WO1999019973A1 - Electromagnetic apparatus for producing linear motion - Google Patents

Electromagnetic apparatus for producing linear motion Download PDF

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Publication number
WO1999019973A1
WO1999019973A1 PCT/GB1998/003092 GB9803092W WO9919973A1 WO 1999019973 A1 WO1999019973 A1 WO 1999019973A1 GB 9803092 W GB9803092 W GB 9803092W WO 9919973 A1 WO9919973 A1 WO 9919973A1
Authority
WO
WIPO (PCT)
Prior art keywords
armature
stator
piston
electromagnetic apparatus
coils
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB1998/003092
Other languages
French (fr)
Other versions
WO1999019973A9 (en
Inventor
Phillip Raymond Michael Denne
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Advanced Motion Technologies LLC
Linear Motion Technology Inc
Original Assignee
Advanced Motion Technologies LLC
Linear Motion Technology Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to AU94515/98A priority Critical patent/AU9451598A/en
Application filed by Advanced Motion Technologies LLC, Linear Motion Technology Inc filed Critical Advanced Motion Technologies LLC
Priority to JP2000516427A priority patent/JP2001520499A/en
Priority to US09/529,692 priority patent/US6462439B1/en
Priority to AT98947676T priority patent/ATE300117T1/en
Priority to CA002306466A priority patent/CA2306466C/en
Priority to EP98947676A priority patent/EP1023764B1/en
Priority to KR1020007004046A priority patent/KR20010031143A/en
Priority to DE69830916T priority patent/DE69830916T2/en
Priority to IL13565198A priority patent/IL135651A0/en
Publication of WO1999019973A1 publication Critical patent/WO1999019973A1/en
Anticipated expiration legal-status Critical
Publication of WO1999019973A9 publication Critical patent/WO1999019973A9/en
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
    • H02K41/02—Linear motors; Sectional motors
    • H02K41/03—Synchronous motors; Motors moving step by step; Reluctance motors
    • H02K41/031—Synchronous motors; Motors moving step by step; Reluctance motors of the permanent magnet type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
    • H02K41/02—Linear motors; Sectional motors

Definitions

  • the present invention relates to electromagnetic apparatus for producing linear motion.
  • Various linear motor configurations are described in 093/ 01646.
  • the devices to which this prior art relates have axial symmetry and are formed as piston-in-cylinder machines.
  • the principal advantage of axial symmetry lies in the fact that the strong attractive forces between the magnetic elements of the stator and the magnetic elements of the armature are balanced about a central axis, so that the bearings of the machine do not need to withstand attractive forces.
  • a further advantage of the axially-symmetric construction is that the magnetic fields of the machine, whether generated as a result of electrical currents in conductors or produced by permanent magnets, can be contained within an outer steel case of the actuator. However they are generated, the magnetic fields can intersect the electrical coils of the machine with a high degree of efficiency.
  • Yet another advantage of the axially-symmetric construction is that, by utilising a cylindrical stator it is possible to form a sliding seal between the stator and the armature, which then allows of the possibility of creating a gas spring between the stator and armature by closing one end of the stator. Such an arrangement is described in more detail in the Applicant's international application PCT/GB98/02823.
  • a controlled vibration can be applied: this may be used for example in association with earth-moving machinery.
  • the motion of the an unrestricted piston might be used to vary the total enclosed volume and/or pressure of a fluid system to which the piston chamber is connected.
  • Such a machine might be used as a fluid pump, to dispense metered fluid, to vary the pressure in a sensory pad or to form part of a sensitive and precise fluid pressure suspension system.
  • the present invention seeks to provide a linear actuator comprising a stator and an armature in which the armature is not attached to an output member which protrudes from the stator, such as the actuator arm or piston rod of known such actuators. That is to say, the armature of this invention is a piston that is free (or substantially free) to move within the stator volume.
  • the term "free piston” will be understood to mean a member movable within a working volume without having a force-transmitting member such as a piston rod.
  • the present invention provides electromagnetic apparatus for producing an axially directed force comprising a stator having a plurality of axially spaced coils around a working volume within which an armature in the form of a free piston is axially displaceable, the armature having means for producing a magnetic field a substantially radially directed part of which intersects at least some of the coils of the stator such that a resultant axially directed force is generated when a current flows in the coils.
  • the physical parameters of the device are so chosen that the electrical coils may be connected to an electronic drive unit for controlling the phase, frequency or amplitude of the current in the coils so as to cause the desired axially-directed electromagnetic force to be created between the armature and the stator.
  • the armature and the stator are of circular cross section. This makes it easy for the outer surface of the armature to be sealed with respect to the internal surface of the stator, so as to prevent or at least restrict fluid flow between the volumes on either side of the piston.
  • Means may be provided for sensing the position of the piston so as to optimise the configuration of the currents supplied to the coils by the electronic drive unit.
  • the electronic drive unit may also be arranged to produce a signal representative of the current supplied to the actuator, the integral of such signal being used to control the pressure of a gas supply to at least to one side of a sealed armature.
  • Figure 1 is a schematic axial sectional view of a free piston actuator formed as a first embodiment of the present invention
  • Figure 2 is an axial sectional view of an alternative embodiment having induction drive and a working tool
  • Figure 3 is a schematic axial sectional view of an alternative embodiment utilised in a pressure pad drive system
  • Figure 4 is an axial sectional view of a further alternative embodiment employing ring magnets.
  • Figure 1 shows a particular form of the device in which the armature (piston) is required to be sealed to the inner surface of the armature tube.
  • the stator 1 carries an assembly of coils 2 extending circumferentially around the axis of the cylinder.
  • the piston 3, moving on bearings 9 and seals 6, carries an arrangement of magnets 4 and polepieces 5 to produce a magnetic field alternating in polarity along the axis of the cylinder.
  • the ends of the device include closures 7, in which, in this embodiment, there are provided fluid passages 8 so as to allow fluid to be moved by the action of the piston 3, if that motion is significant in relation to the enclosed volume.
  • Figure 2 shows an example of a free-piston actuator used to deliver repeated blows to a tool 10.
  • the armature of this device consists of a hardened core 11 which may also contain lead to increase its mass.
  • the core is keyed to an outer magnetic steel cylinder 12 which carries a series of slots in which are copper rings 13.
  • the coil assembly 2 is energised to produce an alternating magnetic field that travels along the axis of the piston. This induces currents in the armature rings 13 so as to produce a second alternating magnetic field, whose interaction with the first field accelerates the piston. It is necessary for the piston to be fitted with simple bearing rings (not shown, but similar to those of 9 in Figure 1) . Nevertheless, it should be noted that the inductive forces that accelerate the piston also act to hold it away from the sides of the cylinder when in motion; such bearings do not therefore need to be of high quality.
  • Arrangements are made to allow air or other gas within the cylinder 12 to pass freely between the opposing ends of the device shown in Figure 2, so as not to impede the motion of the piston.
  • the electromagnetic configuration of the invention is not restricted to the use of permanent magnets and an ironless stator assembly, as shown by way of example in Figure 1, or to the use of an induction technique as shown by way of example in Figure 2.
  • the armature or piston may, with advantage in certain conditions, use a variable-reluctance drive technique and/or the stator may have slots housing the coils.
  • Figure 3 shows a particular form of the actuator in relation to a pressure pad 15 carrying a load 19.
  • the principal parts of the actuator device are similar to those described in Figure 1.
  • piston is shown as being provided with bearings 9 but to be sealed to the pressure pad 15 and to the source of pressurising fluid by bellows 18.
  • Figure 4 shows a modified form of the device illustrated in Figure 3 , in that the axially-alternate magnetic field of the piston is produced by plane rings of magnetic material instead of discs. This technique allows the device to be of lightweight construction whilst applying force to a diaphragm 20 having an area larger than that of the magnets.
  • Position-sensing means (not shown) are also utilised by the control system to ensure that the median position of the piston is in the central region of the actuator.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Reciprocating, Oscillating Or Vibrating Motors (AREA)
  • Linear Motors (AREA)
  • Vehicle Body Suspensions (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
  • Valve Device For Special Equipments (AREA)

Abstract

Electromagnetic apparatus for producing an axially directed force comprising a stator (1) having a plurality of axially spaced coils (2) around a working volume within which an armature in the form of a free piston (3) is axially displaceable, the armature having means for producing a magnetic field a substantially radially directed part of which intersects at least some of the coils of the stator such that a resultant axially directed force is generated when a current flows in the coils.

Description

ELECTROMAGNETIC APPARATUS FOR PRODUCING LINEAR MOTION
The present invention relates to electromagnetic apparatus for producing linear motion. A number of designs of linear electromagnetic actuator, sometimes termed a linear motor, have been produced. Various linear motor configurations are described in 093/ 01646. The devices to which this prior art relates have axial symmetry and are formed as piston-in-cylinder machines. The principal advantage of axial symmetry lies in the fact that the strong attractive forces between the magnetic elements of the stator and the magnetic elements of the armature are balanced about a central axis, so that the bearings of the machine do not need to withstand attractive forces.
A further advantage of the axially-symmetric construction is that the magnetic fields of the machine, whether generated as a result of electrical currents in conductors or produced by permanent magnets, can be contained within an outer steel case of the actuator. However they are generated, the magnetic fields can intersect the electrical coils of the machine with a high degree of efficiency.
Yet another advantage of the axially-symmetric construction is that, by utilising a cylindrical stator it is possible to form a sliding seal between the stator and the armature, which then allows of the possibility of creating a gas spring between the stator and armature by closing one end of the stator. Such an arrangement is described in more detail in the Applicant's international application PCT/GB98/02823.
All these known linear actuators are constructed and designed to apply a force between machine components connected or mechanically linked to the stator and armature, for which purpose these have a configuration which permits such connection. However, there are certain mechanical systems in which it is not required to connect a moving element physically to a drive element. In such circumstances the armature of the actuator does not have to have a continuous direct connection to the external environment. For example, it may be required for an element to be repeatedly driven to reciprocate along a guide member so as to deliver energy at the ends of its stroke when it changes direction. A road breaker or so-called "pneumatic hammer" works in this way by the alternate application of opposite forces by directing pressure fluid alternately into opposite chambers of a pneumatic cylinder with a flutter valve.
If the moving element has significant inertia, against which the external "stator" of the machine is designed to experience a reaction, a controlled vibration can be applied: this may be used for example in association with earth-moving machinery. As a third example, the motion of the an unrestricted piston might be used to vary the total enclosed volume and/or pressure of a fluid system to which the piston chamber is connected. Such a machine might be used as a fluid pump, to dispense metered fluid, to vary the pressure in a sensory pad or to form part of a sensitive and precise fluid pressure suspension system.
The present invention seeks to provide a linear actuator comprising a stator and an armature in which the armature is not attached to an output member which protrudes from the stator, such as the actuator arm or piston rod of known such actuators. That is to say, the armature of this invention is a piston that is free (or substantially free) to move within the stator volume. As used in this specification the term "free piston" will be understood to mean a member movable within a working volume without having a force-transmitting member such as a piston rod.
According to one aspect of the present invention, therefore, the present invention provides electromagnetic apparatus for producing an axially directed force comprising a stator having a plurality of axially spaced coils around a working volume within which an armature in the form of a free piston is axially displaceable, the armature having means for producing a magnetic field a substantially radially directed part of which intersects at least some of the coils of the stator such that a resultant axially directed force is generated when a current flows in the coils.
Preferably the physical parameters of the device are so chosen that the electrical coils may be connected to an electronic drive unit for controlling the phase, frequency or amplitude of the current in the coils so as to cause the desired axially-directed electromagnetic force to be created between the armature and the stator.
In one embodiment the armature and the stator are of circular cross section. This makes it easy for the outer surface of the armature to be sealed with respect to the internal surface of the stator, so as to prevent or at least restrict fluid flow between the volumes on either side of the piston.
Means may be provided for sensing the position of the piston so as to optimise the configuration of the currents supplied to the coils by the electronic drive unit.
The electronic drive unit may also be arranged to produce a signal representative of the current supplied to the actuator, the integral of such signal being used to control the pressure of a gas supply to at least to one side of a sealed armature. Various embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a schematic axial sectional view of a free piston actuator formed as a first embodiment of the present invention;
Figure 2 is an axial sectional view of an alternative embodiment having induction drive and a working tool; Figure 3 is a schematic axial sectional view of an alternative embodiment utilised in a pressure pad drive system; and
Figure 4 is an axial sectional view of a further alternative embodiment employing ring magnets.
Figure 1 shows a particular form of the device in which the armature (piston) is required to be sealed to the inner surface of the armature tube. In this example the stator 1 carries an assembly of coils 2 extending circumferentially around the axis of the cylinder. The piston 3, moving on bearings 9 and seals 6, carries an arrangement of magnets 4 and polepieces 5 to produce a magnetic field alternating in polarity along the axis of the cylinder. The ends of the device include closures 7, in which, in this embodiment, there are provided fluid passages 8 so as to allow fluid to be moved by the action of the piston 3, if that motion is significant in relation to the enclosed volume. Figure 2 shows an example of a free-piston actuator used to deliver repeated blows to a tool 10. The armature of this device consists of a hardened core 11 which may also contain lead to increase its mass. The core is keyed to an outer magnetic steel cylinder 12 which carries a series of slots in which are copper rings 13.
The coil assembly 2 is energised to produce an alternating magnetic field that travels along the axis of the piston. This induces currents in the armature rings 13 so as to produce a second alternating magnetic field, whose interaction with the first field accelerates the piston. It is necessary for the piston to be fitted with simple bearing rings (not shown, but similar to those of 9 in Figure 1) . Nevertheless, it should be noted that the inductive forces that accelerate the piston also act to hold it away from the sides of the cylinder when in motion; such bearings do not therefore need to be of high quality.
Arrangements (not shown) are made to allow air or other gas within the cylinder 12 to pass freely between the opposing ends of the device shown in Figure 2, so as not to impede the motion of the piston.
It will be understood that the electromagnetic configuration of the invention is not restricted to the use of permanent magnets and an ironless stator assembly, as shown by way of example in Figure 1, or to the use of an induction technique as shown by way of example in Figure 2. The armature or piston may, with advantage in certain conditions, use a variable-reluctance drive technique and/or the stator may have slots housing the coils.
Figure 3 shows a particular form of the actuator in relation to a pressure pad 15 carrying a load 19. The principal parts of the actuator device are similar to those described in Figure 1.
In this example the piston is shown as being provided with bearings 9 but to be sealed to the pressure pad 15 and to the source of pressurising fluid by bellows 18.
Figure 4 shows a modified form of the device illustrated in Figure 3 , in that the axially-alternate magnetic field of the piston is produced by plane rings of magnetic material instead of discs. This technique allows the device to be of lightweight construction whilst applying force to a diaphragm 20 having an area larger than that of the magnets.
As described in the Applicant's International Patent Application PCT/GB98/02823 the time integral of the current consumed by the device is continuously computed and the fluid pressure in the volume 17 beneath the piston is frequently adjusted to bring this integral to zero. This control technique ensures that the mean values of the pressures above and below the piston are equalised.
Position-sensing means (not shown) are also utilised by the control system to ensure that the median position of the piston is in the central region of the actuator.
It will be understood that the use of a bellows to replace the piston seal removes the constraint that the piston and the internal surface of the armature should be of circular cross-section.
It will be further understood that the principles of this invention are not compromised by the use of springs or equivalent compliances to provide a mechanical bias to the position of the piston in the absence of electrical power and that such compliant biasing devices may utilise permanent magnetic fields. In embodiments in which the armature is intended, in use, to reciprocate at high frequency the air trapped in the stator cylinder on either side of the pistons may act as a gas spring to cushion the impact at each end of its stroke. The piston/cylinder seal does not have to be very airtight in that the periodic motion may have a sufficiently high frequency for leakage effect to be minimal.

Claims

1. Electromagnetic apparatus for producing an axially directed force comprising a stator having a plurality of axially spaced coils around a working volume within which an armature in the form of a free piston is axially displaceable, the armature having means for producing a magnetic field a substantially radially directed part of which intersects at least some of the coils of the stator such that a resultant axially directed force is generated when a current flows in the coils.
2. Electromagnetic apparatus according to Claim 1, in which the stator has openings to allow the ingress and egress of fluid from the working volume of the stator upon displacement of the armature within it.
3. Electromagnetic apparatus according to Claim 1, in which the armature has openings to allow the transfer of fluid from one side thereof to the other upon displacement of the armature within the working volume of the stator.
4. Electromagnetic apparatus according to any of Claims 1 to 3 , in which there are provided means for resiliently resisting the motion of the armature at or adjacent at least one end of the range of movement thereof within the stator.
5. Electromagnetic apparatus according to Claim 4, in
PCT/GB1998/003092 1997-10-15 1998-10-15 Electromagnetic apparatus for producing linear motion Ceased WO1999019973A1 (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
DE69830916T DE69830916T2 (en) 1997-10-15 1998-10-15 ELECTROMAGNETIC DEVICE FOR GENERATING A LINEAR MOTION
JP2000516427A JP2001520499A (en) 1997-10-15 1998-10-15 Electromagnetic device that generates linear motion
US09/529,692 US6462439B1 (en) 1997-10-15 1998-10-15 Electromagnetic apparatus for producing linear motion
AT98947676T ATE300117T1 (en) 1997-10-15 1998-10-15 ELECTROMAGNETIC DEVICE FOR GENERATING LINEAR MOTION
CA002306466A CA2306466C (en) 1997-10-15 1998-10-15 Electromagnetic apparatus for producing linear motion
AU94515/98A AU9451598A (en) 1997-10-15 1998-10-15 Electromagnetic apparatus for producing linear motion
KR1020007004046A KR20010031143A (en) 1997-10-15 1998-10-15 Electromagnetic apparatus for producing linear motion
EP98947676A EP1023764B1 (en) 1997-10-15 1998-10-15 Electromagnetic apparatus for producing linear motion
IL13565198A IL135651A0 (en) 1997-10-15 1998-10-15 Electromagnetic apparatus for producing linear motion

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9721747.5A GB9721747D0 (en) 1997-10-15 1997-10-15 Electromagnetic apparatus for producing linear motion
GB9721747.5 1997-10-15

Publications (2)

Publication Number Publication Date
WO1999019973A1 true WO1999019973A1 (en) 1999-04-22
WO1999019973A9 WO1999019973A9 (en) 2000-07-20

Family

ID=10820525

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1998/003092 Ceased WO1999019973A1 (en) 1997-10-15 1998-10-15 Electromagnetic apparatus for producing linear motion

Country Status (13)

Country Link
US (1) US6462439B1 (en)
EP (1) EP1023764B1 (en)
JP (1) JP2001520499A (en)
KR (1) KR20010031143A (en)
CN (1) CN1278963A (en)
AT (1) ATE300117T1 (en)
AU (1) AU9451598A (en)
CA (1) CA2306466C (en)
DE (1) DE69830916T2 (en)
GB (1) GB9721747D0 (en)
IL (1) IL135651A0 (en)
RU (1) RU2000109578A (en)
WO (1) WO1999019973A1 (en)

Cited By (3)

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GB2345440A (en) * 1998-11-21 2000-07-12 Advanced Motion Tech Llc Load support with adjustable pressure support surface.
KR100451301B1 (en) * 2001-03-10 2004-10-06 이찬재 Reciprocating electrical generator
WO2018142137A1 (en) * 2017-02-06 2018-08-09 Libertine Fpe Limited Linear electrical machine

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GB0016059D0 (en) * 2000-06-30 2000-08-23 Denne Phillip R M Improvements in motion simulators
US6742960B2 (en) 2002-07-09 2004-06-01 Caterpillar Inc. Vibratory compactor and method of using same
US6914351B2 (en) 2003-07-02 2005-07-05 Tiax Llc Linear electrical machine for electric power generation or motive drive
NZ528332A (en) * 2003-09-22 2006-04-28 Ramet Holdings Ltd Impact driver for driving poles, piles or posts including linear induction motor
US7009310B2 (en) * 2004-01-12 2006-03-07 Rockwell Scientific Licensing, Llc Autonomous power source
WO2007061920A2 (en) * 2005-11-17 2007-05-31 Tiax Llc Linear electrical machine for electric power generation or motive drive
GB2456795B (en) * 2008-01-24 2010-03-31 Siemens Magnet Technology Ltd A limiter for limiting the motion of components in a cryostat
US9685847B2 (en) 2014-01-31 2017-06-20 Haier Us Appliance Solutions, Inc. Linear motor with electromagnetically actuated spring mover
EP3215261B1 (en) 2014-11-07 2021-12-15 Genesis Technologies, LLC Linear reciprocating actuator
US9746211B2 (en) 2015-08-26 2017-08-29 Emerald Energy NW, LLC Refrigeration system including micro compressor-expander thermal units
US10837802B2 (en) * 2016-07-22 2020-11-17 Regents Of The University Of Minnesota Position sensing system with an electromagnet
US10914566B2 (en) * 2016-07-22 2021-02-09 Regents Of The University Of Minnesota Position sensing system with an electromagnet
CN109789977B (en) 2016-10-05 2021-07-23 莱特拉姆有限责任公司 Linear Motor Conveyor System
DE102017102835A1 (en) 2017-02-13 2018-08-16 Benteler Maschinenbau Gmbh Electromagnetic impact drive
EP3939708B1 (en) * 2019-03-12 2023-11-08 Alps Alpine Co., Ltd. Electromagnetic drive device and operation device
CN112922990B (en) * 2021-01-19 2022-09-09 上海隐冠半导体技术有限公司 A magnetic spring device

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GB645281A (en) * 1947-12-18 1950-10-25 Malcolm Christie Brittain Solenoid devices
GB2017420A (en) * 1977-07-28 1979-10-03 Drum Eng Co Ltd Electrically driven pumps
US4541787A (en) * 1982-02-22 1985-09-17 Energy 76, Inc. Electromagnetic reciprocating pump and motor means
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Cited By (7)

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Publication number Priority date Publication date Assignee Title
GB2345440A (en) * 1998-11-21 2000-07-12 Advanced Motion Tech Llc Load support with adjustable pressure support surface.
KR100451301B1 (en) * 2001-03-10 2004-10-06 이찬재 Reciprocating electrical generator
WO2018142137A1 (en) * 2017-02-06 2018-08-09 Libertine Fpe Limited Linear electrical machine
CN110337582A (en) * 2017-02-06 2019-10-15 自由活塞式发动机有限公司 Linear motor
CN110337582B (en) * 2017-02-06 2021-10-29 自由活塞式发动机有限公司 Linear motor
EP4236044A3 (en) * 2017-02-06 2023-09-06 Libertine FPE Ltd Linear electrical machine
US11799360B2 (en) 2017-02-06 2023-10-24 Libertine Fpe Ltd Linear electrical machine

Also Published As

Publication number Publication date
IL135651A0 (en) 2001-05-20
EP1023764B1 (en) 2005-07-20
WO1999019973A9 (en) 2000-07-20
US6462439B1 (en) 2002-10-08
KR20010031143A (en) 2001-04-16
EP1023764A1 (en) 2000-08-02
CA2306466C (en) 2010-01-05
JP2001520499A (en) 2001-10-30
DE69830916T2 (en) 2006-05-24
CN1278963A (en) 2001-01-03
GB9721747D0 (en) 1997-12-10
RU2000109578A (en) 2002-07-20
CA2306466A1 (en) 1999-04-22
ATE300117T1 (en) 2005-08-15
AU9451598A (en) 1999-05-03
DE69830916D1 (en) 2005-08-25

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