Tray conveyor driven by brushless DC motor

Patent metadata

Field	Value
Publication number	US-10994953-B2
Application number	US-201816609694-A
Country	US
Kind code	B2
Filing date	Apr 3, 2018
Priority date	May 2, 2017
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A conveyor for conveying articles supported on independently powered and controllable trays. Each tray comprises a blade suspended from an article-supporting platform. A series of drive coils is embedded in the blade. A battery and a controller embedded in the tray drive the drive coils. The blade rides in a slot between two conveyor rails that support the tray platform. The slot is bounded by an array of permanent magnets along each rail. The drive coils produce an electromagnetic field that interacts with the permanent-magnet field in the slot to form a brushless dc motor that propels the tray along the rails.

First claim

What is claimed is:

1. A conveyor comprising:
a rail having an array of permanent magnets embedded in and extending along the length of the rail to form a permanent-magnet stator creating a magnetic field;
a tray supported on the rail and having a top article-supporting surface and having a series of commutated drive coils housed in the tray as a forcer coacting with the permanent-magnet stator to form a brushless linear dc motor;
wherein the tray further includes a tray controller housed in the tray driving the drive coils to produce a traveling electromagnetic wave that interacts with the magnetic field to propel the tray along the rail.

2. A conveyor as in claim 1 comprising:
a tray conveyor segment extending from a first end to a second end in a conveying direction and including:
a pair of the rails closely spaced and separated by a slot and having tops, each of the rails including such an array of permanent magnets creating a magnetic field across the slot;
wherein the tray includes:
a platform forming the top article-supporting surface and a bottom surface supported on the tops of the rails;
a blade extending downward from the bottom surface and in the conveying direction to ride in the slot and housing the series of commutated drive coils;
wherein the tray controller drives the drive coils to produce the traveling electromagnetic wave that interacts with the magnetic field to propel the tray in the conveying direction.

3. A conveyor as in claim 2 wherein the drive coils are three-phase coils, the tray controller commutates current through the three-phase coils to form the brushless linear dc motor with the permanent-magnet arrays in the rails.

4. A conveyor as in claim 3 wherein the tray includes sensors in the blade sensing the magnitude of the magnetic field and sending sensor signals to the tray controller to commutate the current.

5. A conveyor as in claim 1 wherein the drive coils have ironless cores.

6. A conveyor as in claim 1 wherein the tray includes a battery to power the tray controller and the series of drive coils.

7. A conveyor as in claim 1 further comprising a primary conductor loop external to the tray and extending in the conveying direction along a length of the rail and wherein the tray further includes a secondary coil inductively coupled to the primary conductor loop to supply power to the tray while on the rail.

8. A conveyor as in claim 7 wherein the tray includes a battery to power the tray controller and the series of drive coils and wherein the battery is recharged through the secondary coil.

9. A conveyor as in claim 7 wherein the tray includes a battery and a switch to connect between powering the tray controller through the secondary coil or powering the tray controller from the battery upon a loss of power from the secondary coil.

10. A conveyor as in claim 7 further comprising primary capacitors connected to the primary conductor loop at spaced apart positions along its length and wherein the tray includes a secondary capacitor connected to the secondary coil and wherein the primary conductor loop and the secondary coil are tuned for resonant delivery of power to the tray.

11. A conveyor as in claim 2 further comprising first and second primary conductor loops external to the tray and extending in the conveying direction along the length of the rails on the opposite side and wherein the tray further includes first and second secondary coils inductively coupled to the first and second primary conductor loops, respectively.

12. A conveyor as in claim 11 wherein the rails have laterally outward extensions in which the primary conductor loop and the second primary conductor loop are embedded and which support the platform under the secondary coil and the second secondary coil.

13. A conveyor as in claim 7 comprising a pair of the rails closely spaced and separated by a slot and wherein the primary conductor loop includes a first conductor segment in one of the rails connected to a second conductor segment in the other of the rails and wherein the secondary coil is centrally located in the tray.

14. A conveyor as in claim 2 wherein the slot widens at the tops of the rails.

15. A conveyor as in claim 2 wherein the tops of the rails are convexly curved.

16. A conveyor as in claim 2 further comprising a rail base joining the rails and forming a closed end of the slot and a series of single legs extending downward from the base to mount the conveyor to a floor.

17. A conveyor as in claim 1 wherein the tray further includes an antenna for wireless communication with the tray controller.

18. A conveyor as in claim 2 further comprising:
a carriage conveyor segment like the tray conveyor segment but arranged with carriage rails and a carriage slot perpendicular to and skewed below the rails and slot of the tray conveyor segment;
a carriage including:
a carriage platform supported on the tops of the carriage rails;
a carriage blade extending downward from the carriage platform to ride in the carriage slot;
a series of carriage drive coils in the carriage blade;
a pair of closely spaced transfer rails separated by a transfer slot and extending up from the carriage platform to tops level with the tops of the rails in the tray conveyor segment to receive a tray from or discharge a tray to the tray conveyor segment;
a carriage controller driving the carriage drive coils to produce a traveling electromagnetic wave that interacts with the magnetic field in the carriage slot to propel the carriage along the carriage conveyor segment in a transverse direction from a first position in which the transfer rails are aligned with the rails of the tray conveyor segment to a second position in which the transfer rails are transversely offset from the rails of the tray conveyor segment.

19. A conveyor as in claim 18 comprising a plurality of the tray conveyor segments arranged in parallel on the same side or on opposite sides of the carriage conveyor segment so that the carriage can receive the tray from one of the tray conveyor segments and discharge the tray to another of the tray conveyor segments.

20. A conveyor as in claim 2 further comprising:
a plurality of the tray conveyor segments in which a first one of the tray conveyor segments extends obliquely from the first end of a second one of the tray conveyor segments across a gap;
a diverter carriage segment having a cylindrical diverter base housing a ring of permanent magnets creating a magnetic field about the periphery of the diverter base;
a diverter carriage including:
a diverter carriage platform supported on the diverter base and having side skirts extending downward around the periphery of the diverter base;
a series of diverter carriage drive coils in each of the side skirts;
a pair of closely spaced diverter rails separated by a diverter slot and extending up from the diverter carriage platform to tops level with the tops of the rails in the first and second tray conveyor segments to receive a tray from or discharge a tray to the tray conveyor segment;
a diverter carriage controller driving the diverter carriage drive coils to produce a traveling electromagnetic wave that interacts with the magnetic field around the diverter base to rotate the diverter from a first position in which the diverter rails are aligned with the rails of the first one of the tray conveyor segments to a second position in which the diverter rails are aligned with the rails of the second one of the tray conveyor segments.

Assignees

• Laitram Llc

Inventors

• Ragan Bryant G

Classifications

• H04N23/687

  by shifting the lens or sensor position · CPC title

• H02K3/47

  Air-gap windings, i.e. iron-free windings · CPC title

• B60L13/03 Primary

  Electric propulsion by linear motors · CPC title

• B65G47/642

  in a horizontal plane · CPC title

• H02K41/031

  of the permanent magnet type · CPC title