Patent Publication Number: US-8978820-B2

Title: Traveling fall protection system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims benefit of priority to U.S. Application Ser. No. 60/788,910 filed on Apr. 4, 2006, the entirety of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD OF INVENTION 
     The invention generally relates to personal fall protection devices and, more particularly, to a fall protection assembly which permits an individual to move in multiple dimensions on a structure while providing fall arrest safety features and protecting against swing falls. 
     BRIEF DESCRIPTION OF RELATED ART 
     Personal fall protection assemblies are commonly used by individuals exposed to heights. For example, in construction or maintenance of buildings, bridges, towers, and the like, workers often perform tasks at higher elevations at or near an edge of a structure from which a fall could result in injury. Fall protection assemblies employed in such situations conventionally include a safety harness worn by the individual worker which is connected to a safety cable or line that is anchored, in one of various ways, to the structure upon which the individual is working. These assemblies are designed to reliably arrest the descent of the work if a fall should occur. 
     However, many of these conventional fall protection assemblies do not offer the worker sufficient freedom to move about a structure and perform their work effectively. Further, there are often considerable difficulties in achieving the necessary mechanical strength to arrest the fall of an adult worker. This is because such safety assemblies are temporary in nature and thus must be light enough to raise, maneuver, and erect upon the structure and yet strong enough to provide sufficient fall arrest capabilities. 
     Horizontal lifeline arrangements are often used to provide fall protection for individuals at these elevated positions on a structure. In these arrangements, a horizontal safety line is mounted upon the structure by way of mounting stanchions or other vertical supports. The horizontal line traverses the structure near an edge and is disposed typically above the height of a an average worker that that the worker can freely walk on the structure beneath the horizontal line. The individual worker is tethered to the horizontal line by a safety line extending from worker&#39;s harness. This horizontal lifeline arrangement allows the worker to move along the horizontal line while limiting movement in the vertical direction, e.g. to prevent falling. That is, should the worker fall when connected to such horizontal lifeline arrangement, the worker&#39;s descent will be arrested by the interaction of the horizontal line and the safety line tethering the worker. 
     While this horizontal lifeline arrangement ceases a vertical drop, the worker is still nonetheless exposed to dangers associated with a swing fall. This occurs when a worker falls from a position other than directly beneath the horizontal lifeline and results in a pendulum-like swing of the fallen worker exposing the worker to collision hazards with the building structure. For example, a worker tethered to a horizontal lifeline may maneuver outward from the horizontal lifeline on a cross-beam, etc., in a direction generally transverse to the horizontal line. A fall from such position would result in downward and horizontal acceleration forces sending the worker into a dangerous swing beneath the horizontal line. 
     Accordingly, a fall protection assembly is desired which has the necessary mechanical strength to arrest the fall of a worker, limits the vertical direction the worker may travel in the case of a fall, reduces occurrence of swing falls, and still provides the worker with sufficient capability for movement along and about a structure in order to perform required work, maintenance, etc. 
     BRIEF SUMMARY OF THE INVENTION 
     The above discussed and other problems and deficiencies of the prior art are overcome or alleviated by the invention, which provides a novel and nonobvious fall protection system. 
     The invention provides a fall protection system for an individual maneuvering about a structure, the structure having structure sections disposed equidistant from each other and at least one transverse section extending between the equidistant sections. The system generally comprises a first cable support disposed on one of the equidistant structure sections, a second cable support disposed on another of the equidistant structure sections, a transverse cable support extending between the first and second cable supports, a rigid member operably associated with the transverse cable support and configured to span the distance between the first and second cable supports, and a personal fall arrest assembly attached to and movable relative to the transverse cable support. The transverse cable support and the rigid member are further configured to move relative to the equidistant and transverse structure sections and relative to the first and second cable supports. 
     The invention further provides a fall protection system for an individual maneuvering about a structure, the structure having structure sections disposed opposite from each other and at least one transverse section extending between the opposite structure sections. Here, the system comprises a first support element extending above a first of the opposite structure sections, a second support element extending above a second of the opposite structure sections, a third support element connected to and movably associated with the first and second support elements, the third support element extending between the first and second support elements, and a fall arrest assembly connected at one end in movable association with the third support element and connected at another end to the individual. The first, second, and third support elements comprise cables which are configured to resist horizontal and vertical forces associated with a fall of the individual from the structure. The third support member further comprises a rigid member for resisting horizontal forces associated with said fall. 
     The invention also provides a fall protection system for an individual on a structure where the system comprises a support point and a fall arrest assembly connected to the support point and connected to the individual. The support point is configured to move with the individual about the structure. The fall arrest assembly comprises one or more cables to support vertical loads and a rigid member to resist compression forces associated with said loads. 
     The above discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings wherein like elements are numbered alike in the several FIGURES: 
         FIG. 1  is a perspective view of a fall protection system in one embodiment of the invention; 
         FIG. 2  is another perspective view of the fall protection system of  FIG. 1  including an individual connected thereto; 
         FIG. 3  is an elevation view of a rigid member of the fall protection system; 
         FIG. 4  is a plan view of a fall protection system in another embodiment of the invention. 
         FIG. 5  includes testing data relative to the invention; and 
         FIGS. 6-10  are photos of the invention related to the testing of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 and 2  show a fall protection system  100  in one exemplary embodiment of the invention. The fall protection system  100  is shown being used by a worker  10  to maneuver about a structure  90 . The structure  90  may occupy an elevated position such as is common during construction, maintenance or similar activities with respect to buildings, bridges, walls, towers or like structures which require a worker  10  to perform work at an elevated distance above the ground. The fall protection system  100  may generally be employed anywhere fall protection is required by safety standards or other similar regulations to prevent or reduce serious injury to the worker  10  should they somehow slip or fall from the elevated position. 
       FIGS. 1 and 2  show the structure  90  as generally including two parallel structure section  92  and  92 ′. A transverse section  94  extends between the structure sections  92 ,  92 ′ and in this example is shown generally perpendicular to the structure sections  92 ,  92 ′ but may be disposed at an angle thereto, etc. The structure sections  92 ,  92 ′ generally represent adjacent parallel structure segments disposed on any structure (building, bridge, tower, etc.). The transverse section  94  generally represents any cross segment which may be disposed between the structure sections  92 ,  92 ′. 
     Structure sections  92 ,  92 ′ may be composed of rails, beams, I-beams, walls or the like, or any combination of these items relative to the particular building, bridge, wall, tower or like object which the structure  90  is associated with. It should be evident that other elements characterizing the shape, dimensions or configuration of structure sections  92 ,  92 ′ used in the context of the claimed invention are well known and need not be addressed further. 
     The structure sections  92 ,  92 ′ include fall protection traveler assembly  20  for providing fall protection to the worker  10  and for allowing movement of the worker  10  moving relative to the structure sections  92 ,  92 ′,  94 . The fall protection traveler assembly  20  is generally anchored to the structure  90  or some other non-movable object. This anchoring includes the use of a vertical element  24 , such as a stanchion or other suitable object, as shown in the embodiment of  FIGS. 1 and 2 . While there is a vertical element  24  proximate each end of the structure sections  92 ,  92 ′, it is possible to have any of a number of vertical elements  24  or anchoring points for the fall protection traveler assembly  20  along the structure sections  92 ,  92 ′. For example, an additional vertical element  24  may be disposed at mid-length along one or both of the structure sections  92 ,  92 ′. The vertical supports  24  may be mounted upon the structure sections  92 ,  92 ′ by way of welding, bolting, etc., or any combination of these. 
     The use of the vertical elements  24  to affix the fall protection traveler assembly  20  to the structure  90  is discussed herein by way of example only. The assembly  20  may generally be fixed to the structure  90  in any manner sufficient to provide adequate securement. For example, the fall protection traveler assembly  20  may be alternatively affixed directly to elements of the structure  90 , for example, directly to vertical beams of the structure  90 , etc. 
     As shown in  FIG. 1 , the fall protection traveler assembly  20  includes flexible support elements  22  which span at least a portion of each of the structure sections  92 ,  92 ′. Opposing ends of each of the support elements  22  are attached to the vertical elements  24 . Thus, in this exemplary embodiment, four vertical elements  24  are employed. The support elements  22  are maintained generally in a substantially taut condition between the vertical elements  24 . The flexible support elements  22  are attached to the vertical elements  24  by any desired suitable means such as bolting, tying, etc. The flexible support elements  22  may be steel wire, cable-like, or some similar element of sufficient mechanical strength to decelerate and arrest a fall of the worker  10 , as discussed further herein. The flexible support elements  22  may include tensioning or shock absorbing devices in order to decelerate the fall prior to full fall arrest and to generally absorb shock forces associated with fall arrest. The vertical elements  24  may be configured to suspend the flexible support elements  22  above the head of the worker  10  so that the worker  10  may move beneath the support elements  22  free from contact therewith. 
     The fall protection traveler assembly  20  further includes a rigid member  30  extending transversely between the flexible support elements  22 , as shown in  FIGS. 1 and 2 . The worker  10  is tethered to the rigid member  30  by a harness  80  worn on the person of the worker  10  and a line arrangement  60  extending between the harness  80  and the rigid member  30 . The rigid member  30  is particularly configured to move relative to the support elements  22 . Movement of the rigid member  30  may be achieved by mechanically or electrically assisted means, but it is preferred that the rigid member  30  be manually movable by the worker  10 , such as by pushing or pulling. 
     The fall protection traveler assembly  20  is sufficiently configured to support and secure the rigid member  30  as it is moved relative to the support elements  22 . For example, the flexible support elements  22  and vertical elements  24  sustain the weight of the rigid member  30  and also prevent the rigid member  30  from moving beyond the vertical element  24 . Additionally, the fall protection traveler assembly  20  is of sufficient mechanical strength to sustain the vertical force as a result of the fall of a worker  10  tethered to the rigid member  30 , as will be discussed in more detail herein. 
     The rigid member  30  is of sufficient length to extend between the support elements  22  and is constructed of a substantially stiff or inelastic material, such as steel, plastic, etc., that will stay rigid and generally resist bending as a result of compression forces created during a fall of the worker  10 , as will be discussed more in detail herein. The rigid member  30  may comprise any one of a tube, a pipe, a bar, a pole, a rail, a rod, a beam, an I-Beam or the like, and be of any shape or cross-sectional profile maintaining stiffness or inelasticity commensurate with the material of which it is composed. 
     In one example, the rigid member  30  comprises an elongated tube which is affixed at either of its ends to the flexible support elements  22  by pulley arrangements  50  which allow the rigid member  30  to move upon the elements  22 . This tubular rigid member  30  may further include a line (not shown) extending through an interior of the tube. Opposite ends of the line may be affixed to the pulley arrangements  50  such that the line further supports the rigid member (and a fallen worker) between the flexible support elements. 
     In another example, the rigid member  30  is not connected directly to the pulley arrangements  50 . Instead the rigid member  30  may simply extend over and essentially hang upon the line arrangement  60  which is connected at its ends to the pulley arrangements  50 . Here, the rigid member generally extends towards the ends of the line arrangement  60  and is supported in the vertical direction by the line arrangement  60 , but does not connect directly to the flexible support elements  22 . Instead, the two ends of the line are moveably connected to the support elements  22  at the pulley arrangements  50  such that the assembly of the line arrangement  60  and the rigid member  30  extends between the support elements  22  and may selectively move along the support elements  22 . 
     Where the distance between structure sections  92 ,  92 ′ is substantial, the rigid member  30  length would consequently be substantial and may provide some difficulty in transporting the rigid member  30  between work sites. As a result, it may be desirable for the rigid member  30  to be of a reasonably transportable length. While the rigid member  30  may be a single piece unit, it is also contemplated that the rigid member  30  may be of a sectional construction. In this manner, the rigid member  30  could be converted into a manageable length for transport between work sites and then converted into a fixed appropriate length for use with the structure  90  at the site. For example, the rigid member  20  may comprise a plurality of tubular sections which may be bolted together onsite to provide the rigid member  30  of sufficient length. 
     The line arrangement  60  which attaches the harness  80  of the worker  10  to the rigid member  30  and/or to the flexible support elements  22  comprises any suitable arrangement that allows sufficient movement of the worker  10  relative to the rigid member  30  and that is sufficient to sustain the vertical force in the case of a fall of the worker  10 . Such arrangement  60  may include a safety lifeline, a retractable lifeline, a lanyard, associated clips, snaphooks, d-rings and other attachment devices, or other mechanisms that are generally used to tether persons a safety line or similar device. 
     In one exemplary embodiment, the line arrangement  60  comprises two individual lines  62  which descend from opposite ends of the rigid member  30  and attach to a support member  40 . In another embodiment, the line arrangement  60  comprises one continuous line which is attached at its ends to the pulley arrangements  50  and which supports the rigid member  30 . The line arrangement  60  may further include a line extending through a hollow interior of the rigid member  30  to provide vertical support thereto. Beneath the line arrangement  60 , a harness line  42  descends from the support member  40  and attaches to the harness  80  of the worker  10 . The support member  40  may be fixed relative to the descending lines  62  of the line arrangement  60  or may be movable with respect thereto. 
     In one embodiment, the line arrangement  60  includes a single line  62  which traverses through the tubular rigid member  30  and then descends downward to the support member  40  which is movably attached to the line  62 . Here, the line  62  may be directly connected to the pulley arrangements  50  at the ends of the rigid member  30  or may alternatively be disposed freely therefrom. In this latter version, the rigid member  30  is connected to the pulley arrangements  50 . In the former version, the line  62  is a continuous loop which is connected to and runs from one pulley arrangement  50 , through the rigid tube support member  30 , to the opposite pulley arrangement  50 , and down to the support member  40 . The rigid member  30  essentially rides on the portion of the line  62  which extends through the member  30  between the pulley arrangements  50 . The support member  40  is movably connected to the line  62  by way of a ring, pulley arrangement, etc., or by any means suitable to allow movement of the support member  40  relative to the line  62  and to provide sufficient strength to endure forces associated with a fall of the worker  10 . 
     As shown in  FIG. 2 , in use the fall protection system  100  allows the worker  10  to move freely about the structure  90  in X, Y, and Z directions while remaining tethered to the fall protection traveler assembly  20 . That is, the worker  10  may easily maneuver about all portions of the structure sections  92 ,  92 ′ and the transverse section  94 . In  FIG. 2 , the worker  10  is shown at approximately mid-length of the transverse member  94 . Here, the support member  40  is generally disposed mid-length with the worker  10 . When the worker  10  walks in the Y direction toward either of the structure sections  92 ,  92 ′, the worker  10  trails the support member  40  due to the movable connection of the support member  40  upon the line  62 . When the worker walks on either of the structure sections  92 ,  92 ′ towards, for example, one of the vertical elements  24 , the worker  10  trails the rigid member  30  by way of the pulley arrangements  50  disposed at either end of the rigid member  30  which provide for movement of the rigid member  30  relative to the flexible support elements  22 . That is, as the worker moves in the X direction beneath the flexible supports  22 , the rigid member is pulled by the line arrangement  60 ,  62  attached to the worker  10  such that the rigid member  30  travels with the worker  10 . 
     In this way, the fall protection traveler system  20  allows the worker full freedom of movement in the X and Y directions. Additionally, the fall protection traveler system  20  allows the worker  10  to move freely in the Z direction to the extent of the length of the line arrangement  60 . For example, the worker  10  connected to the system  20  may freely move atop an elevated portion  96  of the structure sections  92 ,  92 ′. Similarly, if desired, the worker  10  could descend relative to the structure sections  92 ,  92 ′ and the transverse section  94 . Of course, the movement in the Z direction is limited by the length from the rigid member  30  provided by the line arrangement  30 . Advantageously, while moving in any of the X, Y, and Z directions the worker retains adequate fall protection from the traveler system  20 , as addressed in more detail below. 
       FIG. 3  shows an enlarged view of the rigid member  30 . Here, the pulley arrangement  50  is shown as being connected to the rigid member  30 . As shown in  FIGS. 1 and 2 , the pulley arrangement  50  is disposed proximate to each end of the rigid member  30 . The pulley arrangement  50  may be constructed as a separate part or may be formed integral to the rigid member  30 . The pulley arrangement  50  may include an extension  52  which connects the pulley arrangement  50  to the rigid member  30  and allows the rigid member  30  to hang below and unobstructed from the flexible supports  22 . It is contemplated that the pulley arrangement  50  may be connected in any manner that does not interfere with the movement of the rigid member  30  along the flexible supports  22 . 
     In another embodiment, the extension  52  is a extended portion of the line  62  which forms the line arrangement  60 . In this embodiment, the line extension  52  is connected to the pulley arrangement  50  and the rigid member  30  rides upon the line arrangement  60  as discussed hereinabove. 
     The pulley arrangement  50  is generally configured to support and/or to secure the rigid member  30  relative to the flexible supports  22  and to provide for the movability of the rigid member  30  and the line arrangement  60  relative thereto. Depending on the configuration of the fall protection traveler assembly  20 , the pulley arrangement  50  is chosen accordingly, to be movable relative to the fall protection traveler assembly  20 . A pulley arrangement  50  may include but is not limited to a roller, a wheel, a ball, a bearing, a clip, a pulley or the like, or any combination of the foregoing. 
     The rigid member  30  may optionally include a cable stay assembly  70 , as shown in  FIG. 3 , to provide additional buckling or bending resistance to the rigid member  30 . In this exemplary embodiment, one cable stay assembly  70  is disposed on each of opposing sides of the rigid member  30 . Each cable stay assembly  70  spans approximately the length of the rigid member  30  and includes a cable stay  72  and a spreader  74 . The cable stay  72  is attached by any suitable means at each of the opposing ends of the rigid member  30  proximate to the pulley arrangements. The cable stay  72  generally extends the length of the rigid member  30  and traverses atop the spreader  74 . 
     The cable stay  72  and the spreader  74  are configured to not interfere with movement of the rigid member  30  along the flexible supports  22  nor with the operation of line arrangement  60  beneath the rigid member  30 . As shown in  FIG. 3 , the cable stays  72  are connected to the rigid member  30  so as not to interfere with the pulley arrangement  50 . Additionally, the line arrangement  60  is shown hanging below and sufficiently away from the lower stay  72  and spreader  74  so that movement of the worker  10  along the is not obstructed by the cable stay assembly  70 . 
     If the worker  10  should fall from the structure  90  while connected to the line arrangement  60 , the lines  62  will exert a downward force at each opposite pulley arrangement  50 . This downward force will be translated to the flexible support elements  22  which will react downwardly. This downward force will tend to pull the flexible support elements  22  inward toward one another resulting in a compression force within the rigid member  30 . Any buckling that may tend to occur in reaction to this compression force will be countered and reduced or negated by the rigidity of the rigid member and/or by the tension forces in one or both of the cable stays  72  of the cable stay assembly  70 . 
     As discussed above, the fall protection traveler assembly  20  allows the worker  10  freedom of movement in the X, Y, and Z directions on the structure  90 . This is because the support member  40  is configured to move laterally in the X direction with the worker  10 , the entire rigid member  30  and line arrangement  60  moves along the flexible supports  22  with the worker  10  in the Y direction, and the line arrangement  60  has sufficient slack to allow the worker to move distances in the Z direction. 
     Further advantageously, at all points on the structure  90 , the worker  10  is provided with sufficient fall protection and, moreover, protection against dangerous swing falls. Such swing falls involve downward movement in the Z direction as well as lateral movement in the X and/or Y directions to result in a pendulum-like swing of the fallen worker  10  which can lead to a collision with the structure  90  or with equipment surrounding the structure, etc. Such swing falls occur when a worker moves laterally away from an overhead point of support. Falling from such a laterally distal position results in the dangerous swing discussed above. 
     The fall protection traveler assembly  20  of the invention practically negates swing falls or at least minimizes the swing involved in a fall of the worker  10 . This is because the assembly  20  maintains the point of support generally above the worker during movement of the worker in all of the X, Y, and Z directions. That is, the traveling nature of the rigid support  30  upon the flexible supports  22  and the traveling nature of the support member  40  upon the lines  62 , ensures that the point of support of the worker  10  is generally maintained above or at least proximate to the worker  10  despite any movements made upon the structure  90 . Whether the worker  10  falls from the parallel structure sections  92 ,  92 ′ or from the perpendicular transverse section  94 , the worker  10  will descend generally straight downward in the Z direction with little or no movement in the X and Y directions. As mentioned, this is because the worker  10  trails the fall protection traveler assembly  20  as the worker  10  moves about the sections  92 ,  92 ′,  94  of the structure  90  such that at all times the support member  40  remains proximate to the worker. Thus, a fall from any position entails only minimal or no movement in the X and Y direction and, resultantly, a minimal swing fall. 
     As mentioned above, in a preferred embodiment, the rigid member  30  comprises a hollow tubular member. The line  62  extends generally beneath the rigid member  30  and is connected at either end to the flexible support elements  22  at the pulley arrangements  50 . The line  62  then extends downward to support the support member  40 . The ends of the rigid member  30  may include a guide or pulley, etc., for fixing (movably or immovably) the line  62  thereto and/or for guiding the line  62  relative thereto In this arrangement, the rigid member  30  is supported vertically by, and generally rides upon the line  62 . A downward force on the support member  40 , e.g., from a fall, is translated through the line  62  and pulley arrangement  50  to the flexible support elements  22 . The rigid member  30  resists horizontal forces generated at its ends due to the downward force applied to the line  62 . That is, the weight of a fallen worker will pull downward on the line  62  thus creating a reaction point at either end of the rigid member  30  where the line  62  contacts and traverses the rigid member  30 . The horizontal force generated at these reaction points is transferred inwardly to the rigid member which resists the resulting compression. Advantageously, this fall protection traveler assembly  20  is highly mobile and portable and may be quickly and easily assembled on any structure where fall protection is desired. 
     Herein, the fall protection traveler assembly  20  is discussed as being disposed upon the parallel structure sections  92 ,  92 ′ and above the transverse section  94 . This disposition of the assembly  20  is, of course, provided only by way of non-limiting example. The sections  92 ,  92 ′,  94  may only represent a portion of the structure  90 . The structure  90  may include further sections which extend away from the sections  92 ,  92 ′,  94 , in which case the flexible supports  22  correspondingly extend along the structure  90  to provide for maneuverability and non-swing fall protection as generally discussed above. Also, the structure sections  92 ,  92 ′ are disclosed as being straight members disposed parallel to one another but may be any shape equidistant from one another. For example, the sections  92 ,  92 ′ may be similarly shaped arcs which are disposed equidistant from one another. Alternatively, the sections  92 ,  92 ′ may converge and/or diverge with respect to one another. The sections  92 ,  92 ′ may further incline or decline relative to horizontal and/or relative to one another. 
     The invention further contemplates alternate arrangements of movably connecting the rigid member  30  to the fall protection traveler assembly  20 . For example,  FIG. 4  shows a configuration where the structure  90  includes a rounded section  92 . Here, a single flexible support  22  traverses the rounded section  92  and is supported by a plurality of vertical elements  24  (not shown). An end A of the rigid member  30  is connected to the flexible support  22  by way of the pulley arrangement  50 , as discussed above. An opposite end B of the rigid member  30  is fixed on a transverse section  94  of the structure  90  in such a way as to enable rotational movement of the rigid member  30  about the end B. That is, in this exemplary embodiment, the rigid member  30  is able to pivot about the end B. In this way, the worker  10  may traverse the various sections  92  and  94  of the structure  90  freely while trailing the rigid member  30  and the line arrangement  92  behind in order to provide protection against falls and particularly against swing falls, as is generally discussed above with regard to  FIGS. 1-3 . 
     The invention thus provides an advantageous fall protection system which allows an individual tethered thereto to maneuver freely about a structure in all directions while still providing fall arrest protection to the individual and, particularly, protection against swing falls, at all positions of the individual on the structure, where the fall protection system possesses a very simple construction which may be easily moved and erected on a variety of structures. 
     While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.