CA2131405A1 - Apparatus and method for securing an object against gale force winds - Google Patents
Apparatus and method for securing an object against gale force windsInfo
- Publication number
- CA2131405A1 CA2131405A1 CA002131405A CA2131405A CA2131405A1 CA 2131405 A1 CA2131405 A1 CA 2131405A1 CA 002131405 A CA002131405 A CA 002131405A CA 2131405 A CA2131405 A CA 2131405A CA 2131405 A1 CA2131405 A1 CA 2131405A1
- Authority
- CA
- Canada
- Prior art keywords
- home
- net
- gale
- anchoring
- shielding
- 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
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H9/00—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate
- E04H9/14—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate against other dangerous influences, e.g. tornadoes, floods
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/74—Means for anchoring structural elements or bulkheads
- E02D5/80—Ground anchors
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
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- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Emergency Management (AREA)
- Environmental & Geological Engineering (AREA)
- Business, Economics & Management (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- General Engineering & Computer Science (AREA)
- Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
Abstract
Method for shielding, anchoring and containing an object such as a trailer or motor home in gale-force winds. A wind-permeable perforate sheet extends downwardly and outwardly from the top of the object or the roof of a home at an acute angle so as to surround a substantial portion of each of the sides with an inclined wind-permeable planar surface. The sheet is anchored to helicalground anchors via mechanical attachments which may also be used to tighten the sheet over the object or home. Apparatus for shielding, anchoring and containingan object such as a trailer or motor home in gale-force winds is also disclosed.
Description
2131~05 OBJECT AGAINST GALE-FORCE WINDS
Field of Invention The present invention relates to an appa,dlus and a method for securing objects, particularly, mobile trailer and motor homes against gale-force winds, and more particularly to a cont~inm~nt and protective a~aldl~ls and method for securing such objects to the ground and protecting and co~ inil-g them in gale-force winds.
Back~round of the Invention Objects such as aircraft, small sail and motor boats, vehicles and particularly, trailer and motor homes, due to their light constNction, large surface area and relative low mass, are highly susceptible to damage and destruction from gale-force winds. Notably, gale-force winds have commonly been known to overturn such objects, or worse yet, lift and/or blow them a distance, resultingin severe damage and sometimes complete destruction of the object.
Aircraft are typically anchored to the ground by lines, straps, chains and the like to specific parts associated with the wheels or StNtS of theaircraft.
Objects such as small watercraft, power and sail boats, typically, rest on cradles or blocks formed of wood or steel when stored on land or are 2131qOS
Field of Invention The present invention relates to an appa,dlus and a method for securing objects, particularly, mobile trailer and motor homes against gale-force winds, and more particularly to a cont~inm~nt and protective a~aldl~ls and method for securing such objects to the ground and protecting and co~ inil-g them in gale-force winds.
Back~round of the Invention Objects such as aircraft, small sail and motor boats, vehicles and particularly, trailer and motor homes, due to their light constNction, large surface area and relative low mass, are highly susceptible to damage and destruction from gale-force winds. Notably, gale-force winds have commonly been known to overturn such objects, or worse yet, lift and/or blow them a distance, resultingin severe damage and sometimes complete destruction of the object.
Aircraft are typically anchored to the ground by lines, straps, chains and the like to specific parts associated with the wheels or StNtS of theaircraft.
Objects such as small watercraft, power and sail boats, typically, rest on cradles or blocks formed of wood or steel when stored on land or are 2131qOS
merely restrained by lines secured to and adjacent dockside or buoy when afloat.No other le~ ing means to prevent the boat from being hurled inland in the event of gale-force winds are employed.
Ruil~lings, including residential homes and commercial and retail properties which typically rest on the ground by means of concrete footings and the like are often damaged by gale-force winds. In particular, roofs of buildings may be blown away. Further, the above objects are often damaged by flying debris created by the gale-force winds. Yet further, glasshouses for example, commercial greenhouses, are very susceptible to damage from windborne debris.
Vehicles are also often flung into the air and damaged by such winds.
Although netting has been used to embrace objects such as vehicles and aircraft, particularly as a means of carrying camouflage m~tPri~l, such netting has not been provided over the object as a secure ret~ining means sufficient to with~t~n~ gale-force winds.
Numerous prior art appa,dt~ls exist for securing mobile or trailer homes to the ground in the event of hurricane, flood, or gale-force winds. The majority of these prior art apparatus use a combination or anchor means, elongate strap members and tightening turnbuckles, whereby such strap members are placed over and encircle a mobile home and are affixed to anchor means via turnbuckles to anchor the mobile home to the ground.
U.S. Patents #4,148,162, #4,070,802, #3,051,151, #3,335,531, #3,644,192, #3,747,288, #3,848,367 and #3,937,437 are all examples of such al)pa-~dlus which secure a mobile home to the ground via elongate strap members placed over and encircling the mobile home.
For e~mple, USP #3,054,151 and #4,070,802 each disclose "elongate metallic web-like hold-down straps 12 and 14" (U.S. Patent '802) or hing~ 15H which bridge the roof of the mobile home and are secured at their ends to anchors.
21~105 Indeed, in some states within the United States of America where the incidence of hurricanes is high, such as in the State of Florida, State legicl~tion requires that mobile homes be anchored to the ground in a stipulatedmanner requiring utili7~tion of one of more of the above prior art appaldlus andmethods for securing mobile homes to the ground.
The above prior art a~paldtus, however, are often un~uccessful in preventing damage to mobile homes and small boats due to gale-force winds, since they completely fail to protect these objects from another source of damage, namely, damage due to impact with airborne debris, such as uprooted trees, bricks, flotsam, and the like which may impact the object at high velocity during a hurricane. For example, despite the utili_ation of such prior art a~dldlus, such prior art appald~us ~was unable to prevent the extensive damage and destruction to mobile homes occurred with the State of FloAda due to HurAcane Andrew in August of 1992. DuAng this hurri~n~, trailer homes despite being secured to the ground by pAor art appaldtus suffered mass destruction due to being impacted by airborne projectiles such as trees, bAcks, debAs, the like, which so damaged trailer homes that the elongate strap members were completely ineffective in preventing con~in"~nt of the damaged trailer home. This often and, generally without exception, resulted in the damaged trailer home and its contenls being completely blown away.
Accordingly, pAor art appalalus do nothing to shield a mobile home from bombardment by airborne debAs which frequently impacts a trailer home with such force so as to cause the break-up and disintegldtion of the mobile home. This is extremely undesirable, not only because of the destruction of the subject mobile home, but also because the resl-ltAnt debAs from the destroyed mobile home, including the mobile home's conlellts such as TV's, appliances, andthe like, further add to the airborne debAs circul~ting in a hl-rri.~ne and in turn become airborne and impact and bombard other mobile homes, causing further resultant damage and destruction. Accordingly, the elongate strap members utilized with the appa dlus of the aforementioned patents not only do nothing to ~131~05 ~ 4 ~ SL425 shield a trailer home from airborne bol,lbardlllent, but they further do nothing to contain debris from damaged trailer homes and their conte~ from becoming airborne in a hun~c~n~ and causing further damage and destruction, both to human life and other propelly.
S Use of canvas or nylon tarps or tarpaulins to protect prol~elly from wind and rain is also generally known. However, use of canvas tarps or tarpaulins, for purpose of pr~tecling mobile homes from damage from airborne debris in a hurricane, even if employed in the novel and inventive manner disclosed herein, would highly be un~l-it~hle and indeed unworkable. In particular, to resist large volumes of wind, any canvas or nylon tarpaulins needto be of such thickness that their weight makes them extremely difficult to workwith in placing over a trailer home, not to mention the increased expense in thenumber and size of ground anchor means ne~es~ry to retain the tarpaulin in high winds. In addition, once becoming rain-soaked, tarpaulins tend to sag, thereby trapping water and placing additional weight on the trailer, which if such waterwere allowed to accumulate, may result in structural damage to the trailer home.Accordingly, there exists a real need for a novel a~al~lus and method to shield and anchor plo~lly such as aircraft, boats, buildings and particularly, mobile homes from destruction in gale-force winds. In addition, there exists a further real need to contain res--lt~nt debris from any of such plopelly which may be destroyed due to impact from airborne debris to prevent such debris from itself becoming airborne and causing further destruction.
Summary of the Invention In order to overcome the disadvantages with the prior art, the present invention discloses a means/apparalus for simultaneously shiel~lin~
anchoring, and containing objects such as aircraft, boats, b~ 1ing~, vehicles and trailer homes in the event of gale-force winds.
Advantageously, the appal~lus of the present invention uses wind-permeable pelrol~le sheets means, which in the plerelled embodiment consists of 21~05 flexible webbed netting, which may be placed in a prescribed manner over or around an object which is sought to be protected against impending gale-force winds or a h~irri~ne. The flexible netting extends outwardly and downwardly at an acute angle from an upper part, preferably the top of the object and is affixed S to ground anchors inte~ ed around the periphery of the object, to thereby anchor the net in place.
In such manner, the object is contained within an enclosure, and each of the sides of the object are surrounded by an inclined sloped surface of the net.
Advantageously, by providing an inclined, subst~nti~lly planar, sloped surface around the sides of the object? the object may thereby be pr~ ;led from impact and bombardment by airborne debris during a hurricane, thereby preventing structural damage to the object. The inclined sloped surfaces of the net means allow passage of wind therethrough, but prohibit passage of windborne lS debris such as bricks, stones, such as B3 gravel, trees, flotsam, wood spars and the like, which would otherwise impact and destroy or at least seriously damage,by penetration thereof or otherwise, the object. The ~lrola~e sheet means or netis of s-lfflci~nt strength to resist impact with such projectiles, but further assists in preventing airborne debris from impacting the sides of the object by its sloped configuration, which assists in deflecting such airborne matter over the top of the object and away from the sides.
Accordingly, in its broadest aspect, the a~a.~lus of the present invention comprises the combination of:
(i) an oversize wind-permeable perforate sheet means of a surface area substantially greater than the combined surface area of the top and sides of an object over which it is adapted to be placed, wherein such sheet means is extendable downwardly and oulwa~dly from the top at an acute angle to the sides of the object;
(ii) a plurality of ground anchor means adapted for pl~.e.m~.nt in the ground surrounding said object; and 213~5 (iii) ~tt~ hm~nt means, ~tt~rh~hle to the periphery of the pelrol~le sheet means, to allow the pelrol~te sheet means to be secured to the ground anchor means.
In a further aspect of the present invention, there is ~ie~losed a method of simultaneously shiel~ling, anchoring, and co~ ining an object in the event of gale-force winds. Such method comprises the steps of:
(i) casting an oversize, substantially wind-permeable flexible net means over said object so as to substantially cover the top of the object; and (ii) attaching the wind-permeable net means proximate an outer peripheral edge thereof to ground anchor means, so that the net extends downwardly and outwardly from the top at an acute angle to each of the sides of the object, so as to surround at least a substantial portion of each of the sides with an inclined, wind-permeable surface.
In a p~efelled embodiment, the ap~al~tus of the present invention further comprises the combination of:
(i) an oversize wind-permeable perforate sheet means of a surface area subst~nti~lly greater than the combined surface area of a roof and outer side walls of a trailer home over which it is adapted to be placed, wherein such sheet means is extendable downwardly and oulwal~ly from the roof at an acute angle a to the outer side of the walls of the mobile home;
(ii) a plurality of ground anchor means adapted for placement in the ground surrounding said home; and (iii) att~hmPnt means, ~tt~-h~hle to the periphery of the pelrol~te sheet means, to allow the pelro~dte sheet means to be secured to the ground anchor means.
In a further plefelled embodiment of the present invention, there is disclosed a method of simultaneously shielding, anchoring, and conlahlillg a trailer home or motor home in the event of gale-force winds. Such method comprises the steps of:
(i) casting an oversiæ, subst~nti~lly wind-permeable flexible net means over a mobile home so as to subst~nti~lly cover the roof of the home; and (ii) ~t~ching the wind-permeable net means proximate an outer peripheral edge thereof to ground anchor means, so that the net means extends dowllwa~dly and oulwar~dly from the roof at an acute angle ~ to each of outer side walls of the trailer home, so as to surround at least a substantial portion of each of the outer side walls with an inclined, wind-permeable surface.
Surprisingly, I have found that by providing a net formed of a resili~ntly flexible m~t~ri~l, such as a flexible thermoplastics m~teri~l, sufficiently taut around the object as to give the net one or more flat stationary planes, acutely angled to the object, that windborne debris can be ~ ined and deflected from the object to prevent damage thereto. I have found that when such debris hits the net with app~cciable force, the net is te,l.pol~ily deformed at an area of at least one of these flat, stationary planes under the impact of the flying debris. The resilient net m~teri~l absorbs the energy of impact and surprisingly, this energy is distributed throughout the net ~ nt the impact site and transferred to the restraining anchor means. The extent of this impact energy distribution throughout the net to the anchors allows of the unexpectedly high degree of efficacy of thenet in lc~ ining and deflecting the debris.
Thus, the invention provides a combination and method as hereinabove defined wherein a side or face of the net is so formed as to be deformable from its stationary plane and so biased as to deflect or restrain windborne flying debris by absorbing impact energy by distribution thereof through said m~teri~l.
The net is, thus, so formed and taut as to constitute re~ ontly flexible deflection means to deflect and restrain flying debris.
213~40~i While it is desirable to have the net fully covering the object to be protected, for example, in the case of a building, trailer or mobile home, the roof and sides, the invention is applicable to those situations where only one or more sides need to be protected. One edge of the sheet may be attached to only one side of a structure to protect a window or the like, with the opposite edge being secured to the adjacent ground or surface at a ~ t~nce from the base of the structure. Also within the scope of the present invention are those embc~iment~
wherein the net is spaced away from, but a(ljac~nt an upper part of the object, structure and the like, to be protecled. The net may be directly or indirectly ~upl)o~led on or by a frame so spaced away from the object but to be effective in providing the desired proleclion from windborne debris. Such arrangements in this specification and claims are embraced by the terms "adapted for pl~cem~nt around said object" and "adapted for placement over the roof" and the like.
Thus, the system of the invention in one aspect has the net fully covering the top of the object, for example the roof of a trailer home. This provides a means of ~ inillg and conlaining the home and any contents contained therein should the sides of the home be penetrated to allow air ples~.lr~
build up within the home. In an alternative embo~im~-nt, the home may be contained and restrained by the system notwithstanding the net does not fully cover the top or roof of the home.
The subst~nti~lly wind-permeable, flexible netting extends outwardly and downwardly at an acute angle from an upper part to provide a stationary substantially planar inclined sloped surface around the sides of the object and is of sufficient strength and resilience so as to effect distribution of the energy of impact between windborne debris and the netting throughout the nettingand, optimally, as far as the anchor means. Such efficacious distribution of theimpact energy reduces the likelihood of a breakthrough of the net to allow airborne debris to pass therethrough.
P,cfe"ed flexible m~teri~l~ are resiliently flexible thermoplastics such as the polyolefines, polyesters and polyamides. Preferred polyolefines are 2~3140~
~ 9 ~ SL425 polymers and copolymers of ethylene and propylene with for example other olefines and vinyl acetate. Most prert,led polyethylenes have oriented molecularstructures. A p,efe.led polyamide m~teri~l is Nylon 6,6 copolymer of 1,6-diaminohexene and adipic acid.
I have found that one of the benefits of the pro~;li-~e net system of the invention is a reduction in wind p,~s~.l,e on the windward surface of theobject protected by the net, due to reduced passage of wind through the net.
I have found that when prefe,~d nets of use in the invention were tested to failure by the impact on the net of either a heavy test weight in a drop test or by a projectile fired from an air cannon to effect breakthrough, that the res.llting hole caused by the impact was so localized that the efficacy of the net in continuing to provide a plo~li~e membrane around an object was subst~nti~lly not affected. A protective system capable of such continued efficacy is most valuable. This should be contrasted with systems formed of non-resili-ontly flexible m~teri~ls such as lel-lpel~d and heat strengthened glass, wood, such asplywood, chipboard and the like, aluminum sheeting and steel wire, which are most likely to break, shatter or collapse under co,npandble impact energies.
The mech~nic~l char~cteri~tics of the net of use in the practice of the invention, such as mesh size, fabric denier and fabric and net construction may be readily and suitably determined from the physical characteristics of the flexible material in view of the desired efficacy.
The net of a typical 4m x 4m ~imen~ion, preferably, should be able to withstand an impact energy of at least 400 Joules, more preferably more than 500 Joules and most preferably at least 800 Joules.
The net may optionally be formed, for example, of an extruded, woven or non-woven, knotted, knotless, knitted, crocheted or braided web.
Preferred configurations are those known as a raschel crocheted knit or as a loc1~titch configuration.
2131qO5 A woven i.e. interlocked perpendicular threads configuration is less prer~lled in the practice of the invention. Intersections can easily slip to allow relatively large holes to be formed without actual breakage of any fibres.
In extruded netting, net e4m~nt~ are solid strands of m~t~.ri~l, instead of assemblages of fibres having solid inler~;lions. Extruded netting canbe very cheap, but strength is low due to the lack of the ~lignment of moleculesand stiffnt.ss may be quite high.
Knotted netting is generally formed with pre-assembled cord.
However, small mesh sizes are generally impractical to manufacture, and strengthis lost in the knots. Thus, use of such a configuration requires a heavier net with reduced ability to stop small debris.
Braided netting, where yarns cross each other in a regular pattern, allows for high strength and a high degree of stretch. Intersections can be knotless (e.g. Ultra Cross 0 configuration), giving no reduction in strength.
Intersections allow some limited slip, which may allow failure to a limited degree to propagate from one ~1.omPnt to another.
One edge of net arrangement of use in the invention consists of reinforcement with either 5 cm wide nylon, polyester or polypropylene webbing folded over the edge of the net and stitch~ on, typically with two rows of stitc,hes, to leave a 2.54 cm strip of webbing along the edge. The net may itself be reinforced at the edge by increasing the amount of m~t~.ri~l used in the raschel knit. This is a straightforward procedure with raschel m~.hin~.s, Rings are attached to the edging using 2.54 cm webbing, and straps are used to attach these rings to a peripheral cable, which is in turn ?~tt~h~cl to ground anchors.
The size of the mesh of the net not only influences the range of projectile sizes which the net will stop, but also is a factor in the capability to absorb the energy of an impact. Smaller mesh sizes allow objects to strike more net elements, which better dissipates the impact energy. In order to withstand agiven impact, a net with larger mesh size has to weigh more than a net with smaller mesh size.
213~405 Further objects and advantages of this invention will appear from the following detailed description of the invention.
Brief Descliption of the DrawinPs 5In order that the invention may be better understood, plef~lled emb~liments will now be described by way of example only with reference to the acco.npanying drawings, wherein:
Fig. 1 is a perspective view of the a~)paratus of the present invention, in its intended-use position to shield, anchor, and contain a trailer home 10in gale-force winds;
Fig. 2 is a plan view of the appal~lus of the present invention, in the direction of arrow "A" in Fig. l;
Fig. 3 is a section view of the appa-~tus of the present invention, taken along plane B-B of Fig. 2;
15Fig. 4 is an enlarged cross-sectional view of the attachment means and anchor means of the present invention shown in Fig. 3;
Fig. 5 is a view of an arrow 'c' of Fig. 4;
Fig. 6 is a pel~ re view of another embodiment of the appa,~lus of the present invention, in its intended-use position to shield, anchor, 20and contain a trailer home in gale-force winds; and Fig. 7 is an enlarged view on the area de~ign~ted as 'F' in Figs.
1 and 6 showing coupling means for joining sections of pelro~te sheet together.
Detailed Descli~ion of the Invention 25Figs. 1 and 6 show a perspective view of two different embo~im~nt~ of the ap~a~atus 10 and method of the present invention for securin~trailer homes and motor homes 12 (hereinafter mobile homes) against gale-force winds.
An oversized, substantially wind-permeable pelrolale sheet means 3014, capable of being cast or placed over the roof 16 of a mobile home 12, -is - 213;~05 conleml)lated as an essen~i~l component of the app~dlus 10 of the present invention. In the prert;ll~d embodiment, the pelroldle sheet means 14 is a flexible woven net, preferable formed of a water-resistant braided polyethylene.The surface area of the sheet means or net 14 of the present invention is greater than the combined surface area of the roof 16 and side walls 18 of the trailer home 12. This excess size is ill~ t, since a n~es~ry requirement of the invention is that net 14 when placed over the roof 16 of the mobile home be adapted to extend downw~rdly and also oulw~dly from the roof 16 at an acute angle a to the outer side walls 18 of the mobile home so as to create a protective inclined sloped surface 25 around each outer wall 18, as shown in Fig. 1, 2 and particularly Fig. 3.
In a plefe~led emboliment net 14 extends downwardly and outwardly so that the outer pe~ipht;l~l edge 20 thereof extends to at least the level of the lowermost portion 22 (floor) of the mobile home 12, so as to provide a protective inclined surface 25 proximate the entire surface of each outer wall 18 of the mobile home, as shown in Fig. 3.
Attachment means 24 are further provided, as shown in Fig. 1 and in greater detail in Figs. 4 and 5, ~tt~t~h~hle to the pelroldte sheet means 14 proximate the outer peripheral edge 20 thereof. Such attachment means 24 allow net 14 to be ~tt~hPd to ground anchor members 30 located in the earth surrounding the mobile home 12 (see Figs. 4 and 5), to thereby m~int~in net 14 in the angular outwardly extending position as shown in Fig. 3 around all outer sides 18 of mobile home 12. More particularly, it is desirous that the anchor means 30 be int~ cd about the periphery of mobile home 12, as shown in Figs. 1 and 2, and the ~im~nsinns of net 14 be such that net 14 is m~inhined at an outwardly extending angle c~ from the outer walls 18, as shown in Fig. 3. In a p~relled embodiment angle a so formed between the net and the outer side walls is between 15-60 and preferably between 20-35. Angle ~ should be a coll,promise between as high a value as possible to thereby afford as a "shock-absorbing" distance between net 14 and outer walls 18 to allow net 14 to protect walls 18 from airborne debris, while at the same time being as low a value as possible to thereby minimi7P. the size of the net means 14 required.
Since mobile homes are generally of sizes ranging from 30 ft. - 45 ft. in length (floor to roof), by 10 ft. in width, net 14 needs to be of a general rectangular shape of at least 30' x 50' (1,500 sq. ft.) for the .sm~llest trailer home size of 30' x 8' x 10', in order to have a protective in~`lin~ sloped surface 25extending outwardly and angularly downw~dly to protect subst~nti~lly all of the outer side walls 18 of mobile home 12 to the level of the floor 22 of the trailer home. Dimensions of this si7e will permit an angular slope o~ of net 14 of up toapproximately 30. Angle ~Y should be the greate~t value possible at which net 14 will extend with its peripheral edge 20 to a position level with the floor surface 22 of the mobile home, to thereby ensure walls 18 are entirely pro~led from horizontally-moving airborne debris.
Mobile home sizes greater than 30' x 8' x 10' require nets 14 of dimPn~ions larger than 1,500 sq.ft. if an angle ~ is to be m~int~ined and if peripheral edge 20 of net 14 is to extend to a level of floor 22 to thereby protect - all of the surface area of the outer walls 18 from impact damage due to airborne debris.
Notable, in order that net 14 when placed over the mobile home be adapted to extend evenly and uniformly downwardly and outwardly with a minimum of bunching and folding in a plerelled embodiment the pelroldte sheet means is comprised of two or more irregular shaped ~lr~ldte sheets or nets 14' joinable along various seems 40, as shown for example in Figs. 1, 2 and 7.
Accordingly, when a pelrolate sheet means 14 assembled in the prece~lin~ manner is placed over mobile home 12 and attached to the anchor means 30, a wrinkle and bunch-free sloped surface 25 is thereby formed proximate each of outer walls18 of mobile home 12, as shown in Figs. 1, 2 and 6.
To accomplish the joining of each of the various perforate sheets 14' which comprise entire net 14 releasable coupling means 42 may be utilized to join the pe,roldle sheets along a seam 40 thereof, as shown in Fig. 7. These - 213:~405 coupling means 42 may be of any type commonly known in the art, but in a pl~relred embodiment are a steel 'D'-shaped snap-ring.
Advantageously, releasable coupling means 42 along one or more seams 40 allows entry by a person in and out of the mobile home 12 when the appal~lus 10 of the present invention is assembled about the mobile home.
Notable, the force exerted by gale-force winds of up to 150-160 miles per hour, as was recently experienced in H--rrir~ne Andrew which struck the eastern seaboard of the State of Florida and some of the other states surrounding the Gulf of Mexico, including Louici~n~ in August 1992, can be quite ~ignific~nt.
Utilizing the formulas:
P = C x v2 and F = PxA
where: P is p~s~ul~ in lbs. force exerted on an area, C is a constant of 0.0027 x lb hr2 ft2mi2 (~sllming air at a specified density at standard te.l-pel~lure and pressure) V is velocity in miles per hour, and A is the surface area, the maximum force exerted by a wind of a given velocity against a perpendicularly-disposed outer wall 18 of a trailer home of a given area A can easily be calculated.
From Table 1, it can be seen that the force exerted by a gale-force wind of 160 miles per hour on a mobile home size of 45' x 8' (xlO') can exceed 24,000 pounds.
~131~U~
Table 1 Wind Speed (mph) Wall Size S P r e s s u r e of Mobile Force (lbs (lb/ft2) Home (ft2) 6.75 280 (35' x 8') 2430 6.75 360 (45' x 8') 9.72 280 (35' x 8') 3499 9.72 360(45' x 8') 13.23 280 (35' x 8') 4763 13.23 360 (45' x 8') 17.28 280(35' x 8') 6221 17.28 360 (45' x 8') 21.87 280 (35' x 8') 7873 100 21.87 360 (45' x 8') 27 280 (35' x 8') 9720 110 27 360 (45' x 8') 32.67 280 (35' x 8') 11761 120 32.67 360 (45' x 8') 38.88 280 (35' x 8') 13997 130 38.88 360 (35' x 8') 45.63 280 (35' x 8') 16427 140 45.63 360 (45' x 8') 52.92 280 (35' x 8') 19051 150 52.92 360 (45' x 8') 60.75 280 (35' x 8') 21870 160 60.75 360 (45' x 8') 69.12 280 (35' x 8') 24883 69.12 360 (45' x 8') 2~3~sos To resist a force of such m~nihlde applied by a 160 mile per hour wind perpendicularly cont~cting a wall of a mobile home, the net means 14 is affixed to suitable anchoAng means 30. It is cont~lnplated that anchor means 30 of the present invention be comprised of elong~t~, multi-helix screwable anchors30, which may be m~h~ni-~lly screwed into the ground (see Fig. 3).
A number of such anchor members 30 are commercially available.
One such product is multi=helix anchor manufactured by Dixie Electrical manuf~t~lring Company of Birmingh~m, ~l~h~m~, under Cat. No. D-284 for a tandem 8" helix anchor. According to information supplied by said co~llpany, such anchor ~lepen(ling on soil type and length of anchor, when inserted into the soil can resist a load of between 10,000 to 30,000 lbs. Using such information, knowing of the approp,iate soil conditions, the n~s~ry approximate spacing of such anchor means 30 around the periphery of a mobile home can be delell--ined to secure net 14 about a mobile home 12.
To avoid anchor means 30 protruding upwardly and creating a safety hazard, it is conle...plated in a p~re"~ embodiment that anchor means 30 be recessed below the surface of the earth, as shown in Fig. 3, 4 and 5. To f~r,ilit~t~. this, a r~ss~d well 70 may be further provided to su"ound anchor means 30, within which a cylindrical hollow canister 50 may be placed level withthe surface of the ground, as shown in Figs 3, 4 and 5. When anchor means 30 and appal~tus 10 of the present invention is not in use, a cylindrical cover plate (not shown) may be placed over the cylindrical canister 50, to thereby conceal and hide anchor means 30 from view.
Commercially available cylindrical canister devices 50 and cover plates suitable for such purposes are presently commercially available. For example, Brooks Products Inc., Polyplastic Division, of Cucamonga, California provides a "60 series Valve Box" which is ideally suited to this pu,~ose.
The ~tt~l~hment means 24 of the present invention may simply comprise a releasable attachment mçch~ni~m, such as a snap-ring, for releasably ~tt~rhing the net 14 at any point proximate the peripheral edge thereof directly to 213~40~
anchor means 30, as shown in Fig. 6. In a pferel~d emb~liment, however, it is conte,l-plated that the ~tt~hm~nt means 24 further comprise means for tight~n~l~ly securing flexible net 14 to anchor members 30.
Accordingly, it is further contelllplated that ~tt~hm~nt means 24 comprise a pair of releasably securable hooks 60, 62, one of which may be secured to anchor 30 and the other to net 14 as shown in Figs. 4 and 5. Rollablewebbing connects the two hooks 60, 62, and crankable tip=htenin~ means 70 is further provided to rollably wind the webbing 72 onto a spool 74, thereby bringing hooks 60, 62 together to thereby tighten net 14 to anchor 30, as shown in Figs. 4 and 5. An example of such a commercially available ti~htening means ideally suited to this purposes is model FE 400 (P/N802) Ratchet Strap, sold by Kenedyne Corporation of North Branch, New Jersey, having a breaking strength of 11,000 lbs., with a 2" cranking handle, and hooks 60, 62 interposed at each end.
An extremely lightweight and water resistant high-strength fibre particulary suited for net means 14 of the present invention is a braided line netting comprised of a polyethylene homopolymer having a high modulus of elasticity and a molecular weight of over 500,000. An example of such a commercially available fibre is SPECTRA~' manufactured by Allied Fibers, a division of Allied Signal Inc. of Petersburg, Virginia. In ~4 " single braid format, such fiber has a break strength of approximately 48,000 lbs., and a weight of approximately 22 lbs. per 100 ft. of rope.
EXAMPLES
1. Raschel Nylon Tension Tests In order to accurately model the impact of a projectile on the netting, data regardillg the stiffness and strength of the netting was obtained.
Trade Mark of Allied Signal Inc. for polyethylene twine and rope.
- 2~3~ 5 Simple static tension tests were pelrolllled, with load and strain data recorded at several points for each sample.
Sample Pr~)al~lion Specimens of nylon fibres were cut from a large section of netting.
A single strand (o.25 cm) of the netting was followed through a series of intersections. To avoid adverse effects on the test strand, intersection strandswere cut roughly five diameters away from the intersection. All cuts were made with a soldering iron to elimin~te unravelling. Typical sample lengths were 1.2 m.
To f~ilit~te gripping of the spe~im~n, and to ensure that failure occurred in the test section of the sample, the ends of each sample were threaded through the hollow core of a short length of 0.5 cm braided nylon rope. A clamp on the end of the rope nearest the test section, along with a knot a short distance away, elimin~ted the possibility of slippage of the specimen through the rope.
Experimental Procedure The test apparatus used was a Tinius-Olsen tension/colllpression test rig. Samples (inside the rope) were wound around a 4 cm dia. steel pipe) to avoid stress concentrations and tied off to a post. Elastic strands were ~tt~rlled to each sample at the end of the test section as references for strain measurements.
Typical crosshead separation rate was 20 mm/min. Deflections were manually measured at specific loads (e.g. every 4 Kg).
Maximum load ~uppolled by each sample was also recorded.
Results A typical plot of load vs. deflection is shown in Table 2.
- 2~31~
Table 2 Load (N) Strain (no. units) O O
49 0.09 0.15 140 0.20 175 0.24 225 0.27 260 0.28 310 0.30 355 0.32 400 0.33 2. Dropped Projectile Impact Tests Large samples of netting were tested for impact absorption capability through drop tests. The sample to be tested was securely fastened to a rigid frame, and a projective of measured weight and dim~nsions was dropped onto the specimPn from a range of measured heights.
Apparatus The netting used was 210/20 twine, (Hafner Fabrics, Toronto, Ontario Canada), 1.27 cm of stretched mesh 100% Nylon 6,6 (Du Pont) raschel - knit configuration. The raschel knit is a knotless configuration, with strands and intersections 'crocheted' together. The design~tion 210/20 indicates that 20 ends of 210 denier fibre form the yarn. The res--lting twine was roughly 1 mm in ~ m~ter. The mesh had a breaking strength of 25 kgs. and the mesh squares were roughly 6 mm wide.
Breaking strength is an indication of the net's capabilities.
Breaking strength is measured by pulling apart one square of the fini~hed product, so the element strength is half the breaking strength. Denier is a measure of a fibre's weight. One denier is equivalent to the weight in grams of a 9000 m length of the fibre. Thus, a 9000 m length of 210 denier fibre would weigh 210 grams. Stretched mesh size indicates the ~ t~nce between inte~ ions, along two sides of a square. Thus 1.27 cm stretched mesh colr~sponds to roughly 0.635 cm squares.
21~05 The raschel knit construction technique consists of es~P-nti~lly crocheting the yarns (three yarns together at a time) and forming loops in the net elPmPnt~. Intel~clions between elemPnt~ of the net are accomplished without knots; the crochet process continues through the int~,r~;lion, with one yarn being exchanged between the int~,~cling ele~ment.~. A main advantage of the raschel knit is its ability to stretch to a large degree: as much as 50% strain-to-failure for an element.
Another advantage of raschel is that, if one elPment of the net is damaged, there is no ten-lPncy for adjacent inlersections, or adj~cent el~Pm~-nts~ to unravel. This avoids single-point failures.
A third advantage is that intersections cannot slip signific~ntly, due to the exchange of yarns. Thus an opening can not be stretched wider by wind or impacts.
One more advantage is that no ~ignifit~nt strength is lost in inte~s~;~ions. Knotted netting configurations lose ~ignific~nt p~lroll-lance due to the stress concentrations of the knots.
A system for edge ~ttaçhmPnt was installed on each sample of netting to be tested. Earlier versions of this consisted of a rope or cable strung through the outside squares of the netting, the latter version consisted of a length of 5 cm webbing sewn onto the edge of the netting, with D-rings ~tt~t~he~ to this webbing using small 2.54 cm pieces of webbing A rigid frame, roughly 4 m square, was constructed from 10 cm angle iron to support the test samples. 2.5 cm eye bolts were attached to the inside corners and at the centres of each side of the frame. A 0.6 cm cable was strung through the eye bolts and tight~PnP-d with a turnbuckle. The netting was attached to this cable by stringing a rope between the edge attachment system and the cable every foot or so along the perimeter of the sample.
The degree to which the test specimen was stretched into place depended on the type of edge ~tt~chmPnt - the webbing allowed for very little 2~31405 stretch, whereas the rope strung through the edge allowed for ample pre-stressing (approximately 13.7%).
The projectile used was a still cylinder roughly 9 cm di~mPt~r, roughly 20 cm long, and 11.7 Kgs weight. As the projectile had fairly sharp S edges, tape was placed around the bottom edge to avoid cuffing the test specimen.
A ring was ~tt~ ed to the tope of the weight to support it from the crane.
Experimental Procedure The hook of a crane was placed above the centre of the net. A
rope was strung through the hook and ~tt~hed to the projectile. A tape measure attached to the hook was used to measure the height of the projective above the net. The projectile was dlopped from increasing heights until the net failed. A
video camera recorded all tests, and was used to measure displ~Rm~nt of the net,as indicated by a scale on the far side of the frame.
Results lS The maximum height from which a projectile could be dropped without d~m~ging the net ranged from 9.3 m (for the pre-stretched sample) to I0.21 m (for the unstretched sample), which col~s~nds to an impact energy of 1100 to 1200 Joules. The maximum displ~rem~-nt of the pre-stretched sample was approximately 1.0 m whereas the maximum displacement of the unstretched sample was approximately 1.3 m. The holes left by imp~t~ from a greater height were typically 20 cm in ~i~me~er. The force of impact was s~-fficient to do .~ignifi(~nt damage to the corner eyebolts. After the series of roughly lS tests, the eyes had been forced open, leaving gaps as large as 2 cm.
The nets were tested to failure. After the first intentional failure of the netting, several subsequent drop tests were pelroll"ed on the netting.
Results from these tests and direct observations in~ t~ that damage to the net was limited to the imm~i~te vicinity of the actual hole; outside a small lS cm distance away from the hole, the net ~l~o~l"ed as well as it had before being damaged.
3. Air Cannon Tests 21~1405 Impact tests were pe,rol-l-ed using a standardised air-propelled wood projectile at American Test Laboratory in Pompano Beach, Florida, U.S.A., to simulate hurri~ne force winds-windborne debris.
Apparatus Similar netting - Nylon 6,6 raschel knit, was used for this test as in the previous drop-tests. The edge attachment system used was a 5 cm webbing sewn around the edge of the samples, with D-rings att~hed with 2.54 cm webbing, spaced roughly 30 cm apart.
A bolted wooden frame of approximately 4 m square was used as part of the le~ ing means. 1.3 cm eye bolts were mounted through the wood at each corner of the frame and in the centres of the sides. 0.6 cm cable was strung through the eye bolts and tightened with a turnbuckle. Rope was used to attach the D-rings to the cable. Tension in the netting was low.
The cannon used to propel the projectile consisted of an air col--pressor, an air reservoir with a pressure gauge, a 10 cm air line, a manually activated bulle~lly valve, and a 10 cm PVC tube as a barrel of the cannon.
The end of the cannon was approximately 7.5 m from the flat, vertical stationaryplane of net.
The projectile was a 4 Kg, 5 cm x 10 cm x 2.4 m Southern Pine member having its front end slightly rounded. A 10 cm ~ m~ter disc was attached to the back end to provide a p~ess..le seal for the barrel of the air cannon.
Procedure Four tests were pe,rol-lled at increasing speeds: 65, 80, 90, and 100 feet per second (fps). Speed had been previously calibrated to reservoir pres~.lre at ples~u~s up to 80 fps, and an extrapolation was made from this datato calculate the pres~u~ required to provide the higher speeds. The tests were recorded on videotape and also provided the displacement of the netting during impact.
2131~0~-Results The net withstood the impact of the 5cm x 10 cm x 2.4 m rectangular wood projective at the aforesaid ~4cted three speeds of up to 90 fps, with net defo~ a~ion from its flat stationary plane of up to 1.1 m. At 100 fps, the net failed, leaving a 33 cm x 30 cm rectangular hole. Surprisingly, the eyebolts in each of the corners of the frame showed $ignifi~nt alteration in that their eyes had been prised opened and the bolt shanks bent by as much as 15 degrees. This in~ ~ted that the cumulative force of impacts of the four speeds had been si~nific~ntly large and had been transferred through the net material to each of the bolts. It should also be noted that the 90 fps test success indicates that the net is capable of with~t~n~ling more than three times the energy of thestandard impact test of 50 fps.
Similar air cannon impact tests with the 5 cm x 10 cm x 2.4m wood member conducted on 1.5 cm thick plywood and on 6 mm thick l~l-lpe ed and heat strengthened glass produced penetration of the plywood and breakage of the glass at 50 fps.
The degree of resiliency of the material e1enl~nt of the net was measured for two netting configurations: 210/20 nylon, and 18/80 polypropylene raschel. Maximum elongation for the nylon was roughly 34%, whereas the poly~r~ylene stretched as much as 50%. Tests showed that in one test an impact energy of approximately 800 joules on the above nylon 210/20 netting was readilyabsorbed by the net system while providing a displacement of approximately 0.7m. A 18/18 polypropylene net of 65% of the areal weight of nylon 210/20 also withstood the same impact of the wooden member at 20 m/s and provided a deformation of approximately 1 m.
Although the disclosure describes and illustrates plere.led embo limPnts of the invention, it is to be understood that the invention is not limited to these particular embo~im~nt~. Many variations and modifications will now occur to those skilled in the art.
Ruil~lings, including residential homes and commercial and retail properties which typically rest on the ground by means of concrete footings and the like are often damaged by gale-force winds. In particular, roofs of buildings may be blown away. Further, the above objects are often damaged by flying debris created by the gale-force winds. Yet further, glasshouses for example, commercial greenhouses, are very susceptible to damage from windborne debris.
Vehicles are also often flung into the air and damaged by such winds.
Although netting has been used to embrace objects such as vehicles and aircraft, particularly as a means of carrying camouflage m~tPri~l, such netting has not been provided over the object as a secure ret~ining means sufficient to with~t~n~ gale-force winds.
Numerous prior art appa,dt~ls exist for securing mobile or trailer homes to the ground in the event of hurricane, flood, or gale-force winds. The majority of these prior art apparatus use a combination or anchor means, elongate strap members and tightening turnbuckles, whereby such strap members are placed over and encircle a mobile home and are affixed to anchor means via turnbuckles to anchor the mobile home to the ground.
U.S. Patents #4,148,162, #4,070,802, #3,051,151, #3,335,531, #3,644,192, #3,747,288, #3,848,367 and #3,937,437 are all examples of such al)pa-~dlus which secure a mobile home to the ground via elongate strap members placed over and encircling the mobile home.
For e~mple, USP #3,054,151 and #4,070,802 each disclose "elongate metallic web-like hold-down straps 12 and 14" (U.S. Patent '802) or hing~ 15H which bridge the roof of the mobile home and are secured at their ends to anchors.
21~105 Indeed, in some states within the United States of America where the incidence of hurricanes is high, such as in the State of Florida, State legicl~tion requires that mobile homes be anchored to the ground in a stipulatedmanner requiring utili7~tion of one of more of the above prior art appaldlus andmethods for securing mobile homes to the ground.
The above prior art a~paldtus, however, are often un~uccessful in preventing damage to mobile homes and small boats due to gale-force winds, since they completely fail to protect these objects from another source of damage, namely, damage due to impact with airborne debris, such as uprooted trees, bricks, flotsam, and the like which may impact the object at high velocity during a hurricane. For example, despite the utili_ation of such prior art a~dldlus, such prior art appald~us ~was unable to prevent the extensive damage and destruction to mobile homes occurred with the State of FloAda due to HurAcane Andrew in August of 1992. DuAng this hurri~n~, trailer homes despite being secured to the ground by pAor art appaldtus suffered mass destruction due to being impacted by airborne projectiles such as trees, bAcks, debAs, the like, which so damaged trailer homes that the elongate strap members were completely ineffective in preventing con~in"~nt of the damaged trailer home. This often and, generally without exception, resulted in the damaged trailer home and its contenls being completely blown away.
Accordingly, pAor art appalalus do nothing to shield a mobile home from bombardment by airborne debAs which frequently impacts a trailer home with such force so as to cause the break-up and disintegldtion of the mobile home. This is extremely undesirable, not only because of the destruction of the subject mobile home, but also because the resl-ltAnt debAs from the destroyed mobile home, including the mobile home's conlellts such as TV's, appliances, andthe like, further add to the airborne debAs circul~ting in a hl-rri.~ne and in turn become airborne and impact and bombard other mobile homes, causing further resultant damage and destruction. Accordingly, the elongate strap members utilized with the appa dlus of the aforementioned patents not only do nothing to ~131~05 ~ 4 ~ SL425 shield a trailer home from airborne bol,lbardlllent, but they further do nothing to contain debris from damaged trailer homes and their conte~ from becoming airborne in a hun~c~n~ and causing further damage and destruction, both to human life and other propelly.
S Use of canvas or nylon tarps or tarpaulins to protect prol~elly from wind and rain is also generally known. However, use of canvas tarps or tarpaulins, for purpose of pr~tecling mobile homes from damage from airborne debris in a hurricane, even if employed in the novel and inventive manner disclosed herein, would highly be un~l-it~hle and indeed unworkable. In particular, to resist large volumes of wind, any canvas or nylon tarpaulins needto be of such thickness that their weight makes them extremely difficult to workwith in placing over a trailer home, not to mention the increased expense in thenumber and size of ground anchor means ne~es~ry to retain the tarpaulin in high winds. In addition, once becoming rain-soaked, tarpaulins tend to sag, thereby trapping water and placing additional weight on the trailer, which if such waterwere allowed to accumulate, may result in structural damage to the trailer home.Accordingly, there exists a real need for a novel a~al~lus and method to shield and anchor plo~lly such as aircraft, boats, buildings and particularly, mobile homes from destruction in gale-force winds. In addition, there exists a further real need to contain res--lt~nt debris from any of such plopelly which may be destroyed due to impact from airborne debris to prevent such debris from itself becoming airborne and causing further destruction.
Summary of the Invention In order to overcome the disadvantages with the prior art, the present invention discloses a means/apparalus for simultaneously shiel~lin~
anchoring, and containing objects such as aircraft, boats, b~ 1ing~, vehicles and trailer homes in the event of gale-force winds.
Advantageously, the appal~lus of the present invention uses wind-permeable pelrol~le sheets means, which in the plerelled embodiment consists of 21~05 flexible webbed netting, which may be placed in a prescribed manner over or around an object which is sought to be protected against impending gale-force winds or a h~irri~ne. The flexible netting extends outwardly and downwardly at an acute angle from an upper part, preferably the top of the object and is affixed S to ground anchors inte~ ed around the periphery of the object, to thereby anchor the net in place.
In such manner, the object is contained within an enclosure, and each of the sides of the object are surrounded by an inclined sloped surface of the net.
Advantageously, by providing an inclined, subst~nti~lly planar, sloped surface around the sides of the object? the object may thereby be pr~ ;led from impact and bombardment by airborne debris during a hurricane, thereby preventing structural damage to the object. The inclined sloped surfaces of the net means allow passage of wind therethrough, but prohibit passage of windborne lS debris such as bricks, stones, such as B3 gravel, trees, flotsam, wood spars and the like, which would otherwise impact and destroy or at least seriously damage,by penetration thereof or otherwise, the object. The ~lrola~e sheet means or netis of s-lfflci~nt strength to resist impact with such projectiles, but further assists in preventing airborne debris from impacting the sides of the object by its sloped configuration, which assists in deflecting such airborne matter over the top of the object and away from the sides.
Accordingly, in its broadest aspect, the a~a.~lus of the present invention comprises the combination of:
(i) an oversize wind-permeable perforate sheet means of a surface area substantially greater than the combined surface area of the top and sides of an object over which it is adapted to be placed, wherein such sheet means is extendable downwardly and oulwa~dly from the top at an acute angle to the sides of the object;
(ii) a plurality of ground anchor means adapted for pl~.e.m~.nt in the ground surrounding said object; and 213~5 (iii) ~tt~ hm~nt means, ~tt~rh~hle to the periphery of the pelrol~le sheet means, to allow the pelrol~te sheet means to be secured to the ground anchor means.
In a further aspect of the present invention, there is ~ie~losed a method of simultaneously shiel~ling, anchoring, and co~ ining an object in the event of gale-force winds. Such method comprises the steps of:
(i) casting an oversize, substantially wind-permeable flexible net means over said object so as to substantially cover the top of the object; and (ii) attaching the wind-permeable net means proximate an outer peripheral edge thereof to ground anchor means, so that the net extends downwardly and outwardly from the top at an acute angle to each of the sides of the object, so as to surround at least a substantial portion of each of the sides with an inclined, wind-permeable surface.
In a p~efelled embodiment, the ap~al~tus of the present invention further comprises the combination of:
(i) an oversize wind-permeable perforate sheet means of a surface area subst~nti~lly greater than the combined surface area of a roof and outer side walls of a trailer home over which it is adapted to be placed, wherein such sheet means is extendable downwardly and oulwal~ly from the roof at an acute angle a to the outer side of the walls of the mobile home;
(ii) a plurality of ground anchor means adapted for placement in the ground surrounding said home; and (iii) att~hmPnt means, ~tt~-h~hle to the periphery of the pelrol~te sheet means, to allow the pelro~dte sheet means to be secured to the ground anchor means.
In a further plefelled embodiment of the present invention, there is disclosed a method of simultaneously shielding, anchoring, and conlahlillg a trailer home or motor home in the event of gale-force winds. Such method comprises the steps of:
(i) casting an oversiæ, subst~nti~lly wind-permeable flexible net means over a mobile home so as to subst~nti~lly cover the roof of the home; and (ii) ~t~ching the wind-permeable net means proximate an outer peripheral edge thereof to ground anchor means, so that the net means extends dowllwa~dly and oulwar~dly from the roof at an acute angle ~ to each of outer side walls of the trailer home, so as to surround at least a substantial portion of each of the outer side walls with an inclined, wind-permeable surface.
Surprisingly, I have found that by providing a net formed of a resili~ntly flexible m~t~ri~l, such as a flexible thermoplastics m~teri~l, sufficiently taut around the object as to give the net one or more flat stationary planes, acutely angled to the object, that windborne debris can be ~ ined and deflected from the object to prevent damage thereto. I have found that when such debris hits the net with app~cciable force, the net is te,l.pol~ily deformed at an area of at least one of these flat, stationary planes under the impact of the flying debris. The resilient net m~teri~l absorbs the energy of impact and surprisingly, this energy is distributed throughout the net ~ nt the impact site and transferred to the restraining anchor means. The extent of this impact energy distribution throughout the net to the anchors allows of the unexpectedly high degree of efficacy of thenet in lc~ ining and deflecting the debris.
Thus, the invention provides a combination and method as hereinabove defined wherein a side or face of the net is so formed as to be deformable from its stationary plane and so biased as to deflect or restrain windborne flying debris by absorbing impact energy by distribution thereof through said m~teri~l.
The net is, thus, so formed and taut as to constitute re~ ontly flexible deflection means to deflect and restrain flying debris.
213~40~i While it is desirable to have the net fully covering the object to be protected, for example, in the case of a building, trailer or mobile home, the roof and sides, the invention is applicable to those situations where only one or more sides need to be protected. One edge of the sheet may be attached to only one side of a structure to protect a window or the like, with the opposite edge being secured to the adjacent ground or surface at a ~ t~nce from the base of the structure. Also within the scope of the present invention are those embc~iment~
wherein the net is spaced away from, but a(ljac~nt an upper part of the object, structure and the like, to be protecled. The net may be directly or indirectly ~upl)o~led on or by a frame so spaced away from the object but to be effective in providing the desired proleclion from windborne debris. Such arrangements in this specification and claims are embraced by the terms "adapted for pl~cem~nt around said object" and "adapted for placement over the roof" and the like.
Thus, the system of the invention in one aspect has the net fully covering the top of the object, for example the roof of a trailer home. This provides a means of ~ inillg and conlaining the home and any contents contained therein should the sides of the home be penetrated to allow air ples~.lr~
build up within the home. In an alternative embo~im~-nt, the home may be contained and restrained by the system notwithstanding the net does not fully cover the top or roof of the home.
The subst~nti~lly wind-permeable, flexible netting extends outwardly and downwardly at an acute angle from an upper part to provide a stationary substantially planar inclined sloped surface around the sides of the object and is of sufficient strength and resilience so as to effect distribution of the energy of impact between windborne debris and the netting throughout the nettingand, optimally, as far as the anchor means. Such efficacious distribution of theimpact energy reduces the likelihood of a breakthrough of the net to allow airborne debris to pass therethrough.
P,cfe"ed flexible m~teri~l~ are resiliently flexible thermoplastics such as the polyolefines, polyesters and polyamides. Preferred polyolefines are 2~3140~
~ 9 ~ SL425 polymers and copolymers of ethylene and propylene with for example other olefines and vinyl acetate. Most prert,led polyethylenes have oriented molecularstructures. A p,efe.led polyamide m~teri~l is Nylon 6,6 copolymer of 1,6-diaminohexene and adipic acid.
I have found that one of the benefits of the pro~;li-~e net system of the invention is a reduction in wind p,~s~.l,e on the windward surface of theobject protected by the net, due to reduced passage of wind through the net.
I have found that when prefe,~d nets of use in the invention were tested to failure by the impact on the net of either a heavy test weight in a drop test or by a projectile fired from an air cannon to effect breakthrough, that the res.llting hole caused by the impact was so localized that the efficacy of the net in continuing to provide a plo~li~e membrane around an object was subst~nti~lly not affected. A protective system capable of such continued efficacy is most valuable. This should be contrasted with systems formed of non-resili-ontly flexible m~teri~ls such as lel-lpel~d and heat strengthened glass, wood, such asplywood, chipboard and the like, aluminum sheeting and steel wire, which are most likely to break, shatter or collapse under co,npandble impact energies.
The mech~nic~l char~cteri~tics of the net of use in the practice of the invention, such as mesh size, fabric denier and fabric and net construction may be readily and suitably determined from the physical characteristics of the flexible material in view of the desired efficacy.
The net of a typical 4m x 4m ~imen~ion, preferably, should be able to withstand an impact energy of at least 400 Joules, more preferably more than 500 Joules and most preferably at least 800 Joules.
The net may optionally be formed, for example, of an extruded, woven or non-woven, knotted, knotless, knitted, crocheted or braided web.
Preferred configurations are those known as a raschel crocheted knit or as a loc1~titch configuration.
2131qO5 A woven i.e. interlocked perpendicular threads configuration is less prer~lled in the practice of the invention. Intersections can easily slip to allow relatively large holes to be formed without actual breakage of any fibres.
In extruded netting, net e4m~nt~ are solid strands of m~t~.ri~l, instead of assemblages of fibres having solid inler~;lions. Extruded netting canbe very cheap, but strength is low due to the lack of the ~lignment of moleculesand stiffnt.ss may be quite high.
Knotted netting is generally formed with pre-assembled cord.
However, small mesh sizes are generally impractical to manufacture, and strengthis lost in the knots. Thus, use of such a configuration requires a heavier net with reduced ability to stop small debris.
Braided netting, where yarns cross each other in a regular pattern, allows for high strength and a high degree of stretch. Intersections can be knotless (e.g. Ultra Cross 0 configuration), giving no reduction in strength.
Intersections allow some limited slip, which may allow failure to a limited degree to propagate from one ~1.omPnt to another.
One edge of net arrangement of use in the invention consists of reinforcement with either 5 cm wide nylon, polyester or polypropylene webbing folded over the edge of the net and stitch~ on, typically with two rows of stitc,hes, to leave a 2.54 cm strip of webbing along the edge. The net may itself be reinforced at the edge by increasing the amount of m~t~.ri~l used in the raschel knit. This is a straightforward procedure with raschel m~.hin~.s, Rings are attached to the edging using 2.54 cm webbing, and straps are used to attach these rings to a peripheral cable, which is in turn ?~tt~h~cl to ground anchors.
The size of the mesh of the net not only influences the range of projectile sizes which the net will stop, but also is a factor in the capability to absorb the energy of an impact. Smaller mesh sizes allow objects to strike more net elements, which better dissipates the impact energy. In order to withstand agiven impact, a net with larger mesh size has to weigh more than a net with smaller mesh size.
213~405 Further objects and advantages of this invention will appear from the following detailed description of the invention.
Brief Descliption of the DrawinPs 5In order that the invention may be better understood, plef~lled emb~liments will now be described by way of example only with reference to the acco.npanying drawings, wherein:
Fig. 1 is a perspective view of the a~)paratus of the present invention, in its intended-use position to shield, anchor, and contain a trailer home 10in gale-force winds;
Fig. 2 is a plan view of the appal~lus of the present invention, in the direction of arrow "A" in Fig. l;
Fig. 3 is a section view of the appa-~tus of the present invention, taken along plane B-B of Fig. 2;
15Fig. 4 is an enlarged cross-sectional view of the attachment means and anchor means of the present invention shown in Fig. 3;
Fig. 5 is a view of an arrow 'c' of Fig. 4;
Fig. 6 is a pel~ re view of another embodiment of the appa,~lus of the present invention, in its intended-use position to shield, anchor, 20and contain a trailer home in gale-force winds; and Fig. 7 is an enlarged view on the area de~ign~ted as 'F' in Figs.
1 and 6 showing coupling means for joining sections of pelro~te sheet together.
Detailed Descli~ion of the Invention 25Figs. 1 and 6 show a perspective view of two different embo~im~nt~ of the ap~a~atus 10 and method of the present invention for securin~trailer homes and motor homes 12 (hereinafter mobile homes) against gale-force winds.
An oversized, substantially wind-permeable pelrolale sheet means 3014, capable of being cast or placed over the roof 16 of a mobile home 12, -is - 213;~05 conleml)lated as an essen~i~l component of the app~dlus 10 of the present invention. In the prert;ll~d embodiment, the pelroldle sheet means 14 is a flexible woven net, preferable formed of a water-resistant braided polyethylene.The surface area of the sheet means or net 14 of the present invention is greater than the combined surface area of the roof 16 and side walls 18 of the trailer home 12. This excess size is ill~ t, since a n~es~ry requirement of the invention is that net 14 when placed over the roof 16 of the mobile home be adapted to extend downw~rdly and also oulw~dly from the roof 16 at an acute angle a to the outer side walls 18 of the mobile home so as to create a protective inclined sloped surface 25 around each outer wall 18, as shown in Fig. 1, 2 and particularly Fig. 3.
In a plefe~led emboliment net 14 extends downwardly and outwardly so that the outer pe~ipht;l~l edge 20 thereof extends to at least the level of the lowermost portion 22 (floor) of the mobile home 12, so as to provide a protective inclined surface 25 proximate the entire surface of each outer wall 18 of the mobile home, as shown in Fig. 3.
Attachment means 24 are further provided, as shown in Fig. 1 and in greater detail in Figs. 4 and 5, ~tt~t~h~hle to the pelroldte sheet means 14 proximate the outer peripheral edge 20 thereof. Such attachment means 24 allow net 14 to be ~tt~hPd to ground anchor members 30 located in the earth surrounding the mobile home 12 (see Figs. 4 and 5), to thereby m~int~in net 14 in the angular outwardly extending position as shown in Fig. 3 around all outer sides 18 of mobile home 12. More particularly, it is desirous that the anchor means 30 be int~ cd about the periphery of mobile home 12, as shown in Figs. 1 and 2, and the ~im~nsinns of net 14 be such that net 14 is m~inhined at an outwardly extending angle c~ from the outer walls 18, as shown in Fig. 3. In a p~relled embodiment angle a so formed between the net and the outer side walls is between 15-60 and preferably between 20-35. Angle ~ should be a coll,promise between as high a value as possible to thereby afford as a "shock-absorbing" distance between net 14 and outer walls 18 to allow net 14 to protect walls 18 from airborne debris, while at the same time being as low a value as possible to thereby minimi7P. the size of the net means 14 required.
Since mobile homes are generally of sizes ranging from 30 ft. - 45 ft. in length (floor to roof), by 10 ft. in width, net 14 needs to be of a general rectangular shape of at least 30' x 50' (1,500 sq. ft.) for the .sm~llest trailer home size of 30' x 8' x 10', in order to have a protective in~`lin~ sloped surface 25extending outwardly and angularly downw~dly to protect subst~nti~lly all of the outer side walls 18 of mobile home 12 to the level of the floor 22 of the trailer home. Dimensions of this si7e will permit an angular slope o~ of net 14 of up toapproximately 30. Angle ~Y should be the greate~t value possible at which net 14 will extend with its peripheral edge 20 to a position level with the floor surface 22 of the mobile home, to thereby ensure walls 18 are entirely pro~led from horizontally-moving airborne debris.
Mobile home sizes greater than 30' x 8' x 10' require nets 14 of dimPn~ions larger than 1,500 sq.ft. if an angle ~ is to be m~int~ined and if peripheral edge 20 of net 14 is to extend to a level of floor 22 to thereby protect - all of the surface area of the outer walls 18 from impact damage due to airborne debris.
Notable, in order that net 14 when placed over the mobile home be adapted to extend evenly and uniformly downwardly and outwardly with a minimum of bunching and folding in a plerelled embodiment the pelroldte sheet means is comprised of two or more irregular shaped ~lr~ldte sheets or nets 14' joinable along various seems 40, as shown for example in Figs. 1, 2 and 7.
Accordingly, when a pelrolate sheet means 14 assembled in the prece~lin~ manner is placed over mobile home 12 and attached to the anchor means 30, a wrinkle and bunch-free sloped surface 25 is thereby formed proximate each of outer walls18 of mobile home 12, as shown in Figs. 1, 2 and 6.
To accomplish the joining of each of the various perforate sheets 14' which comprise entire net 14 releasable coupling means 42 may be utilized to join the pe,roldle sheets along a seam 40 thereof, as shown in Fig. 7. These - 213:~405 coupling means 42 may be of any type commonly known in the art, but in a pl~relred embodiment are a steel 'D'-shaped snap-ring.
Advantageously, releasable coupling means 42 along one or more seams 40 allows entry by a person in and out of the mobile home 12 when the appal~lus 10 of the present invention is assembled about the mobile home.
Notable, the force exerted by gale-force winds of up to 150-160 miles per hour, as was recently experienced in H--rrir~ne Andrew which struck the eastern seaboard of the State of Florida and some of the other states surrounding the Gulf of Mexico, including Louici~n~ in August 1992, can be quite ~ignific~nt.
Utilizing the formulas:
P = C x v2 and F = PxA
where: P is p~s~ul~ in lbs. force exerted on an area, C is a constant of 0.0027 x lb hr2 ft2mi2 (~sllming air at a specified density at standard te.l-pel~lure and pressure) V is velocity in miles per hour, and A is the surface area, the maximum force exerted by a wind of a given velocity against a perpendicularly-disposed outer wall 18 of a trailer home of a given area A can easily be calculated.
From Table 1, it can be seen that the force exerted by a gale-force wind of 160 miles per hour on a mobile home size of 45' x 8' (xlO') can exceed 24,000 pounds.
~131~U~
Table 1 Wind Speed (mph) Wall Size S P r e s s u r e of Mobile Force (lbs (lb/ft2) Home (ft2) 6.75 280 (35' x 8') 2430 6.75 360 (45' x 8') 9.72 280 (35' x 8') 3499 9.72 360(45' x 8') 13.23 280 (35' x 8') 4763 13.23 360 (45' x 8') 17.28 280(35' x 8') 6221 17.28 360 (45' x 8') 21.87 280 (35' x 8') 7873 100 21.87 360 (45' x 8') 27 280 (35' x 8') 9720 110 27 360 (45' x 8') 32.67 280 (35' x 8') 11761 120 32.67 360 (45' x 8') 38.88 280 (35' x 8') 13997 130 38.88 360 (35' x 8') 45.63 280 (35' x 8') 16427 140 45.63 360 (45' x 8') 52.92 280 (35' x 8') 19051 150 52.92 360 (45' x 8') 60.75 280 (35' x 8') 21870 160 60.75 360 (45' x 8') 69.12 280 (35' x 8') 24883 69.12 360 (45' x 8') 2~3~sos To resist a force of such m~nihlde applied by a 160 mile per hour wind perpendicularly cont~cting a wall of a mobile home, the net means 14 is affixed to suitable anchoAng means 30. It is cont~lnplated that anchor means 30 of the present invention be comprised of elong~t~, multi-helix screwable anchors30, which may be m~h~ni-~lly screwed into the ground (see Fig. 3).
A number of such anchor members 30 are commercially available.
One such product is multi=helix anchor manufactured by Dixie Electrical manuf~t~lring Company of Birmingh~m, ~l~h~m~, under Cat. No. D-284 for a tandem 8" helix anchor. According to information supplied by said co~llpany, such anchor ~lepen(ling on soil type and length of anchor, when inserted into the soil can resist a load of between 10,000 to 30,000 lbs. Using such information, knowing of the approp,iate soil conditions, the n~s~ry approximate spacing of such anchor means 30 around the periphery of a mobile home can be delell--ined to secure net 14 about a mobile home 12.
To avoid anchor means 30 protruding upwardly and creating a safety hazard, it is conle...plated in a p~re"~ embodiment that anchor means 30 be recessed below the surface of the earth, as shown in Fig. 3, 4 and 5. To f~r,ilit~t~. this, a r~ss~d well 70 may be further provided to su"ound anchor means 30, within which a cylindrical hollow canister 50 may be placed level withthe surface of the ground, as shown in Figs 3, 4 and 5. When anchor means 30 and appal~tus 10 of the present invention is not in use, a cylindrical cover plate (not shown) may be placed over the cylindrical canister 50, to thereby conceal and hide anchor means 30 from view.
Commercially available cylindrical canister devices 50 and cover plates suitable for such purposes are presently commercially available. For example, Brooks Products Inc., Polyplastic Division, of Cucamonga, California provides a "60 series Valve Box" which is ideally suited to this pu,~ose.
The ~tt~l~hment means 24 of the present invention may simply comprise a releasable attachment mçch~ni~m, such as a snap-ring, for releasably ~tt~rhing the net 14 at any point proximate the peripheral edge thereof directly to 213~40~
anchor means 30, as shown in Fig. 6. In a pferel~d emb~liment, however, it is conte,l-plated that the ~tt~hm~nt means 24 further comprise means for tight~n~l~ly securing flexible net 14 to anchor members 30.
Accordingly, it is further contelllplated that ~tt~hm~nt means 24 comprise a pair of releasably securable hooks 60, 62, one of which may be secured to anchor 30 and the other to net 14 as shown in Figs. 4 and 5. Rollablewebbing connects the two hooks 60, 62, and crankable tip=htenin~ means 70 is further provided to rollably wind the webbing 72 onto a spool 74, thereby bringing hooks 60, 62 together to thereby tighten net 14 to anchor 30, as shown in Figs. 4 and 5. An example of such a commercially available ti~htening means ideally suited to this purposes is model FE 400 (P/N802) Ratchet Strap, sold by Kenedyne Corporation of North Branch, New Jersey, having a breaking strength of 11,000 lbs., with a 2" cranking handle, and hooks 60, 62 interposed at each end.
An extremely lightweight and water resistant high-strength fibre particulary suited for net means 14 of the present invention is a braided line netting comprised of a polyethylene homopolymer having a high modulus of elasticity and a molecular weight of over 500,000. An example of such a commercially available fibre is SPECTRA~' manufactured by Allied Fibers, a division of Allied Signal Inc. of Petersburg, Virginia. In ~4 " single braid format, such fiber has a break strength of approximately 48,000 lbs., and a weight of approximately 22 lbs. per 100 ft. of rope.
EXAMPLES
1. Raschel Nylon Tension Tests In order to accurately model the impact of a projectile on the netting, data regardillg the stiffness and strength of the netting was obtained.
Trade Mark of Allied Signal Inc. for polyethylene twine and rope.
- 2~3~ 5 Simple static tension tests were pelrolllled, with load and strain data recorded at several points for each sample.
Sample Pr~)al~lion Specimens of nylon fibres were cut from a large section of netting.
A single strand (o.25 cm) of the netting was followed through a series of intersections. To avoid adverse effects on the test strand, intersection strandswere cut roughly five diameters away from the intersection. All cuts were made with a soldering iron to elimin~te unravelling. Typical sample lengths were 1.2 m.
To f~ilit~te gripping of the spe~im~n, and to ensure that failure occurred in the test section of the sample, the ends of each sample were threaded through the hollow core of a short length of 0.5 cm braided nylon rope. A clamp on the end of the rope nearest the test section, along with a knot a short distance away, elimin~ted the possibility of slippage of the specimen through the rope.
Experimental Procedure The test apparatus used was a Tinius-Olsen tension/colllpression test rig. Samples (inside the rope) were wound around a 4 cm dia. steel pipe) to avoid stress concentrations and tied off to a post. Elastic strands were ~tt~rlled to each sample at the end of the test section as references for strain measurements.
Typical crosshead separation rate was 20 mm/min. Deflections were manually measured at specific loads (e.g. every 4 Kg).
Maximum load ~uppolled by each sample was also recorded.
Results A typical plot of load vs. deflection is shown in Table 2.
- 2~31~
Table 2 Load (N) Strain (no. units) O O
49 0.09 0.15 140 0.20 175 0.24 225 0.27 260 0.28 310 0.30 355 0.32 400 0.33 2. Dropped Projectile Impact Tests Large samples of netting were tested for impact absorption capability through drop tests. The sample to be tested was securely fastened to a rigid frame, and a projective of measured weight and dim~nsions was dropped onto the specimPn from a range of measured heights.
Apparatus The netting used was 210/20 twine, (Hafner Fabrics, Toronto, Ontario Canada), 1.27 cm of stretched mesh 100% Nylon 6,6 (Du Pont) raschel - knit configuration. The raschel knit is a knotless configuration, with strands and intersections 'crocheted' together. The design~tion 210/20 indicates that 20 ends of 210 denier fibre form the yarn. The res--lting twine was roughly 1 mm in ~ m~ter. The mesh had a breaking strength of 25 kgs. and the mesh squares were roughly 6 mm wide.
Breaking strength is an indication of the net's capabilities.
Breaking strength is measured by pulling apart one square of the fini~hed product, so the element strength is half the breaking strength. Denier is a measure of a fibre's weight. One denier is equivalent to the weight in grams of a 9000 m length of the fibre. Thus, a 9000 m length of 210 denier fibre would weigh 210 grams. Stretched mesh size indicates the ~ t~nce between inte~ ions, along two sides of a square. Thus 1.27 cm stretched mesh colr~sponds to roughly 0.635 cm squares.
21~05 The raschel knit construction technique consists of es~P-nti~lly crocheting the yarns (three yarns together at a time) and forming loops in the net elPmPnt~. Intel~clions between elemPnt~ of the net are accomplished without knots; the crochet process continues through the int~,r~;lion, with one yarn being exchanged between the int~,~cling ele~ment.~. A main advantage of the raschel knit is its ability to stretch to a large degree: as much as 50% strain-to-failure for an element.
Another advantage of raschel is that, if one elPment of the net is damaged, there is no ten-lPncy for adjacent inlersections, or adj~cent el~Pm~-nts~ to unravel. This avoids single-point failures.
A third advantage is that intersections cannot slip signific~ntly, due to the exchange of yarns. Thus an opening can not be stretched wider by wind or impacts.
One more advantage is that no ~ignifit~nt strength is lost in inte~s~;~ions. Knotted netting configurations lose ~ignific~nt p~lroll-lance due to the stress concentrations of the knots.
A system for edge ~ttaçhmPnt was installed on each sample of netting to be tested. Earlier versions of this consisted of a rope or cable strung through the outside squares of the netting, the latter version consisted of a length of 5 cm webbing sewn onto the edge of the netting, with D-rings ~tt~t~he~ to this webbing using small 2.54 cm pieces of webbing A rigid frame, roughly 4 m square, was constructed from 10 cm angle iron to support the test samples. 2.5 cm eye bolts were attached to the inside corners and at the centres of each side of the frame. A 0.6 cm cable was strung through the eye bolts and tight~PnP-d with a turnbuckle. The netting was attached to this cable by stringing a rope between the edge attachment system and the cable every foot or so along the perimeter of the sample.
The degree to which the test specimen was stretched into place depended on the type of edge ~tt~chmPnt - the webbing allowed for very little 2~31405 stretch, whereas the rope strung through the edge allowed for ample pre-stressing (approximately 13.7%).
The projectile used was a still cylinder roughly 9 cm di~mPt~r, roughly 20 cm long, and 11.7 Kgs weight. As the projectile had fairly sharp S edges, tape was placed around the bottom edge to avoid cuffing the test specimen.
A ring was ~tt~ ed to the tope of the weight to support it from the crane.
Experimental Procedure The hook of a crane was placed above the centre of the net. A
rope was strung through the hook and ~tt~hed to the projectile. A tape measure attached to the hook was used to measure the height of the projective above the net. The projectile was dlopped from increasing heights until the net failed. A
video camera recorded all tests, and was used to measure displ~Rm~nt of the net,as indicated by a scale on the far side of the frame.
Results lS The maximum height from which a projectile could be dropped without d~m~ging the net ranged from 9.3 m (for the pre-stretched sample) to I0.21 m (for the unstretched sample), which col~s~nds to an impact energy of 1100 to 1200 Joules. The maximum displ~rem~-nt of the pre-stretched sample was approximately 1.0 m whereas the maximum displacement of the unstretched sample was approximately 1.3 m. The holes left by imp~t~ from a greater height were typically 20 cm in ~i~me~er. The force of impact was s~-fficient to do .~ignifi(~nt damage to the corner eyebolts. After the series of roughly lS tests, the eyes had been forced open, leaving gaps as large as 2 cm.
The nets were tested to failure. After the first intentional failure of the netting, several subsequent drop tests were pelroll"ed on the netting.
Results from these tests and direct observations in~ t~ that damage to the net was limited to the imm~i~te vicinity of the actual hole; outside a small lS cm distance away from the hole, the net ~l~o~l"ed as well as it had before being damaged.
3. Air Cannon Tests 21~1405 Impact tests were pe,rol-l-ed using a standardised air-propelled wood projectile at American Test Laboratory in Pompano Beach, Florida, U.S.A., to simulate hurri~ne force winds-windborne debris.
Apparatus Similar netting - Nylon 6,6 raschel knit, was used for this test as in the previous drop-tests. The edge attachment system used was a 5 cm webbing sewn around the edge of the samples, with D-rings att~hed with 2.54 cm webbing, spaced roughly 30 cm apart.
A bolted wooden frame of approximately 4 m square was used as part of the le~ ing means. 1.3 cm eye bolts were mounted through the wood at each corner of the frame and in the centres of the sides. 0.6 cm cable was strung through the eye bolts and tightened with a turnbuckle. Rope was used to attach the D-rings to the cable. Tension in the netting was low.
The cannon used to propel the projectile consisted of an air col--pressor, an air reservoir with a pressure gauge, a 10 cm air line, a manually activated bulle~lly valve, and a 10 cm PVC tube as a barrel of the cannon.
The end of the cannon was approximately 7.5 m from the flat, vertical stationaryplane of net.
The projectile was a 4 Kg, 5 cm x 10 cm x 2.4 m Southern Pine member having its front end slightly rounded. A 10 cm ~ m~ter disc was attached to the back end to provide a p~ess..le seal for the barrel of the air cannon.
Procedure Four tests were pe,rol-lled at increasing speeds: 65, 80, 90, and 100 feet per second (fps). Speed had been previously calibrated to reservoir pres~.lre at ples~u~s up to 80 fps, and an extrapolation was made from this datato calculate the pres~u~ required to provide the higher speeds. The tests were recorded on videotape and also provided the displacement of the netting during impact.
2131~0~-Results The net withstood the impact of the 5cm x 10 cm x 2.4 m rectangular wood projective at the aforesaid ~4cted three speeds of up to 90 fps, with net defo~ a~ion from its flat stationary plane of up to 1.1 m. At 100 fps, the net failed, leaving a 33 cm x 30 cm rectangular hole. Surprisingly, the eyebolts in each of the corners of the frame showed $ignifi~nt alteration in that their eyes had been prised opened and the bolt shanks bent by as much as 15 degrees. This in~ ~ted that the cumulative force of impacts of the four speeds had been si~nific~ntly large and had been transferred through the net material to each of the bolts. It should also be noted that the 90 fps test success indicates that the net is capable of with~t~n~ling more than three times the energy of thestandard impact test of 50 fps.
Similar air cannon impact tests with the 5 cm x 10 cm x 2.4m wood member conducted on 1.5 cm thick plywood and on 6 mm thick l~l-lpe ed and heat strengthened glass produced penetration of the plywood and breakage of the glass at 50 fps.
The degree of resiliency of the material e1enl~nt of the net was measured for two netting configurations: 210/20 nylon, and 18/80 polypropylene raschel. Maximum elongation for the nylon was roughly 34%, whereas the poly~r~ylene stretched as much as 50%. Tests showed that in one test an impact energy of approximately 800 joules on the above nylon 210/20 netting was readilyabsorbed by the net system while providing a displacement of approximately 0.7m. A 18/18 polypropylene net of 65% of the areal weight of nylon 210/20 also withstood the same impact of the wooden member at 20 m/s and provided a deformation of approximately 1 m.
Although the disclosure describes and illustrates plere.led embo limPnts of the invention, it is to be understood that the invention is not limited to these particular embo~im~nt~. Many variations and modifications will now occur to those skilled in the art.
Claims (21)
1. Means for shielding, anchoring and containing an object in the event of gale-force winds, comprising:
a substantially wind-permeable perforate sheet means of a surface area substantially greater than the surface area of said object and adapted for placement around said object and extendable downwardly and outwardly from the top of said object at an acute angle to the sides of said object;
a plurality of ground anchor members adapted for placement in the ground surrounding said object; and attachment means, attachable to said perforate sheet means along a periphery thereof, for securing said perforate sheet means to said ground anchor members.
a substantially wind-permeable perforate sheet means of a surface area substantially greater than the surface area of said object and adapted for placement around said object and extendable downwardly and outwardly from the top of said object at an acute angle to the sides of said object;
a plurality of ground anchor members adapted for placement in the ground surrounding said object; and attachment means, attachable to said perforate sheet means along a periphery thereof, for securing said perforate sheet means to said ground anchor members.
2. Means for shielding, anchoring and containing an object in the event of gale-force winds, comprising:
a substantially wind-permeable perforate sheet means formed of a resiliently flexible material and of a surface area substantially greater than the surface area of said object and adapted for placement around said object and extendable downwardly and outwardly from adjacent the top of said object at an acute angle to the sides of said object as to form at least one stationary, flat plane and so biased as to deflect or restrain windborne debris by absorbing the energyof impact of said debris on said sheet means by distribution of said impact energy throughout said material;
a plurality of ground anchor members adapted for placement in the ground surrounding said object; and attachment means, attachable to said perforate sheet means along a periphery thereof, for securing said perforate sheet means to said ground anchor members.
a substantially wind-permeable perforate sheet means formed of a resiliently flexible material and of a surface area substantially greater than the surface area of said object and adapted for placement around said object and extendable downwardly and outwardly from adjacent the top of said object at an acute angle to the sides of said object as to form at least one stationary, flat plane and so biased as to deflect or restrain windborne debris by absorbing the energyof impact of said debris on said sheet means by distribution of said impact energy throughout said material;
a plurality of ground anchor members adapted for placement in the ground surrounding said object; and attachment means, attachable to said perforate sheet means along a periphery thereof, for securing said perforate sheet means to said ground anchor members.
3. Means for shielding, anchoring and containing a trailer or mobile home in the event of gale-force winds, comprising:
a substantially wind-permeable perforate sheet means of a surface area substantially greater than the combined surface area of the roof and outer side walls of said home and adapted for placement over the roof and extendable downwardly and outwardly from said roof at an acute angle to said outer side walls of said home;
a plurality of ground anchor members adapted for placement in the ground surrounding said home; and attachment means, attachable to said perforate sheet means along a periphery thereof, for securing said perforate sheet means to said ground anchor members.
a substantially wind-permeable perforate sheet means of a surface area substantially greater than the combined surface area of the roof and outer side walls of said home and adapted for placement over the roof and extendable downwardly and outwardly from said roof at an acute angle to said outer side walls of said home;
a plurality of ground anchor members adapted for placement in the ground surrounding said home; and attachment means, attachable to said perforate sheet means along a periphery thereof, for securing said perforate sheet means to said ground anchor members.
4. Means for shielding, anchoring and containing a trailer or mobile home in the event of gale-force winds as claimed in any one of claims 1, 2, 3 or4 wherein said acute angle is in the range of 15° - 60° to said outer side walls.
5. Means for shielding, anchoring and containing a home in the event of gale-force winds as claimed in claim 3, wherein said perforate sheet means isadapted to extend downwardly and outwardly from said roof at an acute angle to each of said side walls of said home so as to substantially surround each of said walls of said home with a plurality of inclined perforate sheet surfaces.
6. Means for shielding, anchoring and containing a trailer or mobile home in the event of gale-force winds as claimed in any one of claims 1, 2, 3 or4 wherein said acute angle is in the range of 20° - 35° to said outer side walls.
7. Means for shielding, anchoring and containing said object or said home in the event of gale-force winds as claimed in any one of claims 1 to 6, wherein said perforate sheet means is a flexible net.
8. Means for shielding, anchoring and containing a home in the event of gale-force winds as claimed in claim 7, wherein said flexible net is comprised of a plurality of net members having peripheral edges, further comprising releasable coupling means to releasably couple two or more of said net members together along a respective peripheral edge.
9. Means for shielding anchoring and containing a home in the event of gale-force winds as claimed in claim 7, wherein said attachment means are releasable and further comprise means for tightenably securing said flexible netto said anchor members.
10. Means for shielding, anchoring and containing a home in the event of gale-force winds as claimed in claim 8, wherein said flexible net is comprised of a synthetic fibre, said fibre comprised of one or more of the materials selected from the group of polyolefines, polyesters and polyamides.
11. Means for shielding, anchoring and containing a home in the event of gale-force winds as claimed in claim 8, wherein said flexible net is comprised of a synthetic fibre, said fibre comprised of one or more of the materials selected from the group of polyethylene, polypropylene and nylon.
12. Means for shielding, anchoring and containing a home in the event of gale-force winds as claimed in claim 10, wherein said synthetic fibre is a polyethylene homopolymer having a molecular weight greater than 500,000.
13. Means for shielding, anchoring and containing a home in the event of gale-force winds as claimed in claim 10, wherein said synthetic fibre is a nylon 6,6.
14. Means for shielding, anchoring and containing a home in the event of gale-force winds as claimed in claim 8, wherein said flexible net is comprised of a nylon 66 in the form of a raschel crocheted knit.
15. Means for shielding, anchoring and containing an object in the event of gale-force winds as claimed in claim 8, wherein said flexible net is comprised of a polypropylene.
16. Means for shielding, anchoring and containing an object or a home in the event of gale-force winds as claimed in any one of claims 1-15, wherein said flexible net can withstand an impact energy of at least 500 Joules.
17. A method of simultaneously shielding, anchoring and containing an object in the event of gale-force winds, comprising the steps of:
casting an oversize substantially wind-permeable, flexible net means around said object so as to substantially cover at least one of the sides of said object, and attaching said wind permeable net means at or proximate an outer peripheral edge thereof to ground anchor means, so that said net means extends downwardly and outwardly from the top of the said object to an acute angel to the sides so as to surround a substantial portion of each of the sides with an inclined wind-permeable planar surface.
casting an oversize substantially wind-permeable, flexible net means around said object so as to substantially cover at least one of the sides of said object, and attaching said wind permeable net means at or proximate an outer peripheral edge thereof to ground anchor means, so that said net means extends downwardly and outwardly from the top of the said object to an acute angel to the sides so as to surround a substantial portion of each of the sides with an inclined wind-permeable planar surface.
18. A method of simultaneously shielding, anchoring and containing an object in the event of gale-force winds, comprising the steps of:
casting an oversize substantially wind-permeable, flexible net means over said object so as to substantially cover the top and sides of the said object, and attaching said wind permeable net means at or proximate an outer peripheral edge thereof to ground anchor means, so that said net means extends downwardly and outwardly from the top of the said object to an acute angel to the sides so as to surround a substantial portion of each of the sides with an inclined wind-permeable planar surface.
casting an oversize substantially wind-permeable, flexible net means over said object so as to substantially cover the top and sides of the said object, and attaching said wind permeable net means at or proximate an outer peripheral edge thereof to ground anchor means, so that said net means extends downwardly and outwardly from the top of the said object to an acute angel to the sides so as to surround a substantial portion of each of the sides with an inclined wind-permeable planar surface.
19. A method of simultaneously shielding, anchoring and containing a trailer home or motor home in the event of gale-force winds, comprising the steps of:
casting an oversize substantially wind-permeable, flexible net means over a trailer home or motor home so as to substantially cover at least one of the outer side walls of said home, and attaching said wind permeable net means at or proximate an outer peripheral edge thereof to ground anchor means, so that said net means extends downwardly and outwardly from the roof of said home at an acute angle to each of outer side walls of said home so as to surround a substantial portion of eachof said outer side walls with an inclined wind-permeable planar surface.
casting an oversize substantially wind-permeable, flexible net means over a trailer home or motor home so as to substantially cover at least one of the outer side walls of said home, and attaching said wind permeable net means at or proximate an outer peripheral edge thereof to ground anchor means, so that said net means extends downwardly and outwardly from the roof of said home at an acute angle to each of outer side walls of said home so as to surround a substantial portion of eachof said outer side walls with an inclined wind-permeable planar surface.
20. A method of shielding, anchoring and containing a home as claimed any one of claims 16-19, further comprising the step of tightenably securing said flexible net means to said ground anchor means.
21. A method of shielding, anchoring and containing a home as claimed in any one of claim 16-20, wherein said net means comprises a plurality of net members releasably coupled to each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002131405A CA2131405A1 (en) | 1994-09-02 | 1994-09-02 | Apparatus and method for securing an object against gale force winds |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002131405A CA2131405A1 (en) | 1994-09-02 | 1994-09-02 | Apparatus and method for securing an object against gale force winds |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2131405A1 true CA2131405A1 (en) | 1996-03-03 |
Family
ID=4154276
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002131405A Abandoned CA2131405A1 (en) | 1994-09-02 | 1994-09-02 | Apparatus and method for securing an object against gale force winds |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2131405A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107060458A (en) * | 2016-12-08 | 2017-08-18 | 天津大学前沿技术研究院有限公司 | A kind of flexible abat-vent |
| CN114046046A (en) * | 2021-12-02 | 2022-02-15 | 贾义心 | Green building installation and construction method based on BMI technology |
-
1994
- 1994-09-02 CA CA002131405A patent/CA2131405A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107060458A (en) * | 2016-12-08 | 2017-08-18 | 天津大学前沿技术研究院有限公司 | A kind of flexible abat-vent |
| CN114046046A (en) * | 2021-12-02 | 2022-02-15 | 贾义心 | Green building installation and construction method based on BMI technology |
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