Elevator braking device, powerhead and methods

A brake system for use with a rotating cable drum around which a cable operably coupled to an elevator car of an elevator is wound, comprising:

• a brake rotor operably attachable to the cable drum to rotate with cable drum;
• a brake caliper assembly including:
• a brake member for selectively engaging with the brake rotor;
• a brake member actuation lever having a first position in which the brake rotor is free to move relative to the brake member and a second position in which the brake member is biased into engagement with the brake rotor and the brake rotor is prevented from moving relative to the brake member under the weight of the elevator car and any rated load;
• a biasing member acting on the brake member actuation lever biasing the brake member actuation lever from the first position towards the second position;
• a speed sensing arrangement for sensing a rotational speed of the cable drum;
• a latch arrangement having a first orientation maintaining the brake member actuation lever in the first position and a second orientation releasing the brake member actuation lever such that the brake member actuation lever can transition from the first position to the second position, the latch arrangement transitioning from the first orientation to the second orientation when the speed sensing arrangement senses that the rotational speed of the cable drum is at least a predetermined rotational speed;
• an actuator coupled to the latch arrangement to drive the latch arrangement from the first orientation to the second orientation when the predetermined rotational speed is sensed;
• and
• a controller connected to the actuator and configured to control actuation of the actuator and to activate the actuator when the predetermined rotational speed is sensed, the overspeed controller including a backup battery for powering the actuator in the event of a main power failure.

A powerhead for an elevator comprising:

• a motor;
• a cable drum operably driven by the motor;
• a brake system comprising:
• a brake rotor operably attachable to the cable drum to rotate with cable drum;
• a brake caliper assembly including:
• a brake member for selectively engaging with the brake rotor;
• a brake member actuation lever having a first position in which the brake rotor is free to move relative to the brake member and a second position in which the brake member is biased into engagement with the brake rotor and the brake rotor is prevented from moving relative to the brake member under the weight of the elevator car and any rated load;
• a biasing member acting on the brake member actuation lever biasing the brake member actuation lever from the first position towards the second position;
• a speed sensing arrangement for sensing a rotational speed of the cable drum;
• a latch arrangement having a first orientation maintaining the brake member actuation lever in the first position and a second orientation releasing the brake member actuation lever such that the brake member actuation lever can transition from the first position to the second position, the latch arrangement transitioning from the first orientation to the second orientation when the speed sensing arrangement senses that the rotational speed of the cable drum is at least a predetermined rotational speed;
• the brake system being operably attached to the cable drum such that when the brake member actuation lever is in the first position the brake rotor is free to move relative to the brake member and when the brake member actuation lever is in the second position the brake member is biased into engagement with the brake rotor and the brake rotor is prevented from moving relative to the brake member inhibiting rotational motion of the cable drum;
• an actuator coupled to the latch arrangement to drive the latch arrangement from the first orientation to the second orientation when the predetermined rotational speed is sensed;
• and
• an overspeed controller connected to the actuator and configured to control actuation of the actuator, the overspeed controller including a backup battery for powering the actuator in the event of a main power failure.

A powerhead for an elevator comprising:

• a motor;
• a cable drum operably driven by the motor;
• a brake system comprising:
• a brake rotor operably attachable to the cable drum to rotate with cable drum;
• a brake caliper assembly including:
• a brake member for selectively engaging with the brake rotor;
• a brake member actuation lever having a first position in which the brake rotor is free to move relative to the brake member and a second position in which the brake member is biased into engagement with the brake rotor and the brake rotor is prevented from moving relative to the brake member under the weight of the elevator car and any rated load;
• a biasing member acting on the brake member actuation lever biasing the brake member actuation lever from the first position towards the second position;
• a speed sensing arrangement for sensing a rotational speed of the cable drum;
• a latch arrangement having a first orientation maintaining the brake member actuation lever in the first position and a second orientation releasing the brake member actuation lever such that the brake member actuation lever can transition from the first position to the second position, the latch arrangement transitioning from the first orientation to the second orientation when the speed sensing arrangement senses that the rotational speed of the cable drum is at least a predetermined rotational speed;
• the brake system being operably attached to the cable drum such that when the brake member actuation lever is in the first position the brake rotor is free to move relative to the brake member and when the brake member actuation lever is in the second position the brake member is biased into engagement with the brake rotor and the brake rotor is prevented from moving relative to the brake member inhibiting rotational motion of the cable drum;
• an actuator coupled to the latch arrangement to drive the latch arrangement from the first orientation to the second orientation when the predetermined rotational speed is sensed;
• and
• a controller connected to the actuator and configured to control actuation of the actuator, the controller including a backup battery for powering the actuator in the event of a main power failure, the controller being configured to control the motor that drives the cable drum.

A method of operating a brake system for an elevator comprising:

• sensing a rotational speed of a cable drum of a powerhead of the elevator;
• actuating a brake member to engage a rotor when the rotational speed of the cable drum is at least a predetermined rotational speed to engage a brake rotor operably attached to the cable drum, the brake rotor rotating with the cable drum, engagement of the brake member with the rotor reducing or stopping rotational motion of the rotor and cable drum;
• transitioning a brake member actuation lever from a first position in which the brake rotor is free to move relative to the brake member and a second position in which the brake member is biased into engagement with the brake rotor and the brake rotor is prevented from moving relative to the brake member under the weight of the elevator car and any rated load when the predetermined rotational speed is sensed;
• biasing the brake member actuation lever from the first position towards the second position;
• transitioning a latch arrangement from a first orientation maintaining the brake member actuation lever in the first position to a second orientation releasing the brake member actuation lever such that the brake member actuation lever can transition from the first position to the second position, the latch arrangement transitioning from the first orientation to the second orientation when the speed sensing arrangement senses that the rotational speed of the cable drum is at least a predetermined rotational speed;
• wherein transitioning the latch arrangement includes actuating an electrically powered actuator, wherein actuating an electrically powered actuator occurs upon a failure of main power and the electrically powered actuator is powered by a backup battery.