HOISTGEARCASECOVER

the center pintle section to the intermediate sections. Check all bottom plates for buckling and indentations to make sure no localized high ground loading is occurring. Watch all vertical diaphragms, both radial and circumferential, for paint cracking or checking in lines. This condition indicates high stress pattern development. REPAIR

The basic repair procedure for the base is repair welding of cracked or damaged welds or plates. Use welding procedures as outlined in appendix. When repairing cracks do not add, reinforcing plates unless so advised by Bucyrus-Erie Service Department.

SWING RACK

Inspect the swing rack and pinion weekly to insure there are no bare metal spots or contact points, broken tooth ends, loose bolts or broken welds at back of rack. In particular, check for pitting, abrasion, scratching, spalling, and galling as shown in appendix under the topic, GEAR INSPECTION. All teeth should carry a good coating of protective lubricant. If during inspection a broken tooth is noted, shut down the machine immediately and do not operate the machine until the tooth has been repaired. For repair instructions for broken or cracked teeth, refer to appendix. WARNING: Continued operation ofthe'machine with one or more broken teeth in the swing rack could result in additional damage to the swing rack, swing pinions and swing machinery units.

REPAIR

Although uncommon, if complete cracking of a swing rack segment is noted, the rack segment can be replaced using the following procedure. Prior to initiating the repair, contact the Bucyrus-Erie Service Department so that the cause ofthe cracking can be traced. 1. Move the machine to a safe area with adequate space to perform the repair. 2. Swing the machine so the damaged rack segment lies behind a roller circle section not having an upper rail. Shut down the machine and tag the controls. 3. Remove the roller circle section completely as described under topic ROLLER CIRCLE. In-

stall ramps sloping down from the rail pad toward the damaged rack section (figure 2). I\. CAUTION: Each rack segment is ex.. tremelyheavy. so be sure the equipment used to handle the segment has sufficient capacity to safely perform the repair.

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4. Unbolt the rack segment from the base and with the selected equipment pull it over the ramps and off the base. 5. Repair or replace the damaged rack segment.

Reset the ramps and pull the new or repaired rack segment into place. Remove the ramps. 6. Insert 1 x 4 UNC capscrews in the tapped holes in the rack segment. Use the ca pscrews to level the rack segment. Insert shims, as needed, between the rack segments and rack pad.

Install the rack bolt and snug up. Check for proper alignment of the rack section to the mating sections. When properly aligned back off on the leveling capscrew and torque the rack bolts. 7. Weld the rack segment to the pad and then to ' the mating sections. The rack to pad weld is a 3/4 inch fillet weld. Be sure the vertical leg of the fillet weld is 3/4 inch as shimming could ("" affect the weld height. The inside vertical joint " weld is a convex butt weld. )

8. Replace the roller circle section as described in the topic ROLLER CIRCLE. 9. Lubricate the teeth of the rack segment and check the segment for proper operation by swinging the machine.

ROLLER CIRCLE

Inspect the roller circle weekly for severe pitting or spalling which generally indicates non-uniform loading, Small incipient pitting on the rollers, however, is not unusual. Also check for distructive roller wear in the contact area of the inside flange. If rollers are damaged, they should be removed immediately. If the roller cannot be replaced a t the time of removal, the good rollers should be redistributed so that they are equally spaced around the roller circle. Generally, 10% of evenly distributed rollers may be missing and not significantly effect the operation of the drag line. Also, the roller frames should be checked for warping or bending. Examine the upper and lower rails for pitting and spalling and that the chock and clamps are in place and tight. Check that the rails and rollers are being properly lubricated. "C