Hampstead, MD--To communicate confidence in its products, the DEWALT Industrial Tool Co. promotes its tools as "Guaranteed Tough(TM)." It backs them with a one-year warranty and a one-year free service contract, including parts and labor. But DEWALT doesn't stop there. As part of its product development, the company designs tools to exceed end-user expectations and to take advantage of emerging technologies.
With this objective in mind, and as a result of significant end-user research, DEWALT recently launched redesigned versions of its leading drywall screwdrivers introduced some 14 years ago. They include: the DW251, a 4,000-rpm general-duty model; the 274/DW274W, a slightly more powerful model for installing screws in steel stud framing or hanging sheet rock; and the DW276 and DW257-2,500 rpm models with higher torque for heavy-gauge steel framing and for driving longer fasteners in wooden decks.
"In this upgrade, we improved the ergonomic features and added more power to the products," explains Rick Brannaman, senior project manager for DEWALT. "Drywallers hold the screwdriver by its handle with their arms and hands in a straight line. This position can make the operator's arm weary during the work session. Thus, a comfortable, non-slip grip and overall light weight were keys to making the tools more comfortable," Brannaman says.
For the ergonomic upgrades, the drywall screwdrivers now have an enhanced comfort handle designed to accommodate a variety of hand sizes. The handle helps the operator hold the screwdriver in a straight-line position to more accurately perform the work, while avoiding hand strain and off-target fastener placement. The handle's "soft touch" provides a more comfortable grip and helps prevent slips.
To give the added toughness, the screwdriver's handle, motor housing, and trigger consist of Capron(reg) 8333GHI nylon 6 resin supplied by AlliedSignal Plastics (Morristown, NJ). The material combines the strength and stiffness of a glass-reinforced compound with a high level of impact strength.
DEWALT and AlliedSignal began the R&D phase of the housing redesign about two years before the launch. For the redesigned handle and motor housing, the design team settled on AlliedSignal's heat-stabilized, 33% glass-reinforced nylon 6 Capron because of its balance of strength, stiffness, and moldability/surface aesthetics.
For the soft-touch trigger design, the Capron resin is bonded to Santoprene(reg) thermoplastic vulcanizate (TPV) supplied by Advanced Elastomer Systems (AES, Akron, OH). The resin duo resulted from AlliedSignal's joint marketing alliance with AES. Under the agreement, the two companies develop applications and markets for new grades of Santoprene specifically developed to chemically bond to AlliedSignal's Capron and Nypel(reg) resins. The colorable, patented TPV joins with the plastic resins without the use of primers or adhesives. This strong bond offers design freedom and significant cost savings in challenging rubber/metal part designs, as well as advantages in heat aging, oil resistance, and colorability, according to Scott Conway, AlliedSignal's market development manager.
In developing the design and specifications for the screwdrivers, AlliedSignal and AES performed a stereolithography of the products as they evolved. This step permitted a prototype mold design to be created, greatly reducing the time needed to design prototypes in CAD form and prepare them for mass production.