We claim the ornamental design for a ball-and-socket joint for tow bar, as shown and described.
FIG. 1 is a top, side and rear perspective view of a ball-and-socket joint for tow bar showing our new design;
FIG. 2 is a top, side and front perspective view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a side elevational view thereof, the elevational view of the opposing being a mirror image thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a front elevational view thereof;
FIG. 7 is a rear elevational view thereof;
FIG. 8 is an exploded top, side and front perspective view thereof; and,
FIG. 9 is a reduced side elevational view showing the ball-and-socket joint for tow bar in use; the broken lines depict environmental structure for illustrative purposes only and form no part of the claimed design.