Leg attachment system and method for seats

A system to attach seats, in particular rows of lightweight seats to the light gauge deck of a high passenger marine craft. Horizontal flanges of aluminum angles (23) form a T-shaped foot locking within cavity (35) of track (29) fixed to the deck. High tensile tie straps (27a, 27b) are held between the vertical webs of the angles (23) by pins (69). A tubular pedestal (25) has upper recesses (49) which mate with a box beam supporting the seats. Threaded studs (73)of the tie straps (27a, 27b) are bolted to the box beam so that inertial forces arising in the event of an impact of the craft will be uniformly distributed by the pedestal, tie straps (27a, 27b), and angles (23), to the track for dissipation over an extended length of track, thus reducing the effects of localized shear. On assembly of the system, the angles (23) need not to be slid along the track but may be inserted individually being later spaced apart by insertion of tie straps (27a, 27b) so as to laterally the cavity (35).

TECHNICAL FIELD 
This invention relates to a leg attachment system and method for seats 
attached to a seat support. 
The invention has particular utility to the mounting of seats to the floor 
of a vehicle or the deck of a vessel where the seats of the vehicle or 
vessel can be subjected to an appreciable lateral force when the motion of 
the vehicle or vessel is suddenly impeded. 
The invention, however, is not limited to such application and has general 
utility as an attachment system for pedestals or standards of any general 
form which are required to be anchored to a floor and which may be subject 
to the application of a lateral force. 
BACKGROUND ART 
In recent times, and with the application of new technologies, large 
passenger carrying marine craft are achieving speeds of a magnitude 
normally experienced in motor vehicles and so are capable of subjecting 
passengers seated within them to high lateral forces which can cause 
serious injury if the motion of the vessel is suddenly impeded. 
One of the problems with designing leg attachment systems for seating in 
marine vessels, and which does not present itself to the same degree in 
relation to land based vehicles, is the weight consideration which 
seriously affects the design of the particular leg attachment system that 
is adopted. Moreover, in order to achieve high speeds, passenger ferry 
craft are required to be light weight, whereby the weight of the vessel 
directly affects the maximum speed that can be obtained by the vessel. 
Consequently, passenger ferry craft these days are constructed with decks 
of extremely light gauge material, for example aluminium sheeting which 
can reach thicknesses of down to 2 mm. Consequently, the leg attachment 
systems that have previously been designed for seating to attach to decks 
of such light gauge material have similarly been of light weight design 
and hence have skimped on meeting minimum safety standards for resisting 
laterally applied impact forces. 
An immediate solution to the problem would be to make leg attachment 
systems of heavier gauge material, however the inherent problem with this 
is that this would considerably add to the weight of the vessel. 
A further problem is that the beam of marine craft is not limited to the 
same extent as the breadth of land based vehicles and hence there is much 
more flexibility in the positioning and the number of seats that are able 
to be mounted upon a deck than is the case with land based motor vehicles. 
Hence, the ability to position seats easily and removably is also an 
important design consideration which detracts from having permanent fixed 
point anchoring systems for leg attachment systems, which are easier to 
design for meeting high loading requirements than is the case of 
impermanent anchoring points and fixtures. 
Present types of anchoring techniques for leg attachment systems are 
basically divided into three classes. The first is the flange or base 
plate anchoring system as shown in FIG. 1A of the accompanying drawings, 
the second is the block mounted anchoring system as shown in FIG. 1B of 
the drawings, and the third is the track mounted anchoring system using 
either diamond or T-head bolts (not shown) or angle bolts shown in FIG. 
1C. 
As shown in FIG. 1C, this system uses an interlocking angle `a` to which 
tie bolts `b` are fixedly mounted to fixedly retain a seat pedestal leg 
`c` to a track `d`. The track `d` itself is permanently fixed to the deck 
and is formed with a longitudinally extending cavity, centrally disposed 
within and circumscribed by a C-shaped channel portion `e`. Such an 
arrangement has the advantage that the interlocking angle can be 
positioned close to the installation site without having to be slid along 
the entire length of deck track, which would otherwise be the case if a 
captive T-head section was used. Although a T-head section would provide 
greater locking ability and hence strength, as lengths of track can be as 
long as 50 m or more along a deck, such a system is impractical to use. 
The first two of these systems falls into the category of permanent 
affixture anchoring points and is not attractive to the industry due to 
the inability to change the fixing position of the leg attachment for the 
seats, once it is fixed in position. A further problem is that almost all 
of the impact force is directly transferred to the deck of the vessel at 
the fixing point of the bolts, in the case of the flange or base plate 
arrangement, and the blocks, in the block mounted arrangement. Such forces 
consequently impose considerable shear upon the deck itself and in the 
case of lightweight thin gauge deck construction, the anchoring systems 
are able to pull out directly from the deck at relatively low impact 
forces, causing permanent damage to the deck itself. 
The track arrangement, however, is generally accepted as the industry 
standard, whereby the track system allows for easy and impermanent 
positioning of the anchoring means therealong, whilst causing the impact 
forces to be applied to the track itself rather than the deck. 
Accordingly, the track system allows the leg attachments for seats to be 
easily slid into position, and the track itself can be attached to the 
deck using various fixing systems, including rivet and nut inserts which 
allow forces transmitted to the track to be more uniformly spread along 
the deck, reducing shear. In addition, the track provides a continuous 
attachment method for the leg attachments of the seats to the deck, where 
the leg attachments can be adjustably positioned at any time by sliding 
the legs in the track to the correct position. 
Notwithstanding this improved arrangement, the two types of anchoring 
systems used with the track arrangement, namely the diamond or T-head bolt 
anchoring system or the angle bolt anchoring system, have been found to be 
limited with respect to the size of the impact force that can be 
accommodated and fall short of the standards recently set by the 
International Maritime Organisation which are applicable to high speed 
passenger carrying vessels. 
Moreover, in the case of the diamond or T-head bolt arrangements, impact 
forces are still transmitted by the anchoring system to the track at point 
locations, consequently causing shearing of the anchoring means from the 
track at these points. In the case of the angle bolt attachment system, 
although impact forces are applied more uniformly along the angle, due to 
the limited ability of the angle to lock into the cavity of the C-shaped 
channel design of the track, the angle itself has a tendency to pull out 
or shear from the track by the impact force, creating a bending moment 
around the flange or lip `f` of the track which engages the flange of the 
angle. 
Safety standards imposed by the International Maritime Organisation are 
calculated in accordance with a vessel's "G" rating. Moreover, each type 
of vessel has a "G" rating associated therewith which equates to the 
likely inertial forces that may be applied to passengers, having regard to 
the vessel size, its speed and weight. 
"G" ratings for most large passenger carrying marine craft require leg 
attachment systems to resist impact forces in the region of 600 kg. With 
respect to the previously described prior art leg attachment systems, 
impact force resistance of only 300 kg to 400 kg can be achieved before 
experiencing vertical separation of the leg attachment from the deck or 
the track. 
DISCLOSURE OF INVENTION 
Accordingly, it is an object of the present invention to provide an 
improved leg attachment system which overcomes some or all of the 
disadvantages associated with prior art leg attachment systems as 
described above, and which in particular provides for opposing and 
dissipating impact forces of a magnitude to meet recent standards adopted 
by the International Maritime Organisation. 
In accordance with one aspect of the present invention, there is provided a 
leg attachment for seats mounted to a seat support, including: 
an anchoring means for lockingly engaging a base having a track therein, 
said base being fixedly mounted to a support; 
leg means for surmounting said anchoring means and supporting a seat 
support thereon; and 
tie means for released fixed attachment to said anchoring means at one end 
and clamped locking engagement to the seat support at the other end, such 
that increased locking engagement of said tie means with the seat support 
positively locks said leg means to said anchoring means; 
wherein lateral forces applied to the seat support are transferred by said 
leg means and said tie means to said anchoring means, whilst 
simultaneously being disseminated through said leg means; 
and wherein said anchoring means is adapted to dissipate the force 
transferred thereto uniformly over an expansive portion of the track base 
Preferably, said anchoring means comprises a pair of interlocking angles, 
each having an outer flanged end, for being positively engaged within a 
longitudinally extending cavity centrally disposed within and 
circumscribed by a C-shaped channel portion of the track, and a 
substantially planar web portion for projecting outwardly from the cavity; 
wherein said flanged ends combinedly define a T-shaped foot for locking 
engagement within the cavity and said web portions define a leg for 
attachment to said tie means, when said interlocking angles are brought 
into juxtaposition with each other. 
Preferably, the combined transverse extent of said flanged ends is 
marginally less than the corresponding maximal transverse extent of the 
cavity, and the combined transverse extent of the web portions proximate 
to said foot is marginally less than the minimal transverse extent of the 
cavity, so that said interlocking angles are required to be transversely 
spaced apart a prescribed distance to fully occupy and engage said cavity 
when in said juxtaposition, to enable one interlocking angle to be 
discretely withdrawn from engagement with the track by lateral rotation 
thereof relative to the other interlocking angle. 
Preferably, said web portions are each provided with a corresponding 
transversely extending aperture to facilitate attachment to said tie 
means. 
Preferably, said leg means comprises a tubular pedestal having a base end 
for sitting upon the track whilst surmounting said anchoring means, and an 
opposing support end formed with a transversely extending recess of 
complementary shape to the seat support to accommodate a longitudinal 
portion of the seat support, transversely across said pedestal. 
Preferably, said tie means comprises a shank portion for extending along 
and within said tubular pedestal, said one end having a transversely 
extending aperture for aligning with corresponding apertures of said 
anchoring means to facilitate attachment thereto. 
Preferably, said other end of said tie means is formed with a screw 
threaded fastening means for locating within a corresponding aperture 
disposed upon the support beam and for clampingly and lockingly engaging 
the seat support positively upon said tubular pedestal within said recess 
on increased locking engagement of said fastening means upon the seat 
support. 
Preferably, said one end is able to be releasedly pinned to said anchoring 
means by means of a pin inserted through the corresponding apertures of 
said web portions and said one end when brought into relative axial 
alignment. 
Preferably, said shank portion comprises a strap of commensurate transverse 
extent at said one end to said prescribed distance for being disposed 
interposedly between said web portions, so as to maintain locking 
engagement of said foot with the track. 
In accordance with another aspect of the present invention, there is 
provided a leg attachment system for seats mounted to a seat support, 
comprising: 
a base having a track for fixed mounting to a support; and 
a leg attachment including: 
(i) an anchoring means for lockingly engaging said track; 
(ii) leg means for surmounting said anchoring means and supporting a seat 
support thereon; and 
(iii) tie means for released fixed attachment to said anchoring means at 
one end and clamped engagement to the seat support at the other end, such 
that increased locking engagement of said tie means with the seat support 
positively locks said leg means to said anchoring means; 
wherein lateral forces applied to the seat support are transferred by said 
leg means and said tie means to said anchoring means, whilst 
simultaneously being disseminated through said leg means; 
and wherein said anchoring means is adapted to dissipate the force 
transferred thereto uniformly over an expansive portion of said base. 
In accordance with another aspect of the present invention, there is 
provided a method of forming a demountable leg attachment system for 
seats, comprising: 
fixedly mounting a base having a track therein to a support; 
inserting anchoring means into said track to lockingly engage therewith; 
releasedly attaching tie means to said anchoring means, so that said tie 
means can project upwardly therefrom; 
surmounting a leg means for supporting a seat support, over said anchoring 
means so that said tie means is disposed within the confines of the leg 
means and can extend therealong; 
positioning a seat support upon the top of said leg means and locating the 
ends of said tie means to extend through said seat support; 
clampingly engaging said seat support to said leg means by locking 
engagement of said tie means with said seat support, and consequently 
clampingly engaging said leg means upon said track; 
wherein lateral forces applied to said seat support are transferred by said 
leg means and said tie means to said anchoring means, whilst 
simultaneously being disseminated through said leg means; 
and wherein forces transferred to said anchoring means are dissipated 
uniformly over an expansive portion of said base. 
In this manner, leg attachments and hence seats can be positioned at any 
location along long lengths of deck track without having to slide captive 
T sections from one end, whilst maintaining maximum resistance to vertical 
separation of the anchoring system from the track.

SPECIFIC EMBODIMENTS OF THE INVENTION 
In the description of the embodiments and drawings associated therewith, 
the same reference numerals have been used to identify common features of 
the embodiments. 
As shown in FIG. 1 of the drawings, all of the embodiments are directed 
towards a demountable leg attachment system for attaching rows of 
lightweight seats 11 to the deck 13 of a high speed passenger marine 
craft, via a seat support beam 15 which has the seats fixedly attached 
thereto. The beam 15 is supported by two or more pedestal legs 17 which 
are in turn lockingly engaged with respective bases 19 comprising tracks 
which run longitudinally and are fixedly attached to the deck 13 of the 
vessel. 
The first embodiment is directed towards a demountable leg attachment 
system 21 comprising an anchoring means in the form of a pair of 
interlocking angles 23, leg means in the form of a tubular pedestal 25, 
tie means in the form of a 15 pair of tie straps 27, a base comprising a 
track 29 and a seat support beam 31. 
The track 29 is of the conventional extruded aluminium form having a 
C-shaped channel portion 33 centrally disposed therein and defining and 
circumscribing a longitudinally extending cavity 35 therein. The track 29 
is also provided with a pair of outwardly projecting longitudinally 
extending flanges 37, each having a proximal planar portion 37a and a 
downturned distal portion 37b. The proximal portions 37a respectively 
define inwardly projecting flanges or lips 39 which are spaced apart a 
prescribed distance in opposing relationship to define an opening into the 
cavity 35 of the track. The distal portions 37b have a downward extent 
commensurate to the height of the C-shaped channel to engage the deck 
lining in conjunction with the bottom of the C-shaped channel 33 which 
engages the deck itself. Accordingly, the distal portions 37b provide a 
clean finish for carpet or other deck covering which terminates adjacent 
to the channel 33. 
The track 29 is fixedly attached to the deck by screws, rivets, welding or 
other fastening arrangement. 
The seat support beam 31 is also of conventional extruded aluminium form, 
comprising a trapezial box channel portion 41 and a planar flanged 
mounting portion 43, contiguous with the long and parallel side of the 
channel portion. 
The opposing sides of the mounting portion 43 comprise longitudinally 
extending flanged ends 43a to facilitate attachment to the leg attachment 
system in a manner to be described later. 
The mounting portion 43 provides a surface to which the seats 11 are 
fixedly mounted by a nut and bolt fastening arrangement or the like and 
the boxed channel portion 41 is disposed to depend from the mounting 
portion 43 to surmount the pedestal 25. Accordingly, the support beam 31 
is disposed transversely of a series of seats 11 disposed side by side as 
shown in FIG. 1 of the drawings for attachment thereto. 
The tubular pedestal 25 is of substantially rectangular extruded aluminium 
form having a pair of opposing side panels 45 which are interconnected by 
a pair of opposing end panels 47. The opposing axial ends of the pedestal 
are terminated in planes which are obliquely disposed relative to the 
axial extent of the pedestal so that the top of the pedestal projects 
forwardly when seated upon its base end and the top end is inclined 
downwardly towards the rear of the pedestal. 
The side panels 45 have corresponding recesses 49 formed therein of 
complementary shape to the trapezial box channel portion 41 in section so 
that the support beam 31 can be accommodated therein in a transverse 
relationship with respect to the pedestal. The recesses 49 are centrally 
disposed between he end panels 47 and terminate marginally therefrom to 
define a pair of opposing end landings 51a and 51b which provide a seat 
for the opposing flanged ends 43a and 43b of the seat mounting portion 43. 
The corners of the panels 45 and 47 are truncated so that the longitudinal 
sides 48 of both end panels function to facilitate locating the pedestal 
25 laterally relative to the tie straps 27 to enable the pedestal to be 
locked centrally upon the track 29 in a manner that should become apparent 
later. This facility is of more importance to the second embodiment and 
will be described in more detail in relation to that embodiment. 
The posterior end panel 47a has a rectangular aperture 50 formed therein 
which is disposed a prescribed distance from the bottom end of the 
pedestal to enable interlocking engagement with the interlocking angles in 
a manner to be described later. The anterior end panel 47b is formed with 
a rectangular recess 52 at the bottom end of the pedestal which extends 
along the end panel a prescribed distance from the bottom edge to 
terminate at a prescribed height above the bottom end of the pedestal 
corresponding to the tope of said interlocking angles thereat. 
Accordingly, the recess 52 is sized to accommodate the interlocking angles 
23 in a position so that the pedestal 25 can surmount both the angles 
simultaneously with the bottom end of the pedestal sifting symmetrically 
upon the proximal planar portion 37a of the track. 
The interlocking angles 23 are formed of aluminium plate and each are 
provided with a longitudinally extending flanged end portion 53 and an 
elongated web portion 55. The length and height of the angles 23 is 
determined in accordance with impact force resistance calculations, and in 
the present embodiment, the length is longer than the distance between the 
end panels 47 of the pedestal 25. The posterior end 57 of the interlocking 
angles 23 is obliquely angled relative to the longitudinal extent of the 
flanged end portions 53 and is parallel with the panel ends 47 of the 
pedestal 25, when the pedestal is correctly disposed upon the track 29. 
As shown in FIG. 3 of the drawings, the posterior end 57 is stepped to 
define an outwardly projecting tongue 59 which is correspondingly sized to 
repose within the posterior aperture 50 of the pedestal. The anterior ends 
61 of the interlocking angles 23 are each tapered from the posterior end 
57 a distance marginally greater than the distance between the end panels 
47 of the pedestal. The tapering is provided to reduce on the amount of 
material involved with forming the interlocking angles 23, without unduly 
sacrificing on strength, and furthermore mitigates the obtrusive nature of 
the interlocking angles 23 extending anteriorly of the leg attachment 
system, and avoids the presence of any sharp edges on which people may 
catch themselves moving to or from the seats. 
The web portions 55 are provided with a plurality of apertures which extend 
transversely therethrough and which are correspondingly aligned when the 
angles are disposed in juxtaposed corresponding relationship with each 
other. Two of the apertures 65 are disposed towards the posterior end 57 
of the interlocking angles 23 and one aperture 67 is disposed intermediate 
of the web portion 55 a prescribed distance from the aperture 65 which is 
less than the spacing between the end panels 47. 
Importantly, the flanged ends 53 of the interlocking angles 23 define a 
T-shaped foot for locking engagement within the cavity 35 when the flange 
plates are brought into juxtaposition with each other. Further, the 
combined transverse extent of the flanged ends 53 is marginally less than 
the corresponding maximal transverse extent of the cavity 35. In addition, 
the combined transverse extent of the web portions 55, proximate to the 
foot, is marginally less than the minimal transverse extent of the cavity 
which corresponds to the opening disposed between the lips 39 of the track 
29. The significance of this will be described in further detail later. 
The tie straps 27 are formed of an appropriate high tensile steel and 
comprise a shank portion 71 and a threaded bolt stem 73 connected thereto. 
The bottom end of the shank portion is obliquely angled relative to the 
longitudinal axis of the strap for engaging the bottom of the C-shaped 
channel portion 33 of the track 29. The bolt stem 73 is welded to the 
other end of the shank portion and forms part of a screw threaded 
fastening means for affixing to the support beam 31. The other part of the 
fastening means comprises bolt fasteners 75 and washers 77 which are 
corresponding sized to screw upon the threaded bolt stems 73. 
The length of the shank portion 71 is marginally less than the length of 
the pedestal 45 and the bolt stems 73 project longitudinally from the 
outer ends of the shank portion 71 at an attitude which is orthogonal to 
the plane of the top end of the pedestal, defined by the landings 51a and 
51b when correctly positioned within the pedestal. 
The bottom ends of the shank portions 71 are provided with apertures (not 
shown) to align with the apertures 65 and 67 of the interlocking angles 23 
respectively. Moreover, the posterior tie strap 27a is intended to be 
disposed towards the rear of the pedestal 25 and is provided with two 
apertures which are disposed along the shank portion 71 at corresponding 
distances from the bottom end of the shank portion as are the rear 
apertures 65 relative to the bottom of the interlocking angles 23. In this 
manner, the apertures 65 and the corresponding apertures of the posterior 
tie strap 27a can be aligned in position when the tie strap 27a is 
disposed within the cavity 35, together with the interlocking angles 23. 
The anterior tie strap 27b is intended to be disposed towards the front of 
the pedestal 25 and is provided with an aperture disposed along the shank 
portion 71 thereof at a corresponding distance from the bottom end of the 
shank portion as are the apertures 67 relative to the bottom of the 
interlocking angles 23 thereof. Consequently, the corresponding aperture 
67 and the aperture of the tie strap 27b can be aligned when the tie strap 
27b is disposed in the cavity 35 in conjunction with the interlocking 
angles 23. 
Accordingly, the apertures 65 and 67 of the interlocking angles are 
correspondingly sized with respect to the apertures of the tie straps 27 
so that when aligned, respective pins 69 are able to be inserted through 
the web portions and the straps transversely to releasedly pin the straps 
to the angles. 
The relative positioning of the apertures 65 and 67 along the interlocking 
angles 23 is precisely determined so that the rear longitudinal edge 71a 
of the posterior tie strap 27a is disposed in corresponding angular 
relationship relative to the track 29 as is the posterior end panel 47 of 
the pedestal when the pedestal 25 is mounted on the track itself. That is, 
the rear longitudinal edge 71a of the tie strap is disposed in parallel 
relationship to the end panel 47. 
Further, the relative longitudinal spacing of the apertures 65 and 67 along 
the web portions 55 is such that when the tie straps 27 are pinned to 
their corresponding apertures, and the anterior tie strap 27b is disposed 
in parallel relationship to the posterior tie strap 27a, the distance 
between the rear longitudinal edge 71a of the posterior tie strap 27a and 
the anterior longitudinal edge 71b of the anterior tie strap 27b is 
commensurate to the spacing between the end panels 47 of the pedestal. 
Further, the combined transverse extent of the web portions 55, as spaced 
apart by the tie straps 27, is commensurate to the transverse extent of 
the end panels 47 between the longitudinal sides 48 thereof, and the 
longitudinal extent and spacial positioning of the pins 69 is similarly 
commensurate to the corresponding transverse extent of the adjacent 
portions of the truncated corners of the pedestal 25. In this manner, the 
pedestal 25 can be fitted upon the assembled tie straps and interlocking 
angles to surmount the angles and automatically align the tie straps 27 in 
parallel and juxtaposed relationship with the end panels 47 of the 
pedestal, as well as symmetrically locate upon the track 29 and lock in 
the pins and interlocking angles in position. 
The bolt stems 73 consequently are disposed apart in parallel relationship 
a prescribed distance, when the tie straps are assembled into position. 
This enables correspondingly spaced bolt holes 79 to be disposed within 
the opposing flanged ends 43a of the support beam 31 and the bolt stems 73 
to be inserted therethrough when the support beam 31 is correctly 
positioned upon the pedestal 25. 
Consequently, the support beam 31 can be positively locked into position on 
the pedestal 25 by screwing the nut fasteners 75 together with washers 77 
onto the threaded bolt stems 73. 
Now describing the method of assembling the leg attachment system, the 
interlocking angles 23 are inserted into the track one at a time, as shown 
in FIGS. 5b and 5c by disposing the flanged end 53 of an angle in parallel 
alignment with the cavity 35, and hooking the flanged end 53 under the 
corresponding lip 39 of the track, rotating the plate around the lip as is 
necessary. Accordingly, the thickness of the web portions 55 and the 
dimensioning of the C-shaped channel portion needs to be such as to allow 
sufficient clearance between the angles to allow this discrete hooking 
engagement with the corresponding lip, whilst the other angle is disposed 
in its locking position, as shown in FIG. 5c of the drawings. 
After both plates 23 are engaged within the track, they are transversely 
spaced apart a distance commensurate to the thickness of the bottom ends 
of the shank portions 71 of the tie straps 27. Accordingly, the flanged 
ends 53 may be provided with a stepped edge 54 to fully occupy and engage 
the cavity when in juxtaposed spaced apart relationship to each other, to 
accommodate the shank portion of the strap, as shown in FIG. 5d of the 
drawings. 
The tie straps are disposed so that the bottom end of the shank portions 71 
engage the bottom of the channel portion 33 and the corresponding 
apertures 65 and 67 of the flange plates are aligned with the 
corresponding apertures of the straps so that the pins 69 can be inserted 
therethrough to fixedly attach the straps to the plates. 
At this position, the posterior tie strap 27a generally adopts its final 
position, however the anterior tie strap 27b may be able to pivot to some 
degree about its single pin. 
The pedestal 25 is then positioned so that the top of the tie straps are 
inserted through the tubular confines of the pedestal 25 from the bottom 
end thereof, whereby due to the precise positioning of the pins and 
apertures, the anterior tie strap will pivot around its pin 69 so that the 
anterior longitudinal edge 71b thereof moves into parallel engagement with 
the anterior end panel 47b as the bottom end of the pedestal is 
progressively moved towards and ultimately engages the track 29. 
Importantly, the tongues 59 of the interlocking angles 23 simultaneously 
engage the rectangular aperture 50 of the posterior end panel 47a, and the 
leading end of the interlocking angles extend through the recess 52 of the 
anterior end panel 47b as shown in FIGS. 2 and 3 of the drawings. 
Importantly, the geometry of the pin and aperture positions together with 
the positioning and sizing of the bolt straps and pedestal, automatically 
causes the engagement between the tongue and the aperture and the parallel 
arrangement of the tie straps so as to minimise the likelihood of human 
error in the assembly operation. 
At this position, the support beam 31 is then disposed so that the bolt 
holes 79 are aligned with the bolt stems 73 and the trapezial box channel 
portion 41 is positioned to sit within the complementary recesses 49 of 
the pedestal. The nut fasteners 75 and washers 77 can then be inserted and 
screwed upon the bolt stems 73, clamping the support beam 31, 15 and 
pedestal 25 into position. 
It is important to note that the foot of the interlocking angles 23 fully 
occupies the cavity 35 of the channel portion 33 of the track to maximise 
locking engagement with the inner lips 39 of the track, which allows not 
only increased locking engagement of the support beam and pedestal with 
the track but also maximises the ability of the leg attachment to resist 
the application of lateral forces thereto. 
The demounting of the leg attachment system is achieved by simply 
performing the reverse process to the assembly operation. 
The operation of the leg attachment system in resisting inertial forces 
generated by seat components and occupants acting upon such components 
when the forward momentum of the vessel is suddenly impeded, as would 
occur in a collision, will now be considered. In such a circumstance, the 
normal tendency of the leg attachment is to move forwardly about its 
anchoring points. In the present embodiment, such tendency to move 
forwardly is opposed by the pin arrangement of the posterior strap, the 
engagement between the posterior end panel 47a and the posterior tie strap 
27a, the engagement between the anterior end panel 47b and the anterior 
tie strap 27b, and the engagement of the tongue with the bottom edge of 
the aperture 50. Thus, the anchoring means, pedestal and tie means are all 
held together and are able to resist vertical movement during application 
of a lateral force directed at the level of the seat by dissipating the 
force uniformly through each of these components and not just 
concentrating the force upon the tie means, as is the case with prior art 
systems. 
Accordingly, there is a reduced tendency to allow small movements of the 
tie straps which would otherwise tend to change the geometric arrangement 
of the components, causing an increased load to be placed upon the tie 
straps for the same external load, increasing shear forces. 
In addition, the length and height of the flange plates is increased 
compared with prior art systems so that the leading ends of the 
interlocking angles protrude forwardly through the recess 52 to provide an 
increased engagement length of the anchoring means with the track, whilst 
maintaining feet clearance for seat occupants of the seats behind. This 
configuration provides an increased capacity of the leg attachment to 
resist dislodgement forces during a vessel impact without significantly 
increasing the weight of the attachment. 
By virtue of the leg attachment system of the present embodiment, extremely 
high impact resistance loadings can be achieved, in excess of 2,100 kg. 
Accordingly, the present embodiment represents a vast improvement over 
prior art leg attachment systems. 
The second embodiment is substantially similar to the first embodiment 
except that it is directed towards a demountable leg attachment system as 
shown in FIGS. 6 and 7, which has an anchoring means confined to the 
inside of the pedestal for aesthetic, purposes and for applications where 
impact force resistance requirements are not as great to conform with 
safety requirements. 
As shown in the drawings, the track, support beam, pedestal and tie strap 
components of the system are substantially identical to those of the 
previous embodiment. The anchoring means, however, comprises a pair of 
shortened interlocking angles 81 of commensurate length to the spacing 
between the end panels 47 of the pedestal 25. Accordingly, the 
interlocking angles omit the provision of a tongue and a leading 
protruding end thereof, and the pedestal omits the posterior aperture 50 
and the anterior recess 52 thereof. Apart from this, the anchoring means 
is identical to that of the preceding embodiment. 
With the omission of the aforementioned components from the interlocking 
angles and the pedestal, the configuration of the end panels 47 and the 
truncated corners thereof become pre-eminent in locating the pedestal 
centrally upon the interlocking angles, the straps and track, and locking 
in the pins, web portions and straps during assembly. In this respect, the 
opposing ends of the web portions sit in abutting engagement with the 
adjacent planar portions of the end panels so that the longitudinal sides 
48 are each disposed adjacent to the outer transverse extent of the spaced 
web portions at each end thereof, thereby centrally and symmetrically 
locating the pedestal upon the track. 
Although this type of leg attachment system cannot achieve the same impact 
resistance loads as is the case of the previous embodiment, it still is a 
vast improvement upon prior art systems, whereby loadings in the order of 
1,500 kg are still able to be achieved by this embodiment. 
The third embodiment is directed towards a leg attachment system having an 
alternative form of anchoring means and tie means, as shown in FIGS. 9 to 
15 of the drawings. 
In this embodiment, the anchoring means comprises a pair of interlocking 
angles 91 which are of a greater thickness than is the case of the 
interlocking angles of the preceding embodiments, so as to fully occupy 
the cavity of the track when disposed in juxtaposed relationship with 
respect to each other as shown in FIG. 10 of the drawings. 
In order to achieve this juxtaposed positioning of the interlocking angles, 
the angles have to be inserted serially of each other along the track and 
then be slid along the track together to adopt the juxtaposed 
corresponding position as shown in FIG. 9 of the drawings. 
Furthermore, both of the interlocking angles 91 have a longitudinal extent 
greater than the spacing between the end panels 47 of the pedestal, as in 
the case of the first embodiment, however instead of being formed with a 
tapered leading end, the angles are formed with a rearwardly protruding 
tapered tail portion 93. 
Consequently, the pedestal is formed with a posterior recess 95 within the 
posterior end panel 47a along the bottom edge thereof to accommodate the 
rearward extension of the interlocking angles through the pedestal. 
The leading ends 97 of the interlocking angles are obliquely disposed 
relative to the bottom longitudinal edge thereof to adopt a parallel 
relationship, when fitted into position, with the anterior end panel 47b 
of the pedestal. Accordingly, the inner face of the anterior end panel 47b 
is able to be brought into butting relationship with the leading ends 97 
of the interlocking angles, as shown in FIG. 9 of the drawings, when 
assembled. 
The web portions 94 of each of the interlocking angles 91 are each provided 
with a single corresponding aperture 98 disposed at an intermediate 
position between the anterior end 97 and the tail portion 93 so as to be 
disposed within the confines of the pedestal when assembled. Accordingly, 
when the interlocking angles 91 are juxtaposed in corresponding 
relationship, the apertures 98 of each of the angles are disposed in axial 
alignment. 
The tie means comprises anterior and posterior ties. 
The posterior tie comprises a shank portion 99, a U-shaped bracket 101 
fixedly mounted to the bottom of the shank portion 99, and a threaded end 
103 which forms part of a threaded fastener, the other part comprising a 
fastener nut 105 and washer 107 as shown in FIG. 12 of the drawings. The 
U-shaped bracket 101 has a pair of transversely extending apertures 109 
disposed therein of corresponding size to the apertures 98 of the 
interlocking angles. Accordingly, the U-shaped bracket 101 is adapted to 
surmount the top of the flange plates when disposed in their corresponding 
juxtaposed position so that the aperture 109 thereof can be disposed in 
axial alignment with respect to the apertures 98 of the interlocking 
angles. 
Consequently, a removable pin 111 is provided to be inserted axially 
through the aligned apertures to pivotally and fixedly attach the 
posterior tie means to the anchoring means. 
The anterior tie means comprises a mounting bolt 113, which has a curved 
threaded bolt stem 115 connected to the top of the anterior end panel 47b, 
to project outwardly from the top of the pedestal 25, orthogonally of the 
plane of the top of the pedestal. 
Similarly, the top of the shank portion 99 is curved so that the threaded 
end 103 adopts an axial position which is disposed parallel to the 
threaded stem 115 of the mounting bolt 113. The mounting bolt 113 and the 
threaded end 103 are arranged so that when disposed in a parallel axial 
position, they align with the corresponding bolt holes 79 of the support 
beam 31 so that the support beam can be mounted thereon and accommodated 
within the recess 49 of the pedestal in a similar manner to the previous 
embodiments, as shown in FIG. 7 of the drawings. 
Assembly of the leg attachment system of the present embodiment is achieved 
by positioning the interlocking angles 91 into the track and sliding them 
into the juxtaposed corresponding position as previously described. The 
posterior tie means is then positioned upon the interlocking angles and 
the pin 111 inserted through the aligned apertures. 
The pedestal 25 is then positioned over the posterior tie means to surmount 
the anchoring means and to sit upon the track. 
The anterior tie means comprising the mounting bolt is then inserted into 
position and the support beam is located upon the threaded ends of the 
respective anterior and posterior ties. The fastening nuts and washers are 
then screwed onto the respective threaded ends of the ties, and the 
support beam, pedestal and anchoring means are all locked into position. 
The above arrangement, although providing impact resistance loads in excess 
of the prior art and meeting minimum standards of the International 
Maritime Organisation, is somewhat inferior to the leg attachment systems 
described in the preceding embodiments. 
The principal reason for this is that the posterior tie means takes most of 
the impact load upon application of a lateral force, and hence is not as 
efficient in distributing the load to the foot of the anchoring means and 
to the pedestal as is the case in the preceding embodiments. Consequently, 
the impact load resistance of this form of leg attachment system is 
principally limited by the strength of the shank portion to resisting 
shear forces applied principally at the fastener end. 
Notwithstanding the above, it should be appreciated that the present 
embodiment still represents a significant advance over prior art leg 
attachment systems and can have utility where this type of leg attachment 
system is preferred to that of the preceding embodiments. 
It should be appreciated that the scope of the present invention is not 
limited to the particular embodiments herein described and that changes 
and modifications to the embodiments can be made without departing from 
the spirit or scope of the invention. 
Moreover, where it is desirable to achieve an increased dampening effect on 
the resistance of the leg attachment system to impact or inertial forces 
applied to the seat, modifications can be made to the tie means and 
anchoring means to provide the same. One way of achieving this is to 
replace the posterior tie strap of the first and second embodiments with a 
structural member which extends inelastically under tensile loads beyond 
the normal load range during service. Such a device may be a preformed 
metal strap having a concertinaed shank portion as illustrated in FIGS. 
16a and 16b of the drawings, or an alternative metal strap having a 
perforated shank portion as illustrated in FIG. 17 of the drawings. 
Attachment of either of these extensible straps can be conveniently 
accommodated between the two interlocking angles using a simple 
arrangement of pins as described in the preceding embodiments. 
In a further modification to the embodiments, an inextensible strap could 
be fastened by deformable pins as illustrated in FIGS. 18a and 18b of the 
drawings, or deformable slots as illustrated in FIG. 19, or deformable 
interlocking angles to allow controlled movement of the seat leg assembly 
at defined loads, but without separation of the components. 
A further modification would be a combination using either of the two 
aforementioned modifications.