Static structures (e.g. – buildings) – Openwork; e.g. – truss – trellis – grille – screen – frame – or... – Superimposed three-dimensional units
Reexamination Certificate
2000-12-21
2002-06-25
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Openwork; e.g., truss, trellis, grille, screen, frame, or...
Superimposed three-dimensional units
C052S651010, C052S651100, C052S655100, C052S749100, C052S690000, C052S693000, C052S695000, C052S749100, C052S749100, C403S381000, C403S345000, C403S364000, C403S286000, C403S292000, C403S294000, C182S178100, C182S178200, C182S178300, C182S186700
Reexamination Certificate
active
06408587
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to structural members and to parts and fitting used and for use in association therewith.
Structural members to which the invention relates may be used for the construction of permanent or temporary structures for use in what may broadly be regarded as the entertainment industry. By way of example but not limitation, such structures may be used in association with a stage for the presentation of a musical/theatrical event, for the support of a roof over a stage, for carrying lighting, sound, scenery or other production equipment, or indeed anything that may be required. In many cases such structures are temporary if an event is taking place for a short period of time, but such a structure may well be permanently installed at a location. A further example of a situation in which structural members in accordance with the invention may be utilised is an exhibition stand, but in its broadest aspect structural members in accordance with the invention may be used wherever a requirement arises therefor.
A basic element from which such structures may be assembled is a “truss”, and more particularly a structural member in accordance with the invention may be such a truss. A truss characteristically comprises a number of elongate elements secured in spaced generally parallel relationship to one another by a number of transversely extending elements therebetween. The transversely extending elements are arranged to ensure that the truss is adequately strong and rigid for the loads it is intended to bear: typically some transversely extending elements extend perpendicularly to the elongate elements while other extend diagonally therebetween. Trusses particularly described hereafter are generally rectangular in transverse cross-sectional shape, with principal elongate elements at the corners of the rectangle, but generally trusses may be of other cross-sectional shapes, e.g. polygonal with more or less than four principal elongate elements. For special purposes, some trusses are able to be folded flat to occupy a minimal space for storage or transportation, and erected to an operative cross-sectional shape when required to be used. Generally, there are many known configurations of truss and the invention is applicable throughout the range of such configurations.
A structure may be created by joining a plurality of trusses together in the required configuration, using suitable connectors and fastenings as described hereafter. A structure may incorporate parts at a substantial height above a floor or ground level, and persons assembling the structure have to work at such heights. After the structure has been completed, further work will be necessary to mount other items such as lighting equipment thereon. Whilst theoretically separate access equipment should be used for safe working at a height, in practice the structure itself may be climbed upon and this brings obvious dangers in case of a fall. With this in view, a person may attach himself to a safety line which is clipped to a truss in the region in which work is taking place, but this inhibits freedom of movement and if a fall occurs may impose loads on the structure which could damage it. Add-on fall-arrest systems have been proposed, but these may interfere with the structure, imposing undue loads thereon, and generally are inconvenient.
SUMMARY OF THE INVENTION
It is broadly the object of one aspect of the present invention to address the above described problem of assisting safety of persons working at a height on a structure as above described.
According to one aspect of the invention, therefore, we provide a structural member comprising a number of elongate elements disposed in spaced generally parallel relationship to one another with transversely extending elements therebetween, wherein an element extending longitudinally of the structural member is provided with a formation extending lengthwise thereof for engagement by an attachment member to be retained to the longitudinally extending element at any of a range of positions therealong.
The attachment member may be adapted for connection to a safety element. Then it may be engaged with the formation of the elongate element in such a way as to be freely movable therealong.
Alternatively the attachment member may provide for the support of lighting or sound equipment for example to the structural member and may be intended, when engaged with the elongate element at a required position, to remain in such position.
The structural member may be generally of polygonal shape in cross-section, and some or all of the elongate elements may be disposed at the corners of such a polygonal shape. It may be at least one of said elongate elements which is provided with a respective said lengthwise-extending formation. Preferably all of said elongate elements constituting the structural member are of the same cross-sectional shape as one another, and thus each has a said formation.
The cross-sectional shape of the elements
10
-
13
, clearly seen in
FIG. 2
, comprises a hollow generally rectangular box-section portion
28
and a portion
29
which defines an undercut generally T-section track formation
30
(the T-section track formation
30
shown inverted in FIG.
2
). The portion
29
comprises side walls portions
31
,
32
which extend generally parallel to one another from adjacent edges of the portion
28
, the wall portions
31
,
32
ending at inwardly-facing lip portions
33
,
34
which extend towards one another to define an opening
115
therebetween. Oppositely outwardly extending recesses
116
are afforded beneath the lip portions
33
,
34
. The outwardly extending recesses
116
cooperate to form the cross-member of the “T” (which as states above is inverted in FIG.
2
). Lengthwise external ribbing on the elements
10
-
13
is visible in
FIGS. 2
,
4
, and
5
, but omitted from
FIG. 6
for clarity. Such external ribbing renders the element easier to grip and handle, to facilitate its use in erection of a structure.
Conveniently each of said elongate elements is an extrusion of an appropriate aluminium alloy. However, other materials may be suitable and it is contemplated that possibly a plastics material, e.g. fibre-reinforced, may be usable. Apart from a portion thereof having the lengthwise extending track formation, the or each elongate element may comprise a portion which is hollow, and which may be of generally square or rectangular transverse cross-sectional shape.
According to a further aspect of the invention, we provide a structure comprising at least one structural member in accordance with the first aspect of the invention as above set forth. The invention yet further provides such a structure having one or more attachment members engaged with one or more of said track formations thereof. Yet further, a safety device such as a safety lanyard may be connected to at least one of said attachment members.
Whether an attachment member is intended for connecting something to a track formation as above described at a fixed point along its length, or whether an attachment member for a safety element is movable along the track formation, engagement of such an attachment member with the track has in many cases hitherto required passing thereof lengthwise into the track from an end thereof. Similarly the attachment member has only been able to be disengaged from the track at an end thereof. Whilst this provides a high degree of safety in respect of the security with which the attachment member is held captive when it is in, for example, a mid-position along the track, it would in many cases be convenient if it were to be engageable with and disengageable from the track at such a mid-position. At the same time as providing this convenient ability, however, there should be a high degree of security against an intentional disengagement from the track.
It is broadly the object of another aspect of the present invention to provide an improved attachment member for such engagement with a track.
According
Cronin Christopher Patrick Noel
Darracott Neil Howard
Friedman Carl D.
Green Christy
Marshall Gerstein & Borun
Total Fabrications Limited
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