Pull Cord Switch Working Principle

Pull Cord Switch is an emergency switch to stop the belt conveyor instantly when an accident happens. Since the Pull Cord Switch is so designed that it should be installed at the side of belt conveyor and the pull cord should be mounted along conveyor, the switch can be actuated at any position.

Pull Cord Switch is a switch that is mounted along a conveyor stringer and is manually actuated by a cord that runs the full length of the conveyor. The cord can then be pulled at any point on the conveyor as an emergency stop.

Pull Cord Switch Principle

The Pull Cord Switch is installed at the side of belt conveyor and the pull cord is mounted along the conveyor. When an accident occurs in the belt conveyor, the worker can stop the belt conveyor at any position with pulling the cord in order to drive the actuating arm rotating.

Pull Cord Switch Conveyor Belt

Image Credits : phisher-ct

The rotation may put the torsion spring in motion through the transmission shaft to drive the cam into the displacement. Then it may drive microswitches to cut down the control wiring. Thus the belt conveyor can stop operation

Construction

As these Switches are used as safety or emergency switch , it is not operated very frequently therefore construction of these switch is such that it should be operated immediately though it kept idle for long time.

Pull cord switch is housed in dust and weatherproof enclosure with IP65 grade of protection. Sturdy and heavy-duty cam-switch with robust contacts is used to give longer service life.

Pull Cord Switch Working Principle

Image Credits : phisher-ct

Operating handle fitted with spring steel rings at both ends for fixing the rope. The design of the rings gives maximum flexibility in operating condition. Enclosure is epoxy painted to give high corrosion resistance. The switch is designed with manual reset type of mechanism.

Operation

Pull cord switch is mounted on the walkway side of the conveyor belt, preferably at about every 20-25 meters. When the rope is pulled from any side. The switch get operated . Unless and until the handle is reset to normal position manually, the switch remains in operated condition.

All the pull cord switches installed along an individual belt are electrically wired in series and connected to the control station by a two core cable. Therefore actuation of any one of these pull cord switches will stop the concerned conveyor until the particular switch is manually reset.

Application

Pull cord switch also known as Rope Operated Emergency switch is used as a safety switch to stop the conveyor belt in case of an emergency. It is also known as pull switch cord.

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Pull Cord Switch Working Principle

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