Moving a heavy overload with an elevator

An elevator installation comprising:

• a car;
• a counterweight interconnected with the car by at least one suspension rope engaging a traction sheave driven by a motor;
• an elevator controller controlling the motor and being switchable between being enabled for an overload trip and not being enabled for an overload trip;
• a compensation rope tensioning device for enhancing traction between the at least one suspension rope and the traction sheave independently of a weight of the counterweight for temporary transportation of an overload, the compensation rope tensioning device having a compensation rope pulley box attached to an actuator through a damper or a spring, the actuator being mounted to a pit floor of a hoistway in which the car and the counterweight are positioned, the compensation rope pulley box engaging at least one compensation rope suspended between the car and the counterweight;
• wherein during a normal operation of the elevator installation the actuator and the damper or the spring impose a downward force on the compensation rope pulley box, the downward force being transmitted through the at least one compensation rope, the car and the counterweight to act as tension within the at least suspension rope;
• and
• when the elevator controller is not enabled for an overload trip, the elevator controller maintains the car stationary at a landing upon detection of an overload in the car and when the elevator controller is enabled for an overload trip, the elevator installation is used for a temporary transportation of a detected overload in the car, and the actuator draws the damper or the spring and the compensation rope pulley box downwards imparting an increased downward force on the compensation rope pulley box resulting in an increased tension within the at least one suspension rope.

A method for temporary transportation of an overload within an elevator installation, the elevator installation having a car and a counterweight interconnected by at least one suspension rope engaging a traction sheave driven by a motor, the method comprising the steps of:

• enhancing traction between the at least one suspension rope and the traction sheave independently of a weight of the counterweight by providing a compensation rope tensioning device having a compensation rope pulley box attached to an actuator through a damper or a spring, the actuator being mounted to a pit floor of a hoistway in which the car and the counterweight are positioned, the compensation rope pulley box engaging at least one compensation rope suspended between the car and the counterweight;
• monitoring a load within the car when the car is stopped at a landing of the hoistway to detect an overload;
• when the overload is not detected, commencing a normal operation of the elevator installation wherein the actuator and the damper or the spring impose a downward force on the compensation rope pulley box, the downward force being transmitted through the at least one compensation rope, the car and the counterweight to act as tension within the at least suspension rope;
• when the overload is detected and the elevator installation is not enabled for an overload trip, sounding an overload alarm and preventing the car from moving;
• and
• when the overload is detected, determining whether an elevator controller controlling the motor is enabled for an overload trip and when the elevator controller is enabled for an overload trip, further enhancing traction by operating the actuator to draw the damper or the spring and the compensation rope pulley box downwards imparting an increased downward force on the compensation rope pulley box resulting in an increased tension within the at least one suspension rope.