Opening-and-closing mechanism and latching mechanism

1. An opening-and-closing mechanism comprising:

a first supporting member and a second supporting member disposed so as to be capable of relative rotation around a rotary axis;

a plurality of protruding portions provided on the first supporting member; and

a plurality of depressed portions provided on the second supporting member and engaged with the plurality of protruding portions,

wherein at least some of the plurality of depressed portions have different lengths in a circumferential direction centered at the rotary axis and different positions in a radial direction than others of the plurality of depressed portions;

wherein, when the first supporting member and the second supporting member are in a plurality of predetermined relative alignments, a predetermined amount of the plurality of protruding portions and the same amount of the plurality of depressed portions are engaged;

wherein forces required for disengaging the protruding portions and the depressed portions by rotating at least one of the first supporting member and second supporting member differ in a first rotation direction and a second rotation direction; and

wherein the positions and the lengths in the circumferential direction of the depressed portions are set so that the number of protruding portions and depressed portions that are simultaneously disengaged differs depending on the relative rotating direction.

2. The opening-and-closing mechanism according to claim 1 ,

wherein the depressed portions are arc-shaped, extending in the circumferential direction centered at the rotary axis.

3. The opening-and-closing mechanism according to claim 1 ,

wherein the depressed portions extend in the circumferential direction centered at the rotary axis, and the widths in the radial direction differ at both ends in the circumferential direction.

4. The opening-and-closing mechanism according to claim 1 ,

wherein the depths of the depressed portions differ at both ends in the circumferential direction centered at the rotary axis.

5. The opening-and-closing mechanism according to claim 1 , further comprising:

a connecting member for connecting the first supporting member and the second supporting member in a rotatable manner around the rotary axis,

wherein a pushing force acting upon a contact section of the first supporting member and the second supporting member is controlled by the connecting member.

6. The opening-and-closing mechanism according to claim 1 , further comprising:

a sliding member for controlling a coefficient of friction between the first supporting member and the second supporting member.

7. The opening-and-closing mechanism according to claim 1 , further comprising:

a stopper portion for limiting the range of relative alignment adopted by the first supporting member and the second supporting member, the stopper portion being provided on at least one of the first supporting member and the second supporting member.

8. A latching mechanism which is interposed between a first member and a second member that are moved relatively and which latches the relative movement of the first member and the second member, the latching mechanism comprising:

a plurality of protruding portions provided on the first member; and

a plurality of depressed portions provided on the second member and engaged with the protruding portions,

wherein at least some of the plurality of depressed portions have different lengths in the relative movement direction and positions in a direction intersecting the relative movement direction than others of the plurality of depressed portions;

wherein a force required for disengaging the protruding portions and the depressed portions differs depending on the relative movement direction;

wherein the positions and lengths of the depressed portions are set such that the number of protruding portions and depressed portions simultaneously disengaged differs depending on the relative movement direction.

9. The latching mechanism according to claim 8 , wherein a plurality of sets of depressed portions comprising a plurality of depressed portions that are simultaneously engaged with the plurality of protruding portions are provided in the relative movement direction of the first member and the second member, with spaces provided between the sets.

10. The latching mechanism according to claim 8 ,

wherein the depressed portions extend in the relative movement direction of the first member and the second member.

11. The latching mechanism according to claim 8 ,

wherein the depressed portions extend in the relative movement direction of the first member and the second member, and

wherein the widths of the depressed portion in a direction intersecting with the relative movement direction differ at both ends in the relative movement direction.

12. The latching mechanism according to claim 8 ,

wherein the depressed portions extend in the relative movement direction of the first member and the second member, and

wherein the depths of the depressed portions differ at both ends in the relative movement direction.

13. The latching mechanism according to claim 8 , wherein each of the protruding portions includes a spherical body having a spherical surface that engages with one of the depressed portions and a pushing member that pushes the spherical body toward the second member.