US Patent 7350774 Long travel, high force combination spring

A long travel, varying spring rate combination spring includes two differing rate springs connected end-to-end in such a way that the lower rate spring is compressed until positive engagement of a plunger with an intermediate flange member occurs with the higher rate spring thereafter compressed. Each spring may be assembled separately and connected together with a coupling to create a combination spring, allowing various springs to be combined to meet the requirements of a particular application.