A method for limiting the speed of a hoist mounted to a mobile well service rig involves determining a safe speed limit that ensures the hoist's capable stopping time is less than the maximum allowed time for stopping. In some examples, the maximum allowed time for stopping is based on the wellstring's modulus of elasticity and independent of the hoist's braking characteristics. The capable stopping time, however, is independent of the wellstring's modulus of elasticity and dependent on the hoist's braking characteristics.

The invention relates to a safety brake for an elevator, a centrifugal regulator and a way of using this in a safety brake. According to the invention, the safety brake comprises a centrifugal regulator (3), a shaft (4), which rotates due to a coupling (5) to the elevator, a first (6) and a second (8) brake part movable against each other with friction surfaces (10, 11), the first brake part being rotatable with the shaft, a spring assembly (30) with which the brake parts are spring-biased with a pressure force, on release the centrifugal regulator is provided to couple the shaft (4) to the first brake part (6) to force rotation on it. The safety brake is self-regulating by comprising the pressure-relieving arrangement provided, due to the rotation of the shaft (4), to relieve the spring biasing by pressing the first brake part (6) towards the spring assembly's (30) spring action and thus from the other brake part (8), until a balanced position is obtained whereby both brake parts (6, 8) frictionally slide against each other.

The invention relates to a safety brake for an elevator, a centrifugal regulator and a way of using this in a safety brake. According to the invention, the safety brake comprises a centrifugal regulator (3), a shaft (4), which rotates due to a coupling (5) to the elevator, a first (6) and a second (8) brake part movable against each other with friction surfaces (10, 11), the first brake part being rotatable with the shaft, a spring assembly (30) with which the brake parts are spring-biased with a pressure force, on release the centrifugal regulator is provided to couple the shaft (4) to the first brake part (6) to force rotation on it. The safety brake is self-regulating by comprising the pressure-relieving arrangement provided, due to the rotation of the shaft (4), to relieve the spring biasing by pressing the first brake part (6) towards the spring assembly's (30) spring action and thus from the other brake part (8), until a balanced position is obtained whereby both brake parts (6, 8) frictionally slide against each other.

An elevator brake (20) has at least one brake disc (30) comprising a metal matrix composite, the metal matrix composite including at least an aluminum alloy and silicon carbide. The metal matrix composite in particular comprises Aluminum 6061, silicon carbide and redmud.

An elevator brake (20) has at least one brake disc (30) comprising a metal matrix composite, the metal matrix composite including at least an aluminum alloy and silicon carbide. The metal matrix composite in particular comprises Aluminum 6061, silicon carbide and redmud.

A hoist system includes a hook; a cable connected to the hook; a motor configured to move the hook and the cable; an overload protection device (OLPD) configured to limit loads imparted on one or more of the hook, the cable, and the motor. The hoist system further includes an emergency brake system configured to stop movement of at least the cable, where the emergency brake system is configured to operate in response to a manual control or automatically in response to a controller.

An overspeed brake system for use in an elevator powerhead is provided. A brake rotor is attachable to a cable drum to rotate with a cable drum. A brake member selectively engages the brake rotor upon transition of an actuation lever from a first position to a second position. A biasing member acts on the actuation lever to bias the actuation lever from the first position towards the second position. A latch arrangement has a first orientation maintaining the actuation lever in the first position and a second orientation releasing the actuation lever for transitioning from the first position to the second position. The latch arrangement transitions from the first orientation to the second orientation when a speed sensing arrangement senses that the rotational speed of the cable drum is at least a predetermined rotational speed.

An elevator system (10) is comprised of a car (22), and a shaft (46) operatively connected to the car and configured to rotate for movement of the car through the elevator system. A brake assembly (44) is comprised of a disk (56) connected to and configured to rotate along with the shaft. Movable plates (60, 62) are placed on respective opposite sides of the disk and configured to move axially toward and away from the disk. Electromagnets are configured to respectively move the movable plates away from the disk. Elastic elements (64, 66) are configured to respectively move the movable plates toward the disk. The disk is free to move axially, and is designed to stop the movement of the car by stopping the rotation of the shaft when the rotation of the disk is stopped by friction from contact of the movable plates with the disk when the elastic elements move the movable plates toward the disk.

Brake release sensors for an elevator can be replaced by an arrangement wherein the brake release is determined from the force caused by the brake. This is achieved by providing measuring device for measuring the weight of an elevator car between the brake and the motor body so that the weight of the elevator car is measured only when the brake is on.

A braking system for a motor housing is provided. In one example, braking system comprises a double disk brake configuration arranged in a motor housing. A working position of the double disk brake is configured to automatically adjust based on a condition of a friction pad of a friction disk.