Adjustment of drop rate of elevator car with electromagnetic brake system

Patent metadata

Field	Value
Publication number	US-11897725-B2
Application number	US-202016925945-A
Country	US
Kind code	B2
Filing date	Jul 10, 2020
Priority date	Nov 24, 2014
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A braking system for an elevator includes an electromagnetic brake operably connected to an elevator car, and a control circuit operably connected to the electromagnetic brake. The control circuit includes a switching mechanism configured to selectively modify a rate of engagement of the electromagnetic brake to selectively modify a rate of deceleration of the elevator car. The switching mechanism has a first position, a second position and a third position, to selectively modify the rate of engagement.

First claim

What is claimed is:

1. A braking system for an elevator comprising:
an electromagnetic brake operably connected to an elevator car; and
a control circuit operably connected to the electromagnetic brake, the control circuit including a switching mechanism configured to selectively modify a rate of engagement of the electromagnetic brake to selectively modify a rate of deceleration of the elevator car;
wherein the switching mechanism has a first position, a second position and a third position, to selectively modify the rate of engagement;
wherein in the first position the switching mechanism closes on a first pathway to direct electrical current along the first pathway having a snubber diode to slow dissipation of current in the control circuit in an event of a loss of AC power to the control circuit; and
wherein in the second position the switching mechanism closes on a second pathway to direct directs electrical current along the second pathway arranged in parallel to the first pathway and including a snubber diode and a resistor;
wherein in the third position the switching mechanism is in an open position such that deceleration is not delayed.

2. The braking system of claim 1 , wherein the switching mechanism changes between the first position, the second position and the third position as a result of a direction of elevator car travel and a load imbalance between the elevator car and a counterweight.

3. The braking system of claim 1 , wherein in the first position an application of full torque of the brake is delayed by a first delay amount, and in the second position the application of full torque of the brake is delayed by a second delay amount different from the first delay amount.

4. The braking system of claim 3 , wherein in the third position the application of full torque of the brake is not delayed.

5. The braking system of claim 1 , wherein the switching mechanism changes between the first position, the second position and the third position at a beginning of an elevator car run.

6. The braking system of claim 1 , wherein the switching mechanism is a latching relay.

7. The braking system of claim 1 , wherein an initial current applied through the circuit is changed based on a position of the switching mechanism.

8. A method of engaging an electromagnetic brake for an elevator system comprising:
detecting one or more operational characteristics of the elevator system;
selecting a first position, a second position or a third position of a switching mechanism disposed at a brake control circuit depending on the one or more detected operational characteristics;
flowing electrical current through one or more components of the brake control circuit, depending on the position of the switching mechanism, to determine a rate of engagement of the electromagnetic brake; and
stopping a flow of electrical current through the brake control circuit, thereby causing engagement of the electromagnetic brake;
wherein in the first position the switching mechanism closes on a first pathway to direct electrical current along the first pathway having a snubber diode to slow dissipation of current in the control circuit in an event of a loss of AC power to the control circuit; and
wherein in the second position the switching mechanism closes on a second pathway to direct electrical current along the second pathway arranged in parallel to the first pathway and including a snubber diode and a resistor; and
wherein in the third position the switching mechanism is in an open position such that deceleration is not delayed.

9. The method of claim 8 , wherein in the first position an application of full torque of the brake is delayed by a first delay amount, and in the second position the application of full torque of the brake is delayed by a second delay amount different from the first delay amount.

10. The method of claim 9 , wherein in the third position the application of full torque of the brake is not delayed.

11. The method of claim 8 , wherein the switching mechanism changes between the first position, the second position and the third position at a beginning of an elevator car run.

12. An elevator system comprising:
a hoistway;
an elevator car movable along the hoistway;
a machine operably connected to the elevator car to urge movement of the elevator car along the hoistway;
an electromagnetic brake operably connected to an elevator car; and
a control circuit operably connected to the electromagnetic brake, the control circuit including a switching mechanism configured to selectively modify a rate of engagement of the electromagnetic brake to selectively modify a rate of deceleration of the elevator car;
wherein the switching mechanism has a first position, a second position and a third position, to selectively modify the rate of engagement;
wherein in the first position the switching mechanism closes on a first pathway to direct electrical current along the first pathway having a snubber diode to slow dissipation of current in the control circuit in an event of a loss of AC power to the control circuit; and
wherein in the second position the switching mechanism closes on a second pathway to direct electrical current along the second pathway arranged in parallel to the first pathway and including a snubber diode and a resistor; and
wherein in the third position the switching mechanism is in an open position such that deceleration is not delayed.

13. The elevator system of claim 12 , wherein in the first position an application of full torque of the brake is delayed by a first delay amount, and in the second position the application of full torque of the brake is delayed by a second delay amount different from the first delay amount.

14. The elevator system of claim 13 , wherein in the third position the application of full torque of the brake is not delayed.

Assignees

• Otis Elevator Co

Inventors

• Millett Steven M
• Agirman Ismail
• Lotfi Amir

Classifications

• B66B1/32 Primary

  effective on braking devices {, e.g. acting on electrically controlled brakes (brake control H02P, lift brakes per se B66B5/02)} · CPC title

• B66B5/02

  responsive to abnormal operating conditions · CPC title

• B66B11/0476

  with friction gear, e.g. belt linking motor to sheave · CPC title

• B66B1/26

  mechanical · CPC title