TM5-3810-305-10General Theory of OperationThe LRT 110 Crane is a self-contained vehiclefeaturing 7 1/2 ton maximum lifting capacity,optional four-wheel drive, outriggers for addedstability during lifting operations and threedifferent steering modes: front wheel steeringfor normal driving, crab steering for diagonalmoves and four-wheel steering for minimum-radius turns.Power originates from an in-line, four-cylinder,diesel engine mounted at the rear of the vehicle.The transmission is mounted directly on theengine and is used to turn drive shafts and topower the tandem hydraulic pump. One-half ofthe tandem hydraulic pump supplies hydraulicpressure to the winch, and the other half supplieshydraulic pressure to actuate the boom telescopecylinder, boom hoist cylinder, boom swingmotor, outrigger cylinders, axle lockout cylindersand steering controls, and to provide hydraulicassistance for the brake system.The boom is a two-section telescope-type with arotating boom support. Two large-diameter,double-acting hydraulic cylinders telescope andhoist the boom assembly. The hydraulic swingmotor and worm gear rotate the upperstructure.The cable and hook block assembly are operatedby the hydraulic winch. The hydraulic andelectrical systems on the upperstructure are con-nected to the rest of the vehicle by the hydraulicrotary manifold and electrical collector ring.TransmissionTheoryofOperationThe transmission is capable of four-speed shift-ing in both forward and reverse. Direction andspeed are selected through hydraulically actuatedmultiple-disc clutches. The clutches are powerabsorbing, allowing shifts under full enginepower in both forward and reverse. The clutchesare hydraulically controlled and spring released.Hydraulic control makes the clutches self-adjusting. Each clutch is made of friction platesand polished-steel reaction plates.The transmission receives power from the enginethrough the torque converter. The torque con-verter is fluid driven, creating a smooth andshock-free drive. Fluid drive also eliminatesengine stalling and lugging when vehicle has aheavy load. With light loads, the torque con-verter is able to transmit engine power directly tothe transmission at most engine speeds with notorque multiplication. This provides variable andautomatic speed ratios, reducing need for shiftinggears.Axle Theory of OperationThe front and rear axles have remote breathers toallow operation in up to 30 in. (762 mm) ofwater. The rear axle has lockout cylinders toprovide increased stability during hoisting.Steering for each axle is enhanced by dual-actinghydraulic cylinders which are tied together by asingle tie rod which provides smooth, sharp,synchronized turning with minimum alignmentand adjustment requirements. The service brakesare shoe-type hydraulic units, and are part of theaxle. The front axle has a disc brake that can beused either as a parking brake or as an emer-gency brake. Each axle has its own differential.3-2
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