Thern is excited to share the details of a recent project that was completed in conjunction with S.A.F.E Structure Designs, a global leader in the design and manufacturing of custom equipment that provides innovative, ergonomic, safe, maintenance equipment to civilian and military sectors.

S.A.F.E Structure Designs approached Thern with an application that required a winch that could lift and lower a raised platform or walkway, often known as a gangway, from land onto a ship. The winch needed to be pneumatically powered with an option to manually operate the winch in the event of power loss. Additionally, the gangway would be left deployed overnight and due to changing tides, the height of the ship would rise and fall. To accommodate this requirement, the winch needed to automatically compensate for change in height to prevent injuries or damage to the ship or landing structure.

Presented with an aggressive timeline to design, manufacture, test and deliver the system; Thern worked closely with S.A.F.E Structure Designs develop a solution. Thern’s engineering team researched the requirements of the application, ultimately developing a custom dual drum, pneumatically actuated, winch with load sensing controls. S.A.F.E Structure Designs in turn provided the completed solution, incorporating Thern’s winch with mounting structure and mated the winch to the gangway support.

The Thern solution was designed and built to operate in 3 completely different conditions to flawlessly integrate into the S.A.F.E Structure Designs turnkey solution:

1. Pneumatic (air) power – The winch was designed to be capable of lifting and lowering the gangway utilizing a pneumatic motor and brake.

2. Manually operated – A clutch was included that, when activated, locks out the ability to pneumatically power the winch. When the clutch is engaged, it attaches the drivetrain to a manual hand crank, positioned at operator level for emergency lifting or lowering. The hand crank also includes a brake for load control.

3. Gravity powered – This was required to allow for the winch to adjust unattended to accommodate overnight changes in tides. The winch is equipped with an option to allow the load to drift up or down in a controlled manner. There are strict requirements for this operating condition, specifically, the load would need to be supported by something other than the winch before switching to gravity power. No personnel are allowed on the gangway during this operating condition. The pneumatic power is removed and the emergency hand crank clutch is disengaged. All brakes on the unit are released. The winch then allows the load to adjust in a controlled manner, should the tides lower the vessel overnight ensuring the gangway stays in contact with the vessel. Large headache balls were added to the wire ropes attaching the winch to the gangway to take up slack should the tides raise the vessel overnight.

Do you have a problem with no solution? Thern has been creating custom made winches and products for 70 years and is happy to take on challenging applications. Contact Thern today, and leave the heavy lifting to us.

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