Design News, February 2013

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Materials & Assembly • Challenge: How to avoid off-angle thread engagement and potential thread damage during assembly. Self-clinching, flare-mounted, and floating captive panel screws can be engineered with patented anti-cross threading technology, which easily corrects off-angle installations, aligns components, and slides through clogged internal threads. During initial engagement when threads come into contact, the anti-cross threading feature begins to cam over the female thread. The two thread helixes then align perfectly and fasteners drive normally and quickly with reduced effort. Specifying this feature can save time and money by eliminating failures, repairs, scrap, and downtime associated with thread damage. Source: PennEngineering Self-clinching spring-loaded plunger assemblies enable repositioning of racks, drawer slides, access panels, and equipment consoles without requiring tools. After a mounting style of the captive panel screw has been selected, a fastener's features and functions can help guide design engineers to the best picks. Particular capabilities — engineered or otherwise — can resolve many of the typical challenges that can be anticipated in an application. Following are some of these challenges and how they can be readily dispatched. There Is an Alternative... • Challenge: How to enable tool-only access. Several types of captive panel screw products have been UL-approved for tool-only operation and benefit from fully recessed heads and Phillips drives. These types are especially well-suited to applications where security or safety issues can be expected to arise. Tool-only access also has become a top-of-mind issue due to a recent European Commission machinery directive that imposes strict safety requirements for machine guarding and the ergonomics of operator equipment. For example, PEM captive panel screws for tool-only access specifically conform with Machinery Directive 200642/EC, which requires such fasteners to remain attached to fixed guards or to machinery when guards are removed, which means that loose screws are no longer acceptable. • Challenge: Prevent "over installation" of the fastener. A shoulder on the retainer of a captive panel screw provides a unique positive stop during installation and prevents over installation. The shoulder can help to square up the fastener during off-angle installations. • Challenge: How to satisfy an in-service need to reposition equipment. Self-clinching spring-loaded plunger assemblies often serve as positioning pins. These can let users quickly move racks, drawer slides, access panels, and equipment consoles, among other objects, to new positions without requiring tools. Standard versions incorporate a unique lockout feature to keep the fastener's spring-loaded plunger retracted until the plunger pin drops into its final position. A simple quarter-turn of the fastener enables the retracted locking and unlocking actions. These types of captive panel screws promote fast installation and removal of components. Fasteners also can be supplied without the lockout feature. Tired of wrestling with heavy, cumbersome loads? Airfoat technology provides a safer, less costly & more ergonomic alternative to traditional material handling equipment. 800-888-0018 Air Bearing Equipment • Lift & Tilt Tables • Turntables • Assembly Lines Ergonomic Equipment • Transporters • Rigging Equipment Design News | february 2013 | www.d esign n –48–

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