In BriefAccidental discharge of a fastener from a pneumatic nail gun can result in acute injury to construction workers or consumers. Such injuries most commonly impale the hands, arms and legs.
A smart trigger system can reduce the risk of acute injuries by detecting whether the surface is an intended substrate for fastening.
This article details the development of a smart trigger system, including testing methodology and results.
Pneumatic nail drivers, commonly called nail guns, are used in construction and manufacturing, especially with high-volume fabrication and production (Figure 1, p. 32). They are powered by compressed air, operated by a finger trigger and are particularly useful for repetitive, intensive operations, such as nailing wooden studs, floor joists and plywood sheathing, and fastening roofing materials such as shingles to sheathing. In the past 20 years, pneumatic nail drivers, some of which can insert up to eight fasteners per second, have effectively replaced the hammer for driving fasteners on construction sites.
Pneumatic tools have two main types of trigger modes. With a contact-actuated trigger (CAT) tool, a worker can repetitively discharge fasteners by continuously pressing the trigger and bumping the tool's nosepiece against the work surface. With a sequential-actuated trigger (SAT) tool, the worker presses the tool's nosepiece against the work surface and then presses the trigger to discharge a fastener. A SAT tool requires the worker to remove contact with the nosepiece and release the trigger before another fastener can be discharged. Wood frame building workers and residential roofers typically use CAT tools because they have higher production rates than SAT tools (i.e., more fasteners are installed per unit time).