Official Answer
Answer
Springs are classified by how they are loaded: compression springs are pushed shorter, extension springs are pulled longer, torsion springs are twisted about an axis, and constant-force springs uncoil a strip to deliver near-flat load over a long stroke. A wave spring belongs to the first group — it is a flat wire compression spring. Knowing where it sits in the family is what makes the selection quick: it competes with the round-wire helical compression spring on load, and with the Belleville disc washer on height, and it is chosen when neither of those two fits the cavity.
