Abstract:
A movable safety barrier system includes a flexible barrier member having a barrier member length with first and second ends, and a width. The barrier member can have a construction that is flexible in both directions along the length and width of the barrier member. First and second end supports are provided which are capable of supporting respective first and second ends of the length of the barrier member when the barrier member is extended between the end supports. The end supports can allow the extended barrier member to move in a direction transverse to the width of the barrier member when desired.

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 10/983,332, filed Nov. 5, 2004, now U.S. Pat. No. 7,665,576, which claims the benefit of U.S. Provisional Application No. 60/517,659, filed Nov. 6, 2003. The entire teachings of the above applications are incorporated herein by reference. 
    
    
     BACKGROUND 
     Workers on elevated construction projects, such as roofs, should have protection from falling, for example, while installing roof panels, insulation, fastenings, or other component parts of the roofing system. These workers are at risk of falling in the region extending in front of the installed roof panels. When insulation is spread over structural members ahead of the workers&#39; position, and ahead of the installed roof panels, the layer of insulation can give workers a false sense of security, since the insulation covers the structural members. However, the insulation is not strong enough to prevent a worker from falling through the insulation. One method of providing protection for workers against such falls is to apply netting over the entire roof structure, which is then covered by the insulation and roof panels. This method is not only expensive but the installation of the netting can also be dangerous. Another method of providing protection against falls is to secure safety lines to the workers. This method becomes unwieldy when multiple workers are moving back and forth over the roof, and often the workers end up disconnecting the lines. 
     SUMMARY 
     The present invention provides a movable safety barrier system which can be extended over structural members on elevated projects along the leading edge of construction, and can be advanced as the work progresses. 
     The barrier system can include a flexible barrier member having a barrier member length with first and second ends, and a width. The barrier member can have a construction that is flexible in both directions along the length and width of the barrier member. First and second end supports are provided which are capable of supporting respective first and second ends of the length of the barrier member when the barrier member is extended between the end supports. The end supports can allow the extended barrier member to move in a direction transverse to the width of the barrier member when desired. 
     In particular embodiments, the flexible barrier member can be extended across support members of a structure. The flexible barrier member can be made of netting material which can be a slippery plastic mesh-type material. The width of the flexible barrier member has a leading edge which can be reinforced to allow the barrier member to slide more evenly across the support members of the structure. The leading edge can be reinforced with a thin plastic member. The flexible barrier member can extend from at least one end from a roll. When at least one end of the flexible barrier member extends from a roll, the roll can be connected to a windup/unwind mechanism that is capable of locking in selected positions for selecting the tension of the barrier member. 
     First and second movable carriages can be employed for maintaining a fixed distance between the first and second ends of the length of the flexible barrier member when extended. The first and second carriages can move along selected support members of the structure. Each carriage can include a roller system for engaging and traveling along at least one selected support member of the structure. The roller system can include a series of side rollers and top rollers. Selected rollers are adjustable for adjusting to different sizes and spacings of the support members of the structure. The roller system can include at least one roller assembly for capturing and traveling along a selected support member of the structure. The at least one roller assembly can include opposed side rollers, and top rollers. The position of the at least one roller assembly can be adjustable relative to the carriage. 
     In one embodiment, first and second cables can be included to which the first and second ends of the length of the flexible barrier member are slidably secured, respectively. The barrier member is capable of sliding along the first and second cables in the direction transverse to the width of the barrier member. The first and second cables are retained by the carriages in the general region of the barrier member for maintaining the fixed distance between the first and second ends of the length of the barrier member when extended. 
     In another embodiment, the first and second ends of the length of the barrier member can be fixed to the first and second carriages, respectively. Each carriage can be generally triangular in shape. The flexible barrier member can extend over two sides of the triangle. The two sides can have recessed top surfaces to allow the barrier member to extend closer to the supports of the structure. 
     The present invention also provides a movable safety barrier system including a flexible barrier member having a barrier member length with first and second ends, and a width. The barrier member can extend from at least one end, from a roll. First and second end supports are provided which are capable of supporting respective first and second ends of the length of the barrier member when the barrier member is extended between the end supports. The end supports can allow the extended barrier member to move in a direction transverse to the width of the barrier member when desired. A windup/unwind mechanism can be connected to the roll and is capable of locking in selected positions for selecting the tension of the barrier member. 
     The present invention further provides a method of providing protection against falls with a movable safety barrier system when installing construction components over support members of a structure. A flexible barrier member can be positioned over the support members of the structure. The flexible barrier member has a barrier member length with first and second ends, and a width. The barrier member can have a construction that is flexible in both directions along the length and width of the barrier member. The width of the barrier member can be extended forward of a leading edge of construction. Respective first and second ends of the length of the barrier member can be supported while the barrier member is extended between first and second end supports. The end supports can allow the extended barrier member to move in a direction transverse to the width of the barrier member when desired. The construction components can be positioned over the support members of the structure with portions extending over part of the barrier member. The position of the barrier member can be moved forward by an amount that allows additional construction components to be positioned over the support members of the structure with portions extending over a part of the barrier member, while the width of the barrier member still extends forward of the construction components. 
     Embodiments of the movable safety barrier system can be easily and quickly set up and placed into position on a construction project, and can be quickly dismantled for reuse, thereby being economical. Once in place, the safety barrier system can be easily moved by the workers as the construction progresses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of particular embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
         FIG. 1  is a schematic drawing of a worker securing a roof panel in place with a barrier member of an embodiment of a movable safety barrier system in the present invention being in position under the leading edge of insulation and roofing. 
         FIG. 2  is a schematic drawing of the worker advancing the barrier member forward to a new position. 
         FIG. 3  is a schematic drawing of the worker placing a roof panel over insulation covering the new position of the barrier member. 
         FIG. 4  is a schematic drawing of the worker securing the new roof panel in place. 
         FIG. 5  is a schematic drawing of the worker again advancing the barrier member forward to a new position. 
         FIG. 6  is a schematic drawing of the worker placing insulation over the barrier member in its new position. 
         FIG. 7  is a perspective view of a roof being installed on a building with the movable safety barrier system in position at the leading edge of construction. 
         FIG. 8  is a top view of a roof being installed on a building with the movable safety barrier system in position at the leading edge of construction. 
         FIG. 9  is a side schematic view of the movable safety barrier system showing an embodiment of a cable arrangement. 
         FIG. 10  is a top view of one end of the movable safety barrier system showing a portion of a movable carriage and the end of the barrier member slidably secured to a cable. 
         FIG. 11  is a perspective view of a roller assembly of a movable carriage. 
         FIG. 12  is a perspective leading end view of a portion of the movable carriage showing an outboard top roller and a cable retention roller assembly. 
         FIG. 13  is a leading end view of the carriage traveling on roof beams, with an end of the barrier member extending from a roll. 
         FIG. 14  is a perspective view of one configuration for joining metal roof beams together. 
         FIG. 15  is a side view of the leading edge of an embodiment of the barrier member. 
         FIG. 16  is a perspective view of a roof being installed on a building with another embodiment of the present invention movable safety barrier system, in position at the leading edge of construction. 
         FIG. 17  is a top perspective view of a portion of one end of the embodiment of the movable safety barrier system of  FIG. 16  showing the barrier member secured to a movable carriage traveling on roof beams. 
         FIG. 18  is a top perspective view of the carriage of  FIG. 17  traveling on roof beams, with the barrier member omitted. 
         FIG. 19  is a leading end view of the carriage of  FIG. 17  traveling on roof beams, with an end of the barrier member extending from a roll fixed to the carriage. 
         FIG. 20  is a perspective view of one roller assembly on the trailing end of the carriage of  FIG. 17 . 
         FIG. 21  is a perspective view of another roller assembly on the trailing end of the carriage of  FIG. 17 . 
         FIG. 22  is a top perspective view of a portion of the carriage of  FIG. 17  showing an optional roller assembly. 
         FIG. 23  is an end schematic view of a roof with the movable carriages of the movable safety barrier system of  FIG. 16  being positioned on one half of the roof. 
         FIG. 24  is an end schematic view of a roof with the movable carriages of the movable safety barrier system of  FIG. 16  being positioned on opposite sides of the roof. 
         FIG. 25  is a schematic drawing of the safety barrier system of  FIG. 16  showing the safety barrier member extending from rolls of two carriages and including extension segments. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , movable safety barrier system  10  is an embodiment in the present invention which can be extended over elevated structures undergoing construction for catching and preventing a worker  20  from falling to the ground. In the application shown in  FIG. 1 , the elevated structure is the roof  15  on a building  24 , but it is understood that the elevated structure can be other structures, for example, elevated platforms, elevated roads, bridges, etc. In the example shown in  FIG. 1 , a flexible safety barrier sheet member  12  of the barrier system  10  extends over the roof support members or beams  14  of the building  24  along the leading edge of construction. In this example, the roof  15  includes a layer of insulation  18  and a series of roof panels  16  which are secured to the support beams  14 . The barrier member  12  extends under the leading edge of the insulation  18  and roof panels  16 . The worker  20  is shown securing a row of roof panels  16  and insulation  18  to the support beams  14  with fasteners  22 . Since the barrier member  12  is incrementally moved forward, the fasteners  22  are inserted at a location short of the barrier member  12  so as not to fasten the barrier member  12  to the support beam  14 . The barrier member  12  extends under a region covered solely by the insulation  18  to a position ahead of the insulation  18 . As a result, if the worker  20  happens to step through or beyond this region of insulation  18 , the barrier member  12  will catch the worker  20  and prevent the worker  20  from falling. 
     Referring to  FIG. 2 , as work progresses, the worker  20  then advances the position of the barrier member  12  so that the trailing edge at position “A” is moved, for example, by a pole  26 , to the edge of the insulation  18  at position “B”, and the leading edge at position “C” is moved forward to the new position “C”. This slides the barrier member  12  forward under the insulation  18  and positions the barrier member  12  in the proper location for continued installation of insulation  18  and roof panels  16 . The pole  26  can have structures at the distal end for gripping or catching the barrier member  12 , such as a hook or other suitable gripping protrusions. In addition, the pole  26  can have a marker  26   a  located at a position on the pole  26  corresponding to the distance that the barrier member  12  should be advanced relative to the roof panels  16 , to act as a guide for the worker  20 . 
     Referring to  FIG. 3 , another row of insulation  18  and roof panels  16  are placed over the barrier member  12  and the support beams  14 . As seen, the trailing edge of the barrier member  12  has moved from the former position “A” to the former position “B”, now becoming the new position “A”. The leading edge of the barrier member  12  has moved to a new position “C” ahead of the insulation  18  and roof panels  16  so as to provide protection for the worker  20  against falling. Referring to  FIG. 4 , the worker  20  then fastens the new roof panels  16  and insulation  18  to the support beams  14  just short of the barrier member  12 . 
     Referring to  FIG. 5 , the worker  20  again advances the barrier member  12  forward, which moves the trailing edge of the barrier member  12  to a new position “A” near the edge of the insulation  18  and roof panel  16 . Almost all of the width “W” of the barrier member  12  extends forward relative to the edge of the construction. Referring to  FIG. 6 , the worker  20  then places another row of insulation  18  in position, which extends over a portion of the barrier member  12 , and the process continues. Once the roof  15  is near completion, the safety barrier system can be removed from the roof  15  for reuse on another project. 
     In the building  24  depicted in  FIGS. 7 and 8 , the support beams  14  typically extend across the tops of a series of main frame members  32 . The building  24  is covered with corrugated siding  25   a  and the eaves on the sides  23  include closure pieces  25   b  which are shaped to mate with and seal any corrugations in the roof panels  16 . The length of the barrier member  12  of the movable safety barrier system  10  can be extended across substantially the width of the roof  15  of the building  24  over the peak with the width “W” extending forward from the leading edge of the construction to provide protection against falls for the workers  20 . The ends  28  of the barrier member  12  can be positioned near the sides  23  of building  24 . The ends  28  are slidably secured to a pair of cables  34  ( FIGS. 8-10 ) which in turn are secured to opposite sides  23  of the building  24 . Referring to  FIG. 9 , each cable  34  can be secured at an anchor point  38   a  on one end wall  21  and extend around a pulley assembly  38   b  on the opposite end wall  21  before extending down to a winch assembly  19 . The winch assembly  19  allows tightening of the cable  34 . For long buildings  24 , the cables  34  can be extended only along part of the length of the building at one time, and if the building  24  is wide, some cables  34  can be positioned at inward locations. The distance between the ends  28  of the barrier member  12  can be maintained at a fixed distance by two opposed or parallel carriages  30  which travel on support beams  14  located near the cables  34  ( FIGS. 10-13 ). 
     Each carriage  30  can have a cable retaining roller assembly  66  which is mounted to a carriage arm  60  of the carriage  30  by a bracket  68 , and which engages a cable  34  with a grooved wheel  66   a  such as a pulley, to prevent lateral movement of the cable  34  inwardly in the direction of arrow  69  ( FIG. 12 ). This also keeps the ends  28  of the barrier member  12  generally parallel to each other. The carriages  30  can be connected to the barrier member  12  by a connector  36  ( FIGS. 8 and 10 ). Each carriage  30  also includes a roller system having a roller assembly  50  mounted to the carriage arm  60  for capturing and rolling along one support beam  14 , and an outboard roller  62  extending from an end of the carriage arm  60  for engaging and rolling along the top of another support beam  14 . The roller assembly  50  can have a cross piece  50   b  with two fixed lateral side rollers  52  spaced apart on one side and one adjustable lateral side roller  54  intermediately spaced on the opposite side for laterally engaging and capturing opposite sides of a support beam  14  in a rolling fashion, and two top rollers  56  spaced apart for engaging and riding on the top of the support beam  14  in a rolling fashion ( FIGS. 10 ,  11  and  13 ). The roller assembly  50  is adjustably mounted to the carriage arm  60  by an adjustment sleeve  50   a  having a series of locking cams  64  ( FIG. 11 ). The carriage arm  60  can be formed of square tubing, as shown. Rollers  52  and  56  can be positioned on opposite sides of carriage arm  60  by cross piece  50   b . Although  FIGS. 2 and 5  depicted the barrier member  12  as being advanced by a pole  26 , alternatively, carriages  30  can be powered by motors, and be remotely controlled for advancing the barrier member  12 . 
     The position of the roller assembly  50  can be adjusted along the carriage arm  60  to adjust for varying distances between support beams  14  from one building  24  or structure to the next. Loosening the locking cams  64  on the adjustment sleeve  50   a  allows the roller assembly  50  to be slid along the carriage arm  60 , and tightening the locking cams  64  locks the roller assembly  50  in the desired position. The adjustment mechanism  58  for the adjustable lateral roller  54  provides adjustment towards and away from rollers  52  which allows the roller assembly  50  to be adjusted to accommodate support beams  14  of varying widths. When properly adjusted, the roller assembly  50  can move along a support beam  14  without significant twisting. 
     By having the outboard roller  62  of carriage  30  roll on the top of the support beam  14 , the carriage  30  can travel over the support beams  14  without having to extend around or ride on the sides  23  of the building  24 . This allows the siding  25   a  and closure pieces  25   b  to be installed before the roof panels  16  on the roof  15 , without risk of damage by any lateral rollers riding on the sides  23 . In the figures, the support members or beams  14  are shown as metal joists or purlins, but can be a variety of types of support beams such as I-beams, trusses, wood beams, etc. 
     One or both of the ends  28  of barrier member  12  can extend from rolls  40  ( FIGS. 10 and 13 ). The rolls  40  are slidably mounted to the cables  34  by connecting members  44  extending from the ends of the rolls  40  and slide members  46 . The slide members  46  can be pulleys. The connectors  36  extending between the carriage arms  60  and the connecting members  44  connect the carriages  30  to the barrier member  12 . The connectors  36  can be flexible, for example, being made from a chain or a cable, or can be rigid. The carriages  30  can also be pushed for advancing the barrier member  12  forward. 
     A windup/unwind mechanism  42  can be connected to the rolls  40  for winding or unwinding the length of the barrier member  12 , as well as for tightening the length of the barrier member  12  to the desired tension. The windup/unwind mechanism  42  can be a hand-operated device, such as a ratchet, or can be motorized. In some embodiments, the barrier member  12  can be extended from both rolls  40  on two sides and secured together. In other embodiments the barrier member  12  can be extended only from one roll  40  and secured to the opposite roll  40  or other suitable structure. As seen in  FIG. 13 , the barrier member  12  can extend over the top of the roll  40  so that if a worker  20  falls into or on top of the barrier member  12 , the resultant tension is better resisted by the carriages  30 . 
     Referring to  FIG. 14 , the support beams  14 , when metal purlins or joists, can be formed of overlapping lengths, for example,  14   a  and  14   b , which are overlapped at a region  13 . The length  14   a  can be overlapped over length  14   b  so that there is a step down, moving in the direction of construction. With such an overlap configuration, the barrier member  12  can be moved in the direction of construction without catching or getting hung up at region  13 . If the lengths  14   a  and  14   b  are overlapped the opposite way, stepping up in the direction of construction, the overlapped region  13  can be treated, for example, with a piece of adhesive tape, to provide smooth sliding of the barrier member  12  over the step up. 
     Referring to  FIG. 15 , the barrier member  12  can be formed of netting material, such as a slippery plastic mesh which allows wind to easily pass through, to prevent billowing. This plastic mesh can be reinforced with a reinforcing member such as a thin plastic strip  11  to promote smoother or more even sliding of the leading edge  12   b  over the support beams  14 . This can reduce the number of push points needed for advancing the barrier member  12 . The reinforcing plastic strip  11  can be captured by folding over a portion  12   a  of the barrier member  12  material and stitching or sealing in place. The plastic strip  11  can be formed of suitable materials such as nylon, delrin, polytetrafluorethylene (PTFE), etc. Alternatively, the leading edge  12   b  can be reinforced integrally during the manufacturing of the barrier member  12 . The trailing edge of the barrier member  12  can also be reinforced if desired. The barrier member  12  is typically flexible in both directions along the length and the width. Runners extending across the width “W” in the same direction and spacing as the support beams  14  are not required for promoting sliding on the support beams  14 . However, if desired, stiffeners can be added across the width “W” of the barrier member  12 . Such stiffeners can be flexible. In some applications, the width “W” of the barrier member  12  can be seven feet, such as when the roof panels  16  are three feet wide, the insulation is six feet wide, and where the barrier member  12  is meant to be positioned to be about one foot ahead of the insulation  18  without leaving a void between the roof panels  16  and the barrier member  12 . It is understood that both the width “W” and the length of the barrier member  12  can vary depending upon the application at hand. 
     Although the barrier member  12  has been described to be made of a plastic mesh-type netting, it is understood that the barrier member  12  can be formed of other suitable materials such as maritime-type netting, woven and unwoven textiles, fabric sheets, plastic, laminates or composite sheets, tarp-type sheets, metallic screen materials, etc. For barrier members  12  of generally solid sheet construction, openings can be provided to allow the passage of wind. The barrier member  12  is typically formed of material that can satisfy OSHA regulations, for example, 400 lbs. being dropped into the barrier member  12 . The material is also typically thin to allow the barrier member  12  to be rolled up on roll  40  without taking up a lot of space and to allow the barrier member  12  to slide easily when sandwiched between the roof panels  16 , insulation  18  and support beams  14 . In some embodiments, each roll  40  can hold about twenty to thirty feet of barrier member  12 . Other embodiments can contain lesser or greater amounts. A thin material also allows the barrier member  12  to be light weight and carried easily by workers  20 . 
     Referring to  FIGS. 16-19 , movable safety barrier system  70  is another embodiment in the present invention which differs form barrier system  10  in that the barrier system  70  includes two opposed or parallel carriages  72  having a construction where the cables  34  can be omitted and the ends  28  of the barrier member  12  can be mounted to the carriages  72  instead of to the cables  34 . Referring to  FIGS. 17-19 , a roll  40  from which the barrier member  12  is extended, can be mounted to a carriage arm  76  of a carriage  72  by brackets  78 . In the embodiment shown, carriage  72  has a generally triangular shape with carriage arm  76  being connected to carriage arms  74  and  79 . Carriage arm  76  is positioned to be parallel to the support beams  14  and sides  23  of the building  24 . The carriage arm  74  can be perpendicular to carriage arm  76  and is on the leading edge end of the carriage  72 . The carriage arm  74  can have two roller assemblies  50  mounted along the length which are similar to those in safety barrier system  10  for capturing and riding or rolling along separate support beams  14 . The roller assemblies  50  can resist twisting forces on the carriage  72 . The roller assemblies  50  are slidably adjustable relative to carriage arm  74  to adjust for varying positions and distances between the support beams  14 . The outboard top roller  62  can have an adjustable stem  62   a  extending from the end of carriage arm  74  for further adjustment purposes. A locking knob  62   b  can be included for locking the stem  62  in the desired position. Carriage arms  76  and  79  are on the trailing end of the carriage  72  with arm  79  forming the hypotenuse of the triangle. 
     As can be seen in  FIG. 17 , the barrier member  12  can extend over carriage arms  76  and  79 . In order to allow the barrier member  12  to extend across the carriage  72  and be as close as possible to the support members  14 , carriage arm  76  has a low profile or recessed distal portion  76   b  which steps down from a proximal portion  76   a , and carriage arm  79  is positioned in a low profile or recessed manner by connecting brackets  84   a  and  84   b . The low profile of carriage arms  76  and  79  is also desirable because the insulation  18  and roof panels  16  can extend over a portion of these carriage arms  76  and  79 , and a low profile brings these portions of carriage arms  76  and  79  close to the level of the support beams  14  and allows the carriage arms  76  and  79  to slide easily out from under the insulation  18  and roof panels  16 . The roll  40  can be mounted to the recessed distal portion  76   b  of the carriage arm  76 , as seen in  FIG. 19 . While carriage arms  74  and  76  can be made of square tubing as shown, carriage arm  79  can be a thin bar or rod to aid in providing the low or recessed profile. Alternatively, selected carriage arms can be made of round tubing, as well as angle, channel or bar stock, etc. Typically, the structural components of both carriages  30  and  72  are made of aluminum for purposes of light weight, but can be made of any suitable material. 
     The carriage arm  79  can include roller assemblies  80  and  82  for rollably engaging the sides of separate support beams  14  and further resisting lateral twisting of carriage  72 . Referring to  FIG. 20 , roller assembly  80  can have a lateral side roller  98  which is mounted to carriage arm  79  by bracket  92  and clamping fingers  96 . Roller  98  can be mounted to extend adjacent to and below carriage arm  79 . The carriage arm  79  can have steps  94  formed on opposite edges so that the bracket  92  and clamping fingers  96  can be mounted to the carriage arm  79  in a low profile manner. The position of the roller assembly  80  can be adjusted relative to the carriage arm  79  to adjust for different spacings and sizes of the support beams  14 . 
     Referring to  FIG. 21 , roller assembly  82  can have a lateral side roller  100  which is mounted to carriage arm  79  by bracket  104  and clamping fingers  96 . Roller  100  can be mounted below carriage arm  79 . Adjustment knobs  102  can be used to loosen and tighten the clamping fingers  96  on the steps  94  for providing adjustment of the position of roller assembly  82  relative to carriage arm  79  to allow for different spacings and sizes of the support beams  14 . The adjustment knobs  102  can also be employed with roller assembly  80 . The use of roller assemblies  80  and  82  can depend upon the type and configuration of the support beams  14 . Some configurations of the support beams  14  may allow more than one roller assembly  80  or more than one roller assembly  82 , in a variety of combinations. In addition, the roller assemblies  80  and  82  can be of other suitable configuration than those shown, and can have vertical adjustment capabilities and vertical rollers. As with carriages  30 , carriages  72  can be powered by motors and remotely operated. 
     Referring to  FIGS. 18 and 22 , the carriage  72  can optionally include an auxiliary outboard roller assembly  84  having a top outboard roller  90  which rides over the top of the same support beam  14  as outboard roller  62 , but is spaced apart from roller  62 . The auxiliary roller assembly  84  can provide further stability for the carriage  72  and further support the trailing end of the carriage  72 . The auxiliary roller assembly  84  can be secured to the carriage arm  76 , for example, at the proximal portion  76   a , where a protrusion  86   a  locks within a mating socket  86   b . The auxiliary roller assembly  84  has a longitudinal spacing arm  86  and a cross arm  88  which positions the outboard roller  90  spaced apart from, and generally in line with roller  62 . The outboard roller  90  can have an adjustment stem  90   a  for adjusting the position of the outboard roller  90  and a locking knob  90   b  for locking the stem  90   a  in the desired position. 
       FIG. 23  depicts the use of movable safety barrier system  70  on one side of the roof  15  or peak of a building  24 . This can be a construction style decision, or based on the length of the barrier member  12 . The construction of the carriages  72  allows the barrier member  12  to be positioned near the sides  23  of the building  24  without engaging surfaces of the sides  23 , so that the siding  25   a  and closure pieces  25   b  do not become damaged. 
       FIG. 24 , depicts the movable safety barrier system  70  being positioned across the width of the roof  15  such as seen in  FIG. 16 . In cases where the width across the roof  15  is greater than the length of the barrier member  12  stored on the carriages  72 , one or more extension segments  107  can be used for increasing the length of the barrier member  12  ( FIG. 25 ). The segments  107  can be connected by a series of fasteners such as rings  106  to each other, and the portions of the barrier member  12  which extend from the rolls  40 . The rings  106  can have spring loaded entrance portions. In example, if the rolls  40  each hold thirty feet of barrier member material, the total length of the barrier member  12  can be sixty feet plus the length of the extension segments  107  used. 
     While this invention has been particularly shown and described with references to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. 
     For example, although the present invention has been mostly described for use when installing insulation and corrugated roof panels on a shallow sloped roof, it is understood that the present invention can be used on a variety of elevated structures for the installation of a number of different components. The surfaces can be flat as well as sloped. In addition, carriages  30  and  70  can have other shapes and configurations than those shown, depending upon the situation at hand. A variety of different roller systems and roller assemblies are possible. Furthermore, various features of the embodiments discussed above can be omitted or combined.