12 to slide toward each other along the rails 224 when an external force separating the sliders is released the first resisting member 15 may be an elastic resisting member such as an expansion spring a compression spring or an elastic band in this embodiment the first resisting member 15 includes two parallel compression springs in which two ends of each compression spring are respectively retained on the sliders 12 the first shaft 42 is configured to be pivotably coupled to one end portion 132 of the support board 13 to the housing 20 at one end 244 of the second mounting portion 242 the support board 13 can be rotated relative to the housing 20 from the closed position shown in fig2 or retracted from the open position shown in fig4 the support board 13 in this embodiment is complementary in shape to the second mounting portion 242 of the housing 20 the support board 13 is accommodated in the second mounting portion 242 when the support mechanism is in a closed state a second resisting member 16 is coupled between the support board 13 and the housing 20 the second resisting member 16 exerts a force on the support board 13 and the housing 20 causing the support board 13 to rotate about the first shaft 42 relative to the housing 20 the second resisiting member 16 may be an elastic resisting member such as a compression spring in this embodiment the.