The A-Frame assembly consists of foldout support legs that allow the vehicle to be leveled
and stabilized for bridge deployment and an upper beam that supports the launch frame. This
upper beam is used in its lower position for launch beam deployment and is raised to provide
clearance for the modular bridge sections during bridge deployment.
The operation of the drive mechanism, winches and hydraulic cylinders is controlled via the
chest pack. The operator of the chest pack controls the whole bridge deployment operation,
which relies on coordinated actions of the 8-man crew in order to achieve minimum deployment
1-10 DETAILED DESCRIPTIONS
Power Take Off (PTO) and Hydraulic Pump
A pump provides the hydraulic power to operate the equipment services. The pump powers
the bridging hydraulic circuits and the crane services from a power take-off on the vehicle
The pump is a Standard A11VO75 variable displacement swash plate piston pump driven
via a power take-off (PTO) and drive shaft from the vehicle transmission.
The pump weighs approximately 132 lb. (60 kg) and can produce a flow of 26.4 to 31.68
US gallons (100 to 120 liters) per minute at a pressure of 4423 Psi (30495.51 kPa). It contains
pressure cut-off and load sensing control facilities, which match the flow and pressure outputs of
the pump to the service required. When no services are being selected, the pump reverts to an
idling pressure of 294 Psi (2027.05 kPa) which reduces pump and other hydraulic component
wear and extends their working life.
Cross connection is provided to allow another suitable hydraulic system to be connected to
the DSB Launcher system in the event of a pump failure due to pump or prime mover failure. This
allows the Launcher to complete its mission at a lower speed.
The cross connection system is designed to use the donor vehicle hydraulic system to
drive the DSB without interchanging fluid and the risk of overfilling one or the other reservoirs due
to cylinder motion. It also intensifies the pressure to allow the crane to lift the maximum even if
the donor vehicle does not give sufficient pressure.
It works by having a hydraulic motor driven by the hydraulic system of the donor vehicle
driving a hydraulic pump that works off the DSB hydraulic reservoir.
The crane system is used to transfer the launch beam and bridging modules from their
transportation vehicles to the launcher vehicle during bridging operations. The system comprises
an Atlas 390.1 LM Plus crane, a launch beam lifter for the launch beam modules and a two-
position bridge module lifter for use with the bridging modules.