CA2114898A1 - Fall-arrest strap and fall prevention method - Google Patents
Fall-arrest strap and fall prevention methodInfo
- Publication number
- CA2114898A1 CA2114898A1 CA 2114898 CA2114898A CA2114898A1 CA 2114898 A1 CA2114898 A1 CA 2114898A1 CA 2114898 CA2114898 CA 2114898 CA 2114898 A CA2114898 A CA 2114898A CA 2114898 A1 CA2114898 A1 CA 2114898A1
- Authority
- CA
- Canada
- Prior art keywords
- strap
- worker
- fall
- arrest
- flexible
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
- A62B35/00—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion
- A62B35/04—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion incorporating energy absorbing means
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- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Emergency Lowering Means (AREA)
Abstract
A fall-arrest strap for attachment to a safety belt or harness worn by a worker or a tether to a safety belt or harness worn by a worker having one endattached to a support structure and a method for attaching the strap to a woodenbeam. A handle is at the other end of the strap for attaching the strap to the safety belt or harness worn by the worker or the tether secured thereto. Flexible support webbing is attached to the handle. The flexible support webbing has an intermediary folded-over portion secured by stitches. The stitches have less tensile strength than the flexible support webbing whereby when the worker falls, the stitches break upon application of a force less than the breakage strength of the strap, thereby absorbing shock load. The strap possesses at one end thereof attachment means to aid in attaching the strap to the support structure. The fall prevention method to secure workers to a support structure comprises passing securement means, which in the preferred embodiment are nails through one end of a flexible fall arrest strap to thereby attach the end of the strap to a beam or truss, and wrapping the strap at least once around the beam, and securing the other end of the strap to the worker. In this manner, the force exerted by the fallen worker is applied perpendicular to the direction of insertion of the securement means into the flexible strap means.
Description
21:~q.8~8 FALL-ARRESI- SI RAP AND FALL PREVEN~ON MEIHOD
Field of ~e Invention This invention relates to a fall-arrest strap and, more particularly, relates to a fall-arrest strap having an intPrmP~ ry folded-over stitched portion which acts as a shock absorber when the strap is employed, and to a mPthntl for ~tt~rhing the strap to a wooden beam at a workcitP-Ba~u~d of the IllVt~ iUIl Fall-arrest straps used as safety devices to protect workers from risk of injury or death from a fall when working at elevated workcitPs or on uneven or unb~l~nce~l work surfaces are well known.
Fall-arrest straps may be secured to workcitPc at various lor~honc to enable workers to be secure at all times. They may be attached to a safety belt or h~rnPcs around a worker's waist or to a tether ~tt~rh~l to a worker's safety belt or h~rnPcs to secure the worker.
C~n~ n Patent No. 1,182,435 which issued February 12, 1985 to Sulowski et al shows a ladder climbers' safety device which ~tt~rhPs to the climber's safety belt. The device has a pair of handle members which colltain l~trhing means for engaging the rungs of a ladder. The handle members are interconnPctP-l with a climber's safety belt and with one another by a flexible cable. The cable is freely threaded through a co~nPctor ring ~tt~rhP-1 to the climber's safety belt. The support further co.. 'l" ;cec a flP~ihl~ wire rope fastened to the handle members and passing through ~e cr)nnPctor ring. When using the device, the handle members are ~kPrn~tPly moved to engage successive rungs of a ladder. rn the event of a fall, the wire rope absorbs the shock load.
C~n~ n Patent No. 1,182,435 relates to a safety device which utilizes a wire rope for absorbing the shock load of a fall rather than the interconnPchng fle~nble cable.
Su~ of the Invention The disadvantages of the prior art may be ov~:rcol~e by providing a relatively light weight fall-arrest strap which itself su~L~ S a large amount of force and provides a means for re~llleing the amount of force initially felt by a fallen worker.
Accorlingly, in one broad aspect, the fall-arrest strap of the present invention comprises:
~tt~rhmPnt means at one end thereof to allow ~tt~hmPnt to a support structure;
handle means at the other end of said strap for attaching said strap to the safety belt or h~rnP~s worn by the worker or a tether secured thereto;
fl~rihle support means intPrmP~i~te said handle me~ns and said atta~hmPnt means, said fle~ible support means having an intPrmPrli~ry folded-over portion secured by stitches, said sht~hPs having less tensile strength than saidflexible support means, whereby when the worker falls, said stitches break upon application of a force less than the breakage strength of said strap, thereby absorbing shock load. The fall-arrest strap may be used to secure a worker working at elevated job sites or may be used to st~hili7e such structures as l~ldPr~ from lateral movement.
Accur~ g to another embo-Iim~nt of the invention, the flexible support means interconnPcting said ~tt~rhmPnt means with said handle means and 211~8Q ~'~
~tt~chmPnt means has an int~rmP~i~ry folded-over portion which has a plurality of folds secured by stitches, said stitches having less tensile strength than said fle~nble support mP~n~, whereby when the worker falls, said stitches break upon application of a force less than the breakage strength of said strap, thereby absorbing shock load.
In a further preferred embo~limPnt, the ~tt~rhmPnt means simply comprises a portion of strap that is of a weave sl-ffl~iPntly fl~ihle or porous enough to allow nails to be h~mmPred or inserted the,elh~ough, to allow one end of the strap to be nailed to a wooden beam. ~ltprn~tply~ such ~tt~chm~nt means at said one end of the strap may con,~l;se ferrules located within said strap, to allow nails to be inserted thel~ough to allow said one end of strap to be secured to a wooden beam.
The invention also relates to a fall prevention method to secure workers to a support structure, c-)mpri~ing:
p~Csing se~ur~llent means, which in the plert:lled embodiment are nails, through one end of a fl~ihle fall arrest strap to thereby attach one end of said strap to a wooden beam or truss, sd wrapping said strap at least once around said beam and securing said other end of said strap to said worker.
Advantageously, the above method of attaching a fall arrest strap to a wooden beam allows easy and rapid securement of the strap to a beam and by wrapping the strap at least once around the beam allows any force on the strap and nails to be applied perpendicularly to the direction of insertion of the nails in the beam. By having the force exerted perpendicular to the direction of insertion ofnails into the beam, a greater cross-section of strap m~tPri~l is able to resist the 21~4~g8 applied force than would otherwise be the case if there was no wrapping of the strap about the beam and any applied force was thus applied in an axial direction (i.e. in a direction parallel to the direction of insertion of the nails), in which case the entire force is only resisted by the portion of the strap underlying the head of the inserted nails.
Brief Description of the Drawings The present invention will now be described in detail with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of a worksite with devices of the invention secured at various positions at the worksite and a workman attached to a tether which is attached to the fall-arrest strap of the invention.
Figure 2 is a perspective view of the strap of the present invention.
Figure 3 is a perspective view of the strap of the present invention.
Figures 4 and 5 are fr~gmPnt~ry perspective views illustrating two embollimPn~ of the anchor bracket of the strap of the invention.
Figure 6 is a fr~gmPnt~ry side elevation view of another embodiment of the anchor bracket of the strap of the invention.
Figure 7 is a perspective view of the embodiment of the strap shown in Figure 6.
Figure 8 is a side view of the strap of the invention attached to a wood beam.
Des~ ion of the Prefem~d Embodimf~n~
Referring first to Figure 1, the fall-arrest strap 12 of the present invention may be placed at numerous positions around worksite 10 or support 21~L4~
structures such as walls, etc. Strap 12iS~tt~chptl to tether 14 which is ~tt~rhPti to safety belt 16 worn by worker 11. Strap 12 may also be ~tt~rhPrl dir~.lly to safety belt 16. Worker 11 may move about wo~ e 10 by simply securing tether 14 to a strap 12 which is closest to the position of worker 11 at worksite 10. Tether 14 may be of different lengths and it, in comhin~tion with the various pl~cPmPntc of straps 12 about worksite 10, Pn~hlPc worker 11 to be secure at all times. Worker11 may wear a h~rnPss in place of safety belt 16 for attarhmPnt to tether 14 or for hmPnt di~ ;Lly to strap 12.
Figure 2 shows strap 12 in detail. Strap 12isplt:rE:ldbly a flP~riblP
m~tPri~l, such as nylon webbing, having one end where nails may be h~mmPred thele:lhLough, and has D-ring 18 which attaches to safety belt 16 or a h~rnPss worn by worker 11. Anchor bracket 20is located at the other end of strap 12. Anchor bracket 20 has aperture 24 formed therein. Loops 26 are formed at both ends of strap 12 and are stitched in place by collvelllional thread. Loops 26 are formedaround D-ring 18 or similar handle members and anchor bracket 20, to allow the flexible strap to be aff~xed to Ring 18 and bracket 20. A nail or a bolt and nutcombination is placed through aperture 24 to join strap 12 to a truss at a work~ite.
In a preferred embo-limPnt, anchor bracket 20is not llhli7P~, and the strap 12 at one end thereof is of a weave sllmriPntly flexible to allow nails to be h~mmPred th~LLough to attach one end of strap 12 to a wooden beam or truss.
rmpolL~lLly, the nylon webbing of strap 12 has an intPrmP~
folded-over portion 22. The folded-over portion 22 of strap 12is stitched in place with collv~lLion thread similar to the stitching forrr~ing loops 26. The stitches have less tensile strength than the nylon webbing. When a worker falls, stitches of 2114~9~
folded-over portion 22 break, thereby abso.l,i-~g shock load. The amount of force initially felt by the worker is, therefore, reduced, to lessen the lik.qliht~od of injury to a falling worker.
Figure 3 illustrates an ~mho~im~nt of strap 12 wherein the webbing has been folded to give a plurality of folded-over portions 22. The folds are stitched in place with col.v~l~ional thread. The stitches have less tensile strength than the nylon webbing. When a worker falls, the stitches of the two folds succe~ivt:ly break, thereby absorbing shock load and providing a gradual "braking" to the fall of the worker. Stitches are placed through each of the folds and ~l(lit~on~l stitches of thread are used to join the first fold of the webbing to the second fold, etc. The shock load may then be absorbed in a two or more step fashion.
Figures 4, 5 and 6 illustrate further embo~lim.ont~ of anchor brackets for secllring strap 12 to a workcite.
~n Figure 4, the anchor bracket is metal ring 28 which is large enough to be placed over the top of a pole. Since most poles are tapered, ring 28 wouldform a frictio~ fit, thus securing strap 12 in place.
~n Figure 5, the ~tt~rhmPnt means of the strap at one end thereof is a plate 30, having a number of apertures therein. Plate 30 may then be ~ rh~tl to a beam at a worksite by il~ ing fasteners, such as nails, screws, or bolts, through the apertures to secure such end to a structure. ~lt~ hvely~ the web maybe provided with ferrules (not shown) to allow nails, screws, or bolts to be inserted the~ ough to allow the strap 12 at its one end to be secured to a beam or truss,with the other end of the strap having secured to the worker's safety h~rn~s or belt via D-ring 18.
2114~398 In Figure 6, the anchor bracket is split-ring clamp 32 which allows strap 12 to be ~tt~rhP~l to such structures as pipe 40. F~tPncion 44 of strap 12 is welded to clamping member 34 and is Pnr~ce-l by clasp 42. Clamping member 36 is pivotally ~tt~rhP~l to rl~mping member 34 by pin 38. Pin 38 allows for articulation of rl~mping member 36 around pipe 40. ln operation, clasp 42 is spring loaded and is slidably moved towards strap 12, thus, allowing clamping member 36 to be pivoted away from rl~mping member 34. Clamping member 36 is then placed around pipe 40. ~l~mping member 36 is returned to its at-rest position as shown in Figure 6 and clasp 40 is moved towards strap 12. Clasp 40 clasps clamping members 34 and 36 together, thus ~tt~hing strap 12 to pipe 40.
The method of the invention for ~tt~rhing a fall-arrest strap to a wooden beam is illustrated in Figure 8. Strap 12 for l1hli7.~hon in accordance with this method does not have an anchor bracket 20. lnstead, nails or screws 48 secure strap 12 at one end thereof to a wooden beam or truss 46. Nails 48 are either driven through the nylon webbing, or through ferrules in the webbing located at one end thereof. Strap 12 is preferably wrapped one or more times around a 2" x 4" or 2" x 6" piece of wood 44. Nails 50 may further then be driven through bothlayers of webbing. By Wld~illg strap 12 to wood 44, strap 12 is ripped perpendicular to the pull of strap 12 when a worker falls.
The following tensile shrength test examples are included to further illushrate the invention herein described and rl~imPtl The examples are not int~n~le~ as limit~hons of the present invention.
The sample shraps tested were 2" wide x 3/8" thick nylon webbing with a 2l/2" wide D-ring. The D-ring was attached to the strap by a stitched loop 211~g formed on the webbing. The other end of the strap was overlapped and stitched forming a double layer of webbing and this end was nailed to a 2" x 4' or a 2" x 6"
spruce board with 3" ARDOX~ nails. ~n ~Y~mple 7, a pine board was used.
Example 1 The first strap was wrapped once around two 2" x 6" boards. Two ARDOX~ nails were used to fasten the strap to the boards. A third nail was used to fasten the end of the first loop to the boards. The load was applied parallel to the 6" face.
Example 2 The second strap was wrapped one and a half times around one 2" by 6" board. Two ARDOX~ nails were used to fasten the strap to the board; the protruding ends of the nails were bent over. A third nail was used to fasten the end of the first loop to the board and the protruding end of the nail was bent over. The load was applied parallel to the 6" face.
Example 3 The third strap was wrapped one and a quarter times around two 2"
by 4" boards. Two ARDOX~ nails were used to fasten the strap to the wood. Two nails were used to fasten the end of the first loop to the wood. The load was applied parallel to the 2" edges.
Example 4 The fourth strap was wrapped one and a half times around one 2" by 6" board. Two ARDOX~ nails were used to fasten the strap to the wood. The protruding ends of the nails were bent over. A third nail was used to fasten the end 2 1 ~ 8 g of the first loop to the wood and the protruding end of the nail was bent over. The load was applied parallel to the 6" face.
Example 5 The fifth strap was wrapped one and a half times around one 2" by 4" board. Two ARDOX~ nails were used to fasten the strap to the board. The protruding ends of the nails were bent over. A third nail was used to fasten the end of the first loop to the wood and the protruding end of the nail was bent over. The load was applied parallel to the 4" face.
Example 6 The sixth strap was wrapped one time around one 2" by 4" board.
Two ARDOX~ nails were used to fasten the strap to the wood and the protruding end of the nails were bent over. A third nail was used to fasten the end of the first loop to the wood and the protruding end of the nail was bent over. The load was applied parallel to the 4" face.
Example 7 The seventh strap was wrapped once around one 2" by 6" pine board.
Two ARDOX~ nails were used to fasten the strap to the wood. A third nail was used to fasten the end of the first loop to the wood. The load was applied parallel to the 6" face.
The results are shown in the following table:
Number of M;.x;......... Failure Example Loops Applied Load Mode (lbf) 1 1 2,750 Nail heads pulled through webbing 2 ll/z 3,830 "D" ring stitching 211~9~
failed 3 ll/4 3,150 Wood crushed, and webbing failed 4 ll/2 3,500 "D" ring stitching failed ll/2 3,640 Wood crushed, and fractured 6 1 3,280 Wood crushed 7 1 3,380 Webbingfailed at nail hole The prese~lt invention provides a mlmh~r of important advantages.
The fall-arrest strap permits workers to move freely along elevated surfaces and to be secure at all times. The use of an int~rm~ ry folded-over portion in the strap as a means for absorbing shock load obviates the need for a second cable to be used for that purpose.
Although the disclosure describes and illustrates plef~,ed embo-lim~ntc of the invention, many variations and mo~lific~tions will now occurto those skilled in the art. For a full tl~finifiion of the invention, refelellce is to be made to the appended claims.
Field of ~e Invention This invention relates to a fall-arrest strap and, more particularly, relates to a fall-arrest strap having an intPrmP~ ry folded-over stitched portion which acts as a shock absorber when the strap is employed, and to a mPthntl for ~tt~rhing the strap to a wooden beam at a workcitP-Ba~u~d of the IllVt~ iUIl Fall-arrest straps used as safety devices to protect workers from risk of injury or death from a fall when working at elevated workcitPs or on uneven or unb~l~nce~l work surfaces are well known.
Fall-arrest straps may be secured to workcitPc at various lor~honc to enable workers to be secure at all times. They may be attached to a safety belt or h~rnPcs around a worker's waist or to a tether ~tt~rh~l to a worker's safety belt or h~rnPcs to secure the worker.
C~n~ n Patent No. 1,182,435 which issued February 12, 1985 to Sulowski et al shows a ladder climbers' safety device which ~tt~rhPs to the climber's safety belt. The device has a pair of handle members which colltain l~trhing means for engaging the rungs of a ladder. The handle members are interconnPctP-l with a climber's safety belt and with one another by a flexible cable. The cable is freely threaded through a co~nPctor ring ~tt~rhP-1 to the climber's safety belt. The support further co.. 'l" ;cec a flP~ihl~ wire rope fastened to the handle members and passing through ~e cr)nnPctor ring. When using the device, the handle members are ~kPrn~tPly moved to engage successive rungs of a ladder. rn the event of a fall, the wire rope absorbs the shock load.
C~n~ n Patent No. 1,182,435 relates to a safety device which utilizes a wire rope for absorbing the shock load of a fall rather than the interconnPchng fle~nble cable.
Su~ of the Invention The disadvantages of the prior art may be ov~:rcol~e by providing a relatively light weight fall-arrest strap which itself su~L~ S a large amount of force and provides a means for re~llleing the amount of force initially felt by a fallen worker.
Accorlingly, in one broad aspect, the fall-arrest strap of the present invention comprises:
~tt~rhmPnt means at one end thereof to allow ~tt~hmPnt to a support structure;
handle means at the other end of said strap for attaching said strap to the safety belt or h~rnP~s worn by the worker or a tether secured thereto;
fl~rihle support means intPrmP~i~te said handle me~ns and said atta~hmPnt means, said fle~ible support means having an intPrmPrli~ry folded-over portion secured by stitches, said sht~hPs having less tensile strength than saidflexible support means, whereby when the worker falls, said stitches break upon application of a force less than the breakage strength of said strap, thereby absorbing shock load. The fall-arrest strap may be used to secure a worker working at elevated job sites or may be used to st~hili7e such structures as l~ldPr~ from lateral movement.
Accur~ g to another embo-Iim~nt of the invention, the flexible support means interconnPcting said ~tt~rhmPnt means with said handle means and 211~8Q ~'~
~tt~chmPnt means has an int~rmP~i~ry folded-over portion which has a plurality of folds secured by stitches, said stitches having less tensile strength than said fle~nble support mP~n~, whereby when the worker falls, said stitches break upon application of a force less than the breakage strength of said strap, thereby absorbing shock load.
In a further preferred embo~limPnt, the ~tt~rhmPnt means simply comprises a portion of strap that is of a weave sl-ffl~iPntly fl~ihle or porous enough to allow nails to be h~mmPred or inserted the,elh~ough, to allow one end of the strap to be nailed to a wooden beam. ~ltprn~tply~ such ~tt~chm~nt means at said one end of the strap may con,~l;se ferrules located within said strap, to allow nails to be inserted thel~ough to allow said one end of strap to be secured to a wooden beam.
The invention also relates to a fall prevention method to secure workers to a support structure, c-)mpri~ing:
p~Csing se~ur~llent means, which in the plert:lled embodiment are nails, through one end of a fl~ihle fall arrest strap to thereby attach one end of said strap to a wooden beam or truss, sd wrapping said strap at least once around said beam and securing said other end of said strap to said worker.
Advantageously, the above method of attaching a fall arrest strap to a wooden beam allows easy and rapid securement of the strap to a beam and by wrapping the strap at least once around the beam allows any force on the strap and nails to be applied perpendicularly to the direction of insertion of the nails in the beam. By having the force exerted perpendicular to the direction of insertion ofnails into the beam, a greater cross-section of strap m~tPri~l is able to resist the 21~4~g8 applied force than would otherwise be the case if there was no wrapping of the strap about the beam and any applied force was thus applied in an axial direction (i.e. in a direction parallel to the direction of insertion of the nails), in which case the entire force is only resisted by the portion of the strap underlying the head of the inserted nails.
Brief Description of the Drawings The present invention will now be described in detail with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of a worksite with devices of the invention secured at various positions at the worksite and a workman attached to a tether which is attached to the fall-arrest strap of the invention.
Figure 2 is a perspective view of the strap of the present invention.
Figure 3 is a perspective view of the strap of the present invention.
Figures 4 and 5 are fr~gmPnt~ry perspective views illustrating two embollimPn~ of the anchor bracket of the strap of the invention.
Figure 6 is a fr~gmPnt~ry side elevation view of another embodiment of the anchor bracket of the strap of the invention.
Figure 7 is a perspective view of the embodiment of the strap shown in Figure 6.
Figure 8 is a side view of the strap of the invention attached to a wood beam.
Des~ ion of the Prefem~d Embodimf~n~
Referring first to Figure 1, the fall-arrest strap 12 of the present invention may be placed at numerous positions around worksite 10 or support 21~L4~
structures such as walls, etc. Strap 12iS~tt~chptl to tether 14 which is ~tt~rhPti to safety belt 16 worn by worker 11. Strap 12 may also be ~tt~rhPrl dir~.lly to safety belt 16. Worker 11 may move about wo~ e 10 by simply securing tether 14 to a strap 12 which is closest to the position of worker 11 at worksite 10. Tether 14 may be of different lengths and it, in comhin~tion with the various pl~cPmPntc of straps 12 about worksite 10, Pn~hlPc worker 11 to be secure at all times. Worker11 may wear a h~rnPss in place of safety belt 16 for attarhmPnt to tether 14 or for hmPnt di~ ;Lly to strap 12.
Figure 2 shows strap 12 in detail. Strap 12isplt:rE:ldbly a flP~riblP
m~tPri~l, such as nylon webbing, having one end where nails may be h~mmPred thele:lhLough, and has D-ring 18 which attaches to safety belt 16 or a h~rnPss worn by worker 11. Anchor bracket 20is located at the other end of strap 12. Anchor bracket 20 has aperture 24 formed therein. Loops 26 are formed at both ends of strap 12 and are stitched in place by collvelllional thread. Loops 26 are formedaround D-ring 18 or similar handle members and anchor bracket 20, to allow the flexible strap to be aff~xed to Ring 18 and bracket 20. A nail or a bolt and nutcombination is placed through aperture 24 to join strap 12 to a truss at a work~ite.
In a preferred embo-limPnt, anchor bracket 20is not llhli7P~, and the strap 12 at one end thereof is of a weave sllmriPntly flexible to allow nails to be h~mmPred th~LLough to attach one end of strap 12 to a wooden beam or truss.
rmpolL~lLly, the nylon webbing of strap 12 has an intPrmP~
folded-over portion 22. The folded-over portion 22 of strap 12is stitched in place with collv~lLion thread similar to the stitching forrr~ing loops 26. The stitches have less tensile strength than the nylon webbing. When a worker falls, stitches of 2114~9~
folded-over portion 22 break, thereby abso.l,i-~g shock load. The amount of force initially felt by the worker is, therefore, reduced, to lessen the lik.qliht~od of injury to a falling worker.
Figure 3 illustrates an ~mho~im~nt of strap 12 wherein the webbing has been folded to give a plurality of folded-over portions 22. The folds are stitched in place with col.v~l~ional thread. The stitches have less tensile strength than the nylon webbing. When a worker falls, the stitches of the two folds succe~ivt:ly break, thereby absorbing shock load and providing a gradual "braking" to the fall of the worker. Stitches are placed through each of the folds and ~l(lit~on~l stitches of thread are used to join the first fold of the webbing to the second fold, etc. The shock load may then be absorbed in a two or more step fashion.
Figures 4, 5 and 6 illustrate further embo~lim.ont~ of anchor brackets for secllring strap 12 to a workcite.
~n Figure 4, the anchor bracket is metal ring 28 which is large enough to be placed over the top of a pole. Since most poles are tapered, ring 28 wouldform a frictio~ fit, thus securing strap 12 in place.
~n Figure 5, the ~tt~rhmPnt means of the strap at one end thereof is a plate 30, having a number of apertures therein. Plate 30 may then be ~ rh~tl to a beam at a worksite by il~ ing fasteners, such as nails, screws, or bolts, through the apertures to secure such end to a structure. ~lt~ hvely~ the web maybe provided with ferrules (not shown) to allow nails, screws, or bolts to be inserted the~ ough to allow the strap 12 at its one end to be secured to a beam or truss,with the other end of the strap having secured to the worker's safety h~rn~s or belt via D-ring 18.
2114~398 In Figure 6, the anchor bracket is split-ring clamp 32 which allows strap 12 to be ~tt~rhP~l to such structures as pipe 40. F~tPncion 44 of strap 12 is welded to clamping member 34 and is Pnr~ce-l by clasp 42. Clamping member 36 is pivotally ~tt~rhP~l to rl~mping member 34 by pin 38. Pin 38 allows for articulation of rl~mping member 36 around pipe 40. ln operation, clasp 42 is spring loaded and is slidably moved towards strap 12, thus, allowing clamping member 36 to be pivoted away from rl~mping member 34. Clamping member 36 is then placed around pipe 40. ~l~mping member 36 is returned to its at-rest position as shown in Figure 6 and clasp 40 is moved towards strap 12. Clasp 40 clasps clamping members 34 and 36 together, thus ~tt~hing strap 12 to pipe 40.
The method of the invention for ~tt~rhing a fall-arrest strap to a wooden beam is illustrated in Figure 8. Strap 12 for l1hli7.~hon in accordance with this method does not have an anchor bracket 20. lnstead, nails or screws 48 secure strap 12 at one end thereof to a wooden beam or truss 46. Nails 48 are either driven through the nylon webbing, or through ferrules in the webbing located at one end thereof. Strap 12 is preferably wrapped one or more times around a 2" x 4" or 2" x 6" piece of wood 44. Nails 50 may further then be driven through bothlayers of webbing. By Wld~illg strap 12 to wood 44, strap 12 is ripped perpendicular to the pull of strap 12 when a worker falls.
The following tensile shrength test examples are included to further illushrate the invention herein described and rl~imPtl The examples are not int~n~le~ as limit~hons of the present invention.
The sample shraps tested were 2" wide x 3/8" thick nylon webbing with a 2l/2" wide D-ring. The D-ring was attached to the strap by a stitched loop 211~g formed on the webbing. The other end of the strap was overlapped and stitched forming a double layer of webbing and this end was nailed to a 2" x 4' or a 2" x 6"
spruce board with 3" ARDOX~ nails. ~n ~Y~mple 7, a pine board was used.
Example 1 The first strap was wrapped once around two 2" x 6" boards. Two ARDOX~ nails were used to fasten the strap to the boards. A third nail was used to fasten the end of the first loop to the boards. The load was applied parallel to the 6" face.
Example 2 The second strap was wrapped one and a half times around one 2" by 6" board. Two ARDOX~ nails were used to fasten the strap to the board; the protruding ends of the nails were bent over. A third nail was used to fasten the end of the first loop to the board and the protruding end of the nail was bent over. The load was applied parallel to the 6" face.
Example 3 The third strap was wrapped one and a quarter times around two 2"
by 4" boards. Two ARDOX~ nails were used to fasten the strap to the wood. Two nails were used to fasten the end of the first loop to the wood. The load was applied parallel to the 2" edges.
Example 4 The fourth strap was wrapped one and a half times around one 2" by 6" board. Two ARDOX~ nails were used to fasten the strap to the wood. The protruding ends of the nails were bent over. A third nail was used to fasten the end 2 1 ~ 8 g of the first loop to the wood and the protruding end of the nail was bent over. The load was applied parallel to the 6" face.
Example 5 The fifth strap was wrapped one and a half times around one 2" by 4" board. Two ARDOX~ nails were used to fasten the strap to the board. The protruding ends of the nails were bent over. A third nail was used to fasten the end of the first loop to the wood and the protruding end of the nail was bent over. The load was applied parallel to the 4" face.
Example 6 The sixth strap was wrapped one time around one 2" by 4" board.
Two ARDOX~ nails were used to fasten the strap to the wood and the protruding end of the nails were bent over. A third nail was used to fasten the end of the first loop to the wood and the protruding end of the nail was bent over. The load was applied parallel to the 4" face.
Example 7 The seventh strap was wrapped once around one 2" by 6" pine board.
Two ARDOX~ nails were used to fasten the strap to the wood. A third nail was used to fasten the end of the first loop to the wood. The load was applied parallel to the 6" face.
The results are shown in the following table:
Number of M;.x;......... Failure Example Loops Applied Load Mode (lbf) 1 1 2,750 Nail heads pulled through webbing 2 ll/z 3,830 "D" ring stitching 211~9~
failed 3 ll/4 3,150 Wood crushed, and webbing failed 4 ll/2 3,500 "D" ring stitching failed ll/2 3,640 Wood crushed, and fractured 6 1 3,280 Wood crushed 7 1 3,380 Webbingfailed at nail hole The prese~lt invention provides a mlmh~r of important advantages.
The fall-arrest strap permits workers to move freely along elevated surfaces and to be secure at all times. The use of an int~rm~ ry folded-over portion in the strap as a means for absorbing shock load obviates the need for a second cable to be used for that purpose.
Although the disclosure describes and illustrates plef~,ed embo-lim~ntc of the invention, many variations and mo~lific~tions will now occurto those skilled in the art. For a full tl~finifiion of the invention, refelellce is to be made to the appended claims.
Claims (9)
1. A fall-arrest strap, comprising:
attachment means at one end thereof to allow attachment to a support structure;
handle means at the other end of said strap for attaching said strap to the safety belt or harness worn by the worker, or a tether secured to the worker;
flexible support means attached to said handle means, said flexible support means having an intermediary folded-over portion secured by stitches, said stitches having less tensile strength than said flexible support means, whereby when the worker falls, said stitches break upon application of a force less than the breakage strength of said strap, thereby absorbing shock load of said falling worker.
attachment means at one end thereof to allow attachment to a support structure;
handle means at the other end of said strap for attaching said strap to the safety belt or harness worn by the worker, or a tether secured to the worker;
flexible support means attached to said handle means, said flexible support means having an intermediary folded-over portion secured by stitches, said stitches having less tensile strength than said flexible support means, whereby when the worker falls, said stitches break upon application of a force less than the breakage strength of said strap, thereby absorbing shock load of said falling worker.
2. A fall-arrest strap as claimed in claim 1 wherein said handle attachment means comprises a flexible woven strap of a sufficiently flexible weave to allow nails or screws to be inserted therethrough at an end thereof opposite to said handle means to allow securement of said strap to a support structure.
3. A fall-arrest strap as claimed in claim 1 wherein said attachment means comprises ferrules placed in said strap at an end opposite said handle means, wherein nails, screws, or bolts may be inserted therethrough to allow strap at said end opposite said handle means to be secured to a support structure.
4. A fall-arrest strap as claimed in claim 1 wherein said attachment means comprises a bracket and at least one nail or a bolt and nut combination for attaching said bracket to the support structure.
5. A fall-arrest strap as claimed in claim 1 wherein said anchor means isa circular metal ring.
6. A fall-arrest strap as claimed in claims 1, 2, 3, 4 or 5 wherein said flexible support means is nylon webbing.
7. A fall-arrest strap for attachment to a safety belt or harness worn bya worker or a tether to a safety belt or harness worn by a worker comprising:
attachment means at one end of said strap for anchoring said strap to a support structure;
handle means at the other end of said strap for attaching said strap to the safety belt or harness worn by the worker or the tether secured thereto;
flexible support means interconnecting said anchor means with said handle means; said flexible support means having an intermediary portion comprising a plurality of folds secured by stitches, said stitches having less tensile strength than said flexible support means, whereby when the worker falls, said stitches break upon application of a force less than the breakage strength of said strap, thereby absorbing shock load of said falling worker.
attachment means at one end of said strap for anchoring said strap to a support structure;
handle means at the other end of said strap for attaching said strap to the safety belt or harness worn by the worker or the tether secured thereto;
flexible support means interconnecting said anchor means with said handle means; said flexible support means having an intermediary portion comprising a plurality of folds secured by stitches, said stitches having less tensile strength than said flexible support means, whereby when the worker falls, said stitches break upon application of a force less than the breakage strength of said strap, thereby absorbing shock load of said falling worker.
8. A fall prevention method to secure workers to a support structure, comprising:
passing securement means through one end of a flexible fall arrest strap to thereby attach said end of said strap to a beam or truss, and wrapping said strap at least once around said beam, and securing said other end of said strap to said worker.
passing securement means through one end of a flexible fall arrest strap to thereby attach said end of said strap to a beam or truss, and wrapping said strap at least once around said beam, and securing said other end of said strap to said worker.
9. A fall prevention method as claimed in claim 8, wherein passing securement means through said end comprises hammering nails through said flexible strap to secure said one end to said beam or truss, wherein said beam or truss is of wood.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2114898 CA2114898A1 (en) | 1994-02-03 | 1994-02-03 | Fall-arrest strap and fall prevention method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2114898 CA2114898A1 (en) | 1994-02-03 | 1994-02-03 | Fall-arrest strap and fall prevention method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2114898A1 true CA2114898A1 (en) | 1995-08-04 |
Family
ID=4152849
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2114898 Abandoned CA2114898A1 (en) | 1994-02-03 | 1994-02-03 | Fall-arrest strap and fall prevention method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2114898A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005105217A1 (en) * | 2004-04-28 | 2005-11-10 | Mine Safety Appliances Company | Devices, systems and methods for emergency descent from a height |
| FR2905052A1 (en) * | 2006-08-25 | 2008-02-29 | Angelique Elbaz | Safety clothing for preventing access to e.g. genital zone and sub dorsal region of human body, has locking or unlocking device operable by system of carrier or person notified by carrier, and rupture zone made of less resistance material |
| ES2292336A1 (en) * | 2006-02-06 | 2008-03-01 | Nicolas Soler Saez | Security fastening for preventing height falls, particularly building construction, is constituted in center body, which is consist of high-strength tape, where ends of body form respective closed loops |
| FR3030286A1 (en) * | 2014-12-22 | 2016-06-24 | Zedel | TIRE STRAP |
| GR20150100497A (en) * | 2015-11-13 | 2017-08-04 | Παυλος Δημητριου Γιαννακοπουλος | Energy absorption element meant for the smooth fall of workers |
| GB2559038A (en) * | 2016-12-06 | 2018-07-25 | Treemagineers Ltd | Harnesses |
-
1994
- 1994-02-03 CA CA 2114898 patent/CA2114898A1/en not_active Abandoned
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005105217A1 (en) * | 2004-04-28 | 2005-11-10 | Mine Safety Appliances Company | Devices, systems and methods for emergency descent from a height |
| CN1976740B (en) * | 2004-04-28 | 2011-05-18 | 矿井安全装置公司 | Devices, systems and methods for emergency descent from a height |
| ES2292336A1 (en) * | 2006-02-06 | 2008-03-01 | Nicolas Soler Saez | Security fastening for preventing height falls, particularly building construction, is constituted in center body, which is consist of high-strength tape, where ends of body form respective closed loops |
| ES2300210A1 (en) * | 2006-02-06 | 2008-06-01 | Nicolas Soler Saez | Security fastening for preventing height falls, particularly building construction, is constituted in center body, which is consist of high-strength tape, where ends of body form respective closed loops |
| ES2324759A1 (en) * | 2006-02-06 | 2009-08-13 | Nicolas Soler Saez | Security fastening for preventing height falls, particularly building construction, is constituted in center body, which is consist of high-strength tape, where ends of body form respective closed loops |
| FR2905052A1 (en) * | 2006-08-25 | 2008-02-29 | Angelique Elbaz | Safety clothing for preventing access to e.g. genital zone and sub dorsal region of human body, has locking or unlocking device operable by system of carrier or person notified by carrier, and rupture zone made of less resistance material |
| FR3030286A1 (en) * | 2014-12-22 | 2016-06-24 | Zedel | TIRE STRAP |
| WO2016102812A1 (en) * | 2014-12-22 | 2016-06-30 | Zedel | Tear strap |
| GR20150100497A (en) * | 2015-11-13 | 2017-08-04 | Παυλος Δημητριου Γιαννακοπουλος | Energy absorption element meant for the smooth fall of workers |
| GB2559038A (en) * | 2016-12-06 | 2018-07-25 | Treemagineers Ltd | Harnesses |
| GB2559038B (en) * | 2016-12-06 | 2020-02-05 | Treemagineers Ltd | A harness with an energy dissipation region |
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| Date | Code | Title | Description |
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| FZDE | Dead |