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HAYDON SEALED SWITCHES

Haydon's sealed switches are used in commercial jets, military aircraft, military ground equipment, space applications and industrial applications with harsh enironmental conditions, such as gas turbines and high temperature research instrumentation. Haydon switches are built to meet stringent military specifications and are requalified through extenvive retesting every three years. To achieve and sustain such high levels of quality requires a combination of skilled engineering and production teams, special support facilities and coordinated quality control from design through production. Haydon has all of these factors in place and, because of this, our switches are recognized for their quality and robustness by engineers and users throughout the world. The unique manufacturing methods, process controls and quality systems utilized in the production of our advanced aerospace switches are also integral parts of our motor operations. See switch comparisons >>

Custom Designs
Haydon Kerk Motion Solutions' qualified application engineers will work with you in developing cost effective solutions to meet your requirements. We also offer complete in-plant, tool-and-die making capabilities for the fabrication of prototypes, and we can provide in-depth testing to insure that your switch offers reliable performance.

See also this page: Technical Overview | Switch Features

 
ENVIRONMENTALLY SEALED SWITCHES
Designed for applications where high reliability is required in a high or low temperature environment. Also available as non-sealed, Ultra High Temperature. Assemblies: pushbutton, toggle leaf actuators & roller leaf assemblies
Designed for high cycle harsh environment applications, this switch is rated for one million cycles Assemblies: pushbutton, toggle leaf actuators & roller leaf assemblies
 
HERMETICALLY SEALED SWITCHES
Ideal for high temperature applications or anywhere extremely severe environmental conditions are encountered. Also available in low-current version. Assemblies: standard assemblies rated up to +660°F continuous operation and up to +800°F intermittent operation
Designed for high reliability in extreme environments, including valve limit switches, engine starters, overspeed switches, pressure switch and thrust reverser limit switches Assemblies: pushbutton, leaf, roller leaf and toggle assemblies
Designed for harsh environments where long life hermetic seal integrity of the switch is critical. Assemblies: leaf actuators, roller leaf assemblies and plunger actuators
Designed to provide reliable operation in extreme environments in various applications on commercial jetliners Assemblies: leaf and roller leaf configurations
 
HIGH ELECTRICAL LOAD SWITCHES
This switch incorporates high electrical load capacity, extreme ruggedness, accurate repeatability, and sensitive operating characteristics.
This switch incorporates high electrical load capacity, extreme ruggedness, accurate repeatability, and sensitive operating characteristics.
 
CUSTOM ASSEMBLIES
A single pole single throw push-button switch available in normally closed or normally open versions
A rotary style switch designed to operate at specific angles.
A rugged pushbutton type switch used in heavy-duty applications available with various mounting configurations and a variety of contact ratings
Available in single and multi-switch configurations with either Environmentally or Hermetically Sealed switches for a wide range of applications
Available in single and multi-switch configurations with either Environmentally or Hermetically Sealed switches for a wide range of applications
 
Technical Overview: Precision Snap Action Switches

Haydon’s snap action switches are designed to deliver reliable performance and long life under extremely harsh environmental conditions. Switches are designed and tested under specific conditions to insure their reliability and stability. To obtain the best performance it is important to operate a switch in a manner consistent with its design. A basic understanding of switch characteristics and terminology will enable the user to optimize switch performance for their application.

Basic switch components include an external actuation mechanism, a transfer blade, contacts, terminal posts, and an internal actuator, figure S1. In addition to these components, Haydon’s sealed switches incorporate a glass-to-metal sealed header. A resilient seal around the actuating pin, a wobble diaphragm or a bellows is used as a means of actuating the switch through the sealed housing.

 

 
Switch Features


One Piece Blade
Haydon’s snap action switches utilize a patented one-piece moveable blade. This design has the advantage of maximum cross sectional area for highest load carrying capacity. The one-piece blade also provides high contact pressure, even near the trip point, thereby enhancing vibration resistance and decreasing contact resistance. Blades are constructed of beryllium copper or Elgiloy. The specific blade configuration, material and thickness used depends on application parameters such as temperature, life requirements and vibration.

Switch Mechanism
The internal switch mechanism consists of the one-piece blade, internal actuator and contacts mounted directly on the terminal posts (figure S1). This construction assures a reliable and rugged mechanism for long operating life.

Seal
Haydon produces switches which meet resilent sealed and hermetically sealed classifications per MIL-PRF-8805 enclosure types 4 and 5. Resilent sealed switches have a leak rate not exceeding 1x10-6 atm cc/sec. Hermetically sealed switches have a leak rate not exceeding 1x10-8 atm cc/sec.
Terminal poles are part of the glass-to-metal header assembly which is welded or soldered directly to the switch housing. The terminal seal does not depend on potting compound, plastics or organic material. This construction assures a reliable and rugged sealed assembly for long operating life.
Actuation of the internal switch mechanism must be accomplished through some type of seal. Haydon’s hermetically sealed switches are actuated through a wobble diaphragm or metal bellows which insure seal integrity. Haydon’s resilent sealed switches incorporate a resilient elastomeric seal bonded to the housing and actuating pin. During construction Haydon’s sealed switches are evacuated, filled with dry nitrogen, sealed and subjected to an altitude immersion leak test.

Contacts
Fine silver, gold alloy, platinum, or silver cadmium oxide contacts are available. Selection will depend on the current and temperature requirements of each application. Fine silver is typically used for applications requiring 1 amp to 5 amp ratings. For low level applications (<1 amp) gold alloy contacts are used. Platinum contacts are typically used for high temperature. Silver cadmium oxide contacts are used for applications up to 10 amperes, but life rating is reduced at high amperage.