US Patent 7414836 Auto-extending replicator

An auto-extending replicator includes a replicator body, a forcing mechanism, an extended unit and a control mechanism. The extended unit includes an extended body and a blocking member. The forcing mechanism connected between the replicator body and the extended body exerts a force on the extended body along a direction of extending. The blocking member connected with the extended body has a stepped structure. A control mechanism second end blocks the blocking member from extending out. When a control mechanism first end is displaced, a contact position between the blocking member and the control mechanism second end is changed so that the extended body together with the blocking member move extendedly along the direction of extending.