IMPROVEMENTS TO A PASSENGER OR FREIGHT LIFT BASED ON THE USE OF CHAINS, COUNTERWEIGHTS AND SERVOMOTORS

摘要

A passenger or cargo elevator based on the use of chains, counterweights and servomotors that represents an improved version over traditional elevators for cargo or for passengers. The improvements consist in the substitution of traction cables by traction chains, but in a closed loop wherein the chains serve both to pull the elevator cabin up and to also pull down the counterweight. Through this means we obtain a better performance in the latter and consequently we can have counterweights that not only exceed the cabin's weight but we can also consider additional counterweights for up to 50% of the load one plans to lift without having the problem of sudden pulls on the chains due to inertia during the braking process. The traction motor equipment used are planetary type speed reducers which have greater efficiency and precision and are coupled to servomotors that allow for complete accuracy in the programming of the movements that may be required for the elevator. The control system is based on a programmable logic controller (PLC) and on the servomotor controller which, together with the servomotor encoders, provide the precise positioning as well as the speed and torque pre-programmed in an optimal manner, so as to have the best possible system performance and obtain the compensations that might at one or another time be required.