Joint structure of universal linkage used in lighting system, has biasing device having central cylinder to circulate cable duct so that joint cases are rotated and passed through cable in biasing position by linkage portions rotation

摘要

The structure has primary and secondary joint cases connected with linkage portions (5,6). A biasing device generates biasing force from assembly position into biasing position. A fixing element in primary joint case releasably locks biasing device in spring force-loaded biasing position. The biasing device has central cylinder to circulate cable duct such that joint cases are rotated together and passed through cable in locked biasing position by rotation of linkage portions. A coupling device of secondary joint case is coupled with fixing element using biasing force.