Multi-directional multi-joint turning piece and display device thereof

A multi-directional multi-joint turning piece, configured to connect a first display module and a second display module and to provide the first display module and the second display module to unfold or fold each other, comprising a first coupling piece, a first turning piece, a second turning piece, a third turning piece, and a second coupling piece, wherein the first coupling piece is connected to the first display module and the second coupling piece is connected to the second display module, the first coupling piece is pivoted to the first turning piece, the first turning piece is pivoted to the second turning piece, the second turning piece is pivoted to the third turning piece, and the third turning piece is pivoted to the second coupling piece, and

• wherein the first coupling piece and the first turning piece are pivoted forward or backward to each other, the first turning piece and the second turning piece are pivoted forward or backward to each other, the second turning piece and the third turning piece are pivoted forward or backward to each other, the third turning piece and the second coupling piece are pivoted forward or backward to each other, when the first display module and the second display module are unfolded or folded,
• wherein one end of the first coupling piece is provided with a first through-hole for connecting one end of the first turning piece, the other end of the first turning piece is provided with a second through-hole for connecting one end of the second turning piece, the other end of the second turning piece is provided with a third through-hole for connecting one end of the third turning piece, the other end of the third turning piece is provided with a fourth through-hole for connecting one end of the second coupling piece, and
• wherein the multi-directional multi joint turning piece further comprises a first plug-in piece, wherein the first coupling piece includes a first connecting portion, the first connecting portion is a rectangular structure with a front and a rear symmetrical panels having a first spacing between the front and the rear panels, the first connecting portion is disposed at one end of the first coupling piece, the first turning piece is a rectangular structure including a second connecting portion and a third connecting portion, the second connecting portion is a rectangular structure with a first thickness, the second connecting portion disposed at one end of the first turning piece, the third connecting portion is a rectangular structure with the front and the rear symmetrical panels having a second spacing between the front and the rear panels, the third connecting portion is disposed at the other end of the first turning piece, and the first turning piece has a second thickness, the first thickness is smaller than the second thickness, the first thickness is smaller than the first spacing, the first coupling piece is connected with the first turning piece by the insertion of the second connecting portion into the first connecting portion, the first plug-in piece is inserted into the first through-hole, the first coupling piece is pivoted to the first turning piece, and the first plug-in piece is used as a pivot.