Sixty Years of Machines, Part VI

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Issue #12250 - May 2020 | Page #10
By Joe Kannapell, P.E.

Part VI: Roller Gantries Enhanced

As housing boomed in the mid-1980s, truss plants needed better equipment. Among those was Heart Truss and Engineering in Michigan. Heart was also benefitting from booming auto plants nearby. Their production head, Bob LePoire, pondered how to keep up. Bob’s boss and Heart’s co-founder, Don Butcher (father of current owner Joe Butcher), had assembled an array of single-purpose roof truss equipment in his plant, “specifically suited to the task at hand,” as Don had explained to me a decade earlier. But Bob sought a more general solution, a machine that could build any truss efficiently. In 1982, Bob began experimenting with a roller, determined to improve upon its shortcomings, especially the quality of its plate embedment.

This “boutique” method of innovation – ideas conceived in component plants and executed in local machine shops – was the norm through much of the first turbulent 30 years of our history. That we machinery suppliers didn’t innovate is best explained by the severity of the cycles shown in the chart [See PDF or View in Full Issue]. Twice in the 1970s, we contracted to build a new plant during a runup in housing, and twice we moved in during the middle of a down cycle.

Another reason for our reticence to build a gantry was our substantial investment in hydraulic presses. Most of our customers were users of our equipment and, like Heart Truss, didn’t come to us asking for roller gantries. In addition, the Sanford gantry was a straightforward mechanism, and, once it lost patent protection, was easily replicated. Even a self-proclaimed “dumb welder” like the late Ronnie Wright could build them, one at a time, successfully.

One of Bob LePoire’s and Heart’s chief concerns was the quality of plate embedment. We had previously determined that a truss built with a 16” roller was significantly weaker than one hydraulically pressed (see Part V of this series, “The Gantry Gains Ground”), and the TPI design standard had codified this. Bob reasoned that a roller with a larger diameter would produce a much flatter angle of attack when engaging a truss plate [for diagram, See PDF or View in Full Issue]. When he tested a roller built of 24” heavy duty pipe, he found that plate embedment was greatly improved. In addition, the weight and the resulting momentum of the roller was more than doubled. This insured that even the larger and thicker gauge plates required by higher snow loads in the North wouldn’t bog down either the gantry or the finish roller.

Since the larger and heavier roller required a stronger support structure, Bob substituted a welded structure in place of Sanford’s casting. This insured longevity. In 1985, Heart installed their first LePoire-designed gantry and proved its value over a considerable period. And by 1989, Bob left Heart and staked his future on the success of his gantry improvements by launching his own company, Diamond Machinery.

At about the same time, freed of patent concerns, other manufacturers developed their own roller gantries, with improved features. Both Klaisler and Pacific Automation sought to mitigate the trip hazard of the gantry’s rail by moving it beneath the tables [See PDF or View in Full Issue]. This works great with a solid table but does not remove the hazard on walk-through tables.

These improvements increased the gantry’s market share, but its dominance awaited further innovation. At BCMC 1988 in Nashville, Alpine previewed an automated setup on its Sanford Roll-A-Master that would eventually rock the truss world. But its wide adoption was forestalled by the tanking economy. Then finally, in the early 1990s, truss demand began its steady ascent, paving the way for further gantry improvements. Recognizing the gantry’s ascendancy, we purchased Bob LePoire’s Diamond Machinery in 1994, and largely left behind our hydraulic history.

Next Month:

 Gantries Running Off the Rails

You're reading an article from the May 2020 issue.

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