overall: 99 cm x 135 cm x 56 cm; 38 31/32 in x 53 5/32 in x 22 1/16 in
United States: District of Columbia, Washington
From 1890 through 1950, information collected in the decennial United States census of population was punched onto cards and compiled using tabulating machines. At first the Bureau of the Census rented machines on the design of Herman Hollerith. Concerned by the high rental charges, it decided to develop tabulating equipment in its own shop.This tabulating machine was first used in the 1920 Census and then, after modification, in the 1930 Census.
The device accommodates 24-column cards. It has 60 four-position electromagnetic friction-driven counters with printing wheels and 50 electromagnetic relays, each with three contacts. The reading head contains individual wire brushes and contacts for each hole to be read. When a brush passes through a hole in a card, it encounters a contact and in turn activates the relays and counters.
L. E. Truesdell, <I>The Development of Punch Card Tabulation in the Bureau of the Census 1890–1940</I>, Washington: U.S. Department of Commerce, 1965.