4d is a side view of the safety mechanism of FIG. 64c shown after activation; [0096]FIG. 64e is a side view of a safety mechanism according to a thirtieth embodiment of the present invention shown prior to activation; [0097]FIG. 64f is a side view of the safety mechanism of FIG. 64e shown after activation; [0098]FIG. 64g is a side view of a safety mechanism according to a thirty-first embodiment o