Caterpillar P-5000 Power Loader Production information Manufacturer Caterpillar/Weyland Corp Technical specifications Power plant Hydrogen fuel cell Armament Small torch Crew 1 Usage Role(s) Cargo transport Counterpart(s) Exosuit Affiliation USCM, Commercial use
	[Source]

The Caterpillar P-5000 Powered Work Loader, commonly referred to as a Power Loader, is a commercial mechanized exoskeleton used for lifting heavy materials and objects. As well as widespread industrial use, the P-5000 is heavily employed by the United States Colonial Marine Corps to load ordnance on board their starships.^[1] Power loaders are equipped with hydraulic "claws" than can be used to hold and manipulate a variety of objects.

The Colonial Marines (as well as other groups, including the Iron Bears) also utilize a weaponized exoskeleton based on the P-5000 as part of their space arsenal. Perhaps the most famous use of a Power Loader was when Ellen Ripley used one in desperation to engage a Xenomorph Queen in hand-to-hand combat aboard the USS Sulaco.

Contents 1 Summary 1.1 Weyland Corp 2 Hydraulics 3 Operation 4 Behind the scenes 5 Appearances 6 References

SummaryEdit

The Caterpillar P-5000 Loader was selected by the Colonial Marines as their prime loader vehicle for logistic and support operations. Configured as an anthropomorphic exoskeleton power frame, the P-5000 offers unprecedented flexibility when handling ordinance and cargo during rough field operations or when conducting heavy maintenance away from fixed workshops. Capable of fine manipulation of loads up to 4000 kg, the P-5000 is a rugged and reliable alternative to conventional forklifts, rigs and cranes.

The Loader's claws are fully adjustable, and as such can be used to grab and hold a wide variety of objects, although most common industrial storage mediums are fitted with uniform, purpose-made grips than can easily interface with the Power Loader's claws.^[1] Typically, one fork of each claw is placed under the object to be lifted while the other fork clamps down on top of the object, holding it firmly and securely in a vice-like grip.

Weyland CorpEdit

"Since introduction, the power loader has improved workplace safety by 300% in off-world applications. Its low alloy steel exoskeleton is designed to withstand maximum compression stress, keeping the driver safe from external blows. Hydraulically stabilized legs give 3 tons of load lifting ability."

HydraulicsEdit

The chassis of a P-5000 is a reinforced steel framework with two upper load bearing points for the arms. A

hydrogen fuel cell is mounted on the back of the frame, providing up to 65 kW of power for the loader. The articulated legs are attached by two semi-universal bearings to either side of the chassis, allowing up to 60 degrees of 'x' axis (hip swivel) movement; just below these are a set of knee bearings. Leg motions at the hip are controlled by a pair of 20kW linear motors actuated via a fast-feedback loop slaved to the operator’s movements. Below the hip, hydraulic actuators extend from the main load-bearing points to the aft sections of the legs, providing 'z' axis (fore/aft) movement at the knee joints while pitch control is handled by a second series of actuators at the ankles. To prevent toppling while stationary and under load, the chassis is gyrostabilized. These gyros can be rotated rapidly out of phase in order to 'decouple' the chassis stabilization system along the determined axes of motion and provide the necessary instability required for bipedal movement. For very heavy lifting work, additional stability can be provided by bolting up to 250 kg of concrete ballast to the underside of the chassis.

OperationEdit

To work a powerloader, an operator first backs into the machine, buckling themselves in with the webbing harness. A roll cage is pulled down to provide protection for the head and torso, while feet are snapped into straps. Powerup and system diagnostics are handled by a punch keypad built into the operator's handgrips. There are also controls to operate a built in welder on the control panel. When powered up, the 'loader' is slaved to the operator's limb movements, duplicating their walking and lifting motions almost exactly. Response time to operator input is almost instantaneous, while sophisticated computer controls dampen any system induced 'twitches' or oscillations that arise out of involuntary operator movement. Problems are only likely to arise if the loader is walking or reaching at full extension, as the system is likely to enhance movement beyond the fine-tuning capabilities of the operator. Standard operating procedures usually forbid operators from performing such maneuvers. If operating over rough ground, the powerloader will provide feedback cues to the operator to help keep his or her footing. Automatic lockout systems will generally prevent any movement that will topple the 'loader', and the system has generally proved safe to use over all but the most treacherous terrain. It must be noted that there are strict guidelines for weight limits that the loader can handle and failure to adhere to these can cause the 'loader' to topple.

Though simple in principle, considerable practice is required to use a powerloader efficiently and safely, and the equivalent of a Class 2 civilian cargo handling license is needed to operate in USCM service. Operators must become used to the loaders mass and its tendency to 'lead' the operators movements. Operators must be careful not to overcompensate for this tendency, otherwise they may induce unwanted oscillations into the control systems. To operate a 'loader' requires sureness and economy of movement, since hesitancy and exaggerated motion tend to place undue stress on the load-bearing joints. Training to use a power loader takes about six weeks in a simulator and 'hands-on' experience, though this is extended to eight weeks to qualify USCM personnel and includes training in rough field operation.

Behind the scenesEdit

The Power Loader in Aliens was a full-scale prop constructed around stuntman John Lees, who was concealed inside, immediately behind Sigourney Weaver.^[2] The suit featured electrically-operated claws, although the various hydraulic systems were cosmetic only. The tandem design allowed Sigourney Weaver to be in the operator's seat at all times, while Lees controlled the suit from within. Owing to it's weight and bulk, the suit was either suspended from wires (concealed within the radio antennae on the suit's shoulders) or mounted on a counterbalanced crane.^[2] Additionally, a scale miniature was used for some shots, including wide shots during the fight with the Queen and the scene where the suit is ejected into space, for which the camera was hung vertically and the suit was dropped away onto a safety net painted to resemble space.^[2]

A new weaponized version of the Power Loader was set to appear in Aliens: Colonial Marines and was featured in the E3 demonstration of the game; it was essentially a standard P-5000 outfitted with an M56 Smartgun fitted to one arm and an M240 Incinerator Unit on the other. However, it was cut from the final product. Although not specified, it seems likely this exoskeleton was not supposed to be purpose-built military equipment, but merely an ad hoc combat exosuit constructed by the Marines from existing commercial equipment and their own weaponry.

AppearancesEdit

• Aliens/novel (First Appearance)
• Alien vs. Predator (video game)
• Aliens: Colonial Marines (video game)

ReferencesEdit

1. ↑ ^{1.0 1.1} James Cameron (writer and director). Aliens [DVD]. 20th Century Fox.
2. ↑ ^{2.0 2.1 2.2} James Cameron, Gale Anne Hurd, Gordon Carroll, David Giler, Walter Hill, Stan Winston. Superior Firepower: The Making of 'Aliens' [DVD]. 20th Century Fox.

• http://colonialmarines.wikispaces.com/Vehicles