EP1287583A1

EP1287583A1 - Relay antenna masts for cellular radio-telecommunication system

Info

Publication number: EP1287583A1
Application number: EP01929696A
Authority: EP
Inventors: Hossein Safakhah
Original assignee: Bouygues Telecom SA
Current assignee: Bouygues Telecom SA
Priority date: 2000-04-25
Filing date: 2001-04-25
Publication date: 2003-03-05
Also published as: WO2001082406A1; CA2377965A1; US6809702B2; US20020149536A1; PL351522A1; FR2808124A1; FR2808124B1

Abstract

The invention concerns relay antenna masts for a cellular radio-telecommunication system, characterised in that it comprises: a mast foot (1); at least an arm (3) which is mounted pivoting on said mast foot (1) and bearing at least an antenna (5); means for locking said arm in a position wherein the antenna(e) are in high position, said arm (3) being adapted, when the locking means are released, to be pivoted about its pivot pin (4) down to a position where at least one antenna is at a height where an operator can operate thereon at the mast foot.

Description

CELL RADIO TELECOMMUNICATIONS SYSTEM RELAY ANTENNA MATS

GENERAL FIELD OF THE INVENTION AND PRESENTATION OF

THE STATE OF THE ART

The present invention relates to masts of relay antennas for cellular radio-telecommunications system.

Conventionally, in urban areas, masts of relay antennas are located on raised sites, such as building terraces, and can have a height of up to four meters, or even beyond.

It is necessary to be able to intervene regularly on the antennas carried by these masts, in order to carry out their maintenance and also to adjust their orientation in site (Tilt adjustment) and in azimuth. Due to the height of the antennas on the mast and the need to access them, personnel are frequently subject to the risk of falling.

For reasons relating in particular to space and aesthetic issues, it is difficult to envisage providing around these masts bodyguards which extend over the entire height of said masts and which would allow interventions to be completely secure. There is therefore a need for a solution capable of perfectly securing interventions on the antennas located at the ends of such masts.

Radio-amateur antenna masts are already known which are of the tilting type. In this regard, reference may in particular be made to US Pat. No. 4,167,740.

However, radio amateur antennas are a different technical field from that of cellular communication antennas.

PRESENTATION OF THE INVENTION

The invention proposes an antenna mast which makes it possible to meet this need. The solution proposed by the invention has the advantage of being particularly simple, of not requiring maintenance, of being suitable for outdoor installation and for weathering resistance.

Due to its simplicity, its intensive use does not induce abnormal wear

In addition, operators no longer need to climb to the top of the mast to work on the antennas, so that it is no longer necessary to provide steps or anchor points on the height of the mast and that the equipment that operators need is greatly simplified (absence of harnesses, lanyards, etc.) Furthermore, the absence of steps makes the mast well integrated into its environment

The solution proposed by the invention is a relay antenna mast (s) for cellular radio-telecommunications system, characterized in that it comprises - a mast base,

- at least one arm which is pivotally mounted on said mast foot and which carries at least one antenna,

- Means for locking said arm in a position in which the antenna (s) are in the high position, said arm being able, when the locking means are disengaged, to be tilted around its pivot axis up to a position where at least one antenna is at a height allowing intervention on it by an operator at the foot of the mast

Such a mast is also advantageously completed by the following different characteristics taken alone or in all their technically possible combinations

- According to a first variant, the arm extends on either side of its pivot axis and carries, on its branch opposite to that which carries the antenna (s), means forming a counterweight, - the means forming counterweights are adjustable in mass and / or in translation along the arm,

- According to another variant, it comprises an articulation with two elements fixed between on the one hand the mast foot and on the other hand the arm, one of these elements carrying means for fixing a retaining device allowing the operator to control the tilting of the arm;

- The retaining device is a removable device put in place by the operator before the disengagement of the locking means, then removed once the locking means have been re-engaged, after an intervention;

- The mast has several arms mounted pivoting on the same mast foot;

- one arm carries several antennas.

The invention further relates to a platform for relay antenna mast (s) of a cellular radio-telecommunications system in an urban environment comprising a relay antenna mast and a protective body guard, characterized in that the mast 'antenna (s) is a mast of the aforementioned type.

In particular, the antenna mast and the railing are advantageously carried by a building terrace.

Finally, the invention relates to the use of a tilting antenna mast to carry at least one relay antenna of a cellular radio-telecommunications system.

PRESENTATION OF THE FIGURES

Other characteristics and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting and which should be read with reference to the appended drawings in which:

- Figure 1 is a schematic representation in side view of a mast with adjustable counterweight arm according to a possible embodiment of the invention;

- Figure 2 is a schematic representation in top view of a structure capable of carrying six antennas and using the embodiment shown in Figure 1;

- Figures 3a to 3c are schematic representations illustrating the use of a mast of the type shown in Figure 1;

- Figures 4 and 5 are schematic representations in side view of masts according to another variant (variant with control joint), one on which the articulated arm is single and centered on its mast foot (Figure 4) , the other which has two articulated arms located on either side of the mast foot (Figure 5);

- Figure 6 is a top view representation of the structure of Figure 5;

- Figure 7 is a schematic representation of the foot of a mast of the type of those shown in Figures 4 to 6;

- Figure 8 details the use of an unwinder / rewinder in the variant of Figure 5; FIG. 9 is a schematic representation of a winder / unwinder device used with a structure of the type of that illustrated in FIGS. 5 to 8.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Counterweight antenna mast.

The antenna mast structure which is illustrated in FIGS. 1 and 2 comprises a foot 1 which extends vertically from a sole intended to be fixed on a platform P, which is for example a building terrace, by means of a metal stud, a slab or an equivalent support on which it is attached.

This antenna mast comprises at least one arm 3 which is pivotally mounted around a horizontal axis 4, at the end of the vertical foot 1 opposite the platform P.

This arm 3 extends on either side of the axis 4. One of these branches carries one or more relay antennas 5. The relay antenna (s) 5 are fixed to said arm 3 by connecting means 6 - known in themselves - which allow adjustment in Tilt and Azimuth.

An antenna descent 7a extends along the base of the mast. Such an antenna drop 7a is connected to an antenna 5 by a flexible coaxial strap 7b. The connectors - referenced by 7c - between the antenna drop

7a and the ramp 7b is at a height accessible by an operator on the platform P.

Due to its loop shape and flexibility, the coaxial strap 7b is able to follow the rotational movements of the arm without deteriorating.

As will be understood and as illustrated in FIG. 2, several arms 3 can be pivotally articulated around the same foot 1, each arm 3 being able, thanks to offset arms 5a, to carry several antennas 5. In In the example of FIG. 2, two arms 3 are mounted symmetrically on either side of the same foot 1. They each carry three antennas 5.

In the position of use (FIG. 3a), an arm 3 which carries one or more antennas 5 is locked relative to the foot 1 on which it is mounted, in a vertical position where it extends said foot 1.

Locking means are provided for this purpose constituted by a stirrup (not shown) which is passed over the arm (s) 3 and the vertical foot 1, a branch of said stirrup being introduced into a housing. complementary 9 provided on the foot 1 to receive it, said stirrup being then closed by means of studs / bolts type capable of being put in place on the ends of the legs of the stirrup.

Referring again to FIG. 1, it can be seen that an arm 3 carries, on the side opposite to the antenna (s) 5, means 8 forming a counterweight chosen so as to substantially balance the two branches that said arm 3 has on hand and other of axis 4.

The means 8 forming a counterweight can for example be constituted by lead plates threaded on a threaded rod, the number of plates and the position of the assembly along the arm being adjustable.

The balance provided by said counterweight means facilitates the tilting of an arm 3.

In particular, when an operator wishes to intervene on an antenna 5, it is sufficient for him to disengage the means which block said arm 3 in its vertical position relative to the foot 1 and if necessary to exert on the arm a slight torque tending to do so to toggle.

Since the two arms of the arm are substantially balanced, this tilting occurs very easily.

It is all the more easy to obtain if the counterweight is adjusted so that the torque which it exerts on the arm 3 is slightly less than that exerted by the antenna (s).

Once the means which ensure the blocking of the arm 3 in the vertical position disengaged, the tilting of the arm 3 occurs without the user having any effort to exert (tilting illustrated by the arrow F in FIG. 3b).

After the arm 3 has tilted, the antenna (s) 5 find themselves at a height which allows the operator to intervene on the antenna (s) in complete safety.

Furthermore, as illustrated in FIG. 3c, there is provided at the end of the arm 3 opposite the antenna (s) 5 a fixing means (hook for example) allowing a rope 10 to be hung. By pulling on this rope 10, the user rocks the arm 3 in the opposite direction to the initial tilting (arrow F2 in FIG. 3c) so that said arm 3 returns to its initial vertical position.

It then suffices for the user to replace the blocking means.

For example, the vertical foot 1 can be 3m high, while the arm 3 has a total length of 5m, i.e. 2.50m and 2.50m on either side of the articulation axis.

Antenna mast with control joint.

Other alternative embodiments of the invention will now be described with reference to Figures 4 and following.

In the antenna mast structure shown in these figures, the arm 3 carried by the vertical foot 1 extends substantially only on one side of its pivot axis 4.

To allow a user on the one hand to control the tilting of the arm 3 and on the other hand to replace it easily in its vertical position, there is provided a complementary articulation 13 and a retaining cable 14 that the user hooks to this joint to control the tilting of the arm.

More precisely, the articulation 13 comprises two elements 13a, 13b articulated in pivoting relation to one another, the element 13a being moreover articulated in pivoting on the arm 3, while the element 13b is articulated in pivoting on a stirrup 15 in the vicinity of the mast foot 1. As will be understood, the different pivot axes of these two elements 13a, 13b are parallel to the axis 4.

There is also provided on the element 13a, in the vicinity of its articulation on the element 13b, a loop 12 on which is fixed the retaining cable 14 (Figure 8). The cable 14 is passed over a pivoting roller 16 which is mounted on a stirrup which terminates the mast foot 1.

At its end opposite to the loop 12, the retaining cable 14 comprises means allowing the fixing of a unwinder / rewinder 19 (Figure 9) with which the user can control the tilting of the arm 3 and the ascent thereof.

Additional safety means making it possible to prevent a sudden tilting of the arm while the retaining cable is not in place are also provided. These security means remain permanently.

Thus, the intervention on such an articulated mast is done as follows.

The user disengages the locking means which maintain the arm in its vertical position where it extends the foot of the mast. The arm then tends on its own, under the effect of the force of gravity, to tilt in the positions illustrated in FIGS. 4 and 5.

The user controls this tilting by means of the unwinder 19 (FIG. 9).

It is also possible to provide end-of-travel stops preventing the articulated arm from descending below a given position.

The antennas 5 carried by the arm 3 that have been tilted are then found at a level allowing the user to intervene on said antennas in complete safety, a body guard with a height of the order of one meter at the level of the platform on which the antenna mast is mounted being sufficient (cf. collective protection bodyguard 17 in Figure 4).

When his intervention is finished, the user raises the arm 3 using his unwinder / rewinder 19 (Figure 9) and replaces the locking means when the vertical position is reached. Other retaining devices making it possible to soften the tilting of the arm and to facilitate its raising can be envisaged in place of a cable 14 (spring, hydraulic shock absorbers, jacks) or of the counterweight system.

Claims

1. Relay antenna mast (s) for cellular radio-telecommunications system, characterized in that it comprises:

- a mast foot (1),

- at least one arm (3) which is pivotally mounted on said mast foot (1) and which carries at least one antenna (5),

- means for locking said arm in a position in which the antenna (s) are in the high position, said arm (3) being able, when the locking means are disengaged, to be tilted about its pivot axis ( 4) to a position where at least one antenna is at a height allowing intervention on it by an operator at the foot of the mast.

2. Mast according to claim 1, characterized in that the arm (3) extends on either side of its pivot axis (4) and carries, on its branch opposite to that which carries the antenna (s) ( s), (8) forming a counterweight.

3. Mast according to claim 2, characterized in that the means (8) forming a counterweight are adjustable in mass and / or in translation along the arm.

4. Mast according to claim 1, characterized in that it comprises an articulation with two elements (13a, 13b) fixed between on the one hand the mast foot (1) and on the other hand the arm, one ( 13a) of these elements carrying means (12) for fixing a retaining device (14) allowing the operator to control the tilting of the arm.

5. Mast according to claim 4, characterized in that the retaining device (14) is a removable device put in place by the operator before the disengagement of the blocking means, then removed once the blocking means have been re-engaged , after an intervention.

6. Mast according to one of the preceding claims, characterized in that it comprises several arms (13a, 13b) pivotally mounted on the same mast foot.

7. Mast according to one of the preceding claims, characterized in that an arm carries several antennas.

8. Platform for relay mast (s) of cellular radio-telecommunications system in an urban environment comprising a relay antenna mast and a protective body guard, characterized in that the antenna mast (s) is a mast according to one of the preceding claims.

9. Platform according to claim 8, characterized in that the antenna mast and the bodyguard are carried by a building terrace.

10. Use of a tilting antenna mast to carry at least one relay antenna of a cellular radio-telecommunications system.