Abstract:
A fall-arrest system for securing an individual to a construction site. The system and methods include a first post for insertion into a concrete column. A sleeve connects the first post to a second post that extends above the concrete. A cable is used to connect an individual to the second post, and thus secure them to the construction site. The sleeve prevents lateral movement at the connection of the two posts such that the second post does not rely on uncured portions of the column for support.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
       [0001]    This application claims priority from U.S. Provisional Patent Application 61/008,356 filed Dec. 20, 2007, herein incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The invention relates generally to the field of fall arrest systems and methods. 
         [0003]    One major concern in building multi-story structures is the safety of workers. In particular, the risk of falling becomes a concern. A challenge in providing a system for preventing workers from falling exists because the uppermost floor is being worked on without there being any structure above that level to which the workers can be tethered. Thus, it is necessary to tether the workers back to the current level being worked on or to a preceding level. 
         [0004]    However, in order for a worker to be able to be tethered to an existing level, that level must have sufficient structural integrity to support the worker (and the fall arrest apparatus). This presents a problem in modern concrete-based construction. It would be necessary to allow the concrete to cure (harden) prior to tethering a working to the concrete. In particular, this presents a problem for large vertical structures such as sky-scrapers, where an entire floor is likely to be “finished” prior to the concrete having cured sufficiently to support tethering a worker. Thus, it is necessary to delay construction until the concrete has cured sufficiently to support attachment of a fall-arrest system. 
       SUMMARY OF THE INVENTION 
       [0005]    One embodiment of the invention relates to a fall arrest system. The fall arrest system comprises a pipe and sleeve attached to a concrete structure to provide structurally sufficient tie off points without relying on the strength of the concrete. 
         [0006]    In one embodiment, the invention comprises a fall arrest system utilizing a concrete column. The system includes an upright support, the upright support having a plurality of posts and a plurality of sleeves. The plurality of posts are stacked within the concrete column, with one of the plurality of sleeves positioned at a junction between each post and another post. Each of the plurality of sleeves are substantially securing the junction against lateral movement. An upper-most post extends from the concrete column, the upper most post having a safety cable connected at an end distal to the concrete column. The cable is attachable to a user harness and the upright support is able to bear the load of a user attached to the cable in the event of a fall. 
         [0007]    In another embodiment, the invention relates to a method of securing an individual to a construction site, comprising disposing a first post in a column of substantially cured concrete. The first post is connected to a second post, which extends beyond the cured concrete, at a junction using a sleeve; the sleeve reinforcing the junction of the first post and second post against lateral movement. A cable is secured to the second post, the cable engagable with a user harness. 
         [0008]    In yet another embodiment, the invention relates to a fall-arrest safety device comprising of a plurality of upright supports. The upright supports comprise a sleeve and a post. Each upright support is connected to at least one other upright support via interaction of the sleeve of one upright support with the post of the other upright support, the connection secured against lateral movement. A user tie-off line is engagable with at least one upright support for securing a user to the upright support. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an illustration of a construction location utilizing the described system; 
           [0010]      FIG. 2  illustrates a cut-away view of a fall-arrest system having a sleeve internal to the upright supports; 
           [0011]      FIG. 3  illustrates a cut-away view of a fall-arrest system having a sleeve integral to the upright supports; 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0012]      FIG. 1  illustrates a portion of a construction location where a fall arrest system would be utilized. It should be appreciated that a plethora of methods of building a structure may be used, and the following illustration is not meant to be limiting but only to provide an example.  FIG. 1  depicts three stories of a construction site, a completed level&#39;s floor  11 , a current level&#39;s floor  12 , and the next level&#39;s floor  13 . The common sequence for construction of the illustrated structure is to place concrete into forms (not shown) on the first day of construction for the current level floor  12 . Next, the concrete for columns  16  and walls  18 , which will support the next level&#39;s floor  13 , are poured. The forms for the next level&#39;s floor  13  begin to be installed, requiring use of a fall arrest system. For prior art systems requiring tie-off to the concrete columns  16 , the concrete columns  16  are not of sufficient strength to support a user&#39;s weight until the 4 th  to 15 th  day following pouring the concrete. 
         [0013]    Typically, on the second day of construction, the installation of the form for the next level&#39;s floor  13  is completed, again requiring use of a fall arrest system. Also on the second day, reinforcing steel, conduit, and plumping pipes are installed on the forms. On the third day, the installation of the reinforcing steel, conduit, and plumping pipes is completed. On the fourth day, the concrete floor for the next level&#39;s floor  13  is poured and the cycle is started again. For a high rise construction where dozens of floors must be assembled, minimizing the time for this cycle is important. 
         [0014]    One embodiment of the invention relates to a fall arrest system  101 . The fall arrest system  101  includes at least one upright support  103 . The upright supports  103  provide a location for cables, ropes, lines and the like to be attached, providing a secure method for a worker to “tie-back”. The upright supports  103  include at least one sleeve  110  and post  120 . In one embodiment, the sleeve  110  and post  120  are integral, with the sleeve  110  being positioned at one end of the post  120 , such that the post  120  of another upright support  103  can engage the sleeve  110  to form a connection between the two upright supports  103 . In an alternative embodiment, the sleeve  110  and post  120  are separate, but engagable, components such that multiple posts  120  can be connected via sleeves  110  to form a series of connected upright supports  103 . In applications where multiple stories are involved, each upright support  103  may comprise a series of sleeves  110  and posts  120  stacked on top of each other to allow the height of the upright support  103  to increase as the construction moves upward with each increasing floor. 
         [0015]    Thus, where multiple posts  120  are stacked, lower-positioned posts  121  in the upright support  103  are contained within a column  16  of cured or substantially cured concrete, while the upper-positioned post  122  extends beyond the current level  12 . In one embodiment, a first end  114  of the upper most post  122  is substantially disposed within the cured column  16  or floor of the current level  12 . The upper-most post  122  may extend through a portion (shown as  17  in  FIG. 1 ) of the column  16  above the current level  12 . This column portion  17  may have varying degrees of structure including but not limited to having no structure, a rebar skeleton, or both rebar and uncured concrete. The degree of structure of the column portion  17  may change while the upper-most post  122  is in use, such as through the application of concrete to a rebar skeleton. It should also be appreciated that the upright supports  103  may be used where the portion  17  has been allowed to cure. Thus, the upright supports  103  are retained, at the lower levels, by cured concrete, but the upper most post  122  is retained by its interaction with the other upright supports  103 . 
         [0016]    The stacking of one post  120  on top of another post  120  will result in a moment being created when lateral force is exerted on the upper-most post  122 . In one embodiment, typically used to tie-off a single user, the cord  130  may extend from a user to the post  120 . In an alternative embodiment, typically used to tie-off multiple users, a line (not shown) is extended between two posts  120  and the cable  130  is attached to the line. The latter embodiment can also be utilized to provide for greater lateral movement by a user by utilizing a sliding connection between the cable  130  and the line. One type of force that may be exerted on the upper-most post  122  is from the cord  130  connecting the user to the upright support  103 . Lateral force (or any force having a lateral component) will result in the upper-most post  122  pivoting about a point such that the upper most post  122  will contact the column portion  17 , exerting force on the column portion  17 . To prevent this exertion of force on the column portion  17  (which may not be sufficiently cured to bear such a force), the sleeve  110  is utilized to counter the pivoting movement. The sleeve  110  operates to secure the upper-most post  122  to the immediately preceding post  120 . In embodiments where the sleeve  110  and post  12  are a singular unit, the upright supports  103  engage with each other, stacking by allowing the end of one upright support  103  to be disposed within the end of another upright support  103 . The interconnection of the sleeve  110  and posts  120  operates to resist lateral forces, such as those exerted by the cord  130  when a user falls. 
         [0017]    The sleeve  110  and the post  120  are engagable to secure the upright support  103 . The post  120  has a first end  124  and a second end  125 . The sleeve  110  has a first end  114  and a second end  115 . As depicted in the Figures, the first ends  124  and  114  are the “bottom” ends in relation to the ground. In one embodiment, the sleeve  110  and post  120  are engagable such that the second end  115  of the sleeve  110  is at least partially disposable within the first end  124  of the upper-most post  120  and the first end  114  of the sleeve  110  is disposed within the second end  125  of the immediately preceding post  120  in the upright support  103 . Thus each post  120  is connected via a sleeve  110  to another post  120 . In one embodiment, the sleeves  110  are left in place connecting the posts  120  above and below the sleeve  110  even after the corresponding level is completed and the concrete in the column  16  surrounding the post  120  has cured. In one embodiment, the sleeve length is determined based upon sleeve material; sleeve wall thickness, height of the post, number of users tied off at any given time and the overturning moment on the sleeve/post connection during a fall. In an exemplary embodiment, the sleeve and post diameters are about 4-6 inches. It should be further appreciated that the column need a certain cross sectional area of concrete in order to support the weight above it, as well as its own weight. For example, but without intent to limit, a 24″×24″ column has a cross sectional area of 576 sq in′. A 6″ sleeve removes 28 sq in or about 5% of the area. Thus, in one embodiment, it may be necessary for columns having the upright support  103  to be slightly larger than those without to support the intended design weight. However, it should be appreciated that in many instances, this difference in cross sectional area will be within standard construction tolerances and no modification to the columns will be necessary. 
         [0018]    In one embodiment where the sleeve  110  is internal to the post  120 , a sleeve retention mechanism  117  is utilized to prevent the sleeve  110  from sliding down into the lower post  121 . The sleeve retention mechanism  117  may include, in one embodiment, a protrusion or flange internal to the posts  121  spaced a distance from the second end  125  so as to allow the sleeve  110  to be sufficiently disposed within the post  120 . In an alternative embodiment, the sleeve  110  includes a flange that rests on the outer edge  127  of the second end  125  of the post  120 , positioned between the upper-most post  122  and the lower post  121 , retaining the sleeve  110  in position. In yet another alternative embodiment, the retention mechanism  117  comprises a pin, such as a piece of rebar (not shown), that is inserted into the second end  125  of the post  120 , such as through one or more holes (not shown), thus supporting the weight of the upright support  103  against the current level&#39;s floor  12  (using rebar as a “pin” to retain/support the post.) 
         [0019]    In an alternative embodiment shown in  FIG. 3 , the sleeve  110  is partially disposable within an end of the post  120 . As shown in  FIG. 3 , the sleeve  110  may be an integral component of the post  120 , such that the first end  124  of the post  120  fits into the second end  125  of the preceding post  120 . As with the embodiment of the sleeve  110  described above in reference to  FIG. 2 , the sleeve  110  of  FIG. 3  retains the post  120  against lateral movement such as that caused when a user&#39;s weight comes to bear against the post via the cable  130 . 
         [0020]    The sleeve  110  of the upright support  103  may be a separate component or may be an integral part of the post  120  as shown in  FIG. 3  or, as  FIG. 2  illustrates, the sleeve  110  may be a separate component. It will be appreciated that the interior separate sleeve  110  of  FIG. 2  could also be integral to either the first end  124  of the upper-most post  122  or the second end  125  of the lower post  121 , with the protruding portion of the sleeve engaging the other post respectively. Likewise, the exterior sleeve  110  of  FIG. 3  could be a separate component in accordance with an embodiment of the invention. 
         [0021]    While the invention may be utilized with the structures of  FIG. 1 , it will be appreciated that various embodiments of the invention can be utilized in other applications and situations.