Note: Descriptions are shown in the official language in which they were submitted.
i3
is inyell~iOII rela-~es ~o ~n arch ~oXming assem~ly.
Uni-t~d t;in~jdoIIl Paten-t llo~ 1,206,706, dated June 14r
195S, "~rched ~ui:ldiny ~lembers~ .J. Cohenl discloses a buil-
ding a,sen-,bly cor,~rising an elongated building mel~er with fle-
xible tensioniny member connected thereto at spaced positions
tllerealorlg and in spaced relationship -therefrom 50 that on
app]ying a tension to the flexible tensioning member the buil~
ding member is cambered upwardly and -thereby erected.
While the archecl building member devised by E.J. Cohen
10 has no doubt been found to be useful in some areas it has been
found by the applicants to have a drawback in that the elongated
building member can only be cambered to a limit.ed extent and
so the arched buildiny member cannot be used whe.re a building
having a reasonable degree of .internal height is required.
In United States Patent No. 3,986,541, dated ~ovem-
ber 26, 1974, "Arched Building Assembly Formed of Resiliently,
Flexible Members", E.J. Cohen, discloses an improvement on the
arched building member, comprising a building assembly for
erecting an arched, resiliently flexible building member in
20 which the building mernber consists of two sub-members which
are interconnected by a resiliently flexible connector capable
of greater flexure than the sub-members so that, on erection,
the building member has an upwardly pointed shape. Flexure of
the flexible connector, and upward cambering of the submembers
is effected by loading the submernbers in compression with loa~
ding cables which interconnect longitudinally spaced parts of
the building member and are raised with the buildiny member by
bracing means which maintain the cables in fixed spaced rela-
tionship to intermediate parts of the building mei~er. Fle-
30 xure in both the reslliently fïexible connector and the sub-
mel~ers occurs simultaneously, but to a greater extent in the
383
.res:i].i,rl~ ~r:~sn~.r. ~cld:itio:nal loa~inc~ ca~les maX be pro~ided
for flexirl~-the suh-m2mbers i`ndependantly.
~ J~ile the ~rched huildiny assem~ly of Cohen does in-
crease the ir-bernal heigh-t of the ~uilding ~y most of the de~-
flection occurring in the resilientl~ flexible connector there
is still a problem in that the arched building assembly, ~rhen
erected, assumes the form of a slightly cambered, splayed, in-
verted V-shape and so additional height is only provided at
the center of the building.
Thus there is still a need for an arch forming assem~
bly which provides adequate internal height over a reasonable
portion of the buildiny floor space.
According to the present invention there is provided
an arch forming assembly, comprising:
a) a substantially flat flexible mernber for bendins
to the shape of the curved arch,
b) a plurality of tension line guides attached to
the flexible member at spaced intervals to a side of the fle-
~: xible member which will define the inside of the arch so that
20 tension line guides will be spaced therearound,
c) a first tension ].ine attached at one end to afirst side portion of the flexible member and threaded through
even numbe~ tension line guides.-only, counted from the sald
first side portion to a second side portion opposed thereto,
and attached at the other end to the second side portion,
d) a second tension l.ine attached at one end to the
first side portion of the flexible member and threaded
throush odd number tension iine guides only, counted from the
said first side portion towards the said second side portion,
30 and attached a.t the other end to the said second side portion,
and
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e.) rmeans.:Ec)r tens.ioniny th.~ said ;Eirs.~ and second
t^nsion lines to bend the flexible member to the ~hape of the
cu-ved arch.
In the accompanying drawings lrrhic~ illustratel by
way of e~ample, en~odimen-ts oE the present invention,
Figure 1 is an isometric view of an arch forming
assem~ly in a collapsed form,
Figure 2 is an end vie~ of the arc.~ formi`ng assemkly,
shown in Figure 1, erected,
Figure 3 is an enlarged perspective view of a means
for tensioning first and second tension lines shown in Figures
1 ana 2, at the right hand end of a flexible memher,
Figure 4 is a side view of a tension line guide
and a portion of a flexible member,
Figure 5 is a sectional end view of Figure 4 along
Figure 6 is an enlarged perspective view of the first
and second tension lines shown in Figures 1 and 2, joined at
the left hand end of the flexible member and passing around a
.~ 20 pulley at the joint,
Figure 7 is an end vlew of a different arch forming
assembly to that shown in Figures 1 and 6,
Figure 8 is an end view of a portion of the arch
forming assembly shown in Figure 7,
Figure 9 is an end view of a portion of a different
arch forming assembly to that shown in any of Figures 1 to 6,
in a collapsed condition,
Fiyure 10 is an end view of the arch forming assembly
shown in Figure 9, in an erected condition,
Figure 11 is a similar end view to that shown in Fi-
gure 10 with the tension line lbngths omitted,
Figure 12 is a similar end view to that shown in Fi-
gure 10 ~itl~ the ~-lrch forming asselllbly being used as a Eormwork
for concr~.~, alld
Figure 13 is an end view of a corner support for the
arch .~orming a~s~nbly sho~n in ~iy~re. 12.
~ e:E~rrin~ to liigures 1 to 6, t~ere are shown three
arch forminy assemblies 1 -to 3~ each comprising:
a) a substantially flat flexible member 4 for bending
to the shape of the cur~ed arch shown in Figure 2,
b) a plurality of tension line guides 6, 6a, 6b and
10 6c, shown in detail in Figures 3 to 6, attached to the flexi-
ble member 4 at spaced intervals on a side of the flexible mem-
ber 4 which will form the inside of the arch so that tension
line guides 6, 6a, 6b and 6c will be spaced therearound,
c) a first tension line 8 attached at one end to a
first side portion 10 of the flexible member 4, by means of
tension line guide 6b, and threaded through even number ten-
sion line guides 6 only, counted from the said first side por--
tion 10 towards a second side portion 12 opposed thereto, and
attached at the other end to the second side portion 12, in this
20 embodiment by means of tension line guide 6c,
d) a second tension line 16 attached, in this embo-
diment by means of tension line guide 6b, to the first side
portion 10 of the flexible member 4 and threaded through odd
number tension line guides 6 only, counted from the said first
side portion 10 towards the said second side portion 12, and
attached at the other end to the said second side portion 12,
in this embodiment by means of tension line guide 6c, and
e) means generally designated 18 in Figure 3 for -
tensioning the said first and second tension lines 8 and 16
30 to bend the flexible member 4 (shown chain-dotted in Figures 3
and 6) to the shape of the curved arch.
The tension lines 8 arid 16 in this embodiment are
lla~Z~3
helica]l~ strclrl~led st~el cable~ and are in one con-tinuous
]ellgth wl~ is a-ttached to the first side portion 10 by
looping aroun~ a freely rota-table pulley 20 (Figure 6) of
the tensio~ line guide 6b. The tension line guide 6b com-
prises the pulley 20 mounted to freely rotate in a bracket
22 securely attached to an end portion of the flexible mem-
ber 4 and a se-t screw 23 for locking the first and second
tension lines 8 and 16 to the bracket 22. In other embodi-
ments, the tension line guide 6b comprises an eye bolt of
10 the type shown in Figures ~ and 5, attached to the flexible
mernher 4 in a secure manner.
The tension line guides 6 and 6a (Figures 4 and
5) each comprise an eye bolt, preferably provided with a
set screw 21 or other locking device for clamping the ten-
sion line 8 or 16 against slipping therethrough once the
flexible member 4 has assumed the shape of a curved arch.
The tension line guide 6c (Figure 3) comprises
a tube 23 which is attached to the flexible member 4 and has
a set screw 24 or other locking device for clamping the ten-
20 sion line 16 in the same manner as the set screw 21 (Figures4 and 5). Tension line guide 6c has a bracket plate 26 wel-
ded thereto. The end of the tension line 8 is secured to
the bracket plate 25. The bracket plate 26 is welded to a
base plate 28 upon which is mounted a variable speed elec
tric motor and slipping clutch gear reduction unit 30 having
a winch drum 32 mounted on its driving shaft. l'he end of
the tension line 16 is attached to a winch drum 32.
The flexible members 4 of each of the arch forming
assemblies 1 to 3 are joined by transverse members 34 to 37
130 to form one struc-ture, and a ~lexible covering sheet or roof
;covering 38 o, for example, a synthetic plastic material is
preEerably placed over and tied to the struc-ture when it is
in the f~,iit:tened condition shown in Figuxe 1.
The structura:L member ~ may be integral with the
roo~ covering 38 where the entire unit is cons-truc-ted from
iibreglass or other suitable ma-terial. On erection, sec-
-tions o~ the building comple~e with structural member and
roGf covering are raised in position. The erected sections
can then be sealed at the joining points to provide a con-
tinuous leak-prooE building. Longi-tudinal members, although
fewex in num~er, could be provided to establish longitudinal
10 in-teg,~ity.
In operation the flexible members 4 have or are
given a slight curvature in the direction in which they are
to be arched while lying on the ground or a foundation. The
members 4, if not provided with a slight curvature can be
deflected to have one by providing support blocks or jacks
underneath the members 4 before the flexible covering sheet
8~ is placed over and tied to the structure.
Each electric motor and slipping clutch gear re-
duction uni~ 30 of each of the three arch forming asseniblies
20 are simultaneously driven to tension the first and seconcl
tension lines 8 and 16, until the flexible members 4 have
been defle~-ted to form an arch as shown in Figure 2. ~Jhen
the flexi~le member 4 has been deflected to form the desired
arch as shown in Figure 2 each set screw 21 and 24 is tigh-
tened to lock the first and second tension lines 8 and 16
to each tension line guide 6, 6a and 6c, and the set screw
23 is tightened to lock the first and second tension lines
8 and 16 to the bracket 22. Locking the first and second
1tension lines 8 and 16 in this manner is preferred because
!30 it provides the erected structure with additional strength
and rigidity.
When it is necessary to collapse the arch forming
-- 6 --
asse!nblie~i 1 to ~ the set screws ~.1, 23 and 24 are unscrewed
and -the slir~r)in~, clul_ch of the electrlc motor and slippiny
clu~ch unit 30 is used to gently collapse each flexible
member 4.
The flexible members 4 may be strcssed within the
e1as-tic limit for re-usable structures or beyond the elas-
tic limit for permanen-t or semi-permanent structures.
The form of arch obtained depends on the spacings
between the tension line guides 6, 6a, 6b and 6c. If the
10 spacings between the tension guides 6 and 6a at a central
; portion of each flexible member 4 are enl.arged or made
smaller than the spacings of the remainder, then the local
curvature at this central portion is either increased or
decreased thus permitting a modified shape resulting in
either greater head room and a shorter span or smaller head
room and a larger span.
t In different embodiments of the present invention
the tension line guides 6, 6a, 6b and 6c are distr.ibuted .^~
along only a portion of the length of each flexible member
20 4 so that in the erected position each flexible member 4.
has, for example, portions at each end that have not been
deflected. These portions may have greater stiffness than
the portions that are deflected or may be stiffened after
the structure has been erected.
Further rigidity may be obtained by moving the
lower ends of the flexible members 4 a little further apart
once the first and second tension line lengths 8 and 16
have been clamped to the tension line guides 6, 6a, 6b and
6c.
; 30 If desired additional aid can be provided in the
erecti.oll stage by drawing the ends of the flexible members
together by, for example, an additional cable extending
-- 7 ~
t~3
directly between these ends. '~his wi:ll reduce the load re-
~uir^d in ch~ fi-r-;~ and second tension lines to deflect the
flexible members 4.
In different embocliments of -the present invention,
the firs~ and second tension line lengths 8 and 16 have
their le~t hand ends secured to -the flexible member 4
instead of being joined and passed around pulley 20. In
this embodiment the right hand ends of both the first and
second tension line lengths 8 and 16 are tensioned by, for
10 example, a winch mechanism such as a drum actuated with a
lever through a pawl or ratchet mechanism to prevent slip-
ping. Tlle pawl or ratchet device is preferably attached to
the flexible member 4 making the whole assembly self-contained.
The embodiment shown in Figures 1 to 6 is particu-
larly suitable for small buildings such as, for example,
small home-style greenhouses and portable or temporary
enclosures.
In Figures 7 and 8 similar parts to those shown in
Figures l to 6 are desiynated by the same reference numerals.
In Figures 7 and 8 the first and second tension
lines 8 and 16 are secured to the flexible member 4 at ten-
sion line guide 6c and pass through the tension line guides
6, 6a (Figures 4 and 5) and 6c (Figure 3) and are secured
therein by the set screws 24. In this embodiment the ten-
sioning means 18 is not provided. The left hand ends of
the tension line lengths 8 and 16 are secured to the fle-
xible member 4.
The flexible member 4 is initially flat and is
e ected by progressively insertiny spreader bars 40 -to 46,
30 starting with the spreader bar 40, as shown in Figure 6 at
the positions or the intermediate tension line guides 6 and
6a to deflect the tension line length 8 or 16 not passing
0~33
theret~lrougl-l. Thus the flexible member 4 is progressively
deflec-~ed fr~ln the tension line leng-ths 8 and 16 to form
an arch. The tension line lengths 8 and 16 are then
locked in the tension line guides 6 and 6a by set screws
or other locking devices. The spreader bars ~0 ma~ also
be secured to the tension line lengths 8 and 16 to provide
additional rigidity to the s-tructure. Irhe degree oE cur-
vature imparted to the flexible member 4 depends on the
lengths of the spreader bars 40 to 46 which may be dif-
10 ferent to produce an arch of a particular shape.
As with the previous embodiment the ends of the
flexible member 4 may be drawn closer by, say, a cable~ex-
tending across the gap between them to assist in this in-
stance in the installation of the spreader bars 40 to 46.
Further, as with the previous embodiment, further
rigidity may be obtained by moving the lower ends of the
flexible member 4 a little further apart following the
clam~ing of the tension line lengths 8 and 16 at the ten-
sion line guides 6 and 6a.
The flexible member 4 may be deformed within the
elastic limit or may be deformed beyond the elastic limit
in which case it will be capable of carrying a greater load.
In Figures 9 to 11, similar parts to those;shown
in Figures 1 to 6 are designated by the same reference
numera. 5. and the previous description is relied upon to
describe them.
In Figures 9 to 11 the spreader bars 48 to 54 are
pivotally attached at one end to the intermediate tension
line guides 6 and 6a by hinges 55 to 5S shown in Figure 9,
30 and have slots at the other ends through which the tension
]ine iengths 8 and 16 are held captive in a freely slidable
manner. In this embodiment the tension line ler.gths 8 and
16 are each clnchored at both ends to the flexible member 4
and are ~ u~e~ -to the tension line guides 6 and 6a by,
for e~ample, set screws (not shown) when the flexible
member 4 has been de~lected to form an arch.
The spreauer bar 48 closest -to the first side
portion 10 is at-tached thereto by an anchor s-tring cable 40
and each spreader bar 49 to 54 subsequently to the spreader
bar 48 in the direction of the second side portion 12 is
secured to the preceding spreader bar by one of the draw
10 string cables 62 to 67. The spreader bar 54 which is clo-
sest to the second side portion 12 has a draw string cable
68 attached thereto which is threaded through the tube 23
of the tension line guide 6c and is attached to the means
generally designated 18 for tensioning the first and second
tension lines 8 and 16, which is preferably a ratchet ope-
rated device.
; In operation the draw string cable 68 i5 ten-
sioned to draw the spreader bars 48 to 54 from the position
shown in Figure 9 to the position shown in Figures 10 and ~ -
20 11 where further movement of the spreader bars is prevented
by the anchor string cable 60 and the draw string cables 62
to 67. This movement of the spreader bars tensions the
first and second tension lines 8 and 16 which causes the
flexible member 4 to be deflected to the desired arch. The
draw string cable 68 is then clamped in the tube 23 (Figure
3) by means of the set screw 24 or other locking device.
The lengths of the anchor string cable 60 and
each draw string cable 62 to 67 are chosen bearing in mind
that for good structural design:
i) they control the angles betw~en the fleY~ible
member 4 when deflected and the spreader bars 49 to 54 which
are preferably such that the spreader bars 49 to 54 extend
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11~2~2~33
s~st~n~ y l-L~dially inwards from the curva-ture of the
arch, and
ii) preferably -the length of each dra~ string
cable 62 to 67 equals the arcuate leng-th of the deflected
portion of the flexible member 4 between the two spreader
bars connected by -that draw string cahle. This may also
determine the position along each spreader bar 49 to 54
that the left hand end of a draw string cable is connected
thereto.
The embodiment shown in Figures 9 to 11 is par-
ticularly suitable for use in large, demountable buildings,
semi-permanent and permanent buildings and as formwork for
reinforced concrete where curved formwork is required, e.g.
arches, domes and etc.
~ n Figures 12 and 13 similar parts to those shown
in Figures 9 to 11 are designated by the same reference nu-
; merals and the previous description is relied upon to des-
cribe them.
In Figures 12 and 13 the spreader bars may be -
20 actuated by anchor string cables as described witn referenceto Figures 9 to 11 or in the form of fluid pressure actuated
jacks 70 to 73. When fluid pressure actuated jacks 70 to
73 are used, they are secured to the flexible member in
such a manner that they remain normal thereto at all times.
.~nchor string cables are not necessary with fluid pressure
actuated jacks 70 to 73 and the first and second tension
line lèngths 8 and 15 are secured to the free ends thereof
in a freely slidable manner. The tension line lengths 8
and 16 are each secured at both ends 74 and 76 to the fle-
30 xible member 4. The ends 74 and 76 of the flexible member~ aLe provided wi-th angle supports 78 and 80 respectively
which are pivotally attached to the flexible member 4 by
release pins 82 and g4 respectively.
In operation the jacks 70 to 73 are actuated to
cause the flexlble member 4 -to assume the arch without being ..
coupled to the angle supports 78 and 80. The angle supports
78 and 80 are placed upon supports 86 and 88 which the formed
concrete 100 is to span and the flexible member 4 is coupled
to the angle suppor-ts 78 and 80 by the pins 82 and 84 respec-
tively. The concrete is then poured and allowed to harden
to form the concrete 100.
The structure is then released from the concrete
by first temporarily supporting the form, then removing the
pins 82 and 84, and then actuating at least one of the jacks
or increasing the curvature by any other means hence causing
the ends 82 and 84 to move away from the concrete 100 and
thus breaking the bond between the formwork and the concrete.
The form is then removed from underneath the concrete 100
for use elsewhere.
i~
In other embodiments of the present invention,
where the width of the flexible member 4 permits it, one
20 pair of tension line lengths 8 and 16 extend along one
diagonal path across the flexible member 4 while another
pair of tension line lengths 8 and 16 extend along the other
diagonal path across ~he flexible member 4, and the flexible
member 4 can either be given an extra curvature in a width
wise direction or be stiffened to avoid this at least along
the edges.
In some embodiments of the present invention the
first and second tension line lengths 8 and 16 comprise a
single wire.strand of steel or another metal, a plastic
: 30 filament or cord of, for example, superpolyamide.
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