In an application where the overhead door closes on top of the lowered dock lift platform it is common to order the dock lift equipped with an optional Overhead Door Kit.
The Overhead Door Kit prevents the dock attendant from accidentally attempting to raise the dock lift when the overhead door is in the closed /locked position on top of the lowered dock lift platform. Attempting to raise the dock lift with the overhead door closed / locked could cause damage to the overhead door.
The Overhead Door Kit consists of a limit switch, a wall mounting bracket, an overhead door actuator bracket and the dock lift power unit control panel is pre-wired to accept the limit switch wiring.
The limit switch and mounting bracket are installed on the interior wall adjacent to the overhead door track typically approximately 6’ – 8’ above the finished floor level. The actuator bracket is installed on the inside of the overhead door, typically towards the bottom of the door.
With the overhead door in the lowered/closed position the wall installed limit switch is wired open circuit interrupting the electrical signal from the dock lift control station “up” button to the power unit.
When the overhead door is raised the door installed actuator bracket activates the wall installed limit switch closing the electrical circuit to the dock lift control station: the dock lift is now operational.
In summary the Overhead Door Kit prevents the dock lift from operating until the overhead door is open. This prevents possible damage to the overhead door caused by the dock attendant operating the dock lift when the overhead door is in the lowered/closed position.
This link leads to a photograph of an Overhead Door Interlock Kit. https://www.pentalift.com/solutions/electrical-options-overhead-door-kit/
For additional information on any Pentalift product please contact the Pentalift Sales Department.