Basic Hydraulics

Course Topics

Inspections

HOP Systems

Cylinders and Collector Blocks

Chain and Cable

Inspections

TEREX Utilities Service SchoolInspections and Preventative Maintenance

ANSI American National Standards Institute

Who’s responsibility?

OWNER AND USERPerformed by a qualified person(s)

QUALIFIED PERSON:A person who, by possession of an appropriate technical degree, certificate, professional standing, or skill, and who, by knowledge, training, and experience, has demonstrated the ability to deal with problems relating to the subject matter, the work, or the project.

Regular Inspection & Tests

• The inspection procedure for mobile units is divided into two classifications based upon the intervals at which inspections and tests shall be performed.

• Safe intervals shall be set by the USERbased on the recommendations that shall be supplied by the MANUFACTURER.

Inspections

• FREQUENT INSPECTIONDaily to monthly intervals

• PERIODIC INSPECTIONOne to twelve month intervals

Service Bulletin 5-504-97

• MAJOR OVERHAULS / MAJOR INSPECTIONS:In response to questions relative to our position on the required major overhaul / major

inspections please reference the following:

• Terex Telelect’s Position on Major Overhaul and Major Inspections:

A documented, scheduled preventative maintenance and inspection program that is both thorough and complete is acceptable in lieu of the mandatory; five year major overhaul or major inspection. Should the regular inspections reveal worn or damaged components, we would recommend the major overhaul or major inspection be performed.

It should be noted however that units which accomplish bucket leveling or boom lift via means of chains or cables are still subject to the recommended inspection or replacement of the bucket leveling or boom lift components as outlined in the unit manual.

Terex Telelect’s goal is to provide a safe and reliable piece of equipment. With proper operation and maintenance, Terex Telelect will provide a long and economical service life.

PREVENTATIVE MAINTENANCEA preventative maintenance program based on the manufacturer’s recommendations shall be established.Dated and detailed records shall be readily available. It is recommended that the replacement parts be obtained from the original equipment manufacturer.MAINTENANCE PROCEDUREBefore adjustments and repairs are started the following precautions shall be taken as applicable:� You must be authorized by the owner to operate unit.� Place machine where it will cause the least interference with other equipment or operations in the area.� All controls at the off position.� Starting means rendered inoperative.� Warning or “OUT OF ORDER” signs placed on the machine.� Power plant stopped or disconnected at power takeoff.� Boom lowered to the ground if possible or otherwise secured against dropping.� Retract all hydraulic cylinders used for boom lift and articulation.� Relieve hydraulic oil pressure from all hydraulic circuits before loosening or removing hydraulic components.After adjustments and repairs have been made the machine shall not be operated until all guards have been reinstalled, trapped air removed from hydraulic system, safety devices reactivated, and maintenance equipment removed.Warning or “OUT OF ORDER” signs shall be placed and removed by authorized personnel only.

Maintenance Guidelines

ADJUSTMENTS AND REPAIRSAny unsafe conditions disclosed by the inspection requirements of this section shall be corrected before operation of the machine is resumed. Adjustments and repairs shall be done only by qualified personnel.

Adjustments shall be maintained to assure correct functioning of components. The following are examples:• All functional operating mechanisms.• Safety devices.• Control systems.• Power plants.

Repairs or replacements shall be provided promptly as needed for safe operation. The following are examples:• All critical parts of functional operating mechanisms which are cracked, broken, corroded, bent or excessively worn.• All critical parts of the machine structure which are cracked, bent, broken or excessively corroded.• Hooks showing defects disclosed by “Frequent Inspection” requirements in the maintenance manual shall be discarded. Field repairs by welding or re–shaping shall not be permitted.

All replacement parts or repairs shall have at least the original safety factor.

Maintenance

LUBRICATIONAll moving parts of the machine, for which lubrication is specified, shall be regularly lubricated. Lubricating systems shall be checked for proper delivery of lubricant. Particular care should be taken to follow manufacturer’s recommendations as to points and frequency of lubrication, maintenance of lubricant levels and types of lubricant to be used.Machinery shall be stationary while lubricants are being applied and protection provided as called for in “Maintenance Procedure”.OPERATIONAL CHECKLISTSSee Frequent and Periodic Inspection Intervals before operation of the Digger derrick.GENERAL INFORMATION1. Keep inspection records up–to–date.2. Record and report all discrepancies to your supervisor.3. A dirty machine cannot be properly inspected. Keep your Digger Derrick clean!!4. Maintenance and frequency of maintenance has been established by TEREX TELELCT, however this is subject to change to a lesser frequency if working in dusty, dirty, or wet environment.

The following checklists must be used daily, 30 days (120 hours), 90 days (360 hours),180 days (720 hours), 12 months (1,050 hours). Failure to do so could endanger the life of the operator. Always remember, preventive maintenance can save much more than it costs.NOTE: The check points listed are the minimum recommended by Terex Telelect. They are subject to supplementation to conform with your own company regulations.

Maintenance

Frequent & Periodic inspection intervals

• Daily 5FC• Check controls at platform and lower controls for proper operation.• Inspect for safety belt and attachments.• Inspect visual and audible devices.• Check cleanliness and dryness of fiberglass components.• Check for missing and illegible operational or instructional markings.• Visually check oil level in hydraulic reservoir.• Inspect for leaks in hydraulic system.

• 30 DAYS 5FC• Visually check all cylinders for leaks.• Visually inspect leveling system• Visually inspect all fasteners for tightness• Visual inspection of all structural members for cracks and permanent deformation.• Check for rotational obstructions• Visual inspection of all electrical wires.• Operational test of all boom functions.• Daily Inspection.

Frequent & Periodic inspection intervals

• 90 DAYS 5FC• Replace return filter.• Check tension on leveling system.• Visually inspect all sprockets, pulleys and pins.• Check tightness of turntable bearing bolts, mast bearing, and bearing to tower for

proper torque.• Lubricate all points per lubrication chart recommendations.• Daily and 30 Day

• 180 DAYS 5FC• Apply lubricant to turntable gear box and winch speed reducer.• Daily, 30 Day, and 90 Day Inspection.

• 12 MONTHS 5FC• Inspect and lubricate PTO drive shaft to pump.• Take samples of hydraulic oil and test.• Check all hydraulic pressure adjustments for proper setting.• Replace hi-pressure filter.• Daily, 30 Day, 90 Day, and 180 Day Inspection

DATED: 05/17/2001 REVISED MODEL (S): All units SUBJECT: Maintenance and Inspection of Digger Derricks and Aerial Devices

• This bulletin is to serve as a reminder to all owners and users of Terex Telelect equipment of the importance of proper maintenance and inspections of this equipment.

• Each unit model has specific maintenance and inspection requirements, which if followed, will provide safe and reliable service for many years. Conversely, a piece of equipment, which is not properly inspected and maintained, may become a hazard to the operator as well as other workers near it.

• Such has been the case in a recent incident. The bearing in a boom lift cylinder seized up due to lack of lubrication. This caused the retainer pin failure resulting in the cylinder pin backing out and the boom falling. Fortunately this did not result in serious operator injury. This however, would have been prevented had proper maintenance and inspections been performed.

• It must be noted that both ANSI 92.2–1990, Section 8, (Aerial Devices) and ANSI 10.31–1995, Section 8, (Digger Derricks) require the user to perform maintenance and inspections. It is the position of Terex Telelect that the maintenance and inspection intervals indicated in unit maintenance manuals and on unit lubrication charts are critical and must not be exceeded without prior factory approval.

PRODUCT ADVISORY PA-1002-01

Lubrication

• All moving parts of the machine, for which lubrication is specified, shall be regularly lubricated.

• Lubricating systems shall be checked for proper delivery of lubricant.

• Particular care should be taken to follow manufacturer’s recommendations as to points and frequency of lubrication, maintenance of lubricant levels and types of lubricant to be used.

Lubrication Chart

• Refer to the Lubrication Chart located in your Maintenance Manual and on the placard on your unit.

22

21

17 3 4

19

1,4

21

10

25

18

13

5,6,8

24

7

11

16

1

1 17

26,23

1514

Storage procedure

• Wash and clean the unit to remove accumulated road grime. It can discolor the paint if left on for long periods of time.

• Clean and wax the fiberglass components. If storage is in the sun, cover the booms.

• Clean and coat the exposed cylinder rods with grease, preservative spray or heavy preservative oil.

• Clean and grease the exposed valve spools and linkage.• Lubricate the entire machine following the lube chart.• Check the oil for pH level and water content. Acidic oil or water

in the oil may settle out during storage and can rust the interior of the hydraulic system.

HOP Systems

HYDRAULICOVERLOADPROTECTION(H.O.P.)

•HERE'S HOW

HYDRAULICOVERLOADPROTECTION(H.O.P.)

IS USED . . .

BOOM LIFT CYLINDERCAPACITY IN THISPOSITION IS 6000 LB.

DERRICK RELIEFIS SET AT 2400 PSI SO . . .2400 PSI IN THE BASE OF THELIFT CYLINDERS WILL LIFT 6000 LBAT A 45 BOOM ANGLE.

2400 PSI IN THE BASE OF THELIFT CYLINDERS WILL LIFT 13,000 LBAT A 75 ANGLE.

REMEMBER . . .

The Lift Cylinders Have "Brains". They Only Lift The Amount The Boom Position And2400 PSI In The Base Of The CylindersWill Allow Them To Lift.

THE LOAD CHART AMOUNT

WINCH RELIEFIS SET AT 2300 PSI SO . . .2300 PSI IN THE WINCH MOTORWILL ALLOW THE WINCHTO LIFT 12,000 LB.

THE WINCH RATING

REMEMBER . . .The Winch Doesn't Know What TheBoom Angle Is. It Can And Will Lift 12,000 lbWhen The Boom Angle Or Extension IsNot In A Position To Support 12,000 lb.

OPERATOR USES WINCH TOLIFT THE LOAD

THIS CAUSES OVERLOAD ON LIFT CYLINDERS,

INCREASING THE HYDRAULIC PRESSURE IN

THEBASE OF THE LIFT

CYLINDERS.

REMEMBER . . .

THE H.O.P. READS THE EXCESSIVE HYDRAULIC PRESSURE AND STOPS THOSE FUNCTIONS WHICH CAUSE OVERLOAD:

1. WINCH UP.2. DIGGER DIG.3. STINGER OUT.4. HYDRAULIC 3RD OUT.

1. The Reverse Of Each Function Still Works!Winch Down.Digger Reverse.Stinger In.Hydraulic 3rd In.

They Do Not Cause Overload.

2. The Hydraulic Overload Protection Has No Effect On The Lift Cylinders Ability To Lift The Rated Load. If The Cylinders Won't Lift The Rated Load There Is Something Else Wrong, It's Not The H.O.P.

3. The H.O.P, Has No Effect On Winch Down, DiggerReverse, Stinger In And Hydraulic 3rd In.

4.Improper Adjustment Or Malfunction Of The H.O.P. Can Affect Operation Of Winch Up, Digger Dig, Stinger Out And Hydraulic 3rd Out.

5. If The Boom Is Fully Lowered To The End Of The Lift Cylinder Travel, There Will Be A Mechanical Connection Rather Than Hydraulic And The H.O.P. Will Not Function.

6. Boom Down H.O.P. Can Be Added To The Standard Four-Function H.O.P.

SETTING THE UNIT UPPROPERLY IS VERY

IMPORTANT!!!

The Boom Angle Indicator IsRelative To The True VerticalCenterline - Gravity Points

The Angle Indicator.

•THE LIFT CYLINDERS LIFTING ABILITY IS BASED ON THE BOOM ANGLE RELATIVE TO THE MAST AND TOWER TOP PLATE HORIZONTAL CENTERLINE.

When The Unit Is Set Up On An Incline The Boom Angle Indicator Places The Boom At An Angle Based On True Vertical, Not The Mast and Tower Top Plate Horizontal Centerline.

THE LIFT CYLINDERS WILL THEN LIFTMORE OR LESS THAN THELOAD CHART DEPENDING ON WHICH DIRECTION THE INCLINE IS.

MANY LIFTING PROBLEMS CAN BEATTRIBUTED TO IMPROPER SETUP.

•WITH THE TRUCK SET UP ON THIS 5 DEGREE SLOPE THE LIFT CYLINDERSWILL HAVE A 50 DEGREE BOOM ANGLELIFT CAPACITY,BUT THE ANGLE INDICATOR WILL SHOW THE BOOMBEING AT45 DEGREES.

WITH THE TRUCK SET UP ON THIS 5 DEGREE SLOPE

THE LIFT CYLINDERS

WILL HAVE A 40 DEGREE BOOM

ANGLELIFT CAPACITY,BUT THE ANGLE

INDICATOR WILL SHOW THE BOOM

BEING AT45 DEGREES.

Cylinders and Collector Blocks

HYDRAULIC CYLINDERS

AND

COLLECTOR BLOCKS

HYDRAULIC CYLINDER OPERATION

The function of a hydraulic cylinder is the opposite of a hydraulic pump. It converts the hydraulic force intomechanical force. A cylinder performs its work in a straight line, is attached directly to the load, and is actuatedby the fluid in the hydraulic system.

Standard cylinders (See illustration below) consist of an outer case, a piston rod with an eye at one end and apiston head on the other, and seals and packings to maintain proper pressure contact and prevent oil leakage.

Among the seals used in Terex–Telelect cylinders, the most common are: U–cup, Teflon piston rings, “O”rings, and wear rings.The pistons and head glands are made of steel, cast iron or aluminum.

The rod wiper is used only to keep dirt out of the primary rod seal.The seal inside the cylinder head gland forms the pressure seal against the sliding piston rod to keep oil in.

CYLINDER SEALS

In most cases, seal rings are used in conjunction with nylon or phenolic wear rings.Typical application of seal ring with wear rings is shown.

USE OF OIL SEALSThroughout any hydraulic system numerous oil seals are used to prevent seepage in control valves, hydrauliccylinders and fittings.The most commonly used are ”O” rings or ”quad” rings. These two types and how they react to variouspressures are illustrated below. Backup washers are often used to prevent damage to seals as shown.

CYLINDER KIT SHEET (PARTS)

HYDRAULIC CYLINDER REPAIR

All hydraulic cylinders should be tested for internal leakage annually. Refer to “Hydraulic Cylinders Leakage Test” in this manual for testing procedure. Check cylinders for external leakage daily. If leakage is detected, check cylinder head. If head is tight and cylinder still leaks, the external tube fittings and seals must be replaced. Shut down the hydraulic system before removing any cylinder. Remove lines to cylinder and plug or cap them to prevent loss of fluid. Also plug cylinder ports to prevent loss of fluid. Tag or mark lines to prevent reversing connection when reassembling. See the appropriate section in this manual for the removal of cylinders. Outrigger cylinders should be repaired when they tend to drift down during road travel or up when extended in working position and the lock valves are not at fault. This downward drift indicates leaking cylinder seals. Immediate attention should be given to any outrigger cylinder that drifts. Damage could result if an outrigger should drift down during road travel.

Care should be exercised when removing cylinders, as they are heavy. Cylindersshould be removed by means of a hoist, if available.

1. Position the cylinder on a rail (if available) or a work bench and place the open port over a container inorder to catch the hydraulic fluid. Extend the piston to the end of its stroke to purge the hydraulic fluid intothe container. This can be done by using the rail (if available) or by manually pulling out the piston rod.Next, push the piston rod approximately one–half way back in.

HYDRAULIC CYLINDER REPAIR

Do not use air pressure to disassemble hydraulic cylinders. Air is very compressiveand serious injury could result.

When cylinder is disassembled, check cylinder rod bearings/bushings for possiblewear and replace if necessary.

2. Remove gland nut or thread ring and plate on end of cylinder. Remove entire internal assembly from cylinder case by pulling on the piston rod. Pull out carefully to avoid scratching the inner finish. Inspect the inside of the case for gouges that would make an overhaul useless.

3. Remove all components from rod. Examine all components for wear, rust or other signs of deterioration. Clean all components of rust, especially inside the cylinder case. Make sure that all components are free of dirt or other contamination. After cleaning, coat all components with light grease before installing new seals and other parts.

COLLECTOR BLOCK (SWIVEL JOINT)

The hydraulic swivel is a continuous 360° rotating fluid transfer manifold. This device makes it possible tooperate any or all of the equipment on the derrick, even while rotating – without twisting or abrading the hoses.The inner core is fastened to the mast with hydraulic lines connecting to the core. The surrounding portedhousing “floats”. “O” rings in the top and bottom channels prevent external leakage. Glass reinforced teflonrings with a backup “O” ring are used as seals between channels.Optional electric slip rings, air, vacuum and hydraulic “piggy back” hydraulic swivels may be added dependingon options and derrick configurations.All input and output ports are numbered on the inner block and the outerhousing for quick, easy channelidentification.

COLLECTOR BLOCK (SWIVEL JOINT)

PIGGY BACKCOLLECTOR

ELLECTRIC COLLECTOR RINGS

COLLECTOR BLOCKS (SWIVEL JOINT)

Chain and Cable

TEREX-TELELECT SERVICE SCHOOL

CHAIN AND CABLE INSPECTION / MAINTENANCE

CHAIN MAINTENANCE

GENERALBoom Tip ChainChain life is generally considered to have expired when the chain does not engage properly with the sprocket due to damage of its parts or elongation. The chain is replaced when this occurs. The service life of the chain can be influenced by a variety of factors. The following information discusses the care and maintenance required to help insure the chain’s integrity. Because the chain is a critical linkage it is essential that it receive proper care and maintenance. The key to proper care and maintenance is a systematic inspection, proper cleaning, and proper lubrication.To help prevent premature wear or damage, the following points should be checked. Observe the chain and sprockets for these items.

CHAIN MAINTENANCE

ITEMS TO OBSERVE1. Abnormal noise.2. Vibration of the chain.3. Chain rising on the sprocket.4. Chain winding around the sprocket.5. Stiff bending of chain, or kinks.6. Amount and state of lubrication.7. The appearance of the chain. Check for dirt, corrosion, damage on the outside surface of roller, contact marks, etc. Also check the inside and edge surfaces of the link plate and edge surface of the pin.8. Damage on the sprocket tooth surface and side surface of tooth and engaging area.9. Bending of chain and rotation of roller.

CHAIN MAINTENANCE

MAINTENANCEInspectionChains must be inspected per guidelines outlined in the inspection section of this manual.. Signs of chain deterioration to be looked for are as follows:1. A crack or complete break of a link plate, particularly an outer plate on either side of the chain. Replace chain immediately.Cracked Plates (Fatigue)

Example of expanding crack

CHAIN MAINTENANCE

2. Distortion or spreading of an outside link plate, evidenced by increased clearance between overlapping link plates and roller. This indicates a hidden break in a pin. (See illustration below) Replace chain immediately.

Link Plate Distortion

3. Looseness between the riveted ends of a chain pin and the outer link plates. If a pin has broken, the normally rigid riveted joint may loosen, leaving visible clearance around the exposed ends on the pin. (See illustration below) Replace chain immediately.

Clearance at Riveted Chain Pin

CHAIN MAINTENANCE

4. The pin head rivets should be examined to determine if the V–flats are still in correct alignment. Chain with rotated or displaced heads or abnormal pin protrusion indicates deformed pin or bushing fit. (See illustration below) Replace chain immediately.

Turned Pin5. Seizing and galling of rollers. All rollers must rotate freely by hand. If chain joints or rollers are seized, butnot yet damaged, lubricate per instruction in “Lubrication” Section.

CHAIN MAINTENANCE

6. Worn or mis-aligned idler sprocket(s) or sector sprocket(s). Worn idler sprocket bearing, sprocket hingepin or abnormal wear on sprocket teeth can cause chain overload and accelerate the wear rate. Replace the sprocket when teeth show excessive wear or are hook–shaped. Replace sprocket bearing or hinge pin if worn. Hooked Teeth

CHAIN MAINTENANCE

7. Inspect for accumulation of foreign matter such as dirt, grit, dust, etc., which can close off the clearance atthe suggested points of lubrication. If accumulation is evident, the chains should be cleaned by flushing and brushing with a suitable solvent such as diesel fuel or kerosene to remove all foreign material and then re–lubricated thoroughly.If the accumulation is severe, the chain should be removed and purged of foreign matter by soaking and flushing in suitable solvent, followed by immersion in proper lubricant before reinstallation.

8. DO NOT exceed the service life period of the chain. The maximum service life of a compensating chain should never exceed five years. The maximum service life of a leveling chain is determined by measuring chain elongation. Leveling chains which exceed the maximum elongation must be replaced. (Ref: Maintenance Manual)

CHAIN MAINTENANCE

One of the most important but often overlooked factors causing premature wear or breakage is inadequate lubrication. In addition to reducing internal friction, maintaining a film of lubricant on all chain surfaces will inhibit rusting and corrosion. Under normal operating conditions, especially in dusty environments, lubricated chains will accumulate a paste–like build–up of grime. This build–up should never be permitted to accumulate sufficiently to seal off the clearances, thereby restricting the lubricant to the bearing areas. At periodic intervals, this build–up must be removed by cleaning, and the chain immediately re–lubricated. DO NOT steam clean or use degreasers; use a brush and a safe petroleum solvent such as diesel fuel or kerosene.

CHAIN MAINTENANCE

Lack of lubrication will result in galling and corrosion of the chain pins, and can cause breakage of the pins, with resulting

failure of the leveling or boom lift system, and may result in serious personal injury or death.

The internal bearings between the pins and rollers in the chain should be lubricated on the unit per the lubrication chart and/or Quick Reference Guide. Lubricant should be room temperature to provide better penetration to the chain joints. Apply ample lubricant at each pin, between inner and outer side plates, and between inner side plates and roller. DO NOT, under any circumstance, apply grease lubricant to the chain, as grease will not penetrate to the pin bearings. Lack of lubrication in the pin bearings is usually indicated by squealing or groaning sound when the boom is operated.

CHAIN MAINTENANCE

Proper Penetration of LubricantIf lubrication has been neglected to the point of causing any chain joint to seize, the entire chain must be removed from the unit, thoroughly cleaned with a safe solvent, such as diesel fuel or kerosene, then soaked overnight in a container of recommended lubricant, providing that the chain has been thoroughly inspected for the absence of any kind of damage. Replace the chain if any defects are found.

30W SAE NON-DETERGENT OIL RECOMMENDED FOR ALL CHAINS.

CHAIN MAINTENANCE

Turned Pins

CHAIN MAINTENANCE

REPLACEMENT OF CHAINS1. When replacing a chain, replace the entire chain. DO NOT replace links or build lengths of chain from individual components.2. DO NOT paint the chain. Although paint may help inhibit external corrosion, it will seal off critical clearances and restrict oil from reaching the internal pin surfaces where it is needed for adequate joint lubrication. Always protect chain from paint when painting unit, especially during new unit installation or unit transfer.3. Protection from corrosion is important in storage as well as in service. A factory lubricant has been applied to new chains. After installation, the recommended lubricant must be used.4. Ensure that other component parts, sprocket, bearing and idler assembly are installed properly per Maintenance and Service Manuals.

CABLE MAINTENANCE

All cables should be visually inspected and lubricated after every 30 days of 120 hours of operation, which ever occurs first. ANSI requires that a record of these inspections should be kept, indicating when inspected, by whom, and the results of the inspection. A 30 day cable inspection should be conducted:1. To prevent an accident in the event of a cable failure.2. To improve cable performance, which affects equipment performance.3. To determine necessary adjustments to be made.4. To establish the need for immediate replacement if a cable is found to be defective.

CABLE MAINTENANCE

HI RANGERS have partially exposed and partially concealed cable lengths. All access and inspection covers should be removed in order to observe the condition of as much cable run as possible. Particular attention should be given to the two 1 / 4” and one 3 / 8 ” cables passing around the elbow sheave and the three 1/4” cables at the platform sheave, if applicable. Replace cables if any of the following are discovered as a result of any inspection:•In any cable, two or more broken wires.•The presence of any physical damage to cable or fittings.•The presence of an electrical burn.•Rust that is of sufficient depth the wire cannot be made rust free by vigorous rubbing with a cloth.

CABLE MAINTENANCE

There are certain areas along the cable which should receive more attention than others, since some areas will usually be subjected to greater internal stresses, or to greater external forces and hazards. Critical points that should be considered for inspection would include the following: End attachments - Broken wires are a primary concern when inspecting end attachments on the cables. A single broken wire is usually reason to question continued use of the cable and more than one is usually sufficient cause for cable replacement. Broken wires may be more difficult to locate at the end fittings than in other sections of the cable.

Inspection sheaves - Each sheave should be periodically inspected. Sheaves should be inspected for the following:

A) Groove depth, width, and contour. E) Signs of wire rope contact with guards.

B) Groove smoothness. F) Sheave bearings and shaft.

C) Broken or chipped flanges. G) Out-of-round condition.

D) Crack in hubs. H) Alignment of sheaves.

CABLE MAINTENANCE

A wire broken under a tensile load (Ref: Figure A) that exceeds its strength is recognized by the “cup and cone” configuration at the fracture point (A). The “necking down” of the wire at this point shows that failure occurred while the wire retained its ductility. Shear - tensile fracture (B) occurs in wire subjected to a combination of transverse and axial loads. Fatigue breaks are usually characterized by squared-off ends perpendicular to the wire either straight across or Z-shaped (C & D).

CABLE MAINTENANCE

Because the internal wires and strands move against each other as the cable flexes, it is important that the cables are well lubricated with a penetrating type cable lubricant. The leveling cables wrap and unwrap on pulleys as will as roll across idler sheaves making it even more important that the cables be well lubricated in those areas.

In applications where the cables run across an elbow sheave, or a wear block, grease between the cable and sheave / wear block is the recommended lubricant.

CABLE MAINTENANCE

Travel Bounce - Booms that are not securely held down may bounce violently when the Hi-Ranger is in motion. The cable system responds to this bounce by alternately stretching and relaxing, resulting in wear and tear of the cable.

Overload - An overload, however small in relationship to the posted maximum platform capacity will accelerate the wear of the system and endanger operators. Under a heavy bearing load, the cable will be crushed against a sheave track. One or more individual preformed wires, usually an internal one, will break.

Lack of Lubrication - Internal friction will occur between strands, and/or external friction will occur with pulleys and sheaves, when a cable is dry or rusty.

CABLE MAINTENANCE

Cables have a normal service life and will deteriorate in due time, even when used under the most ideal conditions. Therefore, Hi-Ranger has established replacement intervals for all cables that must be followed.

All cables are subject to a mandatory five (5) year replacement with the exception of the three 1/4” cables at the platform sheave, if applicable. The mandatory replacement for these three cables is three (3) years.