EP1404606A1

EP1404606A1 - Mobile crane comprising a telescopic principal jib

Info

Publication number: EP1404606A1
Application number: EP02748566A
Authority: EP
Inventors: Michael Irsch; Alexander Knecht; Jens Fery
Original assignee: Terex Demag GmbH and Co KG
Current assignee: Terex Demag GmbH and Co KG
Priority date: 2001-06-11
Filing date: 2002-05-31
Publication date: 2004-04-07
Also published as: JP2004528255A; US20040168997A1; US7172082B2; WO2002100756A1; DE10128986A1

Abstract

The invention relates to a mobile crane comprising a chassis (20) and a revolving superstructure (21) that is rotatably mounted on said chassis (20). Said chassis has a principal jib (22), which is composed of a base body (1) and several telescopic lengths (2-5) up to a predetermined maximum number, which slide into one another and can be extended from the base body (1). The principal jib (22) is mounted on the revolving superstructure (21) so that it can rotate about a horizontal axis and its inclination can be adjusted by means of a hydraulic tilting cylinder (23) that is hinged on the revolving superstructure (21) and the base body (1). A maximum permissible weight is predefined for the principal jib (22), as a result of a restriction on the permissible axle load of the mobile crane during road haulage. The crane is also provided at least temporarily with a load increasing device (24), which significantly increases the load of the principal jib (22) when the telescopic lengths (2-5) are extended, in relation to the state without the load increasing device (24). The invention is characterised in that the load increasing device (24), as part of the standard basic equipment of the mobile crane, is connected in a fixed manner to the principal jib (22), whilst maintaining the maximum number of telescopic lengths that are carried.

Description

Mobile crane with telescopic main boom

description

The invention relates to a mobile crane with an undercarriage and a superstructure which is rotatably arranged on the undercarriage and which has a main boom formed from a basic box and a plurality of telescopic sections which are guided one inside the other and extendable from the basic box. The main boom is rotatably mounted on the superstructure about a horizontal axis and its inclination can be adjusted by means of a hydraulic luffing cylinder articulated on the superstructure and the basic box. For such a mobile crane, the limitation of the permissible axle loads of the mobile crane during a road transport is a maximum permissible one

Total weight of the main boom specified. The carrying capacity of the main boom, when the telescopic sections are extended, can be significantly increased compared to the state without a lifting device by means of a lifting device that is provided at least temporarily on the main boom.

Such a crane is known for example from DE 31 13763 A1. The lifting capacity device used there consists of a rope bracing made of two ropes that are almost parallel to the load level, i.e. to the plane spanned by the hoist rope and the longitudinal axis of the main boom. The ropes are fastened in the area of the upper end of the extended main boom and are guided over a guy stand, which is directed upwards approximately perpendicular to the longitudinal axis of the main boom. The other end of the guying is attached to the base of the main boom. This bracing significantly increases the rigidity and buckling strength of the extended boom in the load plane. This significantly increases the load capacity of the main boom.

A similar lifting capacity device in the form of a rope bracing is known from DE 198 02 187 A1. There, one end of the traction cable used for the guy is firmly connected to an auxiliary boom, which is at the head of the telescoped one Main boom is attached. The other end of the traction cable is in turn wound on a machine-operated cable drum, which is attached to a guy stand connected to the basic box of the telescopic boom. The traction rope is guided over a deflection roller at the top of the guy stand to the rope drum. The tip of the guy stand itself is connected to the foot of the base box of the telescopic boom by a part of the guy that has a fixed length. The entire guying therefore consists of a part of fixed length and a part of variable length. As a result, the length of the guying can easily be adjusted to the respective extension length of the telescopic boom.

Another lifting capacity device in the form of a rope bracing is known from EP 1 065 166 A2. The special feature here is that the guy stand is formed from two separate mast-like supports, both of which are set essentially perpendicular to the longitudinal axis of the telescopic boom, but which are attached to one another in a spread-apart manner, i.e. form an angle between them, for example in the range of 90 ° lies. When the boom is aligned horizontally, the two supports of the guy stand do not point vertically upwards, but are directed obliquely upwards. A guy rope attached to the upper end of the telescopic boom is guided via a deflection pulley to a rope drum over both supports of the guy stand. Of course, the cable drum could also be arranged directly at the tip of the respective support, so that a deflection roller would be dispensed with. The upper end of the supports is in turn connected to the foot area of the telescopic boom by means of a fixed-length bracing. Due to the spreading of the two supports of the guy bracket, the two guy ropes run at an angle to each other outside the load level. In this way, a stabilizing effect for the telescopic boom can be achieved in two levels, namely on the one hand within the load level and on the other hand transversely to the load level. In contrast to the two aforementioned lifting capacity devices, stabilization is also achieved in the side area of the telescopic boom.

The guy stand with rope drum and rope requires additional space on the telescopic boom, which is significantly reduced by the fact that the guy stand is designed to be foldable. However, this additional device also causes a considerable increase in weight. Because the boom weight in turn in the case of road transport of the respective mobile crane by limiting the permissible axle loads must not exceed a specified maximum limit, road transport of a mobile crane with a telescopic boom, which is equipped with a pre-assembled lifting device in the form of a rope bracing, is generally not permitted. Usually, the lifting capacity device has to be transported separately and installed on the respective construction site before the crane is used. A way out in this regard can occasionally be found in that one or more telescopic sections are temporarily removed from the boom in order to compensate for the weight increase by the lifting capacity increasing device. However, this has the disadvantage that the available maximum boom length is reduced accordingly.

Basically there is a desire to have a mobile crane with a telescopic boom available, in which the extendable boom length is as high as possible and at the same time the load capacity, i.e. the permissible lifting capacity is as high as possible. In principle, an increase in the load capacity can be achieved by a more solid design of the profiles used for the individual telescopic sections. However, this would in turn lead to a corresponding increase in weight, which is mostly not permitted due to the limitation of the permissible axle loads.

The object of the present invention is to improve a mobile crane of the generic type in such a way that the possible extension length for a given load capacity is increased significantly without an impermissible increase in the total boom weight and thus without exceeding the permissible axle loads, or for a given maximum extension length while observing the aforementioned boundary conditions, the permissible load capacity (Load capacity) is increased.

This object is achieved according to the invention by a mobile crane with the features mentioned in the characterizing part of patent claim 1. Advantageous developments of the inventions result from the subclaims.

The invention provides to provide the lifting capacity device, which was previously regularly installed as a special accessory on the mobile crane, as part of the standard basic equipment of the mobile crane, the maximum number of telescopic sections carried being permanently connected to the main boom. The This means that in order to compensate for the weight of the lifting device, there is no need to do without a telescopic boom. The weight of the lifting device is included in the main boom weight without exceeding the permissible maximum weight of the main boom without reducing the number of telescopic sections. This is possible because, in order to compensate for the weight of the payload increasing device, the individual weight of the telescopic sections is reduced in each case in such a way that the ratio of the head weight G _κ to the foot weight G of the fully extended main boom is at most 40:60. The head weight G «preferably makes up at most 38% of the total weight of the main boom. In practical cases, the ratio G _κ : G _{F is} in the range from 40:60 to 30:70. The total weight of the main boom is kept constant, as it were, compared to a conventional design in that the increase in weight by the lifting capacity device is compensated for by a reduction in the weights of the individual telescopic shots.

This reduction in weight of the individual telescopic sections can advantageously be achieved at least in part or entirely by reducing the wall thickness of the telescopic sections. In particular, it is advisable to reduce the thickness of the side walls, that is to say the walls lying parallel to the load plane. The associated reduction in the load-bearing capacity must at least be compensated for again by the load-increasing device.

Of course, it is also possible to reduce the individual weight of the telescopic sections at least in part or entirely

To reach the cross-sectional circumference of the telescopic sections. This can preferably be achieved by reducing the width of the cross section (transverse to the load plane), the height of the cross section remaining unchanged or being reduced less than the width of the cross section. However, it is also possible to reduce the height of the cross section while the width remains unchanged. Of course, a reduction in the cross-sectional circumference of the telescopic sections, which are generally designed as an essentially box-shaped profile. n Combination with a reduction in the wall thickness compared to the conventional cross-sectional design. The lifting capacity increasing device is preferably designed in such a way that it increases the rigidity of the main boom in the load plane. In this way, for example, a reduction in the height of the cross section and / or the wall thickness in the top flange and / or bottom flange of the telescopic weft profile can be compensated for.

If the width of the cross section of the individual telescopic sections is reduced and the height of the cross section remains unchanged or is reduced less, a lifting capacity device is used which is designed to increase the rigidity of the main boom across the load plane. However, it is particularly advantageous to use a lifting capacity device which increases the rigidity of the main boom both in the load plane and transversely thereto.

The carrying capacity increasing device is expediently designed in a manner known per se in the form of an anchoring which extends from the region of the upper end of the main boom to the region of the foot of the main boom. The upper attachment point of the guying does not have to be arranged at the outermost tip of the extended telescopic boom, but could also be connected, for example, to the collar of the penultimate or another telescoped telescopic section. Correspondingly, the lower one

Fastening point of the guying must not necessarily be attached to the outermost lower end of the boom foot. Other fastening points are also possible, for example in the area of the counterweights, which are usually fastened to the superstructure.

It is advisable to assemble the guying in a known manner from a part of variable length and a part of fixed length. The part of fixed length extends from the tip of the guy stand to the foot area of the main boom, while the part of variable length extends from the area of the upper end of the main boom to the cable drum on the guy stand. In principle, the lifting capacity device designed as a rope bracing can be formed from a single strand. In most cases, however, a mirror-image arrangement with regard to the load level is recommended, in that two separate guy lines are formed, which of course can in turn consist of a part of fixed length and a part of variable length. Accordingly, the Clamping bracket also has two separate guying supports, over which the guying is guided. The guy supports can be divided diagonally to one another, the included angle between their longitudinal axes being adjustable as possible as required. As a result, the degree of rigidity increase in the load plane and that across it can be varied. In this case, the degrees of stiffness change in opposite directions to each other.

In a further advantageous embodiment, the invention provides for the rope drum or rope drums to be easily dismantled, so that the respective rope drum with the guy rope wound thereon can be carried separately. As a result, the weight of the main boom can be reduced below a critical limit if necessary, without the need for major set-up work on the construction site for the production of the operational capability of the mobile crane. The cable drum or cable drums can then be used again without any major effort.

The present invention can be used with great advantage both in the case of smaller mobile cranes with e.g. three axes as with larger mobile cranes with z. B. use up to nine axes.

The invention is explained in more detail below on the basis of the exemplary embodiments illustrated in the figures. Show it

1 shows a mobile crane with the telescopic boom extended and the lifting capacity device,

2 shows the diagram of an extended telescopic boom,

3 shows a telescopic boom with a load increasing device acting in the load plane,

4 shows a telescopic boom with a lifting capacity device acting transversely to the load plane, 5 shows a telescopic extractor with a load increasing device acting both in the load plane and transversely thereto

Fg. 6 different profile cross sections for a telescopic shot.

The mobile crane shown in FIG. 1 has an undercarriage 20 which has a road chassis with eight axles. On the Unterwageπ 20 a superstructure 21 rotatable about a vertical axis is arranged. A main boom 22 is rotatably mounted on the superstructure 21 about a horizontal axis. In the present case, the main boom 22 consists of a basic box 1 and a total of four telescopic sections 2 to 5 that can be telescoped from the basic box. The horizontal swivel joint is arranged at the foot of the basic box 1. The inclination of the main boom 22 can be changed in any manner by means of a hydraulic luffing cylinder 23. The main boom 22 is provided with a schematically illustrated load-increasing device 24, which has a guy stand 8, which is directed upward on the back of the base box 1 approximately perpendicular to the longitudinal axis of the main boom 22. Other essential parts of the lifting capacity device 24 are the lower guying 10, which extends from the base of the base box 1 to the tip of the guy stand 8, and the upper guy 11, which leads from the area of the upper end of the main boom 22 to the guy stand 8. Usually that is

Length of the lower guy 10 fixed. This part of the lifting capacity device can therefore also be composed of tie rods. Of course, a fixed rope length can also be used. The upper guying 11 is expediently designed as a rope guying, since then the greatest flexibility is given with regard to the respective extension length of the telescopic boom 22. The length of the upper guying 11 can easily be varied by means of a cable drum 9.

The essence of the present invention is to be seen in the fact that, compared to a conventional design of the telescopic sections with comparable load capacities, the weights of the individual telescopic sections are reduced by the additional weight of a lifting device which is provided as standard on the main boom of the mobile crane and thus permanently with it is connected to compensate. This weight reduction in the telescopic sections leads to the distribution of the total weight of the telescopic boom on the Foot weight G _F and head weight G _κ , as shown in Fig. 2, shifts compared to a conventional design. According to the invention, the ratio of the head weight G _κ to the foot weight G _F is less than 40:60. The practical embodiments usually range in this range from 40:60 to 30:70. With a conventional design of the cross sections of the telescopic sections, this is Ratio G _κ : G _F regularly above 40:60, namely, for example at 42:58. In an advantageous embodiment of the invention, on the other hand, this ratio is, for example, about 38:62.

FIG. 3 shows an extended telescopic boom of the type according to the invention, which is provided with a lifting capacity increasing device designed only as a quasi single-strand guying. The two strands of bracing 11 shown in dotted form run parallel to each other at a relatively short distance and therefore, like an actually single-strand bracing, cannot bring about stabilization transverse to the load plane. The guy stand stands vertically upwards on the longitudinal axis of the boom and lies within the load level. The latter also applies to the lower guying 10 and the upper guying 11. The cable drum at the upper end of the guy stand 8 is designated by the reference number 9. Due to its design, this lifting capacity increasing device can only increase the rigidity and kink resistance of the telescopic boom in the direction of the load plane.

In contrast, FIG. 4 shows a telescopic boom with a load increasing device which increases the rigidity of the main boom transversely to the load plane. For this purpose, the guy stand is formed from two guy supports 8a, 8b, which extend horizontally to the left or right from the basic box 1 of the telescopic boom to the outside. Accordingly, two separate strands are also provided for the guying, which are designated by the reference numerals 10a, 11a and 10b, 11b and whose function otherwise corresponds to the guying in FIG. 3.

Another variant of a lifting capacity increasing device is shown in FIG. 5. This embodiment combines the effects of the embodiments according to FIGS. 3 and 4 with one another. For this purpose, the guy stand is again made up of two guy supports 8a, 8b formed, which also extend perpendicular to the longitudinal axis of the telescopic boom to the left and right, but which enclose an angle between them, which is indicated by corresponding double arrows. The two guy supports 8a, 8b are spread apart upwards. This results in force components in the bracing in the direction of the load plane and transversely to it. Therefore, this type of lifting capacity device can increase the rigidity and kink resistance of the telescopic boom not only in the load plane but also across it. The angle between the two guy supports 8a, 8b can preferably be set to an angle in the range from 0 ° to 180 ° as required.

In Fig. 6 different profiles for profile shots are indicated schematically in the sub-figures a to e. The cross-sectional shape is essentially box-shaped, with the corners rounded. In the lower part of the profile, however, the radius of curvature is considerably larger than in the upper part of the profile. In the partial figure a, a cross section is shown, that of a conventional design of a

Telescopic boom shot corresponds. The selected wall thickness has been deliberately exaggerated compared to an actual embodiment in order to better illustrate the direction of the deviations of a profile design according to the invention. Part b shows that the side walls are reduced in their wall thickness compared to the conventional shape a, as indicated by the arrows. According to the invention, the weakening of the wall thickness in the side areas is more than compensated for by a corresponding load-increasing device, so that an overall increase in the load capacity is achieved. Sub-figure c indicates that in addition to the side walls, the lower flange and the upper flange can also be subjected to a wall thickness weakening. It can be seen from sub-figure d that the weight reduction of the respective telescopic boom section can also be achieved by reducing the width of the profile. In the case of the partial figure e, this reduction in weight has been achieved by reducing the height of the profile.

Claims

claims:

1. Mobile crane with an undercarriage (20) and an upper carriage (21) which is rotatably arranged on the undercarriage (20) and which consists of a basic box (1) and a plurality of one another, which are guided into one another up to a predetermined maximum number and from the basic box (1) extendable telescopic sections (2 - 5) formed main boom (22), the main boom (22) rotatable about a horizontal axis on the superstructure

(21) is mounted and its inclination can be adjusted by means of a hydraulic luffing cylinder (23) articulated on the superstructure (21) and on the basic box (1), the maximum permissible weight of the main boom being further limited by limiting the permissible axle loads of the mobile crane during road transport (22) is specified and at least temporarily a payload increasing device (24) is provided which significantly increases the payload of the main boom (22) when the telescopic sections (2-5) are extended compared to the state without the payload increasing device (24), characterized in that the carrying load increasing device (24) as part of the standard basic equipment of the mobile crane while maintaining the maximum number of telescopic shots carried (2 - 5) permanently with the main boom

(22) is connected, the weight of the payload increasing device (24) being included in the main boom weight without exceeding the permissible maximum weight of the main boom (22) without a reduction in the number of telescopic shots (2-5) and wherein to compensate for the weight of the

Load increasing device (24) the individual weight of the telescopic sections (2 - 5) is reduced in each case in such a way that the ratio of the head weight G _κ to the foot weight G _{F of} the fully extended main boom (22) is a maximum of 40:60.

2. Mobile crane according to claim 1, characterized in that the reduction in the individual weight of the telescopic sections (2-5) at least in part by a reduction in the wall thickness of the telescopic sections (2-5), in particular in the side walls (parallel to

Load level).

3. Mobile crane according to one of claims 1 to 2, characterized in that the reduction in the individual weight of the telescopic sections (2-5) is achieved at least in part by a reduction in the cross-sectional circumference of the telescopic sections (2-5).

4. Mobile crane according to claim 3, characterized in that the width of the cross section of the telescopic sections (2 - 5) is reduced (transverse to the load plane) and the height of the cross section is unchanged or less greatly reduced

5. Mobile crane according to claim 3, characterized in that the height of the cross section of the telescopic sections (2-5) is reduced.

6. Mobile crane according to claim 5, characterized in that the lifting capacity increasing device (24) is designed to increase the rigidity of the main boom (22) in the load plane.

7. Mobile crane according to claim 4, characterized in that the lifting capacity increasing device (24) is designed to increase the rigidity of the main boom (22) transversely to the load plane.

8. Mobile crane according to one of claims 1-5, characterized in that the lifting capacity increasing device (24) is designed to increase the rigidity of the main boom (22) both in the load plane and transversely thereto.

9. Mobile crane according to claim 8, characterized in that the lifting capacity increasing device (24) is designed to be adjustable in such a way that the degree of rigidity increase in the load plane and that transverse to it can be varied, in particular can be varied in opposite senses.

10. Mobile crane according to one of claims 6-9, characterized in that the lifting capacity increasing device (24) is a guy that extends from the area of the upper end of the main boom (22) to the area of the foot of the main boom (22).

11. Mobile crane according to claim 10, characterized in that the guying comprises at least one guy rope (11, 11 a, 11 b), at least one guy stand (8, 8a, 8b) and at least one rope drum (9, 9a, 9b)

12. Mobile crane according to claim 11, characterized in that the guying comprises a part of fixed length (10, 10a, 10b).

13. Mobile crane according to claim 9 and one of claims 11 - 12, characterized in that the guy bracket (8) is formed from two guy supports (8a, 8b), the longitudinal axes of which can be brought into different angular positions with respect to one another, and that the guy guy two guy cables ( 11 a, 11 b).

14. Mobile crane according to one of claims 10-13, characterized in that the cable drum (9, 9a, 9b) with the guy rope (11, 11a, 11b) wound thereon is easily dismantled and can be carried separately. ^•

15. Mobile crane according to one of claims 1-14, characterized in that the mobile crane has a chassis with three to nine axles.