Elevator Brake Condition Testing

• US 20100154527A1
• Filed: 02/14/2006
• Published: 06/24/2010
• Est. Priority Date: 02/14/2006
• Status: Abandoned Application

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Illan, Juan Antonio
• Application Number:
  US12/223,838
• Publication Number:
  US 20100154527A1
• Time in Patent Office: Days
• US Class Current: 73/121
• CPC Class Codes: B66B 5/0037 Performance analysers
• CPC Class Codes: B66B 5/0093 Testing of safety devices

Abstract

A brake (42) is tested in an elevator system (10) including a car (12) and a counterweight (14) connected to the car (12) by a rope (16). The car (12) is positioned at a reference position in the hoistway (HW) adjacent to a hoistway limit switch (23), and the brake (42) is engaged to hold the car (12) at the reference position. The rotating member (46) is then driven to provide a testing force on the brake (42) that simulates a load in the elevator car (12) of at least a maximum rated load for the car (12). The brake test is terminated if the hoistway limit switch (23) is actuated.

Claims

1. A method for testing a brake in an elevator system including an elevator hoistway having a car and a counterweight connected to the car by a cable, the cable actuated by a rotating member driven by a motor, the method comprising:

positioning the elevator car at a reference position in the hoistway adjacent to a hoistway limit switch;

engaging the brake to hold the car at the reference position;

driving the rotating member to provide a testing force on the brake that simulates a load in the car of at least a maximum rated load for the car; and

terminating the brake testing if the car moves to actuate the hoistway limit switch.

2. The method of claim 1, wherein the positioning step comprises positioning the car with no load at the reference position.

3. The method of claim 1, wherein the engaging step comprises engaging the brake to prevent movement of the rotating member.

4. The method of claim 1, wherein the driving step comprises driving the rotating member such that a first force on the brake provided by relative weights of the counterweight and car and a second force provided by the motor equals the testing force.

5. The method of claim 1, wherein the testing force simulates a load of at least 125% of the maximum rated load for the car.

6. The method of claim 1, and further comprising:

sensing motion of the car relative to the reference position.

7. A system comprising:

an elevator including an elevator hoistway having an elevator car and a counterweight connected to the elevator car by a rope;

a machine including a motor, a rotating member driven by the motor for actuating the rope, and a brake for preventing the rotating member from rotating;

a controller operable to test the brake by driving the rotating member with the brake engaged to provide a testing torque on the brake that simulates a load in the elevator car of at least a maximum rated load for the elevator car, and

a hoistway limit switch that provides a signal to the controller to terminate the test if the elevator car moves to actuate the hoistway limit switch while the rotating member is being driven.

8. The system of claim 7, wherein the system further comprises an encoder for sensing motion of the elevator car when the testing torque is provided by driving the rotating member.

9. The system of claim 8, wherein the encoder provides a signal to the controller to terminate the test if motion of the elevator car is sensed.

10. The system of claim 7, wherein the testing torque simulates a load of at least 125% of the maximum rated load for the elevator car.

11. The system of claim 7, wherein the controller tests the brake when the elevator car is without a load.

12. The system of claim 7, wherein the elevator car is positioned at a top landing in the elevator hoistway to test the brake.

13. The system of claim 7, wherein relative weights of the elevator car and the counterweight provide at least a portion of the testing torque.

14. A method for testing a brake in an elevator system, the method comprising:

engaging the brake to hold the elevator in position, wherein relative weights of an elevator car and a counterweight in the elevator system produce a first torque on the brake when the brake is engaged;

driving an elevator motor when the brake is engaged to produce a second torque on the brake, wherein the first torque and the second torque simulate a load in the elevator car of at least a maximum rated load for the elevator car; and

terminating the brake testing if the elevator car actuates a hoistway limit switch.

15. The method of claim 14, wherein engaging the brake to hold the elevator in position comprises preventing relative movement between the elevator car and the counterweight.

16. The method of claim 14, wherein the first torque and the second torque simulate a load of at least 125% of the maximum rated load for the car.

17. The method of claim 14, wherein the brake is tested with no load in the elevator car.

18. The method of claim 14, wherein the sensing step comprises processing signals from an encoder related to movement of the elevator car.

19. The method of claim 14, wherein the elevator car is positioned at a top landing in an elevator hoistway to test the brake.

20. The method of claim 14, and further comprising:

sensing movement of the elevator car when driving the elevator motor with the brake engaged.