Purkeys has partnered with Silver Eagle Manufacturing to give additional capability and reliability to Silver Eagle’s new adjustable trailer dolly.
According to the companies, Silver Eagle’s new T-Dolly automatically telescopes and retracts to adjust the gap between trailers based on the information received by the control module Purkeys designed. It also is said to allow the gap between trailers to be decreased at highway speeds to improve tracking and fuel economy.
“The people at Silver Eagle recognized that having an electronic controller would improve their T-Dolly,” Purkeys’ Chief Engineer Dale Henningson says. “Purkeys’ expertise is in electronic controllers so we were a good fit for partnering up with them on this project.”
Henningson says the control module was designed to perform two main functions: control the distance between trailers and charge the battery.
Purkeys’ control module relies on speed sensors to provide feedback on whether the dolly needs to be extended or retracted. Once the vehicle reaches 45 mph, an electro-hydraulic pump pulls the trailers closer together. When the speed slows to 40 mph and below, the T-Dolly increases the gap and allows the vehicle to make turns safely. To prevent gap adjustments at unnecessary times, the companies says the control module has certain parameters programmed that must be met before the T-Dolly will retract or expand. There also is a safety feature installed that will automatically return the trailers to the extended position if any one of several errors are detected. A service light will then flash to indicate the problem and allow for troubleshooting, the companies say.
According to Gary Gaussoin, president of Silver Eagle Manufacturing, supplying power to the electro-hydraulic pump presented some issues for the T-Dolly design.
“It’s well known that power from the 7-way is not always constant and when you have combination trailers, you can get a big voltage drop,” Gaussoin says.
Purkeys worked with Silver Eagle Manufacturing to improve this issue. Knowing that the 7-way voltage is not always the most reliable power source, Purkeys says its used a DC/DC converter to boost the voltage from the 7-way and keep the hydraulic pump battery charged.
Purkeys and Silver Eage note adjusting the gap between trailers allows fleets to improve vehicle stability and fuel efficiency while allowing drivers to make turns safely at low speeds. The logic provided by the control module and the safety features ensure the adjustable T-Dolly works properly without jeopardizing the truck batteries, the companies say.
