Reed switches in Safety Vane applications
The automation industry depends on feeding systems which feed parts of different shapes into the assembly machine. The most cost effective feeding systems are vibratory which start in bowls and end in linear feeders prior to the actual pick and place to the machine. For the pick up arm to be accurate, the vibration on the linear feeder needs to be turned off and this is done when the linear feed has been fed with parts and is fully loaded. Usually, optic sensors are used but for this, the lenses need to be exceptionally clean and this is not usually the case for industrial automation. Reed Switch based Vane Sensors are the answer to this. A reed switch and a magnet are combined into a single package with which maintains a fixed distance between them to form a Normally Closed vane sensor. When ever a ferrous part, which is the “vane”, comes between them, the magnetic field is shunted and the reed switch opens. Normally Open vane sensors can be designed by using a Normally Closed reed switch on one side and a magnet on the other side which is strong enough to keep the NC reed switch open. Reed switch based vane sensors can work in very dirty industrial environments and grease and dust do not affect its working. Common applications are conveyor belt part sensing, industrial mixer speed sensing, etc.