A posthole digger (the digger) is an agricultural implement manufactured by Alamo/SMC Corporation (SMC) designed, as its name implies, to dig holes in the ground for posts. The digger is tractordriven and has a driveline that connects at one end to the tractor’s power take-off (PTO), allowing the digger to draw power from the tractor’s engine. The digger is operated via controls near the tractor seat.

When the digger is engaged, the PTO rotates the driveline, transmitting power to the gearbox that, in turn, rotates a spiral auger that extends downward from an output shaft at the bottom of the gearbox into the ground. The digger comes equipped with several safety guards and shields, including a bell-shaped plastic shield manufactured by GKN Walterscheid (GKN) that is bolted to the gearbox.

This shield, which is made of durable high-density polyethylene, covers the gearbox input shaft and most of the U-joint, including the protruding nut and bolt. The digger’s operating manual provides numerous safety warnings about keeping all the digger’s safety shields in place, and several safety decals on the digger itself give warnings, including “

DANGER! SHIELD MISSING DO NOT OPERATE!”

and “KEEP ALL SHIELDS IN PLACE AND IN GOOD CONDITION.”

On October 1, 2004, Plaintiff’s stepfather borrowed the digger. Gary was not aware when he borrowed the digger that Smith had previously removed the safety shield from the gearbox and never replaced it. The following day, Gary was using the digger to dig holes for a backyard fence at his home.

Gary operated the digger from the tractor seat.

Gary asked plaintiff to assist him with the digger.

Plaintiff, then 16 years old, had never seen, used, or assisted in the operation of a posthole digger. While Gary was operating the digger, Plaintiff’s jacket caught in the rotating driveline, dragging her into the machine. By the time Gary disengaged the digger, plaintiff’s jacket and hair were wrapped around the driveline over the protruding nut and bolt at the U-joint connection. Smith later observed, as he unwound plaintiff’s jacket from the driveline, that its lower pocket had caught on the protruding nut.

Plaintiff’s right arm was severed above the elbow.

What defenses would you expect the manufacturer to use in this case?