Patent Description:
The elevator car doors and the hoistway doors have locks that prevent the doors from being improperly opened. The elevator car door lock typically includes a relatively expensive mechanism. For example, the elevator car door lock may include a solenoid to move the lock between a locked and unlocked condition. In addition to the component cost of typical mechanisms, door locks tend to increase the cost of maintaining an elevator system. It is believed that elevator door system components, such as the locks, account for approximately <NUM>% of elevator maintenance requests and <NUM>% of callbacks. One contributing factor to such issues is the way in which typical elevator car door locks are designed. <CIT> discloses a microprocessor-based car door locking system which includes an electromechanical door lock for elevator car doors having a latch-type rotary solenoid to move a plunger into locked and unlocked positions. <CIT> discloses a device for checking or adjusting a depth of engagement of a locked elevator door lock, wherein the door lock has a catch engaged with a stop, which can be fixed to the catch and have a region for supporting the stop. <CIT> discloses a locking and unlocking device which has a stationary unit arranged so that it delimits a movement space of a moving part and a unit for locking and unlocking a door. <CIT> discloses an arrangement whereby an electromagnet is provided at one of the door stops of a landing door. <CIT> discloses an elevator device that allows a door locking device to be unlocked from a landing in situations when power cannot be supplied.

According to a first aspect of the present invention there is provided an elevator door lock as defined by claim <NUM>.

In an example embodiment of the elevator door lock of the previous paragraph, the locking surface is near a first end of the latch, the portion of the latch that is magnetically attracted by the magnet is near a second end of the latch, and the latch pivots about a pivot axis as the latch moves between the locking position and the released position.

In an example embodiment of the elevator door lock of any of the previous paragraphs, a mass of the latch is greater near the second end, gravity biases the second end in a downward direction to move the latch into the locking position, and the magnet attracts the portion against the bias of gravity to move the latch into the released position.

In an example embodiment of the elevator door lock of any of the previous paragraphs, the magnet moves in one direction between the first position and the second position, and the latch moves in a different direction between the locking position and the released position.

In an example embodiment of the elevator door lock of any of the previous paragraphs, the magnet moves in a horizontal direction between the first position and the second position, and the portion of the latch moves in a vertical direction.

In an example embodiment of the elevator door lock of any of the previous paragraphs, the magnet is a first distance from the portion of the latch when the magnet is in the first position, the magnet is a second distance from the portion of the latch when the magnet is in the second position, and the second distance is shorter than the first distance.

According to a second aspect of the present invention, there is provided an elevator door assembly includes the elevator door lock of any of the previous paragraphs, a door, and a door mover configured to move the door between open and closed positions. The magnet is associated with the door mover for movement between a first position and a second position. The magnet does not attract the portion of the latch when the magnet is in the first position. The latch is in the locking position when the magnet is in the first position. The magnet attracts the portion of the latch when the magnet is in the second position and the latch is in the released position when the magnet is in the second position.

In an example embodiment of the elevator door assembly of the previous paragraph, the stop is situated in a fixed position. The locking surface of the latch engages the stop when the latch is in the locking position. The door is prevented from movement out of the closed position when the locking surface engages the stop, and the magnet attracts the portion of the latch to move the locking surface away from the stop when the magnet is in the second position.

In an example embodiment of the elevator door assembly of any of the previous paragraphs, the magnet is supported on at least one guide and the magnet moves along the guide as the magnet moves between the first position and the second position.

In an example embodiment of the elevator door assembly of any of the previous paragraphs, the guide comprises at least one rail including a low friction material and the magnet slides along the low friction material.

In an example embodiment of the elevator door assembly of any of the previous paragraphs, the magnet moves in a horizontal direction between the first position and the second position, and the portion of the latch moves in a vertical direction as the latch moves between the locking position and the released position.

In an example embodiment of the elevator door assembly of any of the previous paragraphs, the latch is supported for pivotal movement relative to the stop between the locking position and the released position.

In an example embodiment of the elevator door assembly of any of the previous paragraphs, the locking surface is near a first end of the latch, the portion of the latch that is magnetically attracted by the magnet is near a second end of the latch, and a mass of the latch is greater near the second end. Gravity urges the second end in a downward direction to move the latch into the locking position when the magnet is in the first position, and the magnet attracts the portion against the bias of gravity to move the latch into the released position when the magnet is in the second position.

In an example embodiment of the elevator door assembly of any of the previous paragraphs, the latch is supported for movement with the door as the door moves between the open position and the closed position, the magnet moves with a corresponding portion of the door mover as the door moves between the open position and the closed position, and the portion of the latch remains attracted by the magnet during movement of the door between the open position and the closed position.

In an example embodiment of the elevator door assembly of any of the previous paragraphs, the magnet comprises a permanent magnet, and the portion of the latch comprises a ferromagnetic material.

<FIG> schematically illustrates selected portions of an elevator car <NUM>. Elevator car doors <NUM> are shown in a closed position. A door mover <NUM> selectively moves the doors <NUM> between the closed position and an open position under appropriate circumstances, such as when the elevator car <NUM> is at a landing and a passenger wants to board or exit the elevator car <NUM>. The example door mover includes a belt <NUM> that is coupled to door hangers <NUM>. As the belt <NUM> moves, the door hangers <NUM> and the doors <NUM> move.

At least one of the doors <NUM> includes a door lock <NUM> that prevents the doors <NUM> from being improperly opened. A vane <NUM> couples the elevator car doors <NUM> to hoistway doors (not illustrated) in a known manner so that the hoistway doors move together with the elevator car doors <NUM> when the door lock <NUM> is unlocked and the door mover <NUM> cause door movement.

The door lock <NUM> is supported on the door hanger <NUM> of the corresponding door <NUM>. As shown in <FIG> and <FIG>, the door lock <NUM> includes a latch <NUM> that has a locking surface <NUM>. A stop <NUM> is situated in a fixed position. In the illustrated example, the stop <NUM> is supported on a door lintel <NUM> that remains stationary relative to the elevator car <NUM>. The locking surface <NUM> engages the stop <NUM> when the latch <NUM> is in a locking position, which is shown in <FIG> and <FIG>. The engagement of the locking surface <NUM> and the stop <NUM> prevents the door on the right in <FIG> from being moved to the right (according to the drawings) from the illustrated closed position to an open position.

The door lock <NUM> includes a magnet <NUM> that interacts with a portion <NUM> of the latch <NUM> to selectively move the latch <NUM> from the locking position into a released position, which is shown in <FIG>. The magnet <NUM> in this example embodiment is a permanent magnet and the portion <NUM> of the latch <NUM> comprises a ferromagnetic material.

In the illustrated example embodiment, the magnet <NUM> is associated with the belt <NUM> of the door mover <NUM> so the magnet moves with the belt <NUM>. The magnet <NUM> moves between a first position relative to the latch <NUM> as shown in <FIG> and <FIG> and a second position as shown in <FIG>. In this embodiment, the magnet <NUM> is supported by a guide <NUM> that includes at least one rail. The magnet <NUM> slides along the guide <NUM> as the magnet <NUM> moves between the first and second positions. The guide <NUM> includes a low friction material on at least the surface that the magnet <NUM> slides along as the magnet <NUM> moves.

When the doors <NUM> are closed and the magnet <NUM> is in the first position shown in <FIG> and <FIG>, the latch <NUM> is in the locking position. In the illustrated example embodiment, the locking surface <NUM> is near a first end of the latch <NUM> and the portion <NUM> is near a second end. A mass of the first end of the latch <NUM> is less than a mass of the second end. In the illustrated example, the portion <NUM> includes a weight that establishes a greater mass near the second end of the latch <NUM>. In other embodiments, the latch <NUM> is made with greater mass near the second end.

Gravity urges the latch <NUM> into the locking position because of the imbalance between the mass of the first and second ends of the latch <NUM>. The latch <NUM> is supported on the door hanger <NUM> to pivot about a pivot axis <NUM> relative to the door hanger <NUM>. The latch <NUM> pivots about the pivot axis <NUM> as it moves between the locking position (<FIG> and <FIG>) and the released position (<FIG>).

When the door mover <NUM> initiates opening the doors <NUM>, the belt <NUM> moves (to the left according to the drawings) and the magnet <NUM> moves from the first position shown in <FIG> and <FIG> toward a second position shown in <FIG>. As belt <NUM> moves, the magnet <NUM> slides along the guide <NUM> and approaches the portion <NUM>. When the magnet <NUM> is close enough to the portion <NUM> for the magnetic field of the magnet <NUM> to attract the portion <NUM>, the second end of the latch <NUM> pivots toward the magnet <NUM> (upward according to the drawings). Such movement caused by the magnetic attraction of the magnet <NUM> cause the locking surface <NUM> to pivot away from the stop <NUM> (downward according to the drawings). As the locking surface <NUM> moves away from the stop <NUM>, the latch <NUM> moves from the locking position to the released position.

Movement of the belt <NUM>, the position of the magnet <NUM> relative to the belt <NUM>, and the position of the portion <NUM> relative to the door hanger are timed so that some initial movement of the belt <NUM> causes the latch <NUM> to move from the locking position shown in <FIG> and <FIG> into the released position shown in <FIG> before the door mover <NUM> urges the doors <NUM> out of the open position. In the first position, the magnet <NUM> does not overlap the portion <NUM> of the latch <NUM> and does not urge the latch <NUM> to pivot against the pull of gravity out of the locking position. The magnet <NUM> moves based on operation of the door mover <NUM> into sufficiently close proximity or overlap with the portion <NUM> where the magnetic attraction force of the magnet <NUM> draws the portion <NUM> toward the magnet <NUM> to move the latch <NUM> from the locking position into the released position.

The timing of moving the latch <NUM> into the released position is coordinated with expansion of the vane <NUM>, which operates a hoistway door lock (not illustrated) to unlock the hoistway door at approximately the same time that the elevator car doors <NUM> are unlocked. The vane <NUM> is shown in <FIG> in a collapsed or contracted state and in an expanded state in <FIG>. Those skilled in the art will recognize how such a vane can cooperate with a hoistway door coupler and lock mechanism to unlock the hoistway doors.

In the illustrated example embodiment, the magnet <NUM> remains in the overlapping, aligned position relative to the portion <NUM> shown in <FIG> while the doors <NUM> are open. The door hanger <NUM> and door <NUM> move with the belt <NUM> in a manner that the magnet <NUM> remains in the second position where the magnet <NUM> retains the latch <NUM> in the released position.

As the doors <NUM> return to the closed position, the belt <NUM> and the magnet <NUM> move from the positions shown in <FIG> into the positions shown in <FIG> and <FIG>. The magnet <NUM> moves far enough away from the portion <NUM> so that the magnetic pull of the magnet <NUM> no longer counteracts the pull of gravity and the latch <NUM> automatically or naturally pivots back into the locking position shown in <FIG>. In that manner, the door lock <NUM> secures the doors <NUM> in a locked condition once the doors <NUM> are closed.

The guide <NUM> provides support beneath the mass of the magnet <NUM> to avoid strain on the belt <NUM>. The guide <NUM> also facilitates expected and smooth movement of the magnet <NUM>. Another feature of the guide <NUM> is that it facilitates decoupling the magnet <NUM> and the portion <NUM> because the guide <NUM> provide some spacing between the magnet <NUM> and the portion <NUM>. Without any spacing, the magnet <NUM> and the portion <NUM> would directly contact each other, making separation less efficient.

In some embodiments, the guide <NUM> is made of a material that provides sound dampening to avoid an audible clicking noise as the magnet <NUM> draws the portion <NUM> toward the magnet <NUM> as the latch <NUM> pivots into the released position.

Elevator door locks like the illustrated example embodiment provide a robust and efficient door lock that is less prone to needing adjustment or repair over the service life of the elevator car <NUM>. Elevator door locks consistent with this description can also be less expensive than other types of locks.

Claim 1:
An elevator door lock (<NUM>), comprising:
a latch (<NUM>) that is moveable between a locking position and a released position, the latch (<NUM>) including a locking surface (<NUM>) configured to engage a stop (<NUM>) when the latch (<NUM>) is in the locking position; characterized in that the elevator door lock (<NUM>) comprises:
a magnet (<NUM>) that is supported (<NUM>) for movement relative to the latch (<NUM>) between a first position and a second position and situated to magnetically attract a portion (<NUM>) of the latch (<NUM>) to selectively move the latch (<NUM>) from the locking position into the released position; wherein:
the latch (<NUM>) is in the locking position when the magnet (<NUM>) is in the first position,
the magnet (<NUM>) attracts the portion (<NUM>) of the latch (<NUM>) when the magnet (<NUM>) is in the second position, and
the latch (<NUM>) is in the released position when the magnet (<NUM>) is in the second position.