A subsurface aircraft servicing pit is provided with a hold down assembly
that secures a pit lid mounting frame in position on a bearing seat at
the top of a prefabricated pit enclosure. A frame mount latch ring is
suspended in spaced relation beneath the underside of the pit lid
mounting frame and inwardly from the walls of the pit enclosure. At least
a pair of frame mount latches are provided on opposite sides of the pit.
The latches have bases secured to the pit walls and hooks that extend
over the top of the frame mount latch ring. The frame mount latches are
constructed so as to exert a downward force on the frame mount latch
ring, thus holding the peripheral margin of the pit lid mounting frame
tightly against a peripheral bearing seat surrounding the pit opening.
The necessary force exerted by the frame mount latches may be provided by
a coil spring located within the structure of each frame mount latch.