This invention relates generally to the field of safety nets used in the construction of multi-storey buildings.
During the construction of multi-storey buildings, and in particular high rise office buildings, apartments and condominiums, it is often a legal requirement to install a safety net or other form of containment system about the exterior perimeter of a floor under construction to protect workers and equipment below from being struck by objects that may unintentionally drop or fall from floors above. Commonly, such safety nets are secured to post structures that span between adjacent floors and that effectively “hang” the nets in a somewhat horizontal configuration, extending outwardly from the side of the building. Objects that may become dislodged or otherwise fall from above can then be caught by the nets, preventing damage or injury to equipment or people below.
A variety of different safety nets have been developed for such applications. Conventional safety nets operate with varying degrees of functionality and efficiency. In each instance the netting material can at times be exposed to a considerable load, particularly if a relatively heavy object strikes it after falling from a significant height. To account for that loading, conventional safety nets are commonly secured to either two, or in some cases three, separate floors of the building under construction. The mechanical structure required to both support the safety nets and to accommodate the load to which it may be exposed can be significant and relatively complex, and can often be expensive and of a considerable weight.
There is a continual need to improve currently existing safety nets in order to enhance their functionality, increase the efficiency by which they may be installed and moved from floor to floor during the construction process, minimize their cost, and/or enhance the level of safety or protection that they provide.
The invention therefore provides a safety net for multi-storey building construction, the safety net comprising a first netting support secured to a plurality of floor engaging portions, each floor engaging portion having a support arm rotatably attached thereto; a second netting support secured to said support arms; and netting, secured to said first and said second netting supports such that rotation of said support arms causes said netting to move between a deployed and a stowed configuration, each support arm having a brace, when said netting is in said deployed configuration said brace extending between said support arm and its respective floor engaging portion such that the horizontal component of a load applied to said support arm is at least partially transmitted by said brace from said support arm directly to said respective floor engaging portion, resisting said netting moving to said stowed configuration.
In a further aspect the invention provides a safety net frame for a multi-storey building construction, the safety net frame comprising a plurality of floor engaging portions, each floor engaging portion having a support arm with a first end rotatably to said floor engaging portion such that rotation of said support arms relative to said floor engaging portions causes said frame to move between a deployed and a stowed configuration; a first netting support secured to said floor engaging portions; a second netting support secured to second opposite ends of said support arms; and a brace associated with each of said support arms, each of said braces having a first end rotatably secured to its respective support arm and having a second end releasably securable to a brace retainer on its respective floor engaging portion, said second ends of said braces disengaged from their respective brace retainers when said frame is in said stowed configuration; when said frame is in said deployed configuration said braces extending between said respective support arms and their respective floor engaging portions such that the horizontal component of a load applied to said support arms, is at least partially transmitted by said braces from said support arms directly to said respective floor engaging portions, resisting said frame moving to said stowed configuration.
In another aspect the invention provides a safety net for multi-storey building construction, the safety net comprising a first netting support secured to a plurality of floor engaging portions, each floor engaging portion having a support arm rotatably attached thereto, each floor engaging portion including an upper jaw having a floor engaging pin receivable within a detent in an upper surface of a floor structure, said pins resisting sliding movement of said upper jaws relative to the floor structure when said safety net is secured thereto; a second netting support secured to said support arms; and netting, secured to said first and said second netting supports such that rotation of said support arms causes said netting to move between a deployed and a stowed configuration.
The invention also provides a safety net for multi-storey building construction, the safety net comprising a plurality of floor engaging portions, each floor engaging portion having a support arm rotatably attached thereto, each floor engaging portion including an upper jaw engageable with an upper surface of a floor structure; for each floor engaging portion, at least one floor engaging pin receivable within a detent in the upper surface of the floor structure to resist sliding movement of said upper jaws relative to the floor structure when said safety net is secured thereto; a first netting support secured to a plurality of said floor engaging portions; a second netting support secured to said support arms; netting, secured to said first and said second netting supports; and a post for tensioning between the floor structure and an adjacent above floor structure, said post engageable with said upper jaw when tensioned in place between said floor structures to maintain said upper jaw in contact with the upper surface of the floor structure and to maintain said floor engaging pin within the detent.
Further aspects of the invention will become apparent from the following description taken together with the accompanying drawings.
For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings which show exemplary embodiments of the present invention in which:
The present invention may be embodied in a number of different forms. The specification and drawings that follow describe and disclose some of the specific forms of the invention.
With reference to
Safety net 1 is comprised of a first netting support 3 secured or otherwise attached to a plurality of floor engaging portions 4. Each floor engaging portion 4 has rotatably attached to it a support arm 5. In the embodiment shown in the attached drawings, support arm 5 has a lower end 6 and an upper end 7. As shown, lower end 6 is hingedly secured to its associated floor engaging portion 4 while upper end 7 is vertically higher (in use) than first netting support 3 and has secured to it a second netting support 8. Second netting support 8 will be secured to the upper ends 7 of a plurality of support arms 5 (see for example
In one embodiment, first and second netting supports 3 and 8 may be telescopic in nature to permit the overall length of the net to be extended (see
With specific reference to
It will be appreciated that first netting support 3, second netting support 8, floor engaging portion 4 and brace 11 will collectively form a safety net frame.
To permit safety net 1 to be moved between its deployed and stowed configurations, in one embodiment of the invention each of braces 11 has a first end 12 fixed and rotatably secured to its respective support arm 5. In the particular embodiment shown in the attached drawings first ends 12 are secured to support arms 5 by means of a stirrup connection 35 on brace 11 (see
Braces 11 include second ends 13 that are releasably securable to their respective floor engaging portions 4. Each floor engaging portion 4 may be fitted with a brace retainer, which in the depicted embodiment is a yoke 27 into which may be received second end 13 of brace 11. Yoke 27 is comprised of a pair of spaced apart flanges 50 having a lateral support 51 extending therebetween. End 13 of brace 11 may include a quick disconnect member 52 having a hook structure 53 receivable over lateral support 51 to releasably secure end 13 of brace 11 to floor engaging portion 4. In one embodiment, a lock 54 may be used to lock end 13 to yoke 27 and to prevent an unintentional disengagement of end 13 from floor engaging portion 4.
With first and second ends 12 and 13 of brace 11 secured to support arm 5 and floor engaging portion 4, respectively, brace 11 will serve to maintain support arms 5 at their desired spacing away from floor engaging porting 4 in the event that netting 9 were to stretch upon use or exposure to heat or sunlight. That is, should netting 9 stretch, without brace 11 secured in place support arms 5 would rotate downwardly oriented, adding to the possibility that an object caught by netting 9 may roll off the outer edge of the netting, potentially creating a safety hazard.
With reference to
End 13 of brace 11 may also include a shear pin 16 that secures quick disconnect member 52 to the end of brace 11. Under excessive loading (for example, through excessive force applied to netting 9 or by a high wind load borne by safety net 1) shear pin 16 will break along its shear zones to permit brace 11 to become disengaged from quick disconnect member 52 and hence floor engaging portion 4. Safety net 1 can then fold from its deployed toward its stowed configuration without bending or breaking under the force of the excessive loading. Where safety net 1 folds in such a manner on account of being exposed to high loading that results from a falling object, other than in exceptional circumstances the object will be retained within the netting as it folds. The load under which shear pin 16 will break can be designed according to the particular safety net and its operating conditions.
With the first ends 12 of braces 11 secured to their respective support arms, and second ends 13 of braces 11 secured to their respective floor engaging portions, safety net 1 will be in its deployed configuration such that a vertical load received by netting 9 (a “live” load) will be transmitted in the manner described above. Further, a horizontal wind load that may be borne by safety net 1 and/or support arm 5 will also be at least partially directed to the floor engaging portion 4 by operation of brace 11, reducing the load borne by other portions of safety net 1 and helping to prevent the net from unintentionally being moved to its stowed configuration. It will this be appreciated that the horizontal component of a load borne by support arm 5 will be transferred by its respective brace 11 directly to its respective floor engaging portion. By transferring wind loads and loads caused by falling objects directly to upper jaw 20, the establishment of a torque load on less robust aspects, or aspects that may be more susceptible to torque loading, of the floor engaging portion (and particular post 19, described below) is minimized. For example, in the embodiment depicted, brace 11 specifically transfers loading directly to upper jaw 20 and pin 23. In so doing the transferred load is borne by floor 2 with potentially damaging loads and/or torques directed away from other aspects or portions of the safety net, improving safety while also reducing the need (and hence cost and weight) of otherwise having to construct other portions of safety net 1 in a more robust manner. Orienting brace 11 in a somewhat horizontal configuration when in use also helps to more effectively transfer loading directly to floor 2.
To move a deployed safety net to its stowed position, the second ends 13 of braces 11 are disengaged from their respective floor engaging portions and allowed to drop downward by reason of first end 12 rotating within stirrup connection 35. The support arms can then be rotated upwardly into a generally vertical orientation (see
With particular reference to
Further, it will be appreciated that when safety net 1 is in its stowed configuration, with braces 11 disengaged from floor engaging portions 4, rotating support arms 5 outwardly to their deployed position will thus cause a sliding engagement of braces 11 with cable 17, the result of which will be a lifting of second ends 13 upwardly into position for re-attachment to their respective floor engaging portions. Cable 17 will also serve as a safety mechanism helping to prevent support arms 5 from rotating outwardly beyond a distance that is permitted by the length of cables 17, particularly when second ends 13 of braces 11 are disconnected from floor engaging portions 4.
In accordance with the invention, floor engaging portions 4 generally comprise a vertically oriented post 19 having slidably received thereon an upper jaw 20 and a lower jaw 21. Although lower jaw 21 may be slidably received about post 19, once the thickness of floor structure 2 is determined it is expected that lower jaw 21 will be fixed in position relative to post 19 through the use of a pin, bolt, etc. In the case of the embodiment shown in the attached drawings, upper jaw 20 preferably includes an actuator 22 to slidably move the upper jaw so as to bias the pair of jaws against the upper and lower surfaces of floor structure 2. In alternate embodiments, actuator 22 may be associated with lower jaw 21, or may be associated with each of the upper and lower jaws. Further, upper jaw 20 may include a floor engaging pin 23 that is received within a hole, recess or detent 45 in the upper surface of floor structure 2 when the upper and lower jaws are engaged thereabout. Detent 45 will in most instances be relatively shallow to minimize floor damage. When received within the detent, floor engaging pin 23 will resist sliding movement of upper jaw 20 relative to floor structure 2, and assist in preventing safety net 1 from becoming dislodged from about floor structure 2 when in use, and particularly when exposed to operational and/or wind loading. It will further be appreciated that a load transmitted through brace 11 to floor engaging portion 4 will be at least partially transmitted to and borne by floor engaging pin 23. In alternate embodiments (not shown), pin 23 could be situated on lower jaw 21 and/or on each of upper and lower jaws 20 and 21.
A particular embodiment of actuator 22 is shown in
As shown in
In an embodiment of the invention, floor engaging portion 4 may include a stabilizing arm 28 that extends downwardly at an angle from proximate the interior end of lower jaw 21 to intersect a vertical support 29 that extends vertically upward and generally parallel to post 19 from the lower portion of stabilizing arm 28 to a position proximate the outer end of lower jaw 21. Stabilizing arm 28, vertical support 29 and lower jaw 21 form a triangular structure. The lower portion of stabilizing arm 28 and the outer end of lower jaw 21 and/or the upper end of vertical support 29 may be fitted with sleeves 30 that are slidably received about post 19 to permit lower jaw 21 to be adjusted along the length of post 19 as necessary to accommodate floor structure 2. Bolts or pins can be inserted though sleeves 30 and post 19 to secure the sleeves in place. In an alternate embodiment sleeves 30 can be in the form of a single elongate tube received over post 19. In other embodiments vertical support 29 may be dispensed with.
It will be appreciated that the triangular structure of stabilizing arm 28, vertical support 29 and lower jaw 21 will help to prevent lower jaw 21 from tipping or becoming inclined relative to floor 2 during use of safety net 1. Should lower jaw 21 become tipped or inclined there could be the potential for floor engaging pin 23 to become dislodged from recess 45. The triangular structure will also help to maintain post 19 in a generally vertical orientation (particularly when safety net 1 is exposed to horizontal wind loading) and will also generally enhance the stability and structural integrity of floor engaging portion 4. In some instances, to further stabilize floor engaging portions 4 when secured to a floor structure, one or both of upper jaw 20 and lower jaw 21 may include stabilizing flanges 31 (for example, see
It will thus be understood that the utilization of safety net 1, constructed in accordance with the described invention, presents an ability to mount the safety net to a single floor of a building. This is in contrast to existing safety nets which typically require mounting to multiple floors, between adjacent floors, or that require the use of additional cabling, tie backs, etc. The described structure also presents an ability to easily move the safety net between its deployed and stowed positions and from one location to another.
The utilization of braces 11 significantly increases the structural rigidity of the safety net and enhances the load to which it may be safely exposed. The particular position of the connection of brace 11 to support arm 5, and the general horizontal orientation of brace 11 in use, helps to minimize torque on both support arm 5 and brace 11. The releasable connection of second end 13 of brace 11 to upper jaw 20 reduces torque loading on post 19, while the utilization of shear pin 16 presents additional advantages.
Cable 17 provides an ability to lift brace 11 into a position that permits a worker to easily and quickly re-secure the brace in place when the safety net is being moved from its stowed to its deployed configuration. The operation of upper and lower jaws 20 and 21 and floor engaging pin 23 facilitates the engagement and disengagement of the safety net with floor structure 2.
Safety net 1 can also be used in conjunction with more traditional edge protection, including one or more posts 26 which may be mounted adjacent to floor engaging portions 4 in instances where edge protection fencing, etc. is desired or required by law.
In some cases, lower jaw 21 may be dispensed with, and a post 26, extending between two adjacent floors, may be used to secure or hold upper jaw 20 in place (see
It is to be understood that what has been described are the preferred embodiments of the invention. The scope of the claims should not be limited by the preferred embodiments set forth above, but should be given the broadest interpretation consistent with the description as a whole.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2019/050058 | 1/16/2019 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2019/140521 | 7/25/2019 | WO | A |
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