Movable extending device for unit flow long mould production line

The invention provides a movable extending device for a unit flow long mould production line. The device comprises a movable extending block, wherein the movable extending block is arranged in a switch tie model groove of a switch tie model; the front and back sides of the movable extending block are attached to the inside surface of the switch tie model groove; the bottom of the movable extending block is attached to the bottom of the switch tie model groove; two vertical hanging plate grooves with T-shaped sections are formed on the left side and right side of the movable extending block; the upper ends of the vertical hanging plate grooves are opened to the upper surface of the movable extending block; and a bottom plate for the hanging plate grooves is arranged under the vertical hanging plate grooves. The device overcomes the limit of the length of a model shell to the cropping length of a steel wire, so that the cropping length of pre-stress steel wire can be determined according to the length of the sw