more buoyant feel. History While coil springs were invented in the 15th century, they were not used in mattresses until the mid-late 19th century, following the use of upholstery coil springs in furniture and carriages. Microcoils were introduced in the early 21st century, and are a small part of the market. The bed coil spring was patented by Louis Andrew Vargha. Some modern feedback on coils within mattresses cast aspersions on some of its attributes such as abrasion on coils eventually culminating into prodding, and the audibility of the coils, as it may decrease privacy for intimate moments such as sexual activity. Manufacturers The mattress coil market is quite concentrated – the leading suppliers are Leggett & Platt (founded 1883) of Carthage, Missouri and AGRO International (founded 1948) of Bad Essen, Germany. Others include HSM (company) (formally Hickory Springs, founded 1944) of Hickory, North Carolina; Spinks (founded 1840) of Leeds, United Kingdom and Subiñas (founded 1959) of Mungia, Biscay province, Spain. See also Upholstery coil springs Box-spring References Mattresses Springs (mechanical)