WO2010086591A2

WO2010086591A2 - Safety device for a passenger transportation system

Info

Publication number: WO2010086591A2
Application number: PCT/GB2010/000116
Authority: WO
Inventors: Michael Godwin
Original assignee: Michael Godwin
Priority date: 2009-01-27
Filing date: 2010-01-26
Publication date: 2010-08-05
Also published as: WO2010086591A3; GB0901342D0

Abstract

A passenger transportation system (100) comprising a cabin assembly and a chassis assembly (200), wherein the chassis assembly is arranged to be driven in an upwards direction, the chassis assembly comprising at least one brake (203), the cabin assembly being detachable from the chassis assembly when the at least one brake is applied when the cabin assembly is moving upwards, wherein the cabin assembly comprises an emergency drive mechanism for reducing the upwards deceleration of the cabin assembly when the at least one brake is applied.

Description

Safety Device for a Passenger Transportation System

Field of the invention

The present invention relates to a passenger transportation system and a method of operating a passenger transportation system. It further relates to a cabin assembly and a drive assembly for use in a passenger transportation system. It further still relates to a method and apparatus for a safety device for a passenger transportation system.

Background

Most lifts (also referred to as "elevators") are suspended by ropes and generally have a counterweight. This arrangement means that when an emergency stop occurs the fail safe brake is applied to the traction sheave and not directly on the lift car. (The traction sheave is the pulley that drives the rope that the lift and counterweight are suspended from.) Under such circumstances the lift car continues to be connected to its counterweight, and the combination of appropriate braking force and the stored kinetic energy in both the moving lift car and counterweight ensure that the upwards deceleration of the lift is always substantially less than 1 g (where g is the acceleration due to gravity).

It is important to maintain a maximum upwards deceleration of a lift to be less than 1 g. This is particularly important when a lift performs an emergency stop when moving upwards. Upwards deceleration of greater than 1 g would result in the passenger's feet leaving the floor of the lift. Ensuring upwards deceleration is less than 1 g maintains reasonable passenger comfort.

A known lift system operates uses linear electric motors and thus is not suspended by ropes nor does it have a counterweight. Such a lift system may be referred to as a ropeless gearless lift. The brakes of a lift must be able to apply a braking force of greater than 1 g in order to decelerate the lift when performing an emergency stop when moving downwards.

When brakes are applied to a ropeless gearless lift moving upwards the deceleration of the lift is far greater than a conventional roped lift because there is no counterweight. When brakes are applied to a ropeless gearless lift when it is moving upwards at speed, the lift cabin will be subjected to a deceleration of 1 g due to gravity and a further force greater than 1 g from the brakes, hi such a scenario the lift will be subject to a deceleration in excess of 2 g. Under such deceleration a passenger's feet would leave the floor of the lift, and the passengers' heads could even hit the ceiling of the lift cabin. This is clearly unacceptable.

It is therefore an aim to provide a passenger transportation system which limits the upwards deceleration a lift cabin experiences, particularly in the case of a lift performing an emergency stop when moving upwards at speed.

Although the embodiments described herein give the example of passenger discomfort, it should be noted that a lift carrying a cargo load would also suffer if subjected to a deceleration greater than 1 g because the load would be subject to impacts with the floor and/or the ceiling of the lift cabin. Such impacts could cause damage to any of: the cargo, any personnel travelling with the cargo, the lift cabin or the lift drive mechanism.

Summary

There is provided a passenger transportation system comprising a cabin assembly and a chassis assembly, wherein the chassis assembly is arranged to be driven in an upwards direction, the chassis assembly comprising at least one brake, the cabin assembly being detachable from the chassis assembly when the cabin assembly is moving upwards and when the at least one brake is applied, wherein the cabin assembly comprises an emergency drive mechanism for reducing the upwards deceleration of the cabin assembly when the at least one brake is applied.

Moving in an upwards direction may be movement in a direction having a positive component of vertical upwards velocity.

The emergency drive mechanism may be a multifunction motor. The emergency drive mechanism may be powered by an on-board storage element. The on-board storage element may be a capacitor. The capacitor may be a super capacitor or an ultra capacitor. The multifunction motor may operate as a retarder. The retarder may slow the descent of the cabin assembly as it descends back to the chassis assembly.

The chassis may comprise buffers to provide energy absorption during connection of cabin assembly and chassis assembly. The chassis assembly may comprise a latch for allowing detachment of the cabin assembly from the chassis assembly. The latch may be released upon application of the at least one brake when the cabin assembly is moving upwards. The latch may be inertia operated when the chassis assembly is subjected to upward deceleration greater than Ig.

The retarder may also slow the descent of the combined cabin assembly and chassis assembly. Power generated by the retarder may be used to maintain cabin services and power to allow disengagement of the at least one brake. Typically, the brakes of a lift are actuated by a spring and solenoid combination that causes the brakes to be applied when power is not supplied to the solenoid. Where the retarder is used to slow the descent of the combined cabin assembly and chassis assembly, a large buffer may be provided at the lowest point of the passenger transportation system for receiving the chassis and cabin assembly, and bringing them to a controlled stop.

There is also provided a method of operating a passenger transportation system, the passenger transportation system comprising a cabin assembly and a chassis assembly, wherein the chassis assembly is arranged to be driven in an upwards direction, the method comprising: applying a brake on the chassis assembly; detaching the cabin assembly from the chassis assembly; engaging a drive mechanism on the cabin assembly for reducing the upwards deceleration of the cabin assembly when the at least one brake is applied.

There is further provided a passenger transportation module comprising a cabin assembly and a chassis assembly, wherein the chassis assembly is arranged to be driven in an upwards direction, the chassis assembly comprising at least one brake, the cabin assembly being detachable from the chassis assembly when the at least one brake is applied when the cabin assembly is moving upwards, wherein the cabin assembly comprises an emergency drive mechanism for reducing the upwards deceleration of the cabin assembly when the at least one brake is applied. There is further still provided a track for a passenger transportation system comprising: at least one main rail for supporting a passenger transportation module; at least one stator rail for cooperating with permanent magnets of a passenger transportation module to provide drive to the passenger transportation module; a series of switches for providing power to the at least one stator rail; and at least one magnet rail for cooperation with a multifunction motor of a passenger transportation module.

Embodiments provide a system in which the deceleration of a cabin assembly is limited by the application of an emergency drive motor to prevent the cabin assembly from stopping too quickly. The chassis assembly carries a brake that causes it to stop quickly in the event of an emergency, such as power failure. In order to allow the emergency drive motor to prevent the cabin assembly from stopping too quickly, the cabin assembly separates from the chassis assembly.

The emergency drive motor may be a multi-function motor that can also operate as a retarder. The retarder is used to allow a slow descent of the cabin assembly back to the chassis assembly, which stopped much sooner due to the brake. Small buffers on the chassis assembly allow for reconnection to the cabin assembly with reduced force. A latch re-engages and connects the cabin assembly to the chassis assembly. The latch includes electrical contacts to electrically connect the cabin assembly to the chassis assembly.

The brake is spring operated and so fail safe. In normal operation power is supplied to a solenoid to disengage the brake. In a power failure emergency, the solenoid loses power and the brake is applied. After an emergency stop, once the cabin assembly and chassis assembly have reconnected, an onboard power supply provides power to the brake to disengage it. Once the combined cabin and chassis assembly start descending, under retardation by the multifunction motor, power from the retarder is used to keep the brake disengaged.

In order to ensure that the retarder is slowing the cabin, power from an onboard supply may be applied to disengage the brake for a very short period of time, enough time for the chassis and cabin assembly to begin falling. If the retarder does not function correctly and fails to provide power to the brakes they reengage and prevent the chassis and cabin assembly from falling too far or too fast.

The combined cabin and chassis assembly descend to the lowest point of the track upon which the combined cabin and chassis assembly runs, where a large buffer is provided to limit the force in bringing the combined cabin and chassis assembly to a complete stop.

Brief Description of the Drawings

Examples of a passenger transportation system disclosed herein will be described with reference to the following drawings, in which: figure IA shows a passenger transportation system having two curved tracks with passenger transportation modules shown at various positions along each track; figure IB shows a close-up view of a passenger transportation module from figure IA on the track; figure 2A shows a lift lobby incorporating the passenger transportation system; figure 2B shows a cutaway of figure 2A with the passenger transportation modules of the passenger transportation system visible; figure 3 shows a passenger transportation module on a track in more detail; figure 4 shows a cabin assembly on a track but separated from the chassis assembly, also on the track; figure 5 shows a cross section and perspective view of the track; figure 6 shows a cross section and perspective view of the track with a passenger transportation module in place; figure 7 shows a part cutaway of the track giving a view of the chassis assembly; figure 8 shows the view of figure 7 but from below; figure 9 shows a track with a chassis assembly in place and a semi transparent cabin assembly; and figure 10 shows an annotated graph of the velocity of both the cabin assembly and the chassis assembly after an emergency stop when the passenger transportation module was travelling in the up direction.

Detailed Description The passenger transportation system comprises at least one passenger transportation module arranged to run on at least one track. The passenger transportation module comprises a cabin assembly and a chassis assembly.

The cabin assembly comprises: a cabin, in which passengers or cargo can be carried; an onboard energy storage element, which may be a capacitor; and a multifunction motor.

The multifunction motor (or multifunction motor/generator) can operate as a motor, a retarder, and as a generator. The multifunction motor is permanently fixed to the cabin assembly. In these three modes of operation the multifunction motor cooperates with at least one permanent magnet track integrated into the track on which the passenger transportation module runs.

The multifunction motor is used as a motor to provide an emergency drive mechanism to prevent the cabin assembly from decelerating too quickly in an upwards direction. The power to drive the motor is provided by an onboard energy storage element. The onboard energy storage element is capable of delivering a large amount of power to drive the cabin assembly during an emergency stop, but is only required to do so for a short period of time, sufficient to allow the cabin assembly to decelerate comfortably. The onboard energy storage element may be a capacitor, hi an embodiment an onboard battery is charged by the multifunction motor operating as a generator, and the onboard battery is used to maintain charge of an onboard capacitor that is used to drive the multifunction motor as a motor in an emergency stop situation.

Operating as a motor, the multifunction motor produces a high peak force without saturating the magnetic circuit. This is done by supplying to it a very high voltage from the onboard capacitor. To obtain the very high voltage in the onboard capacitor, appropriate conversion circuitry is used powered by the onboard battery. This ensures that at any instant the current in the winding of the multifunction motor is at right angles to the flux in the air gap between opposing magnet rows of a magnet track. Sufficient power is delivered to the multifunction motor to ensure a comfortable up stop deceleration of the passenger transportation module. The onboard capacitor supplies approximately constant current and under this condition the voltage supplied by the capacitor falls substantially linearly as the capacitor discharges between its operational limits. The onboard capacitor is discharged until the cabin assembly begins to move back down the track, at which point the multifunction motor is switched from motor operation to retarder operation.

When the multifunction motor operates as a retarder, it is connected to a tuned circuit which results in a substantially constant retarded descent speed. The retarded descent speed is selected to be sufficiently low such that the cabin assembly can be brought to a stop upon impact with a buffer without significantly sharp deceleration and without significant passenger discomfort.

The multifunction motor may also operate as a generator during normal operation of the passenger transportation module. This provides power to the onboard systems such as cabin lighting, door motor operation, and air conditioning. This may also provide power to the solenoids so as to disengage the emergency brakes. Also, the generator may provide power to top up the charge stored in onboard energy storage elements such as a battery or a capacitor. The multifunction motor may be arranged to operate as a generator only when the passenger transportation module is descending. In such a circumstance the onboard battery would provide power to the onboard systems during ascent of the passenger transportation module.

The multifunction motor is sized to satisfactorily perform the most demanding of the above functions, which is that of operation as a retarder. For redundancy purposes the multifunction motor comprises a plurality of independent windings which cooperate with the at least one permanent magnet track. The multifunction motor remains attached to the cabin assembly even when the cabin assembly detaches from the chassis assembly. In the embodiment illustrated the multifunction motor comprises two 3 m long sections and this is sufficient to safely retard a gross mass of 5000 kg. To meet these specifications the multifunction motor has an efficient magnetic design that gives a high figure of merit. The figure of merit is the thrust output divided by the square root of the input power. This is achieved by having a double sided permanent magnet track; that is each permanent magnet track comprises two rows of magnets arranged either side of a gap, the gap for receiving the multifunction motor. The magnets in each row are arranged with alternating poles, and opposing magnets in each row are arranged with opposing poles facing each other. The multifunction motor is held in position in the gap, with appropriate spacing from each row of magnets, by motor guide wheels. The motor guide wheels are arranged to run against the substrates that support each row of magnets.

The multifunction motor is arranged to operate as a retarder by connecting a tuning capacitor across the electrical terminals of the windings of the multifunction motor. This allows a substantially constant speed of descent under the influence of gravity. In such an arrangement the multifunction motor is part of a tuned circuit operating near resonance where the circulating current is magnified so providing sufficient flux in the air gap to generate a force to counteract the weight of the passenger transportation module. This arrangement permits the passenger transportation module to accelerate for half a pole pitch, the pole pitch being that of the permanent magnet track and approximately 1 cm. A tuning capacitor is selected such that resonance occurs at a descent speed acceptable to the energy absorbing buffers of both the chassis assembly, and also the buffers provided at the lowest point of travel of the passenger transportation module when the multifunction motor is retarding both the passenger transportation module and its maximum permitted load. In the embodiment such a descent speed is 1.5 m/s.

When operating as a generator not all of the windings of the multifunction motor may be required to generate sufficient power required by the passenger transportation module during operation. In an embodiment three windings are used to generate a three phase power output which is passed through an invertor to generate a DC voltage suitable for charging the onboard storage elements. The multifunction motor will only produce power as a generator when the passenger transportation module is moving. Therefore the multifunction motor is used to charge an onboard battery which in turn provides power to the onboard systems even when the passenger transportation module is not moving. Sufficient windings of the multifunction motor are used as a generator such that enough power is generated to power the onboard systems and charge the onboard battery when the passenger transportation module is travelling at moderate speed, which is 3 m/s.

The multifunction motor may be arranged to generate power either only when the module is descending or both when it is ascending and when it is descending. When the multifunction motor is not operating as a generator, power is supplied to the module's onboard systems by the onboard battery.

The chassis assembly comprises: the main drive components, a latch, buffers, and at least one brake. The main drive components comprise permanent magnets and guide wheels, the permanent magnets cooperate with a stator on the track to form a linear motor. The guide wheels ensure optimal spacing is maintained between the magnets and the stator. The latch is used to connect the chassis assembly to the cabin assembly. The latch includes electrical contacts for connecting the two assemblies. In an alternative embodiment the electrical contacts between the two assemblies are provided by a mechanism independent of the latch.

The chassis assembly includes at least one brake. The brake can be used to maintain the position of the passenger transportation module when it is stationary, for example to let passengers on and off. In an emergency situation the brake may be applied when the passenger transportation module is moving, in order to bring it to a controlled emergency stop.

The track comprises main rails for supporting and guiding the passenger transportation module. The track further comprises a stator part of the linear motor for normal driving of the passenger transportation module. The track has at least one magnet track for cooperation with the multifunction motor. The track also has switches for providing power to the stator. The track yet further comprises guide rails in which the guide wheels of the chassis assembly run.

Figures IA and IB give an overview of the passenger transportation system. A curved track 300 is shown which requires the orientation of the cabin 101 relative to the cabin assembly to change. This is done by way of a rope 102 wound round the cabin and a motor 103 which can be driven to pull the rope 102 in either direction, tilting the cabin 101 appropriately. The motor 103 is controlled in response to the output of a tilt sensor attached to or in the cabin. As an alternative the weight of the cabin 101 can be relied upon to keep the cabin 101 upright. Damping may still be provided to limit oscillation of the cabin 101. Where a motor 103 controls the tilt of the cabin 101, under loss of power the drive connection to the motor 103 can be disconnected and the weight of the cabin 101 relied upon to keep it upright.

Figure 2 shows a lift lobby incorporating the passenger transportation system, which can be tailored to appear to passengers as a conventional lift (elevator) system.

Figure 3 shows a passenger transportation module on a track 300 in more detail. At the base of the cabin assembly 100 part of the chassis assembly 200 is shown including two buffers 201, the latch 202, and two emergency brakes 203 (which engage with the main rail).

Figure 4 shows a cabin assembly 100 on a track 300 but separated from the chassis assembly 200. Wheels 104 of the cabin assembly 100 are shown running on main rails 301 of the track 300. The full length of the chassis assembly 200 is visible. The chassis assembly 200 is shown with two emergency fail safe brakes 203 and four articulated magnet sections 240 of the drive motor. Guide wheels 241 are provided between each articulated magnet section 240 to accommodate variation in curvature of the track 300. An onboard battery 110 and an onboard capacitor 112 are shown mounted to the base of the chassis assembly 100.

Figure 5 shows a cross section and perspective view of the track 300, including: two main rails 301, two strips of stator switching relays 302, six guide rails 303, three stators 304, two out of four magnet tracks 305 are visible. A brush strip 306 is provided over the magnet tracks 305 to help keep them clean. Guide rails 307 run either side of the stators 304. Further guide rails 308 run along upper and lower edges of the stators 304. Figure 6 shows a cross section and perspective view of the track 300 with a passenger transportation module in place. The brakes 203 are shown engaged with the rail 301. The wheels 104 of the chassis assembly 100 are shown supporting the weight of the cabin assembly 100 on the main rails 301. The guide wheels 241 run in guide rails 307 to maintain vertical position of the articulated magnet sections 240 relative to the stators 304. Further guide wheels 242 run against the further guide rails 308 to maintain horizontal position of the articulated magnet sections 240 relative to the stators 304. Two multifunction motors 120 of the cabin assembly 100 run between pairs of magnet tracks 305.

Figure 7 shows a part cutaway of the track giving a view of the chassis assembly 200 in more detail. Two adjacent articulated magnet sections 240a and 240b are shown, adjacent articulated magnet sections can articulate at their connection. A guide wheel 241a is provided on either magnet section 240a or 240b adjacent the other of the magnet sections. The independence of the chassis assembly 200 is apparent. The chassis assembly 200 has 12 articulated magnet sections 240, and these are driven by magnetic fields generated by power applied to the stators 304. Power is applied to the stators 304 by a plurality of stator switching relays 302.

Figure 8 shows the view of figure 7 but from below, giving a more detailed view of the articulated magnet sections 240, the magnets mounted thereon, the guide wheels 241 and the further guide wheels 242. The guide wheels 241 and the further guide wheels 242 maintain an air gap between the magnets of the chassis assembly and the stator 304 of the track 300. The further guide wheels 242 in particular operate to resist the magnet attraction of the magnets of the articulated magnetic sections 240 to the stator 304.

Figure 9 shows a track with a chassis assembly 200 in place and a semi transparent cabin assembly 100, and in particular the engagement of the latch 202 with the cabin assembly 100. The latch 202 is inertia operated such that the cabin is released if the chassis assembly 200 is subjected to a deceleration greater than 0.5 g. When the latch releases the cabin assembly 100, full power is applied to the multifunction motors 120 to allow the upward velocity of the cabin assembly 100 to be reduced at a deceleration less than 0.3 g. Figure 10 shows an annotated graph of the velocity of both the cabin assembly 100 and the chassis assembly 200 after an emergency stop when the passenger transportation module was travelling in the up direction at a typical ascent speed of 6 m/s. As explained above the emergency brake will result in a deceleration of at least 2 g when the passenger transportation module is travelling upwards and the emergency brakes 203 are applied. Accordingly, where g is approximately 10 m/s , the chassis assembly 200 will come to a complete stop in about 0.3 seconds. With power applied to the multifunction motors 120, the cabin assembly 100 can continue upwards and decelerate at a lower rate of say 0.2 g, and so take around 3 seconds to stop. The cabin assembly 100 will then begin to fall under the influence of gravity, and at this stage the multifunction motor 120 switches from motor operation to retarder operation, whereupon it retards the motion of the cabin assembly 100 causing it to fall at a very low fixed velocity until it meets the buffers 201 of the chassis assembly 200, which decelerate the cabin assembly 100 from its very low fixed velocity to come to zero and the latch 202 re-engages locking the cabin assembly 100 to the chassis assembly 200. The time axis of the graph in figure 10 is compressed in the region where the velocity of the cabin assembly is negative (downwards).

Once the cabin assembly 100 has been safely brought to a stop and re-engaged with the chassis assembly 200, the passenger transportation module can begin a controlled decent to, say, the ground floor of the building, under control of the multifunction motors 120 operating in retarder mode.

In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the scope of the technique. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims

1. A passenger transportation system comprising a cabin assembly and a chassis assembly, wherein the chassis assembly is arranged to be driven in an upwards direction, the chassis assembly comprising at least one brake, the cabin assembly being detachable from the chassis assembly when the at least one brake is applied when the cabin assembly is moving upwards, wherein the cabin assembly comprises an emergency drive mechanism for reducing the upwards deceleration of the cabin assembly when the at least one brake is applied.

2. A passenger transportation system according to claim 1, wherein moving in an upwards direction is movement in a direction having a positive component of vertical velocity.

3. A passenger transportation system according to claim 1 or 2, wherein the emergency drive mechanism is a multifunction motor.

4. A passenger transportation system according to any preceding claim, wherein the emergency drive mechanism is powered by on-board storage element

5. A passenger transportation system according to claim 4, wherein the on-board storage element is a capacitor.

6. A passenger transportation system according to claim 5, wherein the capacitor is a super capacitor or an ultra capacitor.

7. A passenger transportation system according to claim 3, 4, 5 or 6, wherein the multifunction motor can operate as a retarder.

8. A passenger transportation system according to claim 7, wherein the retarder slows the descent of the cabin assembly as it descends back to the chassis assembly.

9. A passenger transportation system according to any preceding claim, wherein the chassis assembly comprises buffers to provide energy absorption during connection of cabin assembly and chassis assembly.

10. A passenger transportation system according to any preceding claim, wherein the chassis assembly comprises a latch for allowing detachment of the cabin assembly from the chassis assembly.

11. A passenger transportation system according to claim 10, wherein the latch is released upon application of the at least one brake when the cabin assembly is moving upwards.

12. A passenger transportation system according to claim 11, wherein the latch is inertia operated and released when the chassis assembly is subjected to upward deceleration greater than 1 g.

13. A passenger transportation system according to any of claims 7 to 12, wherein the retarder also slows the descent of the combined cabin assembly and chassis assembly.

14. A passenger transportation system according to claim 13, wherein power generated by the retarder is used to maintain disengagement of the at least one brake.

15. A passenger transportation system according to any preceding claim, wherein a buffer is provided at the lowest point of the passenger transportation system for receiving the chassis and cabin assembly.

16. A method of operating a passenger transportation system, the passenger transportation system comprising a cabin assembly and a chassis assembly, wherein the chassis assembly is arranged to be driven in an upwards direction, the method comprising: applying a brake on the chassis assembly; detaching the cabin assembly from the chassis assembly; engaging a drive mechanism on the cabin assembly for reducing the upwards deceleration of the cabin assembly when the at least one brake is applied.

17. A passenger transportation module comprising a cabin assembly and a chassis assembly, wherein the chassis assembly is arranged to be driven in an upwards direction, the chassis assembly comprising at least one brake, the cabin assembly being detachable from the chassis assembly when the at least one brake is applied when the cabin assembly is moving upwards, wherein the cabin assembly comprises an emergency drive mechanism for reducing the upwards deceleration of the cabin assembly when the at least one brake is applied.

18. A track for a passenger transportation system comprising: at least one main rail for supporting a passenger transportation module; at least one stator rail for cooperating with permanent magnets of a passenger transportation module to provide drive to the passenger transportation module; a series of switches for providing power to the at least one stator rail; at least one magnet rail for cooperation with a multifunction motor of a passenger transportation module.