Patent Application
20080041660
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.
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'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'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.
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.
Referring now to the drawings wherein like elements are numbered alike in the several FIGURES:
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
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
The fall protection traveler assembly 20 further includes a rigid member 30 extending transversely between the flexible support elements 22, as shown in
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 50 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 50 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
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.
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
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
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,
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.
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.
| Number | Date | Country | |
|---|---|---|---|
| 60788910 | Apr 2006 | US |
