Electromechanical Switches in Work Vehicles are Here To Stay

Back in the 1990’s, there was talk among major manufacturers of construction equipment about completely eliminating switches with contacts by the year 2000.  Concerns about the durability of switches, environmental sealing against the elements, failures due to contact contamination or degradation over time due to arcing in high-endurance applications, and even cost, drove this school of thought.  
 

Innovations including wireless switches, RFID transponders, and reduced price points for inductive sensors were the big news in design publications of the day. Fast forward 20 years and while there has been a migration to proximity sensors and non-contacting devices for more consumer centric, or light duty applications, electromechanical limit switches continue to be an economical and robust design approach to control applications across a broad range of industries and an even wider range of applications.
 Sometimes, It is all about Quality

Unsealed, appliance grade limit switch

Customers expect equipment to work, everyday, in whatever conditions they can think of.  Nuisance field problems when switches fail due to harsh environmental factors are both costly to repair, and damaging to the brand. These quality expectations are thus passed to component manufactures via OEM requirements for long-term reliability, which continue to be more demanding year after year.  In the world of electromechanical limit switches, this has translated into new products designed to survive in much more challenging environments. In these applications, a durable, quality product though more expensive up front, has proved cheaper in the long run.
Electrical systems in mobile equipment have come a long way from the days of just accepting high failure rates of unsealed components.   Appliance-grade limit switches with screw terminals were a constant source of aggravation, topping the list for warranty claims on everything from commercial turf equipment to large wheel loaders.
As quality oriented manufacturers searched for better alternatives, they focused on replacing these nuisance components with more robust, sealed devices. They tried many solutions looking for the right cost and endurance tradeoffs from modified commercial components to high-end industrial controls and even mil-grade products.  Initially, there were only a few commercial options, and most of these were not truly sealed, waterproof solutions. 

Wire leads added to a standard microswitch helped robustness, but not by much, and definitely not truly waterproof. 

Wire leads plus enamel dip yet another early approach to improving environmental resistance to electromechanical switches.

While mil-grade switches meet the application demands, they are a very costly solution.

While all these switches represent valiant attempts to be good price/endurance/robustness tradeoffs, they all fail for different reasons ranging from sheer cost to lack of environmental immunity.
Arguably a switch family like our bracket mounted pendant switches, represent the ultimate evolution of the price performance curve in the world of electromechanical switches. Designed to withstand vibration and completely sealed in either Neoprene or Santoprene depending on your temperature requirements, these switches are actually submersible (really waterproof) and  fully IP68 rated for industrial applications where a military rated switch is really expensive overkill.

Truly waterproof, submersible (IP68) limit switch commonly specified to replace standard form-factor appliance grade switches.

Pictured on the left is one of our waterproof pendant switches enclosed in one of our many mounting brackets. This bracket is our “simulated roller” E1092 bracket commonly used in applications from door or hood closed detection, or end of travel sensing for mechanical systems involving arm or crane extension or outrigger deployment.  The bracket (and all our brackets) can be used with almost any of our B series pendant switches.
The flexibility of our system as well as the robustness of our solution makes it stand out in the world of electromechanical switch and sensor solutions. Designers can choose from hundreds of pendant switch variations with varying electrical parameters, current carrying capability, button heights, and custom lead lengths. In production quantities these switches are far more affordable than military versions, and even other IP68 rated switches that are not truly waterproof, only “water resistant.”
Getting High Endurance Switches To Work Isn't Easy

The J4 ball switch is one of the most environmentally immune switches in the world.

Over the past two decades, reliable, sealed component options have expanded every year.  Something as simple and common as a ball switch, for example, is now offered by CPI with a patented ball-carrier design, which prevents contaminates from jamming the ball.  
There are many more limit switch options for designers, both contacting and non-contacting. But electromechanical limit switches like those made by CPI are arguably the best price/performance tradeoff for commercial vehicles in the world. These switches do not require power to operate and have none of the finicky placement issues of cheaper magnetic or inductive sensors which can vibrate out of position and become unreliable.
Applications for electromechanical switches will never be completely displaced, given their simplicity of use and advantages in extreme duty application.
Call CPI today for more information on the right switch for your next application.

This blog was originally published at https://www.cpi-nj.com/electromechanical-switches-in-work-vehicles-are-here-to-stay/