Patent ID: 7661908
Filing Date: 2010-02-16
Classification: E02D

Abstract:
1. A trench shielding unit comprising: adjustable panels forming first and second walls, each adjustable panel including a channel, a convex edge and a concave edge, the convex edge having a contact face formed in beveled and straight segments, and the concave edge having a contact face formed in opposing beveled and straight segments, the convex edge of a first one of the panels being facially abutting and engaged without fastening in the concave edge of a second one of the panels; a first whaler attached to each panel of the first wall at the corresponding channel, the first whaler having a U-shaped cross section with a corresponding back engagement wall and legs extending perpendicular therefrom; a second whaler attached to each panel of the second wall at the corresponding channel, the second whaler having a U-shaped cross section having a corresponding back engagement wall and legs extending perpendicular therefrom; and at least two spreader bars attached to and extending between the walls; and wherein the engagement of each adjustable panel with its corresponding whaler includes a panel fastener, the panel fastener having a retaining washer fitted in the channel of said corresponding panel, the retaining washer having a hole therein with a threaded section aligned with the hole, and a threaded bolt that includes a head, a shank secured to the head and passing through a one of a plurality of evenly spaced openings along the back engagement wall of the corresponding whaler into said channel, through the hole of the retaining washer and engaged with the threaded section, the head of the bolt forcing the corresponding back engagement wall of the whaler against said channel when secured.