Connection piece, linear extension and retraction mechanism, and robot arm mechanism

A connection piece used for a linear extension and retraction mechanism, wherein:

• the connection piece is shaped like a flat plate;
• a linear gear is provided on a back face of the connection piece;
• and
• of a plurality of teeth making up the linear gear, a leading tooth and a rearmost tooth are provided in such a way as not to overlap each other when viewed along a center axis of the connection piece.

A robot arm mechanism equipped with a linear extension and retraction mechanism, the linear extension and retraction mechanism comprising:

• a first connection piece string, the first connection piece string including a plurality of first connection pieces coupled together bendably in a row, a linear gear consisted of a plurality of teeth arranged in a row being provided on a back face of each of the first connection piece;
• a second connection piece string, the second connection piece string including of a plurality of second connection pieces coupled together bendably in a row, a foremost one of the plurality of second connection pieces being connected with a foremost one of the plurality of first connection pieces, the first and second connection piece strings being joined with each other to constrain bending, thereby a columnar body being formed, the columnar body being relaxed when the first and second connection piece strings are separated from each other;
• an ejection section adapted to form the columnar body by joining together the first and second connection piece strings and support the columnar body;
• and
• a drive gear adapted to be meshed with the linear gears, wherein
• gear-end teeth located adjacent to each other across a junction between adjacent first connection pieces are provided in such a way as not to overlap each other when viewed along a center axis of the columnar body.