NZ615336A - A fall arrester and method of installing same - Google Patents

Abstract

615336 A method of installing a fall arrester, for securing to a building frame in use, is disclosed. The fall arrester includes at least one pliable sheet (2) secured to a building frame (4, 4’) such that the sheet is elevated above ground level and spans between at least two wall sections of the building frame. The sheet is secured by trapping it between the top plate (5, 5’) of the wall frame and a packer plate (7, 7’) bearing downwardly against the top plate. By utilising the packer plate the user is able to advantageously assemble the fall arrester in place before construction of components of the building which require a worker to position themselves above the ceiling space. e building frame. The sheet is secured by trapping it between the top plate (5, 5’) of the wall frame and a packer plate (7, 7’) bearing downwardly against the top plate. By utilising the packer plate the user is able to advantageously assemble the fall arrester in place before construction of components of the building which require a worker to position themselves above the ceiling space.

Description

James & Wells ref: 134218DIV1/73 A FALL ARRESTER AND METHOD OF INSTALLING SAME STATEMENT OF CORRESPONDING APPLICATIONS This application is based on the Provisional specification filed in relation to New Zealand Patent Application Number 603000, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD The present invention relates to a fall arrester and method of installing same. In particular the present invention relates to a fall arrester to be secured to a building frame.

BACKGROUND ART There are inherent dangers to workers involved in construction of an elevated building structure, both in terms of falling from an elevated position and also being struck by falling objects or material.

Systems are known for use in preventing falls from the perimeter of an elevated structure, particularly multi-floor structures. For example, temporary safety barriers may be constructed around the periphery of a working area, or safety nets positioned around the exterior of the building.

However, known safety systems have several associated disadvantages. In particular, such devices only target the periphery of a working area rather than the working area itself. During construction it is common for frame work to be raised and secured in position, leaving elevated areas having gaps through which workers or objects may fall.

It has been proposed to position scaffolding within the interior of a building in order to create a temporary elevated surface to break the fall of a worker within the building. However, while the surface may be closer to the elevated position of the worker than the floor of the building the hard surfaces of the scaffolding remain an injury risk. Further, there are significant costs in the hiring or purchase of the scaffolding – along with the labour costs in assembling and disassembling it. Additionally, scaffolding on the interior of a building will restrict movement of workers on the lower level and may interfere with certain jobs being completed – adding to the complexity of project management and potentially delaying completion of the project.

It is an object of the present invention to address the foregoing problems or at least to provide James & Wells ref: 134218DIV1/73 the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a method of installing a fall arrester including at least one pliable sheet of material, the method including the step of: securing the fall arrester to a building frame such that the sheet of material is elevated above ground level and spans between vertical components of the building frame.

According to another aspect of the present invention there is provided a fall arrester, including at least one pliable sheet of material configured to be secured to a building frame such that the sheet of material is elevated above ground level and spans between vertical components of the building frame.

According to another aspect of the present invention there is provided a building including: a building frame including at least two vertical components; and a fall arrester, including at least one pliable sheet of material configured to be secured to the building frame such that the sheet of material is elevated above ground level and spans between the vertical components.

Preferably the sheet of material may be shaped according to the area within the exterior frame of the building in which the fall arrester is to be installed.

In doing so, it is envisaged that the amount of material required to manufacture the fall arrester James & Wells ref: 134218DIV1/73 may be reduced. Also, shaping of the fall arrester in this manner may assist in correct installation – the shape acting as a guide to the correct orientation of the fall arrester.

It should be appreciated that the sheet of material may extend beyond the area within the exterior frame, particularly in order to assist in fastening the sheet to the frame.

According to another aspect of the present invention there is a method of manufacturing a fall arrester, including: determining the dimensions of an area within an exterior frame of a building the fall arrester is to be installed in; shaping at least one sheet of material according to the dimensions of the area.

Reference to a fall arrester should be understood to mean a device configured to stop or check the passage of an object or person from an elevated position to a position below the device.

Preferably the fall arrester is sized and/or installed such that the sheet of material when installed sags less than substantially 800 mm across the span between the vertical components of the building.

It is envisaged that this may allow for a degree of deformation which assists in absorbing the energy of a falling object. Further, it is envisaged that this may reduce the likelihood of the sheet splitting due to impact on an overly tensioned sheet.

It should be appreciated that the exemplary value given for tension of the sheet above is not intended to be limiting, and may vary based on the dimensions of the installation and/or the material or structure of the sheet.

In a preferred embodiment the sheet of material may span the entire area between vertical components of the building frame.

In one embodiment, the fall arrester may include a plurality of sheets of material.

It is envisaged that in one embodiment these may be shaped to a particular building plan as discussed above. However, in another embodiment the plurality of sheets of material may be cut to size on site from a single piece – for example a roll of material.

The method of installing the fall arrester may include securing a plurality of sheets of material to the building frame such that sheets next to each other overlap along at least one edge.

It is envisaged that the present invention may have particular application to buildings constructed using a light frame construction method in which vertical structural members (namely wall sections) provide a frame to which interior and exterior wall coverings are attached, and support a roof made of horizontal ceiling joists and sloping rafters (or pre- James & Wells ref: 134218DIV1/73 fabricated roof trusses).

These wall sections typically include a series of vertical studs which are held parallel and at the desired spacing between wall plates – elongate frame members which extend horizontally across the top and bottom of the studs. The upper wall plate is commonly known the top plate, and may be referred to as such herein.

The wall sections of a building are commonly raised and fastened in place to the supporting platform of the building (for example a concrete foundation), with the remainder of the building constructed from this initial frame work. This may include ceiling and roof components which require workers to operate at elevated, and potentially unsafe, positions. As such, it is envisaged that the fall arrester may be installed following raising of the wall sections.

Preferably at least a portion of the sheet of material is positioned between at least two components of the building frame.

In particular, it is envisaged that the sheet of material may be positioned between the top plate of a wall section and another building component bearing against the top plate. For example, such building components may include ceiling joists or rafters spanning between walls, or packer plates used to provide spacing between such components and the top plate.

In doing so, the weight of those components may assist in securing the fall arrester in place – adding an additional level of security in preventing the sheet of material from slipping from the edges of the building when a worker or object drops onto it.

Further, by positioning structural components above the fall arrester workers may be provided with a working platform on which to support themselves and their equipment when navigating the elevated working position, rather than utilising the fall arrester for this purpose. While it is envisaged that the fall arrester system may be capable of providing such functionality, in some embodiments it may be desirable to discourage such behaviour to limit the likelihood of the sheet becoming damaged and potentially compromising it’s structural integrity.

Reference to the sheet of material being pliable should be understood to mean that the sheet displays fabric-like properties in terms of being capable of being easily bent, folded, rolled, or otherwise manipulated without plastic deformation.

Preferably the pliable sheet of material is made of polyethylene fabric. In a preferred embodiment the polyethylene fabric is made of a woven polyester base cloth, coated in polyethylene. This material is envisaged as providing a cost effective balance between weight and strength.

It should be appreciated that this is not intended to be limiting, and that the sheet of material may be made of any suitable material known to a person skilled in the art. For example, a PVC James & Wells ref: 134218DIV1/73 based fabric may provide greater strength and a greater lifespan, although such material would likely increase the cost of the system.

In another embodiment the sheet material may be made of netting, such as nylon netting.

Nylon netting may have the advantages of improved drainage in comparison with a woven or solid sheet, as well as having a structure suited to absorbing energy in a fall. However, in some embodiments it may be desirable to prevent penetration of sunlight through the fall breaker to provide shade, or reduce the likelihood of smaller objects such as nails or tools falling to the level below.

Preferably the sheet material is woven. Woven fabric is generally more flexible, and has a greater degree of give due to the ability of individual strands to move independently. It is envisaged that a woven sheet may resist being torn and/or penetrated by sharp objects, such as tools, which may be dropped onto the fall arrester. Tears may be stopped by the weave – hence the term “rip stop” being used in relation to some woven products. Further, while some strands may be damaged, others may be unaffected and maintain the woven pattern – thus retaining the strength of the material.

Preferably the fall arrester has sufficient strength to support a weight of up to substantially 90 to 100 kilograms.

It should be appreciated that this is not intended to be limiting, and that the fall arrester may be capable of supporting a greater weight. It should also be appreciated that other factors other than weight may affect the force applied by a falling object to the fall arrester.

However, it is envisaged that material costs may be saved by working to the likely weight of workers or objects the fall arrester may be used to prevent falling directly to the ground – rather than working to a higher specification.

Further, it is envisaged that a higher specification may require a heavier and/or thicker grade of material. This may have a negative impact on the transportation costs of the fall arrester, and make manipulation of the fall arrester more difficult during transportation and installation.

At later stages of construction, there may no longer be a risk of falling from an elevated position which requires the presence of the fall arrester. It is envisaged that the fall arrester may be easily removed from the building by using a cutting tool to cut the sheet of material around the interior of the building. It is envisaged that the time required to do so would present a significant cost saving in terms of labour requirements in comparison with alternative fall arresting technology such as scaffolding which requires dismantling of a separate framework.

In a preferred embodiment the fall arrester includes at least one aperture in the sheet of material.

James & Wells ref: 134218DIV1/73 It is envisaged that the aperture may act as a drain. In doing so, the collection of water by the fall arrester may be prevented during stages of construction in which a roof has not been positioned over the fall arrester. Otherwise, the weight bearing capacity of the fall arrester may be negatively affected. Further, pooled water may pose a safety hazard when using tools powered by electricity in the vicinity. Containers may be positioned to collect water and/or direct water flow out of the building.

Preferably the fall arrester includes a plurality of apertures positioned such that following installation the apertures are substantially in the centre of rooms within the building frame. In doing so it is envisaged that water flow may be directed to areas away from framework of the building. It should be appreciated that drainage apertures may not be provided for every room, although it is anticipated that apertures may be provided for rooms above a predetermined floor area.

Preferably the aperture includes reinforcement – for example an eyelet – reinforcing the sheet of material and reducing the likelihood of the sheet tearing at the aperture in the event of a worker or object falling on to the fall arrester.

The fall arrester may be secured to the building frame using any suitable means known to a person skilled in the art.

In one embodiment, the fall arrester may be secured using a fastener which passes through the sheet into the building frame – for example using one or more nails or nail-plates.

In another embodiment the fall arrester may include extensions such as straps, or attachment points to which such extensions may be secured. It is envisaged that these extensions may be adjustable in order to adjust the tautness of the fall arrester, or assist in reaching suitable attachment points on the frame.

BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: is a side view of an exemplary fall arrester system according to one aspect of the present invention; illustrates the floor plan of an exemplary building in which fall arresters may be installed according to various embodiments of the present invention is a top view of an exemplary fall arrester relative to the exemplary building James & Wells ref: 134218DIV1/73 according to an embodiment of the present invention, and is a top view of another exemplary fall arrester relative to the exemplary building according to an embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION illustrates a fall arrester system (generally indicated by arrow 1).

The fall arrester system 1 includes a pliable sheet of material 2 made of a woven polyester base cloth, coated in polyethylene. An aperture formed from an eyelet 3 is positioned in the sheet 2, and is configured to act as a drain as will be described further below.

The sheet 2 spans between two vertical components in the form of wall sections including studs 4 and 4’ and top plates 5 and 5’ respectively. The sheet 2 is positioned such that the lowest point (d) of the sheet 2 relative to the level of the top plates 5 and 5’ is no greater than 80cm.

The sheet 2 is secured in place by hammering nails 6 and 6’ into the studs 4 and 4’ respectively. In the embodiment illustrated, packer plates 7 and 7’ are positioned to bear against the top plates 5 and 5’ – sandwiching the sheet between them. Additional fasteners (not illustrated) may be passed through the packer plates 7 and 7’ at points 8 and 8’ into the sheet 2 and top plates 5 and 5’. Rafters 9 and 9’ may then be placed on top of packer plates 7 and 7’, along with other structural members of the roof structure.

It should be appreciated that alternative or additional structural members such as joists (not illustrated) may be positioned above the sheet 2 and used to secure the sheet 2 in place. illustrates a floor plan of an exemplary building 20 in which the fall arrester of the present invention may be implemented.

In , an uninstalled exemplary fall arrester is illustrated using dashed lines 21. It may be seen that the fall arrester 21 includes a single sheet has been shaped to substantially align with that of the building 20. In the embodiment illustrated, extended areas (such as that illustrated by diagonal hatched area 22) have been included in order to assist in securing the fall arrester 21 in place in the manner illustrated by On installation, the fall arrester spans the entire area between walls of the building 20.

The fall arrester 21 includes a number of eyelets, such as eyelet 23, positioned to substantially align with the centre of the larger rooms within the building 20. The fall arrester 21 is likely to sag to its lowest points at these positions, and the eyelets 23 prevent the pooling of water at these points.

James & Wells ref: 134218DIV1/73 illustrates an alternative configuration of a fall arrester including a plurality of sheets – including sheets 24 and 24’. The sheets may be cut sequentially from a roll of material and secured in position spanning between two walls of the building 20.

In order to prevent falling workers or objects dropping directly between the sheets 24 and 24’, they are installed in an overlapping fashion (as illustrated by hatched area 25). While a worker may still pass between the sheets 24 and 24’, their fall will be checked and the risk of injury reduced.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.