support structure is arranged to provide a supporting force against a surface of the tunnel when stationary and when being moved along the tunnel. Further, the apparatus comprises a conveyor for conveying removed material from the cutting head to a location remote from the cutting head during formation of the portion of the tunnel.