Patent attributes
A linear extension and retraction mechanism that is mounted in a robot arm mechanism includes: a plurality of first pieces having a flat plate shape which are bendably connected to each other at front and rear end faces; a plurality of second pieces having a groove shape which are bendably connected to each other at front and rear end faces of a bottom part, with the first and second pieces becoming linearly rigid when superposed, and the first and second pieces returning to a bent state when separated from each other; a head section which joins a leading first piece of the plurality of first pieces and a leading second piece of the plurality of second pieces; and a sending-out mechanism section including a plurality of rollers and for firmly superposing the first and second pieces and supporting the first and second pieces movably to front and rear. At least one groove section that extends from front to rear is formed in the surfaces of the first and second pieces that contact the rollers.