The design uses a aluminum square tubing to
form a frame that is attached to the front
carry through, and down along the seat to
the main gear channel.
The frame has a hole in it to allow a push
rod to go back to a torque arm. on the flap
torque tube. .
The assembly is held together by closely spaced
machine screws so that it can be disassembled.
The lever has a thumb button on the end that
when pressed releases the lever to be moved.
The force applied to move the flap puts load
on the center of the torgue tube and thus onto
the middle of the rear carry through, so framing
is added between the seat frame and the carry
through to resist that load.
I suspect, but haven't done the calculations
that I've saved a few pounds, and a lot of
dollars.