Security for grate covering underground air vents

Apparatus for securing a grating over an atmospheric opening of a ventilation shaft fluidly communicating to an underground ventilation duct, said grating having parallel horizontal load bearing bars and cross bars between and transverse to the load bearing bars that connect adjacent load bearing bars, said bars having a top surface, adjacent load bearing bars and adjacent cross bars defining open air passage cells between them, said apparatus comprising:

• a quadrilateral support comprising opposed lateral sidewalls for arrangement in said shaft defining a passage between top and bottom openings of the support for fluid communication of said ventilation duct up through said support to said atmospheric opening, said support further comprising horizontal flanges transverse to said sidewalls for projecting across a top of said shaft to hang said support in said shaft covered by said grating,
• a beam supported on a pair of opposed lateral sidewalls of said support, said beam having a top side and unobstructively horizontally spanning said passage proximate said top opening at a level below said flanges
• at least one anchoring member connected to said top side of said beam oriented in the direction of said beam and at a level below said flanges, and
• at least one clip for each grating section, each clip comprising
• one or more outwardly extending wings for engaging the top surface of adjacent bearing bars or adjacent cross bars of the grating,
• a vertical aperture adjacent said one or more wings, and
• a fastener insertable into or captive within said aperture of said clip and connectable to said anchoring member to secure said clip and said grating to said anchoring member.

A process for securing a grating over a ventilation shaft to an underground ventilation duct fluidly communicating through the ventilation shaft to an atmospheric opening of the shaft, said grating comprising parallel load cross bars and cross bars that connect the load cross bars, said bars having a top surface and defining an open air passage cells between adjacent bars, comprising:

• a) providing
• (1) in said shaft a support comprising horizontal flanges projecting across a top of at least two opposing sides of said shaft to hang said support in said shaft covered by said grating, said support defining a passage between top and bottom openings of the support for fluid communication of said ventilation duct up through said support to said atmospheric opening,
• (2) a beam having ends and a top side, said beam unobstructively horizontally spanning across said passage supported at said ends on opposed sides of said support at a level below said flanges and proximate said top opening,
• (3) at least one vertical rail having a top side and bottom side and a front side and backside, connected at said bottom side to said top side of at least a portion of said beam, and horizontally parallel to said beam,
• (4) a clamp having a threaded horizontal aperture and a threaded vertical aperture,
• (5) a threaded fastener for said threaded horizontal aperture of said clamp,
• (6) a clip comprising a recessed central area with a centered vertical aperture and outwardly extending wings, and
• (7) a threaded fastener for said vertical aperture of said clamp,
• b) identifying at least one cell in said grating section that would be vertically above said rail when said grating section is placed onto said support,
• c) positioning said clamp on the rail so the threaded horizontal aperture is perpendicular to the rail and the vertical threaded aperture is vertically over the rail, steps b) and c) being conducted either (i) step b) before step c), or (ii) step c) before step b),
• d) inserting said threaded fastener for said threaded horizontal aperture of said clamp in said threaded horizontal aperture and tightening it to affix said clamp to said rail,
• e) placing said grating onto said support such that said identified cell of the grating is vertically directly over said vertical aperture of said clamp,
• f) placing said recessed central area of the clip in said identified cell of said grating to engage said outwardly extending wings with the top surface of at least the adjacent cross bars,
• g) determining whether said vertical aperture in said recessed central area of said clip is directly aligned with said vertical aperture of said clamp, and if so, proceeding to step (h), but if not, loosening said clamp and moving it linearly along said rail or transversely to said rail, or both, and refastening said clamp to said rail,
• h) inserting said threaded fastener for said threaded vertical aperture of said clamp into said vertical aperture of said clip and screwing such threaded fastener into said directly aligned vertical aperture of said clamp until the clip secures said grating to said clamp.

A process for securing a grating over a ventilation shaft to an underground ventilation duct fluidly communicating through the ventilation shaft to an atmospheric opening of the shaft, said grating comprising parallel load bearing bars and cross bars that connect the load bearing bars, said bars having a top surface and defining a open cell between adjacent bars, wherein a support comprising horizontal flanges projecting across a top of at least two opposing sides of said shaft hangs said support in said shaft covered by said grating, said support defining a passage between top and bottom openings of the support for fluid communication of said ventilation duct up through said support to said atmospheric opening, and wherein a beam having ends and a top side unobstructively horizontally spans across said passage supported at said ends on opposed sides of said support at a level lower than said flanges and proximate said top opening, and wherein at least one vertical rail having a top side and bottom side and a front side and a backside is connected at said bottom side to said top side of at least a portion of said beam horizontally parallel to said beam, said process comprising

• (a) identifying a cell in said grating that would be vertically above said rail when said grating is placed onto said support,
• (b) providing an inverted U-clamp comprising a unitary base and a pair of spaced arms vertical to said base and terminating in ends, a first said arm including a threaded horizontal aperture between said base and the end of said first arm and said base including a threaded vertical aperture between said arms,
• (c) determining a location along a length of said rail that would be vertically directly under said identified cell of said grating when said grating is placed onto said support,
• (d) positioning said inverted U-clamp at said determined place along the length of said rail with said first arm of said U-clamp outside said front side of said rail, with a second arm of said inverted U-clamp outside said backside of said rail, and with said base of the inverted U-clamp straddling said top side of said rail, said ends of said arms moveably supported on said beam,
• (e) screwing a threaded set screw into said threaded horizontal aperture of said first arm to apply set screw tip pressure against said front side of said rail effective to fix said clamp to said rail,
• (f) placing said grating onto said support such that said identified cell of the grating section is vertically directly over said vertical aperture of said inverted U-clamp,
• (g) providing a clip comprising a recessed central area with a centered vertical aperture and outwardly extending wings,
• (h) placing said recessed central area of said clip in said identified cell of said grating section to engage said outwardly extending wings with the top surface of at least the adjacent load bearing bars,
• (i) determining whether said vertical aperture in said recessed central area of said clip is directly aligned with said vertical aperture of said base of said inverted U-clamp, and if so, proceeding to step (j), but if not,
• (1) unscrewing said set screw a few turns to release the tip pressure on said front side of said rail, and
• (2) either,
• (A)(x) before or after step (i)(1) selecting a shim of thickness effective to move the vertical aperture of the base of the inverted U-clamp away from the front side of the rail enough to align such vertical aperture directly under the vertical aperture of the clip,
• (y) after step (i)(1) and step (A)(x) placing said shim between said backside of said rail and said second arm of said inverted U-clamp, and
• (z) rescrewing said set screw in said threaded horizontal aperture of said first arm to reapply set screw tip pressure against said front side of said rail effective to fix said shimmed clamp to said rail, or
• (B)(xx) moving said clamp linearly along said rail enough to linearly align such vertical aperture directly under the vertical aperture of the base of the clip, and
• (yy) rescrewing said set screw in said threaded horizontal aperture of said first arm to reapply set screw tip pressure against said front side of said rail effective to fix said linearly aligned clamp to said rail, or
• (C) performing a combination of steps (i)(1)(A)(x) and (y) and (i)(1)(B)(xx), and then rescrewing said set screw in said threaded horizontal aperture of said first arm to reapply set screw tip pressure against said front side of said rail effective to fix said shimmed and linearly aligned clamp to said rail,
• (j) providing a fastening member having a head of larger diameter than said centered vertical aperture of said clip and a threaded shank insertable in said centered vertical aperture of said clip and receivable in said vertical aperture of said base of said clamp, and,
• (k) inserting said fastening member into said vertical aperture of said clip and screwing said fastening member into said directly aligned vertical aperture of said base of said clamp until the clip secures said grating section to said inverted U-clamp.

Apparatus for securing a grating over an atmospheric opening of a ventilation shaft having opposing sides, said grating comprising parallel horizontal load bearing bars and cross bars between and transverse to the load bearing bars that connect the load bearing bars, said bars having a top surface, adjacent load bearing bars and adjacent cross bars defining open air passage cells between them, said apparatus comprising:

• a vertically extending support for arrangement in said shaft comprising horizontal flanges for projecting across a top of at least two opposing sides of said shaft to hang said support in said shaft covered by said grating,
• a beam having a top side and supported by and spanning between a pair of opposed lateral sidewalls of said support at a level below said flanges,
• at least one anchoring member connected to said top side of said beam,
• at least one clamp means for clamping to said anchoring member, and
• at least one grating hold-down connecting to the clamp means to secure said hold-down and said grating to said anchoring member.