Patent ID: 7331567

Claim:
A coupling device for two connecting poles comprising: a lower fixing sleeve sleeved on the upper portion of the lower connecting pole, having a through opening communicating with the outer surface and the inner surface of the lower fixing sleeve, two fixed plates extend outwards from the edge of the said opening; an upper fixing sleeve sleeved on the lower portion of the upper connecting pole, having a through gap communicating with the outer surface and the inner surface of the upper fixing sleeve, two fixing plates extend outwards from the edge of the said gap, the said fixing plates of the upper fixing sleeve are disposed within the opening of the lower fixing sleeve; the fixing plates including a releasing portion in the top portion and a locking portion beneath the releasing portion, a horizontal distance from the outer side surface of the locking portion to the edge of the gap is bigger than a horizontal distance from the outer side surface of the releasing portion to the edge of the gap; a controlling member rotatably connected between the fixed plates of the lower fixing sleeve, including a central portion and two side portions at both sides of the central portion, among the two side portions and the central portion there forms a space for receiving a portion of the two fixing plates, the inner side surfaces of the two side portions keep in touch with the outer side surfaces of the two releasing portions; wherein the upper fixing sleeve includes at least one rack grafted to the outer side surfaces of the fixing plates; and the perimeters of the two side portions of the controlling member are of gears that match the at least one rack beside the fixing plates.