Before the 19th Amendment to the US Constitution was ratified, the right of a woman to vote was up to the individual states. In Kentucky, women could vote as early as 1838, but that only applied to widows with children, and only on school issues. By the beginning of the 20th century, the laws governing a woman's vote were a patchwork across the country, and even in states where women could cast a ballot, they often couldn't vote in all the races up for grabs. Several inventors looked at the problem of separate ballots and came up with solutions. Lenna R. Winslow got a patent for a voting booth that separated voters by sex, and presented the "proper" ballot to each voter.
Voting machines were not new when Winslow came up with his creation. The first voting machine patented in the United States dates to 1875—a simple system with a series of buttons, one per candidate. Winslow’s invention went beyond regular tabulation and tallying, though. His voting machine—essentially an analog computer—recognized if the voter was a man or a woman and allowed them to vote accordingly.
The machine was actually two units: a large voting booth with two doors and the actual hardware for casting ballots and counting votes. The two doors were key to this setup: men used one entrance, marked “Gents,” while women used the other, labeled “Ladies.” A system of levers and switches were activated depending on which door was used, instructing the voting machine on whether full voting or only partial was allowed.
Winslow was not the only one who came up with inventions to make restricted voting easier. Too bad those patented devices were sent to the scrap heap in 1920 when women achieved the right to vote in all elections. Read about the technology used to restrict women's votes at Smithsonian.