Apparatus for Forming Temporary Guardrails on Stairs

A temporary guardrail system for a stair having a stringer web forming first engagement surface, a bottom stringer flange and a top stringer flange, said bottom stringer flange and said top stringer flange forming second and third spaced engagement surfaces, respectively, said mounting apparatus comprising:

• an elongated stanchion having a front side and a back side;
• a first front bore in said front side of said stanchion and a first back bore in said back side of said stanchion, said first front and back bores forming a first registering pair of bores;
• a first jaw assembly operatively attached to said stanchion, said first jaw assembly including a first head portion adapted to operatively engage said first engagement surface of said stair stringer proximal said bottom stringer flange thereof and a first leg portion attached to said first head portion, said first leg portion extending through said first registering pair of bores and connected to a first compression assembly operative to apply a compressive force to the back side of said stanchion to urge said stanchion against the second engagement surface of said stringer;
• a second front bore in said front side of said stanchion and a second back bore in said back side of said stanchion, said second front and back bores forming a second registering pair of bores, said second registering pair of bores being axially spaced from said first registering pair of bores;
• a second, spaced jaw assembly, operatively attached to said stanchion, said second jaw assembly including a second head portion adapted to operatively engage said first engagement surface of said stringer proximal said top stringer flange thereof and a second leg portion attached to said second head portion, said second leg portioned extending through said second registering pair of bores and connected to a second compression assembly attached to said second head portion and operative to apply a compressive force to the back side of said stanchion to urge said stanchion against the third engagement surface of said stringer, whereby no portion of said mounting apparatus is within the area between said top stringer flange and said bottom stringer flange and no holes are formed in said stringer web to connect said mounting apparatus;
• at least one bracket operatively attached to said stanchion and axially spaced from said second jaw, said bracket being adapted to receive a temporary rail member;
• and
• a rail member received in said bracket.