Mechanical term for a central rotating rod or spindle that transmits motion or supports parts. 心棒 is the core shaft inside a machine or device.
central figure; core member; linchpin
Figurative use for a person who is the central pillar or driving force of a group or organization.
The shaft of this machine has bent.
Attach the material to the lathe's mandrel.
He is active as the central figure of the team.
That person is the linchpin of the company.
Compound of 心 (しん, 'core, heart') and 棒 (ぼう, 'rod, stick'). The literal meaning is 'core rod', which developed into the mechanical sense of a central shaft and later the figurative sense of a central person.