Inspection of Vertical Transportation Equipment_11 pot

16.3 INSPECTION OF THE BRIDGE 16.3.1 General The bridge is that part of the crane consisting of the lower truck, hoist drive system, hoist drum, and aisle drive.. Hoist Drive System Ch

, MAGNETOROUE UNIT NOT REQUIRED)

MOTOR {PRAIODIC LUBRICATION

PERIODIC LUBAICATION NOT REQUIAED)

, NOT REQUIRED)

{PERIODIC LUBRICATION NOT ATOUIRED}

WHEEL BEARINGS 14)

PG EVERY 3 MO}

ROLLERS MPG (EVERY 3M)

WHICH CONTACT ROLLERS

EVERY 3M0))

CHAIN AND SPROCKET (Lu im BRICATE DIRECTLY WITH BRUSH EVEny

and other weer points every

16.1.4 Applicable Safety Standards

There is no safety standard written specifically for this type of equipment Section 5

GENERAL SAFETY STANDARDS ANSI/ASME B20.1 Safety Standards for Conveyors and Related Equipment and ANSI A10.5 Safety Requirements for Material Hoists could be used for

16.2 INSPECTION MADE FROM INSIDE CAB

16.2.1 General Safety Precautions

Visually inspect the crane's runway and adjacent storage racks for personnel and/or objects in the aisle or protruding from the storage bins Determine that all loose items such as tools or materials are removed from the carriage before attempting operation Inspect the crane's controls for any markings or other methods indicating that the crane is not to be operated Such markings may mean that the crane is inoperative or in the process of being repaired Place a sign on the disconnect switch stating that the crane is being inspected Determine that all the guards are in

place

16.2.2 Enclosure

Determine that the cab enclosure is structurally sound and securely fastened Examine

lighting fixtures to determine whether they are securely fastened and have required protection Determine that sufficient illumination is provided Determine that a fire extinguisher is properly mounted and available Open the cab gate and determine that the cab will not move with gate open Determine that a seat belt is provided for the cab operator Determine that a lifeline is provided for the cab operator if evacuation is necessary, from the crane, when in an elevated position

16.2.3 Operation

Check controls for proper identification (See Figure 16-5) Depress the stop switch and note whether the crane will operate Movement of the joystick should not move the crane unless both foot switches and the hand

16-6

ih EA CRANE SAFETIES A grant

BY PASS " et

SHUTTLE SHUTTLE | | i

RIGHT i ic J0VSTI(K is °

SHUTTLE SELECT

2 2 RTUNN (NEARFAR) NÓ SHUTTLE

TO CENTER SHUTTLE \ SIDE "A

operated safety interlock control are in the operating positions With the crane running, release any, either or both of the foot switches or the safety interlock All crane motions should stop It will be necessary to release both foot switches as well as the safety interlock and the joystick master before motion can be resumed With the foot switches and the safety interlock in

operating position, place the joystick control in the full or hoisting direction The platform should decelerate from full speed to slow speed and automatically stop at the upper limit

Reverse the direction and check the lower limit With the foot switches and the safety interlock

in Operating position, place the joystick control in full forward position The crane should

decelerate and stop at the end of the aisle Reverse the direction and check the reverse aisle limit switch

16.3 INSPECTION OF THE BRIDGE

16.3.1 General

The bridge is that part of the crane consisting of the lower truck, hoist drive system, hoist

drum, and aisle drive

16.3.2 Guides

Determine that the floor mounted guide rail is free of debris Check all lower guide rollers for worn or damaged wheels, bearings or shaft pins (See Figure 16-6) Inspect the wheels for cracks or chipping Inspect the wheels for flat spots and any unusual wear patterns or markings Check the wheel bearings for adequate lubrication Inspect the wheels for excessive float

Wheel float is the amount the wheel can move across the rail The allowable wheel float is approximately 1/8 inch If any of these conditions exist, the wheels must be repaired or replaced

16.3.3 Hoist Drive System

Check the brake linings for wear, and the air gap for proper spacing Check the mounting bolts to insure they are tight Check the hoist drive system (See Figure 16-7) The hoist drive

system consists of a motor, gear case, holding brake, load brake and hoist drum The hoist drive

system serves to raise and lower the carriage by wire ropes Hoisting power is provided by an

AC wound rotor type motor driving the rope drum through a reduction gear box A magnetorque load brake is employed to help control the speed of the hoist motor A spring-set shoe type motor brake is used to stop the motor This motor brake holds the hoist system in position until power is reapplied Check the motor bearings for proper lubrication and vibration due to wear Check motor brushes for adjustment or replacement and the slip ring for reconditioning Check the gear case for proper oil level, using the visual oil level indicator

16-8

HOIST DRIVE MOTOR

MOTOR MOUNTING

ADAPTER

BRAKE WHEEL

The oil level should not exceed the level indicator If the gear case is overfilled it will not retain the excessive oil and will leak onto other components (See Figure 16-8) Check the gear for excessive backlash and possible excessive shaft end play

16.3.4 Hoist Drum

The hoist drum is a machined circular casting mounted on the side of the gear case The drum

is used to take up and let out the wire ropes that raise and lower the crane carriage The hoist drum should be examined and tested with light blows from a hammer If the resulting sound from the blows is dull and flat unlike the ring given by sound metal, the hoist drum should be examined carefully for cracks The hoist drums are irreparable items If the drums have any

clicks, new drums must be installed

16.3.5 Wire Rope or Cable

16.3.5.1 General All wire rope will eventually deteriorate to a point where it is no longer serviceable There are three basic causes of wire rope deterioration They are:

is the axial distance along the rope in which one strand makes one complete turn around the rope The inspector should pay particular attention to the following:

a Internal wear caused by grit penetrating between the strand and wires

b Kinking

c Lubrication

d Corrosion

16-11

END PLATE

DROM

SHAFT ARMATURE

NUT BEARING RETAINER

BEVELED BRAKE SHAFT PINION

SHAFT

BEARING RETAINER HOIST ORUM

INPUT PINION OIL PUMP

BEARING RETAINER BRAIN PLUG

FIGURE 16-8

Hoist Drive Gear Case Assembly

16-12

e Number of broken strands per lay

f The manner in which the fittings are attached

g The condition of the sheaves over which the rope must pass, including sheave alignment

h The amount of wear on the outer wires

Any evidence of serious rope deterioration from corrosion should cause consideration to be given

to immediate replacement of the rope More than one strand should be cause for caution Breaks occurring in the valley between adjacent strands are generally a warning of an abnormal

condition, justifying caution Any broken wires at the dead end of a cable should be cause for cutting off a section Preferably at least three feet beyond the broken wires Refasten the rope

If the rope is not long enough, use a new piece of rope Any of the following conditions should cause the inspector to question the remaining strength of a rope, and to give consideration to the possibility of discarding the rope:

a If the core shows through more than one pair of strands

Ss If kinking damage is severe

c If there is evidence of improper lubrication, combined with other defects

d If wire has come in contact with an electrical circuit or has been subjected to overheating

e If there is serious reduction in rope diameter

f If there is evidence of "bird-caging" This increased diameter is usually caused by the sudden releasing of a heavy load while the rope is twisted

g If there are numerous broken wires or as many as three adjacent broken wires in one rope

lay

16.3.6 Inspection Of The Broken Rope Safety Device

(See Figure 16-9) The function of the broken rope safety device is to prevent the carriage from free-falling in the event of a broken (or slack) hoist cable Sliding wedges are used to

"Jam" the carriage against the mast to prevent it from free-falling one complete installation is found on each side of the carriage Actuation of the slack cable limit switch occurs in

16-13

FIGURE 16-9

Typical Broken Rope Safety Device

16-14

conjunction with the engagement of the wedges The switch is normally held closed and opens

as the associated link is pivoted by its spring Opening the switch contacts breaks the circuits to the hoist motor contractors Simulate a slack or broken rope condition as follows:

a Position a suitable hydraulic floor jack directly under a structural part of the platform

b Lower the platform onto the jack

c With the jack, raise the platform until a slack cable condition is achieved

d Release the jack so it no longer supports the platform

e The broken rope safety device shall prevent the platform from falling

f To reset the broken rope safety, depress and hold the crane safeties bypass switch and place the joystick master in the hoist direction

g Check the hoist drum to insure that the cable has not jumped any grooves

16.4 INSPECTION OF THE AISLE DRIVE

16.4.1 General

The aisle drive system consists of a motor, gear case, motor brake, load brake, drive wheel and

idler wheel (See Figures 16-10 and 16-11) Motor torque is transmitted through the reducer gear case to the flangeless drive wheel, which drives the entire stacker along the single rail mounted

on the floor Speed control is achieved by varying the excitation current to the drive motor field and the magnetorque load brake The holding brake, which is a disc type brake, serves to bring the crane to a complete stop and to hold the crane in position This brake is spring-set and

MOTOR MOUNTING ADAPTER

MAGNETORQUE ELECTRIC LOAO BRAKE AISLE DRIVE

GEAR CASE

AISLE DRIVE DISC TYPE MOTOR

MOTOR BRAKE |

AISLE DRIVE WHEEL

FIGURE 16-10

Aisle Drive System

16-16

OlL LEVEL GAUGE 4

16.4.3 Gear Case

Check the gear case for proper oil level, using the visual oil indicator The oil level should not

exceed the level indicator If the gear case is overfilled, it will not retain the excessive oil and

will leak onto other components (See Figure 16-10) Check the gear for excessive backlash and possible excessive shaft end play

16.4.4 Wheels

Check the aisle drive wheel for cracks or chipping Inspect the wheels for flat spots and any unusual wear patterns or markings Inspect the wheel bearings for adequate lubrication

16.4.5 Magnetorque Load Brake

The magnetorque load brake transmits braking force by means of electromagnetic fields (See Figure 16-10) There are no mechanical connections between the rotating unit and stationary members At periodic intervals, depending on the operating environment, the magnetorque must

be either vacuumed or blown out with dry, compressed air (50 psi maximum) to remove

accumulated dirt and dust in the interior Determine that the ventilation openings are clear Determine that no dirt or dust has accumulated in the interior Check the bearings for proper lubrication

16.4.6 Inspection of Motor Brake

The aisle drive system employs a disc-type motor brake as a holding brake This brake is spring set and electrically released No lubrication is required on these brakes Oil or any other lubricant applied to parts of the brake may interfere with proper, safe operation of the brake, especially if the oil comes in contact with the disc plates, back plates or friction discs Check the

brake for evidence of mechanical failures, misalignment or other defects Check that the friction

discs are clean, free of oil, and not excessively worn Examine the discs for signs of warpage and for reduced size due to wear Discs worn to approximately 3/16 inch thick or less must be

16-18

16.5.2 Inspections

Inspect the condition of the main line switch before inspecting any part of the controller opening the main line switch should remove all power from the controller Examine all relays,

switches, contactors, control circuit rectifiers, transformers, capacitors, reactors, etc Any

excessively worn or burned contacts, broken connectors, broken or cracked resistors, or tubes

should be replaced All fuses should be one time fuses and should not have any shorting wires Check for cleanliness and for accumulation of combustible materials on any parts

16.6 INSPECTION OF THE CARRIAGE

16.6.1 General

The carriage serves as the local carrying medium, transporting material to and from storage locations (See Figure 16-12) It is raised and lowered between the masts by means of wire ropes reeved to the hoist drums via the cranes upper end tie Guide rollers are provided on each side of the carriage, allowing it to move up and down the mast with a minimum of friction A number of limit switches and photo-electric scanners are used on the carriage assembly, to monitor the movement of the crane and the position of the load

Inspect the side shifter assembly (See Figure 16-14) The side shifter or shuttle is a

telescoping device mounted on the carriage and extending in either direction in order to place or retrieve a load Examine the sprockets and chains for signs of wear, misalignment, or other defects

16-19