Technical Field of the Invention

The present invention relates to a transportation system, and particularly but not exclusively to a transportation system for the movement of passengers and/or goods in a heightwise direction within a building. The invention also relates to a drive apparatus suitable for a transport system.

Background to the Invention

Multi- storey buildings are routinely provided with lifts (also known as elevators) for the movement of passengers and goods between floors. Most conventional lifts are suspended by cables in a lift shaft and generally have a counterweight. This limits the number of lift cars per shaft, usually to one.

This limitation impairs the efficiency of a building, by limiting the floor area of the building that may be put to use, in particular let or sold. Indeed, transportation systems for moving passengers and goods between floors are often the largest space taking element of a high rise building core.

It is an object of embodiments of the present invention to provide an alternative, improved, transport system suitable for use in buildings which enables more floor space to be made available for use than with existing systems.

Summary of the Invention According to a first aspect of the present invention there is provided a transportation system comprising a track structure supporting at least two substantially parallel tracks along each of which cars may travel, the track structure comprising at least two rotatably connected sections enabling the two sections to be rotated relative to one another so that a track of one section may be aligned with either track of the other section enabling a car to be transferred from one track to the other.

Enabling a car to be transferred from one track to another enables a two track system to be used as if it were a continuous loop with cars travelling in only one direction on a given track, for example up or down. Thus more than one car can be accommodated on a single track increasing space efficiency over a cable hauled lift system.

The two substantially parallel tracks may be supported on opposite sides respectively of the track structure. The track structure may extend in a substantially vertical direction and comprise upper, mid and lower sections. The upper and lower sections may be rotated relative to the mid section.

The two sections may be connected to rotate about an axis substantially parallel to the direction in which the track extends. Alternatively, the two sections may be connected to rotate about an axis substantially perpendicular to the direction in which the track extends.

One or more cars may be mounted on the track structure, each car and/or the track structure may comprise drive means arranged to propel the car along the track structure. In one arrangement a rack and pinion drive is used. In another, a linear motor is used.

According to another aspect of the present invention there is provided a transportation system comprising a first, upright, track structure comprising one or more tracks on which a car may travel and a second track structure comprising at least one track on which a car may run, the second track structure being rotatably supported about a horizontal axis and arranged so that when in an upright orientation at least one track of the first structure is aligned with a track of the second track structure so that a car may pass along the track from one structure to the other.

The transportation system may further comprise a horizontal track structure having at least one track on which a car may run and be arranged so that when the pivotally mounted track structure is in a substantially horizontal orientation at least one track of the horizontal track structure is aligned with a track of the pivotally mounted track structure so that a car may pass along the track from one structure to the other.

The upright and pivotally mounted track structures may each comprise two tracks mounted on opposite sides respectively of the structure, and when the pivotally mounted track structure is in an upright configuration the two tracks of the pivotally mounted structure are respectively aligned with the two tracks of the upright track structure.

In use the transport systems may be used by providing a car on a first track of one section of the track structure, moving the car along the track until it passes onto the other section of the track structure, rotating the two sections of the track structures relative to one another so that the track on which the car is mounted becomes aligned with a second track of the first section of the track structure and moving the car along the track onto the second track of the first section.

The transport systems are particularly suited for installation in buildings to provide transport between floors. According to another aspect of the present invention there is provided a drive apparatus suitable for driving a car of a transport system comprising a lantern pinion engaged with a rack wherein at least one of the rack or rods of the lantern pinion are formed from or coated with a plastics material. The rack may be formed from metal and the rods of the lantern pinion may be formed from or coated with a plastics material. Preferably they are formed from a fibre reinforced plastics material, particularly PEEK. The rods of the lantern pinion may be free to rotate. The lantern pinion is preferably driven directly by a synchronous permanent magnet rotary electric motor. Such a motor is conveniently formed from three curved, double sided, single phase permanent magnet synchronous linear electric motors. Each curved linear motor may comprise a single winding.

Detailed Description of the Invention

In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 is a cross-section through upper and lower ends of a vertical shaft in a building housing a transportation system according to a first embodiment of the invention; Figure 2 is a plan view of the shaft of figure 1 taken from line II-II of figure

1 ;

Figure 3 is a plan view of the lower end the shaft of figure 1 showing a car in two different positions;

Figure 4 is an enlarged view of a car of the transport system of figure 1 , mounted on the track structure;

Figure 5 is an enlarged side view of detail of the drive apparatus for the car of the transportation system of figure 1 ; Figure 6 is front view of the drive apparatus of figure 5;

Figure 7 is a plan view of a part of a linear motor stator used in an alternative embodiment of the transport system;

Figure 8 is a view similar to figure 2 of the embodiment of figure 7, but only showing one side of the track structure; and

Figure 9 is a cross-section through a vertical shaft in a building housing a transportation system according to a second embodiment of the invention.

Referring to figures 1 to 6, a transportation system is housed in a shaft 1 which extends in a generally vertical direction between floors of a building. The transportation system comprises a track structure comprising an elongate body 2 of broadly rectangular cross-section. The body extends substantially vertically in the shaft and supports substantially identical tracks on its opposite larger faces. Each track comprises two parallel spaced apart rails 3 with a rack 4 mounted on a third H or T- section rail 4a extending approximately mid- way between, and parallel to, the rails. The track structure defines hollow spaces 5 within the structure, which may serve as conduits or cable trays. The track structure, rails and rack are all formed from steel, or some other suitable metal, alloy or composite material.

The track structure is formed by three sections: upper and lower end sections and a mid section. The upper and lower end sections are connected to the mid section by way of thrust bearings 6, and at their opposite ends they are mounted to the ends of the shaft via further thrust bearings. The mid section of the structure is mounted directly or indirectly to a side wall of the shaft. Thus the upper and lower end sections of the track structure may rotate relative to the midsection, about an axis which is substantially parallel to the vertical axis of the track structure. At each end of the track structure a drive motor and gearbox 7 is provided, operative to rotate the associated end section of the track structure relative to the mid section. A locking means (not shown) is provided to lock the end sections of the track structure relative to the mid section when the two sections are appropriately aligned.

In the region of the end sections of the track structure 2 the shaft is enlarged to one side of the track structure in a semi-circular fashion, as shown in figure 3. Elsewhere the shaft is generally rectangular in cross-section.

Although not shown, it is envisaged that intermediate rotatable sections could be provided in the mid section of the track structure if desired.

Passenger cars 8 fitted with doors 8a on opposite sides are mounted for movement along the track structure. Each car 8 is provided with wheels 4b disposed on both sides of the central rail 4a mounted on the track structure and which enable the cars to be guided up and down the track structure along the rails. Each car 8 is also provided with a drive system which propels the car along the track structure by interaction with the rack. Guide wheels 3 a interact with the outer rails 3 to stabilise the car 8.

The drive system of each car comprises two separate electric motors 9 directly driving respective lantern pinions 10 which engage with the rack 4.

Each electric motor 9 is a triple layered, double sided permanent magnet synchronous motor, formed from three 120 degree curved lengths of a single phase curved linear motor stator mounted together to form an annular stator and rotor approximately one meter in diameter and arranged to drive the lantern pinion directly via a shaft. The stator 1 1 of each motor is formed by three single wound 120 degree lengths of linear motor stator. These are mounted together on a support 13 secured to the side of a car 8. Permanent magnets 12 are mounted to the inside of a cylindrical housing 14 connected to the shaft 15 connected to the lantern pinion 10. The lantern pinion comprises two spaced apart annular plates connected by twelve substantially parallel rods 17 evenly spaced around the plates.

This design of motor is able to provide a good power density and suitable torque characteristics to enable a relatively large pinion with a large pitch to be driven directly. This enables a car to be driven at an acceptable speed of about 2.5 mis with only a relatively low rotational speed of the motor, which helps to reduce noise.

The rods 17 of the lantern pinion 10 are formed from a carbon fibre reinforced self lubricating PEEK (polyether ether ketone), are rotatably mounted to the annular plates and are sized to engage with the appropriately shaped teeth of the rack. Using the PEEK material reduces the noise, as compared to using a metal, of meshing of the pinion with the steel rack 4. The self lubricating nature of the material avoids the need for lubrication and mounting the rods of the lantern pinion so that they may rotate further reduces friction and hence wear between the pinion and the rack.

The motors 9 of each car are controlled by way of an appropriately programmed field oriented controller. This controller provides a three phase alternating current power supply, one phase driving each of the motors' three windings. The frequency of the supply is varied to vary the speed of the motor, for example to gently accelerate a car from rest. The motors are driven in order to raise the cars 8 up the track structure, and configured to provide re- generative braking to control descent of the cars, the gravitational potential energy of the cars being converted to electrical energy which may be used to power cars travelling up the track structure, to power cars on other track structures or elsewhere. The controller is arranged to drive the two motors of each car so as to eliminate the effect of backlash in the rack and pinion.

In addition, the controller includes an emergency descent control. Each stator winding of the motor is connected to a respective capacitor by a normally closed contact of a contactor. In -the event of a power failure, or other emergency, the capacitors are automatically connected in series to an associated motor stator winding to form a resonant circuit. The capacitor is chosen so that the resonant frequency of the resonant circuit is such that electrical current generated in the circuit as the motor is rotated by a falling car serves to limit the speed of the car to a desired maximum, say 0.5 m/s.

In an alternative embodiment the cars are driven by a linear motor rather than a rack and pinion system. In this embodiment a linear motor stator formed from a series of stator sections 15, each comprising a single wound elongate coil, is mounted to the track structure 2 in place of the rack 4. The stator 15 extends over the entire length of the track structure. Figure 7 shows a small part of the stator, formed from three sections. Each section is about 30cm long.

Elongate permanent magnet assemblies 16 comprising multiple spaced apart magnets with a U-shaped cross sections are provided on the side of each car 8 which faces the track structure 2, and extend over most of the length of side of the car. The actual length of the magnet assembly for a particular car is selected so as to provide sufficient force to drive the car. When the car 8 is mounted on a track assembly the magnet assembly 16 is positioned over, and extends down each side of, the motor stator 15 forming a linear motor which can be used to drive the car along the track assembly.

Figure 8 shows a horizontal cross- section through half of a shaft containing a track structure, showing a single car 8. The arrangement is generally similar to that shown in figure 2, save that the rack on the track has been replaced with a linear motor stator 15, and the pinion and drive motors on the car have been replaced with a magnet assembly 16.

Electrical current in the linear motor stators can be controlled in essentially the same way as discussed above in relation to the rack and pinion system where, in effect, a linear motor has been curved to form a rotary motor. The car can be moved up and down the shaft by controlling current in the stator. The stator windings, in a default condition when no power is being applied, may be connected to a capacitor or capacitors to form a resonant circuit to provide controlled emergency descent.

The transportation system is used to transport passengers and/or goods between floors of the building. Cars 8 running on the track on one side of the track structure are driven upwards along the track, stopping as appropriate to allow for loading and/or unloading via the doors 8a. When a car reaches the top of the track structure, and is supported entirely on the upper end section of the track structure, the end section is rotated together with the car through 180 degrees relative to the mid section of the structure. The car moves through the semicircular part of the shaft. After rotation, the track supporting the car is aligned with the track on the opposite side of the track structure to that which it travelled up. The car now descends along this track, again stopping as appropriate for loading and unloading, until it reach the bottom end section of the track structure. This section is then rotated through 180 degrees allowing the car to ascend the opposite side of the track structure.

Thus cars can move around the track structure as it if were a continuous loop, using one track for upward movement and the other for downward movement. This allows more than one car to travel on the up and down tracks at the same time. As multiple cars can be accommodated one above the other in the same shaft the space efficiency of the system is far greater than with a conventional cable suspended lift.

Referring now to figure 9 there is shown an alternative embodiment of a transportation system, aspects of which could be combined with the systems described in relation to figures 1 to 8. In this embodiment a building is provided with connected vertical 20 and horizontal 21 shafts, and respective vertical and horizontal track structures 22 are mounted in those shafts. The vertical track structure is similar to that of the embodiments shown in figures 1 to 8 and supports tracks on two opposed faces. The horizontal track structure supports a single track on its upper face. The vertical track structure comprises a mid section and an upper end section. The upper end section is pivotally mounted with respect to an extension of the mid section of the structure, so that it can pivot about a substantially horizontal axis. The end section is mounted within a circular frame 23 driven by an electric motor 24 by way of an endless belt 25 which passes around the frame and a spindle of the motor. This enables a car running on one track of the track structure to be transferred to the track on the opposite side of the structure, by pivoting the end section of the track though 180 degrees. It also enables a car to be transferred from the vertical to horizontal tracks, or vice versa, by pivoting the end section through 90 degrees. With this embodiment it will be appreciated that as the end section of the track pivots, the orientation of a car supported on the end section will alter, Therefore, with this embodiment each car comprises a body to which a cabin is rotatably mounted. The cabin rotates to counteract rotation of the track section, and so remains upright with a substantially horizontal floor. The cabin may be rotated by a motor, or be weighted so that it is self-levelling. Thus this system is suitable for use with straight and curved tracks which follow sloping trajectories.

The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.