Launch Chest Pack Umbilical Cable

TM 5-5420-279-23

cold environment operation and an hour meter to record the equipment time in use for reliability

purposes.

Mounted externally on the control cabinet are five multi-pin military style bayonet

connectors, which are routed via electrical cables to the valves, manifolds and indicators as

required by their vehicular position. The connectors are utilized for the circuitry of electrical power

in the umbilical control cable, the chassis components (filters, indicators), A-Frame equipment

(four proportional solenoids) and the launching equipment (six proportional solenoids and 11

switching solenoids).

Monitoring and fault finding of the electrical system and fault determination, whether

hydraulic or electrical, is provided within the cabinet from a mimic front panel. The panel is only

visible with the cabinet lid removed and displays the solenoids energized, chest pack lights

energized and the inputs from the chest pack. Electrical test points are provided to monitor

voltages and currents as an aid to problem identification.

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Launch Chest Pack Umbilical Cable

The umbilical cable is a 50 ft (15 m) length of multi-core cable with military connectors at each

end, which links the launch chest pack to the electrical control cabinet. It can be connected

directly to one of two remote connectors fitted to the stabilizer legs. The wiring is reversible

enabling either end connector to be used at the electrical control cabinet or the chest pack.

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Launch Chest Pack

The chest pack interfaces between the crew and the hydraulic system during launch beam

and bridge deployment and recovery. The pack is of aluminum alloy or RFI compatible plastic

construction and is attached to a breast plate carried by the crew member. It is supported on the

crew member by shoulder straps and linked to the electrical control cabinet via the umbilical

cable.

It contains a control joystick, a tilt roller/stow articulator control switch, a display screen, an

emergency stop button and voltage control circuitry. The joystick, switch and display screen are

protected from inadvertent operation and damage by a guard.

Movement of the joystick to the right or left selects the function and up and down

movement controls the direction and speed of the function selected. The joystick has cross (+)

function which permits only one action to take place at a time (i.e. select a new function or carry

out the previously selected function).

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