sorensen-engineered-systems HOME   I   ABOUT US   I   NEWS   I   SITE MAP   I   CONTACT   I   REQUEST QUOTE   


    < Back to Custom Systems 



Two of the control locations are the East and West pushbutton stations, which can raise, lower, and initiate an emergency stop.


The master control panel is in the Harbormaster's office, which can raise, lower, and initiate emergency stop plus raise the East or West span individually.


In the event of a power failure the system is designed so that both lifting cylinders on the spans will hydraulically lock in place via counterbalance valves.


Historic Ogunquit, ME, Footbridge
At Perkin's Cove Gets Makeover

Tourists to historic Ogunquit, ME, have turned the Perkin's Cove footbridge into one of the most photographed scenes in this vacation Mecca. Tourists can't wait to look at the bridge; walk on the bridge; take pictures of the bridge and especially to push the Button on the bridge that lifts it up and out of the way for passing boats. While the Harbormaster generally controls all the activity on the bridge, the occasional tourist gets to be the "button-pusher" when a boat Captain hails for a "little help."

Since the turn of the Century one type of bridge or span or another has been in place to help people cross over what today is known as Perkin's Cove. Earlier bridges met a variety of fates including being completely washed out as a result of violent storms. If the government wasn't taking it down because it interfered with water traffic, the government was having it upgraded, the most recent time about 10 years ago.

Sorensen Systems engineers designed and installed an updated system to permit the bridge to operate efficiently and reliably. The system is designed to raise and lower both the east and west bascules of the footbridge. There is a dedicated hydraulic power unit to control the opening and closing of each bascule of the footbridge. Each span is raised in the retract motion and lowered in the extend motion of one hydraulic cylinder. The two spans, east and west, are locked in place in the down position via two hydraulic cylinders, both located on the east span, to minimize bounce and deflection at the center of the bridge.

Control of the bridge spans can take place from any of three locations. First, the Harbormaster's office, which has the Raise, Lower, and Emergency-Stop buttons, also has the capability to select either the East or West spans individually with the Power Selection switch. The other two control stations are known as the East pushbutton station and the West pushbutton station. They only have the Raise, Lower, and Emergency-Stop pushbuttons. These are accessible to passing tourists.

The design of the system includes some indicator lights to maintain control of various situations. The spans are not allowed to move unless both span lock cylinders are retracted, both east and west mechanical room access hatches are closed, no motion can be detected by sensors on either bascule, and the hydraulic power unit oil level and temperature are within operating limits. With all conditions in go mode, the bridge can then be raised.

In the event of a power failure the system is designed so that both lifting cylinders on the spans will hydraulically lock in place via counterbalance valves.

For normal operations, opening the footbridge spans is accomplished by depressing an Open pushbutton at one of the two pushbutton stations or at the Harbormaster's control panel. Once the button is depressed, and all the safety indicators are met, the PLC (programmable logic controller) will the start the Hydraulic Power Unit, sound an audible alarm, illuminate warning beacons, and initiate an eight (8) second time delay before moving the spans.

When the time delay is met, the PLC will energize the solenoid on the directional control valve to retract the span lock cylinders. Once these cylinders have been retracted and their proximity sensors tripped the lift cylinders will begin to actuate slowly, move into high speed and then return to slow speed until the spans are fully raised.

The footbridge does not operate during the winter months. The hydraulic/electrical control system was designed to operate in ambient temperatures ranging from 40 to 100 degrees Fahrenheit. As a seasonal attraction, the footbridge system's hydraulic power unit utilizes an in-tank immersion heater with thermostat to maintain a 70 degree Fahrenheit oil temperature during the seasonal usage period. The Harbormaster can leave it in the upright position or retracted, as preferred.




Sorensen Systems

A Subsidiary of THG Corporation
70 Bearfoot Road
Northborough, MA 01532

T: 508-393-7660
F: 508-393-6042


  Who Knew that Pink
Meant Hydraulics?

When the specification said the machine was to be painted pink, who knew there was more than one pink? Pink Hydraulic Power Units

  Read Mike's Best
Online Tool Links

Our VP of Engineering has some
favorite online conversion tools
that you may find useful.
Mike's Conversion Tools
  Our Engineers Comment
On Topics of Interest

Each month our engineers take up a topic and add their insight. It can range from motion control to electricity cost. Sorensen Blog.
  Sorensen Engineered Systems
Division of Sorensen Systems

70 Bearfoot Road
Northborough, MA 01532

  Phone: 508-393-7660
Fax: 508-393-8203
Email • Terms & Conditions • Disclaimer • Jobs • Our Mission
© 2018, Sorensen Systems. All rights reserved