models, the stair treads, intermediate platform, and upper platform are surfaced
with aluminum alloy diamond-plate treads. Rubber treads over aluminum alloy
surfaces can be supplied as an alternate to the diamond plate.
1.4.11 Main Section (Stationary Unit)
The main stair unit is built on a frame of structural steel channels. Side panels of
fabricated sheet aluminum are riveted to this frame. Two wheels are attached on
each side of the upper part of the frame. The adjustable section's main
longitudinal support channels ride over these wheels to provide the telescoping
feature.
The lowest step (flip step) is mounted on pivots between the side panels. This
step may be flipped up between the side panels to allow sufficient ground
clearance when moving the stair. There are fourteen step treads in the main
section. The uppermost tread plate is deeper and serves as an intermediate
platform between the main section and the adjustable section.
Installed within the main section is a positive-displacement single-acting hydraulic
cylinder. This cylinder is attached to a cross member at its lower end, and the
upper end attaches to the adjustable section. This is the lift cylinder that
hydraulically adjusts the stair section.
1.4.12 Adjustable Section (Telescoping Unit)
The adjustable stair unit is built on a welded-steel frame composed of two
parallel/longitudinal channel members. The open sides of the channels oppose
each other and telescope over the four support wheels attached to the main
section. Steel angles welded to the underside of the channels are notched in
such a way that when solenoid-actuated latches are engaged in the notches, the
section is precisely positioned for any of ten stair heights (See operation
instruction). There are ten steps.
The top platform is a riveted assembly of aluminum alloy components. It is
supported by two fabricated channel members installed longitudinally. On the aft
end of the platform, a steel cross member is attached to these supports. This
cross member has a lug on its aft side to which the upper end of the hydraulic lift
cylinder is attached. When hydraulic power is applied to the cylinder, a piston
extends the adjustable stair section. A neoprene rubber bumper is attached to
the forward edge of the platform to protect aircraft.
Movable handrails are on either side of the top platform. These are adjustable
fore and aft and can be locked in position. The forward edges of these panels are
padded to protect aircraft.
SEPTEMBER 30, 2008
CHAPTER 1 GENERAL INFORMATION & OPERATION INSTRUCTIONS
PAGE 8
1 DESCRIPTION
Truck Mounted Passenger Stair TMPS-200
Manual No. 307559
