Conveyor system switch using tubular linear induction motor

• US 6,354,224 B1
• Filed: 05/05/2000
• Issued: 03/12/2002
• Est. Priority Date: 05/06/1999
• Status: Expired due to Fees

• Current Assignee: Jervis B Webb Company (Daifuku Company Limited)
• Original Assignee: Jervis B Webb Company (Daifuku Company Limited)
• Inventors: Ball, Edward E., Devnani, Deepak
• Primary Examiner(s): Morano, S. Joseph
• Assistant Examiner(s): Olson, Lars A.
• Application Number:
  US09/564,810
• Time in Patent Office: 676 Days
• Field of Search: 104/130.01, 104/130.03, 104/130.06, 104/96, 104/102, 104/104, 104/105, 104/130.11, 246/225, 246/226, 246/227, 246/231, 246/253
• US Class Current: 104/130.01
• CPC Class Codes: B61L 23/005 Automatic control or safety means for points for operator-less railway, e.g. transportation systems
• CPC Class Codes: E01B 25/26 Switches; Crossings

Abstract

A conveyor switch for a conveyor track comprising a tubular linear induction motor as the switch drive. A switch tongue is adapted to be pivoted between first and second positions on the conveyor track and has a driving arm extending from one end thereof. The switch drive is operatively connected to the driving arm for driving the switch tongue, wherein the switch tongue is adapted to direct a moving conveyor component between first and second paths of travel on the conveyor track. Various means are provided to account for the linear movement of the switch drive in relation to the arcuate movement of the switch tongue. The switch assembly is especially adapted for switches in power and free conveyor systems.

Claims

1. A method of directing a moving conveyor component between first and second paths of travel, comprising:

activating an electromagnetic field within a linear induction motor having a stationary primary and a moving secondary;

causing said field to move linearly along said stationary primary and to interact with currents induced within said moving secondary;

moving said moving secondary in a linear direction in relation to said stationary primary, between an extended position and a retracted position, wherein said moving secondary is physically linked to a drive arm extending from a switch member for moving said conveyor component;

driving said switch member between first and second positions using said linear induction motor physically linked to said switch member;

causing said conveyor component to be switched between said first and second paths of travel by said switch member, wherein the link between said drive arm and said moving secondary is adapted such that the arcuate movement of said switch member about a pivot point in relation to said linear movement of said moving secondary is accommodated thereby; and

selectively energizing a holding coil mounted adjacent said stationary primary of said motor, and retaining said moving secondary in said extended or retracted position.

2. The method of claim 1, further comprising allowing said linear induction motor to rotate to accommodate the linear movement of said moving secondary in relation to the arcuate movement of said switch member.

3. The method of claim 1, further comprising allowing said linear induction motor to rotate by connecting said motor to a trunnion having first and second pivot pins, wherein the linear movement of said moving secondary in relation to the arcuate movement of said switch member can be accommodated thereby.

4. The method of claim 1, further comprising allowing said moving secondary to pivot in relation to said drive arm via a coupling located on said moving secondary, wherein the linear movement of said moving secondary in relation to the arcuate movement of said switch member can be accommodated thereby.

5. The method of claim 1, further comprising causing said moving secondary to move linearly along a guide bar, and allowing said moving secondary to move in relation to said drive arm, such that the linear movement of said moving secondary in relation to the arcuate movement of said switch member can be accommodated thereby.

6. A conveyor switch for directing a moving conveyor component between two paths of travel, comprising:

a switch member adapted to be pivoted about a pivot point between first and second positions, said switch member having an engaging portion for engaging said conveyor component and a drive arm extending therefrom;

a linear induction motor for driving said switch member between said first and second positions, said linear induction motor comprising a stationary primary and a moving secondary adapted to move linearly between an extended position and a retracted position, and at least one holding coil capable of being selectively energized to retain said moving secondary in said extended or retracted position; and

wherein said moving secondary is connected to said drive arm, and wherein said connection is adapted such that the arcuate movement of said switch member about said pivot point in relation to said linear movement of said moving secondary is accommodated thereby.

7. The switch of claim 6, wherein said motor is rotatably mounted, and the connection between said moving secondary and said drive arm pivots, such that the arcuate movement of said switch member in relation to said linear movement of said moving secondary is accommodated thereby.

8. The switch of claim 7, wherein said motor is rotatably mounted on a plate with a pivot pin having a vertical axis extending through the center of said moving secondary.

9. The switch of claim 6, wherein said motor is mounted on a rotatable trunnion, and the connection between said moving secondary and said drive arm pivots, such that the arcuate movement of said switch member in relation to said linear movement of said moving secondary is accommodated thereby.

10. The switch of claim 9, wherein said motor is mounted on a trunnion tube having two pivot pins extending upward and downward in relation to said motor, said pivot pins having a common vertical axis extending through the center of said moving secondary.

11. The switch of claim 6, wherein a movable coupling is provided on the connection between said moving secondary and said drive arm such that the arcuate movement of said switch member in relation to said linear movement of said moving secondary is accommodated thereby.

12. The switch of claim 6, wherein a guide bar is provided to guide said moving secondary along a linear path, and wherein the connection between said moving secondary and said drive arm enables said moving secondary to move in relation to said drive arm, such that the arcuate movement of said switch member in relation to said linear movement of said moving secondary is accommodated thereby.

13. A conveyor switch for directing a moving conveyor component between two paths of travel, comprising:

a pivoting switch member adapted to be moved between first and second positions, said switch member having an engaging portion for engaging said conveyor component and a drive arm extending therefrom;

a linear induction motor for driving said switch member between said first and second positions, said linear induction motor comprising a stationary primary and a moving secondary adapted to move linearly within said primary, wherein said moving secondary is adapted to move between an extended position and a retracted position, and is connected to said drive arm in a manner which drives said switch member between said first and second positions, while accommodating the linear movement of said moving secondary in relation to the arcuate movement of said pivoting switch member, and said motor has at least one holding coil capable of being selectively energized to retain said moving secondary in said extended or retracted positions.

14. The switch of claim 13, wherein said drive arm moves along an arcuate path between said first and second positions, and wherein said motor is rotatably mounted to accommodate the arcuate movement of said drive arm in relation to said linear movement of said moving secondary.

15. The switch of claim 13, wherein said drive arm moves along an arcuate path between said first and second positions, and wherein said motor is rotatably mounted on a trunnion to accommodate the arcuate movement of said drive arm in relation to said linear movement of said moving secondary.

16. The switch of claim 13, wherein said drive arm moves along an arcuate path between said first and second positions, and wherein a coupling is provided on the connection between said moving secondary and said drive arm to accommodate the arcuate movement of said drive arm in relation to said linear movement of said moving secondary.

17. The switch of claim 13, wherein said drive arm moves along an arcuate path between said first and second positions, and wherein a guide bar is provided to guide said moving secondary in said linear direction, wherein the connection between said drive arm and said moving secondary enables said moving secondary to move in relation to said drive arm to accommodate the arcuate movement of said drive arm in relation to said linear movement of said moving secondary.

18. A method of directing a moving conveyor component between first and second paths of travel, comprising:

activating an electromagnetic field within a linear induction motor having a stationary primary and a moving secondary;

causing said field to move linearly along said stationary primary and to interact with currents induced within said moving secondary;

moving said moving secondary in a linear direction in relation to said stationary primary, between an extended position and a retracted position, wherein said moving secondary is linked to a drive arm extending from a switch member for moving said conveyor component;

driving said switch member between first and second positions using said linear induction motor physically linked to said switch member;

causing said conveyor component to be switched between said first and second paths of travel by said switch member, without the link having to resist the conveyor component, wherein the link between said drive arm and said moving secondary is adapted such that the arcuate movement of said switch member about a pivot point in relation to said linear movement of said moving secondary is accommodated thereby; and

causing said moving secondary to move linearly along a guide bar, and allowing said moving secondary to move along a slot in relation to said drive arm, such that the linear movement of said moving secondary in relation to the arcuate movement of said switch member can be accommodated thereby.

19. A conveyor switch for directing a moving conveyor component between two paths of travel, comprising:

a switch member adapted to be pivoted about a pivot point between first and second positions, said switch member having an engaging portion for engaging said conveyor component and a drive arm extending therefrom;

a linear induction motor for driving said switch member between said first and second positions, said linear induction motor comprising a stationary primary and a moving secondary adapted to move linearly between an extended position and a retracted position;

wherein said moving secondary is connected to said drive arm, and wherein said connection is adapted such that the arcuate movement of said switch member about said pivot point in relation to said linear movement of said moving secondary is accommodated thereby; and

wherein a guide bar is provided to guide said moving secondary along a linear path, and wherein the connection between said moving secondary and said drive arm comprises a slot that enables said moving secondary to move in relation to said drive arm, such that the arcuate movement of said switch member in relation to said linear movement of said moving secondary is accommodated thereby.

20. A conveyor switch for directing a moving conveyor component between two paths of travel, comprising:

a pivoting switch member adapted to be moved between first and second positions, said switch member having an engaging portion for engaging said conveyor component and a drive arm extending therefrom;

a linear induction motor for driving said switch member between said first and second positions, said linear induction motor comprising a stationary primary and a moving secondary adapted to move linearly within said primary, wherein said moving secondary is adapted to move between an extended position and a retracted position, and is connected to said drive arm in a manner which drives said switch member between said first and second positions without having to resist the conveyor component, while accommodating the linear movement of said moving secondary in relation to the arcuate movement of said pivoting switch member; and

wherein said drive arm moves along an arcuate path between said first and second positions, and wherein a guide bar is provided to guide said moving secondary in said linear direction, wherein the connection between said drive arm and said moving secondary is slotted to enable said moving secondary to move in relation to said drive arm to accommodate the arcuate movement of said drive arm in relation to said linear movement of said moving secondary.

21. A conveyor switch for directing a moving conveyor component between two paths of travel, comprising:

a pivoting switch member adapted to be moved between first and second positions, said switch member having an engaging portion for engaging said conveyor component and a drive arm extending therefrom;

a linear induction motor for driving said switch member between said first and second positions, said linear induction motor comprising a stationary primary and a moving secondary adapted to move linearly within said primary between an extended position and a retracted position, and is connected to said drive arm in a manner which drives said switch member between said first and second positions, while accommodating the linear movement of said moving secondary in relation to the arcuate movement of said pivoting switch member; and

wherein said motor is mounted on a rotatable trunnion tube having two pivot pins extending upward and downward in relation to said motor, said pivot pins having a common vertical axis extending through the center of said moving secondary and being connected to upper and lower mounting frames to enable said tube to pivot, and wherein the connection between said moving secondary and said drive arm pivots, such that the arcuate movement of said switch member in relation to said linear movement of said moving secondary is accommodated thereby.