The utility model relates to an aggregate unit of mechanism belongs to the technical field of electrical switching equipment. The utility model discloses an aggregate unit of mechanism includes: install and keeping apart main epaxial isolation gear, install the epaxial ground connection gear the ground connection owner, and with keep apart gear or ground connection gear drive close separating brake linkage unit, keep apart and leave the idle running between gear and the ground connection gear, circuit breaker energy storage axle of isolating switch component and earthing switch subassembly sharing has been realized, with this aggregate unit of mechanism be used for the cubical switchboard can for the cubical switchboard provide perfect interlocking function and save the cabinet in the inner space, the performance of isolation with ground connection has been improved, realized that power supply system is reliable, supply power high -efficiently.