Folding/unfolding mechanism, frame and table having same

A frame comprising:

• a first longitudinal bar disposed at a first side of the frame;
• and
• a second longitudinal bar disposed at a second side of the frame and substantially parallel to the first longitudinal bar;
• wherein each of the first and second longitudinal bars comprises a first bar and a second bar pivotally connected with each other, and
• wherein for at least one of the first and second longitudinal bars, the first and second bars are pivotally connected with each other by a folding/unfolding mechanism comprising:
• a first coupling piece fixed at a proximal end of the first bar, wherein the first coupling piece comprises a first hole and a first slot above the first hole, wherein the first slot has a closed bottom and an open top;
• a second coupling piece fixed at a proximal end of the second bar, wherein the second coupling piece comprises a second hole and a second slot above the second hole, wherein the second slot has a closed bottom and an open top;
• a third coupling piece comprising a third slot having a closed bottom and a closed top;
• a first rod passing through the first hole of the first coupling piece, the second hole of the second coupling piece, and the third slot of the third coupling piece, wherein
• the first and second coupling pieces are rotatable with respect to each other around the first rod, and
• the third coupling piece is movable with respect to the first rod between a first position where the first rod is at the bottom of the third slot of the third coupling piece and a second position where the first rod is at the top of the third slot of the third coupling piece;
• an elastic member disposed in an interior of the third coupling piece between the first rod and a bottom cover of the third coupling piece;
• and
• a second rod integrally formed or coupled with a top portion of the third coupling piece, and movable together with the third coupling piece, wherein
• when the second rod is disposed in both of the first slot of the first coupling piece and the second slot of the second coupling piece, the first and second coupling pieces are restricted from rotating with respect to each other,
• when the second rod is released from any one of the first slot of the first coupling piece and the second slot of the second coupling piece, the first and second coupling pieces are rotatable with respect to each other, and
• the elastic member exerts a force on the first rod and the bottom cover of the third coupling piece, thereby positioning the third coupling piece at the second position where the first rod is at the top of the third slot of the third coupling piece.

A frame comprising:

• a first longitudinal bar disposed at a first side of the frame;
• a second longitudinal bar disposed at a second side of the frame and substantially parallel to the first longitudinal bar;
• a first lateral bar disposed at a third side of the frame and having a first end pivotally connected with the first longitudinal bar and a second end pivotally connected with the second longitudinal bar;
• a second lateral bar disposed at a fourth side of the frame and having a first end pivotally connected with the first longitudinal bar and a second end pivotally connected with the second longitudinal bar;
• a plurality of legs, each having an end fixedly connected with the first or second lateral bar;
• a plurality of oblique bars, each having a first end and a second end, wherein the first end of each respective oblique bar in the plurality of oblique bars is pivotally connected with a corresponding leg in the plurality of legs;
• and
• a plurality of sliders, each slidably coupled with the first or second longitudinal bar and pivotally coupled with the second end of an oblique bar in the plurality of oblique bars
• wherein each of the first and second longitudinal bars comprises a first bar and a second bar pivotally connected with each other, and
• wherein for at least one of the first and second longitudinal bars, the first and second bars are pivotally connected with each other by a folding/unfolding mechanism comprising:
• a first coupling piece fixed at a proximal end of the first bar, wherein the first coupling piece comprises a first hole and a first slot above the first hole, wherein the first slot has a closed bottom and an open top;
• a second coupling piece fixed at a proximal end of the second bar, wherein the second coupling piece comprises a second hole and a second slot above the second hole, wherein the second slot has a closed bottom and an open top;
• a third coupling piece comprising a third slot having a closed bottom and a closed top;
• a first rod passing through the first hole of the first coupling piece, the second hole of the second coupling piece, and the third slot of the third coupling piece, wherein
• the first and second coupling pieces are rotatable with respect to each other around the first rod, and
• the third coupling piece is movable with respect to the first rod between a first position where the first rod is at the bottom of the third slot of the third coupling piece and a second position where the first rod is at the top of the third slot of the third coupling piece;
• and
• a second rod integrally formed or coupled with a top portion of the third coupling piece, and movable together with the third coupling piece, wherein
• when the second rod is disposed in both of the first slot of the first coupling piece and the second slot of the second coupling piece, the first and second coupling pieces are restricted from rotating with respect to each other, and
• when the second rod is released from any one of the first slot of the first coupling piece and the second slot of the second coupling piece, the first and second coupling pieces are rotatable with respect to each other,
• wherein each slider comprises:
• a sleeve slidably coupled with the first or second longitudinal bar, wherein a first hole and a pillar are formed at a first side wall of the sleeve;
• a pivoting portion integrally formed or coupled with the first side wall of the sleeve, and pivotally coupled with the second end of an oblique bar in the plurality of oblique bars;
• and
• a controller disposed side by side with the pivoting portion along a longitudinal direction of the sleeve, and configured to control movement of the sleeve along the first or second longitudinal bar, wherein the controller comprises:
• a casing integrally formed or coupled with the first side wall of the sleeve and surrounding the first hole and the pillar formed at the first side wall of the sleeve;
• a lever comprising a first end portion aligned with the first hole formed at the first side wall of the sleeve, a second end portion aligned with the pillar formed at the first side wall of the sleeve, and a middle portion between the first and second portions and pivotally connected with the casing;
• a pin integrally formed or coupled with the first end portion of the level, wherein the pin has a free end toward the first hole formed at the first side wall of the sleeve;
• and
• an elastic member engaged with the pillar formed at the first side wall of the sleeve, the elastic member having a first end abutting the first side wall of the sleeve and a second end abutting the second portion of the lever, wherein when the first hole formed at the first side wall of the sleeve aligns with a hole of the first or second longitudinal bar, the elastic member pushes the free end of the pin into the first hole formed at the first side wall of the sleeve and the hole of the first or second longitudinal bar, thereby restricting movement of the sleeve with respect to the first or second longitudinal bar.