Trailer jacks are designed to withstand extreme vertical loading but are often subjected to unforeseen lateral loading conditions as the user attempts to maneuver the trailer onto or off of a trailer hitch. In many popular trailer jack designs, these lateral forces act on a single snap ring, or retaining ring, which holds the jack in place on the trailer. Failure of this snap ring could allow the tongue of a loaded trailer to fall to the ground, potentially injuring an unsuspecting user.
In cases in which a trailer jack becomes separated from the trailer, the investigation often focuses on the condition of the snap ring and whether or not it had been properly installed. Force analysis and exemplar testing can further determine the lateral loading conditions necessary to separate the trailer jack from the trailer.