Elevator – industrial lift truck – or stationary lift for vehicle – With barrier for regulating access to load support – Including slideably mounted barrier on load support
Reexamination Certificate
2000-03-10
2001-04-24
Olszewski, Robert P. (Department: 3652)
Elevator, industrial lift truck, or stationary lift for vehicle
With barrier for regulating access to load support
Including slideably mounted barrier on load support
C187S319000, C049S120000
Reexamination Certificate
active
06220396
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to door interlock systems used in elevators. In particular, the invention concerns a door restrictor apparatus for an elevator door apparatus that prevents the elevator doors from opening when the elevator cab is between landings and not aligned with the hatchway doors of the system.
2. Description of the Related Art
In conventional elevators, an elevator car typically includes a motor to open and close the car door or doors. When the car is stopped at a landing, a clutch mechanism on the car door engages rollers on the hatchway door or doors so that the hatchway door opens and closes in unison with the car door.
One of the safety devices commonly provided on modern passenger elevators is a mechanism to prevent the car doors from opening when the car is not within a certain distance of the landing. This feature is desirable in the case of a car that has become stuck between floors, because it prevents passengers from prying open the doors in an attempt to exit the car, which could result in injury. Such devices also prevent the door(s) from opening in the event that the door motor, due to a malfunction, were to attempt to open the doors when the car is not at a landing.
U.S. Pat. No. 4,313,525, to McDonald, discloses a car door safety interlock system. In that system, a power operated sliding door of an elevator car is provided with a mechanical safety interlock which permits the car door to be moved more than a critical distance from its closed position only when the car is in a landing zone. A pivoted interlock hook on the car door has a normal position in which it engages an interlock lug on the car frame when the door moves the critical distance from closed position. A movable element on the car door is driven to move the hook to a clearance position relative to the interlock lug. Drive of the movable element occurs when it contacts an inter-engaging member on the hatch door as the car door first starts to move from closed position in a landing zone.
It is an object of the present invention to provide an improved apparatus for preventing an elevator car door from opening when the car is not within a predetermined distance of a landing.
SUMMARY OF THE INVENTION
The present invention provides a novel design of a door restrictor apparatus for locking and preventing a sliding door on an elevator car from unauthorized opening when the car is not at a landing area. In accordance with the present invention, a locking lug is mounted on the elevator car. An actuating mechanism having an actuating surface that moves toward and away from a surface on the car door is disposed on the surface of the car door. A pivotable hook, having an axis of rotation perpendicular to the direction of the door movement is also mounted on the door. The hook has a beak end that alternatively passes by or engages the locking lug depending upon the rotational position of the hook. A crank and push rod assembly disposed on the door is connected to the actuating mechanism and to the hook and couples the movement and position of the actuating surface to the rotation and position of the hook and vice-versa. The restrictor apparatus also includes a means for biasing the restrictor to urge the actuating surface to move away from the door and to urge the hook to rotate in a first direction (e.g. clockwise). In a preferred embodiment, the means for biasing is at least one leaf spring mounted to the actuating mechanism.
The restrictor apparatus of the invention has three positions: (i) a closed position; (ii) an unlocked position; and (iii) a locked position. In the closed position, the elevator car doors are closed, the hook is oriented at a first position and the actuating surface is oriented at a corresponding first position relative to the door surface. When the elevator doors are closed the beak end of the hook engages a fixed member mounted on the car and the hook is thereby rotated to the first position and the restrictor apparatus is thus placed in the closed position. In a preferred embodiment, the fixed member is a hook roller mounted on the car and having an axis of rotation that is parallel to the axis of rotation of the hook.
As the sliding door(s) begins to open, the beak end moves off the fixed member. Because of the bias in the apparatus, the hook begins to rotate and the actuating surface begins to move away from the surface of the door. At this point, the restrictor apparatus will move into the unlocked or locked position depending on whether the car is at a landing or is between landings. In the unlocked position, when the door opens while the car is at a landing, the hook will rotate and stop at a second position where the beak will pass by the lug as the door opens and wherein the actuating surface is at a corresponding second position. In the locked position, when the door opens while the car is not at a landing, the hook will rotate and stop at a third position where the beak will engage the lug and wherein the actuating surface is at a corresponding third position.
The crank and push rod assembly has a crank body that rotates about an axis. A first arm extends from the crank body in a direction generally perpendicular to the axis of rotation. A second arm extends from the crank body also in a direction generally perpendicular to the axis of rotation. A slide bushing is seated on the first arm and has a cylindrical bore. The slide bushing is capable of rotating about and sliding along the first arm. The slide bushing also has an elongated slot with a length dimension parallel to its cylindrical axis and has a width dimension perpendicular to the length dimension that is shorter then the length dimension.
In one embodiment, the present invention is employed in an elevator system having an elevator shaft, a plurality of landings, and hatchway doors at each landing. Each hatchway door has one or more hatchway rollers for engaging a clutch that is mounted on the outside of the car door. The clutch and hatchway rollers, when engaged, cause the hatchway door to open in unison with the car door. As discussed below, the hatchway door rollers also can be used to engage the actuating surface of the actuating mechanism.
In operation of this embodiment, the present invention functions as follows. When the car door is closed, the hook is at a first position and the actuating surface is at a corresponding first position. The apparatus is calibrated such that when the restrictor is in the closed position the actuating surface at the corresponding first position will not hit any protrusions, such as the hatchway rollers when the car is traveling between floors. When the car is at landing area (i.e., within a predetermined distance of a landing) and the door begins to move from the closed position to the open position, the hook begins to rotate in the first direction but stops rotating at the second position. The hook, which is coupled with the actuating surface, stops rotating because the actuating surface contacts the hatchway door rollers. When the hook stops in the second position the restrictor apparatus is in the unlocked position. When the restrictor apparatus is unlocked, the hook passes by the lug and the elevator door may freely slide open. If, however, the car is not at a landing area as the car door moves from the closed position toward the open position, the hook rotates in the first direction to the third position, at which the beak end will engage and lock against the lug and prevent the door from opening farther. When the car is not at a landing, the hook will not stop at the second position because the actuating surface is free to move away from the surface of the door and is not stopped by the hatchway door rollers.
For a better understanding of the invention, reference is made to the following detailed description of a preferred embodiment, taken in conjunction with the drawings accompanying the application.
REFERENCES:
patent: 1326440 (1919-12-01), Chaudoir
patent: 2899021 (1959-11-01), O&apos
Chin Paul T.
Olszewski Robert P.
Thyssen Dover Elevator
White & Case LLP
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