Decentralized drive system for a conveyor

• US 20040144623A1
• Filed: 01/29/2003
• Published: 07/29/2004
• Est. Priority Date: 01/29/2003
• Status: Active Grant

• Current Assignee: Hytrol Conveyor Company, Inc.
• Original Assignee: Hytrol Conveyor Company, Inc.
• Inventors: Wallace, Paul Dewayne, Bonham, Boyce Dean, Newsom, Gregory Scott, Supine, Anthony John
• Granted Patent: US 6,860,381 B2
• Time in Patent Office: Days
• US Class Current: 198/788
• CPC Class Codes: B65G 43/10 Sequence control of conveyors operating in combination
• CPC Class Codes: B65G 47/261 Accumulating articles

Abstract

An accumulation conveyor system for supporting and moving a plurality of objects. The conveyor system is divided into a plurality of zones wherein each zone includes a top and bottom conveying surface and wherein a space is defined between the top and bottom surfaces. Each zone also includes its own motor positioned external to the space between the conveying surfaces and coupled to the conveying surfaces via a non-slip connection. A control system is connected to the motor and controls the power to the motor so that the conveying surfaces in each zone can be moved independently. Whenever a sensor detects an empty downstream zone, it signals the control system of the upstream zone to power the motor and move the object to fill the empty zone. The control system may also be configured to allow a soft start wherein motor speed is increased gradually.

Claims

1. A conveyor system for supporting and moving a plurality of objects, said conveyor system comprising:

a plurality of zones each including a top conveying surface and a bottom surface, wherein the top and bottom surfaces define a space therebetween and wherein the top conveying surface is capable of moving in at least a downstream direction and of supporting one of the objects thereon;

a plurality of electrical motors wherein each of the electrical motors is positioned external to the space between the top and bottom surfaces of a respective one of the plurality of zones and wherein each electrical motor includes a drive shaft operable to drive the top conveying surface; and

a control system operably connected to each of the electrical motors and capable of independently supplying power to each of the electrical motors such that the top conveying surface in one zone, and the object supported thereon, can be moved in the downstream direction independently of the other objects supported within the other zones.

2. A conveyor system of claim 1, wherein each zone has a drive assembly including a non-slip coupling operably connecting the top conveying surface to the drive shaft of the electrical motor.

3. A conveyor system of claim 2, wherein the control system is further capable of controlling acceleration of the top conveying surface by controlling a speed of each of the electrical motors.

4. A conveyor system of claim 3, wherein the control system is further capable of controlling a frequency of power supplied to the motors so as to independently control the speed of each of the motors.

5. A conveyor system of claim 2, wherein the control system is capable of conducting a soft start wherein a speed of the motor is gradually increased.

6. A conveyor system of claim 1, wherein the electrical motors each have an output of at least 0.5 horsepower.

7. A conveyor system of claim 1, wherein the electrical motors each have a torque output of at least 687 in-lb.

8. A conveyor system of claim 1, wherein the top conveying surface is further capable of reverse movement in an upstream direction.

9. A conveyor system of claim 7, wherein the control system is capable of operating the electrical motors in a reverse direction.

10. A conveyor system of claim 1, wherein the top and bottom surfaces in each of the zones are defined by a plurality of rollers.

11. A conveyor system of claim 9, wherein each zone has a drive assembly configured to couple the drive shaft of the electrical motor to a driven one of the rollers and is further configured to slave the other rollers in the zone to the driven roller.

12. A conveyor system of claim 10, wherein the drive assembly includes a non-slip coupling connecting the drive shaft.

13. A conveyor system of claim 11, wherein the drive assembly further includes a chain and sprocket assembly slaving the other rollers to the driven roller.

14. A conveyor system of claim 1, wherein the control system includes a pair of sensors configured to sense the object in its zone.

15. A conveyor system of claim 13, wherein one of the sensors is positioned to detect downstream movement of the object supported on the top conveying surface and the other one of the sensors is positioned to detect upstream movement of the object on the top conveying surface.

16. A conveyor system of claim 14, wherein the one of the sensors is positioned at a downstream end of the zone and the other one of the sensors is positioned at the upstream end of the zone.

17. A conveyor system of claim 15, wherein the sensors are each positioned below the bottom surface.

18. A conveyor system of claim 1, further comprising a single power source and wherein the control system is configured to distribute electrical power from the single power source to the motor in each of the zones.

19. A conveyor system of claim 1, wherein the control system includes a power controller and logic module in each zone and wherein said power controller and logic module cooperate to control the power supplied to the motor of the respective zone.

20. A conveyor system of claim 19, wherein the power controller and logic module has an upstream power and communication connection and a downstream power and communication connection allowing quick connection, and disconnection, of upstream and downstream zones.

21. A conveyor system of claim 19, wherein the power controller and logic module of each zone are further configured to detect current overload of the motor in the zone and reduce power supplied to the motor in response to detecting overload.

22. A conveyor system for supporting and moving a plurality of objects, said conveyor system comprising:

a frame including a pair of laterally spaced support members extending in a machine direction;

a plurality of zones separating the laterally spaced support members into discrete portions, wherein each zone includes a conveying surface extending between, and moveably supported by, the discrete portions of the support members of the zone and wherein one of the rollers in each zone is a drive roller slaved to the other rollers in the zone via a chain and sprocket assembly;

a plurality of electrical motors wherein each of the electrical motors includes a drive shaft operably connected to the conveying surface of a respective one of the zones via a non-slip coupling and wherein each of the motors is supported by one of the support member portions on a side of the support member portion opposite the conveying surface; and

a control system operably connected to each of the electrical motors and capable of independently controlling electrical power supplied to each of the electrical motors such that the conveying surface, and any one of the objects supported thereon, can be moved in the machine direction independently of other objects supported on the conveying surfaces within the other zones.

23. A conveyor system of claim 22, wherein the control system is further capable of controlling a speed of each of the electrical motors.

24. A conveyor system of claim 22, wherein the control system is capable of conducting a soft start wherein a speed of the electrical motor in its respective zone is gradually increased.

25. A conveyor system of claim 22, wherein the electrical motors each have an output of at least 0.5 horsepower.

26. A conveyor system of claim 22, wherein the electrical motors have a torque output of at least 687 in-lb.

27. A method of supporting and conveying a plurality of objects using an accumulation conveyor having a plurality of zones, said conveying method comprising:

supporting the objects on a top conveying surface of the accumulation conveyor;

sensing an empty one of a plurality of zones subdividing the top conveying surface not supporting one of the objects;

moving the conveying surface of an adjacent one of the zones upstream of the empty zone by energizing an electrical motor and transmitting torque from the motor to the conveying surface with negligible slip; and

controlling electrical power supplied to the motor by causing the electrical power to gradually increase so as to move, in a downstream direction, the top conveying surface of the zone upstream, and adjacent to, the empty zone so as to gradually accelerate and move an object from the upstream zone into the empty zone.

28. A method of claim 27, wherein transmitting torque includes transmitting a torque of at least 687 in-lb.

29. A method of claim 27, further comprising reversing movement of the conveying surface so as to move the top conveying surface of the zone downstream, and adjacent to, the empty zone so as to move an object from the downstream zone into the empty zone.

30. A control system for distributing power to a plurality of motors each positioned in a respective one of a plurality of zones of an accumulation conveyor supporting a plurality of objects thereon, said control system comprising:

a plurality of sensors, wherein each of the sensors is positioned in a respective one of the zones and wherein each of the sensors is configured to detect one of the objects supported by the conveyor in the zone;

a plurality of logic modules, wherein each of the logic modules is positioned in a respective one of each of the zones and is coupled in communication with the sensor in an adjacent, downstream one of the zones; and

a plurality of power controllers, wherein each of the power controllers is coupled in communication with the logic module in its respective zone and is configured to activate the motor in its respective zone so as to move any one of the objects in its zone into the downstream, adjacent zone.

31. A control system of claim 30, wherein the power controllers are connected to a single power source.

32. A control system of claim 31, wherein each power controller has an upstream and downstream power connection.

33. A control system of claim 32, wherein the upstream power connection is at the end of a power line.

34. A control system of claim 33, wherein the power controllers are connected serially to the single power source via the power connections.

35. A control system of claim 31, wherein the power controllers are further configured to detect current overload of the motor in each zone and to reduce power supplied to the motor in response to detecting overload.

36. A control system of claim 31, wherein the power controller and logic module are in separate housings.

37. A conveyor system for supporting and moving a plurality of objects, said conveyor system comprising:

a plurality of zones each including a top conveying surface and wherein the top conveying surface is capable of moving in at least a downstream direction and of supporting one of the objects thereon;

a drive system capable of independently supplying power to each of the zones such that the top conveying surface in one zone, and the object supported thereon, can be moved in the downstream direction independently of the other objects supported within the other zones; and

wherein the drive system generates a noise level of less than 18 dbA in excess of a background noise level.

38. A conveyor system of claim 37, wherein the drive system generates a noise level equal to or less than approximately 8 dbA in excess of the background noise level.

39. A conveyor system of claim 37, wherein the drive system further includes a roller-to-roller chain drive.