Vibratory classifier apparatus

1. A vibratory classifier comprising:

a first sidewall defining a first plane;

a second sidewall defining a second plane, said first plane separated from said second plane by a distance along a transverse direction;

a vibratory mechanism supported at least partially on said first and second sidewalls, said vibratory mechanism configured to induce vibration of the classifier;

at least a first screen disposed at least partially between said first sidewall and said second sidewall, wherein upon vibration of the classifier, material moves along said first screen in at least a longitudinal direction generally perpendicular to said transverse distance;

a feed box disposed at least partially in an inlet region of the classifier, said inlet region disposed at least partially rearward of said first screen along said longitudinal direction, said feedbox comprising:

a classifying surface having openings therethrough; and

a lower surface disposed at an angle below horizontal, said lower surface being disposed at least partially beneath said classifying surface to receive undersize material that passes through said classifying surface, said lower surface being disposed to transfer said undersize material onto said first screen,

 wherein said lower surface is pivotable between an operating position and a maintenance position; wherein in said maintenance position an access opening is disposed between said lower surface and said classifying surface, wherein said access opening permits access to a rear portion of said first screen.

2. The vibratory classifier of claim 1 , wherein said feedbox further comprises:

first and second transversely spaced feedbox walls, wherein said lower surface is pivotally coupled to each of said feedbox walls.

3. The vibratory classifier of claim 2 , wherein said feedbox further comprises:

a link, wherein said link at least partially supports said lower surface in said maintenance position.

4. The vibratory classifier of claim 3 , wherein said link comprises a slotted link.

5. The vibratory classifier of claim 3 , wherein said link is disposed adjacent to one of said first and second feedbox walls.

6. The vibratory classifier of claim 1 , wherein said feedbox further comprises:

a link, wherein said link at least partially supports said lower surface in said maintenance position.

7. The vibratory classifier of claim 1 , further comprising:

a second screen disposed above said first screen, said first screen at least partially supported by said first and second sidewalls.

8. The vibratory classifier of claim 7 , wherein said classifying surface is disposed adjacent to and rearwardly of said second screen.

9. The vibratory classifier of claim 7 , wherein said classifying surface is disposed to transfer oversize material onto said second screen.

10. A method of operating a material classifier, comprising:

in an operational mode:

receiving material onto a classifying surface of a feedbox;

transferring a first material subset comprising oversize material passing over said classifying surface onto a first classifying screen adjacent to said feedbox;

receiving a second material subset comprising undersize material passing through said classifying surface onto a lower surface disposed at least partially beneath said classifying surface;

transferring said second material subset across said lower surface onto a second classifying screen adjacent to said feedbox;

in a maintenance mode:

pivoting said lower surface from an operating position downward into a maintenance position to create an access opening between said classifying surface and said lower surface; and

accessing said second classifying screen via said access opening.

11. The method of claim 10 , further comprising:

selectively locking and unlocking said lower surface in said operating position.

12. The method of claim 10 , further comprising:

by a link coupled to a sidewall of the feedbox, at least partially supporting said lower surface in said maintenance position.