Ball Screw Assembly for Talk Show Set

Set Movement on an Afternoon Talk Show with Specially Configured Nook Ball Screws

With its reputation as a leader in the development of theatrical, entertainment, and studio systems, Chicago Scenic Studios, Inc. (CSSI), was the natural choice to work on a highly innovative broadcast set for an afternoon talk show shot in Chicago, Illinois. The one-of-a-kind, cutting-edge set contains nearly 50 points of motion in all.

The set breaks new ground in many ways and provides for multiple ways to reveal guests, bands, or special sets. A series of mechanized devices supports numerous stage configurations, provides great flexibility, and exhibits a striking appearance. According to Mark Ewing, CSSI head of automation, the trailblazing set design included some engineering and construction challenges, including the development of a system for vertically lifting and retracting transparent, 300-pound acrylic walls, which contain light boxes, within the top portion of the walls so they can be hoisted away from the set with rigging.

"The walls are 16-feet high, and the studio ceiling is 30-feet high," Ewing explains. "We needed a means for cutting the height of the wall in half by lifting and retracting the lower portion inside the upper portion so the collapsed eight-foot wall could be removed from or brought onto the set. We needed to achieve this movement relatively quickly, to facilitate fast set changes, and quietly. We were also working with frosted Plexiglas with double-sided light boxes that you can see through and needed to hide the linear motion control system in the side of the upper wall in a space that only provided a few inches in which to work."

Because CSSI had used linear motion systems from Nook Industries in the past, the company turned to Nook to provide a customized, uniquely configured solution to this highly specialized challenge. "We knew from experience that Nook had the engineering expertise we needed to solve this problem."

Supporting eight feet of travel in a small footprint

In order to meet the challenge of lifting 300-pound walls a distance of eight feet quickly, quietly, and within a small footprint, Nook proposed specially reconfigured 50 mm ball screws that are mounted in the sides of the upper wall. The system uses an AC motor, which drives a miter gearbox to turn the ball screws, raising the ball nut on the lower wall, and lifting the wall.

"There were not any standard systems that could accommodate an eight-foot travel length in such a small space," Ewing points out. "Nook provided us with specially configured ball screws having a custom length and diameter, and provided an effective solution."

Fast, vibration-free operation

In addition to the travel length and footprint challenges, the retractable wall system had to move the wall at a rate of six-inches-per-second without creating any excess noise, resonance, or vibration. Because the walls needed to retract while other portions of the broadcast set were in use, the retractions had to be relatively quiet and vibration-free.

"The solution the Nook engineers provided was to increase the diameter of the lead screws and use a steep pitch thread pattern," Ewing recalls. "The steep thread pitch gave us the speed we needed, and by using an oversized 50 mm shaft, the Nook engineers made sure the screw would not vibrate or resonate while turning. Nook worked with us to provide lead screws that addressed all of our technical issues."

Turning a customized solution around quickly

Because the talk show set project was on a tight development timeline, obtaining a solution to the retractable wall challenge quickly was of critical importance to CSSI's success. "We had no time for trial and error or trying different prototypes of possible systems," Ewing stresses. "We needed something that worked out of the box and had zero margin for error."

"We turned to Nook Industries because we had confidence in their engineering expertise and ability to come through for us, "Ewing adds. "Nook's responsiveness contributed to the on-time, on-budget delivery of this sophisticated, technically challenging project."

Metrics

• Lifted 300-pound set walls over a travel length of eight feet.
• Dampened vibration and resonance with 50 mm diameter lead screws.
• Achieved six-inches-per-second lift speed with steep pitch thread pattern.
• Contributed to delivery of industry-leading set on-time and on-budget.