Abstract:
A safety device and methods for providing fall protection during the installation of roofing panels. A moveable safety handrail system includes a pair of safety rails that are supported in a generally horizontal orientation by a plurality of outrigger assemblies. The outrigger assemblies each include a support portion for support of the rail members and a rolling frame portion that engages the purlins of a rooftop structure in rolling contact. The handrail system also features a braking system that prevents inadvertent movement of the handrail device upon the rooftop understructure.

Description:
[0001]    This application claims the priority of U.S. provisional patent application no. 60/362,176 filed Mar. 6, 2002. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The invention relates to a movable safety handrail system for use in installing metal roofing on a building. The invention also relates to methods for safely installing metal panels to a rooftop understructure.  
           [0004]    2. Description of the Related Art.  
           [0005]    A basic metal roof structure uses one or more sheets of insulation atop a series of parallel purlins and metal panels that are laid atop the insulation and then secured to the purlins. The roof structure is installed by workers who typically move from one end of the building to the other, laying down insulation and metal panels as they go.  
           [0006]    The installation of metal building roofs can be a hazardous undertaking for workers as the potential for falls exists. One of the most potentially hazardous areas is the “leading edge” of the metal panels wherein the workers are typically concentrated and working to lay insulation and affix the metal panels to the purlins. Existing methods for protecting workers from falls are either overly costly or present practical problems in use.  
           [0007]    U.S. Pat. No. 6,003,282 issued to Alderman et al. describes a moveable safety barrier with a handrail for use during the placement of metal roofing panels. Alderman describes a carriage having rollers that are mounted for rolling along the top of the purlins during construction of a metal panel roof structure. The carriage features a deck for workers to stand on while they work. The During operation, the insulation and support material are dispensed from the rolls between the leading edge of the metal roof and the framework of the carriage.  
           [0008]    Alderman&#39;s device, while useful, has a number of operational drawbacks. Support sheets and optional support plates that are placed between the leading edge and the framework of the carriage provide fall protection. This is expensive and time consuming. Further, in order to dispense insulation and support sheet material from the rolls and/or to operate the winch to relocate the carriage, workers will move over the gap created between the metal panels already placed and the deck of the carriage. This exposes the workers to a risk of falling. If the optional support plates are not in place when the workers are moving, or if the support plates are improperly placed, the worker might fall through the gap without sufficient fall protection.  
           [0009]    U.S. Pat. No. 6,216,416, issued to West al. describes a metal roof installation system having an installation assembly with a handrail that can be moved across the purlins of a rooftop understructure. The installation assembly includes a material handling assembly and a working deck that are secured together and mounted upon rollers for rolling lateral movement across the rooftop substructure. The working deck underlies the metal roof panels. Workers stand upon the working deck while securing metal roof panels to the roof. The material handling assembly includes a series of parallel rollers that are aligned with one another to permit items to be rolled from one end of the roof to a desired spot upon the rooftop.  
           [0010]    The West system is also useful. However, it also has a number of problems that prevent it from providing an optimal solution. The use of a working deck that is disposed beneath the metal roof panels is cumbersome in practice and may tend to become hung up with the insulation disposed below the roof members and even damage the insulation during movement of the installation assembly across the rooftop.  
           [0011]    Both the Alderman and West devices incorporate decks or platforms upon which workers may stand during construction of the roof. This is undesirable for several reasons. First, it materially increases the weight of the device and necessitates the use of a separate prime mover to translate the device across the rooftop. Both Alderman and West teach the use of a winch for movement of their platforms across the length of the rooftop. The requirement for a winch increases the cost of the rooftop safety system substantially. Even without the weight factor, it is, as a practical matter, difficult or impossible for workers to move a device such as the ones described in the Alderman and West across the roof. The workers must stand on the deck or platform in order to reach the handrail, and the fact that the workers are standing on the deck or platform, precludes movement.  
           [0012]    Also, prior art handrail systems typically use rollers that simply ride atop the purlins. During use, the rollers might become disengaged from the purlins. Further, there is no positive braking mechanism for these handrail systems. As a result, inadvertent movement of the handrail is possible, thereby allowing falls to occur.  
           [0013]    A solution to the problems of the prior art would be desirable.  
         SUMMARY OF THE INVENTION  
         [0014]    The present invention provides an improved safety device as well as improved methods for providing fall protection during the installation of roofing panels. In a currently preferred embodiment, a moveable safety handrail system includes a pair of safety rails that are supported in a generally horizontal orientation by a plurality of outrigger assemblies. The outrigger assemblies each include a support portion for support of the rail members and a rolling frame portion that engages the purlins of a rooftop structure in rolling contact. The exemplary handrail system described also features a braking system that prevents inadvertent movement of the handrail device upon the rooftop understructure.  
           [0015]    In operation, the handrail portion of the handrail device is positioned at or very proximate the leading edge of the metal roof panels, thereby providing security against falls. The support portions for the handrail device are advantageously placed on the side of the handrail opposite where a worker is working, thereby preventing a worker from tripping over support struts and the like.  
           [0016]    The invention also provides the advantages of simplicity in construction and operation. Because there is no platform affixed to the handrail device upon which workers are to stand, the handrail device is typically light enough to be moved manually, without the need for a winch or other prime mover.  
           [0017]    It is an object of the present invention to provide a safety handrail system that can be translated across the length of a rooftop under construction by workers manually without the need for a prime mover, such as a winch. It is also an object of the invention to provide a safety handrail system that is simple and inexpensive to construct.  
           [0018]    It is a further object of the invention to provide a safety handrail system having improved interengagement with the purlins of a rooftop understructure, and a self-braking mechanism to preclude inadvertent movement of the handrail device during use.  
           [0019]    It is yet another object of the invention to provide a safety handrail system wherein the handrail lies adjacent to, or very proximate to, the leading edge of the metal roof panels during construction, thereby eliminating the presence of a dangerous gap between the handrail and the leading edge.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    The advantages and further aspects of the invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawing and wherein:  
         [0021]    [0021]FIG. 1 is an isometric view of an exemplary movable safety handrail system constructed in accordance with the present invention.  
         [0022]    [0022]FIG. 2 is a close up isometric view of one of the roller portions of the safety handrail system shown in FIG. 1.  
         [0023]    [0023]FIG. 3 is a detail view showing a roller assembly and braking device.  
         [0024]    [0024]FIG. 4 is a side cross-sectional view illustrating engagement of the roller assemblies and brake device with purlins of the roof line.  
         [0025]    [0025]FIG. 5 is a further detail view showing, in cross-section, engagement of a braking plate with a purlin.  
         [0026]    [0026]FIG. 6 is a side cross-sectional view of an outrigger portion of the handrail system.  
         [0027]    [0027]FIG. 7 depicts an alternative engagement structure for a safety handrail system constructed to be supported upon T-shaped bar joists.  
         [0028]    [0028]FIG. 8 is a close up detail of portions of the system shown in FIG. 7.  
         [0029]    [0029]FIG. 9 is a front view detail of an exemplary braking mechanism used in the safety handrail system shown in FIGS. 7 and 8.  
         [0030]    [0030]FIG. 10 is a side view detail of the braking mechanism shown in FIG. 9. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]    Turning first to FIGS.  1 - 6  there is shown an exemplary movable safety handrail assembly  10  which, in FIG. 1, is shown to be installed upon the rooftop structure  12  of a building that is being constructed. The rooftop structure  12  includes a plurality of parallel, I-beam rafters  14  and a plurality of parallel purlins  16  that are disposed atop the rafters  14  at right angles thereto. The purlins  16  have a reverse S-shaped cross-section, which as may be seen best in FIGS. 4 and 5, includes a central web  16 A and upper and lower flanges  16 B,  16 C, respectively. As FIG. 1 shows, a layer of insulation  18  has been laid atop the purlins  16 , and a layer of corrugated metal panels  20  overlies the insulation  18 . The metal panels  22  are secured by connectors (not shown) to the purlins  16 . In FIG. 1, the insulation  18  and metal panels  20  extend only partway across the rooftop structure  12 , indicating that construction of the building roof is ongoing. Workers typically stand upon the metal panels  20  to insert connectors that secure the metal panels  20  to the purlins  16 . The metal panels  20  present a leading edge  22 , the location of which changes as additional metal panels  20  are affixed to the purlins  16 . As the general mechanics of placement for insulation and metal roofing materials are well understood, they will not be described further here.  
         [0032]    The handrail assembly  10  includes a pair of tubular safety rails  24 ,  26  that are disposed in a parallel, spaced relation to one another, one above the other, to provide protection from falls to workers. The rails  24 ,  26  are secured in moveable relation to the purlins  16  by a plurality of outrigger assemblies  28 . Three outrigger assemblies  28  are shown in FIG. 1. Each outrigger assembly  28  includes a rectangular, horizontal rolling frame portion  30  and a vertically disposed, triangular support portion  32 . The rolling frame portion  30  consists of a pair of roller assemblies  34  that are adjustably interconnected via lateral struts  36 . During use, the roller assemblies  34  reside atop adjacent purlins  16  as FIG. 1 illustrates. The roller assemblies  34  feature a carriage housing  38  that is made up of welded cross-members and retains an axle  40  about which roller  42  rotates. During use, the roller  42  rollingly engages the upper surface of the top flange  16 B of a purlin  16 , as best illustrated in FIGS. 3 and 4.  
         [0033]    A friction brake shoe  44 A is secured, preferably by bolting, to the end of the carriage housing  38  that is proximate the safety rails  24 ,  26 . A second friction brake shoe  44 B is secured to the opposite end of the carriage housing  38 . The friction brake shoes  44 A,  44 B have the same construction, which is best appreciated by reference to the exemplary brake shoe  44  shown in FIG. 5. The exemplary plate  44  is square or rectangular having a square or rectangular cut-out portion  46  at its center so that a downward-facing frictional engagement surface  46 A is formed proximate the upper end of the plate  44 , and an upward-facing frictional engagement surface  46 B is formed proximate the lower end of the plate  44 . There is a slot  48  located off-center within the lower side of the plate  44 . As FIG. 5 shows, the brake shoe  44  is slidingly engaged with a purlin  16  by disposing the upper flange  16 B of the purlin  16  within the cut-out portion  46 . Rolling movement of a roller assembly  34  is inhibited when either of the engagement surfaces  46 A or  46 B of the brake shoes  44 A or  44 B are brought into frictional engagement with the upper flange  16 B of the purlin  16 .  
         [0034]    The handrail assembly  10  is self-braking since the natural balance of the assembly  10  will bring the engagement surfaces  46 A and  46 B of the brake shoes  44 A,  44 B into frictional engagement with the purlins  16 . FIG. 6 shows that the pivot  40  of the roller  42  for an exemplary roller assembly  34  is approximately balanced (L 1 =L 2 ), however, the additional weight of the safety rails  24 ,  26  and the portions associated with them cause the engagement surface  46 A of the brake shoe  44 A to be brought into contact with the flange  16 B while the engagement surface  46 B is also brought into contact with the flange  16 B.  
         [0035]    The carriage housings  38  are adjustably secured to the cross-members  36  so that the distance between the carriage housings  38  can be easily varied to account for variations in spacing between purlins  16 . Referring now to FIG. 4, it can be seen that the cross-member  36  contains a plurality of apertures  50 . The carriage housings  38  may be secured to the cross-member  36  using a pin or another suitable securing member  52 , such as those shown in FIGS. 2 and 3. The securing member  52  is inserted through a selected aperture  50  and a corresponding aperture (not shown) in the carriage housing  38  to secure the carriage housing  38  at a selected location on the cross-member  36 . Because there are a plurality of apertures, the distance between the carriage housings  38  may be adjustably varied (as arrows  39  in FIG. 4 illustrate) to account for different purlin spacings.  
         [0036]    An alternative embodiment for a safety handrail system  10 ′ is depicted in FIGS.  7 - 10 . Construction of the alternative safety handrail system  10 ′ is identical to the safety handrail system  10  except where indicated otherwise. Like components between the two embodiments are provided with like reference numerals. With this embodiment, bar joists  16 ′ are used rather than the purlins  16  described earlier. As FIGS. 7 and 8 depict, the bar joists  16 ′ have a T-shaped cross-section wherein there is a large, upper rectangular portion  54  and a lower, downwardly-projecting portion  56 . The braking mechanism of the alternative handrail system  10 ′ is best shown in FIG. 8 as well as  9  and  10 . The brake shoes  44 ′ feature a cross-piece  58  that, during use, is positioned atop a bar joist  16 ′. Additionally, a pair of gripping flanges  60 ,  62  will reside proximate the lower side of the bar joist  16 ′. These portions of the brake shoes  44 ′ may be selectively brought into frictional engagement with the upper and lower sides of the bar joist  16 ′ in order to prevent rolling movement of the handrail system  10 ′ along the bar joists  16 ′ of a rooftop structure. It is noted that the handrail systems  10  and  10 ′ of the present invention are useful as OSHA-recognized handrail systems rather than as fall protection systems. In a currently preferred construction, the handrail systems  10 ,  10 ′ are suitable to prevent a fall by a 200 pound man.  
         [0037]    In operation, the handrail assembly  10  or  10 ′ is constructed upon the rooftop structure of a building to be roofed or decked. The assembly  10 ,  10 ′ is constructed so that the safety rails  24 ,  26  lie parallel with the rafters  14 , and the supporting outriggers  32  of the assembly  10 ,  10 ′ are rollingly engaged with adjacent purlins  16  or bar joists  16 ′. The purlins  16  and bar joists  16 ′ may be considered to be rooftop understructure members along which the handrail assembly  10  or  10 ′ is moved. The handrail assembly  10  or  10 ′ is positioned at or near the leading edge  22  of the metal panels  20 . As noted previously, the weight of the safety rails  24 ,  26  and proximate portions will cause the brake shoes  44 ,  44 ′ to frictionally engage the purlins  16  or bar joists  16 ′ and prevent the handrail assembly  10  or  10 ′ from inadvertently moving. When it is desired to move the handrail assembly  10  or  10 ′, this may be done by having workers lift up on the safety rails  24 ,  26  to tilt the assembly  10 ,  10 ′ upon its rollers  42  and thereby disengaging the brake shoes  44  or  44 ′ from frictional engagement with the purlins  16  or bar joists  16 ′. The handrail assembly  10  or  10 ′ may then be manually rolled along the purlins  16  or  16 ′ to the new desired location. It is intended that the handrail assembly  10 ,  10 ′ will be located near the leading edge  22  of the metal plates  20  during essentially the entire roofing operation so that the safety rails  24 ,  26  may prevent or lessen the chance of a worker falling from atop the metal plates  20 .  
         [0038]    The system of the present invention provides a number of advantages. The length of safety rail protection may be made to match the width of the building being roofed by adding or removing the number of outriggers  32  that are used and by cutting the safety rails  24 ,  26  to size. Alternatively, one may have a plurality of modular rails that are located adjacent to one another and operated in tandem. Additionally, the assemblies  10 ,  10 ′ are adjustable to allow them to be installed on rooftops having varied purlin spacing. Further, the system is relatively inexpensive and easy to construct.  
         [0039]    Those of skill in the art will recognize that many modifications and changes may be made to the teachings herein while still remaining within the spirit and scope of the present invention.