Patent Application
20060272892
This invention relates to an anchor assembly for one or more safety devices and more particularly, to an anchor assembly for securing one or more safety devices to a structure such as a building.
The building industry is becoming evermore conscious of the need for ensuring the safety of its workers and, indeed, authorities in many jurisdictions have introduced, or are in the process of introducing, recommendations and regulations which seek to make building sites and buildings on which workers must perform their duties safer workplaces.
It has long been recognised that a primary cause of injuries, particularly to inexperienced workers, arises from falls from elevated building structures resulting sometimes in severe injury or even death. Prior art methods of addressing this problem include the mounting of temporary rails around the periphery of roof areas and the fixing of personal safety harnesses and ropes to anchor points, such as exposed rafters, etc. Whilst the rails may be helpful in most situations, there remains the possibility that an unsecured worker may still topple over the railing. Anchor points, such as those which may be mounted on exposed beams or rafters, may not be satisfactory as the structural members themselves may not be capable of sustaining the loads necessary to withstand the damage resulting from the impact occasioned by the fall of a worker. Moreover, such falls will end in a severe jolt to the worker when the full extent of the rope or cable is taken up, which may itself occasion injury.
It is therefore an object of the invention to ameliorate some or all of the foregoing problems and at the very least the invention provides an alternative to proposed anchor assemblies for safety devices.
Accordingly, in one broad form, the invention provides an anchor assembly for securing at least one safety device indirectly to a structure, the anchor assembly including:
a) at least two spacers, including a first spacer and a second spacer;
b) at least one bridging member spanning between the spacers; and
c) engagement means for securing the safety device to the anchor assembly,
wherein each spacer includes:
d) securing means for securing the spacer directly to the structure;
e) a head for fastening the spacer to the bridging member and/or to the engagement means; and
f) a shaft extending between the securing means and the head,
wherein the shaft of at least the first spacer is adapted to deform progressively (ie in a prescribed manner) so as to at least partially absorb the kinetic energy applied by a load of a falling object attached to the safety device. Preferably the deformation will occur progressively along the length of the shaft of the spacer starting from below the head and moving towards the securing means. In this way the initial load on the structure is minimised, so that by the time the force reaches the securing means it has been significantly reduced, thereby resulting in less damage to the structure or any roofing material etc associated therewith. Furthermore, the deformation thus caused is visible and serves as an indication that the anchor assembly should be replaced, having been thus used.
The structure may include a building structure. The building structure may be in the process of being built, or may be the subject of maintenance or renovation activities. The building may be a commercial or domestic structure and the invention is applicable to any type of roof covering, requiring only that it is possible to gain access to structural members to which the anchor assembly may be affixed. Such structural members include purlins, structural beams and the like.
The safety device may include a range of devices adapted to secure a worker or an object, particularly against the likelihood of falling. The safety device may include a railing or cable. The safety device may include a railing or cable to which a safety harness is coupled by means of a runner or shuttle so as to allow the safety harness to move along the length of the rail or cable. In such embodiments the anchor assembly as described herein will preferably be an end anchor, that is to say the railing or cable will terminate at the anchor assembly. However, the anchor assembly may be used as an intermediate anchor point through which or by which such rail or cable passes so as to support same, especially at points where additional load bearing capability is required over and above that provided by a simpler unitary anchor device. It will be understood that in such instances the shuttle may be so designed as to provide a pass through action so that the shuttle can pass through the anchor point without having to be disconnected from the rail or cable.
In any event, in any of these arrangements involving a rail a cable, the anchor assembly of the invention will preferably cooperate with one or more other anchor assemblies or simpler anchor devices located along the length of the rail or cable they support, each other such anchor assembly or simple anchor device cooperating to distribute the load and preferably also each having the means to progressively deform as described above in relation to the spacer, to absorb the load. On the other hand, the safety device may include a safety harness affixed directly to a single anchor assembly, such as by a rope or cable.
The spacers, including the first and the second spacer, may be adapted to space the bridging member from the structure, such as a purlin or other roof structural member. The first and second spacers may be identical or different. The first and second spacers may be of equal length, in which case the bridging member will be spaced uniformly, that is to say spaced generally parallel to the surface of the structure to which the anchor assembly is attached or they may be of different lengths in order to space the bridging member at an angle with respect to the surface of the structure. Preferably, the first and second spacers are adapted to provide substantially uniform spacing between the bridging member and the structure.
The securing means for attaching each spacer to the structure includes a variety of means including all known positive engagement means applicable to the invention. For example, the means of fastening may include a clamp. Alternatively, the means of fastening may include a simple threaded bolt and nut arrangement. Preferably, the shaft of the spacer terminates at its lower portion in a threaded bolt. The threaded bolt may be adapted to extend through or into the structure and be threadably engaged therewith. More preferably, the threaded portion may be adapted to extend through the structure and be secured by an element with a corresponding internally threaded bore, such as a retro block, so designed for that purpose. The threaded portion may be secured additionally on the side of the structure from which the shaft extends by a further threaded element, such as a nut. Preferably, the further nut is a cone locknut with a tapered skirt depending from the nut body. The tapered skirt may provide the spacer with added energy absorption capability by progressively deforming as the deforming shaft bears against its internal wall upon application of sufficient load.
The shaft of the first spacer, and optionally the shafts of the one or more other spacers, including the second spacer, may be resiliently deformable whereby, after removal of the load, the shaft returns to its original pre-load position. Preferably however, the first spacer shaft is adapted to deform plastically, whereby it does not return to its original shape after the removal of the load. Preferably, the second spacer shaft is adapted to also deform plastically. Preferably, the shafts of all of the spacers are adapted to deform plastically.
The first spacer shaft is preferably tapered. The first spacer shaft may be tapered such that the shaft region nearest the securing means for the spacer is relatively wide in diameter and the shaft portion nearest the bridging member (ie the towards the head) is narrower in diameter corresponding to a neck portion. The neck portion may include a short section nearest the head which expands in diameter up to the point where it meets the head portion, such that the section of narrowest diameter is intermediate the length of the first spacer shaft. Similarly, each of the other spacer shafts may be tapered in like manner as described herein.
The first spacer shaft may be solid in structure. The first spacer shaft may be hollow or tubular in structure. The spacer shafts of the other spacers may optionally be solid or hollow.
The head of the first spacer may include any means standard in the art suitable for securing the bridging member and/or the engagement means to the spacer. For example, the first spacer head may include an internally threaded bore for receiving a correspondingly threaded bolt. The second spacer head and/or other spacer heads may be similarly configured. Alternatively, the second spacer head may include a threaded bolt adapted to co-act with a correspondingly threaded nut. The bridging member may be secured to the second spacer head by applying locknuts either side of the bridging member such that the bridging member is situated intermediate the head of the second spacer and lying in a plane transverse thereto.
The bridging member may include an elongate plate with holes spaced along its length to receive threaded bolt portions. For example, where only a first and a second spacer is used according to the invention, the bridging member may be about 0.5 meters long and have an aperture either end for receiving the first and/or second spacer. However the bridging member may be any desired length. The bridging member may also be adapted to resiliently deform upon the application of the load. Alternatively, the bridging member may be adapted to deform plastically. The bridging member may include one or more weakened portions which preferentially deform to absorb kinetic energy arising from the load. The bridging member may include or consist of fluted or corrugated features or the like to this effect. In the alternative, the bridging member may be rigid and adapted to maintain the separation between the first and second and any other spacers to which it affixed.
The engagement means may merely include a feature adapted to engage the safety device. For example, the engagement means may include a simple eyelet. The engagement means may include a base adapted to be fastened to the head of one or other of the spacers. The engagement means may include an engagement device for fastening the safety device to the anchor assembly. For example, the engagement device may include a screw fastener, eyelet or closable hook as may be found in grappling, abseiling or boat rigging gear, or other suitable coupling device. The engagement means may include a shaft extending between the base and the engagement device. With particular advantage, the engagement means may be provided in the form of a plate having a generally “s-shaped” configuration as described below in more detail in the drawings to provide additional resilient support.
Where an eyebolt or the like is employed, the shaft of the engagement means may be of a similar construction to the shaft of one or more of the spacers. The shaft of the engagement means may terminate at its base in a threaded bolt portion. The threaded bolt portion may be adapted to threadably engage the internal bore of the head of a spacer having such a facility. Alternatively, the engagement means may terminate at its base with an internal threaded bore located therein, which mates with a correspondingly threaded bolt portion forming the head of the spacer.
The first and second spacers may be adapted to receive first and second engagement means, respectively. Extending between the respective engagement devices of the first and second engagement means may be an extension member. The extension member may be in the form of a beam or elongated plate adapted to be engaged with each of the engagement devices and may itself include engagement means whereby to secure the safety device. This may be an additional engagement means to any that are associated with respective spacers, or may be utilised in place of engagement means associated with such spacers. The extension member may yet be another means of absorbing or distributing the load applied to provide gradual deceleration to the object attached to the safety device should the object fall, ie to provide additional progressive deformation. With particular advantage, the extension member may be a turnbuckle, which may be utilised to maintain appropriate tension between the components, especially when the anchor assembly is used to support a cable, which preferably should be maintained under tension. Where a cable or rail is utilised, that may also be attached to the anchor assembly by means of a turnbuckle to allow adjustment in the tension thereof.
As the person skilled in the art will appreciate, the energy absorbing anchor assembly of the invention may include a variety of combinations of the various above described components, depending on the application and the anticipated load to which the anchor assembly may be subjected. For example, one particular arrangement might allow for the cable to change direction, eg near the corner of a roof etc, and can be achieved by having a suitable arrangement of components interconnected as described herein, but rather than being in linear arrangement, may for example extend at right angles so that a cable can pass through a pair of suitable engagement means in the form of eyebolts or the like, which are located on arms extending perpendicularly. With the application of appropriate tension within and on the anchor assembly, the cable or rail can be made to form an arc between the engagement means. Alternatively, where the cable itself is not sufficiently rigid, it can be made to pass through an arcuate sleeve to provide the necessary rigidity. This is particularly useful in applications where a shuttle connecting the safety harness to a user is employed to travel along the cable and it is desirable to allow the user to move in more than one direction.
The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
In the drawings:
Turning to
The shaft (13), being made of 316 stainless steel, is able to withstand minor loads consistent with the tugs and pulls to be expected from the application of a workman in harness (affixed elsewhere to the engagement means as described below) carrying out normal work duties. However, should the worker fall and place his full weight on the anchor assembly of which this spacer (10) is a component, if this is the first spacer, it will tend to deform first at the neck (15) and, depending on the size of the load, progressively deform down to the wide base (14) plastically such that no rebound is caused by this spacer (10) or the total anchor assembly.
Referring to
With reference to
Referring generally to FIGS. 8 to 14, identical reference numerals are used in relation to those components previously described above. With specific reference to
The threaded lower bolt portion (41) of eyebolt (40) is threadably engaged into the hollow head (12) of spacer (10) and the bridging plate (50) is located immediately above and in abutment to the top surface (16), the lower threaded portion (41) intersecting the aperture (57a) of the bridging member (50). The bridging plate (50) is secured in place by the agency of a second cone locknut (70) which sandwiches the bridging plate (50) between the top surface (16) of the spacer (10) and the nut portion (72). The opposite end of the bridging plate (50) is secured by the agency of a pair of hexagonal locknuts (82) which sandwich the bridging plate (50) in between, the threaded head (22) of the second spacer (20) being in registry with the second aperture (57b) of the bridging plate (50).
In practice, it can be seen that a safety device (not shown) may be secured to the eyebolt head (42). Upon the application of a significant load caused by the falling of an object (not shown) moment transverse to the longitudinal axis of the eyebolt (40) will be applied to the eyebolt head (42) whereby the shaft (43) will begin to plastically deform, first at the neck (45) and progressively down to the cone locknut (70) which will also plastically deform. Depending on the amount of force involved, the tapered shafts (10, 20) of the first and second spacers (10, 20), the cone locknuts (70) and the bridging plate (50) may also plastically deform in a progressive manner to absorb the kinetic energy applied by the load of the falling object attached to the safety device.
In
Turning to FIGS. 15 to 17 there is shown an alternate engagement means 151 in the form of a plate bent in an s-shaped configuration when viewed side-on. It has been found that such a plate provides additional advantages when used in an anchor assembly for example as shown in FIGS. 16 or 17. The parts already described above are again referenced with the same numerals. An attachment means 152 for a cable 153 is utilised, which in the case of
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003905610 | Oct 2003 | AU | national |
This application is a continuation of International Application No. PCT/AU2004/001405, filed Oct. 14, 2004, which was published in the English language on Apr. 28, 2005, under International Publication No. WO 2005/037378 A1 and the disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/AU04/01405 | Oct 2004 | US |
| Child | 11279656 | Apr 2006 | US |
