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This application claims benefit of the Aug. 4, 2000, filing date of U.S. provisional patent application No. 60/223,081. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to the field of roof anchors for securing a line along a side of a structure, and in particular to such roof anchors that are small enough and light enough to be carried by one person. 
     BACKGROUND OF THE INVENTION 
     The maintenance of a modern high-rise building often necessitates men and/or machines being supported along the sides of the building for window cleaning, painting, inspection or repair activities. Some buildings have specially designed equipment and/or permanent tie-down locations associated with the building for supporting such activities. However, some buildings have no such accommodations, and special removable rigs must be delivered to the building each time such activities are performed. 
     Many types of roof rigs are known in the art for anchoring a line from the top of a building. Two such machines sold under the marks “Little Boss” and “Big Boss” by Finn&#39;s Corporation (www.finnsboss.com) are adjustable to accommodate parapet walls of varying sizes. These machines weigh at least 250 pounds and are moved about the building roof on wheels. Such systems are difficult to deliver to the roof top and difficult to maneuver around obstacles on a roof. 
     Another known roof rig sold under the mark “Skyhook” by Skyhook Systems (www.skyhooksystems.com) is a motorized rolling roof rig with computerized controls. Such systems are heavy, complicated and expensive. 
     The roof rig sold under the mark “MIO-250” by J. Racenstein &amp; Co., Inc. (www.windocleaningsupplies.com) is designed to fold together into a reduced-size package for delivery to a job site. However, even when folded, this machine is large and heavy enough to need wheels for easy movement, and it has a shape that makes it virtually impossible for one man to carry. This machine weighs over 400 pounds with counterweights. 
     The roof rigs sold by B. H. Rigging Distributors were relatively simple in design and somewhat lighter than some other designs. However, these rigs are still difficult to maneuver around obstacles on a roof, and they have limited flexibility for accommodating the many different physical limitations that may be encountered on various roofs. This company has also sold roof rigs that have a generally U-shape and are designed to mount over a parapet wall. While these devices are light and easy to carry, it is difficult for a person who is suspended from such a device to return to the top of the roof. 
     Fitch-Enterprises Ltd. sells roof rigs that include optional extension pieces for increasing or decreasing the overall length of the device. For example, the machine sold under the mark “Fitch Horse” may be used with one standard eight foot beam length, or an additional eight foot extension may be added to achieve an overall length of sixteen feet. This limited degree of adjustment in the length of the device is not adequate to accommodate every roof condition. Furthermore, the device weighs 160 pounds without counterweights. An additional 200 pounds of counterweight must be attached prior to use, and it must be disassembled to fit into a standard elevator or through a roof hatchway. 
     SUMMARY OF THE INVENTION 
     Accordingly, there is a need for an improved portable roof anchor device that is light enough to be handled by one man, that is flexible enough to accommodate a large variety of space limitations, that can be easily maneuvered around obstacles on a roof, and that is relatively inexpensive to manufacture when compared to the prior art devices described above. A roof rig is needed that can accommodate a parapet wall, while at the same time making it easy for a user to rappel from a rooftop. 
     A portable anchor designed specifically for supporting a line along a side of a structure is described herein as including: a beam member having a line support end, a counterweight end, and a pivot location; a line support member attached to the beam member at a line support location proximate the line support end; a counterweight attached to the beam member at a counterweight location proximate the counterweight end; wherein the beam member is slidably extendible in length so that the distance from the counterweight location to the pivot location may be fixed at any of a plurality of lengths. The portable anchor may include: a hollow outer member and an inner member extending partially into the hollow outer member and slidably moveable therein to be fixed at any of the plurality of lengths. The portable anchor may be carried in a line-deployed configuration by a single person having one hand holding a handle on the counterweight side of a center of gravity of the assembly and a second hand cradling the beam member between the center of gravity location and the line support end. 
     The portable anchor may further include a pair of line storage members attached to the beam mechanism, so that when the line is wrapped around the line storage members, the line forms a handle for carrying the beam member. 
     The counterweight may have a generally triangular shape rotatably attached to the beam member proximate a corner of the generally triangular shape so that a flat side of the counterweight is self-leveling. The counterweight may further include: a weight member having a hole formed there through; a bolt member having a head end and having a threaded end opposed the head end, the bolt member adapted for passing through a hole formed in the beam member and through the hole formed in the weight member; a handle member attached to the head end of the bolt member; a spacer member attached to the bolt member a predetermined distance from the handle member, the spacer member adapted to space the weight member from the handle member when the bolt member is disposed through the hole formed in the weight member; and a nut adapted to thread onto the threaded end of the bolt member for urging the weight member toward the spacer member and for retaining the counterweight on the beam member. 
     Such a device may be used for supporting a line over an edge of a structure by: providing a beam member having a line support end and a counterweight end, the beam member comprising a hollow outer member and an inner member slidably extending at least partially into the hollow outer member and fixable at a plurality of positions for providing the beam member with a respective plurality of lengths; positioning the beam member on a top of a structure at a working location; adjusting the length of the beam member to a maximum length permitted by the working location; connecting a counterweight to the beam member proximate the counterweight end; connecting a line to the beam member proximate the line support end; supporting the beam member at a pivot location of the beam member between the line support end and the counterweight end; and dropping the line over an edge of the structure. The beam member will have a center of gravity location when in a line-deployed configuration with the line and the counterweight connected to the beam member, and the anchor may be moved about the roof by attaching a handle to the beam member at a location between the counterweight end and the center of gravity location so that the beam member may be carried in the line-deployed configuration by a person having one hand holding the handle and a second hand cradling the beam member between the center of gravity location and the line support end. The device may also be carried to the roof by: attaching a line storage member to the beam member; wrapping the line around the line storage member; and using the line as a handle to carry the beam member. 
     The counterweight may be provided to have a generally triangular shape and pivotally connected to the beam member so that the counterweight will self-level with a bottom edge of the generally triangular shape in a horizontal position. This may be accomplished by providing a hole in the counterweight and a hole in the beam member; providing a bolt member having a head end and having a threaded end opposed the head end, the bolt member adapted for passing through the hole formed in the beam member and through the hole formed in the counterweight; attaching a handle to the head end of the bolt member; attaching a spacer member to the bolt member a predetermined distance from the handle member, the spacer member adapted to space the weight member from the handle member when the bolt member is disposed through the hole formed in the weight member; and threading a nut onto the threaded end of the bolt member for urging the weight member toward the spacer member and for retaining the counterweight on the beam member. In this manner, the counterweight may be carried separately from the beam member by passing the threaded end of the bolt member through the hole formed in the counterweight and tightening the nut against the counterweight with the handle in a predetermined position relative to the counterweight so that the counterweight is balanced when carried by the handle. 
     A portable anchor for supporting a line along a side of a structure having a parapet is described herein as including: a generally U-shaped member comprising a horizontal member, an inner vertical member extending downward from the horizontal member, and an outer vertical member extending downward from the horizontal member on a side of the horizontal member opposed the inner vertical member, the generally U-shaped member adapted to fit over a parapet; a step member attached to the outer vertical member and extending away from the outer vertical member; and a hand hold attached to the outer vertical member. The hand hold may include a bottom end attached to the outer vertical member at an angle of less than ninety degrees so that a line passing through the opening will be drawn against the outer vertical member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a portable roof anchor installed on a roof of a building. 
     FIG. 2 is a partial rear cross-sectional view of a counterweight assembly rotatably attached to a beam member by an L-handle bolt and nut combination. 
     FIG. 3A is a top view of a half-moon shaped counterweight configured to be carried by an L-handle bolt and nut combination. 
     FIG. 3B is a top view of a T-shaped shaped counterweight configured to be carried by an L-handle bolt and nut combination. 
     FIG. 4 is a side view of a portable roof anchor installed on a roof of a building having a parapet. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates one embodiment of a portable roof anchor  10  installed on the top of a structure, here the flat roof  12  of a building  14 . The portable roof anchor  10  may be used for supporting a line  16  along a vertical side  18  of the building  14 , such as for cleaning the exterior of the windows of the building or for performing other maintenance activities along the vertical side  18  of the structure. The line may be a cable, rope, wire or other load carrying material as may be used for suspending a machine or person along the side  18  of the building  14 . 
     Roof anchor  10  includes a beam member  20 . Beam member  20  is illustrated as a linear-shaped structure having a line support end  22 , a counterweight end  24 , and a pivot location  26 . Beam member  20  may have any desired cross-sectional shape for carrying bending moment loads, such as an I-beam, tube, bar or channel, for example. Beam member  20  may be formed of any metal, alloy or composite material and is preferably formed of a material having a high strength-to-weight ratio in order to improve the portability of the device. The cross-section of the beam member  20  may be different at different points along the length of the beam member  20 . For example, to increase the lifting capability of the device for rescue applications, it may be necessary to form at least a portion of the beam member near the pivot location, where the bending moments will be the highest, from a solid bar of material, while a portion of the beam member having a lower level of stress may be formed from an open channel material. 
     A line support member  28  is attached to beam member  20  at a line support location  30  proximate the line support end  22 . Line support member  28  may be a turnbuckle, hook, or a groove or notch formed in the beam member  20 . Alternatively, line  16  may simply be tied or wrapped around beam member  20  at line support location  30  depending upon the safety requirements of a particular application. Line support location  30  is located a distance D 1  from pivot location  26  along the length of beam member  20 . A counterweight  32  is attached to the beam member  20  at a counterweight location  34  located a distance D 2  from pivot location  26 . Beam member  20  may be supported at pivot location  26  so that the downward force exerted on the line support member  28  is counterbalanced by the downward force exerted by the counterweight  32 . The greater the mechanical advantage provided by the ratio of D 2 /D 1 , the smaller the mass of the counterweight  32  must be in order to counterbalance a given line load. The ratio of D 2 /D 1  is selected so that when the beam member  20  is vertically supported at the pivot location  26 , the moment of inertia about the pivot location  26  created by the counterweight  32  will exceed the moment of inertia about the pivot location  26  created by a line  16  connected to the line support member  28  by a predetermined safety margin; for example, a 4:1 safety margin. 
     In a preferred embodiment, beam member  20  is formed to be expandable along its length dimension so that it may be carried to the roof  12  of a building  14  in one configuration having a first shorter length, then reconfigured while on the roof  12  to a second configuration having a greater length. In this manner, beam member  20  may be more conveniently carried through stairways, elevators or other roof access openings without being disassembled. In the embodiment of FIG. 1, beam member  20  includes a hollow outer member  36  and an inner member  38  slidably extending partially into the hollow outer member  36 . A plurality of holes  40  are formed at various locations on the inner member  38  so that a removable connector, such a bolt  42  and mating nut (not shown) may be used to lock the two portions of the beam member  20  together to have a selected length D 2 . The ratio of D 2 /D 1  may thus be varied, for example from 20:1 to 40:1. In this manner, portable anchor  10  may be used in a variety of locations, some of which do not provide sufficient space for the extension of beam member  20  to its full length. Furthermore, beam member  20  may be delivered to the roof  12  in a first configuration having its shortest length to simplify the delivery process, then reconfigured to a desired second length. To compensate for any reduction in length D 2  necessary to accommodate a job-specific physical interference, a corresponding increase in the weight of counterweight  32  or a reduction in the line load may be provided. 
     The vertical support of beam member  20  may be provided by a bipod  44  having a ladder-style support foot  46  pivotally connected to each leg. Bipod  44  is connected to beam member  20  at pivot location  26  by any known type of mechanical connection, and preferably a connection providing at least some horizontal support between the two structures  20 ,  44 . Furthermore, vertical support member  44  should be restrained from rotating with respect to beam member  20  about pivot location  26  in order to prevent the roof anchor  10  from collapsing, thereby presenting an unsafe situation. 
     A handle  48  may be attached to beam member  20  for carrying of the device. Handle  48  may also function as a location for connecting a safety line  50  to the roof anchor  10 . The handle  48  is preferably located a short distance toward the counterweight end  24  from a line-deployed center of gravity location  52 . In one embodiment, this distance may be approximately 12-18 inches. In this manner, a single person may easily lift and move the roof anchor  10  with the attached counterweight  32  and deployed line  16  by placing one hand on the handle  48 , and by cradling the beam member  20  with the other hand positioned at a location between the center of gravity  52  and the line support end  22 . By using such a strategically located handle, the operator is able to easily lift, tilt and turn the roof anchor assembly  10  in its deployed configuration with the line  16  over the side  18  of the building  12  in order to move from place to place while avoiding any obstacle on the roof. For example, lightning rods are commonly mounted to a parapet on a corner of a building. With prior art roof rigs, it was necessary to retrieve the entire line in order to move from one side of a lightning rod to another, since such rigs were too heavy or bulky to be lifted. In one embodiment, the portable roof anchor of FIG. 1 with 300 feet of {fraction (7/16)} inch nylon mountain-climbing rope and counterweights attached may weigh only about ninety pounds. One person lifting the device  10  with one hand on handle  48  and one hand cradling under the beam member  20  can easily tilt the line supporting end  22  upward to clear a lightning rod with the line  16  fully deployed. Similarly, an operator can step over or around obstacles on the roof  12  which would be difficult to maneuver around with a prior art wheeled device. 
     A line storage member such as brackets  54  may also be attached to beam member  20 . Line  16  may be wrapped around the brackets  54  for transport, and may be securely tied or otherwise affixed to brackets  54  when in use for supporting a load along a side  18  of building  14 . Other styles of line storage members may be used, such as a single unit having two opposed raised members for wrapping the line  16 . Furthermore, when line  16  is wrapped around the line storage member, the line itself may serve as a handle or shoulder pad  56  for carrying the device. By spacing brackets  54  apart and on either side of a center of gravity  58  of the device in its line-stored configuration with the counterweight  32  removed, the line handle  56  may be held with one hand or two, or it may be slung over the shoulder of the person carrying the device to and from a roof  12 . 
     Counterweight  32  may be a single weight member or a plurality of individual weight members. Counterweight  32  is connected to beam member  20  at or very close to the counterweight end  24  in order to maximize dimension D 2 . Unlike prior art devices, roof anchor  10  advantageously uses the counterweight  32  as a foot for resting on the roof  12 , thereby eliminating the cost and weight associated with a separate foot/wheel structure at the counterweight end  24 . Counterweight  32  may preferably have a bottom portion cross-sectional area that is greater than a top portion cross-sectional area, such as the generally triangular shape as seen from perspective of the side elevation view of FIG.  1 . Other such shapes include a half-moon shape and an inverted T-shape as viewed from a side perspective. By rotatably connecting the counterweight  32  to the beam member  20  within its top portion, the counterweight  32  becomes self-leveling with the relatively larger flat bottom surface being horizontal no matter what angle the beam member  20  has to the horizon. Because the counterweight  32  rests directly on the roof  12 , this advantageously provides a large, flat bottom surface to reduce the weight per unit area exerted on the roof  12 . This structure also provides a relatively taller counterweight  32 , which may be advantageous if it becomes desirable to have a winch  60  or other device mounted on the bottom of beam member  20 . This type of counterweight shape also provides a very stable base for resting the portable anchor  10  on the roof  12 . 
     FIG. 2 illustrates a partial rear cross-sectional view of a counterweight assembly  70  installed on a beam member  72 . The counterweight assembly  70  includes four individual weight members  74  rotatably attached to the beam member  72  in a top portion of the half-moon shape. Additional weight members may be used if necessary to carry a heavier load or to compensate for a shorter beam length. A bolt member  76  having a head end  78  and having a threaded end  80  opposed the head end  78  passes through holes formed in the weight members  74  and the beam member  72 . A handle member, such as L-handle  82  is attached to the head end  78 , such as by welding a bar to a standard bolt. A spacer member such as washer  84  is attached by weld  86  to bolt member  76  at a predetermined distance from the handle member  82 . Spacer member  84  functions to space the weight members  74  away from the handle member  82  when nut  88  is threaded onto bolt member  76  to urge the weight members  74  toward the spacer member  84 . A retainer device such as pin  90  may be used to ensure that the nut  88  does not become unintentionally disengaged from bolt member  76 . By only tightening nut  88  to a finger tight condition, the weight members  74  are free to self-level as beam member  72  is moved about. 
     When transporting the weight members  74  to the top of a structure  14 , they may be removed from the beam member  72 , installed on the bolt member  76 , and tightened firmly against spacer member  84  by nut  88 . FIGS. 3A and 3B are top views of a stack of half-moon shaped counterweight members  92  and a T-shaped counterweight members  94 , respectively, in a transportation configuration having an L-handle  96  attached by a bolt member (not visible) to a spacer member  98  and tightened against the counterweights by a nut (not visible). By positioning and tightening the L-handle  96  over a center-of-gravity of the stack of counterweight members  92 ,  94 , the entire group of counterweight members may be balanced and carried with one hand. 
     In one embodiment, beam member  20  includes a 2½ inch square, high strength aluminum alloy tube with a wall thickness of 0.125 inch as the outer member  36  and a mating inner member having a wall thickness of 0.1875 inch. A standard 2 inch turnbuckle  28  is attached to the inner tube approximately 3 inches (D 1 ) from the pivot location  26 . The overall length of the beam member  20  may be adjusted by sliding the inner member  38  into the outer member  36  to obtain a D 2  dimension ranging from about 5 feet to 10 feet in 6 inch increments, thus providing a ratio of D 2 :D 1  of about 20:1 to 40:1. A plurality of counterweights  32  may be connected to the beam member  20  to provide a desired load supporting capability. The counterweights may be steel plate, each weighing about 11 pounds. The bipod  44  may be formed to include a top pair of opposed angle brackets  54  which together define a channel into which the inner tube  38  may be placed and affixed. The bipod  44  may support the beam member  20  about 17½ inches above the rooftop  12 . The total weight of such an assembly, including 46 pounds of counterweight and 300 feet of {fraction (7/16)} inch diameter nylon line would be about 92 pounds, light enough to be conveniently handled by one person. The counterweights may be removed from the beam and carried separately, then reassembled on the rooftop  12  at a working location. The length of the beam assembly  20  may then be adjusted to a maximum length permitted by any obstructions present at the working location. 
     Not all building roofs are flat. The roof anchor  10  can also be used on a peaked roof by positioning the bipod feet  46  on one side of the roof, at or very near to the peak of the roof. The line  16  would then be routed along the opposite side of the roof and over the side of the building. The line load would then be transferred to the beam member  20  and resisted by the bipod support  44  in much the same manner as described above, but with the axis of the loads being rotated from horizontal/vertical by the angle of the roof. The portable roof anchor  10  may also be used on a roof having a parapet by placing the bipod feet  46  on the top of the parapet, or by providing a bipod  44  having sufficient height to clear the beam member  20  over the parapet. Alternatively, the device may be used without a bipod  44  by laying the beam member directly onto the parapet at the pivot location  26 , or with different bipod heights to accommodate varying parapet wall heights. 
     One skilled in the art may appreciate that when using a portable roof anchor, it is difficult to step over the edge of the building and to step back onto the roof while being supported only by a tie line. These maneuvers are made even more difficult on roofs having a parapet. Accordingly, a portable roof anchor  100  is illustrated in FIG. 4 as installed over a parapet wall  102 . The portable anchor  100  is a generally U-shaped member having a horizontal member  104 , an inner vertical member  106  extending downward from the horizontal member  104 , and an outer vertical member  108  extending downward from the horizontal member  104  on a side of the horizontal member  104  opposed the inner vertical member  106 . There may be an adjustable connection  107  between the horizontal member  104  and at least one of the inner vertical member  106  and outer vertical member  108  to adapt the device to fit over parapets  102  having a plurality of widths. Advantageously, the anchor  100  also includes a step member  110  attached to the outer vertical member  108  and extending in a generally horizontal direction away from the outer vertical member  108 . The step member  110  may include an end  112  opposed the generally U-shaped member  100  being angled upward from horizontal to serve as a foot stop. A top surface  114  of the step member  100  may have a non-slip coating or surface finish of any type known in the art. An adjustable wall stop  116  may be connected to the inner vertical member  106  opposed the horizontal member  104  for securing the generally U-shaped member  100  against the parapet  102 . A hand hold  118  is attached to the outer vertical member  108  to provide a convenient location for a user to hold onto the portable roof anchor  100  while standing on the step member  110  and while moving onto and off of the roof surface  120 . The hand hold  118  has a bottom end  122  attached to the outer vertical member  108  at an angle of less than ninety degrees, for example 20 degrees, so that a line  124  passing through the opening  126  formed by the hand hold  122  will be drawn against the outer vertical member  108 . The portable roof anchor  100  can be easily carried to the roof surface  120  by one person, adjusted to accommodate any width of parapet  102 , for example up to 15 inches in width, then installed at any desired working location. The user makes an attachment to the line  124 , then while holding onto handhold  122 , steps over the parapet  102  onto step member  110  before rappelling down the side of the building. Upon returning to the rooftop  120 , the user may use the handhold  122  while stepping on the step member  110  for an easy return over the parapet  102 . 
     While the invention has been described herein with reference to particular embodiments, it will be understood by those skilled in the art that various changes may be made and various equivalents may be substituted for elements thereof without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed herein, but that the invention will include all embodiments falling within the scope of the appended claims.

Summary:
A portable roof anchor having a slidably adjustable beam member is supported at a pivot location near a line support end and at an opposed end by a rotatably attached self-leveling counterweights. A line wrapped onto the beam member may be used as a handle for carrying the beam member to a roof top, then used to support a person or equipment over a side of the building. The counterweights have a relatively small top cross-section and a relatively large bottom cross-section so that, for any given amount of weight, a relatively large bottom surface area and a relatively tall height from the rooftop will be provided. A handle is provided near a line-deployed center-of-gravity so that the roof anchor assembly may be easily maneuvered, while the line remains over the side of the building, with one hand on the handle and a second hand cradled underneath the beam member. An L-handle bolt/nut combination may be used to rotatably attach the counterweights to the beam member, and also to configure the unattached counterweights into an easily carried, balanced assembly. A parapet mounted portable roof anchor includes a step member and a hand hold to facilitate a person&#39;s movement off of and back onto the roof.