EP0114377B1 - Method of operating a telescopic mast, as well as a mast suitable for carrying out the method - Google Patents

Abstract

1. A process of operating a telescopic mast - in particular an aerial mast - extension of which is caused by means of incoming compressed air at a pre-adjustable end pressure in plenum chambers variable in capacity, and retraction of which into the initial position or into intermediate positions is permitted by the adjustable passage cross-section at an adjustable speed of the feed valve separate from the compressed air supply, characterized by the following features : a) that the compressed air via valves (I.1, I.2, I.3) is passed in parallel or in an independent and adjustable order of sequence into the plenum chambers (I, II, III...) respectively composed of at least two nested telescopic tubes (Ib/Ic, IIb/IIc, IIIb/IIIc), b) that piston (IIa/IIIa) respectively closing at the bottom of the follow-up chamber (Ib, IIb, IIb) and the closure lid of the end telescope tube (IIIc) respectively draws apart the individual telescopic structures of the plenum chambers (I, II, III...) respectively disposed therebelow, c) that the pressure the individual superposed plenum chambers (I, II, III...) is adjusted from bottom to top - dropping stepwise, d) that the minimun level of the individual pressure steps is respectively determined by the residual weight of the plenum chambers (I, II, III...) respectively formed by the telescopic structures associated to one another, piston rings and back stops with mast (1) in the extended position, and (e) that the retraction of mast (1) into the initial position or into intermediate positions is effected by opening or by opening and closing, respectively, of the valves (I.1, I.2, I.3) associated to the individual plenum chambers (I, II, III...).

Description

The invention relates to a method for operating a telescopic mast - in particular an antenna mast = whose extension stroke is brought about by inflowing compressed air at a presettable final pressure in volume chambers whose content can be changed, and whose return stroke to the starting position or in intermediate positions through the adjustable passage cross-section with adjustable speed of the Compressed air supply separate feed valve is possible, as well as an appropriate design of the mast to carry out the operating process.

The German utility model 7629017 has made a pneumatic, adjustable mast known, the trains of which are formed from two telescopic tubes and are each closed at the bottom by an open piston equipped with air ducts.

The air ducts through the individual pistons form interchangeable orifices of different cross-sections, through which the time sequence of the lifting and lowering movements can be influenced.

By appropriate dimensioning, the mast levels can be at about the same time, d. H. can be extended or retracted in a continuous relationship to one another or step by step with short, accelerated path overshoots.

Another tower which can also be brought pneumatically into its end position is identified by US Pat. No. 2,849,011.

This document calls an inflatable bellows, made of flexible, airtight material, which carries a headlight platform in its end position.

Apart from the instability of this non-metallic hollow body despite the tension, the non-existent telescopic design prevents the otherwise possible adjustments of intermediate positions and, due to the material, is easily vulnerable.

Furthermore, US-A 2 369 534 describes a mast which is pulled up in sections by means of two lifting columns arranged axially parallel to it on a base plate, over the hooks associated with each section with hanging gear, by means of ropes guided over rollers and anchored in the end position.

The mast does not correspond to the concept described at the beginning and cannot be regarded as a mobile, operational antenna mast.

In summary, the state of the art shown here is that basically only the antenna mast designed according to the above-mentioned utility model specification 7629017 and the method for mast control which can also be found in this specification must be examined in more detail.

The uninterrupted air flow within the telescopic mast to the top of the mast must be regarded as the main disturbing factor.

The inevitable leaks between the individual telescopic hoists are the reason for the air replenishment, which can often be repeated even at relatively high internal overpressure, with premature wear of the guides, especially with changing wind loads.

Furthermore, it must be considered a disadvantage that the setting of intermediate heights - due to the uniform, continuous air column - is unstable, and even the slightest injuries to a guide, especially the connecting end bushing between two telescopic tubes, lead to a practically complete failure of the device can.

The absorption of the total pressure from the mast, which is based on the airtight closure of a supply line, must also be regarded as a risk.

Taking this situation into account, it is the object of this invention to name an operating method for the operation of pneumatically controlled telescopic masts of the type described at the outset, which better stabilizes the stresses on the bearings of the telescopic hoists and the mast even at different height settings and often changing strong wind loads and the risk posed by at least reduces the required absorption of the total pressure by closing the feed line.

In addition, a mast design that is particularly suitable for carrying out the operating method must be described.

The solution to this problem according to the invention provides that the compressed air is passed in parallel or in an independent, adjustable order into the volume chambers, each consisting of at least two telescopic tubes that are guided one inside the other, via valves, that the piston of the following chamber, or the end cover of the end telescopic tube, closes the individual Telescopic pulls of the volume chambers arranged below each other pulls apart so that the pressure in the individual volume chambers arranged one above the other is adjusted from bottom to top, falling in stages, so that the minimum height of the individual pressure stages is determined in each case by the residual weight of the telescopic cables which are assigned to each other, Piston rings and limit stops each formed volume chambers are determined when the mast is in the extended position, and that the return stroke of the mast into the starting position or in intermediate positions by opening or opening and closing the individual valves assigned to volume chambers. The setting of Intermediate positions are particularly important for the uppermost volume chamber, since it facilitates the alignment of the antenna.

The independent feeding of the compressed air into the individual volume chambers in an adjustable order ensures that the entire mast does not collapse suddenly in the event of leaks in the individual telescopic cables or in the event of valve damage, but that the damage remains restricted to only one chamber and is temporarily caused by additional feeding in a chamber is usually taken into account and can be repaired on a case-by-case basis. This applies in particular to bullet damage.

In this context - as not essential to the invention - it is recommended, for example, to provide a quick shut-off valve in front of each feed valve, so that a valve replacement or a seal change that becomes necessary can be quickly avoided without any difficulty.

Extending the mast according to the pull-out method described reduces the demands on the guidance of the telescopic parts into one another, since any tilting effects, for example due to wind load, are compensated for more easily in pulling operation than in printing operation.

. Basically, there is nothing more to be said about the pressure in the individual chambers that falls in stages, whereby the level of the pressure levels to be maintained is of course generally exceeded for safety reasons.

The adjustment of the mast height in intermediate stages is possible without restriction in practice; reference is made to the preliminary remark. In addition, it is additionally proposed that the volume chambers be extended one after the other from bottom to top, and after the end of a single hoist - before initiating the next hoist - the end position corresponding to the stop limits is secured by bracing to the installation level.

In this way, the mast is secured against the effects of wind power and each volume chamber is statically clearly fixed in its extended position.

A mast training which is particularly suitable for carrying out this operating method assumes that the separate air supply and execution into or from the individual chambers takes place via valves which open via feed lines in the foot part or in the region thereof.

Taking this into account, it is provided that for the supply of the compressed air - viewed from the foot part - for the second and each downstream volume chamber formed by telescopic cables connected within this chamber against the upstream volume chamber (s) sealing lines are provided, the stretch dimension at least corresponds to the dimension of the lifting height of the first volume chamber or the sum of the lifting heights of the overall upstream volume chambers.

The stretchable lines can be, for example, folded pressure hoses.

In a modification of the distribution, which is exclusively internal to the mast, it can be provided that the stretchable lines required for supplying the compressed air to the volume chambers are arranged outside the volume chambers underneath.

Furthermore, it is provided that the stretchable lines are coiled or zigzag-shaped hose or elastic pipes, which have the characteristic of a tension spring.

Of course, the stretchable lines can each be hose lines of sufficient stretching length, which can be arranged in any way within each chamber.

Instead of hose lines, it can also be provided that the stretchable lines are separate telescopic cables formed from pipes, each with a sufficient stretching length.

As a further protection against bending or kinking it is provided that at the last telescopic pull forming the top of the mast the end volume. Menkammer, axially parallel to this, at least three cantilever arms are articulated, which by about. 90 ° to the mast axis, can be folded out due to the heavy weight, and that the articulation ends of these cantilever arms, the cable articulation at the mast tip and the cable articulation in the foot area of the mast are connected by tensioning devices.

Regardless of this, it must be mentioned that the individual telescopic cables are mutually designed, secured against rotation, and that the mast is preferably made of light metal telescopic cables in the interest of high mobility.

• Figur 1 rechts zeigt im Halbschnitt einen ausgefahrenen, aus drei, jeweils zweiteiligen zylindrischen Teleskoprohren zusammengesetzten Volumenkammern gebildeten Mast einschließlich einer zusätzlichen mastinternen Sicherung der Mastspitze zum Mastfuß.
• Figur 1 links zeigt ebenfalls im Halbschnitt den Mast in zusammengefahrener Stellung.
• Figur 2 zeigt eine Draufsicht bzw. einen partiellen Schnitt auf bzw. durch das Fußteil des Mastes mit innenliegenden Speiseleitungen für drei Volumenkammern (durch Fig. 1).

The operating method according to the invention is explained in more detail with the aid of the attached exemplary systematic representation of an antenna mast.

• Figure 1 on the right shows a half section of an extended mast formed from three, two-part cylindrical telescopic tubes composed of volume chambers including an additional internal mast securing the mast tip to the mast base.
• Figure 1 on the left also shows a half section of the mast in the retracted position.
• FIG. 2 shows a top view or a partial section on or through the foot part of the mast with internal feed lines for three volume chambers (through FIG. 1).

The mast 1 consists of the mast members 2.1, 2.2 and 2.3, these corresponding to the volume chambers I, 11 and 111 formed from two telescopic tubes Ib / lc, Ilb / llc, Illb / lllc.

The telescopic tube Ib is closed at the bottom by the foot part la and its height by the inward direction impact limit le determined, the through opening corresponding to the diameter of the telescopic tube Ic through the stop limit le.

The bushings from the subsequent limit stops If, IIe and Ilf are designed accordingly.

In the telescopic tube Ic, the piston IIa carrying the telescopic tube IIb is displaceably arranged and the height of the telescopic tube Ilb is determined by the stop limitation Ile.

In the telescopic tube Ilb, the telescopic tube Ilc is delimited and guided at the bottom, while the length of the telescopic tube Ilc is determined by the limit stop Ilf. The telescopic tube IIc is guided by the piston ring Ild.

In the telescopic tube IIc, the telescopic tube IIIb is displaceably guided by the piston Illa, the length of which is determined by the limit stop Ille.

In the telescopic tube IIIb, the telescopic tube IIIc is guided through the piston ring IIId, this tube forming the mast tip to which a cable link 3.2 is attached.

The air supply to the three mast sections 2.1, 2.2 and 2.3, which in turn form the volume chambers I, II and 111, takes place via the valves 1.1, 1.2 and 1.3 and via the feed lines 1.1.1, 1.2.1 and 1.3 introduced in the base part la. 1 to the individual volume chambers, the volume chamber I being fed through valve 1.1 and supply line 1.1.1 and pulling it out.

The volume chamber II is fed and pulled apart by the valve 1.2 and the feed line 1.2.1 via the hose coil 11.2 and the open passage IIg arranged in the piston Ila.

Another hose coil III.3, which is connected via the valve 1.3 and via the supply line 1.3.1 of the air supply, leads through the closed, further passage IIh through the volume chamber II and through the passage IIIg arranged in the lilac and causes the shipment thereof Volume chamber III formed from IIIb and IIIc into its end position.

The mast links 2.1, 2.2 and 2.3, d. H. The volume chambers I, II and III are extended one after the other, whereby in the end position of each mast link 2.1, 2.2 and 2.3, before pulling out the next telescopic hoist, the end position is braced with the flat surface by means of ropes or chains using ropes or chains 2.11, 2.21 and 2.31 will.

Regardless of this security system, an internal mast tensioning system is also provided. In this case, the last telescopic tube IIIc, in the case of this example, is connected to three fold-out cantilevers 3.1 provided with rope linkages, and between these, the rope linkage at the mast tip 3.2 and the rope linkages at the mast base 3.3, tensioning mechanisms 3 are formed.

By means of these tensioning mechanisms 3, the mast 1 is tensioned in itself, essentially axially directed, regardless of its fixation to the formation.

As far as the function is concerned, it should also be noted that the volume chambers I, II and III forming the individual mast members 2.1, 2.2 and 2.3 can be actuated independently, but as a rule the individual volume chambers are extended one after the other from bottom to top and in their respective end positions are secured to the formation by means of guy lines 2.11, 2.21 and 2.31.

The pressure in the individual volume chambers I, II and III is set to decrease in stages from bottom to top, the minimum height of the pressure stages being determined in each case by the residual weight of the downstream telescopic cables.

Claims (10)

1. A process of operating a telescopic mast - in particular an aerial mast - extension of which is caused by means of incoming compressed air at a pre-adjustable end pressure in plenum chambers variable in capacity, and retraction of which into the initial position or into intermediate positions is permitted by the adjustable passage cross-section at an adjustable speed of the feed valve separate from the compressed air supply, characterized by the following features :

a) that the compressed air via valves (L1, 1.2, 1.3) is passed in parallel or in an independent and adjustable order of sequence into the plenum chambers (I, II, III...) respectively composed of at least two nested telescopic tubes (Ib/Ic, Ilb/llc, lllb/lllc),

b) that piston (IIa/IIIa) respectively closing at the bottom of the follow-up chamber (Ib, lib, IIIb). and the closure lid of the end telescope tube (Illc), respectively draws apart the individual telescopic structures of the plenum chambers (I, II, III...) respectively disposed therebelow,

c) that the pressure within the individual superposed plenum chambers (I, II, III...) is adjusted from bottom to top - dropping stepwise,

d) that the minimum level of the individual pressure steps is respectively determined by the residual weight of the plenum chambers (I, II, III...) respectively formed by the telescopic structures associated to one another, piston rings and back stops with mast (1) in the extended position, and

e) that the retraction of mast (1) into the initial position or into intermediate positions is effected by opening or by opening and closing, respectively, of the valves (1.1, 1.2, 1.3) associated to the individual plenum chambers (I, II, III...).

2. A process according to claim 1, characterized in that the plenum chambers (I, II, III...) successively extended from bottom to top, upon completion of respectively one single stroke - prior to initiating the next stroke - are fixed in their end position respectively corresponding to the back stops (If, llf, Ille), by aerial supports (2.11, 2.21, 2.31), relative to the plane of erection.

3. A construction of the mast for carrying into effect the operating process according to claim 1, characterized in that provided for the supply of compressed air - viewed from the base portion (la) - to the second and any follow-up plenum chamber (I, II, III...) coherently formed by telescopic structures (Ib/lc, IIb/IIc, IIIb/IIIc...) are lines (11.2, 111.3) within the said chambers, that are sealed against the plenum chamber(s) disposed upstream thereof, with the amount of extension of the said lines at least corresponding to the amount of the stroke level of the first plenum chamber or to. the sum of the stroke levels of the total number of plenum chambers disposed upstream, respectively.

4. A construction according to claim 3, characterized in that the extensible conduits required for the supply of compressed air to the plenum chambers are disposed externally of the plenum chambers disposed therebelow.

5. A construction according to claims 3 and 4, characterized in that the extensible conduits (11.2, 111.3...) constitute helically or zigzag-shaped hoses or flexible tubular lines having approximately the characteristic of a compression spring.

6. The construction according to claims 3 and 4, characterized in that the extensible conduits (11.2, 111.3) constitute hoses having a respectively adequate extensible length.

7. The construction according to claims 3 and 4, characterized in that the extensible conduits (11.2, III.3) are separate tubular telescopic structures of a respectively adequate extensible length.

8. A construction of the mast for carrying into effect the operating process according to claims 1 and 2, characterized in

that pivoted to the last telescopic structure (IIIb, IIIc) of the end plenum chamber, forming the tip of the mast (1), in a manner axially parallel thereto, are at least three cantilevers (3, 1) which, in the extended position of the said telescopic structure (Illb, IIIc) - directed by a maximum amount of about 90° - are foldable in response to gravity, and

that the pivot ends of the said cantilevers (3.1), the cable coupling at the mast tip (3.2) and the cable couplings (3.3) in the base area of the mast (1) are interconnected by clamping mechanisms (3).

9. The construction according to claim 3, characterized in that the individual telescopic structures (Ib/Ic, IIb/IIc, Illb/lllc) are secured against torsion with respect to one another.

10. The construction according to claim 3, characterized in that the telescopic structures (Ib/Ic, IIb/IIc, Illb/lllc) are made of metal, preferably of light metal.

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