US20090194368A1

US20090194368A1 - Portable roof anchor

Info

Publication number: US20090194368A1
Application number: US12/359,397
Authority: US
Inventors: Daniel W. Price
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-02-01
Filing date: 2009-01-26
Publication date: 2009-08-06

Abstract

A portable anchor for supporting a line along a side of a structure, having a beam member comprising a line support end and a counterweight end distal to the line support end, a counterweight attachable to the beam member at a counterweight location proximate the counterweight end, a support member that supports the beam member at a pivot location arranged between the line support end and the counterweight end, a line stand-off rotatably mounted to the support member and rotatable from a line deployed position and a storage position where the line stand-off guides the line away from the side of the structure in the deployed position; and an adjustable locking device that allows rotation of the support member, and selectably fixes the support member to the beam member at a selected angle.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the 2 Feb. 2008 filing date of U.S. Provisional Application 61/025,364 which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

This invention relates to the field of roof anchors for securing a line along a side of a structure.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 6,539,676, issued to the present inventor and incorporated by reference herein, describes a portable roof anchor that is small enough and light enough to be carried by one person. Such roof anchors are useful for accessing the sides of a building from a roof top via a rope that is secured to the anchor. Small portable roof anchors are generally useful for supporting only one man or a limited amount of equipment weight. It is desired to increase the versatility of a portable roof anchor without significantly decreasing its load carrying capability or portability or increasing its weight or portability.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in the following description in view of the drawings that show:

FIG. 1 is a side view of a first embodiment of a portable roof anchor.

FIG. 2 is a side view of a second embodiment of a portable roof anchor.

FIG. 3 is a side view of the standoff arm of the portable roof anchors of FIGS. 1 and 2.

FIG. 4 is a top view of the standoff arm of FIG. 3.

FIG. 5 is a side view of the adjustable locking apparatus of the portable roof anchors of FIGS. 1 and 2

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates one embodiment of a portable roof anchor 10 installed on the top of a building 14 having a generally flat roof 12 and a small parapet wall 13. 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 D₁from 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 D₂from pivot location 26. Beam member 20 may be upwardly 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 mechanical advantage provided by the ratio of D₂/D₁reduces the mass of the counterweight 32 that must be used in order to counterbalance a given line load. The ratio of D₂/D₁is 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.
Beam member 20 may be 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 D₂. The ratio of D₂/D₁may 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, and then reconfigured to a desired second length. To compensate for any reduction in length D₂necessary 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 support member such as 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. It is desired that 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. Prior art designs such as those described in U.S. Pat. No. 6,539,676 simply affix the two members 20, 44 at pivot location 26 by means of a bolted connection. The portable roof anchor 10 of the present invention accomplishes this joint with an adjustable locking apparatus 45, as will be described more fully below, in order to allow the beam 20 to be affixed to the bipod 44 at pivot point 26 at any of a plurality of selectable angles there between. The adjustable locking apparatus 45 allows for rotation of the bipod 44 relative to the beam member 20 about a horizontal axis through pivot location 26. A pivot location 27 is also provided for horizontal rotation of the beam member 20 relative to the bipod 44 about a vertical axis. Rotation about the horizontal axis at pivot location 26 allows the bipod 44 to be maintained at a desired back slant angle greater than 0°, for example 5-10°, relative to the surface it is placed on even when the height of bipod 44 is adjusted or when the bipod 44 is placed on a surface that is higher or lower than the roof surface 12 upon which the counterweight 32 is resting. Such back slant serves to increase the stability of the devise by insuring the weight of the load bears nearly straight down on the bipod 44, thereby virtually eliminating any forward pull forces on the apparatus. The adjustable locking apparatus 45 is joined to the beam member 20 with a rotatable joint such as a pin at pivot location 26. A notch 47 formed in the adjustable locking apparatus 45 (as shown more clearly in FIG. 5) is engaged over and rests on the head of the bipod 44 to prevent rotation of the adjustable locking apparatus 45 relative to the bipod 44. The beam member 20 can then be rotated relative to the bipod 44 and adjustable locking apparatus 45 about pivot location 26 to a desired rotational angle, and it is then secured at the selected position by inserting a bolt through one of the positioning holes 49 that becomes aligned with a hole (not shown) formed through the beam member 20. A plurality of discrete positioning holes may be provided to allow for a range of predetermined angles with maximum strength of the joint, or a curved slot may be used for infinite positioning flexibility with less strength in the joint. FIG. 5 shows locking apparatus 45 with a combination of discrete holes 49 and slot 70 for purposes of illustration, however, in various embodiments the locking apparatus 45 may have only discrete holes 49 or only slot 70 or both. Optionally, a rotatable joint 27 allows rotation about an axis 71 perpendicular to a longitudinal axis of the beam member 20 so that the counterweight 32 and counterweight end of the beam member 20 may be moved along the roof surface 12 without moving the bipod 44, such as may be useful to avoid an obstruction on the roof for a particular application. Once in the desired position, a bolt/nut combination is tightened to secure the rotatable joint 27.
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 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.
In another embodiment as shown in FIG. 2, the line storage member may be a roller mechanism 59 that allows the line 16 to be rolled off of the roller mechanism 59 to lower the supported load downward along the side of the structure 14 and drawn back onto the roller mechanism 59 to draw the supported load upwardly. In such an embodiment, the line is not affixed to a line support member 28 as shown in FIG. 1, but rather is looped over a pulley 61 disposed at the line support end of the beam member, as shown in FIG. 2. Pulley 61 may be attached to beam member 20 via an adjustable support in order to provide proper alignment of the roller mechanism 59 and pulley 61 whenever an angle is created around the vertical axis at pivot location 27.
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 D₂. 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.
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 (eyebolt) 28 is attached to the inner tube approximately 3 inches (D₁) 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 D₂dimension ranging from about 5 feet or about 6 feet to about 10 feet (in various embodiments) in 6 inch increments, thus providing a ratio of D₂:D₁of 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 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 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, or with a bipod capable of extending to different heights to accommodate varying parapet wall heights. Advantageously, as the inclination angle of the beam member 20 is changed in different applications, the angle of the bipod 44 can be maintained at a desired 5-10° back slant relative to the surface that it is resting on by operation of adjustable locking apparatus 45 as described above.
Referring back to FIG. 1, the portable anchor 10 may also be provided with a standoff arm 11. Standoff arm 11 is illustrated in more detail in the side view of FIG. 3 and the top view of FIG. 4. The standoff arm 11 is rotatably attached to the bipod 44 at pivot location 15 so that it may be moved from an uppermost position storage position (not shown) where it is drawn into the bipod 44 for ease of portability to a deployed lowermost position (as illustrated in FIGS. 1 and 2) where it engages line 16 at line support bar 19 and urges the line away from the bipod 44 and away from the vertical side 18 of building 14. The line support bar 19 may be affixed at any of several positions along the length of the standoff arm 11 to provide a selectable degree of line standoff. The standoff arm 11 is held at its lowermost position and prevented from further rotation by the engagement of the top surface of its rearwardly extending portion 17 with a horizontal cross brace member of bipod 44. Advantageously, the standoff arm 11 defines an angle with the plane of the uppermost section of the bipod 44 of greater than 90° plus the back slant angle of the bipod 44 when in its lowermost position So that the weight of the line 16 against the line support bar 19 urges the standoff arm 11 downward without the need for a locking mechanism. When the bipod 44 is positioned at an angle of 5-10° back slant relative to the roof surface, the angle between the standoff arm 11 and the upper section of the bipod 44 may be more than 90°+10° or more than 100°, or in one embodiment at least 105° or about 107° to provide a small downward angle relative to horizontal. In this manner, the weight of line 16 will keep the rearwardly extending portion 17 of standoff arm 11 urged against the cross brace of bipod 44 during use, but will allow the standoff arm 11 to be folded upward against the bipod 44 easily when not in use.
While various embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions may be made without departing from the invention herein.

Claims

1. A portable anchor for supporting a line along a side of a structure, comprising:

a beam member comprising a line support end and a counterweight end;

a counterweight attachable to the beam member at a counterweight location proximate the counterweight end;

a support member that supports the beam member at a pivot location arranged between the line support end and the counterweight end;

a line stand-off rotatably mounted to the support member and rotatable between a line deployed position and a storage position, where the line stand-off guides the line away from the side of the structure in the deployed position; and

an adjustable locking apparatus that allows rotation of the support member relative to the beam member, and selectably fixes the support member to the beam member at a selected angle.

2. The portable anchor as claimed in claim 1, further comprising a rotatable joint arranged along the beam member, the rotatable joint configured to permit a rotation of the line support end relative to the counterweight end about an axis perpendicular to a longitudinal axis of the beam member.

3. The portable anchor as claimed in claim 1, wherein the adjustable locking apparatus is configured to fix the support member to the beam member at any one of a plurality of predetermined angles.

4. The portable anchor as claimed in claim 1, wherein the adjustable locking apparatus is configured to fix the support member to the beam member at any angle within a range between a first angle and a second angle.

5. The portable anchor as claimed in claim 1, wherein the line stand-off comprises a line support bar that engages the line.

6. The portable line support as claimed in claim 5, wherein the line support bar is affixable at a plurality of locations along the line stand-off such that a selectable degree of line stand-off from the side of the structure is provided.

7. The portable line support as claimed in claim 1, wherein the line stand-off when rotated into a lowermost deployed position contacts a portion of the support member to prevent further lower rotation of the line stand-off, and a point of contact between the line stand-off and the line is vertically below a point of rotation of the line standoff such that a tension of the line acting against the line support bar provides a downward force to the line stand-off that operatively fixes the line stand-off in the lowermost deployed position during use without the need for a locking mechanism.

8. A portable line support, comprising:

a beam member comprising a line support end and a counterweight end;

a support member that vertically supports the beam member; and

an adjustable locking apparatus that:

allows rotation of the support member relative to the beam member about a pivot axis, and

selectively fixes the support member to the beam member at a selected angle.

9. The portable line support as claimed in claim 8, further comprising a rotatable joint arranged along the beam member, the rotatable joint configured to permit a rotation of the line support end relative to the counterweight end about an axis perpendicular to a longitudinal axis of the beam member.

10. The portable line support as claimed in claim 8, wherein the adjustable locking apparatus is configured to fix the support member to the beam member at any one of a plurality of predetermined angles.

12. The portable line support as claimed in claim 8, wherein the adjustable locking apparatus is configured to fix the support member to the beam member at any angle within a range between a first angle and a second angle.

13. The portable line support as claimed in claim 8, further comprising a line stand-off rotably attached to the support member and comprising a line support bar that guides the line away from a side of a structure when in a deployed position.

14. The portable line support as claimed in claim 13, wherein the line support bar is affixable at a plurality of locations along the line stand-off such that a selectable degree of line standoff from the side of the structure is provided.

15. The portable line support as claimed in claim 13, wherein the line stand-off when rotated into a lowermost deployed position contacts a portion of the support member to prevent further lower rotation of the line stand-off, and a point of contact between the line support bar and the line is vertically below a point of rotation of the line standoff such that a tension of the line acting against the line support bar provides a downward force to the line standoff that operatively fixes the line standoff in the lowermost deployed position during use without the need for a locking mechanism.

16. An apparatus for supporting a line, comprising:

a beam member having a line support end, a counterweight end and a pivot location arranged between the line support end and the counterweight end;

a support member that supports the beam member at the pivot location; and

a line stand-off rotatably mounted to the support member, where the rotatable line stand-off guides the line away from a side of a structure when in a deployed position.

17. The apparatus as claimed in claim 16, further comprising a rotatable joint arranged along the beam member, the rotatable joint configured to permit a rotation of the line support end relative to the counterweight end about an axis perpendicular to a longitudinal axis of the beam member.

18. The apparatus as claimed in claim 16, wherein the line stand-off comprises a line support bar that engages the line.

19. The apparatus as claimed in claim 18, wherein the line support bar is affixable at a plurality of locations along the line stand-off such that a selectable degree of line standoff from the side of the structure is provided.

20. The apparatus as claimed in claim 18, wherein the line stand-off when rotated into the deployed position contacts a portion of the support member to prevent further lower rotation of the line stand-off, and a point of contact between the line support bar and the line is vertically below a point of rotation of the line standoff such that a tension of the line acting against the line support bar provides a downward force to the line standoff that operatively fixes the line standoff in the deployed position during use without the need for a locking mechanism.