Appliance Design - August 2007 - (Page 40)

JOINING Wing Spring Channel Fig. 2. Internal view of a D-SNAP element. for other methods. The technology, therefore, has the potential to shorten the duration of general service calls. Currently used in the assembly process of industrial enclosures, this technology is also well-suited for residential and commercial appliances, heating and air conditioning equipment, vending machines and kiosks, medical equipment, and electronic cabinets. The technology has been integrated into a wide assortment of fastening products including panel fasteners, hinges, handles, locks, and latches. Advantages of this technology include: 4Quicker and easier installation. 4Tool-free assembly. 4Blind assembly from one side. 4Quick disassembly and reinstallation. 4Suited for automated assembly. Fig. 3. D-SNAP element can be easily disengaged for removal. Fig. 4. The D-SNAP fastener adapts to different panel thicknesses by varying the distance between the head and clamping pitch. 40 applianceDESIGN August 2007 4Reduced downtime for service. 4Reduced inventory requirements. 4Vibration resistance. 4More secure installation. The technology hastens the servicing of an appliance by making it easier to remove access panels. The lack of threaded fasteners also eliminates the possibility of small parts falling into sensitive equipment during servicing. Once service is completed, the panels can be securely reinstalled just as quickly with the same clamping force that was achieved in the factory. The basis for the technology is like the spring lock commonly used for doors in homes. In closing a door with a spring lock, the beveled spring bolt is pushed against the pressure of the spring, past the edge of the striking plate in the door frame, and into a guide channel. As soon as the spring bolt passes the edge of the striking plate, it springs out of the guide channel. The force of the tensioned spring inserts it into the striking plate, which securely locks the door. Not until activation of the latch is the spring bolt pulled out from the striking plate and back into the guide channel so that the door can be opened. In similar fashion, a D-SNAP element consists of only two parts — the guide and the spring which seats in a cutout within the guide. (See Fig. 2.) The guide includes single or multiple triangular wings at the ends that are defined by the wing pitch and clamping pitch. For installation, the D-SNAP fastener is simply pushed through the rectangular cutout. Once the wing pitches have cleared the cutout, the D-SNAP elements snap automatically into position due to the pressure force from the compressed spring. (See Fig. 1.) Installation is complete once the “click” sound is heard. This tool-free assembly method is quick and secure. Removing the fastener is trouble-free and can be achieved by using a socket, screwdriver or key. (See Fig. 3.) The D-SNAP elements are pulled back into the channel against the spring force, and the D-SNAP fastener can be easily pulled out. The only part design change required to employ the new technology is to use a rectangular cutout instead of a round hole. Since most cutouts are punched by a turret press or cut by lasers, changing the cutout shape simply involves reprogram15 degree ming the equipment. Even angle though punched-hole sizes vary by application, commonly used standards have evolved over time. The same applies to the rectangular cutouts. D-SNAP fasteners are made in the length and width dimensions most frequently used. Given that space is often tight in most applications, the fasteners need to have as little www.applianceDESIGN.com C p 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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