Joint mechanism

A joint mechanism comprising:

• a pivot ball having a curved outer surface;
• a pivot shaft being non-rotatable relative to the pivot ball;
• a rotary arm comprising:
• a spherical housing defining a cavity for rotatably receiving the pivot ball;
• a restricting hole defined in the spherical housing at an open end of the cavity to receive the pivot shaft, wherein the restricting hole has a radius to allow an angular movement of the pivot shaft and limit this angular movement when the pivot shaft comes into contact with an edge of the restricting hole;
• at least one bearing holder defined within an inner surface of the housing cavity and comprising a plurality of fixing ribs extending from the inner surface;
• an extension arm extending from the spherical housing;
• two latching grooves defined in an outer surface of the spherical housing adjacent the extension arm;
• and
• at least one bearing being fixed within the housing cavity, the at least one bearing including a concave inner surface, the concave inner surface engaging with the curved outer surface of the pivot ball, the at least one bearing defining a plurality of concave portions for engaging with the fixing ribs of the at least one bearing holder of the rotary arm;
• and
• a sleeve being substantially a flexible and hollow cylinder with two openings at opposite ends thereof, wherein the sleeve comprises a through hole passing through a cylindrical surface of the sleeve, two latching portions formed on opposite sides of the through hole, and a slit communicating the through hole and one of the openings of the sleeve, when an external force is applied to the slit, the extension arm is insertable into the through hole of the sleeve, and the two latching portions being engaged in the corresponding latching grooves of the spherical housing;
• wherein the pivot ball comprises a limiting block protruding out from an end of the pivot ball, the spherical housing comprises two stopper portions formed in the inner surface of the housing cavity, and a range of rotation of the rotary arm relative to the pivot ball is determined when the limiting block comes into contact with the stopper portions.