Fabricated Plates can Enhance the Operation of the Powered Access Ladder for Certain H-Series Wheel Tractor-Scrapers {0679, 7254} Caterpillar

Wheel Tractor Scraper

621H (S/N: DBK1-UP; EAZ1-UP)

623H (S/N: DBF1-UP)

627H (S/N: DBW1-UP)

Description Of Change: Fabricated plates can enhance the operation of the powered access ladder for certain H-Series Wheel Tractor-Scrapers. The fabricated plates will help to make the powered access ladder more robust and resistant to damage.

Adaptable To: If the machine is equipped with a powered access arrangement, the new fabricated plates are adaptable to the following machines:

• DBK1,102

• EAZ1,115

• DBF1,106

• DBW1,302

Fabrication Procedure

Fabricate the two plates (one left and one right) out of 3 mm (0.11811 inch) steel plate using the dimensions shown in Illustration 1 and Illustration 2.

Illustration 1	g06028672
Fabricated plate (1) ( AA) 111.6 mm (4.393 inch) (AB) 227.7 mm (8.964 inch) (AC) 346.5 mm (13.641 inch) (AD) 5 mm (0.196 inch) Radius (four places) (BA) 3 mm (0.11811 inch) (BB) 45 mm (1.771 inch) (BC) 189.9 mm (7.476 inch) (BD) 6 mm (0.236 inch) Radius

Illustration 2	g06028778
Fabricated plate (2) ( CA) 111.6 mm (4.393 inch) (CB) 227.7 mm (8.964 inch) (CC) 346.5 mm (13.641 inch) (CD) 5 mm (0.196 inch) Radius (four places) (DA) 3 mm (0.11811 inch) (DB) 45 mm (1.771 inch) (DC) 189.9 mm (7.476 inch) (DD) 6 mm (0.236 inch) Radius

Installation Procedure

1. Prepare the machine for maintenance.

   1. Move the machine to a flat and safe work area.

   2. Lower all implements to the ground.

   3. Place the parking brake switch in the ON position and shut off the engine.

   4. Chock the wheels.

2. Extend the powered access ladder to the down position.
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   Illustration 3	g06028855
   View of the rear of the powered access ladder (1) Fabricated plate

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   Illustration 4	g06028852
   View of the front of the powered access ladder (2) Fabricated plate

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   Illustration 5	g06028909
   (1) Fabricated plate (AA) 41.2 mm (1.622 inch) (AB) 570 mm (22.440 inch) (AC) 200.7 mm (7.901 inch) (AD) 258.6 mm (10.181 inch)

3. Locate plate (1) and plate (2) onto the ladder.

   Note: The same dimensions are used on both sides of the ladder.

4. Prepare the area for welding. Remove all paint, dirt, oil, and debris.

   Note: Refer to Special Instruction, REHS1841, "General Welding Procedures" prior to performing any welding on the machine.

5. Prior to final welding the plates, tack weld the end of each plate in the correct location. Ensure that there is clearance between the handrail and the plate when the ladder is in the closed position.

6. Weld plate (1) and plate (2) to the ladder group by using a skip 3 mm (0.118 inch) fillet weld every 50 mm (1.968 inch).

7. After the welding has been completed, repaint the area, as needed.

   Note: Plate (1) and plate (2) should be painted black.