AU2008100234B4 - Static line shock absorber - Google Patents

Abstract

The present invention provides a static line shook absorber including a shock absorbing plate which is adapted to be secured to a mounting plate by means of an anchor bracket, and preferably attached to the end of a static line cable, whereby the static line shock absorber provides an effective means for breaking or slowing a person's fall in a fall arrest situation, a body housing portion which is adapted In the form of an outer and inner cover plate for enclosing and protecting the shock absorbing plate against accidental deployment and a toggle strap, standard pin and retainer clip which are adapted to attach the shock absorbing plate to an anchor bracket.

Description

Regulation 3.2 AUSTRALIA Patents Act 1990 'INNOVATION SPECIFICATION APPLICANT: Roland Stephen Voss NUMBER: FILING DATE: INVENTION TITLE: STATIC LINE SHOCK ABSORBER The invention is described in the following statement : - -2- STATIC LINE SHOCK ABSORBER Field of the Invention S The invention relates to fall protection and arrest systems and associated components, and in particular, to a static line shock absorber which can provide an effective means for slowing and breaking a person's fall in a fall arrest situation, whilst working at heights or on a roof having any profile or configuration. The invention moreover features a unique design whereby the shock absorber can prevent accidental 10 deployment by a user and consequent slackness in the static line cable tension, and provides safety indication when no longer suitable for use. Whilst the invention may be integrated with other components of a static line system which is required to be permanently attached to a roof, for convenience sake, the 15 invention shalI be described herein in terms of a static line shock absorber for securing to a mounting plate or anchor bracket. Background to the Invention 20 Most fall protection and arrest systems may employ the use of a shock absorber which is integrated into a static line system for absorbing the energy resulting from a person's fall. The standard type of shock absorber incorporates helical springs and/or other elements which are adapted to deploy and extend or distort, thereby absorbing the energy generated by a user exerting a pull on a static line cable. The main 25 disadvantage of these and other current shock absorbers is that they are prone to deploy prematurely, as a result of normal work being carried out at heights or on a roof (ie. contrary to their primary function of absorbing energy generated during fall arrest), thus causing a potentially dangerous situation attributable to slackness in static line cable tension. 30 Whilst there have been some design developments in improved types of shock absorbers, whereby deployment is only possible once a pre-set load has been reached, they fail to provide an effective means for both locking the shock absorber in place until that stage, and for indicating occurrence of a fall arrest situation which 35 renders the shock absorber no longer suitable for use.

-3 Accordingly, it would be advantageous of at least some of the embodiments of the present invention to overcome or substantially ameliorate the disadvantages of the prior art, by providing a static line shock absorber which incorporates an effective means for slowing and breaking a person's fall in a fall arrest situation, and for 5 indicating when the shock absorber is no longer suitable for use. Moreover, by providing a shock absorber which prevents accidental deployment by a user and consequent slackness in static line cable tension, Any reference herein to prior art is not intended to imply that such prior art forms or 10 formed a part of the common general knowledge in Australia or any other country. Summary of the Invention 15 In one aspect, the present invention provides a static line shock absorber including: a shock absorbing plate which is adapted to be secured to a mounting plate by means of an anchor bracket, and preferably attached to the end of a static line cable, whereby the static line shock absorber provides an effective means for slowing and breaking a person's fall in a fall arrest situation; and 20 a body housing portion which is adapted in the form of an outer and inner cover plate for enclosing and protecting the shock absorbing plate against accidental deployment; and a toggle strap, pin and retainer clip which are adapted to attach the shock absorbing plate to an anchor bracket. 25 The shock absorbing plate has provided a plurality of shock relief cuts and holes adapted in alternating positions along the respective top and bottom edges, such as to absorb the energy generated by a person's fall when deployed in an axial direction, without allowing the metal material to split or fracture completely at any particular 30 point. The shock absorbing plate is preferably adapted to be at least partly painted with a safety rated colour, to indicate its unsuitability for use after being extended as a result of deployment in a fall arrest situation. 35 The shock absorbing plate has provided two locating slots for aligning with and receiving the two locating lugs of the body housing portion outer cover, and adapted as a unique locating feature for preventing distortion below a pre-set safe working force limit, resulting from an accidental pull exerted by a user, thereby maintaining the 5 pre-set static line tension. The outer cover plate has provided two locating lugs aligned for being received into the two locating slots of the shock absorbing plate, and adapted as a unique locking feature for maintaining the static line tension pre-set by means of an in-line tensioner. 10 The toggle strap is preferably a unique pre-formed member adapted to receive a standard integral pin shank and head therethrough at its open end, secured by means of a standard retainer clip, 15 In a second aspect, the present invention provides a static line shock absorber for providing an effective means for slowing and breaking a person's fall in a fall arrest situation, the static line shock absorber including: a shock absorbing plate adapted to be secured to a mounting plate by means of an anchor bracket, and attachable to an end of a static line cable, the shock 20 absorbing plate comprising: a plurality of shock relief cuts to extend the shock absorbing plate to an extended position in the fall arrest situation- and a plurality of shock relief holes located relative to the plurality of shock relief cuts to absorb and dissipate the energy generated by the person's fall. 25 In one form, the shock absorbing plate can further comprise a body housing portion comprising an outer and inner cover plate for enclosing and protecting the shock absorbing plate against accidental extension. 30 The shock absorbing plate can have provided two locating slots for aligning with and receiving two locating lugs of the body housing portion, and adapted as a locking feature for preventing extension of the shock absorbing plate below a pre-set working force imit, resulting from an accidental pull exerted by the person, thereby maintaining static line tension pre-set by means of an in-line tensioner. 35 5 In one form, the shock absorbing plate can be adaptable to be at least partly painted with a safety rated colour, to indicate its unsuitability for use after being extended in the fall arrest situation. 5 In order that the invention may be more readily understood, we will describe by way of non-limiting example of a specific embodiment thereof. Brief Description of the Drawing Figures 10 Figure 1 shows a perspective view of the static line shock absorber secured to a mounting plate by means of an anchor bracket, according to a preferred embodiment of the invention in a closed or unextended position. Figure 2 shows assembled and exploded views of the static line shock absorber 15 according to a preferred embodiment of the invention in a closed or unextended position. Figure 3 shows a perspective view of the static line shock absorber toggle strap, pin and retainer clip according to a preferred embodiment of the invention. 20 Description of a Preferred Embodiment of the Invention Figures 1 to 3 show a unique static line shock absorber according to a preferred embodiment of the invention. 25 The shock absorber 1 is preferably made of a metal material such as austenitic stainless steel grade 304. However, it is envisaged that any other suitable material may be adopted provided that it is strong and robust, durable and resilient, weather resistant and non-corrosive, has inherent shock absorbing capabilities and| meets the 30 requirements of the invention for outdoor applications. In this preferred embodiment, the present invention features a static line shock absorber 1 which provides an effective means for slowing and breaking a person's fall in a fall arrest situation, whilst working at heights or on a roof having any profile or 35 configuration. The shock absorber 1 shall be described herein as a unique stand alone component which is adapted to be integrated into a static line system. However, it is -6 envisaged that the invention may also be mounted vertically where required, and/or adapted to be attached to any other compatible component of a static line system. It is envisaged that the shape and/or dimensions, style and/or features of the shock absorber and/or its components may be varied as required to suit different static line 5 systems and/or other applications. A static line system preferably has provided at least one shock absorber which is adapted to be secured to a mounting plate by means of an anchor bracket, and preferably positioned at an end of a static line cable. The shock absorber 1 preferably 10 has provided a unique body housing portion 10 which is adapted to be in the form of an outer 11 and an inner 12 cover plate. In a preferred embodiment the body housing portion 10 is preferably rectangular in shape. However, it is envisaged that any other suitable shape may also be employed. The body housing portion 10 is preferably adapted and formed so that it can receive and protect a shock absorbing plate 20 15 therein. The shock absorber 1 preferably has provided a shock absorbing plate 20 which is adapted to be located within the body housing portion 10 and is extendable between the first closed or unextended position and a second open or extended position. The 20 shock absorbing plate 20 is preferably adapted to be at least partly painted with a safety rated colour, such that when the plate is extended (such that the body housing position 10 is removed or that the shock absorbing plate 20 is extended beyond the body housing portion) the coloured portion (not shown) will be exposed to indicate that the shock absorber 1 is no longer suitable for use. 25 The shock absorbing plate 20 has provided a plurality of shock relief cuts 21 which are adapted to allow the shock absorbing plate 20 to extend in a manner which will slow and break a person's fall from a height or roof surface. The shock relief cuts 21 are preferably adapted to extend at ninety degrees inwards from both top and bottom 30 edges along a substantial width of the shock absorbing plate 20, such that the plate can be pulled open and distort axially at the shock relief cuts 21. The shock relief cuts 21 are preferably adapted to be positioned in an alternate arrangement, such that every second shock relief cut 21 will be along the top edge 22 of the shock absorbing plate 20 and every other shock relief cut 21 will be along the bottom edge 23 35 respectively. Provided at the inner end of each shock relief cut 21 is a unique shock relief hole 24, which is preferably a circular hole adapted to ensure that the shock -7 absorbing plate material will only be pulled open and distort axially to a certain limit, without allowing the material to split or fracture completely at any particular point. This alternating arrangement of shock relief cuts and holes positioned along the 5 respective top and bottom edges of the shock absorbing plate, is preferably adapted to extend axially in a zig-zag patten as the shock absorber is deployed to absorb and dissipate the energy generated by a person's fail. The shock absorbing plate 20 may preferably have two apertures provided at its 10 extremities, differing in both shape and dimension. A first aperture 25 provided at the radiused end of the shock absorbing plate 20 is preferably in the form of a circular hole, which is adapted to receive the swaged end of a static line cable. A second aperture 26 provided at the straight end of the shock absorbing plate 20 is preferably in the form of an elongated hole, which is adapted to receive a toggle strap 40 and pin 15 41 for attachment to a mounting plate by means of an anchor bracket. The dimensions of the two apertures 25 and 26 are such as to permit adequate tolerances for articulation of the respective static line cable end and toggle strap. However, it is envisaged that any other suitable configuration may also be employed. 20 The toggle strap 40 is preferably in the form of a unique pre-formed member adapted to pass through the elongated hole 26 at the straight end of the shock absorbing plate 20. The toggle strap 40 has two holes 42 at the open end for receiving the pin 41 therethrough. The pin 41 preferably comprises an integral pin head 44 and shank portion 43, which is adapted to be passed through the two holes 42 on the toggle strap 25 40 and the corresponding pin hole 46 on a mounting plate anchor bracket. The pin 41 is preferably held in place by means of a retainer clip 45 or any other suitable securing means. The shock absorbing plate 20 preferably has provided two rectangular locating slots 30 27 adapted to receive the two locating lugs 28 of the body housing portion 10 outer cover plate 11. However, it is envisaged that any other suitable configuration may also be employed. The locating slots 27 are preferably adapted to be positioned between the respective shock absorbing plate apertures 25 and 26 and the extreme outer shock relief cuts 21, and aligned such that the locating lugs 28 provided on the outer 35 cover plate 11 can be received into the corresponding two locating slots 27 provided on the shock absorbing plate 20. The locating lugs 28 effectively provide a unique -8 locking feature for the shock absorbing plate 20 within the body housing portion 10, thus preventing an accidental pull exerted by a user, via a safety restraint harness gear (not shown), from distorting the shock absorbing plate below a pre-set safe working force limit. Whilst we have described herein a particular embodiment of the static line shock absorber 1, it is further envisaged that other embodiments of the invention could exhibit any number and combination of any one of the features previously described. However, it is to be understood that any variations and| modifications can be made 10 without changing the various components described herein, or departing from the spirit and scope thereof. The words "comprise", "comprising" and grammatical variations thereof, when used in this specification and in the following claims, are intended to specify the presence of 15 the recited features, but not preclude the addition of one or more other features, integers, components, steps or groups.

Claims (5)

1. A static line shock absorber for providing an effective means for slowing and breaking a person's fall in a fall arrest situation, the static line shock absorber 5 including: a shock absorbing plate adapted to be secured to a mounting plate by means of an anchor bracket, and attachable to an end of a static line cable, the shock absorbing plate comprising: a plurality of shock relief cuts to extend the shock absorbing plate to an 10 extended position in the fall arrest situation; and a plurality of shock relief holes located relative to the plurality of shock relief cuts to absorb and dissipate the energy generated by the person's fall.

2. A static line shock absorber as claimed in claim 1 wherein the shock absorbing 15 plate further comprises a body housing portion comprising an outer and inner cover plate for enclosing and protecting the shock absorbing plate against accidental extension.

3. A static line shock absorber as claimed in claim 2 wherein the shock absorbing 20 plate has provided two locating slots for aligning with and receiving two locating lugs of the body housing portion, and adapted as a locking feature for preventing extension of the shock absorbing plate below a pre-set working force limit, resulting from an accidental pull exerted by the person, thereby maintaining static line tension pre-set by means of an in-line tensioner. 25

4. A static line shock absorber as claimed in any one of the preceding claims wherein the shock absorbing plate is adaptable to be at least partly painted with a safety rated colour, to indicate its unsuitability for use after being extended in the fall arrest situation. 30

5. A static line shock absorber as substantially as hereinbefore described with reference to the above examples and drawing figures.