The history of hairpin legs starts with them being invented by Henry P. Glass in 1941. Hairpin legs were a true war-time invention; their design limited the amount of material needed while keeping the strength of traditional legs. A true form meets function story.
Glass talked about the history of his hairpin legs in an interview:
[Russel Wright] liked my work and when, in 1941, he launched his campaign "American-Way," he honored me with an important assignment, to design a complete line of wrought iron furniture. I created a rather startling group of tables, chairs, sofas, etc., which commanded immediate and favorable attention in the trade press, particularly Home Furnishings Daily. Its editor-in-chief, Alfred Auerbach, coined the name "Hairpin Group" because of the shape of the steel wire legs. It was a great success, mainly in the media. I don't know how much of this furniture was actually sold in stores. It certainly created a trend. Countless furniture pieces of all kinds were put on hairpin legs for several years. Samples of this group are in the collection of several museums, such as the College for Applied Arts in Vienna and the Art Institute of Chicago.So, the first time hairpin legs were used on furniture was in 1941 as part of a Russel Wright American-Way collection. Although, some sources have the "Hairpin Group" being released in 1942. I wouldn't blame anyone for being off by a year in a live interview. There's also a good chance that Glass designed the hairpin legs in 1941 and the "Hairpin Group" wasn't released to the public till 1942.
And that release was indeed limited, as Glass hinted. Most American-Way products were produced in limited numbers. It's hard to say if this was by design in order to create a limited collection or if it was because of limited materials due to the war.
The American-Way "Hairpin Group" was manufactured by Molla, Inc, a New York-based company that way know for high-quality patio furniture. They used removable sailcloth covers for the chair covers and a type of metal that wouldn't oxidize in the salty outdoor air that blows across coastal patios.
Glass designed two separate American-Way collections that featured hairpin legs. One, which I believe to be the original "Hairpin Group," featured five different tables, three types of chairs and a settee. I can't find any info about what was included in the second collection. It was probably a similar lineup, as all original hairpin furniture was patio furniture. However, there is a sketch of a hairpin leg lounge chair from Glass, which I believe is part of the second collection.
It's interesting to note that the arms of the original "Hairpin Group" also had the hairpin leg form. Where as the second line seems to have moved to a full cloth arm.
You can see some other sketches of hairpin leg furniture in this video about Henry P. Glass' designs (at the :53 mark):
As Glass mentioned in his interview, there is indeed an example of the American-Way hairpin leg chair in the Art Institute of Chicago's collection, but they don't have an image of it online and it's not currently on display. They do have it listed as being made of cast iron with the dimensions of 34.25" x 18.75" x 19". However, I was able to track down a color photo of an original hairpin leg chair here.
Though Henry P. Glass has 52 patents in his name, the hairpin leg isn't one of them. In fact, he wasn't even created as the designer of "Hairpin Group" till many years after its release. But, Glass was right to say that "countless furniture pieces of all kinds were put on hairpin legs." Since their creation in 1941, Knoll and Eames have used hairpin legs and their use on mid-century furniture is so prolific that they're probably the most recognizable leg among mid-century modern furniture fans.
In tracking down the history of hairpin legs, I found out a lot of interesting info on Henry P. Glass. This isn't going to be the last time you see his name on this blog.