Provided is a base mechanism of a single prop capable of being unloaded at reduced pressure, including a base bottom plate and two wedge-shaped support blocks, where one of the wedge-shaped support blocks serves as a fixed wedge-shaped support block and is welded onto the base bottom plate, and the other of the wedge-shaped support blocks serves as a movable wedge-shaped support block and is connected to the fixed wedge-shaped support block by using a screw rod and a nut. The present invention can effectively unload the single prop at reduced pressure or remove the single prop in a contracted manner, is of a simple structure, is convenient to operate, has a good use effect, overcomes the technical problem that it is difficult to unload a single prop at reduced pressure in this technical feature, and is widely applicable in this technical field.

Provided is a base mechanism of a single prop capable of being unloaded at reduced pressure, including a base bottom plate and two wedge-shaped support blocks, where one of the wedge-shaped support blocks serves as a fixed wedge-shaped support block and is welded onto the base bottom plate, and the other of the wedge-shaped support blocks serves as a movable wedge-shaped support block and is connected to the fixed wedge-shaped support block by using a screw rod and a nut. The present invention can effectively unload the single prop at reduced pressure or remove the single prop in a contracted manner, is of a simple structure, is convenient to operate, has a good use effect, overcomes the technical problem that it is difficult to unload a single prop at reduced pressure in this technical feature, and is widely applicable in this technical field.

An apparatus for protecting a roof tray when a gob-side entry retaining end support migrates is provided. The apparatus is mounted at a top end position of a hydraulic support, and includes a movable bearing mechanism, an automatic expansion/contraction connecting groove mechanism, and an active reset mechanism. The movable bearing mechanism includes two parallel belts and a plurality of rollers supporting the belts, and the rollers are mounted on and supported by a bearing mechanism. The automatic expansion/contraction connecting groove mechanism is two concave base plates fixed between the two belts, and the two concave base plates are spaced by a distance. The active reset mechanism includes two telescopic rods and reset springs sleeved on the telescopic rods, and the telescopic rod is connected to an end portion of the reset spring to form a synchronous mechanism.

Provided is a base mechanism of a single prop capable of being unloaded at reduced pressure, including a base bottom plate and two wedge-shaped support blocks, where one of the wedge-shaped support blocks serves as a fixed wedge-shaped support block and is welded onto the base bottom plate, and the other of the wedge-shaped support blocks serves as a movable wedge-shaped support block and is connected to the fixed wedge-shaped support block by using a screw rod and a nut. The present invention can effectively unload the single prop at reduced pressure or remove the single prop in a contracted manner, is of a simple structure, is convenient to operate, has a good use effect, overcomes the technical problem that it is difficult to unload a single prop at reduced pressure in this technical feature, and is widely applicable in this technical field.

Provided is a base mechanism of a single prop capable of being unloaded at reduced pressure, including a base bottom plate and two wedge-shaped support blocks, where one of the wedge-shaped support blocks serves as a fixed wedge-shaped support block and is welded onto the base bottom plate, and the other of the wedge-shaped support blocks serves as a movable wedge-shaped support block and is connected to the fixed wedge-shaped support block by using a screw rod and a nut. The present invention can effectively unload the single prop at reduced pressure or remove the single prop in a contracted manner, is of a simple structure, is convenient to operate, has a good use effect, overcomes the technical problem that it is difficult to unload a single prop at reduced pressure in this technical feature, and is widely applicable in this technical field.

A grout tillable prop assembly for supporting a ceiling such as the ceiling of an underground mine. The prop assembly comprising an inner member and an outer member adapted for movement between an extended use configuration and a retracted configuration, a unidirectional grout inlet in an upper part of a sidewall of the outer member to allow grout to pass into the prop, the inner member and the outer member having wall portions and being self-supporting, an air conduit through the prop having an opening adjacent an upper limit of the prop, a pressure relief valve coupled to the air conduit whereby the prop is be brought from the retracted configuration to the extended configuration by application of pressurized air through the air conduit and whereby the extended prop is filled with grout via the unidirectional grout inlet.

New prop assemblies, suitable for a range of uses, including in mines and construction, have a pole subassembly. The pole subassembly includes: a first prop part and a second prop part, the first prop part being axially movable with respect to the second prop part; a first extending means adapted to enable the first prop part to be moved in a first adjustment with respect to the second prop part; and either or both: a second extending means adapted to enable the first prop part to be moved in a second adjustment with respect to the second prop part; or a third extending means, adapted to adjust a length of the prop assembly.

New prop assemblies, suitable for a range of uses, including in mines and construction, have a pole subassembly. The pole subassembly includes: a first prop part and a second prop part, the first prop part being axially movable with respect to the second prop part; a first extending means adapted to enable the first prop part to be moved in a first adjustment with respect to the second prop part; and either or both: a second extending means adapted to enable the first prop part to be moved in a second adjustment with respect to the second prop part; or a third extending means, adapted to adjust a length of the prop assembly.

The present invention relates to an adapter for a formwork support structure comprising a formwork support of a first type, the adapter comprising a mount for positioning the adapter with respect to said formwork support of a first type, said mount supporting a formwork support of a second type. In one form, the mount positions the adapter with respect to a crown type formwork support, and the mount supports a bearer support portion.

A mine prop includes a first pipe having a first end and a second end, a second pipe having a first end and a second end, and a yield member secured to the second pipe. The second pipe is slidably received in the first pipe. The yield member is configured to yield before the first and second pipes when the mine prop is placed under a predetermined load.