Spring-supported crankshaft coupling structure for use in an engine

A spring-supported coupling device (1) used in an engine and coupled between a piston (A) and a crankshaft (B) is constructed to include, a first connector (11) pivoted to the piston (4), a second connector (12) pivoted to the crankshaft (B), a rod member (13) coupled between the first connector (11) and the second connector (12) and axially movable relative to the first connector (11) and the second connector (12), and a spring member (14) axially compressibly connected between the first connector (11) and the second connector (12) around the rod member (13).