Extension Springs

Extension springs stretch along the axis of their length under the application of a tension load. They are designed to absorb energy while expanding and to release it while contracting. When an extension spring is stretched, its change in length is proportional to the force it exerts. Therefore the further apart its ends are pulled, the greater its potential for work becomes. As such, extension springs are commonly used in applications that involve recycling the energy exerted in moving two parts of a system apart to bring them back in contact, as is seen on doors, hatches, and other types of moveable surfaces.

Stanley extension springs come in three loop types: Machine hooks, extended hooks, and cross over hooks. Wire thicknesses on these springs range from .012 - .188". Materials used include hard drawn wire, music wires like zinc coated music wire, galvanized music wire, tinned music wire, and preco-z music wire as well as stainless steel wires that include annealed stainless steel, 302 - 304 stainless steel, 316 stainless steel, 17/7 stainless steel, elgiloy wire, nichrome wire, nickel coated copper wire, oil tempered wire, and galvanized hard drawn wire.