DT50-55 Tech Manual.pdf

Technical MANUAL

Double Taper Crane

DT50-55

S/n 2003

MANUFACTURED BY

SHERWOOD, OR U.S.A.

80-677A 1 July 2001 i

SAFETY SUMMARY

GENERAL SAFETY NOTICES

Summarized on the following pages are general safety notices which supplement specific warnings and cautions appearing elsewhere in this manual. Since all electrical and hydraulic equipment is dangerous when operated or maintained incorrectly, thoroughly review and understand the Safety Summary before attempting to operate, troubleshoot or service this crane.

The following symbols/terms are used to emphasize safety precautions and notices in this manual:

The “warning” symbol appears wherever incorrect operating procedures or practices could cause serious injury or death. Carefully read the message that follows to prevent serious injury or death.

CAUTION

The “caution” symbol appears wherever incorrect operating procedures or practices could cause damage to equipment. Carefully read the message that follows to prevent equipment damage.

NOTE: …

The term “NOTE” highlights operating procedures or practices that may improve equipment reliability and/or personnel performance.

NOTE: All possible safety hazards cannot be foreseen so as to be included in this manual.

Therefore, you must always be alert to potential hazards that could endanger personnel and/or damage the equipment.

Capacities shown in this manual make no allowances for factors such as freely suspended loads, operating speeds or weights of accessories.

OPERATING SAFETY

Qualifications This crane must be operated and maintained by experienced, trained personnel. You must receive training prior to operating this crane.

If you do not routinely operate this crane, refresher training is recommended. You must reacquaint yourself with this manual and the equipment before starting, then proceed slowly.

Safety Clothing Always wear appropriate safety clothing and use prescribed saftey equipment - head, foot, hand and eye protection may be required.

Do Not Operate Alone It is essential that someone be on deck to watch clearances and give hand signals. Ensure that the director is clear of the crane and the load before you move it. Do not move the crane or load if you cannot see this person.

Equipment Hazards Do not operate this crane if you know of malfunctions, missing parts, and/or misadjustments. Any one of these situations can cause or contribute to an accident or damage the crane. Lower the load and stop the crane immediately if problems arise after starting.

Do not start the hydraulic power unit if the “start” switch has been tagged-out with a “DO NOT START” or other red tag.

Never allow anyone under a suspended load. Ensure the area is clear before moving the crane or load.

Never attempt any lifting operation with fewer than five wraps of cable on the winch drum. Cable clamps are not designed to hold loads.

Never attempt to dismantle any of the safety devices built into the crane.

When swinging the boom, always ensure that there is adequate clearance for both the boom and the load.

Do not overload the crane. Always operate within the rated capacity of the crane and rigging. Refer to the load chart for this crane’s lifting capacity.

Inspect slings, chokers and other rigging devices frequently for cuts, abrasion, rust, kinks or other damage. Do not use suspected defective equipment to lift or move a load.

Always wear appropriate safety clothing and use prescribed safety equipment—head, foot, hand and eye protection, etc.

Accurately place the load, keeping in mind how you expect the load to respond when released.

Lower and remove the load before leaving the crane or securing hydraulic power.

Maintain proper clearance from energized equipment. If the crane contacts energized equipment—stay clear of the crane and prevent anyone else from coming in contact with the crane. If you are on the crane, stand fast—Do not jump off.

MAINTENANCE SAFETY

Unless properly serviced, this crane can be extremely dangerous.

Qualifications In order to ensure safety, each person working on this crane must have the necessary skills, information, tools and equipment. Do not attempt to make adjustments, or perform repairs unless you are authorized and qualified to do so.

Do Not Work Alone Never attempt to service energized equipment alone.

Someone capable of providing aid in the event of accidental shock must be present.

Do not rely on the hydraulic system to support any part of the crane during maintenance or lubrication. Never stand under a crane component that is supported only by the hydraulic system. Ensure components are resting on their mechanical stops or supported with appropriate safety stands during maintenance or lubrication.

Unless otherwise directed in this manual, never attempt servicing while power is applied. Tag the “START” switch and/or the disconnect switch with a “DO NOT START” sign when required.

Never attempt servicing while the crane is moving or the hydraulic power unit is running. Lower the load and secure power.

Equipment Safety Test Equipment. Ensure test equipment is in good condition.

If an instrument must be held while taking measurements, ground the case of the instrument before energizing equipment. Do not touch live equipment or personnel working on live equipment while holding a multimeter. Some types of measuring devices should not be grounded—do not hold such devices while taking measurements.

Heavy Equipment. Prevent personal injury or equipment damage by using a lifting device with a lifting capacity greater than twice the weight of any equipment to be lifted.

Pressurized Equipment. Wear safety goggles when working on or near pressurized equipment.

Lower all loads and relieve all hydraulic pressure before disconnecting hydraulic lines. Otherwise, the load could fall on you or pressurized hydraulic oil could cause severe personal injury. Never try to stop a hydraulic leak with any part of your body.

Electrical Hazards

An electric shock could be fatal—typically, the hydraulic power unit (HPU) is driven by a 440 vac, 3-phase, 60 Hz motor. Ensure power to the crane is “OFF” before opening electrical panels. Never attempt electrical testing or repairs while standing in water.

Remove watches, rings, or any jewelry that may contact energized circuits.

Hot Oil Hazards Burns from hot oil can be severe—Always allow lubricating and hydraulic oil to cool before draining.

Fire Hazards Hydraulic oil is flammable. Do not smoke when checking or filling the tank. Keep open flames and sparks away from the crane.

Regular steam cleaning is recommended for fire prevention and improves general safety by removing oil, and dirt accumulations.

Never overfill the hydraulic tank because the overflow could contribute to a fire. Immediately repair any hydraulic leaks and clean up spills.

Compressed Air Hazards When using compressed air to dry parts, pressure should not exceed 30 psi (200 kPa).

Air pressure penetrating your skin can be fatal. Never direct compressed air at anyone.

Falling Hazard Due to the height of some lubrication points, it is essential to personnel safety that approved ladders, personnel lifts and/or scaffolding be used while servicing this crane. Always lower the crane as far as possible before attempting to perform repairs or service.

Always use safety treads and handholds where provided. The crane can be dangerously slick whenever oily surfaces are exposed to rain or frost.

Warnings and Cautions Specific warnings, cautions and notes applicable to this equipment appear elsewhere throughout the manual. The following warnings and cautions summarize information that should be familiar to anyone operating or servicing this equipment, and are repeated here for emphasis only.

SAFETY SUMMARY

ii

Pressing ANY bypass switch places you in control of safety for that function.

Heed all other displays and alarms.

ONLY QUALIFIED PERSONNEL SHOULD perform ELECTRICAL TROUBLESHOOTing, Adjustment, AND/or REPAIR.

NEVER ADJUST HYDRAULIC COMPONENTS

BEYOND THE VALUES GIVEN IN THIS MANUAL.

ANY ATTEMPT TO GAIN “EXTRA” LIFTING

CAPACITY WILL CAUSE OVERLOADING THAT

MAY RESULT IN property DAMAGE, serious

INJURY OR DEATH.

CABLE CLAMPS ARE NOT DESIGNED TO HOLD

LOADS. NEVER attempt to hoist a load WITH

FEWER THAN FIVE COMPLETE WRAPS OF CABLE

ON THE DRUM.

Relieve load from lift cylinders, including weight of the boom, and tagout/ lockout power before disconnecting tubes and hoses. failure to heed these instructions could result in property damage, serious injury or death.

Do not reuse roll pins, seals, or O-rings.

THIS equipment IS powered by 440 VAC. ALL

ELECTRICAL CONNECTIONS MUST COMPLY WITH

APPLICABLE CODES AND/OR REGULATIONS.

IMPROPER OR INCORRECT practices COULD

RESULT IN SERIOUS INJURY OR DEATH.

Tag out/lockout Hydraulic and electrical

POWER TO THE CRANE BEFORE ATTEMPTING TO

DISCONNECT WIRES AND ELECTRICAL CABLES.

AN ELECTRIC SHOCK CAN BE FATAL.

CAUTION

Starter Box START and STOP controls are provided for service and/or emergency purposes only.

Never continue to hold control levers in the actuated position after a component has reached its travel limit. This can cause hydraulic system overheating and equipment failure.

SAFETY SUMMARY

iii/iv (Blank)

Never let control levers snap back to neutral because actuator damage may result.

If the HPU low oil indicator and/or the filter service indicator illuminates, press “Stop” and correct the condition before proceeding.

Operating temperature must not exceed 180°F. If any of the hydraulic components overheat, shut down crane as soon as safely practical, and determine the cause of overheating.

Ensure open ports, hoses, tubes and fittings are either capped or plugged during service and repair to prevent HYDRAULIC SYSTEM contamination.

Do not use organic solvents to clean O‑rings, seals or packings.

Maintain at least 100 lbs of tension on the line to Ensure cable is held tightly on the drum.

Do not run a pump on stroke against a blocked output unless A HIGH PRESSURE RELIEF VALVE PROTECTS IT and then run no longer than necessary to check leakage.

Limit discharge to prevent dropping tank level below “low” level.

Intentionally Blank

1 - 1

CHAPTER 1

GENERAL INFORMATION AND SAFETY PRECAUTIONS

1.1 SAFETY PRECAUTIONS

Warnings and cautions appearing throughout this technical manual are of paramount importance to personnel and equipment safety. Before attempting to operate, troubleshoot, or service this equipment, you must thoroughly review and understand the Safety Summary that precedes this chapter.

The following symbols/terms are used to emphasize safety precautions in this manual:

The “warning” symbol appears wherever incorrect operating procedures or practices could cause serious injury or death. Carefully read the message that follows to prevent serious injury or death.

CAUTION

The “caution” symbol appears wherever incorrect operating procedures or practices could cause damage to equipment. Carefully read the message that follows to prevent equipment damage.

NOTE:

The term “NOTE” highlights operating procedures or practices that may improve equipment reliability and/or personnel performance.

NOTE: All possible safety hazards cannot be foreseen so as to be included in this manual.

Therefore, you must always be alert to potential hazards that could endanger personnel and/or damage the equipment.

1.2 INTRODUCTION

This manual has been prepared to assist personnel operating and servicing the DT50-55 Crane. Chapters 1 through 6 comprise the operating and servicing instructions, Chapter 7 contains parts lists for all components of the crane and Chapter 8 provides installation procedures.

1.2.1 Scope

This manual provides sufficient instructions to enable personnel to accomplish the following:

Intermediate and depot level maintenance, specifically inspection, operability tests, fault isolation, and overhaul of items such as motors, brakes, and winches, will normally be accomplished at more extensive shop facilities.

1.2.2 Applicability

This manual is applicable to the Model DT50-55 Double Tapered Crane, S/N 2003

1.3 Crane Description

See Figure 1-1. The crane was developed for the deploying and retrieving boats, stores, ammunition and aircraft from a dock or barge or from the ship's deck.

1.3.1 Major Units

The pedestal, turret, and boom are the structural members that support the load. A shear ball swing bearing is bolted to the underside of the turret that is in turn bolted to a flanged pedestal welded to the ship's deck. An actuating cylinder raises and lowers the boom. Turret-mounted swing drives position the boom horizontally. The main winch, mounted atop the boom, hoists a hook block that is rigged for two-part reeving through a sheave to raise and lower the load.

1.3.1.1 Cab Control Console

All operating controls and indicators are located inside the cab that is mounted to the crane operator’s platform to the right of the turret assembly.

1.3.2 Hydraulic Power Unit

System pressure is supplied by a hydraulic power unit (HPU) with an electrical motor driven, pressure compensated, tandem axial piston, variable displacement pump delivering 38 total gpm and a 100 gallon tank. Oil returning to the tank passes through a 6 micron return filter.

1.3.1.3 Main Winch

See Figure 1-1. Powered in both directions by a fixed-displacement, hydraulic gear motor through spring applied/hydraulically released brakes and a double planetary gear reducer, an API personnel rated winch is mounted to the top side of the boom.

1 - 2

1.3.1.4 Swing Drive

See Figure 1-1. Two swing drives are mounted to the turret base to train the crane left or right. Each drive consists of a fixed-displacement, axial-piston hydraulic motor, and a triple-planetary gear reducer with a spring applied/ hydraulically released parking brake.

1.3.2 Hydraulic System

A remotely piloted control valve distributes hydraulic fluid from the driven units and the HPU. Load-sense pressure compensation is used to reduce heat buildup and resultant component wear by providing only the flow required by the system.

1-3.2.1 Control Valve The control valve distributes fluid pressure to each subsystem when the respective control levers are actuated.

Each section of the control valve forms a closed-loop with the corresponding system.

1-3.2.2 Swing System The swing system controls hydraulic pressure and return flow required for swinging the boom. Fluid pressure from the control valve sequentially releases the swing brake, and then actuates the swing motors. Dual counterbalance valves hydraulically lock the swing motors until actuated.

1-3.2.3 B oom System The boom system controls hydraulic pressure and return flow required for raising or lowering the boom. Loadlock valves on each cylinder hold loads to prevent the boom from free falling.

1-3.2.4 W inch System The winch system controls hydraulic pressure and return flow required for raising or lowering a load. The winch system consists of the Winch, control valve, and associated plumbing.

1-3.2.5 Emergency Lowering System The emergency lowering system is designed to provide a means for lowering a load in the event of a power loss.

The emergency lowering system consists of a selector valve, hand pump, pressure gauge, and a connection for a portable hydraulic power unit.

1-3.3 Electrical System Both power distribution and control functions are served by the electrical system. For this reason, the electrical system is divided into HPU and Crane Control subsystems.

1-3.3.1 HPU Electrical System The HPU is powered by a shock-mounted, 50-hp, totally enclosed fan cooled (TEFC), 440 vac/3-phase/ 60 Hz motor. This 50-hp motor is energized by a solid-state soft-start system.

1-3.3.2 Anti-Two-Block Control The Anti-Two-Block Control is designed to prevent the operator from hoisting the hook into its sheave by interrupting winch operation before the hook block or haul ball contacts the sheave.

1-3.3.3 Overload Control The Overload Control is designed to prevent the operator from moving a load to an unsafe position, or hoisting a load that exceeds the capabilities of the winch.

1.3.3.4 Load Moment Indicator System

The load moment indicator system senses load weight and provides overload protection. There is a display in the cab to keep the operator informed the weight of loads lifted by the crane.

1-4 REFERENCE DATA

1-4.1 Reference Data Chart The reference data chart (Table 1-1) contains specifications for the Boat and Aircraft Crane.

NOTE: Capacities shown in this manual make no allowances for factors such as freely suspended loads, operating speeds or weights of accessories.

1-4.2 Data Plate The data plate (identification plate) is permanently attached on the side of the turret. A data plate identifies characteristics of the equipment to which it is attached.

1 - 3

Table 1-1 Reference Data

Characteristics Description

Ratings:

Test Weights:

Main Winch

Electric Motor: 50 hp @ 1,800 rpm, 440 vac, 3-phase, 60 Hz

Main Control Valve: 3-Section, Mechanically Controlled

Boom: Double Acting—Allied Marine Crane, 10" x 75" Cylinder

1 - 4

Table 1-1 Reference Data - Continued

Characteristics Description

Swing:

Environmental:

Component Weights:

1 - 5

Figure 1-1 Dimensional Data, Double Tapered Box Boom Crane

Model............................................................ DT 50-55 Nomenclature........ Double Tapered Box Boom Crane Rated Capacity............................................ 40,000 lbs Overturn Moment.....................................951,000 lb-ft Swing Moment..........................................37,085 lb-in Crane Gross Weight................... 18,000 lbs (Approx)

NOTE: Capacities shown in this manual make no allowances for freely suspended loads, operating speeds, or weights of any accessories.

1 - 6 Figure 1-2 Hydraulic Capacity Chart

2 - 1

CHAPTER 2

OPERATION

2.1 INTRODUCTION

This chapter provides detailed information and step‑by‑step instructions for safely and effectively operating the DT50- 55 Boat and Aircraft Crane, S/N 2003. Normal operation includes moving a load from the ship deck to the water, barge or dock and vice versa. Emergency operation provides a means for safely lowering a load in the event of hydraulic or electrical power loss.

Use extreme care when operating this equipment for the first time. Inexperienced operators should perform the various functions with no load to become familiar with the davit and its controls.

2.2 OPERATING CREW

The crane is designed to be operated by one crewmember

- the operator. However, additional crew members will be required to tend the hook, give signals to the operator, and handle rigging.

2.3 INSTRUMENTS AND CONTROLS

The operator must become thoroughly familiar with the location and function of all instruments and controls before operating the crane. Check all instruments immediately upon starting, and at frequent intervals during operation to ensure proper care through prompt detection of irregularities. If any instrument or control does not register or operate properly, secure power, and locate and correct the cause before resuming operation.

Figure 2-1 Cab Layout

Console (Figure 2-3)

Electrical Panel (Figure 2-2)

2 - 2

2.3.1 Electrical Panel

See Figure 2‑2.

1. Start Pushbutton (green). This button starts the hydraulic power unit (HPU).

2. Stop Pushbutton (red). This button stops the hydraulic power unit (HPU).

3. Flood Light Switch. A two position, ON-OFF, toggle switch that controls power to the floodlight.

4. Window Wiper Button. A two position, PUSH-ON/ PUSH-OFF button that controls the window wipers. Push the button once to activate the wipers. Push the button again to deactivate the wipers.

5. Beacon Switch. A two position, ON/OFF toggle switch that controls power to the beacon light.

6. Motor Running Indicator. When lit, indicates that HPU has power and is online to deliver pressure for functions.

7. Anti-2-Block/Overload Switch. When lit, indicates that crane is either in an anti-2-block or overload condition.

2.3.2 Control Console

See Figure 2‑3.

1. Boom Lever. Pull lever back to raise the boom; push lever forward to lower the boom.

Figure 2-2 Electrical Panel

3 5

2 - 3

2. Winch Lever. Pull lever back to raise the load; push lever forward to lower the load.

3. Swing Lever. Pull lever back to swing right; push lever forward to swing left.

4. System Pressure Gauge. Indicates current operating system pressure.

5. Boom Pressure Gauge. Indicates current pressure at the base of the boom cylinder.

2.3.3 Hydraulic Power Unit

See Figure 2-4. The Starter Box, mounted on the HPU, provides controls for service, and/or emergency purposes.

Starter Box controls include:

1. HPU Start Pushbutton (green). Pressing this button starts the HPU.

2. HPU Stop Pushbutton (red). Pressing this button stops the HPU.

Rotate disconnect counter-clockwise to "off" position before opening starter box.

3. Disconnect. This two-position actuator, shown in the “OFF” position, removes electrical power from the HPU.

Rotate disconnect counter-clockwise to “OFF” before opening the starter box.

4. Oil Level Sight Gauge. Indicates hydraulic fluid level.

The level should be between the "Low Oil" and "Full" mark.

5. Filter Indicator. Located on bottom of main filter housing. Replace filter element when red appears in window.

Figure 2-3 Control Console

4 5

2 - 4

Figure 2-4 Hydraulic Power Unit Controls

HPU

2 - 5

2.4 OPERATING THE CRANE

Inexperienced operators should perform the various functions with no load to become familiar with the crane and its controls. Always use a smooth motion when actuating controls to avoid sudden starts and stops.

CAUTION

Never continue to hold control levers in the actuated position after a component has reached its travel limit. This can cause hydraulic system overheating and equipment failure.

Use extreme caution when working at or near equipment operating limits.

2.4.1 Pre‑Operational Test

1. Check the reservoir fluid level on the hydraulic power unit (HPU) sight gauge, Figure 2-4.

2. Operate Crane Control Levers (Figure 2-3), and ensure that they return to neutral position when released.

3. Press the Start Pushbutton (Figure 2-2) and ensure the HPU starts. Allow the system to warm up, and ensure that the fault indicators are not activated.

2.4.2 Crane Operation

The following procedure is used for lowering a load into the sea during rough weather.

1. Perform the Pre-Operational Test specified in paragraph 2.4.1.

2. Use the control console and electrical panel controls to operate the crane. Take heed to observe all indicators from the visual advisory system when the crane reaches any operating limit.

2.4.2.1 Clearing Anti-Two-Block Condition

See Figure 2-5. "Winch Up" is inhibited when the Anti- Two-Block circuit is energized. To clear a Anti-Two-Block condition, “WINCH DN” or "BOOM UP" until the “A-2-B” indicator is no longer activated.

HPU

CAUTION

Ensure there is adequate overhead clearance before proceeding. Swing the crane as necessary to clear obstacles.

Figure 2-5 Clearing Anti-Two-Block

NO!

NO!

YES

LOWER THE LOAD

2.4.2.2 Clearing Overload Condition

See Figure 2-6. All crane functions are inhibited when an overload occurs. Perform the following steps to clear an overload:

Pressing ANY bypass switch places you in control of safety for that function.

Heed all other displays and alarms.

1. Press the OVERLOAD BYPASS switch.

2. “WINCH DN” or “BOOM UP” until the load is fully lowered. The aural alarm and “OVERLOAD” indicator will reset when the load sensed at the tip of the boom is less than the rated load.

Figure 2-6 Clearing Overload

NO!

YES

NO!

NO!

YES

YES

1. LOWER THE LOAD

2. RAISE THE MAIN BOOM

3. RETRACT THE EXTENSION BOOM

2 - 6

2.5 Emergency Operation

See Figure 2.7. In the event of electrical or hydraulic power loss, the crane is equipped with a self-contained emergency lowering system. The emergency lowering manifold is located by the left-hand side of the cab and includes the emergency hand pump, and a needle valve to allow emergency operation.

2.5.1 Winch Emergency Lowering

See Figure 2.7.

1. Close the needle valve (6) completely and then re-open 1/4 turn to allow pressure to slowly drain off.

2. Insert handle into hand pump and begin pumping to regenerate pressure. While observing the pressure gauge, use the hand pump to build pressure to winch brake. The winch brake will release at approximately 300–600 psi.

Note: Slowly open the needle valve to control the rate of decent for the winch.

3. Re-fill the emergency hand pump reservior as required.

Figure 2-7 Emergency Operation Components

2.6 Load Moment Indicator

Note: See Allied Systems Company forms 80- 606 and 80-607 in appendix A and figure 2-9 for information regarding calibration and operation of the Wylie 1250 series LMI.

See Figure 2-7. The Load Moment Indicator (LMI) is mounted in the upper left corner of the cab. Load Moment Indicator controls and indicators include:

1. Digital Display. A liquid crystal display (LCD) provides a constant readout of various crane parameters such as the hook load, maximum load for the present configuration, load radius, and parts of line.

2. Warning Indicators . The Warning Indicator alerts the operator to crane conditions and activates system lockout as conditions dictate. Conditions indicated are load at 85% of capacity or greater, load at 100% of capacity or greater, crane is approaching 2-blocking, the existence of any-out-of limit condition; such as low/high angle, maximum-length limit, maximum- radius limit, or maximum-height limit as set by the operator. The boom cannot be lowered or extended, nor

2 - 7 can the winch be raised until the overload condition has been relieved or override is selected. The last three indicators on the right do not apply to this installation.

3. Bar Graph Indicator. The bar graph indicator is located above the digital display. This allows the operator to see the load as a percentage of the maximum allowable load.

4. Keyboard. The keyboard provides the operator with the means for selecting the desired display and inputting the required data.

a. Key 1 (DISPLAY/UP ). Selects additional display screens like length, height, error reports, diagnostics, etc.

Also allows the operator to scroll up through menu options.

If not pressed within 10 seconds, the display returns to the main menu.

b. Key 2 (HOIST/SET). Pressing this button toggles to the next hoist (main load winch/fast winch) and selects the configuration last associated with the selected hoist. This key is also used to set values for other menu selections.

c. Key 3 (LIMITS/DWN ). Selects the limit variables for display and setting. (Setting is done in conjunction with keys 2 and 4.)

d. Key 4 (PARTS/SET). Pressing this button toggles to the next number of parts of lines (reeving) for the selected hoist.

e. Key 5 (BOOM/JIB). Pressing this button for this crane has no practical function since the Allied TB100-110 has only one boom and no jib.

f. Key 6 (CONFIG/DEDUCT). This button is not used on this crane.

WARNING

When bypass is selected, you control all crane functions. Heed all other displays and alarms.

g. Key 7 (BYPASS/ESC). Pressing this button momentarily bypasses lockout. Pressing this button can also return the display to the primary screen.

h. Key 8 (RIG/ENTER). There is no outrigger to set on this crane. Pressing the ENTER button confirms the entry of data and returns the display to main menu.

100%

GREEN YELLOW RED

85% 100% TWO

BLOCK

OUT OF

LIMITS

ROPE

LIMIT

JIB

ON

REAR/END OUTRIGGER

H

DISPLAY

UP

1 2

HOIST

LIMITS

DWN

SET

<SET

PARTS

BOOM

JIB DEDUCT

CONFIG

BYPASS

ESC ENTER

RIG

8W1250 LOAD MOMENT INDICATOR

SYSTEM

Figure 2-8 Load Moment Indicator

2 - 8 Figure 2-9 DT50-57 S/N 2003 Wylie LMI Electrical Installation Diagram

3 - 1

3.1 INTRODUCTION

See Figure 3-1. The DT50-55 crane can hoist both personnel and equipment using several systems working together: operator controlled Electrical and Hydraulic Systems—Swing, Boom, and Winch; and the Hydraulic Power Unit. Hoist speed is variable from 0 to 67 feet per minute (fpm) and swing rate is variable from 0-1.0 rpm.

The crane may be operated with the boom 0-80 degrees.

The boom, turret, and pedestal are structural members

CHAPTER 3

FUNCTIONAL DESCRIPTION

which support the load. The winch is mounted on the boom. The outer race of a shear-ball swing bearing is bolted to the underside of the turret. The inner race is bolted to the pedistal, which is welded to the deck. With the use of hydraulic and electrical swivels, the crane can rotate 360 degrees continuously. Crane rotation is achieved by two swing drives that engage a ring gear on the inner race of the swing bearing.

Figure 3-1 Functional Diagram

3 - 2

PRESSURE

HIGH

MEDIUM

LOW

PUMP

PLANETARY REDUCTION

GEARS

SPRING-APPLIED/

HYDRAULICALLY-RELEASED BRAKE

SPOOL

TO TANK

FRAME

DRUM SHELL

MOTOR

CONTROL VALVE

3.2 THEORY OF OPERATION

3.2.1 Swing Drive

See Figure 3‑2. Two swing drives are mounted on an eccentric flange adapter bolted to the turret, which is, in turn, bolted to the outer race of the swing bearing.

When the SWING control lever is actuated, a dual counterbalance valve releases the spring- applied/ hydraulically released brakes before engaging the drive motors. When the SWING control lever is released, the counterbalance valve and swing brakes prevent uncommanded rotation. Each swing drive pinion engages external gear teeth on the inner race of the swing bearing which is bolted to the pedestal, permitting the crane to swivel.

Figure 3-2. Swing Drive

3.2.2 Boom

See Figure 3-1. The boom is attached to the top of the turret at the trunnion mounts. The boom is positioned by a double-acting, hydraulic actuator. When the BOOM control lever is pulled or pushed, the hydraulic cylinder mounted between the turret and main boom raises or lowers the boom. Load-holding valves hydraulically lock the cylinder in the event that a hydraulic hose is damaged.

3.2.3 Load Winch

See Figure 3‑3. When the LOAD WINCH lever is actuated, the integral brake valve passes fluid to the brake to release the drum shaft before turning the motor. The motor drives the sun gear of the first stage reduction gears, and the planet gears drive the planet carrier. The first stage planet carrier drives the output sun gear, and the output planet gears drive the drum.

See Figure 3-4. When hoisting a load, sprag cams in the dynamic brake lay over to allow the inner race to turn independently of the outer race. Since the static brake remains fully engaged when raising a load, there is no braking action opposing the winch motor.

See Figure 3-5. When hydraulic pressure is removed, the load attempts to turn the primary sun gear in the opposite direction. This reverse input causes the sprag cams to instantly roll upward and lock the shaft to the fully engaged static brake.

F 3-

F 3-

F

3-

SPRAG CAMS

STATIC FRICTION BRAKE APPLIED

PERMITS FREE SHAFT ROTATION

WHILE HOISTING

LEGEND

1. HYDRAULIC MOTOR

2. BRAKE

3. GEAR REDUCER

4. PINION

Figure 3-3. Winch

Figure 3-4. Dynamic Brake, Hoisting

STATIC FRICTION BRAKE APPLIED

SPRAG CAMS

LOAD ATTEMPTS TO ROTATE SHAFT

IN OPPOSITE DIRECTION.

DYNAMIC BRAKE LOCKS SUN GEAR SHAFT

TO STATIC BRAKE.

Pilot pressure is required to open the brake valve and release the dynamic brake for lowering. After the brake valve opens, pilot pressure is flow-dependent and modulates the brake valve opening to control lowering speed. When the control valve is shifted to neutral, pressure will drop, and the brake valve will close.

3.2.5 Hydraulic Power Unit

See Figure 3-6. The hydraulic power unit (HPU) pump gets oil from the 100-gallon hydraulic oil tank via a suction strainer and discharges a maximum of 34 gallons per minute of hydraulic oil depending on system demand as determined by load sense. The pump delivers its output to the control valve, which in turn supplies oil to the system selected by the operator.

Fluid temperature is regulated by a thermostatically controlled, immersed tank heater and an air-to-oil cooler.

No audible or visual alarm signals are sent to the cab except for the system and boom pressures displayed on the cab control panel.

The 100-gallon hydraulic oil tank is fitted with a thermostatically controlled heater factory set to energize if ambient temperature falls below 70 °F. The heater can be energized or deenergized by the tank heater switch on the start box.

3.2.5.1. Starter

See Figure 5-1 The HPU starter is designed to reduce surge current demand on the supply generator when the HPU motor is started.

On a normal soft start, electric power is applied to the starter through a circuit breaker disconnect switch to one side of a silicon-controlled rectifier (SCR) on each line.

When the start button is pressed, the starter’s control circuit is energized and begins to overcome the SCR initial high resistance. Voltage sensed by the motor starts out low and is ramped slowly up to the 440-volt line input so the supply generator gradually picks up the load.

When the motor is receiving full voltage, a contactor closes to divert current from the SCR to prevent overheating. The solenoid valve closes and the pump builds pressure to make the hydraulic system operational.

Normal starting is initiated by pressing the START button on the cab control panel. The system can also be started by pressing the START pushbutton on the Starter box.

3.2.5.1.1 Motor Overload Protection

The motor has overload protection provided at the Starter box by the circuit breakers located between the motor and the DISCONNECT.

each piston moves outward, drawing hydraulic fluid through the port into the piston bore until its maximum

Figure 3-5. Dynamic Brake, Lowering

F 3-

Figure 3-6. Hydraulic Power Unit 3 - 3 stroke is reached. Then, the piston bore passes from the lower crescent port to the upper crescent port While rotating across the upper crescent port, each piston is forced into the cylinder, pushing fluid through the outlet port until its minimum stroke is reached. Next, the piston bore passes from the upper to the lower crescent port and the operating cycle is repeated.

LEGEND

1. CONTROL ACTUATOR

2. CYLINDER BEARING

3. SWASH BLOCK

4. SHAFT

5. SHAFT BEARING

6. PISTON & SHOE

7. CYLINDER BARREL

8. VALVE PLATE

9. VALVE PORTS

10. SHAFT SEAL

11. HOUSING

F 3-

Figure 3-7 Axial-Piston Pump

F 3-

F 3-

MAXIMUM

PARTIAL

Figure 3-8. Swashblock Positioned for Full Delivery Figure 3-10. Swashblock Positioned for No Delivery

Figure 3-9. Swashblock Positioned for Partial Delivery

MINIMUM

3 - 4

Figure 3‑9 illustrates how the angle of swashblock displacement determines the length of the piston stroke, and ultimately the delivery from the pump. In this example, a low angular displacement yields minimal delivery from the pump.

Figure 3‑10 shows the pump swashblock in neutral position (centered). When the swashblock face is parallel to the cylinder face, there is no inward or outward motion of the pistons as they pass over the swashblock face. Therefore, no fluid is displaced and delivery from the pump is zero.

3 - 5

BARREL

AND SLEEVE

CONTROL

PISTON

ORIFICE

PRESSURE

ADJUSTMENT

COMPENSATOR

SPOOL

MAXIMUM

VOLUME STOP

MINIMUM

VOLUME STOP

SWASH

BLOCK

PISTON

PLUG

TANK

SYSTEM PRESSURE

FROM

TANK

TO

SYSTEM

3.2.5.1.2 Control Circuit

See Figure 5-1. The starter supplies its own control voltage by a control circuit transformer off of 440-volt leads.

Remote control of the HPU is accomplished from the cab.

The HPU can be stopped directly at the Starter box or remotely by pressing the STOP button in the cab.

WARNING

INDICATORS MUST BE HEEDED— LOW/HIGH

OIL, LOW PRESSURE, HIGH TEMP, OR FILTER

BYPASS WARNINGS WILL NOT SHUT DOWN

THE HPU.

3.2.5.2 Axial-Piston Pump

See Figure 3‑7. The axial-piston, variable-displacement hydraulic pump is controlled by a load sensing compensator that controls the pump’s output pressure and flow as required.

As drive shaft (4) turns, piston & shoe assemblies (6) retained against the swashblock (3) are drawn in and out of rotating cylinder barrel (7). By varying the angular difference between cylinder barrel and control actuator (1), hydraulic oil flow changes.

Figure 3-11. Load Sensing Pressure Compensator

F 3-

See Figure 3‑8. When the load sense pressure compensator positions the swashblock for full delivery from the output port, the swashblock face is at maximum displacement angle to the cylinder face. As the cylinder rotates, pistons move in and out of their bores while the shoes ride against the angled swashblock.

When the cylinder rotates, individual piston bores are alternately connected to the inlet and outlet crescent shaped ports in the valve plate. While connected to the inlet port,

3.2.5.3 Load Sensing Pressure Compensator

See Figure 3‑11. Pump output, flow, and pressure are regulated by the load sensing pressure compensators. The load sensing compensator modulates pump output in response to system demand.

As system pressure falls below the pressure set by the pressure adjustment module, the compensator spool’s spring overcomes the oil pressure and shifts the spool to allow the pressure on the control piston in the volume control module to leak off to the HPU tank. The control piston then positions the swashblock for full delivery.

3 - 6

When system pressure builds, hydraulic oil pressure overcomes pressure adjustment module spring pressure and the compensator spool is positioned so that oil is delivered to the bottom of the volume control module’s control piston. As the pressure starts to overcome the spring pressure in the volume control module, the control piston is displaced in the upward direction. This repositions the swashblock, lessening the output of the pump. This will continue until there is no output from the pump.

3.2.6 Control Valve

See Figure 3-12. The control valve consists of three sections that provide hydraulic oil to the load winch, lift cylinder, and swing drives.

Together with the winch, swing drives, lift cylinders, and associated plumbing, the control valve completes the circuit between the HPU and the crane.

All three working sections use anti-cavitation check valves to prevent vacuum buildup in a line from causing pitting in the valve body.

3.2.6.1 Swing System

The Swing System, consisting of the swing section of the control valve, swing dual counterbalance valve, two swing drives, and associated plumbing, controls crane rotation.

When the swing lever is not actuated, the swing dual counterbalance valve traps fluid inside the swing hydraulic motors, preventing them from rotating. The dual counterbalance valve begins to open at 500 psi and hydraulic pressure is directed first through an internal shuttle valve to release the swing brakes before driving the hydraulic motors.

3.2.6.2 Winch System

The Winch System, consisting of the winch section of control valve, winch, and associated plumbing, controls the winches by directing fluid pressure to the motor, which drives the cable drum to hoist a load.

A brake shuttle allows the load to be lowered in the event of a hydraulic power loss.

3.2.6.3 Boom System

The Boom System controls boom elevation and extension boom extension.

3.2.6.4 Hydraulic Overload Safety System

Load-holding valves prevent the cylinders from retracting suddenly in the event of a ruptured hydraulic oil line.

These valves allow free flow to the base-end of the cylinder.

A check valve built into the cartridge prevents reverse flow to the control valve. The load-holding valves also prevent cylinder retraction until sufficient back pressure, approximately 850 psi, builds in the stem-end of the cylinder. When the cartridge opens, fluid exits the cylinder and returns to tank. With this design, the boom cannot free-fall because it must be powered down.

To protect the crane from hydraulic shock and pressure spikes, the load holding valves relieve pressure to the tank at 3,100 psi.

The Hydraulic Overload Safety System prevents boom lowering or winching up (with any given load) at a radius that creates an overload condition. When this happens, the hydraulic system automatically locks the boom in place and the winch in a brake on condition. The operator will only be able to raise or retract the boom to reduce the radius, or lower the load with the winch.

Figure 3-12. Control Valve Schematic

3 - 6

PROXIMITY

SWITCH

SPRING

SENSOR ARM

WEIGHT

& CABLE

1/16"

Figure 3-13. Anti-2-Block Control

3.2.6.5 Emergency Lowering System

A hand pump is provided to allow the operator to lower the load manually by applying pressure to release the winch brake.

3.2.7 Electrical System

See Figure 5-1.

3.2.7.1 Anti-2-Block Control

See Figure 3-13. The Anti‑2‑Block Control, consisting of a proximity switch, sensor arm, spring, and weight and cable, is designed to prevent the operator from hoisting the hook into the sheave. During normal operation, the weight will hang freely, maintaining tension on the cable which in turn pulls the sensor arm away from the proximity switch.

When the hook nears the top of its travel, it lifts the weight, relieving tension on the cable and a spring draws the sensor arm toward the proximity switch. When the switch is energized, boom extension and winch up controls are locked out.

3 - 7

3 - 8

4 - 1

CHAPTER 4

SCHEDULED MAINTENANCE

➁. GEAR LUBRICANT. Formulated for lubricating exposed gears.

➂. Winch Cable Lubricant. Formulated for lubricating cables.

➃. Swing Gear Reducer Oil. Use HD 80W-90 multipurpose gear oil.

➄. WINCH GEAR REDUCER OIL. Use HD 80W-90 multipurpose gear oil.

➅. HYDRAULIC SYSTEM FLUID. Low Temperature Hydraulic Fluid. Use only premium grade, anti-wear hydraulic fluid. The manufacturer recommends Mobil DTE 13M.

NOTE: Failure to use the recommended fluid during the warranty period may void warranties (expressed or implied) on related hydraulic components if an inspection indicates a lubrication-related cause.

Fluid samples will be required with a submission of all hydraulic components for warranty con sideration.

4.3.3 Crane Service Instructions

The Maintenance and Lubrication Chart (Table 4‑1) shows maintenance and lubrication points.

Numbers in the REF column correspond to Figure 4-1 and/or the following paragraph numbers.

1. HOOK SWIVEL & TRUNNION.

Inspect the hook for excessive wear, distortion, or cracks.

Ensure that the latching device is working properly.

Replace the hook if required.

2. CABLE SHEAVE & PINS.

No lubrication is necessary. Check sheave pin, bushing and sheave groove for excessive wear or damage. Replace any parts as required.

4.1 INTRODUCTION

Periodic maintenance and lubrication is necessary to ensure long life and proper function of the crane’s components. To obtain the best performance and prevent unnecessary wear, it is essential that the maintenance and lubrication schedules in this chapter be followed. If the crane is operated extensively, or in severe conditions, service intervals should be shortened.

4.2 PREVENTIVE MAINTENANCE

A sensible, conscientiously applied preventive maintenance program can greatly reduce the chance of equipment failure and increase the service life of the crane. A preventive maintenance program should be based on the maintenance and lubrication charts, plus the amount of anticipated use of the crane.

4.3 SCHEDULED MAINTENANCE

4.3.1 Walk-Around Inspection

Operators must perform a walk-around inspection before each operating session, looking for loose fasteners, leaking connections, worn or damaged hoses, or any other defects or dangerous conditions. Promptly report any defects to the proper authority.

4.3.2 Lubricant Specifications

All lubricants and oils used on the equipment shall conform to the following specifications. The numbers in the Frequency of Maintenance fields of the Maintenance and Lubrication Chart (Table 4‑1) correspond to the lubricant specification item numbers below:

➀. Grease. Use only EP1 or EP2, multipurpose grease containing molybdenum disulfide (MoS2) and a suitable corrosion inhibitor. Use for lubricating roller, ball or bushing type bearings.

For ambient temperatures below 10° F (-12° C) use EP1.

For ambient temperatures above 10° F (-12° C) use EP2.

4 - 2

Figure 4-1. Maintenance and Lubrication Diagram

4 - 3

MAINTENANCE POINT DESCRIPTION FREQUENCY OF MAINTENANCE

REF in paragraph 4.3.2. An “X” in this position indicates DAILY WEEKLY MONTHLY AS

1 HOOK SWIVEL & TRUNNION

2 CABLE SHEAVE & PINS

3 WINCH CABLE ➂

4 WINCHES ➄

5 BOOM PIVOT PINS

6 LIFT CYLINDER

7 SWING GEAR REDUCER ➃

8 CRANE MOUNTING BOLTS

9 SWING BEARING ➀

10 PINIONS AND RING GEAR ➁

11 FASTENERS

12 HYDRAULIC LINES AND FITTINGS

13 CRANE INSTALLATION

14 HYDRAULIC TANK ➅

15 HYDRAULIC TANK BREATHER

16 RETURN FILTER

17 STARTER

4 - 4

3. Winch Cable

WARNING

Wear gloves when handling wire rope.

Lubricate to prevent rust and internal friction. Apply lubricant to the cable while it passes through the sheave, working it into the valleys between the strands, coating the outer wires and lubricating the wire rope at the base of the end fittings. Remove excess grease from the cable.

Periodically inspect the entire length of the winch cable.

Look for fraying, severe kinks, broken strands, or rust. If any damage is found, the entire cable must be replaced.

Table 4‑2 lists allowable wire rope tolerances. If the winch cable fails to meet these standards, it must be replaced.

NOTE: The inspection, care, and maintenance of the winch cable should comply with current safety rules.

Table 4-2 Wire Rope Tolerances

4. WINCHES.

Check the winch assemblies for leaks. To check the fluid level, clean the area around the plug on the top of the gear reducer spacer and the plug on the cable drum barrel, and then remove the plugs. The fluid levels should be visible through the holes. Add approved fluid as required.

NOTE: Disassemble the winch, inspect all wear items and replace fluid annually or every 2,000 operating hours, whichever occurs first. See Chapter 6 for winch disassembly and inspection procedures.

5. BOOM PIVOT PINS.

Check for excessive wear and movement. Ensure that trunnion capscrews are tight.

6. LIFT CYLINDER.

Hydraulic cylinders should be checked during operation for leakage around the cylinder stem. If leakage is present, the cylinder should be serviced. Leaking piston seals will not cause visible leakage, but will result in the boom dropping under a load.

7. SWING GEAR REDUCER.

To check the oil level, clean the area around the plug on the top of the gear box, and then remove the plug. The oil level should be visible through the hole. Add approved gear oil as required. Check the swing drive for leaks.

Drain and fill with fresh oil annually or every 2,000 hours.

8. CRANE MOUNTING BOLTS.

Check the crane mounting bolts for tightness after the first 3 to 4 hours of operation. Thereafter, check the tightness every 200 hours of operation. Make sure that all of the hardware is in place and of the correct grade. Tighten the crane mounting capscrews to 450 ft-lb.

9. SWING BEARING.

Lubricate the swing bearing through the lube fitting located on the bearing. Rotate the crane in 30-degree increments through its entire swing arc between applications. Rotate the crane after lubricating to distribute the lubricant.

WARNING

SHUT OFF THE ELECTRICAL SUPPLY TO

THE HYDRAULIC POWER UNIT BEFORE

PERFORMING MAINTENANCE OR SERVICE ON

THE PINIONS AND RING GEAR. FAILURE TO

DO SO COULD CAUSE SERIOUS INJURY OR

DEATH.

11. PINIONS AND RING GEAR.

The swing gear is located on the underside of the turret.

Distribute lubricant around the outside face of the gear.

Visually inspect the gear and pinions for excessive wear or damage; ensure that the pinion retaining caps and capscrews are secure.

12. FASTENERS.

Unless otherwise specified, check all fasteners for tightness every 6 months.

13. HYDRAULIC LINES AND FITTINGS.

Inspect all hydraulic lines and fittings for damage or leakage and tighten or replace as required. Replace any hose, fitting, or O‑ring that is damaged or leaking during operation that cannot be corrected by proper tightening.

Never attempt to stop a leak by overtightening.

4 - 5

14. CRANE.

a. Give the crane a fresh water washdown weekly. On a monthly basis, thoroughly clean crane with detergent and fresh water. Rinse with fresh water.

b. Inspect crane structure and associated components for cracks, corrosion and physical damage.

c. Prepare and paint chipped or damaged surfaces.

Apply a thin coat of silicone compound to bare metal surfaces.

d. Return the crane to…