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CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of U.S. application Ser. No. 13/413,379 filed on Mar. 6, 2012, which is a continuation in part of U.S. application Ser. No. 12/775,817, filed May 7, 2010, now abandoned, the disclosures of which are incorporated herein by reference for all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to temporary guardrails and, more particularly, to an apparatus for erecting a temporary guardrail on a stair. 
       BACKGROUND OF THE INVENTION 
       [0003]    Typically, stairs, particularly of the type in apartment buildings and the like, comprise three major components: stringers, treads and risers, although in certain stair constructions; e.g., pan stairs, there are no risers, open space is being formed between the treads. The stringers can be made of a steel channel beam, wood, etc., the dimensions of which can vary depending upon the load to be carried. As is well known, the treads are the generally horizontal portions of the stair, while the risers are the vertical portions connecting the treads. 
         [0004]    Because of safety concerns during construction or remodeling, it is generally necessary, before a permanent handrail or guardrail is installed, to erect a temporary guardrail or handrail, and thereby minimize the chance of injuries from a construction worker falling off the stair. 
       SUMMARY OF THE INVENTION 
       [0005]    One object of the present invention is to provide an assembly for erecting a temporary guardrail on a stair. 
         [0006]    Another object of the present invention is to provide an apparatus for erecting a temporary guardrail on a stair, which can be quickly assembled and disassembled, as needed. 
         [0007]    In one aspect, the present invention comprises a stanchion or other elongate member, first and second, spaced jaws connected to the stanchion, which are adapted to rigidly connect the stanchion to the stringer in such a manner that the stringer is substantially perpendicular to the pitch of the stair. 
         [0008]    The apparatus of the present invention can further comprise, at least one bracket which can receive a temporary handrail; e.g., a 2×4 or the like. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an elevational view of the front side of one embodiment of the apparatus of the present invention. 
           [0010]      FIG. 2  is an elevational, side view of the apparatus shown in  FIG. 1 . 
           [0011]      FIG. 3  is an elevational view of the back side of the apparatus of  FIGS. 1 and 2 . 
           [0012]      FIG. 4  is an isometric, environmental view of a temporary guardrail attached to a stair stringer, using one embodiment of the apparatus of the present invention. 
           [0013]      FIG. 5  is a cross-sectional view taken along the lines  5 - 5  of  FIG. 4 . 
           [0014]      FIG. 6  is a cross-sectional, view of another embodiment of the jaw assembly portion of  FIG. 4 . 
           [0015]      FIG. 7  is an elevational view of the front side of the embodiment shown in  FIG. 6 . 
           [0016]      FIG. 8  is a cross-sectional view taken along the lines  8 - 8  of  FIG. 6 . 
           [0017]      FIG. 9  is a cross-sectional view taken along the lines  9 - 9  of  FIG. 6 . 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0018]    Referring first to  FIGS. 1-3 , the apparatus of the present invention, shown generally as  10 , comprises a metal tubular member or stanchion  12 , having a front side  14 , a first side  16 , a second, opposite side (not shown), and a back side  18  ( FIG. 3 ). Located generally near the lower end of the stanchion  12  is a first jaw assembly shown generally as  20 , a second jaw assembly shown generally as  22  being spaced longitudinally from first jaw assembly  20  in a direction toward the upper end of stanchion  12 . 
         [0019]    With reference to  FIG. 5 , the details of construction of jaw assemblies  20  and  22  are shown. Bottom jaw assembly  20  comprises an L-shaped head portion having a flange portion  24  and a leg portion  26  attached thereto, a threaded shank  28  extending from leg portion  26  and through registering bores  31  and  30  in the front and back sides  14  and  18 , respectively. A wing nut  32  is threadedly received on the portion of shank portion  28  extending out of bore  30 , a washer  34  being positioned between wing nut  32  and back surface  18 . In effect, threaded shank  28  and wing nut  32  comprise a compression assembly for a purpose described hereafter. Second jaw assembly  22  also comprises an L-shaped head portion having a flange portion  36 , a leg portion  38 , a threaded shank portion  40  extending from leg portion  38  through registering bores  42  and  43  in stanchion  12 . A wing nut  44  is threadedly received on the portion of threaded shank  40  extending through back side  18  of stanchion  12 . As can be seen, stanchion  12  has a plurality of registering bores  42  and  43 , through which threaded shank  40  can extend to allow jaw assembly  22  to be adjustable longitudinally along stanchion  12 . To provide strength, a channel shaped spacer  60 , effectively a washer, can be used, the spacer  60  overlying the plurality of bores on the back side  18  of stanchion  12 . 
         [0020]    As can be seen,  FIG. 5  is a cross-sectional view taken along the lines  5 - 5  of  FIG. 4  and accordingly, shows a portion of a stair assembly. The stair assembly comprises treads  46  and risers  48 , which are attached in a suitable fashion to stringers  50 ,  51  which support the stair. For purposes of the following description, the detailed construction of only one of the stringers of the apparatus of the present invention will be described. Further, although a stair with two stringers is shown, it will be apparent that many stairs are constructed against a wall so that only one stringer would have a guardrail. Furthermore, although the stairs shown have risers, as noted above, in the case of pan stairs there are no risers. As can be seen in  FIG. 4 , the stringers  50 ,  52  act as side supports for the stair and are generally at the desired pitch of the stairs. Stringer  50  comprises a channel shaped metal beam, having a main beam portion  52  and spaced, laterally extending flanges  54  and  56 . As can be seen in  FIG. 5 , flanges  54  and  56  space beam portion  52  from stanchion  12 . It will be appreciated that the stringer  50  need not be channel-shaped but could be a square tubular member, a wooden beam, etc., but in any event, would have a surface  58  spaced from stanchion  12 . 
         [0021]    As can be seen in  FIG. 5 , stringer  50  is received between first and second jaw assemblies  20  and  22 , such that flange portion  24  abuts the side  58  of stringer beam portion  52  adjacent flange portion  54  and that flange portion  36  abuts the side  58  of stringer beam portion  52  adjacent flange portion  56 . Further, when so positioned, it can be seen that by tightening wing nuts  32  and  44 , flanges  24  and  36 , respectively, will urge stanchion  12  toward stringer  50 , stanchion  12  being compressed against the outer edges  54   a  and  56   a  of flanges  54  and  56  of stringer  50 , thereby rigidly securing stanchion  12  to stringer  50 , the outer surface of flange  54  forming a bottom edge of stringer  50 , the outer surface of flange  56  forming a top edge. 
         [0022]    With reference to  FIGS. 1-4 , it can be seen that the apparatus of the present invention is provided with first and second brackets or tubular members  70  and  72 , which are affixed to stanchion  12  by means of bolts  74  and  76 , respectively, which extend through registering bores  80 ,  82  in the front side  14  and back side  18  of stanchion  12 . Although brackets  70  and  72  are shown as tubular, they could be L-shaped in construction or for that matter, any other form, the only proviso being that they be adapted to support a temporary guardrail; e.g., a 2×4. As shown, 2×4 temporary rails  84  and  86  are received in brackets  70  and  72 , respectively, the rails being secured to the brackets  70  and  72  by fasteners  90  and  92 ; e.g., a screw, nail or the like, extending through holes  78 ,  79  of brackets  70 ,  72 , respectively. Threaded wing nuts  75  and  77  are received on bolts  74  and  76 , respectively, to secure brackets  70  and  72 , respectively, to stanchion  12 . It will be appreciated from the above description that jaws  20 ,  22  and brackets  70  and  72  are rotatable with respect to stanchion  12 , such that they can be disposed at any desired angle, if necessary, to accommodate and provide rails which are at any desired angle. However, typically the guardrails are at an angle the same as the angle of the pitch line of the stair, as shown in  FIG. 4 . 
         [0023]    As is the case with jaw assembly  22 , it can be seen that brackets  70  and  72  can be longitudinally adjusted along stanchion  12  by virtue of a plurality of registering bores, such as  80  and  82 . 
         [0024]    Referring now to  FIGS. 6-9 , there is seen another embodiment of the jaw assembly, shown generally as  120 . Jaw assembly  120  comprises an L-shaped head portion having a flange portion  124 , a leg portion  126  attached thereto, and a threaded shank  128  extending from leg portion  126 . Registering bores  131  and  130  are in the front and back sides  14  and  18 , respectively of the stanchion  12 . Leg portion  126  extends through bore  131  and shank portion  128  extends through bore  130 . Wing nut  32  is threadedly received on the portion of shank  128  extending out of bore  130 , to form a compression assembly. 
         [0025]    Leg portion  126  and bore  131  have cross-sectional shapes such that rotation of the leg portion is prevented relative to the bore. As shown in  FIGS. 6-9 , leg portion  126  and bore  131  both have rectangular cross-sections, however, it will be understood that any cross-sectional shapes which prevent relative rotation to one another are within the scope of the invention. Leg portion  126  and bore  131  can be keyed together and complementary or not. Leg portion  126  and bore  131  may have different cross-sectional shapes so long as their respective cross-sections prevent relative rotation when leg portion  126  is extended through bore  131 . Leg portion  126  need not have a uniform cross-section. It is contemplated that at least a portion of leg portion  126  will extend through bore  131 . In some embodiments though, leg portion  126  may have a uniform cross-section, thus allowing the entire leg portion to extend through bore  131 . 
         [0026]      FIG. 6  illustrates a bottom jaw assembly, but it will be understood that the embodiment of  FIG. 6  could be used in place of any of the jaw assemblies described herein. 
         [0027]    The above description is intended in an illustrative rather than a restrictive sense, and variations to the specific configurations described may be apparent to skilled persons in adapting the present invention to other specific applications. Such variations are intended to form part of the present invention insofar as they are within the spirit and scope of the claims below.

Summary:
An apparatus for use in erecting a temporary guardrail on a stair, having a stair stringer. The apparatus has an elongated stanchion. A first jaw assembly is operatively attached to the stanchion for engaging one side of the stringer, proximal the bottom edge thereof, and includes a first compression assembly to operatively urge the stanchion against the stringer. A second axially spaced, jaw assembly is operatively attached to the stanchion for engaging the one side of the stringer proximal a top edge thereof, and includes a second compression assembly to urge the stanchion against the stringer, and a bracket attached to the stanchion, and being adapted to receive a temporary guardrail member.