Frictionless safety brake actuator

Abstract

A frictionless safety brake actuator for use in an elevator system includes at least two stators, a magnet array positioned between the stators, a linkage attached to the magnet array, and a biasing arrangement. The magnet array includes a first magnet set and a second magnet set including at least one magnet each and at least three magnets in total. The magnets of the first magnet set are arranged in a stack alternately with the magnets of the second magnet set. The magnets in the first magnet set are electromagnets. The magnet array generates a magnetic field. The electromagnets in the first magnet set and the magnets in the second magnet set each have a respective orientation such that when forward current is supplied to the electromagnets, the magnetic field is stronger on a first side of the magnet array than on a second, opposite side of the magnet array, and when reverse current is supplied to the electromagnets, the magnetic field is stronger on the second side of the magnet array than on the first side. The stators each include a respective array of discrete magnetic elements having a staggered configuration.

Description

Technical Field

[0001] This disclosure relates to a frictionless safety brake actuator for use in an elevator system, and an elevator system including such a frictionless safety brake actuator. Background Technology

[0002] It is known in the art to install safety brakes on elevator components that move along guide rails to bring the elevator components to a quick and safe stop, especially in emergency situations. In many elevator systems, the elevator car is lifted by a tensioning member, whose movement is guided by a pair of guide rails. Typically, a speed controller is used to monitor the speed of the elevator car. According to standard safety regulations, such elevator systems must include an emergency braking device (called a safety brake, "safety mechanism," or "safety device") that can prevent the elevator car from moving up or down by clamping the guide rails, even if the tensioning member breaks. Safety brakes may also be installed on the counterweight or other components that move along the guide rails.

[0003] Electronic safety actuators (ESAs) are now commonly used instead of mechanical governors to trigger safety brakes, such as those using electronic or electrical controllers. An ESA typically actuates the safety brake by the controlled release of a magnet (permanent magnet or electromagnet) to drag against the guide rail, and utilizes the resulting friction to pull up the linkage attached to the safety brake. This reliance on the frictional interaction between the magnet and the guide rail presents several potential problems, especially in high-rise elevator systems, as the interaction leads to wear on the guide rail and can cause spalling and debris accumulation.

[0004] To address these and other issues, frictionless safety brake actuators can be used. In frictionless safety brake actuators, a different mechanism is used to actuate the safety brake, in addition to the frictional interaction between the magnet and the guide rail. For example, in some frictionless safety brake actuators, spring force is controlled to pull the linkage that engages the safety brake. However, after the safety brake has engaged, the frictionless safety brake actuator needs to be reset to return the linkage and the safety brake to their inactive positions.

[0005] A reliable and convenient reset mechanism is needed for such frictionless safety brake actuators. Summary of the Invention

[0006] When viewed from a first aspect, this disclosure provides a frictionless safety brake actuator for use in an elevator system, comprising:

[0007] At least two stators, comprising a first stator and a second stator extending in corresponding substantially parallel planes;

[0008] A magnet array, positioned between the first and second stators;

[0009] A linkage mechanism capable of actuating a safety brake to frictionally engage with elevator guide rails, wherein the linkage mechanism is attached to a magnet array, and wherein the magnet array is movable along an axis substantially parallel to the extensions of the first and second stators between a first position in which the linkage mechanism is actuated and a second position in which the linkage mechanism is not actuated; and

[0010] A biasing arrangement, which is configured to apply a biasing force to the magnet array to bias the magnet array toward a first position;

[0011] The magnet array includes a first magnet group and a second magnet group, wherein the first and second magnet groups each include at least one magnet and a total of at least three magnets, wherein the magnets(multiple) of the first magnet group and the magnets(multiple) of the second magnet group are arranged alternately in a stack, wherein said or each magnet in the first magnet group is an electromagnet, and wherein the magnet array generates a magnetic field.

[0012] The electromagnets in the first magnet group and the magnets in the second magnet group each have a corresponding orientation, such that when a forward current is supplied to the electromagnets in the first magnet group, the magnetic field is stronger on the first side of the magnet array adjacent to the first stator than on the second opposite side of the magnet array adjacent to the second stator, and when a reverse current is supplied to the electromagnets in the first magnet group, the magnetic field is stronger on the second side of the magnet array than on the first side of the magnet array.

[0013] The first and second stators each include a corresponding array of discrete magnetic elements extending parallel to the axis, wherein the discrete magnetic elements have an interleaved configuration in which the discrete magnetic elements on the first stator are displaced relative to the discrete magnetic elements on the second stator in the direction of the axis.

[0014] This aspect of the disclosure extends to elevator systems including elevator guide rails, an elevator car, a frictionless safety brake actuator, and a safety brake, wherein the frictionless safety brake actuator and the safety brake are mounted to the elevator car for movement along the guide rails during elevator car use; wherein the frictionless safety brake actuator includes:

[0015] At least two stators, comprising a first stator and a second stator extending in corresponding substantially parallel planes;

[0016] A magnet array, positioned between the first and second stators;

[0017] A linkage mechanism capable of actuating a safety brake to frictionally engage with elevator guide rails, wherein the linkage mechanism is attached to a magnet array, and wherein the magnet array is movable along an axis substantially parallel to the extensions of the first and second stators between a first position in which the linkage mechanism is actuated and a second position in which the linkage mechanism is not actuated; and

[0018] A biasing arrangement, which is configured to apply a biasing force to the magnet array to bias the magnet array toward a first position;

[0019] The magnet array includes a first magnet group and a second magnet group, wherein the first and second magnet groups each include at least one magnet and a total of at least three magnets, wherein the magnets(multiple) of the first magnet group and the magnets(multiple) of the second magnet group are arranged alternately in a stack, wherein said or each magnet in the first magnet group is an electromagnet, and wherein the magnet array generates a magnetic field.

[0020] The electromagnets in the first magnet group and the magnets in the second magnet group each have a corresponding orientation, such that when a forward current is supplied to the electromagnets in the first magnet group, the magnetic field is stronger on the first side of the magnet array adjacent to the first stator than on the second opposite side of the magnet array adjacent to the second stator, and when a reverse current is supplied to the electromagnets in the first magnet group, the magnetic field is stronger on the second side of the magnet array than on the first side of the magnet array.

[0021] The first and second stators each include a corresponding array of discrete magnetic elements extending parallel to the axis, wherein the discrete magnetic elements have an interleaved configuration in which the discrete magnetic elements on the first stator are displaced relative to the discrete magnetic elements on the second stator in the direction of the axis.

[0022] This aspect of the disclosure extends to a method for resetting a frictionless safety brake actuator according to the disclosure, the method comprising:

[0023] Alternating current is applied to (multiple) electromagnets of the first group of magnets until the magnet array has moved to the second position.

[0024] The method may include applying alternating current in response to a reset signal.

[0025] As will be apparent from this disclosure, when alternating current is applied to the electromagnet(s) in the first magnet group in use, the alternating current causes the strongest region of the magnetic field to alternate between the first and second sides of the magnet array, such that the magnet array is alternately attracted to the discrete magnetic elements of the first and second stators, thereby causing the magnet array to move against the bias force toward the second position due to the interleaved structure of the discrete magnetic elements. The magnet array can thus move to the second position to move the linkage to the non-actuated position, thereby disengaging the safety brake. Therefore, the frictionless safety brake actuator can be reset by applying alternating current to the electromagnet(s) of the first magnet group.

[0026] It will also be recognized that the presence of the biasing arrangement for biasing the magnet array to the first position means that the linkage can be actuated (e.g., by deactivating the electromagnets) by controlling the electromagnet(s) in the first magnet group (and optionally, if present, any electromagnet in the second magnet group). Therefore, the frictionless safety brake actuator provides actuation to the safety brake with the aid of frictional contact between the frictionless safety brake actuator and the guide rail. This provides the advantage that the actuation of the safety brake is unaffected by the state of the elevator guide rail, so any potential debris from the elevator shaft or dirt from the elevator guide rail will not interfere with the actuation of the frictionless safety brake actuator. Furthermore, the position of the frictionless safety brake actuator is not limited by the need for contact with the guide rail during actuation and can be positioned anywhere on the elevator components where the linkage can then actuate the safety brake. In some examples, no part of the frictionless safety brake actuator is in frictional contact with the elevator guide rail.

[0027] It is known in the art how to arrange an array of magnets to generate a stronger magnetic field on one side of the array than on the opposite side. An example of such an array may be referred to in the art as a Heilbeck array. For example, multiple magnets may be arranged in an array extending along a first axis. Each magnet may have an orientation that rotates about a second axis perpendicular to the first axis relative to the orientation of its adjacent magnets in the array. The first and second axes define a plane containing the axes, and such an array generates a stronger magnetic field on one side of the plane than on the opposite side. The field on the opposite side can be substantially suppressed, for example, close to zero.

[0028] It should be understood that the term "orientation" or "magnetic orientation" used herein for a magnet refers to the orientation of the magnetic axis extending from the south pole to the north pole of the magnet. It will be understood that the orientation of an electromagnet depends on the direction of the current applied to it, and that the magnetic orientation of an electromagnet is antiparallel when a forward current is applied to it compared to when a reverse current is applied. Accordingly, if the orientation of an electromagnet is described as being parallel or perpendicular to a specified direction, this applies to both the forward and reverse current directions. When a magnet is described as being "oriented" in one direction, this means that the magnetic orientation of the magnet is in the specified direction. It should be understood that when an orientation is described as being in a specified direction, such as parallel or perpendicular to a direction, this does not necessarily require a precise orientation in the specified direction, but may include an orientation that is substantially oriented in the specified direction. Each magnet in the first and second groups of magnets may be straight or substantially straight, such as a bar magnet, or an electromagnet having a core and / or coil having a straight, elongated axis extending through its center.

[0029] The respective orientations of the electromagnets (multiples) of the first magnet group and the magnets (multiples) of the second magnet group can both be located in a plane parallel to the axis and perpendicular to the first and second stators (i.e., the plane in which the stators are located).

[0030] The first and second magnet groups may include a total of N magnets arranged at N positions marked from n=1 to n=N along the axis, where N is at least 3, for example at least 4, for example at least 5, at least 6, for example at least 7. N may be greater than 3, for example 4, 5, 6, or 7. N may be an odd number. Positions marked by odd numbers n may be occupied by electromagnets of the first magnet group, and positions marked by even numbers n may be occupied by magnets of the second magnet group. Alternatively, positions marked by even numbers n may be occupied by electromagnets of the first magnet group, and positions marked by odd numbers n may be occupied by magnets of the second magnet group.

[0031] The electromagnets of the first magnet group and the magnets of the second magnet group can be oriented such that: when a forward current is applied to the electromagnets of the first magnet group, for n=1 to n=N-1, the (n+1)th magnet has an orientation that is rotated 90° relative to the orientation of the nth magnet in a first rotational direction, and when a reverse current is applied to the electromagnets of the first magnet group, for n=1 to n=N-1, the (n+1)th magnet has an orientation that is rotated 90° relative to the nth magnet in a second rotational direction opposite to the first rotational direction.

[0032] In some examples, the electromagnets(s) of the first magnet group may be oriented perpendicular to the axis, and the magnets(s) of the second magnet group may be oriented parallel to the axis. In other examples, the electromagnets(s) of the first magnet group may be oriented parallel to the axis, and the magnets(s) of the second magnet group may be oriented perpendicular to the axis.

[0033] In one set of examples, the magnet array can consist of three magnets, where:

[0034] i) The three magnets include first and second electromagnets belonging to a first magnet group and an inserted magnet belonging to a second magnet group, wherein the inserted magnet is positioned between the first and second electromagnets in the stack; or

[0035] ii) The three magnets include first and second magnets belonging to the second magnet group and an interposed electromagnet belonging to the first magnet group, wherein the interposed electromagnet is positioned between the first and second magnets in the stack.

[0036] In alternative i), when a forward current is applied to the first and second electromagnets, and when a reverse current is applied to the first and second electromagnets, the first and second electromagnets may be oriented perpendicular to the first axis and antiparallel to each other. For example, the first and second electromagnets may each have a corresponding orientation such that when a forward current is applied to the first and second electromagnets, the first electromagnet is oriented toward the first stator and the second electromagnet is oriented toward the second stator, and when a reverse current is applied to the first and second electromagnets, the first electromagnet is oriented toward the second stator and the second electromagnet is oriented toward the first stator. In alternative i), the inserted magnet may have an orientation parallel to the axis, for example, pointing toward a first position or a second position.

[0037] In alternative ii), the inserted electromagnet may be oriented parallel to the first axis. For example, the orientation of the inserted electromagnet may point to a first position when a forward current is applied to it, and to a second position when a reverse current is applied to it. In alternative ii), the first and second magnets may be oriented perpendicular to the first axis and antiparallel to each other; for example, the first magnet may have an orientation pointing towards the first stator, and the second magnet may have an orientation pointing towards the second stator.

[0038] A magnet array can be constructed (e.g., by selecting the total number of magnets, their respective strengths, their orientations, etc.) and / or the peak voltage of the alternating current can be selected such that the magnetic field on the second side of the magnet array is substantially zero during the peak forward current, and the magnetic field on the first side of the magnet array is substantially zero during the peak reverse current.

[0039] Unlike the electromagnets(s) of the first magnet group, the magnets(s) of the second magnet group(s) may each comprise or consist of any kind of magnet whose orientation is constant, for example, not configured to change by the application of alternating current. For example, the magnets(s) of the second magnet group(s) may each comprise or consist of a permanent magnet or an electromagnet having a direct current applied to it during use. In some examples, said or each magnet in the second magnet group is a permanent magnet.

[0040] The first and second stators can be separate structures, but this is not required. For example, the first and second stators can be two parts of a single structure shaped to provide opposing parallel support surfaces for an array of discrete magnetic elements.

[0041] The first and second stators may be made of a magnetic material, such as a ferromagnetic material (e.g., iron). The arrays of discrete magnetic elements of the first and second stators may each include a corresponding array of protrusions of magnetic material extending from the respective stator toward the magnet array.

[0042] The array of discrete magnetic elements may each include, for example, a corresponding array of permanent magnets formed or mounted within or on a respective stator. The stator may be made of a non-magnetic material. The discrete magnetic elements may include shielded coils.

[0043] As will be understood from this disclosure, having discrete magnetic elements means that the stator may have regions or portions attracted by the magnetic field of the magnet array, wherein said regions or portions are separated by gap regions or portions less attracted by or not attracted by the magnetic field of the magnet array, for example, due to being non-magnetic or less magnetic, further away from the magnet array (e.g., recessed between protrusions), or gaps in the stator, etc.

[0044] The discrete magnetic elements of the first and second stators may be uniformly spaced along the axis at a distance S, for example, wherein the distance is measured between corresponding points (e.g., center points) of adjacent discrete magnetic elements, and wherein S may be the same for both the first and second stators. Each discrete magnetic element may have a dimension D (e.g., width) in the direction of the axis, wherein D may be the same for all discrete magnetic elements on both the first and second stators. Gaps (e.g., recesses) may exist between adjacent discrete magnetic elements, wherein each gap may have a dimension G (e.g., width) in the direction of the axis, wherein G may be the same for all gaps on both the first and second stators. Therefore, the distance S between corresponding points (e.g., center points) of adjacent discrete magnetic elements may be S = D + G.

[0045] As mentioned above, the discrete magnetic element on the first stator is displaced relative to the discrete magnetic element on the second stator in the direction of the axis. The discrete magnetic element on the first stator may be displaced a distance X relative to the discrete magnetic element on the second stator along the axis (e.g., toward the second position), wherein X may be less than 50% of S, for example less than 40% of S; equal to 50% of S; or greater than 50% of S, for example greater than 60% of S. X may be between 25% and 75% of S, for example between 40% and 60% of S, or for example between 30% and 40% of S, or for example between 60% and 70% of S.

[0046] The frictionless safety brake actuator may also include a guide arrangement extending along or parallel to the axis, wherein the guide arrangement may be configured to constrain the magnet array to prevent movement transverse to (i.e., not parallel to) the axis. The magnet array may thus be restricted to movement along the axis.

[0047] The guide arrangement may include a guide element, such as a rod, extending through a hole that extends along or parallel to the axis through the magnet array. The guide arrangement may include one or more protruding tracks with corresponding slots (e.g., a slot on the magnet array and a track on the wall of a frictionless safety brake actuator, or vice versa), wherein the tracks and slots are parallel to the axis. Other guide arrangements are possible.

[0048] The biasing arrangement may include a resilient biasing member, such as a spring, or be composed of resilient biasing members. Other biasing arrangements are possible, and some non-limiting examples of other possible biasing arrangements include magnetic biasing arrangements, hydraulic biasing arrangements, pneumatic springs, rubber springs, helical springs, and bent metal sheets. The biasing arrangement may be configured to apply a biasing force by pushing or pulling the magnet array; for example, the biasing arrangement may include or be composed of a resilient biasing member arranged such that it is under tension when the magnet array is in a second position, or under compression when the magnet array is in a second position.

[0049] Each of the electromagnets(s) in the first magnet group may include a corresponding coil having a corresponding coil axis corresponding to the orientation of the electromagnet. In an example where there are two or more electromagnets in the first magnet group, the coils of the electromagnets in the first magnet group (or, in an example where there are more than two electromagnets in the first magnet group, the coils of the alternating electromagnets in the stacked first magnet group) may be wound in opposite directions, for example, such that currents flowing in the same direction along the two (or all) electromagnets produce different (or alternating) electromagnet orientations due to the different (or alternating) coil winding directions. This simplifies the electrical connections of the electromagnets in the magnet array.

[0050] As discussed above, when alternating current is applied to the electromagnet(s) in the first magnet group in use, the magnetic field of the magnet array can cause the magnet array to be attracted to the discrete magnetic elements of the stator facing the side of the magnet array with the strongest magnetic field region. Specifically, the magnet array can be attracted to one or more discrete magnetic elements whose positions along the axis are closer to the second position than the magnet array itself. This attraction can cause the magnet array to move against bias forces along the axis toward the second position, in order to move closer to the discrete magnetic elements(s) it has attracted. When the current changes direction, the magnet array is attracted to discrete magnetic elements on another stator. Again, the magnet array can be attracted to one or more discrete magnetic elements whose positions along the axis are closer to the second position than the magnet array itself. This attraction can cause the magnet array to move further along the axis toward the second position, in order to move closer to the discrete magnetic elements(s) it has attracted. As the magnet array moves along the axis toward the discrete magnetic elements(s) on one stator, its momentum helps to propel it forward along the axis. This helps to bring the magnet array closer to the next nearest discrete magnetic elements(s) on the other stator, thus facilitating the attraction of the next nearest discrete magnetic elements(s) when the current changes direction. This process can continue as the magnetic field alternates until the magnet array reaches a second position.

[0051] Alternating current can have any suitable frequency, for example, the frequency of alternating current can be in the range of 40Hz to 70Hz, such as 50Hz to 60Hz, 50Hz or 60Hz.

[0052] The magnet array may include multiple protrusions. One or more magnets in one of the first and second magnet groups may include protrusions. In an example where one or more magnets in one of the first and second magnet groups are oriented perpendicular to the axis, the magnet group including protrusions may be a group of magnets whose magnets are oriented perpendicular to the axis. Each magnet in the magnet group including protrusions may include one or more protrusions facing the first stator and one or more protrusions facing the second stator.

[0053] Each electromagnet in the first magnet group may include a core made of magnetic material, such as an iron core. Each electromagnet in the first magnet group (e.g., as part of its core) may include one or more protrusions corresponding to discrete magnetic elements on the first and second stators, such as one or more protrusions facing the first stator and one or more protrusions facing the second stator.

[0054] Each magnet in the second magnet group may include one or more protrusions corresponding to discrete magnetic elements on the first and second stators, such as one or more protrusions facing the first stator and one or more protrusions facing the second stator.

[0055] During the application of alternating current to the electromagnets(s) in the first magnet group, as the magnet array moves toward the second position, the protrusions may be arranged to alternately align with one or more discrete magnetic elements on the first stator and with one or more discrete magnetic elements on the second stator. The protrusions help direct the magnetic flux of the magnet array toward the discrete magnetic elements, enhance the attraction between the magnet array and the discrete magnetic elements, and help resist the biasing forces of the biased arrangement as it moves the magnet array along the axis.

[0056] In some examples where the magnet array includes protrusions, when the magnet array is in a first position, one or more protrusions on one side of the magnet array (e.g., on the first side or the second side) may partially overlap with one or more corresponding protrusions on the corresponding stator (e.g., on the first stator or the second stator, respectively). This helps to attract the magnet array to the protrusions on the corresponding stator when an alternating current is applied to the electromagnet(s) in the first magnet group. For example, overlap can help to accelerate the magnet array from a rest state in the first position, resisting the biasing force of the bias arrangement.

[0057] Due to the attraction between the overlapping protrusions on the magnet array and the stator, the magnet array can move in the direction of the second position, such that the protrusion(s) on the magnet array facing the corresponding stator can become aligned with the corresponding protrusion(s) on the stator. Due to the movement of the magnet array in the direction of the second position, the protrusion(s) on the magnet array facing the other of the first and second stators can become partially overlapping with the corresponding protrusion(s) on the other stator. As the magnet array moves in the direction of the second position, its momentum can help move it into the partially overlapping position. In some examples, the protrusion on the other stator can be displaced along the axis toward the second position by a distance less than 50% of S, which can help create partial overlap. This can be advantageous, for example, when an alternating current is initially applied to the electromagnet(s), because at this time the magnet array may not yet have sufficient momentum to move it toward the overlapping position.

[0058] Frictionless safety brake actuators or elevator systems may be configured to interrupt the application of alternating current and apply direct current to the electromagnets(s) in the first magnet group after the magnet array has reached the second position (e.g., immediately after the magnet array has reached the second position or after a subsequent delay).

[0059] The method may include interrupting the alternating current and applying direct current to the electromagnet(s) in the first group of magnets after the magnet array has reached the second position (e.g., immediately after the magnet array has reached the second position or after a subsequent delay).

[0060] In one set of examples, a frictionless safety brake actuator may include a limit switch arranged to detect when the magnet array has reached a second position. The frictionless safety brake actuator or elevator system may be configured to interrupt the application of alternating current and apply direct current to the electromagnet(s) in the first magnet group in response to the limit switch detecting that the magnet array has reached the second position.

[0061] A method for resetting a frictionless safety brake actuator may include detecting, via a limit switch, that the magnet array has reached a second position. The method may include receiving a signal from the limit switch indicating that the magnet array has reached the second position. The method may include interrupting alternating current and applying direct current to the electromagnet(s) in a first magnet group in response to the limit switch detecting that the magnet array has reached the second position (e.g., in response to receiving a limit switch signal).

[0062] When the magnet array is detected to have reached the second position, the alternating current can be interrupted without delay, for example, immediately. When the magnet array is detected to have reached the second position, direct current can be applied without delay, for example, immediately.

[0063] When the alternating current is interrupted, the magnetic field no longer alternates between the first and second sides of the magnet array, and therefore the magnet array stops moving along the axis. Instead, direct current can create a constant magnetic field on one side of the magnet array, causing the magnet array to remain attracted to the discrete magnetic elements on that side of the array, thereby holding the magnetic array in the second position. The direction of the direct current can be selected such that the magnetic field is strongest on one side of the magnet array where the (multiple) protrusions on the magnet array are aligned with the (multiple) discrete magnetic elements(s). The application of direct current can be maintained to hold the magnet array in the second position until the safety brake needs to be activated again.

[0064] In one set of examples, a frictionless safety brake actuator may include a stop arrangement positioned to prevent the magnet array from moving along the axis beyond a second position. For example, the stop arrangement may include a plate or block positioned on the axis; for instance, the stop arrangement may include the base, wall, or top plate of the frictionless safety brake actuator.

[0065] The stop arrangement can be positioned such that when the magnet array reaches the second position, the magnet array abuts against the stop arrangement. The normal reaction force of the stop arrangement can be opposite to any component of the magnetic force on the magnet array along the axis, the magnetic force being generated by the attraction of the magnet array to the discrete magnetic elements.

[0066] When the magnet array is in the second position, the continuous application of alternating current causes the magnet array to continue to be alternately attracted to the discrete magnetic elements on each stator. This resists the biasing force of the bias arrangement, holding the magnet array in the second position.

[0067] The stop arrangement may be magnetic. For example, the stop arrangement may include a ferromagnetic material, such as iron, and / or it may include a permanent magnet. This helps to hold the magnet array in a second position when alternating current is applied.

[0068] The stop arrangement may include discrete magnetic elements (e.g., protrusions of magnetic material or permanent magnets) facing the magnetic array. The magnetic array may have protrusions (e.g., protruding portions of magnets or cores of electromagnets facing the stop arrangement) corresponding to the discrete magnetic elements of the stop arrangement, which are positioned to align with the discrete magnetic elements of the stop arrangement when the magnetic array is in the second position. The protrusions help guide the magnetic flux of the magnet array to help the magnet array attract the stop arrangement, thereby holding the magnet array in the second position.

[0069] When the magnet array is in the second position, the continuous application of alternating current can cause the magnet array to be attracted to the stop arrangement, for example, to the alternating side of the stop arrangement. This attraction can resist the biasing force of the bias arrangement and hold the magnet array in the second position.

[0070] After the magnet array reaches the second position, the alternating current can be maintained until the safety brake needs to be activated again.

[0071] Alternatively, after the magnetic array reaches the second position, the alternating current can be interrupted, and direct current can be applied instead to the electromagnets(s) in the first magnet group. The direct current can create a constant magnetic field on one side of the magnet array, such that the magnet array remains attracted to the discrete magnetic elements on said side of the array and / or attracted to the stop arrangement (e.g., attracted to its discrete magnetic elements), thereby holding the magnetic array in the second position. The direction of the direct current can be selected such that the magnetic field is strongest on one side of the magnet array where the protrusions on the magnet array align with the discrete magnetic elements of the corresponding stator. After the magnet array reaches the second position, the application of direct current can be maintained until the safety brake needs to be activated again.

[0072] Although both alternating current and direct current can effectively hold the magnet array in the second position, using direct current for this purpose may be more energy-efficient than using alternating current.

[0073] Since alternating current (AC) can hold the magnet array in the second position, there is no need to switch from AC to DC at a precise or specific time corresponding to the magnet array reaching the second position, for example, in response to a switch detecting that the magnet array has reached the second position. For example, the current can switch from AC to DC at a predetermined time after the start of AC, which can be after a delay after the magnet array has reached the second position.

[0074] As noted above, the application of direct current or alternating current can be maintained to hold the magnet array in the second position until the safety brake needs to be activated again. When the safety brake needs to be activated, the direct current or alternating current applied to the electromagnet(s) in the first magnet group can be interrupted. In an example where the second magnet group includes one or more electromagnets (e.g., to which direct current is applied), the current to one or more electromagnets in the second magnet group can also be interrupted when the safety brake needs to be activated. The interruption of the current to the electromagnet(s) in the first magnet group (and optionally, if present, to any electromagnet in the second magnet group) can occur in response to a signal to activate the safety brake, or it can occur if the power supply to the frictionless safety brake actuator is disconnected (e.g., in the event of a power failure).

[0075] When the DC or AC power is interrupted, there is insufficient attraction between the magnet array and the stator (and / or, where applicable, between the magnet array and the stop arrangement) to hold the magnet array against the biasing force of the bias arrangement. Therefore, the magnet array moves from the second position to the first position under the influence of the biasing force. This movement of the magnet array applies a force to the linkage, actuating it. This force is transmitted from the linkage to the safety brake, causing the safety brake to engage frictionally with the guide rail.

[0076] Frictionless safety brake actuators can be configured or can be configured to be electronically or electrically actuated, for example, by a controller providing an actuation signal to the frictionless safety brake actuator and / or interrupting the electrical power supply to the frictionless safety brake actuator. Such frictionless safety brake actuators can be called "frictionless electronic safety actuators".

[0077] The frictionless safety brake actuator may include a controller. The frictionless safety brake actuator may be controlled by a controller external to the frictionless safety brake actuator. For example, an elevator system may include a controller, which may be mounted in or on the elevator car. The controller may be configured to receive signals, such as a reset signal or a signal from a limit switch. The controller may control multiple currents applied to (multiple) electromagnets in a first magnet group (and optionally, if present, any electromagnets in a second magnet group), for example, the controller may apply, change, or interrupt the multiple currents applied to (multiple) electromagnets. The controller may control the multiple currents in response to a signal (e.g., a reset signal or a signal from a limit switch). Attached Figure Description

[0078] Some preferred embodiments of this disclosure will now be described by way of example only, with reference to the accompanying drawings, in which:

[0079] Figure 1An example of an elevator system employing a mechanical speed controller is shown;

[0080] Figure 2 An example of an elevator system employing an electronically actuated frictionless safety brake actuator is shown;

[0081] Figure 3 A side view of a first example of a frictionless safety brake actuator according to this disclosure is shown;

[0082] Figure 4A A first example of a magnet array is shown with a positive current applied.

[0083] Figure 4B A voltage-time graph representing one cycle of alternating current is shown, indicating the portion of the cycle corresponding to the forward current;

[0084] Figure 4C A first example of a magnet array is shown with a reverse current applied;

[0085] Figure 4D A voltage-time graph representing one cycle of alternating current is shown, indicating the portion of the cycle corresponding to the reverse current;

[0086] Figures 5A to 5C A series of side views of a frictionless safety brake actuator of a first example are shown when the magnet array moves from a first actuated position toward a second unactuated position under the condition that an alternating current is applied to the magnet array.

[0087] Figure 5D A side view of a first example of a frictionless safety brake actuator that is held in a second position by applying direct current to a magnet array is shown.

[0088] Figure 5E This shows a voltage-time graph representing a portion of the alternating current cycle before the application of direct current;

[0089] Figure 6 A side view of a frictionless safety brake actuator, a first example, is shown during the actuation process.

[0090] Figure 7A A side view of a second example of a frictionless safety brake actuator according to the present disclosure is shown, wherein the frictionless safety brake actuator is in an actuated state; and

[0091] Figure 7B A side view of a second example of a frictionless safety brake actuator in an unactuated state is shown. Detailed Implementation

[0092] Figure 1An elevator system, generally indicated by 10, is shown. Elevator system 10 includes a cable or belt 12, a car frame 14, an elevator car 16, roller guides 18, guide rails 20, a speed controller 22, and a pair of safety brakes 24 mounted on the elevator car 16. The speed controller 22 is mechanically connected via a linkage 26, a lever 28, and a lifting rod 30 to actuate the safety brakes 24. The speed controller 22 includes a speed controller pulley 32, a rope loop 34, and a tension pulley 36. The cable 12 is connected to the car frame 14 and a counterweight (not shown) inside the hoistway. The elevator car 16, attached to the car frame 14, moves upward and downward along the hoistway by forces transmitted to the car frame 14 via the cable or belt 12 by an elevator drive (not shown) located in a machine room typically at the top of the hoistway. The roller guides 18 are attached to the car frame 14 to guide the elevator car 16 upward and downward along the guide rails 20. The governor pulley 32 is mounted at the upper end of the shaft. A rope loop 34 partially wraps around the governor pulley 32 and partially around the tension pulley 36 (located at the bottom of the shaft in this example). The rope loop 34 is also connected to the elevator car 16 at the rod 28, ensuring that the angular velocity of the governor pulley 32 is directly related to the speed of the elevator car 16.

[0093] exist Figure 1 In the elevator system 10 shown, when the elevator car 16 travels inside the hoistway, if it exceeds a set speed, the governor 22, the machine brake (not shown) located in the machine room, and the safety brake 24 activate to stop the elevator car 16. If the elevator car 16 reaches an overspeed condition, the governor 22 is initially triggered to engage a switch, which in turn cuts off power to the elevator drive and causes the machine brake to drop to prevent movement of the drive pulley (not shown), and thus to stop the elevator car 16 from moving. However, if the elevator car 16 continues to experience an overspeed condition, the governor 22 may subsequently activate to trigger the safety brake 24 to stop the elevator car 16 from moving (i.e., an emergency stop). In addition to engaging the switch to drop the machine brake, the governor 22 also releases a clutch that holds the governor rope 34. The governor rope 34 is connected to the safety brake 24 via a mechanical linkage 26, a lever 28, and a lifting rod 30. As the elevator car 16 continues its descent, the now-activated governor 22 stops the movement of the governor rope 34, which pulls the operating lever 28. The operating lever 28 actuates the safety brake 24 by moving the linkage 26 connected to the lifting rod 30, and the lifting rod 30 causes the safety brake 24 to engage the guide rail 20, thus stopping the elevator car 16.

[0094] It will be appreciated that although a corded elevator is described herein, the example of the frictionless safety brake actuator described herein will work just as well with cordless elevator systems (e.g., hydraulic systems, systems with linear motors, and other cordless elevator designs).

[0095] While mechanical governor systems are still used in many elevator systems, other systems (e.g., cordless elevator systems without mechanical governors) are now implementing electronic or electrical actuation systems to trigger the emergency safety brake 24. Most of these electronic or electrical actuation systems use friction between a magnet and the guide rail 20 to mechanically actuate the linkage to engage the safety brake 24. An example of a safety brake actuator is disclosed herein that does not utilize friction against the guide rail 20 to actuate the safety brake 24.

[0096] Figure 2 An example of an elevator system 50 employing an electronically actuated frictionless safety brake actuator 52 is shown. The elevator system 50 includes the frictionless safety brake actuator 52, an elevator car 54, two guide rails 56, a safety brake 58, and a controller 60. For clarity, one of the guide rails 56 is shown in dashed outline, and the other guide rail... Figure 2 omitted.

[0097] The elevator car 54 includes a platform 62, a top plate 64, a first structural member 66, and a second structural member 68. The first structural member 66 and the second structural member 68 may be referred to as "columns". The elevator car 54 also includes panels forming the walls of the elevator car 54 and other components, but for clarity, they will be referred to as such from... Figure 2 These panels and other components are omitted from the text.

[0098] Frictionless safety brake actuator 52 and safety brake 58 are mounted on the first structural member 66. Frictionless safety brake actuator 52 is mechanically connected to safety brake 58 via linkage 70. Second safety brake actuator and second safety brake are disposed on the second structural member, but are omitted for clarity. Controller 60 is mounted in top plate 64 and communicates with frictionless safety brake actuator 52 via connector 72.

[0099] The safety brake 58 has a slot 76 for receiving the guide rail 56. A frictionless safety brake actuator 52 is positioned above the safety brake and adjacent to the guide rail 56, although other positions are possible; for example, the frictionless safety brake actuator 52 may be positioned away from the guide rail 56 because it does not require frictional contact with the guide rail 56 during operation. In use, the elevator car 54 moves up and down along the guide rail 56. When it is necessary to engage the safety brake 58 (e.g., in case of elevator car overspeed), the controller 60 sends a signal to the frictionless safety brake actuator 52 to engage the safety brake 58. In response to this signal, the actuation mechanism in the frictionless safety brake actuator 52 applies a pulling force to the linkage 70. The pulling force is transmitted via the linkage 70 to the safety brake 58, pulling the safety brake 58 into frictional engagement with the guide rail 56, thus stopping the elevator car 54.

[0100] Frictionless safety brake actuator 52 may, for example, be according to the following reference Figure 3 , Figures 5A to 5D , Figure 6 and Figures 7A to 7B The example described is one of the frictionless safety brake actuators used for operation.

[0101] In the following description of an example of a frictionless safety brake actuator, the terms “left,” “right,” “up,” “down,” “above,” “below,” and similar positional and directional terms are used to refer to certain depicted features. When viewed in the accompanying drawings, these terms are used purely for convenience in referring to the position or orientation of these features and do not necessarily imply any claim to the position or orientation of those features in the frictionless safety brake actuator according to this disclosure.

[0102] Figure 3 A side view of a first example of a frictionless safety brake actuator 100 according to this disclosure is shown.

[0103] The frictionless safety brake actuator 100 includes a magnet array 102 positioned between a left stator 104 and a right stator 106. The frictionless safety brake actuator 100 also includes a linkage 108, which is attached at a first end to a connection point 110 on the magnet array 102. A second end of the linkage 108 is attached to the safety brake (…). Figure 3 Not shown in the image, but refer to the image below. Figure 6 (Description and discussion) such that when the linkage 108 is pulled upward, the safety brake engages, and when the linkage 108 is pushed downward, the safety brake disengages.

[0104] The frictionless safety brake actuator 100 also includes a base 112 and a guide element 114, with stators 104, 106 mounted on the base 112. The guide element 114 extends vertically upward from the base 112 along an axis 115 between the stators 104, 106. In this example, the guide element is a rod, but other types of guide elements are also possible. The magnet array 102 is movable along the guide element 114 between a first position in which the linkage 108 is actuated and a second position in which the linkage 108 is not actuated. Figure 3 The magnet array 102 is shown in a first (actuated) position. The guide element 114 restricts the movement of the magnet array 102 in the vertical direction, for example, preventing any non-vertical component of the movement of the magnet array 102.

[0105] The frictionless safety brake actuator 100 also includes a biasing arrangement that applies an upward biasing force (as indicated by arrow 116) to bias the magnet array 102 toward a first position. In this example, the biasing arrangement is a spring 118, although other biasing arrangements, such as magnetic biasing arrangements, hydraulic biasing arrangements, pneumatic springs, rubber springs, helical springs, bent metal sheets, etc., may be used in this and other examples. A first end 120 of the spring 118 is fixedly attached to the magnet array 102, and a second end 122 of the spring 118 is fixedly attached to the base 112.

[0106] The frictionless safety brake actuator 100 also includes a limit switch 124, which is configured to detect when the frictionless safety brake actuator 100 has reached the second position. (See below for further details.) Figure 5D The function of limit switch 124 is described in more detail.

[0107] In this example, stators 104 and 106 are made of iron, and each stator 104 and 106 includes an array of teeth 126 and 128 projecting horizontally inward (i.e., toward the magnet array 102) between stators 104 and 106. The teeth 126 and 128 on each stator 104 and 106 are separated by a spacing S. The teeth 128 on the right stator 106 are vertically displaced downward relative to the teeth 126 on the left stator 104 by a displacement X, which is less than half the spacing S. In this example, the displacement X is approximately 25% of the spacing S. However, these stators are merely examples, and other stator structures and tooth arrangements are possible in variations of this example and others.

[0108] The magnet array 102 includes an upper electromagnet 130 and a lower electromagnet 132, with a permanent magnet 134 positioned between them. The upper electromagnet 130 and lower electromagnet 132 together correspond to a first magnet group, and the permanent magnet corresponds to a second magnet group. As indicated by arrow 136, the permanent magnet 134 is vertically oriented with its north pole pointing downwards. Each of the upper electromagnet 130 and lower electromagnet 132 includes a corresponding coil 138, 140 wound around a corresponding iron core 142, 144.

[0109] The cores 142 and 144 of each electromagnet 130, 132 are shaped to have a left protrusion 146 and a right protrusion 148 extending toward the left stator 104 and the right stator 106, respectively. The protrusions 146 and 148 are positioned such that they align with and closely approach the teeth 126 and 128 on the stators 104 and 106 as the magnet array 102 moves upward and downward along the guide element 114. The protrusions 146 and 148 help guide magnetic flux from the cores 142 and 144 toward the stator teeth 126 and 128.

[0110] The coils 138 and 140 of electromagnets 130 and 132 are configured to be supplied with a current that can be changed between alternating current and direct current. When current is supplied to electromagnets 130 and 132, the same current is supplied to both electromagnets 130 and 132 at any given time. Electromagnets 130 and 132 and their coils 138 and 140 are configured such that when current is supplied to electromagnets 130 and 132, the direction of the magnetic flux in coils 138 and 140 is directed to the left for one coil and to the right for the other coil, for example, antiparallel to each other and perpendicular to the orientation of the permanent magnet. When the current changes direction, the magnetic orientation of the two electromagnets 130 and 132 is reversed.

[0111] This particular configuration of magnet array 102 is merely one example. In other examples, the permanent magnets may point upwards. In other examples, the magnet array may include an electromagnet positioned between two permanent magnets, wherein the permanent magnets are oriented antiparallel and point left and right, while the electromagnet is vertically oriented and alternates between pointing upwards and downwards when alternating current is applied to it. Other configurations of the magnet array are possible in variations of this example and in other examples. For example, more than three magnets may be present in total. Electromagnets supplied with direct current may be used instead of permanent magnets.

[0112] The following reference Figures 4A to 4D Describe the function of magnet array 102.

[0113] Figure 4A The magnet array 102 is shown during the application of a positive current to the electromagnets 130, 132 (e.g., during the first half of an alternating current cycle). Figure 4BA graph 150 shows the voltage change over time for one cycle of alternating current (151). The thick line 152 shows the portion of the cycle where the current is in the positive direction, i.e., this portion corresponds to... Figure 4A The situation described in the text.

[0114] Refer again Figure 4A A forward current generates a magnetic field within and around each electromagnet 130, 132, wherein the upper electromagnet 130 is magnetically oriented to the right (as indicated by arrow 154), and the lower electromagnet 132 is magnetically oriented to the left (as indicated by arrow 156). As mentioned above, the permanent magnet 134 is magnetically oriented downwards (as indicated by arrow 136).

[0115] As those skilled in the art will understand, this arrangement of magnetic orientations (which is an example of a Hellbeck array) will produce a composite magnetic field extending to the left side of the magnet array 102, as indicated by the magnetic flux line 158, while the magnetic field to the right side of the magnet array 102 is suppressed to near zero.

[0116] Figure 4C The magnet array 102 is shown during the application of reverse current to the electromagnets 130, 132 (e.g., during the latter half of an alternating current cycle). Figure 4D A graph 160 shows the voltage versus time for one cycle of alternating current (151), with thick lines 162 indicating the portion of the cycle where the current is in the opposite direction, i.e., this portion corresponds to... Figure 4C The situation described in the text.

[0117] Refer again Figure 4C The reverse current generates a magnetic field within and around each electromagnet 130, 132. The upper electromagnet 130 is magnetically oriented to the left (as shown by arrow 164), and the lower electromagnet 132 is magnetically oriented to the right (as shown by arrow 166). That is, the electromagnet orientations are... Figure 4A In contrast, the magnetic orientation of permanent magnet 134 is downward (as indicated by arrow 136), that is, opposite to... Figure 4A The comparison remains unchanged.

[0118] This arrangement of magnetic orientation will generate a composite magnetic field extending to the right side of the magnet array 102, as shown by the magnetic flux line 168, while the magnetic field to the left side of the magnet array 102 is suppressed to near zero.

[0119] Therefore, from Figures 4A to 4D It will be understood that when alternating current is applied to electromagnets 130 and 132, magnet array 102 will generate magnetic fields that alternately extend to the left and right sides of magnet array 102.

[0120] Figures 5A to 5EThis illustrates how the alternating field generated by the magnet array 102 during the application of alternating current is used to reset the frictionless safety brake actuator 100 from a first position to a second position.

[0121] Figure 5A The frictionless safety brake actuator 100 is shown in the first position (i.e., the position where the linkage 108 is actuated to engage the safety brake). To reset the frictionless safety brake actuator 100, alternating current is applied to the electromagnets 130 and 132.

[0122] Figure 5A The diagram illustrates the time points during the first half of the first cycle of the alternating current (i.e., when the current is in the positive direction). See above for reference. Figures 4A to 4D During the application of a positive current to electromagnets 130 and 132, each electromagnet generates a magnetic field, with the upper electromagnet 130 oriented to the right (as indicated by arrow 154) and the lower electromagnet 132 oriented to the left (as indicated by arrow 156). This produces a combined magnetic field extending to the left side of the magnet array 102. The combined magnetic field causes magnetic attraction between the magnet array 102 and the teeth 126 of the left stator 104.

[0123] As from Figure 5A As can be seen, in the first position, the left protrusion 146 on the electromagnet cores 142 and 144 partially overlaps with two of the teeth 126a and 126b on the left stator 104. The teeth 126a and 126b are slightly lower than the left protrusion 146 on the cores 142 and 144. Therefore, the attraction between the electromagnets 130 and 132 and the stator teeth 126a and 126b results in downward and leftward forces on the magnet array, as indicated by arrow 170.

[0124] Because the guiding element 114 prevents any non-vertical movement of the magnet array 102, the effect of this force is that the magnet array 102 moves downward against the biasing force of the spring 118. This causes the magnet array 102 to... Figure 5B The position shown has been moved.

[0125] As in Figure 5B As can be seen, the downward movement of the magnet array 102 has aligned the left protrusion 146 on the cores 142 and 144 with the two stator teeth 126a and 126b. The magnet array 102 has also moved relative to the right stator 106. As mentioned above, the teeth 128 of the right stator 106 have been vertically displaced downward by a displacement distance X, which is approximately 25% of the spacing distance S between the stator teeth. Therefore, when the left protrusion 146 on the cores 142 and 144 is aligned with the left stator tooth 126, the right protrusion 148 on the cores 142 and 144 partially overlaps with the teeth 128a and 128b on the right stator 106.

[0126] As mentioned above, the displacement distance X of the right stator tooth 128 relative to the left stator tooth 126 need not be less than 50% of the spacing distance S. For example, the displacement distance X can be 50% or greater than 50% of the spacing distance S. The momentum associated with the downward movement of the magnet array 102 can propel the magnet array 102 past the point where the left core protrusion 146 overlaps with the left stator tooth 126, such that the right core protrusion 148 overlaps with the right stator tooth 128, even in examples where the displacement distance X is not less than 50% of the spacing distance S.

[0127] However, as mentioned above, in this example, the displacement distance X is less than 50% of S. This helps to ensure that the right core protrusion 148 overlaps with the right stator tooth 128 at least somewhat, even if the magnet array 102 may not have enough momentum to propel it past the point where the left protrusion 146 aligns with the left stator tooth 126 (e.g., because the magnet array 102 may be accelerated from a stationary state in the first position).

[0128] In the direction of magnet array 102 Figure 5B During the movement of the position shown, the alternating current changes direction. Figure 5B The diagram illustrates the moment during the latter half of the first cycle of the alternating current (i.e., when the current is in the reverse direction). The magnetic orientations of electromagnets 130 and 132 are reversed, such that the upper electromagnet is oriented to the left (as indicated by arrow 164), and the lower electromagnet is oriented to the right (as indicated by arrow 166). See reference... Figure 4C and Figure 4D As discussed, this generates a composite magnetic field extending to the right side of the magnet array 102. The composite magnetic field causes magnetic attraction between the teeth 128 of the right stator 106 and the electromagnets 130, 132.

[0129] As mentioned, in Figure 5B In the positions shown, the right protrusion 148 on the electromagnet cores 142 and 144 partially overlaps with two of the teeth 128a and 128b on the right stator 106, and the teeth 128a and 128b are slightly lower than the right protrusion 148 on the cores 142 and 144. Therefore, the attraction between the electromagnets 130 and 132 and the stator teeth 128a and 128b results in downward and rightward forces acting on the magnet array, as indicated by arrow 176.

[0130] Because the guiding element 114 prevents any non-vertical movement of the magnet array 102, the force causes the magnet array 102 to continue moving downwards against the biasing force of the spring 118. This causes the magnet array 102 to... Figure 5C The position shown has been moved.

[0131] As from Figure 5CAs can be seen, the momentum of the magnet array 102 has propelled it past the point where the right core protrusion 148 overlaps with the right stator teeth 128a and 128b, and the magnet array 102 has reached the position where the left core protrusion 146 has begun to overlap with the next pair of left stator teeth 126b and 126c.

[0132] The magnet array 102 is currently... Figure 5B Move the position in the middle to Figure 5C During the time it takes for the current to change direction again, at the position in the middle, the current changes direction again. Therefore, Figure 5C The diagram illustrates the time points during the first half of the second cycle of the alternating current. (Refer to the above.) Figure 5A In the same manner described, the synthetic magnetic field extends to the left side of the magnet array 102, creating an attraction (i.e., downward and to the left, as indicated by arrow 178) between the magnet array and the partially overlapping left stator teeth 126b, 126c. This allows the downward movement of the magnet array 102 to continue.

[0133] The downward movement of the magnet array 102 continues until it reaches the second position, at which point it triggers the limit switch 124, as... Figure 5D As shown in the figure. For illustrative purposes, the limit switch 124 is depicted in the figures as a simple mechanical switch, but it should be understood that any suitable switch (e.g., mechanical, electronic, magnetic, optical, etc.) can be used. It should also be understood that, for clarity, the frictionless safety brake actuator is shown in the depicted example as having only a few stator teeth between the first and second positions, but in actual implementations, more teeth are typically present between the first and second positions.

[0134] Actuation of limit switch 124 causes a signal to be sent to the controller (e.g., as shown in the image). Figure 2 As shown in the diagram, this indicates that the second position has been reached. In response to this signal, the controller interrupts the AC power and instead applies DC power to the electromagnets 130 and 132. Figure 5E The diagram illustrates this change in electric current.

[0135] Figure 5E A coordinate diagram 180 shows a portion of the cycle of alternating current supplied to electromagnets 130, 132 as the magnet array 102 approaches the second position. Midway through the latter half of the cycle, limit switch 124 is triggered, and the alternating current is replaced by direct current (i.e., a constant voltage as shown by thick line 182).

[0136] In this example, the direct current is in the reverse current direction, causing the resultant magnetic field generated by the magnet array 102 to extend to the right. This creates an attractive force between the magnet array 102 and two of the right stator teeth 128 (indicated by arrow 184), which, when the magnet array 102 is in the second position, attract the two right stator teeth 128 (as from...). Figure 5D As can be seen in the image, it is aligned with the right core protrusion 148. This provides good attraction between the magnet array 102 and the right stator tooth 128, thereby resisting the biasing force of the spring 118 and holding the magnet array 102 in the second position.

[0137] As mentioned, the linkage 108 is attached to the magnet array 102, so when the magnet array 102 moves toward the second position, it pushes the linkage 108 back to its unacted position. Once the magnet array 102 has reached the second position, as... Figure 5D As illustrated, the linkage 108 is in its unacted position, and the safety brake has disengaged. Once direct current has been applied to hold the magnet array 102 in the second position, the reset of the frictionless safety brake actuator is complete, and it is ready to be actuated again when the safety brake needs to be applied.

[0138] Figure 6 It shows Figure 3 and Figures 5A to 5D The system includes a frictionless safety brake actuator 100 and a safety brake 186 connected to the frictionless safety brake actuator 100 via a linkage device 108. The frictionless safety brake actuator 100 is located near the guide rail 188 of the elevator system. The frictionless safety brake actuator 100 is positioned above the safety brake in a non-actuated position, so that the safety brake does not engage frictionally with the guide rail.

[0139] Figure 6 The illustration shows the actuation of the frictionless safety brake actuator 100 for pulling up to the linkage 108 and engaging the safety brake. Figure 6 In the second position, the frictionless safety brake actuator 100 is in the frictionless safety brake actuator position. To actuate the safety brake, the direct current to the electromagnets 130 and 132 is interrupted, i.e., the electromagnets 130 and 132 are turned off and do not generate a magnetic field. The permanent magnet 134 still has a magnetic field and a downward orientation as indicated by arrow 136. However, with the electromagnets 130 and 132 off, the combined magnetic field of the magnet array 102 is insufficient to resist the biasing force of the spring 118 and hold the magnet array 102 in the second position.

[0140] The magnet array 102 is pushed upward in the direction of arrow 190 by the biasing force of spring 118. The magnet array 102 moves upward to the first position (i.e., returns to the starting position). Figure 3 (The position is depicted in the image). As the magnet array 102 moves upward, as indicated by arrow 192, the magnet array 102 applies an upward pulling force to the linkage 108. This force is transmitted from the linkage 108 to the safety brake, pulling the safety brake upward to engage with the guide rail.

[0141] Figure 7A and Figure 7B A second example of a frictionless safety brake actuator 200 according to this disclosure is shown.

[0142] Figure 7A The frictionless safety brake actuator 200 in the first (actuated) position is shown. Except for the presence of a stop 202 at the bottom of the stators 104 and 106 and the absence of a limit switch, the frictionless safety brake actuator 200 has the same characteristics as... Figure 3 , Figures 5A to 5B and Figure 6 The example has the same structure (and therefore the same reference numerals are used to label the corresponding features). The stop 202 is made of magnetic material and has two upward-protruding teeth (left tooth 204 and right tooth 206). In addition, the core 144 of the lower electromagnet 132 has two downward-protruding protrusions 208.

[0143] To reset the frictionless safety brake actuator 200 (i.e., to move the magnet array 102 from the first position to the second position), an alternating current is applied to the electromagnets 130 and 132. Regarding the manner in which the magnet array 102 moves downward by applying the alternating current, the frictionless safety brake actuator 200 is in conjunction with... Figure 3 , Figures 5A to 5B and Figure 6 The example operates in the same manner (and therefore the description of that operation will not be repeated). However, the way the frictionless safety brake actuator 200 stops the movement of the magnet array 102 and holds the magnet array 102 in the second position is different, and is described below.

[0144] When the frictionless safety brake actuator 200 reaches the second position, such as Figure 7B As shown, the lower protrusion 208 on the lower electromagnet 132 abuts against the teeth 204, 206 on the stop 202. This prevents the magnet array 102 from moving further downward, even when an alternating current is continuously applied.

[0145] While alternating current is still applied, the combined magnetic field continues to alternately move left and right, alternately attracting teeth 126 of the left stator 104 and teeth 128 of the right stator 106. Furthermore, since the stop 202 is magnetic, the magnet array 102 also alternately attracts the left teeth 204 and right teeth 206. (As from...) Figure 7BAs can be seen, when the magnet array 102 is in the second position, the lower protrusion 208 on the magnet array 102 and the teeth 204, 206 on the stop 202 are aligned. This helps to guide the magnetic flux toward the teeth 204, 206 of the stop, thereby enhancing the magnetic attraction between the magnet array 102 and the stop 202. This attraction between the magnet array 102 and the teeth 126, 128 of the stator 104, 106 and the stop 202 resists the biasing force of the spring 118, holding the magnet array 102 in the second position.

[0146] Alternating current could be maintained to hold the magnet array 102 in the second position. However, in this example, after the magnet array 102 has reached the second position, the alternating current is interrupted, and instead, direct current is applied to the electromagnets 130, 132. This is more energy-efficient than maintaining alternating current to hold the magnet array 102 in the second position.

[0147] It is not important to switch from AC to DC at the exact moment the magnet array 102 reaches the second position, because the stop 202 prevents the magnet array 102 from moving too far downwards. Therefore, it is not important to detect the magnet array 102 reaching the second position, for example, using a limit switch, although a limit switch can still be provided. In this example, the current switches from AC to DC shortly after the magnet array 102 reaches the second position.

[0148] The direct current causes a combined magnetic field in the magnet array 102, which attracts the magnet array 102 to some of the teeth 126 of the left stator 104 and some of the left teeth 204 on the stop 202 (as indicated by arrow 208), holding the magnet array 102 in the second position against the biasing force of the spring 118 until the safety brake needs to be re-engaged.

[0149] exist Figure 3 , Figures 5A to 5D , Figure 6 and Figures 7A to 7B In the examples, the frictionless safety brake actuators 100 and 200 are positioned (or configured to be positioned) above the safety brake in each case, such that the safety brake is actuated by pulling upward on the magnet array 102 of the linkage 108. However, the frictionless safety brake actuator according to this disclosure can be used with a safety brake actuated by the linkage 108, which is pushed to engage the safety brake.

[0150] In the role of Figure 3 , Figures 5A to 5D , Figure 6 and Figures 7A to 7B In some example arrangements of variations of the example, a safety brake that can be actuated by pushing a linkage device is provided as in Figure 3 , Figures 5A to 5D , Figure 6and Figures 7A to 7B The safety brake actuator is depicted in the diagram. In the variant, it is... Figure 3 , Figures 5A to 5D , Figure 6 and Figures 7A to 7B Compared to the positions shown, the positions of the frictionless safety brake actuator and the safety brake are interchanged. The magnet array is connected to the linkage of the safety brake, such that when the magnet array moves upward under the biasing force of the spring, it pushes the linkage upward to engage the safety brake.

[0151] Those skilled in the art will recognize that this disclosure has been described by way of one or more specific aspects, but is not limited to these aspects; many variations and modifications are possible within the scope of the appended claims.

Claims

1. A frictionless safety brake actuator (100; 200) for use in an elevator system (50), comprising: At least two stators, comprising a first stator (104) and a second stator (106) extending in corresponding substantially parallel planes; A magnet array (102) is positioned between the first stator and the second stator (104, 106); A linkage device (108) actuated to move a safety brake (58; 186) into frictional engagement with elevator guide rails (56; 188), wherein the linkage device (108) is attached to the magnet array (102), and wherein the magnet array (102) is movable along an axis (115) extending substantially parallel to the first and second stators (104, 106) between a first position in which the linkage device (108) is actuated and a second position in which the linkage device (108) is not actuated; and A bias arrangement (118) is configured to apply a bias force to the magnet array (102) to bias the magnet array (102) toward the first position; The magnet array (102) includes a first magnet group and a second magnet group, wherein the first magnet group and the second magnet group each include at least one magnet and a total of at least three magnets, wherein the one or more magnets (130, 132) of the first magnet group and the one or more magnets (134) of the second magnet group are alternately arranged in a stack, wherein each magnet in the first magnet group is an electromagnet (130, 132), and wherein the magnet array (102) generates a magnetic field (158, 168). The one or more electromagnets (130, 132) in the first magnet group and the one or more magnets (134) in the second magnet group each have a corresponding orientation (154, 156, 134, 164, 166) such that when a forward current (152) is supplied to the one or more electromagnets (130, 132) in the first magnet group, the magnetic field (158) is stronger on a first side of the magnet array (102) adjacent to the first stator (104) than on a second opposite side of the magnet array (102) adjacent to the second stator (106), and when a reverse current (162) is supplied to the one or more electromagnets (130, 132) in the first magnet group, the magnetic field (168) is stronger on the second side of the magnet array (102) than on the first side of the magnet array (102); The first stator and the second stator (104, 106) each include a corresponding array of discrete magnetic elements (126, 128) extending parallel to the axis (115), wherein the discrete magnetic elements (126, 128) have an interleaved configuration in which the discrete magnetic elements (126, 128) on the first stator (104) are displaced relative to the discrete magnetic elements (126, 128) on the second stator (106) in the direction of the axis (115).

2. The frictionless safety brake actuator (100; 200) according to claim 1, wherein... The respective orientations (154, 156, 134, 164, 166) of the one or more electromagnets (130, 132) of the first magnet group and the one or more magnets (134) of the second magnet group are all located in a plane parallel to the axis (115) and perpendicular to the first stator and the second stator (104, 106). The first and second magnet groups comprise a total of N magnets arranged at N positions marked from n=1 to n=N along the axis (115), wherein, The one or more electromagnets (130, 132) of the first magnet group and the one or more magnets (134) of the second magnet group are oriented such that: when a forward current (152) is applied to the one or more electromagnets (130, 132) of the first magnet group, for n=1 to n=N-1, the (n+1)th magnet has an orientation that is rotated 90° relative to the orientation of the nth magnet in a first rotational direction, and when a reverse current (162) is applied to the one or more electromagnets (130, 132) of the first magnet group, for n=1 to n=N-1, the (n+1)th magnet has an orientation that is rotated 90° relative to the nth magnet in a second rotational direction opposite to the first rotational direction.

3. The frictionless safety brake actuator (100; 200) according to claim 1 or 2, wherein... i) The one or more electromagnets (130, 132) of the first magnet group are oriented perpendicular to the axis (115), and the one or more magnets (134) of the second magnet group are oriented parallel to the axis (115); or ii) The one or more electromagnets (130, 132) of the first magnet group are oriented parallel to the axis (115), and the one or more magnets (134) of the second magnet group are oriented perpendicular to the axis (115).

4. The frictionless safety brake actuator (100; 200) according to claim 1, 2, or 3, wherein, The magnet in the second magnet group, or each magnet, is a permanent magnet (134).

5. The frictionless safety brake actuator (100; 200) according to any one of the preceding claims, wherein, The first stator and the second stator (104, 106) are made of magnetic material, and wherein the array of discrete magnetic elements (126, 128) of the first stator and the second stator (104, 106) each includes a corresponding array of protrusions of magnetic material protruding from the respective stator (104, 106) toward the magnet array (102).

6. The frictionless safety brake actuator (100; 200) according to any one of the preceding claims, wherein, The discrete magnetic elements (126, 128) of the first stator and the second stator (104, 106) are uniformly spaced apart along the axis (115) at a distance S, wherein the distance S is measured between corresponding points of adjacent discrete magnetic elements (126, 128), and wherein S is the same for both the first stator and the second stator (104, 106).

7. The frictionless safety brake actuator (100; 200) according to claim 6, wherein, The discrete magnetic elements (126, 128) on the first stator (104) are displaced by a distance X along the axis (115) relative to the discrete magnetic elements (126, 128) on the second stator (106), wherein X is less than 50% of S, for example less than 40% of S.

8. The frictionless safety brake actuator (100; 200) according to any one of the preceding claims further includes a guide arrangement (114) extending along or parallel to said axis (115), wherein, The guide arrangement (114) is configured to constrain the magnet array (102) to prevent movement transverse to the axis (115).

9. The frictionless safety brake actuator (100; 200) according to any one of the preceding claims, wherein, The magnet array (102) includes a plurality of protrusions (146, 148) arranged to alternately align with one or more of the discrete magnetic elements (126, 128) on the first stator (104) and with one or more of the discrete magnetic elements (126, 128) on the second stator (106) as the magnet array (102) moves toward the second position during the application of alternating current (151) to one or more of the electromagnets (130, 132) in the first magnet group.

10. The frictionless safety brake actuator (100) according to any one of the preceding claims further includes a limit switch (124) arranged to detect when the magnet array (102) has reached the second position.

11. The frictionless safety brake actuator (200) according to any one of the preceding claims further includes a stop arrangement (202) positioned to prevent the magnet array (102) from moving along the axis (115) beyond the second position, wherein, The stop arrangement (202) is magnetic.

12. A method for resetting a frictionless safety brake actuator (100; 200) according to any one of the preceding claims, the method comprising: Alternating current (151) is applied to one or more electromagnets (130, 132) in the first magnet group until the magnet array (102) has moved to the second position.

13. The method of claim 12, further comprising interrupting the alternating current (151) and applying direct current (182) to the one or more electromagnets (130, 132) in the first magnet group after the magnet array (102) has reached the second position.

14. The method of claim 13, further comprising detecting, via a limit switch (124) / the limit switch (124), that the magnet array (102) has reached the second position, wherein, In response to the limit switch (124) detecting that the magnet array (102) has reached the second position, the alternating current (151) is interrupted and the direct current (182) is applied to the one or more electromagnets (130, 132) in the first magnet group.

15. An elevator system (50) comprising elevator guide rails, an elevator car, a frictionless safety brake actuator (100; 200), and a safety brake (58; 186), wherein, The frictionless safety brake actuator (100; 200) and the safety brake (58; 186) are mounted to the elevator car for movement along the guide rails during elevator car use; wherein the safety brake actuator (100; 200) comprises: At least two stators, comprising a first stator (104) and a second stator (106) extending in corresponding substantially parallel planes; A magnet array (102) is positioned between the first stator and the second stator (104, 106); A linkage device (108) actuated to move the safety brake (58; 186) into frictional engagement with the elevator guide rails, wherein the linkage device (108) is attached to the magnet array (102), and wherein the magnet array (102) is movable along an axis (115) extending substantially parallel to the first and second stators (104, 106) between a first position in which the linkage device (108) is actuated and a second position in which the linkage device (108) is not actuated; and A bias arrangement (118) is configured to apply a bias force to the magnet array (102) to bias the magnet array (102) toward the first position; The magnet array (102) includes a first magnet group and a second magnet group, wherein the first magnet group and the second magnet group each include at least one magnet and a total of at least three magnets, wherein the one or more magnets (130, 132) of the first magnet group and the one or more magnets (134) of the second magnet group are alternately arranged in a stack, wherein each magnet in the first group is an electromagnet (130, 132), and wherein the magnet array (102) generates a magnetic field (158, 168). The one or more electromagnets (130, 132) in the first magnet group and the one or more magnets (134) in the second magnet group each have a corresponding orientation (154, 156, 134, 164, 166) such that when a forward current (152) is supplied to the one or more electromagnets (130, 132) in the first magnet group, the magnetic field (158) is stronger on a first side of the magnet array (102) adjacent to the first stator (104) than on a second opposite side of the magnet array (102) adjacent to the second stator (106), and when a reverse current (162) is supplied to the one or more electromagnets (130, 132) in the first magnet group, the magnetic field (168) is stronger on the second side of the magnet array (102) than on the first side of the magnet array (102); The first stator and the second stator (104, 106) each include a corresponding array of discrete magnetic elements (126, 128) extending parallel to the axis (115), wherein the discrete magnetic elements (126, 128) have an interleaved configuration in which the discrete magnetic elements (126, 128) on the first stator (104) are displaced relative to the discrete magnetic elements (126, 128) on the second stator (106) in the direction of the axis (115).

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