FIG. 1 is a perspective view of the pivot ball attachment with environment;

FIG. 2 is a perspective view of the pivot ball attachment of FIG. 1 without environment;

FIG. 3 is a front elevation view of the pivot ball attachment of FIG. 1;

FIG. 4 is a rear elevation view of the pivot ball attachment of FIG. 1;

FIG. 5 is a right side elevation view of the pivot ball attachment of FIG. 1;

FIG. 6 is a left side elevation view of the pivot ball attachment of FIG. 1;

FIG. 7 is a top plan view of the pivot ball attachment of FIG. 1;

FIG. 8 is a bottom view of the pivot ball attachment of FIG. 1;

FIG. 9 is a cross-sectional view of the pivot ball attachment of FIG. 1 taken along line 9—9;

FIG. 10 is a perspective view of an alternative pivot ball attachment;

FIG. 11 is a front elevation view of the pivot ball attachment of FIG. 10;

FIG. 12 is a rear elevation view of the pivot ball attachment of FIG. 10;

FIG. 13 is a right side elevation view of the pivot ball attachment of FIG. 10;

FIG. 14 is a left side elevation view of the pivot ball attachment of FIG. 10;

FIG. 15 is a top plan view of the pivot ball attachment of FIG. 10; and,

FIG. 16 is a bottom view of the pivot ball attachment of FIG. 10.

The broken lines shown in the figures for purposes of illustrating use and environment only and form no part of the claimed design.