Mechanical overspeed safety device
AssigneeOtis Elevator Company
InventorsWilliam Sheridan, Anthony Cooney
Life of this patent
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Abstract
An overspeed governor comprises a pair of wedge brakes for selectively acting against a brake surface attached to the rotational shaft of an elevator drive. A maintaining apparatus is provided to maintain the wedge brakes in a normal position, out of engagement with the brake surface. A centrifugal actuating apparatus is also provided, attached to the rotational shaft of the elevator drive. If the rotational velocity of the elevator drive exceeds a predetermined limit, the centrifugal actuating apparatus displaces the maintaining apparatus, thereby allowing one of the wedge brakes to engage the brake surface.
Claims13
A bidirectional overspeed governor for an elevator having a rope supported elevator car in a hoistway and a drive means having a rotational shaft and a brake surface fixed to said shaft, for driving said elevator car within said hoistway, said governor comprising:
- a pair of wedge brakes, for selectively acting against the brake surface in either direction of rotation;
- mechanical maintaining means for maintaining said wedge brakes in a normal position, out of engagement with the brake surface;
- and
- centrifugal actuating means for displacing said maintaining means from said normal position if the rotational velocity of the drive means exceeds a predetermined limit in either direction of rotation, thereby allowing one of said wedge brakes to engage the brake surface.
A method for stopping an ascending or descending elevator, having a drive means with a rotational shaft and a brake surface attached to said shaft, in an overspeed condition comprising the steps of:
- providing a pair of wedge brakes for selectively acting against the brake surface as the elevator ascends or descends;
- providing mechanical maintaining means for maintaining said wedge brakes in a normal position, out of engagement with the brake surface;
- and
- providing centrifugal actuating means for displacing said maintaining means from said normal position if the rotational velocity of the drive means exceeds a predetermined limit as the elevator ascends or descends, thereby allowing one of said wedge brakes to engage the brake surface.
Dependencies are inferred from the claim text.