The Merriam Knapsack, Duluth Pack and Trapper Nelson Pack. Courtesy of the U.S. Patent and Trademark Office. Patented, May 21st 1878
Before there were backpacking packs there were knapsacks, which were packs with shoulder straps that lacked any structure. Henry Merriam submitted a patent in 1877 (patented the following year) for a pack for the United States Army that used sheet metal to rig the bag away from the wearer’s body. Merriam wrote the that the pack helped by, “reducing the number of separate equipments, lessening the weight to be carried, and at the same time disposing it more uniformly, and leaving the body of the soldier freer and less hampered by straps and other fastenings.” It ended up being discarded because it simply was too uncomfortable.