Bin tunnel with collapsible sides

1. A bin tunnel for use with a truck box of a truck to load content into said truck box using a bin that is sized to fit into said bin tunnel, said bin tunnel comprising an outer portion being a front, a top and two sides and an inner portion with a lift mechanism mounted on an inner wall thereof, said inner wall being fixed, said outer portion being slidably supported on said truck box to enable said outer portion to be moved outward from said truck box to an open position of said bin tunnel and moved inward to a closed position of said bin tunnel in which said front is substantially flush with an outer side wall of said truck box, said outer portion of said bin tunnel being supported on said truck box independently of said sides, said sides being collapsible relative to said front, in said open position said bin tunnel having sufficient height, depth and width to receive said bin, a lower end of said bin tunnel being vertically supported by two slidable beams that slide in and out beneath a floor of said truck box as said bin tunnel slides in to said closed position and out to said open position respectively, said lift mechanism being constructed to removably connect to said bin and to raise said bin upward within the bin tunnel and tilt the bin to empty the contents of said bin into the truck box, a depth of said bin tunnel in said closed position being substantially less than fifty (50) percent of a depth of the bin tunnel in said open position, said sides being extended in said open position and retracted in said closed position.

2. A bin tunnel as claimed in claim 1 wherein access to said truck box through said bin tunnel is closed off when said bin tunnel is in said closed position.

3. A bin tunnel as claimed in claim 2 wherein said sides are bifold panels that fold substantially in half when said bin tunnel is in said closed position and extend fully outward when said bin tunnel is in said open position.

4. A bin tunnel as claimed in claim 2 wherein said bin tunnel has two drawer slides near said top, said drawer slides extending into said truck box.

5. A bin tunnel as claimed in claim 2 wherein a depth of said bin tunnel is a distance between said inner wall and said front, said depth when said bin tunnel is in said closed position being less than forty (40) percent of said depth when said bin tunnel is in said open position.

6. A bin tunnel as claimed in claim 2 wherein said depth when said bin tunnel is in said closed position is less than thirty (30) percent of said depth when said bin tunnel is in said open position.

7. A bin tunnel as claimed in claim 6 wherein when said bin tunnel is in said closed position, a space between said lift mechanism and said front is substantially occupied by said side walls.

8. A bin tunnel as claimed in claim 1 wherein said bin tunnel has a footprint in said closed position that is less than forty (40) percent of a footprint of said bin tunnel when said bin tunnel is in said open position.

9. A bin tunnel used with a truck box of a truck to load content from a bin into said truck box, said bin being sized to fit within said bin tunnel on a lift mechanism that can raise and tip said bin, said bin tunnel being located on a side of said truck box and comprising a fixed inner wall, two sidewalls and an outer wall with slidable supports to enable said sidewalls and said outer wall to be moved outward and inward relative to said inner wall between an open position and a closed position respectively, said slidable vertically supports at a lower end of said bin tunnel being two slidable beams that slides in and out beneath a floor of said truck box as said bin tunnel slides in to said closed position and out to said open position respectively, said side walls being collapsible so that a depth of said bin tunnel in said closed position is significantly less than a depth of said bin tunnel in said open position, said bin fitting within said bin tunnel when said bin tunnel is in said open position, said lift mechanism being mounted on said inner wall, said inner wall being a recessed wall of the truck box, said outer wall being substantially flush with a side of said truck box when said bin tunnel is in said closed position.

10. A bin tunnel for use with a truck box of a truck to load content from a bin into said truck box, said bin being located in a side of said truck box, said bin being sized to fit into said bin tunnel when said bin tunnel is in an open position, said bin tunnel comprising a fixed inner wall, an outer wall, and two side walls with slidable supports to move said outer wall and side walls between a closed position and said open position relative to said inner wall, said slidable vertically supports at a lower end of said bin tunnel being two slidable beams that slides in and out beneath a floor of said truck box as said bin tunnel slides in to said closed position and out to said open position respectively, said side walls being collapsible so that a distance between said inner wall and said outer wall when said bin tunnel is in said closed position is substantially less than a distance between said inner wall and said outer wall when said bin tunnel is in said open position.

11. A bin tunnel as claimed in claim 10 wherein said distance when said bin tunnel is in said closed position is substantially less than half of said distance when said bin tunnel is in said open position.

12. A bin tunnel as claimed in claim 11 wherein said distance when said bin tunnel is in said closed position is substantially one third (⅓) of said distance when said bin tunnel is in said open position.

13. A bin tunnel as claimed in claim 11 wherein said distance when said bin tunnel is in said closed position is substantially twenty-seven percent (27%) of said distance when said bin tunnel is in said open position.

14. A bin tunnel as claimed in claim 9 wherein said inner wall is recessed inside of said side of said truck box by substantially thirteen (13) inches, being a sufficient distance to accommodate said elevator and said sidewalls in a retracted position when said bin tunnel is in said closed position.

15. A bin tunnel as claimed in claim 9 where said bin tunnel has two drawer slides near said top, said drawer slides extending into said truck box, said bin tunnel being manually operable between said open position and said closed position.