Compression Spring Bumpers

A subtype of Spring Bumpers that uses a helical compression spring as its primary repelling force. When the ball strikes the Bumpers cap, the spring compresses and snaps back, launching the ball away purely through stored mechanical energy. Stoner Manufacturing Company’s Super-Zeta (1938) is among the earliest machines to feature the design. While modern Pop Bumpers also contain compression springs to reset their solenoid plungers, the historical meaning — a spring that directly propels the ball without electrical power — is the defining characteristic for cataloging purposes, placing these bumpers squarely in the Electromechanical and pre-electronic eras.