Rocker Switch Alternative to Waterproof PVC Caps
April 2005
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Lamb Industries Inc. has introduced its WB2-Series of rocker switches as an alternative to traditionally used waterproof PVC caps. The supplier says the new line of switches utilize internal seals that separate electrical connections from the actuator, eliminating the need for a PVC cap.

Designed in four parts—an upper and lower body and two mounting ears—the body of the switch is said to successfully handle different application needs, such as electric housewares, commercial food equipment, and industrial tool and power equipment. “The body and the mounting ears are separate because they have conflicting requirements,” Carl Buchheit, design engineer, explains. “The body needs to be strong and dimensionally accurate at high temperatures, and the mounting ears need to be flexible without cracking.”

To meet the diverse requirements, the supplier says it designed the switch with different materials that are mechanically attached together. A rubber barrier is placed in between the upper and lower parts, sealing the actuator stem. According to Mr. Buchheit, the barrier also features an accordion shape that keeps a tight seal despite the motion of the actuator.

The rocker switches also feature a retaining piece that serves as one of the support surfaces for the rubber barrier and as a fixation device for the terminals. This, says Mr. Buchheit, eliminates a process called swedging. “Swedging usually creates a good seal around the terminal, but the occasional poor swedge may allow the terminal to push into the switch body when a connector is attached, and that is why we are not using it,” he explains. To prevent this, the supplier says it creates a water-resistant seal by using the retaining piece to apply pressure from the inside the switch, preventing the terminal from pushing into the switch body.

In addition, the size of the contact pads on the switch were increased to handle large electrical loads. Instead of using traditional 4-cu-mm silver-plated copper contact pads, the switches use 15-cu-mm size contacts. “This allows the contact pad to absorb more energy from the arc created during actuation, thus helping to prevent welding and increasing the electrical rating,” Mr. Buchheit says.

Because the switch eliminates the need to use a PVC cap, it is said to provide several advantages. “PVC caps are a good solution, but they are not ideal,” Mr. Buchheit tells APPLIANCE. “They interfere with the user’s interaction with the switch, dulling the tactile sensation and obscuring the view of the actuator position. Additionally, the cap may yellow, degrade, or crack with age.” The WB2-Series, however, provides a water-protected switch without a barrier to interface—all in a compact size.


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