CA1179768A - Unfoldable and foldable mast - Google Patents
Unfoldable and foldable mastInfo
- Publication number
- CA1179768A CA1179768A CA000381566A CA381566A CA1179768A CA 1179768 A CA1179768 A CA 1179768A CA 000381566 A CA000381566 A CA 000381566A CA 381566 A CA381566 A CA 381566A CA 1179768 A CA1179768 A CA 1179768A
- Authority
- CA
- Canada
- Prior art keywords
- mast
- unfoldable
- cams
- foldable
- base
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/1235—Collapsible supports; Means for erecting a rigid antenna
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
- B64G99/00—Subject matter not provided for in other groups of this subclass
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H12/00—Towers; Masts or poles; Chimney stacks; Water-towers; Methods of erecting such structures
- E04H12/18—Towers; Masts or poles; Chimney stacks; Water-towers; Methods of erecting such structures movable or with movable sections, e.g. rotatable or telescopic
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Remote Sensing (AREA)
- Aviation & Aerospace Engineering (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Details Of Aerials (AREA)
- Support Of Aerials (AREA)
- Aerials With Secondary Devices (AREA)
- Tents Or Canopies (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An unfoldable and foldable mast is provided herein which is formed by a plurality of elementary parts. Each mast comprises a first base with "n" sides common to a preceding elementary part, and a second base with "n"
sides common to a following elementary part, two consecutive sides of the first base and the second base subsending an angle therebetween. A number of rods connect together the angles of the bases, the number of rods being equal to the number of sides of the bases. Each rod includes thereof hinges having a degree of freedom in the middle and at the ends thereof, thereby making such rods bondable, the hinges being equipped with stops. Cables are provided to form cross-braces. Finally, a deployment mechanism is provided.
Such an unfoldable and foldable mast is intended to be used more particularly in the space field or to be mounted on light vehicles for erecting telecom-munications antennae, etc.
An unfoldable and foldable mast is provided herein which is formed by a plurality of elementary parts. Each mast comprises a first base with "n" sides common to a preceding elementary part, and a second base with "n"
sides common to a following elementary part, two consecutive sides of the first base and the second base subsending an angle therebetween. A number of rods connect together the angles of the bases, the number of rods being equal to the number of sides of the bases. Each rod includes thereof hinges having a degree of freedom in the middle and at the ends thereof, thereby making such rods bondable, the hinges being equipped with stops. Cables are provided to form cross-braces. Finally, a deployment mechanism is provided.
Such an unfoldable and foldable mast is intended to be used more particularly in the space field or to be mounted on light vehicles for erecting telecom-munications antennae, etc.
Description
` ~ 3L7'~3~fi~
The present inventiorl relates to an unfo]dable and foldable mast of grrat rigidity and great length intended more especially, but in no limiting srnse, to be used in the spacr field, or on light vehieles for erecting telecomrnunications antennar, ete.
In thc! spaee field, the requirements of missions have only been concernrd up to now with masts having either great rigility and small ]ength or great length and ]ow rigidity. Except for a few rare exceptions, rep-reserlted more especial]y by the arms of automatic ]unar vellicles, no con-dition for folding masts has been requirrd up to the present. Aeeordingly, meehanisms of rlldim-ntary d~sign, e.g., pantographs and others, have been used.
Future missions will use high power generations formed from solar panels. In order to be able to use sueh solar panels again, or possibly to repair them on the ground, these panels will have to be unfoldable and fold-able. These panels will be deployed and folded by means of an unfoldable and foldable mast. The large area of the panels involves using masts of great length, oE great rigidity and having a small eneased volume. These new requirements eonsequently demend new concepts.
Although the deseription of the present invention in its various aspects relates prineipally to spaee app]icatinns, this latter is however not limited to these app]ications. The present applieatiorl in its varinls aspeets eould, for example, also b usrl ~or othcr app]icationC.~ ~.g., m.l ts transportable on ]ight vrlli les f)r er(ctin& I ]~comrrlullicati()lls alt n~ e having heights rangirg from a few m~tcrs to s vera] lens ol m l rs.
Unio]dab]e and follable mas~s have b~cn pror)os d in Ihc prior arl, particularly in United States Patent ~o. 3,486,279 issued to James 1. Webb.
These masts, whieh may be rapidly urlfo]dc(l from a fo]decl eondition o~ small volume, eompris( a plurality of inclividually oldable triangular seetion segments, formed by booms whieh are eonneeted together in two and whieh eomprises three longitudinal reetangular faces 1) ld tog Lher by two eables fixed diagonally at opposite corners of the rectallglc, by m ans of springs.
37~
The reetilnglllar sul-faecs of these sc~gments are pivotally eonneetrd together by means of flex;ble gireers, whieh form sides of the reetangles whieh are eurved into eireles when the strueturc is folded and whieh tend to straighten 50 as to assurnt a reetilinrar position when the mast is l~nfolded. Ilowevcr, the unfoldable and foldable masts cleseribed in this patent prescn~, a number of drawbaeks; th(y requirr- a high eonsurnption of energy bceaus( Or the eon-siderablc frietion induec(] in tl-e unfo]ding mcehanisrn, whieh energy must, in gcneral, be supp]i(d by batteries or other generators of thc same type;
a system of great preeision whierl opposcs roLation rnust bc providrd in thr ease of an applieation of the solar generators of tl-e same type; a systrm of great preeision whieh opposes rotation must be provided in the easr of an applieation of the solar generator type; and, they are not very flexible, do not allow variations and eonsequently limit any possibility of optimization.
Objeets of aspeets of the present invention inelude the provision of an unfoldable and foldab~e mast, having a light strueture but nevertheless great rigidity, in whieh the frietion indueed by the deployment operations is very small, whose stability is very high beeause the stresses are dis-tributed along the three axes and whose ease nf storage is improvrd wirh respeet to the prior art struetures by redueing the spaee required by redue-tion of the number of elements staeked on c~aeh othcr.
Thc present invention, in one aspeet, prnvi(l(s an unfollable and foldable mast eonsisting cssertially of a plural-ity ni elel~ tary parts, eaeh of whieh eomprises: a first hilS(' wi~h llnll si(l('':~ CilCIl siCl(' CnrrlF)ri'.ill&
a boom, eommclrl to a preeeding (I(nl(n~ar~ p-,r~; a s(eond IJI;( w-ith n sidcc.
eaeh side eornprising il boom, eornln~l- to a fo] ~ r~ r l( mr ntal y p~ w(~
eonseeutive sides of th- firsL base and the s(enl1cl base sllb~ell(lirlg al) allglc therebctween, a number of rods eonl-l eting togcther ih( angles or th( bascs, the numbcr of r-nds being ecl-lal to the number lf sid s o~ the bascs, the rods ineluding, in thc middlc-, and at thc cnds thcrcof, hil-lgrs haVil1g a dCgr('C
of frecdom, thereby making the rods bendable, th( hing(s eluil-l) d ~ith slopS;
eables forming eross-braees; and a deplnylrlcnt mechan-isrll.
1 ~797t~
By one variallt thereof, the first and second bases have any sym-metrical or unsymmetrical shape, e.g. a triangle, a square, a rectangle, a pentagon, or a hexagon.
By another variant, the rotational axes of the hinges are in di-ferent planes and are inclined by a predetermined angle.
By still another variant, the rotational axrs of thr hinges arr inclinc!d at different angles.
By still another variant, the rotational axes of the hinges of th same girder, betwcen two consecutivc elcmcrltary structures, are inclincd by the same anglc.
~y anotl~er variant, the eables are fixed to the opposite eorners of an elementary structurr by means of memory systems, e.g., by means of flat springs.
By yet a further variant, the rods between two consecutive elemcn-tary structures have a length less than twiee the smallest side of the base, thereby to reduce to a minimum the space required by the mast during storage.
By a still further variant, the hinges are provided with unsymmet-rical stops, thereby making the mast slightly twisted out including cablcs of different lengths placed, thereby between two consecutive booms to mini-mi~e to the maximums as possible deflection of the mast, due particularly to a heat gradient generated by a unidir ctional flow applied to tlle mast.
By a further variant, the cleplo~ment rncchanism comprises sets of cams fixed to a first toothed rirlg, actuat cJ by on -r mol-~ motors.
By a variatiorl thcreof, each se~ o~ cams is rorrrl~d Or ~W(! (~.lmS.
By a further variaLiorl thereof, th nLInlb(!r ol set, of cams is Iqu.
to thr numbrr of sid s which compris thc base.
By yet allotl-lcl- variation thereof, a scconl ring is associatc(l Witl thc driving SCI'CWS of thc firs~ ring, the dri~ing s rews l- ing intcgr31 with a base plate which supports the stored mast, so as to prcvidc gr3lual lcveling of the sLor d part of th mast, ~l~c econd ring carrying tc th or-lly at ccrtain parts of its periphcry so that thr scrcws are only actuate(l by 37~
thc ring during the intervals during which the cams of the sets of cams are not cngagcd witl the e]ements of the stored mast to be deployed.
By a still further variation thercof, the mast includes a system of retractable fingers actuated by the first ring, for retaining non-deployed stored part of the mast on the base plate during the drployment action of the cams.
By a further variant, the mast includes a first projection carried by the base, ovrr which a first cam of the correspondir)g set of cams, movcs, to causc a Sirst dcp]oymcnt of the rod.
By a still furthc!r variant, cach of the mildle hinges of the rocls carries a seconl projection ovcr which the second cam of thc corresponding set of cams move, so as to cause complete deployment of the rod.
By yet a further variant, the first ring also carries folding cams staggered with respect to the sets o~ cams for progressive extraction of the structure of the mast.
In the accompanying drawings, `
Figure 1 shows schematically the successivr phases of deploying a mast in accordance with an aspect of the present invention (Figures la tO
1 c ) ;
Figure 2 shows an example of a mast structure in accordance with an aspcct of the invention, with a triangular basc;
Figure 3 shows schematically mbodimcnts of thc hingcs in wll-icl, thc rotational axcs of thesc latter arc incline(l by a cre(lct(rr~ ecl arlgl with rcspcct to the pcrpen(licular, ~he slop( I) -ing abl( lo b( dil~(rellt depcnding on tll( hinges consil(red (l:igulrs 3a - 3b~;
Figul- 4 is a sch lnatic represelltation of a rrlecl-lallic;rrl lor dcployin,c~
the mast in accc-r(lance with an as~.ccL of tl-le prescnt invention; and Fig7ure 5 illustrates (Figurcs 5a to 5cl) th( mode of operation.
The mast, which forms the subjcct of an aspcct of th(~ prescnt in-vention, is ormccl of rods [L, L ], bc)oms ~, M ] and cross-bra(cs, [e.g.
cablcs C, C~].
11'~.~37~,~
The principlc of the foldable mast will be described hereinafter with reference to Figures la to lc. These Figures represent the different phases of deployment oi a bidimensional mast. This mast comprises two booms [M', M], two cables [C', C~ and two rods [L', L] which are made bendable in the middle and at the cnds thcreof by means of hinges [respectively H1~ H2;
H1', 3l2'; and H1", ll2"].
Figur( la sllows the beginning of thc dcploymcnt. The rods [L', L]
are rnoved contirluously in thc direction of tllc arrows, by rncans of a dcploy-ment mechanisim, not showr~ in this Figllre. I)uring dcployrncTlt, the cab]cs [C', C~ gradually stretch. Figure lb shows a position in W3~iC]l thL cablcs [C', C~ are quite strrtched; the final position, however, has not yet been reached. The movement of the rods [L', L~ continuts further, which causes elastic deformation of the cables [C', C]. This deformation is maximum when the two parts of the rods [L', L] form a straight line. Further movemcnt of the rods [L', 1,] slightly slackens the cables [C', C]. The final postion is reached when further movement is made possible by stops [B1, B1', Bl";
and B2 B2~ B2"] integrally formed with the hinges [H1~ H2: H1', H2'; and H1", H2"] (ser Figure lc). Ihe position 03 the stops ~B1, B1', B1"j and B2, B2', B2"~ is chosen so that a stress rcmains in the cables [C',C].
The stability of thc structure thus obtained is total. ln fact, thc outward rnovemerlt of the rods Ll, L'] is madc virtlla]ly impossiblc by thr prescnce of thr StOpS ~B~, Bl', P,l"; B2, E2', B2"] ancl inwrlrrlrllov~rn~n~
is madc diffi~ult by thc prcslrcss((l cal)lcs [C', (¦.
From t}-le "basic plan( conccr)t" ol îhe mast, c.g.~ a~ SbO~!II ir, ligures la to 1c, it is possit)lc to crcatc a ~ (lilT~(Ilsiollal stru(tlll( i)~
placing srveral elemcrlts side by sidc.
Figur( 2 SllOWS a mast having a trianglllar basc, tl-lc b(3sc com~ isirlg threc booms M and ~i'. This mast is, o~ COUlSC, not limited to a trial,glllar-based structure. It is possible to crea~c, frorrl tl-l( "basi~: planc concept", a threc-dimcnsional struct-lre having a bas( Wit3l "n" sidcs, lor c~alnpl(, triangular, squarr, rcctallgular, pentagonal, or hc~agoll,ll.
_ 5 _ i~'797fi~
The base oi the mast does not necessarily have to be regular and this is contrary to the state of the art, which represents a eonsiderable additional advantage.
The stability of tlle mast may be improved by rotation of the axes of the hinges. In faet, instead of being perpendicular to the plane of the sheet as shown in Figures la - lc, the axes of the hinges [lll, H~
"2 "2 ~2 1 rnay bc inelined by a predetcrrnined ang]e with r spect to thc perpendicular.
It is not necessary either for all the rotational axes of the hinges to be inelined by the same angle; only the axes of the same rod and those between two consecutive booms must be inelined by the same angle (for example, Hl, H~ 2 2 2 Figures 3a and 3b illustrate this variation. In Figure 3a, the rotational axis of hinges [H1, Hl , Hl ] is perpendieular to the plane of the sheet, whereas the rotational axis of hinges [H2, H2 , H2 ] is in the plane of this sheet. Figure 3b shows a perspective view thereof, the arrows indicating the possible rotations. This eonstruetion is elearly more stable than that shown in Figure l. In fact, let us consider the application of a force F acting at the level of point C.
The force F will be to a great extent absorbed by the rods carry-ing hinges ll~, 112 , '~2 This absorption i.s duc' to t]l( fact tllat tl-l`
force is in the direction oi thc rotatio11al axis oi Lh llillC,e.',. Tl)C 'itl-U~-ture would then undergo 110 appreciah]c l Lorrrlation. Tll impl-lv rr,(nt ~h~lL
obtained is all thc great i5 the sets r,r hill,c~cs of c.lch rod arc in 1incl by a diff~rent angel to tl-l perper)cliclllar to th plan o5 Lh( facc~ ~no~ll( r advantage is the rase of storage. ln factc, t.}lC' rods ar n0 10ngcr in ~n( same plane as the booms, which rcsults in a r~duction in th numl)cr c~
elements stackel on each othcr.
It is also clear that, by introduciTlg an inclinaLiorl Or thc rotational axis oi the hing-s, the structure no longer prcs nts a ~re5rr-ential axis of collapse.
-~. 1 7~37~'~
Storagc may bc faciliLated by using a mrmory system, for example, a flat spring (not ShVWIl~ mounted to the fastenings of the cables. Such a system allows folding internally within the base and avoids any inter-ference with the hinging or the deployment system. Thus, in the stored position, the cables are entirely trapped within the base.
The rvds bctween two consecutivl booms should have a length Less t-han twicr thc small side of thc base, so as to rc~duec to a minimuM the spacc takcn up.
ln thc case whcrc thc rnast is exposed to a unidireetional flow gcnerating a heat gralirnt, leflection of the mast is to be fcarcd. Such problems may bc minimi~ed by s]ightly twisting thc mast. For that it is sufficient for the stops [B1, B1 , B1 ; B2, B2 , B2 ] to be unsymmetrical and, for the cables [C , C~ between two eonsceutive booms LM, M~ ] to have different ~engths. The twisting direction may, if necessary, be reversed at regular intervals.
Figure 4 shows the extraction and deployment mechanism associated with the mast of an aspect of the invention. This mechanism is formed by sets of cams fixed to a first ring 8. This ring 8 is actuated by onc or more motors 9. Each set of cams is formed of two cams 10 and 11. Thcre are as many sets of cams as the base has sides (for example, three sets of cams in the case of the triangular-based structure shown by way of non-limiting example in Figurt 2).
Sevcral scrcws 12, threc for cxarnplc, arc prcvidc(l for actJ.Iting a base plate 13 which s~lpports the stor(d palt o~ mast so as to h( al)lc to levrl the storr part of thc rnast. Th( scr(ws 12 al-c dl-ivrn by m(alls o~ a second ring 14. This second ring has tcc:tll only on crtairl parts of its periphery so that the scrcws 12 arc ()oly actuatcd duril~ tllc intervals wl)cn cams ~0, ~1 arr not engcl&cd with the clc~nlcnts to bc dcploycd. I)uring Llle actions of cams 10. il, a system of fingcrs rctains thc non-dcployrcl pclC-kagc, thcse fingcrs bcing retract"ble and activatcd by the Lirst ring 8.
Fis~urLs 5a LO ad illustrate thL operation of the deploymLnt sys-tem. A lirst cam lO, bearing on a first projection specially provided for this purpose at the l(vel of the booms, allows a irst deployment of rods [L, 1,'~ etc. The height of this first deployment is practically equal to half the ]ength oI a girder. ~fter reaching this first position, a second cam 11, bearing on a secc)nd projection provided this time at the level of tht midc~le hinge (111, 112) of thc rods, allows total deployment of the rod.
The inLcrference bet~een thc second cam 1] and the movemcnt of the middle axis of the rod at the moment of locking in the deployed position (slight ~ithdrawal movement passing from the position of Figure Ib to that of Figure 1c) is limited, on the one hand, by the shape of the second cam and, on the other hand, by the natural novements of the hinges (linear) and the movements of the cams (circular).
The folding of the mast takes place by simple reversal of the rotation of the motors.
The advantages of the deployment mechanism according to aspect of the present invention with respect to the- state of the art are essentially the follo~ing:
The height of the cams is equal to half thc Iength between two booms. The cam is thus, less than half the size of thc- cam used in the case of the mast described in the above-iderltified United States l'atent No. 3,486,279;
'I'he irictiorl is very low~ ~incc~ thc actions al-e carric(l Ollt directly at tl~c 1CVel of the hirl$,cs wlli]c raicill$, ~h( s~ ct~lr(.
'I`he result is a stl--lctur.llly ligllt ~;ystc~
The present inventiorl relates to an unfo]dable and foldable mast of grrat rigidity and great length intended more especially, but in no limiting srnse, to be used in the spacr field, or on light vehieles for erecting telecomrnunications antennar, ete.
In thc! spaee field, the requirements of missions have only been concernrd up to now with masts having either great rigility and small ]ength or great length and ]ow rigidity. Except for a few rare exceptions, rep-reserlted more especial]y by the arms of automatic ]unar vellicles, no con-dition for folding masts has been requirrd up to the present. Aeeordingly, meehanisms of rlldim-ntary d~sign, e.g., pantographs and others, have been used.
Future missions will use high power generations formed from solar panels. In order to be able to use sueh solar panels again, or possibly to repair them on the ground, these panels will have to be unfoldable and fold-able. These panels will be deployed and folded by means of an unfoldable and foldable mast. The large area of the panels involves using masts of great length, oE great rigidity and having a small eneased volume. These new requirements eonsequently demend new concepts.
Although the deseription of the present invention in its various aspects relates prineipally to spaee app]icatinns, this latter is however not limited to these app]ications. The present applieatiorl in its varinls aspeets eould, for example, also b usrl ~or othcr app]icationC.~ ~.g., m.l ts transportable on ]ight vrlli les f)r er(ctin& I ]~comrrlullicati()lls alt n~ e having heights rangirg from a few m~tcrs to s vera] lens ol m l rs.
Unio]dab]e and follable mas~s have b~cn pror)os d in Ihc prior arl, particularly in United States Patent ~o. 3,486,279 issued to James 1. Webb.
These masts, whieh may be rapidly urlfo]dc(l from a fo]decl eondition o~ small volume, eompris( a plurality of inclividually oldable triangular seetion segments, formed by booms whieh are eonneeted together in two and whieh eomprises three longitudinal reetangular faces 1) ld tog Lher by two eables fixed diagonally at opposite corners of the rectallglc, by m ans of springs.
37~
The reetilnglllar sul-faecs of these sc~gments are pivotally eonneetrd together by means of flex;ble gireers, whieh form sides of the reetangles whieh are eurved into eireles when the strueturc is folded and whieh tend to straighten 50 as to assurnt a reetilinrar position when the mast is l~nfolded. Ilowevcr, the unfoldable and foldable masts cleseribed in this patent prescn~, a number of drawbaeks; th(y requirr- a high eonsurnption of energy bceaus( Or the eon-siderablc frietion induec(] in tl-e unfo]ding mcehanisrn, whieh energy must, in gcneral, be supp]i(d by batteries or other generators of thc same type;
a system of great preeision whierl opposcs roLation rnust bc providrd in thr ease of an applieation of the solar generators of tl-e same type; a systrm of great preeision whieh opposes rotation must be provided in the easr of an applieation of the solar generator type; and, they are not very flexible, do not allow variations and eonsequently limit any possibility of optimization.
Objeets of aspeets of the present invention inelude the provision of an unfoldable and foldab~e mast, having a light strueture but nevertheless great rigidity, in whieh the frietion indueed by the deployment operations is very small, whose stability is very high beeause the stresses are dis-tributed along the three axes and whose ease nf storage is improvrd wirh respeet to the prior art struetures by redueing the spaee required by redue-tion of the number of elements staeked on c~aeh othcr.
Thc present invention, in one aspeet, prnvi(l(s an unfollable and foldable mast eonsisting cssertially of a plural-ity ni elel~ tary parts, eaeh of whieh eomprises: a first hilS(' wi~h llnll si(l('':~ CilCIl siCl(' CnrrlF)ri'.ill&
a boom, eommclrl to a preeeding (I(nl(n~ar~ p-,r~; a s(eond IJI;( w-ith n sidcc.
eaeh side eornprising il boom, eornln~l- to a fo] ~ r~ r l( mr ntal y p~ w(~
eonseeutive sides of th- firsL base and the s(enl1cl base sllb~ell(lirlg al) allglc therebctween, a number of rods eonl-l eting togcther ih( angles or th( bascs, the numbcr of r-nds being ecl-lal to the number lf sid s o~ the bascs, the rods ineluding, in thc middlc-, and at thc cnds thcrcof, hil-lgrs haVil1g a dCgr('C
of frecdom, thereby making the rods bendable, th( hing(s eluil-l) d ~ith slopS;
eables forming eross-braees; and a deplnylrlcnt mechan-isrll.
1 ~797t~
By one variallt thereof, the first and second bases have any sym-metrical or unsymmetrical shape, e.g. a triangle, a square, a rectangle, a pentagon, or a hexagon.
By another variant, the rotational axes of the hinges are in di-ferent planes and are inclined by a predetermined angle.
By still another variant, the rotational axrs of thr hinges arr inclinc!d at different angles.
By still another variant, the rotational axes of the hinges of th same girder, betwcen two consecutivc elcmcrltary structures, are inclincd by the same anglc.
~y anotl~er variant, the eables are fixed to the opposite eorners of an elementary structurr by means of memory systems, e.g., by means of flat springs.
By yet a further variant, the rods between two consecutive elemcn-tary structures have a length less than twiee the smallest side of the base, thereby to reduce to a minimum the space required by the mast during storage.
By a still further variant, the hinges are provided with unsymmet-rical stops, thereby making the mast slightly twisted out including cablcs of different lengths placed, thereby between two consecutive booms to mini-mi~e to the maximums as possible deflection of the mast, due particularly to a heat gradient generated by a unidir ctional flow applied to tlle mast.
By a further variant, the cleplo~ment rncchanism comprises sets of cams fixed to a first toothed rirlg, actuat cJ by on -r mol-~ motors.
By a variatiorl thcreof, each se~ o~ cams is rorrrl~d Or ~W(! (~.lmS.
By a further variaLiorl thereof, th nLInlb(!r ol set, of cams is Iqu.
to thr numbrr of sid s which compris thc base.
By yet allotl-lcl- variation thereof, a scconl ring is associatc(l Witl thc driving SCI'CWS of thc firs~ ring, the dri~ing s rews l- ing intcgr31 with a base plate which supports the stored mast, so as to prcvidc gr3lual lcveling of the sLor d part of th mast, ~l~c econd ring carrying tc th or-lly at ccrtain parts of its periphcry so that thr scrcws are only actuate(l by 37~
thc ring during the intervals during which the cams of the sets of cams are not cngagcd witl the e]ements of the stored mast to be deployed.
By a still further variation thercof, the mast includes a system of retractable fingers actuated by the first ring, for retaining non-deployed stored part of the mast on the base plate during the drployment action of the cams.
By a further variant, the mast includes a first projection carried by the base, ovrr which a first cam of the correspondir)g set of cams, movcs, to causc a Sirst dcp]oymcnt of the rod.
By a still furthc!r variant, cach of the mildle hinges of the rocls carries a seconl projection ovcr which the second cam of thc corresponding set of cams move, so as to cause complete deployment of the rod.
By yet a further variant, the first ring also carries folding cams staggered with respect to the sets o~ cams for progressive extraction of the structure of the mast.
In the accompanying drawings, `
Figure 1 shows schematically the successivr phases of deploying a mast in accordance with an aspect of the present invention (Figures la tO
1 c ) ;
Figure 2 shows an example of a mast structure in accordance with an aspcct of the invention, with a triangular basc;
Figure 3 shows schematically mbodimcnts of thc hingcs in wll-icl, thc rotational axcs of thesc latter arc incline(l by a cre(lct(rr~ ecl arlgl with rcspcct to the pcrpen(licular, ~he slop( I) -ing abl( lo b( dil~(rellt depcnding on tll( hinges consil(red (l:igulrs 3a - 3b~;
Figul- 4 is a sch lnatic represelltation of a rrlecl-lallic;rrl lor dcployin,c~
the mast in accc-r(lance with an as~.ccL of tl-le prescnt invention; and Fig7ure 5 illustrates (Figurcs 5a to 5cl) th( mode of operation.
The mast, which forms the subjcct of an aspcct of th(~ prescnt in-vention, is ormccl of rods [L, L ], bc)oms ~, M ] and cross-bra(cs, [e.g.
cablcs C, C~].
11'~.~37~,~
The principlc of the foldable mast will be described hereinafter with reference to Figures la to lc. These Figures represent the different phases of deployment oi a bidimensional mast. This mast comprises two booms [M', M], two cables [C', C~ and two rods [L', L] which are made bendable in the middle and at the cnds thcreof by means of hinges [respectively H1~ H2;
H1', 3l2'; and H1", ll2"].
Figur( la sllows the beginning of thc dcploymcnt. The rods [L', L]
are rnoved contirluously in thc direction of tllc arrows, by rncans of a dcploy-ment mechanisim, not showr~ in this Figllre. I)uring dcployrncTlt, the cab]cs [C', C~ gradually stretch. Figure lb shows a position in W3~iC]l thL cablcs [C', C~ are quite strrtched; the final position, however, has not yet been reached. The movement of the rods [L', L~ continuts further, which causes elastic deformation of the cables [C', C]. This deformation is maximum when the two parts of the rods [L', L] form a straight line. Further movemcnt of the rods [L', 1,] slightly slackens the cables [C', C]. The final postion is reached when further movement is made possible by stops [B1, B1', Bl";
and B2 B2~ B2"] integrally formed with the hinges [H1~ H2: H1', H2'; and H1", H2"] (ser Figure lc). Ihe position 03 the stops ~B1, B1', B1"j and B2, B2', B2"~ is chosen so that a stress rcmains in the cables [C',C].
The stability of thc structure thus obtained is total. ln fact, thc outward rnovemerlt of the rods Ll, L'] is madc virtlla]ly impossiblc by thr prescnce of thr StOpS ~B~, Bl', P,l"; B2, E2', B2"] ancl inwrlrrlrllov~rn~n~
is madc diffi~ult by thc prcslrcss((l cal)lcs [C', (¦.
From t}-le "basic plan( conccr)t" ol îhe mast, c.g.~ a~ SbO~!II ir, ligures la to 1c, it is possit)lc to crcatc a ~ (lilT~(Ilsiollal stru(tlll( i)~
placing srveral elemcrlts side by sidc.
Figur( 2 SllOWS a mast having a trianglllar basc, tl-lc b(3sc com~ isirlg threc booms M and ~i'. This mast is, o~ COUlSC, not limited to a trial,glllar-based structure. It is possible to crea~c, frorrl tl-l( "basi~: planc concept", a threc-dimcnsional struct-lre having a bas( Wit3l "n" sidcs, lor c~alnpl(, triangular, squarr, rcctallgular, pentagonal, or hc~agoll,ll.
_ 5 _ i~'797fi~
The base oi the mast does not necessarily have to be regular and this is contrary to the state of the art, which represents a eonsiderable additional advantage.
The stability of tlle mast may be improved by rotation of the axes of the hinges. In faet, instead of being perpendicular to the plane of the sheet as shown in Figures la - lc, the axes of the hinges [lll, H~
"2 "2 ~2 1 rnay bc inelined by a predetcrrnined ang]e with r spect to thc perpendicular.
It is not necessary either for all the rotational axes of the hinges to be inelined by the same angle; only the axes of the same rod and those between two consecutive booms must be inelined by the same angle (for example, Hl, H~ 2 2 2 Figures 3a and 3b illustrate this variation. In Figure 3a, the rotational axis of hinges [H1, Hl , Hl ] is perpendieular to the plane of the sheet, whereas the rotational axis of hinges [H2, H2 , H2 ] is in the plane of this sheet. Figure 3b shows a perspective view thereof, the arrows indicating the possible rotations. This eonstruetion is elearly more stable than that shown in Figure l. In fact, let us consider the application of a force F acting at the level of point C.
The force F will be to a great extent absorbed by the rods carry-ing hinges ll~, 112 , '~2 This absorption i.s duc' to t]l( fact tllat tl-l`
force is in the direction oi thc rotatio11al axis oi Lh llillC,e.',. Tl)C 'itl-U~-ture would then undergo 110 appreciah]c l Lorrrlation. Tll impl-lv rr,(nt ~h~lL
obtained is all thc great i5 the sets r,r hill,c~cs of c.lch rod arc in 1incl by a diff~rent angel to tl-l perper)cliclllar to th plan o5 Lh( facc~ ~no~ll( r advantage is the rase of storage. ln factc, t.}lC' rods ar n0 10ngcr in ~n( same plane as the booms, which rcsults in a r~duction in th numl)cr c~
elements stackel on each othcr.
It is also clear that, by introduciTlg an inclinaLiorl Or thc rotational axis oi the hing-s, the structure no longer prcs nts a ~re5rr-ential axis of collapse.
-~. 1 7~37~'~
Storagc may bc faciliLated by using a mrmory system, for example, a flat spring (not ShVWIl~ mounted to the fastenings of the cables. Such a system allows folding internally within the base and avoids any inter-ference with the hinging or the deployment system. Thus, in the stored position, the cables are entirely trapped within the base.
The rvds bctween two consecutivl booms should have a length Less t-han twicr thc small side of thc base, so as to rc~duec to a minimuM the spacc takcn up.
ln thc case whcrc thc rnast is exposed to a unidireetional flow gcnerating a heat gralirnt, leflection of the mast is to be fcarcd. Such problems may bc minimi~ed by s]ightly twisting thc mast. For that it is sufficient for the stops [B1, B1 , B1 ; B2, B2 , B2 ] to be unsymmetrical and, for the cables [C , C~ between two eonsceutive booms LM, M~ ] to have different ~engths. The twisting direction may, if necessary, be reversed at regular intervals.
Figure 4 shows the extraction and deployment mechanism associated with the mast of an aspect of the invention. This mechanism is formed by sets of cams fixed to a first ring 8. This ring 8 is actuated by onc or more motors 9. Each set of cams is formed of two cams 10 and 11. Thcre are as many sets of cams as the base has sides (for example, three sets of cams in the case of the triangular-based structure shown by way of non-limiting example in Figurt 2).
Sevcral scrcws 12, threc for cxarnplc, arc prcvidc(l for actJ.Iting a base plate 13 which s~lpports the stor(d palt o~ mast so as to h( al)lc to levrl the storr part of thc rnast. Th( scr(ws 12 al-c dl-ivrn by m(alls o~ a second ring 14. This second ring has tcc:tll only on crtairl parts of its periphery so that the scrcws 12 arc ()oly actuatcd duril~ tllc intervals wl)cn cams ~0, ~1 arr not engcl&cd with the clc~nlcnts to bc dcploycd. I)uring Llle actions of cams 10. il, a system of fingcrs rctains thc non-dcployrcl pclC-kagc, thcse fingcrs bcing retract"ble and activatcd by the Lirst ring 8.
Fis~urLs 5a LO ad illustrate thL operation of the deploymLnt sys-tem. A lirst cam lO, bearing on a first projection specially provided for this purpose at the l(vel of the booms, allows a irst deployment of rods [L, 1,'~ etc. The height of this first deployment is practically equal to half the ]ength oI a girder. ~fter reaching this first position, a second cam 11, bearing on a secc)nd projection provided this time at the level of tht midc~le hinge (111, 112) of thc rods, allows total deployment of the rod.
The inLcrference bet~een thc second cam 1] and the movemcnt of the middle axis of the rod at the moment of locking in the deployed position (slight ~ithdrawal movement passing from the position of Figure Ib to that of Figure 1c) is limited, on the one hand, by the shape of the second cam and, on the other hand, by the natural novements of the hinges (linear) and the movements of the cams (circular).
The folding of the mast takes place by simple reversal of the rotation of the motors.
The advantages of the deployment mechanism according to aspect of the present invention with respect to the- state of the art are essentially the follo~ing:
The height of the cams is equal to half thc Iength between two booms. The cam is thus, less than half the size of thc- cam used in the case of the mast described in the above-iderltified United States l'atent No. 3,486,279;
'I'he irictiorl is very low~ ~incc~ thc actions al-e carric(l Ollt directly at tl~c 1CVel of the hirl$,cs wlli]c raicill$, ~h( s~ ct~lr(.
'I`he result is a stl--lctur.llly ligllt ~;ystc~
Claims (18)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An unfoldable and foldable mast consisting essentially of a plurality of elementary parts, each of which comprises: a first base with n sides, each side comprising a boom, common to a preceding elementary part; a second base with n sides, each side comprising a boom, common to a following elementary part; two consecutive sides of said first base and said second base subtending an angle therebetween, a number of rods connecting together said angles or said bases, the number of rods being equal to the number of sides of said bases, said rods including, in the middle, and at the ends thereof, hinges having a degree of freedom, thereby making said rods bendable, said hinges being equipped with stops; cables forming cross-braces; and a deployment mechanism.
2. Unfoldable and foldable mast as claimed in claim 1, wherein said first and second bases have a symmetrical or an unsymmetrical shape.
3. The unfoldable and foldable mast of claim 2 wherein said shape is selected from a triangle, a square, a rectangle, a pentagon or a hexagon.
4. Unfoldable and foldable mast as claimed in claim 1 wherein the rotational axes of said hinges are in different planes and are inclined by a predetermined angle.
5. Unfoldable and foldable mast as claimed in claim 4, wherein the rotational axes of said hinges are inclined at different angles.
6. Unfoldable and foldable mast as claimed in claim 4, wherein the rotational axes of said hinges of the same girder, between two consecutive elementary structures, are inclined by the same angle.
7. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said cables are fixed to the opposite corners of an elementary struc-ture by means of memory systems.
8. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said cables are fixed to the opposite corners of an elementary struc-ture by means of flat springs.
9. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said rods between two consecutive elementary structures have a length less than twice the smallest side of the base, thereby to reduce to a minimum the space required by the mast during storage.
10. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said hinges are provided with unsymmetrical stops, thereby making said mast slightly twisted and including cables of different lengths placed, thereby two consecutive booms to minimize to the maximum as possible deflection of the mast, due particularly to a heat gradient generated by a unidirectional flow applied to said mast.
11. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said deployment mechanism comprises sets of cams fixed to a first toothed ring, actuated by one or more motors.
12. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said deployment mechanism comprises sets of cams fixed to a first toothed ring, actuated by one or more motors and wherein each set of cams is formed of two cams.
13. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said deployment mechanism comprises sets of cams fixed to a first toothed ring, actuated by one or more motors, and wherein the number of sets of cams is equal to the number of sides comprising the base.
14. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said deployment mechanism comprises sets of cams fixed to a first toothed ring, actuated by one or more motors, and including a second ring associated with driving screws of said first ring, said driving screws being integral with a base plate which supports the stored mast, so as to provide gradual leveling of the stored part of the mast, said second ring carrying teeth only at certain part of its periphery so that said screws are only actuated by said ring during the intervals during which the cams of said sets of cams are not engaged with the elements of the stored mast to be deployed.
15. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said deployment mechanism comprises sets of cams fixed to a first toothed ring, actuated by one or more motors, including a system of retract-able fingers actuated by said first ring, for retaining non-deployed stored part of said mast on said base plate during the deployment action of said cams.
16. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, including a first projection carried by said base, over which a first cam of the corresponding set of cams, moves, to cause a first deployment of said rod.
17. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein each of the middle hinges of said rods carries a second projection over which the second cam of the corresponding set of cams, moves, so as to cause complete deployment of said rod.
18. Unfoldable and foldable mast as claimed in claims 1, 2 or 4, wherein said deployment mechanism comprises sets of cams fixed to a first toothed ring, actuated by one or more motors and wherein said first ring also carries folding cams staggered with respect to said sets of cams for progressive extraction of the structure of the mast.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8015937 | 1980-07-18 | ||
| FR8015937A FR2487133A1 (en) | 1980-07-18 | 1980-07-18 | Foldable mast for automatic lunar vehicle - has vertically opposing frames interconnected by hinged struts which are tensioned in unfolded attitude by cables |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1179768A true CA1179768A (en) | 1984-12-18 |
Family
ID=9244307
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000381566A Expired CA1179768A (en) | 1980-07-18 | 1981-07-10 | Unfoldable and foldable mast |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5799005A (en) |
| CA (1) | CA1179768A (en) |
| FR (1) | FR2487133A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3222475A1 (en) * | 1981-06-19 | 1983-01-27 | British Aerospace Public Ltd. Co., London | EXTENDABLE MASTER STRUCTURE |
| US4578919A (en) * | 1982-07-14 | 1986-04-01 | Harris Corporation | Self-stowing arrangement for structural tension members with taper latch hinge coupling joints |
| US4569176A (en) * | 1983-11-28 | 1986-02-11 | Astro Research Corporation | Rigid diagonal deployable lattice column |
| CA1310165C (en) * | 1987-04-24 | 1992-11-17 | Louis R. Adams | Collapsible truss structure |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4015653A (en) * | 1976-04-08 | 1977-04-05 | General Dynamics Corporation | Panel deployment system |
-
1980
- 1980-07-18 FR FR8015937A patent/FR2487133A1/en active Granted
-
1981
- 1981-07-10 CA CA000381566A patent/CA1179768A/en not_active Expired
- 1981-07-17 JP JP56112883A patent/JPS5799005A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2487133B1 (en) | 1982-09-24 |
| JPS6349924B2 (en) | 1988-10-06 |
| JPS5799005A (en) | 1982-06-19 |
| FR2487133A1 (en) | 1982-01-22 |
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| MKEX | Expiry |