EP1321426A1 - Telescopic boom - Google Patents

Abstract

The outrigger has a second hydraulic cylinder-piston system (8) in parallel with the first one (7), also with both its axial ends fixed in the base box (2) and with its extendable part connectable by the second of two coupling devices (12, 15) to the inner boxes (3, 4, 5, 6) to be extended. The two cylinder-piston systems can be operated in opposition to each other.

Description

The invention relates to a telescopic boom, in particular a telescopic boom for a mobile crane with the features mentioned in the preamble of claim 1.

Telescopic booms with hydraulic telescopic systems have been around for many years known. DE 198 24 672 A1 describes a crane with a telescopic boom described. The telescopic boom has a basic box in which several Inner boxes are essentially coaxially guided. The inner boxes can one by one through a hydraulic cylinder / piston system be extended. The hydraulic cylinder / piston system is one its two axial ends (foot area) fixed in the basic box and with his extendable part by means of a coupling device to the one to be moved Inner box connectable. This coupling device is also used as a backup and Locking unit called. The extendable part of the cylinder / piston system can either in the piston rod or in the hydraulic cylinder. The inner boxes can each in their retracted and in their extended position by one of opposite the locking and actuating bolting device the next larger inner box or (in the case of the outermost inner box) with the Basic box of the telescopic boom can be mechanically locked so that none relative shift against each other is more possible. Immediately before the procedure an inner box is the bolting device after coupling the Locking and locking unit unlockable by the latter. The extension length of the hydraulic cylinder / piston system corresponds in this known solution to the axial length of the longest inner box to be moved. In the extended Position, the length of the hydraulic cylinder / piston system is practically double so long. Since the extension of telescopic shots has to take place partly under load, there is a particular problem regarding the buckling stiffness of the cylinder / piston system. This has a comparatively massive design with a corresponding weight of this system. The lowest possible weight for that Telescopic system is desirable, however, so that e.g. because of the limitation of permissible axle loads of a mobile crane, the highest possible weight proportion for the Telescopic shots of the telescopic boom remain available to the largest possible To be able to implement extension length. Compared to so-called fully hydraulic Telescopic systems that have an extremely heavy hydraulic cylinder / piston system have as a drive, the time required for extending this telescopic boom the inner boxes about twice as high because the extension movement is not fully continuous but after every working stroke with which an inner box is extended the cylinder / piston system is initially an idle stroke in the sense of a Return movement to the starting position must be carried out to the next To be able to grip the inner box.

DE 198 24 671 A1 describes a largely similar telescopic boom known, which is essentially different from the telescopic boom described above distinguishes that the hydraulic cylinder / piston system used for telescoping has a length that is only about half the length of the longest extendable inner box corresponds. In this solution, the piston rod is the Cylinder / piston system articulated in the foot area of the basic box, so that the Cylinder forms the extendable part of the cylinder / piston system. The cylinder is in in this case equipped with two security and locking units, one of which one is at the top and the other at the bottom axial end of the cylinder. In contrast to this, the individual inner boxes are telescoped Telescopic boom according to DE 198 24 672 A1 with this solution not in one Step, but in two steps. The lower one is used to extend Security and locking unit operated and the respective inner box to about extended half its extension length and locked in this intermediate position. The cylinder then moves back to its starting position. Once this is reached, the upper locking and locking unit is in one Position that approximately corresponds to the position of the lower locking and locking unit on Corresponds to the end of the first step. The second backup and Locking unit is back to start position with the lower fuse and Locking unit to grip the next inner box. The time required for that Extending an inner box is almost the same size with this telescopic boom in the telescopic boom according to DE 198 24 672 A1. The advantage of this solution is but to see that the length of the hydraulic cylinder / piston system halves is and therefore for the entire hydraulic cylinder / piston system also as a result of Gain in buckling rigidity due to the shortened overall length (possibility of Cross-sectional reduction) a drastic weight reduction is achieved.

A similar solution with a hydraulic cylinder / piston system with an axial Length which corresponds to approximately half the axial length of an inner box to be extended, is known from EP 1 072 554 A1. There comes only one backup and Locking unit for use. However, this is designed so that it can be solved with the cylinder of the hydraulic cylinder / piston system is connected. That is it possible to secure and lock the unit at the end of the first partial stroke Leave extension movement for an inner box in the position reached, from Uncouple the cylinder, then the cylinder to its original position drive back and then the locking and locking unit to the top of the retracted cylinder to couple again to the second partial stroke of the Realize extension movement. This solution brings savings in terms the number of security and locking units to be provided, but required an additional effort for the releasable coupling of the only fuse and Locking unit on the cylinder. With regard to the need for an empty stroke and thus on the extension of the extension movement of the inner boxes no differences compared to the solution according to DE 198 24 671 A1.

The object of the present invention is to provide a telescopic boom Generic type to further develop in such a way that the lowest possible Weight for the drive system the time for an inner box to be extended into its maximum extended position is significantly shortened.

This task is solved on the basis of a telescopic boom with the The preamble of claim 1 features mentioned by the characterizing Features of patent claim 1. Advantageous further developments of the invention result itself from the subclaims.

The present invention is based on a telescopic boom, which is particularly for Mobile cranes is provided and has a basic box in which one or more Inner boxes are essentially coaxially guided. These inner boxes are one by one by a first hydraulic cylinder / piston system extendable, this hydraulic cylinder / piston system on one of its two axial ends (foot area, i.e. lower in the working position of the telescopic boom End) is fixed in the basic box and with its extendable part by means of a preferably designed as a securing and locking unit first Coupling device can be coupled to the inner box to be moved in each case. The respective inner box is in its retracted and in its extended position each by e.g. operated by the locking and locking unit Bolting device compared to the next larger inner box or the Basic box (preferably mechanically) lockable so that none Relative displacement between the inner boxes or the basic box more take place can. Immediately before moving an inner box is after the Coupling device (securing and locking unit) has the respective Inner box can be unlocked using the locking and locking unit. To the To reduce the time required for extending the inner boxes, the invention provides that parallel to the first hydraulic cylinder / piston system, a second hydraulic one Cylinder / piston system is arranged, which also with one of its two axial ends is fixed in the basic box and with its extendable part by means of a second, e.g. coupling device designed as a safety and locking unit can be coupled to the inner box to be moved in each case. It is also provided that that the two cylinder / piston systems can be operated in opposite directions. This is it possible that during the execution of an idle stroke in which the one hydraulic Cylinder / piston system returns to its original position with the help of another hydraulic cylinder / piston system already a further extension movement to execute for an inner box. This can result in an almost continuous Telescopic movement for the boom can be achieved without the heavy weight of one Drive system for a conventional fully continuous telescopic operation in purchase to have to take.

It is particularly advantageous if the control of the hydraulic cylinder / piston systems and the coupling points for the security and locking units in the inner boxes of the telescopic boom are designed so that the two Cylinder / piston systems can be coupled to the same inner box at the same time. This significantly improves the possible use of the respective telescopic crane, because in such a case with a correspondingly drastically increased telescopic force can be worked. So there is an extremely powerful telescopic system available Available. However, this way of working must then be done with the night part Extension of the telescoping times can be bought as necessary Return movements of the cylinder / piston systems to their starting position no working stroke can take place simultaneously.

Basically, it is possible to use two parallel cylinder / piston systems, their Length in the retracted state practically over the length of the package retracted telescopic shots. This solution is compared to one fully hydraulic telescopic system still gives weight savings, however As a rule, however, compared to the one-cylinder solution according to DE 198 24 672 A1 a weight increase can be accepted. In contrast to this known solution, a drastic reduction in telescoping times and achieve weight reduction when according to a preferred embodiment the extendable length of the two cylinder / piston systems of the present invention each chosen significantly smaller than the extendable length of the respective inner box and the respective inner box by means of the first hydraulic cylinder / piston system from the retracted position over a first section of the entire extendable length of the inner box and by means of the second hydraulic Cylinder / piston system over a second section of the entire extendable length the inner box can be moved into its end position. Preferably, the extendable length of the two cylinder / piston systems in the range of about 40% - 60%, especially at about 50% of the largest extendable length of an inner box.

When using shortened cylinder / piston systems, their extendable length is less than the largest extendable length of an inner box, it is provided that in the retracted state on the one cylinder / piston system, e.g. as Securing and locking unit trained coupling device based on the Position of the telescopic boom at work on the lower axial end (foot area) and e.g. also designed as a security and locking unit Coupling device of the other cylinder / piston system at its upper axial end (Head area) is arranged. This makes it possible that the respective inner box from the retracted position by the lower locking and locking unit gripped, moved to the respective intermediate position after unlocking and there is discontinued and locked. If the lower locking and locking unit drives back, the upper locking and locking unit in the coupling point intervene, release the lock again and insert the inner box into the desired one Move to the end position and place it there, i.e. again with the next largest Lock the inner box or the outermost inner box with the basic box. However, provision can also be made for locking in the intermediate position waive if for the upper and lower locking and locking unit separate coupling points are provided. In this case, however be sure that the lower locking and locking unit only from can decouple the respective inner box if the upper fuse and Locking unit has already been coupled and the lock in the unlocked Holds position. This can be done by controlling the hydraulic system, preferably a Digital control.

In another advantageous embodiment, the invention provides that both Cylinder / piston systems each as coupling devices via two safety and Locking units have, one in the foot area and the other in Head area of the respective cylinder / piston system (based on the retracted Position) is arranged. This makes it possible, except for the invention Counter-clockwise operation of the cylinder / piston systems even when using shortened ones Cylinder / piston systems, if necessary, temporarily in synchronous operation and therefore with to work accordingly increased telescopic force. In counter-clockwise operation then the previously described mode of operation takes place, in each case during the Working strokes of a cylinder / piston system over the intended section of the total extension length of the respective inner box, the idle stroke of the other Cylinder / piston system is executed to largely eliminate dead times. In the The respective inner box becomes synchronous after both have intervened in the foot area arranged locking and locking units, for example, to about 50% of the Telescopic box length. Then both cylinder / piston systems retract their starting position back and leave their upper safety and Couple locking units and move the inner box into each desired basic position, for example at 90% or 100% of the maximum Extension length is. Of course, the inner box remains in during the empty lift locked its intermediate position.

Instead of equipping both cylinder / piston systems, each with two safety and Locking units can also be provided in a known manner, each Cylinder / piston system with only one locking and locking unit to be provided, but which is displaceable in the axial direction and on the two axial ends of the respective cylinder / piston system (based on the retracted Position) can be locked. The above-described effect can thus be used in the same way achieve, as is the case with the shortened one-cylinder system according to DE 198 24 671 A1 has already been explained at the beginning.

In a further advantageous embodiment, the invention provides that the two Cylinder / piston systems have different diameters, i.e. on different hydraulic power are designed. Basically, the two can Cylinder / piston systems can be arranged horizontally next to each other, but in Generally the profile cross sections of telescopic booms in the vertical direction (height) are larger than in the horizontal direction (width), it is recommended to use the two Arrange cylinder / piston systems one above the other, preferably the cylinder / piston system with the smaller diameter over the cylinder / piston system with the larger diameter. To reduce the deflection in particular When extended, it is also recommended to use the two cylinder / piston systems to support each other via slide rails.

It can be provided that the cylinder / piston systems each with their cylinder in the Base box to fix and the piston rod as a moving part of the cylinder / piston system to let work. This brings advantages with regard to the attachment of the Supply lines for the pressure medium supply to the hydraulic cylinders. The reverse Arrangement is of course also possible and has advantages in other respects. On a movable hydraulic cylinder can namely in their head and The required securing and locking units if necessary be attached. An arrangement in which the one cylinder / piston system with its hydraulic cylinder and the other Cylinder / piston system is fixed with its piston rod in the basic box. But it is also possible with a cylinder / piston system with a cylinder fixed to the basic box a locking and locking unit in the foot area of the cylinder / piston system to couple with the extendable piston rod. A pull frame can be used for this be connected to the free end of the piston rod and parallel to Longitudinal axis extends to the foot area of the cylinder / piston system. In this case is spoken of a train frame construction.

An advantageous embodiment of the invention provides that the two Cylinder / piston systems are each designed for different telescopic forces. This can be implemented in such a way that the first cylinder / piston system unites has a smaller diameter than the second cylinder / piston system and with its Cylinder fixed in the basic box and with regard to its only safety and Locking unit is designed in a pull frame design and that the second Cylinder / piston system with its piston rod fixed in the basic box and its only one Locking and locking unit at the upper end of its extendable cylinder is attached. The first cylinder / piston system therefore takes over the first Partial step of the extension movement for an inner box. This is generally requires significantly less hydraulic power than for the second sub-step Extension movement. Therefore, the smaller cylinder / piston system for the first and the larger one is used for the second step.

Fig. 1 einen axialen Querschnitt durch einen Innenkasten mit übereinander angeordneten Zylinder/Kolben-Systemen,

Fig. 2 einen axialen Querschnitt durch einen Innenkasten mit horizontal nebeneinander angeordneten Zylinder/Kolben-Systemen,

Fig. 3 eine längsgeschnittene Ansicht eines erfindungsgemäßen Teleskopauslegers mit zwei verkürzten Zylinder/Kolben-Systemen in zwei unterschiedlichen Ausfahrstellungen,

Fig. 4 einen Querschnitt durch zwei ineinander geführte Innenkästen des Teleskopauslegers gemäß Fig. 3 und

Fig. 5 Längsschnitte durch einen erfindungsgemäßen Teleskopausleger mit jeweils zwei Sicherungs- und Verriegelungseinheiten an seinen beiden Zylinder/Kolben-Systemen in drei unterschiedlichen Arbeitsstellungen während des Verfahrens eines Innenkastens.

The invention is described in more detail below with reference to the exemplary embodiments shown in schematic form in the figures. Show it:

1 shows an axial cross section through an inner box with cylinder / piston systems arranged one above the other,

2 shows an axial cross section through an inner box with horizontally adjacent cylinder / piston systems,

3 is a longitudinal sectional view of a telescopic boom according to the invention with two shortened cylinder / piston systems in two different extended positions,

Fig. 4 shows a cross section through two interlocking inner boxes of the telescopic boom according to Fig. 3 and

Fig. 5 longitudinal sections through a telescopic boom according to the invention, each with two locking and locking units on its two cylinder / piston systems in three different working positions during the movement of an inner box.

Components with the same function have been given the same reference symbols in the figures Mistake. The cross section shown schematically in Fig. 1 by a Inner box 3 of a telescopic boom, which is otherwise not shown in more detail in two hydraulic cylinder / piston systems arranged vertically one above the other 7, 8, each with a locking and locking unit 12, 15 are equipped. It can also be seen that the securing and locking units 12, 15 by means of coupling elements 20 and 21, respectively, which are installed in the inner box 23 3 can intervene, can couple to the inner box 3, so that this in the direction the longitudinal axis of the inner box by the cylinder / piston systems 7, 8 displaceable is. The cylinder / piston systems 7, 8 are guided by a guide 32. With With the help of locking bolts 22, each in corresponding locking openings in a next larger inner box or in the basic box, which is not shown in Fig. 1 intervene, the inner box 3 can be locked accordingly. By appropriate means of intervention can the respective security and Locking device 12, 15 unlock the locking bolt 22 in order to move to allow the inner box 3.

2 is a cross-sectional representation through an inner box, which is basically the same 3 reproduced, in which, in contrast to Fig. 1, it is only provided that the two cylinder / piston systems 7, 8 are arranged horizontally next to each other. In the position of the locking bolts 22, which is shown in FIG engage the top and bottom of the profile rotated by 90 °, so that an engagement in the both side walls of the profile. For connecting the fuse and Locking units 7, 8 are in each case only one coupling element 20 intended.

From FIG. 4, which has an axial cross section through two inner boxes 3, 4 of FIG. 3 in Representing the shape of two longitudinal sections shown telescopic boom 1 are further Details recognizable. It can be seen that the inner box 3 via slide bearings 28, 29, with Lubricant feeds are provided, sliding against the next largest Inner box 4 is supported. Of the two securing and locking units 12, 15, only the coupling elements 20, 21 can be seen, which are connected to one another in pairs are arranged opposite each other. These bolt-shaped coupling elements 20, 21 can engage in corresponding coupling openings 24 and 25, which are in lateral partition-like internals 23 are located. The actuation of the coupling elements 20, 21, which is not shown here, can for example be mechanical, electrical, pneumatic or hydraulically. Locking bolts are just as little in this cut as the devices for actuating the locking bolt shown. But you can see that the two Zyllnder / piston systems 7, 8 on each other and slide rails 26, 27 are supported against the inner box 3.

3, which are guided by a telescopic boom 1, show the innermost inner box 3 in an approximately half extended intermediate position (upper illustration) or in the fully extended end position (lower illustration). The Telescopic boom 1 has a basic box 2, which is at its foot end Has pivot bearing 18 with which the telescopic boom 1 around a horizontal Swivel axis is rockable. The rocking movement is by means of a not shown hydraulic rocker cylinder executed on the superstructure, not shown a mobile crane can be stored and with its extendable part in a warehouse 19 can be articulated on the underside of the basic box 2. The telescopic boom 1 has, in addition to the inner box 3, three other inner boxes 4, 5, 6, which in corresponding to how the inner box 3 telescopic and by reversing the Work processes can be telescoped in a corresponding manner. It can also be seen that the two cylinder / piston systems 7, 8 parallel to the longitudinal axis of the Telescopic boom 1 are arranged. As more clearly from the sectional view of FIG. 4 emerges, the upper cylinder / piston system 7 has a somewhat smaller one Diameter on than the lower cylinder / piston system 8, so that the former at the same Hydraulic pressure developed a correspondingly lower hydraulic force. The Cylinder / piston system 7 is with its cylinder 9 via a mounting 16 at the foot of the Basic box 2 stored in this stationary. The piston rod 10 of the cylinder / piston system 7 is fully extended in the upper part of FIG. 3. she wears at its free (left) end a pull frame 11, which is towards the foot end of the boom 1 extends and at its lower (right) end the fuse and Locking unit 12 carries, with which the cylinder / piston system 7 to the inner box 3 is coupled. The lower end of the inner box 3 is therefore in the area of Securing and locking unit 12. Seen at the same height in the axial direction there is also the locking and locking unit 15 of the second Cylinder / piston system 8, the cylinder with 13 and the piston rod with 14 is designated. This cylinder / piston system 8 is with the lower end of the Piston rod 10 fixed by means of a fastening 17 at the base of the base box 2, so that the cylinder 13 represents the extendable part of this cylinder / piston system 8. At the upper (left) end of the cylinder 13 is the second locking and locking unit 15 attached. In the position shown in the illustration above, the Inner box 3 through the locking and locking unit 15 to the other Security and locking unit 12 are passed, so that another Extension of the inner box 3 by means of the second hydraulic cylinder / piston system 8 is possible. 3 shows the final state for this Extend process again, in which the inner box 3, which is still connected to the fuse and Locking unit 15 is coupled, is in its end position. During the Movement of the locking and locking unit 15 from the position in the upper Representation in the position of the lower representation is the uncoupled first backup and Locking unit 12 of the cylinder / piston system 7 back into the Retracted starting position, more specifically to a position where the Securing and locking unit 12 in the foot area to the next largest Can couple inner box 4. Following the situation according to the below 3, the extension of the is no longer shown Inner box 4 with its first sub-step, while at the same time the second backup and Locking unit 15 uncouples from the fully extended inner box 3 and moves back into a position suitable for taking over the inner box 4, which corresponds to the conditions in the upper representation of FIG. 3. In this way All inner boxes 3 - 6 can be extended one after the other to a desired extension length extend, the extension movement only by extremely small dead times during the transfer of an inner box 3 - 6 between the two fuse and Locking units 7, 8 is interrupted. This is possible, although the two Cylinder / piston systems in the illustrated embodiment in the retracted state only have a length that is about half the maximum extension length of one Inner box corresponds.

In Fig. 5 is in three schematic representations similar to Fig. 3 as a longitudinal section Boom 1 shown, the two cylinder / piston systems 7, 8 each with two securing and locking units 12a, 15a and 12b, 15b are provided. A first upper locking and locking unit 15a is at the head end of the cylinder 13 of the cylinder / piston system 8 and a first lower fuse and Locking unit 12a arranged at the foot end of the cylinder 13. The other Cylinder / piston system 7 is a pull frame 11 at the head end of the extendable Piston rod 10 attached, the tension frame 11 extending into the foot area of the Cylinder / piston system 7 extends (in the retracted state) and there with a second lower locking and locking unit 12b is provided while a second upper securing and locking unit 15b at the head end of the extendable Piston rod 10 is arranged. The three partial representations of FIG. 5 show the case that the cylinder / piston systems 7, 8 to achieve a maximum telescopic force in Be operated synchronously. In the upper illustration, both have cylinder / piston systems 7, 8 with their lower securing and locking units 12a, 12b innermost inner box 3 extended to half the extended position. In this position is locked with the next larger inner box 4 and after uncoupling from the inner box 3 then the return of the two cylinder / piston systems 7, 8 in the starting position, which is shown in the middle representation. In this position then couple the two upper securing and locking units 15a, 15b, unlock the inner box 3 and drive it shown in the illustration below End position, lock it and then drive back to the next one To move the inner box in a corresponding manner.

The present invention enables telescopic times for a telescopic boom realize that largely correspond to the times that a fully hydraulic telescopic system can be achieved. At the same time, however, it becomes clear Weight reduction possible for the hydraulic system to be used.

COVERS LIST:

1 telescopic boom 2 basic box 3 inner box 4 inner box 5 inner box 6 inner box 7 first hydraulic cylinder / piston system 8th second hydraulic cylinder / piston system 9 cylinder 10 piston rod 11 towing frame 12, 12a, 12b Security and locking unit 13 cylinder 14 piston rod 15, 15a, 15b Security and locking unit 16 Attachment to the base of the base box 17 Attachment to the base of the base box 18 pivot bearing 19 camp 20 coupling element 21 coupling element 22 locking bolt 23 fixtures 24 Ankoppelöffnung 25 Ankoppelöffnung 26 slide 27 slide 28 bearings 29 bearings 30 grab 31 grab 32 guide

Claims (14)

Telescopic boom, in particular telescopic boom (1) for a mobile crane, with a basic box (2) in which one or more inner boxes (3 - 6) are guided essentially coaxially into one another, which are successively guided by a first hydraulic cylinder / piston system (7) are optionally retractable or extendable, the first hydraulic cylinder / piston system (7) being fixed in one of its two axial ends (foot region) in the basic box (2) and with its extendable part by means of a first coupling device (securing and locking unit 12 ) can be coupled to the inner box (3 - 6) to be moved and the respective inner box (3 - 6) can be locked in its retracted and extended positions with respect to the next larger inner box (4 - 6) or the basic box (2) and immediately before the method can be unlocked after the coupling has been carried out,
characterized in that a second hydraulic cylinder / piston system (8) is arranged parallel to the first hydraulic cylinder / piston system (7), which is also fixed with one of its two axial ends in the basic box (2) and with its extendable Part by means of a second coupling device (securing and locking unit 15) can be coupled to the inner box (3 - 6) to be moved in each case and that the two cylinder / piston systems (7, 8) can be operated in opposite directions. Telescopic boom according to claim 1,
characterized in that the two cylinder / piston systems (7, 8) can optionally also be operated in synchronism and at the same time can be coupled to the same inner box (3-6). Telescopic boom according to one of claims 1 to 2,
characterized in that the extendable length of the two cylinder / piston systems (7, 8) is in each case significantly smaller than the extendable length of the respective inner box (3 - 6) and that the respective inner box (3 - 6) by means of the first hydraulic cylinder / Piston system (7) from the retracted position over a first section of the entire extendable length of the inner box (3 - 6) and by means of the second hydraulic cylinder / piston system (8) over a second section of the total extendable length of the inner box ( 3 - 6) can be moved to its end position. Telescopic boom according to claim 3,
characterized in that the extendable length of the two cylinder / piston systems (7, 8) is in the range from 40% to 60% of the greatest extendable length of an inner box (3 - 6), in particular 50% of this length. Telescopic boom according to one of claims 1 to 4,
characterized in that each cylinder / piston system (7, 8) as a coupling device has two locking and locking units (12a, 15a or 12b, 15b), one of which is located in the area of one axial end (foot area) and the another is arranged in the area of the other axial end (head area) of the cylinder / piston system (7, 8) (based on the retracted position). Telescopic boom according to one of claims 1 to 4,
characterized in that the two cylinder / piston systems (7, 8) are each provided as a coupling device with only one locking and locking unit (12, 15) which is displaceable in the axial direction and at both ends of the respective cylinder / piston system (7, 8) can be locked. Telescopic boom according to one of claims 1 to 4,
characterized in that the two cylinder / piston systems (7, 8) are each provided as a coupling device with only one locking and locking unit (12, 15), one of which, in the retracted state, in the area of one axial end (foot area) one cylinder / piston system (7) and the other (15) in the region of the other axial end (head region) of the other cylinder / piston system (8). Telescopic boom according to one of claims 1 to 6,
characterized in that the two cylinder / piston systems (7, 8) are designed for different telescopic forces, in particular have different diameters from one another. Telescopic boom according to one of claims 1 to 8,
characterized in that the two cylinder / piston systems (7, 8) are arranged one above the other with respect to the load plane of the telescopic boom. Telescopic boom according to claims 8 and 9,
characterized in that the cylinder / piston system (7) with the smaller diameter is arranged above the cylinder / piston system (8) with the larger diameter. Telescopic boom according to one of claims 1 to 10,
characterized in that the two cylinder / piston systems (7, 8) are supported on one another, in particular via slide rails (26). Telescopic boom according to one of claims 3 to 11,
characterized in that at least one of the cylinder / piston systems (7, 8) is fixed with its cylinder (9, 13) in the basic box (2) and the piston rod (10, 14) the movable part of the cylinder / piston system ( 7, 8) forms. Telescopic boom according to claim 12,
characterized in that the securing and locking unit (12) of the first cylinder / piston system (7) is fastened to a pull frame (11) which is coupled to the extendable end of the piston rod (10) and extends along in the retracted position of the cylinder (9) extends into the foot region of the cylinder (9) (draw frame construction). Telescopic boom according to claim 3 and one of claims 8 to 11,
characterized in that the first cylinder / piston system (7) has a smaller diameter than the second cylinder / piston system (8) and is fixed with its cylinder (9) in the basic box (2) and with respect to its only locking and locking unit (12) is designed in a pull frame construction and that the second cylinder / piston system (8) with its piston rod (14) is fixed in the basic box (2) and its only locking and locking unit (15) at the upper end of its extendable cylinder (13) is attached.

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