Appliance Design - August 2007 - (Page 19)

The two waveforms at left represent the normal resonance decay, or ringdown, without being touched. The two waveforms at right represent the accelerated decay when the resonator has been damped by a touch. SWITCHES & RELAYS ed to the surface. Illumination from the back of the touch surface can be provided by clear, epoxy-filled channels, or by bonding a graphic overlay with light guides on top of the surface. In addition, the active switch area that defines a touch can range from small to large, and can be curved or irregularly shaped. The technology can be employed as discrete, modular switch elements, or grouped together to form keypads and keyboards. Switch locations can be placed close together — up to six within a linear inch — making the technology feasible for even small control panels or portable devices. The combination of design flexibility, durability, and environmental sealing makes the new actuation technology suitable for a diverse range of applications, including outdoor power equipment, industrial equipment, commercial appliances, vending machines, ATMs, kiosks, security control panels, medical equipment, fitness equipment, and portable electronic devices subject to rough handling. < For more information, enter number . . . . . . . . . 305 Or email: info@itwactivetouch.com in. or less in order to produce the required deflection. Thicker materials require a larger force to actuate, making it more difficult for the user to operate. Limiting the top material thickness can be a drawback in applications where sharp impacts or potential vandalization are important issues. The required mechanical deflection also limits how closely the piezo elements can be spaced in a grouping, as on a keypad, for example. When placed too closely together, applying a force to one switch point might inadvertently activate an adjacent switch point due to the strain spreading across the surface material. And because piezo switches are actuated by strain in the material, they can be subject to false actuation when objects inadvertently come into contact with the switch or by pressure effects. Another disadvantage of piezo is that, unless advanced circuitry is employed, the output is typically only a brief, discrete pulse regardless how long the user presses the surface. By contrast, the ActiveSwitch can detect continuous touching by the user and utilize that awareness if desired in the application. be specified up to 1/2-in. thick to create an extremely durable device. The touch surface can be contoured for finger positioning or for other locating aids, and can incorporate Braille legends. Identifying legends can also be applied by engraving, etching, printing, or use of graphic overlays bond- TOWER– QUALITY TO PROTECT PEOPLE LCDIs • GFCIs • ALCIs LCDI GFCI ALCI • Customized to meet your specs • Priced from our own Asian plant to keep you competitive • Customer service from our USA headquarters for quick satisfaction Design freedom ActiveTouch switches also provide a product designer with a high degree of design flexibility. The surface material for an ActiveTouch switch can be virtually anything capable of exhibiting acoustic resonant properties, including glass, ceramic, hard plastics, metals, and even stone materials, such as granite. In some cases, the material can www.applianceDESIGN.com TOWERManufacturing Corporation 25 Reservoir Avenue, Providence, RI 02907 • Tel: 401-467-7550 • Fax: 401-461-2710 www.towermfg.com For more Information Enter 107 applianceDESIGN August 2007 19 http://www.towermfg.com http://www.towermfg.com http://www.appliancedesign.com

Table of Contents Feed for the Digital Edition of Appliance Design - August 2007

Contents Editorial Shipments/Forecasts News Watch A Reed Switch is Simople, yet Versatile, and Designers are Finding New Uses for this Time-Tested Technology A Novel Actuation and Sensing Technology can Register a Light Touch, but Resist Blows from a Hammer Tracing the Source of Noise is Made Easier with Noise Source Identification Methods Appliance Noise can be Annoying, but Designers have Many Material Choices to Help Rein in the Racket Nanocomposites are No Longer a Technology for the Future. These Plastic Materials are Already on the Job A New High-Strength, Low-Density Glass-Microsphere Additive can Improve Plastic Part and Molding Performance A New Electromagnetic Weld/Bonding Process Helps Ensure Long-Term Integrity of Joints in Plastic Parts Snap-Based Technology Eases Installation and Makes Products More Serviceable Two-Part Silicone Adhesives Provide a Rapid-Cure Alternative to Traditional One-Part Silicones Classified DesignMart Advertiser’s Index Association Report: GAMA

Appliance Design - August 2007

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