When Turner Hydraulics was contacted to work on the Phillies Liberty Bell in Citizens Bank Park in Philadelphia, they along with their automation division, TASCorp, were excited to help them improve the operation of the bell. Read about it here in the cover story for Fluid Power World, one of the leading magazines for the fluid power industry.

From the Article:

A group of about a dozen limit switches were designed to know the position of the bell, so that when it was turned on, a limit switch would know to stop and go back and swing backwards, said Andrew Roach, Project Manager for Ballpark Renovations.

“Birds would sit on the limit switches, believe it or not. And, then, they would get knocked out of whack and then the bell really didn’t know where its current position was,” Roach said. “Then, it would think it was at the end, so it wouldn’t move, or it would be stopped in the middle and then it wouldn’t move when we would hit the button.”

After working with Turner Hydraulics/TASCorp. and the köllab group, the Phillies’ Liberty Bell swings and chimes better than it has ever done, with modernized lighting and controls. Image courtesy of The Phillies/Miles Kennedy

So, as the season wrapped up in 2021, Roach’s team reached out to Tyler Kicera, of köllab group, who is an expert in designing kinetic motion systems for entertainment purposes, to assess the situation and determine what steps should be taken to revamp the bell’s control system.

“We didn’t deviate too far from the original. In my mind I wanted to figure out how we could build in some additional range of motion in terms of speed and functionality. The main method of how the Liberty Bell moves is through hydraulics,” Kicera said. “Looking at that system, it had been upgraded and different pieces and parts added onto over the years. It was sort of cobbled together. And, obviously, from my time in the entertainment industry, I knew what was possible from that perspective and how to clean it up and make it more efficient and sort of just bring it up to the current technology.

“So that was ultimately the driving force — to restore the speed and range of motion, as well as just making it something that was bulletproof and was going to work when they hit the Go button.”

It was soon realized that the current company that was charged with maintaining the hydraulics system would not be able to update the system as Kicera envisioned. So, he reached out to Turner Hydraulics because he had worked extensively with them in the past.

“The issue with the old bell was that there was no feedback. So you would hit, ‘Start moving.’ And the bell wouldn’t move and you would just be like, ‘Did it not get the signal? Did it get the signal and just decide not to move for some reason?’ So there was no two-way communication,” Roach said. “Now up in the control room on the wall, we have a screen that shows the current status of the bell. If we restart the HPU and reboot the computer, that shows that there’s communication back and forth between the two systems; between our touch screen on the wall, and the bell itself, and the hydraulics. So it just gives us a lot more info on what’s going on up there,” Roach concluded.
The rebuilt hydraulic power unit was more compact, as it eliminated a heat exchanger and featured a smaller motor and a new hydraulic pump, among other things. Image courtesy of Turner Hydraulics/TASCorp..

The rebuilt hydraulic power unit was more compact, as it eliminated a heat exchanger and featured a smaller motor and a new hydraulic pump, among other things. Image courtesy of Turner Hydraulics/TASCorp..

The Turner team got to work fast, focusing first on the position sensing of the system. Limit switches were able to tell when the bell was to the left and when it was to the right. They also had a slow down left, slow down right, and a center position limit switch.

“The limit switches seemed to be as much a problem as anything on the system and made it difficult to troubleshoot and get their finger on what was happening at which point,” Turner said. “And so, what we did, we took off the limit switches. We put on a linear encoder, like an LVDT. And, therefore, we were able to tell the bell’s position no matter where it was at. With the limit switches, you didn’t know where the bell was until it tripped one of the limit switches.

“And the clapper had very much the same system of limit switches. So, on the tower, there were probably 10 different limits switches which we removed, and then we put on just two of the LVDTs, one for the bell and one for the clapper.”