[0001] There is already known from US-A-2 946 556 a segmented extendible boom having longitudinal
inner and outer ends and having a plurality of hingedly connected segments, a mechanism
for extending the segments for forming the boom and for retracting the segments into
a coil onto a storage reel, said storage reel being located during retraction and
extension of the segments generally adjacent the longitudinal inner end of the boom,
and further comprising means for supporting the extended segments for carrying a vertical
load thereon.
[0002] The above mentioned extendible boom according to US-A-2 946 556 is primarily designed
for pushing or pulling objects rather than operating as a boom. It would be used,
for example, to move scenery on a stage. The boom segments of this conventional device
are supported by wheels which ride along a floor. These segments do not stow in a
nested relationship, but rather are wrapped helically. This arrangement results in
less compact stowage, which is particularly undesirable for a mobile object such as
a boom. As the segments of this conventional device are extended away from a helical
reeling mechanism, they form an arm which does not extend perpendicularly from the
reeling mechanism. As the arm extends further and further, any attempts to use this
type of arrangement as a boom will result in the creation of twisting movements.
[0003] From DE-B-11 1 99 461 an extendible boom is known with segments comprising a V-shaped
cross-section. This conventional boom becomes rigid only by locking two boom sections
(top and bottom) together. As a result, two independent reeling mechanisms are required.
The result is that twice the weight is required for both the reeling mechanisms and
the boom.
[0004] The invention as claimed is intended to remedy the drawbacks of the most pertinent
prior art (US-A-2,946,556). It solves the problem of how to design an extendible,
segmented boom which allows a compact storage of the segments. Furthermore, it is
aimed to provide segments for the extendible boom structure which resists overloads
and which are able to carry remarkably high boom loads. Furthermore, the invention
aims to provide an extendible boom structure which resists twisting and racking and
has high strength against lateral loads.
[0005] In accordance with the invention, the above technical problem is solved by the subject
matter of claim 1.
[0006] The advantages offered by the invention are mainly that the segments of the present
invention stow in a nested relationship and that the elastic hinges allow these segments
to nest inside one another even if there is some obstructions such as dirt or the
like between the nesting segment and the segment therebelow. Preferred embodiments
and further improvements of the subject matter of claim 1 are comprised within the
sub-claims.
[0007] The extendible boom structure of the invention comprises boom segments of uniform
cross-sections with the longitudinal lengths of adjacent segments being progressively
smaller thereby making the boom relatively lightweight at its outer end and requiring
less support. The boom is strengthened by means of pre-stress cables which integrally
pass through laterally extending flanges on each segment in order to provide strength
to the boom for vertical loads. The placement of the pre-tension cables within the
laterally located flanges also provides resistance to side forces on the boom. A set
of auxiliary cables may be used to prevent the pivotally coupled segments from pivoting
away from each other when the boom is turned up- sidedown, providing an important
safety feature for the boom.
[0008] The progressively smaller longitudinal pair length and the hollow configuration of
the segments permit a boom to be compactly stored in a magazine. The boom segments
are pivotally connected for movement about transverse axes. The V-shaped segments
terminate at the wide ends in laterally extending flanges which contain the prestressed
flexible cables which are integrally connected to each of the flanges and are located
at the outer extremities of the segments. The cables support vertical loads on the
boom. Because of their spacing at the outer extremity of the segments, the cables
also resist side loading on the boom.
[0009] The boom segments when coiled nest within each other to form a generally square configuration
with the progessively smaller boom segments located near the center of the configuration.
The boom coiling structure has a central axle about which the segments are coiled.
The coil is automatically lowered and raised as the segments are uncoiled or coiled,
respectively, to provide an optimum angle of insertion or retraction of the boom segments.
As the boom segments are dispensed from the storage magazine, a spring is wound up
to provide a return force for retracting the boom segments into the magazine. The
interconnected, extendible adjacent boom segments wedge together at their sides so
as to resist relative side and longitudinal twisting movement of the segments. An
auxiliary cable can be provided for supporting the boom segments when the boom is
turned upside down. This cable prevents the pivotal movement of the segments. Clips
are provided within the hollow portion of the segments for carrying power cables and
the like to the end of the boom. The power cables are automatically fed into the clips
as the boom is extended. The boom extension and retraction apparatus is constructed
so that it can be varied in elevation by positioning the boom in a vertical direction
in contact with the support underlying the entire structure. The boom can then be
extended or retracted to fix the elevation of the entire structure with respect to
the underlying support base. The boom is then locked into vertical position.
[0010] One way of carrying out the invention is described in detail below with reference
to drawings which illustrate only one specific embodiment, in which:
Fig. 1 is a partially cut-away side elevation view of as assembled segmented extendible
boom apparatus with the boom segments in a coiled, restricted arrangement;
Fig. 2 is a front elevation view of a segmented extendible boom assembly;
Fig. 3 is a partially cut-away side view of the first and second outermost boom segments
with the drive sprocket gear engaging the second boom segment;
Fig. 4 is a top, partially cut-away view of the forward portion of the upper roller
part of the boom retraction apparatus shown engaging the top surfaces of a boom segment;
Fig. 5 is a view of the bottom rollers of the boom retraction apparatus shown contacting
the lower surfaces of a boom segment;
Fig. 6 is a partially exploded cross-sectional view of a boom segment shown engaging
the support rollers of the retraction apparatus;
Fig. 7 is a partially cut away sectional view of portions of two adjacent engaged
boom segments taken along section line 7-7 of Fig. 6;
Fig. 8 is a sectional view of the interlocking wedges of two adjacent boom segments
taken along section line 8-8 of Fig. 7;
Fig. 9 is a view showing two adjacent segments pivoted with respect to each other;
Fig. 10 is a sectional view of a boom segment and sprocket gear taken along sectional
line 10-10 of Fig. 3;
Fig. 11 is a diagrammatical representation of the boom elevation apparatus;
Fig. 12a is a side view of an auxiliary hose guide means; and
Fig. 12b is a front view of the auxiliary hose guide means.
Best Mode for Carrying Out the Invention
[0011] Referring to Fig. 1, a segmented extendible boom includes a plurality of boom segments
10 which are compactly stored in a storage assembly 12. The boom segments are extended
or retracted by means of a segment support and driver assembly 14, which in turn is
mounted to a fork-shaped support frame 16, also shown in Fig. 2. The frame 16 is rotated
with respect to a support post 18. The support post is fixed to a support base. The
apparatus shown provides means for extending and positioning a boom formed from a
plurality of segments 10. The boom has, for example, a hoist cable 20 positioned at
the end thereof for handling and hoisting of loads. The hoist cable 20 passes over
a hoist sheave 22. A conventional hoist motor and winch assembly 24 is shown as a
typical means of controlling the hoist cable 20.
Segment Support and Drive Assembly
[0012] The boom segment support and drive assembly 14 includes a frame formed from a pair
of side plates 30 which are maintained in a spaced-part relationship by means of a
plurality of cross-brace members 32 which are welded or otherwise suitably fastened
to the side plates to provide a rigid support frame. As shown in Figs. 1 and 2, the
support frame is pivotal about pins 34 which extend through appropriate apertures
at the ends of the extending arms 36 of the fork-shaped frame 16. Two hydraulic cylinders
38 are each pivotally connected at one end to the frame 16 and at the other end to
brackets projecting from the support and drive assembly 14 as shown. The cylinders
permit the angle of elevation of the boom to be adjusted to a desired setting. The
boom may be flipped all the way over to provide a low profile for storage or transportation.
[0013] The forked frame 16 pivots about a center pin 40 on bearings 42, 44 and is rotated
by means of a swing motor 46 which drives a pulley 48. A drive cable 50 driven by
the pulley 48 engages a groove 52 extending around the top portion of a base 54. Rollers
58 are mounted on tabs 60 which project from a support 55 fixed to a deck or the like
and the rollers guide the post 18. The height of the entire boom assembly is adjustable
and the base 54 is positioned at various points by means of a lock pin 62 which passes
through the support 55 and one of a plurality of vertically spaced apertures on the
post 18, which post is adapted to have additional extensions connected thereto.
The Boom Segments
[0014] The construction of a boom segment 10 is shown in cross-section in Fig. 6. Each of
the segments 10 has a uniform cross-sectional configuration and the segments differ
only in length. Fabrication of the segments is simplified by using standardized segments.
The strength of each segment is the same as the other segments, wherever located in
the boom. Each segment 10 is a truncated, V-shaped structure which includes a generally
flat bottom portion 70 with side walls 72 extending upwardly and at oblique angles
to the flat bottom portion 70. Extending longitudinally along the outside of the flat
bottom portion 70 is a pintle rail 74 having a generally hollow interior, as shown.
Holes 75, as shown in Fig. 7, are provided in the rail 74 at uniform spacings for
receiving pins, or pintles 76. The pintles 76 form a rack which is engaged by a gear
for driving the segments in a longitudinal direction. A pair of downwardly extending
flanges 78 are formed near the outside edge of each of the flat bottom plates 70 for
each segment. These flanges cooperate with the pintle rail to provide a pair of cable
troughs for a plurality of auxiliary cables 79. Laterally extending reinforcement
ribs 82 are provided along the bottom plate 70 near the longitudinal ends of each
segment 10. Welded in place near the top and at one end of each segment 10 is a rod,
or cross-member 80, to which are affixed clamps 82 for cables, hoses, and the like.
Each clamp 82 has two segments which spring together to hold, for example, an electrical
cable or a pneumatic hose providing power to operate the hoist motor or the like,
as required.
[0015] Figs. 3, 7 and 9 show some of the details for pivotal connection of adjacent segments.
The pivotal connection of the segments 10 is utilized primarily in storing the segments
and is accomplished by means of a pair of elastically extendible hinge straps 90,
as shown in Fig. 3. Because the heavy loading on the boom is carried by a series of
cables, the hinges are not necessarily required to be heavy duty. One end of each
of the straps 90 is riveted by means of a rivet 92 to the exterior wall of the segment,
as shown. An outwardly bowed spring portion 94 is provided on each strap 90 which
permits each strap 90 to be elastically lengthwise extended. Pins 96 engage elongated
slots 98 formed in the straps to permit elastic lengthwise extension of the straps.
Two straps are joined together by means of hinge pins 100 so that adjacent segments
10 are pivotal about the hinge pins 100 by as much as 90°, as shown in Fig. 9 of the
drawing. The elasticity of the hinge straps permits the abutting ends of the segments
10 to move slightly apart if an overload force is applied against the segments 10
to prevent damage to the segments and joints and to provide a safety factor when the
support cables are stretched by heavy loading.
[0016] Each of the boom segments 10 is guided and locked end-to-end in an abutting relationship
with adjacent segments. The segments are guided together by means of the angled plates
102, 104, shown in Figs. 7 and 8. Figs. 7 and 9 show an outwardly extending end portion
of the rod 80 engaged by a cam-slot 106 formed in a projecting end portion of each
segment 10. Fig. 9 shows a rod 80 positioned at the entrance of the cam-slot 106.
As the segments 10 are pivoted together, the rod 80 rides within the slot 106 and
guides the angle plates 102, 104 into an engaging relationship, as shown in Fig. 8.
When the angle plates are engaged, lateral movement of the adjacent segments is prevented.
[0017] Fig. 6 shows a cross-sectional end view of a boom segment 10 having a pair of oppositely
extending flanges 108 located at the wider end of each segment. Each flange has a
lower half 110 and an upper half 112. The flange lower half 110 is fixed to the exterior
wall of a segment. The halves 110, 112 of each flange contain corresponding countersunk
apertures for receiving fastening hardware, such as nuts and bolts or rivets 113.
Located at the outer extremities of the flange half are the hinge straps 90, previously
described. Each flange lower half 110 has a raised convex portion 114 and a grooved
concave portion 116 which extend the length of the flange. Similarly, each flange
upper half 112 has a grooved concave portion 118 and a raised convex portion 120.
The convex portions provide some additional strengthening to the flanges in areas
of greater stress under heavy loading. The raised and the grooved portions engage
oppositely formed portions of guide and support rollers described below.
[0018] Figs. 6 and 7 show a plurality of longitudinally extending ribs 130 formed in the
upper and lower halves 110, 112 of the flanges 108. A plurality of half-sleeve members
132 fit in the slots formed between the ribs 130. Each half-sleeve 132 engages and
clamps one side of one of a plurality of longitudinally extending stress cables 134
(typically shown). When the upper and lower halves 110, 112 of the flanges 108 are
assembled together with the half-sleeve 132, the main stress cables 134 are sandwiched
and held within the flanges 108. The main stress cables 134 extend the length of the
boom from segment to segment and are tensioned to support the boom. When the segments
are extended, the cables 134 are placed in tension and provide the main strength for
supporting vertical loads on the boom. The cables are not clamped adjacent the hinge
points to allow free flexing of the cable to minimize sharp angles and abrasion.
[0019] Fig. 4 shows a force vector F having a sideload force component on the boom. The
cut-away section of the boom segment shows the main stress cables 134. The sideload
force component creates a moment tending to laterally pivot the boom segments about
the side 153. The cables 134 provide forces opposing lateral pivoting. The cable furthest
from the side 153 has a moment arm L and the other cables also have smaller moment
arms. All of the cables with their corresponding moment arms provide moments opposing
lateral pivoting of the boom. Thus the wide transverse width of the flanges increases
the effective moment arms of the cables to advantageously withstand lateral loads.
These moments provided by the cables 134 are in addition to the forces provided by
the structural design of the segments alone.
Boom Support Means
[0020] Referring to Figs. 1 and 2, boom segments 10 are driven inwardly and outwardly from
the boom support means 14 by means of a main boom drive hydraulic motor 140 having
a drive sprocket gear 142 connected thereto. The drive sprocket gear 142 engages a
drive chain 144 which, in turn, engages a driven sprocket 146 which is affixed to
the main boom segment drive pinion gear 148, the teeth of which engage the pintles
76 forming the rack on the bottom of the boom segments 10. The boom segments are thus
moved inwardly and outwardly by a rack and pinion arrangement. The boom segments 10
are guided and supported within the boom support means 14 by a plurality of rollers.
Side rollers 160 contact the upwardly extending sides 72 of the segments 10, as shown
in Figs. 1 and 2.
[0021] Figs. 1, 2 and 6 show a plurality of rollers, each of which is spaced and aligned
for support of the boom segment flanges. All of the rollers described herein are appropriately
mounted using conventional bearings and mountings. Figs. 2 and 4 show the top inside
rollers 1 50 having convex external surfaces which mate with corresponding concave
surfaces 118 on the boom segment flanges. The top outside rollers 152 have concave
external surfaces which match the convex raised surfaces 120 formed on the flanges.
[0022] The lower surface of the flanges are engaged by a pair of large inside rollers 1
54 having a concave exterior surface which mates with the corresponding convex surface
114 of the flange and lower half 110 as shown in Figs 1, 2, 5, and 6. A pair of smaller
inside rollers 156 are aligned in the same line of direction as the rollers 154. A
pair of outside convex lower rollers 158 engage the concave portions 116 of the flange
lower half 110.
[0023] The rollers, as described above, provide support for the boom when it is extended
and serve as guides for extending and retracting the boom segments 10.
The Auxiliary Cable
[0024] Referring to Figs. 3 and 6, the auxiliary cables 79 are stored on a drum 170 which
is concentric with the main boom drive pinion gear 148. The cables are shown in Fig.
6. Fig. 3 shows the free ends of a cable 79 loops and fastened around the axle 172
of the drum 170 with cable fasteners 174. A cable 79 is fed through an aperture in
the grooved surface of the drum 170. A cable 79 is laid within the groove so that
one portion of the cable overlies the other portion. The cables 79 are payed out from
the grooves on the drums 170 into the longitudinally extending cable troughs along
the bottom of the segments. The cables extend out to the endmost section, as shown
in Fig. 3, and each cable passes around sheaves 176, 178. The sheaves 176 rotate about
an axle 180 which is supported by a bracket 182. The position of the bracket is adjusted
relative to the segment by means of an adjustment screw 184 which passes through the
end of the adjustment bracket 182, through a block 186 fastened to the segment 10
and into an adjustment nut 188. The longitudinal position of the bracket 182 is adjusted
to provide sufficient tension on the cables 79. The length of the wraps of cable 79
around the drum 170 is approximately equal to the boom segment lengths. Because the
inner cable wrap has a diameter slightly less than the diameter of the outer cable
wrap, the outer cable wrap is somewhat longer than the inner cable wrap and the sheave
176 permits the lengths to be equalized.
[0025] The purpose of the auxiliary cables 79 is to maintain the boom segments 10 in their
extended positions when the boom is turned over or when an upward force is exerted
against the boom. Without the cables 79, the boom segments 10 would pivot about their
pivot pins 100 and collapse the boom. The cables 79 thus serve as safety cables and
also permit the boom to be used in an inverted position. Fig. 10 of the drawing shows
a sectional view of a boom segment, the drum 170 and the drive pinion gear 148.
Auxiliary Reel Means
[0026] Figs. 1 and 2 show an auxiliary hose storage reel 190 mounted on a bracket 192. Hydraulic
swivel couplings 194 provide fluid connection between external hydraulic hoses (not
shown) and a hollow hose reel shaft 195. The hollow shaft 195 is connected to hydraulic
hoses 196 coiled on each of the reels 190. It is readily apparent that other auxiliary
hoses, cables and the like may be stored on the reels 190, as required. The cables,
hoses, or the like stored on said reels are used for a variety of auxiliary functions,
such as, for example, operating a hoist motor or winch at the end of the boom. Means
are provided for automatically feeding the hoses 196 into the clips 82 which extend
upwardly from the rods 80 on each of the boom segments 10. This means includes a pair
of feed wheels 200 rotatably positioned beneath the storage reels 190. Figs. 12A and
12B show a feed wheel 200 having a portion of a hose 196 contained within a groove
197 extending around the periphery of said wheel as shown. The spring clips 82 have
resilient, opposing side spring members 202 which are normally biased together to
hold a hose or the like therebetween. In Fig. 12B, the feed wheel 200 is shown to
have tapered edges 204 formed next to the circumferencial peripheral groove 197. The
tapered sides 204 of the feed wheel open the flexible arms of the clip 82 as it moves
past the feed wheel 200 and the hose 196 is placed between the arms. As the hose clip
82 moves away from the wheel 200, the resilient arms 202 spring together and hold
the hose 196 in position on a boom segment. When the boom is inverted, the clips 82
securely hold the hoses in position.
Segment Storage
[0027] Fig. 1 shows the segment storage means 12 having the interconnected boom segments
10 coiled in multiple wraps around a core 206. The segments 10 form a generally square
configuration around the core 206 and the core 206 rotates on an axis formed by an
axle 208. The ends of the cables 134 are fixed to the core 206.
[0028] The lengths of the segments 10 are chosen to have the segments compactly nest together.
As an example, the sides of the core are 20.3 cm in length. Each segment increases
the thickness of the configuration by 50.8 mm. The first segment on the core is 22.8
cm long. The second and third segments are 25.4 cm long. The fourth and fifth segments
are 31.2 cm long. This sequence is continued to provide the square configuration on
the core 206 as shown in Fig. 1.
[0029] The entire segment storage assembly 12 moves up and down along the storage assembly
support posts 210 as shown in Figs. 1, 2 and 11. The core support axle 208 extends
through a pair of slidable brackets 212, each of which is mounted for movement on
one of the support posts 210 by means of four rollers 214. Attached to each of the
posts 210 is a rack 216. Each rack 216 is engaged by a pinion gear 218 which is fixed
to a larger gear 220. The larger gears 220 are each driven by a chain 222. Each chain
is connected to a gear 224 on one end of the axle 208 as shown in Fig. 1. It should
be readily understood that as the segment core rotates with its axle 208, the rack
and gear arrangement will move the coiled up segments along the support posts 210.
Attached to each side of the core 206 is a sheave 226, each of which has a cable 228
wrapped around it. Each cable 228 is also wrapped around one of a pair of helically
grooved drums 230 which are mounted between the side plates 30 on an axle 232. A spring
motor 234 having a helically wound ribbon spring 236 tensions the cables 228. As each
boom segment 10 is removed from around the core 206, the core 206 rotates with its
axle 208 and moves along the support posts. As segments are removed from the core,
the axle 208 is lowered which permits the boom segments 10 to be longitudinally aligned
with the rollers in the boom support means 14. When the boom segments are being retracted
and coiled into the storage assembly 12, the axis of the core is moved upwardly by
means of the rack and gear arrangement.
[0030] The spring motor 234 provides a substantially constant force to tension the cable
228. As segments are removed from the core, the cables 228 are removed from the helically
grooved drums 230 and the radius of the grooves of the drum 230 increases to counteract
the increasing force provided by the spring motor 234. This provides a substantially
constant tension on the cables 228 to assist in recoiling the boom segments.
Boom Pullover
[0031] Fig. 1 shows that the entire boom assembly can be pivoted about the pins 34 so that
the entire assembly can be turned upside down, as indicated by the elements shown
in phantom. An overbalance spring 250 provides assistance in moving the assembly.
One end of the spring is fixed to the pin engaging one end of the hydraulic cylinder
38. The other end of the spring is moved horizontally by the slide and pivot mechanism
251 which slides along a rail 252. The entire boom assembly can be pivoted about the
pins 34 to any elevation angle desired by means of the hydraulic cylinders 38.
Self-Raising
[0032] The boom assembly can be raised and lowered along the main support post 18. This
is accomplished by lowering the end of the boom so that the longitudinal axis of the
boom is positioned in a generally vertical direction. The boom segments are then either
retracted or extended, causing entire assembly to be raised with respect to the support
55.
[0033] While a particular embodiment of the invention has been shown and described, it should
be understood that the invention is not limited thereto since many modifications may
be made. It is therefore contemplated to cover by the present application any and
all such modifications that fall within the scope of the basic underlying principles
disclosed and claimed herein.
1. A segmented extendible boom having a longitudinal inner and outer end and having
a plurality of hingedly connected segments (10), a mechanism (76, 140-148) for extending
the segments for forming the boom and for retracting the segments into a coil onto
a storage reel (12), said storage reel being located during retraction and extension
of the segments generally adjacent the longitudinal inner end of the boom, and means
for supporting the extended segments for carrying a vertical load thereon, characterised
by said segments (10) having outwardly open, channel-shaped cross-sections capable
of nesting within one another, said segments each being defined by flat sidewalls
(72) converging from outer, widely spaced ends to inner, closely spaced ends and joined
at the inner spaced ends by a horizontal end wall (70), said segments being hinged
together for nesting with the horizontal end walls and flat sidewalls of the segments
adjacent and confronting one another when nested on the reel, and said segments having
opposed abutment surfaces for supporting the segments in a cantilevered position when
extended, and by common flexible cables (134) connected to each said segment (10)
for resisting side loads on said boom and for supporting vertical loads on said boom.
2. The boom of claim 1, further characterised by laterally extending flanges (108)
connected to said outer ends of the sidewalls (72), said flexible cables (134) connected
to each of said flanges, and rollers (150-158) above and below the flanges and engaged
therewith for cantilevering the segments (10) in the extended position.
3. The boom of claim 1, further characterised by elastically extendible hinges (90-100,
134) connecting the segments (10) together.
4. The boom of one of claims 1-3, further characterised by an auxiliary cable (79)
adjacent the opposite inner ends of the sidewalls (72) for supporting the extended
segment (10) against pivotal movement about said hinges in the opposite direction
for operating the boom in an extended inverted position.
5. The boom of one of claims 1-4, further characterised by said reel (12) for storing
said retracted segments (10) including a rotatable reel axle (208), and means (216-224)
for adjusting the location of the axle relative to the centerline of the extended
boom for moving the central axle towards the extended boom centerline as said coil
of segments on said reel (12) gets smaller during extension of said segments.
1. Flèche extensible à segments présentant des extrémités longitudinales intérieure
et extérieure et comportant plusieurs segments (10) articulés entre eux, un mécanisme
(76, 140-148) destiné à déployer les segments pour former la flèche et à replier les
segments en un enroulement sur une bobine (12) de stockage, ladite bobine de stockage
étant placée, pendant le repli et le déploiement des segments, globalement adjacente
à l'extrémité longitudinale intérieure de la flèche, et des moyens étant destinés
à supporter les segments déployés pour porter une charge verticale qui leur est appliquée,
caractérisée en ce que lesdits segments (10) présentent des sections en profilés en
U ouverts vers l'extérieur, capables de se loger les unes dans les autres, lesdits
segments étant définis chacun par des parois latérales plates (72) convergeant à partir
d'extrémités extérieures, largement espacées, vers des extrémités intérieures étroitement
espacées, et reliées, aux extrémités intérieures espacées, par une paroi extrême horizontale
(70), lesdits segments étant articulés entre eux pour s'emboîter les uns dans les
autres, les parois extrêmes horizontales et les parois latérales plates des segments
étant adjacentes et disposées face à face lorsque les segments sont emboîtés sur la
bobine, et lesdits segments présentant des surfaces opposées de butée destinées à
supporter les segments dans une position de porte-à-faux lorsqu'ils sont déployés,
et par des câbles flexibles communs (134) reliés à chacun desdits segments (10) afin
de résister aux charges latérales appliquées à ladite flèche et de supporter les charges
verticales imposées à ladite flèche.
2. Flèche selon la revendication 1, caractérisée en outre par des ailes (108) s'étendant
latéralement, reliées auxdites extrémités extérieures des parois latérales (72), lesdits
câbles flexibles (134), reliés à chacune desdites ailes, et des galets (150-158) situés
au-dessus et au-dessous des ailes et en contact avec ces dernières pour porter en
porte-à-faux les segments (10) dans la position déployée.
3. Flèche selon la revendication 1, caractérisée en outre par des charnières extensibles
élastiquement (90-100, 134) reliant les segments (10) les uns aux autres.
4. Flèche selon l'une des revendications 1-3, caractérisée en outre par un câble auxiliaire
(79) adjacent aux extrémités intérieures opposées des parois latérales (72) pour supporter
le segment déployé (10) afin de l'empêcher de pivoter autour desdites charnières dans
la direction opposée pour faire fonctionner la flèche dans une position déployée inversée.
5. Flèche selon l'une des revendications 1-4, caractérisée en outre en ce que ladite
bobine (12) de stockage desdits segments repliés (10) comprend un arbre tournant (208)
de bobine, et des moyens (216-224) destinés à régler la position de l'arbre par rapport
à l'axe central de la flèche déployée, afin de déplacer l'arbre central vers l'axe
central de la flèche déployée lorsque ledit enroulement de segments sur ladite bobine
(12) devient plus petit pendant le déploiement desdits segments.
1. Segmentierter, ausziehbarer Balken mit in Längsrichtung inneren und äußeren Enden
und mit einer Vielzahl von gelenkig verbundenen Segmenten (10), einer Einrichtung
(76, 140-148) zum Ausziehen der Segmente zur Ausbildung des Balkens sowie zum Rückziehen
der Segmente zu einem Wickel auf einer Aufbewahrungsrolle (12), wobei die Aufbewahrungsrolle
während des Rückziehens und des Ausziehens der Segmente im wesentlichen im Bereich
des in Längsrichtung inneren Endes des Balkens angeordnet ist, und mit Einrichtungen
zum Abstützen der ausgezogenen Segmente zwecks Aufnehmen einer darauf wirkenden Vertikalkraft,
dadurch gekennzeichnet, daß die Segmente (10) nach außen offene, kanalförmige Querschnitte
aufweisen, welche imstande sind, sich ineinander zu verschränken, wobei die Segmente
jeweils von ebenen Seitenwandungen (72) definiert sind, welche von äußeren, weit voneinander
entfernten Enden zu inneren, dicht beieinander liegenden Enden konvergieren und an
den inneren beabstandeten Enden mittels einer horizontalen Endwandung (70) verbunden
sind, wobei die Segmente gelenkig miteinander verbunden sind, um sich mit den horizontalen
Endwandungen und ebenen Seitenwandungen der Nachbarsegmente zu verschränken und in
auf der Aufbewahrungsrolle verschränkten Stellung einander zu konfrontieren, wobei
die Segmente ferner einander gegegenüberliegende Stoßflächen zwecks Abstützens der
Segmente in einer auskragenden Position im ausgezogenen Zustand aufweisen, und durch
gemeinsame, flexible Kabel (134), die mit jedem der Segmente (10) verbunden sind,
um auf den Balken einwirkenden Seitenkräften zu widerstehen und um auf den Balken
einwirkende Vertikalkräfte aufzunehmen.
2. Balken nach Anspruch 1, ferner gekennzeichnet durch sich seitliche erstreckende
Flansche (108), welche mit den äußeren Enden der Seitenwandungen (72) verbunden sind,
wobei die flexiblen Kabel (134) mit jedem der Flansche verbunden sind, und durch oberhalb
sowie unterhalb der Flansche und damit in Eingriff stehende Rollen (150-158), zum
Auskragen der Segmente (10) in der ausgezogenen Position.
3. Balken nach Anspruch 1, ferner gekennzeichnet durch elastisch ausziehbare Gelenkscharniere
(90-100, 134), welche die Segmente (10) miteinander verbinden.
4. Balken nach einem der Ansprüche 1 bis 3, ferner gekennzeichnet durch ein Hilfskabel
(79) im Bereich der einander gegenüberliegenden, inneren Enden der Seitenwandungen
(72) zwecks Abstützung der ausgezogenen Segmente (10) gegen eine Verschwenkungsbewegung
um die Gelenkscharniere in der entgegengesetzten Richtung zur Betätigung des Balkens
in eine ausgezogene, umgekehrte Position.
5. Balken nach einem der Ansprüche 1 bis 4, ferner dadurch gekennzeichnet, daß die
Rolle (12) zum Aufbewahren der rückgezogenen Segmente (10) eine drehbare Rollenachse
(208) sowie Einrichtungen (216-224) zum Einstellen der Ortslage der Achse relativ
zur Mittellinie des ausgezogenen Balkens aufweist, um die Zentralachse in Richtung
auf die Mittellinie des ausgezogenen Balkens zu bewegen, wenn der Wickel aus Segmenten
auf der Rolle (12) während des Ausziehens der Segmente kleiner wird.