Patent Description:
Elevator systems include a variety of devices for providing control over movement of the elevator car. Elevator governors for protecting against over speed conditions are well known. Most elevator governors include a centrifugal mechanism located near the top of the hoistway. A governor rope extends along the length of the hoistway wrapping around a governor sheave associated with the centrifugal mechanism and an idler sheave associated with a tension weight near an opposite end of the hoistway. The elevator car is connected with the rope so that the rope moves as the elevator car moves. If the elevator car moves at a speed that is higher than desired, the speed of rotation of the governor sheave activates the centrifugal mechanism.

Governors in elevators systems are used for two purposes. One use of an elevator governor is for activating or dropping the machine brake and interrupting power to the machine motor in the event of an over speed condition. The other use is for activating elevator safeties that engage the guide rails, for example, in the event of a further over speed condition. Typically, elevator governors react to activate or drop the machine brake and interrupt power to the machine motor at nearly the same over speed condition, regardless of whether the elevator is travelling upwards or downwards within the hoistway. However, in high rise buildings where the elevators travel at high speeds, it may be desirable to have different overspeed conditions depending on the direction of travel of the elevator car.

<CIT> discloses an alternative speed governing device for an elevator capable of detecting different overspeed conditions for an ascending and descending elevator <CIT> discloses the features of the preamble of claim <NUM>. <CIT> discloses an elevator device comprising two separate governor units for when the elevator car is ascending or descending. <CIT> discloses a speed governor comprising a low speed direction governing part and a high speed direction governing part.

According to a first aspect of the present invention, an overspeed assembly for use with a governor assembly for limiting of an elevator system is provided in accordance with claim <NUM>.

In some embodiments the first overspeed condition and the second overspeed condition are distinct.

In some embodiments the pin is oriented substantially perpendicular to the rod.

In some embodiments when the elevator car is travelling in the first direction, the pin is in the first position and when the elevator car is travelling in the second direction, the pin is in the second position.

In some embodiments the overspeed assembly further comprises a controller operably coupled to the second magnet, wherein the controller energizes the second magnet to attract and repel the first magnet in response to a direction of travel of the elevator car.

According to the second aspect, a system is provided, comprising the overspeed assembly and a governor assembly for limiting of an elevator system, the governor assembly comprises: a governor sheave and a centrifugal mechanism movably mounted to the governor sheave, the rod being connected to the centrifugal mechanism.

In some embodiments the governor assembly further comprises a bell crank lever offset from governor sheave by a distance.

In some embodiments the bell crank lever is the first component.

In some embodiments the overspeed assembly further comprises a switch operably coupled to the bell crank lever, wherein when the elevator car is travelling in the first direction in the first overspeed condition, the pin engages the bell crank lever to operate the switch.

In some embodiments the overspeed assembly further comprises a motor for driving movement of the elevator car, wherein the switch is configured to at least one of interrupt a supply of power to the motor and apply a brake to the motor.

In some embodiments the overspeed assembly further comprises an elevator safety operably coupled to the bell crank lever wherein when the elevator car is travelling in the first direction in a third overspeed condition, the pin engages the bell crank lever to engage the elevator safety.

In some embodiments the bell crank lever includes a through hole, the pin being receivable within the through hole when the pin is in the second position.

In some embodiments the overspeed assembly further comprises a switch positioned adjacent the bell crank lever, wherein when the elevator car is travelling in the second direction in the second overspeed condition, the pin operates the switch.

According to a third aspect of the present invention, a method of controlling a speed of an elevator car within a hoistway is provided in accordance with claim <NUM>.

In some embodiments the first overspeed condition is different than the second overspeed condition.

In some embodiments operating the switch via engagement between an overspeed assembly and a first component in response to a first overspeed condition include further comprises at least one of interrupting a supply of power to a motor operable to move the elevator car and applying a brake to the motor.

In some embodiments the method further comprises initiating engagement of at least one elevator safety via engagement between the overspeed assembly and the first component in response to a third overspeed condition.

In some embodiments the third overspeed condition is a greater speed than the first overspeed condition.

In some embodiments operating another switch via the overspeed assembly in response to a second overspeed condition further comprises at least one of interrupting a supply of power to a motor operable to move the elevator car and applying a brake to the motor.

Referring now to <FIG>, an elevator system including an elevator car <NUM>, guide rails <NUM>, and a governor assembly <NUM> is illustrated. The governor assembly <NUM> includes a governor sheave <NUM>, a centrifugal mechanism <NUM>, a rope loop <NUM>, and a rope tensioning assembly <NUM> including a tensioning sheave <NUM>. The elevator car <NUM> travels on or is slidably connected to the guide rails <NUM> and travels within a hoistway (not shown). The governor sheave <NUM> and the centrifugal mechanism <NUM> are mounted, in the illustrated, non-limiting embodiment, at an upper end of the hoistway. The rope loop <NUM> is wrapped partially around the governor sheave <NUM> and partially around the tensioning sheave <NUM> (located in this embodiment at a bottom end of the hoistway). The rope loop <NUM> is also connected to the elevator car <NUM>, thereby ensuring that the angular velocity of the governor sheave <NUM> is related to the speed of the elevator car <NUM>.

In the elevator system shown in <FIG>, the governor assembly <NUM> acts to prevent the elevator car <NUM> from exceeding a set speed as it travels inside the hoistway. Although the governor assembly <NUM> shown in <FIG> is mounted at an upper end of the hoistway, the location and arrangement of the governor assembly <NUM> may vary across different embodiments of the present disclosure. For example, the governor assembly <NUM> may be mounted at any point along the rope loop <NUM> in the hoistway, including at the bottom, i.e. the pit, of the hoistway. In another embodiment, the governor assembly <NUM> may alternatively, be mounted to and move with the elevator car <NUM>. Such an alternative embodiment involves a static rope anchored at the top and tensioned by a weight or an elastic member at the bottom of the hoistway and wrapped partially around the tripping sheave <NUM> and an adjacent idler sheave.

With reference now to <FIG>, in an embodiment, the centrifugal mechanism <NUM> is operably coupled to the governor sheave <NUM>. For example, as is known in the art, the centrifugal mechanism <NUM> may include a connector associated with one or more centrifugal elements <NUM> configured to rotate with the governor sheave <NUM> as the elevator car <NUM> moves. As the elevator car <NUM> moves, the governor sheave <NUM> and the centrifugal mechanism <NUM> rotate. The resulting centrifugal force acting on the one or more centrifugal elements <NUM> due to this movement of the car <NUM> causes the connector and the centrifugal elements <NUM> to move relative to the axis of rotation. The centrifugal mechanism <NUM> described herein is intended as an example only, and it should be understood that any suitable centrifugal mechanism <NUM> is within the scope of the disclosure.

An example of an overspeed assembly <NUM> compatible for use with the governor sheave <NUM> of the governor assembly <NUM> is illustrated. As shown, the overspeed assembly <NUM> includes a rod <NUM> coupled at a first end <NUM> to a movable portion of the governor sheave <NUM>, and more specifically to a portion of the centrifugal mechanism <NUM>, such as a centrifugal element <NUM> for example. In an embodiment, the outward radial movement of the centrifugal elements <NUM> results in movement of the rod <NUM>. In the illustrated, non-limiting embodiment, the rod <NUM> is oriented generally parallel to an axis of rotation R of the centrifugal mechanism <NUM> and governor sheave <NUM> and is configured to translate along the axis R. However, embodiments where the rod <NUM> is oriented at another angle relative to the axis of rotation R are also contemplated herein. The rod <NUM> may be formed from any suitable material, including but not limited to plastic for example.

A pin <NUM> extends through an opening formed in the body of the rod <NUM>, in an orientation generally perpendicular to the axis of rotation R of the centrifugal mechanism <NUM>. The pin <NUM> may be formed from any suitable material, such as plastic or metal for example. A head <NUM> arranged at a first end of the pin <NUM> has a diameter greater than the diameter of the opening formed in the rod <NUM>. As a result, engagement between the head <NUM> and the rod <NUM> limits movement of the pin <NUM> relative to rod <NUM> in a first direction. A primary magnet <NUM>, such as a permanent magnet for example, is mounted to a second, opposite end of the pin <NUM>. Similarly, the magnet <NUM> has a diameter greater than the diameter of the opening formed in the rod <NUM>. As a result, engagement between the magnet <NUM> and the rod <NUM> limits movement of the pin <NUM> relative to rod <NUM> in a second, opposite direction.

Mounted within the hoistway generally adjacent the second end of the pin <NUM> is a secondary magnet <NUM>. In an embodiment, the magnet <NUM> is an electromagnet. However any suitable type of magnet <NUM> is within the scope of the disclosure. The magnet <NUM> is selectively operable to generate a magnetic force configured to either attract or repel the magnet <NUM> coupled to the second end of the pin <NUM>. This attraction or repulsion is used to move the pin <NUM> between a first position (<FIG> and <FIG>) and a second position (<FIG> and <FIG>) relative to the rod <NUM>. The desired position of the pin <NUM> may be selected, for example, based on a direction of travel of the elevator car <NUM>. In the illustrated, non-limiting embodiment, the pin <NUM> is in the first position when the elevator car <NUM> is travelling in a first, downward direction and is in the second position when the elevator car <NUM> is travelling in a second, upward direction within the hoistway.

The governor assembly <NUM> includes a bell crank lever <NUM> mounted within the hoistway at a position offset from the centrifugal mechanism <NUM> by a distance. As a result, the rod <NUM> is positioned generally between the centrifugal mechanism <NUM> and the bell crank lever <NUM>. As shown, the bell crank level <NUM> includes an integrally formed first portion <NUM> and second portion <NUM>. In the illustrated, non-limiting embodiment, the first portion <NUM> is oriented substantially parallel to the pin <NUM> and the second portion <NUM> is oriented substantially parallel to the rod <NUM> such that the interface <NUM> between the first portion <NUM> and the second portion <NUM> defines a bend in the bell crank lever <NUM>. A distal end <NUM> of the second portion <NUM> of the bell crank lever <NUM> is pivotally coupled to a connector <NUM> associated with a release lever (not shown) and a first overspeed actuation switch <NUM>. In addition, the bell crank lever <NUM> is configured to pivot about an axis X (best shown in <FIG>) defined at the interface <NUM> between the first and second portions <NUM>, <NUM> and oriented generally perpendicular to both the rod <NUM> and pin <NUM>.

In an embodiment, best shown in <FIG> and <FIG>, a cutout or through hole <NUM> is formed in the first portion <NUM> of the bell crank lever <NUM>. The cut out <NUM> is generally equal or larger in length and width than the pin <NUM> including both the head <NUM> and the magnet <NUM>. In the illustrated, non-limiting embodiment, the through hole <NUM> is positioned adjacent the interface <NUM> between the first and second portions <NUM>, <NUM>. Accordingly, the through hole <NUM> is generally aligned with the pin <NUM> when the pin <NUM> is in the second position.

With specific reference now to <FIG> and <FIG>, upon determining that the car <NUM> is configured to move in a first direction, such as a downward direction for example, a controller <NUM> (<FIG>) operably coupled to the secondary magnet <NUM> communicates a signal to the magnet <NUM>, or a power source associated therewith. As a result, the secondary magnet <NUM> is energized and the resulting magnetic field has an opposite polarization as the magnetic field of the magnet <NUM> mounted to the pin <NUM>. The interaction between the magnetic fields of the primary and secondary magnets <NUM>, <NUM> causes the pin <NUM> to translate within the opening, relative to the rod <NUM>, to a first position. In the first position, the head <NUM> of the pin <NUM> may be arranged generally adjacent or in direct contact with a surface of the rod <NUM>. Further, in the illustrated, non-limiting embodiment, the length of the pin <NUM> is selected such that the second end or magnet <NUM> of the pin <NUM> extends axially beyond the free end <NUM> of the first portion <NUM> of the bell crank lever <NUM> when in the first position. Accordingly, in the first position, the pin <NUM> is not aligned with the through hole <NUM> formed in the first portion <NUM> of the bell crank lever <NUM>.

As the speed of the elevator car <NUM> travelling in the first direction increases, the distance that the rod <NUM> extends from the governor sheave <NUM> also increases. Accordingly, the distance between the rod <NUM> and the bell crank lever <NUM> similarly decreases. If the speed of the elevator car <NUM> travelling in the first direction exceeds a first overspeed threshold, the movement of the rod <NUM> causes the pin <NUM> to apply a force to the first portion <NUM> of the bell crank lever <NUM>. This force rotates the bell crank lever <NUM> about its axis X, as indicated by arrow A, such that a corresponding force is applied to the connector <NUM> to operate the overspeed switch <NUM>. Operation of the switch <NUM> may be configured to interrupt the power being supplied to a motor <NUM> (see <FIG>) driving movement of the elevator car <NUM> within the hoistway and/or apply a brake <NUM> to the motor <NUM> to slow movement of the elevator car <NUM>.

If the speed of the elevator car <NUM> travelling in the first direction exceeds a second overspeed threshold, the further movement of the rod <NUM> relative to the centrifugal mechanism <NUM>, and the resulting engagement between the pin <NUM> and the bell crank lever <NUM>, causes the bell crank lever <NUM> to rotate further about its axis X, in the direction indicated by arrow A. This further rotation causes the connector <NUM> to operate a jaw mechanism, illustrated at <NUM> in <FIG>, and initiate engagement of the elevator safeties. Through this activation, one or more elevator safeties are moved into frictional engagement with the guide rails <NUM> supporting the elevator car <NUM>, as is known in the art.

Because the distance that the rod <NUM> extends from the governor sheave <NUM> and/or centrifugal mechanism <NUM> also increases as the speed of the elevator car <NUM> increases and engagement between the pin <NUM> in the first position and the bell crank lever <NUM> is used to indicate an overspeed condition, the distance between the centrifugal mechanism <NUM> and the first portion <NUM> of the bell crank lever <NUM> is selected based on the threshold of the first overspeed condition. Accordingly, the position of the bell crank lever <NUM> may be located either closer to or further from the centrifugal mechanism <NUM> to reduce or increase the threshold of the first overspeed condition, respectively. Alternatively, or in addition, because the radial movement of the centrifugal elements <NUM> is configured to control the translation of the rod <NUM> relative to the bell crank lever <NUM>, this movement of the centrifugal elements <NUM> may be controlled to achieve a desired threshold of the first overspeed condition.

With reference to <FIG> and <FIG>, upon determining that the car <NUM> is configured to move in a second direction, such as an upward direction for example, the controller <NUM> generates a signal to energize the secondary magnet <NUM> and create a magnetic field with a similar polarization to the magnet <NUM> affixed to the pin <NUM>. The interaction between the magnetic fields of the magnets <NUM>, <NUM> causes the pin <NUM> to translate within the opening, relative to the rod <NUM>, to the second position. In the second position, the magnet <NUM> of the pin <NUM> is arranged generally adjacent or in direct contact with a surface of the rod <NUM>. Further, in the second position, the pin <NUM> is generally aligned with the through hole <NUM> formed in the first portion <NUM> of the bell crank lever <NUM>.

As the speed of the elevator car <NUM> moving in the second direction increases, the distance that the rod <NUM> extends from the centrifugal mechanism <NUM> also increases. The rod <NUM> is configured to move in the same direction relative to the centrifugal mechanism <NUM> regardless of whether the elevator car <NUM> is moving in the first direction or the second direction. Because the threshold associated with an overspeed condition during movement of the elevator car <NUM> in the second direction is greater than the threshold associated with an overspeed condition during movement of the elevator car <NUM> in the first direction, the rod <NUM> and pin <NUM> will be received within and ultimately extend through the through hole <NUM> formed in the bell crank lever <NUM>.

As the speed of the elevator car <NUM> travelling in the second direction increases, and ultimately exceeds a threshold associated with an overspeed condition, the distal end of the rod <NUM> will contact an overspeed switch <NUM>. Operation of the overspeed switch <NUM> will activate or drop the machine brake and interrupt power to the machine motor, as is known in the art.

The position of the overspeed switch <NUM> relative to the centrifugal mechanism <NUM> and the movement of the rod <NUM> is selected based on the threshold of the overspeed condition when the elevator car is travelling in the second direction. Accordingly, the position of the overspeed switch <NUM> may be located either closer to or further from the centrifugal mechanism <NUM> to reduce or increase the threshold of the overspeed condition, based on earlier or later actuation by the rod <NUM>.

The overspeed assembly <NUM> illustrated and described herein provides a first overspeed threshold for travel of an elevator car <NUM> in a first direction and a second, distinct overspeed threshold for travel of an elevator car <NUM> in a second, opposite direction. In an embodiment, the first overspeed threshold for travel in the down direction is between <NUM> and <NUM>/s and the second overspeed threshold for travel in the up direction is between <NUM> and <NUM>/s. However, any speeds are within the scope of the disclosure. Further, governor assemblies <NUM> in an existing elevator system may be adapted to include the overspeed assembly <NUM> with minimal changes to the existing components.

Claim 1:
An overspeed assembly (<NUM>) for use with a governor assembly (<NUM>) for limiting of an elevator system (<NUM>), the overspeed assembly (<NUM>) comprising:
a rod (<NUM>) movable relative to the governor assembly (<NUM>) in response to a speed of an elevator car (<NUM>);
a pin (<NUM>) coupled to the rod (<NUM>);
characterized by the pin (<NUM>) being movable between a first position and a second position based on a direction of travel of the elevator car (<NUM>), wherein the pin (<NUM>) is configured to engage a first component (<NUM>) to indicate a first overspeed condition when the elevator car (<NUM>) is travelling in a first direction and the pin (<NUM>) is configured to engage a second component (<NUM>) to indicate a second overspeed condition when the elevator car (<NUM>) is travelling in a second, opposite direction;
wherein the pin (<NUM>) further comprises a first magnet (<NUM>), and the overspeed assembly (<NUM>) includes a second magnet (<NUM>), the second magnet (<NUM>) being selectively operable to attract and repel the first magnet (<NUM>) to move the pin (<NUM>) between the first position and the second position.