Patent Description:
Many elevator systems include a hoisted elevator car, a counterweight, a tension member which connects the hoisted elevator car and the counterweight, and a sheave that contacts the tension member. During operation of such an elevator system, the sheave may be driven by a machine to move the elevator car and the counterweight through the hoistway, with their movement being guided by guide rails. Typically a governor is used to monitor the speed of the elevator car. According to standard safety regulations, such elevator systems must include an emergency braking device (known as a safety brake or "safety gear") which is capable of stopping the elevator car from moving downwards, even if the tension member breaks, by gripping a guide rail.

The risks associated with freefall of an elevator car in an elevator system are particularly acute for elevator systems employed in high-rise buildings, where more significant over speed may occur due to the increased drop. The actuation of the safety brake is usually mechanically controlled. An elevator system employing a mechanical governor and mechanically-actuated safety brake is shown in <FIG>, and described in greater detail below.

Electromechanical actuators have also been proposed, wherein a safety controller is in electrical communication with an electromagnetic component that can be controlled to effect movement of the safety brake via a mechanical linkage. It is an aim of the present disclosure to provide an improved safety brake system.

<CIT> discloses a selectively operable safety brake including a magnetic brake operably coupled to a rod and disposed adjacent to a metal component, the magnetic brake configured to move between an engaging position and a non-engaging position.

<CIT> discloses an actuation device for an elevator safety device configured for moving in a longitudinal direction along a guide member of an elevator system, comprising a base and a lever. The lever is pivotably supported by the base in a configuration allowing the lever to pivot between an engaged position and a disengaged position.

<CIT> discloses a braking device for braking and/or catching an elevator car, with a basic body, a braking means which, by abutting against a brake rail, is driven into a gap between the basic body and the brake rail and thus produces the braking forces, a spring member pressing the braking means in the direction of the brake rail and a retaining magnet which keeps the braking means, in its stand-by position, at a distance from the brake rail against the tension of the spring member and acts on a magnetic armature.

According to a first aspect of the invention there is provided a safety brake system for use in a conveyance system including a guide rail and a conveyance component moveable along the guide rail, the safety brake system comprising:.

Thus it will be appreciated by those skilled in the art that, if the electromagnet is switched from the first to the second state, for example if the conveyance component is detected to be moving too fast or accelerating at too great of a rate, the actuation component will move from the first position to the second position, thus moving relative to the electromagnet. The movement of the actuation component is transferred via the linkage mechanism so as to move the safety brake into the braking position. Thus, it will be understood that the linkage mechanism, which is coupled between the safety brake and the actuation component, is configured to move together with the actuation component thereby moving the safety brake into the braking position to engage with the guide rail and stop motion of the component.

The disclosed safety brake system may require fewer components than prior art mechanical safety brake devices which may therefore reduce the space required by the safety brake system. In addition, the reduction in the number of components may reduce the cost of installation and service. The disclosed safety brake system may further provide a system which is simple to maintain and provides robust performance.

It will further be understood that, in some examples of the disclosed safety brake system, there is no dependence on frictional forces to actuate the safety brake. Rather, the linkage mechanism may be caused to move to actuate the safety brake as a direct result of the movement of the actuation component, in other words, by the movement of the actuation component from the first position to the second position when the electromagnet is switched from the first state to the second state being transferred to the safety brake via the linkage mechanism.

It will be understood that the actuation component may for example be spaced apart from the electromagnet in the first position and then in contact with the electromagnet when in the second position or may be spaced apart from the electromagnet in both the first position and in the second position. In any example of the disclosure, the actuation component may be in contact with the electromagnet when in the first position and may be spaced apart from the electromagnet when in the second position.

In prior art mechanical safety brake devices, resetting the safety brake to the non-braking position after use can be complex and may, for example, involve realignment of the actuator and the safety brake before it is possible to reset the safety brake.

In one set of examples, the electromagnet may be switchable between the second state and a third state; the actuation component may be configured to move relative to the electromagnet from the second position when the electromagnet is in the second state to the first position when the electromagnet is in the third state; and the linkage mechanism may be coupled between the safety brake and the actuation component such that movement of the actuation component from the second position to the third position is transferred to the safety brake via the linkage mechanism, thus moving the safety brake to the non-braking position. In one set of examples, the third state may be the same as the first state. In an alternative set of examples the third state may be different to the first state.

In this set of examples, the safety brake may be reset automatically when the electromagnet is switched from the second state to the third state. In some examples, the safety brake might be reset only be switching the electromagnet from the second state to the third state. In any example of the disclosure however, to reset the safety brake from the braking position to the non-braking position, the conveyance component may optionally be moved along the guide rail in a direction opposite to the direction of movement of the conveyance component during a freefall, over-speed, or over-acceleration condition prior to or simultaneously with the electromagnet being switched from the second state to the third state so as to reset the safety brake. This may reduce the magnitude of the force required to be produced by the actuator to reset the safety brake.

In a set of examples, the electromagnet is fixed relative to the conveyance component. In one set of examples, the electromagnet could be fixed directly to the conveyance component. In an alternative set of examples however, the actuator may further comprise a mount portion for mounting the actuator to the conveyance component, and the electromagnet may be fixed relative to the mount portion.

The safety brake may be mounted to the conveyance component independently of the actuator, with the linkage mechanism extending between the safety brake and the actuator. However, in a set of examples, the mount portion also mounts the safety brake to the component such that the safety brake system is a single integrated unit or device. This arrangement is advantageous as the safety brake system may be provided as one unit which may be affixed to a conveyance component in a single installation step.

The mount portion could take any desired form. Thus, for example, the mount portion could comprise a flat plate. The mount portion could also be configured for mounting the safety brake to the conveyance component. In an alternative example, the mount portion could be provided by a housing of the actuator.

In a set of examples, the actuator may comprise a housing, wherein the housing encloses the electromagnet and the actuation component. The housing may protect the actuator from damage, for example due to becoming blocked with debris. The housing may further be configured so as to guide movement of the actuation component between the first position and the second position.

In one set of examples, the housing may be configured to be mounted directly to the conveyance component. In an alternative set of examples, the housing may be mounted to a further component of the safety brake system such as, for example, a mount portion configured to be mounted to the conveyance component.

It will be appreciated that the linkage mechanism could be configured such that movement of the actuation component in any direction could move the safety brake into the braking position. In one set of examples however, the safety brake may comprise a braking component configured to move into engagement with the guide rail when the safety brake moves to the braking position,
and the braking component may be coupled to the linkage mechanism such that the movement of the actuation component from the first position to the second position when the electromagnet is switched from the first state to the second state pushes or pulls the braking component in the direction of movement of the actuation component, thus moving the safety brake into the braking position. In this set of examples, the force required to be exerted on the actuation component to move the safety brake into the braking position may be relatively low, thus improving the efficiency of the safety brake system.

In one set of examples, the movement of the actuation component from the first position to the second position when the electromagnet is switched between the first and second states may push or pull the braking component along a braking axis, and the braking axis may be in-line with the lever axis. In an alternative set of examples, the linkage mechanism may be configured such that the braking axis is off-set from the lever axis. In any example of the disclosure, the braking axis may extend parallel to the lever axis or approximately parallel to the lever axis (where approximately means within + or - <NUM>°).

In one set of examples, the safety lever may be formed as a continuation of the linkage mechanism. In other words, the safety lever and the linkage mechanism may comprise a single component. In another set of examples, the safety lever may be a separate component from the linkage mechanism. In these examples, the safety lever and the linkage mechanism may be connected to one another via a pivoting joint.

In one set of examples, the solenoid may be energised with a first polarity when in the first state and with a second, opposite polarity when in the second state. In these examples, the solenoid may be energised with the first polarity when in the third state such that the third state is the same as the first state.

In another set of examples, the solenoid may be powered off when in the first state and energised with a first polarity when in the second state. It will be understood that in this set of examples, the solenoid may be energised with a second, opposite polarity when in the third state or it may be powered off such the third state is the same as the first state. In the examples in which the solenoid is powered off in the first state, the energy requirements during normal operation of the safety brake system are reduced as the solenoid may be operated with pulses of power to engage the safety brake instead of a continuous power supply.

In one set of examples, the first magnet is attracted towards the solenoid when the solenoid is in the first state and repulsed away from the solenoid when the solenoid is in the second state; and
the second magnet may be attracted towards the solenoid when the solenoid is in the second state.

In a set of examples, the second magnet may further be repulsed away from the solenoid when the solenoid is in the first state.

It will be understood that, in this set of examples, when the solenoid is powered off in the first state, the magnetic forces between the solenoid and the first and/or second permanent magnets may occur due to magnetic forces between the first and/or second permanent magnets and a steel core of the solenoid without additional forces exerted by an electromagnetic field generated by the solenoid when energised.

In any example of the disclosure, the actuation component may be configured to move relative to the electromagnet due to the force exerted by the electromagnet alone. In one set of examples however, the actuator may further comprise a biasing member configured to bias the actuation component away from or towards the electromagnet. The biasing member may be a spring or any other resilient member which can be configured to provide the biasing force to move the actuation component along the longitudinal axis in a direction away from or towards the electromagnet.

In a set of examples, the safety brake comprises a wedge brake. Some suitable wedge brake arrangements include a roller mounted to move relative to a wedge, or one or more wedge-shaped brake pads mounted to move into engagement with a guide rail. However, the safety brake may comprise any suitable arrangement for stopping motion of a component via mechanical engagement with a guide rail.

In examples of the present disclosure, the safety brake device may find use in a variety of conveyance systems, such as elevator systems, people conveyors, goods transporters, etc. The conveyance component that is moveable along a guide rail may be a platform, a counterweight or a cab for transporting goods or people. In some examples, the conveyance system is an elevator system and the conveyance component is an elevator car.

According to some further examples of the present disclosure, there is provided an elevator system comprising: an elevator car driven to move along at least one guide rail; and the safety brake system of any of the examples described above, wherein the electromagnet is fixed relative to the elevator car and the safety brake is arranged to be moveable between the non-braking position where the safety brake is not in engagement with the guide rail and the braking position where the safety brake is engaged with the guide rail. In such examples, the safety brake may be mounted to the elevator car independently of the actuator, or together with the actuator, for example, via the mounting portion.

In a set of examples, the elevator system comprises a speed sensor and a safety controller arranged to receive a speed signal from the speed sensor and to selectively switch the electromagnet from the first state to the second state upon detecting an overspeed or over-acceleration condition for the elevator car based on the speed signal. It will be appreciated that acceleration may be determined through processing of the speed signal to produce an acceleration signal e.g. by differentiating the speed signal.

In a set of examples, in addition or alternatively, the elevator system comprises an accelerometer and a safety controller arranged to receive an acceleration signal from the accelerometer and to selectively switch the electromagnet from the first state to the second state upon detecting an over-acceleration condition for the elevator car.

Therefore, when the elevator car is travelling at overspeed or over-acceleration, selectively switching the electromagnet from the first state to the second state will actuate the safety brake to engage with the guide rail, preventing further motion of the elevator car.

According to a second aspect of the invention, there is provided a method of operating a safety brake in a safety brake system, the safety brake system comprising:.

In a set of examples, the method may further comprise:.

In a set of examples, the method may further comprise initiating a reset of the safety brake system by switching the electromagnet from the second state to a third state so as to move the actuation component from the second position when the electromagnet is in the second state to the first position when the electromagnet is in the third state, wherein the linkage mechanism is coupled between the safety brake and the actuation component such that the movement of the actuation component from the second position to the first position is transferred to the safety brake via the linkage mechanism, thus moving the safety brake into the non-braking position.

In this set of examples, the safety brake may be reset automatically when the electromagnet is switched from the second state to the third state. Initiating a reset of the safety brake may further comprise moving the conveyance component along the guide rail in a direction opposite to the direction of movement of the conveyance component during a freefall, over-speed, or over-acceleration condition prior to or simultaneously to the electromagnet being switched from the second state to the third state so as to reset the safety brake. This may reduce the magnitude of the force required to be produced by the actuator to reset the safety brake.

In one set of examples, the third state may be the same as the first state. In an alternative set of examples the third state may be different to the first state. In either set of examples, the electromagnet may comprise a solenoid. The solenoid may be powered off in the first state and powered on in the second and third states. The solenoid may be powered on with the same or opposite polarities in the second and third states.

In a set of examples, the method may further include moving a braking component of the safety brake into engagement with the guide rail when the safety brake moves to the braking position, wherein the braking component is coupled to the linkage mechanism such that the movement of the actuation component from the first position to the second position when the electromagnet is switched between the first and second states pushes or pulls the braking component in the direction of movement of the actuation component, thus moving the safety brake into the braking position.

In a set of examples, operating the electromagnet in the emergency stop mode to move the actuation component from the first position to the second position may comprise moving the actuation component between the first position and the second position along the lever axis.

In a set of examples, operating the electromagnet in the emergency stop mode to move the actuation component from the first position to the second position may push or pull the braking component along a braking axis,.

In a set of examples, operating the electromagnet in an emergency stop mode may further include moving the second actuation component of the actuator,.

According to some further examples of the present disclosure, there is provided a method of operating an elevator system, the method comprising driving an elevator car to move along at least one guide rail and operating the safety brake in the safety brake system, wherein the electromagnet is fixed relative to the elevator car and the safety brake is arranged to be moveable between the non-braking position where the safety brake is not in engagement with the guide rail and the braking position where the safety brake is engaged with the guide rail.

As mentioned above, such methods may find use in a variety of conveyance systems, but in at least some examples the methods are used to operate a safety brake in a safety brake device in an elevator system and the conveyance component is an elevator car.

<FIG> shows a conveyance system, in this example an elevator system, generally indicated at <NUM>. The elevator system <NUM> includes cables or belts <NUM>, a car frame <NUM>, a conveyance component, in this example an elevator car <NUM>, roller guides <NUM>, guide rails <NUM>, a governor <NUM>, and a pair of safety brakes <NUM> mounted on the elevator car <NUM>. The governor <NUM> is mechanically coupled to actuate the safety brakes <NUM> by linkages <NUM>, levers <NUM>, and lift rods <NUM>. Governor <NUM> includes a governor sheave <NUM>, rope loop <NUM>, and a tensioning sheave <NUM>. Cables <NUM> are connected to car frame <NUM> and a counterweight (not shown in <FIG>) inside a hoistway. Elevator car <NUM>, which is attached to car frame <NUM>, moves up and down the hoistway by force transmitted through cables or belts <NUM> to car frame <NUM> by an elevator drive (not shown) commonly located in a machine room at the top of the hoistway. Roller guides <NUM> are attached to car frame <NUM> to guide the elevator car <NUM> up and down the hoistway along the guide rails <NUM>. Governor sheave <NUM> is mounted at an upper end of the hoistway. Rope loop <NUM> is wrapped partially around governor sheave <NUM> and partially around tensioning sheave <NUM> (located in this example at a bottom end of the hoistway). Rope loop <NUM> is also connected to elevator car <NUM> at lever <NUM>, ensuring that the angular velocity of governor sheave <NUM> is directly related to the speed of elevator car <NUM>.

In the elevator system <NUM> shown in <FIG>, the governor <NUM>, a machine brake (not shown) located in the machine room, and the safety brakes <NUM> act to stop the elevator car <NUM> if it exceeds a set speed as it travels inside the hoistway. If elevator car <NUM> reaches an over-speed or over-acceleration condition, the governor <NUM> is triggered initially to engage a switch, which in turn cuts power to the elevator drive and drops the machine brake to arrest movement of the drive sheave (not shown) and thereby arrest movement of elevator car <NUM>. If, however, the elevator car <NUM> continues to experience an over speed condition, governor <NUM> may then act to trigger the safety brakes <NUM> to arrest movement of elevator car <NUM>. In addition to engaging a switch to drop the machine brake, governor <NUM> also releases a clutching device that grips the governor rope <NUM>. Governor rope <NUM> is connected to the safety brakes <NUM> through mechanical linkages <NUM>, levers <NUM>, and lift rods <NUM>. As elevator car <NUM> continues its descent, governor rope <NUM>, which is now prevented from moving by actuated governor <NUM>, pulls on the operating levers <NUM>. The operating levers <NUM> actuate the safety brakes <NUM> by moving linkages <NUM> connected to lift rods <NUM>, which lift rods <NUM> cause the safety brakes <NUM> to engage the guide rails <NUM> to bring the elevator car <NUM> to a stop.

Mechanical speed governor systems are being replaced in some elevators by electronically-actuated systems. A safety brake system <NUM> is described herein that is suitable for electronic or electrical control of actuating and resetting a safety brake in an elevator system. It will be understood that the safety brake system of the present disclosure could be used in an elevator system <NUM> of the type shown in <FIG>. However, this is only one example of a system in which the safety brake of the disclosure could be used. The safety brake system of the present disclosure could also be used in any other suitable type of elevator system. Such other types of elevator system may include (but are not limited to) hydraulic elevator systems and ropeless elevator systems such as pinched wheel or linear motor propulsion elevator systems.

<FIG> show an example of a safety brake system <NUM> with the safety brake <NUM> in a first, non-braking position and a second, braking position respectively. The safety brake system <NUM> can be mounted onto the elevator car <NUM> of <FIG> to actuate the safety brake without relying on a mechanical coupling to the governor <NUM>. The safety brake system <NUM> includes a mount <NUM> which may be mounted on the external surface of the elevator car <NUM>. The mount <NUM> includes apertures <NUM> which enable fixation of the mount <NUM> to the elevator car frame <NUM> (as seen in <FIG>).

The safety brake system <NUM> comprises a safety brake <NUM> which is moveable between a non-braking position where the safety brake <NUM> is not in engagement with the guide rail <NUM>, and a braking position where the safety brake <NUM> is engaged with the guide rail <NUM>. The safety brake <NUM> is illustrated as a wedge-type safety brake comprising an angled "wedge" surface <NUM> which is fixed relative to the mount <NUM> and a roller <NUM> moveable along the surface from a non-braking position (as seen in <FIG>) to a braking position where the roller <NUM> is brought into engagement with the guide rail <NUM> (as seen in <FIG>). Such wedge-type safety brakes are well-known in the art, for example as seen in <CIT>. However, it will be appreciated that the safety brake <NUM> may take any suitable form and could instead comprise any suitable form of braking component including a wedge-shaped brake pad, or a magnetic brake pad instead of the roller. Further, the safety brake <NUM> could comprise first and second rollers or brake pads adapted to be brought into engagement with the guide rail on first and second opposite sides thereof.

Regardless of the exact form of the safety brake <NUM>, the safety brake <NUM> is coupled to an actuator <NUM> via a linkage mechanism <NUM>. The actuator <NUM> comprises an electromagnet switchable between a first state and a second state and an actuation component configured to move relative to the electromagnet along an axis between a first position when the electromagnet is in a first state and a second position when the electromagnet is in a second state. The actuation component is therefore configured to provide movement of the linkage mechanism <NUM>, thus moving the safety brake <NUM> between the non-braking and braking positions.

In the example of <FIG>, as described below, the electromagnet is a solenoid <NUM> and the actuation component comprises a first permanent magnet <NUM>. The actuator further comprises a second permanent magnet <NUM> and a spring <NUM>.

The linkage mechanism <NUM> is coupled at one end to the roller <NUM> and extends along an axis <NUM> parallel to or within <NUM>° of parallel to the guide rail <NUM>. As seen, the safety brake <NUM> is located below the actuator <NUM> in this example such that the linkage mechanism <NUM> can act to pull the roller <NUM> upwardly along the "wedge" surface <NUM> to move the safety brake <NUM> into the braking position. The roller <NUM> in the example shown is pulled upwardly along a braking axis, which in the example shown corresponds to the axis <NUM>.

The actuator <NUM> further includes a housing <NUM> which is fixed to the mount <NUM> and encloses the solenoid <NUM>, the first permanent magnet <NUM>, the second permanent magnet <NUM> and the spring <NUM>. The housing <NUM> may take any suitable shape and, in the example shown, comprises a cylindrical hollow body, having a longitudinal axis A-A and first and second closed ends <NUM>, <NUM>. A safety lever <NUM> is provided, which in the example of <FIG>, is formed as a continuation of the linkage mechanism <NUM>. In any example of the disclosure and as shown in <FIG> (in which components which correspond to those of <FIG> are shown with like reference numbers), the safety lever 72c may alternatively be a separate component from the linkage mechanism 54c. As seen, one end E of the safety lever 72c is coupled to the end L of the linkage mechanism 54c which is not coupled to the roller <NUM> via a pivoting joint <NUM>.

In the example of <FIG>, the safety lever <NUM> extends into the housing <NUM> through the first closed end <NUM> thereof along a lever axis, which in the example shown corresponds to the longitudinal axis A-A of the housing and through the second closed end <NUM> thereof.

The solenoid <NUM> may take any suitable shape and, in the example shown, is disc shaped. The solenoid is fixed in position relative to the housing <NUM> and thus is also fixed relative to the elevator car <NUM>. In the example shown, the solenoid <NUM> extends across the full internal diameter of the housing <NUM>, the perimeter of the disc shaped solenoid engaging with the inner wall of the housing <NUM>. The safety lever <NUM> extends through an aperture (not shown) in the solenoid and can move axially relative thereto. The solenoid <NUM> is spaced from both the first and second closed ends <NUM>, <NUM> of the housing such that a first chamber <NUM> is formed between the first closed end and the solenoid <NUM> and a second chamber <NUM> is formed between the second closed end and the solenoid <NUM>.

The safety lever <NUM> extends through the first and second permanent magnets <NUM>, <NUM>. The safety lever <NUM> is fixed to the first permanent magnet <NUM> and to the second permanent magnet <NUM> such that the safety lever <NUM>, the first permanent magnet <NUM> and the second permanent magnet <NUM> are configured to move simultaneously and together along the axis <NUM> relative to the solenoid <NUM>. The solenoid <NUM> is positioned axially between the first permanent magnet <NUM> and the second permanent magnet <NUM> such that the first permanent magnet <NUM> is positioned in the first chamber <NUM> and the second permanent magnet <NUM> is positioned in the second chamber <NUM>.

The first permanent magnet <NUM> comprises a flange, in the example shown, an annular flange <NUM>, the perimeter of which engages with the inner wall of the housing <NUM>. A body, a cylindrical body <NUM> in the example shown, extends axially away from a radially inner edge of the annular flange <NUM> and is closed at an opposite end <NUM> thereof. The spring <NUM>, which is a helical compression spring in the example shown, is housed in the body <NUM> of the first permanent magnet <NUM> and extends between the solenoid <NUM> and the closed end <NUM> of the first permanent magnet <NUM>. The spring is biased to push the first permanent magnet <NUM> away from the solenoid <NUM> along the axis <NUM>. The safety lever <NUM> extends though the centre of the spring <NUM> such that buckling of the spring may be restricted by the safety lever <NUM>.

<FIG> shows the safety brake system <NUM> in a non-braking position, e.g. upon installation or after reset. In this position, the first permanent magnet <NUM> is held in contact with the solenoid <NUM> by the magnetic force between the first permanent magnet <NUM> and the solenoid <NUM>. In this regard, the magnetic force between the first permanent magnet <NUM> and the solenoid <NUM> is configured to oppose and overcome the biasing force provided by the spring <NUM>. The second permanent magnet <NUM> is held in a position spaced apart from the solenoid <NUM> by the magnetic force between the second permanent magnet <NUM> and the solenoid <NUM>. It will be appreciated that in this and other examples, the first and the second permanent magnets are configured such that when one of the first and second permanent magnets is attracted towards the solenoid <NUM>, the other one of the first and the second permanent magnets is repulsed away from the solenoid <NUM>. In this example, the solenoid <NUM> is energised with a positive polarity when the safety brake system <NUM> is in a non-braking position. In other examples, the solenoid <NUM> may be energised with a negative polarity when the safety brake system <NUM> is in a non-braking position.

A controller <NUM> (shown in <FIG>) is in electrical communication with the solenoid <NUM>. In the example shown, in normal operating conditions, the solenoid <NUM> is energised with a positive polarity. If a freefall, over-speed, or over-acceleration condition of the elevator car <NUM> is detected by the governor <NUM>, the controller <NUM> is configured to switch the solenoid <NUM> to be energised with a negative polarity, such that the first permanent magnet <NUM> is moved away from the solenoid <NUM> along the axis <NUM> from a first axial position to a second axial position by the repulsive magnetic force between the first permanent magnet <NUM> and the solenoid <NUM>.

In the example of <FIG>, the first permanent magnet <NUM> is stopped by and/or rests against the first closed end <NUM> of the housing when in the second axial position. The biasing force provided by the spring <NUM> acts in the same direction as the repulsive magnetic force between the first permanent magnet <NUM> and the solenoid <NUM> and so also acts to move the first permanent magnet <NUM> away from the solenoid <NUM>. At the same time, the second permanent magnet <NUM> is moved towards the solenoid <NUM> along the axis <NUM> by an attractive magnetic force between the second permanent magnet <NUM> and the solenoid <NUM>. In other words, the safety lever <NUM> is moved along the axis <NUM> in the direction of travel of the first and second permanent magnets by the net balance of the biasing force provided by the spring <NUM>, the repulsion force between the first permanent magnet <NUM> and the solenoid <NUM> and the attraction force between the second permanent magnet <NUM> and the solenoid <NUM>.

The safety lever <NUM> is continuous with or coupled to the linkage mechanism <NUM> as described above in relation to <FIG>. The linkage mechanism <NUM> is linked to the roller <NUM> or a similar component of the safety brake <NUM> such that the movement of the safety lever <NUM> pulls the roller <NUM> or other safety brake component upwardly in the example shown (but more generally in a direction opposite to the direction of movement of the elevator car during a freefall, over-speed, or over-acceleration condition) thus moving the safety brake <NUM> into the braking position such that it engages the guide rail and prevents further downwards motion of the elevator car <NUM>. In other words, the safety brake <NUM> is actuated as a result of the solenoid <NUM> being switched by the controller <NUM> from a first state where the solenoid <NUM> is energised with a positive polarity to a second state where the solenoid <NUM> is energised with a negative polarity.

To reset the safety brake <NUM> and the actuator <NUM> of the safety brake system <NUM> from the braking to the non-braking position, the solenoid <NUM> is switched to be energised with a positive polarity by the controller <NUM>, creating an attractive magnetic force between the first permanent magnet <NUM> and the solenoid <NUM> and a repulsive magnetic force between the second permanent magnet <NUM> and the solenoid <NUM>. The biasing force provided by the spring <NUM> opposes movement of the first permanent magnet <NUM> towards the solenoid <NUM>. The attractive magnetic force between the first permanent magnet <NUM> and the repulsive magnetic force between the second permanent magnet <NUM> and the solenoid <NUM> overcome the biasing force provided by the spring <NUM> and the first permanent magnet <NUM> is moved into contact with the solenoid <NUM>. In this and other examples, the elevator car <NUM> may optionally be moved along the guide rail in a direction opposite to the direction of movement of the elevator car during a freefall, over-speed, or over-acceleration condition prior to the solenoid <NUM> being switched by the controller <NUM> to reset the safety brake.

Moving the elevator car as described reduces the magnitudes of forces required to be generated by the actuator <NUM>. It will be understood however that in some examples, the elevator car may not be moved as described prior to the solenoid <NUM> being switched by the controller <NUM> to reset the safety brake.

A further non-claimed example of the safety brake system is shown in <FIG> are shown in the frame of reference of the elevator car <NUM>. The safety brake system <NUM> displayed in <FIG> uses the same mechanism as the safety brake system <NUM> in <FIG> to engage the safety brake <NUM>. However, in the example of <FIG> the actuator comprises only a first permanent magnet <NUM> and a spring <NUM>. Thus, no second permanent magnet is included in this version of the actuator <NUM>.

<FIG> shows the safety brake system <NUM> in a non-braking position, e.g. upon installation or after reset. In this position, the first permanent magnet <NUM> is held in contact with the solenoid <NUM> by the magnetic force between the first permanent magnet <NUM> and the solenoid <NUM>. In this regard, the magnetic force between the first permanent magnet <NUM> and the solenoid <NUM> is configured to oppose and overcome the biasing force provided by the spring <NUM>. In this example, the solenoid <NUM> is energised with a positive polarity. In other examples, the solenoid <NUM> may be energised with a negative polarity when the safety brake system <NUM> is in a non-braking position.

A controller <NUM> (shown in <FIG>) is in electrical communication with the solenoid <NUM>. In the example shown, in normal operating conditions, the solenoid <NUM> is energised with a positive polarity. If a freefall, over-speed, or over-acceleration condition of the elevator car <NUM> is detected by the governor <NUM>, the controller <NUM> is configured to switch the solenoid <NUM> to be energised with a negative polarity, such that the first permanent magnet <NUM> is moved away from the solenoid <NUM> along the axis <NUM> from a first axial position to a second axial position by the repulsive magnetic force between the first permanent magnet <NUM> and the solenoid <NUM>. In the example of <FIG>, the first permanent magnet <NUM> is stopped by and/or rests against the first closed end <NUM> of the housing <NUM> when in the second axial position. The biasing force provided by the spring <NUM> acts in the same direction as the repulsive magnetic force between the first permanent magnet <NUM> and the solenoid <NUM> and so also acts to move the first permanent magnet <NUM> away from the solenoid <NUM>. In other words, the safety lever <NUM> is moved along the axis <NUM> in the direction of travel of the first permanent magnet <NUM> by the net balance of the biasing force provided by the spring <NUM> and the repulsion force between the first permanent magnet <NUM> and the solenoid <NUM>.

To reset the safety brake <NUM> and the actuator <NUM> of the safety brake system <NUM> from the braking to the non-braking position, the solenoid <NUM> is switched to be energised with a positive polarity by the controller <NUM>, creating an attractive magnetic force between the first permanent magnet <NUM> and the solenoid <NUM>. The biasing force provided by the spring <NUM> opposes movement of the first permanent magnet1 <NUM> towards the solenoid <NUM>. The attractive magnetic force between the first permanent magnet <NUM> overcomes the biasing force provided by the spring <NUM> and the first permanent magnet <NUM> is moved into contact with the solenoid <NUM>. Thus, movement of the first permanent magnet <NUM> back to its non-braking position will move the safety lever <NUM> such that the safety lever <NUM> pushes the roller <NUM> or other safety brake component downwardly thus moving the safety brake <NUM> back into the non-braking position such that it disengages from the guide rail <NUM>. In this and other examples, the elevator car <NUM> may optionally be moved along the guide rail in the direction opposite to the direction of movement of the elevator car during a freefall, over-speed, or over-acceleration condition prior to the solenoid <NUM> being switched to be energised with a positive polarity by the controller <NUM>. It will be understood however that in this and other examples, the elevator car may not be required to be moved prior to the solenoid <NUM> being switched by the controller <NUM> to reset the safety brake.

A third example of the safety brake system is shown in <FIG> are shown in the frame of reference of the elevator car <NUM>. The safety brake system <NUM> displayed in <FIG> uses the same mechanism as the safety brake system <NUM> in <FIG> to engage the safety brake <NUM>. However, the example of <FIG>, does not comprise a spring in another version of the actuator <NUM>. Thus movement of the first permanent magnet <NUM> relative to the solenoid <NUM> is caused by a repulsive force generated between the first permanent magnet <NUM> and the solenoid <NUM> when the solenoid is switched from a first state to a second state. It will be understood that the first permanent magnet <NUM> could take any suitable form. In the example shown, the first permanent magnet <NUM> is disc shaped and is configured such that an upper surface of the first permanent magnet <NUM> rests against the first closed end <NUM> of the housing <NUM> when in the second axial position.

It will further be understood that the safety brake system <NUM> of this example comprises both a first and a second permanent magnet <NUM>, <NUM>.

A fourth non-claimed example of the safety brake system is shown in <FIG> are shown in the frame of reference of the elevator car <NUM>. The safety brake system <NUM> displayed in <FIG> uses the same mechanism as the safety brake system <NUM> in <FIG> to engage the safety brake <NUM>. However, in the example of <FIG> the actuator <NUM> comprises an electromagnet <NUM> rather than a solenoid and the actuation component <NUM> comprises a ferromagnetic component which may have the same shape as the first permanent magnet <NUM> of the example of <FIG>. The actuator <NUM> further comprises a spring <NUM> and a safety lever <NUM> as in the example of <FIG>.

The electromagnet <NUM> is fixed in position relative to the housing <NUM> and relative to the elevator car <NUM>. The safety lever <NUM> and the actuation component <NUM> move relative to the electromagnet <NUM>. The safety lever <NUM> extends through the electromagnet <NUM>, through the actuation component <NUM> and through the housing <NUM>. The safety lever <NUM> has an axis <NUM> and is fixed to the actuation component <NUM> such that the safety lever <NUM> and the actuation component <NUM> move simultaneously and together along the axis <NUM>.

<FIG> shows the safety brake system <NUM> in a non-braking position, e.g. upon installation or after reset. The electromagnet is powered on such that the actuation component <NUM> is held in contact with the electromagnet <NUM> by the magnetic force provided by the electromagnet <NUM> which overcomes the biasing force provided by the spring <NUM>. A controller <NUM> (seen in <FIG>) is in electrical communication with the electromagnet <NUM> and is configured to control a supply of electricity to the electromagnet <NUM>.

If a freefall, over-speed, or over-acceleration condition of the elevator car <NUM> is detected by the governor <NUM>, the controller (seen in <FIG>) removes or reduces electrical power to the electromagnet <NUM> so as to switch the electromagnet from a first state to a second state. On removal or reduction of power to the electromagnet <NUM>, the actuation component <NUM> is released by the electromagnet. When the actuation component <NUM> is released, the biasing force applied by the spring <NUM> to the actuation component <NUM> acts to move the actuation component <NUM> away from the electromagnet <NUM> along the axis <NUM> from a first axial position to a second axial position. The safety lever <NUM> moves with the actuation component <NUM>. The safety lever <NUM> is linked to the safety brake <NUM> such that the movement of the safety lever <NUM> pulls the safety brake thus moving the safety brake <NUM> into the braking position. In other words, the safety brake <NUM> is actuated as a result of the electromagnet <NUM> being switched between a first state where the electromagnet <NUM> is powered on and a second state where the power supplied to the electromagnet <NUM> is removed or reduced.

To reset the safety brake <NUM> and the actuator <NUM> of the safety brake system <NUM>, the controller restores or increases power to the electromagnet <NUM> creating an attractive magnetic force between the electromagnet <NUM> and the actuation component <NUM>. The attractive magnetic force overcomes the biasing force provided by the spring <NUM> and as a result the actuation component <NUM> moves towards the electromagnet along the axis <NUM> from the second axial position to the first axial position. In this and other examples, the elevator car <NUM> may optionally be moved along the guide rail in the direction opposite of the direction of movement of the elevator car during a freefall, over-speed, or over-acceleration condition prior to power being restored to electromagnet <NUM> by the controller <NUM>.

A further example of the safety brake system is shown in <FIG> in the frame of reference of the elevator car <NUM>. The safety brake system <NUM> displayed in <FIG> uses the same actuator and the same safety brake as the safety brake system <NUM> in <FIG>. However, in the example of <FIG> the safety lever <NUM> of the actuator <NUM> is not continuous with the linkage mechanism <NUM>.

The housing <NUM> comprises a hollow body, having a longitudinal axis A1-A1 and first and second closed ends <NUM>, <NUM>. In the example shown, the hollow body is cylindrical but it will be understood that it could be any other suitable shape such as cuboid or rectangular cuboid for example. The safety lever <NUM> extends into the housing <NUM> through the first closed end <NUM> thereof along the longitudinal axis A1-A1 of the housing <NUM> and through the second closed end <NUM> thereof. A first end <NUM> of the safety lever <NUM> is located between the housing <NUM> and the safety brake <NUM>. A pivot linkage <NUM> connects the first end <NUM> of the safety lever <NUM> to the end of the safety brake linkage mechanism <NUM> which is not coupled to the roller <NUM>. The end of the linkage mechanism <NUM> which is not coupled to the roller <NUM> extends through a second longitudinal axis B1-B1 parallel to and offset from the first longitudinal axis A1-A1 of the safety lever <NUM>. The end of the safety lever <NUM> is coupled to the pivot linkage <NUM> via a first fastener <NUM> such as a pin extending through a first slot <NUM> extending longitudinally along the pivot linkage <NUM> approximately midway along the pivot linkage <NUM>. The end of the linkage mechanism <NUM> which is not coupled to the roller <NUM> is coupled to the pivot linkage <NUM> via a second fastener <NUM> such as a pin extending through a second slot <NUM> extending longitudinally along the pivot linkage <NUM> at an end thereof. An opposite end of pivot linkage <NUM> is attached to mount <NUM> via a pin <NUM> forming a pivoting point such that movement of the safety lever <NUM> along the first longitudinal axis A1-A1 causes safety lever <NUM> to move within the first slot <NUM> thus rotating pivot linkage <NUM> about pivoting point. The rotation of pivot linkage <NUM> in turn causes the linkage mechanism <NUM> to move within the second slot <NUM> and to move along the second longitudinal axis B1-B1. In other words, the pivot linkage <NUM> is configured so as to cause movement of the safety lever <NUM> along the first longitudinal axis A1-A1 to move the linkage mechanism <NUM> along the second longitudinal axis B1-B1 in the same direction.

In all the examples of <FIG>, the actuator <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is shown as being mounted above the safety brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> such that the safety lever <NUM>, 72c <NUM>, <NUM>, <NUM>, <NUM> acts to pull the safety brake upwardly to engage the safety brake. It will be understood however that, in any example of the disclosure, the safety brake could be mounted above the actuator such that the safety lever acts to push the safety brake upwardly to engage the safety brake. Such an arrangement is shown in the example of <FIG> in which components which correspond to those of <FIG> are shown with like reference numbers, which is again shown in the frame of reference of the elevator car <NUM>. In this example, the linkage mechanism <NUM> is coupled at one end to the roller <NUM> and extends along an axis <NUM> parallel to or within <NUM>° of parallel to the guide rail <NUM>. As seen, the safety brake <NUM> is located above the actuator <NUM> in this example such that the linkage mechanism <NUM> can act to push the roller <NUM> upwardly along the "wedge" surface <NUM> to move the safety brake <NUM> into the braking position. The roller <NUM> in the example shown is pushed upwardly along a braking axis, which in the example shown corresponds to the axis <NUM>. The safety brake system <NUM> displayed in <FIG> again uses the same actuator and the same safety brake as the safety brake system <NUM> in <FIG>.

Further, all the examples shown are configured for vertical movement of the elevator car <NUM> along a guide rail. It will be appreciated however that the examples of the disclosure could equally apply to an elevator or conveyance system in which the conveyance component is configured to move horizontally or in another non-vertical direction.

In an alternative set of examples of operating any safety brake system <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, including an actuator having a solenoid (for example as shown in <FIG>, <FIG>, <FIG>, <FIG> and <FIG>) the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is powered off in normal operating conditions. In other words, when the safety brake system <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is in a non-braking-position, e.g., upon installation or after reset, no power is supplied to the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> by the controller <NUM>. In this position, the first permanent magnet <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is held in contact with the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> by the magnetic force between the first permanent magnet <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. It will be understood that, in this set of examples, the magnetic force between the first permanent magnet <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is the magnetic force occurring between the first permanent magnet <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and a steel core of the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and is not the result of an electromagnetic field generated by the solenoid when energised. If a freefall, over-speed, or over-acceleration condition of the elevator car <NUM> is detected by the governor <NUM>, the controller <NUM> is configured to energise the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> with a first polarity, such that the first permanent magnet <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is moved away from the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> along the axis <NUM>, <NUM> from a first axial position to a second axial position by the repulsive magnetic force between the first permanent magnet <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. In other words, the safety brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is actuated as a result of the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> being switched by the controller <NUM> from a first state where the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is powered off to a second state where the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is energised with a first polarity. In this set of examples, the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be energised with a second, opposite polarity by the controller <NUM> to reset the safety brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the actuator <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the safety brake system <NUM>, <NUM>, <NUM>, <NUM>, <NUM> from the braking to the non-braking position. In other words, the safety brake system may be reset as a result of the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> being switched by the controller <NUM> from the second state where the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is energised with a first polarity to a third state where the solenoid is energised with a second, opposite polarity to that of the second state. In these examples, after the safety brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and the actuator <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the safety brake system <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are reset, the solenoid may be powered off and thus switched back to the first state by the controller <NUM> so as to conserve energy. In other alternative examples in which the solenoid is powered off in the first state, the safety brake system may be reset as a result of the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> being switched by the controller <NUM> from the second state where the solenoid <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is energised with a first polarity to a third state which is the same as the first state in which the solenoid is powered off.

<FIG> shows a schematic block diagram of emergency braking control for the elevator system <NUM> and safety brake system <NUM>. The safety brake system is mounted onto the elevator car <NUM>. The elevator system <NUM> further comprises a speed sensor <NUM>, accelerometer <NUM> and a controller <NUM>. The speed sensor <NUM> measures the speed of descent and ascent of the elevator car <NUM>. The accelerometer <NUM> measures the acceleration of the elevator car <NUM>. The controller <NUM> is arranged to receive a speed signal <NUM> from the speed sensor <NUM>, and an acceleration signal <NUM> from the accelerometer <NUM>, and to control an electrical power supply <NUM> to the electromagnet <NUM> in the safety brake system. It will be understood that in this case the electromagnet may also be a solenoid. The controller <NUM> will selectively reduce, activate or disconnect the electrical power supply <NUM> to the electromagnet <NUM> to switch the electromagnet from a first state to a second state, e.g. upon the controller <NUM> detecting an overspeed condition for the elevator car <NUM> based on the speed signal <NUM>, and/or upon the controller <NUM> detecting an over-acceleration condition for the elevator car <NUM> based on the speed signal <NUM> and/or the acceleration signal <NUM>.

Claim 1:
A safety brake system (<NUM>; <NUM>; <NUM>; <NUM>) for use in a conveyance system including a guide rail (<NUM>) and a conveyance component moveable along the guide rail, the safety brake system comprising:
a safety brake (<NUM>; <NUM>; <NUM>; <NUM>) moveable between a non-braking position where the safety brake is not in engagement with the guide rail and a braking position where the safety brake is engaged with the guide rail;
a linkage mechanism (<NUM>; 54c; <NUM>; <NUM>; <NUM>); and
an actuator (<NUM>; <NUM>; <NUM>; <NUM>) for the safety brake, the actuator being configured to be mounted to the conveyance component and comprising:
an electromagnet (<NUM>; <NUM>; <NUM>; <NUM>) switchable between a first state and a second state;
an actuation component (<NUM>; <NUM>; <NUM>; <NUM>) configured to move relative to the electromagnet from a first position when the electromagnet is in the first state to a second position when the electromagnet is in the second state;
a safety lever (<NUM>; 72c; <NUM>; <NUM>; <NUM>), the safety lever being fixed to the actuation component (<NUM>; <NUM>; <NUM>; <NUM>) for movement therewith and extending from the electromagnet (<NUM>; <NUM>; <NUM>; <NUM>) to the actuation component along a lever axis, wherein the actuation component is configured to move between the first position and the second position along the lever axis; and
a second actuation component fixed to the safety lever (<NUM>; 72c; <NUM>; <NUM>; <NUM>) so as to move with the actuation component (<NUM>; <NUM>; <NUM>; <NUM>), wherein the electromagnet (<NUM>; <NUM>; <NUM>; <NUM>) is positioned axially between the actuation component and the second actuation component,
wherein the linkage mechanism is coupled between the safety brake and the actuation component such that movement of the actuation component from the first position to the second position when the electromagnet is switched from the first state to the second state is transferred to the safety brake via the linkage mechanism, thus moving the safety brake into the braking position,
wherein the electromagnet is a solenoid (<NUM>; <NUM>; <NUM>; <NUM>), the actuation component is a first permanent magnet (<NUM>; <NUM>; <NUM>; <NUM>) and the second actuation component comprises a second permanent magnet (<NUM>; <NUM>; <NUM>; <NUM>) and wherein the first and the second permanent magnets have opposite polarities.