Interlock device
How does an interlock device function?
The interlock device prevents lift cages from sinking down when loading heavy cargo (prompted by the extension of the hoist ropes or compression of the hydraulic oil) in the case of lifts with heavy load capacity.
This prevents differences of level from arising.
The electromechanical or electro hydraulic interlock stops the lift from moving when loading or unloading. The lift initially goes through the stop, deploys the interlock bolts and subsequently sinks down as intended to the supporting brackets in the hoistway.
When leaving the holding position the cab is slightly lifted and the the interlock bolts are retrieved.