Trench box safety ladder
Various embodiments of the present invention relate to trench box safety ladders and methods of constructing trench boxes with safety ladders. In one embodiment, a trench box comprises two side walls with a plurality of supports between the two walls, a built-in ladder within the inner face of a side wall, and an extension ladder positioned on the top face of the side wall.
1. A trench box comprising:
two side walls forming a working space between the side walls, each side wall comprising an inner face and a top face, wherein one side wall comprises a cavity;
a built-in ladder positioned within the cavity, wherein the built-in ladder comprises a plurality of spaced apart rungs that do not extend beyond the plane of the inner face of the side wall comprising the cavity; and
an extension ladder positioned on the top face of the side wall in proximity to the built-in ladder.
2. The trench box of claim 1 , further comprising a plurality of rods connecting the two side walls to each other.
3. The trench box of claim 1 , wherein the extension ladder is positioned in proximity to a top of the built-in ladder.
4. The trench box of claim 1 , wherein the extension ladder is detachable from the trench box.
5. The trench box of claim 1 , wherein the extension ladder extends three feet above the trench box.
6. The trench box of claim 1 , wherein the extension ladder extends three feet above a top of an excavation site in which the trench box is positioned.
7. The trench box of claim 1 , further comprising a receiving structure positioned on the top face of the side wall, wherein the extension ladder is inserted into the receiving structure.
8. The trench box of claim 7 , wherein the receiving structure comprises an opening and a sleeve.
9. The trench box of claim 1 , further comprising a pivoting device, wherein the pivoting device attaches the extension ladder to the top face of the side wall.
10. The trench box of claim 9 , wherein the pivoting device is adapted to allow the extension ladder to be rotated from an open position to a closed position.
11. The trench box of claim 1 , further comprising at least one storage compartment, the storage compartment being located within an interior of a side wall, wherein the storage compartment is accessed from the top face of the side wall.
12. The trench box of claim 11 , further comprising a top cover plate secured to the top face of the side wall via a hinge.
13. A method of retrofitting a trench box with a safety ladder, the trench box comprising a first side wall and a second side wall, each side wall having an inner face, an outer face, a top face, and two end faces, the method comprising:
forming a cavity by removing an inner face section of the first side wall, the cavity comprising cavity sides;
attaching a plurality of rungs to the cavity sides;
forming at least two openings in the top face of the first side wall, wherein the two openings are in proximity to the cavity;
inserting a sleeve into each opening; and
attaching the sleeves to the first side wall top face, wherein the sleeves are adapted to receive an extension ladder.
14. The method of claim 13 , further comprising inserting an extension ladder into the sleeves.
15. The method of claim 13 , further comprising
attaching a storage compartment to the first side wall.
16. The method of claim 13 , wherein the first and second side walls comprise hollow spaces between the inner faces and outer faces.
17. The method of claim 13 , wherein the first and second side walls comprise a steel frame with steel plates welded to the inner face and the outer face.
18. The method of claim 13 , further comprising
attaching a pivoting device to the top face of the first side wall, wherein the pivoting device is adapted to be attached to an extension ladder.