JP2516701B2 - Extension mast - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an extendable / shortenable extension mast used for a space station and other structures. More specifically, the present invention relates to an extension mast that is lightweight, has a small occupied volume in the shortened state, and high rigidity in the extended state.

[Prior Art] Conventionally, it has been planned to employ an extension mast as a structural member of a space station or the like. This extension mast is a beam-shaped structure that can be extended and shortened.It is mounted on a rocket or space shuttle in a state where it is shortened to reduce its occupied volume and launched into space, and this mast is extended in space. It is a beam-shaped structure.

As an example of such an extension mast, there is an extension mast having a structure in which a longitudinal member is constituted by a long rod-shaped member which is elastically deformable, and a plurality of the longitudinal members are connected to each other by an elastically deformable horizontal rail member. is there. This is put into a shortened state by elastically deforming the above-mentioned longitudinal member into a coil shape, and when the mast is extended, the mechanism that keeps this mast in a shortened state is released, and this longitudinal member is extended. Is expanded linearly by the elastic force to form a linear beam-shaped mast. Although such a structure has a simple structure, there is a problem that the rigidity in the expanded state cannot be increased so much. In particular, when the structure such as a space station becomes large, if the rigidity of the mast used for this structure is low, the cycle of vibration of this structure as a whole becomes long, making it difficult to damp or control this vibration. It causes problems such as

Also, as an example of another type of extension mast, rigid members that form a truss are rotatably connected by pins or the like,
There is a joint type in which these members are rotated and folded to be in a shortened state, and these members are linearly expanded to form a beam-shaped mast. Although the extension mast of this type can increase the rigidity, it has a problem that the structure becomes complicated and the weight also increases as the structure becomes complicated.

Another type of extension mast is the US
NASA Contractor Report 172461 (1986) "Batten
There is an extension mast disclosed in "Augumented Triangular Beam". This is a triangular truss shape in which each vertex of a plurality of triangular batten members is connected by three longiron members. The longelon members are pivotally attached by a pin so as to pivot at a central portion between adjacent batten members, and the mast is shortened by pivotally folding the longlon members.
Further, in this device, the above batten member is composed of three beams which can be elastically bent and deformed, and a cord is stretched diagonally between the adjacent batten member and the adjacent longlon member. There is. When the mast is in the extended state, the beams forming the batten member are elastically curved by receiving a compressive load, and the elastic force of these beams stretches the cord in a tensioned state. Is configured. But something like this
The longlon member is made of a rigid member, but the batten member is made of an elastically deformable beam, so that the rigidity of the entire mast cannot be increased so much.

As described above, in all the conventional masts, the structure is simplified, the weight is reduced, the storage efficiency and the like conflict with the rigidity such as extension.

[Problems to be Solved by the Invention] The present invention has been made based on the above circumstances, and provides an articulated extension mast that has a high rigidity, a simple structure, and a lightweight structure. .

[Means for Solving the Problem] The present invention is formed by connecting a plurality of cross rail members, ie, batten members, with a plurality of longitudinal members, ie, longlon members, and adjoining batten members and adjoining longlon members. A diagonal member, that is, a diagonal member is diagonally arranged in a square portion. The diagonal member is composed of a plurality of sliding members, and the sliding members are configured to be slidable in the axial direction with respect to each other. The diagonal member is expandable and contractible and extends beyond a certain length. It is configured not to. The longlon member is composed of two rotating members, one end of which is pivotally attached to the other, and the other end of which is pivotally attached to the batten member. . Further, these rotating members are expanded in a straight line, and when the diagonal member is fully extended, they are overcentered, and these rotating members are maintained in the expanded state.

This overcenter means that the two ring members, for example, the above-mentioned first and second rotating members extend, and the pivot center is located at one end where the rotating members are pivotally connected to each other. After matching with the center line connecting the pivot centers of the ends, further rotate to move the pivot center of this one end beyond the above center line to the other side of this center line and hit the stopper etc. It is to be locked in contact.

Further, the rotating member constituting the longlon member has a web portion and a pair of flange portions integrally formed on both side edge portions of the web portion, and its cross-sectional shape is H-shaped. Then, in a state in which these rotating members are rotated and folded, the flange portion of the first rotating member is configured to overlap the inside of the flange portion of the second rotating member. The web portions of the first and second rotating members are displaced to one side with respect to the pivotal centers of mutual rotation of the rotating members at one end of the rotating members, and At the other end, it is arranged so as to be inclined with respect to the center line of the flange portion so as to be displaced to the other side with respect to the center of pivotal attachment of the rotating member and the batten member.

Further, according to the embodiment of the present invention, a locking mechanism is provided at the pivotal pivotally attaching portions of these pivoting members, and these rotations are caused by the overcenter of the pivoting member and the mechanical locking of the locking mechanism. Keep the moving member in the deployed state.

[Operation] According to the present invention, the two rotating members constituting each longlon member are rotated and folded, the diagonal member is shortened, the batten members are overlapped with each other, and the extension mast is in a shortened state. Become. Further, the rotary members of each of the above-mentioned longlon members are deployed so as to be arranged in a straight line with each other, and each of the diagonal members is extended, so that the extension mast is in the extension state. In this case, in the fully extended state of the diagonal member, the rotating members forming the longlon member overcenter each other, and this overcenter locks the longron members in a linearly expanded state.

The extension mast of the present invention is a joint type in which rigid members are rotatably connected, and has a high rigidity. Also, since the longlon member is linearly locked by the overcenter of the rotating member, the structure is simple.
Moreover, it can be configured to be lightweight.

That is, since the diagonal member is fully extended when the rotating member is linearly extended,
The diagonal member elastically expands and deforms, and the other members also elastically deform due to the tension of the diagonal member. In this state, a compressive load acts on the longonron member composed of the pair of rotating members, and urges the rotating members toward each other in the folding direction. The state where the mutual pivoting center points of the one ends of these rotating members are located on the center line connecting the pivoting center points of the other ends of these rotating members is the maximum extension state of this longileon member. However, from this state, these rotating members further rotate, the pivot center of one end moves to the other side beyond the above center line, and the rotation is restricted by a stopper or the like. In this state, the urging force of the elastic deformation of the diagonal member and other members urges these rotating members in the direction of rotating to the other side and is locked by the stopper or the like. Therefore, the longlon member composed of these rotating members is locked in the extended state, and a special locking mechanism for locking the diagonal member in the extended state is not required, and the structure is simple and lightweight.

Further, when the mast is in the extended state, the longon member is overcentered in the state where the diagonal member is fully expanded and a tensile load is applied as described above, and the load acts on each member and their connecting portion. And
Since the internal load is applied to the mast from the beginning, the play between the members is removed, and the rigidity is further increased.

Further, in the present invention, the rotating member that constitutes the above-mentioned longlon member has a web and a pair of flanges integrally formed on both side edges of the web, and its cross-sectional shape is H-shaped. Then, in a state in which these rotating members are rotated and folded, the flange portion of the first rotating member is configured to overlap the inside of the flange portion of the second rotating member.
Further, the webs of the first and second rotating members are displaced to one side with respect to the center of pivotal attachment of these rotating members at one end of these rotating members, and to the other side of these rotating members. At the end portion, it is arranged so as to be inclined with respect to the center line of the flange so as to be displaced to the other side with respect to the center of pivotal attachment of the rotating member and the batten member.

Therefore, since the flange portion of the first rotating member is housed inside the flange portion of the second rotating member in a nested manner, the occupied volume in the folded state of this longiron member is small, and the storage efficiency is improved. improves. In this case, in a normal die member having an H-shaped cross section, its web portion is arranged at the center of the flange portion. In such a structure, when the flange portions are stacked in a nesting manner as described above, the edge portion of the flange portion of the first rotating member interferes with the web portion of the second rotating member to cause the first rotation. The flange portion of the moving member is not completely housed inside the flange portion of the second rotating member.

However, according to the present invention, in the mutual pivoting portions of the one ends of the rotating members, the web portion is offset to one side of the pivoting center with respect to the center line of the flange portion. It is arranged to be inclined. Therefore, in the mutually pivoting portion at this one end, the flange portion of the first rotating member does not interfere with the web portion of the second rotating member, so that the first rotating member is The flange part of the second
It is possible to completely fit and store the inside of the flange portion of the rotating member in the form of a nest, and the storing efficiency is improved as described above.

In the configuration of the present invention as described above, at the other end of the rotating member, the web portion of the rotating member is deviated to the other side with respect to the pivot center of the other end, At the other end, the flanges of these pivoting members interfere with the web and cannot nest together. However, since the other end of the rotating member is pivotally attached to the batten member and originally cannot be fitted into each other in the retracted state of the extension mast, this does not reduce the storage efficiency. .

Further, according to the embodiment of the present invention, the pivotal portion of the rotating member is provided with a mechanical lock mechanism in addition to the above-mentioned overcenter, so that the extension mast is in a deployed state. Therefore, when a load is applied from the outside to the pivotally mounted portion of the rotating member, the lock due to the overcenter is not released undesirably.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
1 to 6 show a first embodiment of the present invention. This embodiment is an extension truss used in a space station structure or telescopic boom for accessing the space shuttle from the space station. 1 and 2 show a part of the extension truss, the upper half of which is in an extended state and the lower half is in a shortened state.

This extension mast is adjacent to adjacent batten members 1 and a plurality of horizontal rail members or batten members 1 having a substantially triangular shape, a plurality of longitudinal members or longlon members 2 for connecting the respective apexes of the batten members 1, respectively. And a plurality of diagonal members, that is, diagonal members 3 arranged along a polygonal line of a quadrangle formed by the longlon member 2.

As shown in FIG. 2, each of the above batten members 1 is configured by connecting both end portions of three mold members 11a having an H-shaped cross section made of an aluminum alloy, a composite material or the like with connecting members 11b, and having a substantially regular shape. It has a triangular frame shape.

As shown in FIG. 4, the diagonal member 3 is composed of a plurality of sliding members such as a sliding rod 31 and a hollow sliding tube 32. The diagonal member 3 is configured to expand and contract by being slidably inserted into and being slid on each other. Further, stoppers 43 and 44 are provided at the ends of the sliding rod 31 and the sliding tube 32, and the maximum extension length of the diagonal member 3 is regulated by abutting them. . In addition, this diagonal member 3
Since only tension is applied to these, these diameters are made thin. Mounting portions 41, 42 are formed at both ends of the diagonal member 3, and these mounting portions 41, 42 are formed.
Is the connecting member 11b at the apex of the adjacent batten member 1.
Is rotatably connected to.

Further, the above-mentioned longiron member 2 is shown in FIGS.
As shown in the figure, the first and second two rotating members 21, 2
It consists of two. These rotating members 21 and 22 are made of an aluminum alloy, a composite material, or the like, and have a web portion 25 and a flange portion integrally formed on both side edges of the web portion.
26, and has a beam shape with an H-shaped cross section. And
Both end surfaces of these web portions 25 are formed as stopper surfaces 30a and 30b. Then, one ends of the rotating members 21 and 22 are pivotally attached to each other by a pin 23 so as to be rotatable.
The other ends of the rotating members 21 and 22 are respectively provided with pins 24.
Are rotatably connected to the apexes of the adjacent batten members 1. Therefore, the rotating members 21 and 22 rotate in a plane including the central axis of the extension mast, and the longlon member 2 including these rotating members is configured to be foldable and expandable.

Then, the rotating members 21 and 22 are rotated so as to be arranged linearly, and the extension mast is extended by linearly deploying the longlon member 2. In this case, the diagonal member 3 is also fully extended,
These diagonal members 3 act as brace members to increase the rigidity of this mast. Also, in this case,
In the state where the diagonal member 3 is fully extended, the pivot centers of the pins 23 and 24 that pivotally pivot the pivot members 21 and 22 have a predetermined amount as shown in FIG. Only O _{C is} overcentered, the stopper surfaces 30a of the web portions 25 come into contact with each other, and are locked in this state. In this overcentered state, the front end surfaces of the web portions 24 of the rotating members 21, 22 come into contact with each other and act as stoppers. In this state, the diagonal member 3 is fully expanded and a predetermined tension is applied, and the elasticity of the diagonal members 2 causes the rotating members 21, 22 to rotate.
Is maintained in the over center state.

This overcenter means, as shown in FIG. 5, two link members such as the above-mentioned first and second rotating members.
21 and 22 are advanced, and the center of the pin 23 that pivotally attaches one ends of these pivoting members to each other connects the center of the pin 24 that pivotally attaches the other ends of these pivoting members 21 and 22. After fitting on the center line A, it is further rotated so that the center of the pivot pin 23 at this one end moves over the center line A to the other side of the center line A, and the stopper, for example, the above-mentioned web portion. That is, the stopper surfaces of the end surfaces of 25 come into contact with each other and are locked.

In this state, a tensile load acts on the diagonal member 3 and a load also acts on other members,
These are elastically deformed. Then, due to these elastic deformation forces, a load for compressing the longonron member 2 is applied, and the rotating members 21 and 22 in the above-described overcenter state move in opposite directions. It is urged in the bending direction, that is, in the direction in which the pin 23 pivotally connecting these members in FIG. 5 moves to the left side in the drawing. In this case, the rotating members 21 and 22 cannot be rotated further because the stopper surfaces 30a of the web portions 25 contact each other, and are locked in this overcenter state by the elastic force. It

It should be noted that the center of the pin 23 that pivotally attaches one ends of the pivoting members to each other connects the center of the pin 24 that pivotally attaches the other ends of the pivoting members 21 and 22 to the center line A. The state that matches the above is the maximum deployed state, that is, the maximum length state of the longlon member 2, and the overcenter state is a state in which it is bent or shortened to some extent from the maximum deployed state of the longon member 2. Therefore, in order to cancel the overcenter state, the rotating members 21 and 22 should be pressed from the left side in FIG. 5 with a certain load to extend the longlon member 2 to the maximum deployed state. Since this must be done, this overcenter state is stably maintained in this state. Therefore, there is no need for another lock mechanism for fixing the longlon member 2 composed of these rotating members in the extended state, and the structure is simplified,
In addition, weight reduction can be achieved.

Further, in this state, a tensile load is applied to each of the diagonal members 3 as described above, and the rotating members 21 and 22 of the longlon member 2 and the mold member 1 of the batten member 1 are also used.
A compressive load acts on each of 1 and an internal load is generated in advance on the extension mast by these loads. Therefore, the play of the connecting portion of each member is removed by this internal load, so that the rigidity of the extension mast can be further enhanced.

The width of the second rotating member 22 is equal to the width of the first rotating member.
It is formed wider than the width of 21 by the thickness of the flange 26.
As shown in the figure, in a state where these rotating members are folded, the flange portion 26 of the first rotating member 21 becomes the second rotating member.
It is configured to overlap the inside of the flange portion 26 of 22.

Then, the web portions of the first and second rotating members described above.
25 is biased to one side with respect to the center of the pin 23 pivotally connecting the rotating members to each other at one end of these rotating members, and to the rotating members at the other end of these rotating members. These web portions 25 are arranged so as to be inclined with respect to the center line of the above-mentioned flange portion 26 so as to be displaced to the other side with respect to the center of the pin 24 pivotally attached to the above-mentioned batten member.

Therefore, the flange portion 26 of the first rotating member 21 is
Since the rotary member 22 is stored inside the flange portion 26 of the rotary member 22 in a nested shape, the occupied volume when the longlon member 2 is in the folded state is small, and the storage efficiency is improved. In this case, in a normal die member having an H-shaped cross section, its web portion is arranged at the center of the flange portion. In such a thing,
When the flange portions are stacked one on top of the other as described above, the edge portion of the flange portion 26 at one end of the first rotating member 21 interferes with the web portion 25 at one end of the second rotating member 22. The flange portion of the first rotating member is not completely housed inside the flange portion of the second rotating member.

However, according to the present invention, the center line of the flange portion is arranged so that the web portion is offset to one side of the center of the pivot pin at the pivot portions of the one ends of the rotating members. It is arranged to be inclined with respect to. Therefore,
The flange portion 26 of the first rotating member 21 is the web portion of the second rotating member 22 at the mutual pivoting portions at the one ends.
Since it does not interfere with 25, it is possible to completely fit and store the flange portion of the first rotating member inside the flange portion of the second rotating member, as described above. The storage efficiency is improved.

In the configuration of the present invention as described above, the rotating members 21, 2
At the other end portion of 2, the web portion 25 of the rotating member is deviated to the other side with respect to the center of the pivot pin 24 at the other end portion. The flange portion of the member interferes with the web portion and cannot be telescopically fitted together. However, the other end of the rotating member is pivotally attached to the batten member 1 and originally cannot be fitted into each other in the retracted state of the extension mast.
This does not reduce the storage efficiency.

The extension mast of the present invention configured as described above is mounted on a rocket or a space shuttle in a shortened state, is launched into outer space, and then is extended. At the time of this extension, an appropriate extension device (not shown) sequentially deploys the longlon member 2. In addition, when using this extension mast as a telescopic boom, deploy it properly.
The shortening device sequentially expands or folds the longlon member to expand and contract this mast.

Also, FIGS. 7 to 11 show a second embodiment of the present invention. In this embodiment, a mechanical lock mechanism is provided on the pivotal portion of the rotary member that constitutes the longlon member, and both rotary members are locked in the deployed state by both the lock mechanism and the over center.

That is, 41 is a first rotating member and 42 is a second rotating member. The rotating members 41 and 42 are pivotally attached to each other by a pin 43. A lock mechanism 45 is provided on the pivotally connecting portions of the rotating members 41, 42. The lock mechanism 45 will be described below.

A slit-shaped through hole 46 is formed at the upper end of the second rotating member 42. A plate-shaped lock body 51 is arranged in each of the through holes 46, and the lock body 51 is pivotally attached by a pin 53. Further, abutting portions 52a and 52b are formed on the outer edge portions of these lock bodies 51, and these abutting portions 52a and 52b are arranged in a substantially V shape at a predetermined angle.

In addition, on both sides of the lower end of the first rotating member 41,
A slit-shaped lock groove 54 is formed. Then, by rotating the lock body 51, these lock bodies 51 are fitted into the lock grooves 54, and the rotation members 41 and 42 can be locked in the deployed state. It is configured.

When the extension mast is in the shortened state, the lock mechanism 45 is in a state in which the lock body 51 is rotated and pulled out from the lock groove 54 as shown in FIG. In this state, as shown in the lower part of FIG. 7, the rotating members 41 and 42 are in a state of being rotated around the pin 43 and folded.

When the extension mast is in the extended state, the rotating members 41, 42 are sequentially moved from the tip end portion of the extension mast.
Is deployed in a straight line and locks by overcenter. In this way, the extension mast is sequentially extended, but the rotating members 41, 4 that have been deployed in association with this extension.
2 moves in the axial direction as shown by arrow A in FIG. At this time, a storage mechanism for this extension mast (not shown)
The drive projection 60 projecting from the contact part 52b of the lock body 51
The lock body 51 in the direction of arrow B,
As shown in FIG. 9, the lock body 51 is fitted into the lock groove 54 to lock the rotating members 41 and 42 in the expanded state in order.

When the extension mast is changed from the extension state to the shortened state, the extension mast is sequentially folded from the base end portion. In this case, as shown in FIG. 11, the rotating member
Since 41 and 42 move in the opposite direction to the arrow C, the drive projection 60 abuts the abutting portion 52a of the lock body 51, and the lock body 51 rotates in the direction of the arrow D to release the lock. Being done.

In this embodiment, since the rotating members 41 and 42 can be locked in the expanded state not only by the overcenter but also by the locking mechanism 45, the locking can be more reliably performed. In particular, when an object collides with the rotating member of the mast in the extended state from the outside, the locking mechanism 45 can prevent the rotating member from rotating beyond the over center due to the collision, Improves reliability.

Further, FIGS. 12 to 14 show a third embodiment of the present invention. This is one in which a hook-shaped lock member 71 having an inclined surface at the tip is pivotally attached by a pin to the upper end of the second rotating member 42 '. Also, the first rotating member
A rectangular lock hole 73 is formed at the lower end of 41 '.
Then, these rotating members 41 ', 42' are formed, and the lock body 71 engages with the edge of the lock hole 73 to lock these rotating members 41 ', 42' in the deployed state. . In addition,
The lock body 71 is biased in the lock direction by a spring (not shown) built in the support portion of the pin 72.

In the third embodiment, when the extension mast is extended, the rotary members 41 'and 42' are linearly expanded, so that the slope portion of the tip end of the lock body 71 is locked in the lock hole 73. Abutting the edge of the lock body against the biasing force of the spring.
71 rotates, and the lock body 71 is automatically engaged with the edge of the lock hole 73 by the urging force of the spring.

When the extension mast is shortened, the rotating member 41'42 'in the deployed state moves in the direction of arrow E in FIG. 13 to drive the projecting protrusion of the extension mast. The portion 80 contacts the lock body 71, and the lock body 71 is rotated in the direction of arrow F to unlock the lock body 51.

The present invention is not limited to the above embodiment, and various modifications can be made. For example, the batten member need not be triangular, but may be square or some other shape.
Further, the number of longiron members arranged between the batten members is not limited to three, and may be four or more.

Further, the structures of the longlon member and the diagonal member are not limited to those described above. Further, these rotating members do not have to rotate in a plane including the central axis of the extension mast, but may rotate in a plane including, for example, the mold member of the batten member.

Moreover, it is understood that the present invention can be used not only as a space station structure but also as other structures.

[Effects] As described above, the present invention has a structure in which rigid members are connected, and since the longlon member is overcentered and locked in a state where tension is applied to the diagonal member,
A load is applied to the extension mast, and the mast has extremely high rigidity. Moreover, the structure is simplified and the weight can be further reduced. In addition, the rotating member of the above-mentioned Longiron member has an H-shaped cross section,
Since the web part is inclined with respect to the flange part,
In the folded state, these flange portions are fitted to each other without interfering with the web portion, so that the volume in the folded state is small and the volumetric efficiency is improved.

[Brief description of drawings]

1 to 6 show a first embodiment of the present invention. FIG. 1 is a perspective view, FIG. 2 is a side view, FIG. 3 is a perspective view of a longlon member, and FIG. 4 is a diagonal member. FIG. 5 is a vertical cross-sectional view of the longelon member in a developed state, and FIG. 6 is a vertical cross-sectional view of the longelon member in a folded state. 7 to 11 show a second embodiment of the present invention. FIG. 7 is a perspective view of a longiron member, FIG. 8 is a front view of the longiron member, and FIG. 9 is a longitudinal section of the longron member. FIG. 10, FIG. 10 and FIG. 11 are vertical sectional views for explaining the operation of the lock mechanism. 12 to 14 show a third embodiment of the present invention, FIG. 12 is a perspective view of a longiron member, FIG. 13 is a longitudinal sectional view of the longiron member, and FIG.
It is a perspective view of the longiron member seen from the opposite direction to the drawing. 1 ... Batten member, 2 ... Longiron member, 3 ... Diagonal member, 21, 22 ... Rotating member, 31, 32 ... Expandable member

Claims (4)

(57) [Claims] 1. A plurality of batten members arranged laterally and acting as horizontal rail members, a plurality of longelon members longitudinally arranged between these batten members and acting as longitudinal members, and these adjacent longirons. Shortened composed of a plurality of diagonal members diagonally arranged between the member and the joint between the adjacent batten member
In the extendable mast structure, the diagonal member is composed of a plurality of elastic members which are slidable with respect to each other. When the diagonal member is extended to a predetermined length, further extension is impossible, and the longlon The member is composed of first and second rotating members whose one ends are pivotally attached to each other,
The other ends of the rotating members are rotatably pivotally attached to the batten member, and the rotating members are deployed while rotating and the diagonal members are fully extended. These longelon members are fixed in a deployed state when the pivotal centers of the moving members and the pivotal centers of the rotating members and the batten member are overcentered, and also constitute the longonron member. The rotating member has a web portion and a pair of flange portions integrally formed on both side edges of the web portion, and its cross-sectional shape is H-shaped, and these rotating members are rotated and folded. Then, the flange portion of the first rotating member is configured to overlap the inside of the flange portion of the second rotating member, and the webs of the first and second rotating members are the same as those of the rotating member. These rotating parts at one end The members are deviated to one side with respect to the center of pivotal movement of the members, and the other ends of the pivoting members are deviated to the other side with respect to the pivotal centers of the pivoting member and the batten member. The extension smart body, which is arranged so as to be inclined with respect to the center line of the flange. 2. The batten member has a triangular shape, and three longelon members are respectively arranged between adjacent batten members, and the longron members are respectively provided at respective apexes of the triangular batten members. The extension mast according to claim 1, wherein the extension mast is pivotally attached. 3. The extension mast according to claim 1, wherein the rotating member constituting the longlon member is rotated and expanded and folded in a plane including a central axis of the mast. . 4. A lock mechanism for locking the rotary members in a deployed state is provided at a rotary pivotally connecting portion between the first rotary member and the second rotary member which constitute the longlon member. The extension mast according to claim 1, wherein the extension mast is provided.