Marshall coils, also known as encased coils or encased springs (most commonly known in North America as pocketed springs), are component parts of a mattress in which each coil is separately wrapped in a textile material.
Marshall coils were invented in 1899 by Canadian-born James Marshall, a machinist and engineer who was born near Haldimand, Ontario, Canada. He received a Canadian patent in 1900 for his unique invention. He received patents in the United States and United Kingdom. Marshall established the original Marshall Mattress company. He subsequently licensed patent rights to this design for the United Kingdom to his former employees. This company operated under the name of Marshall Sanitary Mattress Company until the early 1930s, when they changed their name to VI-Spring. James Marshall established the Marshall Mattress Company in Toronto, Canada, which has continued to operate for over 119 years. In January 2019, the Flex Group acquired Marshall Mattress from owners, the Warner family to continue the tradition of handcrafted quality mattress construction.
Marshall conceived of a mattress whereby internal independent springs would provide both support and comfort within the mattress itself. Marshall produced pre-compressed cylindrical coil springs, each sewn inside an individual cotton fabric pocket, which provided uplifting support on its own. When fitted together, the coils became an independent suspension system that contoured to each person's form and weight, providing unsurpassed support and comfort. When upholstered, a finished Marshall mattress aims to reduce physical pressure under the sleeper, and claims to relieve it as well. Marshall's pocket spring-filled mattress system became the original worldwide standard for spring-filled mattress construction.
- Marshall, James. "CA 68628." Canadian Intellectual Properties Office. Canadian Intellectual Properties Office, n.d. Web. 5 May 2014. <http%3A%2F%2Fbrevets-patents.ic.gc.ca%2Fopic-cipo%2Fcpd%2Feng%2Fpatent%2F68628%2Fsummary.html%3Ftype%3Dnumber_search>.
- Careless, J.M.S. "Partners in Progress - Marshall Ventilated Mattress Co. Ltd." ONTARIO: A Celebration of Our Heritage. Missisauga: Canadian Heritage Gallery, Copyright © 1991, 1992 and 1993. 384-85. Print
- Warner, Bradley. "Our Company - Marshall Mattress." Marshall Mattress - Company
- "Marshall Mattress - Inventor of the Pocket Coil Spring Mattress". marshallmattress.com. Retrieved 2018-01-03.