The subject matter disclosed herein relates generally to the field of propulsion systems, and more particularly, to a lateral transfer station for an elevator having a magnetic screw propulsion system.
Self-propelled elevator systems, also referred to as ropeless elevator systems, are useful in certain applications (e.g., high rise buildings) where the mass of the ropes for a roped system is prohibitive and there is a need for multiple elevator cars in a single hoistway. An exemplary self-propelled elevator system is disclosed in published International application WO2014081407. There exist self-propelled elevator systems in which a first hoistway is designated for upward traveling elevator cars and a second hoistway is designated for downward traveling elevator cars. A transfer station at each end of the hoistway is used to move cars laterally between the first hoistway and second hoistway.
According to an exemplary embodiment, an elevator system includes an elevator car for travel in a hoistway; a stator positioned along the hoistway; and a magnetic screw assembly coupled to the car, the magnetic screw assembly coacting with the stator to impart motion to the elevator car; the stator including a service section having a plurality of poles to coact with the magnetic screw assembly; the stator including a transfer station section, the transfer station section of the stator including a plurality of stator permanent magnets.
In addition to one or more of the features described above, or as an alternative, further embodiments could include the magnetic screw including a first permanent magnet arranged along a helical path, a pitch of the helical path matching a pitch of first stator permanent magnets.
In addition to one or more of the features described above, or as an alternative, further embodiments could include the magnetic screw including a second permanent magnet arranged along a second helical path, a pitch of the second helical path matching a pitch of second stator permanent magnets, the second permanent magnet having an opposite polarity to the first permanent magnet.
In addition to one or more of the features described above, or as an alternative, further embodiments could include the service section of the stator has a first arc and the transfer station section of the stator surrounds has a second arc, the first arc greater than the second arc.
In addition to one or more of the features described above, or as an alternative, further embodiments could include the first arc is greater than about 180° and the second arc is less than or equal to about 180°.
In addition to one or more of the features described above, or as an alternative, further embodiments could include the first arc is greater than about 270°.
In addition to one or more of the features described above, or as an alternative, further embodiments could include a backup propulsion assembly coupled to the car, the backup propulsion assembly including a mechanical screw, wherein in the transfer station section of the stator, the poles proximate the mechanical screw are removed.
In addition to one or more of the features described above, or as an alternative, further embodiments could include the mechanical screw of the backup propulsion assembly traveling within the service section of the stator when the backup propulsion assembly is inactive.
In addition to one or more of the features described above, or as an alternative, further embodiments could include the mechanical screw of the backup propulsion assembly engaging the service section of the stator when the backup propulsion assembly is active.
In addition to one or more of the features described above, or as an alternative, further embodiments could include a brake positioned at an end of the magnetic screw assembly to apply a braking force to the magnetic screw assembly.
In addition to one or more of the features described above, or as an alternative, further embodiments could include at least one support in the hoistway, the support extendable beneath the car upon the car traveling in the transfer station section of the stator.
According to another exemplary embodiment, a method for positioning an elevator car in a lateral transfer station, the car having a magnetic screw assembly coupled thereto coacting with a stator in the hoistway includes operating the magnetic screw assembly to position the car in a transfer station; and operating the magnetic screw assembly to align permanent magnets of the magnetic screw assembly with stator permanent magnets of the same polarity in a transfer station section of the stator.
In addition to one or more of the features described above, or as an alternative, further embodiments could include prior to operating the magnetic screw assembly to align permanent magnets of the magnetic screw assembly with stator permanent magnets: engaging a support to be positioned under the car; operating the magnetic screw assembly to place the car in contact with the support.
In addition to one or more of the features described above, or as an alternative, further embodiments could include imparting lateral motion to the elevator car to move the elevator car away from the stator.
In addition to one or more of the features described above, or as an alternative, further embodiments could include operating the magnetic screw assembly to align permanent magnets of the magnetic screw assembly with stator permanent magnets includes rotating the magnetic screw one half rotation.
Other aspects, features, and techniques of embodiments of the invention will become more apparent from the following description taken in conjunction with the drawings.
Referring now to the drawings wherein like elements are numbered alike in the FIGURES:
A controller 20 provides control signals to the magnetic screw assemblies 18 and 18′ to control motion of the car (e.g., upwards or downwards) and to stop car 12. Controller 20 may be implemented using a general-purpose microprocessor executing a computer program stored on a storage medium to perform the operations described herein. Alternatively, controller 20 may be implemented in hardware (e.g., ASIC, FPGA) or in a combination of hardware/software. Controller 20 may also be part of an elevator control system. Power source 22 provides power to motors in the magnetic screw assemblies 18 and 18′ under the control of controller 20. Power source 22 may be distributed along a rail in the hoistway 14 to power magnetic screw assemblies 18 and 18′ as car 12 travels. A speed sensor 24 provides a speed signal indicative of the speed of car 12 to controller 20. Controller 20 can alter the control signals to the magnetic screw assemblies 18 in response to car speed. It is understood that other sensors (e.g., position sensor, accelerometers) may be used for controlling motion of car 12.
A motor 36 (e.g., a spindle motor) is positioned at a first end of the magnetic screw 30 and rotates the magnetic screw 30 about its longitudinal axis in response to control signals from controller 20. In an exemplary embodiment, the outer diameter of motor 36 is less than the outer diameter of magnetic screw 30 to allow the motor 36 to travel within a cavity in stator 16. A brake 38 (e.g., a disk brake) is positioned at a second end of the magnetic screw 30 to apply a braking force in response to control signals from controller 20. In an exemplary embodiment, the outer diameter of brake 38 is less than the outer diameter of magnetic screw 30 to allow the brake 38 to travel within a cavity in stator 16. In an exemplary embodiment, brake 38 may be a disk brake. Further, brake 38 may be part of motor 36 in a single assembly. Magnetic screw assembly 18 is coupled to the car 12 through supports, such as rotary and/or thrust bearings.
A second magnetic screw assembly 18′ may be positioned on an opposite side of car 12. Components of the second magnetic screw assembly 18′ are similar to those in the first magnetic screw assembly 18 and labeled with similar reference numerals. Magnetic screw 30′ has a first permanent magnet 32′ of a first polarity positioned along a non-linear (e.g., helical) path along a longitudinal axis of the magnetic screw 30′. A second permanent magnet 34′ of a second polarity (opposite the first polarity) is positioned along a non-linear (e.g., helical) path along a longitudinal axis of the magnetic screw 30′.
The pitch direction of the helical path of the first permanent magnet 32′ and the second permanent magnet 34′ is opposite that of the helical path of the first permanent magnet 32 and the second permanent magnet 34. For example, the helical path of the first permanent magnet 32 and the second permanent magnet 34 may be counter clockwise whereas the helical path of the first permanent magnet 32′ and the second permanent magnet 34′ is clockwise. Further, motor 36′ rotates in a direction opposite to the direction of motor 36. The opposite pitch and rotation direction of the magnetic screw assemblies 18 and 18′ balances rotational inertia forces on car 12 during acceleration.
A backup propulsion assembly 40 is coupled to car 12 to impart motion to car 12 in overload situations. The backup propulsion assembly 40 includes a mechanical screw 42 that normally travels within stator 16 without coacting with stator 16 when the backup propulsion assembly 40 is inactive. Upon a fault, the backup propulsion assembly 40 is active and the mechanical screw 42 is positioned to engage the stator 16. Rotation of the mechanical screw 42 imparts motion to car 12.
Stator 16 may be formed using a variety of techniques. In one embodiment, stator 16 is made from a series of stacked plates of a ferrous material (e.g., steel or iron). As shown in
The outer surfaces of body 50 may be smooth and provide a guide surface for one or more stiff guide rollers 60. Guide rollers 60 may be coupled to the magnetic screw assembly 18 to center the magnetic screw 30 within stator 16. Centering the magnetic screw 30 in stator 16 maintains an airgap between the magnetic screw 30 and poles 56. A lubricant or other surface treatment may be applied to the outer surface of body 50 to promote smooth travel of the guide rollers 60.
One feature that allows the car 12 and magnetic screw assembly 18′ to move from stator 16 is the arc of the stator 16. In an exemplary embodiment, the stator 16 occupies an arc less than or equal to about 180° (e.g., about)165°), as shown in
A support 120 is used to support car 12 in the transfer station. Support 120 may be spring biased to deflect under car 12, once car 12 passes support 120. Support 120 may be controlled by an actuator and driven into place once car 12 passes a certain point in the transfer station.
An exemplary method for lateral transfer of car 12 in transfer station 70/72 is described with reference to
At 206, one or both of magnetic screw(s) 30, 30′ are turned another half turn, to align permanent magnets 32 and 34 on magnetic screw with similar polarity stator magnets 110 on stator 16. This creates a repulsive force between one or both of magnetic screw(s) 30, 30′ and the stator permanent magnets 110 in the direction, A. Car 12 can then be moved horizontally or laterally by transfer station components at 208. Due to the repulsive force between one or both of magnetic screw(s) 30, 30′ and the stator permanent magnets 110, it is easier for the transfer station to separate car 12 from stator 16.
To reinstall car 12 to the hoistway 14, the reverse process may be followed. That is, one or both of magnetic screw(s) 30, 30′ are turned a half turn, to align permanent magnets 32 and 34 on magnetic screw with opposite polarity stator magnets 110 on stator 16. Car 12 can then be loaded onto supports 120 in hoistway 14, while the attraction between one or both of magnetic screw(s) 30, 30′ and the opposite polarity stator magnets 110 aids in moving car 12 towards the stator. Magnetic screw assemblies 18, 18′ are used to raise car 12 off support(s) 120 and the supports are retracted.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. While the description of the present invention has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications, variations, alterations, substitutions, or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. Additionally, while the various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as being limited by the foregoing description, but is only limited by the scope of the appended claims.
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PCT/US2015/054207 | 10/6/2015 | WO | 00 |
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WO2016/060888 | 4/21/2016 | WO | A |
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