US20120222370A1

US20120222370A1 - Force distribution and attenuation device for use in a roof anchor safety system

Info

Publication number: US20120222370A1
Application number: US13/040,644
Authority: US
Inventors: Lawrence A. Crookston
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-03-04
Filing date: 2011-03-04
Publication date: 2012-09-06

Abstract

An anchor-to-lanyard adjustable riser cable with a choke and bearing plate. The device is positioned between a roof truss and a safety anchor system to better distribute the weight of a roofer on the truss in the event the roofer falls. The bearing plate is configured to engage a portion of the truss and to distribute forces into this structural member, thereby leading to attenuation of those forces. The bearing plate is provided with a non-skid surface to resist movement of the same along the structural member. Guide channels are provided on the bearing plate to receive portions of the cable from the cable choke therethrough. The bearing plate aids in protecting the structural member from being damaged by a lanyard extending to the safety harness in response to forces generated by the falling roofer.

Description

BACKGROUND OF THE INVENTION

1. Technical Field
This invention generally relates to safety systems. More particularly, the invention relates to a safety system for a roof anchor. Specifically, the invention relates to device that is engaged between a roof truss and a roof anchor safety system for distributing and attenuating the forces that would be applied to the truss and roof sheathing in the event of a roofer falling while being secured to the truss by a safety harness.
2. Background Information
There are a variety of roof anchor safety systems that are used by roofers to ensure their safety while they are working on a roof. The safety harness is worn on the body and is connected by a steel cable to an anchor that is temporarily or permanently mounted on some region of the roof truss system. Should the roofer slip or fall, the cable connected to the anchor will tend to prevent them from falling off the roof and being severely injured.
One of the problems in previously known safety systems is that the anchor is typically mounted on the peak or on the opposite side of the truss from where the roofer is working. This means that the steel cable extending between the anchor and the safety harness lanyard worn by the roofer is typically fed over the wood that forms the peak of the roof truss and is in direct contact with the sheathing that forms the base of the roof between the trusses. Since the cable is made from steel, it can cause substantial damage to the truss peak and to the plywood sheets that are used as sheathing in the event that the roofer slips or falls. This damage is essentially caused as the steel cable slams with force into the wood or plywood when the cable connected to the safety harness lanyard suddenly has to bear the roofer's full weight. The impact of the cable can slice and splinter the wood or sheathing and potentially damage the structural integrity of the same.
There is therefore a need in the art for an improved safety anchor system that will tend to distribute and attenuate the forces involved in the event of this type of accident and which will thereby tend to minimize the potential damage to the wooden components of the roof.

BRIEF SUMMARY OF THE INVENTION

The present invention is an anchor-to-lanyard adjustable riser cable with a choke and bearing plate that is positioned between a roof truss and a safety anchor system for distributing and attenuating the forces that would be applied to the truss and roof sheathing in the event of a roofer falling while being secured to the truss by a safety harness. In addition, the device transfers the energy force from the bottom of the truss rafter and the anchor connector plate to the top of the truss rafter when an attached workman slips or falls from the roof. This force transfer is important, creating a direction of force that favorably compresses the peak truss rafter joint rather than causing a horizontal pulling force on the lower portion of the truss connector plate. The device thus better distributes a roofer's weight and attenuates forces generated by the roofer falling than would be the case if the roofer's safety harness was directly secured by a cable or lanyard to a roof anchor on the truss. The bearing plate is configured to engage a portion of the truss and is provided with a non-skid surface to resist movement therealong. The bearing plate distributes the forces over a wider region of the truss than if only a cable connected the truss and harness. The plate protects the truss and roof ridge from possible damage when the lanyard suddenly is pulled taut and also aids in protecting the sheathing on the opposite side of the roof ridge. The choke is used to adjust the riser length.
The device of the present invention does not aid the anchor system in arresting the fall of the roofer. It does, however, offer a measure of protection to the structural members of the roof in the event of a roofer's fall so that those structural members remain capable of performing as intended for the useful life of the building.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Preferred embodiments of the invention, illustrated of the best modes in which Applicant contemplates applying the principles, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is a perspective view of a building showing a roof truss having an anchor plate engaged therewith and showing a force distribution and attenuation device in accordance with the present invention engaged with the anchor plate;

FIG. 2 is an enlarged front view of the peak of the roof truss showing the anchor plate and a first embodiment of the force distribution device in accordance with the present invention;

FIG. 3 is a rear perspective view of the force distribution device and showing a first embodiment of a bearing plate utilized therein;

FIG. 4 is a rear perspective view of bearing plate;

FIG. 5 is a front perspective view of the bearing plate; and

FIG. 6 is a side view of the force distribution device shown engaged with a clip and a portion of a lanyard that is connectable to a safety harness;

FIG. 7 is a top perspective view of a second embodiment of a force distribution device for a roof anchor safety system in accordance with the present invention shown engaged on a truss and including a second embodiment of a bearing plate utilized therein;

FIG. 8 is a top perspective view of the second embodiment of the bearing plate shown engaged on the roof truss;

FIG. 9 is a top perspective view of the bearing plate of FIG. 8;

FIG. 10 is a bottom perspective view of the bearing plate of FIG. 8;

FIG. 11 is a side view of the bearing plate of FIG. 8;

FIG. 12 is a top perspective view of a third embodiment of a force distribution device for a roof anchor safety system in accordance with the present invention shown engaged on a truss and including a third embodiment of a bearing plate utilized therein;

FIG. 13 is a top perspective view of the third embodiment of the bearing plate;

FIG. 14 is a perspective view of a building showing the use of a separator bar for securing a portion of a safety harness lanyard to two force distribution devices of the type illustrated in FIG. 13; and

FIG. 15 is a top view of a portion of a building roof showing the separator bar engaged with the two force distribution devices. Similar numbers refer to similar parts throughout the drawings.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 there is shown a building 10 having left and right side walls 12, 14 and a roof 16 that is being constructed disposed there between. Roof 16 is constructed from a plurality of roof trusses 18, two of which are illustrated in this figure, and sheathing 20 which consists of a plurality of sheets of plywood that are secured to trusses 18. Although not illustrated herein, roof shingles or other materials will ultimately be applied over sheathing 20.
Each roof truss 18 is comprised of a plurality of wood rafters 22 that are secured together by a plurality of steel plates 24. In particular, roof truss 18 includes an anchor plate 26 that is engaged with rafters 22 adjacent the peak 28. Anchor plate 26 is preferably a plate such as those disclosed in U.S. Pat. Nos. 7,380,373 and 7,832,153 issued to the present inventor.
As shown in FIG. 2, anchor plate 26 comprises a body 30 that is secured to rafters 22 by a plurality of projections 32 extending outwardly from a rear face of plate 26 and driven into the wood of the rafters. Plate 26 defines one or more holes 34 therein for securement of a safety anchor system to truss 18. For the sake of clarity, only a portion of a clip 60 and a lanyard 62 that would normally be attached to a safety harness or to a cable attached to a safety harness, are illustrated in FIGS. 1-6.
FIGS. 1-6 show a first embodiment of a safety anchor system in accordance with the present invention. The safety anchor system includes a first embodiment of a force distribution device in accordance with the present invention and generally indicated at 36. Force distribution device 36 further includes a first embodiment of a bearing plate in accordance with the present invention and generally indicated at 38.
FIGS. 7-11 illustrate a second embodiment of a safety anchor system in accordance with the present invention. The safety anchor system includes a second embodiment of a force distribution device in accordance with the present invention and generally indicated at 136. Force distribution device 136 further includes a first embodiment of a bearing plate in accordance with the present invention and generally indicated at 138.
Referring now to FIGS. 1-6, force distribution device 36 is comprised of bearing plate 38 and a cable choke 40. Bearing plate 38 is an L-shaped plated comprised of a first leg 42 and a second leg 44 that are disposed at an angle to each other. The angle is between 80° and 100° and preferably is 90°. Bearing plate 38 is manufactured from a strong, rigid material such as a metal, preferably steel.
First leg 42 is a generally planar member having a first face 42 a and a second face 42 b. First leg 42 defines a pair of spaced-apart apertures 46 therein that extend between first face 42 a and second face 42 b. The planar member may be reinforced in the regions immediately surrounding apertures 46. Second leg 44 is also a generally planar member having a first face 44 a and a second face 44 b.
In accordance with a specific feature of the present invention, first face 44 a is provided with a non-skid surface 48 thereon. When force distribution device 36 is used, second leg 44 of bearing plate 38 is positioned in abutting contact with an upper surface 22 a of one of the rafters 22 of truss 18. Non-skid surface 48 is provided to improve the traction between bearing plate 38 and the upper surface 22 a of truss rafter 22. Non-skid surface 48 may be provided on first face 44 a in a number of ways. Firstly, a plurality of grooves and ridges may be milled into the smooth original metal surface of first face 44 a. Alternatively, a compound such as a gripping polymer may be applied to first face 44 a or an abrasive aggregate may be bonded to the metal of first face 44 a with an adhesive. Any other suitable methodology and substances may be utilized or applied to first face 44 a to produce the non-skid surface 48 and these other methodologies and substances are considered to fall within the scope of the present invention. Additionally, it should be understood that bearing plate 38 may be produced in shapes other than the L-shape illustrated herein without departing from the scope of the present invention provided that the differently configured bearing plate is able to distribute force over a greater area of rafter 22 than would be the case if a cable directly connected the safety harness on the roofer to the rafter.
Preferably, the exterior edges 50 of one or both of first and second legs 42, 44 on bearing plate 38 are beveled or rounded so as to present a curved surface for contact by cable choke 40 and so as to reduce the possibility of bearing plate 38 cutting into the wood of rafter 22 and thereby damaging the same.
Cable choke 40 preferably is a steel cable that is of sufficient strength so as not to break in the event of an impact due to a roofer falling. A free end of the cable 39 of cable choke 40 is threaded into a first one of the apertures 46 in bearing plate 38 in the direction indicated by arrow “A” in FIG. 3. Cable 39 is then threaded through the second one of the apertures 46 in bearing plate 38 from the direction indicated by arrow “B” in the same figure. The free ends of cable 39 are then looped back upon themselves and swages 52 are crimped adjacent these looped regions to secure cable choke 40 in place. Cable choke 40 thus includes a first looped region 54 and a second looped region 56 which are disposed adjacent second face 42 b of first leg 42 of bearing plate 38. A third looped region 58 is created between a portion of cable 39 and first face 42 a of first leg 42. It will be understood that bearing plate 38 is not fixedly secured to cable choke 40 and plate 38 is able to slide along cable 39 thereof. This enables the roofer to adjust the size of third looped region 58 and to correctly position bearing plate 38 on truss 22.
Force distribution device 36 is used in the following manner. A clip 60 secured to a lanyard 62 is engaged with third looped region 58 on force distribution device 36. Although not shown herein, it is to be understood that lanyard 62 may itself be directly connected to a safety harness worn by the roofer or it may be connected to a cable that is secured to the safety harness. Bearing plate 38 is positioned on an upper surface 22 a of an appropriate one of rafters 22. The rafter is selected based on which side of the roof the roofer will be working. Bearing plate 38 should be positioned on the rafter disposed on the opposite side of the roof from the roofer. Non-skid surface 48 of bearing plate 38 is therefore positioned on upper surface 22 a of rafter 22A adjacent peak 28 and in such a way that third looped region 58 is disposed between the roofer and bearing plate 38. Additionally, a first portion of cable 39 and first looped area 54 are positioned adjacent a first side wall of rafter 22A and a second portion of cable 39 and second looped area 56 are positioned adjacent an opposed second side wall of rafter 22A. An anchor plate pin 64 is inserted through one of the holes 34 in anchor plate 26 and the aligned first and second looped areas 54, 56 on cable choke 40. (Pin 64 will be removed when it is desired to disengage force distribution device 36 from rafter 22A.). The roofer secures his safety harness (not shown) to lanyard 62. Non-skid surface 48 on bearing plate 38 aids in substantially immobilizing bearing plate 38 on rafter 22A. Consequently, if the roofer should fall, the impact thereof will be transmitted from the harness (not shown) through lanyard 62 and clip 60 to force distribution device 36. The force is then transmitted through cable choke 40 to bearing plate 38 and is thereby transmitted to a region of rafter 22A in abutting contact with bearing plate 38. The traction of bearing plate 38 on rafter 22A afforded by non-skid surface 48 substantially prevents bearing plate 38 from sliding along rafter 22 under the impact of the force. Bearing plate 38 aids in distributing the force due to the impact more evenly into the upper surface 22 a of rafter 22 and thereby aids in attenuating that force and reducing potential damage to rafter 22 and sheathing 20. Additionally, at least a portion of the steel cable 39 of cable choke 40 is in contact with the metal of bearing plate 38 instead of being in direct contact with the wood of rafter 22A. The metal disposed between cable 39 and the wood of rafter 22A also substantially reduces the potential damage to rafter 22A. As illustrated in FIG. 2, it is desirable that the edge 43 of bearing plate 38 be positioned above or aligned with peak 28 to further reduce the potential for damage to the same.
FIGS. 7-11 show a second embodiment of a force distribution device in accordance with the present invention, generally indicated at 136. Force distribution device 136 is also configured to be engaged with a truss anchor plate 126 mounted on a roof truss 118. As with the previous embodiment, force distribution device 136 comprises a bearing plate 138 and cable choke 140. Cable choke 140 is substantially identical to cable choke 40 and will therefore not be described in further detail.
The features of bearing plate 138 are shown in greater detail in FIGS. 9-11. Bearing plate 138 comprises a generally L-shaped bracket having a first leg 142 and a second leg 144. First and second legs 142, 144 are disposed at an angle relative to each other that is between 80° and 100° and preferably is 90°. Bearing plate 138 is manufactured from a strong, rigid material such as metal, preferably steel.
First leg 142 of bearing plate 138 is a generally planar member having a first face 142 a and a second face 142 b. In accordance with a specific feature of the present invention, first leg 142 is a generally U-shaped member comprising first and second arms 165, 167 that define a gap 166 there between. Gap 166 is sized and shaped to be complementary to the cross-sectional size and shape of at least a top region of a roof rafter 122. First leg 142 defines a first portion 168 a that will abut a first side surface (not shown) of rafter 122 when plate 138 is engaged therewith, a second portion 168 b that will abut an upper surface 122 a of rafter 122, and a third portion 168 c that will abut a second side surface 122 b of rafter 122.
In accordance with yet another feature of the present invention, a pair of tubular conduits 170, 172 is welded or otherwise secured to second face 142 b of bearing plate 138. Tubular conduit 170 is provided on first leg 165 of bearing plate 138 and tubular conduit 172 is provided on second leg 167 thereof. Tubular conduits 170, 172 each define a bore 170 a, 172 a there through that is of any cross-sectional shape suitable to receive a portion of cable 139 of cable choke 140 there through.
Second leg 144 of bearing plate 138 is a generally planar member having a first face 144 a and a second face 144 b. In accordance with the present invention, first face 144 a is provided with a non-skid surface and is adapted to abut upper surface 122 a of truss rafter 122 when force distribution device 136 is engaged therewith. The non-skid surface provided on first face 144 a is shown in FIGS. 7-11 to be a plurality of alternating grooves 174 and ridges 176 that are milled into first face 144 a. The number of such grooves 174 and ridges 176 provided in first face 144 a can vary. Preferably, the entire first face 144 a is provided with grooves 174 and ridges 176 from adjacent first leg 142 to the edge 150 a of second leg 144 as is illustrated in FIG. 11. Preferably, each groove 174 and ridge 176 extends substantially continuously from one side 151 of second leg 144 to the other side 153 thereof as is shown in FIG. 10. It will be understood, however, that regions of smooth metal may be interspersed along the length of each groove 174 and ridge 176 between sides 151, 153 or between adjacent grooves 174 and ridges 176 from first leg 142 to edge 150 a. It will further be understood that the provision of only one or two edges provided by such grooves 174 and ridges 176 will be able to generate sufficient skid-resistance to substantially immobilize bearing plate 136 on upper surface 122 a in the event of a roofer falling. However, the greater the number of edges provided, the better the bearing plate 138 distributes the forces that are generated by the roofer falling and hanging from the anchor safety system. Consequently, an increased number of edges on first face 144 a of bearing plate 136 will tend to lead to better protection of the wood surfaces of truss rafter 122 and sheathing 120 that might otherwise be damaged.
In accordance with yet another feature of the present invention, second leg 144 of bearing plate 136 further includes a pair of spaced apart tubular conduits 178, 180. Tubular conduits 178, 180 are welded or otherwise secured to second face 144 b of bearing plate 138. Tubular conduits 178, 180 each define a bore 178 a, 180 a there through that is configured to have a cross-sectional shape through which cable choke 140 may be threaded. Tubular conduit 178 is generally aligned with tubular conduit 170 and tubular conduit 180 is generally aligned with tubular conduit 172. A first portion of cable 139 is threaded through tubular conduits 172 and 178 in a first direction, and a second portion of cable choke 140 is threaded through tubular conduits 174 and 180 in the opposite direction so that a looped region is formed in cable 139 as was the case with cable choke 40. The free ends of cable 139 are then looped back onto themselves and swages 152 are used to secure the same. Cable choke 140 therefore includes first, second and third looped regions as was the case with cable choke 40, except that in FIG. 7, only second and third looped regions 156 and 158 are shown. Bearing plate 138 is not fixedly secured to cable choke 140 and is able to slide along cable 139 so that the roofer can correctly position bearing plate 138 on rafter 122 and can pull sufficient cable 139 through tubular conduits 172, 174, 178, 180 to create the third looped section 158 of a sufficient size to attach his lanyard (not shown in these figures).
Force distribution device 136 is used in the following manner. Bearing plate 138 is positioned on upper surface 122 a of rafter 122 as illustrated in FIG. 8 so that the top end of the rafter 122 is received in gap 166 in bearing plate 138. Bearing plate 138 is moved downwardly so that second portion 168 b of first leg 142 abuts upper surface 122 a of rafter and the ridges 176 of first face 144 a of second leg 144 contact upper surface 122 a adjacent peak 128. Bearing plate 138 has a longitudinal axis “Y” (FIGS. 9 & 11) that is generally aligned with a longitudinal axis of roof truss rafter 122. An anchor pin 164 is inserted through one of holes 134 on anchor plate 126 and through the aligned first and second looped regions of cable choke 140. This secures force distribution device and truss together. It should be noted that grooves 174 and ridges 176 are milled into first face 144 a of bearing plate 138 in such a manner that they are disposed generally at right angles to longitudinal axis “Y”. Consequently, when bearing plate 138 is positioned on upper surface 122 a, the ridges 176 on first face 144 a of bearing plate 138 are oriented substantially at right angles to the longitudinal axis of rafter 122 and are therefore able to generally immobilize the plate with respect to movement that is substantially directed along the longitudinal axis thereof. Additionally, first and second arms 165, 167 aid in generally reducing any lateral motion of bearing plate 138 in a direction substantially perpendicular to axis “Y”. Once again, force distribution device 136 and particularly bearing plate 138 thereof, helps distribute and attenuate the force exerted on truss rater 122 in the event of a fall by the roofer and thereby aid in preventing truss rafter 122 and sheathing 120 from being damaged.
FIGS. 12 and 13 show a third embodiment of a force distribution device in accordance with the present invention, generally indicated at 236. Force distribution device 236 is also configured to be engaged with a truss anchor plate 226 mounted on a roof truss 218. As with the previous embodiment, force distribution device 236 comprises a bearing plate 238 and cable choke 240. Cable choke 240 is substantially identical to cable choke 40 and will therefore not be described in further detail.
Bearing plate 238 comprises a generally L-shaped bracket having a first leg 242 and a second leg 244. First and second legs 242, 244 are disposed at an angle relative to each other that is between 80° and 100° and preferably is 90°. Bearing plate 238 is manufactured from a strong, rigid material such as metal, preferably steel.
First leg 242 of bearing plate 238 is a generally planar member having a first face 242 a and a second face 242 b. In accordance with a specific feature of the present invention, first leg 242 is a generally U-shaped member comprising first and second arms 265, 267 that define a gap 266 there between. Gap 266 is sized and shaped to be complementary to the cross-sectional size and shape of at least a top region of a roof rafter 222. First leg 242 defines a first portion 268 a that will abut a first side surface (not shown) of rafter 222 when plate 238 is engaged therewith, a second portion 268 b that will abut an upper surface 222 a of rafter 222, and a third portion 268 c that will abut a second side surface 222 b of rafter 222.
In accordance with yet another feature of the present invention, a pair of apertures 290, 292 is defined in first leg 242 of bearing plate 238. Aperture 290 is defined in first arm 265 and aperture 292 is defined in second arm 267. Apertures 290, 292 extend between first and second faces 242 a, 242 b of first leg 242 and preferably are positioned adjacent the region 294 where first leg 242 is joined to second leg 244, i.e., the apertures are positioned close to the corner of bearing plate 238. Preferably, apertures 290, 292 are horizontally aligned with each other.
Second leg 244 of bearing plate 238 is a generally planar member having a first face 244 a and a second face 244 b. In accordance with the present invention, first face 244 a is provided with a non-skid surface and is adapted to abut upper surface 222 a of truss rafter 222 when force distribution device 236 is engaged therewith. The non-skid surface provided on first face 244 a is substantially identical to the non-skid surface provided on first face 144 a of bearing plate 138. As such, the non-skid surface comprises a plurality of alternating grooves 274 and ridges 276 that are milled into first face 244 a. The possible variations in the grooves and ridges have been described with reference to bearing plate 138 and will therefore not be discussed further herein. It should be understood that other suitable non-skid surfaces may be provided on first face 244 a without departing from the scope of the present invention.
In accordance with yet another feature of the present invention, a pair of apertures 296, 298 is defined in second leg 244 of bearing plate 238. Aperture 296 is defined adjacent a first edge 244 c and extends between first and second faces 244 a, 244 b of first leg 244. Aperture 296 is substantially longitudinally aligned with aperture 290 in first leg 242. Aperture 298 is defined adjacent a second edge 244 d of second leg 244 and extends between first and second faces 244 a, 244 b. Aperture 298 is substantially longitudinally aligned with aperture 294 in first leg 242. Aperture 296 is generally horizontally aligned with aperture 298.
A first portion of cable 239 of cable choke 240 is threaded through aligned apertures 290 and 296 in a first direction, and a second portion of cable choke 240 is threaded through aligned apertures 298, 294 in the opposite direction so that a looped region is formed in cable 239 as was the case with cable choke 40. As illustrated in FIG. 12, the direction of threading of cable 239 is such that a portion of the cable 239 runs along second face 242 b of each of the first and second arms 265, 267 and a portion of cable 239 abuts second face 244 b of second leg 244. This ensures that when a force is applied to bearing plate 238, the cable 239 will force plate 238 downwardly into contact with upper surface 222 a of rafter 222. The free ends of cable 239 are looped back onto themselves after being threaded through apertures 290, 296, 298 and 294 and swages 252 are used to secure the same. Cable choke 240 therefore includes first, second and third looped regions as was the case with cable choke 40, except that in FIG. 12, only second and third looped regions 256 and 258 are shown. Bearing plate 238 is not fixedly secured to cable choke 240 and is able to slide along cable 239 so that the roofer can correctly position bearing plate 238 on rafter 222 and can pull sufficient cable 239 through apertures 290, 296, 298, 294 to create the third looped section 258 of a sufficient size to attach his lanyard 260.
Force distribution device 236 is used in the following manner. Bearing plate 238 is positioned on upper surface 222 a of rafter 222 as illustrated in FIG. 12 so that the top end of the rafter 222 is received in gap 266 in bearing plate 238. Bearing plate 238 is moved downwardly so that second portion 268 b of first leg 242 abuts upper surface 222 a of rafter and the ridges 276 of first face 244 a of second leg 244 contact upper surface 222 a adjacent the truss peak (not shown). Bearing plate 238 has a longitudinal axis (not shown) that is generally aligned with a longitudinal axis of roof truss rafter 222. An anchor pin 264 is inserted through one of holes 234 on anchor plate 226 and through the aligned first and second looped regions of cable choke 240. This secures force distribution device and truss together. It should be noted that grooves 274 and ridges 276 are milled into first face 244 a of bearing plate 238 in such a manner that they are disposed generally at right angles to the longitudinal axis of bearing plate 238. Consequently, when bearing plate 238 is positioned on upper surface 222 a, the ridges 276 on first face 244 a are oriented substantially at right angles to the longitudinal axis of rafter 222 and are therefore able to generally immobilize the plate with respect to movement that is substantially directed along the longitudinal axis thereof. Additionally, first and second arms 265, 267 aid in generally reducing any lateral motion of bearing plate 238 in a direction substantially perpendicular to the longitudinal axis. Once again, force distribution device 236 and particularly bearing plate 238 thereof, helps distribute and attenuate the force exerted on truss rater 222 in the event of a fall by the roofer and thereby aid in preventing truss rafter 222 and sheathing 220 from being damaged.
Force distribution device 236 has been found to be adaptable to a range of different roof pitches that might be encountered by a roofer. Device 236 has a lower center of gravity than devices 36 and 136 and therefore tends to hold better on roof trusses having a steeper pitch.
FIGS. 14 and 15, illustrate how the device of the present invention may be used in tandem as a pair to better secure a roofer in certain situations. In this instance a spreader bar 302 is operationally engaged with two or more force distribution devices 236. Bearing plates 238 of devices 236 are engaged on adjacent roof trusses 222. Bar 302 is positioned between two separate riser cable chokes 240 and is attached to each riser cable choke 240 by a suitable fastener 304, thereby incorporating the force resistance capacity of two truss anchor plates (not shown). The safety harness lanyard 260 is secured to bar 302. The connected safety harness lanyard 260 is thereby able to deliver a greater measure of safety to the worker in the event of a fall arrest. The spreader bar 302 can be located directly on the roof ridge or off the roof ridge.
It should be noted that one of the advantages of the present invention is that the force geometry relating to securing a lanyard to a roof anchor has been improved over devices that were previously known. In particular, the force geometry is improved by cabling the resistance from under the rafter to the top of the rafter through the bearing plate. Devices 36, 136 and 236 transfer the energy force from the bottom of truss rafter 22, 122, 222 and anchor plate 26, 126, 226 to the top of truss rafter 222 when an attached roofer slips or falls from the roof. This force passes through the slide adjustable bearing plate 38, 138, 238. The force transfer is important in that it creates a direction of force that favorably compresses the peak truss rafter joint (indicated at 300 in FIG. 12) together, thus strengthening rafter 222 rather than causing a horizontal pulling force on the lower portion of truss anchor plate 226.
In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.
Moreover, the description and illustration of the invention are an example and the invention is not limited to the exact details shown or described.

Claims

1. A force distribution device for securement between a structural member disposed a distance vertically above the ground and a safety harness lanyard worn by a person, said device comprising;

a cable choke adapted to engage the safety harness lanyard; and

a bearing plate engaged with the cable choke and adapted to engage a portion of the structural member; said bearing plate being configured to distribute forces into the structural member that are generated by the weight of the person falling toward the ground.

2. The force distribution device as defined in claim 1, wherein the bearing plate is a bracket having a first leg and a second leg, wherein the first and second legs are disposed at an angle to each other, and wherein the second leg is adapted to abut the structural member.

3. The force distribution device as defined in claim 2, further comprising:

a first face provided on the second leg and adapted to abut the structural member; and

a non-skid surface provided on the first face.

4. The force distribution device as defined in claim 3, wherein the non-skid surface comprises at least one groove or ridge provided on the first face.

5. The force distribution device as defined in claim 4, wherein the bearing plate has a longitudinal axis that is adapted to be aligned with a longitudinal axis of the structural member, and wherein the at least one groove or ridge is disposed substantially at right angles to the longitudinal axis of the bearing plate.

6. The force distribution device as defined in claim 4, wherein the second leg extends outwardly from the first leg and terminates in an edge disposed substantially parallel to the first leg, and a plurality of alternating grooves and ridges are provided in the first face of second leg between the first leg and the edge thereof.

7. The force distribution device as defined in claim 6, wherein the plurality of grooves and ridges cover substantially the entire first face.

8. The force distribution device as defined in claim 4, wherein the second leg extends outwardly from the first leg and terminates in an edge disposed substantially parallel to the first leg, and wherein the second leg further has opposing sides extending between the first leg and the edge, and wherein the at least one groove or ridge extends for at least a partial distance between the opposing sides.

9. The force distribution device as defined in claim 3, wherein the non-skid surface comprises a gripping compound or an abrasive compound applied to the first face of the second leg.

10. The force distribution device as defined in claim 2, further comprising:

a first guide channel provided on the first leg of the bearing plate, and

a cable provided in the cable choke, and wherein a first portion of the cable is received through the first guide channel.

11. The force distribution device as defined in claim 10, wherein the first guide channel comprises one of a first aperture defined in the first leg and a first tubular element disposed on the first leg, where the first aperture extends between a first face and a second face of the first leg, and the first tubular element is disposed on the second face of the first leg and generally parallel to a longitudinal axis of the bearing plate.

12. The force distribution device as defined in claim 10, further comprising:

a second guide channel provided on the first leg of the bearing plate a spaced distance from the first guide channel, and wherein a second portion of the cable is received through the second guide channel.

13. The force distribution device as defined in claim 12, wherein the second guide channel comprises one of a second aperture defined in the first leg and a second tubular element disposed on the first leg, where the second aperture extends between the first face and the second face of the first leg, and the second tubular element is disposed on the second face of the first leg and generally parallel to the longitudinal axis of the bearing plate.

14. The force distribution device as defined in claim 10, further comprising:

a second guide channel provided on the second leg of the bearing plate, said second guide channel being generally aligned with the first guide channel on the first leg, and wherein a second portion of the cable is received through the second guide channel.

15. The force distribution device as defined in claim 14, further comprising:

a third guide channel provided on the first leg of the bearing plate a spaced distance from the first guide channel, and wherein a third portion of the cable is received through the third guide channel; and

a fourth guide channel provided on the second leg of the bearing plate, said fourth guide channel being generally aligned with the third guide channel on the first leg, and wherein a fourth portion of the cable is received through the fourth guide channel.

16. The force distribution device as defined in claim 15, wherein the third guide channel comprises a third aperture defined in the first leg and extending between the first and second faces thereof; and the fourth guide channel comprises a fourth aperture defined in the second leg and extending between the first and second faces thereof.

17. The force distribution device as defined in claim 15, wherein the third guide channel comprises a third tubular element provided on the second face of the first leg and the fourth guide channel comprises a fourth tubular element provided on the second face of the second leg

18. The force distribution device as defined in claim 3, wherein the first leg of the bearing plate further comprises:

a first arm disposed generally at right angles to the second leg of the bearing plate;

a second arm disposed generally at right angles to the second leg of the bearing plate; and

a gap defined between the first and second arms, and wherein the bearing plate is adapted to receive a portion of the structural member in the gap.

19. A safety anchor system for a person comprising:

a harness adapted to be worn on the body of the person;

a force distribution device adapted to engage a structural member disposed a distance vertically above the ground; and

a lanyard extending between the harness and the force distribution device; and wherein the force distribution device comprises:

a cable choke selectively engageable with the lanyard; and a bearing plate engaged with the cable choke and adapted to engage a portion of the structural member; said bearing plate being configured to distribute forces into the structural member that are generated by the weight of the person falling toward the ground.

20. In combination,

a roof truss including a truss rafter, said roof truss being disposed a distance above the ground;

an anchor plate secured to the roof truss;

a harness adapted to be worn on the body of a roofer;

a force distribution device selectively engageable with a portion of the roof truss; said force distribution device comprising:

a cable choke secured to the anchor plate;

a bearing plate engaged with the cable choke and disposed in abutting contact with truss rafter; and

a lanyard extending between the harness and the force distribution device; wherein said bearing plate is configured to distribute forces into the truss rafter that are generated by the roofer falling toward the ground.

21. The combination as defined in claim 20, further comprising a non-skid surface provided on the bearing plate, said non-skid surface resisting movement of the bearing plate along the truss in the event the roofer falls toward the ground.

22. The combination as defined in claim 21, wherein the cable choke and bearing plate transfer a load on the lanyard from the anchor plate to a top region of the truss rafter.