Note: Descriptions are shown in the official language in which they were submitted.
1~8~.b~4S
. . SUPPORT STRUCTURE FOR FOLDING TABLES
,
AND LIKE STRUCTUR~S
This invention relates to a folding table or
: ~ similar collapsible structures having a generally flat
5 top, rectangular in outline and four collapsible legs
which can be readily folded against the underside of the
. table~.
. .
According to the invention there is provided a
~olding table or like structure having a generally planar
10 tahle top .supported on the floor by multiple legs and a
; cable network, wherein the legs are articulated below the
~ ~able top at spaced points located inwardly from the
: ~ e~e o~ the ~able, said legs comprising two splayed legs
i~ V~formation extending each from each point of
- 15 articulation to points on the floor and said cable
. netwo~k interconnecting the lower ends of said legs and
extending from proximate each corner of the table top to
the lower end of a leg located therebelow, the
arrangement being such that in the assembled state al'l
: ~ ~0 cables are in tension and the legs are in compression.
According to a further aspect of the inven~ion
:: there i5 provided a folding table or like structure
i~cluding a generally planar solid table top, two pairs
~ of supporting legs depending from the underside of sàid
: 25 table t~p, each pair of leg~ defining an inverted V with
the apices of said pairs articulated to said underside
of the table top at locations spaced apart to provide a
table which is symmetrlcal in the erected state, a cable
,
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network interconnecting the ends of the legs remote from
the articulated apices and connecting said leg ends with
said underside of the table top, and separate tensioning
means each secured on the underside of the table top and
5 associated one with each articulated apex to place the
cable network in tension and the diverging legs in
compression when the table is in the erected state.
According toa fur~er aspect of the invention
there is provided a folding table comprising: a generally
10 planar loosely supported rigid table top, two points of
articulation located below the underside of ~he table
top approximately midway between the plane of the table
top and the floor, an upper and a lower pair of splayed
legs in V-forma~ion extending from each point of
15 articulation, the ends of the lower legs resting on the
floor and the ends of the upper legs supporting the
table top, a transverse bar extending between the points
of articulation and substantially parallel to the table
top, lower cables interconnecting the lower ends of
20 said legs, upright cables extending generally from the
upper ends of the upper legs to the lower leg ends of
the lower legs, and upper cables interconnecting the
upper ends of said legs, and force release means for
placing the cables under tension; the arrangement being
25 such that in the assembled state all the cables are in
tension and the legs are in compression.
According to a further aspect of the invention
there is provided a folding structure or use as camping
table or bed comprising: a generally rectangular top
30 made from flexible material, two points of articulation
located below ~he underside of the top and which, when
the folding structure is erected, are disposed
approximately midway between the plane of the top and
, the ground, an upper and a lower pair of splay~d legs in
35 V-formation extending from each point of articulation,
the e~ds of the lower legs resting on the ground and the
ends of the upper legs engaging the ~op, a transverse
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bar extending between the peints of articulation and
sub~tantially parallel to the top, lower cables
intarconnecting the lower ends of said leg~ and upright
cable~ extending from the upper end~ of the upper leg3
5 to the lower ends of the lower legs, and upper cables
interconnecting the upper ends of said legs, and force
relea e means for placing the cables under tension, the
arrangement being such that in the assembled state all
the cables are in ~ension and the top is stretched
10 between the upper ends of the upper pair of legs.
In the tensioned aondition of ona embodiment
o tha invenkion~ the lower ~ys~em of cables form~ a
planar support so that the table ~tructure can be put
on 30~t ground or sand without lo~s of stability, the
15 weight of the table being carried by the cables. On re~
lea~e of the tension means, the le~s can be collap~ed
again~t the und~rside of the table top. The assembly
is then reduced to a flat volume.
The elements o~ the table support structure are
20 arra~ged in uch a way that the top is prevented from
twisting, swaying or moving vertically by the
txiangulations formed between the support struts, tha
top and the ten~ion members. In order for the top to
remain stabl~ Qv~r time in spite o~ ~mall changqs in
25 le~th of the tension member3 due to ~reap or tempaxatur~
~hange3 a spring elemsnt must ba introduced inta the
~y~tem~ In one form of the invention thera is a coil
~pring situate~ adjacent to the pre-str~sln~ means. The
~pxing m~y be placed anywhere ln the table ~upport
30 ~xuctuxe. In ano~her embodiment, the ~prl~g ~ay bq ~h~
oamb~r~d tabla top itself, or in a s~ ur~her
embodiment th~ ipring may be part of the s~rut el~ment~.
On~ partiaular advantage c~ this typ~ o~ table
~truatur~ i9 ~ha~ it may be easily and aompactly
35 dl~a~embled ~ox ~orage or ~hipmQnt. Thi~ i~ don2 by
relea~ing a pre-~r~ssing davice ~o that th~ ten~ion
el~me~ beceme slack and the leg~ or 3~rut~ may be
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displaced from their normal position to one in which they
lie flat against the table top. The flexible tension
members may also be placed flat against the top for the
~ame reasons.
In order that the present invention may be more
clearly understood and readily carried into effect,
embodiments thereof will now be described with reference
to the accompanying drawings, in which
Fig, 1 shows a perspective underside view of
14 an assembled table of one embodiment of the invention,
~ig. 2 shows the same table in a perspective
end view,
Fig. 3 shows a modified arrangement for the
lower cables,
Fig, 4 is a perspective view from underneath
showing the manner in which the points of articulation
can be moved along the underside of the table,
Fig, 5 shows a detail view to a larger scale ~f
part of Fig. 4 slightly modified,
Fig. 6 is a s~ctional end view of the tracks
along which the points of articulation can be moved,
taken along line IV-IV in Fig. 4,
Fig. 7 is a perspective view of a further
embodiment of the invention,
Fig, 8 is a similar view of a further embodiment,
Fig. 9 is a perspective view of yet anoth~r
embodiment,
Fig. 10 shows the folding structure of Fig. 9
collap$ed into a bundle;
Fig. 11 shows an enlarged view of one form of
; a component of the embodiment of Figs. 7, 8 and ~,
Fig, 12 is a perspective view from below of a
further embodiment of the invention,
Fig. 13 is a perspective view from above of
35 the embodiment shown ir. Fig. 12,
Fig. 14 is a perspective view from above of a
further embodiment,
Fi~. 15 is a perspective view from below of the
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embodimQrlt sh~wn in Fig. 14,
Fig. 16 is an enlarged view of a detail o
the embodiments ~hown in Figs. 12 to 15,
Fig. 17 is a section taken along line XVII - XVII
5 of Fig. 16,
Fig. 18 is an enlarged view of a further de~ail
of the embodiments shown in Figs. 12 to 15, and
Fig~ 19 is a section taken along line XIX - XIX
of Fig. 18.
Referring first to Figs. 1 and 2 of the drawings,
the folding table o~ ~he invention includes a generally
planar table top 10~ In its preferred form, the table
top is reatangulax, ?he table top may also be oval, or
even square ~r roun~l
Th~ ta~le top can be made rom plywoodO
laminated wood ar plastic, fiberglass, glass or steel
or o~h~r mate~ial which has sufficient strength whilst
being capable of holding a pre-camber and will not break
when flexed against the pre-camber or bow under tensi~n
20 of the cables.
Th~ top is supported at each end by a pair ~f
splayed legs or struts 11, coming together at the top
at a point of articulation 12.
Th~ points of articulation a~e preferably
25 located inwards from the narrow end$ lOa o~ the table
top by a distance which is approximately e~ual to one
~ixth of the total ie~gth of the table top.
The lower ends 13 of the legs 11 rest o~ the
~loor. Th~ four table legs are all identical in
30 s ructure. They axe preferably made o~ steel tubing
about 33 inches in length so that in its assembled state
the ~eigh~ o~ the ~able will be the usual 29 inches above
floor level.
The lower ends 13 of the legs are interconnected
35 by a net~ork of cabl~s in the form o a double Y. The
central member 14 ~f the double Y rests on the floor and
ex~ends vertically below the longitudinal axis of the
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table top. The end3 o~ the central member 14 are each
joined at points 14a to shorter end eahles 15 which in
turn are suitAbly joined to the lower ends 13 sf the
ta~l~ legs. The joints 14a of cables 14 and 15 forming
5 the points o~ the Y lie vertically below the point~ o~
articulation 12. The shorter cables 15 al~o rest on
the floor ~nd are generally in the ame plane as the
central member 14. This lower plane is parallel to and
~ub tantially co-extensive with the plane o~ the table
10 ~op,
In *he mQdified arrangem~nt o Fiy. 3, the
lowex netwoxk of cables 18 is in the ~orm of a rectangle
extending between th~ lower ends of the table l~g8.
The as~embly iq compl~ted by vertical ~ables
15 16 extending ~rom each corner 17 of the table top to the
lower end 13 of the corresponding table leg 11. The
vertical cables 16 may be in one piece with the short~x
end cables 15 and run through a suitabl~ opening or
~rxule or a grooved passage locat~d at ~he l~wex leg
20 ~nd~ 13, In this manner, a sexie~ o~ t~ia~gl~s axe
fo.rmed a~ ~a~h corn~r with the longer 91~9 CQn3titUted
by l~gs ll and v~r~ical ~a~les 16. The sh~rt~x ~id~
o~ e~h o~ these triangle~ is constltute~ ~y ~ e
~unnin~ from the coxn~xs 17 o~ the tabls ~op ko th~
25 p~ink~ ~ arti~ulatlon 12.
ThQ advantage o~ having t~e ~ble~ int~
~on~e~ing ~h~ lowe~ Qnd~ o~ the le~ in th2 foxmation
o~ ~ doubl~ Y is hak th~ pexs~n Qr pex~ ting at
~ tabl~ have g~ater ~reedQm ~o mov~ their lsg~ and th~
30 l~s Q~ th~ ahair will not i~ar~ere wi~h ~h~ a~blas~
The ~a~m s~w~ ln ~ig9. 1 ~n~ ~ i9 ~hus more sui~a~l~ a~
dining rG~m t~le. ~ow~ver~ mu~h ~he ~ama e~e~k i~
~b~ ed by arrangin~ ths lower cables 1~ ha æo~m
~ a ~eatan~le as show~ in Fig. 3; this e~hodim~t ~lng
35 mOX2 ~uitabl~ ~s a a~ e ~able~ Flgc 3 also make~ it
olear h~w ~h~ sp~c* b~waen the ~bl~ ~p, lowex ~ble~
18 a~d v~ti~al cabl~ 16 ~in~$ a rectangular
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parallelepiped or brick-shaped volume which imparts to
the whole structure great strength.
The cables are placed under tension by a
pre-stressing device which can be in the form of a tuxn
5 buckle 25 and spring means 26. This spring compensates
for small changes in length of the tension cable due to
creep or temperature changes. In the Figs. 1 and 2
embodiments, the spring 26 is situated in the central
member 14 adjacent to the turn buckle or other pre-
10 stressing means. However, the springs may be placedanywhere along the tension cables, or several springs
may be used where the cable is in several parts.
When the table top is pre-cambered or bowed
with the shorter ends lOa pointing upwards in the
15 unstressed state, the tension imparted in this way to
the cables may be adequate and the spring elements could
be omitted.
When the cables are under tension, the legs 11
are und~r compression and act as struts. When stressed,
20 the triangles formed at each corner by legs 11 and
vertical cables 16 impart to the whole structure a great
deal of firmness preventing the^table structure from
twisting, swaying or moving vertically.
In the Fig. 1 embodiment, the tu:rn buckle 25
25 or quick force release device (such as a Pelican hook)
can incorporate a quick release for the pre-stressing
device. This ~uick release device may be like the lever
action in a ski binding. By releasing the pre-stre~sing
device, the tension elements become slack ~as shown in
30 Fig. 4) and the legs may be displaced from their normal
position to one in which they lie flat'against the
underside of the table 10. The table can then be stored
away occupying very little space.
In the arrangemen~ shown in Figg~. 3 and 4,
35 the upper ends of the table legs come together at pin
joints 19 which are located at the outer ends of slats
20, 20a which in turn are joined by hinges 21' to sliding
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;pin joint plate 19. The inner ends of the slats are
movably joined together by a hinge 21. The slats move
in U-shaped guides 22 fastened to the underside of the
table top, see Fig. 6.
$ It will be seen tha~ by manually pushing the
hinge 21 upwardly against the underside of the table top
in the direction of arrow 23 (see Figs. 4 and 5), the
upper ends of the table legs will be moved away from
each other~ In this manner, the vertical cablas 16
10 and the lower network of cables 14, 15 or 18 will be
placed under ension.
To collapse the table, the procedure is
reversed and all that is required to release the
tension in the cables is to manually move hinge 21
15 downwardly. To hold the slats 20, 20a in the upper
position, a simple catch or latch (not shown) can be
provided on the underside of the table top. Or a
preferred way is to use an over-center hinge, so that
hinge 21 in the tensioned state lies against the
20 underside of the table top over the horizontal plane
of hinges 21', see Fig. 3.
The table top 10 in its untensioned state
may have an in-built camber, bow or concavity with the
ends of the table top above its center. The camber 10X
25 ~shown in broken lines in Figs. 1 and 3) can be quite
slight and does n~t amount to more than 1 or 2 inches
in a 6 foot table. However, in this manner, on applying
tension to the vertical cables 16, the table top will
be flexed in the opposite direction so that in the
30 tensioned state, the table top will generally be quite
flat in~its horizontal plane. The camber will thus
.
compensate for changes in length in the cables due to
~; ~ temperature variation~ or wear and the spring 26 can be
omitted.
Another manner of moving apart the points of
articulation is to arrange the pin joints 19 (holding
;~- together the upper ends of the splayed legs 113 on female
'
- 9 -
threaded slides which move in U-shaped guides mounted on
the underside of the table top. A spindle with opposed
threads on its ends engage in these slides~ The spindle
has a square end adapted to be engaged by a crank (not
5 shown).
In the Fig. 7 modification, the table top 10'
sits loosely on the supporting framework formed by the
cables and struts~ In this system, the supporting frame
take~ all stresses and strains and the table top 10 may
10 be made from plate glass, marble or other rigid material.
The supporting framework includes two points
of articulation 12' located below the underside of the
table top approximately midway between the plane of the
table top and the floor. The points of articulation are
15 again located inwardly from the shorter end of the table
top by a distance which is roughly equal to one sixth
(1/6) of the total length of the table.
Two pairs of splayed legs or struts lla-llb,
llc-lld in V~formation extend from each point of
20 articulation 12'. Legs lla-llb form the lower pair
extending from the point of articulation to the floor.
Struts llc-lld form the upper pair. The ends
of the upper struts at either end of the table form
four supporting points 31 for the loose table top 10'.
25 The poi~ts of articulation 12' are held together by a
horizontal bar 32 located vertically below the longex
axis of the table top. The upper legs or struts llc, lld
may be shorter than the lower legs or struts lla, llb
so that the horizontal bar 32 will occupy a position
30 which is closer to the underside of the table top than
the floor. Such slight variations in length of the legs
or struts and their angular disposition may be dictated
by aesthetic or structural considerations, but will not
affect the basic stability and function of the supporting
35 structure.
The upFer free ends 31 of legs or struts llc-lld are
joined by straight runs of an upper cable 3S which follows
--10--
a yenerally rectangular outline.
The lower corners 36 with which the lower legs
or struts lla and llb rest on the floor are joined by
a network of cables 14', 15' in the form of a double Y
5 which is similar to the tension cables described and
shown in Figs. 1 and 2. Alternatively, the lower network
of cables could have the rectangular configuration shown
in Fig. 3.
The upper ends 31 and lower ends 36 of the legs
10 or struts are joined by vertical cables 16'. The cables
pass through holes or ferrules or grooves at the end of
~he legs. The cables 14', lS', 16' and 35 may be run
through ends 31 and 36 along different routes which will
readily suggest themselves to the designer.
As in the Fig. 1 embodiment, a quick force
release or quick tensioning device 25' is located at a
suitable point or points in the cable network, preferably
at a point along central cable 14'. The central cable
may (but need not) include a spring 26 to take up slack
20 in the cables.
ThP arrangement shown in Fig. 7 has the
disadvantage that if a heavy load is placed in the middle
of table top 10', this may flex downwardly and the table
is subject to swaying. To overcome this, in the
25 embodiment shown in Fig. 8, an additional pair of
struts 38, 39 in V-formation is joined to struts lla-lld.
Struts 38, 39 at their upper or outer ends
are joined at points 42 to the corresponding ends of
the struts rising upwardly from the other point of
30 articulation. The run of the upper cable 35 along the
longer side of the table passes at point 42 through
openings in the abutting upper ends of these struts.
The assembly is completed by a triangle of cables
43a-43b-43c with the lower apex 44 ]oined to triangular
35 ground cables 45a, 45b, 45c running through the lower
ends of struts lla, llb.
In this fashion, the ends of six cables, 43c,
43b, 45a, 45b, 45a' and 45b' come together at apex point
44 which is preferably located about 4" above floor
level. It will be seen that if in this embodiment a
load is applied to the middle of the table top along
5 the l~ne joints points 42, any tendency to rotate the
structure out of true will be resisted by struts 38, 39
and the triangular network of cables linked therewith.
In the Fig. 8 embodiment the horizontal bar
may be in two piecas 32a, 32b one sliding telescopically
10 within the other. A spring catch or umbrella snap 46
secures bars 32a, 32b at the desired spacing.
The folding structure shown in Figs. 9 and 10
uses a generally rectangular canvas top 50 which is
stretched between the upper ends of struts llc, lld
15 and 38, 39 reaching upwardly from each point of
articulation. The term "canvas" top includes any
suitable woven or other sheet material or mesh. The
"canvas" top thus combines the supporting function of
table top 10 and the tensioning action of the upper
20 cables 35 in the Figs. 7 and 8 embodiments. The edge
of the canvas 50 under tension will assume the ~lat
catinary shape shown in Fig. 9. A quick force release
device 51 is loca~ed in one of the lower cables 52
which interconnects the lower ends of lower legs lla,
25 llb. The lower cable 52 may follow the double Y of
Fig. 7 or the cables could have the rectangular
coniguration shown in Fig. 3. The system of struts
and cables could also follow the Fig. 8 configuration,
where the upper horizontal cables could be replaced
30 by a "canvas" top.
The arrangement of the legs or struts is
similar to the Fig. 8 embodiment. The horizontal strut
is again in two parts 53, 54 telescopically sliding
within each other and held together by an umbrella type
35 snap 55.
To collapse the structure, the ~uick release
device 51 and the umbrella snap are disengaged. The legs
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are folded towards each other. The upper ends of the upp~r
struts need no~ be disengaged Erom the canvas which
folds up between the legs as shown in Fig. 10. The
folded bundle occupies approximately 2% of the space of
5 the structure in its assembled state shown in Fig. 9.
Because of the small storage space required,
the folding structure of Figs. 9 and 10 may find use as
a camp bed or scaled upwardly could form part of a tent,
water catchment or other military or strategic uses
10 might sugges~ themselves.
In the ~bove description the points of
articulation are generally in the nature of hinges or
pivotal joints. In a further form of the invention
(Fig. 11), these joints could be made from semi-rigid
15 castings (e.g. fiber-reinforced nylon or aluminum
castings). These joints would then consist of a central
piece 60 with a number of integral stubs 62 on which the
struts lla-lldr 53 would be detachably mounted. The
term "articulation" as used herein is thus intended
20 to cover fairly rigid joints in addition to movable
joints,
In the embodiment shown in Figures 12 and 13
legs 111 depend from tne underside of a table top 110.
The legs are arranged in pairs at opposite ends of the
25 table and are articulated to the table top at locations
(112) on the longitudinal center line of the table and
inwardly of the short sides thereof. In the embodiment
shown in the drawings each pair of legs is a single
member which takes the form of an inverted V with its
30 apex articulated to the underside of the table top and
the r~mote ends forming the feet of the legs. Those feet
are interconnected by a network of cables in the form
of a double Y in a manner similar to the embodiment
shown in Figure 1. To this end a central member 114 of
35 the Y is arranged to rest on the floor and is joined
to shorter end cables 115 which pass through the feet
of the legs and extend upwardly as vertical cable runs
~ 1 ~t3~ ~ ~
116 which are anchored to the corners of the table
top.
With the table parts erected in the
operative position shown in Figures 12 and 13, the feet
5 of the table legs are located below the corners of the
table top and the network of cables imparts the desired
rigidity and stability to the table.
Figures 18 and 19 show, on an enlarged scale,
how the cables 115, 116 pass through ~he feet of the legs
10 111. To this end each leg Ill is bent outwardly at the
foot portion to lia on or parallel to the floor or
other restLng surface and then upwardly at the
extremity of the foot end. The cable 115 passes
through an aperture in the leg portion and then through
15 the terminal portion of the foot and upwardly for
anchoring to the corner of the table top.
If desired, glide clamps 100 can be snapped
onto the feet portions which extend parallel to the
floor or other support surface~
Instead of having tensioning means included
in the cable network, the apex of each pair of legs is
articulated to the underside of the table top by an
individual tensioning means 150.
In this individual tensioning means 150, which
25 is shown in enlarged detail in Figures 16 and.17 of the
drawings, a strap 151 is looped around the apex of the
pair of legs 111 and the ends of the loop are secured
by fastening means such as, for example, a rivet 152.
The remainder of the strap has a track 153 extending along
30 the length thereof to engage a rotatable worm 154. The
worm 1S4 meshes with the track 153 and is supported in
position by a housing 155 formed at the end of a strip
156 of metallic or other suitably rigid material. The
strip 156 lies along the underside of the table top 110
35 and is se¢ured by one or more screws 157 or other suitable
means.
A key slot 158 is provided in a head portion
159 of the worm 154. It will be appreciated that this
~:7
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tensioning m~ans is effectively a flattened hose
clip or jubilee clip and that rotation of the worm 154
will draw the strap 151 longitudinally along the under~ide
of the table top and thereby create the desired tension
S in the legs and network of cables.
Figures 14 and 15 show a modification of the
embodiment shown in Figures 12 and 13. Figures 14 and
15 show a table topllO' which is square rather than
of elongated rectangular shape and which has legs 111l
10 articulated (112') to ~he underside of the table top in
the central region thereof. Articulation of the legs
111' to the underside of the table top 110' is through
tensioning means 150' of the type described with
raference to Figures 12 and 13 and shown in detail
15 in Figures 16 and 17.
A network of cables is again utilized and in
this case comprises cables 115a which interconnect the
feet of diametrically opposed legs 111'.
As in the embodiment of Figures 12 and 13, the
20 cables pass through the feet and extend upwardly to
anchorages on the table top. However, unlike the
embodiment o~ Figures 12 and 13, the upwardly directe~
cable portions 116a are not single cables but, instead,
twin cable lengths which diverge from the feet of the
25 legs to spaced anchorages 117 which anchorages are, in
turn, spaced from the corners of the table top. In
this manner, rigidity and stability against rotational
deformation of a square table is enhanced by the
triangular configuration adopted by the cable lengths
30 extending upwardly from the feet of the legs.
As explained, the desired tension is imparted
to the network of cables 115a, 116a by the individual
tensioning means 150'. ~;By selectively adjusting means
150, 150' it is possible to ensure that the table top
35 110, 110' is level even when the feet of the legs rest
on an irregular floor surface.
In the majority of the above discussed
, ~ .
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embodiments, the ~et of the table legs are located
directly beneath the c~rners of the table top. Thi~,
however, is not always the case and Figures 14 and 15
show an assembly where the feet of the legs are not
5 disposed directly beneath the corners of the table top~
L ~
