JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III MINE MECHANIZATION - II Previous Question Paper (March - 2021 - R16)

Safety features on a winding installation are critical to prevent accidents during the transport of men and materials. These features are categorized into those on the Headgear and those on the Winding Engine.

Safety Features on Winding Headgear:

• Detaching Hook: Installed between the rope capel and the cage chains. In the event of an overwind, it automatically detaches the cage from the rope and suspends it in the headgear frame.
• Catch Plates/Keps: Steel plates or beams located in the headgear to support the cage once it has been detached by the hook, preventing it from falling back down the shaft.
• Overwind Limit Switches: Electrical limit switches mounted in the headgear that trip the power to the winding engine if the cage travels beyond the normal tipping or landing level.
• Guide Ropes and Rubbing Ropes: Ensure the cage remains stable during travel and prevent collision with shaft sides or other conveyances.

Safety Features on Winding Engine:

• Automatic Contrivance (Slow Banker): A mechanical or electronic device that monitors the speed of the cage. It automatically applies the brakes if the speed exceeds the permitted limit at any point in the shaft or if the cage approaches the landing at an unsafe speed.
• Mechanical Brakes: Powerful brakes (usually disc or drum type) designed to hold the full suspended load. They are 'fail-safe', meaning they are applied by gravity or spring pressure and released by hydraulic or pneumatic pressure.
• Depth Indicator: A visual display showing the exact position of the cage in the shaft, allowing the driver to monitor travel.
• Emergency Stop Button: A manual override that allows the winder operator to cut power and apply full braking force instantly in an emergency.
• Interlocks: Systems that prevent the engine from starting if the brakes are applied or if the safety circuits are not closed.

Sketch Description: A simple vertical sketch would show the headgear structure at the top with the pulley wheels, the detaching hook located above the cage, and the limit switches mounted on the headgear frame. Below, the winding engine house would be depicted with the drum, the depth indicator, and the braking system connected to the drum shaft.