2009/04/27 Preferred Positions for Mechanically Attached Wear Plates (MAWPS) {6100, 6120, 6820} Caterpillar

It has been stated that the Mechanically Attached Wear Plates (MAWPS) can be mounted in any position on earth moving structures that require protection from abrasion. However, one of the positions allows cover loads to be directed against the retainer. Exceptionally high cover loads could damage the retainer. Exceptionally high cover loads can also bend the retainer. A bend to the retainer can result in the following:

• Difficulty in removal of the retainer

• The loss of a cover due to the breaking of the retainer

Illustration 1	g01891874
This illustration shows a base plate with a retainer. (1) Retainer (8) Cover dovetail

Illustration 2	g01891953
(2) Impact from the cover dovetail

Illustration 3	g01892083
(3) Crack on the retainer (4) Distorted portion of the retainer

Usually, rotating the base 180 degrees will provide adequate support for the contact between the cover dovetail and the base. There is an application with large loader buckets when rotating the base 180 degrees may not prevent damage to the retainer. This application is back dragging, in order to clean the floor of the pit. Even though the retainer is away from the bucket loading forces, back dragging changes the direction of the forces on the cover. This will cause the retainers to get loaded.

Illustration 4	g01893773
(A) Bucket forces on cover and retainer during loading (5) The retainer is mounted in the forward position.

Illustration 5	g01893814
(B) This shows the load on the cover and the retainer when the bucket is back dragging. (6) The base is rotated 180 degrees in order to stop the bucket loading forces on the retainer.

Illustration 6	g01894178
(7) Preferred base side position on loader

Illustration 7	g01894393
(C) This shows the minimum clearance between covers to be 51 mm (2 inch).

The best load characteristics can be achieved by positioning the base at 90 degrees and allowing at least 51 mm (2 inch) clearance for the covers to be installed and removed.