Patent ID: 7717237

Claim:
A passenger or cargo elevator or lift based on chains, counterweights and servomotors of the type having a cabin that is transported vertically; said elevator comprising: at least one traction system comprising a set of traction chains; a set of traction sprockets mounted on a first shaft that rotates between two bearings and which is connected by a flexible coupling to at least one planetary speed reducer to which at least one servomotor with a brake is connected; a set of upper tension sprockets; at least one counterweight equivalent to a weight of said cabin plus approximately 50% of the maximum load to be transported; a second set of descending chains connecting the at least one counterweight to a lower part of said cabin; a second set of lower tension sprockets firmly mounted on a second shaft that revolves between two bearings that are each supported by a structure anchored to an elevator pit; a third set of lower tension sprockets that are mounted on a third shaft that revolves between two bearings that are firmly anchored to a structure placed in the elevator pit; a power and control system comprising a programmable logic controller (PLC) that receives command calls from call buttons both on building floors, where the elevator operates and a call button in the elevator cabin; said power and control system adapted to send commands to a motion controller for said at least one servomotor which, based on predetermined parameters, orders at least one servo-amplifier to feed electric power to said at least one servomotor and associated brake in order that it performs a predetermined operation; said elevator further including an encoder mounted on the first shaft of its corresponding servomotor; the encoder configured to provide control pulses and feedback to said servo-amplifier and said PLC about operations performed by the at least one traction system.