BS EN 1804-1:2020 pdf download

BS EN 1804-1:2020 pdf download.Machines for underground mines-Safety requirements for hydraulic powered roof supports Part 1: Support units and general requirements.
3.2.3
goal shield
support component intended to absorb and transfer, fully or partially, the support bearing force and forces parallel to the seam between canopy and base
Note Ito entry: It Is connected to the canopy and base either directly or through a linkage. It generally shields the face area from the waste and is therefore subjected to a load from the caved material.
3.3
support accessories
all components which do not lie within the flow of the support bearing force but which are necessary for the functioning of the powered roof support
3.3.1
advancing mechanism
device attached to the support unit for moving the support forwards
3,3.2
sprag (flipper)
device attached to the support unit for supporting the working face
3.3.3
forepoling device
device used to protect the face area from caving materials
3.4
anchoring device
device for preventing uncontrolled movements of the conveying and extracting machines
3.5
forces
3.5.1
yield force
force produced by an actuator at the yield pressure of the pressure limitating valve, neglecting friction
3.5.2
rated Force
maximum force for which the support unit or support component is designed.
Note Ito entry: It Is a calculated value which is determined from the support geometry, neglecting friction,
3.5.3
support bearing force
force borne by a support unit normal to the strata, which is a function of the support height and which occurs at the yield force
3.5.4
test force
measured force required to be applied to the support unit or support component to ensure that it is subected to the rated force
3.5.5
additional force
force acting on the support unit, not produced by the strata or the support components
4.1.6 Lifting and pulling points
Support units shall have lifting and pulling points.
Lifting and pulling points shall be suitable for their intended purpose. They shall be designed to have a calculated minimum factor of safety of 4 on ultimate breaking load in relation to their intended load carrying capacity. They shall he clearly and permanently marked with their load carrying capacity. e.g. by welding.
4.1.7 Forepollng devices
Forepoling devices shall not lead to damage to other parts of the support unit when loaded with the rated force.
4.2 Stability and alignment requirements
4.2.1 Tilt-resistance
When handled in accordance with the manufacturer’s instructions support units in a freestanding state shall be stable over their whole adjustment range on all sides on a gradient of up to 15°.
In addition, they shall be stable in operation. e.g. with external stabilizing means.
4.2.2 Alignment
With support units for use in inclined seams with gradients of more than 30°, the alignment force (push or pull) of a support unit which is set shall be greater than the lateral weight component of three adjacent support units which are not set ii these support units are no longer stable In the free-standing state.
4.3 Design requirements
4.3.1 Yield capability
Support units shall be designed for yielding to absorb convergence between the roof and the floor. During convergence the rated force shall not be exceeded by more than 20 %.
Support units should be designed in such a way that their function is impaired as little as possible by caved waste when lowering.
4.3.2 Behaviour when overloaded
Support components including face sprags shall he designed so that no failure occurs by bending, tension and compression when they are loaded up to 1.2 tImes the yield force of their respective actuators.
4.3.3 Eccentric loading
Support units shall be designed in such a way that their ability to function is not impaired in the presence ct eccentric loading, e.g. if the canopy is in contact with the roof on one side only.
4.3.4 Loading resulting from caving or stowing
Support units shall be uapabic of withstanding the caving or stowing forces resulting from over tipping when operated on a gradient when working an over tipped face. The forces and the gradients to he expected are normally be provided by the user (see Introduction, last paragraph).