Provided is a zipper chain. The zipper chain includes a plurality of chain portions arranged to face each other and engaged with each other at one point while making linear movements. Each chain portion includes a plurality of upper plates connected to each other; a plurality of lower plates arranged to respectively face the upper plates, respectively spaced apart from the upper plates, and connected to each other; a plurality of connecting portions each connecting one of the upper plates to a corresponding one of the lower plates and connecting adjacent upper plates among the plurality of upper plates or adjacent lower plates among the plurality of lower plates; and a plurality of protrusions respectively protruding from the plurality of connecting portions.

Provided is a zipper chain. The zipper chain includes a plurality of chain portions arranged to face each other and engaged with each other at one point while making linear movements. Each chain portion includes a plurality of upper plates connected to each other; a plurality of lower plates arranged to respectively face the upper plates, respectively spaced apart from the upper plates, and connected to each other; a plurality of connecting portions each connecting one of the upper plates to a corresponding one of the lower plates and connecting adjacent upper plates among the plurality of upper plates or adjacent lower plates among the plurality of lower plates; and a plurality of protrusions respectively protruding from the plurality of connecting portions.

A stable extension and retraction motion is realized in a robot arm mechanism including a linear extension and retraction joint. In the robot arm mechanism including the linear extension and retraction joint, the linear a extension and retraction joint includes an arm section, and an ejection section for supporting the arm section. The arm section includes a first connection piece string and a second connection piece string. The first connection piece string includes a plurality of first connection pieces. The second connection piece string includes a plurality of second connection pieces each having a substantially flat plate shape. The first connection piece string is joined to the second connection piece string to thereby constitute a columnar body. The columnar body is sent out forward from the ejection section. A guide roller for guiding the second connection piece string to the ejection section and keeping an engaged state of a linear gear provided on the second connection piece and a drive gear is provided behind the ejection section.

A purpose is to improve storability of a plurality of connection pieces coupled bendably. A robot arm mechanism includes a revolute joint and a linear extension and retraction joint. The linear extension and retraction joint includes a plurality of first connection pieces coupled bendably and provided with a hollow square cross section and a plurality of second connection pieces coupled bendably and each shaped like a flat plate. The second connection pieces are overlapped on the first connection pieces in upper part of the first connection pieces, thereby forming a columnar body by constraining bending. The columnar body is released when the first connection pieces and the second connection pieces are separated from each other. An ejection section forms the columnar body by joining the first connection pieces to the second connection pieces and supports the columnar body. The plurality of first connection pieces are coupled at an upper part and a lower part of each piece to be folded in a zigzag pattern and stored in a base with top faces of adjacent first connection pieces folded on top of each other and bottom faces of adjacent first connection pieces folded on top of each other alternately.

A purpose is to improve storability of a plurality of connection pieces coupled bendably. A robot arm mechanism includes a revolute joint and a linear extension and retraction joint. The linear extension and retraction joint includes a plurality of first connection pieces coupled bendably and provided with a hollow square cross section and a plurality of second connection pieces coupled bendably and each shaped like a flat plate. The second connection pieces are overlapped on the first connection pieces in upper part of the first connection pieces, thereby forming a columnar body by constraining bending. The columnar body is released when the first connection pieces and the second connection pieces are separated from each other. An ejection section forms the columnar body by joining the first connection pieces to the second connection pieces and supports the columnar body. The plurality of first connection pieces are coupled at an upper part and a lower part of each piece to be folded in a zigzag pattern and stored in a base with top faces of adjacent first connection pieces folded on top of each other and bottom faces of adjacent first connection pieces folded on top of each other alternately.

A purpose is to improve movement characteristics of a linear extension and retraction mechanism. A robot arm mechanism includes a revolute joint and a linear extension and retraction joint. The linear extension and retraction joint includes a plurality of first connection pieces coupled together bendably on a bottom plate side and provided with a U-shaped cross section, and a plurality of second connection pieces coupled together bendably and each shaped like a flat plate. A foremost one of the plurality of second connection pieces is connected with a foremost one of the plurality of first connection pieces. The first and second connection pieces, when overlapped each other, form a columnar body by being constrained from bending. The columnar body is relaxed when the first and second connection pieces are separated from each other. An ejection section forms the columnar body by joining together the first and second connection pieces and supports the columnar body. A linear gear is formed on a surface of a bottom plate of each of the first connection pieces. A drive gear is engaged with the linear gears of the first connection pieces overlapped to the second connection pieces in the ejection section.

A purpose is to improve movement characteristics of a linear extension and retraction mechanism. A robot arm mechanism includes a revolute joint and a linear extension and retraction joint. The linear extension and retraction joint includes a plurality of first connection pieces coupled together bendably on a bottom plate side and provided with a U-shaped cross section, and a plurality of second connection pieces coupled together bendably and each shaped like a flat plate. A foremost one of the plurality of second connection pieces is connected with a foremost one of the plurality of first connection pieces. The first and second connection pieces, when overlapped each other, form a columnar body by being constrained from bending. The columnar body is relaxed when the first and second connection pieces are separated from each other. An ejection section forms the columnar body by joining together the first and second connection pieces and supports the columnar body. A linear gear is formed on a surface of a bottom plate of each of the first connection pieces. A drive gear is engaged with the linear gears of the first connection pieces overlapped to the second connection pieces in the ejection section.

A linear extension and retraction mechanism includes a plurality of first connection pieces coupled together bendably; and a plurality of second connection pieces coupled together bendably, wherein back faces of the first connection pieces and back faces of the second connection pieces are overlapped each other, thereby generally forming a columnar body by constraining bending, and the columnar body is relaxed when the first and second connection pieces are separated from each other, the linear extension and retraction mechanism further including an ejection section adapted to support the columnar body.

A linear extension and retraction mechanism includes a plurality of first connection pieces coupled together bendably; and a plurality of second connection pieces coupled together bendably, wherein back faces of the first connection pieces and back faces of the second connection pieces are overlapped each other, thereby generally forming a columnar body by constraining bending, and the columnar body is relaxed when the first and second connection pieces are separated from each other, the linear extension and retraction mechanism further including an ejection section adapted to support the columnar body.

A unidirectionally bendable transmission chain is provided. At a first side thereof, an inner stop plate is fixed between a pair of inner chain plates at both ends of pin shafts, and an outer stop plate is fixed between a pair of outer chain plates at both ends of the pin shafts. Both ends of the inner stop plate are flush with axes of pin holes provided at both ends of the inner chain plates, and both ends of the outer stop plate are respectively provided with extensions beyond the outer chain plates; the extensions of the outer stop plate form a one-sided support for the inner stop plate to prevent the transmission chain from bending toward the first side, thus the transmission chain bends unidirectionally toward a second side opposite to the first side. A hoisting mechanism and a liftable roadblock having the above transmission chain are further provided.