Our contemporary floor machines were ready for the resurgence of demand that has followed the pandemic. These new models had many fascinating features, accumulated from the multiple iterations before them. They were more durable, they lessened labor, and they built a quality truss, embedding all of the plates properly. Even so, these advancements hadn’t come quickly. It took 30 years of trial and error and millions of miles of floor trusses, but they made the floor truss machine robotic-ready.
The forerunner of the modern machine, Ronnie Wright’s 1979 Fatman, established a corollary to the theory that truss plates must be double rolled for proper embedment. Although he initially believed otherwise, Wright found from later experience that a single roll can fully embed the top plate only if there is precise control of the gap between the roller and the table. And machines that allowed any variance in that gap would not be around long.
The Fatman picked up another capability in 1984 that was intended to maintain high quality joints without gaps. Wright’s partner, Mike Rosser, repurposed a fire hose, inflating it with air rather than water, and used it to continuously clamp trusses tightly into their jig. This greatly simplified the machine, ridding it of air leaks and damage to cylinders. While this use of fire hoses was an effective method of clamping, depth adjustments became more difficult, so later machines retained air cylinders for their dual capabilities. However, Rosser’s invention highlighted the advantage of removing or relocating the air system from on top of the table, which protected its vulnerable components while trusses were being flipped. This also created additional room on the table top for labor-saving mechanisms such as are shown here schematically in the area between the air hose assemblies. And this became a compelling benefit going forward. [For all images, See PDF or View in Full Issue.]
One of the first machines to leverage this advantage was MiTek’s roller floor machine, which was a scaled-down version of the roof gantry system that they had acquired from Bob LePoire’s Diamond Machinery. This table used a series of devices, later called trucks, that were connected every few feet to the side of the steel clamping angle. The bottoms of these trucks were attached to air cylinders operating beneath the table. This arrangement not only protected the air system but cleaned up the table top.
Despite these advantages, this machine design ran contrary to Wright’s corollary, because the gantry ran on a track attached to a floor that might not be level, resulting in unseated plates. Likewise, TeeLok’s and Klaisler’s early floor gantries were driven on a railroad track on the floor.
In 1997, MiTek introduced their RailRider, adhering to Wright’s corollary. The third and fourth iterations of this machine went to Builders FirstSource’s first plant and are still running daily. Note the redesign of the trucks that now ride on four small solid wheels to improve their movement across the table’s surface.
Klaisler and Pacific Automation also recognized the need to support their floor gantry on the structure of the table, however, they simply raised the railroad track from the floor and attached it to the legs of the machine.
By the late 1990s, as the industry had reached a consensus on floor table design, manufacturers began the quest to add labor-saving features to their machines. Most had already offered pop-up air cylinders that raised the truss from the table so that it could be more easily grasped to be flipped or ejected, like Ronnie Wright had done much earlier. Now that the table top was clear of vulnerable air system components, it became possible to add a mechanism to flip trusses to the other side of the table. The first such design by MiTek included one arm to raise the truss to a near-vertical orientation and another to receive it and lay it down. The rationale for this design was to ease the truss downward to avoid injury to a crew member, however, the descent of the flipper created a pinch point that presented the same risk.
At the same time, Dave McAdoo, along with Mike Rosser, was perfecting a groundbreaking full-featured machine (including sloped top chords) that protected the back-end operator. Alpine’s Speed Roller came to the market in 2002 using what Dave termed “Flip-Overs” and “Lift-Outs” that worked in the proper sequence and were synchronized with the clamping rails. That way, the flipping truss always landed inside those rails, ready to be clamped and back-plated. And, for Dave, this was just the beginning of a phenomenal machinery tour de force (see Dave’s article, “One Hundred Five Days in 2002,” for more on that story). Ten years later, Alpine capped off this era of conventional technology with their Floor Master, as MiTek did with their RailRider Pro, having just shipped their 600th machine in this series.
Just as a record number of the latest floor machines are being installed, the next level of technology is being exploited on the House of Design’s robotics line at BFS in Villa Rica, Georgia (see my column from August 2022, “The Last Word on the Promise of Robotics,” for details). Ironically, the floor truss table and gantry used there are largely the same as the conventional machines being installed, minus some of the options. Like those legacy machines, there is no automated jigging for the increasingly common, multi-piece floor details. And those special details are what make floor trusses preferable to I-joists.
Next Month:
The Devil in Those Details
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