U.S. patent application number 11/490516 was filed with the patent office on 2007-03-01 for guideway activated magnetic switching of vehicles.
This patent application is currently assigned to MagneMotion Inc.. Invention is credited to Tracy M. Clark, Jesse Mendenhall, Richard D. Thornton.
Application Number | 20070044676 11/490516 |
Document ID | / |
Family ID | 37683806 |
Filed Date | 2007-03-01 |
United States Patent
Application |
20070044676 |
Kind Code |
A1 |
Clark; Tracy M. ; et
al. |
March 1, 2007 |
Guideway activated magnetic switching of vehicles
Abstract
A system for switching a transport vehicle comprising: a
guideway, a vehicle that moves along the guideway, and a magnetic
field source that creates a force on the vehicle to affect motion
in a desired direction at a switch. Once the vehicle has started
motion through the switch the guidance can be continued by use of
permanent magnets until the normal guidance system is effective.
The switching scheme can work with any suspension scheme, including
wheels and maglev, and can work with any lateral guidance scheme,
including horizontal guide wheels and magnetic guidance. The system
can be used with very closely spaced vehicles, such as with
Personal Rapid Transit, material handling, and elevators with
multiple cabs in the same shaft.
Inventors: |
Clark; Tracy M.; (Bedford,
MA) ; Mendenhall; Jesse; (Medford, MA) ;
Thornton; Richard D.; (Concord, MA) |
Correspondence
Address: |
NUTTER MCCLENNEN & FISH LLP
WORLD TRADE CENTER WEST
155 SEAPORT BOULEVARD
BOSTON
MA
02210-2604
US
|
Assignee: |
MagneMotion Inc.
Acton
MA
|
Family ID: |
37683806 |
Appl. No.: |
11/490516 |
Filed: |
July 19, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60701777 |
Jul 22, 2005 |
|
|
|
Current U.S.
Class: |
104/130.02 |
Current CPC
Class: |
E01B 25/12 20130101;
B61B 13/04 20130101; B60L 2200/26 20130101; B61B 13/08 20130101;
B61B 10/001 20130101; B60L 13/003 20130101 |
Class at
Publication: |
104/130.02 |
International
Class: |
B61B 13/08 20060101
B61B013/08 |
Claims
1. A system for switching of a vehicle, comprising: a first
switching structure disposed on the vehicle; a guideway for guiding
movement of the vehicle; and, a first electromagnet disposed on the
portion of the guideway for inducing a magnetic force between the
first electromagnet and at least a portion of the first switching
structure in the vicinity of the electromagnet, thereby directing
the vehicle at a switch point.
2. The system of claim 1, wherein the first switching structure
comprises at least one guide wheel.
3. The system of claim 1, wherein the first switching structure
comprises at least one plate.
4. The system of claim 1, wherein the first switching structure
comprises a ferromagnetic or paramagnetic material.
5. The system of claim 1, further comprising at least one permanent
magnet disposed on the portion of the guideway for inducing a
magnetic force between the permanent magnet and at least a portion
of the first switching structure in the vicinity of the permanent
magnet, thereby directing the vehicle at a switch point.
6. The system of claim 1, wherein the first electromagnet is
excited with alternating current.
7. The system of claim 1, wherein the vehicle comprises at least
two bogies, and the electromagnet induces a force between the
electromagnet and each of the bogies.
8. The system of claim 1, wherein the guideway is inclined or
vertical.
9. The system of claim 1, wherein the first electromagnet includes
at least one integral permanent magnet, for decreasing a power
requirement of the electromagnet or increasing the magnetic
force.
10. The system of claim 1, further comprising: a second switching
structure disposed on the vehicle; and a second electromagnet
disposed on an opposed portion of the guideway relative to the
first electromagnet for inducing a magnetic force between the
second electromagnet and at least a portion of the second switching
structure.
11. The system of claim 1, wherein the guideway comprises a first
guide rail for guiding movement of the vehicle, and the first
electromagnet is configured to induce a magnetic force between the
first guide rail and at least a portion of the first switching
structure in the vicinity of the first guide rail.
12. The system of claim 11, further comprising: a second guide rail
acting as a portion of the guideway, the vehicle configured to move
between the first guide rail and the second guide rail; a second
switching structure disposed on the vehicle, for engaging the
second guide rail; and, a second electromagnet for inducing a
second magnetic force between the second guide rail and at least a
portion of the second switching structure in the vicinity of the
second guide rail.
13. The system of claim 1, wherein the system is configured as an
elevator system.
14. The system of claim 13, wherein the guideway is configured as a
plurality of connected elevator shafts.
15. The system of claim 14, further comprising: a plurality of
elevator cabs configured to travel through the plurality of
connected elevator shafts.
16. The system of claim 15, wherein the plurality of elevator cabs
includes at least 4 elevator cabs.
17. A method of switching a vehicle, comprising: moving a vehicle
on a guideway; inducing a magnetic force between the vehicle and at
least a portion of the guideway situated laterally to the vehicle
by using an magnet disposed on the guideway, thereby directing the
vehicle at a switch point.
18. The method of claim 17, wherein inducing the magnetic force
includes interacting the magnet with a switching structure coupled
to the vehicle to induce the magnetic force.
19. The method of claim 17, wherein inducing the magnetic force
includes activating an electromagnet using alternating current.
20. The method of claim 17, wherein inducing the magnetic force
includes using a permanent magnet disposed on the guideway to
direct the vehicle at the switch point.
21. A system for switching of a vehicle, comprising: a switching
structure disposed on the vehicle; a guideway for guiding movement
of the vehicle; and, at least one magnet disposed on the portion of
the guideway for inducing a magnetic force between the at least one
magnet and at least a portion of the switching structure in the
vicinity of the at least one magnet, thereby directing the vehicle
at a switch point.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the filing date of
U.S. Provisional Application No. 60/701,777, filed Jul. 22, 2005,
the entire contents of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] This invention pertains to vehicular transport and, more
particularly, to methods and apparatus for the switching of
vehicles on a guideway.
[0003] All guideways must have means to choose between alternate
directions of travel. Conventional trains use switches with
mechanically movable rails that require several seconds to actuate
and have maintenance problems. Monorail trains and systems using
magnetic or air-cushion suspension typically require motion of
large sections of a guideway. Some automated people movers use
rubber-tired wheels for suspension and additional vertical-axle
wheels for guidance with switching done by moving sections of the
guideway.
[0004] For some applications, such as personal rapid transit or
material handling in a factory or elevators, it is important to be
able to operate with headways of only a few seconds. In these cases
it is not safe to use switches that require substantial motion of
sections of the guideway. So other ways to perform switching with
vehicle activated mechanisms have been devised. The most common way
to do this is to use mechanical wheels that interact with the
guideway to divert the vehicle or allow it to move straight at a
switch point as in U.S. Pat. Nos. 4,132,175 and 6,857,374. In some
cases the switching is done with switching-wheels that are mounted
on the vehicle but activated by the guideway as in U.S. Pat. No.
5,277,124. This makes it feasible to operate with short headway,
but now there is a reliability problem because the vehicle control
must be coordinated via guideway based controllers. With the
activating mechanism on the vehicle and the control on the guideway
the operation typically depends on a radio link with potential
interference problems. Additionally, the switching mechanisms are
mechanical which require maintenance and are vulnerable to
failure.
[0005] A number of improved mechanical switching schemes by using
magnetic forces have been proposed. There are two ways this has
been done: 1) Use electromagnets on the vehicle to create
attractive forces to ferromagnetic structures on the guideway as in
U.S. Pat. Nos. 3,763,788, 5,778,796 and 5,794,535; 2) Use coils on
the guideway that can be open circuited or short circuited so as to
create controllable repulsive force to a changing magnetic field as
in U.S. Pat. Nos. 3,994,236; 5,503,083, 5,517,924 and 5,865,123,
and 5,904,101. Neither of these methods has achieved wide success
and guideway-based mechanical mechanisms continuing to dominate
switch design.
[0006] For the special case when ElectroDynamic Suspension (EDS) is
used for magnetically suspended vehicles, it is possible to create
magnetic switching by shorting coils in one path and opening them
on the other path. This creates either a repulsive force or no
force on a moving magnet and variations on this idea are covered in
U.S. Pat. Nos. 3,994,236, 5,503,083, 5,517,924, 5,865,123 and
6,784,572. These techniques have the advantage of being guideway
activated and having no moving parts, but they do not work with
most types of suspension in use today.
[0007] In view of the foregoing, an object of the invention is to
provide improved methods and apparatus for vehicle switching. A
more particular object of the invention is to provide such methods
and apparatus as are applicable to vehicles on guideway.
[0008] A further object of the invention is to provide such methods
and apparatus as work with a variety of vehicle suspension and
guidance mechanisms.
[0009] A further object of the invention is to provide such methods
and apparatus as can be used, by way of non-limiting example, with
wheeled "road" vehicles, such as automobiles, buses and trucks, as
well as with (by way of further non-limiting example) "track"
vehicles, such as trains, trolleys, personal rapid transit vehicles
and baggage-carrying vehicles.
[0010] A still further object of the invention is to provide such
methods and apparatus as require fewer, if any, moveable mechanical
guidance components and that can be applied in applications
requiring relatively small headway.
SUMMARY OF THE INVENTION
[0011] The foregoing are among the objects attained by the
invention which provides, in some aspects, transportation and other
conveyance systems having magnets, e.g., electromagnets, on a
guideway to create forces, e.g., lateral forces, on a vehicle so as
to control the direction of vehicle travel at guideway switch
points, e.g., merge and/or diverge locations. The magnets can be
controlled, e.g., by a guideway-based controller that monitors the
position of the vehicle (and, for example, others on the guideway)
and controls the switching without the need to transmit control
signals to the moving vehicle itself.
[0012] In related aspects of the invention, the aforementioned
vehicle can have a normal guidance system, e.g., using either
wheels, magnets, air pressure or other force producing means.
However, according to aspects of the invention, switching is
initiated by the guideway-based electromagnets.
[0013] According to further related aspects of the invention, the
electromagnets are excited with DC or a low frequency AC so as to
create attractive forces to a ferromagnetic plate or wheel or other
switching structure, e.g., on the vehicle itself, or they can be
excited with higher frequency AC so as to create repulsive forces
to a conducting plate or wheel or other switching structure. It is
also possible to use both attractive and repulsive forces working
on opposite sides of the guideway to move the vehicle in the
desired direction.
[0014] According to further aspects of the invention the switching
is initiated by an electromagnet but once the vehicle moves a short
distance the switching is completed by means of one or more
permanent magnets located on the guideway. A permanent magnet can
keep the vehicle on the desired path until the normal guidance
mechanism is effective.
[0015] Methods and apparatus according to the invention are suited
for, among other things, guiding vehicles that are propelled by a
linear motor. With this propulsion scheme and guideway-based
magnetic switching the entire propulsion and control system can be
located on the guideway so the vehicle can be passive and there is
no need to transmit control signals to a moving vehicle.
[0016] These and other aspects of the invention are evident in the
drawings and in the claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] A more complete understanding of the invention may be
attained by reference to the drawings, in which:
[0018] FIG. 1 depicts a vehicle moving on a branching path with
motion that can be in either direction. In this example normal
guidance is by wheels and both electromagnets and permanent magnets
attract ferromagnetic wheels to achieve switching and guidance
through the switch area.
[0019] FIG. 2 depicts the same system as FIG. 1 except that the
vehicle is moving on the straight path.
[0020] FIGS. 3A and 3B shows a top view and side view,
respectively, of a suitable electromagnetic design for creating
attractive forces to a ferromagnetic wheel.
[0021] FIGS. 4A and 4B are the same as FIGS. 3A and 3B except that
the force is on a plate acting as the switching structure on the
vehicle.
[0022] FIGS. 5A and 5B show how permanent magnets can provide
attractive guidance forces when there is a break in the normal
guidance but the vehicle is already on the correct path. FIG. 5A
uses 3 magnets with different orientations, and FIG. 5B shows a
single magnet with ferromagnetic pole pieces used to focus the
flux. The 3-magnet configuration produces more guidance force but
may have a higher cost.
[0023] FIG. 6A shows field lines for an alternate magnet design in
which permanent magnets are used to augment the field produced by
the electromagnetic coils.
[0024] FIG. 6B shows field lines when the coil current is reversed
and there is very little force produced by the magnet design of
FIG. 6A.
DETAILED DESCRIPTIONS OF ILLUSTRATED EMBODIMENTS
Introduction
[0025] The invention described here is an outgrowth of earlier work
by the inventors hereof, described in U.S. Pat. No. 6,101,952, the
teachings of which are incorporated herein by reference. The design
discussed therein has been successfully used in a commercial
application, though improvements of lower complexity and cost are
always desirable. As will be appreciated from the discussion below,
the magnetic switching disclosed in that patent is modified herein
to work with a variety of suspension and guidance schemes, and to
use electromagnets on the guideway to create controllable forces on
the vehicle to force the vehicle to go in a specified direction at
a diverge and to operate safely at a merge
[0026] As shown in the drawings and discussed below, the
illustrated embodiment of the invention utilize magnetic forces for
diverting or merging vehicles at switch points on a guideway. The
switching is achieved by the interaction of a magnetic field
produced by one or more magnets on the guideway interacting with
one or more wheels or plates or other types of switching structures
on the vehicle to produce forces (e.g., lateral forces) on the
vehicle in the vicinity of merge or diverge locations, i.e.,
"switch points." The magnetic field can create either an attractive
force or a repulsive force and in some cases an attractive force on
one side can be augmented by a repulsive force on the other
side.
[0027] In general, the phrase "switching structure" is used herein
to refer to a one or more structures capable of interacting with
the magnetic field to create a force that can influence the
trajectory of a vehicle to which that structure is coupled (e.g.,
physically). Such switching structures, such as one or more wheels
of a vehicle or any combination of one or more wheels and/or plates
and/or other structures, can include the use of ferromagnetic or
paramagnetic materials, i.e., a material that attains magnetic
properties in the presence of a magnetic field.
[0028] The switching mechanisms discussed herein can work with any
of a number of known suspension schemes, including wheels and
magnetic levitation (maglev), and can work with any lateral
guidance scheme, including horizontal guide wheels and magnetic
guidance. Further, the vehicle can be either above or suspended
from the guideway. By having the activation mechanism on the
guideway, it is possible for the vehicle to be passive and without
the need to transmit control information to a moving vehicle. The
magnetic fields can be turned on and off in a fraction of a second
so the system is usable with very closely spaced vehicles, such as
with Personal Rapid Transit, material handling, and elevators with
multiple cabs in the same shaft. Such systems are potentially more
reliable and safe relative to systems requiring active vehicle
control.
[0029] Use of Guideway Based Magnetic Switching when the Normal
Guidance uses guide Wheels.
[0030] FIGS. 1 and 2 depict top views of one implementation of the
invention. For this embodiment, the vehicle 4 uses horizontal
wheels 5L, 5R (i.e., vertical axle wheels) as a switching structure
to provide lateral guidance by interacting with guide rails 3A, 3B,
3C, 3D. Vehicle 4 has eight guide wheels 5L, 5R. For clarity of
discussion, the suspension and propulsion mechanisms are not shown.
For normal travel away from switch points, the horizontal wheels
5L, 5R guide the vehicle 4. In the vicinity of a switch point 7,
however, there is a break in the guidance rails and the guidance is
done by a combination of electromagnets 1D, 1S and permanent
magnets 2D, 2S. Following is a more detailed discussion of
operational aspects of this embodiment.
[0031] In one operational instance, with respect to FIG. 1, the
vehicle 4 is moving from left to right and it is desired to switch
the vehicle 4 so that the vehicle 4 is diverted to the right branch
8. In order to achieve a divert, the electromagnet 1D is activated
and electromagnet 1S is not activated. The activated magnet 1D
attracts the right steel wheels 5R of the vehicle 4, located
adjacent to the activated magnet 1D, so that the vehicle 4 moves
toward the right branch 8. Shortly after the vehicle 4 starts down
the divert path 8, it encounters permanent magnets 2D, which
attract the vehicle 4 and keep it moving down the divert path 8.
The use of permanent magnets can reduce cost and complexity and can
ensure that once the vehicle has started to divert it will continue
on the path even if there is a power failure. The field from
permanent magnets 2S falls off fast enough so that it does not
produce a significant attractive force on the vehicle 4. Eventually
the vehicle 4 moves far enough down the right branch 8 so that the
left guide-wheels 5L engage the left guide rail 3D. Such
engagement, together with the right guide-wheels 5R, which
maintained contact with guide rail 3B, allows the vehicle 4 to
continue down right branch 8 with wheel guidance.
[0032] FIG. 2 depicts the same system as FIG. 1 except that in this
operational instance it is desired that the vehicle 4 continue
straight along branch 9. In order to direct straight motion,
electromagnet 1S is activated and electromagnet 1D is not
activated. The activated magnet 1S attracts the left steel wheels
5L of the vehicle 4 so that the vehicle 4 stays on the straight
path of the branch 9. Shortly after the vehicle 4 encounters the
electromagnet 1S, it will encounter permanent magnets 2S, which
continue to attract the vehicle 4 and keep it moving down the
straight path of the branch 9. The use of permanent magnets can
reduce cost and complexity and can ensure that once the vehicle has
started on the straight path it will continue on the path even if
there is a power failure. As in the previous operational instance,
the field from permanent magnets 2D falls off fast enough so that
it does not produce a significant attractive force on the vehicle
4. Eventually the vehicle 4 moves far enough so that the right
guide wheels 5R engage the right guide rail 3C. Accordingly with
the left guide-wheels 5L, which engage guide rail 3A, the vehicle 4
continues along the branch 9 with wheel guidance.
[0033] In other operational instances, if the vehicle 4 is moving
in the opposite direction, i.e., from right to left in FIGS. 1 and
2, then the vehicle 4 is merging with another branch. The
electromagnet adjacent to the appropriate side of a switching
structure of the vehicle 4 (e.g., a wheel as embodied in FIGS. 1
and 2) is activated to insure that the vehicle 4 is guided through
the region in which some of the guide wheels are not in contact
with a guide rail. If, for any reason, the electromagnets are not
activated the merging vehicle will tend to continue in a safe
manner but there may be more lateral motion than if the appropriate
electromagnet is excited.
[0034] In some embodiments, it is possible to replace the permanent
magnets with electromagnets along a length of a switch point. This
option tends to be more expensive but may be appropriate if a
vehicle operates in a region where there are substantial
ferromagnetic materials that could come in contact with the
guideway magnets, or if permanent magnets are not desired for other
reasons.
[0035] If it is not possible to use steel wheels, or other types of
wheels, to get sufficient magnetic force on the wheels, a vehicle
can use one or more ferromagnetic plates as a switching structure
on the vehicle in order to achieve attractive forces. Conducting
plates can also be used in order to achieve repulsive forces when
such an interaction is desired. A way of implementing ferromagnetic
plates is shown in FIG. 1 with ferromagnetic plates 6 located in
close proximity to, but not touching the electromagnets 1D or
permanent magnets 2D.
[0036] When magnetic switching is used with a wheel suspension
system there are at least two fairly distinct ways to provide
turning at a switch. The magnetic forces can be used to steer the
suspension wheels so that they perform the guidance, or the forces
can be used to drag the suspension wheels into the turn. For
example, when the propulsion is by a linear motor so that little to
no wheel traction is required, the wheels can have low friction
contact surfaces (e.g., be very smooth) so dragging the suspension
wheels a short distance to the side may not take too much force.
Creating a steering action on the suspension wheels may be more
complex but will require less guidance force. Both of these
approaches to steering can be achieved with the various magnetic
switching embodiments described in the present application.
[0037] When using magnetic forces to steer a vehicle, it is
sometimes desirable to have the wheels on opposite sides of the
vehicle coupled together so that a magnetic force on one side of
the vehicle can steer both wheels. Such coupling can also be
implemented with respect to use of other types, and combinations
of, switching structures (e.g., steering can be achieved by
coordinated movement of switching structures, such as plates, to
direct a vehicle).
[0038] Magnet Design
[0039] FIGS. 3A and 3B show top and cross section views,
respectively, of possible ways to use a U-shape electromagnet to
create an attractive force on a guide wheel in accord with an
embodiment of the invention. Guide wheel 14 has a thin rim of
resilient material to reduce noise and wear on the guideway, and
includes a ferromagnetic core so that the electromagnets can create
an attractive force on the wheel. The wheel 14 contacts a running
surface 13 made of stainless steel or other non ferromagnetic
material with relatively high resistivity. The electromagnet 1S, 1D
has a core 10, legs 12, and windings 11 forming a coil on the legs
12 that are excited with current so as to create a strong magnetic
field in the vicinity of the wheel 14 where it rolls on the running
surface 13.
[0040] The dimensions of the guideway and magnets can vary over a
wide range depending on the size of the vehicles. For example, it
can be desirable to choose guideway and magnet configurations to
use as small a gap as possible in the magnetic structure, and/or to
get enough force to ensure the vehicle will move in the desired
direction.
[0041] Many variations are possible, including eliminating the
resilient tread on the wheel and/or eliminating the running surface
so that the wheels contact the legs of the electromagnet. These
changes would increase the force, though greater noise and wear on
the guideway magnets may result.
[0042] FIGS. 4A and 4B depict another embodiment of a system
similar to that shown in FIGS. 3A and 3B except that the attractive
force is applied to ferromagnetic plate 16, acting as the switching
structure, instead of to the wheels. A cover 17 may be used to
protect the coils and laminations, though such cover is not
required.
[0043] Alternatively, if the ferromagnetic plate 16 in FIGS. 4A and
4B is replaced by a non-ferromagnetic but conducting plate, and the
coil formed by the windings 11 is excited with a suitable AC
frequency, then a repulsive force acts on the plate. This can be
used to push the vehicle in a desired direction. In some cases it
is possible to repel a ferromagnetic plate by using a high enough
electrical frequency. The AC frequency is typically in the range of
50 to 500 Hz for repelling a non ferromagnetic plate, and higher
for repelling a ferromagnetic plate.
[0044] FIGS. 5A and 5B show how permanent magnets can create a
force as used in embodiments of the invention. The use of permanent
magnets is effective once the vehicle has started moving in the
desired direction at a switch point but is in a region where there
is a break in the normal guidance mechanism. FIG. 5A shows a
cross-sectional view of the use of 3 permanent magnets 21, 22, 23
with different field orientations as indicated by the arrows 41,
42, 43. FIG. 5B shows magnets 21 and 23 of FIG. 5A replaced by
wedge-shaped steel poles 25, 26 that convey the magnetic flux to
the air gap. In both cases there is a strong attractive force as
indicated schematically by the field arrows 20 in the air gap. The
use of 3 magnets will give a stronger force, though the cost may be
somewhat higher. Either of these, or still other, configurations of
permanent magnets can be used to hold the vehicle to the correct
side of the guideway when other guidance forces are unavailable.
The magnets can be almost any length in the direction perpendicular
to the cross-sectional plane, and the surface of a magnet can be
chosen to follow the contours of the guide rail.
[0045] In some cases, it may be desirable to use permanent magnets
in conjunction with electromagnets to create a controllable
attractive force. Consistent with embodiments of the invention,
FIGS. 6A and 6B show magnetic field lines for a U-shaped magnet
similar to the ones in FIGS. 3A, 3B, 4A, and 4B except that the
electromagnet legs 34 have permanent magnets 32 attached to them.
Coils 33 are wound around both the magnets 32 and the legs 34. In
order to attract the vehicle ferromagnetic structure 31, the
winding 33 is excited so as to aid the field of the permanent
magnet, as shown in FIG. 6A. In order to not attract the vehicle,
the current is reversed so that it cancels most of the field, as
shown in FIG. 6B. In some cases, this design can produce
significantly more force for a given coil dissipation, particularly
if the magnetic gap is large.
[0046] Still other magnet configurations can be used as will be
apparent to those skilled in the art.
[0047] Elevators
[0048] The switching scheme described in the present application
can be used for motion up inclines or for vertical motion in an
elevator shaft. For example, vehicles can be propelled via linear
motors up one shaft and down another, the shafts serving as
guideways. Magnetic switching within the shaft can then used to
move the vehicles (i.e., cabs) from one shaft to the other.
[0049] Such a system can resemble the system of FIGS. 1-2 modified
such that the straight guideway 9 is vertical, and the branching
guideway 8 is horizontal to the ground. The electromagnets 1S, 1D
and/or permanent magnets 2S, 2D can provide appropriate lateral
force to move the vehicle 4 from one elevator shaft (i.e., the
guideway 9) laterally on the branching guideway 8 to another
elevator shaft (another straight guideway). Furthermore, the
branching guideway 8 can be oriented such that the vehicle 4 always
remain upright. For example, the straight guideway 9 can be
perpendicular to the branching guideway 8, such that when the
vehicle 4 reaches the intersection of guideways 8, 9, electromagnet
1S can be activated to push the vehicle 4 laterally into the
branching guideway 8. Alternatively, electromagnet 1D can be
activated to pull the vehicle 4 into the branching guideway 8, or
possibly both electromagnets 1S, 1D can work in complementary
fashion.
[0050] An advantage of using magnetic switching as disclosed herein
for elevators from one shaft to another is the ability to work
reliably with short headway. For a tall building, embodiments of
the invention can allow the use of at least 4 cabs per shaft and
operation with headways of only 10 to 15 seconds. This allows a
factor of 4 or more reduction in the number of shafts required to
achieve a given capacity and the reduced elevator area creates
significantly more usable space on all floors.
[0051] Variations
[0052] There are many possible variations on aspects the invention
beyond those described herein. The following are a few non-limiting
examples.
[0053] It is understood that the illustrative embodiment depicted
in FIGS. 1 and 2 and the operational modes described with respect
to such an illustrative embodiment are all merely exemplary. Many
variations of the components, and the workings of such components,
can be implemented within the scope of the present application. For
example the number of wheels that act as a switching structure
(e.g., one or more); the number, size, and strength of any magnets
positioned with respect to a guideway; the orientation of the
wheels with respect to the guideway (e.g., wheels need not be
horizontally-oriented, but can be vertically-oriented or any other
angle); the types of vehicle suspensions (e.g., wheeled, magnetic,
air-cushioned, etc.); the configuration of the guideway (e.g.,
having a portion extending laterally toward a vehicle moving
thereon to orient a magnet adjacent to a switching structure of the
vehicle, such as a U-shaped guideway); the number of branches in a
switching point (e.g., 3 or more branches); and the number of
vehicles in a train that utilize any embodiments of the invention
described herein, can all be varied. These variations, among others
described herein and those understood by skilled artisans, are all
within the scope of the present application.
[0054] It is possible to use other methods than guide wheels for
normal guidance. For example, if the normal vehicle guidance is
magnetic, such as described in U.S. Pat. No. 6,101,952 (which is
hereby incorporated by reference herein in its entirety), then the
magnetic switching forces may be so large as to cause the vehicle
plate to touch the magnet. In this case, it is desirable to use gap
sensors and feedback to control the force so contact does not
occur.
[0055] The vehicle may be supported by two or more bogies, as with
typical railroad cars. In this case each bogie can have either
ferromagnetic wheels or plates or other switching structure(s) so
that the magnetic switching forces can direct the bogies in the
desired direction.
[0056] FIG. 1 shows a vehicle with 8 guide wheels. It is definitely
possible to operate with only 4 guide wheels and, in some cases,
only 2 may be sufficient.
[0057] In many cases a vehicle will be supported by wheels, but it
also possible to switch a vehicle that is supported by other
mechanisms such as magnetic forces. In the case of systems
utilizing ElectroDynamic Suspension (EDS) with repulsive forces
acting on a conducting sheet or other conducting structure, the
magnetic switching forces can control the lateral position of the
vehicle through a switch area. In the case of systems utilizing
ElectroMagnetic Suspension (EMS) with the vehicle suspended below
the guideway, the magnetic switching can be used to move the
vehicles laterally at a switch.
[0058] A further appreciation of the foregoing can be attained by
reference to U.S. Pat. No. 6,101,952, which discusses the use of
magnetic forces for both guidance and switching. That material is
hereby incorporated by reference herein in its entirety.
[0059] Although specific embodiments of the invention have been
shown and described, it will be understood that other embodiments
and modifications which will occur to those of ordinary skill in
the art fall within the true spirit and scope of the invention as
set forth in the appended claims. Indeed, one or more features
illustrated or described in connection with one embodiment may be
combined with one or more features of other embodiments. Such
modifications and variations are intended to be included within the
scope of the present invention.
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