JP2008288858A - Automatic extendable antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic extendable antenna with a new structure capable of reliably keeping an extension state after being extended by remote control via an automatic extending means. <P>SOLUTION: The antenna 1 where a plurality of single tubes 2 are telescopically connected is extended by only a force in the longitudinal direction by the automatic extending means. Tapers in a fixed direction are formed at both ends 3, 4 of the single tubes 2 so as to fasten the inner and outer single tubes 2 in an extension state. Both the ends 3, 4 are formed where peripheral lengths are not easily extended compared with the middle part 5 of the single tube 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The invention according to the present invention relates to an automatic extension antenna having a telescopic structure and suitable for holding the length by being extended by an automatic extension means.

There is a telescopic type as one form of the extension type antenna. Also called whip antenna or rod antenna, multiple single tubes of different thickness are connected in a nested manner, and can be extended like a kind of telescope by pulling the inner single tube out of the outer one belongs to.
Patent Document 1 below shows such an antenna used for a mobile phone.

In various devices having not only an antenna but also a telescopic extension structure, when the length is maintained after being extended, some relative rotation may be manually applied to the single tubes. Not only stretching but also twisting a little will ensure the tightness between the single tubes.
Utility Model Registration No. 305272

  Applying relative rotation to a device having a telescopic extension structure as described above is troublesome because it requires another operation in addition to the operation of stretching between the single tubes. Further, unlike a device handled manually, an antenna that can be extended by remote operation tends to be very difficult or costly to perform such a two-step operation.

  In such an antenna, it is desirable that the antenna is firmly fixed in an extended state by simply performing an operation of extending in the longitudinal direction. For an antenna that is maintained in an extended state for a long period of time, a structure in which the extended state is stably maintained even when the single tubes are slightly loosened is desired. In addition, depending on the application and use situation, an insulating antenna that does not cause energization between the distal end side and the proximal end side is required.

  The invention according to the claims has been made in consideration of the above points. An automatic extension antenna having a new structure that can be extended by remote operation via an automatic extension means and can maintain its state reliably. It is to provide.

The automatic extension type antenna according to claim 1 has a plurality of single pipes connected to a telescopic type (whipped type), and a length direction by an automatic extension means (which is remotely operated to extend the antenna by a motor or the like). An automatic extension antenna that can be extended only by force on
・ Tapered in a certain direction at both ends of the single tube (towards the tip) so that the inner and outer single tubes are tightened in the stretched state (the outer surface of the inner single tube and the inner surface of the outer single tube are tightened) Thinned) is formed,
-Both end portions are characterized in that the circumference is less likely to extend than the middle portion of the single tube (that is, the portion other than both end portions).

When such an automatic extension antenna is extended by the automatic extension means, the inner and outer single tubes are tightened by the action of the taper formed at both ends of the single tube, and kept in the extended state.
When a person extends with his / her hand, the tightening state can be ensured by pulling and extending the antenna and applying some relative rotation (twisting) between the single tubes. However, in an automatic extension type antenna that is extended only by a force in the length direction by the automatic extension means, the single tubes cannot be relatively rotated. Therefore, in this automatic extension type antenna, both ends of the single tube are made difficult to extend the circumference compared to the middle part of the single tube (that is, by making a difference in material, thickness, reinforcement state, etc.) In both ends, it is difficult to stretch in the circumferential direction even when force is applied). As a result, the single tubes are tightly tightened even if they are expanded only by the force in the length direction and are not twisted. As a result, the antenna is reliably maintained in the extended state.

  The self-expanding antenna according to claim 2 further has a taper formed in a middle portion of the single tube (a portion other than both end portions as described above). The end portion on the thick side is characterized in that it has a dimensional relationship that rubs against the region on the narrow side of the middle portion of the outer single tube (the region about half in length).

In an automatic extension antenna where twisting is not applied by simply tightening the ends of a single tube (that is, the end on the thick side of the single tube inside and the end on the thin side of the single tube outside) The extended state may not be reliably maintained for a long period of time.
In that respect, the dimensional relationship is as described above, and not only the ends of the single tubes, but also the end on the thick side of the single inner tube and the region on the thin side of the middle portion of the single single tube If there is a tightness that rubs between the two, the stretched state is ensured. This is because even if the tightness between the ends of the single tube is loosened for some reason, the antenna is maintained in an extended state due to the tightness between the end and the middle part.

  In the self-extending antenna according to claim 3, the middle portion of the single tube is made of GFRP (glass fiber reinforced plastic), and both ends of the single tube are made of CFRP (carbon fiber reinforced plastic). It is characterized by being formed.

  Since CFRP has a higher elastic coefficient than GFRP and is difficult to stretch, if the material of each part is determined as described above, both ends are less likely to stretch than the middle part of a single tube as described in claim 1 Is easy. In addition, since the GFRP used for the middle part is less likely to pass current, it is possible to prevent energization in the length direction in the extended state, which is suitable when the antenna needs insulation.

  The automatic extension antenna according to claim 4 is mounted on an artificial satellite.

  An antenna mounted on a satellite is not something that can be stretched by a person with a hand, but is usually stretched only by a force in the length direction of an automatic stretching means. Actually difficult. Once it is stretched, it is not shrunk again and needs to be kept in a stretched state for a long time. In that respect, an antenna having the features described above (of any claim) is very advantageous. In addition, since it is not preferable for various observations that current flows along the antenna due to the influence of electromagnetic waves or the like, the use of GFRP and CFRP as materials as described above is particularly advantageous for use in an artificial satellite.

The self-extending antenna of the claimed invention can be extended only by the force in the length direction by the automatic extension means, and the single tubes are firmly tightened even if no twist is applied, and the extended state is ensured. Kept.
By appropriately setting the dimensional relationship between the inner and outer single pipes, it is possible to more reliably maintain the extended state.

The automatic extension antenna of the invention can strengthen the tightness of the single tubes in the extended state by forming the middle part of the single tube with GFRP and including CFRP at both ends of the single tube. An insulating antenna that does not energize in the length direction can be configured.
Moreover, when mounted on an artificial satellite, it is extremely preferable in terms of operability for extension, maintenance characteristics of the extension state, observation characteristics based on insulation, and the like.

  An example showing an embodiment of the invention will be introduced with reference to the drawings. FIG. 1 shows a main part of an automatic extension antenna 1 in an assembled state and extended state. FIG. 2 shows a single tube 2 that is a component of the antenna 1. In both figures, the thickness and taper of the single tube 2 are exaggerated. The automatic extension antenna 1 is mounted on an artificial satellite and transmits / receives various signals to / from a base on the earth.

  Each cylindrical single tube 2 has a slightly larger diameter than the single tube 2 on the front side (more distal side), and other single tubes on the front side, the rear side, or both sides as shown in FIG. 2 are nested in order. Each single tube 2 is tapered so that the distal end side is slightly thinner than the proximal end side. When the antenna 1 is extended, the proximal end portion 4 of the front single tube 2 is a single tube closer to the next proximal end. 2 is fitted inside the tip 3. After the extension, the fitting parts (the base end part 4 of each single pipe 2 and the tip part 3 of the single pipe 2 on the rear side) are tightened and fixed and maintained in the extended state. The diameter of the proximal end of the single tube 2 closest to the proximal end is several tens of mm, the diameter of the distal end of the single tube 2 at the most distal end is several mm, and the total length of the antenna 1 when extended is several meters. is there.

  Each single pipe 2 shown in FIG. 2 is manufactured by winding a full length part including a middle part 5 by winding a plurality of layers of GFRP sheets. A mold (not shown) is used for winding the sheet, and the sheet is wound around the outside of the mold. A taper is formed in advance on the mold, and the taper is formed on the single tube 2 so that the end portion 3 side is narrowed by winding a sheet on the outside thereof. The distal end portion 3 and the proximal end portion 4 are formed with a taper having a larger angle than that of the middle portion 5 excluding them.

  A part of the distal end portion 3 (portion with a large taper angle) in each single tube 2 and a region closest to the distal end and the entire region of the base end portion 4 (portion with a large taper angle) than the GFRP sheet. The CFRP sheets 3a and 4a, which are difficult to stretch, are reinforced by wrapping them in multiple layers.

  The inner diameter and outer diameter of the single tube 2 are determined as follows. That is, each single tube 2 is a single tube 2 in which the inner peripheral surface of the single tube 2 overlaps with the inner side (front end side) when the antenna 1 extends in an area of about half of the total length on the distal end side in the middle portion 5. It is determined so as to rub against the outer peripheral surface of the base end portion 4. By the time the antenna 1 is fully extended, the way of rubbing gradually increases according to the taper.

  Surface grinding with a grindstone is performed on the outer surface side (CFRP sheet 4a) of the base end portion 4, and when it is extended and assembled, it is fastened to the single tube 2 on the outer side (that is, the rear side) on the ground surface. The dimensions have been adjusted to fit with the fit. The grinding of the outer surface of the base end portion 4 was performed so that a taper having a larger inclination than the middle portion 5 was accurately formed as described above, and the fitting between the single tubes 2 was ensured. . Note that the outer surface of the CFRP sheet 3a wound around the outer periphery of the tip portion 3 is also subjected to surface grinding for smoothing.

  As an automatic extension means for the antenna 1, a spring wire wound around a drum (connected to a driving source such as a motor) in advance is extended to the tip side inside the antenna 1, or compressed air is supplied to the antenna 1. What is blown into the inside of each of them (both not shown) can be employed.

  When each single tube 2 extends, another single tube 2 moves closer to the tip inside each single tube 2, and the base end portion 4 of the inner single tube 2 is immediately outside the single tube 2. After reaching the center of the middle portion 5 of the single tube 2, the outer peripheral surface of the base end portion 4 of the inner single tube 2 extends while rubbing against the inner peripheral surface of the outer single tube 2. Thereafter, when each single tube 2 moves to the state shown in FIG. 1, the base end portion 4 and the outer side (rear side) of the inner (front) single tube 2 reinforced with CFRP having a property that the circumference is relatively difficult to extend. The distal end portion 3 of the single pipe 2 is tightly tightened, and the extended state is fixed by such fitting.

  Such an automatic extension antenna 1 is extremely convenient when used on an artificial satellite. It can be stretched only by the force in the length direction by the simple automatic stretching means as described above, and when it is stretched once, the state is firmly maintained, and the GFRP sheet and the CFRP sheet are extremely lightweight. This is because there are various advantages such as being configured, and further, because of the insulation by the GFRP sheet, measurement information to be transmitted and received is hardly disturbed.

  Since GFRP which is difficult to pass current is used in the middle part 5 of each single tube 2, the antenna 1 functions as a general antenna only in a short part using CFRP. However, the antenna 1 having such a structure is useful when high-frequency and short-wave radio waves are used in an artificial satellite or the like.

  Note that the configuration of the antenna according to the invention is not limited to this example. It is preferable to change the length, material, and the like depending on the application, the frequency of the radio wave, and the like. For example, the entire single tube may be formed of only CFRP (or using CFRP together with other materials), and CFRP may be further wound on both ends for reinforcement. It is also possible to form the entire single tube with a metal such as aluminum and wind CFRP or other reinforcing members around both ends.

It is a longitudinal cross-sectional view which shows the principal part of the automatic extension type antenna 1 of the state assembled and extended. The thickness and taper of each single tube 2 are exaggerated. It is a longitudinal cross-sectional view which shows the single tube 2 which is a component of the antenna 1 in detail. The thickness and taper of each single tube 2 are exaggerated as in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2 Single tube 3 Tip part 4 Base end part 5 Middle part

Claims (4)

A plurality of single tubes are telescopically connected, and an automatic extension antenna that is extended only by a force in a length direction by an automatic extension means,
Both ends of the single pipe are tapered in a certain direction so that the inner and outer single pipes are tightened in an extended state, and the circumference of each end is less likely to extend than the middle part of the single pipe. A self-extending antenna characterized by being formed as described above.   The taper is also formed in the middle part of the single tube, and when it is extended, the end on the thick side of the inner single tube rubs against the region on the narrow side of the middle part of the outer single tube. The self-extending antenna according to claim 1, wherein the antenna is related.   The self-extending antenna according to claim 1 or 2, wherein a middle portion of the single tube is formed of GFRP, and both ends of the single tube are formed including CFRP.   The automatic extension antenna according to any one of claims 1 to 3, wherein the antenna is mounted on an artificial satellite.

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