Attachment 1 - Statement of Work.pdf

Statement of Work (SOW) Crane Boom

Inspection/Teardown/

Reassembly 04/14/2022

Crane Boom Inspection Attachment 1

Statement of Work National Crane Boom

TABLE OF CONTENTS

1.0 Introduction 2

1.1 Background 2

1.2 Scope 2

1.3 Objectives 2

2.0 Requirements 3

2.1 Tasks 3

2.2 Deliverables 3

2.3 Schedule 4

2.4 Assumptions 4

3.0 Government Furnished Property 4

4.0 Security Requirements 4

1.0 INTRODUCTION/OVERVIEW

This SOW is to remove, disassemble, inspect all components, replace extension cables, reassemble and adjust the boom pads on four National Crane 600C boom.

1.1 BACKGROUND

Service is required by ASME 30.5 every five years or 3,000 hours. 90 LRS cranes are close to the five year mark. Without this work, the cranes must be taken out of service.

Complete actions In accordance with (IAW) National Crane Repair Manual or Air Force Technical Order 36C3-4-21-31, page 44 “If the boom has not been disassembled in the last three years, the boom is to be completely torn down to allow a thorough inspection of the extend and retract cables and extend and retract sheaves and pins.” Neither 20th Air Force (AF) nor Air Force Global Strike Command (AFGSC) will provide a waiver for the five year/3000 hour inspection on the boom, nor will they add a change for it in the local job guide. Warner Robbins Air Logistics Center (WR/ALC) also will not rescind the National Crane technical order (TO) inspection requirements.

1.2 SCOPE

1. Boom Disassembly

2. Maintain any portion of disassembled boom that is required

3. Inspection of inner components

4. Replacement of top and bottom pads

5. Replace all extend and retract cables with new set specified in National Crane Repair Manual or Air Force Technical Order 36C3-4-21-31

6. Calibrate as needed

7. Inspect all the wear pads, extend and retract sheaves and pins, cable sheaves, and hydraulic cylinder for any other repairs need. Reassemble the boom back together and install it back on the unit.

8. Test the operation and perform a load test to the unit.

2.0 REQUIREMENTS

2.1 TASKS

2.1.1 BOOM DISASSEMBLY

[For reference, front (tip) is sheave case end. rear (base) is winch mount end, left and right are viewed from rear to front.] Steps 1 through 3 apply to a boom that is to be disassembled with the 1st section and jib (if equipped) left on the crane.

2.1.1.1 Extend and set the outriggers.

2.1.1.2. Completely retract the boom and place it in a horizontal position.

2.1.1.3. Tag and disconnect the hydraulic lines to the telescope cylinder. Cap all lines and plug open ports.

2.1.1.4. Mark the location of the nuts which secure the 1/2/3 extend cables to the back of the 1st stage boom and to the back of the 3rd stage boom through the slots in the top of the 2nd stage boom to within 1/2" from the end of the threaded stud. Then loosen and remove the nuts which secure these 1/2/3 extend cables to the back of the 1st stage boom. Leave the cable ends draped inside the boom.

2.1.1.5. Loosen and remove two cap screws, lock washers and spacers which anchor the 1st stage extend cylinder rod to the base of the 1st stage boom.

2.1.1.6. Remove and tag four side wear pads with shims and one top wear pad from tip of 1st stage boom. Attach a sling or chain to the tip of the 2nd stage boom and pull the 2nd (with 3rd and 4th stage) out approximately one foot.

2.1.1.7. Remove and tag the cable guards that are bolted to the bottom of the first and second sections. Remove four cap screws that retain the bottom wear pads in the front of the first section. Remove four cap screws with lock washers which retain the 1/2/3 retract cable anchor to the bottom tip of the 1st stage boom. Pull the retract cable anchor assembly out and keep retract cables taut while pulling 2nd (with 3rd and 4th) stage out of 1st stage.

2.1.1.8. Place 2nd (with 3rd and 4th) stage on a suitable horizontal surface. Take care not to pinch or crush retract cables while lifting or supporting 2nd stage boom. If necessary, tag and remove wear pads and shims from base of 2nd stage boom.

2.1.1.9. Remove and tag the two grease tubes that lead from the retract sheave pin in the 2nd stage boom to the couplings in the back of the 2nd stage boom. Pull the retract/sheave pin (with retract sheaves and cable keepers) back out of its slots. Smooth out any burrs which may be present on flat ends of pin to eliminate sheave bearing damage when sheaves are removed from pin.

2.1.1.10. Remove the cap screw and lock washer that holds the angle bracket to the retract cable keeper in the base of the 3rd stage boom. Remove retract cable keeper with cables from lower base of 3rd stage boom. Store 3/2/1 retract cables, which are now free, in an area where they will not be damaged during further boom disassembly.

2.1.1.11. Remove four large nuts, two cap screws, and the 2/3/4 extend cable anchor assembly from the top base of the 2nd stage boom.

2.1.1.12. Remove two socket head shoulder bolts with flat washers from the extend cylinder anchor brackets at the center base of the 2nd stage boom.

2.1.1.13. Remove and tag wear pads with shims from front tip of 2nd stage. Attach a sling or chain to the 3rd stage boom and pull it out from the 2nd stage approximately one foot.

2.1.1.14. Pu11 the 1/2/3 extend cable sheave case assembly out from the top, tip of the 2nd stage boom and let the sheave case and cables rest on the top of the 3rd stage.

2.1.1.15. Remove four cap screws that retain the bottom wear pads in the front of the second section. Remove four, flathead, countersunk cap screws which retain the 2/3/4 retract cable anchor assembly to the bottom tip of the 2nd stage boom. Pull the retract cable anchor assembly out and keep the retract cables taut while pulling the 3rd and 4th stage booms out of the 2nd stage.

2.1.1.16. Place the 3rd and 4th stage booms on a suitable horizontal surface. Take care not to pinch or crush the retract and extend cables while lifting or supporting the 3rd stage boom. If necessary, tag and remove wear pads and shims from base of 3rd stage boom.

2.1.1.17. Finish removal of nuts retaining 1/2/3 extend cables in tubes at back of 3rd stage, then remove 1/2/3 extend cables and sheave case from top of 3rd stage boom. If required, remove four cap screws which retain extend sheaves in sheave case.

2.1.1.18. Remove and tag the two grease tubes that lead from the retract sheave pin in the 3rd stage boom to the couplings in the top of the 3rd stage boom. Pull the retract sheave pin (with retract sheaves and keepers) back out of its slot at the bottom base of the 3rd stage boom.

Smooth out burrs on the pin ends and remove sheaves and wear blocks from pin.

2.1.1.19. Remove the two cap screws and "T" tabs that hold the retract cable keeper in the bottom base of the 4th stage boom. Remove the cap screw and angle that holds the extend cable keeper in place. Remove the retract cable keeper from the bottom base of the 4th stage boom by sliding it completely to one side and rotating the other side up and out. Store the 4/3/2 retract cables which are now free in an area where they will not be damaged during further disassembly.

2.1.1.20. Remove two cap screws with lock washers and two keepers which retain the 3rd stage extend cylinder in the 3rd stage boom base. (It may be necessary to turn the second stage cylinder ears for access.

2.1.1.21. Pull the extend cylinder out while keeping 2/3/4 extend cables taut until the sheaves at the tip of the 3rd stage cylinder are within three feet of removal from inside the boom. At this time reach into the bottom base of the 4th stage boom with a hook and remove the 2/3/4 extend cable anchor block by sliding it out.

2.1.1.22. Remove the extend cylinder from the boom. Do not allow the sheaves or large rollers to fall off the pin which supports them. Remove 2/3/4 extend cables. Store cylinder and cable in a suitable place where they will not be damaged during further boom disassembly.

2.1.1.23. Remove side, top and bottom wear pads from the tip of the 3rd stage boom. Then remove the 4th stage boom.

2.1.2 ADDITIONAL MAINTENANCE, DISASSEMBLED BOOM

2.1.2.1. Clean all boom sections and inspect for wear, dents, bent or crooked boom sections, gouged metal broken welds or any abnormal conditions. Repair or replace as required.

2.1.2.2. Inspect all sheaves for excessive groove wear or abnormal rim wear. Replace as required.

2.1.2.3. Inspect all sheave bearings for excessive wear or cut l inner material if installed bearing diameter is .015 larger than pin diameter, bearing must be replaced. Any cut or gouge which causes the bearing liner to be distorted is cause for bearing replacement.

2.1.2.4. Clean and inspect all cable assemblies according to the wire rope inspection procedures in this section. Pay particular attention to any wire breakage at the end connections.

2.1.2.5. Replace cable assemblies as required. Lubricate all cable assemblies before reinstalling them in boom.

2.1.2.6. Inspect all sheave pins for nicks, gouges or pitting due to rust in the bearing surface area.

Replace if any damage is evident.

2.1.3 FOUR SECTION BOOM ASSEMBLY

NOTE: These instructions are to be used in conjunction with a special cable tensioning toot developed by NCC. The tool should assist with the boom assembly and speed up the final cable tensioning procedure. If the tool is not being used, when initially assembling threaded ends of cable, thread the first nut on past the flat in the cable so adjustments can be made later. Do not use Loctite on any cable threaded ends. Always use the two nuts provided and lock together.

2.1.3.1. Assemble sheaves into fourth section sheave case. Top sheave is to be installed to the left hand side of the boom with the spacer to the right hand side.

2.1.3.2. Install two top wear pads at back end of 4th stage boom. With Loctite 242 (blue), Loctite all pad mounting cap screws.

2.1.3.3. Install shims, if required, and four side wear pads at back of 4th stage boom. Shim according to calibration instructions in this section.

2.1.3.4. Install shim and two wear pads on the bottom rear of the fourth stage using Loctite 242 (blue) on the cap screws. Install 4th stage boom into 3rd stage approximately five feet. Install 3rd stage bottom front wear pads with Loctite 242 (blue) applied to the pad mounting cap screws.

Install side wear pads on front inside 3rd section. Install cable guide and related hardware on the top front of section 3. Push 4th stage completely into 3rd stage. Scribe a mark on the fourth section boom side plate indicating where the section bottoms out in the third section. This mark will be used during cable tensioning later.

2.1.3.5. Install and center sheave pin into 3rd stage extend cylinder butt plate. Make sure the grease holes in the pin are pointed toward the rod end of the extend cylinder. Tightly install the set screw and locknut to secure the sheave pin in the butt plate. Install bearings into extend cylinder sheaves and rollers if required. Coat surface of bearings with chassis grease and install sheaves on sheave pin. Install outer rollers. Wrap approximately 10 feet of 5/8 diameter cable around sheaves and install 2/3/4 extend cable anchor over cable button ends.

2.1.3.6. Support and install extend cylinder into 3rd/4th stage boom with flat top of cylinder anchor plate toward top of boom. Ensure cables are properly reeved over top and bottom of sheaves as they enter 4th stage boom. Push cylinder in far enough for sheaves to clear the cable anchor slot at bottom, back of 4th stage boom, then slide the 2/3/4 extend cable anchor block completely into this slot. Be sure cable anchor block is bottomed out in the slot. Pull the threaded cable ends until the cable buttons are bottomed out on the cable ^j block in the 4th stage boom, then slide the cylinder in close to its slot at the back of the 3rd stage boom.

2.1.3.7. Loop two of the 1/4 diameter retract cable assemblies (these are approximately 16 inches longer than the extend cables) around the retract cable anchor assembly, then tip and install it in the slots in the side plates of the 4th stage boom. The extend cylinder will have to be raised slightly for clearance. Once the anchor is in place install the two "T" tabs using cap screws and lock washers. Also mount the angle bracket to the 2/3/4 extend cable anchor using cap screw with Loctite 271 (red).

2.1.3.8. Assemble the retract sheaves with pin and keepers on the retract cables exactly as shown.

Be sure the couplings on the pin are pointed toward the tip of the boom and the cables do not cross, i .e. inside cable stays inside, 80 outside cable stays outside. Brush chassis grease in sheave bearings. Install bearings in double sheaves if required. Install the cables around the two double sheaves and install the keepers around each double sheave so the cables enter the top, exit the bottom and are encapsulated by the keeper as shown. Install flattened end pin through both double sheaves. Slide assembly into slots at back bottom of 3rd stage boom. Pull cables taut, again make sure they are reeved as shown and will not cross over one another when the 4th stage extends. Wire the loose cables to the bottom of the sheave case for easier assembly of 4th/3rd into 2nd stage. The nuts on the inside retract cables should be installed with 1-1/4" of thread protruding beyond the double nut on each side. The outside cables should have approximately 1" of thread protruding beyond the double nut. This measurement will be the same for both sets of retract cables.

2.1.3.9. Install the cable wear pad on the top of the extend cylinder barrel if required, then install the cylinder into the slots at the back of the 3rd stage boom with keepers, cap screws and lock washers. Now install the grease tubes to the retract cable sheave pin couplings and the couplings on the top of the third stage.

2.1.3.10. Stretch the two shorter, 1/4 diameter, 1/2/3 extend cables out, then bring threaded ends back together to form a loop and find the center of the cable length. Place these looped cable assemblies on top of the 3rd stage boom forming left and right looped cable assemblies. Place the sheave case assembly on top front of 3rd stage boom with its top bar up and forward. Slide left and right loops into left and right sides of sheave case assembly. Correctly install bearings in sheaves, install keepers in sheaves and slide keepers (and sheaves) into front of sheave case assembly. Bolt sheaves and keepers in sheave case assembly with cap screws torqued to the proper specifications. Then install the three triangular cable keepers using three cap screws and three lock washers. In order to make any early cable adjustments, the sheave case needs to be pulled up tight against the third section cable guide and wired in place. This is approximately its final position when the boom is assembled. Pull threaded cable ends toward back of boom.

Install threaded cable ends with nuts as shown into the tubes at the back of the 3rd stage boom.

Tighten the nuts until not less than 1" of the opposite thread end protrudes beyond the rear edge of the boom section top plate.

2.1.3.11. Install two top wear pads and two bottom wear pads at back of 3rd section boom.

Calibrate and install shims and four side pads at back of 3rd stage. Use Loctite 242 (blue) on all wear pad mounting cap screws. Be sure 2nd stage cylinder ears are horizontal, raise and support 3rd/4th stage and install two feet into the 2nd stage. Take care to keep bottom cables taut and all cables clear of pinch points created by slings and bottom pads. Install retract cable anchor in front bottom of 2nd stage with the retract cables in their appropriate slots. Run the cable nuts on only far enough to get a wrench on the flats of the cable. Take care not to cross cables. Install bottom wear pads in front of 2nd stage boom. Install side wear pads on front inside of 2nd section. Install cable guide, sheave case assembly, and related hardware on the top front of section. Push 3rd/4th stage into 2nd stage until it bottoms out against cylinder ears. Install flat washers and shoulder bolts with Loctite 271 (red) to retain the 2nd stage cylinder in the 2nd stage boom.

2.1.3.12. Install wear pad on top of 2/3/4 extend cable anchor assembly, then install 2/3/4 extend cable anchor assembly in slots at back, top of 2nd stage boom. Install spacers, washers and nuts on threaded cable ends. Run nuts on until the flats of the threaded cable ends protrude through the double nut. Be sure 1/2/3 extend cables are threaded over the top of the 2/3/4 extend cable anchor with wear pad. Mount the extend cable anchor with two cap screws.

2.1.3.13. Assemble the 1/4 diameter 3/2/1 retract cables as in step 8. Install the cable anchor at back bottom of 3rd stage boom. Assemble cables over double sheaves with keepers and pin and insert into slots at back bottom of 2nd section. The couplings in the pin must be angled toward the front of the boom. String cables toward front of boom. Be sure cables are not kinked or crossed. Mount angle bracket to cable anchor using cap screw, "lock washer, and Loctite 271 (red). Install nuts on end of cable and screw on until the flats on the thread protrudes through nut.

Install the grease tubes that run from the retract cable sheave pin couplings to the couplings on the back of the second stage.

2.1.3.14. Calibrate and install four side wear pads and shims at back sides of End stage. Install two top and two bottom wear pads with flathead cap screws and Loctite 242 (blue). Rotate 1st stage cylinder shaft so counterbalance valve is directly below shaft centerline, raise 2nd stage boom and install in 1st stage taking care not to damage external cables. Slide 2nd stage into 1st stage approximately two feet and install cable anchor assembly at bottom front of 1st stage boom with lock washers and cap screws with Loctite 271 (red). Install bottom wear pads in front of 1st stage boom. Make sure cables are not crossed, then finish installation of 2nd stage into 1st stage.

Anchor 1st stage cylinder rod to back of 1st stage winch mount with spacer, lock washer and cap screw that has been torqued and Loctite 271 (red).

2.1.3.15. After the extend group has been installed in the first section boom, use the special installation tool to install the cables to the rear of the first section boom. To do this assemble the tool around the rear plate of the first section as shown. Lay the cables in the slots of the tool keeping the cables in the slots, tighten the nuts on the tool to draw the cables up. The cables should be guided through the rear plate of the boom and nuts should be put on the cables before the tool is removed.

2.1.3.16. Install side wear pads with shims at the front of the 1st boom section. Use lock washers and nylon-insert cap screws with Loctite 242 (blue). Generally, shim side pads equally on each side of the boom, however, some boom straightening may be accomplished with shimming if required.

2.1.3.17. Install top steel spacer pad at front of the 1st boom section and top nylon pads and leadline cable guides at the front of the 1st boom section. Loctite cap screws with Loctite 271 (red).

2.1.3.18. Torque cable per the "Four Section Cable Tensioning" procedure.

2.1.3.19. After the four section cable tensioning procedure is completed, install cable covers on a11 threaded cable ends and cable guards on the bottom tip of the first and second boom sections.

2.1.3.20. During the boom assembly the fourth section was scribe marked indicating the position in which it bottomed out in the third. The same must be done for the second and third sections.

Extend the boom out approximately 12’ and then retract and hold pressure. While holding pressure, have someone scribe the side plates of the second and third sections indicating the position where each bottomed out. Get the measurement from the end of the first section boom to the outer edge of the lower jib mounting ear on the fourth section sheave case and record.

2.1.3.21. Let off the retract pressure and the sections will relax out. Once all the cables have been properly tensioned and are in balance, the sections should bottom out at the same time and stay retracted.

2.1.3.22. While holding retract pressure, tighten the 2/3/4 extend cables evenly. This should be done gradually and checked for results by extending 12’ and retracting again. Tightening these cables should pu11 out the fourth section slightly while pulling the third section in.

2.1.3.23. Once the third and fourth sections are within +/-1/16" of alignment with the scribe marks, retract the boom and hold pressure. Tighten the 1/2/3 extend cables until resistance is felt.

Tightening these cables will pull out the third section while pulling the second section in. Cycle out 12’ and retract and check original scribe marks. If necessary, repeat the tensioning procedure on both sets of cables until all three sections bottom out at the same time and remain.

2.1.3.24. Check the earlier recorded dimension between the front of the first section and the front edge of the sheave case mounting ear. This measurement should be within +/-1/32" of the original. NOTE: Moving to the retract cables, remember, the 3/2/1 retract cables directly oppose the 1/2/3 extend cables to ensure that the second and third stage booms extend and retract equally at all times. The 4/3/2 retract cables directly oppose 2/3/4 extend cables to ensure that the third and fourth stage booms extend equally at all times. Final torque on both sets of retract cables should be approximately 8 ft Ibs +/-2 ft Ibs.

2.1.3.25. Extend the boom out far enough so that adjustments can easily be made on the retract cables. Tighten the nuts at the front end of the second section. Start with the inside pair and adjust evenly until you start to feel some resistance. Move to the outside pair and tighten the same way. Do not draw the nuts up more than 3/8" without cycle testing. Cycle out 12’ and retract and hold pressure. The fourth section may bottom out first. If so tighten the large extend cables to approximately 40 ft Ibs +/-4 ft Ibs and cycle again. If the fourth section did not bottom out first and actually protruded out past the scribe mark, tighten the retract cables again until the fourth section bottoms out and remains.

2.1.3.26. Cycle out again so that the retract cables at the end of the first section boom can easily be adjusted. Tighten the nuts in the same sequence as the ones at the end of the second section.

Once you feel some resistance, stop, cycle out 12’ retract and check scribe marks. The second section may be drifting out slightly. Tighten the 1/2/3 extend cables to approximately 12 ft Ibs +/-2 ft Ibs and cycle. Continue this procedure until the second stays in without letting the third section go out.

2.1.3.27. The end result should be that the opposing forces on a11 cables have been balanced out.

The sections should extend and retract equally and stay retracted to within +/-1/32" of the original scribe marks. If not, the opposing cable forces may have to be fine adjusted again.

2.1.3.28. Cycle boom fully, check that all cables are torqued properly and that all sections are retracted completely, then add 2nd nut to all cables. Each threaded cable end must have two nuts locked together.

2.1.3.29. Reinstall 1st stage cylinder assembly with piston set, stop tube, packing gland and retaining ring into 2nd stage barrel. Be sure that the spiral ring expands completely and properly into the ring groove.

2.1.3.30. Cycle test cylinder to ensure leak-proof operation. Apply oil to 1st stage rod assembly through the holding valve. Support 2nd and 3rd stages as they extend and retract.

2.1.4. FOUR SECTION TOP/BOTTOM PAD REPLACEMENT2.1.4.1. ASSEMBLED

BOOM

Inspect top and bottom wear pads periodically for signs of abrasion or excessive wear. Excessive wear is wear in excess of 3/16 from original thickness (.75 on top pads, 1.00 on 1st and 2nd stage, .75 on 3rd stage bottom pads) or uneven wear such as the outside edge of the pad worn in excess of 3/32 deeper than the inside edge of the pad. If any of these conditions are found, the top and bottom pads may be replaced without disassembly of the boom.

2.1.4.2. TOP PAD REPLACEMENT

2.1.4.2.1 Retract the boom completely, then extend slightly to line up holes in back top of 1st, 2nd and 3rd stage booms. Remove the four flathead cap screws from the rear, top 4th stage pads through the aligned holes and the rear top second stage pads through the opening at the back top of the 1st stage boom. Remove the 4th stage wear pads through the back of 1st stage boom by sliding them back onto a flat surface such as a thin piece of steel or cardboard then pulling them out. Remove the 2nd stage wear pads through the opening at the back, top of the 1st stage boom.

2.1.4.2.2. Extend the boom approximately one foot to align the access holes to the 3rd stage wear pad mounting bolts through the 2nd and 1st stages. Remove the four flathead cap screws and slide the two sets of pads out through the back of the 1st stage boom by sliding them onto a flat surface thin plate or cardboard and then pulling them out.

2.1.4.2.3. Replace the pads in the reverse order starting with the 2nd stage pads and finishing with the 4th stage pads. Loctite all flathead mounting cap screws.

2.1.4.3. BOTTOM PAD REPLACEMENT

2.1.4.3.1. Lower the boom until the boom lift cylinder is bottomed out and extend the boom approximately six feet out.

2.1.4.3.2. Raise the 4th stage boom tip, until weight is removed from the bottom pads in the 3rd, 2nd and 1st stage boom.

2.1.4.3.3. Remove cap screws (two in each pad) which retain 3rd, 2nd and 1st stage bottom wear pad and remove and replace pads. Reinstall cap screws, Loctite and torque to proper tightness.

2.1.4.4 INNER WEAR PAD CALIBRATION

2.1.4.4.1. With a pair of inside/outside calipers, measure the inside width of the outer section (VL) at the front and back of the boom and record the smallest measurement. If the section has cylinder anchor bars, take a measurement directly in front of these bars.

2.1.4.4.2. With the inside/outside calipers, measure the outside width of the inner section at each side pad location. Record the largest measurement.

2.1.4.4.3. Measure the thickness of the wear pads and record

2.1.4.4.4. Subtract the largest outside width (W) of the inner section and the thickness of the two pads (t from the inside width of the outer section. Add shims as required (each shim is .03 thick) to tighten the pads so that there is .03, o9 clearance between the widest part of the inner boom and the most narrow part of the outer boom when shims and pads are installed. In some cases it will be necessary to have an unequal number of shims behind the pads at the top and bottom side pad locations.

2.2 DELIVERABLES

Perform all required technical order steps for the tasks listed above. Provide certification of completion of “Complete actions IAW National Crane Repair Manual or Air Force Technical Order 36C3-4-21-31, page 44 “If the boom has not been disassembled in the last three years, the boom is to be completely torn down to allow a thorough inspection of the extend and retract cables and extend and retract sheaves and pins.”

2.3 SCHEDULE

These will be scheduled sequentially based on contractor availability of parts and shop space.

Usual performance is one per week starting as soon as parts are ordered and available. Subject to the contractors workload and crane availability.

2.4 ASSUMPTIONS

Contractor is qualified to perform work on National Cranes

3.0 GOVERNMENT FURNISHED PROPERTY

None

4.0 SECURITY REQUIREMENTS

None