JPS6349924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a collapsible and deployable mast having a combination of great stiffness and great length, and more particularly as a lightweight spacecraft in space. This relates to a mast that can be folded and expanded, and is used to erect communication antennas.

The requirements for masts during the launch of this type of spacecraft into outer space have so far been satisfied by either a combination of high stiffness and low length, or high length and low stiffness.

With the exception of a few rare cases, represented by special cases such as autonomous lunar modules, no folding requirements have been required for masts to date.
Therefore, mechanisms of basic design, such as the pantograph type, have been used until now.

Future launch spacecraft will carry large-capacity generators formed by solar panels.

Such solar panels need to be reusable and foldable and unfoldable to allow on-ground repairs. and,
These panels are unfolded and folded by foldable and deployable masts. The large area occupied by such panels called for the use of masts of great length, stiffness, and accommodation in small cases, which required new thinking.

Although the description of the present invention is directed herein primarily to the space exploration context, this is in no way meant to imply that the invention itself is limited to space applications. It can be used in a variety of other applications, such as portable masts for erecting communications antennas from a few meters to tens of meters in height on lightweight spacecraft.

Foldable and deployable masts have already been proposed in the prior art, in particular in US Pat.
No. 3,486,279 discloses a mast that can be rapidly expanded from a folded state to a small volume, and has the following features: In other words, there are a plurality of long columnar nodes with a triangular cross section, each of which is foldable, and two booms (stretch rods) connected two by two to form three long rectangular surfaces. At opposite corners, the two cables are connected diagonally, or in a staggered manner, using the force of a spring to form a single piece. The rectangular faces of these columns are connected to each other by girders of pivots or other flexible structures, which form the sides of the rectangle, and when the whole structure is folded they curve into a circle and form a mast. When it is unfolded, it tends to stretch straight and assumes a straight posture. However, the collapsible and deployable mast disclosed in this prior art invention also has various weaknesses.

Firstly, the considerable friction generated in the deployment mechanism requires high energy consumption.
Of course, that energy must generally be provided by a battery or other similar power generating device. Secondly, when this applies to solar generators,
In order to resist rotation, an ultra-precise mechanism must be provided. Furthermore, and thirdly, the collapsible and deployable masts described above are not sufficiently flexible or pliable and cannot accommodate various changes, so their possibilities of satisfactory use are quite limited. It happens.

Therefore, the object of the present invention is to have a lightweight structure, yet have high rigidity or strength, have low friction during the deployment operation, and also have a structure that allows various stresses to be absorbed along the three axes. Foldable and unfoldable, which maintains high stability due to being dispersed, reduces the number of assembled parts, reduces the required space, and significantly improves storage compared to prior art structures. It is to provide a must.

The invention basically provides a foldable and deployable mast characterized in that it consists of: (a) having a plurality of base units suitable for being interconnected to form collapsible and deployable sections of the mast, each of the sections including at least one of the base units; Each of said foundation units includes at least two booms disposed in the direction of mast deployment, and (b) a pair of cable means diagonally interconnecting the ends of said booms; and (c) said booms. (d) hinge means provided at the center and each end of the rod members; and (e) an outer portion of each rod member. a stopper means provided on the hinge means for restricting movement of the rod member, and the hinge means has a degree of freedom that allows the rod member to be folded inwardly and unfolded outwardly. and each hinge means disposed at a respective end of the rod member is adapted to move over the first deployment cam means of the mast deployment means to cause partial deployment of the respective rod member. a first projection of the mast deployment means, each hinge means being centrally located on the rod member to move the rod member outwardly into a fully deployed position; A collapsible and deployable mast characterized in that it has a second projection adapted to move on two deployment cam means.

In order to better understand the present invention, examples will now be described with reference to the accompanying drawings. Of course, as will be readily understood, the drawings, together with the relevant portions of the description, are merely for the purpose of illustrating the subject matter of the invention and are not intended to limit the invention in any way.

The mast, which is the subject of the invention, has cross-braces such as girders: L, L', booms: M, M', and cables: C, C'. ; cross-tightening).

First, the principle of a foldable mast will be described with reference to FIGS. 1a to 1c. These three figures show various aspects or modes when the two-dimensional mast is deployed. This mast consists of two booms M,
M' and two cables C, C' and two girders L,
L′, and are provided with hinges H ₁ , H ₂ and H′ ₁ , H′ ₂ , H″ ₁ , H″ ₂ so that they can be bent at the middle and ends, respectively. .

Figure 1a shows the beginning of deployment. That is,
The beams L' and L are moved continuously in the direction of the arrow by an unfolding mechanism not shown in the figure. During this deployment, cables C, C' are gradually tightened and
It will tighten up to the state shown in the figure. The movement of the girder further progresses, causing elastic deformation of the cable. When the two parts of the girder become straight, the elastic deformation reaches its maximum point. If you move the cable further beyond that point, a slight slack will appear in the cable. Finally reaching the final position, the hinges H ₁ , H ₂ , H′ ₁ , H′ ₂ , H″ ₁ , H″ ₂
(see Figure 1c)
B ₁ , B′ ₁ , B″ ₁ , B ₂ , B′ ₂ , B″ ₂ make further movement impossible. The location of the stopper is selected so that some stress still remains in the cable.

The stability of the structure thus obtained is perfect. In fact, the outward movement of the girders L, L' is limited by the presence of the stoppers, and the inward movement is difficult because of the prestressing of the cables C, C'.

It is naturally possible to devise a three-dimensional structure by arranging several unit elements adjacent to each other from the reference plane concept of the mast as shown in FIGS. 1a to 1c.

Although FIG. 2 shows a mast with a triangular base, it is in no way meant to be limited to triangular base configurations. It is also possible to devise a three-dimensional structure of the bottom surface having n sides from the reference plane concept. For example, triangle, square, rectangle, pentagon, hexagon, etc.

The bottom of the mast referred to here does not necessarily have to have a regular shape. And this provides another important benefit not found in the prior art.

The stability of the mast is increased by rotating the axis of the hinge, and in fact, as shown in Figures 1a to 1c, the axis of the hinge is not perpendicular to the plane of the paper in the figures; It is inclined at a predetermined angle with respect to the vertical line. It is also not a requirement that the rotational axes of the hinges all be inclined at the same angle. Only the hinge axes of the same girder and those between two phase adjacent booms are
It is sufficient that the angles of inclination are the same (for example, H ₁ , H′ ₁ , H″ ₁ , H ₂ , H′ ₂ , H″ ₂ ).

Such a difference in inclination angles, by breaking the symmetry, allows stresses to be distributed along three axes at the hinge level, thus significantly increasing the stability of the entire structure. That's what happens.

Figures 3a and 3b illustrate this difference in angle. Hinge H ₁ , H′ ₁ , H″ ₁ in Figure 3a
The axis of rotation of is perpendicular to the plane of the paper in the figure, while that of the hinges H ₂ , H′ ₂ , H″ ₂ is in the plane of the paper. Possible rotation directions are shown.

This structure is clearly more stable than the structure shown in FIG. This can be understood by considering how the force F is applied at the C point level.

The force F is mostly absorbed by the girders supporting the hinges H ₂ , H′ ₂ , H″ ₂ . This is due to the fact that the structure does not undergo any discernible deformation.The effect of the improvement obtained in this way is that the sets of liners for each digit are positioned at different angles relative to the paper. Appears even larger when tilted with respect to the vertical line.
Another advantage is ease of storage. In other words,
The girder is no longer in the same plane as the boom, which has the effect of reducing the number of parts that can be stacked.

Also, by incorporating a tilt in the axis of rotation of the hinge, the structure does not have an axis that could easily lead to collapse.

Storage means can be used to facilitate storage, for example by using leaf springs (not shown) to secure the cable. it is,
Furthermore, it allows folding only within the base, avoiding interference with the screws and unfolding mechanism. In this retracted position, the cable is completely contained within the bottom surface.

In order to minimize the space occupied, the girder between two adjacent booms should have a length less than twice the smallest side of the base.

If the mast is exposed to a unidirectional flow that creates a thermal gradient, there is a risk that the mast will sag. In such cases, the mast can be slightly twisted to minimize the problem. This purpose is based on the stoppers B ₁ , B′ ₁ ,
This can be achieved satisfactorily by placing B'_{' 1} , B ₂ , B' ₂ , B'' ₂ asymmetrically and by giving different lengths to the cables C', C between two adjacent booms M, M'.
If necessary, it is also possible to reverse the direction of twist at regular intervals.

FIG. 4 shows the draw-out and deployment mechanism associated with the mast of the present invention, which mechanism includes:
It is composed of a plurality of sets of cams fixed to the first ring 8. The ring 8 is moved by one or more motors 9. Each set of cams is a combination of two cams 10 and 11. The number of cam sets is determined to match the number of sides of the base. For example, in a triangular-based structure--illustrated but not meant to limit the invention in FIG.
A set of cams is used.

In order to extend and align the retracted part of the mast, several (in this example three) screws 12 are provided for moving the base plate 13, which base plate 13 is located in the first ring. 8 and board 13
The mast storage part is supported in the cylindrical space 16 between. The screw 12 is driven by a second ring 14. The outer periphery of this second ring 14 is provided with teeth only at a specific location, and only when the cams 10, 11 are not engaged with the retracted portion of the mast to be deployed, the screw 12 is supposed to move.

Note that while the cams 10 and 11 are in operation, one set of the plurality of fingers collectively supports the mast portion that is not deployed. Further, this finger is configured to be retractable, and is driven by the first ring 8.
It is based on The mode of operation of such a finger is illustrated in FIGS. 6a to 6d. There, the finger 15 locks the retracted mast section 19, as shown in Figure 6d, while the cam deploys one of the retracted masts. Then, when the cam is not engaged with the mast section to be deployed (FIG. 6b), the finger 15 is in such a way that the next mast section to be deployed can be moved into the deployed position by actuation of the base plate 13. It will be unlocked. This locking and unlocking of the fingers can be achieved by the actuation of a predetermined random drive device, which device also locks the second ring 1.
It is activated by grooves provided at multiple locations on the periphery of 4.

Figures 5a to 5d illustrate the operation of the deployment mechanism, in which the mast housing part supported on the base plate 13 passes through the ring 8 and is brought specifically to the same level as the boom for deployment purposes. The first expansion of the beams L, L', etc. is performed by the movement of the first cam 10 in the direction of the arrow, which is in contact with the first protrusion 17 provided. The height of this initial development is approximately half the length of the girder. At this time, as the hinge H' ₁ is raised as shown in Figures 5a and 5b, the hinges H' ₁ and H'' ₁ are also pulled upward _. In particular, H″ ₁ is common to the lower section of the mast storage. When the first height position (i.e., the first expanded height position) is reached, a second protrusion 18 is brought into contact with a second protrusion 18 provided at the same level as the intermediate hinges H ₁ and H ₂ of the girder. The action of the second cam 11 causes complete expansion of the spar by moving it to the left in the figure. Note that the first and second protrusions 17 and 18 required for such folding and unfolding operations are both integrated with the axis of each hinge.

At this time, there is interference between the second cam 11 and the movement of the intermediate shaft of the girder during locking in the deployed position (slight expansion or protrusion movement from the position shown in Fig. 1b to the position shown in Fig. 1c). However, on the one hand, it is regulated by the shape of the second cam, and on the other hand, it is regulated by the linear natural motion of the hinge and the circular motion of the cam.

The mast is folded using a folding cam that is offset from the unfolding cams 10 and 11, in other words, has a reverse cam surface shape.
This is done by simply reversing the direction of rotation of the motor.

The advantages of the deployment mechanism according to the invention can be summarized as follows in comparison with the prior art.

(b) The height of the cam is equal to half the length between the two booms, which is less than half the height of that disclosed in U.S. Pat. No. 3,486,279.

(b) Very little friction. While the structure rises,
This is because the movement takes place directly at the hinge height level. As a result, the deployment functionality is lightened. As made clear above, the invention is not limited in any way to the embodiments or to the more actively disclosed modes of application. . To the contrary, the present invention is intended to include all changes that can be made by those skilled in the art without departing from the scope or spirit of the invention.

[Brief explanation of drawings]

Figures 1a to 1c are explanatory diagrams each schematically showing the successive phases during deployment of a mast according to the invention. FIG. 2 is an illustration showing an example of a mast structure according to the invention having a triangular base. FIG. 3 is a diagram schematically showing, in FIGS. 3a and 3b, an embodiment of the hinge in which the axis of rotation thereof is inclined at a predetermined angle with respect to the vertical line, and the inclination is not assumed. This may vary depending on the hinge used. FIG. 4 is a diagram schematically showing a mast deployment mechanism according to the present invention, and FIGS. 5a to 5d are explanatory diagrams each showing its operating mode. FIGS. 6a to 6d are explanatory views showing how the fingers operate on the retractable mast portion, respectively. M: beam, L: girder, C: cable, H: hinge, 8: first ring, 10: cam, 11: cam, 12: screw, 13: board, 14: second ring, 15: finger, 17: First protrusion,
18: First protrusion, 19: Storage mast part.

Claims (1)

Claims: 1. A plurality of basic units L, L', M ₁ , M'₁;L',L'', suitable to be interconnected to form a foldable and deployable section of the mast; _M2 ,
M _{′ 2 ;} L″ _, L, M ₃ , M _{′ 3} ; ，
each of M ₃ , M′ ₃ includes at least one of said basic units L, L′, M, M′; L, L′, M ₁ , M′ ₁ ;
and at least two booms M ₁ , M′ ₁ , each of said basic units being arranged in the direction of deployment of the mast;
M ₂ , M′ ₂ ; M ₃ , M′ ₃ are included, and the ends of the boom M ₁ , M′ ₁ ; M ₂ , M′ ₂ ; M ₃ , M′ ₃ are H″ ₁ −H′ ₂ ,H″ ₂ −H′ ₁ ;H″ ₂ −H′ ₃ ,H″ ₃ −
A pair of cable means C ₁ , C′ ₁ ; C ₂ , C′ ₂ ; C ₃ , interconnecting H′ 2 _; H″ ₃ −H′ ₁ , H″ ₁ − H _{′ 3} diagonally;
C′ ₃ ; and a pair of rod members L, L′; L′, L″ that connect the corresponding ends of the boom in the longitudinal direction;
L'', L, the rod members L, L';L',L''; central portions H ₁ , H ₂ , H ₃ of L'', L and respective ends H' ₁ , H''₁;
H′ ₂ , H″ ₂ ; H′ ₃ , hinge means H ₁ provided at H″ ₃ ;
H′ ₁ , H″ ₁ ; H ₂ , H′ ₂ , H″ ₂ ; H ₃ , H′ ₃ , H″ ₃ and the hinge means to restrict outward movement of the respective rod members. Stopper means provided
B ₁ , B′ ₁ , B″ ₁ ; B ₂ , B′ ₂ , B″ ₂ , and the hinge means allows the rod member to be folded inwardly and unfolded outwardly. each end H' ₁ , H' 2 , H'₃;H" ₁ , H" _{2 ,} H" ₃ of the rod members L, L', L"; The hinge means is connected to each rod member L,
The first deployment cam means 10 of the mast deployment means (8-14) so as to cause partial deployment of L', L''.
Each hinge means having a first protrusion 17 suitable for movement thereon and further arranged in the central part H ₁ , H ₂ , H ₃ of said rod member L, L', L'' ，
A second protrusion 18 adapted to move over the second deployment cam means 11 of said mast deployment means (8-14) in order to move L', L'' outwardly into the fully deployed position. A collapsible and deployable mast, characterized in that it has: 2. A collapsible section L of the mast;
L′, M ₁ , M′ ₁ −L′, L″, M ₂ , M′ ₂ −L″, L,
Each of M ₃ , M′ ₃ has n basic units L, L′,
M ₁ , M′ ₁ ; L′, L″, M ₂ , M′ ₂ ; L″, L, M ₃ ,
M′ ₃ , the booms M ₁ , M ₂ , M ₃ of which have n sides M 1 , M 2 , M 3 common to the preceding section and a first base having n sides M ₁ , M ₂ , M ₃ common to the succeeding section; Determine a second base having n sides M' ₁ , M' ₂ , M' ₃ , and each side of the first and second bases M ₁ , M ₂ , M ₃ ; M' ₁ , M′ ₂ , M′ ₃ are triangles,
A collapsible and deployable mast according to claim 1, arranged in one of symmetrical or asymmetrical shapes to form one of a square, a rectangle, a pentagon, or a hexagon. 3. The hinge means H ₁ , H′ ₁ , H″ ₁ ; H ₂ , H′ ₂ ,
A collapsible and deployable mast according to claim 1, wherein the rotation axes of H″ ₂ ; H3 _{, H′3} , H″ ₃ are inclined at an angle of 90°. 4. The hinge means H ₁ , H′ ₁ , H″ ₁ ; H ₂ , H′ ₂ ,
The collapsible and deployable mast according to claim 1, wherein the rotation axes of H″ ₂ ; H _{3 ,} H′ 3 , H″ ₃ are inclined at an angle other than 90°. 5. The hinge means H ₁ , H' 1 , H _" 1 ; H ₂ , H' ₂ , attached to the same rod means L, L', L _"
The rotation axes of H″ ₂ ; H ₃ , H′ ₃ , H″ ₃ are connected to two adjacent foundation units L, L′, M ₁ , M′ ₁ ; L′, L″,
The collapsible and deployable mast according to claim 1, wherein M ₂ , M'2;L'', L, _{M 3} , M' ₃ are inclined at the same angle. 6. The cable means C ₁ , C′ ₁ ; C ₂ , C′ ₂ ; C ₃ ,
C′ ₃ is the basic unit L, L′, M ₁ , M′ ₁ ; L′,
L″, M ₂ , M′ ₂ ; Vertical corner H″ ₁ of L″, L, M ₃ , M′ ₃
−H′ ₂ ,H″ ₂ −H′ ₁ ;H″ ₂ −H′ ₃ ,H″ ₃ −H′ ₂ ;H″ ₃ −
A collapsible and deployable mast according to claim 1, which is fixed to H _{' 1} , H'' ₁ - H' ₃ by storage means with springs.7. The length of the rod member L; L';L'' between the booms M ₁ , M ₂ , M ₃ ; M' ₁ , M' ₂ , M' ₃ is the minimum size
M ₁ , M′ ₁ , not more than twice the length, so that the space required during storage of the mast 1
6. A collapsible and deployable mast according to claim 1, which makes it possible to reduce 6 to a minimum. 8. The stopper means B ₁ , B′ ₁ , B″ ₁ ; B ₂ , B′ ₂ ,
B″ ₂ ;... is made asymmetrical to allow slight torsion of the mast, and then two adjacent booms M ₁ , M′ ₁ ; M ₂ , M′ ₂ ; M ₃ ,
Said cable means between M′ ₃ C ₁ , C′ ₁ ; C ₂ , C′ ₂ ;
C ₃ , C′ ₃ are of different lengths, so that
A collapsible and deployable mast according to claim 1, wherein distortion of the mast that may occur due to thermal gradients caused by unidirectional flow applied to the mast is reduced. 9. said deployment means (8-14) comprising a plurality of combinations consisting of a first cam 10 and a second cam 11 fixed to the first knurled ring 8, and wherein said first knurled ring 8; A collapsible and deployable mast according to claim 1, characterized in that at least one motor means (9) for driving the toothed ring (8) is provided. 10. The collapsible and deployable mast of claim 9, wherein the number of combinations of said cams matches the number of sides including said base. 11 Screw means in which the means for sequentially extending and aligning the retracted portions of the mast are connected to the second knurled ring 14 associated with the first knurled ring 8 and to the base plate 13 supporting the retracted mast; 1
2, said second toothed ring 14 is adapted to drive said screw means 12, and cams 10, 11 in said cam combination Claim 9: Only certain peripheral parts are toothed so that the screw means 12 is driven by the second toothed ring 14 only while not in mesh with the parts. Foldable and deployable masts as described in Section 1.