If you’re a piece of switching electronics then the hot, dirty, oily, always moving environment of a military vehicle transmission is not a place you’d prefer to find yourself. After all some of these transmissions are in constant aggressive use and the crankcases get hot enough to fry eggs on. Add to that the constant exposure to hot transmission oil up to 150F, and if you’re most switches, you’re probably dreaming of a nice visit to Murmansk, on the Arctic Circle, doing some light duty as a dogsled horn.
In heavy duty transmission applications however, so called interlock switches are a critical part of safe operation. A typical such application is the detection of Neutral Safety in certain US Military Vehicles. This class of switch applications known as an interlock safety, is crucial to the safe operation of a 3 or 4 ton troop carriers or Humvee. The switch has to reliably detect when the truck is in neutral in order to enable other operations on or within the vehicle. No remote sensors will do for this application because to be really, really sure you are in neutral requires an actuator driven switch mounted in the transmission itself and thus exposed to the same punishing environment that any combat ready military vehicle is designed for.
CPI Switches Live in Hell, and Like it.
Specifically designed for punishing interlock applications in extremes of temperature and vibration are the CPI J4 Series Ball Switches below. Originally developed for military transports the switch has evolved and improved over decades of field use all over the world to become one of the most hardened solutions to interlock detection to be found anywhere on the planet.
The key to understanding the engineering beauty of the J4 can be summed up in two words: elegant simplicity.
As pictured the J4 boasts all stainless steel construction. While the switch can be procured in a ball or a plunger variation, the basic design is the same. At the heart of the J4 is a patented ball carrier design which prevents contaminates such as mud, dirt, ice, sand, dust, etc. from jamming the ball. The switch employ’s a patented double exclusion seal which actively removes contaminates from the housing during depression and release. This unique design effectively cleans itself and prevents early wear of contacts in a hostile environment. The switch is rated to perform from -50C to 185F and is one of the few switches in the world designed to operate while frozen in ice.
These switches are also ideal for heavy industrial equipment applications that are subject to the same conditions. The switches are completely submersible and are unaffected by water, salt spray, humidity, dirt, dust, sand, icing, oil, shock and vibration.
Just some of the applications for this switch have included:
- Back-up Alarm Switch
- Compartment Door Light Switch
- Dishwasher Door Closed
- Door Interlock
- Door Switch
- Hopper Down Detect
- Interlock Switches
- Nozzle Position Sensing
- Valve Position Sensing
- Neutral Safety Detection
Made in the USA too.
Our J4 Ball Switch and all our switches are painstakingly assembled right here in our factory in East Hanover New Jersey. As are all our products. It’s the only way to really have quality at this level and our competitors know it, having largely surrendered the field to us when it comes to these kinds of harsh duty applications.
Make the switch to CPI. Give us a call today to discuss your application.
Original content posted on https://www.cpi-nj.com/blog/NeutralSafetySwitches/
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When you take one of our Santoprene or Neoprene (extended temperature range) sealed momentary or maintained contact 
Perhaps the first thing to understand is that unlike virtually every other ball switch in existence, the J4 Series Ball switch is waterproof, period. Not splash-proof or “moisture resistant”. And not just water. The switch rejects oil, gas, dust, sand, mud, ice and all manner of airborne contaminants. Unlike the ball switches of some of our competitors it has no plastic parts. Variations of our switch can operate over a temperature range of -50°F to 185°F without locking up (cold side problem) or failing to make contact.
Most recently the J4 Ball received another design-in at a major manufacturer of armored vehicles. This time it will see use in a transmission sensing application where it provides feedback on gear range inside the transfer case (low, med, high).
One of the key features of Hagie sprayers is their long hydraulically controlled booms which can spread out on either side of the cab, yielding a wingspan of up to 132 feet! Critical to operation of these booms is that they travel to a locked position so that liquids are sprayed evenly and accurately. To provide closed loop feedback on the mechanical locking mechanism, a limit switch is typically used which is activated when the boom reaches its locked position. The problem however, is that these switches must be deployed in an area completely exposed to outdoor conditions on the boom including sprayed compounds like Urea Ammonium Nitrate (URN) which has excellent properties as a fertilizer when mixed with water. Unfortunately, it is also highly corrosive to steel over time and Hagie had difficulty finding a limit switch for this application that did not ultimately degrade, and require expensive field repairs.
Control Products, INC 